CN1774871A - Directional speakers - Google Patents

Abstract

Different embodiments of the invention are based on a directional speaker. The audio signals from the speaker can be generated by transforming ultrasonic signals in air. The embodiments can be applied to a number of different areas, such as a cell phone, a hearing aid, a portable device, an entertainment system, and a computation system. The embodiments can be personalized to the hearing characteristics of the user, or to the ambient noise level of the environment. As applied to cell phones or portable electronic devices, the outputs from some of those embodiments can be in a directionally constrained manner, achieving a certain degree of privacy, without the need to wear a headset or ear phone, or to hold a speaker against one's ear, while freeing up both of the user's hands. As applied to a hearing aid, some of those embodiments do not have to be inserted into the user's ear. As applied to audio output systems, the directional delivery of audio output from some of those embodiments can be targeted to those one or more persons desirous of hearing the audio output. A number of the attributes of the audio output, such as its beam width, beam direction, the degree of isolation and the volume, can be controlled, either by a user or by monitored measurements. As applied to wireless delivery of audio sounds from audio systems to personal audio devices, some of those embodiments permit users of the personal audio device to be mobile yet still acquire the audio sounds.

Description

Directional loudspeaker

Background

Technical Field

The present invention relates generally to electronic devices for audio output, and more particularly to directional speakers.

Description of the related Art

Cell phones and other wireless communication devices have become an integral part of our lives. However, there are various problems and challenges that accompany the rapid proliferation of these devices.

For example, there remains a need for improved methods of enabling wireless communication devices, such as cell phones, to be used hands-free. The mobile phone users can carry out conversation more conveniently without placing earphones on ears, and meanwhile, certain privacy is kept.

A significant portion of people have some degree of deafness in their mouths. There is still a need to improve the level of skill to help those with mild or moderate hearing impairment.

Audio systems, such as stereo systems (stereo systems), DVD players and televisions, generally provide audio sound to more than one user. There is also a need for improved methods for these systems to provide sound only to specific recipients, while reducing interference to other surrounding people who do not wish to hear the sound.

There is also a need for a method of enhancing the wireless transmission of audio sounds between an audio system and a personal audio device located a distance from the system.

Disclosure of Invention

Some embodiments of the invention are based on directional loudspeakers. The audio signal emitted by the loudspeaker can be generated by the conversion of an ultrasonic signal in air. The different embodiments can be applied in many different fields, such as mobile phones, hearing aids, portable electronic devices, and entertainment systems. These embodiments can be personalized to the hearing characteristics of the user or adjusted to the ambient noise level of the use environment.

One embodiment may be applicable to wireless communication systems, such as cell phones. The system may include an interface unit and a base unit. The audio signal emitted from the speaker can be received in a hands-free manner while also enhancing privacy protection. The interface unit may be attached to or directly inside the garment at the user's shoulder so that the audio signal from the speaker is transmitted to one of the user's ears.

Another embodiment is to provide a hearing enhancement system that achieves user hearing enhancement on a directional speaker position basis. The system may include an interface unit having a directional speaker and a microphone. Wherein, the microphone captures the input audio signal and then converts the audio signal into an ultrasonic signal. The speaker transmits these ultrasonic signals and converts them in air into audio output signals. To improve the hearing ability of the user, at least a portion of the audio output signal should be higher in power than the input signal. Based on this system, the user's ear may not have to be plugged with anything, thereby avoiding a feeling of annoying ear occlusion. This system is considerably cheaper than existing hearing aid devices. For example, it does not require the formation of an ear mold for personal sizing.

Yet another embodiment is the use of directional speakers in a portable electronic device, such as a handheld game console, to direct audio output in a directionally limited manner. The audio output is thus kept private to a certain extent, and in addition the user does not need to wear headphones or earphones, nor does the user need to hold the speakers against the ears, which leaves the user's hands free. The directional speaker may be integrated with the portable electronic device or alternatively attached or connected to the portable electronic device.

One embodiment is directed to a directional audio device, such as an entertainment system, that provides directional delivery of audio output to those (one or more) willing to listen to the audio output. In this way, other people who do not wish to hear the audio output do not receive the audio output significantly and are therefore little disturbed by the audio sounds they do not need. The directional audio device comprises a directional loudspeaker. Many properties of the audio output may be controlled by user or monitoring measurements. These attributes include beam width, beam direction, acoustic level or privacy, and volume of audio output. The audio output may also be personalized or adjusted according to the audio conditions surrounding the device. A variety of methods may be employed to control these attributes or characteristics. For example, segmenting or bending the surface of the speaker, changing the ultrasonic frequency, adjusting the phase of individual speaker components, or lengthening the ultrasonic path length before the speaker's emitting surface reaches free space. In addition, more than one speaker may be used to create the stereo effect.

Another embodiment of the present invention includes techniques for wirelessly communicating audio sounds from an audio system to a personal audio device. These techniques allow the user of the personal audio device to still obtain audio sounds while in motion. According to an aspect of the invention, the wireless adapter may be used as an after market modification (after market modification) for the audio system.

Other aspects and advantages of the invention will be apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

Brief Description of Drawings

The principles of the present invention may be understood more readily by reference to the following detailed description, taken in conjunction with the accompanying drawings, which include reference numerals, structural elements, and the like,

fig. 1 shows an embodiment of the invention, a base unit connected to a directional loudspeaker and a microphone.

Fig. 2 is a characteristic illustration of the directional speaker of the present invention.

Fig. 3 is a mechanism illustration of the audio signal direction setting of the present invention.

FIG. 4A shows a Blazed grating embodiment of the present invention.

Fig. 4B shows an example of a wedge for guiding the propagation angle of an audio signal according to the present invention.

Fig. 5 shows an example of a controllable phase array (steerable phase array) of the apparatus of the present invention for generating a directional audio signal.

Fig. 6 is an example of an interface element attached to a user's clothing in the present invention.

Fig. 7 illustrates the principle of the mechanism of attaching the interface unit in the user's clothing in the present invention.

Fig. 8 illustrates various different connection techniques between the interface unit and the base unit in the present invention.

Fig. 9 illustrates various additional attributes of the wireless communication system of the present invention.

Fig. 10 illustrates the nature of the power supply used by the present invention.

Fig. 11A is an illustration of a hands-free or regular telephone employing an embodiment of the present invention.

FIG. 11B is a different technical example of automatic mode selection for a dual mode phone employing the present invention.

Fig. 12 shows a different embodiment of the interface unit of the invention.

FIG. 13 illustrates various additional applications of the present invention.

Fig. 14 illustrates another embodiment of the present invention.

Fig. 15 shows a user wearing an embodiment of the invention.

Fig. 16 shows a different embodiment of the invention with respect to frequency dependent amplification.

Fig. 17 shows some embodiments of the invention with respect to calibration.

Fig. 18A shows some embodiments of the invention with respect to power management.

Fig. 18B shows an embodiment of an interface unit with electrical connections.

Fig. 19A-19C show different embodiments of the invention with respect to a microphone.

Fig. 20 illustrates embodiments of the present invention, which may also be used as a telephone.

Fig. 21 is a call processing flow diagram of one embodiment of the present invention.

FIG. 22 is some embodiments of the invention relating to improving privacy.

FIG. 23 illustrates various embodiments of the present invention for receiving audio signals from other instruments over a wireless or wired connection.

Fig. 24A is a schematic diagram of a mobile phone integrated with a directional speaker according to one embodiment of the present invention.

Fig. 24B is a perspective view of a flip-type mobile phone with an integrated directional speaker according to another embodiment of the present invention.

Fig. 25 is a perspective view of a Personal Digital Assistant (PDA) integrated with a directional speaker according to one embodiment of the present invention.

Fig. 26 is a block diagram of an electronic device with wireless communication capabilities, in accordance with one embodiment of the present invention.

Fig. 27A is a block diagram of a directional audio conversion device, according to an embodiment of the present invention.

FIG. 27B is a block diagram of a preprocessor, according to an embodiment of the present invention.

FIG. 27C is a block diagram of an evaluation circuit of a preprocessor, according to an embodiment of the present invention.

Fig. 28 illustrates different embodiments of directional loudspeaker characteristics according to the present invention.

Fig. 29 is a flow diagram of audio signal processing according to an embodiment of the present invention.

Fig. 30 is a flow diagram of a speaker selection process, according to one embodiment of the invention.

The schematic diagram of fig. 31 lists some examples of exemplary conditions by which speakers may be selected.

Fig. 32A is a perspective view of a handheld computer having an attachable directional speaker, in accordance with an embodiment of the present invention.

Fig. 32B is a perspective view of a handheld computer having an attachable directional speaker, in accordance with another embodiment of the present invention.

Fig. 33 is a perspective view of a mobile phone with another attachable directional speaker, in accordance with one embodiment of the present invention.

FIG. 34 is a schematic diagram depicting examples of additional applications associated with the present invention.

Fig. 35 is a block diagram of a directional audio transmission device connected to an audio system, in accordance with an embodiment of the present invention.

Fig. 36A is a block diagram of a directional audio transmission device, according to one embodiment of the present invention.

Fig. 36B is a block diagram of a directional audio transmitting device according to another embodiment of the present invention.

Fig. 37A is a schematic diagram illustrating an example of an apparatus suitable for use in various embodiments of the invention.

FIG. 37B is a schematic plan view of a representative embodiment of an application of the present invention.

Fig. 38 is a flow diagram of a directional audio transmission process according to one embodiment of the invention.

Fig. 39 is an illustration of the properties of a limited audio output signal according to the present invention.

FIG. 40 is another example of a schematic plan view showing an application of the present invention.

Fig. 41 is a flowchart illustrating a directional audio transmission process according to another embodiment of the present invention.

Fig. 42A is a flow diagram illustrating a process for directional audio transmission according to yet another embodiment of the present invention.

FIG. 42B is a flowchart of an environment adaptation process, according to one embodiment of the invention.

FIG. 42C is a flowchart of an audio personalization process, according to one embodiment of the present invention.

FIG. 43A is a perspective view of an ultrasonic transducer, according to one embodiment of the invention.

Fig. 43B is a schematic diagram illustrating an ultrasonic transducer according to one embodiment of the invention that produces a beam as an audio output.

Fig. 43C-43D illustrate two embodiments of the present invention in which the directional loudspeaker is segmented.

Fig. 43E-43G illustrate the variation of beamwidths for different carrier frequencies, in accordance with one embodiment of the present invention.

Fig. 44A-44B are schematic diagrams of two embodiments of the present invention, bending the directional loudspeaker face to expand the beam.

FIG. 44C shows beam expansion based on a convex mirror, in accordance with one embodiment of the present invention.

Fig. 45A-45B show two embodiments of the invention with directional loudspeakers having segmented curved surfaces.

Fig. 46A and 46B illustrate perspective views of an audio system with a directional audio transmission device in a set-top box environment, in accordance with various embodiments of the present invention.

FIG. 47 is a perspective view of a remote control device, in accordance with one embodiment of the present invention.

Fig. 48A-48B illustrate two embodiments of the present invention that allow for directional audio transmission of ultrasonic signals for multiple bounces back and forth before transmission into free space.

Fig. 49 shows two spaced apart directional audio transmission devices producing a stereo effect, in accordance with one embodiment of the present invention.

Fig. 50 is a block diagram of a remote controlled audio transmission system according to an embodiment of the present invention.

Fig. 51 is a block diagram of a remote controlled audio transmission system according to another embodiment of the present invention.

Fig. 52 is a block diagram of a remote controlled audio transmission system according to yet another embodiment of the present invention.

FIG. 53 is a build configuration diagram illustrating the use of various embodiments of the present invention.

Fig. 54 is a flow diagram of a remote controlled audio transmission system, in accordance with an embodiment of the present invention.

FIG. 55A is a flow diagram of an environment adaptation process, according to one embodiment of the invention.

FIG. 55B is a flowchart of an audio personalization process, according to one embodiment of the present invention.

56A-B illustrate an ultrasonic transducer according to one embodiment of the invention.

FIG. 57 is a perspective view of an audio system providing directional audio delivery to a user of interest.

Detailed Description

Various embodiments of the invention are discussed below, with reference to fig. 1-57. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the invention extends beyond these limited embodiments.

One embodiment of the present invention is a wireless communication system that provides a better hands-free method of use. This wireless communication system may be, for example, a handset. Fig. 1 shows a block diagram of a wireless communication system 10 according to one embodiment of the invention. The wireless communication system 10 has a base unit 12 coupled to an interface unit 14. The interface unit 14 includes a directional speaker 16 and a microphone 18. Directional loudspeaker 16 produces a directional audio signal.

According to the basic aperture antenna theory (aperture antenna theory), the angular beam width θ of a sound source such as a directional loudspeaker is approximately λ/D, where θ is the angular full width at half maximum (FWHM), λ is the wavelength, and D is the aperture diameter. For simplicity, the apertures are assumed to be circular.

For common audible signals, the frequency ranges from a few hundred hertz, such as 500 hertz, to a few kilohertz, such as 5000 hertz. Since the speed c of sound in space is 340 m/s, the wavelength λ of a normal audible signal is approximately between 70 cm and 7 cm. For personal or portable applications, the size of the speaker may be on the order of a few centimeters. Such loudspeakers are almost omni-directional, i.e. the sound source emits energy uniformly in almost all directions, depending on the wavelength of the sound wave being much larger than a few centimeters. This is not a desirable result if the user requires privacy, as an omni-directional sound source means that the audio signal may be intercepted by a person in any direction.

One solution to enhance the directivity of sound sources is to reduce the wavelength of the sound waves, but this may cause the acoustic frequencies to go beyond the audible range. Another technique is known as parametric acoustics (parametric acoustics).

Parametric acoustic operations (Parametric acoustic operations) have been previously discussed, for example, in the following publications: "Parametric Acoustic Array", P.J.Westervelt, in J., Acoust.Soc.am, Vol.35(4), pp.535-537, 1963; "positional amplification of Non-Linear Acoustics in underwater transmission Applications" (Possible development of nonlinear Acoustics in underwater transmission Applications) ", h.o. berktay, in j.sound vib. vol.2 (4): 435, 461 (1965); and "Parametric Array in Air", Bennett et al, in J.Acoust.Soc.Am., Vol.57(3), pp.562-568, 1975.

In one embodiment, the audible sound wave signal is assumed to be f (t), where f (t) is a band-limited signal, such as a frequency from 500Hz to 5,000 Hz. Generation of a modulation signal f (t) sin omega by sinusoidal modulation_ct to drive the acoustic wave transducer. Carrier frequency omega_cThe/2 pi should be much larger than the highest frequency component of f (t). In the case where the carrier is ultrasonic, the acoustic transducer should be at ω_cThe dots have sufficient bandwidth to cover the frequency band of the input signal f (t). Signal f (t) sin ω_ct is emitted from the transducer and is subjected to non-linear demodulation in air to produce an audible signal e (t), where,

E(t)∝*²/*t²[f²(τ)]

where τ is t-L/c and L is the distance between the sound wave generating source and the sound wave receiving location. In this example, the demodulated audio signal is proportional to the second time derivative of the square of the modulation envelope f (t).

In order to more accurately find the audio signal f (t), the original audio signal may be pre-processed in various ways before the signal is input to the transducer. Each method has its own features and advantages. Davy in 1972 his university of texas at austin university (u.t.austin) major paper "Acoustic Self-demodulation of Pre-distorted Carriers" set forth one of the preprocessing methods. The technique described therein integrates the signal f (t) twice, square roots the result, and multiplies the result by the sine carrier sin ω_ct, the resulting signal is applied to the transducer. During such processing, infinite harmonics of f (t) may be generated, and the limited transmission bandwidth may produce distortion.

Another pretreatment method is described in "The audio spotlight: the application of the nonlinear interaction of sound waves to a new type of loudspeaker design "article (written by Yoneyama et al, journal of the american acoustic association 1)Vol.73(5), pp.1532-1536) at 5 months 983. This pre-processing method relies on Double Sideband (DSB) modulation. Let s (t) be 1+ mf (t), where m is the modulation factor. S (t) sin ω_ct is used to replace f (t) sin ω_ct drive the acoustic wave transducer. So that the following formula is established,

E(t)∝*²/*t²[S²(τ)]∝2mf(τ)+m²*²/*t²[f(τ)²].

the first term provides the original audio signal. But the second term will produce unwanted distortion as a result of the DSB modulation. One of the ways to reduce the distortion is to lower the modulation factor m. However, lowering the modulation factor m may also lower the overall power efficiency (power efficiency) of the system.

In the 10 th international conference on nonlinear acoustics document 1984, "Development of a parametric loudspeaker for practical use", by Kamakura et al (pp.147-150), another preprocessing method is described which eliminates undesirable terms. It is defined by the definition of S (t) [ < 1 > + mf (t)]^1/2A Modified Amplitude Modulation (MAM) technique is used. That is, the demodulated signal E (t) · mf (t). The square root envelope operation of the MAM signal may increase the bandwidth of s (t) and may require an infinite transmission bandwidth for distortion-free demodulation.

In the text "Suitable Modulation of the Carrier Ultrasound for a parametric Loudspeaker" (Acoustics, Vol.23, pp.215-217, 1991), Kamakura et al describe another pre-processing scheme, called "envelope Modulation". In this scheme, s (t) ═ e (t) + mf (t)]^*Where e (t) is the envelope of f (t). With this scheme, the transmit power is reduced by more than 64% and the distortion is better than Double Sideband (DSB) or Single Sideband (SSB) modulation, as detailed in "Self-modulation of a plane-wave-Study on primary wave modulation for wireless signal transmissionSelf-demodulation of surface waves-study of dominant wave modulation in broadband signal transmission) "article (written by Aoki et al, j.acoust.soc.jpn. vol.40, pp.346-349, 1984).

Returning to the directional topic, the modulated signal S (t) sin ω is compared to the original acoustic signal f (t)_ct or f (t) sin ω_ct has better directivity because of ω_cAbove audible frequencies. E.g. ω_cCan be equal to 2 π × 40kHz, but experiments have shown ω_cCan range from 2 π × 20kHz to over 2 π × 1 MHz. However, in general, ω is because the acoustic absorption is also higher at higher carrier frequencies_cIt is not preferable to choose too high. In summary, when ω is_cEqual to 2 pi x 40kHz, the frequency of the modulated signal is about 10 times higher than the audible frequency. This makes a small area of the emission source (e.g., 2.5 cm in diameter) a directional device suitable for a wide range of audio signals.

In one embodiment, the correct operating carrier frequency ω is selected_cMany factors need to be considered, such as:

to reduce approximately ω_c ²Proportional sound wave attenuation (acoustication), carrier frequency ω_cShould not be too high.

The FWHM of the ultrasound beam should be large enough, e.g. 25 degrees, to cover enough the head range of motion of the user wearing the portable device and to reduce the ultrasound intensity by beam expansion.

To avoid near field effects that may lead to amplitude fluctuations, the distance R between the transmitting device and the receiving site should be greater than 0.3 xr₀Where R is₀Is the Rayleigh distance, defined as (area of emission/λ).

For example, when the FWHM is equal to 20 degrees,

θ＝λ/D＝(c2π/ω_c)/D～1/3。

assuming D equals 2.5 cm, ω_cIs 2 π × 40 kHz. From the relationship of the above formulaThe directionality of the ultrasonic beam can be changed by changing the carrier frequency ω_cTo adjust. If an acoustic transducer with a smaller aperture is chosen, the directionality may be reduced. It is also noted that the power generated by the acoustic transducer is generally proportional to the area of the aperture. In the above example, the Rayleigh distance R₀About 57 mm.

Thus, in one embodiment, the smaller aperture speaker 16 may also generate a directional audio signal from the modulated ultrasonic signal. These modulated signals may be demodulated in air to produce an audio signal. Thus, the speaker can generate a directional audio signal even if it is emitted from a small hole of the order of several centimeters. This allows the directional audio signal to be directed in the desired direction.

There have been some examples described above in relation to the generation of an audio signal from a demodulated ultrasonic signal. However, the audio signal can also be generated by mixing two ultrasonic signals, the difference frequency of which is the audio signal.

Fig. 2 illustrates various characteristics of a directional loudspeaker. The directional loudspeaker may be, for example, the directional loudspeaker 16 illustrated in fig. 1. It may be a piezoelectric film. The piezoelectric film may be deposited on a plate consisting of a plurality of cylindrical tubes. One example of such a device is described in U.S. patent No.6,011,855, which is incorporated by reference herein. The thin film may be a polyvinylidene fluoride (PVDF) film and may be biased by a metal electrode (biased). The film may be attached or bonded to the entire flat sheet with the cylindrical tube. The total emitting surface area of all these tubes is of the order of magnitude of several wavelengths of the carrier or ultrasonic signal. Appropriate voltages are applied to the piezoelectric film through the electrodes to vibrate the film to generate a modulated ultrasonic signal. These signals cause the closed cylindrical tube to resonate. After the ultrasonic signal is emitted from the film, the ultrasonic signal is self-demodulated in the air through nonlinear mixing to generate an audio signal.

As an example, the piezoelectric film thickness may be about 28 microns; the diameter of the cylindrical tubes was 9/64 inches, the cylindrical tubes were spaced 0.16 inches apart on center, and the resulting resonant frequency was about 40 kHz. When the ultrasonic signal is mainly around 40kHz, the emitting surface area of the directional speaker is about 2 cm x 2 cm in size. The ultrasonic power generated by the directional loudspeaker can in fact be limited for the most part to the extent of a cone.

