JP3444822B2 - Optical disc reproducing apparatus and its calibration method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk reproducing apparatus and a calibration method thereof, and more particularly to an optical disk reproducing apparatus and a calibration method thereof for automatically adjusting a focus control system and a tracking control system before reproducing an optical disk.

[0002]

2. Description of the Related Art A conventional optical disk reproducing apparatus and its outline will be described below with reference to FIGS. FIG. 5 is a diagram for explaining the arrangement of each area on the optical disc.
FIG. 6 is a diagram showing an example of a conventional optical disc reproducing apparatus, FIG.
FIG. 6 is a diagram showing a calibration method of a conventional optical disc reproducing apparatus, and is a diagram showing a flowchart showing a case of a recordable MD (mini disc). The MD includes a recordable disc shown in FIG. 5A and a premastered disc shown in FIG. The recordable disc has a pit area in which concave and convex pits are spirally formed on an inner peripheral portion, and an information track area (also referred to as a groove area or a data area) including a spiral guide groove and an information mark on the outer side thereof. Note that the outer peripheral portion is provided with a mirror area in which no information mark or guide groove is formed. On the other hand, the pre-mastered disc has a mirror area where information pits are not formed on the outer peripheral portion, and an information track area (also referred to as a pit area or a data area) where information is formed by concave and convex pits on the inner peripheral portion. ing.

As described above, the optical disc reproduced by the optical disc reproducing apparatus shown in FIG. 6 is formed with a spiral information track composed of information marks or irregular information pits to be reproduced by utilizing the Kerr effect. . Optical head 11
Then, laser light is emitted from a laser light source (not shown),
This laser light is condensed by an objective lens (not shown) and irradiated on a target position on the disk medium, and information is read from the reflected light from the optical disk. The optical head 11 is composed of an optical system and a drive system. The optical system is
A mechanism for focusing laser light on the disk medium and detecting the deviation between the laser beam spot and the target position on the disk medium. Laser light source, lenses, beam splitter, photodiode (photodetector)
Etc.

The drive system moves the objective lens in the normal direction of the optical disc surface to control the laser light to form a beam spot spot on the optical disc surface, and the objective lens in the radial direction of the optical disc. Tracking control to control the light spot to scan on the center line of the information track by moving the light spot to follow the track shake, and determine the positional relationship between the target position on the disk medium and the laser light spot. It is a drive mechanism for maintaining a predetermined relationship, and is mainly composed of a magnet, a coil, a support member, an actuator, and the like.
In the tracking control, a tracking error signal indicating a tracking error is detected by a known method such as a one-beam push-pull method, a tracking actuator is driven based on the tracking error signal, and the objective lens is parallel to the surface of the disk medium. And in its radial direction. When performing an access operation or the like, the moving means 21 sends the sled in the radial direction of the optical disc to move the optical head 11 in the radial direction of the optical disc.

First, the general operation of the optical disk reproducing apparatus shown in FIG. 6 will be briefly described below. The reflected light from the optical disk is incident on the photodetector built in the optical head 11 via the deflection beam splitter built in the optical head 11, is received by the photodetector, is photoelectrically converted, and is supplied to the head amplifier 13 as a signal S3. The head / head amplifier 13 amplifies and calculates the signal S3. The head amplifier 13 may be built in the optical head 11. The head amplifier 1
The output from 3 is supplied to the buffer means 15. The output S4 of the buffer means 15 is supplied to the demodulation circuit 17, and the reproduction signal is output from the demodulation circuit 17. The demodulation circuit 17 expands the compressed digital information.

On the other hand, necessary ones of the calculation results in the head amplifier 13 are supplied to the focus & tracking control means 23 and the calibration means 35. The focus & tracking control means 23 includes a focus control means and a tracking control means, and a focus error signal obtained by the astigmatism method or the Foucault method is supplied to the focus control means. The objective lens of the optical head 11 is controlled by an actuator (not shown) to move in a direction perpendicular to the surface of the optical disc in accordance with the focus error signal so that a beam spot is formed on the recording surface of the optical disc. .

A tracking error signal generated by a well-known method such as a one-beam push-pull method is supplied to the tracking control means, and an actuator for moving an objective lens is driven according to the tracking error signal, and an optical An object lens in the head or the optical head is moved in the radial direction of the optical disk. The actuator is built in the optical head 11 and is not shown.

