JP2020014197A - earphone - Google Patents

Abstract

To obtain an earphone having well-balanced acoustic characteristics between a low-range sound wave and a high-range sound wave.SOLUTION: An earphone includes: a diaphragm 14; and a sound emitting surface 10 arranged to face the diaphragm 14. The sound emitting surface 10 includes: a sound through hole 11 through which sound waves generated by vibration of the diaphragm 14 pass; and a vent hole 12. A shape of the sound emitting surface 10 is convex toward a front side in a vibration direction of the diaphragm 14. The sound through hole 11 is disposed at a peripheral side of the sound emitting surface 10 as compared with the vent hole 12. The vent hole 12 is arranged at a top side of the sound emission surface 10 as compared with the sound through hole 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an earphone.

  There are various types of earphones according to the user's taste, such as acoustic characteristics and fashionability.

  The shape of the inner ear type (also referred to as open type) is one of typical earphone shapes. The inner ear type earphone has a shape in which a housing for accommodating the diaphragm is mounted inside the auricle of the user's ear. Sound waves from the diaphragm are emitted from the plurality of sound holes toward the ear canal of the user's ear. The plurality of sound through holes are arranged on a sound emitting surface facing the diaphragm.

  The diffraction angle of a sound wave is smaller as the wavelength of the sound wave is shorter. Therefore, a sound wave in a high frequency band has high straightness. On the other hand, sound waves in the low frequency band have high diffusivity. Therefore, in the inner-ear type earphone, the sound wave in the high frequency band emitted from the sound through hole hardly causes a loss and easily reaches the eardrum of the user. On the other hand, the sound waves in the low frequency band after being emitted from the sound through hole are apt to cause a loss and hardly reach the eardrum of the user. As described above, the earbud of the inner ear type has an acoustic characteristic in which the high frequency range is more easily emphasized than the low frequency range.

  As an earphone for improving the acoustic characteristics of such an inner ear type earphone, there is a canal type earphone. The canal-type earphone includes a housing for accommodating the diaphragm, a sound conduit extending from the housing, and an earpiece disposed on the distal end side of the sound conduit. Sound waves from the diaphragm are emitted through the sound conduit toward the ear canal of the user's ear. Here, since the earpiece of the canal type earphone is mounted in the ear canal of the user's ear, the ear canal is completely closed. Therefore, canal type earphones are avoided by those who feel pressure on the ears.

  Earphones that improve the balance between low-frequency sound waves and high-frequency sound waves have been proposed (for example, see Patent Document 1). The earphone emphasizes low-range sound waves by deforming an inner-ear type shape in which high-range sound waves are more likely to be emphasized than low-range sound waves.

U.S. Pat. No. 8,971,561

  However, in the proposed earphone, sound waves from the diaphragm arranged in the housing are guided by the inner wall of the housing in a direction different from the vibration direction of the diaphragm, and are emitted from the sound through hole of the housing. That is, the earphone has a shape in which sound waves from the diaphragm are blocked by the housing. Therefore, the earphone causes loss of sound waves in a high frequency band having high straightness.

  An object of the present invention is to provide an earphone having a well-balanced acoustic characteristic between a low-range sound wave and a high-range sound wave.

  The present invention includes a diaphragm, and a sound emitting surface disposed to face the diaphragm, wherein the sound emitting surface has a sound through hole and a vent through which sound waves generated by vibration of the diaphragm pass. The shape of the sound emitting surface is convex toward the front side in the vibration direction of the diaphragm, and the sound through hole is arranged on the peripheral side of the sound emitting surface as compared with the vent hole, and the vent hole is , Is disposed on the top side of the sound emission surface as compared with the sound through hole.

  According to the present invention, it is possible to provide an earphone with a good balance between a low-frequency sound wave and a high-frequency sound wave.

It is a figure showing an embodiment of an earphone concerning the present invention, and is a perspective view of a right unit which constitutes an earphone. It is a front view of the right unit. It is a left view of the right unit. FIG. 4 is a right side view of the right unit. FIG. 3 is a sectional view of the right unit taken along line AA in FIG. 2. It is an acoustic equivalent circuit diagram of the right unit. 3 is a graph showing acoustic characteristics of the earphone.

  Hereinafter, an embodiment of an earphone according to the present invention will be described with reference to the drawings.

