JP4103852B2 - Optical disc apparatus and control method thereof - Google Patents

Description

  The present invention relates to an optical disc apparatus for recording / reproducing information on an optical disc by an optical pickup and a control method thereof.

  As optical disc devices, audio CDs, CD-ROMs, CD-R / RWs, DVDs, and the like have already been put into practical use, and application to various fields and development for high performance are being actively conducted. . Particularly recently, along with the rapid market expansion of personal computers, the penetration rate of built-in optical disk devices in personal computers has increased.

  Here, the configuration of the optical disc apparatus will be described with reference to FIG.

  FIG. 7 is a block diagram of the pickup control unit of the optical disc apparatus. In FIG. 7, 1 is an optical disk, 2 is a pickup module, 3 is a spindle motor, 4 is an optical pickup, 5 is a carriage, 6 is a feed unit, 7 is a feed motor, 8 is an analog signal processing unit, 9 is a servo processing unit, Reference numeral 10 denotes a motor driving unit, 11 denotes a digital signal processing unit, 12 denotes a laser driving unit, and 13 denotes a controller.

  The operation of the pickup control unit in the conventional technology configured as described above will be described. In FIG. 7, a pickup module 2 includes a spindle motor 3 that rotates an optical disc 1, an optical pickup 4 that performs at least one of reading and writing information signals on the optical disc 1, and a carriage 5 on which the optical pickup 4 is mounted. And a feed portion 6 for moving in the radial direction. The analog signal processing unit 8 generates a focus error signal and a tracking error signal based on a signal output from an optical sensor (not shown) in the optical pickup 4 in the carriage 5 provided in the pickup module 2. To the servo processing unit 9.

  The focus error signal indicates a shift in the focal direction between a light beam spot emitted from an objective lens (not shown) provided in the optical pickup 4 and the recording surface of the optical disc 1. The tracking error signal indicates a deviation in the optical disc radial direction between the light spot and the information track of the optical disc 1. The analog signal processing unit 8 extracts a low frequency component of the tracking error signal and outputs it to the servo processing unit 9. The servo processing unit 9 generates a lens position signal indicating the relative positional relationship between the objective lens and the carriage 5 and outputs the lens position signal to the motor driving unit 10.

  The servo processing unit 9 includes an ON / OFF circuit, an arithmetic circuit, a filter circuit, an amplifier circuit, and the like. The servo processing unit 9 performs focus / tracking control of the objective lens so that the light beam spot follows the information track of the optical disc 1, and further a tracking error signal. Feed control is performed so that the objective lens maintains a substantially neutral position using the low-frequency component. The feed unit 6 includes a feed motor 7, a gear (not shown), a screw shaft (not shown), and the like. The carriage 5 is moved by rotating the feed motor 7. Are output periodically. The controller 13 controls the entire servo unit configured as described above.

In order to achieve high quality and stable recording, it is necessary to accurately irradiate the laser beam in the tracking direction of the optical disc. However, the offset amount of the tracking error signal increases due to the optical axis misalignment of the optical pickup. In addition, if the amplitude of the tracking error signal during recording increases due to variations in the characteristics of optical elements in the optical pickup or amplifiers that amplify the detection signal, or changes in temperature or changes over time, the digital signal processing unit As a result, the tracking error signal is saturated, and the laser beam is not accurately controlled with respect to the optical disk. Here, the optical axis misalignment of the optical pickup is an optical misalignment caused by a mechanical position misalignment with respect to an assembly target dimension between components constituting the optical pickup, that is, the components constituting the optical pickup. Tracking error signal gain maximum processing means that a gain adjustment command is issued while offsetting a certain amount in the amplitude direction of the tracking error signal during recording, and the gain increases, that is, the tracking error signal waveform has a large slope. This is processing that corrects the offset amount of the tracking error signal by regarding this as the center of the track.

  Here, the conventional tracking control will be described with reference to FIG.

  FIG. 8A is a diagram showing a state in which a light beam is applied to a track of an optical disc, and FIG. 8B is a diagram showing a beam spot locus and a tracking error signal when the tracking error signal is saturated. It is. In FIG. 8, 14 is a light beam.