First, a recordable MD to be reproduced
When the (mini disk) is mounted on the optical disk reproducing device 40, the rotation control of the reproducing device and the focus pull-in (focus search) of the optical head 11 are performed (step S11) and a microprocessor (hereinafter referred to as MPU).
A signal SC indicating the start of calibration is supplied to the buffer means 15, the focus & tracking control means 23, and the calibration means 35 from (also referred to as 26). Then, the input to the buffer unit 15 is prohibited, the tracking control is canceled (hereinafter, also referred to as OFF), and the calibration unit 35 performs focus &
Calibration of the tracking control means 23 is started. Less than,
Unless otherwise specified, the calibration means automatic adjustment of the focus control means and the tracking control means performed before reproducing the optical disc.

In step S13, when the pit area formed in the innermost peripheral portion of the recordable MD is irradiated with the beam spot, the process proceeds to step S15, and the thread is slightly sent to the outer peripheral side. As a result, the irradiation position of the light beam is slightly changed to the outer peripheral side and enters the groove area. If the groove area is not entered once, steps S13 and S15 are repeated. Step S
If it is determined in 13 that the area other than the pit area of the recordable MD is read, the process proceeds to step S17, the tracking control system is adjusted in step S17, and the process proceeds to step S19. In the adjustment of the tracking control system, the offset (balance) adjustment of the tracking error signal is performed in the tracking OFF state, and then in the tracking ON state, the loop gain of the tracking control system is automatically adjusted to a predetermined value. It Step S19
Then, it is determined whether the characteristic or the set value of the tracking control system after the gain adjustment in step S17 is within the predetermined range (determination 1). The characteristic of the tracking control system is an open loop gain characteristic, an open loop phase characteristic, a closed loop gain characteristic, a zero cross frequency, etc. of the tracking control system, and the set value is after automatic adjustment at a check point in the tracking control system. Voltage, etc.

When it is judged in the judgment 1 that the characteristic or set value of the tracking control system is not within the predetermined range,
Returning to step S17, step S17 and step S19
Is repeated. When it is determined in step S19 that the characteristic or set value of the tracking control system is within the predetermined range, the process proceeds to step S23. In step S23, offset adjustment and gain adjustment of the focus control system are performed, and the flow advances to step S25. In step S25, it is determined whether the characteristic or set value of the focus control system is within a predetermined range (determination 2). If it is not within the predetermined range, the process returns to step S23, and steps S23 and S25.
Is repeated. When it is determined in the determination 2 that the characteristic or set value of the focus control system is within the predetermined range, the process proceeds to step S27, and in step S27, adjustments other than the focus control system and the tracking control system are performed.

Focus and tracking control means 2
The calibration of No. 3 is performed every time the disc is replaced in order to suppress a control error caused by variations in the reflectance of the optical disc, the inclination of the optical disc, and the like. When the calibration is completed, M
The signal SC indicating the end of calibration from the PU 26 is the buffer means 1
5, the focus & tracking control means 23 and the calibration means 35 are supplied, and the calibration is completed.

[0012]

In the conventional optical disc reproducing apparatus, in the automatic adjustment of the focus control system and the tracking control system performed immediately after mounting the optical disc, if the optical disc reproducing apparatus is provided with a switch called a start limit switch. First, the optical head is moved to the innermost peripheral portion, and the optical head is slightly moved from the position to the outer peripheral side of the optical disk, and the calibration (automatic adjustment) is performed in a state where the light beam is scanning the data area. Is done. The start limit switch is for limiting the moving range of the optical head so as not to go too far to the inner peripheral side when the optical head is moved to the innermost peripheral part.

However, the installation of the start limit switch may be omitted in order to downsize the device or reduce the manufacturing cost. In the optical disc reproducing apparatus which does not have the start limit switch, the focus & tracking controller is calibrated by the conventional method as shown in FIG. In the conventional calibration method, when the calibration is started, the automatic adjustment of the optical disk reproducing device fails because it is not known which area on the optical disk the light beam spot from the optical head irradiates. was there.