  The earphone outputs, for example, a sound wave (voice) corresponding to an audio signal (electric signal) from a sound source such as a portable musical sound reproducer (not shown) toward the eardrum of the user of the earphone. The earphone includes a right unit mounted on the right ear of the user and a left unit mounted on the left ear of the user.

  The configuration of the left unit is the same as that of the right unit except that it is symmetrical. Therefore, an earphone according to the present invention will be described below using the right unit as an example.

FIG. 1 is a diagram showing an embodiment of an earphone according to the present invention, and is a perspective view of a right unit 1 </ b> R of an earphone 1.
FIG. 2 is a front view of the right unit 1R.
FIG. 3 is a left side view of the right unit 1R.
FIG. 4 is a right side view of the right unit 1R.
FIG. 5 is a cross-sectional view of the right unit 1R taken along line AA in FIG.

  The right unit 1R includes a front housing 10, a rear housing 20, a cord bush 30, a sound hole 11, a vent hole 12, an electroacoustic transducer (described later), a sound hole adjusting member 11a, and a vent hole. It has an adjusting member 12a and a back hole adjusting member 17a. The front housing 10 and the rear housing 20 constitute a housing 100.

  Housing 100 houses the electro-acoustic transducer. The electroacoustic transducer outputs a sound wave corresponding to the audio signal from the musical sound reproducer. The housing 100 is configured by joining the front housing 10 and the rear housing 20 together. The inside of the housing 100 is hollow. The material of the housing 100 is, for example, a synthetic resin.

  The cord bush 30 prevents disconnection or the like due to bending of the signal line. The inside of the cord bush 30 is hollow. The signal line inputs an audio signal from the tone reproducer to the electroacoustic transducer. The signal line is inserted inside the cord bush 30. The space inside the cord bush 30 communicates with a rear space S2 (see FIG. 5) inside the rear housing 20. The material of the cord bush 30 is, for example, silicon.

  One end of the signal line is connected to the electroacoustic transducer. The other end of the signal line is connected to, for example, a musical sound reproducer if the earphone 1 is a wired type, and to a receiving circuit (not shown) for receiving an audio signal from the musical sound reproducer wirelessly if the earphone 1 is a wireless type. Connected.

  The earphone according to the present invention may have a configuration in which, for example, a portion of the housing 100 that comes into contact with the ear is covered with a silicon cover in order to enhance the wearability of the earphone of the user. Here, the cover is provided with a hole arranged at a position overlapping with the sound hole 11 and the air hole 12. As a result, when the cover is arranged to cover the surface of the front housing 10, the sound through holes 11 and the ventilation holes 12 provided in the front housing 10 are not closed by the cover. The sound holes 11 and the air holes 12 will be described later.

  The front housing 10 is an output surface (sound emitting surface) of a sound wave output from the electroacoustic transducer. The front housing 10 is arranged on the front side in the vibration direction of the diaphragm 14 (see FIG. 5) constituting the electroacoustic transducer. That is, the front housing 10 (sound emitting surface) is arranged away from the front surface of the diaphragm 14. The front housing 10 includes a sound hole 11 and a ventilation hole 12. The sound holes 11 and the air holes 12 are arranged on the front housing 10 (sound emitting surface). Sound waves output from the electroacoustic transducer are output (sound emitted) from the sound holes 11 and the air holes 12. That is, a part of the sound wave output from the electroacoustic transducer is output from the right unit 1R without being blocked by the front housing 10. Therefore, among sound waves output from the electroacoustic transducer, sound waves in a high frequency band are less likely to cause loss.

  In a side view, as shown in FIGS. 3 and 4, the shape of the front housing 10 is convex toward the front side (right side in FIG. 3, left side in FIG. 4) in the vibration direction of the diaphragm 14, that is, It has a dome shape.

  The sound hole 11 is disposed on the left side of the front housing 10 in FIG. On the other hand, the ventilation hole 12 is disposed in the front housing 10 on the right side of the paper of FIG. That is, as shown in FIG. 5, the sound through hole 11 is disposed on one end side (left side in FIG. 5) of the diaphragm 14 housed inside the housing 100 (the sound through hole 11 is Placed on one side). The ventilation hole 12 is arranged on the other end side of the diaphragm 14 (on the right side in FIG. 5) (the ventilation hole 12 is arranged on the other side of the diaphragm 14). That is, as shown in FIGS. 2 and 5, the sound through hole 11 is disposed closer to the periphery of the front housing 10 than the vent hole 12. On the other hand, the ventilation holes 12 are arranged closer to the top of the front housing 10 than the sound holes 11 are.