  As shown in FIG. 8A, the light beam 14 is controlled to follow the center of the track. However, when the tracking error signal is saturated in the digital signal processing unit 11 that sends a signal to the controller 13, the target track However, even if the beam spot is controlled almost accurately, the control accuracy of the controller 13 deteriorates, and the deviation of the tracking error signal (TE signal) increases as shown in FIG. If the offset amount of the tracking error signal is only large due to the optical axis misalignment of the optical pickup, etc., it is possible to follow to some extent by offset correction, but the amplitude of the tracking error signal measured during recording is further increased. When it becomes larger, the tracking error signal is saturated in the digital signal processing unit 11, the tracking tracking accuracy is deteriorated, and a tracking error occurs. In order to prevent this, it is necessary to suppress the amplitude of the tracking error signal within the dynamic range of the digital signal processing unit 11.

An example of prior art in this field is described in (Patent Document 1).
Japanese Patent No. 3257655

  Thus, unless the light beam can accurately follow the target track in the tracking direction, the recording quality cannot be maintained at a high level.

  The present invention has been made in order to solve the above-described problems. The tracking error signal is caused by variation in characteristics of an optical element such as an optical element in an optical pickup or an amplifier that amplifies a detection signal, or a temperature change or a change with time. It is an object of the present invention to provide an optical disc apparatus capable of preventing fluctuations in the amplitude of the recording medium and stabilizing the tracking servo during recording, and a control method therefor.

  The present invention is an optical disc apparatus including a control unit that performs tracking control of an optical pickup using a tracking error signal, wherein the control unit measures equivalent information of the tracking error signal amplitude and obtains the tracking The equivalent information of the error signal amplitude is compared with a predetermined threshold value, and the tracking error signal amplitude amount is changed based on the comparison result.

According to the present invention, the control unit measures equivalent information of the tracking error signal amplitude, compares the obtained equivalent information of the tracking error signal amplitude with a predetermined threshold, and based on the comparison result. Then, the tracking error signal amplitude amount is changed, and the equivalent information of the tracking error signal amplitude is obtained by measuring the slope of the tracking error signal amplitude waveform at a portion where a certain amount of offset is performed in the amplitude direction from the reference voltage. Thus , even during the recording operation, information equivalent to the tracking error signal amplitude can be obtained and the amplitude amount of the tracking error signal can be adjusted and the amplitude amount of the tracking error signal can be made constant. Variations in the characteristics of electrical elements such as amplifiers that amplify detection signals and their temperature changes Prevents the fluctuating amplitude of the tracking error signal by the aging, the tracking servo in the recording can be stabilized.

The invention according to claim 1 is an optical disc apparatus including a control unit that performs tracking control of an optical pickup using a tracking error signal, and the control unit is obtained by measuring equivalent information of the tracking error signal amplitude. said comparing the predetermined threshold value and the tracking error signal amplitude equivalent information, based on the comparison result, the change of the tracking error signal amplitude amount, the amplitude from the equivalent information is the reference voltage of the tracking error signal amplitude It is obtained by measuring the slope of the tracking error signal amplitude waveform of the part offset by a certain amount in the direction. Tracking error is obtained by obtaining information equivalent to the tracking error signal amplitude even during recording operation. since adjusting the amplitude of the signal, the optical elements and detection in the optical pickup Prevents the amplitude of the tracking error signal by the characteristic variation or their change with temperature and time of the electric element such as an amplifier for amplifying the signal from fluctuating, the tracking servo in the recording can be stabilized.

The invention according to claim 2 is characterized in that the amplitude amount changed per time by the means for changing the tracking error signal amplitude amount is constant, and the amplitude amount to be changed is made constant. The means for changing the amplitude can be simplified.

The invention according to claim 3 is characterized in that the recording gain of the tracking error signal is controlled with the predetermined threshold value being 1.1 times the control target amplitude amount as an upper limit threshold value. By setting the minimum value required for the operation stability of the tracking servo to the predetermined threshold value, both the stability of the tracking servo and the processing time can be achieved.

The invention according to claim 4 is characterized in that the recording gain of the tracking error signal is controlled with the predetermined threshold value being 0.9 times the control target amplitude amount as a lower limit threshold value. By setting the minimum value required for the operation stability of the tracking servo to the predetermined threshold value, both the stability of the tracking servo and the processing time can be achieved.

