KR20060042391A - Signal creative device - Google Patents

Abstract

It is an object of the present invention to provide a signal generation circuit capable of realizing high-precision signal reproduction with a simple configuration.

Image pickup means for receiving the feedback light from the optical recording / reproducing medium, image recognition means for image recognition according to the amount of feedback light received by each pixel constituting the image pickup device, and the positional relationship of each pixel; By providing signal separation means for grouping and separating signals and signal generation means for generating RF signals and reproduction control signals by using the separated signals, a signal generation circuit capable of realizing high-precision signal reproduction with a simple configuration is provided. do.

Feedback light, image pickup device, RF signal, optical recording, playback control signal

Description

Signal generating device {Signal Creative Device}

1 is a configuration diagram of an optical system in the signal generation device of the present invention.

2 is a diagram showing a main beam and a sub beam irradiated to an image pickup device in the signal generation device of the present invention.

3 is a block diagram of a signal generation device of the present invention.

4 is an enlarged view of the main beam and the sub-beam irradiated to the imaging device of the present invention for each pixel.

5 is a diagram illustrating a main beam and a sub beam radiated on a track.

FIG. 6 is a diagram showing an image pickup device in the case of receiving the feedback light from the main beam and the sub beam shown in FIG. 5.

FIG. 7 is a diagram showing the case where the main beam and the sub beam deviated from the track are irradiated.

FIG. 8 is a diagram showing an image pickup device in the case of receiving the feedback light from the main beam and the sub beam shown in FIG. 7.

9 is a diagram showing the case where the main beam and the sub beam deviated from the track are irradiated.

FIG. 10 is a diagram showing an image pickup device in the case of receiving the feedback light from the main beam and the sub beam shown in FIG. 9.

Fig. 11 is a diagram showing the relationship between the position of the objective lens in the focus direction and the feedback light.

12 is a diagram showing a case where the light receiving area corresponding to the main beam is divided into four.

FIG. 13 is a diagram showing a track width, an interval between a main beam and a sub beam, a beam diameter, and the like.

FIG. 14 is a diagram showing feedback light with respect to the image pickup device in the positional relationship as shown in FIG.

15 is a diagram illustrating a conventional optical system.

Fig. 16 is a diagram showing the relationship between the structure of a conventional light receiving element and a main beam and a sub beam.

17 is a diagram illustrating a configuration of a calculator.

18 is a diagram showing the configuration of a conventional signal generation device.

19 is a diagram illustrating an adjustment process relating to focus and tracking.

20 is a diagram showing a light receiving element compatible with DVD-RAM.

Fig. 21 shows a light receiving element corresponding to both CD and DVD.

Fig. 22 is a diagram showing an image pickup device according to the third embodiment.

23 is a configuration diagram of a signal generation device according to a third embodiment.

Fig. 24 shows the relationship between the wavelength of light and the sensitivity of a black and white type CCD.

Fig. 25 is a diagram showing the intensity distribution of reflected light in the light receiving portion in the fourth embodiment.

Fig. 26 shows the influence of crosstalk from adjacent tracks.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal generating apparatus in an optical disc recording and reproducing apparatus. In particular, a signal or RF for receiving reflected light of light irradiated onto an optical disc by an imaging device, recognizing the received information, and controlling the optical pickup. Provided is a good recording and reproducing apparatus for generating a signal, and also relates to a signal generating apparatus capable of reducing the cost required for development, manufacture and repair.

In the following, a configuration of an optical pickup and playback device and a signal generation device used for a CD (CD: Compact Disc) player will be described. 15 is a diagram for explaining a conventional optical system. As shown in this figure, the optical pickup for CD reproduction includes LD (semiconductor laser) 101, diffraction grating 102, half mirror 103, cylindrical lens 104, light receiving element 105. ), The objective lens 106 and the like.

The role of these components and the method of generating a control signal among the methods for reading out signals from the CD will be described. In the case of the three-beam method, the light irradiated from the LD 101 shown in FIG. By dividing into three beams, the half mirror 103 is inserted so that each beam is condensed in an objective lens (not shown) and irradiated onto the optical disc. 15 shows a case where the main beam is at the center of the track. The remaining two beams are placed in an out-of-position position as shown in FIG. 16 with respect to the main beam to generate a signal that controls whether or not the optical pickup is following the track.

These three beams reflected from the optical disk are reflected by the half mirror 103, change the direction of travel, and are incident on the cylindrical lens 104, are focused, and then enter the light receiving element 105. do. FIG. 16 shows the configuration of the light receiving element 105 shown in FIG. 15, and FIG. 17 shows a circuit for generating a control signal from each part of the light receiving element 105. As shown in FIG. Light reflected from the optical disk is incident on the light receiving portion divided into A to F, as shown in FIG. The light incident on each of these parts is converted into an electric signal and then input to the Error signal generation circuit 174 shown in Fig. 17 to generate an FE (focus error) signal or a TE (tracking error) signal.

