JP2006172693A - Tilt adjusting circuit for optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tilt adjusting circuit for an optical disk drive which improves reading performance of optical disk data by setting an optical axis of a laser bean emitted from an optical pickup device roughly orthogonal to a signal surface of an optical disk. <P>SOLUTION: The tilt adjusting circuit for an optical disk drive 1 sets an optical axis LBa of a laser beam LB emitted from a light emitting element 11 of an optical pickup device 10 roughly orthogonal to the signal surface 520 of an optical disk 500, and the tilt adjusting circuit is provided with a jitter measuring circuit 40 capable of measuring flickering of a signal detected by a photodetector 15 of the optical pickup device 10, and a tracking tilt signal adjusting circuit 72 for adjusting angle shifting of an objective lens 13 based on jitters detected by the jitter measuring circuit 40 when the angle shifting occurs in the objective lens 13 of the optical pickup device 10 with respect to the signal surface 520 of the optical disk 500. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tilt adjustment circuit for an optical disc apparatus in which an optical pickup device of an optical disc apparatus for driving, for example, a CD (Compact Disc) series optical disc or a DVD (Digital Versatile Disc) series optical disc has a tilt function. is there.

  Conventional optical disc apparatuses having a tilt mechanism and a tilt function have been useful for correcting skew in a radial direction of a disc and correcting recording quality. The tilt in the optical pickup device means an angular deviation between the disc surface and the optical axis of the objective lens. The skew means “distortion” or “bend”.

As an apparatus having a conventional tilt function, for example, when performing tilt control, it is not necessary to add a power supply wire to the lens holder, and the optical head apparatus does not increase the size and weight of the lens holder. (For example, refer to Patent Document 1).
JP 2002-197698 A (pages 1, 2 and 1 to 3)

  However, in an optical disc apparatus provided with a conventional tilt mechanism, defocusing has been a problem. Focus means focus or focus. Also, defocusing means that the focal point of the laser beam emitted from the optical pickup device is shifted with respect to the pit portion of the disk being followed, and this makes the data recorded on the disk unreadable. means. A pit means a hole or a dent. “Focus loss” is sometimes abbreviated as “F drop” or the like.

  Defocusing occurs due to disk runout, disk eccentricity, disk vibration, and disk impact. When an optical disk device is used to reproduce data recorded on an optical disk, or when data is recorded on an optical disk, surface fluctuations of the disk and eccentricity of the disk occur constantly in the optical disk device. It is supposed to be. On the other hand, the vibration of the disk and the shock of the disk are suddenly generated.

  In a conventional optical disc apparatus in which tilt control is not performed, there is a concern that defocusing may occur due to disc surface deflection or disc eccentricity. Further, even if the focus is not lost, the optical axis of the optical pickup device is not orthogonal to the signal surface of the disk, and there is a problem that the data reading performance for the disk is deteriorated.

  The present invention is to solve the above-described problems. In view of the foregoing, the present invention provides a tilt adjustment circuit for an optical disc apparatus in which the optical axis emitted from the optical pickup device is substantially orthogonal to the signal surface of the optical disc and the data reading performance of the optical disc is improved. For the purpose.

In order to achieve the above object, a tilt adjusting circuit for an optical disc apparatus according to claim 1 of the present invention is such that the optical axis of laser light emitted from a light emitting element of an optical pickup device is substantially orthogonal to the signal surface of the optical disc. A tilt adjustment circuit for an optical disc apparatus, a jitter measurement circuit capable of measuring a fluctuation of a signal detected by a photodetector of the optical pickup device, and an objective of the optical pickup device with respect to the signal surface of the optical disc And a tracking tilt signal adjustment circuit that adjusts the angular deviation of the objective lens based on jitter detected by the jitter measurement circuit when an angular deviation is caused in the lens. .

  With the configuration described above, the optical axis of the laser light emitted from the light emitting element of the optical pickup device is likely to be substantially orthogonal to the signal surface of the optical disc. The tilt in the optical pickup device means an angular deviation between the signal surface of the optical disc and the optical axis of the laser light emitted from the light emitting element and transmitted through the objective lens. Jitter means a subtle fluctuation or distortion of a signal. The tilt adjustment circuit for an optical disc device is provided with a jitter measurement circuit capable of measuring the fluctuation of the signal detected by the photodetector of the optical pickup device. Therefore, the fluctuation of the signal is accurately detected by the jitter measurement circuit. Measured. The tilt adjustment circuit for the optical disc apparatus is based on the jitter detected by the jitter measurement circuit when an angle shift is caused in the objective lens of the optical pickup device with respect to the signal surface of the optical disc. Since a tracking tilt signal adjustment circuit for adjusting the angle deviation of the lens is provided, the optical axis of the laser beam emitted from the light emitting element of the optical pickup device is in a state substantially orthogonal to the signal surface of the optical disc. It is easy to be maintained. Accordingly, there is provided a tilt adjustment circuit for an optical disc apparatus that improves the data reading performance of the optical disc.

  The tilt adjustment circuit for an optical disc apparatus according to claim 2 outputs the signal detected by the photodetector as an RF signal to be a high frequency signal in the tilt adjustment circuit for optical disc apparatus according to claim 1. And an optical output signal processing circuit for detecting the jitter corresponding to the fluctuation of the RF signal when the RF signal is input to the jitter measuring circuit.

  With the above configuration, jitter is detected without the influence of noise on the reproduction signal of the optical disk. Noise (noise) means disturbance of electric signals or noise. The tilt adjustment circuit for the optical disc apparatus is provided with an optical output signal processing circuit that outputs a signal detected by the photodetector as an RF signal that is a high-frequency signal. An adverse effect on the reproduction signal of the optical disk is avoided. The RF signal means, for example, a signal converted to a high frequency that is substantially the same as a radio wave. “RF” is an abbreviation for “radio frequency”. Since the jitter has a frequency higher than the frequency range of the reproduction signal of the optical disc, the reproduction signal of the optical disc is processed in the optical disc apparatus as a signal not affected by the jitter.

  The tilt adjustment circuit for an optical disc apparatus according to claim 3 is the tilt adjustment circuit for an optical disc apparatus according to claim 1 or 2, wherein the objective lens is arranged in a direction substantially along the signal surface with respect to a recording portion of the optical disc. An optical output signal processing circuit is provided that generates a tracking error signal from the signal detected by the photodetector when a tracking error causing a positional deviation is about to occur.

  With the above configuration, it is easy to avoid the occurrence of a tracking error in the objective lens and an error in reading data from the optical disk. The tilt adjustment circuit for the optical disc apparatus includes an optical output signal processing circuit that generates a tracking error signal from the signal detected by the photodetector, and therefore the tracking error signal generated by the optical output signal processing circuit. Therefore, it is easy to avoid the occurrence of tracking errors in the objective lens of the optical pickup device.

  A tilt adjustment circuit for an optical disc apparatus according to claim 4 is a tracking servo circuit that enables execution of a tracking servo operation of the objective lens based on the tracking error signal in the tilt adjustment circuit for an optical disc apparatus according to claim 3. It is characterized by providing.

  With the above configuration, it is easy to avoid the occurrence of a tracking error in the objective lens and an error in reading data from the optical disk. The servo means a mechanism for automatically correcting and controlling the state of the object to be controlled and comparing it with a predetermined reference value. Since the tilt adjustment circuit for an optical disc apparatus includes a tracking servo circuit that enables the tracking servo operation of the objective lens to be executed based on the tracking error signal generated by the optical output signal processing circuit, the optical pickup apparatus When a tracking error is about to occur in the objective lens, a tracking servo operation is performed on the objective lens. Therefore, the occurrence of an error in reading data on the optical disk is easily prevented.

  The tilt adjustment circuit for an optical disc device according to claim 5 is the tilt adjustment circuit for optical disc device according to claim 4, wherein the tracking control signal output from the tracking servo circuit is input, and based on the tracking control signal, A tracking tilt bandpass filter circuit that extracts a signal corresponding to the rotation period of the optical disc is provided.

  With the above configuration, the optical axis of the laser light emitted from the light emitting element of the optical pickup device is easily maintained in a state substantially orthogonal to the signal surface of the optical disk. The optical disk apparatus tilt adjustment circuit includes a tracking tilt bandpass filter circuit that extracts a signal corresponding to the rotation period of the optical disk based on the tracking control signal output from the tracking servo circuit. Based on the signal corresponding to the rotation period, the optical axis of the laser beam emitted from the light emitting element of the optical pickup device is easily maintained substantially orthogonal to the signal surface of the optical disc.

  The tilt adjustment circuit for an optical disc device according to claim 6 is the tilt adjustment circuit for an optical disc device according to claim 5, wherein the tracking tilt signal adjustment circuit is a level of a signal extracted by the tracking tilt bandpass filter circuit. Is characterized by being adjustable.

  With the above configuration, the optical axis of the laser light emitted from the light emitting element of the optical pickup device is easily maintained in a state orthogonal to the signal surface of the optical disk. The optical disk apparatus tilt adjustment circuit includes a tracking tilt signal adjustment circuit capable of adjusting the level of the signal extracted by the tracking tilt bandpass filter circuit. The optical axes of the laser beams emitted from the light emitting elements are easily maintained in an orthogonal state with high accuracy.

  A tilt adjustment circuit for an optical disc device according to a seventh aspect of the present invention is the tilt adjustment circuit for an optical disc device according to the fifth or sixth aspect, further comprising a filter characteristic changing circuit capable of changing a filter characteristic of the tracking tilt bandpass filter circuit. It is characterized by.

With the above configuration, the tracking tilt adjustment of the objective lens with respect to the optical disc is easily performed satisfactorily. As an optical disk, an optical disk that is rotated in a state where the linear velocity is substantially constant when the optical disk is rotated is generally used. When such optical disk data is read, the disk rotation speed at the time of reading data from the optical pickup device at the inner periphery of the optical disk and the disk rotation speed at the time of reading data from the optical pickup device at the outer periphery of the optical disk are: Different. Equipped with a filter characteristic change circuit that can change the filter characteristics of the tracking tilt bandpass filter circuit, so that even if the rotation speed of the optical disk changes, a signal is sent from the filter characteristic change circuit to the tracking tilt bandpass filter circuit. Thus, the characteristics of the tracking tilt bandpass filter circuit are changed to the optimum state. Therefore, stable tracking tilt adjustment is performed even if the rotational speed of the optical disk changes.