Specifically, in the conventional calibration method, the calibration of the focus control system and the tracking control system is performed as shown in FIG.
The groove area <data area> of the recordable disk shown in (A) or the pit area (data area) of the premastered disk shown in FIG. It is difficult to control the position of the optical head so as to scan the data area. If the tracking control system is calibrated while the light beam spot is irradiating the mirror area on the outermost periphery of the optical disc, steps S17 and S19 shown in FIG. In some cases, the automatic adjustment is forcibly completed before proceeding to step S23, or the calibration operation is forcibly terminated without proceeding to step S23. The present invention has been made in view of the above problems, and an object thereof is an optical disc reproducing apparatus and a calibration method thereof which can surely perform automatic adjustment of a focus control system and a tracking control system without including a start limit switch. Is to provide.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the first invention has a mirror area in which information is not recorded in the outer peripheral portion, and has a circular shape (hereinafter referred to as a circular shape). An optical head for reading information from an optical disk having a data area having a spiral or concentric information track formed on the inner periphery of the mirror area; and a moving means for moving the optical head in the radial direction of the optical disk. Focus control means for performing focus control of the optical head, tracking control means for performing tracking control of the optical head, and calibration means for automatically adjusting the focus control means and the tracking control means before reproducing the optical disc. In an optical disc reproducing apparatus equipped with
The calibration means has a characteristic determination means for determining whether or not the characteristic or the set value of the tracking control means is within a predetermined range after the gain adjustment in the tracking control means, and the optical disc reproduction apparatus sets the reproduction target as a reproduction target. When the optical disc is loaded, the focus control unit first pulls in the focus, and when the characteristic determination unit determines that the characteristic is not within the predetermined range, the calibration unit moves the optical head. It is an optical disk reproducing apparatus in which the gain is adjusted again by the tracking control means by moving the optical disk in the inner peripheral direction by means.

According to the present invention, in both the recordable disc and the premastered disc, when the tracking control system is calibrated, the light beam emitted from the optical head scans the mirror region arranged on the outer periphery of the optical disc. During this time, an abnormality is detected by checking whether the characteristic or set value of the tracking control system is within a predetermined range by the characteristic determining means provided in the calibrating means. That is, after the gain adjustment of the tracking control system is completed, it is determined that the characteristic or set value of the tracking control system is not within the range of the predetermined value. In this case, the optical head is forcibly moved in the inner peripheral direction of the optical disc. Then, by performing the movement once or more, the beam spot surely scans the data area. Since the tracking control system is automatically adjusted in the data area, it is possible to reliably perform the automatic adjustment of the tracking control system even in an optical disc reproducing apparatus that does not have a start limit switch.

A second invention is the same as the first invention,
When the gain adjustment of the focus control means is performed after the gain adjustment in the tracking control means, and then the characteristic determination means determines that the characteristic or set value of the focus control system is not within a predetermined range, the calibration means The optical disc reproducing apparatus is configured such that the optical head is moved again in the inner circumferential direction of the optical disc by the moving unit to perform the gain adjustment of the tracking control unit and the gain adjustment of the focus control unit again.

According to the present invention, in the automatic adjustment of the tracking control system and the focus control system, although the gain adjustment of the tracking control system is incomplete, the characteristic or the set value of the tracking control means is predetermined for some reason. It may be determined to be within the range. For example, there is a case where the tracking control system is automatically adjusted while the beam spot is scanning near the boundary between the mirror area and the data area. If the gain adjustment of the focus control system is performed in a state where the steps prior to the gain adjustment of the focus control system are not normally performed, the characteristic or set value of the focus control system deviates from the predetermined range, and Abnormalities in the previous process may be detected. When the abnormality is detected, the sled is again sent to the inner circumference to surely move the optical head to the data area, and then the automatic adjustment is performed. Therefore, there is an effect that the automatic adjustment is surely performed.

A third invention is an optical head for reading information from an optical disk having a mirror area where information is not recorded on the outer peripheral portion and a data area having a circular information track formed on the inner peripheral portion of the mirror area. A moving means for moving the optical head in the radial direction of the optical disc, a focus control means for controlling the focus of the optical head, a tracking control means for performing the tracking control of the optical head, and before reproducing the optical disc. In a method of calibrating an optical disc reproducing apparatus comprising the focus control means and a calibrating means for automatically adjusting the tracking control means, when an optical disc to be reproduced is mounted on the optical disc reproducing apparatus, first the focus control means causes focus pull-in. And then the calibration means
If it is determined whether or not the characteristic or set value of the tracking control means is within a predetermined range after the gain adjustment of the tracking control means, and it is determined that the characteristic is not within the predetermined range, the optical head is It is a method of calibrating an optical disk reproducing apparatus, wherein the moving means moves the optical disk in the inner peripheral direction and the gain of the tracking control means is adjusted again.