Next, a control method of the player equipped with the optical pickup will be described with reference to Figs.

As shown in Fig. 19, for example, when an optical disc is set in the player and the play button is pressed, the CPU 160 generates an LD ON signal for causing the LD 101 to emit light (step 101), and then, The focus actuator is driven up and down (step 102). At this time, it is determined whether or not the optical disk is set from the FE (focus error) signal and the FOK (focus OK) signal generated from the PD (light receiving means) 105 divided into four (step 103). Specifically, when the FOK signal is at the "H" level, the CPU 160 determines that the optical disk is set (step 103).

If it is determined in step 103 that the optical disc is set, a signal called an S curve is generated in the FE signal immediately after the focus of the optical disc. In the calculator 152a which generates the focus error signal, a signal from A to D shown in FIG. 16 is input among four divisions of the PD (light receiving means) 105, and calculation of (A + C)-(B + D) is performed. . The calculated signal is converted into a digital signal in the A / D (analog-to-digital converter) 156a via a VCA (Voltage Control Amplifier) 155a in which gain is set to 1 times by default.

The A / D converted signal is output to the Digital EQ (equalizer) 157a. The CPU 160 calculates the maximum amplitude of the S-curve of the FE signal (step 104), and calculates the value of the VCA 155a from the maximum amplitude of the S-curve (step 105). For example, in the case where the maximum amplitude of the S-curve is 0.7VP-P and the design target value is 2.0VP-P, since the value of 2.0VP-P is 2.86, the Sero control circuit is set so that the value of the VCA 155a becomes 2.9 times. 159 performs control (step 106).

The signal generated from the four-divided light receiving portion of the PD (light receiving means) 105 is further added (A + B + C + D) in the calculator 152c to generate an RF signal. The generated RF signal is converted into an EFM signal in the EFM circuit 154, and then is input to the A / D 156d through the VCA 155d, converted into a digital signal, and then input into the PWM circuit. The Servo control circuit 159 controls the rotation speed of the disk.

From the FE signal and the FOK signal input to the Sero control circuit 159, the Sero control circuit 159 determines the focus (step 107), and closes the focus servo (step 108). When the focus servo is closed, the spindle motor (not shown) is then rotated (step 109), and a sinusoidal signal of, for example, 1 KHz, which is the focus servo band, is generated by the signal generator, which is not shown. Inject into the loop (step 110). The Servo control circuit 159 calculates the gain at 1 KHz of the FE signal in the state where a sinusoidal wave of 1 KHz is injected (step 111), and adjusts the gain and phase of the digital EQ 157a so as to be the gain of the design target value. Control is performed (step 112).

On the other hand, the TE (tracking error) signal can be obtained from the calculation of F-E in the calculator 152b from the preceding and trailing beams of the PD (light receiving means) 105 obtained with the focus servo closed. have. As in the case of the FE signal, the Servo control circuit 159 reads out the maximum amplitude of the state where the tracking servo is opened via the VCA 155b and the A / D 156b (step 113), and the VCA ( The gain of 155b) is calculated (step 114).

The CPU 160 sets the gain obtained by the calculation to the VCA 155b to perform amplification control of the TE signal (step 115). After adjusting the vertical balance (tracking error balance) of the TE signal, the tracking servo is closed (step 116), and a sinusoidal wave of 1 KHz is injected into the tracking servo loop in the same manner as in the case of focus servo (step 117). The servo control circuit 159 performs gain adjustment while the servo is closed to control the gain and phase of the digital EQ 157b (step 118).

As described above, for example, in the case of the three-beam system, the error signal used for the focus servo is based on the focus error signal generated by calculation from four light receiving sections of the light receiving means 105, and the optical pickup is performed on the optical disk surface. And an error signal used for tracking servo based on a tracking error signal generated by calculating from four light receiving units of the light receiving means 105 using a sub-beam, and performing optical pickup to a track in the optical disc. Control to follow.

Further, for the purpose of simplifying the configuration for reading information from the optical disc as described above, a recording information image of a predetermined area including a pit, which is an optical reading-capable information recording area formed on the recording surface of the optical disc, is picked up and stored, On the basis of this image data, a technique for obtaining pit length information including the length and interval of a pit on an optical disc and generating a virtual read signal corresponding to the pit read signal based on this information is disclosed (e.g., Japan Patent Publication No. 2001-202626).

However, as described above, in order to accurately control the focus and tracking by the conventional method, it is necessary to precisely adjust the position of the light receiving means at the time of assembling and adjusting the optical pickup. In the conventional example, the reproduction of the CD-ROM has been described. However, in the case of reproducing the DVD-RAM, for example, twelve light receiving means as shown in Fig. 20 are required.