  The tilt adjustment circuit for an optical disc apparatus according to claim 8 is the tilt adjustment circuit for optical disc apparatus according to any one of claims 1 to 7, wherein the optical disc is an eccentric disc, and the signal surface of the eccentric disc is arranged on the signal surface. On the other hand, when the objective lens of the optical pickup device is swung substantially along the tracking direction and the angular deviation of the objective lens of the optical pickup device is about to occur with respect to the signal surface of the eccentric disk. In addition, the tracking tilt signal adjustment circuit generates a signal capable of correcting the angular deviation of the objective lens based on the jitter.

  With the configuration described above, even when the optical disk is an eccentric disk, the optical axis of the laser light emitted from the light emitting element of the optical pickup device is likely to be orthogonal to the signal surface of the optical disk. The tilt adjustment circuit for the optical disc apparatus is provided with a tracking tilt signal adjustment circuit that generates a signal capable of correcting the angular deviation of the objective lens based on the jitter detected by the jitter measurement circuit. It is easy to avoid the occurrence of an angular deviation of the objective lens of the optical pickup device with respect to the signal surface. Therefore, it is easy to prevent an optical disk data reading error from occurring when the optical pickup device is used and the optical disk data is being read.

  The tilt adjustment circuit for an optical disc device according to claim 9 is the tilt adjustment circuit for an optical disc device according to any one of claims 1 to 8, based on the jitter detected by the jitter measurement circuit. A control unit is provided that generates a control adjustment signal used when the angular deviation of the objective lens is adjusted, and transmits the control adjustment signal to the tracking tilt signal adjustment circuit.

  With the configuration described above, the optical axis of the laser light emitted from the light emitting element of the optical pickup device is likely to be substantially orthogonal to the signal surface of the optical disc. In the control unit constituting the tilt adjustment circuit for the optical disc apparatus, a control adjustment signal used when the angular deviation of the objective lens is adjusted is generated based on the jitter detected by the jitter measurement circuit. The control adjustment signal generated by the control unit is transmitted to the tracking tilt signal adjustment circuit, and the tracking tilt signal adjustment circuit adjusts the signal for adjusting the angular deviation of the objective lens.

  The tilt adjustment circuit for an optical disc device according to claim 10 is the tilt adjustment circuit for an optical disc device according to any one of claims 1 to 9, wherein the optical pickup device has the tilt adjustment circuit with respect to the signal surface of the optical disc. An offset adjustment circuit is provided that outputs an offset signal for correcting the angular deviation when the angular deviation is about to occur in the objective lens.

  With the above configuration, the optical axis of the laser beam emitted from the light emitting element of the optical pickup device is easily set to be orthogonal to the signal surface of the optical disc. The tilt adjustment circuit for the optical disc apparatus outputs an offset signal for correcting the angular deviation of the objective lens when the angular deviation of the objective lens of the optical pickup device is about to occur with respect to the signal surface of the optical disc. Since the adjustment circuit is provided, the angular deviation of the objective lens of the optical pickup device with respect to the signal surface of the optical disk is accurately corrected.

  An optical disc apparatus tilt adjustment circuit according to claim 11 is the optical disc apparatus tilt adjustment circuit according to claim 10, wherein an offset output control signal for outputting the offset signal from the offset adjustment circuit based on the jitter is a control unit. And the offset output control signal is transmitted from the control unit to the offset adjustment circuit.

  With the above configuration, the tracking tilt adjustment of the optical pickup device is easily performed accurately. By transmitting an offset output control signal from the control unit to the offset adjustment circuit, the offset signal is output from the offset adjustment circuit.

  The tilt adjustment circuit for an optical disc apparatus according to claim 12 is the tilt adjustment circuit for an optical disc apparatus according to claim 10 or 11, wherein the offset adjustment circuit includes the tracking tilt adjustment signal output from the tracking tilt signal adjustment circuit. And an addition circuit for adding the offset signal output from the signal.

  With the above configuration, the optical axis of the laser beam emitted from the light emitting element of the optical pickup device is easily maintained in a state of being accurately orthogonal to the signal surface of the optical disc. The optical disc apparatus tilt adjustment circuit includes an addition circuit for adding the offset signal output from the offset adjustment circuit to the tracking tilt adjustment signal output from the tracking tilt signal adjustment circuit. Thus, a signal in which the tracking tilt adjustment signal and the offset signal are combined is generated. By this signal, the angle adjustment of the objective lens of the optical pickup device with respect to the signal surface of the optical disc is performed with high accuracy.

  A tilt adjustment circuit for an optical disc apparatus according to a thirteenth aspect is the tilt adjustment circuit for an optical disc apparatus according to the twelfth aspect, further comprising a tilt coil drive circuit to which the addition signal output from the addition circuit is input, In order to adjust the angle of the objective lens of the apparatus, a drive signal to be sent to a tilt adjustment coil of the optical pickup device is generated by the tilt coil drive circuit based on the addition signal. To do.

  With the above configuration, the angle adjustment of the objective lens of the optical pickup device with respect to the signal surface of the optical disc is performed reliably. Based on the addition signal output from the addition circuit, a drive signal to be sent to the tilt adjustment coil of the optical pickup device is generated by the tilt coil drive circuit. When an angle shift is about to occur in the lens, the angle shift of the objective lens is corrected by a drive signal sent to the tilt adjustment coil of the optical pickup device.

  As described above, according to the first aspect of the present invention, the optical axis of the laser beam emitted from the light emitting element of the optical pickup device can be easily made perpendicular to the signal surface of the optical disc. The tilt adjustment circuit for an optical disc device is provided with a jitter measurement circuit capable of measuring the fluctuation of the signal detected by the photodetector of the optical pickup device. Therefore, the fluctuation of the signal is accurately detected by the jitter measurement circuit. Measured. The tilt adjustment circuit for the optical disc apparatus is based on the jitter detected by the jitter measurement circuit when an angle shift is caused in the objective lens of the optical pickup device with respect to the signal surface of the optical disc. Since it is equipped with a tracking tilt signal adjustment circuit that adjusts the angle deviation of the lens, the optical axis of the laser beam emitted from the light emitting element of the optical pickup device is kept orthogonal to the signal surface of the optical disc. It becomes easy to be done. Accordingly, it is possible to provide a tilt adjustment circuit for an optical disc apparatus with improved data reading performance of the optical disc.

According to the second aspect of the present invention, it is possible to detect jitter without the influence of noise on the reproduction signal of the optical disk. The tilt adjustment circuit for the optical disc apparatus is provided with an optical output signal processing circuit that outputs a signal detected by the photodetector as an RF signal that is a high-frequency signal. It is possible to avoid adversely affecting the reproduction signal of the optical disk. Since the jitter has a frequency higher than the frequency range of the reproduction signal of the optical disc, the reproduction signal of the optical disc is processed in the optical disc apparatus as a signal not affected by the jitter.

  According to the third aspect of the present invention, it is possible to avoid occurrence of a tracking error in the objective lens and an error in reading data on the optical disk. The tilt adjustment circuit for the optical disc apparatus includes an optical output signal processing circuit that generates a tracking error signal from the signal detected by the photodetector, and therefore the tracking error signal generated by the optical output signal processing circuit. This avoids the occurrence of tracking errors in the objective lens of the optical pickup device.

  According to the fourth aspect of the present invention, it is avoided that a tracking error occurs in the objective lens and a reading error of data on the optical disc occurs. Since the tilt adjustment circuit for an optical disc apparatus includes a tracking servo circuit that enables the tracking servo operation of the objective lens to be executed based on the tracking error signal generated by the optical output signal processing circuit, the optical pickup apparatus When a tracking error is about to occur in the objective lens, a tracking servo operation is performed on the objective lens. Therefore, the occurrence of an error in reading data on the optical disk is prevented.

  According to the invention described in claim 5, the optical axis of the laser beam emitted from the light emitting element of the optical pickup device is maintained in a state orthogonal to the signal surface of the optical disc. The optical disk apparatus tilt adjustment circuit includes a tracking tilt bandpass filter circuit that extracts a signal corresponding to the rotation period of the optical disk based on the tracking control signal output from the tracking servo circuit. The optical axis of the laser beam emitted from the light emitting element of the optical pickup device is maintained in an orthogonal state with respect to the signal surface of the optical disc based on the signal corresponding to the rotation period of.

  According to the invention described in claim 6, the optical axis of the laser beam emitted from the light emitting element of the optical pickup device is maintained in a state orthogonal to the signal surface of the optical disc. The optical disk apparatus tilt adjustment circuit includes a tracking tilt signal adjustment circuit capable of adjusting the level of the signal extracted by the tracking tilt bandpass filter circuit. The optical axes of the laser beams emitted from the light emitting elements are accurately maintained at a right angle.

  According to the seventh aspect of the invention, the tracking tilt adjustment of the objective lens with respect to the optical disc is performed satisfactorily. As an optical disk, an optical disk that is rotated in a state where the linear velocity is substantially constant when the optical disk is rotated is generally used. When such optical disk data is read, the disk rotation speed at the time of reading data from the optical pickup device at the inner periphery of the optical disk and the disk rotation speed at the time of reading data from the optical pickup device at the outer periphery of the optical disk are: Different. Equipped with a filter characteristic change circuit that can change the filter characteristics of the tracking tilt bandpass filter circuit, so that even if the rotation speed of the optical disk changes, a signal is sent from the filter characteristic change circuit to the tracking tilt bandpass filter circuit. Thus, the characteristics of the tracking tilt bandpass filter circuit are changed to the optimum state. Therefore, stable tracking tilt adjustment is performed even if the rotational speed of the optical disk changes.

According to the eighth aspect of the present invention, even when the optical disk is an eccentric disk, the optical axis of the laser beam emitted from the light emitting element of the optical pickup device is orthogonal to the signal surface of the optical disk. The The tilt adjustment circuit for the optical disc apparatus is provided with a tracking tilt signal adjustment circuit that generates a signal capable of correcting the angular deviation of the objective lens based on the jitter detected by the jitter measurement circuit. It is avoided that an angle shift of the objective lens of the optical pickup device occurs with respect to the signal surface. Therefore, it is possible to prevent an optical disk data reading error from occurring when the optical pickup device is used to read the optical disk data.