According to the present invention, in the automatic adjustment of the tracking control system and the focus control system, even if the gain adjustment of the first tracking control system ends abnormally, the characteristic judgment provided in the calibration means is performed. The abnormality is detected by the means, and the optical head is forcibly moved one or more times in the radial direction of the optical disc. Then, since the tracking control system is automatically adjusted while the beam spot is scanning the data area of the optical disc, the automatic adjustment of the tracking control system can be surely performed even in the optical disc reproducing apparatus which does not have the start limit switch. You can

A fourth invention is the same as the third invention,
If the gain of the focus control means is adjusted after the gain adjustment of the tracking control means, and then the characteristic determination means determines that the characteristic or set value of the focus control system is not within a predetermined range, the optical head It is a method of calibrating an optical disk reproducing apparatus, wherein the optical disk reproducing apparatus is moved again in the inner circumferential direction to perform gain adjustment of the tracking control means and gain adjustment of the focus control means.

According to the present invention, after the adjustment of the tracking control system or the focus control, when the characteristic or the set value of each control system is not within the predetermined range, the sled is sent to the inner circumference to move the optical head to the inner circumference side of the optical disk. To
In addition, the tracking control system and the focus control are automatically adjusted again. As a result, even if there is an erroneous determination that an abnormality is not detected even though the normal adjustment is not performed in any of the adjustment steps, the automatic adjustment can be surely and accurately performed.

A fifth aspect of the present invention is an optical head for reading information from an optical disk having a mirror area in which information is not recorded on the outer peripheral portion and a data area having a circular information track formed on the inner peripheral side of the mirror area. A moving means for moving the optical head in the radial direction of the optical disc, a focus control means for controlling the focus of the optical head, a tracking control means for performing the tracking control of the optical head, and before reproducing the optical disc. In an optical disk reproducing device including the focus control means and a calibration means for automatically adjusting the tracking control means,
When the optical disc to be reproduced is mounted on the optical disc reproducing apparatus, first, the focus control unit performs focus pull-in, and then the calibration unit determines whether the region read by the optical head is a mirror region or a region other than the mirror region. If the area determination means determines that the optical head is reading the mirror area, the calibration means moves the optical head to the optical disk by the moving means. Of the tracking control means and the focus control means after the area determination means determines that the optical head is reading a region other than the mirror area. It is an optical disk reproducing device for performing gain adjustment.

In the present invention, prior to automatic adjustment of the tracking control system and the focus control system, the focus control means first pulls the focus. When the optical disk to be reproduced is a recordable disk, the position of the optical head is controlled so that the beam spot scans the area other than the pit area of the optical disk, but in the premastered disk, this step is omitted and not executed. Next, the amplitude of the tracking error signal (track crossing signal in this case) is observed with the tracking control turned off. If the amplitude is large, it is determined that the light beam is scanning the data area, and if the amplitude is small, It is determined that the light beam is scanning the mirror area. Then, when the mirror area is being scanned, the position of the optical head is moved to the inner peripheral side by sending the sled to the inner peripheral side. This process may be repeated multiple times. When it is determined that the data area is being scanned, the gain adjustment of the tracking control system and the gain adjustment of the focus control system are performed. As described above, the amplitude of the tracking error signal can be easily detected by turning off the tracking control and observing the amplitude of the so-called track crossing signal. As a result, even in an optical disk reproducing apparatus that does not have a start limit switch, it is possible to reliably perform automatic adjustment of the tracking control system and the focus control system in the data area.

A sixth aspect of the present invention is an optical head for reading information from an optical disk having a mirror area in which information is not recorded on the outer peripheral portion and a data area having a circular information track formed on the inner peripheral side of the mirror area. A moving means for moving the optical head in the radial direction of the optical disc, a focus control means for controlling the focus of the optical head, a tracking control means for performing the tracking control of the optical head, and before reproducing the optical disc. In a method of calibrating an optical disc reproducing apparatus comprising the focus control means and a calibrating means for automatically adjusting the tracking control means, when an optical disc to be reproduced is mounted on the optical disc reproducing apparatus, first the focus control means causes focus pull-in. And then the calibration means
Before adjusting the gain of the tracking control means, a region determination is made as to whether the region read by the optical head is a mirror region or a region other than the mirror region, and the optical head is reading the mirror region. When it is determined that the optical head is moved in the inner circumferential direction of the optical disc to perform the area determination again, and after it is determined in the area determination that the optical head is reading a region other than the mirror region, It is a method of calibrating an optical disk reproducing device, wherein the gain adjustment of the tracking control means and the focus control means is performed.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION
It is an optical disk reproducing apparatus that does not necessarily have a start limit switch and is capable of reliably performing automatic adjustment (calibration) of a tracking control system and a focus control system. In the present invention, in the automatic adjustment, the gain adjustment of the tracking control system and the gain adjustment of the focus control system are performed while the optical head is scanning the data area of the optical disc. Therefore, after adjusting the gain of the tracking means, it is determined whether the characteristic or set value of the tracking control system is within a predetermined range. When it is determined that the mirror area is being scanned, a thread for moving the optical head in the radial direction of the optical disc is slightly sent to the inner peripheral side of the optical disc. After the gain adjustment of the tracking control system, the confirmation of the characteristics, and the feeding of the sled are performed once or a plurality of times to confirm that the optical disk is scanning the data area, the adjustment state by the automatic adjustment is fixed.