The invention according to claim 5 is characterized in that the amplitude amount changed per time of the tracking error signal is 1 to 5% with respect to the amplitude amount before the change, and the tracking error signal By setting the minimum value necessary for the operation stability of the tracking servo to the amplitude amount changed per time, both the stability of the tracking servo and the processing time can be achieved.

The invention of claim 6, wherein, there is provided a control method of an optical disk apparatus performs tracking control of the optical pickup by using the tracking error signal, to measure the equivalent information of the tracking error signal amplitude, resulting the tracking error signal amplitude Is compared with a predetermined threshold value, and the tracking error signal amplitude amount is changed based on the comparison result. The tracking error signal amplitude equivalent information is offset by a certain amount in the amplitude direction from the reference voltage. It is obtained by measuring the slope of the tracking error signal amplitude waveform of the part that has been subjected to, and even during recording operation, information equivalent to the tracking error signal amplitude is obtained to adjust the amplitude amount of the tracking error signal since, to adjust the amplitude of the tracking error signal The tracking servo during recording can be prevented by preventing fluctuations in the amplitude of the tracking error signal due to variations in characteristics of optical elements such as optical elements in the optical pickup and amplifiers that amplify the detection signal, and changes in temperature and changes over time. It can be stabilized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram of a pickup control unit of an optical disc apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a recordable optical disk, 2 is a pickup module, and the pickup module 2 is irradiated with light on a spindle motor 3 that rotates the optical disk 1 variably or at a constant rotation, and the optical disk 1. Thus, the optical pickup 4 for recording predetermined information on the optical disc 1 or reading information based on the reflected light of the light irradiated on the optical disc 1, the carriage 5 on which the optical pickup 4 is mounted, and the carriage 5 with the radius of the optical disc 1. A feed unit 6 that is driven to reciprocate in a direction and a feed motor 7 that is a drive source of the feed unit 6 are fixed, and a small / thin optical disk is realized by such a configuration.

  In the present embodiment, each of the above members is mounted on the pickup module 2. However, at least one of the members may be mounted, and the other members are mounted and fixed on a portion inside another optical disk device. Also good. 8 is an analog signal processing unit, 9 is a servo processing unit, 10 is a motor driving unit, 11 is a digital signal processing unit, 12 is a laser driving unit, and 13 is a controller.

  Here, the controller 13 constitutes a control unit of the present invention, and signals sent from the analog signal processing unit 8, the servo processing unit 9, the motor driving unit 10, the digital signal processing unit 11, and the laser driving unit 12 are input. Then, the arithmetic processing of these signals is performed, the result (signal) of this arithmetic processing is sent to each part, the driving and processing are executed in each part, and each part is controlled. Although the detailed description and illustration are omitted, it goes without saying that the controller 13 includes at least an arithmetic processing device such as a CPU and MPU having an arithmetic function and a storage device such as a ROM and RAM.

  The operation of the optical disk apparatus configured as described above according to the embodiment of the present invention will be described. In FIG. 1, a pickup module 2 moves a spindle motor 3 that rotates an optical disc 1, an optical pickup 4 for reading an information signal of the optical disc 1, and a carriage 5 on which the optical pickup 4 is mounted in the radial direction of the optical disc 1. The feed section 6 is configured.

  The feed unit 6 includes a feed motor 7, a gear (not shown), a screw shaft (not shown), and the like. By rotating the feed motor 7, the carriage 5 moves between the inner periphery and the outer periphery of the optical disk 1. It is configured.

  The analog signal processing unit 8 generates a focus error signal and a tracking error signal based on a signal output from an optical sensor (not shown) in the optical pickup 4 in the carriage 5 configured in the pickup module 2. Output to the servo processing unit 9.

  The servo processing unit 9 is an A / D converter that converts the analog signal sent from the analog signal processing unit into a digital signal, a memory that temporarily stores the digital signal converted by the A / D converter, and is recorded in the memory An arithmetic circuit that calculates a digital signal sent from an A / D converter or a digital signal sent from an A / D converter by a predetermined method, and a D / A converter that converts the digital signal calculated by the arithmetic circuit into an analog signal In addition, the filter signal processing and various calculation processes are performed by digital calculation so that the light beam spot follows the information track of the optical disc 1. For this reason, various parameter settings and sequence control can be flexibly performed by command from the controller 13.