To calculate the amount of ultrasonic energy in this cone, for example, a rough estimate, assuming (a) that the emitting surface is a uniform circular hole 2.8 cm in diameter, (b) that the ultrasonic signal has a wavelength of 8.7 mm, and (c) that all of the energy is concentrated in the front hemisphere, the amount contained in the full width at half maximum (FWHM) of this main lobe is approximately 97% of the total energy of the ultrasonic energy signal, and the range from zero to zero (from null to null) of the main lobe contains approximately 97.36% of the total energy of the ultrasonic energy signal. Similarly, and again as a rough estimate, if the diameter of the hole is reduced to 1 cm, the energy contained within the full width at half maximum of the main lobe is approximately 97.2% of the total energy of the ultrasonic energy signal, while the energy contained within the main lobe ranging from zero to zero is approximately 99% of the total energy of the ultrasonic energy signal.

Referring back to the example of the piezoelectric film, the full width at half maximum (FWHM) of the signal beam is approximately 24 degrees. It is assumed that such a directional loudspeaker 16 is arranged on the clothing of the shoulder of the user. The output of the speaker is directed toward one of the user's ears, assuming that the distance between the user's shoulders and ears is 8 inches. The energy of the audio signal produced by the directional loudspeaker radiating surface is limited to the extent of a cone, in practice, by more than 75%. The top end of this cone is on the speaker and the open end is at the position of the user's ear. The diameter of the open end of the cone, or the diameter of the cone near the ear, is less than 4 inches.

In another embodiment, the directional speaker may be fabricated from a bimorph piezoelectric transducer (bimorph piezoelectric transducer). The transducer may have a cone with a diameter of about 1 cm. In yet another embodiment, the directional speaker may be a magnetic transducer. In addition, there is an embodiment in which the directional speaker does not generate an ultrasonic signal, but directly generates an audio signal; this loudspeaker comprises a body of a horn or cone to direct the audio signal.

In another embodiment, the power output of the directional loudspeaker is increased by increasing the transmission efficiency (e.g., demodulation or mixing efficiency). As described in "Possible development of nonlinear acoustics in underground transmission Applications" (H.O. Berktay, in J.Sound Via. Vol.2 (4): 435-461, 1965), the output audio power is proportional to the nonlinear coefficient of the mixing or demodulation medium (modulation medium) according to the formula for the estimation of Berktay.

As explained earlier, in one embodiment, a directional audio signal may be generated based on parametric acoustic techniques. Fig. 3 shows some examples of the mechanical structure principle of directing the ultrasonic signal. They represent different guiding methods, for example gratings, flexible wires or wedges (wedges) can be used.

Fig. 4A shows an embodiment of a directional loudspeaker 50 with a blazed grating. For example, speaker 50 is suitable for use as directional speaker 16. Each of the emitting devices, such as 52 and 54, of speaker 50 may be a piezoelectric device or other type of speaker disposed on a respective step. In one embodiment, the sum of all emitting surfaces of the individual emitting devices may be on the order of several wavelengths of the ultrasonic signal.

In another embodiment, each of the emitting devices may be driven by the exact same ultrasonic signal with appropriate delays to cause the emitted waves to interfere beneficially in the blazed normal direction 56, which is orthogonal to the grating. This is similar to beam steering (beam steering) operation of a phased array, which can be implemented by a delay matrix (delay matrix). This delay between adjacent emitting surfaces can be approximately expressed as h/c, where h is the height of each step of the grating. One way to simplify signal processing is to set the height of each grating step to be an integer multiple of the ultrasonic or carrier wavelength and all the emitting devices are driven by the same ultrasonic signal.

Based on the grating structure, the array direction of the virtual audio source is the blazed normal direction 56. In other words, such a stepped structure enables setting the propagation direction of the audio signal. In the example shown in fig. 4A, there are three emitters or speakers, one on each step. The total emission surface is the sum of the emission surfaces of the three devices. The propagation direction is approximately 45 degrees from the horizontal. The thickness of each speaker may be less than half the wavelength of the ultrasonic waves. If the frequency of the ultrasonic waves is 40kHz, the thickness may be about 4 millimeters.

Another way to direct the audio signal in a particular direction is to position a directional loudspeaker of the present invention at the end of a flexible wire. The user can bend the wire to adjust the direction of propagation of the audio signal. For example, if the speaker is placed on the user's shoulder, the user may bend the wire to direct the ultrasonic signal generated by the speaker toward the user's ear proximate the speaker.

There is another method of positioning the speaker device on a wedge. Fig. 4B shows an example of a wedge 75 with a loudspeaker 77. The angle of the wedge with the horizontal is about 40 degrees. This allows the direction of propagation 79 of the audio signal to be set at about 50 degrees from the horizontal.

In one embodiment, the ultrasonic signals are generated by a controllable phased array of individual devices, as exemplified with reference to FIG. 5. They produce directional signals through beneficial interference of the devices. The signal beam is steered by varying the relative phase between the arrays of devices.

One of the methods of changing the phase in one direction is to use a one-dimensional shift register array. The shift amount or delay amount of each register for the ultrasonic signal is the same. This array is capable of steering the beam by changing the clock frequency of the shift register. These shift registers are referred to as "x" shift registers. In order to be able to control the beams independently also in one orthogonal direction, one approach is to provide a second set of shift registers, which are controlled by a second variable frequency clock. This second set of registers, referred to as the "y" shift registers, is divided into a number of register subsets. Each subset may be an array of shift registers, each array being connected to an "x" shift register. By varying the frequency of the second variable frequency clock, the beam in the orthogonal direction can be steered.

For example, as shown in fig. 5, the acoustic phase array (acoustic phase array) is a 4 × 4 speaker device array. In this acoustic phase array, each device is identical. These devices may be, for example, 7 mm diameter emitter bimorph piezoelectric devices, or 7 mm diameter emitters. The overall size of this array may be around 2.8 cm by 2.8 cm. The carrier frequency may be set to 100 kHz. The driving power of each bimorph piezoelectric device is lower than 0.1W. The array is planar but each bimorph piezoelectric device is directed towards the ear of the user, for example, at an angle of 45 degrees to the normal to the array. The main lobe full width at half maximum (FWHM) of each individual bimorph piezoelectric device is about 0.5 radians or so.

There may be 4 "x" shift registers. Each "x" shift register can be connected to an array of 4 "y" shift registers, thereby creating a 4 x 4 shift register array. The clock operating frequency may be about 10MHz (each shifted by 100 nanoseconds). The ultrasonic signal may be transmitted in a digital format and delayed through a number of shift registers.

Assuming a distance from the ear to the array of about 20 cm, the coverage area around the ear of the main lobe of each device in the array is roughly 10 cm x 10 cm. Because the range of motion of the user's head may exceed 10 cm by 10 cm, the signal beam may be adjusted by approximately 0.5 radians in each direction. This is equivalent to a maximum relative time delay of 40 microseconds in one direction of the phased array, or 5 microseconds per device.

For an n x n array, the ultrasound beam from each array element interferes with other beams to produce a final beam having a beam width of only 1/n of the original beam. In the above example, where n is equal to 4, the beam shape of the phase array narrows to 1/4 in each direction. That is, the full width at half maximum (FWHM) is less than 8 degrees and the area around the ear that can be covered is about 2.8 cm × 2.8 cm.

Since the energy is concentrated in a small range, the power requirement is reduced to 1/n²And the power efficiency is greatly improved. In one embodiment, the array is capable of providing power in excess of 90dB SPL (sound pressure level).

In the above example, an array of piezoelectric thin film devices may be used instead of the bimorph piezoelectric devices.

In one embodiment, the interface unit may also include a pattern recognition device that can identify and locate the ear or ear canal (earcanal). In this way, the beam may be more accurately propagated toward the opening of the ear or ear canal if the ear or ear canal can be identified. Based on the closed-loop control, the propagation direction of the ultrasonic signal can be controlled according to the result of the pattern recognition method.

One method of pattern recognition is to determine the entrance of the ear canal from the thermal image. The thermal mapping may be achieved by an infrared sensor. Another pattern recognition method is based on a pulsed infrared LED and a roticon or CCD array for detection. The top of the reticulon or CCD array may be provided with a broadband interference filter, which may be a piece of coated glass, to filter the light waves.

Note that if the system is unable to identify the location of the ear or ear canal, the system may expand the cone's range or otherwise reduce its directionality. For example, all array elements can transmit the same ultrasound signal without delay, but at a reduced frequency.

Privacy is often one of the focus of attention of cell phone users. Unlike music or video players, users of these devices passively receive information or entertainment programming, and use cell phones with two-way communications. In most cases, the user of the mobile phone is already accustomed to the content of the conversation that others hear as part of himself. At a minimum, they can control or regulate their own portion of the communication. However, cell phone users generally do not want others to understand their entire conversation. Thus, for many applications, at least the voice output portion of the handset should provide a level of privacy. With the directional loudspeaker discussed herein, the audio signal is directional and the wireless communication system can provide some degree of privacy protection.

Fig. 6 shows an example of an interface unit 100 attached to a user's jacket. The interface unit 100 includes a directional speaker 104 and a microphone 106. This directional loudspeaker 104 emits an ultrasonic signal in a conventional direction towards the ear of the user. The ultrasonic signal is converted in the air between the speaker and the ear by mixing or demodulation. This directional ultrasonic signal confines most of the audio energy in a cone 108 directed toward the user's ear. When the cone 108 reaches the user's head, its surface area may be adjusted to be smaller than the user's head. In this way, directional ultrasonic signals can provide a degree of privacy protection.

In one embodiment, there are one or more additional speaker devices, either inside the directional speaker, proximate to the directional speaker, or surrounding the directional speaker. The user's head may scatter a portion of the received audio signal. Others in the vicinity of the user may be able to receive these disseminated signals. Additional speaker devices, such as piezoelectric devices, emit random signals that interfere with or destroy these scattered signals or other signals that may be emitted outside the cone 108 of directional signals to reduce the chance of interception of these scattered signals by others.

Fig. 7 illustrates the principle of the mechanism how the interface unit is attached to the user's clothing. For example, the interface element may be integrated within the user's garment, such as between an outer layer and an inner liner of the garment. The interface unit may have an electrical protrusion (protrusion) protruding from the inside of the garment in order to receive power or other information from the outside.

In another embodiment, instead of being integrated into a garment, the interface unit may be attached to the user's garment. For example, the user may attach the interface unit to his or her clothing and then turn on the device. Once secured, the interface unit may be hands-free. This interface unit may be attached to a belt of a garment, such as a shoulder strap of a jacket. Attachment may be by means of clips, pins or hooks. The interface unit may also be placed in a small pocket that is opened and closed by some mechanism (such as a button) in, for example, the clavicle area or shoulder area of the garment. In another example, the attachment may be accomplished by hook and loop fasteners (Velcro) on both the interface unit and the garment. The interface unit may also be attached by a resilient strap, such as a resilient arm strap. Alternatively, the interface unit may be hung around the user's neck with a chain, like a decorative necklace. In yet another embodiment, the interface unit may contain a magnetic object, and the clothing may contain a magnet that attracts the magnetic interface unit. It is noted that one or more of these means may be combined to ensure a more secure attachment. Yet another embodiment is one in which the interface unit is disposable. For example, once the energy is used up, the interface unit may be discarded.

As for the connection between the interface unit and the base unit, fig. 8 illustrates a number of different connection techniques. The interface unit may be connected to the base unit wirelessly or by wire. In wirelessly connected embodiments, the interface unit may be connected via bluetooth, WiFi, Ultra Wideband (UWB), or other wireless network/protocol.

Fig. 9 illustrates various additional attributes of the wireless communication system of the present invention. The system may include additional signal processing techniques. Typically, Single Sideband (SSB) or Lower Sideband (LSB) modulation, with or without compensation, can be accurate. If compensation is used, a processor (e.g., a digital signal processor) may be configured according to known techniques. Other elements or functions may also be integrated with the processor. This may be a local oscillation for up or down conversion and an impedance matching circuit. Echo cancellation techniques may also be included in the circuit. However, since the speaker is directional, echo cancellation circuitry may not be required. These additional functions may also be implemented in software (e.g., firmware or microcode) that is executed by a processor.

The base unit may have one or more antennas for communicating with a base station or other wireless devices. The additional antenna may improve the efficiency of the antenna. In instances where the interface unit is wirelessly connected to the base unit, an antenna on the base unit may also be used to communicate with the interface unit. In this case, the interface unit may have more than one antenna.

The antenna may be integrated into a garment. For example, the antenna and base unit may be integrated together into a garment, which may be located on the back of the garment.

The system may have a maximum power controller to control the amount of maximum power emitted from the interface unit. For example, the average output audio power may be set at around 60dB, with the maximum power controller limiting the maximum output power below 70 dB. In one embodiment, the maximum power is in the interface unit and is adjustable.

The wireless communication system may be voice activated. For example, a user may enter a telephone number using a voice command (voice command). Information, such as a telephone number, may also be entered into a separate computer and then downloaded to the communication system. The user may use voice commands to establish a connection with other telephones.

A wireless communication system may have an in-use display device (i.e., an "in-use") that indicates "in-use". For example, if a system, such as a mobile phone, is in operation, and if the user is talking on the phone, a light emitting diode may be used as a flashing light display at the interface unit. Such an "in use" display device enables others to know that the user is in the phone.

In yet another embodiment, the base unit of the wireless communication system may also be integrated into an article of clothing. The base unit may have a data port for exchanging information and a power plug for receiving power. Such one or more ports may protrude from the garment.

FIG. 10 illustrates various attributes of a power supply. The power source may be a rechargeable or non-rechargeable battery. For example, a bimorph piezoelectric device such as AT/R40-12P of Nicera/Nippon Ceramic, Japan, may be used as a speaker device for forming a speaker. It has an impedance of 1000 ohms and consumes power in the milliwatt range. A coin cell battery capable of storing hundreds of milliamp hours (mAHour) of energy has sufficient energy to power this unit for a limited long period of time. Other types of batteries may also be applied.

The power supply may use a dc power supply. The power source may be attachable or may be integrated or embedded in the clothing worn by the user. The power source may be a rechargeable battery. In one embodiment, a rechargeable battery is integrated into the garment with its charging port exposed. The user can recharge the battery on the way. For example, if the user is driving, he may use a lighter-type charger to recharge such batteries. In another embodiment, the power source is a fuel cell. The cell is flooded with a fuel, such as methanol.

There have been described embodiments in which the wireless communication system is a telephone, and in particular a handset capable of hands-free use. In one embodiment, the wireless communication system is envisioned as a hands-free mode telephone. Figure 11A shows an embodiment of a dual mode telephone. In a normal mode phone, the audio signal is generated directly through a speaker integrated with the phone (e.g., in the phone housing). Such a speaker is generally non-directional or does not generate audio signals by the transition of ultrasonic signals in air. In a dual mode phone, one mode is a hands free mode phone and the other mode is a normal mode phone, as described above.

The mode selection may be set by a switch on the phone. In one embodiment, the mode selection may be automatic. Fig. 11B illustrates a different technique for automatically selecting a dual mode telephone mode. For example, if the phone is attached to clothing, the directional speaker of the interface unit may be activated automatically, and the phone becomes a hands-free mode phone. In one embodiment, the automatic activation may be accomplished by a switch integrated into the phone. The switch may be a magnetically actuated switch. For example, when this interface unit is attached to clothing (hands-free use), a magnet or piece of magnetized material in the clothing may cause the phone to operate in a hands-free mode. The magnetically actuated switch may switch the telephone to the normal telephone mode when the telephone is removed from the garment. In another embodiment, this switch is mechanical. For example, once the interface unit is attached, mechanical activation may be performed using an on/off button on the unit. This may be achieved, for example, by a lever which is automatically depressed when the interface unit is attached. In another example, the initiation may be based on directionality. If the interface unit is substantially horizontal (e.g., within 30 degrees of horizontal), the phone will operate in a hands-free mode. Conversely, if the interface unit is approximately in a vertical orientation (e.g., within 45 degrees of the vertical), the phone will operate as a normal mode phone. A gyroscope may be used in the interface unit to determine the orientation of the interface unit.

There have been some embodiments described in relation to a wireless communication system being a telephone with a directional loudspeaker and a microphone. However, the present invention can be applied to other fields. Fig. 12 shows examples of other embodiments of the interface unit, and fig. 13 shows examples of various additional applications.

The interface unit may have two speakers, each directing the audio signal to one ear of the user. For example, one speaker may be placed on one shoulder of the user and another speaker on the other shoulder. In this way, the two loudspeakers can provide a stereo effect to the user.

There have been some descriptions of embodiments in which a microphone and a speaker are integrated together into a single package. In another embodiment, the microphone may be a separate element and may also be attached to the garment. For a wired connection, the leads from the base unit may be connected to a speaker, and at least one lead may be separate and connected to a microphone near the user's head.

The interface unit may not contain a microphone. Such a wireless communication system may be used as an audio unit, such as an MP3 player, a CD player or a radio. Such a wireless communication system may be considered a one-way communication system.

In another embodiment, the interface unit may be used as an audio output for some systems, such as a stereo system, a television, or a video game. For example, the user is playing a video game. Instead of emitting an audio signal with a common loudspeaker, the audio signal or a representation of the audio signal is transmitted in a wireless form to a base unit or interface unit. In this way, the user can hear the audio signal in a directional manner, thereby reducing the chance of interference with people in the user's surroundings.

In another embodiment, the base unit and the interface unit are integrated together and attached to the garment using the same techniques as described above for the interface unit.

In yet another embodiment, the interface unit may include a monitor or display. The user can watch TV or video programs in public places, and the interference to the surrounding environment can be reduced because the audio signals are directional. For wireless applications, the video signal may be transmitted from the base unit to the interface unit using UWB (ultra wide band) signals.

The base unit may also have the capabilities of a computing system, such as in a Personal Digital Assistant (PDA) or a laptop computer. For example, when a user performs various operations on a computing system, he can simultaneously communicate with another using the interface unit in a hands-free manner without having to leave the computing system. Data generated by a user running a software application on the computing system may be digitally transmitted to a remote device (e.g., another base station or unit) via voice signals. In this embodiment, the directional speaker need not be integrated or attached to the user's clothing, but may be integrated or attached to a computing system that may operate as a phone. The user may receive directional audio signals from the handset while still being able to operate the computing system with both hands. That is, the user may make a call and use the computing system simultaneously. In another aspect of this embodiment, the computing system can also be wirelessly connected to a local area network, such as a WiFi or WLAN network, through which high-speed data and voice communications can be achieved. For example, the user may make an IP call. In one embodiment, high speed data and voice communications allow signals to be transmitted wirelessly at frequencies in excess of 1 GHz.

In yet another embodiment, the wireless communication system may be a personalized wireless communication system. The audio signal may be personalized to the hearing characteristics of the system user. This personalization process can be done periodically, say once a year, similar to periodic recalibration. Such recalibration may be done by another device, the results of which may be stored in a memory. This memory may be a removable media card that can be inserted into the wireless communication system to personalize the amplification characteristics of the directional speaker as a function of frequency. The system may also include an equalizer to allow the user to personalize the amplitude of the speaker audio signal as a function of frequency.

The system may also be personalized based on the noise level of the user's surroundings. It may sense the noise level of the surrounding environment and vary the intensity of the audio signal as a function of the noise level.

The form factor of the interface unit can be quite compact. In one embodiment, the interface element is rectangular in shape. For example, it has a width of "x", a length of "2 x", and a height of less than "x". "X" may be 1.5 inches or less than 3 inches. In another example, the interface unit has a height of less than 1 inch. In yet another example, the interface element may not be flat, and it may be capable of bending to conform to the contour of the user's body.

Some embodiments have been described in relation to the loudspeaker being oriented. In one embodiment, a speaker may be considered directional if its full width at half maximum (FWHM) of the ultrasonic signal is less than about 1 radian or about 57 degrees. In another embodiment, a speaker may be considered directional if its full width at half maximum (FWHM) of the ultrasonic signal is less than about 30 degrees. In yet another embodiment, a speaker emits signals, such as from the shoulder of the user, or the speaker emits signals at the ear of the user; a speaker may be considered directional if the audio signal energy reaches 75% in less than 50 square inches of area near the user's ear or in the range of 6 to 8 inches of the speaker. In yet another embodiment, a speaker is considered directional if 75% of the speaker audio signal energy is concentrated in an area of less than 20 square inches near the ear or within a few inches, say 8 inches, of the speaker. In another embodiment, a speaker is considered directional if 75% of the speaker audio signal energy is concentrated in an area of less than 13 square inches near the ear or within a few inches of the speaker, say 8 inches.

Furthermore, referring back to FIG. 6, in one embodiment, a loudspeaker is considered to be a directional loudspeaker if most of the energy of the loudspeaker audio signal is traveling in one direction and the energy is confined to a virtual cone, such as the cone 108 in FIG. 6, the angle between the sides of the cone in FIG. 6, or the apex angle of the cone is less than 60 degrees. In another embodiment, the angle between the sides of the cone, or the apex angle of the cone, is less than 45 degrees.

In some embodiments described above, the ultrasonic signal frequency generated by the directional loudspeaker is within 40 kHz. One of the reasons for selecting this frequency band is to consider power efficiency. However, to reduce leakage and cross-talk or enhance privacy, in one embodiment, the ultrasonic signal has a frequency between 200kHz and 1MHz and is generated by a multilayer piezoelectric film or other type of solid state device. Since the carrier frequency is in the higher frequency range above 40kHz, the absorption/attenuation coefficient in air is higher. For example, in a certain calculation, the attenuation coefficient α at 500kHz may reach around 4.6, indicating that this ultrasonic wave will attenuate at exp (- α xz) or 40 dB/m. As a result, the ultrasonic wave is attenuated sharply, and the range of action of the speaker is reduced in the propagation direction of the ultrasonic wave. On the other hand, privacy is enhanced and audible interference to others is reduced.