Furthermore, when a laser having two different wavelengths in one case, for example, a wavelength of 780 nm for CD playback and a wavelength of 650 nm for DVD playback is constituted, as shown in FIG. For the main beam of, two elements in which D is divided into A1 to D1 and A2 to D2 by the light receiving means A are required.

As described above, when an optical disc or LD of a new format is introduced, the conventional method has a problem that it is necessary to develop a new light receiving means in accordance with these methods. In addition, in order to accurately install the light receiving means at the time of assembly adjustment, there was a problem that the number of steps during assembly increases as the accuracy is required. In addition, at the time of shipment, the installation state of the components constituting the optical pickup is precisely adjusted. However, depending on the use situation, there is a problem such that the installation position is shifted due to factors such as vibration, temperature, and humidity.

In addition, the method described in Japanese Patent Laid-Open No. 2001-202626 is a method of acquiring a shape of a pit by image data and thereby forming a similar EFM signal. In this method, a high-precision imaging device is used to increase the accuracy. In addition to the need for a memory for storing the acquired data, there has been a problem that complicated signal processing is required.

In the present invention, in view of the above-described problems, the optical receiver receives a feedback light from an optical pickup, image recognition of the received signal, and a desired signal to generate a desired signal. It is an object of the present invention to provide a signal generation circuit capable of realizing signal reproduction.

The invention according to claim 1 includes an image pickup device for receiving feedback light from an optical recording / reproducing medium, signal separation means for grouping and separating feedback light received by each pixel constituting the image pickup device, and the separated signal. Has proposed a signal generation device having a signal generation means for generating an RF signal and a reproduction control signal.

According to the present invention, the image pickup device receives the feedback light from the optical recording and reproducing medium, and the image recognition means recognizes it as an image according to the received feedback amount of each pixel and the positional relationship of each pixel. The signal separating means groups the image-recognized feedback light, and based on the grouped signals, the signal generating means generates the RF signal and the reproduction control signal.

The invention according to claim 2 proposes a signal generation device with respect to the signal generation device according to claim 1, comprising a wavelength discrimination means for discriminating the wavelength of the feedback light received by the imaging device.

According to the present invention, the image pickup device has a wavelength discrimination means for discriminating the wavelength of the feedback light received, so that a desired signal can be generated when an optical recording medium having a different wavelength of the laser used is used.

According to the third aspect of the present invention, in the signal generating apparatus according to claim 1 or 2, an A / D converter for converting the amount of feedback light received by the imaging device into a digital signal, and storage means for compressing and temporarily storing the digital signal. It is proposed a signal generating device having a.

According to this invention, since the A / D converter converts the amount of feedback light received by the imaging device into a digital signal, the following signal processing becomes easy. In addition, since the storage means compresses and temporarily stores the digital signal, it is possible to prevent a significant increase in the memory capacity.

In the invention according to claim 4, in the signal generating apparatus according to any one of claims 1 to 3, the image pickup device receives feedback light divided into two or more from the optical recording / reproducing medium, and generates the signal. The means proposes a signal generation apparatus characterized by generating a tracking control signal based on a signal grouped by two or more by said signal separation means.

According to the present invention, since the signal generating means generates the tracking control signal based on the signals grouped in two or more by the signal separating means, it is possible to generate the tracking error signal by the three-beam method conventionally employed in CD and the like. Can be.

In the invention according to claim 5, in the signal generating apparatus according to any one of claims 1 to 3, the image pickup device receives a 1-beam feedback light from the optical recording / reproducing medium, and the signal generating means And a signal generating apparatus for generating a tracking control signal based on the signal output by the signal separating means.

According to the present invention, since the image pickup device receives the 1-beam feedback light from the optical recording and reproducing medium, the signal generating means generates the tracking control signal based on the signal output by the signal separating means. The tracking error signal can be generated by the one-beam method employed in, CD and the like.

According to the invention according to claim 6, in the signal generating apparatus according to any one of claims 1 to 3, the image recognition means predicts the shape of the spot irradiated to the optical recording / reproducing medium from the imaged information. And a shape predicting means for generating predictive shape information, wherein the signal generating means generates at least one of a control direction or a control amount of the reproduction control signal based on the predictive shape information. The signal generating device according to any one of claims 3 to 9.

According to this invention, the shape of the spot is predicted by the shape predicting means, and the signal generating means generates at least one of the control direction or the control amount of the reproduction control signal based on the predicted shape information. Therefore, this makes it possible to accurately generate the focus error signal by the astigmatism method.

According to the invention according to claim 7, in the signal generation device according to any one of claims 1 to 3, the object is moved up and down with respect to the optical recording and Image information discrimination means for discriminating image information which becomes the maximum area for at least one spot based on the image information grouping the feedback light, image storage means for storing the discriminated image information, and the track information from the stored image information. The maximum number of pixels for recognizing that light is being irradiated in the advancing direction is determined, the maximum appearance of the spot is determined, the center of the spot is determined from the maximum appearance, and the spot is divided into a plurality of areas. A signal generation apparatus is proposed which has a spot area dividing means of one.