  The servo processing unit 9 performs control for moving the objective lens mounted on the optical pickup 4 in the focus direction / tracking direction via the motor driving unit 10, transfer control for the feed unit 6, and rotation control for the spindle motor 3. Do.

  During the reproduction operation, the optical pickup 1 is irradiated with light from the optical pickup 4, the reflected light from the optical disk 1 is received by a light receiving element (not shown), and the reproduction output from the optical pickup 4 according to the received light. A signal is input to the digital signal processing unit 11 via the analog signal processing unit 8.

  The digital signal processing unit 11 includes a data slicer, a data PLL circuit, a jitter measurement circuit, an error correction unit, a modulation / demodulation unit, a buffer memory, a laser control unit, and the like, and is effective for the host (HOST in the figure) side. It is transferred as data.

During recording operation, the digital signal processing unit 11 modulates data sent from the host, and the laser control unit sends a predetermined light source such as a laser (not shown) in the optical pickup 4 via the laser driving unit 12. A current is supplied, the light source is caused to emit light in a pulse shape, for example, and recording is performed on an information track of the optical disc 1. The controller 13 controls the entire optical disk apparatus configured as described above.

  Tracking control using the tracking error signal is also performed by the controller 13. FIG. 2 is a diagram showing a tracking error signal of the optical disc apparatus according to the embodiment of the present invention. FIG. 2A is a diagram showing a tracking error signal in the tracking-on state, and the amplitude of the TE signal increases as the control position of the light beam deviates from the track center of the target track. FIG. 2B is a diagram showing a tracking error signal in a tracking-off state. Since tracking tracking is not performed, a sine wave corresponding to the amount straddling the track appears.

  Hereinafter, each part of the present invention will be described in detail.

  First, the gain control of the tracking error signal will be described.

FIG. 3 is a diagram showing a correspondence relationship between the offset and gain of the tracking error signal in the optical disc apparatus according to the embodiment of the present invention, and FIG. 3A is a diagram showing a state in which no offset occurs in the tracking error signal. FIG. 3B is a diagram illustrating a state in which an offset is generated in the tracking error signal. In FIG. 3, 15 is a reference voltage axis, 16 is a tracking signal waveform, 17 is an intersection, and 18 is a slope. Since the tracking error signal waveform 16 shown in FIG. 3A shows that no offset is generated, the center position of the tracking error signal amplitude coincides with the reference voltage axis 15 when the tracking error signal is a sine wave. To do. Also, since the tracking error signal waveform 16 shown in FIG. 3B shows a state in which an offset is generated, when the tracking signal is a sine wave, the center position of the amplitude of the tracking error signal is the same as that of the reference voltage axis 15. There is a case where the tracking error signal waveform 16 is not coincident and the tracking error signal waveform 16 is on the plus side or the minus side with respect to the reference voltage axis 15.

  The slope 18 of the tracking error signal waveform 16 at the intersection 17 of the tracking error signal waveform 16 and the reference voltage axis 15 shown in FIG. 3A, and the two tracking error signal waveforms 16 and the reference voltage axis 15 shown in FIG. 3A is larger than the inclination 18 of the tracking error signal waveform 16 at the intersection 17 of FIG. Under the condition of the same amplitude, the inclination 18 of the tracking error signal waveform 16 at the intersection 17 of the tracking error signal waveform 16 and the reference voltage axis 15 is smaller as the offset amount generated in the tracking error signal is smaller, that is, the tracking error signal waveform. The slope 18 of the tracking error signal waveform 16 at the intersection 17 of the tracking error signal waveform 16 and the reference voltage axis 15 increases as the amplitude center of 16 and the reference voltage axis 15 coincide as much as possible.

  If the gain adjustment command is issued while intentionally offsetting the tracking error signal during data recording using these phenomena, it becomes possible to find the place where the gain increases, that is, the track center, and correct the recording offset. be able to.

  Next, gain control of the tracking error signal will be described.

