JP2008176900A - Optical disk device and its tilt value-setting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set an optimum tilt value in an optical disk device and in its tilt value-setting method. <P>SOLUTION: An optical disk device 1 is provided with: a jitter value-detecting circuit 9, which detects a jitter value, on the basis of a signal read out from an optical disk M; and a tilt value-setting circuit 23 which adjusts a tilt value, which is used for correcting an angle deviation of an objective lens 4 to the signal layer Ms of the optical disk M, when the focusing of the objective lens 4 is made to the optical disk M on the basis of the signal which passes through the jitter-detecting circuit 9, and executes tilt adjustment on the basis of the tilt value. By this, the optical disk device 1 sets the optimum tilt value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus capable of recording a signal on an optical disc by a laser beam irradiated from an optical pickup device and reproducing a signal recorded on the optical disc by a laser beam, and a tilt value setting method thereof.

Laser light emitted from an optical pickup device (OPU) of the optical disc apparatus is focused on the signal surface of the optical disc. Laser (LASER) is "light amplification by stimulated
Abbreviation for “emission of radiation”. There are various techniques for focusing laser light on the signal surface of an optical disk, so-called focus control techniques. There are various techniques for determining the focal position of laser light on a substantially spiral track provided on the signal surface of an optical disk, so-called tracking control techniques. In general, focus control and tracking control are performed using a signal obtained from a photodetector incorporated in an optical pickup device.

  Focus means, for example, focus or focus. Focusing means focusing or focusing. In addition, the track in this specification means, for example, a signal trajectory on an optical disc. Further, tracking means that light is used to trace and observe a minute signal portion provided on the signal surface of the optical disc, and the position of the orbit drawn in a substantially spiral shape is determined.

  The focus control is generally performed by a circuit called a focus servo circuit, and the displacement operation of the objective lens is performed based on, for example, a position that is the operation center of the objective lens. The tracking control is generally performed by a circuit called a tracking servo circuit, and the displacement operation of the objective lens is performed with reference to the position serving as the operation center of the objective lens, for example. The servo means, for example, a mechanism that automatically corrects and controls by measuring the state of the object to be controlled and comparing it with a predetermined reference value.

  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 disc device or 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”.

  For example, an arbitrary offset (OFFSET) can be applied by the tilt mechanism, and a system that adjusts the jitter (jitter) when reading data from the disc (DISC) is equipped with the tilt offset (TILE_OFFSET) so-called tilt (TILT). There is also an optical pickup device. Jitter means, for example, subtle fluctuations or distortion of a signal.

  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).

  For example, there is an optical pickup device in which the position of the operation center of the objective lens is adjusted by detecting a jitter value included in a signal such as a reproduction signal (see, for example, Patent Document 2).

Normally, in an optical pickup device, the tilt value is variable and the tilt value is set with an optimum jitter value. For example, an optical disc apparatus that always sets the tilt bias amount by calculation processing has been considered. Further, for example, an optical disc apparatus that sets the tilt bias amount based on the minimum value of the jitter value has been considered.
JP 2002-197698 A (pages 1, 2 and 1 to 3) Japanese Patent Laid-Open No. 7-262584 (pages 1, 2 and 1-6)

  In the conventional optical pickup device, the focus position controlled by the tilt operation is not necessarily the best focus position due to the individual difference of the optical pickup device itself or the individual difference of the optical disc, and the tilt operation is optimal. There was a problem that could not be done.

  In addition, for example, in an optical disc apparatus that sets the tilt bias amount by arithmetic processing, the tilt bias amount is set by arithmetic processing, so there is a concern that the time required for the setting processing becomes long.

  Further, for example, when the method of setting the tilt bias amount based on the minimum value of the jitter value is performed, the following problem is concerned. For example, some optical discs used have very little change in jitter value. The bias amount set in the case of such an optical disc may be the tilt bias amount at the end of the detection range. When the tilt bias amount is set in this way, there is a problem that the tilt operation becomes unstable.

  When the tilt value is adjusted by the optical pickup device, there is an optical disc in which the jitter value corresponding to the tilt value hardly changes, or even when the tilt value is set to 0, the read jitter value is stable. If a tilt value biased so as to correspond to the optimum jitter is set for such an optical disc, the servo may become unstable due to the tilt value, and servo failure may occur.

  For example, when tilt adjustment is performed on the basis of detected jitter, servo failure may occur in an optical pickup device with little jitter change. When tilt adjustment is performed, there is a possibility that the optical pickup apparatus with little jitter change is set with a tilt value that is away from the center value corresponding to the operation center of the objective lens. In the optical pickup device in which such setting is performed, servo failure may occur.

  In addition, when tilt adjustment is performed in the optical pickup device, if a value other than 0 is set as the tilt value, servo failure is likely to occur when the optical pickup device performs a track jump with respect to the optical disc. was there.

  The present invention is to solve the above-described problems. An object of the present invention is to provide an optical disc apparatus capable of setting an optimum tilt value and a tilt value setting method thereof in view of the above points.

  In order to achieve the above object, an optical disc apparatus according to claim 1 of the present invention passes through a jitter value detection circuit for detecting a jitter value based on a signal read from the optical disc, and the jitter value detection circuit. Based on the signal, when the objective lens is focused on the optical disc, the tilt value used for correcting the angular deviation of the objective lens with respect to the signal layer of the optical disc is adjusted, and based on the tilt value. And a tilt value setting circuit for performing tilt adjustment.

  With the above configuration, an optical disc apparatus capable of setting an optimum tilt value is configured. Jitter means, for example, subtle fluctuations or distortion of a signal. In addition, the tilt in the optical disc device means, for example, an angular deviation between the signal layer of the optical disc and the optical axis of the laser beam emitted from the optical pickup device. An optimum tilt value is set in the optical disc apparatus based on the jitter value detected based on the signal read from the optical disc and the tilt value based on the detected jitter value.

  A tilt value setting method for an optical disc apparatus according to a second aspect of the invention is to detect a jitter value of a signal read from an optical disc using an optical disc apparatus provided with an optical pickup device having an objective lens, and to set the jitter value to the jitter value. Based on this, when the objective lens is focused on the optical disc, the tilt value used for correcting the angular deviation of the objective lens with respect to the signal layer of the optical disc is adjusted, and the objective lens with respect to the optical disc is adjusted. A tilt value setting method for an optical disc apparatus for performing tilt adjustment, wherein the jitter value is changed each time the tilt value is changed stepwise within a predetermined range of values including a reference value of the tilt value as necessary. Based on the difference between the maximum and minimum jitter values for each detected jitter value, the optimum tilt value is set. Characterized in that to.

  With the above configuration, an optimum tilt value is set for the optical disc apparatus. If necessary, the jitter value is detected every time the tilt value is changed stepwise within a predetermined range of values including the reference value of the tilt value, and the maximum jitter value and the minimum jitter value in each detected jitter value are determined. Since the optimum tilt value is set based on the difference value, the optimum tilt value is set for the optical disc apparatus.

  According to a third aspect of the present invention, there is provided a tilt value setting method for an optical disc device, a jitter value detection circuit for detecting a jitter value based on a signal detected by a photodetector provided in an optical pickup device, and the jitter value detection circuit. When the objective lens of the optical pickup device is focused on the optical disc based on the signal passing through the optical disc, the tilt value used to correct the angular deviation of the objective lens with respect to the signal layer of the optical disc is adjusted. A tilt value setting method for an optical disc device that performs tilt adjustment of the objective lens with respect to the optical disc using an optical disc device that includes a tilt value setting circuit that performs tilt adjustment based on the tilt value, When the signal is read from the optical disc and the jitter value is detected, the tilt value is The jitter value is detected each time the tilt value is changed stepwise within a predetermined range of values including a reference value, and based on the difference between the maximum jitter value and the minimum jitter value in each detected jitter value. And an optimum tilt value is set.

  With the above configuration, an optimum tilt value is set for the optical disc apparatus. If necessary, the jitter value is detected every time the tilt value is changed stepwise within a predetermined range of values including the reference value of the tilt value, and the maximum jitter value and the minimum jitter value in each detected jitter value are determined. Since the optimum tilt value is set based on the difference value, the optimum tilt value is set for the optical disc apparatus. Since an optimum tilt value is set for the optical disc apparatus, the optical pickup apparatus performs a stable tilt operation with respect to the optical disc.

  The tilt value setting method for an optical disc device according to claim 4 is the tilt value setting method for an optical disc device according to claim 2 or 3, wherein a difference value between the maximum jitter value and the minimum jitter value is predetermined. When the value is larger than the value, the tilt value corresponding to the minimum jitter value is set as the optimum tilt value.

With the above configuration, the optical pickup device that constitutes the optical disc apparatus performs a stable tilt operation on the optical disc. An optical disc in which the difference between the maximum jitter value and the minimum jitter value is larger than a predetermined value is an optical disc with poor jitter characteristics. When a signal is read from an optical disc with poor jitter characteristics, the tilt value corresponding to the minimum jitter value is set as the optimum tilt value, so that a stable tilt operation is executed by the optical pickup device.

  The tilt value setting method for an optical disc apparatus according to claim 5 is the tilt value setting method for an optical disc apparatus according to any one of claims 2 to 4, wherein a difference value between the maximum jitter value and the minimum jitter value is set. The reference value of the tilt value is set as the optimum tilt value when the value is smaller than a predetermined value set in advance.

  With the above configuration, the optical pickup device that constitutes the optical disc apparatus performs a stable tilt operation on the optical disc. An optical disc in which the difference between the maximum jitter value and the minimum jitter value is set to a small value equal to or less than a predetermined value is an optical disc having good jitter characteristics. When a signal is read from an optical disc with good jitter characteristics, the optical disc apparatus is set with the reference value of the tilt value as the optimum tilt value, so that a stable tilt operation can be performed without causing trouble in the tilt operation of the optical pickup device. It is executed by the type pickup device.

  The tilt value setting method for an optical disc apparatus according to claim 6 is the tilt value setting method for an optical disc apparatus according to any one of claims 2 to 5, wherein the tilt adjustment of the objective lens is performed on the optical disc. When the jitter value is first detected based on the reference value of the tilt value, and the detected jitter value is larger than a predetermined jitter value, the tilt value The jitter value is detected every time the tilt value is changed stepwise within the predetermined range of values including the reference value.