  As shown in FIG. 2, the front housing 10 has a convex shape (a bulb shape or a dome whose peripheral edge extends to the top) on the side where the sound through-hole 11 is arranged (left side in FIG. 2), as shown in FIG. Shape). That is, when viewed from the front, the distance from the center point of a virtual perfect circle having a diameter equal to the length of the front housing 10 in the height direction (vertical direction in the drawing of FIG. 1) to the front end on the side where the sound through-holes 11 are arranged. The length is longer than the length from the center point to the front end on the side where the ventilation holes 12 are arranged (right side in the drawing on the drawing).

  When the right unit 1R is worn on the user's ear, all or a part of the sound hole 11 is arranged inside the ear canal, and the air hole 12 is arranged outside the ear canal. That is, when the right unit 1R is attached to the user's ear, the sound through hole 11 is located closer to the external auditory meatus (the eardrum) than the air hole 12, and the air hole 12 is closer to the external ear canal (the eardrum) than the sound through hole 11. It is placed at a remote location.

  The shape of the sound hole 11 is different from the shape of the air hole 12.

  The area of the sound hole 11 is larger than the area of the air hole 12, as shown in FIG.

  The sound through hole 11 is a hole that is long in the vertical direction on the paper of FIG. On the other hand, the vent hole 12 is a hole that is long in the left-right direction on the paper of FIG. That is, the longitudinal direction of the sound through hole 11 is different from the longitudinal direction of the vent hole 12.

  In the present invention, the shape and number of the ventilation holes are arbitrary. That is, for example, the longitudinal direction of the air hole may be the same as the longitudinal direction of the sound hole. Further, the number of ventilation holes may be plural. However, even when the number of the air holes is plural, the area of the sound holes is larger than the sum of the areas of the air holes.

  Further, the shape of the sound through hole 11 is convex on the peripheral side of the front housing 10 (left side in FIG. 2).

  The differences in the shapes and sizes of the sound holes 11 and the air holes 12 described above and the differences in the arrangement positions in the front housing 10 affect the acoustic characteristics of the right unit 1R as described later. That is, the acoustic characteristics of the right unit 1R are determined according to the shape of each of the sound holes 11 and the air holes 12. That is, the shapes of the sound holes 11 and the air holes 12 are set in consideration of the acoustic characteristics of the right unit 1R. Further, as described later, the air permeability of the sound hole adjusting material 11a, the air permeability of the air hole adjusting material 12a, the air permeability of the back hole adjusting material 17a, and the like also affect the acoustic characteristics of the right unit 1R.

  The electroacoustic transducer includes a driver unit 13 and a diaphragm 14.

  The driver unit 13 vibrates the diaphragm 14 according to the audio signal input from the signal line. The driver unit 13 is fixed inside the housing 100 via the support 15. The electro-acoustic transducer is protected from external force applied to the front housing 10 by a protector 16 arranged inside the front housing 10.

  The vibration plate 14 generates a sound wave by vibrating according to the audio signal input from the signal line. The diaphragm 14 is arranged to face the front housing 10. The material of the diaphragm 14 is, for example, a synthetic resin. The diaphragm 14 is a circular plate. The diaphragm 14 includes a dome-shaped center dome and a sub-dome having an arc-shaped cross section. In the diaphragm 14, the center dome is arranged at the center, and the sub dome is arranged so as to surround the outer periphery of the center dome.

  The space inside the housing 100 is divided into two spaces by the driver unit 13. One space is a “front space S1” partitioned by the front housing 10 and the driver unit 13. The other space is a “rear space S2” defined by the rear housing 20 and the driver unit 13. The front space S1 communicates with the outside of the right unit 1R via the sound holes 11 and the air holes 12. The rear space S2 communicates with the outside of the right unit 1R via a rear hole (not shown) arranged in the rear housing 20.

  The sound wave generated by the vibration of the diaphragm 14 passes through the sound hole 11 after passing through the sound hole adjusting member 11a. Similarly, the sound wave generated by the vibration of the diaphragm 14 passes through the ventilation hole 12 after passing through the ventilation hole adjusting material 12a. Sound waves output from the front housing 10 (sound emitting surface) are constituted by sound waves that have passed through the sound holes 11 and the air holes 12.

  The material of the sound hole adjusting member 11a is, for example, a nylon mesh. The sound through hole adjusting member 11a covers the entire sound through hole 11 from inside the housing 100. In other words, the sound hole adjusting material 11 a is arranged in the sound hole 11.