According to this invention, the image information discriminating means discriminates the image information which becomes the maximum area with respect to at least 1 spot based on the image information which grouped the returned light which was recognized image. This information is stored in the image storage means, and the first spot area dividing means discriminates the maximum number of pixels which recognizes that light is being irradiated in the traveling direction of the track from the stored image information, The center of the spot is determined from this maximum outline, and the spot is divided into a plurality of areas.

According to the eighth aspect of the present invention, in the signal generating apparatus according to any one of claims 1 to 3, detection means for detecting the maximum area of the feedback light in the image pickup device and the direction of travel of the track from the detected maximum area. Spot outline detection means for detecting the maximum number of pixels recognized as being irradiated with light on the basis of the maximum number of pixels, and at least one based on the output from the signal separation means; The maximum number of pixels recognized to be irradiated with light in the track traveling direction for the two spots and the maximum number of pixels in the track width direction are determined, the center of the spot is determined, and the spot is divided into two or more areas. The scene according to any one of claims 1 to 3, further comprising a second spot area dividing means. Proposals for arc generators.

According to the present invention, the detection means for detecting the maximum area of the feedback light, the spot outline detection means, and the spot area dividing means determine the center position of the spot on the image pickup device based on the output from the signal separation means, and the feedback light. This irradiated area can be divided into four areas. Therefore, by using this information, it is possible to accurately generate the focus error signal by the astigmatism method.

The invention according to claim 9 is characterized in that, for the signal generation device according to claim 3, the sampling frequency of the A / D converter uses a frequency clock or a frequency division of the channel clock or sampling frequency of the optical recording / reproducing medium. A signal generator is proposed.

According to the present invention, the desired frequency required for the recording / reproducing apparatus can be obtained by directly processing the obtained digital data from the sampling frequency being the frequency division or the frequency distribution of the channel clock of the optical recording / reproducing medium.

Embodiment

1 to 14 and 22 to 26, the signal generation device of the present invention will be described in detail below.

Example 1

As shown in FIG. 1, the optical system of the optical pickup constituting a part of the signal generating apparatus of the present invention includes the LD 101, the diffraction grating 102, the half mirror 103, the cylindrical lens 104, and the imaging device ( 107). As shown in Fig. 3, the circuit portion of the signal generation device includes an A / D 170, an image recognition circuit 171, a ROM 172, a RAM 173, an error signal generation circuit 174, and an LPF ( 153, EFM 154, PLL 164, A / D (155a, 155b, 155c, 155d), VCA (156a, 156b, 156c, 156d), Digital EQ (157a, 157b, 157c, 157d) and PWM 158, the servo control circuit 159, the APC 161, and the CPU 174.

For example, as shown in FIG. 2, the imaging device 107 uses a 350,000 pixel CCD or CMOS. Light reflected from the optical disk is incident on each pixel constituting the image pickup device 107 as shown in FIG. Light incident on each pixel of the image pickup device 107 is converted into an electrical signal and binarized in the A / D 170. As the sampling frequency in the binarization in the A / D 170, for example, a frequency division frequency or a frequency distribution such as 16.9344 MHz, which is a fundamental frequency of the CD-Audio reproducing apparatus, is used. The information secondary to the A / D 170 is stored in the RAM 173 via the image recognition circuit 171.

Next, the method of image recognition of the information stored in RAM is demonstrated using FIG.

For example, in the three beam system, the light returned from the optical disk is divided into one main beam and two sub beams as shown in FIG. In the conventional example, the main beam is structured so as to be irradiated to the center of the four-segment light-receiving unit, and the optical axis or the like is adjusted at the time of adjustment, and at the time of reproduction of the optical disc, the main beam is divided into four-light-receiving units by the tracking servo. Control was carried out to irradiate to the center of. On the other hand, the present invention is characterized in that three beams are received by one imaging device without dividing the light receiving portion as in the main beam and the sub beam.

Specifically, first, a portion where light is incident from the entire light receiving portion of the imaging device 107 is found. Here, the determination of whether or not light is incident on each pixel is performed by, for example, whether or not light is incident on an area of 50% or more of the pixel with respect to each pixel. This will be described based on FIG. 4. In addition, FIG. 4 enlarges only the periphery which a returned light injects for convenience of description, and shows the structure of 32 = 512 pixels.

That is, in Fig. 4, when the row direction of 32 = 512 pixels is sequentially set from 1 to 32, and the column directions are sequentially set from A to P, in this example, A5 to A6, B3 to B8, C2 to C9, and D2 to D9, D16, E1 to E10, E14 to E19, F2 to F9, F13 to F19, G2 to G9, G12 to G20, H2 to H9, HI2 to H20, H25 to 30, I3 to I8, I12 to I20, I24 to Light is incident on pixels of I31, J12 to J20, J24 to J31, K13 to K19, K24 to K31, L14 to L19, L23 to L32, MI6, M24 to M31, N24 to N31, O25 to O30, and P28. Determine.