  With the above configuration, an optimum tilt value corresponding to the optical disc is set in the optical disc apparatus. When the tilt adjustment of the objective lens is performed on the optical disc, first, a jitter value based on the reference value of the tilt value is detected. An optical disc in which the jitter value based on the reference value of the tilt value is larger than a predetermined jitter value is an optical disc that needs to investigate each jitter value corresponding to each tilt value. When the jitter value based on the detected reference value of the tilt value is larger than a predetermined predetermined jitter value, the tilt value is stepped within a predetermined range of values including the reference value of the tilt value. Each time a change is made, the jitter value is detected, and an optimum tilt value corresponding to the optical disc is set based on the difference between the maximum jitter value and the minimum jitter value in each detected jitter value.

  The tilt value setting method for an optical disc device according to claim 7 is the tilt value setting method for an optical disc device according to any one of claims 2 to 6, wherein the tilt adjustment of the objective lens is performed on the optical disc. Sometimes, when the jitter value is first detected based on the reference value of the tilt value, and the detected jitter value is smaller than a predetermined jitter value, the tilt value is detected. The reference value of the tilt value is set as the optimum tilt value without causing the jitter value to be detected every time the tilt value is changed stepwise within the numerical value within the predetermined range including the reference value of It is characterized by that.

With the above configuration, when an optical disc with good jitter characteristics is used, the tilt value is quickly set, and the optical pickup device constituting the optical disc apparatus performs a stable tilt operation on the optical disc. Become. When the tilt adjustment of the objective lens is performed on the optical disc, first, a jitter value based on the reference value of the tilt value is detected. An optical disc in which the jitter value based on the reference value of the tilt value is a small value equal to or smaller than a predetermined jitter value is determined as an optical disc with good jitter characteristics. When a signal is read from an optical disk with good jitter characteristics, the tilt value reference value is not detected every time the tilt value is changed stepwise within a predetermined range of values including the tilt value reference value. Since the optimum tilt value is set, the time for setting the tilt value is shortened. In addition, when a signal is read from an optical disc with good jitter characteristics, the optical disc apparatus is set with the reference value of the tilt value as an optimum tilt value, so that stable tilt operation can be performed without causing any trouble in the tilt operation of the optical pickup device. Is executed by the optical pickup device.

  The tilt value setting method for an optical disc apparatus according to claim 8 is the tilt value setting method for an optical disc apparatus according to any one of claims 2 to 7, wherein the optimum tilt value is set to the numerical value other than the reference value. When set, the tilt value is set to the reference value when the optical pickup device performs a track jump on the optical disc.

  With the above configuration, even when a numerical value other than the reference value of the tilt value is set as the optimum tilt value, the track jump of the optical pickup device with respect to the optical disc is performed well. If the tilt adjustment of the optical pickup device with respect to the optical disc is performed and the tilt value is set to a value other than the reference value, the servo failure is likely to occur when the track jump of the optical pickup device with respect to the optical disc is performed. It was. However, even when the tilt value is set to a value other than the reference value, when the optical pickup device performs track jump, the tilt value is set to the reference value, so that the optical pickup device for the optical disc is set. The track jump is easily performed normally.

  The tilt value setting method for an optical disc apparatus according to claim 9 is the tilt value setting method for an optical disc apparatus according to claim 8, wherein the tilt value is set after the track jump of the optical pickup device to the optical disc is completed. Is returned to the numerical value other than the reference value.

  With the above configuration, the optimum tilt value for the optical disc apparatus is set again. When the optical pickup device does not perform track jump on the optical disc, the optical disc device is again set to a value other than the reference value of the tilt value as the optimum tilt value. Done.

  An optical disc apparatus according to a tenth aspect is characterized in that, in the optical disc apparatus according to the first aspect, the tilt value setting method of the optical disc apparatus according to any one of the second to ninth aspects is executable. .

  With the above configuration, it is possible to provide an optical disc apparatus capable of setting an optimum tilt value.

  As described above, according to the first aspect of the present invention, an optical disc apparatus capable of setting an optimum tilt value can be configured. Based on the jitter value detected based on the signal read from the optical disc and the tilt value based on the detected jitter value, an optimal tilt value can be set in the optical disc apparatus.

  According to the second aspect of the present invention, the optimum tilt value can be set in the optical disc apparatus. If necessary, the jitter value is detected every time the tilt value is changed stepwise within a predetermined range of values including the reference value of the tilt value, and the maximum jitter value and the minimum jitter value in each detected jitter value are determined. Since the optimum tilt value is set based on the difference value, the optical disc apparatus can be set with the optimum tilt value.

According to the invention described in claim 3, it is possible to set an optimum tilt value in the optical disc apparatus. If necessary, the jitter value is detected every time the tilt value is changed stepwise within a predetermined range of values including the reference value of the tilt value, and the maximum jitter value and the minimum jitter value in each detected jitter value are determined. Since the optimum tilt value is set based on the difference value, the optical disc apparatus can be set with the optimum tilt value. Since an optimum tilt value is set for the optical disc apparatus, the optical pickup apparatus performs a stable tilt operation on the optical disc.

  According to the fourth aspect of the present invention, the optical pickup device constituting the optical disc apparatus performs a stable tilt operation on the optical disc. An optical disc in which the difference between the maximum jitter value and the minimum jitter value is larger than a predetermined value is an optical disc with poor jitter characteristics. When a signal is read from an optical disk with poor jitter characteristics, the tilt value corresponding to the minimum jitter value is set as the optimum tilt value, so that a stable tilt operation can be executed by the optical pickup device.

  According to the fifth aspect of the present invention, the optical pickup device that constitutes the optical disc apparatus performs a stable tilt operation on the optical disc. An optical disc in which the difference between the maximum jitter value and the minimum jitter value is set to a small value equal to or less than a predetermined value is an optical disc having good jitter characteristics. When a signal is read from an optical disc with good jitter characteristics, the optical disc apparatus is set with the reference value of the tilt value as the optimum tilt value, so that stable tilt operation can be performed without causing trouble in the tilt operation of the optical pickup device. The optical pickup device can be executed.

  According to the sixth aspect of the present invention, the optimum tilt value corresponding to the optical disc can be set in the optical disc apparatus. When the tilt adjustment of the objective lens is performed on the optical disc, first, a jitter value based on the reference value of the tilt value is detected. An optical disc in which the jitter value based on the reference value of the tilt value is larger than a predetermined jitter value is an optical disc that needs to investigate each jitter value corresponding to each tilt value. When the jitter value based on the detected reference value of the tilt value is larger than a predetermined predetermined jitter value, the tilt value is stepped within a predetermined range of values including the reference value of the tilt value. Each time a change is made, the jitter value is detected, and an optimum tilt value corresponding to the optical disc is set based on the difference between the maximum jitter value and the minimum jitter value in each detected jitter value.

  According to the seventh aspect of the present invention, when an optical disc with good jitter characteristics is used, the tilt value can be set quickly, and the optical pickup device constituting the optical disc apparatus can , Perform a stable tilt operation. When the tilt adjustment of the objective lens is performed on the optical disc, first, a jitter value based on the reference value of the tilt value is detected. An optical disc in which the jitter value based on the reference value of the tilt value is a small value equal to or smaller than a predetermined jitter value is determined as an optical disc with good jitter characteristics. When a signal is read from an optical disk with good jitter characteristics, the tilt value reference value is not detected every time the tilt value is changed stepwise within a predetermined range of values including the tilt value reference value. Since the optimum tilt value is set, the time for setting the tilt value can be shortened. In addition, when a signal is read from an optical disc having good jitter characteristics, the optical disc apparatus is set with the reference value of the tilt value as the optimum tilt value, so that stable tilt without causing any trouble in the tilt operation of the optical pickup device. The operation can be executed by the optical pickup device.

According to the eighth aspect of the present invention, even if a numerical value other than the reference value of the tilt value is set as the optimum tilt value, the track jump of the optical pickup device with respect to the optical disc can be performed satisfactorily. If the tilt adjustment of the optical pickup device with respect to the optical disc is performed and the tilt value is set to a value other than the reference value, the servo failure is likely to occur when the track jump of the optical pickup device with respect to the optical disc is performed. It was. However, even when the tilt value is set to a value other than the reference value, when the optical pickup device performs track jump, the tilt value is set to the reference value, so that the optical pickup device for the optical disc is set. It is possible to facilitate the normal track jump.

  According to the ninth aspect of the present invention, the optimum tilt value can be set again in the optical disc apparatus. When track jump of the optical pickup device is not performed on the optical disc, numerical values other than the reference value of the tilt value are again set as the optimum tilt value in the optical disc device, so that the tilt adjustment of the objective lens with respect to the optical disc is performed well. Can be made.

  According to the invention described in claim 10, it is possible to provide an optical disc apparatus capable of setting an optimum tilt value.

  Hereinafter, an embodiment of an optical disc device and a tilt value setting method thereof according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of an optical disc apparatus according to the present invention, FIG. 2 is an explanatory view showing an operating state of a surface runout disk equipped in the optical disc apparatus, and FIG. FIG. 4 shows the operating state of the eccentric disk equipped in the optical disk apparatus, and FIG. 4A shows the objective lens tilted toward the disk outer peripheral side of the eccentric disk. FIG. 5B is an explanatory diagram showing a state in which the objective lens is tilted toward the inner circumferential side of the eccentric disk, and FIG. 5 is a swing cycle when the eccentric disk is rotated. FIG. 6 is a flowchart showing an embodiment of a tilt value setting method of the optical disc apparatus according to the present invention, FIG. 7 is a graph showing the relationship between the tilt value and the jitter value, and FIG. And the jitter value FIG. 9 is a graph showing the relationship between the tilt value and the jitter value, FIG. 10 is a graph showing the relationship between the tilt value and the jitter value, and FIG. 11 is a graph showing the relationship between the tilt value and the jitter value. It is a graph which shows.

  The optical disc apparatus 1 shown in FIG. 1 is configured to be able to set a tilt value suitable for performing a tilt operation using a jitter value of a signal obtained from the optical disc M. As described above, jitter means, for example, subtle fluctuations or distortion of a signal. The tilt in the optical disc device 1 or the optical pickup device 2 is, for example, the light of the laser light L emitted from the signal layer Ms of the optical disc M and the light emitting element 3 of the optical pickup device 2 and transmitted through the objective lens 4. This means an angular deviation from the axis La (FIGS. 1, 2, and 4A and 4B).