Some embodiments are described with respect to directional loudspeakers in which the resulting propagation direction of the ultrasonic waves is not orthogonal to the horizontal direction, but at an angle of, for example, 45 degrees. These ultrasonic signals may be tilted so that the main beam of ultrasonic waves may be roughly directed at one ear of the user. In one embodiment, the propagation direction of the ultrasonic waves is approximately at right angles to the horizontal direction. So that the speaker need not be positioned on a wedge or a step. It may be located on a surface substantially parallel to the horizontal. For example, the speaker may be placed on the shoulder of the user, and the ultrasonic waves are propagated upward, rather than being obliquely directed, at the ear of the user. If the power of the ultrasonic waves is high enough, the power of the sound waves is sufficient even if the speaker is not directed exactly at the ear.

One explanation for this sufficiency in acoustic energy is that the ultrasonic speaker produces a virtual source in the direction of propagation. These virtual sources reproduce the second order acoustic signals not only along the direction of propagation, but in many directions. This is similar to the antenna mode, which scatters energy in many directions other than the direction of propagation. In one such embodiment, if: (a) the carrier frequency of the ultrasonic wave is 500 kHz; (b) the audio frequency is 1 kHz; (c) the size of the emitter of the loudspeaker is 3 cm multiplied by 3 cm; (d) transmitter power (peak) is 140dB SPL; (e) the transmitter is located 10 cm to 15 cm from the ear, such as on the shoulder of the user; (f) the ultrasonic beam is directed upwards, not towards the ear, and the center point of the ultrasonic beam is at a distance of about 2-5 cm from the ear. The acoustic energy was calculated to be 45 to 50dB SPL under the above conditions.

In one embodiment, an ultrasound beam is considered to propagate directly to the ear as long as the ultrasound beam or any portion of the beam cone is in close proximity to the ear, e.g., within 7 centimeters. The direction of the beam need not be directed directly towards the ear, it may even be perpendicular to the ear, say propagating from the shoulder of the user, substantially parallel to the face of the user.

Yet another embodiment, wherein the emitting surface of the ultrasonic speaker may not be flat. It can be designed to be concave or convex, which ultimately produces a divergent ultrasound beam. For example, if the focal length of the convex surface is f, the energy of the ultrasonic beam is attenuated by 6dB at the distance f from the emitting surface. For example, if f is equal to 5 cm, then outside 50 cm the ultrasonic signal will be attenuated to 20 dB.

There have been some descriptions of embodiments in which the device is attached to a garment worn by a user. In one embodiment, attached to the clothing worn by the user means worn by the user. For example, a user may hang a speaker around the neck, like a pendant on a necklace. This may also be considered to be otherwise attached to the clothing worn by the user. Or from another perspective, the necklace can be viewed as a "garment" worn by the user and the device can be attached to the necklace.

One or more of the embodiments described above may be combined. For example, two directional speakers may be placed one on each side of a notebook computer. When a user plays a game on a laptop, the user can use the microphone and directional speaker on the laptop to communicate with other players without having to remove the hands from the keyboard or the game console. Since this speaker is directional, the audio signal is mostly limited to be directed directly to the user in front of the laptop.

Hearing enhancement

Some embodiments of the present invention relate to hearing enhancement systems that enhance the hearing of individuals, particularly those with mild or moderate hearing impairment.

Fig. 14 shows an embodiment of a hearing enhancement system 2010 of the present invention. The hearing enhancement system 2010 includes an interface unit 2014 that includes a directional speaker 2016 and a microphone 2018. The embodiment may also include a base unit 2012 having or connected to a power source. The interface unit 2014 may be electrically connected to the base unit 2012. In one embodiment, the base unit 2012 may be integrated within the interface unit 2014. Such connection may be wired (e.g., via a cable) or wireless (e.g., via bluetooth technology).

Fig. 15 shows a person wearing the interface unit 2100 of the present invention on his jacket 2012. This interface unit 2100 may be, for example, the interface unit 2014 shown in fig. 14. Likewise, the interface unit 2100 includes a directional speaker 2104 and a microphone 2106. The speaker 2104 may be on a line of sight (line of sight) of one ear of the user.

Consider a situation in which a user is speaking with a friend. In one arrangement, the microphone 2106 captures the voice of the friend, i.e., the audio signal. A hearing enhancement system made in accordance with the present invention may modulate the ultrasonic signals with these audio signals. The directional speaker 2104 then transmits the modulated ultrasonic signal from the air toward the user's ear. These transmitted signals are demodulated in air to produce an audio output signal. Based on the ultrasonic transmission, the speaker 2104 generates a directional audio signal and transmits the signal in the shape of a cone (virtual cone) 108 into the user's ear. In another arrangement, the directional speaker 2104 includes a solid cone or horn-like corner that transmits the directional audio signal directly. In yet another arrangement, the audio signal emitted by the speaker may be steered towards the ear or ear canal, the location of which may be determined by some mechanism (e.g., pattern recognition). Some different embodiments regarding directional loudspeakers have been described in the foregoing of the present application.

Generally speaking, hearing in both ears is reduced together. In a sense, this is similar to the case we wear myopic glasses. It is rare to see one eye of a person who needs to wear glasses, while the other eye has 20/20 vision. Thus, there may be two interface units, one for the left ear and the other for the right ear. The unit for the left ear can be placed on the left shoulder and the unit for the right ear on the right shoulder. The two interface units may be electrically connected together or to a base unit. Further, such a connection may be wired or wireless. In another arrangement, the interface unit may be hung by the user in the chest as a pendant from a necklace. The audio output signal may be propagated to both ears.

In one embodiment, the system is designed to operate in a frequency range between 500Hz and 8 kHz. Typically, the degree of hearing loss varies from one audio frequency to another. For example, in english, the user may be able to easily hear the sound of a vowel, but consonants such as "S" and "P" are not easily heard. Fig. 16 shows different embodiments of the invention with respect to frequency response amplification of a received audio signal. It is noted that amplification is not limited to directly amplifying the received audio signal. For example, in one embodiment where an ultrasonic signal is used to generate an audio output signal, amplification may mean that the audio output signal is at a higher power level than the received audio signal. This can be achieved by increasing the power of the ultrasonic signal.

In one approach to frequency response amplification, it is assumed that hearing generally begins to decrease at high frequencies, such as 2 to 3 kHz. Then, hearing may require more assistance in the high frequency range. In this arrangement, the embodiment amplifies the audio signal so that around the entrance of the ear, between 2kHz and 4kHz, the signal reaches a Sound Pressure Level (SPL) of about 80 dB. The Sound Pressure Level (SPL) is low for frequencies below 2kHz, for example, the maximum SPL may be below 55dB if the frequency is below 500 Hz. In one embodiment, the SPL of the audio output signal is 70dB between 1.5kHz and 4kHz, with a 3dB cutoff point (3dB cutoff) also at 1.5 kHz. When the roll-off is 12dB/octave at 750Hz, the SPL becomes around 58 dB.

In another frequency dependent amplification scheme, it is assumed that most of the information in the audio signal is concentrated within a certain frequency band. For example, about 70% of the information in an audio signal may be concentrated in the frequency range of 1 to 2 kHz. Because the ear canal is open and the user may be only slightly or moderately impaired, the user may hear the audio signal directly from the speaker (e.g., without the assistance of a hearing enhancement system). In this scheme, the system filters audio signals within a certain frequency range (e.g., 1 to 2kHz) and processes them for amplification and transmission to the user. For the frequencies not in the frequency band, the user can directly obtain the frequency from the caller without processing and amplifying.

At low or intermediate frequencies, such as frequencies below 2kHz, the signal sound is generally loud. Since the hearing enhancement system does not require any hearing aid to be inserted in the ear, low or medium frequency signals can enter the ear unaltered. The mid-to high-frequency range (e.g., from 2000-3000 Hz) is the natural resonant frequency range of the ear canal, with typical values around 2700 Hz. Thus, these frequencies can be increased by about 15 dB. Since no hearing aid is inserted in the ear, the audio signal has no insertion loss, nor blocking effects caused by the user's own voice.

In a third approach, the amplification of the signal at each frequency is directly adjusted to meet the hearing requirements of the user. This can be done by calibration. This third aspect may also be combined with the first or second aspect.

Fig. 17 shows some embodiments relating to calibrating the hearing of a user at different frequencies. This calibration allows the system to determine (e.g., evaluate) the user's hearing sensitivity. By calibration, the hearing characteristics of the user can be known. The user can calibrate himself. For example, the audio frequencies are divided into different frequency bands. The system generates different Sound Pressure Levels (SPL) at each frequency band to test the user's hearing. The particular power level that the user feels most comfortable is the power level that is most suitable for him in that frequency band. After all frequency bands have been tested, the system may complete the establishment of the user's personal hearing characteristics based on the power level in each frequency band. During the calibration, the user can be prompted and guided by an interactive calibration process system.

In another embodiment, the calibration may also be performed remotely via a website. This website can give the user guidance throughout the calibration procedure. For example, the calibration task may be performed by a user sitting at a computer terminal connected to the website via the internet, the terminal having a speaker or headset to generate audio sounds as part of the calibration process.

The calibration process may also be performed for the user by a third party, say an audiologist.

The hearing characteristics of the user may be stored in the hearing enhancement system. If the calibration is done via a computer terminal, the hearing profile can be downloaded wirelessly (e.g., via Bluetooth or infrared technology) to the hearing enhancement system. Alternatively, the hearing profile can be stored in a portable media storage device, such as a memory stick. The memory stick may be inserted into a hearing enhancement system, or other audio producing device, that needs to receive hearing characteristics in order to personalize the amplification characteristics of the system by frequency.

The system may also periodically alert the user to recalibrate. Such as a period of one year. Calibration may also be done in stages, so that the task of performing a hearing assessment is less burdensome and less obvious.

Frequency dependent amplification has an additional advantage of saving energy, since some frequency bands may not require amplification or no amplification.

In one embodiment, the user can choose to change the system magnification manually. The system may also have a conventional volume control that allows the user to adjust the output power of the speaker. Such adjustments may also span certain frequency bands.

Since the ear canal is open, the user can hear audio signals from both the speaker and the system. In one embodiment, the signal processing speed of the system cannot be too low in order to prevent echo effects. Typically, the user will not be able to distinguish between two identical sets of audio signals if the two signals arrive with a time difference below a certain delay time, say 10 milliseconds. In one embodiment, the signal processing speed of the system is faster than the delay time mentioned above. One of the methods of converting these audio input signals into ultrasonic signals is through analog signal processing.

Power consumption is a problem because the system may be in operation for a long duration and amplified over a wide range of audio frequencies. FIG. 18A illustrates some embodiments relating to system power consumption management. One embodiment includes a manual on/off switch to allow the user to manually turn the system off when desired. This switch key may be on the base unit, on the interface unit, or on a remote control device. This switch key may also be activated by sound. For example, the system may be enabled to recognize specific recitations, such as certain sentences or phrases, and/or the user's voice. For example, the system automatically turns on when the user speaks a sentence similar to any of the following: what are you saying? What? Please be loud. What are you saying?

The system may be in an on-demand state. In one embodiment, the system is capable of identifying noise (such as background noise) as distinct from the audio signal with the information. For example, if the audio signal is flat over a wide range of audio frequencies, the system may assume that the audio input signal is noise. In another approach, if the average Sound Pressure Level (SPL) of the audio input signal is below a certain level, say 40dB, the system may consider that no audio signal is worth amplifying. When the system recognizes that the signal is not to be amplified, the system is not activated, but enters, for example, a sleep mode, a reduced power mode, or a standby mode.

Because the system has a choice to operate, the system goes into an inactive state when the talker stops speaking for a period of time. The duration of this time period can be varied in a regulated manner, for example 10 seconds or 10 minutes. In another arrangement, the system may be activated (i.e., awakened from a sleep mode, reduced power mode, or standby mode) only when the signal-to-noise ratio of the audio signal is greater than a predetermined threshold.

Another approach to power consumption management is to use a directional microphone. This scheme can improve the signal-to-noise ratio. Such a microphone can have a gain in a particular direction that is 20dB or more higher than an omni-directional (omni-directional) microphone. The direction of this directional microphone may vary depending on the application. In one embodiment, the directional microphone in front of the user may be oriented either forward or backward. Assuming that in general the user is facing a person talking to him, the audio signal emanating from that talking person in front of him is thus enhanced.

This system, i.e. the interface unit, may have more than one directional microphone, each pointing in a different direction. Fig. 19A shows an interface unit 2202 with 4 directional microphones pointing in 4 mutually orthogonal directions. If the user attaches the interface unit to a certain position on his clothes, the user may not have to consider the directionality of the microphones because the microphones are symmetrically arranged.

Fig. 19B-19C illustrate interface units 2204 and 2206, each having two directional microphones pointing in two mutually orthogonal directions, respectively. For the two interface units 2204 and 2206 shown in fig. 19B-19C, one can be placed on the left shoulder and the other on the right shoulder of the user with the user's head between the interface units of fig. 19B and 19C.

The amplification of the system may also be determined by the ambient power level, or the noise level of the system environment. One approach to measuring noise is to measure the average Sound Pressure Level (SPL) in pauses (gap) of the audio signal. For example, someone asks a question under the user, "do you leave your heart in san francisco? "generally, there is a pause between every two words or between every two sentences or phrases. For example, the system measures the root mean square (rms) value of the power for each pause, and may then average all of these rms values to determine the noise level. In one embodiment, the system increases the gain to ensure that the average power of the audio output signal is somewhat higher than the noise level. For example, the average SPL of the audio output signal may be 10dB higher than the noise level.

In another embodiment, if the average power level of the environment or the ambient noise level is above a certain threshold, the signal amplification will be reduced. Such ambient average power levels may include audio signals of the person talking to the user. The rationale is that if the environment is very noisy, it is difficult for the user to hear the audio signal from others. Therefore, the system should not amplify the audio signal regardless of the surrounding environment. For example, if the average power level of the environment is higher than 75dB, the amplification of the system is reduced to e.g. 0 dB.

Yet another power management scheme is to increase the power of the audio signal. One embodiment increases power by increasing the surface area of the medium responsible for generating the audio output signal. For example, if the audio signal is generated by a piezoelectric film, the power of the signal can be increased by increasing the surface area of the film.

Some embodiments are based on ultrasonic demodulation or mixing. For such embodiments, the output power may still be increased by increasing the surface area of the medium generating the ultrasonic signal. For example, a 1 cm diameter bimorph element (bimorph) can provide an ultrasonic SPL of 140 dB. The device may require approximately 0.1W of input power. 10 such devices can increase the output power by about 20 dB.

Another approach to increasing power is to have at least a portion of the conversion done in the medium rather than in the air, thereby increasing the efficiency of the demodulation or mixing of the ultrasonic signals. Depending on the medium, this may make the power efficiency of the directional loudspeaker higher. These schemes in this application have been described previously.

The system (interface unit and/or base unit) may include one or more rechargeable batteries (rechargeable batteries). These batteries can be recharged by connecting the system to a battery charger. Another feature that may be provided by the system is that it has one or more electrical connections to facilitate electrical connection to the battery charger. For example, when the power supply to the system is a rechargeable battery, the ability to recharge the battery directly without removing the battery from the system is advantageous. Thus, in one embodiment, the system includes at least one connector or conductive element (e.g., terminal, pin, pad, circuit board trace, etc.) for electrically connecting the rechargeable battery to the charger. At this point, electrical connectors or conductive elements are provided on the system that can be connected to the battery. The configuration of the electrical connectors or conductive elements on the system allows the system to be simply placed in a charger. Thus, the electrical connector or conductive element may make electrical contact with a mating electrical connector or conductive element in the charger.

Fig. 18B shows one embodiment of an interface unit 2150 having one electrical connection 2152 and one cover 2154. This interface unit 2150 may be the interface unit 2014 shown in fig. 14. Electrical connection 2152 may be a USB connector. When the cover 2154 is removed, the connection 2152 may be used, for example, to connect to a battery charger to charge the interface unit 2150.

In one embodiment, the charger may be considered a docking station (DockingStation) to which the system is connected to enable the batteries in the system to be charged. Thus, the system may likewise include an electrical connector or conductive element that, when placed on the base, facilitates electrical connection to the connection base.

Since the ear canal is open, the user can still use the phone directly. However, in one embodiment, the system containing the base unit may also have electronics that function as a cell phone. Fig. 20 illustrates such an embodiment. When a telephone call comes in, the system can change the working mode of the system and work as a mobile phone. The system may alert the user that a call is coming in, for example, via ringing, vibrating, or flashing lights. The user may make a call by, for example, pressing a certain key on the interface unit. The call-through can also be effected by an activation mechanism on the base unit or on the remote control device.

Fig. 21 is a flow diagram illustrating call processing 2400 according to one embodiment of the invention. The call processing flow 2400 may utilize the system, which may be the system shown in fig. 14, for example.

The first step of the call processing flow 2400 is a decision process (decision)2402 that determines whether or not a telephone call is incoming. When the judgment process 2402 judges that no telephone call is incoming, the call process 2400 continues to wait. Once the decision process 2402 determines that a telephone call is coming in, the system starts 2408. Here, the wireless communication capability of the system is enabled (e.g., powered on, enabled, or awakened). The user of the system is then notified 2410 that a telephone call is coming in. In one embodiment, the user may be notified of the incoming telephone call by an audio sound generated by the system (through a speaker). Alternatively, the user may be notified by vibration of the system, or by a visual display provided by the system (e.g., a light flash). Alternatively, the base unit may include a ringer device (ringer) that provides audio sounds and/or a vibration indication that displays incoming calls.

The second step is a decision process 2412 that determines whether the incoming call has been answered. When the determination 2412 determines that the incoming call has not been answered, the base unit may initiate 2414 a voice message informing the caller to leave a message or let the caller know that the recipient is not answering.

On the other hand, when the decision process 2412 determines that the incoming call is to be answered, then the call may be answered 2416 at the base unit. A wireless connection is then established 2418 between the interface unit and the base unit. The wireless connection may be, for example, a radio communication connection using a bluetooth or WiFi network. Communications information associated with the call may then be exchanged 2420 over the wireless connection. Here, the base unit receives an incoming call and wirelessly communicates with the interface unit, thus providing communication information to the user through the system. The system user is thus able to communicate with the caller via the system in a hands-free manner.

Next, decision process 2422 determines if the call has ended. If the determination process 2422 determines that the call has not ended, the call process 2400 returns to repeat 2420 operations and their subsequent operations to enable the call to continue. On the other hand, if the decision process 2422 determines that the call has ended, then the system moves to an inactive state 2424 and the radio connection and call are terminated 2426. The system entering the inactive state 2424 may place the system in a power reduction mode. For example, the inactive state 2424 may place system wireless communication capabilities (e.g., circuitry) in a power save, disabled, or dormant state. After operation 2426 and operations 2406 and 2414, call processing 2400 for a particular call ends.

If the system also operates as a telephone, the system may have a directional microphone directed towards the user's head. Fig. 19A shows such an embodiment.

Operating the system as a telephone may require different considerations than using the unit as a hearing enhancement system. Since the audio signal is transmitted in an open environment, a user may intercept a portion of the audio signal in the vicinity of the surrounding people. If the sound pressure level SPL is 80dB when the signal reaches the user's head, the signal reflected back from the head can reach 60 dB. Such a sound pressure level may be heard by people around the user. But the user may not want the person to hear what he is listening to. In other words, the user desires more privacy.

Fig. 22 shows some embodiments relating to improving the privacy of the present invention. The angle of propagation of the audio signal itself may improve privacy. The cone of audio signals is typically propagated from low to high in order to reach the user's ear. This angle of elevation may be 45 degrees, for example, from the user's shoulders to the user's ears. One of the advantages of such a direction of propagation is that most of the audio signal reflected from the user's head is propagated into the air above the head. This reduces the chance of the audio signal being overheard, especially when the signal power decays as the square of the propagation distance.

Privacy may be enhanced by frequency dependent amplification. Since some audio frequencies may not be amplified, their SPL may be quite low and their reflected signals may be extremely low. This reduces the likelihood that the entire audio signal will be heard by others.

Another approach to improving privacy is to reduce the maximum power level of the audio output signal below a certain threshold, say 70 dB. This number of levels may be sufficient to improve hearing in those with mild hearing impairment.

Yet another approach to enhance privacy is to further focus the beams of the audio signals. For embodiments based on switching the ultrasonic frequency, the cone may be narrowed by, for example, increasing the carrier frequency of the audio signal. Typically, the higher the carrier frequency, the narrower the cone, say a cone produced by a 100kHz signal is generally narrower than a cone produced by a 40kHz signal. Not only the cone will narrow, but the side lobes will also be suppressed. Another approach to narrowing the cone is to increase the gain of the cone or horn angle that produces the audio signal.

The focused beam has an additional advantage of better power saving. Since the audio signal is confined within a smaller cone, less power is required to generate the audio signal.

In private locations, such as home, hearing impaired people may sometimes prefer to turn the audio or video device too loud. On the other hand, in public places, hearing impaired people often have hearing difficulties. In one embodiment, the system is further designed to acquire, capture or access audio signals emitted by portable or non-portable devices, and the interface unit is used as a personalized hearing unit.

The audio signals emitted by these devices may be transmitted over wires (wires) connected to the system. The interface unit may provide an electrical input interface for connection to the device by a wire.