Next, when the positional information of the obtained image is continuous in the transverse direction or the longitudinal direction, for example, these are grouped into one group. As a result, the main beams, the subbeams 1, and the subbeams 2 are determined and stored in the RAM 173 temporarily by finding and grouping three groups.

In the example of Fig. 4, as a result of the determination, the main beams of D16, E14 to E19, F13 to F19, G12 to G20, H12 to H20, I12 to I20, J12 to J20, K13 to K19, L14 to L19, M16 It is determined that the light is incident on the pixel, and the sub beams are A5 to A6, B3 to B8, C2 to C9, D2 to D9, E1 to E10, F2 to F9, G2 to G9, H2 to H9, I3 to I8, and H25 to It is determined that the light is incident on the pixels of 30, I24 to I31, J24 to J31, K24 to K31, L23 to L32, M24 to M31, N24 to N31, O25 to O30, and P28.

In the actual three-beam method, when the main beam is correctly controlled for the track, as shown in FIGS. 5 and 6, the reflected light is obtained from the main beam and the sub-beams, and when the main beam is shifted from side to side, FIG. 7. In FIG. 10, reflected light is obtained from the main beam and the sub beam.

Next, a method of generating each control signal or the like from the image recognized information will be described with reference to FIGS. 3 and 6.

In the case of generating each control signal or the like from the image recognized information, for example, a weighting computation is performed by a light quantity computing unit (not shown) in the image recognition circuit 171 with respect to the light quantity of each spot in FIG. 6. do. That is, in the example of FIG. 6, for example, the case where light is incident on all of the pixels (about 65 pixels in FIG. 6) corresponding to one spot corresponds to a voltage of 2Vp-p. The number of incident pixels is determined (50 pixels in the example of FIG. 6). Similarly, the number of pixels that enter the sub beam 1 and the sub beam 2 is also determined (in the example of FIG. 6, all 30 pixels). And from these values, the voltage of each spot is computed according to the following formula.

Subbeam (1) 30 = 0.92 VP-P

Main beam 50 = 1.54 VP-P Subbeam (2) 30 = 0.92 VP-P

Of the calculation values described above, the calculation value of the sub-beam 2 from the calculation value of the sub-beam 1, for example, by the existing three-beam method from the value of the sub-beam 1 and the value of the sub-beam 2. The TE (track error) signal is generated by subtracting.

Next, the astigmatism method will be described as an example of the method for generating the FE (focus error) signal.

11 shows the returned light in the image pickup device 107 in accordance with the positional relationship between the objective lens 106 and the optical disk. As shown in Fig. 11, when the main beam is in focus, the main beam is positioned at the position where the main beam of Fig. 4 is irradiated, and E14 to E19, F13 to F19, G12 to G20, H12 to H20, and I12 to It is determined that light is irradiated to the pixels of I20, J12 to J20, K13 to K19, and L14 to L19.

When the objective lens 106 is close to the optical disk, light is emitted to the pixels E13 to E14, F13 to F16, G13 to G17, H14 to H18, I14 to I18, J15 to J19, K16 to K19, and L18 to L19. It is determined that it is being investigated. On the other hand, when the objective lens 106 is far from the optical disk, light is emitted to the pixels E18 to 19, FI6 to F19, G15 to G19, H14 to H18, I14 to I18, J13 to J17, K13 to K16, and L13 to L14. It is determined that this is investigated.

Therefore, when the optical disk is set in the recording / reproducing apparatus and the focus search operation up-downs the objective lens 106, the above information is acquired, and the longitudinal direction (left and right direction in FIG. 11) and the height direction (vertical direction in FIG. 11) are acquired. Is calculated from the information recognized by the image recognition circuit 171. Specifically, in the example of Fig. 11, the maximum value in the longitudinal direction is selected from G12 to G20, H12 to H20, I12 to 120, and J12 to J20, and in the height direction, F14 to L14 (F14, G14, H14, I14). , J14, K14, L14. Hereinafter, the same description will be made.), F15 to L15, F16 to L16, FI7 to L17, and F18 to L18 are selected. From this result, the center in the longitudinal direction and the center position in the height direction are calculated.

The calculation method is obtained, for example, from the average of the above information (if there is five rows of information, 嘆 5.5). In the example of FIG. 11, the center in the longitudinal direction is determined by 16 columns F16 to LI6, and the center in the height direction is determined between the rows H12 to H20 of H and the rows I12 to I20 of I. From this determination result, as shown in Fig. 12, the area of the main beam is virtually divided into four areas A to D, and a voltage value is calculated for each area (in addition, information over two areas is, for example, 0.5). To be calculated). Therefore, as shown in Fig. 12, when the optical disk is in focus, it is calculated as follows.