  An optical pickup device 2 built in the optical disc device 1 (FIG. 1) is used to reproduce or record data such as information on the optical disc M. As the optical disk M, for example, “CD” series optical disks, “DVD” (registered trademark) series optical disks, “HD DVD” (registered trademark) series optical disks, and “Blu-ray Disc” (registered trademark) series Optical discs and the like. “CD” is an abbreviation for “Compact Disc” (trademark). “DVD” is an abbreviation for “Digital Versatile Disc” (registered trademark). “HD DVD” is an abbreviation for “High Definition DVD” (registered trademark).

On the signal surface portion Ms of the optical disc M, a signal portion Mt for storing each data on the optical disc M is provided. The signal surface portion Ms of the optical disk is handled as a substantially planar signal layer surface, a substantially planar recording layer surface, or the like. The signal portion Mt of the optical disc M is formed as many fine pits Mt. A pit means a hole or a dent. When the disk-shaped optical disk M is viewed in plan, many fine pits Mt are arranged in a spiral shape. When the optical disc M is viewed from the signal surface portion Ms side of the optical disc M, the pit Mt row has a spiral shape. Since each pit Mt is very small, each pit Mt is not visible. In FIG. 1, FIG. 2, and FIG. 4, the signal layer Ms of the optical disk M and the pit Mt are shown using a broken line for convenience. In place of the pit Mt, for example, an optical disc M provided with a groove (not shown) capable of recording each signal can be used as the signal portion Mt of the optical disc M. A groove means an elongated dent.

  An optical disk M is placed on a turntable (not shown) that is rotationally driven by a spindle motor (not shown). In addition, the optical pickup device 2 is equipped with a light emitting element 3 that irradiates the optical disk M with a light beam L that is a laser beam L. The optical pickup device 2 is equipped with an objective lens 4 that narrows down the light beam L emitted from the laser diode 3 and irradiates the signal surface portion Ms of the optical disk M. When the laser beam L is narrowed down by the objective lens 4, a focused spot Ls is irradiated and formed on the signal surface portion Ms of the optical disc M.

  Further, the optical pickup device 2 is equipped with a photodetector 5 that receives the light beam L reflected from the signal surface portion Ms of the optical disk M. The light detector 5 receives the laser light L reflected from the signal surface portion Ms of the optical disk M, converts the signal into an electric signal, and detects information recorded on the signal surface portion Ms of the optical disk M. ing. The photodetector 5 receives the laser light L reflected from the signal surface portion Ms of the optical disc M, converts the signal into an electric signal, and forms a lens holder with an objective lens 4 (not shown) constituting the optical pickup device 2. ) Servo mechanism (not shown) is operated. As described above, the servo means, for example, a mechanism that automatically corrects and controls by measuring the state of the control target and comparing it with a predetermined reference value.

  Further, the optical pickup device 2 includes a focusing coil 71 that displaces the objective lens 4 substantially along a direction Df perpendicular to the surface Mf of the optical disk M, and the objective lens 4 substantially along the radial direction Dt of the optical disk M. The objective lens 4 is tilted in response to the tilting fluctuation of the optical disk M generated when the tracking coil 72 to be displaced and the optical disk M (FIG. 2) are rotating, or the optical disk M (FIGS. 4A and 4B). ) Is rotated, and the tilt coil 73 (FIG. 1) is provided to tilt the objective lens 4 in response to the roll of the optical disk M substantially along the radial direction Dt of the optical disk M. ing. The definitions relating to the directions Df and Dt such as the focusing direction Df or the tracking direction Dt in this specification are definitions for convenience for explaining the optical disc device 1 and the optical pickup device 2.

  As described above, the focus means focus or focus. Focusing means focusing or focusing. In addition, tracking means tracking and observing minute pits (holes, dents) Mt, grooves (grooves), wobbles (meanders) provided on the signal surface portion Ms of the optical disk M using light, This means that the position of the orbit drawn in a substantially spiral shape is determined. Wobble means meandering of tracks on which data signals such as information are recorded.

When reading / writing data / information on the optical disc M, the optical pickup device 2 of the optical disc apparatus 1 moves substantially along the inside / outside direction Db of the rotating optical disc M. Further, when the focusing adjustment of the objective lens 4 of the optical pickup device 2 is performed with respect to the rotating optical disc M, the objective lens 4 is usually finely moved along the vertical direction Da of the disc, so that the position of the objective lens 4 is increased. Adjustments are made. The disc vertical direction Da means, for example, a direction perpendicular to the disc surface Mf formed from the inner peripheral portion Mc to the outer peripheral portion Md of the optical disc M when the optical disc M is maintained in a substantially horizontal state. The disc surface Mf of the optical disc M is formed substantially parallel to the signal surface portion Ms of the optical disc M.

The state when the focusing adjustment of the objective lens 4 with respect to the optical disc M is performed will be described in detail. The objective lens 4 is moved slightly along the upper direction Da ₂ or the lower direction Da ₁ of the optical disc M (FIG. 2). The laser light spot Ls that has passed through the objective lens 4 is focused on the signal portion Mt of the optical disk M.

  Further, when the tracking adjustment of the objective lens 4 of the optical pickup device 2 is performed on the rotating optical disc M (FIG. 1), the objective lens 4 is usually finely moved along the disc inside / outside direction Db. The position of the lens 4 is adjusted. The disc inner / outer direction Db means, for example, a direction along the disc surface Mf between the inner peripheral portion Mc and the outer peripheral portion Md of the optical disc M when the optical disc M is maintained in a substantially horizontal state.

The state when tracking adjustment of the objective lens 4 with respect to the optical disc M will be described in detail. The objective lens 4 is moved slightly along the outer direction Db ₂ or the inner direction Db ₁ of the optical disc M (FIG. 4). The laser light spot Ls transmitted through the objective lens 4 is aligned with the signal portion Mt of the optical disk M.

  In this specification, the definitions relating to each direction such as “upper”, “lower”, “inner”, “outer”, and the like are definitions for convenience in describing the optical disc apparatus 1, the optical pickup apparatus 2, and the optical disc M.

  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. A laser diode is abbreviated as LD. The objective lens is abbreviated as “OBL”. The photo detector / photo diode IC is abbreviated as “PD” or “PDIC”.

  The OPU 2 includes the LD 3, the OBL 4, the lens holder, the PDIC 5, the focusing coil 71, the tracking coil 72, and the tilt coil 73. The OPU 2 is moved substantially along the radial direction Dt of the optical disc M by a feed motor (not shown) that can drive the pickup apparatus main body. Depending on the design / specifications of the OPU 2, the OPU 2 constituting the optical disc apparatus 1 is further provided with the feeding motor.

  The optical disc apparatus 1 includes an optical output signal processing circuit 6 that receives a signal detected by the PDIC 5 installed in the OPU 2 and outputs the signal detected by the PDIC 5 as a high frequency signal, for example, as an RF signal. 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”.

  A signal converted from an optical signal to an electric signal by the PDIC 5 installed in the OPU 2 is input to an optical output signal processing circuit 6 so-called front end processing unit 6. The front-end processing unit 6 is configured to generate and output a high-frequency signal such as an RF signal that is a reproduction signal of the signal recorded on the optical disc M, a focusing error signal, and a tracking error signal. Yes.

A focusing error is a light L focused by OBL 4 along a direction Df substantially perpendicular to the signal layer Ms such as the optical axis direction Df with respect to a pit Mt or groove (not shown) of the optical disc M. This means that the focal point Ls of the lens is displaced. A tracking error is a positional deviation of the focus Ls of the light L focused by the OBL 4 in the direction Dt substantially along the signal layer Ms such as the radial direction Dt with respect to the pit Mt or groove of the optical disc M. It means to cause.

  The optical disc apparatus 1 amplifies the signal detected by the photodetector 5 and converted to a high frequency signal by the optical output signal processing circuit 6, and also converts the high frequency analog signal into a digital signal. A circuit 7 is provided. More specifically, the optical disc apparatus 1 amplifies a signal detected by the PDIC 5 and converted into an RF signal by the front-end processing unit 6, and also converts an RF signal, which is an analog signal, into a digital signal. A processing circuit 7 is provided. Analog means expressing a state of a substance or a system by a physical quantity that continuously changes. Digital means expressing a state of a substance or a system by signals such as discrete numbers and characters.

  A high-frequency signal such as an RF signal that is a reproduction signal generated by the front-end processing unit 6 is input to a signal processing circuit 7 such as an RF signal amplification / processing circuit 7. A signal processing circuit 7 such as the RF signal amplification / processing circuit 7 amplifies a high frequency signal such as an RF signal. The signal processing circuit 7 such as the RF signal amplification / processing circuit 7 is configured to output an input analog signal as a binarized signal, so-called digital signal. Based on the signal output from the signal processing circuit 7 such as the RF signal amplification / processing circuit 7, the jitter value is satisfactorily detected.

  The optical disc apparatus 1 further includes a digital signal processing circuit 8 that demodulates the digital signal output from the signal processing circuit 7 such as the RF signal amplification / processing circuit 7. The digital signal output from the signal processing circuit 7 such as the RF signal amplification / processing circuit 7 is input to the digital signal processing circuit 8. The digital signal processing circuit 8 is configured to demodulate various signals.

  The optical disc apparatus 1 also includes a jitter value detection circuit 9 that detects a jitter value that is a signal fluctuation value based on a signal read from the optical disc M by the PDIC 5 of the OPU 2 having the OBL 4. More specifically, the optical disc apparatus 1 has a jitter value which is a signal fluctuation value based on a signal obtained from a digital signal processing circuit 8 through a signal processing circuit 7 such as an RF signal amplification / processing circuit 7. A jitter value detection circuit 9 for detecting the so-called jitter measurement circuit 9 is provided.

  The signal generated by the digital signal processing circuit 8 is input to the jitter measurement circuit 9. For example, when the optical disc M is a CD standard optical disc, the jitter measurement circuit 9 detects a signal having a length of 3T to 11T, and based on the reference clock signal, the time variation of the frequency of the reproduction signal, that is, the jitter value. Is detected. The smaller the jitter value detected by the jitter measuring circuit 9, the smaller the time variation and the better the reproduction characteristics.

  When a synchronous signal is detected from a high-frequency signal such as an 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 a reference CLK, for example. The signal length of the synchronous system will be described, for example, 3T to 11T for the CD series and 3T to 14T for the DVD series.