If the transmission is wireless, some electronics (e.g., WiFi or Bluetooth) may be included in the system design to capture the audio signals from these devices via a wireless evolving local area network. The audio signals from these devices may be up-converted (up-converted) to WiFi signals that are acquired by the system, which then down-converted (down-converted) to WiFi signals that reproduce the audio signals for the user to receive.

Fig. 23 shows other examples of such portable or non-portable devices. These devices may be used in a private environment, such as at home, or carried with the user. It may comprise an entertainment unit such as a television, stereo, CD player or radio. For example, assume that the user is working in a backyard and the stereo system is placed in the living room. Based on the above technology, the user can enjoy music without increasing the volume. Private personal use may include a telephone, which may be a desktop telephone with a conference speaker (conference speaker), or a cell phone. In another example, the system is used as a headset for a telephone, which may be connected to the telephone by wireless means (e.g., bluetooth).

As for use in public places, the user may be at a meeting or in a theater. The system may be wirelessly connected to a microphone of the conference or a loudspeaker of the theater so as to be able to capture and enhance the audio signals emitted there.

In some embodiments described above, the ultrasonic signal frequency generated by the directional loudspeaker is within 40 kHz. One of the reasons for selecting this frequency band is to consider power efficiency. However, to reduce leakage and cross-talk or enhance privacy, in one embodiment, the frequency of the ultrasonic signal is between 200kHz and 1MHz, and may be generated by multiple layers of piezoelectric film or other types of solid state devices. Since the carrier frequency is in the higher frequency range above 40kHz, the absorption/attenuation coefficient in air is higher. On the other hand, privacy is enhanced and audible interference to others is reduced.

Some embodiments are described with respect to directional loudspeakers in which the resulting propagation direction of the ultrasonic waves is not orthogonal to the horizontal direction, but at an angle of, for example, 45 degrees. The ultrasonic waves may be angled so that the main beam of ultrasonic waves may be roughly directed at one ear of the user. In one embodiment, the propagation direction of the ultrasonic waves is approximately at right angles to the horizontal direction. Such a speaker need not be positioned on a key or a step. It may be located on a surface substantially parallel to the horizontal. For example, the speaker may be placed on the shoulder of a user, and the ultrasonic waves are propagated upward, rather than obliquely, toward the user's ear. If the ultrasonic energy is sufficient, the signal waves have sufficient acoustic energy even if the speaker is not pointed accurately at the user's ear.

In one embodiment, an ultrasound beam is considered to propagate directly to the ear as long as any portion of the ultrasound beam, or cone of beams, is in close proximity to the ear, e.g., within 7 centimeters of the ear. The direction of the beam need not be directed directly towards the ear, it may even be perpendicular to the ear, say propagating from the shoulder of the user, substantially parallel to the face of the user.

Portable plug-in components (Add-On)

Some embodiments of the invention relate to directional speakers for portable electronic devices. This directional speaker may be used with the electronic device to direct audio output in a directionally limited manner. Thus, a user of the electronic device may obtain a certain degree of privacy with respect to the audio output without having to wear headphones or earphones, or without having to hold speakers against the ears. Such directional speakers may be integrated with the electronic device or may be an accessory (or peripheral) to the electronic device.

Such an electronic device may be a computing device, such as a personal computer, a laptop computer, or a personal palm top computer (PDA). It may also be a CD player, a portable radio, a communication device, or an electronic musical instrument such as an electronic piano. An example of a communication device is a mobile phone, such as a 2G, 2.5G or 3G phone.

Fig. 24A illustrates a mobile phone 3100 having an integrated directional speaker in accordance with one embodiment of the invention. Assuming that the mobile phone 3100 is a cellular phone, it includes a housing (housing)3102 for accommodating a main body of the mobile phone 3100. The mobile phone 3100 includes a display 3104, a plurality of keys 3106 for allowing a user to enter alphanumeric information or to make function requests, and a navigational control 3108 for the display 3104. To support wireless communications, the mobile phone 3100 also includes an antenna 3110. Further, the mobile phone includes a microphone 3112 for sound acquisition, and an ear speaker (ear speaker)3114 for audio output. The earbud speaker 3114 can also be considered as an earbud (ear plug).

In addition, the mobile phone 3100 may also include a directional speaker 3116 in accordance with the invention. This directional speaker 3116 provides directional audio sounds to the user of the mobile phone 3100. The user of the mobile phone 3100 is able to hear directional audio sounds produced by the directional speaker 3116 even if neither ear of the speaker is in close proximity to the mobile phone 3100. However, the directional nature of the directional sound output is towards the user, thus providing privacy by confining the audio sound to a limited directional area. In other words, the person next to the user is not within this limited directional area and cannot directly hear the audio sounds produced by directional speaker 3116. A person next to the user may be able to thus hear some of the audio reverberation reduced by the surface reflection. These reflected audio reverberation, if any, have a reduced decibel level (e.g., by at least 20dB) at the time of arrival, making it difficult for nearby people to hear those audio sounds.

Fig. 24B is a perspective view of a clamshell style mobile phone 3150 with an integrated directional speaker according to another embodiment of the present invention. Assume that the mobile phone 3150 is a mobile phone. The mobile phone 3150 shown in fig. 24B is similar to the mobile phone 3100 shown in fig. 24A. More particularly, the mobile phone 3150 includes a housing 3152 for housing the body of the mobile phone 3150. The mobile phone 3150 includes a display 3154, a number of keys 3156, and navigation controls 3158. To support wireless communications, the mobile telephone 3150 also includes an antenna 3160. In addition, the mobile phone 3150 includes a microphone 3162 for sound capture and an earmounted speaker 3164 for audio output.

Also, in accordance with the present invention, the mobile phone 3150 includes a directional speaker 3166. In this embodiment, the directional speaker 3166 is located in a lower region of the front cover portion of the chassis 3152 of the mobile phone 3150. This directional speaker 3166 directs audio output in a directional manner at the user of the mobile phone 3150. The directional nature of the directional sound output is towards the user, thus providing privacy by confining the audio sound to a limited directional area.

The direction of audio output of directional speakers 3116, 3166 may be estimated and thus fixed in advance. Thus, in one embodiment, directional speakers 3116, 3166 shown in fig. 24A and 24B may initially structurally fix their directional audio output. For example, angles and orientations may be set assuming that the user places the mobile phone 3100, 3150 in front of himself in order to view information on the display screen 3104, 3154 such that the directional speaker 3116, 3166 outputs audio in the direction of the user's ear.

In another embodiment, directional speakers 3116, 3166 may be movable in configuration so that the user can change the direction of the directional audio output as desired. Directional speakers 3116, 3166 may, for example, be reconfigurable to reconfigure the output direction of directional speakers 3116, 3166. Directional speakers 3116, 3166 may be repositioned, for example, by mounting on pivots, flex cables (flex wires), or other rotatable or flexible items.

In yet another embodiment, the mobile phone 3100, 3150 includes a knob or a switch to electrically control the direction of audio output. For example, assume that the keypad cluster on mobile phone 3150 shown in fig. 24B lies in the x-y plane, with the x direction approximately along the direction of the phone hinge (hinge). By rotating the knob, the user can adjust the output direction of the audio signal emitted by the directional speaker 3166 on the y-z plane.

In addition, the placement of directional speakers 3116, 3166 at cabinets 3102, 3152 may vary from implementation to implementation. However, in general, the placement is designed for the purpose of facilitating the direction of audio output to the person listening to these audio sounds. In summary, the placement of cabinet 3102 of directional speaker 3116 (shown in fig. 24A) and the placement of cabinet 3152 of directional speaker 3166 (shown in fig. 24B) are merely exemplary, and many other placement configurations are possible. For example, the directional speaker may be placed near the ear speaker, near the display screen, on the outside or back of the case, etc.

Fig. 25 is a perspective view of a personal palm computer 3200 having an integrated directional loudspeaker in accordance with one embodiment of the present invention. The personal palm computer 3200 includes a housing 3202 providing a body, an input pad 3206, navigation buttons 3208 and other buttons 3210. The display screen 3204 may display information for viewing by a user of the personal palm computer 3200. For example, the input interface 3206 may allow a user to select a soft key (soft button) or input characters through different gestures. Navigation keys 3208 allow a user to interact with information displayed on display screen 3204. The buttons 3210 may provide various functions such as initiating an operation, data entry, or item selection.

In addition, the personal palm computer 3200 includes a directional speaker 3212. The directional speaker 3212 provides a directional audio output to a user of the personal palm computer 3200. The audio output produced by directional speaker 3212 is not only directed in a predetermined direction, but is also substantially confined to the predetermined direction. Thus, the audio output of the directional speaker 3212 can be heard by the user of the personal palm computer 3200, but not readily heard by others.

The placement of directional speaker 3212 may be fixed or adjustable as shown in fig. 24A and 24B. If adjustable, the direction of the audio output can be changed. The placement of directional loudspeaker 3212 as shown in fig. 25 is but one possible embodiment; it should therefore be appreciated that the directional speaker 3212 may be located in many different locations on the personal palm computer 3200. But one option is that directional speaker 3212 is placed at the front of cabinet 3202.

The personal palm computer 3200 may or may not have wireless communication capabilities. However, if the personal palm computer 3200 has wireless communication capabilities, it may also include one or more microphones and conventional speakers. In another embodiment, the personal palm computer 3200 also includes a camera. If the personal palm computer 3200 has these elements, a user thereof may, for example, use the personal palm computer 3200 as a video phone or participate in a video conference using the personal palm computer 3200. The audio output produced by the personal palm computer 3200 may be directed primarily to its user by replacing the conventional speakers with directional speakers 3212. Thus, the audio output is private without the user having to hold the personal palm computer 3200 close to the ear or wear a headset. Therefore, the user of the personal palm computer 3200 can listen to the audio output in a relatively private manner while viewing the display 3204.

Fig. 26 shows a block diagram of a wireless communication device 3300 in accordance with an embodiment of the invention. More generally, the wireless communication device 3300 is a device having wireless communication capabilities. The wireless communication device 3300 may be, for example, the mobile phone 3100 shown in fig. 24A, the mobile phone 3150 shown in fig. 24B, or the personal palm computer 3200 (having such a circuit supporting wireless communication) shown in fig. 25.

The wireless communication device 3300 includes a controller 3302 that controls the overall operation of the wireless communication device 3300. The user input device 3304 may be one or more keys or a keyboard that enable a user to interact with the wireless communication device 3300. The display device 3306 may allow the controller 3302 to provide visual information to a user of the wireless communication device 3300. The controller 3302 is also coupled to Read Only Memory (ROM)3308 and Random Access Memory (RAM) 3310. The wireless communication device 3300 also includes a wireless communication interface 3312 for connecting the wireless communication device 3300 to a wireless link 3314 to enable information to be transferred between the wireless communication device 3300 and another communication device.

The wireless communication device 3300 also includes a microphone 3316 and a directional speaker 3318. The microphone 3316 may be designed to pick up an audio input signal coming from a particular direction. Directional speaker 3318 is specifically designed to output audio sounds in a limited direction. In one embodiment, the directional speaker 3318 outputs ultrasonic sound and converts it to an audio signal so that the user of the wireless communication device 3300 can hear the audio output. However, the audio output produced by the wireless communication device 3300 is difficult to hear by other people (beside the user) in the vicinity of the wireless communication device 3300 due to the use of the directional speaker 3318.

The wireless communication device 3300 can also include a conventional speaker 3320 and a camera 3322. The conventional speaker 3320 may be used when the user of the wireless communication device 3300 is not paying attention to privacy, but rather wishes others to hear the audio output, or when he places the device near one of his ears. The camera 3322 may allow the wireless communication device 3300 to transmit video (or at least still images) to other devices over the wireless link 3314.

As shown in fig. 26, a microphone 3316, directional speaker 3318, conventional speaker 3320, or camera 3322, is an accessory to the wireless communication device 3300 or is integrated on 3300. It should be appreciated, however, that any of the microphone 3316, directional speaker 3318, conventional speaker 3320, or camera 3322 may also be provided externally to the wireless communication device 3300, with a wired or wireless connection.

Fig. 27A is a block diagram of a directional audio conversion device 3400 in accordance with an embodiment of the present invention. The directional audio conversion device 3400 converts an audio input signal into a directional audio output signal. The directional audio conversion device 3400 includes a preprocessor 3402 and an ultrasonic speaker 3406. This preprocessor 3402 may be implemented by hardware or software. In one embodiment, at least a portion of the preprocessor 3402 may be internal to and form a part of the controller 3302 shown in FIG. 26. In another embodiment, the preprocessor 3402 may be a separate circuit, either internal or external to the wireless communication device 3300. This separate circuit may be an integrated circuit.

The ultrasonic speaker 3406 is one of directional speakers (e.g., directional speaker 3318). The preprocessor 3402 receives an audio input signal 3408 and converts it to an ultrasonic drive signal 3410. The ultrasonic drive signal 3410 is provided to an ultrasonic speaker 3406 to produce an ultrasonic output signal 3412. Ultrasonic output signal 3412 is then converted, for example, in air, to audio output signal 3414. It is generally desirable to have the spectrum of audio output 3414 as close as possible to audio input 3408.

In one embodiment, to mathematically represent the different operations of the audio transducer 3400, assume that its audio output is f (t) and the ultrasonic carrier signal is ω (t)_ct, drive signal f₁(t) the impulse response of the ultrasonic speaker or transducer is h (t), the ultrasonic output is g (t), and the audio output is y (t). Then ([ integral ] f (t) dt)²)^1/2*cosω_ct represents one embodiment of a pre-processing operation by a pre-processor to produce f₁(t) of (d). This may be considered as a basic pre-processing performed by the basic pre-processing circuitry. Furthermore, f₁(t) * h (t) represents the operations performed by the ultrasonic speaker to produce g (t), where symbol * represents the convolution of the signal. Finally, a²/*t²[g²(t)]Representing the ultrasonic output g (t) self-demodulated in air to produce an audio output y (t).

The preprocessor may further perform some additional operations to condition the drive signals 3410 before feeding them into the speaker. One of the goals of this additional pre-processing is to make the spectrum of audio output signal 3414 as similar as possible to the spectrum of audio input 3408.

Figure 27B is a block diagram of a preprocessor 3402 according to one embodiment of the present invention. In this embodiment, the preprocessor 3402 includes a basic preprocessing circuit 3450 and an evaluation circuit 3452. This estimation circuit 3452 is in a feedback loop formed by the basic pre-processing circuit 3450. In fig. 27B, D (t-f) represents the time delay f of the audio input 3408, which is also the total loop delay.

Fig. 27C shows one embodiment of the evaluation circuit 3452. In this example, H (t) represents the estimated impulse response of the ultrasound speaker, and G (t) represents the estimated ultrasound output, both of which are limited by the limited transmission bandwidth of the system. LPF1 and LPF2 represent low pass filter 1 and low pass filter 2, respectively.

The basic pre-processing circuit 3450 may have different embodiments. Let f (t) denote the audio input f (t) shifted by 90 degrees. For an amplitude modulated signal pre-processing scheme, various embodiments of the basic pre-processing circuit 3450 may perform any of the following operations:

(1+m*f(t))*cosω_ct, is suitable for large carrier double sidebands;

f(t)*cosω_ct, is suitable for double-sideband suppression carrier;

(1+m*f(t))*cosω_ct-m*F(t)*sinω_ct, is suitable for a large carrier single sideband;

f(t)*cosω_ct-F(t)*sinω_ct, is suitable for single sideband suppression carrier;

(1+m*f(t))^1/2*cosω_ct, suitable for modifying amplitude modulation;

(e(t)+m*f(t))^1/2/*cosω_ct, envelope modulation, where e (t) ═ LPF (f (t)), or f (t), is appropriate.

For a phase modulated signal pre-processing scheme, various embodiments of the basic pre-processing circuit 3450 may perform any of the following operations:

cosω_ct+cos(ω_ct+∫∫f(t)dt²) Is suitable for carrier phase modulation;

cos(ω_ct+∫∫f(t)dt²) And is suitable for inhibiting carrier phase modulation.

Fig. 28 illustrates different embodiments of directional loudspeaker characteristics according to the present invention. For example, the directional speaker may be any one of directional speakers 3116, 3166, 3212, 3318, and 3406 shown in fig. 24A, 24B, 25, 26, and 27A, respectively.

According to one embodiment, the directional loudspeaker may be implemented using a piezoelectric film. The piezoelectric film may be deposited on a plate consisting of a plurality of cylindrical tubes, for example, as in the previous examples. A substantial portion of the energy of the ultrasonic/audio output produced by the emitting surface of the directional loudspeaker may actually be confined to a cone (virtual or physical).

Referring back to the example of the piezoelectric film described above, the full width at half maximum FWHM of the signal beam may be about 24 degrees. It is assumed that the user holds such a directional loudspeaker, for example, held in his hand in front of him. The output produced by the speaker may be directed in a direction expected to be the head of the user, the distance between the hand and the head being about, say, 10 to 30 inches. More than 75% of the energy of the audio output produced by the emitting surface of the directional loudspeaker is in fact confined to a virtual cone. The top end of this cone is at the speaker and the opening is at the user's head. The diameter of the cone opening, or the diameter of the cone adjacent the user's circumference, may be about 4 to 12 inches.

In another embodiment, the ultrasonic frequency is 100kHz, with a convex surface to spread the beam, for example, as described below. The emission surface area of the directional loudspeaker is approximately 5 cm by 1 cm.

In one embodiment, the direction of audio output produced by the directional speaker is electrically adjustable. One solution is to attach the speaker to an electrically rotatable base. The orientation of the base may be set by turning a knob (e.g., on the phone 3150). In another embodiment, the speaker is composed of directional speakers. The phase between the signals generated by these directional loudspeakers can be adjusted to adjust the direction of the synthesized beam (residual beam). This is similar to the technique used to adjust the beam direction in phased array antennas.

In another embodiment, the directional loudspeaker may utilize a curved emitting surface (e.g., convex emitting surface) or a curved reflector. This curved emitting surface or mirror may allow the width of the beam to be increased.

Fig. 29 is a schematic flow diagram of audio signal processing 3600 according to one embodiment of the present invention. Here, it is assumed that the wireless communication device includes not only a directional speaker but also a conventional speaker (e.g., an ear speaker). The audio signal processing 3600 is performed, for example, by a wireless communication device. By way of example, the controller 3302 of the wireless communication device 3300 shown in fig. 26 can perform the audio signal processing 3600.

The wireless communication device may be a mobile telephone. Such a mobile telephone may have dual operating modes, i.e. a normal or conventional mode, a two-way or directional speaker mode. In the normal mode, the audio sounds are generated directly by a conventional (or typical) speaker, such as an earspeaker integrated in the chassis of the mobile phone. Such a speaker is substantially non-directional (and does not produce audible sound by converting ultrasonic signals in air). In the bi-directional mode, audio sounds are produced by a directional speaker. In the two-way mode, the mobile phone may be, for example, operated as a walkie-talkie, a communicator of the transmission type (dispatch type communicator), or a video phone.

The mobile phone may also have a speakerphone (speakerphone) mode in which audio output is produced by a speaker, allowing the audio output to be heard by people in the vicinity of the mobile phone. This speaker in this example is more powerful than the ear speaker, but is also substantially non-directional. Mode selection, whether manual or automatic, may be used to select the speakerphone mode.

Referring back to fig. 29, the audio signal processing 3600 first receives 3602 an audio input signal via a wireless communication path. Next, decision 3604 determines whether the directional speaker has been activated. When the decision 3604 determines that the directional speaker is not activated, then the audio input signal is output 3606 to the conventional speaker of the wireless communication device. When the wireless communication device is a mobile telephone, the conventional speaker is, for example, an ear speaker (earphone). On the other hand, when the wireless communication device is a personal palm computer or laptop, the conventional speaker may simply be a typical audio speaker.

On the other hand, when the decision 3604 determines that the directional speaker is activated, the audio input signal may be pre-processed 3608. Such pre-processing may employ the techniques described in fig. 27A-C, for example. After the audio input signal is pre-processed 3608, the pre-processed signal is converted 3610 to an ultrasonic drive signal. The directional loudspeaker is then driven 3612 in accordance with these ultrasonic drive signals.

Following steps 3606 and 3612, decision 3614 determines whether there are more audio input signals to pre-process at this time. When the decision 3614 determines that there are more audio input signals to be preprocessed, the audio signal processing 3600 returns to repeat the step 3602 and its subsequent steps so that other audio input signals can be preprocessed similarly. When decision 3614 determines that no more audio signals are being preprocessed at this time, the audio signal processing 3600 flow is complete and terminates.

In addition to steps 3604 and 3606 (which is not required when no speaker selection is possible), the directional audio conversion device 3400 illustrated in fig. 27A may also perform audio signal processing 3600.

Fig. 30 is a flow diagram illustrating a speaker selection process 3700, according to an embodiment of the invention. The speaker selection process 3700 may be performed by a wireless communication device. For example, the controller 3302 of the wireless communication device 3300 shown in fig. 26 may perform the speaker selection process 3700.

The first step of this speaker selection process 3700 is a decision 3702 that determines whether or not an artificial speaker selection has been made. When decision 3702 determines that an artificial speaker selection has been made, the selected speaker is activated 3704 upon an artificial request. The manual speaker selection may be accomplished, for example, by the user through a variety of methods, such as, for example, (a) a key on the device, (b) a user selection based on a user interface on the display screen, (c) a sensor meeting a particular sensed condition, or (d) other methods.