Main beam (A) 15 VP-P = 0.46 VP-P Main beam (B) 15 VP-P = 0.46 VP-P

Main beam (C) 15 VP-P = 0.46 VP-P

Main beam (D) 15 VP-P = 0.46 VP-P

Therefore, when the optical disk is in focus, when the objective lens is close to the optical disk, (A + C)-(B + D) using the values of the main beams A, B, C, and D for the distant case. The FE (Focus Error) signal is generated by performing the operation of.

As described above, since the feedback light from the optical disk is received by the image pickup device and grouped into spots by image recognition to generate servo control signals, a new standard for recording and playback apparatuses equipped with the signal generation device of the present invention is provided. In the case where an optical disc or an optical disc corresponding to the conventional high speed recording is produced, there is no need to develop a light receiving element.

In addition, in the related art, it was necessary to precisely organize and adjust the center position of the light receiving element in accordance with the optical axis of the feedback light. However, in the present invention, there is no need for precisely adjusting the center position of the image sensing element, and the area of the image sensing element can be reduced. It is designed to be 20% larger than a wide range, and the mounting position of the image pickup device can be determined at the time of designing the base of the optical pickup, for example, by mounting it at an angle. No fine adjustment is necessary.

Example 2

Next, a second embodiment of the signal generating apparatus of the present invention will be described with reference to Figs.

In the first embodiment shown in Figs. 5 to 10, all the spots are accurately placed on the track and the so-called on-track state is explained, but Fig. 13 shows a case where a part of the spot is missed from the track, The second embodiment relates to a method applied in this case. In addition, since the discrimination process regarding which pixel of an element is incident light is the same as that of Example 1, detailed description is abbreviate | omitted.

5, 6, etc. of the first embodiment, for explaining the principle for recognizing the spot of the present invention, the position of the spot, etc. are simplified and explained, but the position of the spot corresponding to the actual optical disk is as shown in FIG. For example, in the case of CD, the spot diameter of the beam is about 1.4 m, and in the case of DVD, 0.9 m. In addition, the width of each track of the CD is about 0.5 m to 0.8 m, and the sub beam is about 16 m to 20 m away from the main beam, for example.

Further, the shortest length of the pit is 0.87 mu m and the longest pit length is 3.18 mu m when the linear velocity of the optical disk is 1.25 m / s. When the spot is irradiated to the track as shown in FIG. 13, the element is irradiated to each element as shown in FIG. 14 on the imaging device 107. In the shortest pit length, the longest pit length, and the beam diameter, and the interval between the main beam and the sub beam, since one beam does not take two pit simultaneously, each spot is grouped as in the first embodiment. By doing so, the light incident on the image pickup device 107 can be separated into three of the main beam and the sub beams 1 and 2.

In the case of Fig. 14, the tracking error is weighted and computed to generate a control signal, as in the first embodiment, by weighting pixels determined to be incident as the sub-beams 1 and 2. As for the main beam, since the columns of F103 to K103 and the columns of F104 to K104 are missing, the center of the main beam cannot be discriminated in this state, and the main beam cannot be divided into four accurately.

Here, in the second embodiment, for example, when the optical disc is set in the recording / reproducing apparatus, at the same time as rotating the optical disc, the focus actuator is moved up and down, and the information received by the image pickup device 107 is imaged. By recognizing, the information of the largest area of the image is determined and stored in the RAM 173 (hereinafter referred to as image information 1).

In addition, as described in the first embodiment, the feedback error incident on the image pickup device, except for the focusing point position, does not become a circle, and as shown in FIG. 11, an ellipse is formed. Therefore, the maximum pixel value (in the left and right directions in FIG. 11) of the information corresponding to the track travel direction and the maximum pixel value (in the up and down direction in FIG. 11) of the information corresponding to the track width direction are determined from the stored information. It is stored in the RAM 173.

Since the maximum pixel value of the information corresponding to the advancing direction of the track at the time of combining the main beams and the maximum pixel value of the information corresponding to the track width direction are known from the stored information, The center position is obtained from the outline as in the first embodiment, and the division positions to be divided into four areas A to D are calculated and stored in the RAM 173 as shown in FIG.

When image information (hereinafter referred to as image information 2) relating to the main beam of FIG. 14 is obtained, the image information 2 is compared with the image information 1 stored first. The image recognition processing circuit 171 determines which part corresponds to which part. That is, in the case of Fig. 14, the obtained spot is determined as the right part of the largest circle in Fig. 14, and is divided into four areas A to D based on the divided position stored in the RAM 173, The pixel to which light is irradiated is weighted in each area, and the error signal generation circuit 174 generates a focus error signal.