The optical disc apparatus 1 also includes a system control circuit 10 that receives the signal output from the jitter measurement circuit 9 and controls the entire optical disc apparatus 1. Various controls / operations of the optical disc device 1 and the OPU 2 are performed by the system control circuit 10. The system control circuit 10 is configured by a microcomputer. A micro computer means a micro computer.

  The system control microcomputer is a CPU, a system controller, a microprocessor, a microcomputer, or the like, and is a control unit 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 CPU 10 is realized by software so-called programs.

  The optical disc apparatus 1 further includes a first memory circuit 11 in which a program for causing the CPU 10 to perform various controls is stored. Each function implemented by software is stored in the first memory circuit 11 accessible by the CPU 10. The system control circuit 10 is configured to perform various controls / operations based on a program stored in the first memory circuit 11 such as a flash ROM. “ROM” is an abbreviation for “read-only memory”. As the first memory circuit 11, for example, a flash memory is used.

  The first memory circuit 11 will be described in detail. Examples of the first memory circuit 11 include a ROM such as an EEPROM. ROM means read-only memory. The EEPROM means a ROM whose contents can be electrically rewritten. The EEPROM is a so-called nonvolatile memory. When the EEPROM is changed, a voltage higher than a normal voltage is used. The EEPROM is capable of electrically erasing stored information. “EEPROM” is an abbreviation for “Electronically Erasable and Programmable Read Only Memory”.

  The first memory circuit 11 may be a ROM such as an EPROM. An EPROM means a ROM that can be erased and written any number of times. EPROM is performed by a special method different from that at the time of reading when the memory is erased. “EPROM” is an abbreviation for “Erasable Programmable Read Only Memory”.

  The optical disc apparatus 1 also includes a second memory circuit 12 that can store and erase various values input to the CPU 10. For example, a RAM is used as the second memory circuit 12. The RAM means a storage device that can access data in substantially the same time regardless of the storage location or order. “RAM” is an abbreviation for “random access memory”. The system control circuit 10 controls the operation of the second memory circuit 12 such as a RAM. The second memory circuit 12 is configured to be able to store a tilt value and a jitter value corresponding to the tilt value.

  In addition, the optical disc apparatus 1 performs OBL4 focusing on the signal plane portion Ms of the optical disc M when the OBL4 of the OPU 2 is focused on the signal plane portion Ms of the optical disc M based on the signal passing through the jitter measuring circuit 9 and the CPU 10. And a tilt value setting circuit 23 for adjusting the tilt value used for correcting the angle deviation and adjusting the tilt based on the adjusted tilt value.

An appropriate tilt value is set by the tilt value setting circuit 23. The tilt value setting circuit 23 is configured to be controlled by the system control circuit 10. When an operation for setting a tilt value suitable for the optical disk (M) is performed in the optical disk apparatus 1 after the optical disk (M) is installed in the optical disk apparatus 1, for example, a tilt that is used as a reference value For the value 0, the set tilt value is changed in steps of 2% from -8% to + 8%, for example.

  In this specification, an optical disc M having good jitter characteristics and an optical disc (M) that is estimated / determined that jitter characteristics are not good and each jitter value needs to be detected / inspected are, for example, parentheses ( ) Are shown separately.

  The optical disc apparatus 1 further includes a focusing servo circuit 31 that enables a focusing servo operation of a lens holder (not shown) including the OBL 4 to be executed based on a focusing error signal generated by the front end processing unit 6. . More specifically, in the optical disc apparatus 1, the focusing error signal generated by the front end processing unit 6 based on the signal detected by the PDIC 5 is input and the direction is orthogonal to the surface Mf of the optical disc M. A focusing servo circuit 31 that generates a control signal for displacing the OBL 4 mounted on the OPU 2 substantially along the optical axis direction Df of the OBL 4. The focusing error signal output from the front end processing unit 6 after being generated by the front end processing unit 6 is input to the focusing servo circuit 31. The focusing servo circuit 31 is configured using an equalizer. The focusing servo circuit 31 is configured as a digital equalizer that can handle digital signals. 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 optical disc apparatus 1 also includes a tracking servo circuit 32 that enables a tracking servo operation of a lens holder (not shown) including the OBL 4 to be executed based on the tracking error signal generated by the front end processing unit 6. . More specifically, the optical disc apparatus 1 receives the tracking error signal generated by the front-end processing unit 6 based on the signal detected by the PDIC 5 and supplies it to the OPU 2 substantially along the radial direction Dt of the optical disc M. A tracking servo circuit 32 that generates a control signal for displacing the equipped OBL 4 is provided. After being generated by the front end processing unit 6, the tracking error signal output from the front end processing unit 6 is input to the tracking servo circuit 32. The tracking servo circuit 32 is configured using an equalizer. The tracking servo circuit 32 is configured as a digital equalizer that can handle digital signals.

  Further, the optical disc apparatus 1 receives, for example, a focusing control signal FDO output from a focusing servo circuit 31, and extracts a signal corresponding to the rotation period Cf (FIG. 3) of the optical disc M based on the focusing control signal FDO. A focusing tilt bandpass filter circuit 41 (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 surface shake occurs in the optical disc M (FIG. 2) during disk reproduction or disk recording, the surface shake component becomes an FDO signal (FIG. 3). A focusing servo operation is executed by supplying an FDO signal.

In addition, the optical disc apparatus 1 (FIG. 1) receives, for example, a tracking control signal TDO output from the tracking servo circuit 32, and corresponds to the rotation cycle Ct (FIG. 5) of the optical disc M based on the tracking control signal TDO. A tracking tilt bandpass filter circuit 42 (FIG. 1) for extracting a signal is provided. TDO in this specification is “tracki”
It is an abbreviation for “ng drive out”. If an eccentricity occurs in the optical disk M (FIG. 4) during disk reproduction or recording, the eccentric component becomes a TDO signal (FIG. 5). The tracking servo operation is executed by passing the TDO signal.

  Further, the optical disc apparatus 1 is configured such that when the angular deviation of the OBL 4 of the OPU 2 is about to occur with respect to the signal layer Ms of the optical disc M, the angular deviation of the OBL 4 is based on the jitter detected by the jitter measuring circuit 9. A focusing tilt signal adjusting circuit 51 for adjusting the tilt of the lens. The focusing tilt signal adjustment circuit 51 can adjust the level of the signal extracted by the focusing tilt bandpass filter circuit 41. For example, an amplifier is used as the focusing tilt signal adjustment circuit 51. Amplifier is an abbreviation for amplifier and means an amplifier.

  Further, the optical disc apparatus 1 is configured such that when the angular deviation of the OBL 4 of the OPU 2 is about to occur with respect to the signal layer Ms of the optical disc M, the angular deviation of the OBL 4 is based on the jitter detected by the jitter measuring circuit 9. A tracking tilt signal adjustment circuit 52 is provided for adjusting the tilt. The tracking tilt signal adjustment circuit 52 can adjust the level of the signal extracted by the tracking tilt bandpass filter circuit 42. For example, an amplifier is used as the tracking tilt signal adjustment circuit 52.

  The optical disc apparatus 1 further includes an addition circuit 53 that adds the tilt value setting adjustment signal output from the tilt value adjustment circuit 23 to the tilt adjustment signals output from the tilt signal adjustment circuits 51 and 52. More specifically, the optical disc apparatus 1 includes a focusing tilt adjustment signal output from the focusing tilt signal adjustment circuit 51, a tracking tilt adjustment signal output from the tracking tilt signal adjustment circuit 52, and a tilt value adjustment circuit 23. An adding circuit 53 for adding the output tilt value setting adjustment signal is provided. A focusing tilt adjustment signal is output from the focusing tilt signal adjustment circuit 51. A tracking tilt adjustment signal is output from the tracking tilt signal adjustment circuit 52. Further, a tilt value setting adjustment signal set to an optimum tilt value is output from the tilt value adjustment circuit 23. These signals are combined by the adder circuit 53.

  The optical disc apparatus 1 further includes a focusing coil drive circuit 61 that receives the focusing control signal output from the focusing servo circuit 31 and supplies a driving signal to the focusing coil 71 provided in the OPU 2. The focusing servo circuit 31 outputs a focusing control signal for reducing the level of the focusing error signal to the focusing coil drive circuit 61 based on the input focusing error signal. The focusing control signal output from the focusing servo circuit 31 is input to the focusing coil drive circuit 61. The focusing coil drive circuit 61 supplies a focusing coil drive signal to the focusing coil 71. When the focal point of the laser beam L focused by the OBL4 is shifted along the focusing direction Df of the OBL4 with respect to the pit Mt of the optical disk M, a focusing coil drive is performed to adjust the OBL4 of the OPU2. A focusing drive signal is sent from the circuit 61 to the focusing coil 71 of the OPU 2. The drive circuit is called a driver or the like.

The optical disc apparatus 1 further includes a tracking coil drive circuit 62 that receives the tracking control signal output from the tracking servo circuit 32 and supplies a drive signal to the tracking coil 72 provided in the OPU 2. The tracking servo circuit 32 outputs a tracking control signal for reducing the level of the tracking error signal to the tracking coil drive circuit 62 based on the input tracking error signal. The tracking control signal output from the tracking servo circuit 32 is input to the tracking coil drive circuit 62. The tracking coil drive circuit 62 supplies a tracking coil drive signal to the tracking coil 72. When the focal point of the laser beam L focused by the OBL 4 is shifted with respect to the pit Mt of the optical disc M along the tracking direction Df of the OBL 4, a tracking coil drive is used to adjust the tracking of the OBL 4 of the OPU 2. A tracking drive signal is sent from the circuit 62 to the tracking coil 72 of the OPU 2.

  The optical disc apparatus 1 further includes a tilt coil drive circuit 63 to which the addition signal output from the addition circuit 53 is input. More specifically, the optical disc apparatus 1 includes a tilt coil drive circuit 63 that receives the tilt control signal output from the adder circuit 53 and supplies a drive signal to the tilt coil 73 provided in the OPU 2. In order to adjust the tilt of the OBL 4 of the OPU 2, a drive signal sent to the tilt coil 73 of the OPU 2 is generated by the tilt coil drive circuit 63 based on the addition signal generated by the adder circuit 53. The tilt coil drive circuit 63 supplies a tilt coil drive signal to the tilt coil 73. When the focus of the laser beam L focused by the OBL 4 is shifted with respect to the pit Mt of the optical disc M, the tilt coil drive circuit 63 changes the tilt to the tilt coil 73 of the OPU 2 in order to adjust the tilt of the OBL 4 of the OPU 2. A tilt drive signal is sent.