On the other hand, when the decision 3702 decides that no artificial speaker selection is made, device status information is obtained 3706. Such device status information may be obtained via one or more sensors integrated or connected to the device. Then, an appropriate speaker is selected based on the device state information decision 3708. For example, if the wireless communication device is placed near the user's ear, the sensor may detect (e.g., estimate) its position and choose to use a headset-type speaker accordingly. On the other hand, if the device is determined (e.g., estimated) to be at least a distance away from an object (e.g., a user's head or ear), then a directional speaker may be employed. In summary, the appropriate speaker is activated 3710. After steps 3704 or 3710, the selection process 3700 completes the termination.

The schematic diagram of fig. 31 lists some typical conditions that may be used to select an appropriate speaker. The speaker selection process 3700 and the exemplary conditions shown in fig. 31 assume that the wireless communication device has multiple speakers available for selection, at least one of which is a directional speaker and at least one of which is a conventional speaker.

Assume again that the wireless communication device is a mobile telephone. The mode selection between the normal mode or the conventional mode and the bi-directional or directional speaker may be done manually or automatically. Fig. 31 shows some examples of different techniques for implementing the mobile phone mode selection. In one embodiment, mode selection may be performed by a switch integrated into the mobile phone. This switch may be electronic, mechanical or electromechanical. For example, a mechanical switch may be located just beside a conventional speaker. When this conventional speaker is pressed against the user's ear, the switch is depressed and the conventional speaker is activated.

In another example, mode selection may be based on distance. The mobile phone may include a sensor that senses the distance of the mobile phone (e.g., its ear speaker area) from a surface. For example, the sensor may sense the distance using a light beam (e.g., an infrared beam). When this distance is very short, the normal mode is automatically selected; when this distance is relatively large, the mobile phone is considered not to be against the user's ear, and the two-way mode is automatically selected. One method of detecting distance with an infrared beam is to measure the intensity of the reflected beam. If the reflecting surface is very close to the infrared source, the intensity of the reflected beam will be high. However, if the reflecting surface is 12 "or more away, the intensity of the reflected beam will be much lower. Thus, by measuring the intensity of the reflected beam, the distance can be inferred.

In yet another embodiment, mode selection may also be made based on direction. If the mobile phone is positioned in a substantially vertical orientation (e.g., within 45 degrees of vertical), the mobile phone will operate in a two-way mode. However, if the mobile phone is located approximately horizontally (say, within 30 degrees of horizontal), the mobile phone will operate in the normal mode. A gyroscope in the mobile phone may be used to determine the orientation of the mobile phone. In another example, mode selection may be based on the method of use. For example, if the mobile phone is operating as a video phone, or playing a video program, by receiving input through its integral keypad, the mode of operation of the mobile phone may be set to a two-way mode.

In accordance with another embodiment of the present invention, FIG. 32A is a perspective view of a personal palm computer 3900. The personal palm computer 3900 is substantially similar to the personal palm computer 3200 shown in figure 25. However, the personal palm computer 3900 additionally includes a card 3902 that is inserted into a card slot of the device.

The card 3902 is a plug-in card that provides wireless communication capabilities as well as audio and video capabilities for the personal digital assistant 3900. More particularly, the card 3902 includes a directional speaker 3904, a camera 3906, a microphone 3908, and an antenna 3910. The directional speaker 3904 provides limited audio output in a particular direction, as mentioned in other embodiments above. The camera 3906 provides video input capabilities for the personal palm computer 3900. Microphone 3908 provides for audio input. The antenna 3910 is used for wireless communication. Thus, the card 3902 enables the personal digital assistant 3900 to operate as a video phone or participate in a video conference, otherwise the personal digital assistant 3900 cannot support wireless communications or audio-video capabilities. In this regard, the microphone 3908 can capture the user's audio output (sound), while the camera 3906 can capture the user's face or other desired images or video. The user of the personal palm computer 3900 can therefore hear incoming audio signals via the directional speaker 3904, which directional speaker 3904 provides a degree of privacy to the user by its directional nature. In addition, video input may be displayed on the display screen 3204 for easy viewing by the user.

Card 3902 may include a circuit within its body to support the functionality provided by card 3902. The circuit may be associated with various discrete electronic devices and/or integrated circuits. Thus, this circuit can supplement the circuitry of the personal palm computer 3900.

Although card 3902 includes wireless communication capabilities, including a microphone, a directional speaker and a camera, it should be understood that other cards used in a similar manner need not support each of the functions described above. For example, in one embodiment, such a plug-in card may simply be associated with only directional speaker 3904 and its associated circuitry (e.g., an audio transducing device).

Fig. 32B is a perspective view of a personal palm computer 3920 in accordance with another embodiment of the invention. The personal palm computer 3920 is also substantially similar to the personal palm computer 3200 shown in fig. 25. However, the personal palm computer 3920 further includes a card 3922 inserted into a card slot of the device.

Card 3922 is a plug-in card that provides directional audio functionality for personal palm computer 3920. Card 3922 includes a directional speaker 3904. The directional speaker 3904 provides limited audio output in a particular direction, as mentioned in other embodiments above. The personal palm computer 3920 may or may not support various other communication capabilities, such as audio or video input, wireless voice communication, and wireless data transmission. Card 3922 may contain a circuit within its body to support directional speaker 3924. The circuit may be associated with various discrete electronic devices and/or integrated circuits. This circuitry may thus supplement the circuitry of the personal palm computer 3900. Alternatively, the card 3922 may rely heavily on circuitry within the personal palm computer 3920.

Cards 3902, 3922 may also have different profiles (forms). In one example, CARDs 3902, 3922 are rectangular CARDs, typically PC-CARD or PCMCIA CARDs. In another example, the CARDs 3902, 3922 are smaller in size than PC-CARD or PCMCIA CARDs, such as a mini CARD. As another example, cards 3902, 3922 are a peripheral device that plugs directly into a peripheral port (e.g., a USB or Fire Wire interface) or is connected to a personal palm computer via wires (as shown in fig. 33).

Fig. 33 is a perspective view of the mobile phone 4000 and the peripheral accessory 4002. The mobile phone 4000 includes a microphone 4004 and an ear speaker 4006. The peripheral device 4002 is a plug-in to the mobile phone 4000 to enable the user of the mobile phone 4000 to perform external speaker arrangement. More particularly, this peripheral attachment 4002 includes a base 4008 that supports and positions directional speaker 4010. The directional speaker 4010 has a characteristic as described above, that is, a directionally limited audio sound output. Base 4008 supports directional speaker 4010. By repositioning the base 4008, the particular direction of limited audio output may be changed. The direction of audio output may also be adjusted electronically by the techniques described above.

Base 4008 is also connected to wires 4012, which has a connector 4014. The connector 4014 can be inserted into a receptacle (receptacle)4016 of the mobile phone 4000. In one example, socket 4016 can be or be a headphone jack or an external speaker socket associated with mobile phone 4000. The housing 4008 contains electronics to convert common audio signals that are to be transmitted to the housing 4008 via the jack 4016 of the mobile phone 4000. Then, an electronic circuit (e.g., a preprocessing circuit in fig. 27A) converts the audio signal into an ultrasonic drive signal to be used for driving the directional speaker 4010. The power required by the circuitry within the base 4008 may be supplied by a battery or by connection to a power source. The connection may be to a separate power source or to a power source together with the mobile phone 4000. This connection may be made through wire 4012 or other wire. In another example, the socket 4016 can be a peripheral port (e.g., Universal Serial Bus (USB), Fire Wire, etc.). If this port provides both data and power, the electronics in the base 4008 can be powered via the wires of the peripheral port. In addition, such a port may transmit data signals to base 4008 to generate drive signals for directional speaker 4010. In other words, at least a part of the pre-processing steps may be performed by the mobile phone 4000. In such an embodiment, the number of electronics required in base 4008 may be less than in other embodiments, as electronic functions (e.g., circuitry) in mobile phone 4000 may be used to perform some of the operational steps required to operate directional speaker 4010 in peripheral accessory 4002.

FIG. 34 is a schematic diagram depicting additional applications associated with the present invention.

Some embodiments have been described in relation to the portable electronic device with directional loudspeakers being a mobile phone. However, the invention is also applicable to various other applications, some examples of which are shown in FIG. 34. These various embodiments may be used alone or in combination.

In one embodiment, the device may be an audio unit, such as an MP3 player, a CD player, or a radio. Such a system may be considered a one-way communication system.

In another embodiment, the device may be an audio output device, such as for a stereo system, a television, or a video game console. In this embodiment, the device may also not be portable. For example, a user may be playing a video game and, instead of emitting audio signals from a common speaker, send the audio signals or representations of the audio signals to a directional speaker. In this way, the user can listen to these audio signals in a directional manner, thereby reducing the chance of interference with others in the user's surroundings.

In another embodiment, the device may, for example, be used as a hearing aid. Different embodiments have been described in this application with respect to enhancing hearing by personalizing or adjusting to the hearing of the user.

In one embodiment, the wireless communication device may operate as both a hearing aid and a cell phone. When no phone call comes in, the system is a hearing aid. On the other hand, when a telephone call comes in, the system transmits the incoming call to the user through the directional speaker without receiving its surrounding audio signals.

In yet another embodiment, the device may comprise a monitor or display. Users can watch television or video programs in public places with reduced possibility of disturbing surrounding people due to the directional nature of these audio signals.

The device may also have the functionality of a computing system, such as in a personal palm computer (PDA) or a notebook computer. For example, when a user is running multiple tasks on a computing system, he may communicate with another person in a hands-free manner at the same time. Data generated by a user running a software application using the computing system may be digitally transmitted to a remote device along with the voice signal.

In another embodiment, the device may be a personalized system. The system is capable of selectively amplifying different audio frequencies to different degrees depending on the user's preference or the user's hearing characteristics. In other words, the audio signal may be adapted to the hearing of the user. This personalization process can be done periodically, say once a year, similar to a recalibration. Such recalibration may be done by another device, the results of which may be stored in a memory. This memory may be a removable media card that can be inserted into the system to personalize the amplification characteristics of the directional speaker as a function of frequency. The system may also include an equalizer to allow the user to personalize the amplitude of the speaker audio signal as a function of frequency.

The device may also be personalized based on the noise level or sound level of the user's surroundings. It may sense the noise level or sound level of the surrounding environment and vary the amplitude characteristics of the audio signal as a function of the noise level or sound level.

Some embodiments have been described in which the loudspeakers are directional. In one embodiment, a speaker is considered directional if it is driven by an ultrasonic signal. Such a directional loudspeaker may also be regarded as an ultrasonic loudspeaker. Generally, such an ultrasonic speaker generates an ultrasonic output, and then is converted into an audio output by mixing in the air. For example, an ultrasonic output is generated by modulating an ultrasonic carrier with an audio output, and then the ultrasonic output is self-demodulated by nonlinear mixing in a space, thereby generating an audio signal.

The device may also be adapted for use in a mobile vehicle such as an automobile, a ship or an airplane. Furthermore, the directional audio conversion means may be integrated into or attached to the moving vehicle. This moving vehicle may be a car, for example. On the front panel or dashboard of the vehicle, there may be a USB, PCMCIA or other type of interface. The directional audio conversion device may be plugged into this interface to generate a directional audio signal.

In another embodiment, one or more directional speakers are integrated into a moving vehicle. These speakers may be used in a wide variety of applications for the vehicle, such as personal entertainment and communication applications.

In one embodiment, the directional loudspeaker emits an ultrasonic beam. The ultrasound beam may have a frequency within, for example, about 40kHz, and the beam may be divergent. For example, an ultrasound beam generated by a transmitter having a diameter of 3 cm diverges into a cone having a diameter of 30 cm after propagating a distance of 20 to 40 cm. If the diameter of the beam is increased by 10dB, the intensity of the ultrasonic wave is reduced by about 20 dB. In another embodiment, the ultrasound beam has a frequency in a higher range, such as in the range of 200kHz to 500kHz or so. Such higher frequency ultrasound beams attenuate more rapidly in the air, for example at an attenuation rate of 8 to 40dB/m, depending on the video rate. In yet another embodiment, the ultrasonic frequency of the beam is higher, such as 500kHz, and is also a diverging beam. This embodiment with higher frequencies and diverging beams is also suitable for other applications, such as applications where the propagation distance between the speaker and the ear is very short (e.g. 20 cm).

As regards the location of the loudspeaker, it may be mounted directly above the user in the vehicle, for example on the roof (rootop) above the seat. The speakers may be located slightly further from the front of the seat and closer to the rear of the seat, since a person typically rests on the seat back when seated. In another embodiment, the directional speaker is mounted slightly farther away, such as at a dome light (dome light), so that the ultrasonic beam is directed approximately at the headrest of the occupant seat in the vehicle. For example, if a speaker is placed at the corner of the roof light near the driver, the signal is directed approximately near the driver's head. Those signals that are not received directly by the intended recipient (e.g., driver) may be scattered by the driver and/or the seat structure, and the strength of the reflected signals received by other passengers in the vehicle is thereby reduced.

In one embodiment, the speaker may emit an audio beam instead of an ultrasonic signal, the directivity of which is determined by the physical structure of the speaker. For example, the speaker may be a horn or cone or other similar structure. The directivity of such a loudspeaker depends on the aperture size of its structure. For example, a 10 cm horn may have a λ/D value of about 1 at 3kHz and a λ/D value of about 0.3 at 10 kHz. Thus, at low frequencies, the directionality provided by such acoustic speakers is rather poor. And the intensity of the beam is 1/R²Where R represents a measured distance, such as to the apex of the horn. To obtain isolation, proximity becomes especially important. In such an embodiment, the speaker is located in close proximity to the user. It is assumed that the speaker is placed directly behind the passenger's ear, say at a distance of about 10 to 15 cm. The speaker may be placed at the headrest or headrest of the user's seat. Alternatively, the speaker may be placed in the user's seat with the beam directed at the user. If the other passengers in the vehicle are at least 1 meter away from the occupant, the sound isolation effect (isolationeffect) is about 16 to 20dB, depending on the propagation attenuation (or attenuation of the signal as it propagates through the air). The configuration of the horn or cone may provide additionalAn isolation effect, e.g. 6 to 10dB more.

In one embodiment, a user may control one or more characteristics of the beam. For example, the user may control the power, direction, distance, or range of action (coverage) of the beam.

As regards the position of these control means, it may be located on the dashboard of the car if the vehicle is a car. In another embodiment, the control device is on an armrest of a user seated seat.

These control means may be mechanical. For example, the speaker is located at the dome light, and a rotatable mechanism may be located in the dome light area. This rotatable mechanism allows the user to adjust the direction of the beam as desired. In one embodiment, the rotatable mechanism is rotatable in two dimensions. For example, the beam is emitted at an angle of 30 degrees to the roof of the vehicle, and the rotatable mechanism allows 180 degrees rotation of the beam around the front of the vehicle. In another embodiment, the elevation angle may also be adjustable, such as within a range of 20 to 70 degrees (at an angle to the roof).

Another mechanical control may be used to turn off the speaker. For example, the speaker will automatically turn off after the user leaves the seat for more than a predetermined time (e.g., 3 seconds).

The control device may also be mounted in a remote control. This remote control may utilize bluetooth, WiFi, ultrasound, infrared or other wireless technology. The remote control may also include a fixed or removable display. The remote control may be a portable device.

The sound level does not have to be too high, taking into account other characteristics of the beam, such as the power level of the signal. For example, the sound level may be about 60dB SPL at 5 centimeters from the speaker.

The signal content transmitted by the loudspeakers can be obtained in a number of ways. In one embodiment, the content may be from a radio station, received wirelessly by a speaker. For example, the content may be received over the internet, a WiFi network, a WiMax network, a cellular network, or other type of network.

The speaker does not have to receive program content directly from a broadcaster or information source. In one embodiment, the vehicle receives content wirelessly from an information source and transmits the content to the speakers via a wired or wireless connection.

In another embodiment, the content may be selected from a multimedia player of the automobile, such as a CD player. This multimedia player can receive content from multiple channels to support multiple users in the car. In addition, the received content or channel may be from a broadcast station and selected locally. Alternatively, the content may be interactively selected and delivered to the user via a wireless server station (wireless server station). In yet another embodiment, the content may be downloaded to the multimedia player entirely from a high-speed wireless network prior to playback.

Another type of control is the selection of a radio station or a piece of music on a multimedia player. Furthermore, these types of selection controls may be located in a fixed location in the vehicle, such as the dashboard, console, armrest, door, or seat of the vehicle to which the control knobs are mounted. Alternatively, as in another example, the selection controller may be a portable device.

Some embodiments have been described with respect to the use of a loudspeaker. In another embodiment, the user may use more than one speaker. The plurality of speakers may create a stereo or surround sound effect (surround sound effect).

As described above with respect to the multimedia player, it can receive signals from multiple channels to support multiple users in a vehicle. If there is more than one user in the vehicle, each user may have one or a set of directional speakers. As for the locations of these speakers for multiple users, in one embodiment, they are centralized. For example, all speakers are located at the ceiling lights of an automobile. Each user has a corresponding set of directional beams that propagate from the roof to the user. Alternatively, the speakers may be mounted in a distributed manner. For example, a speaker is mounted at the roof above each user's seat or at the user's headrest (headrest). As for the control, each user can independently control the signals transmitted to him. For example, a user's controller may control the user's own set of beams, or select content that he or she wishes to hear. Each user may have a remote control. In another embodiment, the user's controls are located in the user's armrest, seat, or near his door.

Set-top box

Some embodiments of the invention pertain to a directional audio transmission device for an audio system. The audio system may be a stereo system, DVD player, CD player, music amplifier or instrument, VCR, television, home entertainment system, or other audio system. Generally, it transmits an audio output based on or in relation to a certain audio signal. The audio signals may be generated by the audio system or transmitted to and received by the audio system. Such reception may be performed in a wireless or wired manner (e.g., via a wire). Without directional audio transmission devices, audio sounds produced by an audio system can be heard by people around it. The directional audio transmitting device converts the audio signal into a directional audio output which is mainly confined in a beam having a certain beamwidth. The targeted objects of the directional audio output are one or more people willing to listen to the audio output. In one embodiment, the target objects may also control some properties of the beam. Those who are nearby who are unwilling to hear the audio output hear only the lower signal. Therefore, they are less disturbed by these audio sounds that they do not need.

An audio system with a corresponding directional audio transmission device may be considered one directional audio device. The directional device may be incorporated into an audio system or be confined to a separate body, such as a set-top box. The set-top box may be connected to the audio system either by wire or wirelessly. In this embodiment, if the corresponding audio signal is not generated by the audio system but received from the outside, the audio signal may be received through both the set-top box and the audio system.

Fig. 35 is a block diagram of a directional audio device 5100 having an audio system 5102 and a directional audio transmitting device 5104, according to an embodiment of the present invention.

Fig. 36A is a block diagram of a directional audio transmission apparatus 5200 according to an embodiment of the present invention. The directional audio transmission device 5200 is suitable for use, for example, in a directional audio transmission device 5104 shown in fig. 35.

The directional audio transmission device 5200 includes an audio conversion circuit 5202 and a directional speaker 5204. This audio conversion circuit 5202 is used to receive audio signals (audio inputs), either from the audio system 5102 or from other devices. The audio signal may be, for example, an electronic signal from the audio system 5102, or an audio wave that is wirelessly transmitted to and received by the audio conversion circuit. The received audio signal may be pre-processed before being converted to an ultrasonic signal for directional speaker 5204. In one embodiment, directional speaker 5204 is an ultrasonic speaker that produces ultrasonic output to generate audio output. With this ultrasonic output as a carrier wave, the audio output is transmitted in a direction-limited manner (directionally-constrained controller). Thus, directional speaker 5204 allows audio output to be directionally limited and routed to a desired area.

Fig. 36B is a block diagram of a directional audio transmission device 5200 in accordance with another embodiment of the present invention. The directional audio transmission device 5200 is suitable for use, for example, in a directional audio transmission device 5104 illustrated in fig. 35.

The directional audio transmission device 5200 includes an audio conversion circuit 5222, a beam attribute control unit 5244 and a directional speaker 5226. The audio conversion circuit 5222 functions to convert the received audio signal into an ultrasonic signal. The beam property control unit 5244 controls one or more properties of the audio output.

One of the properties may be a beam direction. The beam property control unit 5224 receives a beam property input, which in this example is related to the beam direction and may be referred to as a direction input. This directional input provides information to the beam property control unit 5224 regarding the direction of propagation of the ultrasonic output produced by the directional speaker 5226. This directional input may also be a position reference, such as the position of the directional speaker 5226 (relative to its housing), the position of a person wishing to hear the audio sound, or the position of an external electronic device (e.g., a remote control). Thus, the beam property control unit 5224 receives the directional input and determines the direction of the audio output.

Another attribute may be the distance that the beam needs to travel. This may be referred to as distance input. In one embodiment, the ultrasonic frequency of the ultrasonic output may be adjusted. By controlling the ultrasonic frequency, the beam propagation distance can be adjusted as desired. This will be further explained below. Thus, with the appropriate control signals, the directional speaker 5226 produces the desired audio output.

Fig. 37A is a schematic diagram illustrating an exemplary arrangement 5300 suitable for use with the present invention. The exemplary arrangement 5300 uses a directional audio device 5302 to transmit audio output, which may be an ultrasonic cone 5304 (or beam) of ultrasonic output directed toward a first user (user 1). The directional audio device 5302 may utilize any directional audio transmitting means, such as directional audio device 5100. Note that in this exemplary apparatus 5300, a second user (user 2) and a third user (user 3) are also in the vicinity of the directional audio device 5302. However, in this example, it is assumed that only the first user (and not the second and third users) wishes to hear the audio sound. As a result, the directional audio device 5302 produces ultrasonic output in a directionally limited manner, such as with its cone 5304 (or beam) directed toward the first user (user 1). After the ultrasonic output is mixed or demodulated in air, the resulting audio sound (residual audio sound) is transmitted to the first user (user 1). Only significantly lower audio sounds are received by the second user (user 2) and the third user (user 3). Thus, they are not disturbed by the audio sounds heard by the first user.