As described above, when the optical disc is set in the recording / reproducing apparatus, the objective lens is moved up and down in the focusing direction while the optical disc is rotated, the feedback light of the optical pickup is received by the image pickup device, and the image is recognized to group spots. At the same time, the maximum number of pixels in the advancing direction of the track and the maximum number of pixels in the track width direction are determined so as to store the divided position information of the main beam. In the recording / reproducing device equipped with the optical pickup of the present invention, the spot can be accurately divided to generate a focus control signal.

Example 3

Next, a third embodiment will be described.

In the embodiments described so far, a method of generating various control signals by calculating the shape of the feedback light, the center thereof, and the like irradiated to the imaging device 107 has been described. In this case, since the imaging element 107 to be used can only discriminate whether light is incident on each pixel, it may be a monochrome imaging element, for example. In the present embodiment, the image pickup device 107 is characterized in that the wavelength is determined using an image pickup device of primary color RGB, for example, or the wavelength is determined by sensitivity.

The configuration of the optical pickup in the present embodiment is basically the same as that in Fig. 1, and differs in that an image pickup device for RGB color is used for the image pickup device 107. In addition, since the CDD of the primary color filter method is used in a digital camera or the like, detailed description thereof will be omitted.

The configuration of the image pickup device and signal generation circuit to be used will be described with reference to FIGS. 22 and 23.

As shown in Fig. 22, in the image pickup device (light receiving means) 200 of this embodiment, an area having a primary color filter is provided at least in part of the image pickup device. In FIG. 22, H16, H17, I16, and I17 correspond to this area. In the example of FIG. 22, for example, each filter is "R" for H16, "G" for H17, "B" for I16, and "R" for I17.

In general, in the case of a DVD and a Blu-ray player, the LD (laser diode) uses a red DVD having a wavelength of about 650 nm and a blue purple color having a wavelength of about 405 nm in a Blu-ray. As described above, since the LD color is different due to the LD wavelength difference, a laser of a certain wavelength is irradiated onto the imaging device 200 from light incident on the area having the RGB primary color filter provided in the imaging device 200. The wavelength discrimination circuit 201 detects whether or not. In the present embodiment, an example in which each pixel has a filter of a specific color has been described, but a method of varying the color of the filter of each pixel may be used in a time division method.

Next, a method of determining the wavelength without using the filter will be described.

An example of the sensitivity with respect to the light wavelength of a monochrome type CCD is shown in FIG.

In the example of FIG. 24, the laser light has a wavelength of 405 nm for Blu-ray, the sensitivity is about 0.62, 0.75 for a laser light with a wavelength of 650 nm for DVD, and 0.4 for a laser light having a wavelength of 780 nm for CD. It can be seen that the sensitivity occurs depending on the wavelength of light.

Therefore, when the LD of each wavelength is irradiated to the mirror part of a disk, for example, when the same light quantity is designed to return to the imaging element 200 which is a light receiving means, when the sensitivity of the laser beam of wavelength 780 nm is set to 1, In 650 nm laser light, the sensitivity of 1.875 times and 405 nm laser light is 1.55 times. Therefore, the sensitivity of the laser light of 405 nm is, for example, the luminance of the pixel to which the feedback light is irradiated. By storing at 172 and comparing the sensitivity of the laser beam actually incident on the specific pixel with this, each wavelength can be discriminated. In the embodiment, the case where the CCD is used as the image pickup device has been described. The same effect can be obtained even when the image pickup device in CMOS is used.

Example 4

Next, a fourth embodiment will be described with reference to FIGS. 25 and 26.

In the first embodiment and the second embodiment, a method of generating a control signal using the three-beam method has been described. In this embodiment, the generation of a tracking error signal using the push-pull method will be described. In addition, since the push pull method itself is well-known, detailed description is abbreviate | omitted.

For example, when a laser is irradiated to a DVD-ROM disc, as shown in FIG. 25, the intensity distribution of the reflected light from the disc is asymmetrical in the light receiving portion divided into two parts due to the diffraction caused by the disc groove. It is known to become. It is the push-pull method that generates a control signal by detecting the difference in the intensity distribution. (Ref. # 2000.11 @ Shinichi Tanaka, supervision of Kazuo Shigematsu, "DVD-RAM technology", Trichet Inc., P76-80)

In general, however, it is known that crosstalk from adjacent tracks leaks into the diagonal as shown in FIG. Since the crosstalk component affects the quality of the generated tracking error signal, for example, a method of dividing the light receiving unit and deleting the crosstalk component has been proposed. (Reference: JJAP 2003 Vol. 4 No. 2B'P908-911, `` One Beam Optical Head for High-Density Optical System with Eight Segment Photodiode '' Choung Sam CHUNG et al., Samsung Electronics, Digital Media r & D Center)

In the present embodiment, since an image pickup device composed of a plurality of pixels is used in the light receiving portion, it has the same effect as in the case of dividing the light receiving portion as a result. Therefore, by eliminating only the crosstalk from adjacent tracks, which is a problem when generating a tracking error signal by the push-pull method, such signal components can be deleted from each spot, and a high quality tracking error signal can be generated. have.

