JP2007287221A - Optical disk device, tracking control method, and tracking control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device in which appropriate tracking control can be performed even when a temperature in a device is raised during reproduction of an optical disk, and to provide a tracking control method and a tracking control program. <P>SOLUTION: Deviation of an optical beam from the track is corrected on the basis of a first offset voltage (optional offset voltage) when temperature in the optical disk device (optical disk device 100) becomes a prescribed temperature during reproduction of the optical disk. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus, a tracking control method, and a tracking control program, and more particularly to an optical disc apparatus, a tracking control method, and a tracking control program for reproducing information recorded on an optical disc.

  2. Description of the Related Art Conventionally, an optical disk device that reproduces information recorded on an optical disk is known. In such an optical disc apparatus, it is necessary to prevent so-called tracking servo off-tracking, in which the spot of the light beam emitted from the optical pickup deviates from the center position of the target track. Therefore, a track cross signal (track error signal) is generated from the reflected light of the light beam irradiated on the recording surface of the optical disc from the optical pickup by a push pull method, a DPP (Differential Push Pull) method, etc. Tracking control is performed based on the derived offset voltage.

  As a factor that causes off-track, a temperature rise in the optical disc apparatus can be cited. For example, when the optical disk loaded in the optical disk apparatus is continuously reproduced, the temperature rise in the apparatus may reach about 10 ° C. compared to the ambient temperature outside the apparatus. Such a temperature change in the apparatus affects the current flowing through the laser light source of the optical pickup and the characteristics of the light receiving sensitivity of the light receiving element that receives the reflected light from the recording surface of the optical disk. The characteristics may change. As a result, an error occurs in the generated track cross signal, so that there is a problem that proper tracking control cannot be performed.

Therefore, conventionally, assuming a temporal change in the temperature near the optical pickup due to heat generation in the optical disc apparatus, the tracking offset of the optical pickup is exceeded when a preset time has passed during the reproduction of one optical disc. A technique for correcting the voltage has been proposed (see, for example, Patent Document 1).
JP 2001-118264 A

  However, the technique described in Patent Document 1 merely assumes the temperature in the optical disc apparatus with a temporal change, and therefore does not always perform proper tracking control. For example, when the ambient temperature outside the optical disk device changes during optical disk playback, there may be a difference between the assumed temperature and the actual temperature, so tracking control is performed more than necessary, There is a possibility that tracking control is not performed when necessary.

  An object of the present invention is to provide an optical disc apparatus, a tracking control method, and a tracking control program capable of performing appropriate tracking control even when the temperature in the apparatus rises during reproduction of the optical disc. is there.

In order to solve the above-mentioned problem, the invention described in claim 1
An optical disc apparatus that reads and reproduces information recorded on an optical disc by an optical pickup,
A reflected light detecting means for irradiating a light beam from the optical pickup and detecting reflected light from the optical disc;
Driving means for moving the optical pickup in the radial direction of the optical disc;
When the optical pickup crosses an arbitrary track of the optical disk by the driving means, a track cross signal representing a deviation amount of the light beam with respect to the track based on the reflected light detected by the reflected light detecting means. Track cross signal generating means for generating;
Temperature detecting means for detecting the temperature in the optical disc device;
When reproducing the optical disc, if the temperature detected by the temperature detecting means reaches a predetermined temperature, the driving means is driven to move the optical pickup by a predetermined number of tracks, and the track at the time of the movement is moved. Correction means for correcting the shift amount based on a first offset voltage calculated from a cross signal;
It is characterized by having.

Furthermore, the invention according to claim 2 is the invention according to claim 1,
Temporary storage means for temporarily storing information read by the optical pickup for a predetermined number of tracks;
Reproduction control means for sequentially reproducing the temporarily stored information;
With
The correction means moves the optical pickup within a range of the number of tracks temporarily stored.

Furthermore, the invention according to claim 3 is the invention according to claim 1 or 2,
Storage means for storing offset information in which the radial position of the optical disc is associated with the second offset voltage for correcting the shift amount according to the radial position;
The correction means corrects the shift amount based on a third offset voltage obtained by adding or subtracting the first offset voltage to or from the second offset voltage.