  FIG. 4 is a flowchart showing gain control of the tracking error signal of the optical disc apparatus according to the embodiment of the present invention. When the optical disk 1 is inserted, the optical disk apparatus rotates the spindle motor 3 to start the startup process, applies focus servo and tracking servo, and moves the objective lens 14 in the pickup module 2 to the recording area on the optical disk 1. The data recording operation is started.

  When the recording operation is confirmed by the recording operation confirming means (S1), first, the learning period recording sector number checking means (S2) first uses which mode among the several speed recording modes installed in the optical disc apparatus. The recording speed is checked to see if it has been recorded, and the number of sectors corresponding to the mode is extracted. The number of sectors is uniquely determined by the type of the double speed recording mode, and at the same time, an offset amplitude described later is also determined here.

Next, processing by various set value acquisition means (S3), tracking error (TE) signal investigation result acquisition means (S4) due to plus side offset, and tracking error (TE) signal investigation result acquisition means (S5) due to minus side offset. Do. Various setting value acquisition means (S3) acquires information on the offset amount and recording gain value of the recording mode currently in use. In the tracking error (TE) signal investigation result acquisition means (S4) due to the plus side offset, the offset is uniquely determined by the type of the double speed recording mode currently in use obtained by the learning period recording sector number check means (S2). The tracking error signal is offset in the positive direction by the amount as shown in the tracking error signal waveform 16 displaced to the plus side in FIG. 3B, and the tracking error signal at the intersection 17 of the tracking error signal waveform 16 and the reference voltage shaft 15 is detected. The slope 18 of the waveform 16 is measured. Similarly, the tracking error (TE) signal investigation result acquisition means (S5) due to the minus side offset is uniquely determined by the type of the double speed recording mode currently in use obtained by the learning period recording sector number check means (S2). The tracking error signal is offset in the positive direction by the determined offset amount as shown in the tracking error signal waveform 16 displaced to the minus side in FIG. 3B, and the intersection 17 of the tracking error signal waveform 16 and the reference voltage shaft 15. The slope 18 of the tracking error signal waveform 16 is measured.

  The tracking error (TE) signal gain value comparison means (S6) performs comparison using the information of the slope 18 of the tracking error signal waveform 16. This will be described with reference to FIG. 5 along the flowchart of FIG.

  FIG. 5 is a diagram showing gain control of the tracking error signal of the optical disc apparatus according to the embodiment of the present invention, and shows a case where the amplitude of the tracking signal is constant. In FIG. 5, 15 is a reference voltage axis, 16 is a tracking error signal waveform, 17, 19 a and 20 a are intersections, 18, 19 b and 20 b are tilts, 19 is a plus side offset axis, and 20 is a plus side offset axis. In the tracking error (TE) signal gain value comparison means (S6), the intersection 19a between the plus-side offset shaft 19 obtained by the tracking error (TE) signal investigation result acquisition means (S4) by the plus-side offset and the tracking error signal waveform 16 The waveform slope 19b and the waveform slope 20b at the intersection 20a of the tracking error signal waveform 16 obtained by the tracking error (TE) signal investigation result acquisition means (S5) due to the minus side offset are compared. . At this time, a waveform error 19b at the intersection 19a of the plus side offset axis 19 and the tracking error signal waveform 16 obtained by the tracking error (TE) signal investigation result acquisition means (S4) due to the plus side offset is a tracking error due to the minus side offset. (TE) If the slope 19b of the waveform at the intersection 19a of the plus-side offset axis 19 and the tracking error signal waveform 16 obtained by the signal investigation result obtaining means (S5) is larger than the plus-side offset correction means (S7) The tracking error (TE) signal is offset to the plus side. Tracking error (TE) due to minus side offset The waveform slope 20b at the intersection 20a between the minus side offset axis 20 and the tracking error signal waveform 16 obtained by the survey result acquisition means (S5) is the tracking error (TE) due to the plus side offset. If it is larger than the waveform slope 19b at the intersection 19a of the plus side offset axis 19 and the tracking error signal waveform 16 obtained by the signal investigation result acquisition means (S4), the tracking error (S8) is used to correct the tracking error (S8). TE) Offset the signal to the negative side. In addition, the tracking error (TE) signal obtained by the tracking error (TE) signal investigation result acquisition means (S4) by the plus side offset and the tracking error (19) at the intersection 19a of the plus side offset axis 19 and the tracking error signal waveform 16 and the tracking error due to the minus side offset ( TE) When the waveform slope 20b at the intersection 20a of the negative offset axis 20 obtained by the signal investigation result acquisition means (S5) and the tracking error signal waveform 16 is the same, no offset correction is performed and the tracking error (TE) It is sent to the signal gain average value comparison means (S9).