As mentioned above, although embodiment of this invention was described above with reference to drawings, the specific structure is not limited to these embodiment, The design change etc. of the range which do not deviate from the summary of this invention are included. For example, in the present embodiment, the generation of the servo control signal has been mainly described. However, the present invention can also be applied to the generation of the tilt detection signal. Incidentally, in the present embodiment, the signal generating apparatus of the present invention is referred to as a case of applying to an actual recording / reproducing apparatus of an optical disc, but for example, the signal generating apparatus of the present invention is applied as a tool for component development. You may.

According to the present invention, the feedback light of the optical pickup is received by the image pickup device, the image is recognized, the spots are grouped, and the control signal for the servo is generated. Therefore, the present invention relates to a recorder equipped with a signal generator. In the case where an optical disc of a new standard or an optical disc corresponding to high-speed recording appears more than the conventional one, there is an effect that it is not necessary to develop a new light receiving element.

In addition, in the past, it was necessary to precisely organize and adjust the center position of the light receiving element in accordance with the optical axis of the feedback light. However, in the present invention, an operation such as accurately matching the center position of the image pickup element is not necessary, and the area of the image pickup element is reduced. Since it is designed to be 20% larger than a wide range, and the mounting position of the image pickup device can be determined by an operation such as attaching it to each part provided in the case or the like in advance when designing the base of the optical pickup, There is an effect that high precision adjustment such as is unnecessary.

Further, when the optical disc is set in the recording / reproducing apparatus, the objective lens is moved up and down in the focusing direction while the optical disc is rotated, and the spots are grouped by receiving the pick-up light of the optical pickup by the image pickup device and recognizing the image. Since the image to be the number of pixels, the maximum number of pixels in the travel direction of the track and the maximum number of pixels in the track width direction are determined to store the divided position information of the main beam, even when the spot is not caught by the track, the present invention In the recording / reproducing device equipped with the signal generator, the spot can be divided accurately so that the control signal of the focus can be generated.

Claims (9)

An image pickup device for receiving feedback light from an optical recording / reproducing medium; Image recognition means for recognizing the image according to the feedback amount received by each pixel constituting the imaging device and the positional relationship of each pixel; Signal separation means for grouping and separating the image-recognized feedback light; And And a signal generating means for generating an RF signal and a reproduction control signal by using the separated signal. The method of claim 1, And a wavelength discriminating means for discriminating the wavelength of the feedback light received by the image pickup device. The method according to claim 1 or 2, An A / D converter for converting the feedback light received by the imaging device into a digital signal; And a storage means for compressing and temporarily storing the digital signal. The method according to any one of claims 1 to 3, The image pickup device receives the feedback light divided into two or more from the optical recording and reproducing medium, and the signal generating means generates a tracking control signal based on the signals grouped into two or more by the signal separating means. Signal generating device, characterized in that. The method according to any one of claims 1 to 3, The image pickup device receives a 1-beam feedback light from the optical recording and reproducing medium, and the signal generating means generates a tracking control signal based on the signal output by the signal separating means. . The method according to any one of claims 1 to 3, The image recognition means has shape prediction means for predicting and calculating the shape of the spot irradiated to the optical recording / reproducing medium from the imaged information, and generating predictive shape information. And at least one of a control direction or a control amount of the reproduction control signal. The method according to any one of claims 1 to 3, When the objective lens is set up, the image information is moved up and down with respect to the optical recording and reproducing medium, and at the same time, the image information becomes the maximum area for at least one spot based on the image information in which the image recognized feedback light is grouped. Image information discriminating means for discriminating; Image storage means for storing the discriminated image information; And From the stored image information, the maximum number of pixels recognized as being irradiated with respect to the traveling direction of the track is determined, the maximum appearance of the spot is obtained, and the center of each spot is determined from the maximum appearance, and the spot is determined. And a first spot area dividing means for dividing into a plurality of areas. The method according to any one of claims 1 to 3, Detection means for detecting a maximum area of feedback light in the imaging device; Spot outline detection means for detecting the maximum number of pixels recognized as being irradiated with light in the traveling direction of the track from the detected maximum area and detecting the maximum appearance of the spot from the maximum number of pixels; And Based on the output from the signal separating means, the maximum number of pixels recognized as being irradiated to the track traveling direction with respect to at least one spot and the maximum number of pixels in the track width direction are discriminated to determine the center of the spot. And a second spot area dividing means for dividing the spot into two or more areas while discriminating. 4. The signal generating apparatus according to claim 3, wherein the sampling frequency of the A / D converter uses a channel clock or a frequency divided by a sampling frequency of the optical recording / reproducing medium.

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