  According to the ninth aspect of the present invention, the optical axis of the laser light emitted from the light emitting element of the optical pickup device is substantially orthogonal to the signal surface of the optical disc. In the control unit constituting the tilt adjustment circuit for the optical disc apparatus, a control adjustment signal used when the angular deviation of the objective lens is adjusted is generated based on the jitter detected by the jitter measurement circuit. The control adjustment signal generated by the control unit is transmitted to the tracking tilt signal adjustment circuit, and the tracking tilt signal adjustment circuit adjusts the signal for adjusting the angular deviation of the objective lens.

  According to the tenth aspect of the present invention, the optical axis of the laser beam emitted from the light emitting element of the optical pickup device is orthogonal to the signal surface of the optical disc. The tilt adjustment circuit for the optical disc apparatus outputs an offset signal for correcting the angular deviation of the objective lens when the angular deviation of the objective lens of the optical pickup device is about to occur with respect to the signal surface of the optical disc. Since the adjustment circuit is provided, the angular deviation of the objective lens of the optical pickup device with respect to the signal surface of the optical disk can be accurately corrected.

  According to the invention described in claim 11, the tracking tilt adjustment of the optical pickup device is performed accurately. By transmitting an offset output control signal from the control unit to the offset adjustment circuit, the offset signal is output from the offset adjustment circuit.

  According to the twelfth aspect of the invention, the optical axis of the laser light emitted from the light emitting element of the optical pickup device is accurately maintained perpendicular to the signal surface of the optical disc. The optical disc apparatus tilt adjustment circuit includes an addition circuit for adding the offset signal output from the offset adjustment circuit to the tracking tilt adjustment signal output from the tracking tilt signal adjustment circuit. Thus, a signal in which the tracking tilt adjustment signal and the offset signal are combined is generated. With this signal, the angle adjustment of the objective lens of the optical pickup device with respect to the signal surface of the optical disk can be accurately performed.

  According to the thirteenth aspect of the present invention, the angle adjustment of the objective lens of the optical pickup device with respect to the signal surface of the optical disc can be reliably performed. Based on the addition signal output from the addition circuit, a drive signal to be sent to the tilt adjustment coil of the optical pickup device is generated by the tilt coil drive circuit. When an angle shift is about to occur in the lens, the angle shift of the objective lens is corrected by a drive signal sent to the tilt adjustment coil of the optical pickup device.

  An embodiment of a tilt adjustment circuit for an optical disc apparatus according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a system configuration diagram showing an embodiment of a tilt adjustment circuit for an optical disc apparatus according to the present invention, FIG. 2 is an explanatory diagram showing an operating state of a surface runout disc, and FIG. FIG. 4 shows an operating state of the eccentric disk, and FIG. 4A is an explanatory diagram showing a state in which the objective lens is tilted toward the disk outer peripheral side of the eccentric disk. b) is an explanatory diagram showing a state in which the objective lens is tilted toward the inner circumferential side of the eccentric disc, FIG. 5 is a waveform diagram showing a swing period when the eccentric disc is rotated, and FIG. FIG. 7 is a flowchart showing a process when the tracking tilt adjustment is performed. FIG. 7 is a flowchart showing a process when the tracking tilt adjustment is performed.

  As described above, the tilt in the optical pickup device 10 (FIG. 1) is the angle between the signal surface 520 of the optical disc 500 and the optical axis LBa of the laser beam LB emitted from the light emitting element 11 and transmitted through the objective lens 13. It means a gap. Data such as information recorded on the optical disc 500 is reproduced using the optical disc apparatus 1. The optical disk device 1 is used to record data such as information on the optical disk 500. As an optical disk, for example, a read-only optical disk such as “CD-ROM” and “DVD-ROM”, a write-once optical disk such as “CD-R”, “DVD-R”, and “DVD + R”, and “CD- RW ”,“ DVD-RW ”,“ DVD + RW ”(registered trademark),“ DVD-RAM ”,“ HD DVD ”(registered trademark),“ Blu-ray Disc ”(trademark), etc. can be written / erased and rewritten Type optical disk.

  “CD” is an abbreviation for “Compact Disc” (trademark). “DVD” is an abbreviation for “Digital Versatile Disc” (registered trademark). Further, “ROM” in “CD-ROM” or “DVD-ROM” is an abbreviation for “Read Only Memory”. The CD-ROM or DVD-ROM is dedicated for data reading. In addition, “R” in “CD-R”, “DVD-R” or “DVD + R” is an abbreviation for “Recordable”. CD-R, DVD-R, or DVD + R can be written with data. “RW” in “CD-RW”, “DVD-RW” or “DVD + RW” is an abbreviation for “ReWritable”. CD-RW, DVD-RW, or DVD + RW is data rewritable. “DVD-RAM” is an abbreviation for “Digital Versatile Disc Random Access Memory”. The DVD-RAM can read / write / erase data.

  “HD DVD” is an abbreviation for “High Definition DVD”. The “HD DVD” is compatible with the conventional DVD series and has a larger storage capacity than the conventional DVD series disks. In the conventional CD, an infrared laser is used. In addition, a red laser is used for a conventional DVD. However, when data / information recorded on the optical disk 500 of “HD DVD” is read, a blue-violet laser is used. “Blu-ray” means a blue-violet laser employed to realize high-density recording, compared to a red laser that has been used for conventional signal reading and writing.

  Further, examples of the optical disc include an optical disc (not shown) in which signal surfaces are provided on both sides of the disc and data writing / erasing and data rewriting are possible. Further, examples of the optical disc include an optical disc (not shown) provided with a two-layer signal surface and capable of data writing / erasing and data rewriting. Also, for example, an “HD-DVD” optical disk (not shown) provided with a three-layer signal surface and capable of data writing / erasing and data rewriting is also included. In addition, for example, a “Blu-ray Disc” optical disc (not shown) provided with a four-layer signal surface and capable of data writing / erasing and data rewriting is also included.

A recording unit 510 for storing each data on the optical disc 500 is provided on the signal surface 520 of the optical disc 500. The signal surface of the optical disc is handled as a substantially planar signal layer surface, a substantially planar recording layer surface, or the like. The recording unit 510 of the optical disc 500 is formed as many fine pits 510. As described above, a pit means a hole or a dent. When the disk-shaped optical disk 500 is viewed in plan, many fine pits 510 are arranged in a spiral shape. When the optical disc 500 is viewed from the signal surface 520 side of the optical disc 500, the pits 510 are spiral. Since each pit 510 is very small, each pit 510 is not visible. In FIG. 1, FIG. 2, and FIG. 4, the signal layer 520 and the pits 510 of the optical disc 500 are shown using broken lines for convenience. Instead of the pit 510, an optical disk (500) provided with a groove (not shown) capable of recording each signal can be used as the recording unit (510) of the optical disk (500). A groove means an elongated dent.

  The optical disk 500 is rotated by a spindle motor 250 constituting the optical disk apparatus 1 (FIG. 1). The spindle motor 250 is rotationally driven by a spindle motor drive circuit 230. Due to the synchronization signal recorded on the optical disc 500, the optical disc 500 is rotated with a constant linear velocity. Such a method is called a CLV method. “CLV” is an abbreviation for “constant linear velocity”.

  Further, for example, a pulse signal generated in accordance with the rotation of the spindle motor 250 is used so that the rotation drive control of the spindle motor 250 is performed by a constant angular velocity method. Such a method is called a CAV method. “CAV” is an abbreviation for “constant angular velocity”. The drive circuit is called a driver or the like.

  The tilt adjustment circuit of the optical disc apparatus 1 shown in FIG. 1 uses the optical axis LBa of the laser beam LB emitted from the laser diode 11 of the optical pickup device 10 and focused by the objective lens 13 of the optical pickup device 10 as a signal of the optical disc 500. It is intended to always be substantially orthogonal to the layer 520 (FIGS. 1, 2, and 4). The signal layer 520 of the optical disc 500 is formed as a substantially planar disk layer.

  The optical pickup is generally abbreviated as “OPU”. In addition, “optical pickup unit” is sometimes abbreviated as “OPU”. Here, for convenience, the optical pickup device is abbreviated as OPU. The objective lens is abbreviated as “OBL”. The laser diode is abbreviated as LD. A laser diode 11 was used as the light emitting element 11 (FIG. 1). A PDIC 15 was used as the photodetector 15. “PDIC” is an abbreviation for “Photo Diode IC”. The PDIC 15 receives the laser beam reflected from the disk 500, converts the signal into an electric signal, and detects information recorded on the disk 500. The PDIC 15 receives the laser beam reflected from the disk 500, converts the signal into an electrical signal, and operates a servo mechanism (not shown) of a lens holder with an OBL 13 (not shown) constituting the optical pickup device 10. It is intended for operation.

  When data / information is read / written from / to the optical disc 500, the OPU 10 of the optical disc apparatus 1 moves substantially along the inner / outer direction Db of the rotating optical disc 500. When focus adjustment of the OBL 13 of the OPU 10 is performed on the rotating optical disk 500, the OBL 13 is usually finely moved along the vertical direction Da of the disk to adjust the position of the OBL 13. As described above, the focus means focus or focus. Further, the disk vertical direction Da means a direction perpendicular to the disk surface 505 formed from the inner periphery 501 to the outer periphery 502 of the optical disk 500, for example, when the optical disk 500 is maintained in a substantially horizontal state. The disc surface 505 of the optical disc 500 is formed substantially parallel to the signal surface 520 of the optical disc 500.

The state when the focus adjustment of the OBL 13 with respect to the optical disc 500 is performed will be described in detail. The OBL 13 is moved slightly along the upper direction Da ₂ or the lower direction Da ₁ of the optical disc 500 (FIG. 2). Spot alignment of the laser beam that has passed through the OBL 13 is performed on the recording unit 510.