  The optical disc apparatus 1 shown in FIG. 1 includes the OPU 2, the optical output signal processing circuit 6, the signal processing circuit, the digital signal processing circuit 8, the jitter value detection circuit 9, and the system control circuit 10. The first memory circuit 11, the second memory circuit 12, the tilt value setting circuit 23, the focusing servo circuit 31, the tracking servo circuit 32, the focusing tilt bandpass filter circuit 41, and the The tracking tilt bandpass filter circuit 42, the focusing tilt signal adjustment circuit 51, the tracking tilt signal adjustment circuit 52, the addition circuit 53, the focusing coil drive circuit 61, the tracking coil drive circuit 62, and the above And a tilt coil drive circuit 63. That. The tilt adjustment circuit of the optical disc apparatus 1 is configured in this way.

  The optical disc apparatus 1 includes a digital signal processing apparatus including a digital signal processing circuit 8, for example, a so-called digital signal processor. The digital signal processor means, for example, a microprocessor mainly specialized in digital signal processing. The digital signal processor is abbreviated as “DSP”. A chip including a digital signal processing circuit 8 constituting the DSP is provided. By using the DSP including the digital signal processing circuit 8, for example, high-speed arithmetic processing in the CPU 10 or the like can be executed. By using the DSP, when signal processing is performed, for example, the SN (signal / noise) ratio is set to about 90 dB (decibel) or more, and the influence of noise is easily avoided, and the ambient temperature depends on the ambient temperature. The influence is also easily suppressed. For this reason, high-precision arithmetic processing and the like are performed at high speed by using the DSP.

  By configuring the optical disk apparatus 1 shown in FIG. 1, the optical disk apparatus 1 capable of setting an optimum tilt value is configured. An optimal tilt value is set in the optical disc apparatus 1 based on the jitter value detected based on the signal read from the optical disc M and the tilt value based on the detected jitter value.

  Next, a tilt value setting method of the optical disc apparatus 1 will be described. In conjunction with the flowchart shown in FIG. 6, a tilt value setting method of the optical disc apparatus 1 will be described with reference to the drawings.

The tilt adjustment method of the optical disc apparatus 1 based on the jitter value is performed as follows. At the time of reproduction / recording of the optical disc M (FIG. 1), servo adjustment such as data reading is completed. In this case, for example, the focus offset adjustment may be already performed. Further, the focus offset adjustment may not be performed yet. Further, for example, the track offset adjustment may be already performed. Moreover, it may be when the offset adjustment of the track has not been performed yet. When the tilt adjustment method of the optical disc apparatus 1 is performed, for example, the tilt adjustment method of the optical disc apparatus 1 including mechanical tilt adjustment is performed.

  Using the optical disc apparatus 1, tilt adjustment of the OBL 4 with respect to the signal surface portion Ms of the optical disc M is performed. Using the optical disc apparatus 1, the tilt value setting method in the optical disc apparatus 1 is performed.

  For example, when the optical disk device 1 is powered on, preparation for executing the tilt value setting method of the optical disk device 1 is started. When the optical disk device 1 is turned on and the optical disk device 1 is turned on, data such as various information is sent from the memory circuit 11 such as the ROM 11 to the system control circuit 10. At this time, for example, various data such as a predetermined jitter value jitter (if) and determination value jitter (is) are sent to the system control circuit 10 and set in the system control circuit 10 (FIG. 6: S1).

  The tilt value setting method of the optical disc apparatus 1 (FIG. 1) uses the optical disc apparatus 1 having the OPU 2 having the OBL 4 to detect the jitter value of the signal read from the optical disc M, and the detected jitter value. When the OBL 4 is focused on the signal surface portion Ms of the optical disc M, the tilt value used for correcting the angular deviation of the OBL 4 with respect to the signal surface portion Ms of the optical disc M is adjusted to adjust the OBL 4 with respect to the optical disc M. This is a tilt value setting method of the optical disc apparatus 1 that performs tilt adjustment. The following tilt value setting process is performed.

  By mounting the optical disc M on the optical disc apparatus 1, an operation for causing the optical disc apparatus 1 to set an appropriate tilt value is substantially started. First, using the optical disk device 1, a tilt voltage is applied to a tilt coil (TILTCOIL) 73, and jitter is measured. When the optical disc apparatus 1 is to perform a tilt value setting method, first, jitter is detected / measured with a tilt value ± 0 (FIG. 6: S2). At this time, for example, as shown in FIG. 10 or FIG. 11, the jitter value jitter (io) at the tilt value ± 0 is set to a small value equal to or less than the specified value jitter (if), and the optical disc M has good jitter characteristics (FIG. 1). If it is determined by the program in the CPU 10 (FIG. 1) (S3: NO), the tilt value is set to 0 (FIG. 6: S8), and the tilt adjustment is completed.

  This optical disc apparatus 1 (FIG. 1) has different tilts depending on the optical disc M having good jitter characteristics and the optical disc (M) that is estimated / determined that the jitter characteristics are not good and each jitter value needs to be detected / inspected. Set the value.

When performing the tilt value setting method in the optical disc apparatus 1 using the optical disc apparatus 1, the jitter values are detected / measured as necessary, for example, as shown in FIGS. More specifically, the jitter value jitter (io) at the tilt value ± 0 is set to a value larger than the specified value jitter (if), and it is estimated / determined that the jitter characteristic is not good by the program in the CPU 10 (FIG. 1). The following measurement is performed on the optical disc (M) determined to require detection / investigation of each jitter value. First, when a jitter value is detected by reading a signal from the optical disc (M), the tilt value within a predetermined range is changed. More specifically, when a jitter value is detected by reading a signal from the optical disk (M), the tilt value reference value 0 (FIGS. 7, 8, and 9) is included and the tilt value reference value 0 is the center. The tilt value is changed stepwise within the predetermined range of values (FIG. 6: S4). Each time the tilt value is changed in stages, the jitter value is detected.

  The operation for setting the tilt value is performed by the tilt value setting circuit 23 in a state where the reproduction operation of the signal recorded on the optical disc (M) (FIG. 1) is performed. In the tilt value setting circuit 23, the value of the tilt value set with respect to the reference value 0 (FIGS. 7, 8, and 9) is changed in steps of 2% from −8% to + 8%. At the same time, the jitter value of the reproduction signal is detected by the jitter measuring circuit 9 corresponding to each tilt value, whereby the tilt value is set.

  More specifically, the signal recorded on the optical disc (M) is reproduced with the tilt value set by the tilt value setting circuit 23 with the tilt value set to a value that is approximately -8% lower than the reference value 0. Is detected by the jitter measuring circuit 9. The jitter value thus detected is stored in the memory circuit 12 such as the RAM 12 together with the tilt value.

  The tilt value is changed in steps of 2% from −8% to + 8% with respect to the reference value 0, and the jitter value corresponding to each tilt value is detected, and the jitter value is stored in the memory circuit 12 together with the tilt value. The operation is repeated.

  For an optical disc (M) in which an operation for setting a tilt value is started in the optical disc apparatus 1 and it is determined that each jitter value needs to be detected / inspected during the tilt adjustment method of the optical disc apparatus 1, first. Every time the tilt value is changed within a predetermined range, an operation for detecting the jitter value is performed (FIG. 6: S4). The predetermined range is, for example, a tilt value between −10% and + 10% set in the tilt value setting circuit 23 with respect to the reference value when the tilt value 0 is determined as the reference value (FIG. 7). , FIG. 8, FIG. 9). For example, when the tilt value 0 is set as a reference value, a preferable range of the tilt value is a range between −8% and + 8% set in the tilt value setting circuit 23 with respect to the reference value.

  For example, if the tilt value is set smaller than −10%, the normal tilt function may not work. For example, when the tilt value is set larger than + 10%, the normal tilt function may not work. For this reason, a tilt value between −10% and + 10% around the reference value 0 of the tilt value is preferably set in the tilt value setting circuit 23. Preferably, a tilt value between −8% and + 8% around the reference value 0 of the tilt value is set in the tilt value setting circuit 23 so that a normal tilt function works.

  For example, the jitter value jitter (io) in the reference value 0 (FIG. 7, FIG. 8, FIG. 9) of the tilt value is set to a value larger than the specified value jitter (if), and it is estimated / determined that the jitter value is not good. For the optical disc (M) (FIG. 1) that needs to detect / inspect the jitter value, the following steps are performed based on the control of the program in the CPU 10. The following steps are performed by the CPU 10 and the second memory circuit 12.

  First, an initial value is set by a program in the CPU 10, and i = -4 is set. Further, for example, a value of “TILT = 2% × i” is set (SET). The OPU 2 measures the jitter value, and the result is stored in the second memory circuit 12 as “jitter (i)”.

  “I” is incremented by a program in the CPU 10. “Increment” means that a numerical value is increased by a predetermined size when repetitive processing or the like is performed by programming. In addition, a value of “TILT = 2% × i” is set.

When “i <5”, the jitter is again measured by the OPU 2 and the result is stored in the second memory circuit 12 as “jitter (i)”. When “i ≧ 5”, the minimum value is obtained from “jitter (i)”, and “i” at that time is set to “imin”. When “i ≧ 5”, the maximum value is obtained from “jitter (i)”, and “i” at that time is set to “imax”.

  Next, an optimum tilt value is set based on the difference value jitter (id) between the maximum jitter value jitter (imax) and the minimum jitter value jitter (imin) in each detected jitter value.

  When each jitter value is detected by changing the tilt value within a predetermined range, the maximum jitter value jitter (imax) and the minimum jitter value jitter (imin) are selected from the detected jitter values. (FIG. 6: S5).

  When the selection setting operation in step S5 is performed, [jitter (imax) −jitter (imin)> jitter (is)] is set (S6: YES), or [jitter (imax) −jitter (imin) > Jitter (is)] is determined (S6: NO). If it is determined in step S6 that [jitter (imax) −jitter (imin)> jitter (is)] (S6: YES), the tilt value corresponding to the minimum jitter value jitter (imin) is set to the optimum tilt. Set as a value (S7). Alternatively, if it is determined in step S6 that [jitter (imax) −jitter (imin)> jitter (is)] is not satisfied (S6: NO), the reference value 0 of the tilt value is set as the optimum tilt value ( S8).