  The material of the ventilation hole adjusting member 12a is, for example, a nylon mesh. The ventilation hole adjusting member 12a covers the entire ventilation hole 12 from inside the housing 100. In other words, the ventilation hole adjusting material 12 a is disposed in the ventilation hole 12.

  The back hole arranged in the rear housing 20 is covered with a back hole adjusting member 17a. The material of the back hole adjusting member 17a is, for example, a nylon mesh. The back hole adjusting member 17a covers the entire back hole from the inside of the housing 100. In other words, the back hole adjusting member 17a is arranged in the back hole.

  The air permeability of the sound hole adjusting material 11a, the air permeability of the air hole adjusting material 12a, and the air permeability of the back hole adjusting material 17a affect sound waves output from the front housing 10. That is, each air permeability affects the acoustic characteristics of the sound wave output from the right unit 1R. That is, the acoustic characteristics of the sound wave output from the right unit 1R are set by the air permeability of the sound hole adjusting material 11a, the air permeability of the air hole adjusting material 12a, and the air permeability of the back hole adjusting material 17a. Is done. In other words, the air permeability of the sound hole adjusting material 11a, the air permeability of the air hole adjusting material 12a, and the air permeability of the back hole adjusting material 17a are determined by the acoustic characteristics of the sound wave output from the right unit 1R. It is set to have desired characteristics. For example, the air permeability of the sound hole adjusting material 11a, the air permeability of the air hole adjusting material 12a, and the air permeability of the back hole adjusting material 17a are respectively different.

  The material of the sound hole adjusting material, the air hole adjusting material and the back hole adjusting material may be, for example, a nonwoven fabric such as cotton or resin. Further, the material of the sound hole adjusting material, the material of the air hole adjusting material, and the material of the back hole adjusting material may be different materials, for example.

FIG. 6 is an acoustic equivalent circuit diagram of the right unit 1R.
Each symbol in the figure is as follows.
BF: Sound pressure of diaphragm 14 Mm: Acoustic mass of air in sound hole 11 Rm: Acoustic resistance of air in sound hole 11 Ms: Acoustic mass of air in air hole 12 Rs: Acoustic mass of air in air hole 12 Acoustic resistance of air Mb: Acoustic mass of air in back hole Rb: Acoustic resistance of air in back hole Sf: Stiffness of front space Sb: Stiffness of back space

In the equivalent circuit diagram of the right unit 1R, the material and the air permeability of the sound hole adjusting material 11a and the material and the air permeability of the air hole adjusting material 12a are set so as to satisfy the following relational expression.
Rm <Rs

  FIG. 7 is a graph showing a frequency characteristic which is an example of an acoustic characteristic of the right unit 1R (earphone 1). In the figure, the horizontal axis indicates frequency, and the vertical axis indicates sound pressure.

  In the figure, (a) shows the frequency characteristics of the right unit 1R, (b) shows the frequency characteristics of the right unit 1R with the vent hole 12 closed, and (c) shows a plurality of sounds on the sound emitting surface facing the diaphragm. 4 shows frequency characteristics of a conventional inner ear type earphone in which a through hole is arranged.

  FIGS. 7A and 7C show that the sound pressure of FIG. 7A is higher than the sound pressure of FIG. 7C in the low sound range (about 500 Hz or less). That is, this figure shows that the right unit 1R improves the acoustic characteristics of the conventional inner-ear type earphone, in which high-range sound waves are more easily emphasized than low-range sound waves.

  FIGS. 6A and 6B show that the sound pressure of FIG. 7A is lower than the sound pressure of FIG. 7B in the low sound range (about 500 Hz or less). That is, FIG. 2 shows that the ventilation holes 12 of the right unit 1R play a role of reducing the low-frequency sound pressure.

  According to the above-described embodiment, the right unit 1R includes the front housing 10 (sound emitting surface) that is arranged to face the diaphragm 14. Sound waves generated by the vibration of the diaphragm 14 pass through the sound holes 11 and the air holes 12. The sound hole 11 and the air hole 12 are arranged in the front housing 10. Here, the vent 12 adjusts the acoustic characteristics of the sound wave output from the sound emitting surface, that is, the sound wave output from the right unit 1R. Further, in the right unit 1R, the sound through hole 11 is arranged inside the external auditory canal (the eardrum side) of the user from the vent hole 12. That is, the sound wave output from the sound hole 11 easily reaches the eardrum compared to the sound wave output from the sound hole 12.