  In addition, when the tracking adjustment of the OBL 13 of the OPU 10 is performed on the rotating optical disk 500 (FIG. 1), the OBL 13 is usually finely moved along the inside / outside direction Db of the disk to adjust the position of the OBL 13. Tracking is the tracking of a microscopic pit (hole, dent), groove (groove), wobble (meander), etc. provided on a disk using light, and the trajectory drawn in a spiral shape. It means to set the position. Also, the disc inner / outer direction Db means a direction along the disc surface 505 between the inner peripheral portion 501 and the outer peripheral portion 502 of the optical disc 500 when the optical disc 500 is maintained in a substantially horizontal state, for example.

The state when the tracking adjustment of the OBL 13 with respect to the optical disc 500 is performed will be described in detail. The OBL 13 is moved slightly along the outer direction Db ₂ or the inner direction Db ₁ of the optical disc 500 (FIG. 4), and the recording of the optical disc 500 is performed. The spot alignment of the laser beam that has passed through the OBL 13 is performed on the unit 510.

  Definitions relating to directions such as “upper”, “lower”, “inner”, “outer” and the like in this specification are definitions for convenience for describing the optical disc apparatus 1, the optical pickup device 10, and the optical disc 500.

  This tilt adjustment circuit for an optical disc apparatus includes a jitter measurement circuit 40 that can measure the fluctuation of a signal detected by the PDIC 15 of the OPU 10. In addition, the tilt adjustment circuit for the optical disc apparatus is based on the jitter detected by the jitter measurement circuit 40 when an angle shift is caused in the OBL 13 of the OPU 10 with respect to the signal layer 520 of the optical disc 500. Tilt signal adjustment circuits 71 and 72 for adjusting the tilt of the angle deviation are provided. The tilt signal adjustment circuits 71 and 72 include a focus tilt signal adjustment circuit 71 for performing focus tilt adjustment of the OBL 13 and a tracking tilt signal adjustment circuit 72 for performing tracking tilt adjustment of the OBL 13. For example, amplifiers are used as the tilt signal adjustment circuits 71 and 72. Amplifier is an abbreviation for amplifier and means an amplifier.

  Jitter means a subtle fluctuation or distortion of a signal. Reducing jitter is a basic indicator of reproduction performance on CDs and DVDs. The jitter amount is determined by the standard.

  If the tilt adjusting circuit is configured in the optical disc apparatus 1, the optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 is always easily made substantially orthogonal to the signal layer 520 of the optical disc 500. . Since the optical disk apparatus tilt adjustment circuit includes the jitter measurement circuit 40 that can measure the fluctuation of the signal detected by the PDIC 15 of the OPU 10, the fluctuation of the signal is accurately measured by the jitter measurement circuit 40. The Further, the tilt adjustment circuit for the optical disc apparatus is based on the jitter detected by the jitter measurement circuit 40 when an angle shift is caused in the OBL 13 of the OPU 10 with respect to the signal layer 520 of the optical disc 500. Therefore, the optical axis LBa of the laser light LB emitted from the LD 11 of the OPU 10 is the signal layer of the optical disc 500. It becomes easy to always maintain the state substantially orthogonal to 520. Therefore, a tilt adjustment circuit for an optical disc apparatus with improved data reading performance of the optical disc 500 is provided to an assembly manufacturer of the optical disc apparatus 1, a user of the optical disc apparatus 1, and the like.

The tilt adjustment circuit for the optical disc apparatus includes a system control microcomputer 80 to which a jitter signal detected by the jitter measurement circuit 40 is input. The jitter signal input to the system control microcomputer 80 is input to the tilt signal adjustment circuits 71 and 72 while being controlled by the microcomputer 80. A micro computer means a micro computer. The microcomputer is abbreviated as a microcomputer or the like.

  The system control microcomputer 80 is a CPU, a system controller, a microprocessor, a microcomputer, or the like, and is a control unit 80 that controls system control of the optical disc apparatus 1 in general. “CPU” is an abbreviation for “central processing unit” and means a central processing unit. Each function of the system control microcomputer 80 is realized by software so-called programs. Each function implemented by software is stored in a memory (not shown) accessible by the system control microcomputer 80.

  Further, the tilt adjustment circuit for the optical disk device outputs a signal detected by the PDIC 15 as an RF signal that is a high frequency signal, and optical output signal processing that causes the data recorded on the optical disk 500 to be a data reproduction signal A circuit 30 is provided. The RF signal means, for example, a signal converted to a high frequency that is substantially the same as a radio wave. “RF” is an abbreviation for “radio frequency”. When an RF signal is input to the jitter measuring circuit 40, jitter is detected corresponding to the fluctuation of the RF signal.

  By providing the optical output signal processing circuit 30 in the circuit, jitter is detected without the influence of noise on the reproduction signal of the optical disc 500 or the like. Noise (noise) means disturbance of electric signals or noise. The optical disc drive tilt adjustment circuit outputs a signal detected by the PDIC 15 as an RF signal that is a high-frequency signal, and an optical output signal processing circuit 30 that makes data recorded on the optical disc 500 a data reproduction signal. Therefore, it is avoided that the detected jitter adversely affects the reproduction signal of the optical disc 500. Since the jitter has a frequency higher than the frequency range of the reproduction signal of the optical disc 500, the reproduction signal of the optical disc 500 is processed in the optical disc apparatus 1 as a signal not affected by the jitter.

  The optical output signal processing circuit 30 includes a focus error signal when the OBL 13 of the OPU 10 is shifted along the focus direction Df with respect to the optical disc 500, and the OBL 13 of the OPU 10 is shifted along the tracking direction Dt with respect to the optical disc 500. The front-end processing unit 30 can generate a tracking error signal and a signal that makes it possible to reproduce data recorded on the optical disc 500. The focus error means that the focus of the OBL 13 is displaced in the direction substantially orthogonal to the signal layer 520 with respect to the pit 510 or the groove of the optical disc 500. The tracking error means that the focus of the OBL 13 is displaced in the direction substantially along the signal layer 520 with respect to the pit 510 or groove of the optical disc 500.

  When the synchronous system is detected from the RF signal, the time variation of the frequency F is detected by the reference clock. The smaller the time variation, the smaller the time variation and the better the performance. The reference clock is abbreviated as reference CLK. The synchronous system will be described, for example, 3T to 11T for CDs and 3T to 14T for DVDs.

  The tilt adjustment circuit for the optical disc apparatus includes a front-end processing unit 30 that generates a focus error signal from a signal detected by the PDIC 15 when a focus error is about to occur in the OBL 13 of the OPU 10. .

  If the front end processing unit 30 is provided in the tilt adjustment circuit, it is easy to avoid the occurrence of a focus error in the OBL 13 and a data reading error in the optical disc 500. Since the optical disk apparatus tilt adjustment circuit includes the front end processing unit 30 that generates a focus error signal from the signal detected by the PDIC 15, the focus error signal generated by the front end processing unit 30 A focus error occurring in the OBL 13 of the OPU 10 is easily avoided.

  In addition, the tilt adjustment circuit for the optical disk apparatus includes a focus servo circuit 41 that enables a focus servo operation of a lens holder (not shown) including the OBL 13 to be executed based on the focus error signal. As described above, the servo means a mechanism for automatically correcting and controlling the state of the object to be controlled and comparing it with a predetermined reference value.

  If the focus servo circuit 41 is provided in the tilt adjustment circuit, it is easy to avoid the occurrence of a focus error in the OBL 13 and an error in reading data on the optical disc 500. The optical disk apparatus tilt adjustment circuit includes a focus servo circuit 41 that enables the focus servo operation of the lens holder including the OBL 13 to be executed based on the focus error signal generated by the front end processing unit 30. When a focus error is about to occur in the OBL 13 of the optical pickup device, a focus servo operation is performed on the OBL 13. Therefore, the occurrence of an error in reading data on the optical disc 500 is easily prevented.

  The focus servo circuit 41 is configured using an equalizer. An equalizer is an electric circuit for processing and adjusting the overall frequency characteristics of a signal such as an audio signal. The equalizer is abbreviated as “EQ”.

  The tilt adjustment circuit for the optical disk apparatus includes a focus coil drive circuit 51 to which a focus control signal output from the focus servo circuit 41 is input. When the focus of the laser beam LB focused by the OBL 13 is shifted along the focus direction Df of the OBL 13 with respect to the pit 510 of the optical disc 500, the focus coil drive is performed to adjust the focus of the OBL 13 of the OPU 10 A focus drive signal is sent from the circuit 51 to the focus coil 21 of the OPU 10. As a result, the occurrence of a focus error in the optical pickup device 10 is easily avoided.

  Further, the tilt adjustment circuit for the optical disc apparatus receives the focus control signal FDO output from the focus servo circuit 41, and extracts a signal corresponding to the rotation cycle Cf (FIG. 3) of the optical disc 500 based on the focus control signal FDO. A focus tilt bandpass filter circuit 61 (FIG. 1) is provided.

  FDO in this specification is an abbreviation for “focus drive out”. The band-pass filter is abbreviated as “BPF”. BPF means a filter that passes only a predetermined range of frequency signals and attenuates signals other than the predetermined range of frequency signals.

If the focus tilt bandpass filter circuit 61 is provided in the tilt adjustment circuit, the optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 is always substantially orthogonal to the signal layer 520 of the optical disc 500. To be easily maintained. The optical disk apparatus tilt adjustment circuit includes a focus tilt bandpass filter circuit 61 that extracts a signal corresponding to the rotation period Cf of the optical disk 500 based on the focus control signal FDO output from the focus servo circuit 41. Therefore, based on a signal corresponding to the rotation period Cf of the optical disc 500, the optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 is always maintained substantially orthogonal to the signal layer 520 of the optical disc 500. It becomes easy.

  The spindle motor drive circuit 230 rotates the spindle motor 250 and, for example, the spindle motor drive circuit 230 detects a rotation period signal of the optical disc 500. At this time, this signal is input to the focus tilt bandpass filter circuit 61 via the filter characteristic changing circuit 210 that can change the filter characteristic of the focus tilt bandpass filter circuit 61.

  The tilt signal adjustment circuits 71 and 72 include a focus tilt signal adjustment circuit 71 that can adjust the level of the signal extracted by the focus tilt bandpass filter circuit 61.