  By performing the tilt value setting method of the optical disc apparatus 1 in this way, an optimum tilt value is set for the optical disc apparatus 1. If necessary, the jitter value is detected every time the tilt value is changed stepwise within a predetermined range of values including the reference value 0 of the tilt value and centering on the reference value 0 of the tilt value. Since the optimum tilt value is set based on the difference value jitter (id) between the maximum jitter value jitter (imax) and the minimum jitter value jitter (imin) in each jitter value, the optical disc apparatus 1 has an optimum tilt value. Is set. Since an optimum tilt value is set for the optical disc apparatus 1, the OPU 2 performs a stable tilt operation on the optical disc M. Also, the tilt value setting operation in the optical disc apparatus 1 can be easily performed.

  FIG. 7 shows the jitter value and tilt value when it is determined in CPU 10 (FIG. 1) that [jitter (imax) −jitter (imin)> jitter (is)] (FIG. 6, S6: YES). It is a characteristic view which shows a relationship.

  As shown in FIG. 7, when the difference value jitter (id) between the maximum jitter value jitter (imax) and the minimum jitter value jitter (imin) is larger than a predetermined value jitter (is). The tilt value corresponding to the minimum jitter value jitter (imin) is set as the optimum tilt value.

  For example, the minimum jitter value jitter (imin) is smaller than the jitter value jitter (if) which is smaller than the maximum jitter value jitter (imax), for example, by a determination value jitter (is). In such a case, an operation for causing the tilt value setting circuit 23 to set a tilt value corresponding to the minimum jitter value jitter (imin), that is, a tilt value larger by + 6% than the reference value 0, as the optimum tilt value is an optical disc. Performed by the apparatus 1.

In the program in the CPU 10 (FIG. 1), the following setting is performed based on the value of “jitter (imax) −jitter (imin)”. “Jitter (imax) −ji
If the value of “tter (imin)” exceeds the fixed value jitter (is), for example, “2% × imin” is set in “TILT”. This completes the tilt adjustment.

  When the tilt value setting operation is performed in this way, a tilt value larger by + 6% than the reference tilt value 0 is set in the tilt value setting circuit 23, and the tilt value is set by the tilt value setting circuit 23 around the set tilt value. Operation is performed.

  By performing the tilt value setting method of the optical disc apparatus 1 in this way, the OPU 2 constituting the optical disc apparatus 1 performs a stable tilt operation on the optical disc (M). The optical disc (M) in which the difference value jitter (id) between the maximum jitter value jitter (imax) and the minimum jitter value jitter (imin) is larger than a predetermined value jitter (is) is jitter. The optical disk (M) has poor characteristics. When a signal is read from the optical disc (M) having poor jitter characteristics, the tilt value corresponding to the minimum jitter value jitter (imin) is set as the optimum tilt value, so that a stable tilt operation is executed in the OPU 2.

  If it is determined in step S6 shown in FIG. 6 that [jitter (imax) −jitter (imin)> jitter (is)] is not satisfied (S6: NO), the reference tilt value 0 is set as the optimum tilt value. (S8).

  FIG. 8 shows a jitter value and a tilt value when it is determined in CPU 10 (FIG. 1) that [jitter (imax) −jitter (imin)> jitter (is)] is not satisfied (FIG. 6, S6: NO). It is a characteristic view which shows the relationship.

  As shown in FIG. 8, when the difference value jitter (id) between the maximum jitter value jitter (imax) and the minimum jitter value jitter (imin) is set to a small value equal to or smaller than a predetermined value jitter (is). The reference value 0 of the tilt value is set as the optimum tilt value. When the maximum value-minimum value (MAX-MIN) in each jitter value is not more than a certain value, the tilt value is set to ± 0. For example, the jitter value of the waveform shown in FIG. 8 is detected, the jitter value jitter (io) at the reference value 0 of the tilt value is set to a value larger than the predetermined jitter value jitter (if), and the maximum jitter value jitter ( The tilt value is set to ± 0 when the difference value jitter (id) between the maximum jitter value jitter (imin) and the minimum jitter value jitter (imin) is set to a value smaller than a predetermined value jitter (is). Alternatively, for example, the jitter values of the waveform shown in FIG. 8 are detected, and each jitter value is set to a value that is larger than a predetermined jitter value jitter (if), and the maximum jitter value jitter (imax) and the minimum jitter value jitter. The tilt value is set to ± 0 when the difference value jitter (id) from (imin) is a small value equal to or less than a predetermined value jitter (is).

  For example, the minimum jitter value jitter (imin) is larger than the jitter value jitter (if) which is smaller than the maximum jitter value jitter (imax), for example, by a determination value jitter (is). In such a case, since the change of the jitter value is small, the operation of setting the reference tilt value as the optimum tilt value in the tilt value setting circuit 23 is performed in the optical disc apparatus 1.

  In the program in the CPU 10 (FIG. 1), the following setting is performed based on the value of “jitter (imax) −jitter (imin)”. When the value of “jitter (imax) −jitter (imin)” is equal to or less than a predetermined value jitter (is), “TILT” is set to 0. This completes the tilt adjustment.

  When the tilt value setting operation is performed in this manner, the tilt operation by the tilt value setting circuit 23 is performed around the reference tilt value 0. Since tilt setting / operation centering on the reference tilt value 0 is performed, tilt control in the OPU 2 can be stably performed.

  By performing the tilt value setting method of the optical disc apparatus 1 in this way, the OPU 2 constituting the optical disc apparatus 1 performs a stable tilt operation on the optical disc M. The optical disc M in which the difference value jitter (id) between the maximum jitter value jitter (imax) and the minimum jitter value jitter (imin) is smaller than a predetermined value jitter (is) is a jitter characteristic. The optical disk M is relatively good. When a signal is read from the optical disc M having relatively good jitter characteristics, the optical disc apparatus 1 is set with the reference value 0 of the tilt value as an optimum tilt value, so that the tilt operation of the OPU 2 is stable and stable. Are executed in OPU2. In addition, the tilt value can be easily set in the optical disc apparatus 1.

  As shown in FIG. 9, when the difference value jitter (id) between the maximum jitter value jitter (imax) and the minimum jitter value jitter (imin) is set to a small value equal to or smaller than a predetermined value jitter (is). The reference value 0 of the tilt value is set as the optimum tilt value. When the maximum value-minimum value (MAX-MIN) in each jitter value is not more than a certain value, the tilt value is set to ± 0. For example, the jitter value of the waveform shown in FIG. 9 is detected, the jitter value jitter (io) at the reference value 0 of the tilt value is set to a value larger than the predetermined jitter value jitter (if), and the maximum jitter value jitter ( The tilt value is set to ± 0 when the difference value jitter (id) between the maximum jitter value jitter (imin) and the minimum jitter value jitter (imin) is set to a value smaller than a predetermined value jitter (is). In such a case, since the change of the jitter value is small, the operation of setting the reference tilt value as the optimum tilt value in the tilt value setting circuit 23 is performed in the optical disc apparatus 1.

  In the program in the CPU 10 (FIG. 1), the following setting is performed based on the value of “jitter (imax) −jitter (imin)”. When the value of “jitter (imax) −jitter (imin)” is equal to or less than a predetermined value jitter (is), “TILT” is set to 0. This completes the tilt adjustment.

  When the tilt value setting operation is performed in this manner, the tilt operation by the tilt value setting circuit 23 is performed around the reference tilt value 0. Since tilt setting / operation centering on the reference tilt value 0 is performed, tilt control in the OPU 2 can be stably performed.

  By performing the tilt value setting method of the optical disc apparatus 1 in this way, the OPU 2 constituting the optical disc apparatus 1 performs a stable tilt operation on the optical disc M. The optical disc M in which the difference value jitter (id) between the maximum jitter value jitter (imax) and the minimum jitter value jitter (imin) is smaller than a predetermined value jitter (is) is a jitter characteristic. The optical disk M is relatively good. When a signal is read from the optical disc M having relatively good jitter characteristics, the optical disc apparatus 1 is set with the reference value 0 of the tilt value as an optimum tilt value, so that the tilt operation of the OPU 2 is stable and stable. Are executed in OPU2. In addition, the tilt value can be easily set in the optical disc apparatus 1.

As described above, when the optical disc (M) (FIG. 1) is tilt-adjusted by the OBL 4 and the optical disc apparatus 1 is set with an optimum tilt value, first, the reference value 0 of the tilt value (FIG. 7, FIG. 8, the jitter value is detected based on FIG. 9, and the jitter value jitter (io) based on the detected reference value 0 of the tilt value is larger than a predetermined jitter value jitter (if). The predetermined range including the reference value 0 of the tilt value (e.g., -8%
Each jitter value detection step of detecting each jitter value is executed every time the tilt value is changed stepwise within the numerical value of .about. + 8% /-10% to + 10%).

  Thus, the optimum tilt value is set in the optical disc apparatus 1 by performing the tilt value setting method of the optical disc apparatus 1 (FIG. 1). When the optical disc (M) is tilt-adjusted by OBL4 and the optical disc apparatus 1 is set with the optimum tilt value, first, the jitter value jitter (io) based on the reference value 0 of the tilt value is detected ( FIG. 6: S2). As shown in FIGS. 7, 8, and 9, the optical disc (M) in which the jitter value jitter (io) based on the reference value 0 of the tilt value is larger than a predetermined jitter value jitter (if). (FIG. 1) is an optical disc (M) that needs to detect / inspect each jitter value corresponding to each tilt value. As shown in FIG. 6, when the jitter value jitter (io) based on the detected reference value 0 of the tilt value is larger than a predetermined jitter value jitter (if) (S3: YES). Next, each jitter value is detected each time the tilt value is changed stepwise within a predetermined range (eg, -8% to +8% /-10% to + 10%) including the reference value 0 of the tilt value. (FIG. 6: S4), and an optimum tilt value is set based on the difference value jitter (id) between the maximum jitter value jitter (imax) and the minimum jitter value jitter (imin) in each detected jitter value. Each jitter value detection / comparison determination / optimum value setting step is executed (FIG. 6: S4, S5, S6, S7 / S8).

  As shown in FIG. 10 and FIG. 11, the jitter value is detected every time the tilt value is changed stepwise within a predetermined range of values including the reference value 0 of the tilt value and centering on the reference value 0 of the tilt value. Before the jitter value is detected, the jitter value is detected based on the reference value 0 of the tilt value, and the jitter value jitter (io) based on the detected reference value 0 of the tilt value is a predetermined jitter value jitter (jitter ( if) The reference value 0 of the tilt value is set as the optimum tilt value when the value is smaller than the following value.