  Therefore, in the right unit 1R, the size and shape of the air hole 12 with respect to the sound hole 11 or the material and the air permeability of the air hole adjustment material 12a with respect to the sound hole adjustment material 11a are determined by, for example, the aforementioned relational expression “Rm By setting to be <Rs ”, the acoustic characteristics of the sound wave reaching the eardrum of the user are adjusted. That is, the balance between the low-frequency sound wave and the high-frequency sound wave of the earphone 1 depends on the shape, material, and air permeability of the sound hole 11 and the sound hole adjusting material 11a. It is adjusted by setting the shape, material, air permeability, etc. of 12a.

  In addition, both the sound holes 11 and the air holes 12 are arranged on the front side in the vibration direction of the diaphragm 14. That is, the arrangement direction of the sound holes 11 with respect to the vibration direction of the diaphragm 14 is the same as the arrangement direction of the ventilation holes 12 with respect to the vibration direction of the diaphragm 14. In particular, the sound through-hole 11 arranged at a position close to the eardrum of the user is arranged on the front side in the vibration direction of the diaphragm 14. Therefore, sound waves from the vibration plate 14 are not easily blocked by the housing 100. That is, the loss of the sound wave in the high frequency band output from the right unit 1R is small. That is, the earphone 1 avoids the loss of sound waves in a high frequency band like the conventional earbud earphones, and has a higher frequency than the sound waves in the lower range, which is an acoustic characteristic of the conventional earbud earphones. Characteristics that are easily emphasized can be improved. In other words, the earphone 1 achieves acoustic characteristics similar to a canal-type earphone without completely blocking the ear canal as in a canal-type earphone.

  In the above-described embodiment, the right unit 1R has one sound hole 11 and one air hole 12 on the sound emission surface. Instead of this, the earphone according to the present invention may have a configuration in which a plurality of air holes are provided on the sound emitting surface for one sound hole. Even in the case of this configuration, the shape, material, and air permeability of the sound through hole and the sound through hole adjusting material can be reduced by setting the shape, material, and air permeability of the plurality of air holes as a whole. An earphone with a good balance between sound waves in the sound range and sound waves in the high range can be obtained. Here, the arrangement position of each of the plurality of ventilation holes on the sound emitting surface may be, for example, a position at the same distance from the sound through hole or a position at a different distance from the sound through hole.

DESCRIPTION OF SYMBOLS 1 Earphone 1R Right unit 10 Front housing 11 Sound through hole 11a Sound through hole adjustment material 12 Vent hole 12a Vent hole adjustment material 13 Driver unit 14 Diaphragm 15 Supporting body 16 Protector 17a Back hole adjusting material 20 Rear housing 30 Code bush 100 Housing S1 front space S2 back space

Claims (9)

A diaphragm,
A sound emitting surface arranged to face the diaphragm,
An earphone comprising:
The sound emitting surface is
Sound through holes and air holes through which sound waves generated by the vibration of the diaphragm pass,
With
The shape of the sound emitting surface is convex toward the front side in the vibration direction of the diaphragm,
The sound through hole is disposed on a peripheral side of the sound emitting surface as compared with the vent hole,
The ventilation hole is disposed on the top side of the sound emission surface as compared to the sound through hole,
An earphone characterized by the following. When the earphone is worn on the user's ear,
The sound through-hole is disposed at a position closer to the eardrum of the user than the vent.
The earphone according to claim 1. The shape of the sound emitting surface is convex on the side where the sound through-hole is arranged,
The earphone according to claim 1. The sound through hole is disposed on one end side of the diaphragm on the sound emitting surface,
The vent hole is arranged on the other end side of the diaphragm on the sound emitting surface,
The earphone according to claim 1. The shape of the sound through hole is convex on the peripheral side of the sound emitting surface,
The earphone according to claim 1. The shape of the sound hole is different from the shape of the air hole,
The earphone according to claim 1. The area of the sound hole is larger than the area of the air hole,
The earphone according to claim 1. The vent hole adjusts acoustic characteristics of a sound wave output from the sound emitting surface,
The earphone according to claim 1. A sound through hole adjusting member disposed in the sound through hole;
A vent adjusting material disposed in the vent,
With
The air permeability of the sound hole adjusting material is different from the air permeability of the air hole adjusting material,
The earphone according to claim 1.

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