  If the focus tilt signal adjustment circuit 71 is provided in the tilt adjustment circuit, the optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 is always kept orthogonal to the signal layer 520 of the optical disc 500. It becomes easy to be done. The optical disc apparatus tilt adjustment circuit includes a focus tilt signal adjustment circuit 71 that can adjust the level of the signal extracted by the focus tilt bandpass filter circuit 61. The optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 is easily maintained in a state of being orthogonal to each other with high accuracy.

  This tilt adjustment circuit for an optical disc apparatus includes a filter characteristic changing circuit 210 that can change the filter characteristics of the bandpass filter circuits 61 and 62.

  More specifically, the tilt adjustment circuit for the optical disc apparatus includes a filter characteristic changing circuit 210 that can change the filter characteristic of the focus tilt bandpass filter circuit 61.

  If the filter characteristic changing circuit 210 capable of changing the filter characteristic of the focus tilt bandpass filter circuit 61 is provided in the tilt adjusting circuit for the optical disc apparatus, the focus tilt adjustment of the OBL 13 with respect to the optical disc 500 is easily performed satisfactorily. Become. As the optical disk 500, an optical disk 500 that is rotated in a state where the linear velocity is substantially constant when the optical disk 500 is rotated, that is, a so-called CLV optical disk 500 is generally used. When such information / data reading / writing of the optical disc 500 is performed, the number of revolutions of the OPU 10 in the vicinity of the inner peripheral portion 501 of the optical disc 500 at the time of reading / writing information / data of the OPU 10 Disc rotation speed is different when reading / writing information / data.

  Since the filter characteristic changing circuit 210 capable of changing the filter characteristic of the focus tilt bandpass filter circuit 61 is provided, the focus tilt bandpass filter circuit 61 is changed from the filter characteristic changing circuit 210 even if the rotational speed of the optical disc 500 is changed. Is sent, and the characteristics of the focus tilt bandpass filter circuit 61 are changed to the optimum state. Therefore, stable focus tilt adjustment is performed even if the rotational speed of the optical disk 500 changes.

In the optical disc apparatus 1, for example, the normal rotation speed of the optical disc 500 when a music appreciation CD is reproduced is approximately 200 to 500 rpm. rpm (revolutions per minute) means the number of revolutions per minute, that is, the number of revolutions per minute. For example, since the CD is an optical disk of a constant linear velocity method, the normal rotation speed of the optical disk 500 when the music appreciation CD data is reproduced near the inner periphery 501 of the optical disk 500 is about 500 rpm. is there. On the other hand, the normal rotation speed of the optical disc 500 when the music appreciation CD data is reproduced near the outer periphery 502 of the optical disc 500 is about 200 rpm.

  The normal rotation speed of the optical disc 500 when the music appreciation CD data is reproduced between the vicinity of the inner periphery 501 of the optical disc 500 and the vicinity of the outer periphery 502 of the optical disc 500 is controlled in the optical disc apparatus 1. By being performed, for example, 500 rpm, 400 rpm, 300 rpm, and 200 rpm are varied.

  The optical disk device 1 has a disk rotation speed of, for example, 1 × speed, 2 × speed, 4 × speed, 8 × speed, 12 × speed, 16 × speed, 24 × speed, 32 × speed, 48 × speed, and 64 × speed with respect to a normal disk speed. Data / information on the optical disc 500 can be read. Further, the optical disc apparatus 1 has, for example, 1 × speed, 2 × speed, 4 × speed, 8 × speed, 12 × speed, 16 × speed, 24 × speed, 32 × speed, 48 × speed, and 64 × speed with respect to the normal disk speed. Thus, data / information can be recorded on the optical disc 500. These speeds vary depending on the type of the optical disk 500 and the like. Further, the rotation method of the optical disc 500 when data / information is recorded on the optical disc 500 is performed based on the constant linear velocity method (CLV method), the constant angular velocity method (CAV method), or the like.

  The jitter signal output from the system control microcomputer 80 is input to the focus tilt signal adjustment circuit 71.

  Further, the optical disc 500 is, for example, a surface shake disc 500F (FIG. 2), and the OBL 13 of the OPU 10 is swung substantially along the focus direction Df with respect to the signal layer 520 of the surface shake disc 500F. When an angle shift is generated in the OBL 13 of the OPU 10 with respect to 520, the tilt signal adjustment circuits 71 and 72 (FIG. 1) generate a signal capable of correcting the angle shift of the OBL 13 based on the jitter. A focus tilt signal adjustment circuit 71 is provided.

  The OBL 13 of the OPU 10 is swung substantially along the focus direction Df with respect to the signal layer 520 of the surface shake disc 500F (FIG. 2), and an angle shift may occur in the OBL 13 of the OPU 10 with respect to the signal layer 520 of the surface shake disc 500F. Then, the focus tilt signal adjustment circuit 71 (FIG. 1) generates a signal that can correct the angular deviation of the OBL 13 based on the jitter.

  If such a tilt adjustment circuit for an optical disc apparatus is configured, even if the optical disc 500 provided in the optical disc apparatus 1 is a surface wobbling disc 500F, the signal is emitted from the LD 11 of the OPU 10 to the signal layer 520 of the optical disc 500F. The optical axis LBa of the laser beam LB thus made is always easy to be orthogonal. The optical disc apparatus tilt adjustment circuit includes a focus tilt signal adjustment circuit 71 that generates a signal capable of correcting the angular deviation of the OBL 13 based on the jitter detected by the jitter measurement circuit 40. It is easy to avoid the occurrence of the angular deviation of the OBL 13 of the OPU 10 with respect to the signal layer 520 of 500 F.

When the surface shake operation occurs on the optical disc 500 (FIG. 2), the focus adjustment of the OBL 13 and the focus tilt adjustment of the OBL 13 are performed simultaneously. When the surface wobbling operation occurs on the optical disc 500, the position of the OBL 13 is automatically adjusted along the vertical direction Da. At the same time, the posture of the OBL 13 is automatically adjusted so that the optical axis LBa of the laser light transmitted through the OBL 13 is inclined by an angle of −Af to + Af. As a result, the optical axis LBa of the laser beam is always kept orthogonal to the signal layer 520 of the optical disc 500F, and the spot formed by the laser beam being focused by the OBL 13 is shifted from the pit 510 that is being followed. That is avoided. Therefore, when the OPU 10 (FIG. 1) is used and data on the optical disc 500F is being read, it is easy to prevent the occurrence of a focus drop and a data reading error on the optical disc 500F.

  This optical disk apparatus tilt adjustment circuit generates a control adjustment signal for adjusting the angular deviation of the OBL 13 based on the jitter detected by the jitter measurement circuit 40 and transmits the control adjustment signal to the tilt signal adjustment circuits 71 and 72. It is comprised as what has the control part 80 to do.

  More specifically, the tilt adjustment circuit for the optical disc apparatus generates a control adjustment signal used when the angular deviation of the OBL 13 is adjusted based on the jitter detected by the jitter measurement circuit 40. The control adjustment signal Is provided with a system control microcomputer 80 for transmitting to the focus tilt signal adjustment circuit 71.

  If a tilt adjustment circuit for an optical disc apparatus including the system control microcomputer 80 is configured, the optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 is substantially orthogonal to the signal layer 520 of the optical disc 500. It becomes easy to be in a state. In the system control microcomputer 80 constituting the tilt adjustment circuit for the optical disc apparatus, a control adjustment signal used when the angular deviation of the OBL 13 is adjusted is generated based on the jitter detected by the jitter measurement circuit 40.

  The control adjustment signal is a signal for setting a gain such as how much the signal output from the focus tilt signal adjustment circuit 71 is amplified in the focus tilt signal adjustment circuit 71. Gain means the voltage or current ratio between the input and output of the amplifier. The gain is a value representing the amplification function of the amplifier, and the unit is expressed in decibels (dB). A control adjustment signal generated by the system control microcomputer 80 is transmitted to the focus tilt signal adjustment circuit 71, and the focus tilt signal adjustment circuit 71 adjusts a signal for adjusting the angular deviation of the OBL 13.

  The tilt adjustment circuit for the optical disk apparatus includes a front-end processing unit 30 that generates a tracking error signal from a signal detected by the PDIC 15 when a tracking error is about to occur in the OBL 13 of the OPU 10. .

  If the front end processing unit 30 is provided in the tilt adjustment circuit, it is easy to avoid the occurrence of a tracking error in the OBL 13 and a data reading error in the optical disc 500. Since the optical disc apparatus tilt adjustment circuit includes the front end processing unit 30 that generates a tracking error signal from the signal detected by the PDIC 15, the tracking error signal generated by the front end processing unit 30 A tracking error occurring in the OBL 13 of the OPU 10 is easily avoided.

  The optical disc apparatus tilt adjustment circuit includes a tracking servo circuit 42 that enables a tracking servo operation of a lens holder (not shown) including the OBL 13 to be executed based on the tracking error signal.

If the tracking servo circuit 42 is provided in the tilt adjustment circuit, it is easy to avoid the occurrence of a tracking error in the OBL 13 and a data reading error on the optical disc 500. The optical disk apparatus tilt adjustment circuit includes a tracking servo circuit 42 that enables the tracking servo operation of the lens holder including the OBL 13 to be executed based on the tracking error signal generated by the front end processing unit 30. When a tracking error is about to occur in the OBL 13 of the optical pickup device, a tracking servo operation is executed on the OBL 13. Therefore, the occurrence of an error in reading data on the optical disc 500 is easily prevented.

  The tracking servo circuit 42 is configured using an equalizer. As described above, an equalizer is an electric circuit for processing and adjusting the overall frequency characteristics of a signal such as an audio signal. The equalizer is abbreviated as “EQ”.

  The tilt adjustment circuit for the optical disk apparatus includes a tracking coil drive circuit 52 to which the tracking control signal output from the tracking servo circuit 42 is input. When the focal point of the laser beam LB focused by the OBL 13 is shifted with respect to the pit 510 of the optical disc 500 along the tracking direction Df of the OBL 13, a tracking coil drive is used to adjust the tracking of the OBL 13 of the OPU 10. A tracking drive signal is sent from the circuit 52 to the tracking coil 22 of the OPU 10. As a result, the occurrence of a tracking error in the optical pickup device 10 is easily avoided.