  More specifically, when the tilt adjustment of the OBL 4 is performed on the optical disc M (FIG. 1) and the optimum tilt value is set in the optical disc apparatus 1, first, based on the reference value 0 (FIG. 10) of the tilt value. When the jitter value is detected and the jitter value jitter (io) based on the reference value 0 of the detected tilt value is set to a smaller value than a predetermined jitter value jitter (if), the tilt value Each time the tilt value is changed stepwise within a predetermined range of values including the reference value 0, each jitter value detection step is omitted without detecting each jitter value, and the jitter value based on the reference value 0 of the tilt value Jitter (io) detection process and comparison determination between a predetermined jitter value jitter (if) determined in advance and a jitter value jitter (io) based on a reference value 0 of the tilt value The extent immediately after, to set the reference value 0 of the tilt values as an optimal tilt value.

  When the tilt value is ± 0, the optimum tilt value is set to ± 0 when the jitter value jitter (io) is set to a small value equal to or smaller than a predetermined jitter value jitter (if). When the optical disc M having good jitter characteristics is used, priority is given to the stability of the tilt operation.

By performing the tilt value setting method of the optical disc apparatus 1 (FIG. 1) as described above, when the optical disc M having good jitter characteristics is used, the tilt value is set quickly and the optical disc apparatus 1 is configured. The OPU 2 to perform a stable tilt operation on the optical disc M. When the optical disc M is tilt-adjusted by OBL 4 and the optical disc apparatus 1 is set with the optimum tilt value, first, the jitter value jitter (io) based on the reference value 0 of the tilt value is detected (FIG. 6). : S2). As shown in FIG. 10, the optical disc M (FIG. 1) in which the jitter value jitter (io) based on the reference value 0 of the tilt value is smaller than a predetermined jitter value jitter (if) is a jitter characteristic. The optical disc M is good.

  When a signal is read from the optical disc M having good jitter characteristics, each jitter value is detected without detecting each jitter value every time the tilt value is changed stepwise within a predetermined range of values including the reference value 0 of the tilt value. / Comparison determination step (FIG. 6: S4, S5, S6) is omitted, jitter value jitter (io) detection step based on tilt value reference value 0 (FIG. 6: S2), and predetermined predetermined Immediately after the comparison judgment step (FIG. 6: S3) between the jitter value jitter (if) of the jitter and the jitter value jitter (io) based on the reference value 0 of the tilt value, the optical disc with the reference value 0 of the tilt value as the optimum tilt value Since the apparatus 1 is set (FIG. 6: S8), the time for setting the tilt value in the optical disc apparatus 1 is shortened. In addition, when a signal is read from the optical disc M having good jitter characteristics, the optical disc apparatus 1 is set with the reference value 0 of the tilt value as the optimum tilt value, so that the tilt operation of the OPU 2 can be performed stably without any trouble. Are executed in OPU2.

  Further, when the optical disk M (FIG. 1) is tilt-adjusted by OBL 4 and the optical disk apparatus 1 is set with the optimum tilt value, first, the jitter value is based on the reference value 0 (FIG. 11) of the tilt value. When the jitter value jitter (io) based on the detected tilt value reference value 0 is set to a smaller value than a predetermined jitter value jitter (if), the reference value of the tilt value is detected. Each time the tilt value is changed stepwise within a numerical value in a predetermined range including 0, each jitter value detection step is omitted without detecting each jitter value, and a jitter value jitter (based on the tilt value reference value 0) Immediately after the detection step of io) and the comparison determination step of a predetermined jitter value jitter (if) determined in advance and a jitter value jitter (io) based on the reference value 0 of the tilt value , To set the reference value 0 of the tilt values as an optimal tilt value.

  When the tilt value is ± 0, the optimum tilt value is set to ± 0 when the jitter value jitter (io) is set to a small value equal to or smaller than a predetermined jitter value jitter (if). When the optical disc M having good jitter characteristics is used, priority is given to the stability of the tilt operation.

  By performing the tilt value setting method of the optical disc apparatus 1 (FIG. 1) as described above, when the optical disc M having good jitter characteristics is used, the tilt value is set quickly and the optical disc apparatus 1 is configured. The OPU 2 to perform a stable tilt operation on the optical disc M. When the optical disc M is tilt-adjusted by OBL 4 and the optical disc apparatus 1 is set with the optimum tilt value, first, the jitter value jitter (io) based on the reference value 0 of the tilt value is detected (FIG. 6). : S2). As shown in FIG. 11, the optical disc M (FIG. 1) in which the jitter value jitter (io) based on the reference value 0 of the tilt value is smaller than a predetermined jitter value jitter (if) is a jitter characteristic. The optical disc M is good. Further, for example, as shown in FIG. 11, all the jitter values between the maximum jitter value jitter (imax) and the minimum jitter value jitter (imin) are smaller than a predetermined jitter value jitter (if) that is set in advance. The optical disk M (FIG. 1) having the value is an optical disk M having good jitter characteristics.

When a signal is read from the optical disc M having good jitter characteristics, each jitter value is detected without detecting each jitter value every time the tilt value is changed stepwise within a predetermined range of values including the reference value 0 of the tilt value. / Comparison determination step (FIG. 6: S4, S5, S6) is omitted, jitter value jitter (io) detection step based on tilt value reference value 0 (FIG. 6: S2), and predetermined predetermined Immediately after the comparison judgment step (FIG. 6: S3) between the jitter value jitter (if) of the jitter and the jitter value jitter (io) based on the reference value 0 of the tilt value, the optical disc with the reference value 0 of the tilt value as the optimum tilt value Since the apparatus 1 is set (FIG. 6: S8), the time for setting the tilt value in the optical disc apparatus 1 is shortened. In addition, when a signal is read from the optical disc M having good jitter characteristics, the optical disc apparatus 1 is set with the reference value 0 of the tilt value as the optimum tilt value, so that the tilt operation of the OPU 2 can be performed stably without any trouble. Are executed in OPU2.

  Since the tilt value ± 0 is first measured and set, the measurement time for detecting the jitter value can be shortened. The tilt adjustment can be executed by the optical disc apparatus 1 provided with the OPU 2 only for the optical disc (M) that is estimated / determined that the jitter value is not good and needs to detect / inspect each jitter value. Since the tilt adjustment is performed only on the optical disc (M) that is estimated / determined that the jitter value is not good and each jitter value needs to be detected / inspected, the initial measurement time of the optical disc M with good jitter characteristics in the OPU 2 is reduced. It can be shortened. Further, since the tilt value is set to ± 0 for the optical disc M having good jitter, stable tilt setting can be executed for the optical disc M having good jitter. When the optical disc apparatus 1 is equipped with an optical disc M in which the jitter value does not substantially change, the tilt value in the tilt value setting circuit 23 is set to ± 0, so that a servo failure does not occur and a stable tilt operation can be executed. Become.

  As described above, the tilt value setting method of the optical disc apparatus 1 detects the jitter value each time the tilt value is changed by the predetermined percentage within the predetermined range centered on the reference value 0 of the tilt value. An optimum tilt value setting operation is performed. Before performing such an operation, a jitter value detection operation is performed in a state where the reference tilt value is set to 0 and the tilt value is set. When the detected jitter value jitter (io) is a small value equal to or smaller than the predetermined value jitter (if), that is, when it is determined that the reproduction characteristic of the optical disc M is good, the reference tilt value 0 is optimized as it is. An operation for setting as a tilt value is performed by the optical disc apparatus 1.

  For example, when the jitter value jitter (io) set to perform the determination operation is detected as a small jitter value equal to or smaller than a predetermined jitter value jitter (if), the optical disk M is determined as a benign disk, and the tilt value is determined. Even if the selection operation is not performed, the reproduction operation is performed without any problem.

  Next, a state when a track jump of the OPU 2 is performed when a tilt value other than the reference value 0 is set will be described.

  First, tilt adjustment of the optical disc apparatus 1 (FIG. 1) is performed. At this time, the tilt value is set to a numerical value other than the reference value 0. Before starting the track jump, the reference value 0 is set as the tilt value. Perform a track jump operation. After the track jump, the tilt value is set to a value other than the original reference value 0.

  More specifically, when the optimum tilt value is set to a value other than the reference value 0 (FIG. 7), the tilt value is set when the OPU 2 performs track jump on the optical disc (M) (FIG. 1). Temporarily set the reference value to 0.

By setting the tilt value in this way, the track jump of the OPU 2 with respect to the optical disc (M) can be performed even if a value other than the reference value 0 of the tilt value (eg, + 6%) is set as the optimum tilt value. Done well. When the tilt adjustment of the OPU 2 with respect to the optical disc (M) is performed and the tilt value is set to a value other than the reference value 0 (+ 6%), when the track jump of the OPU 2 with respect to the optical disc (M) is performed, Servo failures were likely to occur in OPU2. However, even when the tilt value is set to a value other than the reference value 0, when the OPU 2 performs a track jump, by temporarily setting the tilt value to the reference value 0, the optical disc (M) The track jump of OPU2 with respect to is likely to be performed normally.

  After the track jump of the OPU 2 with respect to the optical disc (M) is completed, the tilt value is again returned to a value other than the reference value 0 (eg, + 6%) (FIG. 7).

  Thereby, the optimum tilt value for the optical disc apparatus 1 is set again. When the track jump of the OPU 2 is not performed on the optical disk (M), the optical disk apparatus 1 is again set to a numerical value other than the reference value 0 of the tilt value, so that the OBL 2 of the OPU 2 for the optical disk (M) is set. Tilt adjustment is performed satisfactorily. In addition, since the tilt value other than the reference value 0 previously stored in the second memory circuit 12 is again set as the optimum tilt value in the optical disc apparatus 1, the optimum tilt value is quickly reset.

  The optical disc apparatus 1 shown in FIG. 1 can execute the tilt value setting method of the optical disc apparatus 1. Thereby, it is possible to provide the optical disc apparatus 1 capable of setting an optimum tilt value. Servo failure is prevented and a stable tilt operation is executed by the optical disc apparatus 1 including the OPU 2.

  If the tilt adjustment circuit of the optical disc apparatus 1 is configured, even if the optical disc (M) provided in the optical disc apparatus 1 is a surface wobbling disc MA (FIG. 2), the signal layer Ms of the optical disc MA The optical axis La of the laser light L emitted from the LD 3 of the OPU 2 (FIG. 1) is always easy to be orthogonal (FIG. 2).