Moreover, in order to solve the said subject, invention of Claim 4 is the following.
A method for tracking control of an optical disc apparatus that reads and reproduces information recorded on an optical disc by an optical pickup,
A reflected light detection step of irradiating a light beam from the optical pickup and detecting reflected light from the optical disc;
A driving step of moving the optical pickup in a radial direction of the optical disc;
When the optical pickup crosses an arbitrary track of the optical disk in the driving step, a track cross signal representing a deviation amount of the light beam with respect to the track is calculated based on the reflected light detected in the reflected light detection step. A track cross signal generation process to be generated; and
A temperature detection step of detecting the temperature in the optical disc device;
When reproducing the optical disc, if the temperature detected by the temperature detection step becomes a predetermined temperature, the optical pickup is moved by a predetermined number of tracks by the driving step, and the track cross signal at the time of this movement is And a correction step of correcting the shift amount based on the calculated first offset voltage.

The invention according to claim 5 is the invention according to claim 4,
A temporary storage step of temporarily storing information read by the optical pickup for a predetermined number of tracks;
A reproduction control step of sequentially reproducing the temporarily stored information;
In the correcting step, the optical pickup is moved within the range of the temporarily stored number of tracks.

Further, the invention according to claim 6 is the invention according to claim 4 or 5,
Storage means for storing offset information in which the radial position of the optical disc is associated with the second offset voltage for correcting the shift amount according to the radial position;
In the correcting step, the shift amount is corrected based on a third offset voltage obtained by adding or subtracting the first offset voltage to or from the second offset voltage.

Moreover, in order to solve the said subject, invention of Claim 7 is the following.
The information recorded on the optical disc is read out by an optical pickup and reproduced by a computer of the optical disc apparatus.
A reflected light detection function for irradiating a light beam from the optical pickup and detecting reflected light from the optical disc;
A drive function for moving the optical pickup in the radial direction of the optical disc;
When the optical pickup crosses an arbitrary track of the optical disk by the driving function, a track cross signal representing a deviation amount of the light beam with respect to the track based on the reflected light detected by the reflected light detection function. A track cross signal generation function to generate,
A temperature detection function for detecting the temperature in the optical disc device;
When the temperature detected by the temperature detection function reaches a predetermined temperature during reproduction of the optical disc, the optical pickup is moved by a predetermined number of tracks by the driving function, and the track cross signal at the time of the movement is And a correction function for correcting the shift amount based on the calculated first offset voltage.

The invention according to claim 8 is the invention according to claim 7,
In the computer,
A temporary storage function for temporarily storing information read by the optical pickup for a predetermined number of tracks;
A playback control function for sequentially playing back the temporarily stored information;
Realized,
The correction function is characterized in that the optical pickup is moved within a range of the number of tracks temporarily stored.

The invention according to claim 9 is the invention according to claim 7 or 8,
Storage means for storing offset information in which the radial position of the optical disc is associated with the second offset voltage for correcting the shift amount according to the radial position;
The correction function corrects the shift amount based on a third offset voltage obtained by adding or subtracting the first offset voltage to or from the second offset voltage.

  According to the first, fourth, and seventh aspects of the present invention, at the time of reproducing the optical disc, the deviation of the light beam from the track based on the first offset voltage when the temperature in the optical disc apparatus reaches a predetermined temperature. Since the amount is corrected, proper tracking control can be performed even when the temperature in the optical disc apparatus rises.

  According to the second, fifth, and eighth aspects of the invention, since the optical pickup is moved within the range of the number of tracks temporarily stored, appropriate tracking control can be performed while preventing interruption of reproduction.

  According to the third, sixth, and ninth aspects of the invention, since the second offset voltage corresponding to the radial position of the optical disk can be corrected by the first offset voltage, more appropriate tracking control is performed. Can do.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

FIG. 1 is a diagram showing a configuration of an optical disc apparatus 100 according to the present invention.
The turntable 1 is a mounting table on which the optical disk 2 is mounted, and is fixed to the spindle motor 3. The spindle motor 3 is driven under the control of the linear velocity control circuit 4 and rotates the turntable 1 to rotate the optical disk 2 placed on the turntable 1.

  Here, the optical disk 2 means a storage medium that uses a laser beam for reproducing (reading) information. For example, CD, DVD, CD-R (RW), DVD ± R (RW), MO (Magneto- Examples include optical disk (PD), phase change rewritable disk (PD), DVD-RAM, HD-DVD (registered trademark), and Blu-ray Disk (registered trademark).