  The tilt adjustment circuit for the optical disc apparatus receives the tracking control signal TDO output from the tracking servo circuit 42, and extracts a signal corresponding to the rotation cycle Ct (FIG. 5) of the optical disc 500 based on the tracking control signal TDO. A tracking tilt bandpass filter circuit 62 (FIG. 1) is provided. TDO in this specification is an abbreviation for “tracking drive out”.

  If the tracking tilt bandpass filter circuit 62 is provided in the tilt adjustment circuit, the optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 is always substantially orthogonal to the signal layer 520 of the optical disc 500. To be easily maintained. The optical disk apparatus tilt adjustment circuit includes a tracking tilt bandpass filter circuit 62 that extracts a signal corresponding to the rotation period Ct of the optical disk 500 based on the tracking control signal TDO output from the tracking servo circuit 42. Therefore, based on the signal corresponding to the rotation period Ct of the optical disc 500, the optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 is always kept substantially orthogonal to the signal layer 520 of the optical disc 500. It becomes easy.

  The spindle motor drive circuit 230 rotates the spindle motor 250 and, for example, the spindle motor drive circuit 230 detects a rotation period signal of the optical disc 500. At this time, this signal is input to the tracking tilt bandpass filter circuit 62 via the filter characteristic changing circuit 210 that can change the filter characteristic of the tracking tilt bandpass filter circuit 62.

  The tilt signal adjustment circuits 71 and 72 include a tracking tilt signal adjustment circuit 72 that can adjust the level of the signal extracted by the tracking tilt bandpass filter circuit 62.

If the tracking tilt signal adjustment circuit 72 is provided in the tilt adjustment circuit, the optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 is always kept orthogonal to the signal layer 520 of the optical disc 500. It becomes easy to be done. The optical disc apparatus tilt adjustment circuit includes a tracking tilt signal adjustment circuit 72 that can adjust the level of the signal extracted by the tracking tilt bandpass filter circuit 62. The optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 is easily maintained in a state of being orthogonal to each other with high accuracy.

  This tilt adjustment circuit for an optical disc apparatus includes a filter characteristic changing circuit 210 that can change the filter characteristic of the tracking tilt bandpass filter circuit 62.

  If the filter characteristic changing circuit 210 capable of changing the filter characteristic of the tracking tilt bandpass filter circuit 62 is provided in the tilt adjusting circuit for the optical disc apparatus, the tracking tilt adjustment of the OBL 13 with respect to the optical disc 500 is easily performed satisfactorily. Become. As the optical disk 500, an optical disk 500 that is rotated in a state where the linear velocity is substantially constant when the optical disk 500 is rotated, that is, a so-called CLV optical disk 500 is generally used. When such information / data reading / writing of the optical disc 500 is performed, the number of revolutions of the OPU 10 in the vicinity of the inner peripheral portion 501 of the optical disc 500 at the time of reading / writing information / data of the OPU 10 Disc rotation speed is different when reading / writing information / data.

  By providing the filter characteristic changing circuit 210 that can change the filter characteristic of the tracking tilt bandpass filter circuit 62, the tracking tilt bandpass filter circuit 62 is changed from the filter characteristic changing circuit 210 even if the rotational speed of the optical disc 500 changes. Is sent to the tracking tilt bandpass filter circuit 62, and the characteristic of the tracking tilt bandpass filter circuit 62 is changed to the optimum state. Therefore, stable tracking tilt adjustment is performed even if the rotational speed of the optical disc 500 changes.

  The jitter signal output from the system control microcomputer 80 is input to the tracking tilt signal adjustment circuit 72.

  Further, the optical disk 500 is, for example, an eccentric disk 500T (FIGS. 4A and 4B), and the OBL 13 of the OPU 10 is swung substantially along the tracking direction Dt with respect to the signal layer 520 of the eccentric disk 500T. The tilt signal adjustment circuits 71 and 72 (FIG. 1) can correct the angular deviation of the OBL 13 based on the jitter when an angular deviation is generated in the OBL 13 of the OPU 10 with respect to the signal layer 520 of A tracking tilt signal adjustment circuit 72 is provided for generating.

  The OBL 13 of the OPU 10 is swung substantially along the tracking direction Dt with respect to the signal layer 520 of the eccentric disk 500T (FIGS. 4A and 4B), and the angle to the OBL 13 of the OPU 10 with respect to the signal layer 520 of the eccentric disk 500T. When the shift is about to occur, the tracking tilt signal adjustment circuit 72 (FIG. 1) generates a signal capable of correcting the angular shift of the OBL 13 based on the jitter.

  If such a tilt adjustment circuit for an optical disc apparatus is configured, even if the optical disc 500 provided in the optical disc apparatus 1 is an eccentric disc 500T, the signal is emitted from the LD 11 of the OPU 10 to the signal layer 520 of the optical disc 500T. Further, the optical axis LBa of the laser beam LB is always easily set to be orthogonal. The optical disc apparatus tilt adjustment circuit includes a tracking tilt signal adjustment circuit 72 that generates a signal capable of correcting the angular deviation of the OBL 13 based on the jitter detected by the jitter measurement circuit 40. It is easy to avoid the occurrence of an angular shift of the OBL 13 of the OPU 10 with respect to the signal layer 520 of 500T.

When an eccentric operation occurs in the optical disc 500 (FIGS. 4A and 4B), the tracking adjustment of the OBL 13 and the tracking tilt adjustment of the OBL 13 are performed simultaneously. When an eccentric operation occurs in the optical disc 500, the position of the OBL 13 is automatically adjusted along the disc inner / outer direction Db. At the same time, even if the optical axis LBa of the laser light transmitted through the OBL 13 is inclined by an angle of −At to + At, the posture of the OBL 13 is automatically adjusted. The optical axis LBa of the laser beam is always kept orthogonal to the signal layer 520 of the optical disc 500F, and the spot formed by the laser beam being narrowed by the OBL 13 is shifted from the following pit 510. Avoided. Therefore, (FIG. 1) When the OPU 10 is used and data on the optical disc 500T is being read, it is easy to prevent the occurrence of a focus drop and a data reading error on the optical disc 500T.

  The optical disc apparatus tilt adjustment circuit generates a control adjustment signal used when the angle deviation of the OBL 13 is adjusted based on the jitter detected by the jitter measurement circuit 40, and uses the control adjustment signal as a tracking tilt signal. A system control microcomputer 80 for transmission to the adjustment circuit 72 is provided.

  If a tilt adjustment circuit for an optical disc apparatus including the system control microcomputer 80 is configured, the optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 is substantially orthogonal to the signal layer 520 of the optical disc 500. It becomes easy to be in a state. In the system control microcomputer 80 constituting the tilt adjustment circuit for the optical disc apparatus, a control adjustment signal used when the angular deviation of the OBL 13 is adjusted is generated based on the jitter detected by the jitter measurement circuit 40.

  The control adjustment signal is a signal for setting a gain such as how much the signal output from the tracking tilt signal adjustment circuit 72 is amplified in the tracking tilt signal adjustment circuit 72. As described above, the gain means the voltage or current ratio between the input and output of the amplifier. The gain is a value representing the amplification function of the amplifier, and the unit is expressed in decibels (dB). A control adjustment signal generated by the system control microcomputer 80 is transmitted to the tracking tilt signal adjustment circuit 72, and the tracking tilt signal adjustment circuit 72 adjusts a signal for adjusting the angular deviation of the OBL 13.

  Further, the tilt adjustment circuit for the optical disc apparatus outputs an offset signal for correcting the angle deviation when the angle deviation is caused in the OBL 13 of the OPU 10 with respect to the signal layer 520 of the optical disc 500. 90. The offset adjustment circuit 90 performs skew correction in the radial direction of the optical disc 500, for example. As described above, the skew means “distortion” or “bend”.

  If the offset adjustment circuit 90 is provided in the tilt adjustment circuit, the optical axis LBa of the laser light LB emitted from the LD 11 of the OPU 10 is always easily orthogonal to the signal layer 520 of the optical disc 500. . The tilt adjustment circuit for the optical disc apparatus outputs an offset signal for correcting the angle shift of the OBL 13 when an angle shift is generated in the OBL 13 of the OPU 10 with respect to the signal layer 520 of the optical disc 500. 90, the angular deviation of the OBL 13 of the OPU 10 with respect to the signal layer 520 of the optical disc 500 is accurately corrected.

  An offset output control signal for outputting an offset signal from the offset adjustment circuit 90 based on the jitter is generated by the system control microcomputer 80, and the offset output control signal is transmitted from the system control microcomputer 80 to the offset adjustment circuit 90. Is done. The offset output control signal is a digital signal.

  If the offset output control signal is generated by the system control microcomputer 80 and the offset output control signal is transmitted to the offset adjustment circuit 90, tilt adjustment such as focus tilt adjustment of the OPU 10 can be performed accurately. It becomes easy to be done. Further, if the offset output control signal is generated by the system control microcomputer 80 and the offset output control signal is transmitted to the offset adjustment circuit 90, tilt adjustment such as tracking tilt adjustment of the OPU 10 can be performed. , Easy to be done accurately. When the digital offset output control signal is transmitted from the system control microcomputer 80 to the offset adjustment circuit 90, the offset signal is output from the offset adjustment circuit 90.

  The optical disc apparatus tilt adjustment circuit includes an addition circuit 100 that adds the offset signal output from the offset adjustment circuit 90 to the tilt adjustment signal output from each of the tilt signal adjustment circuits 71 and 72. Yes. More specifically, the optical disc apparatus tilt adjustment circuit includes a focus tilt adjustment signal output from the focus tilt signal adjustment circuit 71, a tracking tilt adjustment signal output from the tracking tilt signal adjustment circuit 72, and an offset adjustment circuit 90. Is provided with an adder circuit 100 for adding the offset signal output from. A focus tilt adjustment signal is output from the focus tilt signal adjustment circuit 71. A tracking tilt adjustment signal is output from the tracking tilt signal adjustment circuit 72. An offset signal is output from the offset adjustment circuit 90. These signals are combined by the adder circuit 100.