Next, tracking error (TE) signal gain average value comparison means (S9) and tracking error (TE) signal recording gain down means (S10) or tracking error (TE) signal recording gain up means (S11) according to the present invention. The process by is performed. If the amplitude of the tracking error signal sent from the plus side offset correcting means (S7), the minus side offset correcting means (S8), or the tracking error (TE) signal gain value average comparing means (S6) is constant. If there is a fluctuation in the amplitude of the tracking error signal due to variations in the characteristics of the optical elements in the optical pickup or amplifiers that amplify the detection signal, or changes in temperature or changes over time, tracking errors will occur. The signal is saturated in the digital signal processing unit 11, tracking tracking accuracy is deteriorated, and a tracking error occurs. Therefore, this tracking error signal gain average value comparison means (S9) adjusts the amplitude of the tracking error signal. The tracking error signal gain average value comparison means (S9) first checks the equivalent information of the tracking signal amplitude. Next, the processing is determined by comparing the equivalent information of the tracking error signal amplitude with the threshold value for performing the subsequent processing. The equivalent information of the tracking error signal amplitude can be used to estimate the amount of tracking signal amplitude by obtaining the information. In this embodiment, the tracking error signal gain value comparison means (S6) uses the tracking information. Information on the slope 18 of the error signal waveform 16 is used. If the equivalent information of the tracking signal amplitude is larger than the upper limit threshold value, it is sent to the tracking error (TE) signal recording gain down means (S10), and if it is smaller than the lower limit threshold value, it is sent to the tracking error (TE) signal recording gain up means (S11). . Here, the upper limit threshold is 1.1 times or more of the control target amplitude, and the lower limit threshold is 0.9 or less of the control target value. The upper threshold value is 1.1 times or more and the lower threshold value is 0.9 times or less is a condition necessary for stabilizing the tracking servo, and it is possible to achieve both tracking servo stability and processing time. It is. The tracking error signal sent to the tracking error (TE) signal recording gain down means (S10) exceeding the upper limit threshold is adjusted so that the gain is uniformly reduced by 1 to 5%, not limited to the value, and the recording operation confirmation means ( S1). Similarly, the tracking error signal sent to the tracking error (TE) signal recording gain increasing means (S11) exceeding the lower limit threshold is adjusted so that the gain is uniformly increased by 1 to 5%, not limited to the value, and the recording operation is performed. It is sent to the confirmation means (S1). In the present embodiment, the gain adjustment amount of the tracking error signal is changed from the amplitude amount changed per time to the amplitude amount before the change regardless of whether the upper limit threshold value or the lower limit threshold value is exceeded. On the other hand, it was uniformly 1.5%. A tracking error signal that does not exceed the upper threshold and does not exceed the lower threshold is sent directly from the tracking error signal gain average value comparison means (S9) to the recording operation confirmation means (S1). The controller 13 controls the operation from the recording operation confirmation unit (S1) to the tracking error signal gain value averaging unit (S9), the recording gain down unit (S10), or the recording gain up unit (S11). Necessary information is sent from the servo processing unit 9.

  Thus, the recording operation confirmation means (S1) to the tracking error signal gain average value comparison means (S9), the tracking error (TE) signal recording gain down means (S10), or the tracking error (TE) signal recording gain up means (S11). ) Through the loop returning to the recording operation confirmation means (S1) again, the amplitude of the tracking error signal can be made constant, so that an optical element in the optical pickup, an amplifier for amplifying the detection signal, etc. Thus, it is possible to prevent the amplitude of the tracking error signal from fluctuating due to variations in the characteristics of the electric elements, temperature changes and changes with time, and to stabilize the tracking servo during recording.