  The optical pickup 5 includes an optical member (not shown) such as a prism and an objective lens for irradiating the recording surface of the optical disc 2 with a laser beam emitted from a laser light source such as a built-in laser diode as a light beam spot. The laser light receiving unit 6 is provided for detecting the reflected light of the light beam applied to. The optical pickup 5 also includes a lens actuator (not shown) that displaces the focal position of the objective lens in the vertical and horizontal directions. The number of built-in laser light sources is not particularly limited, and corresponds to each recording method in the case of an optical disc apparatus 100 (so-called combo drive or multi-drive) that reproduces a plurality of recording method optical discs. A plurality of laser light sources having laser characteristics may be provided.

  The laser light receiving unit 6 includes a light receiving element such as a photodiode, a CCD (Charge Coupled Devices), or a CMOS (Complementary Metal Oxide Semiconductor) image sensor, and generates a photocurrent signal corresponding to the detected light intensity as a data signal generation unit. 7 and the servo signal generator 8.

  The data signal generation unit 7 converts the photocurrent signal output from the laser light receiving unit 6 into a voltage signal, generates a data signal that is a modulation signal of information recorded on the recording surface of the optical disc 2 from the voltage signal, Output to the system control unit 9.

The servo signal generation unit 8 converts the photocurrent signal output from the laser light receiving unit 6 into a voltage signal, and represents the amount of deviation of the light beam emitted from the optical pickup 5 from the voltage signal with respect to the track of the optical disc 2. A track cross signal is generated and output to the system control unit 9.
In addition, the servo signal generation unit 8 generates a focus error signal representing the amount of focus shift on the recording surface of the optical disc 2 of the light beam irradiated from the optical pickup 5 from the voltage signal, and outputs the focus error signal to the system control unit 9. .

  The system control unit 9 includes a calculation circuit such as a CPU (Central Processing Unit) and an ASIC (Application Specific Integrated Circuit), and a storage circuit such as a ROM (Read Only Memory) and a RAM (Random Access Memory). Various processes are executed in cooperation with a predetermined program stored in the circuit, and the operation of each unit constituting the optical disc apparatus 100 is comprehensively controlled.

  Specifically, the system control unit 9 extracts a synchronization signal from the data signal input from the data signal generation unit 7 and outputs it to the linear velocity control circuit 4. The linear velocity control circuit 4 outputs from the system control unit 9. The frequency of the synchronized signal is compared with the frequency of a reference synchronization signal such as an internal clock, and the rotation of the spindle motor 3 is controlled so that the frequencies of both signals coincide.

  The system control unit 9 extracts address data indicating the recording position of the optical disc 2 based on the data signal (information) input from the data signal generation unit 7 and address information described later, and the address data and the search target. The linear velocity control circuit 4, the focus control circuit 10, the tracking control circuit 11, the tilt control circuit 12, and the laser control unit 13 are controlled in accordance with the difference between the optical pickup 5 and the target address (track) position. Control to move.

  Here, the address information is information indicating the recording position of the information recorded on the optical disc. For example, in the case of a CD, time information recorded in a subcode can be used. Can use physical addresses stored in groups.

  Further, the system control unit 9 detects the focal position of the light beam emitted from the optical pickup 5 from the focus error signal input from the servo signal generation unit 8, and focuses the driving voltage corresponding to the focal position. Focus control is performed by applying the voltage from the control circuit 10 to the drive coil of the optical pickup 5. The focus control circuit 10 applies a drive voltage according to an instruction from the system control unit 9 to the drive coil of the optical pickup 5 to displace the objective lens in the optical axis direction of the light beam.

  Further, the system control unit 9 calculates an offset voltage for correcting the shift amount of the light beam emitted from the optical pickup 5 with respect to the track from the track cross signal input from the servo signal generation unit 8, and based on this offset voltage. The tracking control is performed by outputting an instruction signal for correcting the shift amount to the tracking control circuit 11. The tracking control circuit 11 applies an offset voltage according to an instruction from the system control unit 9 to the drive coil of the optical pickup 5 to displace the objective lens in a direction orthogonal to the optical axis of the light beam.