  When the surface shake operation occurs on the optical disc (M), the focusing adjustment of the OBL 4 and the focusing tilt adjustment of the OBL 4 are performed simultaneously. When the surface shake operation occurs on the optical disc (M), the position of the OBL 4 is automatically adjusted along the vertical direction Da. At the same time, the posture of the OBL 4 is automatically adjusted so that the optical axis La of the laser light transmitted through the OBL 4 is inclined by an angle −Af to + Af. As a result, the optical axis La of the laser beam is always kept orthogonal to the signal layer Ms of the optical disc MA, and the spot Ls formed by the laser beam being narrowed by the OBL 4 is shifted from the pit Mt being followed. This is avoided. Accordingly, it is easy to prevent the occurrence of a focus drop and an error in reading the data on the optical disc MA when the data on the optical disc MA is being read using the OPU 2 (FIG. 1).

  Defocusing means that the focal point of the laser beam L emitted from the LD 3 of the OPU 2 and transmitted through the OBL 4 is shifted with respect to the pit Mt of the optical disc (M) that is being followed, and thus data recorded on the optical disc (M). Means unreadable. Defocusing occurs due to surface deflection of the optical disc (M), eccentricity of the optical disc (M), vibration of the optical disc (M), and impact of the optical disc (M). When the optical disk device 1 is used to reproduce data recorded on the optical disk (M) or when data is recorded on the optical disk (M), the surface vibration of the optical disk (M) in the optical disk device 1 In addition, the eccentricity of the optical disk (M) is supposed to occur constantly. On the other hand, the vibration of the optical disc (M) and the impact of the optical disc (M) are suddenly generated.

  If the tilt adjustment circuit of the optical disc apparatus 1 is configured, even if the optical disc (M) provided in the optical disc apparatus 1 is the eccentric disc MB (FIGS. 4A and 4B), the optical disc MB The optical axis La of the laser light L emitted from the LD 3 of the OPU 2 (FIG. 1) is always easily orthogonal to the signal layer Ms.

When an eccentric operation occurs in the optical disc (M) (FIGS. 4A and 4B), tracking adjustment of OBL4 and tracking tilt adjustment of OBL4 are performed simultaneously. When an eccentric operation occurs in the optical disc (M), the position of the OBL 4 is automatically adjusted along the disc inner / outer direction Db. At the same time, even if the optical axis La of the laser light transmitted through the OBL 4 is inclined by an angle of −At to + At, the posture of the OBL 4 is automatically adjusted. The optical axis La of the laser beam is always kept orthogonal to the signal layer Ms of the optical disc MA, and the spot Ls formed by the laser beam being narrowed by the OBL 4 is shifted from the pit Mt being followed. Is avoided. Therefore, it is easy to prevent the occurrence of a focus drop and an error in reading the data on the optical disc MB when the data on the optical disc MB is being read using the OPU 2 (FIG. 1).

  Further, even when the optical disc (M) provided in the optical disc apparatus 1 is the runout disc MA (FIG. 2), the optical disc (M) provided in the optical disc apparatus 1 is the eccentric disc MB (FIG. 4 (A) ( Even in the case of B)), the track jump of the OPU 2 with respect to the optical disc MA or the optical disc MB is likely to be normally performed.

  The optical disc apparatus 1 including the OPU 2 can be used for a recording / reproducing apparatus that records data / information on an optical disc or reproduces data on the optical disc. Further, the optical disc apparatus 1 provided with the OPU 2 can be used as a reproduction-only apparatus that reproduces data / information of the optical disc.

  The OPU 2 is mounted on the optical disc apparatus 1 that is assembled in, for example, a computer or audio / video equipment. The optical disc apparatus 1 including the OPU 2 is, for example, a notebook personal computer, a laptop personal computer, a desktop personal computer, or a computer such as “CD”, “DVD”, “HD-DVD”, “Blu ray Disc”. Can be installed in an audio / video device or the like (not shown).

  As mentioned above, although embodiment of this invention was described, embodiment mentioned above is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed / improved without departing from the gist thereof, and equivalents thereof are also included.

It is a block diagram which shows one Embodiment of the optical disk apparatus based on this invention. It is explanatory drawing which shows the operation state of the surface runout disk with which the optical disk apparatus was equipped. It is a wave form diagram which shows a rocking | fluctuation period when a surface shake disc is rotated. FIG. 5A shows the operating state of an eccentric disk mounted in the optical disk apparatus, FIG. 5A is an explanatory diagram showing a state in which the objective lens is tilted toward the disk outer periphery side of the eccentric disk, and FIG. It is explanatory drawing which shows the state in which the objective lens was inclined toward the circumferential side. It is a wave form diagram which shows a rocking | fluctuation period when an eccentric disk is rotated. 4 is a flowchart showing an embodiment of a tilt value setting method for an optical disc apparatus according to the present invention. It is a graph which shows the relationship between a tilt value and a jitter value. It is a graph which similarly shows the relationship between a tilt value and a jitter value. It is a graph which similarly shows the relationship between a tilt value and a jitter value. It is a graph which similarly shows the relationship between a tilt value and a jitter value. It is a graph which similarly shows the relationship between a tilt value and a jitter value.

Explanation of symbols

1 Optical disk device (disk device)
2 OPU (Pickup device)
3 LD (light emitting device)
4 OBL (objective lens)
5 PDIC (Photodetector)
6 Front-end processing unit (optical output signal processing circuit)
7 RF signal amplification / processing circuit (signal processing circuit)
8 Digital signal processing circuit 9 Jitter measurement circuit (jitter value detection circuit)
10 CPU (system control circuit)
11 ROM (memory circuit)
12 RAM (memory circuit)
23 Tilt value setting circuit 31 EQ (Focusing servo circuit)
32 EQ (tracking servo circuit)
41 Focusing tilt bandpass filter circuit (bandpass filter circuit)
42 Tracking tilt bandpass filter circuit (bandpass filter circuit)
51 Focusing tilt signal adjustment circuit (tilt signal adjustment circuit)
52 Tracking tilt signal adjustment circuit (tilt signal adjustment circuit)
53 Addition circuit 61 Driver (Focusing coil drive circuit)
62 Driver (Tracking coil drive circuit)
63 Driver (tilt coil drive circuit)
71 Focusing coil 72 Tracking coil 73 Tilt coil Af, At Angle Cf, Ct Rotation period Da Up / down direction of disc (up / down 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 Focusing direction (direction)
Dt Tracking direction (direction)
FDO focusing control signal L beam (light)
La Optical axis Ls Spot (focus)
M optical disc MA surface runout disc (optical disc)
MB Eccentric disc (optical disc)
Mc Inner perimeter Md Outer perimeter Mf Surface (surface)
Ms Signal surface (signal layer)
Mt pit (signal part)
TDO tracking control signal

Claims (10)

A jitter value detection circuit for detecting a jitter value based on a signal read from the optical disc;
The tilt value used to correct the angular deviation of the objective lens with respect to the signal layer of the optical disk is adjusted based on the signal that has passed through the jitter value detection circuit when the objective lens is focused on the optical disk. And a tilt value setting circuit for performing tilt adjustment based on the tilt value;
An optical disc apparatus comprising: Using an optical disk device equipped with an optical pickup device having an objective lens, the jitter value of the signal read from the optical disk is detected,
Based on the jitter value, when the objective lens is focused on the optical disc, the tilt value used to correct the angular deviation of the objective lens with respect to the signal layer of the optical disc is adjusted to A tilt value setting method for an optical disc apparatus for performing tilt adjustment of the objective lens,
If necessary, the jitter value is detected each time the tilt value is changed stepwise within a predetermined range of values including the reference value of the tilt value,
A tilt value setting method for an optical disc apparatus, comprising: setting an optimum tilt value based on a difference value between a maximum jitter value and a minimum jitter value in each detected jitter value. A jitter value detection circuit for detecting a jitter value based on a signal detected by a photodetector provided in the optical pickup device;
Used to correct the angular deviation of the objective lens with respect to the signal layer of the optical disc when the objective lens of the optical pickup device is focused on the optical disc based on the signal that has passed through the jitter value detection circuit. A tilt value setting circuit for adjusting a tilt value and performing a tilt adjustment based on the tilt value;
A tilt value setting method for an optical disk apparatus, wherein the tilt adjustment of the objective lens with respect to the optical disk is performed using an optical disk apparatus comprising:
When reading the signal from the optical disc and detecting the jitter value,
If necessary, the jitter value is detected every time the tilt value is changed stepwise within a predetermined range of values including the reference value of the tilt value,
A tilt value setting method for an optical disc apparatus, comprising: setting an optimum tilt value based on a difference value between a maximum jitter value and a minimum jitter value in each detected jitter value. When the difference value between the maximum jitter value and the minimum jitter value is larger than a predetermined value, the tilt value corresponding to the minimum jitter value is set as the optimum tilt value. 4. The tilt value setting method for an optical disc apparatus according to claim 2 or 3. The reference value of the tilt value is set as the optimum tilt value when a difference value between the maximum jitter value and the minimum jitter value is a small value equal to or smaller than a predetermined value. The tilt value setting method for an optical disc apparatus according to any one of claims 2 to 4. When the tilt adjustment of the objective lens is performed on the optical disc, the jitter value is first detected based on the reference value of the tilt value, and the detected jitter value is set to a predetermined jitter. The jitter value is detected every time the tilt value is changed stepwise within the predetermined range of values including the reference value of the tilt value when the value is larger than the value. 6. A tilt value setting method for an optical disc apparatus according to claim 2. When the tilt adjustment of the objective lens is performed on the optical disc, the jitter value is first detected based on the reference value of the tilt value, and the detected jitter value is set to a predetermined jitter. The tilt value without detecting the jitter value every time the tilt value is changed stepwise within the predetermined range of values including the reference value of the tilt value. 7. The tilt value setting method for an optical disc apparatus according to claim 2, wherein the reference value of the value is set as the optimum tilt value. When the optimum tilt value is set to the numerical value other than the reference value, the tilt value is set to the reference value when the optical pickup device performs a track jump on the optical disc. The tilt value setting method for an optical disc apparatus according to any one of claims 2 to 7. 9. The tilt value setting method for an optical disc apparatus according to claim 8, wherein the tilt value is returned to the numerical value other than the reference value after the track jump of the optical pickup device with respect to the optical disc is completed. The optical disk apparatus according to claim 1, wherein the tilt value setting method for an optical disk apparatus according to any one of claims 2 to 9 is executable.

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