  If the adder circuit 100 is provided in the tilt adjustment circuit, the optical axis LBa of the laser beam LB emitted from the LD 11 of the OPU 10 with respect to the signal layer 520 of the optical disc 500 is easily maintained in a state of being accurately orthogonal. Become. The optical disc apparatus tilt adjustment circuit outputs a focus tilt adjustment signal output from the focus tilt signal adjustment circuit 71, a tracking tilt adjustment signal output from the tracking tilt signal adjustment circuit 72, and an offset adjustment circuit 90. Since the addition circuit 100 for adding the offset signal is provided, the addition circuit 100 generates a signal in which the focus tilt adjustment signal, the tracking tilt adjustment signal, and the offset signal are combined. . By this signal, the angle adjustment of the OBL 13 of the OPU 10 with respect to the signal layer 520 of the optical disc 500 is performed with high accuracy.

  The optical disc apparatus tilt adjustment circuit includes a tilt coil drive circuit 120 to which the addition signal output from the addition circuit 100 is input. In order to adjust the tilt of the OBL 13 of the OPU 10, a drive signal to be sent to the tilt adjustment coil 20 of the OPU 10 is generated by the tilt coil drive circuit 120 based on the addition signal.

  If the tilt coil drive circuit 120 is provided in the tilt adjustment circuit, the angle adjustment of the OBL 13 of the OPU 10 with respect to the signal layer 520 of the optical disc 500 is reliably performed. Based on the addition signal output from the adder circuit 100, a drive signal to be sent to the tilt adjustment coil 20 of the OPU 10 is generated by the tilt coil drive circuit 120. When an angle shift is about to occur in the OBL 13, the angle shift of the OBL 13 is corrected by a drive signal sent to the tilt adjustment coil 20 of the OPU 10.

  A state where the tilt control of the OPU 10 is performed will be described.

A servo signal is transmitted to the tilt coil 20 in order to perform focus adjustment and tracking adjustment of the OBL 13 of the OPU 10 (FIG. 1). As a result, the control of the OBL 13 is performed so that the optical axis LBa of the laser light LB emitted from the laser diode 11 and transmitted through the OBL 13 is perpendicular to the signal layer 520 of the disk 500.

  Such tilt control is performed to prevent focus drop. Further, control is performed on the signal layer 520 of the optical disc 500 so that the optical axis LBa of the laser light LB emitted from the laser diode 11 and transmitted through the OBL 13 is perpendicular. Thereby, the data reading performance of the objective lens 10 with respect to the data of the optical disc 500 is improved. What enables the tilt control is realized.

  As described above, defocusing means that the focal point of the laser beam LB emitted from the laser diode 11 of the OPU 10 and transmitted through the OBL 13 is shifted with respect to the pit 510 of the optical disc 500 that is being tracked. This means that the read data cannot be read.

  OBL13 is set by gain setting by bandpass filter circuits 61 and 62 for taking out only the rotation periods Cf (FIG. 3) and Ct (FIG. 5) of the optical disks 500F (FIG. 3) and 500T (FIG. 5), the jitter measuring circuit 40, and the like. To achieve the optimal tilting operation. The gain is set by using the surface deflection disk 500F (FIG. 2) or the eccentric disk 500T (FIG. 4). At that time, the gain is varied and the jitter is measured. As described above, the gain means the voltage or current ratio between the input and output of the amplifier. The gain is a value representing the amplification function of the amplifier, and the unit is expressed in decibels (dB). Further, as described above, jitter means subtle fluctuations or distortion of a signal.

  Further, when tilt control of the OBL 13 of the OPU 10 (FIG. 1) is performed, an FDO signal sent from the focus servo circuit 41 to the focus tilt bandpass filter 61, or sent from the tracking servo circuit 42 to the tracking tilt bandpass filter 62. Optimal tilt control is realized by the TDO signal. As described above, FDO is an abbreviation for “focus drive out”. TDO is an abbreviation for “tracking drive out”.

  By adjusting the gain by the tilt adjustment circuit for the optical disc apparatus, the tilt operation between the focus direction Df and the tracking direction Dt when the data of the optical disc 500 is read into the optical disc apparatus 1 using the OPU 10 is short. Done on time.

  The FDO signal is processed by the focus tilt bandpass filter 61. Further, the rotation period Cf of the optical disc 500 substantially along the focus direction Df (FIG. 3) is taken out by the focus tilt bandpass filter 61 (FIG. 1). The required gain for performing tilt control is adjusted based on jitter. Further, a current is passed through the tilt coil 20 based on the servo signal. By performing such control, the optical axis LBa of the laser beam LB emitted from the OPU 10 is maintained at a right angle with respect to the signal layer 520 of the optical disc 500.

  The TDO signal is processed by the tracking tilt bandpass filter 62. Further, the rotation period Ct of the optical disc 500 substantially along the focus direction Df (FIG. 5) is extracted by the tracking tilt bandpass filter 62 (FIG. 1). The required gain for performing tilt control is adjusted based on jitter. Further, a current is passed through the tilt coil 20 based on the servo signal. By performing such control, the optical axis LBa of the laser beam LB emitted from the OPU 10 is maintained at a right angle with respect to the signal layer 520 of the optical disc 500.

  The required gain setting can be easily adjusted by the inspection optical disks 500F and 500T (FIG. 1) such as the surface deflection disk 500F (FIG. 2) and the eccentric disk 500T (FIG. 4). In addition, since the TDO signal and the FDO signal are added to the tilt signal that has been used up to now, it is possible to use a signal that matches the characteristics so far. Further, since the optical axis LBa irradiated from the OPU 10 is always perpendicular to the signal layer 520 of the optical disc 500, not only the focus drop but also the data reading performance of the optical disc 500 is improved.

  A state in which the dynamic tilt control method is performed will be specifically described below.

  First, a state where focus adjustment is performed will be described. When surface vibration occurs in the optical disk 500 (FIG. 2) during disk reproduction or disk recording, the surface vibration component becomes an FDO signal (FIG. 1). When the FDO signal is flowed, the focus servo operation is executed.

  Here, when the dynamic tilt control method is not performed, the lens holder including the OBL 13 is not in an optimal posture only by the vertical movement of the lens holder by the focus coil 21. The optical axis LBa of the laser beam LB focused by the lens holder OBL 13 is not perpendicular to the signal layer 520 of the optical disc 500. Therefore, the FDO signal is set according to the surface shake rotation period Cf (FIG. 3) of the optical disc 500 (FIG. 1). In this case, a digital servo circuit is used.

  For example, if the optical disk 500 is of the CAV system, the OPU 10 is positioned on the inner peripheral side of the optical disk 500 when the optical disk 500 is rotated, or the OPU 10 is positioned on the outer peripheral side of the optical disk 500. In addition, the rotation period Cf (FIG. 3) of the optical disc 500 is constant.

  For example, when the optical disk 500 (FIG. 1) is of the CLV system, the rotation period Cf (FIG. 3) of the optical disk 500 is determined according to the linear velocity and the position of the OPU 10 with respect to the optical disk 500. Further, the frequency of the focus tilt bandpass filter 61 is set in accordance with the linear velocity and the position of the OBL 13 of the OPU 10 with respect to the optical disc 500 (FIG. 1). At that time, the calculated output value is multiplied by a coefficient to perform repeated calculation. Here, the coefficient is adjusted based on the jitter measured by the jitter measuring circuit 40. The coefficient is a gain.

  In this way, the optical axis LBa of the laser beam LB focused by the OBL 13 of the OPU 10 is adjusted to be perpendicular to the signal layer 520 of the disc. As a result, when a surface shake component is to be added to the signal read by the OPU 10, the posture of the lens holder of the OPU 10 is automatically adjusted with respect to the signal layer 520 of the optical disc 500, and the optical disc 500 is in an optimal state. The data is read.

  The coefficient range of FT_GAIN is set to 0000h to 8000h, jitter is measured, and the coefficient (gain) is adjusted. Servo adjustment is performed by reading the disk.

  A process when the gain, that is, the coefficient is adjusted will be described with reference to the flowchart shown in FIG. Here, a process in which a gain for focus tilt control is adjusted by jitter using a CD-type optical disc such as a CD-ROM or CD-R will be described.

First, the initial value 0000h is set in FT_GAIN (S601). Also, i is set to 0 (S601). Next, jitter is measured, and the result is stored in a memory (not shown) as jitter (i) (S602). Next, i is incremented (S603).
). Increment means to increase a numerical value by a predetermined size when an iterative process or the like is performed by programming. Also, 1000h is added to FT_GAIN (S603).

  When i is smaller than 8 (S604: No), jitter is measured again, and the result is stored in the memory as jitter (i). When i is smaller than 8, the process of S602 → S603 → S604 → S602 is repeated. Repeat calculation until i becomes 8 (S604: Yes).

  If i is set to 8, j is set to 0 (S605). Next, 0 × FFFF (maximum value) is input to jitter_min (S606). When jitter (j), which is a jitter measurement result, is smaller than jitter_min (S607: Yes), the jitter_min is set to jitter (j) (S608). Also, j is set to j_min (S608). In the determination of S607, when jitter (j) is equal to jitter_min (S607: No), or when jitter (j) is larger than jitter_min (S607: No), the processing of S608 is not performed. When j is smaller than 8 (S609: Yes), j is incremented (S610). When j is smaller than 8, the process of S607 → (S608) → S609 → S610 → S607 is repeated. When j = 8 (S609: No), 1000h × j_min is set to the optimum FT_GAIN (S611). In this way, the adjustment process ends.

  Next, the state when tracking adjustment is performed will be described. When the optical disk 500 (FIG. 4) is decentered during disk reproduction or disk recording, the decentered component becomes a TDO signal (FIG. 1). The tracking servo operation is executed by passing the TDO signal.

  Here, when the dynamic tilt control method is not performed, the lens holder including the OBL 13 is not in an optimum posture only by the movement of the lens holder in the disc outer periphery direction by the tracking coil 22. The optical axis LBa of the laser beam LB focused by the lens holder OBL 13 is not perpendicular to the signal layer 520 of the optical disc 500. Therefore, the TDO signal is set according to the eccentric rotation cycle Ct (FIG. 5) of the optical disc 500 (FIG. 1). In this case, a digital servo circuit is used.

  For example, if the optical disk 500 is of the CAV system, the OPU 10 is positioned on the inner peripheral side of the optical disk 500 when the optical disk 500 is rotated, or the OPU 10 is positioned on the outer peripheral side of the optical disk 500. In addition, the rotation cycle Ct (FIG. 5) of the optical disc 500 is constant.