FIG. 2 is a diagram showing an example of a waveform of a track cross signal generated when the light beam of the optical pickup 5 crosses a track of the optical disc 2.
The offset voltage is a voltage corresponding to Vo shown in FIG. 2, and the reference voltage V volt (for example, 0 V) serving as a reference when performing tracking control and the voltage of the center value of the positive and negative peak voltages in the waveform of the track cross signal. Bolt). The system control unit 9 calculates an offset voltage based on the track cross signal input from the servo signal generation unit 8 and outputs an instruction signal for adding or subtracting the correction voltage to the tracking control circuit 11 so that Vo becomes V volts. By performing the output, tracking control for correcting the shift amount of the light beam with respect to the track is performed.

  Further, the system control unit 9 outputs an instruction signal for instructing the optical pickup 5 to move to a target track of the optical disc 2 to the tracking control circuit 11 based on the address data or the like, thereby roughly moving the optical pickup 5. Take control. The tracking control circuit 11 moves the optical pickup 5 in the radial direction of the optical disc 2 by applying a driving voltage according to an instruction from the system control unit 9 to the sled motor 14.

  The system control unit 9 also makes an angle (radial tilt) between the optical axis of the light beam emitted from the optical pickup 5 and the recording surface of the optical disc 2 based on the track cross signal input from the servo signal generation unit 8. And the tilt control of the optical pickup 5 is performed by outputting to the tilt control circuit 12 an instruction signal for instructing that the optical axis of the light beam is always perpendicular to the recording surface of the optical disc 2. The tilt control circuit 12 applies a drive voltage (tilt offset voltage) according to an instruction from the system control unit 9 to the tilt motor 15 to displace the angle of the optical pickup 5 with respect to the recording surface of the optical disc 2.

  In the present embodiment, the angle of the optical pickup 5 itself with respect to the recording surface of the optical disc 2 is displaced. However, the present invention is not limited to this. For example, the angle of the objective lens itself can be changed in the radial tilt and / or tangential tilt direction. Alternatively, a lens actuator that can be displaced is provided in the optical pickup 5, and this lens actuator may be controlled by the tilt control circuit 12.

  Further, the system control unit 9 controls the laser control unit 13 to control the irradiation timing of the laser light emitted from the light source of the optical pickup 5. The laser control unit 13 supplies driving power to the laser light source in accordance with an instruction from the system control unit 9 to control ON / OFF of the laser light emitted from the laser light source. When the optical pickup 5 has a plurality of laser light sources, the system control unit 9 records the optical disc 2 based on the focus S-shaped signal when the objective lens is moved away from the optical disc. And control is performed so that laser light is emitted from a laser light source corresponding to the recording method.

  The buffer memory 16 is composed of a volatile semiconductor memory or the like having a storage capacity capable of temporarily storing a predetermined number of tracks (for example, 10 tracks), and is related to reproduction of the optical disc 2 under the control of the system control unit 9. Data signals are temporarily stored sequentially in a FIFO manner. That is, the system control unit 9 temporarily stores the data signal read from the optical disk by the optical pickup 5 in the buffer memory 16 during the reproduction of the optical disk 2 and reads the data to be continuously reproduced in advance. A so-called prefetching process for temporarily storing the data until the storage capacity becomes full is performed. Then, the system control unit 9 sequentially reads the data signals temporarily stored in the buffer memory 16 and outputs them to the external device via the I / O unit 17 to perform reproduction.

  The I / O unit 17 is an interface such as RS232C, RS422, USB (Universal Serial Bus), ATAPI (ATA Packet Interface), etc., for communicating with an external device. The data signal is output to the control unit 9 and the data signal input from the system control unit 9 is output to an external device.

  The temperature sensor 18 is a temperature sensor such as a platinum resistance thermometer or a thermistor. The temperature sensor 18 detects the temperature in the optical disc apparatus 100 (hereinafter referred to as “in-apparatus temperature”), and sends a temperature signal corresponding to the detected temperature signal to the system controller 9. Output to. Here, the temperature sensor 18 is preferably arranged in the vicinity of the optical pickup 5.

  Based on the temperature signal input from the temperature sensor 18, the system control unit 9 performs the tracking control circuit 11 when the temperature inside the apparatus indicated by the temperature signal becomes a predetermined temperature (hereinafter referred to as trigger temperature). The optical pickup 5 is moved by a predetermined amount in the radial direction of the optical disc by controlling the offset, and an offset voltage (hereinafter referred to as an offset voltage as occasion demands) based on a track cross signal generated by the servo signal generator 8 from the reflected light at the time of movement. ) And tracking control is performed based on the offset amount as needed.