Another way to control the audio output level received by other users is to use distance input. By controlling the distance of travel of the ultrasonic output, the directional audio transmission device 5302 can reduce the audio output that may be transmitted to others located (i) behind the first user (user 1), not shown in this figure, or (ii) located so as to receive audio output reflected from a surface behind the first user (user 1).

Fig. 37B illustrates a typical structural layout plan (buildinglayout)5320 of an application of the present invention. This exemplary structural layout plan view 5320 illustrates how a directional audio device 5328 according to the present invention may be used. The exemplary floor plan 5320 includes a first room 5322, a second room 5324 and a third room 5326. The first room 5322 may be, for example, a family living room. It is equipped with a directional audio device 5328. The first user (u-1), the second user (u-2), and the third user (u-3) are all in a first room 5322. The directional audio device 5328 may transmit audio sounds in a directionally limited manner. The directional audio device 5302 may utilize any of the directional audio transmitting devices of the present invention, such as the directional audio device 5100.

As shown in FIG. 37B, directional audio device 5328 sends the audio output or audio sounds in a controlled cone 5330 (beam) to the first user (u-1). Note that the audio output is primarily confined to cone 5330. Thus, the second user (u-2) and the third user (u-3) do not significantly hear the audio output produced by the directional audio device 5328. Portions of the sound from cone 5330 may be reflected or scattered by the rear surface and thus received by the second and third users. If so, the sound has attenuated to a lower level. In one embodiment, the distance of coverage of the cone 5330 of sound can be adjusted.

Fig. 38 is a flowchart of directional audio transmission processing 5400 according to one embodiment of the invention. The directional audio transmission processing 5400 is, for example, performed by a directional audio transmitter like the directional audio transmitter 5104 shown in fig. 35. More particularly, this directional audio transmission processing 5400 is particularly suitable for the directional audio transmission device 5220 illustrated in fig. 36B.

The directional audio transmission processing 5400 first receives 5402 an audio signal used for directional transmission. The audio signal may be provided by an audio system. Further, a beam property input is received 5404. It has been noted previously that the beam attribute input is one of a reference or an identification of one or more attributes of the audio output being transmitted. After the beam property input is received 5404, one or more properties of the beam are determined 5406 from the property input. If this property is beam-direction related, the input may set the controlled transmission direction of the beam. This controlled transmission direction is the direction in which the output is transmitted. The received audio signal is converted 5408 to an ultrasonic signal having appropriate properties, which may include one or more of the determined properties. Finally, the directional speaker is driven 5410 to produce an ultrasonic output with appropriate properties. With the beam direction set, the ultrasonic wave output is directed in the controlled transmission direction. After step 5410, the directional audio transmission process 5400 is complete and terminates. Note that the controlled transmit direction may be changed dynamically or periodically as desired.

Fig. 39 shows an example of a property 5500 of a controlled audio output signal according to the invention. These properties may be used for the beam property control unit 5224. One of these properties, which has been described above, is the direction 5502 of the beam. Another attribute may be beam width 5504. In other words, the width of the ultrasonic output can be controlled. In one embodiment, the beamwidth refers to the beamwidth at the predetermined location. For example, if the predetermined location is 10 feet in front of the directional audio device, the beamwidth is the beamwidth at that location. In another embodiment, beam width 5504 is defined as the beam width at its Full Width Half Maximum (FWHM).

The predetermined beam coverage distance 5506 may also be set. In one embodiment, this predetermined distance may be set by controlling the rate of attenuation (attenuation) of the ultrasonic/audio output. In another embodiment, this covered distance may be controlled by changing the volume or magnification (volume or amplification) of the beam. By controlling the predetermined distance, others in the vicinity of the person receiving the audio signal (but not in close proximity) will hear little or no sound at all. Even if the sound is heard by these people, its sound level is greatly attenuated (e.g., any heard sound is weak and almost indistinguishable).

There may be more than one beam. Thus, one of the beam properties is the number of beams used 5512. Multiple beams may be used so that multiple persons can receive the audio signals through the ultrasonic output produced by the directional loudspeaker (or loudspeakers). Each beam may have its own properties.

These attribute inputs may be provided automatically, such as periodically, or manually, such as at the request of the user.

Also, there may be a dual operation mode, 5514-directional mode and normal mode. The directional audio device may comprise a common speaker. For example, in some cases, a user may wish to have audio output heard by everyone in the room. In this case, the user may deactivate the directional transmitting mechanism of the device or have the directional audio device direct these audio signals to a common speaker to produce audio output. In one embodiment, a conventional speaker produces an audio output from an audio signal without producing an ultrasonic output. However, directional loudspeakers require an ultrasonic signal to produce an audio output.

Other types of beam attribute inputs also exist. For example, the inputs may be the position 5508 of the beam, the size 5510 of the beam. The location input may be related to the location of the person wishing to hear the audio sounds or to the location of the electronic device, such as a remote control. Thus, beam attribute control unit 5504 receives beam position inputs and beam size inputs and then decides how to drive directional speaker 5506 to deliver audio sounds to a particular location with an appropriate beam width. Then, the beam property control unit 5504 generates driving signals such as ultrasonic signals and other control signals. These drive signals control directional speaker 5506 to produce ultrasonic outputs for transmission to a particular location at a particular beam size.

FIG. 40 illustrates another exemplary architectural layout 5600 for one application of the present invention. This exemplary structural layout 5600 is generally similar to the exemplary structural layout plan 5320 shown in fig. 37B. In this example, a typical architectural layout plan 5600 includes a first room 5602, a second room 5604, and a third room 5606. Although the first user (u-1), the second user (u-2) and the third user (u-3) are in the first room 5602, only the first user (u-1) and the second user (u-2) desire to hear the audio sounds produced by the audio system. Similarly, the first room 5602 includes a directional audio device 5608 that outputs an ultrasonic cone 5610 (or beam) to the first user (u-1) and the second user (u-2). Note that the width or cross-sectional area (footprint) of cone 5610 can be larger than cone 5330 shown in FIG. 37B, such that it can substantially cover both the first user (u-1) and the second user (u-2). However, by the above-described method of generating an ultrasonic output via the directional audio device 5608, the third user (u-3) is not significantly disturbed by the audio sounds heard by the first user (u-1) and the second user (u-2).

Note that cone 5610 or the beam need not be directed to the first user (u-1) and the second user (u-2). In one embodiment, the beam may propagate to the ceiling of the room and reflect toward the floor for reception by the user. Such an embodiment has the advantage of extending the propagation distance, so that the beam width is widened when the beam reaches the user. Another feature of this embodiment is that the user's position need not be in the line of sight of the directional audio device.

Fig. 41 is a flowchart of a directional audio transmission process 5700 according to another embodiment of the present invention. This directional audio transmission processing 5700 can be done, for example, by the directional audio transmission device 5104 shown in fig. 35. More specifically, this directional audio transmission process 5700 is particularly suitable for the directional audio transmission device 5220 shown in fig. 36B.

Directional audio transmission processing 5700 receives 5702 an audio signal for directional transmission. The audio signal is provided by an audio system. In addition, two beam attribute inputs are received, position input 5704 and beam size input 5706, respectively. Next, the directional audio transmission process 5700 determines 5708 a transmission direction and a beam size from the position input and the beam size input. The distance covered by the predetermined beam may also be determined. The audio signal is then converted 5710 into an ultrasonic signal having suitable properties. For example, the frequency and/or power level of the ultrasonic signal may be set to preset the propagation distance of the beam. Thereafter, a directional speaker (e.g., an ultrasonic speaker) is driven 5712 to produce an ultrasonic output that meets the transmit direction and beam size requirements. In other words, when the directional speaker is driven 5712, it produces an ultrasonic output (carrying audio sounds) to a particular location, arriving at that location with a particular beam size. In one embodiment, the ultrasonic signal is determined by the audio signal, and the transmit direction and beam size are applied to control the directional speaker. In another embodiment, the ultrasonic signal is determined not only by the audio signal but also by the transmission direction and the beam size. After step 5712, the directional audio transmission process 5700 is complete and terminates.

Fig. 42A is a flowchart of a directional audio transmission process 5800 according to yet another embodiment of the invention. This directional audio transmission process 5800 is applicable to, for example, the directional audio transmitting apparatus 5104 shown in fig. 35. More particularly, the directional audio transmission process 5800 is particularly applicable to the directional audio transmission device 5220 shown in fig. 36B, whose beam attribute inputs are the beam position and beam size received from one remote device.

The directional audio transmission process 5800 first enables a directional audio device that is capable of directionally limiting the transmission of audio sounds. Decision 5804 determines whether a beam attribute input has been received. Here, the audio device has an associated remote control device that can provide these beam properties. Generally, the remote control device allows a user to change settings or characteristics of the audio device at a remote location (e.g., but within a line of sight). One of the beam properties is a preset beam position. Another attribute is the size of the beam. According to the present invention, a user of an audio device may hold a remote control device and may send signals as location coordinates to the directional audio device. This may be done, for example, by the user selecting a key on the remote control device. This key may simply be a key to set the beam size because the position signals may be transmitted simultaneously when the beam size information is transmitted. The beam size signal may be sent by various means, such as by a button, dial, or key press, using a remote control device. When decision 5804 determines that no attributes have been received from the remote control device, it waits for an input.

When the decision 5804 determines that a beam attribute input from the remote control device is received, the control signals for the directional speaker are determined 5806 based on the received attributes. If the attribute is a position coordinate, the transmission direction can be determined based on the position coordinate. If the property is for adjustment of beam size, a control signal to set a particular beam size is determined. Based on these determined control signals, a predetermined controlled ultrasonic output is then generated 5812.

Next, decision 5814 determines whether additional attribute inputs remain. For example, an additional attribute may be provided to gradually increase or decrease the size of the beam. The user can adjust the beam size and then further adjust it according to the heard effect, and so on. When the decision 5814 determines that there is additional attribute input, an appropriate control signal is determined 5806 to adjust the corresponding ultrasound output. When the decision 5814 determines that there are no additional attribute inputs, the directional audio device can be set to an inactive state. When the decision 5816 determines that the audio system is not in an inactive state, the directional audio transmission process 5800 returns to continue outputting the controlled audio output. On the other hand, when the decision 5816 determines that the audio system is in an inactive state, the directional audio transmission process 5800 completes and terminates.

In addition to delivering directionally controlled audio sounds to a user, the audio sounds can be further altered or modified according to the hearing characteristics or preferences of the user, or according to the audio state of the user's immediate surroundings.

Fig. 42B is a flowchart illustrating an environmental adaptation process 5840 according to an embodiment of the present invention. The environmental adaptation process 5840 determines 5842 characteristics of the environment. In one implementation, these environmental characteristics may refer to measured sound (e.g., noise) levels in the user's immediate surroundings. The sound level may be measured by a receiver (e.g., a microphone) in the user's vicinity. This capture may be on a remote control held by the user. In another implementation, such environmental characteristics may refer to an estimated sound (e.g., noise) level in the vicinity of the user. The sound level of the user's nearby surroundings can be estimated based on the location of the user/device and the estimated sound level of the particular environment. For example, the sound level of a department store is higher than the sound level in the field. The user's location may be determined, for example, by a Global Positioning System (GPS) or by other triangulation techniques, such as by infrared, Radio Frequency (RF) or ultrasonic frequencies having at least three non-collinear reception points. There may be a database of information about typical sound levels at different locations. The database can be found to derive an estimated sound level for a particular location.

After the environmental adaptation process 5840 makes the determination 5842 of the environmental characteristics, the audio signal is modified according to these environmental characteristics. For example, if the user is in an area with a lot of noise (e.g., ambient noise), such as in a crowded confined space, or in an environment with construction noise (building noise), the audio signals may be processed to minimize unwanted noise, and/or the audio signals (e.g., in a desired frequency range) may be amplified. One of the solutions to suppress the unwanted noise is to introduce an audio output in phase opposition to the unwanted noise to cancel the noise. In the case of amplification, if the noise level is too great, the audio output may not be amplified to cover the noise, as the user may not be able to safely listen to the audio output. In other words, there may be a limit to the amount of amplification, and when the noise level is too great, the audio output may be negatively amplified (or even completely suppressed). Noise suppression and amplification may be achieved by conventional digital signal processing, amplification and/or filtering techniques. The environment adaptation process 5840 may, for example, be performed periodically or if the audio signal has an interruption exceeding a predetermined time, which may indicate that a new audio stream is coming in.

A user's hearing profile includes his hearing characteristics (hearing characteristics). By altering or modifying the audio sounds according to the hearing characteristics of the user, the audio sounds provided to the user can be customized or personalized for the user. By customizing or personalizing the audio sounds delivered to the user, the audio output may be improved in a manner that is more conducive to the user's enjoyment of entertainment.

FIG. 42C is a flowchart of an audio personalization process 5860, according to one embodiment of the invention. The audio personalization process 5860 obtains 5862 audio personal data associated with the user. The hearing profile contains information detailing the hearing characteristics of the user. For example, a user may be given his hearing profile by receiving a hearing test. The audio signal may then be modified 5864 or pre-processed according to the audio profile associated with the user.

The hearing profile may be provided to the directional audio transmission device performing personalization 5860 via a variety of different ways. For example, audio personal data may be provided electronically to a directional audio transmitting device over a network. As another example, audio personal data may be provided to the directional audio delivery device via a removable data storage device (e.g., a memory card). For additional details regarding audio profiling and personalization to enhance hearing, see other sections of this patent application.

Environmental adaptation process 5840 and/or audio personalization process 5860 may be performed with any of the directional audio transmission devices or processes discussed above. For example, the environmental adaptation process 5840 and/or the audio personalization process 5860 may optionally be implemented in conjunction with the directional audio transmission process 5400, 5700, or 5800 embodiments discussed above in fig. 38, 41, and 42. The environmental adaptation process 5840 and/or the audio personalization process 5860 generally occur before step 5408 in fig. 38, step 5710 in fig. 41, and/or step 5812 in fig. 42A.

Fig. 43A is a perspective view of an ultrasonic transducer 5900, according to one embodiment of the invention. The ultrasonic transducer 5900 may implement a directional speaker as discussed herein. The ultrasonic transducer 5900 generates the previously mentioned utilized ultrasonic output. In one embodiment, the ultrasonic transducer 5900 includes resonator tubes (resonance tubes)5902 covered with a piezoelectric film such as PVDF to which a voltage is applied, as described in another section of this application.

Mathematically, the resonance frequency f of each characteristic mode (n, s) of a circular membrane can be expressed by the following mathematical formula:

f(n，s)＝α(n，s)/(2πa)*√(S/m)

here, the

a represents the radius of the circular membrane,

s represents a uniform pressure per unit boundary length (uniform tension),

m represents the mass per unit area of the circular film.

For the different characteristic modes of the tube structure shown in figure 43A,

α(0，0)＝2.4

α(0，1)＝5.52

α(0，2)＝8.65

...

let α (0, 0), the fundamental resonance frequency, be set to 50 kHz. Then, α (0, 1) is 115kHz, α (0, 2) is 180kHz, and so on. The modes with n equal to 0 are all axisymmetric modes. In one embodiment, the structure is resonant by driving the membrane at a suitable frequency, such as at any one of the axisymmetric mode frequencies, to generate ultrasound at this frequency.

In another embodiment, instead of using a circular membrane on the resonator tube, the ultrasonic transducer is composed of a number of speaker elements, such as unimorph (unimorph), bimorph or other types of multilayer piezoelectric radiating elements. The elements may be mounted on a solid surface to form an array. These transmitters can operate over a wide continuous frequency range, say from 40kHz to 200 kHz.

In one embodiment, the propagation distance of the ultrasonic output is controlled by varying the carrier frequency, such as from 40kHz to 200 kHz. Frequencies in the 200kHz range have a much greater acoustic attenuation in air than in the 40kHz range. The ultrasound output will then decay at a much faster rate at higher frequencies, thereby reducing the potential risk of ultrasound causing health hazards, if any. It is noted that the degree of attenuation may be continuously varied, for example, in a multilayer piezoelectric thin film device, the carrier frequency may be continuously varied to continuously vary the degree of attenuation. In another embodiment, the isolation may be varied non-continuously, such as by changing from one characteristic mode to another characteristic mode of a pipe resonator (tuberesonator) with a piezoelectric circular membrane.

Fig. 43B is a schematic diagram of an ultrasonic output beam 5904 generated by ultrasonic transducer 5900.

The width of the beam 5904 can be varied in a variety of different ways. The width of the beam 5904 may be reduced, for example, by reducing the area of the transducer 5900 or using only a portion thereof. In this example of a circular membrane covering the resonator tube, there may be two concentric circular membranes, the inner one of which is 5910 and the outer one of which is 5912, as shown in fig. 43C. The user may switch on only the inner circular membrane or both circular membranes simultaneously with the same frequency to control the beam width. Fig. 43D illustrates another embodiment 5914, where the transducer is divided into four quadrants (quadratant). The circular membrane of each quadrant can be controlled individually. They may be switched on individually or in any combination to control the beamwidth. In the example of a directional speaker using a bimorph element array, the size of the beam width can be reduced by reducing the number of elements. Another solution is to activate certain portions of the elements to control the beamwidth.

In yet another embodiment, the beam width may be increased by increasing the frequency of the ultrasound output. To demonstrate this embodiment, the size of the directional loudspeaker is much larger than the ultrasonic wavelength. Therefore, the beam divergence caused by pinhole diffraction (aperture diffraction) is small. In the present embodiment, one of the reasons why the beam width is increased is due to an increase in attenuation closely related to the ultrasonic frequency. See, for example, FIGS. 43E-43G, wherein the ultrasonic frequencies are 40kHz, 100kHz and 200kHz, respectively. These figures show the beam pattern (beam pattern) of the audio output, which is found by integrating the nonlinear KZK equation at an audio frequency of 1 kHz. Assume that the emission surface of the directional loudspeaker is a flat surface of 20 cm by 10 cm. Examples of the description of these equations can be found in "Quasi-plane waves in the nonlinear acoustics of confined beams" article, e.a. zabolotskaya, incorporated with r.v. khokhov, sov.phys.acoust, vol.15, pp.35-40, 1969; and "Equations of nonlinear acoustics", V.P. Kuznetsov, Sov.Phys.Acoust., Vol.16, pp.467-470, 1971.

In the examples shown in FIGS. 43E-43G, the attenuation at a frequency of 40kHz is assumed to be 0.2 per meter, 0.5 per meter at 100kHz, and 1.0 per meter at 200 kHz. These beam patterns are calculated to be located 4 meters from the emitting surface and perpendicular to the propagation axis. The values on the X-axis represent the distance of the test points from the axis (from-2 meters to 2 meters), and the values on the Y-axis represent the dB SPL sound pressure levels of the audio output calculated at each test point. The transmit power of the three examples is normalized so that the power of the three on-axis audio outputs received is substantially the same (e.g., 56dBSPL 4 meters away). Comparing these values, it can be seen that the beam is narrowest when the carrier frequency is lowest (40 kHz in fig. 43E) and widest when the carrier frequency is highest (200 kHz in fig. 43G). One explanation is that higher acoustic attenuation reduces the virtual array (virtual array) length of the loudspeaker elements, which can broaden the beam pattern. In summary, in this embodiment, the lower carrier frequency provides better beam isolation, enhancing privacy.

As explained previously, the audio output propagates in the steered beam, thereby enhancing privacy. Sometimes, a user may wish to have a wider or more divergent beam, although he is not willing to cause interference to others around. For example, a couple sits together to watch a movie. If one of the stations fails to hear the movie sound because the beam is too narrow, their enjoyment is greatly compromised. In some embodiments described below, the width of the beam may be widened in a controlled manner based on curved structured surfaces or other phase-modifying beamforming techniques.

Figure 44A illustrates a solution based on an ultrasonic speaker with a curved convex emitting surface to diverge the beam. The surface may be curved in a convex manner in the structure to create a diverging beam. The embodiment shown in fig. 44A has an ultrasonic speaker 6000 of a spherical shape, or the ultrasonic output emitting surface of the ultrasonic speaker is spherical. In the spherical device 6000, there are attached (e.g., bimorph) or integrated ultrasound elements 6004 on the spherical surface 6002. An ultrasonic speaker with a spherical surface 6002 forms a spherical radiator that outputs an ultrasonic output in a cone (or beam) 6006. While this cone will generally diverge due to the curvature of the spherical surface 6002, the cone 6006 will remain directionally limiting.

In one embodiment, the speaker elements are fixed or attached to a spherical surface, and each ultrasound element 6004 points toward the center of the sphere to which the spherical surface 6002 belongs. In one embodiment where these elements are integrated into a spherical or curved surface, there may be a number of resonator tubes 6026 as shown in fig. 44B. The longitudinal axis (length-wise axis) of each resonant cavity 6026 is directed toward the center of the sphere to which spherical surface 6002 belongs. The resonator tube 6026 may be formed in a single manufacturing step to ensure their conformity. This may be achieved, for example, by press forming all of the bores simultaneously.

In one embodiment, the ultrasonic speaker includes a plurality of resonator tubes with a thin film piezoelectric circular membrane mounted on one side of the tubes. It can be on convex side 6034 or concave side 6036, as shown in FIG. 44B. In the embodiment 6010 shown in FIG. 44B, the circular membrane is assumed to be installed on the side of the concave surface. After the membrane is mounted, a vacuum is created to press the membrane against the tube. A voltage may be applied across the circular membrane to produce an ultrasonic output. This creates an emitting surface that is curved in a concave manner in the structure. As shown in fig. 44B, the resulting beam 6040 initially converges and then diverges.