  Therefore, the tracking error signal gain average value comparison means (S9), the tracking error (TE) signal recording gain down means (S10) and the tracking error (TE) signal recording gain up means (S11) of the present invention are always during recording. Since it is possible to cope with a change with time due to temperature if it is in the ON state, it is preferable to always keep it ON during data recording.

  Next, the operation of tracking error signal gain value average (S9) and recording gain down (S10) or recording gain up (S11) according to the present invention will be described in detail with reference to FIG.

  FIG. 6 is a diagram showing gain control of the tracking error signal of the optical disc apparatus according to the embodiment of the present invention, and shows a case where the amplitude of the tracking signal is not constant but increases. In FIG. 6, 15 is a reference voltage axis, 19 is a plus offset axis, 20 is a minus offset axis, 19c, 19e, 20c, and 20e are intersections, and 19d, 19f, 20d, and 20f are inclinations.

The tracking error signal waveform 16 as shown in FIG. 6 enters the tracking error signal gain average value comparison means (S9). First, the case of the waveform A in which the tracking error signal amplitude is within the dynamic range of the digital signal processing unit 11 will be described. In the tracking error signal gain average value adjusting means (S9), first, the slope 19d of the intersection 19c of the tracking error signal waveform 16 and the plus side offset axis 19 and the slope 20d of the intersection 20c of the tracking error signal waveform 16 and the minus side offset axis 20 are set. , And an average inclination value is obtained from the obtained inclination 19d and inclination 20d. The obtained slope average values of the slope 19d and the slope 20d are compared with a predetermined threshold value for performing case classification in the subsequent processes to determine the process. In the present embodiment, the upper limit threshold is 1.1 times or more of the control target amplitude, and the lower limit threshold is 0.9 or less of the control target amplitude. These threshold values are compared with the average inclination values of the inclination 19d and the inclination 20d. If the inclination average values of the inclination 19d and the inclination 20d exceed the upper limit threshold value or the lower limit threshold value, the tracking error signal recording gain reduction means ( S10) and the tracking error signal recording gain up means (S11) to adjust the recording gain of the tracking error signal, and the recording operation confirmation means (S1) to tracking error signal gain averaging means (S9) or recording gain down means. By repeating the loop returning to the recording operation confirmation means (S1) again via (S10) or the recording gain increase means (S11), the amplitude of the tracking error signal can be made constant.

  Next, the case of the waveform B, which is a case where the tracking error signal amplitude is outside the dynamic range of the digital signal processing unit 11 or has no tolerance for the dynamic range, will be described. In the tracking error signal gain average value comparison means (S9), first, the slope 19f of the intersection 19e of the tracking error signal waveform 16 and the plus side offset axis 19 and the slope 20f of the intersection 20e of the tracking error signal waveform 16 and the minus side offset axis 20 are shown. , And an average slope value is obtained from the obtained slope 19f and slope 20f. The obtained average slope values of the slope 19f and the slope 20f are compared with a predetermined threshold value that is used for the subsequent processing to determine the process. In the present embodiment, the upper limit threshold is 1.1 times or more of the control target amplitude, and the lower limit threshold is 0.9 or less of the control target amplitude. These threshold values are compared with the average inclination values of the inclination 19d and the inclination 20d. If the inclination average values of the inclination 19f and the inclination 20f exceed the upper limit threshold or the lower limit threshold, the tracking error signal recording gain reduction means ( S10) and the tracking error signal recording gain increasing means (S11) to adjust the recording gain of the tracking error signal. The waveform B shown in FIG. 6 shows a case where there is no margin for the dynamic range of the digital signal processing unit 11 and the average value of the inclination 19f and the inclination 20f exceeds the upper limit threshold value. The tracking error signal is sent to the tracking error signal recording gain down means (S10), not limited to the value of the tracking error signal, but adjusted so that the gain is uniformly reduced by 1 to 5% and sent to the recording operation confirmation means (S1). The loop returning from the recording operation confirmation means (S1) to the recording operation confirmation means (S1) again through the tracking error signal gain averaging means (S9), the recording gain down means (S10), or the recording gain up means (S11) is repeated. As a result, the amplitude of the tracking error signal can be made constant.