Hereinafter, the operation of the optical disc apparatus 100 will be described with reference to FIGS.
FIG. 3 is a flowchart showing the tracking control operation during reproduction of the optical disc. This process is a process executed by the cooperation of the system control unit 9 and various programs stored in a ROM (not shown).

  First, when it is detected that the optical disk 2 is placed on the turntable 1 (step S11), the tracking control circuit 11 is controlled to move the optical pickup 5 to the inner peripheral side of the optical disk 2, and the optical pickup 5 is The optical disk 2 is moved to the innermost peripheral position (step S12). Here, the innermost peripheral position means the maximum position where the optical pickup 5 can move in the inner peripheral direction. Moreover, the outermost periphery position mentioned later means the maximum position where the optical pick-up 5 can move to an outer periphery direction.

  Next, the laser control unit 13 is controlled to irradiate the recording surface of the optical disc 2 from the optical pickup 5 and to control the linear velocity control circuit 4 to drive the spindle motor 3 (step S13). Focus control is performed based on the focus error signal input from the signal generator 8 (step S14).

  Subsequently, when the tracking control circuit 11 is controlled to move the optical pickup 5 to the outer peripheral side of the optical disc 2 and the optical pickup 5 is moved to the outermost peripheral position of the optical disc 2 (step S15), a servo signal is generated during this movement. Based on the track cross signal input from the unit 8, an offset voltage at each radial position of the optical disc 2 (hereinafter, always referred to as an offset voltage) is calculated (step S16), and the radial position and the radial position are determined according to the radial position. The offset information associated with the regular offset voltage is temporarily stored in a RAM or buffer memory 16 (not shown) (step S17).

FIG. 4 is a diagram showing an example of offset information.
As shown in FIG. 4, in the offset information, a radial position of the optical disc 2 and a constant offset voltage corresponding to the radial position are set in association with each other. In general, the optical disc 2 itself may be inclined due to warpage or the like. For example, warpage occurs in the upper surface (front surface) direction or the lower surface (recording surface) direction of the optical disc 2 from the inner periphery side to the outer periphery side. There is a case. Therefore, tracking control suitable for each radial position can be performed by setting a constant offset voltage according to each radial position.

  In steps S15 and S16, the system controller 9 detects the tilt of the recording surface, and the tilt offset voltage for controlling the optical axis of the light beam to be perpendicular to the detected tilt is described above. The offset voltage is always stored in association with each radial position of the optical disc 2. When reproducing the optical disc 2, the system control unit 9 reads out the constant offset voltage and the tilt offset voltage associated with each radial position of the optical disc 2 from the offset information, and performs tracking control of an instruction signal instructing application of these voltages. By outputting to the circuit 11 and the tilt control circuit 12, tracking control and tilt control are executed.

  Further, the offset information may be stored in a table format in which each radial position is always associated with the offset voltage, or a function formula or the like that can uniquely derive the offset voltage from each radial position uniquely. It is good also as memorizing.

  Returning to FIG. 3, based on the temperature inside the apparatus detected by the temperature sensor 18, a trigger temperature is determined as a trigger when executing the tracking control processing (see FIG. 5) described later, and this trigger temperature is not shown. Are temporarily stored in the RAM or buffer memory 16 (step S18). In the present embodiment, the trigger temperature is determined according to the current temperature inside the optical disc apparatus 100. However, the present invention is not limited to this, and a predetermined trigger temperature may be used. The trigger temperature may be information indicating a specific temperature (for example, 40 ° C. or higher) or information indicating a predetermined temperature interval (for example, every 5 ° C. increase). Also good.

  When the focus control circuit 10, the tracking control circuit 11, and the tilt control circuit 12 are asserted and the focus, tracking, and tilt of the optical pickup 5 are within the predetermined error range of the optical pickup control (step S19), they are recorded on the optical disc 2. Information (data signal) is read, and the read data signal is temporarily stored in the buffer memory 16 and then sequentially output via the I / O unit 17, thereby reproducing the optical disc 2. (Step S20).

  During the regeneration, the temperature signal input from the temperature sensor 18 is monitored, and it is determined whether or not the temperature indicated by the temperature signal has reached the trigger temperature determined in step S18, and it is determined that the temperature has not been reached. If (Step S21; No), the process proceeds to Step S23.