Divergence is determined, for example, by the degree of curvature of surface 6002 or 6003. In one embodiment, referring back to fig. 44A, the radius of the sphere is about 40 cm, its height 6006 is about 10 cm and its width 6008 is about 20 cm.

Even if the emitting surface of the ultrasonic speaker is a flat surface, a divergent beam can be generated. For example, as shown in fig. 44C, beam 5904 can be reflected as a diverging beam 5918 (thus increasing the beam width) using a convex reflector 6050. In this embodiment, the ultrasonic speaker may be defined to include a convex reflector 6050.

Another method of adjusting the beam shape (e.g., diverging or converging the beam) is by controlling the phase. In one embodiment, the directional loudspeaker includes a number of loudspeaker elements, such as bimorphs. The phase shift of each element of the loudspeaker can be controlled separately. With appropriate phase shifting, the ultrasonic output of a secondary phase wave front (quadratically phase wave-front) can be produced to produce a converging or diverging beam. For example, the phase of each transmit element is modified by k r2/(2F0), where (A) r is the radial distance of the transmit element, and the origin of the radius appears to be the origin of the diverging beam, and (B) F₀Is a predetermined focal length, and (c) k is a propagation constant of the audio frequency f, equal to 2 pi f/c₀，c₀Is the speed of sound.

In yet another example, the beam width may be changed by modifying the focal point and focal length of the beam, or by defocusing the beam (de-focusing). This can be achieved via electronic adjustment of the relative phases of the ultrasonic signals exciting the different directional loudspeaker elements.

The beam width or the propagation direction of the beam can also be controlled by segmenting the curved surface. Figure 45A illustrates a cylindrical ultrasonic speaker 6100, according to an embodiment of the present invention. In this embodiment, the emission surface of the directional loudspeaker is cylindrical and segmented. In the cylindrical device 6100, a cylindrical surface 6102 is fixed (e.g., bimorph) or integrated (e.g., tubes covered by a thin film) with a plurality of ultrasound elements 6104. Each ultrasonic element 6104 is oriented horizontally, but pointing toward the central axis of the cylinder to which the cylindrical surface 6102 belongs. In the case where the elements are resonator tubes, the longitudinal axis of each tube is horizontal and directed toward the centerline of the cylinder to which the cylindrical surface 6102 belongs. Furthermore, although the cone of ultrasonic output 6106 will normally diverge, the cone will remain directional. In one embodiment, the radius 6108 of the cylindrical surface is about 40 cm, the height 6110 is about 10 cm, and the width 6112 is about 20 cm.

In the speaker embodiment shown in fig. 45A, the transducer surface 6102 may be segmented, such as into three individually controllable segments 6102, 6104, and 6106. Each segment (segment) can be independently actuated to control the direction and/or width of the ultrasound output. For embodiments where the loudspeaker is a tube covered by a membrane, each segment has its own membrane. To produce the widest beam, the three segments are simultaneously activated by signals having substantially the same frequency, phase and amplitude.

Fig. 45B shows another example of an emission surface segmentation according to the present invention. The transducer face 6140 has a curved structure 6142 comprising four controllable segments 6144, 6146, 6148, and 6150. Each segment of the flexure structure 6142 can be independently selectively activated to control the direction and/or width of the ultrasonic output. For example, the ultrasound waves generated by the segment 6144 are output in a confined area 6152. The ultrasound waves generated by the segment 6146 are output in a confined zone 6154. The ultrasound waves generated by segment 6148 are output in a confined zone 6156. The ultrasound waves generated by segment 6150 are output in a confined zone 6158. By independently controlling these controllable segments of the curved structure 6142, the width of the ultrasonic output (and thus the width of the audio output generated thereby) can be controlled.

The segmentation of the transducer surface shown in fig. 45B may be accomplished by switching on the different segmentation units. To illustrate this, referring to FIG. 44A, a subset of the ultrasound elements 6004 may be activated. For example, a spherical transmitter has 64 ultrasound cells 6004, which may be bimorphs. For example, if only the inner 16 ultrasound elements are activated, a smaller beam may be emitted.

Furthermore, the propagation direction of an ultrasound beam, such as beam 6006 in fig. 44A, beam 6040 in fig. 44B, or beam 6106 in fig. 45A, may also be changed by electrical and/or mechanical mechanisms. To illustrate the spherical ultrasonic speaker shown in fig. 44A, the user may change the position of the spherical surface 6002 to change its beam orientation or direction. A motor may also be mechanically coupled to the spherical surface 6002 to change its orientation or the direction of propagation of the ultrasonic output. In another embodiment, the beam direction may be changed electronically based on phased array technology.

The spherical surface 6002 can be moved to adjust the sending direction by tracking the user's movement. This tracking may be performed dynamically. This may be done by different mechanisms, such as by Global Positioning System (GPS) or other triangulation techniques. The position of the user is fed back to or calculated by the directional audio device. This position thus becomes a beam property input. The beam property control unit will convert the property input into an appropriate control signal to adjust the direction of transmission of the audio output. Movement of the spherical surface 6002 may also be in response to user input. In other words, such movement or positioning of the beam 1006 may be automated or may be directed by a user.

Fig. 46A and 46B are perspective views of one embodiment of a directional audio device that provides directional audio output to a user of interest. FIG. 46A illustrates a directional audio device 6200 that includes an entertainment center, such as a television 6202, a set-top box 6204, and directional speakers 6206. Television 6202 plays back, for example, a video signal provided via a satellite link or a cable connection via a set-top box. Typically, set top box 6204 decodes encoded video and audio signals transmitted over a satellite link or cable. Once decoded, the appropriate video and audio signals are transmitted to the television 6202. The television 6202 may have conventional or ordinary speakers to provide audio output. These speakers generally do not produce ultrasonic signals and then convert them in the air to an audio frequency range to produce an audio output. But the audio device 6200 includes a directional speaker 6206. The directional speaker 6206 transmits an audio signal in a limited direction. In addition, the directionally limited audio output can be controlled to deliver the user's target distance, while the width of the generated audio beam can also be controlled. The directional speaker 6206 generates an ultrasonic output through the emitting surface 6208. The emitting surface 6208 may comprise a single or multiple segmented ultrasound or speaker units.

In addition, the directional speaker 6206 is mounted on the set-top box 6204 so that its position can be adjusted depending on the condition of the set-top box 6204 and the television 6202. For example, the directional speaker 6206 may be rotated to change the direction of transmission of the directional control audio output. In one embodiment, a user of the audio system 6200 may manually adjust (e.g., rotate) the orientation of the directional speaker 6206 to adjust the transmit direction. In another embodiment, the directional speaker 6206 may be azimuthally adjusted (e.g., rotated) by a motor provided within the set-top box 6204 or the directional speaker 6206. Such motors may be controlled by conventional control circuitry and may be implemented via the set-top box 6204, directional speaker 6206, or one or more buttons on the remote control device.

Fig. 46B is a schematic diagram of another directional audio device 6220 in a set-top box environment in accordance with another embodiment of the present invention. The audio device 6220 includes an entertainment system such as a television 6222, a set-top box 6224 and directional speakers 6226. The set-top box 6224 is typically connected to a satellite line or cable line to receive audio and video signals. The set top box 6224 decodes the audio and video signals and provides the audio and video signals generated thereby to the television 6222. The television 6222 displays these video signals and may generate audio sounds with its conventional speakers. However, when directional transmission of audio sounds is desired, the conventional speaker of the television 6222 is not employed. But instead a directional loudspeaker 6226. The directional speaker 6226 may be activated, for example, by a button, switch, or other method. Once activated, the directional speaker 6226 outputs audio signals in a directionally limited manner. In one embodiment, the television 6222 has an audio output connection to a set-top box 6224. If a conventional speaker is selected, the signal line to the audio output connection is powered down and the normal audio output is output directly by the television 6222. If, however, a directionally limited audio output is desired, the audio signal generated by the television 6222 is transmitted to the set-top box 6224 while the normal audio output of the television 6222 is not enabled. In another embodiment, the volume control of the television 6222 may also be turned down if a direction is selected to limit audio output.

Still further, the set-top box 6224 and/or directional speaker 6226 can control the distance and/or width of the transmissions for those audio outputs that are transmitted to one or more interested users. In this embodiment, the position of the directional speaker 6226 is fixed relative to the set-top box 6224. In one embodiment, the directional speaker 6226 is mounted on a set-top box 6224. In another embodiment, the directional speaker 6226 is integrated with the set-top box 6224. The direction of the directional limiting audio output may be electronically controlled by a variety of different techniques. One technique is to activate only certain segments of the emitting surface 6228 of the directional speaker 6226. Another technique is to use beam-steering operation (beam-steering operation) based on phase control input.

The directional audio devices 6200 and 6220 illustrated in fig. 46A and 46B may employ various methods and processes discussed above. The set-top box with directional speakers shown in fig. 46A and 46B can convert a conventional audio system in a television into an audio system with directional audio delivery capability as described herein.

For example, the emitting surface 6140 of the directional speaker shown in fig. 45B can be used as the emitting surface 6228 of the directional speaker 6226 illustrated in fig. 46B. For example, only segment 6146 is active initially. The user signals to the set-top box that it should increase the beamwidth. Segment 6148 is then reactivated, thereby increasing the width or relative area of the ultrasonic output (which regenerates the audio output). In another application, non-adjacent segments may be simultaneously activated to produce multiple separate beams. The user can signal the set-top box to activate the outermost two beams 6152 and 6158, for example. This will produce two separate beams for two separate users. Thus, a person between the two users will only hear the output level that has been greatly attenuated.

In another example, more than one user may be seated near the television 6200, as shown in FIG. 46A. In this case, it is advantageous to cover a beam having a short distance but a wide beam. In one embodiment, a directional speaker 6206 operating at a higher frequency is used, such as the directional speaker operating at 200kHz shown in fig. 43G. Its beam width is wider than that shown in fig. 43E, but its coverage distance is shorter due to the larger attenuation.

Fig. 47 is a perspective view of a remote control device 6300 according to one embodiment of the present invention. Remote control 6300 is one embodiment of a directional audio device. As with a normal remote controller, the upper surface 6302 of the remote control device 6300 has a number of keys 6304. Some of the keys correspond to various directional function selections by which a user may manipulate the directional audio device via the remote control device. These function selections include start, stop, play, channel selection, volume control, etc. In one embodiment, the remote control device 6300 also includes selections of beam attribute inputs such as three beam widths (large, medium, and small), and three coverage distances (long, medium, and short).

The remote control device 6300 may also include a directional speaker 6306 that produces directional audio to be transmitted to one or, at most, several users willing to hear the audio output. Directional speaker 6306 may be substantially flush with upper surface 6302 or relatively recessed. Optionally, a grating 6308 may be mounted over directional speaker 6306 as desired. The directional loudspeaker may also be mounted at an angle relative to the surface 6302, or may be mounted movably, for flexible steering of the transmit direction. If desired, directional speaker 6306 may optionally be covered with a thin layer of material (e.g., a plastic housing) to provide protection, but still allow sound to pass through. For further details regarding directional loudspeaker 6306, see other sections of this application. A wireless link window 6310 provides a window that allows the remote control device 6300 to communicate wirelessly (e.g., radio or light) with an audio system, which may or may not have directional audio capability. Audio signals may then be received and directed via directional speaker 6306 to one or at most several users in the vicinity of the remote control device 6300.

Sometimes, reducing its power level in free space may be beneficial to avoid any potential health hazards (if any), depending on the power level of the ultrasound signal. Fig. 48A-48B show two embodiments that can be used for this purpose. Fig. 48A illustrates a directional speaker with a flat ultrasonic output emitting surface 6404. The size of the flat surface may be much larger than the wavelength of the ultrasonic signal. For example, the ultrasonic frequency is 100kHz and the flat surface size is 15 cm, 50 times larger than the ultrasonic wavelength. Because of the much larger size, the ultrasonic waves emitted from the surface are contained within the housing 6402 and do not diverge significantly. In the example shown in fig. 48A, the directional audio device 6400 includes a housing 6402 having at least two ultrasound reflecting surfaces. The emitting surface 6404 generates an ultrasonic wave, which propagates in the beam 6406. The beam is reflected back and forth at least once in the housing 6402 by the reflective surface 6408. After multiple reflections, the beam is emitted out of the opening 6410 of the housing as output audio 6412. The dimensions of the opening 6410 may be about the dimensions of the emitting surface 6404. In one embodiment, the final reflective surface may not be a planar reflector, but rather a concave or convex surface 6414, producing a converging or diverging audio output 6412 beam, respectively. Also, at the opening 6410, an ultrasonic absorber may be installed to further reduce the power level of the free-space ultrasonic output.

Fig. 48B shows another embodiment of a directional audio transmission device 6450 that allows ultrasonic waves to be reflected back and forth at least once by an ultrasonic-wave reflecting surface before being emitted into free space. In fig. 48B, the directional speaker has a concave emitting surface 6460. As explained in fig. 44B, this concave surface first converges the beam. For example, the concave surface 6460 focus 6464 is located at the midpoint of the beam path inside the housing. Since the final reflective surface 6462 may be flat, concave, or convex, the beam width at the opening 6466 of the housing may not be much larger than the beam width of the emitting concave surface 6460. However, at the emitting surface 6460, the beam is convergent. And at opening 6460 the beam is diverging. The degree of curvature of the transmitting and reflecting surfaces can be calculated based on the desired focal length or beam divergence angle, similar to techniques used in optics, such as those used in telescope configurations.

The stereo effect may be provided by configuring more than one directional audio transmission device. Fig. 49 shows such an embodiment in a structural layout plan view 6500. An audio system 1506 is coupled to two separate directional audio devices 6502 and 6504. In one arrangement, the audio system transmits different types of audio signals, wired or wireless, to the two directional audio transmitting devices 6502 and 6504. For example, different types of audio signals may represent a left channel and a right channel, respectively. The two directional audio transmitting devices 6502 and 6504 produce two directionally limited audio output beams 6510 and 6512 which are directed toward and received by the user 6508. Note that the number of directional audio transmitting devices is not limited to two. For example, a surround sound configuration may be obtained with more than two directional audio transmission devices.

Many of the attributes of the limited audio output may be adjusted, either by the user or automatically and dynamically based on some monitoring or tracking measure, such as a measure of the user's position.

One of the properties that can be adjusted is the direction of the limited audio output. It can be controlled, for example, in several ways: (a) actuating different segments of a flat or curved speaker surface, (b) using a motor, (c) manually moving a directional speaker, or (d) by phased array beam steering techniques.

Another property that can be adjusted is the beamwidth of the controlled audio output. It can be controlled, for example, in several ways: (a) adjusting the frequency of the ultrasonic signal, (b) activating one or more segments of the speaker surface, (c) using phased array beamforming techniques, (d) diverging the beam using a curved speaker surface, (e) changing the focus of the beam, or (f) defocusing the beam.

Isolation or privacy may also be controlled independently of the beamwidth. For example, a relatively short-range, but wide beam can be obtained by increasing the frequency of the ultrasonic signal. Isolation or privacy may also be controlled in some way, such as (a) phased array beamforming techniques, (b) adjusting the focus of the beam, or (c) defocusing the beam.

The volume of the audio output can be adjusted in some way, for example, (a) to change the amplitude of the ultrasonic signal driving the directional speaker, (b) to adjust the ultrasonic frequency to change its coverage distance, or (c) to enable more segments of a flat or curved speaker surface.

The audio output may also be personalized or adjusted according to the audio environment surrounding the directional audio device. Signal pre-processing techniques may be applied to the audio signal to achieve this personalization and adjustment.

Increasing the path length of the ultrasonic wave (from the directional speaker to free space) before it is emitted into free space can reduce, if any, the harm of the ultrasonic wave. An ultrasonic absorber may also be used to attenuate the ultrasonic waves before they are transmitted into free space. Another way to reduce potential harm, if any, is to increase the frequency of the ultrasonic signals to reduce their coverage distance.

The stereo effect can also be obtained by using more than one directional audio transmission device separated from each other. This will produce a number of different limited audio outputs, thereby creating a stereo effect for the user.

The directionally controlled audio outputs are not limited to being generated by a set-top box, but they may also be generated by a remote control device.

Some embodiments of the invention are illustrated using a structural layout plan, applied to an indoor environment. However, many embodiments of the present invention are also well suited for outdoor applications. For example, a user may be seated in a courtyard to read a book while listening to music played from the directional audio apparatus of the present invention. The device may be placed outdoors 10 meters from the user. Due to the directionally limited nature of the audio output, the sound may be confined to the immediate surroundings of the user. Thus, the noise pollution degree to the neighbors of the user is greatly reduced.

In addition, existing audio systems may also be modified using any of the set-top boxes described above to produce a directionally-limited audio output. The user can select the directional control audio output or the general audio output of the audio system as desired.

Wireless audio

Some embodiments of the invention relate to wireless transmission of audio sounds produced by an audio system, which may be stationary, but is typically portable for personal audio devices. These techniques may allow a user of a personal audio device to still obtain audio sounds while the user is on the move. According to various embodiments, the audio system may be readily adapted to provide wireless transmission of audio sounds. These techniques also enable customization (or personalization) of the selection of audio sounds to be provided as desired for the user's hearing, and/or modification of audio sounds based on environmental conditions.

In accordance with an aspect of the invention, audio output produced by an audio system may be transmitted to one or more persons desiring to hear the audio output. Each person has a personal audio device. The device enables audio sounds corresponding to audio output produced by an audio system to be personalized in a directionally limited manner. Thus, those who do not wish to hear the audio output do not receive a significant amount of the audio sounds. Thus, they are less disturbed by unwanted audio sounds.

According to another aspect of the invention, a wireless adapter can be provided as an after market modification to an audio system. The wireless adapter enables audio output produced by the audio system to be wirelessly transmitted to one or more personal audio devices. Each personal audio device produces audio sounds for its user.

Fig. 50 is a block diagram of a remote controlled audio transmission system 7100, according to one embodiment of the present invention. The remote audio delivery system 7100 includes an audio system 7102 for generating audio output. The audio system 7102 is, for example, a television, CD player, DVD player, stereo system, computer with speakers, etc. In one embodiment, audio system 7102 may also refer to an entertainment system. In another embodiment, the audio system 7102 is stationary. Audio output produced by the audio system 7102 is provided to the wireless transmitting device 7104. In one implementation, the wireless transport device 7104 is connected to an audio output port (e.g., terminal, connector, receptacle, etc.) of the audio system 7102. The connection may be a direct termination between the two or may be made by a cable. In one embodiment, the wireless transport device 7104 may also be used as a wireless audio adapter, since it enables the audio system 7102 to be adapted for wireless audio transmission without any change.

The wireless transmission device 7104 receives audio output generated by the audio system 7102 and transmits the audio output over a wireless channel 7105 (or wireless connection) to the wireless receiver 7106 of the personal audio device 7107. The wireless channel 7105 is typically a short range wireless connection that is not within the audio frequency range, such as may be obtained using bluetooth, WiFi, or other dedicated frequency (e.g., 900MHz, 2.4GHz) technology. The wireless receiver 7106 receives audio output transmitted by a wireless transmitting device 7104 over a wireless channel 7105. The received audio output is then supplied to the control circuit 7108. The control circuit 7108 converts the received audio output into a speaker driving signal. This speaker drive signal is then applied to activate directional speaker 7110 to produce an output sound. The output sound produced by directional speaker 7110 is directionally limited to enhance privacy. As will be discussed in detail below, the control circuit 7108 may also provide customization or personalization as desired for the individual and/or environment.

The directionally limited output sound produced by directional speaker 7110 allows a user of personal audio device 7107 to hear the audio sound even when neither ear is in contact with or connected to directional speaker 7110. However, the directional characteristic of the output sound is directed towards the user (e.g. the user's ear), and privacy is achieved by limiting the output sound to a limited directional area. In other words, bystanders in the vicinity of the personal audio device, but not within the limited directional area, will not hear the output sound produced by the directional speaker or a substantial portion thereof directly. These bystanders may hear a reduced portion of the output sound after reflection off the surface. The decibel level is also reduced (e.g., by at least 20dB) when the reflected output sound, if present, is transmitted to these bystanders, which are difficult to hear clearly.

In one embodiment, directional speaker 7110 is an ultrasonic speaker and control circuit 7208 converts the received audio output to an ultrasonic drive signal to drive the ultrasonic speaker. These ultrasonic drive signals are provided to an ultrasonic speaker to produce an ultrasonic output. The ultrasonic output is then converted, for example, in air to an audio output. In one embodiment, the frequency spectrum of the final generated audio output (after such conversion) is similar to the audio output produced by audio system 7102. In another embodiment, the frequency spectrum of the resulting audio output is adjusted to provide hearing customization (e.g., to enhance hearing), or to adapt to the user's environmental or physical conditions.

Fig. 51 is a block diagram of a remote controlled audio transmission system 7200 according to another embodiment of the present invention. The remote audio transmission system 7200 includes an audio system 7202 and a wireless transmitter 7204. In one embodiment, the wireless transmitter 7204 can also be considered a wireless audio adapter. It enables the audio system 7202 to be adapted for wireless audio transmission without modification. In one implementation, the wireless transmitter 7204 is connected to the audio system 7202 via an audio output port of the audio system 7202. This connection may be made by a connector alone or in combination with a wire. In another embodiment, the wireless transmitter 7204 is integrated into the audio system as part of it, in which case no connector or wires are required. The audio system 7202 and the wireless transmitter 7204 together comprise a wireless audio transmission system.