  For example, when the optical disk 500 (FIG. 1) is of the CLV system, the rotation period Ct (FIG. 5) of the optical disk 500 is determined according to the linear velocity and the position of the OPU 10 with respect to the optical disk 500. Further, the frequency of the tracking tilt bandpass filter 62 is set according to the linear velocity and the position of the OBL 13 of the OPU 10 with respect to the optical disc 500 (FIG. 1). At that time, the calculated output value is multiplied by a coefficient to perform repeated calculation. Here, the coefficient is adjusted based on the jitter measured by the jitter measuring circuit 40. The coefficient is a gain.

In this way, the optical axis LBa of the laser beam LB focused by the OBL 13 of the OPU 10 is adjusted to be perpendicular to the signal layer 520 of the disc. Thus, when an eccentric component is added to the signal read by the OPU 10, the posture of the lens holder of the OPU 10 is automatically adjusted with respect to the signal layer 520 of the optical disc 500, and the optical disc 500 is in an optimal state. Data is read.

  The coefficient range of TT_GAIN is set to 0000h to 8000h, jitter is measured, and the coefficient (gain) is adjusted. Servo adjustment is performed by reading the disk.

  A process when the gain, that is, the coefficient is adjusted will be described with reference to the flowchart shown in FIG. Here, a process of adjusting the gain for tracking tilt control by jitter using a CD-type optical disk such as a CD-ROM or CD-R will be described.

  First, an initial value 0000h is set in TT_GAIN (S701). Further, 0 is set to i (S701). Next, jitter is measured, and the result is stored in a memory (not shown) as jitter (i) (S702). Next, i is incremented (S703). As described above, “increment” means that a numerical value is increased by a predetermined size when repetitive processing or the like is performed by programming. Also, 1000h is added to TT_GAIN (S703).

  When i is smaller than 8 (S704: No), jitter is measured again, and the result is stored in the memory as jitter (i). When i is smaller than 8, the process of S702 → S703 → S704 → S702 is repeated. The calculation is repeated until i becomes 8 (S704: Yes).

  If i is 8, j is set to 0 (S705). Next, 0 × TTTT (maximum value) is input to jitter_min (S706). When jitter (j), which is a jitter measurement result, is smaller than jitter_min (S707: Yes), the jitter_min is set to jitter (j) (S708). Also, j is set to j_min (S708). Further, in the determination of S707, when jitter (j) is equal to jitter_min (S707: No) or when jitter (j) is larger than jitter_min (S707: No), the processing of S708 is not performed. When j is smaller than 8 (S709: Yes), j is incremented (S710). When j is smaller than 8, the steps of S707 → (S708) → S709 → S710 → S707 are repeated. When j = 8 (S709: No), 1000h × j_min is set to the optimum TT_GAIN (S711). In this way, the adjustment process ends.

  The tilt adjustment circuit for the optical disk apparatus can be installed in an optical disk apparatus dedicated to data reading, for example, compatible with “CD-ROM”, “DVD-ROM”, and the like. Further, the tilt adjustment circuit for the optical disc apparatus is, for example, a read-only optical disc such as “CD-ROM” or “DVD-ROM”, or an additional recording such as “CD-R”, “DVD-R”, or “DVD + R”. Type optical discs and “CD-RW”, “DVD-RW”, “DVD + RW”, “DVD-RAM”, “HD-DVD”, “Blu ray Disc”, etc. It is possible to equip an optical disk device corresponding to the above.

The disk device 1 can be installed in, for example, a personal computer such as a notebook personal computer or a desktop personal computer, an audio device such as a CD player, or an audio / video device such as a DVD player. The The optical disk device 1 is compatible with a plurality of media such as a CD optical disk and a DVD optical disk. Media means media that records and mediates information and media that records and transmits information. The thing of this invention is not limited to what was illustrated. The thing of this invention can be changed variously in the range which does not deviate from the summary.

1 is a system configuration diagram showing an embodiment of a tilt adjustment circuit for an optical disc apparatus according to the present invention. FIG. It is explanatory drawing which shows the operation state of a surface shake disc. It is a wave form diagram which shows a rocking | fluctuation period when a surface shake disc is rotated. The operation state of an eccentric disk is shown, (a) is explanatory drawing which shows the state in which the objective lens was inclined toward the disk outer peripheral side of an eccentric disk, (b) is an objective toward the disk inner peripheral side of an eccentric disk. It is explanatory drawing which shows the state in which the lens was inclined. It is a wave form diagram which shows a rocking | fluctuation period when an eccentric disk is rotated. It is a flowchart which shows a process when focus tilt adjustment is performed. It is a flowchart which shows a process when tracking tilt adjustment is performed.

Explanation of symbols

1 Optical disk device 10 OPU (optical pickup device)
11 LD (light emitting device)
13 OBL (objective lens)
15 PDIC (light detector)
20 Tilt adjustment coil (tilt coil)
21 Focusing coil 22 Tracking coil 30 Front-end processing unit (optical output signal processing circuit)
40 Jitter Measuring Circuit 41 Focus Servo Circuit 42 Tracking Servo Circuit 51 Focus Coil Drive Circuit 52 Tracking Coil Drive Circuit 61 Focus Tilt Band Pass Filter Circuit (Band Pass Filter Circuit)
62 Tracking tilt bandpass filter circuit (bandpass filter circuit)
71 Focus tilt signal adjustment circuit (tilt signal adjustment circuit)
72 Tracking tilt signal adjustment circuit (tilt signal adjustment circuit)
80 Microcomputer (control unit)
90 Offset adjustment circuit 100 Addition circuit 120 Tilt coil drive circuit 210 Filter characteristic change circuit 230 Spindle motor drive circuit 250 Spindle motor 500 Optical disc (disc)
500F Surface runout disc (optical disc)
500T Eccentric disc (optical disc)
501 Inner peripheral portion 502 Outer peripheral portion 505 Disc surface 510 Pit (recording portion)
520 Signal layer (signal surface)
Af, At angle Cf, Ct Rotation period (rotation period)
Da disc vertical direction (vertical direction)
Da ₁ lower side direction Da ₂ upper side direction Db disc inside / outside direction (inside / outside direction)
Db ₁ Inner direction Db ₂ Outer direction Df Focus direction Dt Tracking direction FDO Focus control signal LB Laser light LBa Optical axis TDO Tracking control signal

Claims (13)

A tilt adjustment circuit for an optical disc device for causing an optical axis of a laser beam emitted from a light emitting element of an optical pickup device to be substantially orthogonal to a signal surface of the optical disc,
A jitter measurement circuit capable of measuring fluctuations in the signal detected by the photodetector of the optical pickup device;
When the objective lens of the optical pickup device is about to be deviated from the signal surface of the optical disc, the angular deviation of the objective lens is determined based on the jitter detected by the jitter measuring circuit. A tilt adjustment circuit for an optical disc apparatus, comprising: a tracking tilt signal adjustment circuit to be adjusted. An optical output signal processing circuit for outputting the signal detected by the photodetector as an RF signal to be a high frequency signal;
2. The tilt adjustment circuit for an optical disc apparatus according to claim 1, wherein when the RF signal is input to the jitter measurement circuit, the jitter is detected in response to fluctuation of the RF signal.   A tracking error signal is detected from the signal detected by the photodetector when a tracking error that causes the objective lens to shift in a direction substantially along the signal surface with respect to the recording portion of the optical disc is generated. A tilt adjustment circuit for an optical disc apparatus according to claim 1 or 2, further comprising an optical output signal processing circuit for generating   4. The tilt adjustment circuit for an optical disc apparatus according to claim 3, further comprising a tracking servo circuit that enables a tracking servo operation of the objective lens to be executed based on the tracking error signal.   A tracking tilt bandpass filter circuit that receives a tracking control signal output from the tracking servo circuit and extracts a signal corresponding to a rotation period of the optical disk based on the tracking control signal is provided. Item 5. The tilt adjustment circuit for an optical disc device according to Item 4.   6. The tilt adjustment circuit for an optical disc apparatus according to claim 5, wherein the tracking tilt signal adjustment circuit is capable of adjusting a level of a signal extracted by the tracking tilt bandpass filter circuit.   7. The tilt adjustment circuit for an optical disc apparatus according to claim 5, further comprising a filter characteristic changing circuit capable of changing a filter characteristic of the tracking tilt bandpass filter circuit. The optical disc is an eccentric disc,
The objective lens of the optical pickup device is swung substantially along the tracking direction with respect to the signal surface of the eccentric disc, and the angle of the objective lens of the optical pickup device with respect to the signal surface of the eccentric disc When a shift is about to occur,
8. The optical disc apparatus according to claim 1, wherein the tracking tilt signal adjustment circuit generates a signal capable of correcting the angular deviation of the objective lens based on the jitter. Tilt adjustment circuit. Based on the jitter detected by the jitter measurement circuit, a control adjustment signal used when the angular deviation of the objective lens is adjusted is generated, and the control adjustment signal is transmitted to the tracking tilt signal adjustment circuit. 9. The tilt adjustment circuit for an optical disc apparatus according to claim 1, further comprising a control unit that performs the control.   An offset adjustment circuit that outputs an offset signal for correcting the angular deviation when the objective lens of the optical pickup device is about to produce the angular deviation with respect to the signal surface of the optical disc; The tilt adjustment circuit for an optical disc apparatus according to any one of claims 1 to 9,   An offset output control signal for outputting the offset signal from the offset adjustment circuit based on the jitter is generated by a control unit, and the offset output control signal is transmitted from the control unit to the offset adjustment circuit. The tilt adjustment circuit for an optical disc apparatus according to claim 10.   12. The optical disc apparatus according to claim 10, further comprising an addition circuit that adds the offset signal output from the offset adjustment circuit to a tracking tilt adjustment signal output from the tracking tilt signal adjustment circuit. Tilt adjustment circuit. A tilt coil drive circuit to which the addition signal output from the addition circuit is input;
In order to adjust the angle of the objective lens of the optical pickup device, a drive signal sent to the tilt adjustment coil of the optical pickup device is generated by the tilt coil drive circuit based on the added signal. The tilt adjustment circuit for an optical disk device according to claim 12.

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