  On the other hand, if it is determined in step S21 that the trigger temperature has been reached (step S21; Yes), the process proceeds to an optional tracking control process in step S22. Hereinafter, the tracking control process at any time in step S22 will be described with reference to FIG.

FIG. 5 is a flowchart showing the operation of the tracking control process as needed.
First, the tracking control circuit 11 is controlled so that the optical pickup 5 moves by a predetermined number of tracks (for example, 3 tracks) within the range of the number of tracks (for example, 10 tracks) temporarily stored in the buffer memory 16; When the optical pickup 5 is moved to the target track (step S221), an offset voltage is calculated from the track cross signal at the time of movement (step S222). It should be noted that in an optical disc that is reproduced from the inner circumference side to the outer circumference side of the optical disc, it is preferable to control the optical disc to move by a predetermined number of tracks to the inner circumference side, and to the target track and / or the target track. In consideration of the access time required for the return path from the vehicle, it is more preferable to control the movement within the range of the number of tracks where reproduction is not interrupted.

  Next, the offset voltage is always corrected by adding or subtracting the calculated offset voltage to the always offset voltage of the offset information stored in the RAM (not shown) (step S223). From step S223, the system control unit 9 performs tracking control based on the corrected constant offset voltage.

  Subsequently, after the track temporarily stored in the buffer memory 16 and the track on which the optical pickup 5 is located are synchronized (step S224), the trigger temperature is set based on the temperature in the apparatus detected by the temperature sensor 18. The corrected trigger temperature is temporarily stored in the RAM or buffer memory 16 (not shown) (step S225), and the process proceeds to step S23.

  Thus, since the optical pickup is moved within the range of the number of tracks temporarily stored in the buffer memory 16, the value of the offset voltage can always be corrected while preventing the reproduction from being interrupted. Thereby, the convenience of the user can be achieved, and more appropriate tracking control can be performed.

  Returning to FIG. 3, in step S <b> 23, it is determined whether or not the reproduction of the optical disk 2 has been completed. If it is determined that reproduction is in progress (step S <b> 23; No), the process returns to step S <b> 20 again. Will continue. If it is determined in step S23 that the reproduction has been completed (step S23; Yes), the spindle motor drive and light beam irradiation are stopped, and various servo systems are negated (step S24). This process ends.

FIG. 6 is a timing chart showing the operation of the tracking control described above.
Here, the horizontal axis represents the reproduction time of the optical disc 2, and the vertical axis represents the temperature in the apparatus detected by the temperature sensor 18.

  First, when the optical disc is played back at the playback time “0” and tracking control is started, the temperature inside the optical disc device 100 rises as the playback time elapses. In this state, when the temperature in the apparatus reaches the trigger temperature “Tr1”, the above-described ad hoc tracking control process (see FIG. 5) is executed by the system control unit 9 (first time) and corrected by the ad hoc tracking control process. Tracking control is always performed based on the offset voltage. Further, when the sensor temperature reaches the trigger temperature “Tr2” corrected by the previous tracking control process, the system control unit 9 executes the tracking control process as described above (second time), and the correction is performed by this tracking control process. Tracking control is performed based on the always offset voltage.

  As described above, during the reproduction of the optical disc 2, the amount of deviation of the light beam from the track is corrected based on the offset voltage when the temperature in the optical disc device 100 reaches a predetermined temperature. Even when the temperature rises, proper tracking control can be performed.

  The detailed configuration and detailed operation of the above embodiment can be changed as appropriate without departing from the spirit of the present invention.

1 is a diagram showing a configuration of an optical disc device 100. FIG. It is the figure which showed an example of the waveform of a track cross signal. 5 is a flowchart showing an operation of tracking control during reproduction of an optical disc. It is the figure which showed an example of offset information. It is the flowchart which showed operation | movement of the tracking control process at any time. It is a timing chart showing operation of tracking control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Optical disk apparatus 1 Turntable 2 Optical disk 3 Spindle motor 4 Linear velocity control circuit 5 Optical pick-up 6 Laser light receiving part 7 Data signal generation part 8 Servo signal generation part 9 System control part 10 Focus control circuit 11 Tracking control circuit 12 Tilt control circuit 13 Laser control unit 14 Thread motor 15 Tilt motor 16 Buffer memory 17 I / O unit 18 Temperature sensor

Claims (9)