Audio output generated by the audio system 7202 is provided to the wireless transmitter 7204 through an audio output port of the audio system 7202 or other means. The wireless transmitter 7204 then transmits the audio output to the wireless receiver 7206 of the personal audio device 7207 over a wireless channel (wireless link) 7205. Then, the audio output received by the wireless receiver 7206 is supplied to the control circuit 7208. The control circuit 7208 can receive user information about the user from the data storage device 7202. For example, the information may be audio personal data related to the user. An audio profile includes or is based on the hearing profile of the associated user. The user information may be stored in a data storage device 7210. The data storage device 7210 can be a dedicated or removable data storage medium. Examples of removable data storage media are memory cards (flash cards, memory sticks, credit cards with data storage, PC cards (PCMCIA), etc.).

The control circuit 7208 generates a speaker driving signal for driving the speaker 7212. In the present embodiment, the control circuit 7208 generates a speaker driving signal according to not only the received audio output but also user information. In other words, the control circuit 7208 can adjust the drive signal applied to the speaker 7212 in accordance with the user information. Thus, the audio output produced by speaker 7212 can be customized (or personalized) for the user. For example, when the user information is related to the hearing profile of the user and/or the preferences of the user, the control circuit 7208 can generate customized drive signals for the speaker 7212 such that the audio output ultimately generated by the speaker 7212 can be customized to the hearing profile and/or preferences of the user.

The remote control audio transmission system 7200 shown in fig. 51 utilizes customized personal audio device 7207 audio output. Note that as shown in fig. 51, the personal audio device 7207 may include a wireless receiver 7206, a control circuit 7208, a data storage device 7210, and a speaker 7212. However, it should still be mentioned that this customization may also be done elsewhere. For example, the audio system 7202 or the wireless transmitter 7204 can additionally include control circuitry (not shown) for obtaining user information and customizing the audio output based on this information before it is transmitted to the personal audio device 7207. Such an implementation may provide centralized customization of audio output for one or more personal audio devices.

Fig. 52 is a block diagram of a remote controlled audio transmission system 7300 according to another embodiment of the present invention. The remote audio transmission system 7300 includes an audio system 7302, a wireless network 7304, and personal audio devices 7306 and 7308. The wireless network 7304 may be a wireless local area network, such as a bluetooth or WiFi network. Here, remote audio transmission system 7300 illustrates that audio system 7302 can provide audio output to one or more personal audio devices 7306 and 7308 through wireless network 7304. Wireless network 7304 may be used, for example, in a home or business environment. The audio output produced by audio system 7302 may be broadcast, multicast (multicast), or unicast (unicast) over wireless network 7304. In other words, audio output produced by audio system 7302 may be communicated to one or more personal audio devices 7306 and 7308. In one implementation, each personal audio device is associated with a different web address, and the audio output can then be transmitted to the appropriate personal audio device or devices via the wireless network 7304 using these associated web addresses. Although fig. 52 illustrates only personal audio devices 7306 and 7308, it should be understood that remote audio transmission system 7300 may support many personal audio devices, and that these personal audio devices may be of the same type, or of different types.

As described above, the wireless audio adapter 7204 may be mated with the personal audio device 7207. In other words, each wireless audio adapter may have a personal audio device associated with it.

In another embodiment, the wireless signals generated by the wireless audio adapter 7204 can be received by multiple personal audio devices. This may be accomplished, for example, by broadcasting a signal and requiring all personal audio equipment to tune to the broadcast radio channel. The broadcast may be performed in the analog or digital range. For the latter, the broadcasting may be performed in a third layer (e.g., IP multicast) or a second layer (e.g., IEEE 802.11). If personal customization of the receiver is required, each personal audio device 7307 may first be initialized with the wireless audio adapter 7204. This initialization process may be to require each audio device to transmit an identifier to the adapter over a wireless or wired connection. The adapter then transmits the personalization information to the corresponding personal audio device based on this identifier. After the personalization information is received, the personal audio device may be configured accordingly and then begin receiving audio output.

In yet another embodiment, a personal audio device may be configured for a particular wireless audio adapter or audio system. This configuration is suitable for after-market (after-market), and can be implemented in a variety of ways. For example, there may be switches on both the device and the adapter, or both may have channels. These switches or channels may be selected by the user. The device is configured for this wireless audio adapter when the corresponding switches or channels of the two match. Another solution is based on the address of the Media Address Control (MAC) layer, IP address or TCP or UDP port number. For example, the personal audio device and the wireless audio adapter may both recognize a particular TCP or UDP port number. Thus, they may be configured to receive only packets or signals from that port. The personal audio device and wireless audio adapter may also be identified by a specific IP address, or MAC layer address.

Fig. 53 is a schematic diagram illustrating a structural layout plan view 7400 of various embodiments of the present invention. The floor plan 7400 illustrates an example of a floor plan having a first room 7402, a second room 7404 and a third room 7406. Within the first room 7402 is an Audio System (AS)7408 which includes a wireless transmission device 7410 or wireless audio adapter connected thereto. The audio system 7408 may have conventional speakers and/or directional speakers for delivering audio sounds to a first user (u-1) and a second user (u-2) located in one or more of the first room. In addition, audio output generated by the audio system 7408 may also be transmitted over a wireless channel (connection) to one or more other users in the vicinity of the wireless transmission device 7410 using the wireless audio adapter 7410. In other words, the range is determined by the type of radio channel. Generally, such ranges are relatively short, such as less than 400 meters. Thus, using the wireless channel, one or more of the third user (u-3), the fourth user (u-4) and the fifth user (u-5) can hear the audio output using a personal audio device that can receive the audio output from the wireless channel. As shown in fig. 53, the fifth user (u-5) has a personal audio device 7412 that may be attached or proximate to the fifth user (u-5). In one embodiment, a fifth user (u-5) is able to hear the audio output produced by the audio system 7408 even outdoors, such as in a backyard, while wearing the portable audio device. Thus, the personal audio device 7412 allows a remote user (e.g., u-5) to hear the audio output produced by the audio system 7408 even if he is not in the room in which the audio system 7408 is located. The remote user can hear the audio output even while he is moving as long as he is within the communication range of the wireless channel. Since the third user (u-3) and the fourth user (u-4) are not using the personal audio device, they will not hear the audio output produced by the audio system 7408 unless the audio output produced by the conventional speakers (if any) of the audio system 7408 fills the entire structural layout plan shown in fig. 53.

In one embodiment, the personal audio device may be worn by a user. Details regarding personal audio devices are described elsewhere in this patent application.

In addition to the directional limiting of the audio sounds sent to the user, the audio sounds can be further altered or adjusted according to the hearing characteristics or preferences of the user, or according to the environmental conditions of the user's immediate surroundings.

Fig. 54 is a flowchart illustrating remote control audio transmission processing 7500 according to an embodiment of the present invention. The remote audio transmission process 7500 is performed, for example, by a remote audio transmission system (e.g., remote audio transmission system 7100, 7200, or 7300).

The first step in the remote audio transmission process 7500 is to receive 7502 the audio signal using a wireless audio adapter or a wireless transmission device. However, generally, the wireless audio adapter should already be attached to the audio system that first provided the audio signal before receiving 7502 the audio signal. In summary, the audio signal received 7502 to is then wirelessly transmitted 7544 to a personal audio device. Typically, the audio signal is received wirelessly by a predetermined personal audio device. In other words, the wireless audio adapter may be configured to transmit an audio signal that is wirelessly received via a predetermined personal audio device. However, the audio signal may also be transmitted to a plurality of predetermined personal audio devices. Various methods may be employed, such as a predetermined frequency, encoding and/or network identifier (e.g., address) in order to direct such audio signals to be received by the appropriate personal audio device or devices.

After the audio signal is wirelessly transmitted 7504, the audio signal is received 7506 by the personal audio device. Here, additional processing may be performed to enhance the generated audio sounds that are ultimately transmitted to a user of the personal audio device. A decision 7508 determines whether user personalization is to be performed. When the decision 7508 determines to perform user personalization, the audio signal is adjusted 7510 according to the user information. For example, the user information may be provided through a data store, such as data store 7212 illustrated in FIG. 51.

In one implementation, the user information is associated with an audio profile associated with the user's hearing profile. In another implementation, the user information is related to the physical state of the user. Such a physical state may be detected via a sensor, which may be included in or wirelessly connected to the personal audio device. For example, if the user is sleeping, the volume of the output sound should be turned down or even turned off. Such a determination of the physical state may be performed dynamically. For example, one sensor may track the user's heart beat rhythm and determine its pattern accordingly.

After adjustment 7510, or directly after decision 7508 determines that no user personalization is to be performed, decision 7512 decides whether to perform environmental conditioning. When the decision 7512 determines that ambience adjustment is to be performed, the audio signal is adjusted 7514 according to the ambient characteristics. Such environmental characteristics may be detected or sensed by a personal audio device that includes one or more environmental sensors. For example, one or more environmental sensors can test for ambient or background noise. The environmental characteristic may also be transmitted wirelessly to the personal audio device.

After making the adjustments 7514 based on the environmental characteristics or directly after determining at decision 7512 that no environmental adjustments are to be made, the audio signal is converted 7516 to an ultrasonic drive signal. The ultrasonic drive signal is used to drive 7518 a directional speaker that outputs ultrasonic sound in a directionally limited manner. The ultrasonic sound is transmitted to the user of the personal audio device and interacts with the air such that an audio sound is produced when the sound wave output from the directional speaker reaches the vicinity of the user's head (or ear). However, since the generated ultrasonic (and thus audio) sound is directionally limited, it is delivered to the user in a targeted delivery manner. Thus, other users in the vicinity of the user will not hear any of the primary components of the audio sounds and therefore will not be disturbed.

Figure 55A is a flow diagram of an environment adaptation process 7600, according to one embodiment of the invention. The environment adaptation process 7600 determines 7602 environmental characteristics. In one implementation, these environmental characteristics may be related to the level of sound (e.g., noise) measured in the vicinity of the user. The sound level may be measured by a capture device (e.g., a microphone) in the user's vicinity. This capture device may be part of a personal audio device. In another implementation, the environmental characteristics may refer to estimated sound (e.g., noise) levels of the user's nearby surroundings. The sound level of the user's immediate surroundings can be based on the position of the user/device, from which position the sound level is estimated in the environment. The location of the user may be determined, for example, by the global positioning system GPS or network triangulation techniques. After the ambient adaptation process 7600 determines 7602 an ambient characteristic, the audio signal is adjusted according to the ambient characteristic. For example, if the area in which the user is located is full of noise (e.g., ambient noise), such as in a crowded confined space, or in a noisy building environment, the audio signals may be processed to minimize (or eliminate) unwanted noise, and/or the audio signals (e.g., in a desired frequency range) may be amplified. In the case of amplification, if the noise level is too high, the audio output may not be amplified because the user may not be able to safely hear the audio output. In other words, there may be a limit to the amount of amplification, and when the noise level is too high, the audio output may be negatively amplified (or even completely suppressed). Noise suppression and amplification may be achieved by conventional digital signal processing, amplification and/or filtering techniques. The environment adaptation process 7600 may be, for example, performed periodically or whenever a new audio stream comes in.

The user may have hearing profile that includes his hearing profile. Thus, the audio sounds provided to the user can be customized or personalized by changing or adjusting the audio signal according to the hearing characteristics of the user. Through customization or personalization of the audio signal, the audio output can be enhanced to benefit the user. Further details regarding hearing enhancement are described elsewhere in this patent application.

FIG. 55B is a flowchart of an audio personalization process 7620, according to one embodiment of the invention. The audio personalization process 7620 obtains 7622 audio profile (audio profile) associated with the user. The hearing profile includes information about the hearing profile of the user. For example, the hearing profile may be obtained by having the user perform a hearing test. The audio signal is then modified 7624 based on the audio profile associated with the user.

The hearing profile can be provided to a personal audio device or a directional audio delivery system that performs the personalization 7620 in various ways. For example, audio personal data may be electronically provided to the personal audio device or the directional audio delivery system over a network. In another example, the audio profile may be provided via a removable data storage device (e.g., a memory card). Additional details regarding audio profiling and personalization may be found elsewhere in this patent application.

The environment adaptation process 7600 and/or the audio personalization process 7620 may optionally be performed in conjunction with any of the processes discussed above that provide a directionally-constrained output. For example, the environment adaptation process 7600 and/or the audio personalization process 7620 may optionally be performed with any of the previously discussed embodiments 7100, 7200, 7300 of the remote audio transmission system of fig. 50, 51, or 52, or the previously discussed remote audio transmission process 7500 of fig. 54. If the remote audio transmission process 7500 shown in fig. 54 is selected, the environment adaptation process 7600 or the audio personalization process 7620 may be performed at step 7514 or step 7510, respectively.

Fig. 56A is a perspective view of an ultrasonic transducer 7700, according to an embodiment of the invention. The ultrasonic transducer 7700 may implement a directional speaker as discussed herein. The ultrasonic transducer 7700 generates ultrasonic waves as applied in the discussion above.

Fig. 56B is a schematic diagram illustrating the ultrasonic transducer 7700, of which a beam 7704 is generated to output an ultrasonic wave. The beam 7704 may change its properties, such as beam width, in a variety of different ways. For further details of ultrasonic transducer 7700, see elsewhere in this patent application.

The audio system of the invention may comprise or be connected to a set-top box that comprises or may be attached to a wireless audio adapter. The set-top box allows the television to receive and decode digital television broadcast signals. Generally, the set-top box is located relatively close to the television.

Fig. 57 is a perspective view of an audio system that provides directional audio delivery to a user of interest. The figure illustrates an audio system 7800 that includes a television 7802, a set-top box 7804, and a directional speaker 7806. The directional speaker 7806 transmits audio signals in a directionally limited manner. In addition, the direction can be controlled to limit the target distance of the audio signal to the user and the width of the audio signal. The directional speaker 7806 outputs ultrasonic sound via one emitting surface 7808. The emitting surface 7808 may contain one or more ultrasonic transducers.

Further, in one embodiment, directional speaker 7806 is mounted on set top box 7804. Directional speaker 7806 can be rotated as is the case with set top box 7804 and television 7802. Rotation of directional speaker 7806 causes a change in the direction in which the directional limiting audio signal is sent. For further information on this or other set-top boxes, see other parts of the present patent application.

In addition to incorporating the capability of selectable directional speaker 7806, audio system 7800 shown in FIG. 57 may also provide wireless audio transmission for personal audio devices using the various methods and processes discussed above. The set top box 7804 may also contain a wireless audio adapter as previously described. For example, in one embodiment, the set top box 7804 may contain a wireless transmission device 7104 (and possibly an audio system 7102). In another embodiment, the set top box 7804 may contain a wireless transmitter 7204 (and possibly an audio system 7202) that is remote from the audio transmission system 7200. A set-top box with directional speakers as shown in fig. 57 can selectively convert a traditional television to a television with an audio system with directional audio transmission (as well as wireless transmission to a personal audio device). In one embodiment, the ultrasonic beam is considered to pass to the user's ear whenever any portion of the ultrasonic beam or beam cone is in close proximity to the user's ear, such as within 7 centimeters of the ear. The beam direction need not be directed directly towards the ear, it may even be perpendicular to the ear, say propagating from the user's shoulder, substantially parallel to the user's face.

In another implementation, the audio system 7102 is stationary-meaning that the audio system 7102, although mobile, typically stays in a fixed location.

The various embodiments, implementations, and functional features of the invention described above may be used in various combinations and may be used alone. Those skilled in the art will appreciate from this description that the present invention is capable of being implemented in, or being used in, various other arrangements and instrumentalities shown in the various combinations, embodiments, specific implementations, or functional characteristics specified in the description.

The present invention can be implemented in software, hardware or a combination of software and hardware. Some embodiments of the invention may also be embodied as computer readable code on a computer readable medium. The computer readable medium is any data storage device that can store data which can be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, magnetic tape, optical data storage devices, and carrier waves. The computer readable medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

The advantages of the present invention are numerous. Different embodiments or implementations may yield different advantages.

Numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details. The description and representations are the means used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present invention.

In the foregoing description, reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or different embodiments mutually exclusive of other embodiments. Moreover, in the process flow diagrams or diagrams describing one or more embodiments of the invention, the order of the blocks is not intended to represent any particular order inherent in the invention, nor is any limitation of the invention implied.

The many features and advantages of the invention are apparent from the foregoing description. It is intended by the appended claims to cover all such features and advantages of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described in this application. Accordingly, all suitable modifications and equivalents are deemed to be within the scope of the invention.

Claims (18)

1. In an electronic device, the improvement comprising a directional speaker that generates a directionally limited audio output signal for a user and directs the audio output signal in a predetermined direction.

2. The electronic device of claim 1,

the directional speaker may be attached to clothing worn by the user;

the directional loudspeaker producing an ultrasonic signal that is transduced in air to produce an audio output signal; and

the apparatus further comprises:

a microphone; and

a base unit coupled to both the speaker and the microphone to allow a user to wirelessly communicate with a communication device using the device,

wherein,

the audio output signal generated by the speaker is directed from the wearing position of the speaker towards the ear of the user;

the device may be hands-free; and is

The directionally limited audio output signal provides enhanced privacy of the communication.

3. The electronic device of claim 1,

the device is a hearing enhancement system for a user; and

the device further comprises a microphone;

the microphone receives an audio input signal, which is converted into an ultrasonic signal;

the loudspeaker transmits the ultrasonic signal;

at least a portion of the ultrasonic signal is converted in air to produce an audio output signal;

the speaker directing the audio output signal from a wearing position of the speaker toward an ear of the user; and

one portion of the audio input signal is amplified more than another portion to enhance the user's hearing.

4. The electronic device of claim 1,

the device is a peripheral device of a computing device; and

the direction limiting audio output signal is directed in a predetermined direction for a user of the computing device.

5. The electronic device of claim 1 further comprising:

a set-top box receiving an input encoded signal and providing a decoded audio signal; and

an audio conversion circuit that generates an ultrasonic signal based on the decoded audio signal provided by the set-top box,

wherein

The device is for use in a home entertainment system;

the directional loudspeaker outputting an ultrasonic output based on the ultrasonic signal; and

at least a portion of the ultrasonic signal is transduced in air to produce an audio output signal.

6. The electronic device of claim 1 further comprising:

a conventional audio device, generates a conventional audio output signal,

wherein the electronic device receives an attribute input to select either the directional speaker or the legacy audio device to produce an audio output signal.

7. The electronic device of claim 1,

the audio output signal is in a beam;

receiving a beam attribute input by said device to determine an attribute of said audio output signal; and

the beam property may be one of the following properties: beam width, beam direction, isolation or privacy, and volume of the audio output signal.

8. The electronic device of claim 1,

receiving an audio profile associated with a user, the audio profile including at least one attribute associated with the user's hearing; and

based on the audio profile, the generated audio output signal is personalized for the user.

9. The electronic device of claim 1,

at least one characteristic relating to an environment of the device is received; and

adjusting the generated audio output signal according to the at least one environmental characteristic.

10. The electronic device of claim 1,

the device is in a remote control of an audio system;

the wireless signal from the audio system is received by the remote control device; and

at least one property of the direction limited audio output signal depends on the wireless signal.

11. The electronic device of claim 1, wherein the directionally-limited audio output signals are in a diverging beam, and the divergence of the beam is dependent upon a directional speaker having a curved surface, or a directional speaker comprising a plurality of speaker elements, in which case the directional speaker controls the phase of the output from the plurality of speaker elements with different drive signals.

12. The electronic device of claim 1,

the speaker having more than one segment to emit audio output signals, the audio output signals being in a beam; and

the more than one segment may be separately controlled for transmitting the audio output signal to influence the width or direction of the beam.

13. The electronic device of claim 1,

the audio output signal is based on an ultrasonic signal;

the audio output signal is in a beam; and

the width of the beam can be controlled by adjusting the frequency of the ultrasonic signal.

14. The electronic device of claim 1,

the audio output signal is based on an ultrasonic signal; and

the ultrasonic signal is reflected by at least two reflective surfaces before being emitted into free space as a directionally-limited audio output signal for the user.

15. The electronic device of claim 1 further comprising:

another directional speaker for generating a direction limiting audio output signal for a user and directing the audio output signal in a predetermined direction,

two of which may create a stereo effect for the user.

16. The electronic device of claim 1,

the apparatus includes a wireless receiver to receive a wireless signal from a wireless transmitter;

the wireless transmitter is in an audio system; and

the wireless signal is related to an audio signal that the audio system can directly output.

17. The electronic device of claim 1,

the device includes a wireless receiver that receives a wireless signal from a wireless audio adapter;

the wireless audio adapter transmitter is connected to an audio system;

the wireless signal is related to an audio signal that the audio system can directly output; and

the wireless audio adapter is an after-market product (after market product) of the audio system.

18. A system for enhancing an audio system, said audio system delivering audio output to an audio output terminal, said system comprising:

a wireless transmitter connected to the audio output terminal and wirelessly transmitting audio output provided by the audio system; and

a personal electronic device adaptable by a user, the personal electronic device comprising at least:

a wireless receiver capable of receiving audio output transmitted by said wireless transmitter;

a data storage for storing user information;

a controller operatively connected to said data storage and said wireless receiver, said controller operative to customize audio output by adjusting audio output received by said wireless receiver based on stored user information; and

a speaker operatively connected to the controller, the speaker generating a customized audio output signal in response to customization of audio output by the controller.

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