  Note that the equivalent information of the tracking signal amplitude in the present embodiment is obtained by measuring the slope of the tracking error signal amplitude waveform at a portion where a certain amount of offset is performed in the amplitude direction from the reference voltage. The equivalent information of the signal amplitude may be anything as long as it has a correlation with the amplitude, and is limited to measuring the slope of the tracking error signal amplitude waveform in the portion where a certain amount of offset is performed in the amplitude direction from the reference voltage. is not. Further, the upper threshold and the lower threshold are not limited to 1.1 times or more and 0.9 times or less of the control target amplitude, and need to be changed depending on the characteristics of the tracking servo. Furthermore, the amount of gain adjustment of the tracking error signal is also different from the amplitude amount before the change, even if the upper limit threshold is exceeded or the lower limit threshold is exceeded. It is not limited to 1 to 5% uniformly and needs to be changed depending on the characteristics of the tracking servo.

  According to the present invention, the amplitude of the tracking error signal is compared, and the amplitude of the tracking error signal can be made constant by changing the amplitude based on the result. Prevents fluctuations in the amplitude of the tracking error signal due to variations in the characteristics of amplifiers and other electrical elements, temperature changes, and changes over time, and stabilizes the tracking servo during recording. The present invention can be applied to an optical disk device for recording / reproducing.

1 is a block diagram of a pickup control unit of an optical disc apparatus according to an embodiment of the present invention. The figure which shows the tracking error signal of the optical disk apparatus in one embodiment of this invention The figure which shows the correspondence of the offset and gain of the tracking error signal of the optical disk apparatus in one embodiment of the present invention 7 is a flowchart showing gain control of a tracking error signal in the optical disc apparatus according to the embodiment of the present invention. The figure which shows the gain control of the tracking error signal of the optical disk apparatus in one embodiment of this invention The figure which shows the gain control of the tracking error signal of the optical disk apparatus in one embodiment of this invention Block diagram of pickup control unit of optical disk apparatus Diagram showing the relationship between tracking offset and gain

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 2 Pickup module 3 Spindle motor 4 Optical pick-up 5 Carriage 6 Feed part 7 Feed motor 8 Analog signal process part 9 Servo process part 10 Motor drive part 11 Digital signal process part 12 Laser drive part 13 Controller 14 Light beam 15 Reference voltage axis 16 Tracking error signal waveform 17 Intersection 18 Inclination 19 Positive offset axis 19b, 19d, 19f Intersection 20 Negative offset axis 19a, 19c, 19e Intersection 20a, 20c, 20e Inclination 20b, 20d, 20f Inclination

Claims (6)

An optical disc apparatus including a control unit that performs tracking control of an optical pickup using a tracking error signal, wherein the control unit measures equivalent information of the tracking error signal amplitude, and obtains the obtained tracking error signal amplitude. The equivalent information is compared with a predetermined threshold value, and the tracking error signal amplitude amount is changed based on the comparison result. The tracking error signal amplitude equivalent information has a certain amount of offset in the amplitude direction from the reference voltage. An optical disc apparatus characterized by being obtained by measuring an inclination of a tracking error signal amplitude waveform of a performed portion . 2. The optical disc apparatus according to claim 1, wherein the tracking error signal amplitude amount is changed by changing the amplitude amount per time. The predetermined threshold, according to any one of claims 1, 2, characterized in that for controlling the recording gain of the tracking signal 1.1 times the value of the control target amplitude quantity as a threshold value of the upper limit Optical disk device. The predetermined threshold, according to any one of claims 1, 2, characterized in that for controlling the recording gain of the tracking signal 0.9 times the value of the control target amplitude of the lower threshold Optical disk device. The optical disc apparatus according to any one of claims 1 to 4, wherein an amplitude amount changed per time of the tracking error signal is 1 to 5% with respect to an amplitude amount before the change. A method of controlling an optical disk device that performs tracking control of an optical pickup using a tracking error signal, measuring equivalent information of the tracking error signal amplitude, and preliminarily determined as equivalent information of the obtained tracking error signal amplitude The tracking error signal amplitude amount is changed on the basis of the comparison result, and the tracking error signal amplitude equivalent information is a tracking error signal of a portion in which a fixed amount offset is performed in the amplitude direction from the reference voltage. A method for controlling an optical disc apparatus, which is obtained by measuring an inclination of an amplitude waveform .

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