An optical disc apparatus that reads and reproduces information recorded on an optical disc by an optical pickup,
A reflected light detecting means for irradiating a light beam from the optical pickup and detecting reflected light from the optical disc;
Driving means for moving the optical pickup in the radial direction of the optical disc;
When the optical pickup crosses an arbitrary track of the optical disk by the driving means, a track cross signal representing a deviation amount of the light beam with respect to the track based on the reflected light detected by the reflected light detecting means. Track cross signal generating means for generating;
Temperature detecting means for detecting the temperature in the optical disc device;
When reproducing the optical disc, if the temperature detected by the temperature detecting means reaches a predetermined temperature, the driving means is driven to move the optical pickup by a predetermined number of tracks, and the track at the time of the movement is moved. Correction means for correcting the shift amount based on a first offset voltage calculated from a cross signal;
An optical disc apparatus comprising: Temporary storage means for temporarily storing information read by the optical pickup for a predetermined number of tracks;
Reproduction control means for sequentially reproducing the temporarily stored information;
With
The optical disk apparatus according to claim 1, wherein the correction unit moves the optical pickup within a range of the number of tracks temporarily stored. Storage means for storing offset information in which the radial position of the optical disc is associated with the second offset voltage for correcting the shift amount according to the radial position;
3. The correction unit according to claim 1, wherein the correction unit corrects the shift amount based on a third offset voltage obtained by adding or subtracting the first offset voltage to or from the second offset voltage. Optical disk device. A method for tracking control of an optical disc apparatus that reads and reproduces information recorded on an optical disc by an optical pickup,
A reflected light detection step of irradiating a light beam from the optical pickup and detecting reflected light from the optical disc;
A driving step of moving the optical pickup in a radial direction of the optical disc;
When the optical pickup crosses an arbitrary track of the optical disk by the driving step, a track cross signal representing a deviation amount of the light beam with respect to the track is calculated based on the reflected light detected in the reflected light detection step. A track cross signal generation process to be generated; and
A temperature detection step of detecting the temperature in the optical disc device;
When reproducing the optical disc, if the temperature detected by the temperature detection step becomes a predetermined temperature, the optical pickup is moved by a predetermined number of tracks by the driving step, and the track cross signal at the time of this movement is And a correction step of correcting the shift amount based on the calculated first offset voltage. A temporary storage step of temporarily storing information read by the optical pickup for a predetermined number of tracks;
A reproduction control step of sequentially reproducing the temporarily stored information;
The tracking control method according to claim 4, wherein the correction step moves the optical pickup within a range of the number of tracks temporarily stored. Storage means for storing offset information in which the radial position of the optical disc is associated with the second offset voltage for correcting the shift amount according to the radial position;
6. The correction step according to claim 4, wherein the correction step corrects the shift amount based on a third offset voltage obtained by adding or subtracting the first offset voltage to or from the second offset voltage. Tracking control method. The information recorded on the optical disc is read out by an optical pickup and reproduced by a computer of the optical disc apparatus.
A reflected light detection function for irradiating a light beam from the optical pickup and detecting reflected light from the optical disc;
A drive function for moving the optical pickup in the radial direction of the optical disc;
When the optical pickup crosses an arbitrary track of the optical disk by the driving function, a track cross signal representing a deviation amount of the light beam with respect to the track based on the reflected light detected by the reflected light detection function. A track cross signal generation function to generate,
A temperature detection function for detecting the temperature in the optical disc device;
When the temperature detected by the temperature detection function reaches a predetermined temperature during reproduction of the optical disc, the optical pickup is moved by a predetermined number of tracks by the driving function, and the track cross signal at the time of the movement is The tracking control program which implement | achieves the correction | amendment function which correct | amends the said deviation | shift amount based on the calculated 1st offset voltage. In the computer,
A temporary storage function for temporarily storing information read by the optical pickup for a predetermined number of tracks;
A playback control function for sequentially playing back the temporarily stored information;
Realized,
The tracking control program according to claim 7, wherein the correction function moves the optical pickup within a range of the number of tracks temporarily stored. Storage means for storing offset information in which the radial position of the optical disc is associated with the second offset voltage for correcting the shift amount according to the radial position;
The correction function corrects the shift amount based on a third offset voltage obtained by adding or subtracting the first offset voltage to or from the second offset voltage. Tracking control program.

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