Before adjusting the gain of the tracking control system, it is first determined whether or not the optical disc is scanning the data area. If the optical disc is scanning other than the data area, the thread is set to the optical disc. If it is confirmed that the optical head scans the data area by sending to the inner circumference side, the gains of the tracking control means and the focus control means may be adjusted. An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing a first embodiment of an optical disk reproducing apparatus of the present invention, FIG. 2 is a flowchart showing a calibration method thereof, and is a flowchart showing a case of a recordable MD (mini disk). . As shown in FIG. 5, there are a recordable disc and a premastered disc as the optical discs reproduced by the optical disc reproducing apparatus of the present invention. Here, the case of the recordable disc will be described as an example. 1 and 3, elements having the same functions and functions as those of FIG. 6 are designated by the same reference numerals, and description thereof may be omitted. In addition, in FIG. 2 and FIG.
Steps corresponding to those in FIG. 7 are designated by the same reference numerals, and description thereof may be omitted.

The optical disk reproducing apparatus 10 shown in FIG. 1 is different from the optical disk reproducing apparatus 40 shown in FIG.
1 is different from the flow chart shown in FIG. 7 in that the flow chart shown in FIG.
The steps after step S17 are different. First, when a recordable MD (mini disk) to be reproduced is mounted on the optical disk reproducing apparatus 10, rotation control of the disk and focus pull-in (focus search) of the optical head 11 are performed (step S11), and at the same time, a micro A signal SC indicating the start of calibration is supplied from the processor (hereinafter, also referred to as MPU) 25 to the buffer unit 15, the focus & tracking control unit 23, and the calibration unit 31. Then, the input to the buffer unit 15 is prohibited, the tracking control is canceled (hereinafter, also referred to as OFF), and the calibration unit 31 starts the calibration of the focus & tracking control unit 23.

Here, whether or not the position on the optical disk surface where the beam spot is currently irradiated is the pit area in which the uneven information pit is formed is determined based on the signal S5 output from the head amplifier 13. It is checked by the calibration means 31 (step S13). Specifically, the reflected light from the optical disc is I and J
The RF signal generated from the signal corresponding to the sum of the I light and the J light is large, but it is determined to be a pit area, and if it is small, it is determined to be a data area. .

In step S13, when the beam spot is applied to the pit area formed on the inner peripheral portion of the recordable MD, the process proceeds to step S15, and the moving means 2 is moved.
One thread is slightly sent to the outer peripheral side. As a result, the irradiation position of the light beam is slightly changed to the outer peripheral side and enters the groove area. If the groove area is not entered once, steps S13 and S15 are repeated.
If it is determined in step S13 that the area other than the pit area is being read, the process proceeds to step S17 and step S17.
Then, the tracking control system is adjusted and the process proceeds to step S19. In the adjustment of the tracking control system, offset (balance) adjustment of the tracking error signal is performed in the tracking OFF state, and then tracking ON
In this state, the loop gain of the tracking control system is automatically adjusted to a predetermined value. In step S19, it is determined whether the characteristic or set value of the tracking control system after the gain adjustment in step S17 is within a predetermined range (determination 1). The characteristic of the tracking control system is an open loop gain characteristic, an open loop phase characteristic, a closed loop gain characteristic, a zero cross frequency, etc. of the tracking control system, and the set value is after automatic adjustment at a check point in the tracking control system. Voltage, etc.

If it is judged in the judgment 1 that the characteristic or set value of the tracking control system is not within the predetermined range, the process proceeds to step S21. In step S21, the moving means 2
The optical head 11 is slightly moved to the inner peripheral side of the optical disk by sending the thread 1 to the inner peripheral side slightly, and the process proceeds to step S17. Steps S17 to S21
Up to step S19 (determination 1) are repeated until it is determined that the characteristic or set value of the tracking control system is within the predetermined range. If it is determined in the determination 1 that the characteristic or set value of the tracking control system is within the predetermined range, the process proceeds to step S23.

In step S23, offset adjustment and gain adjustment of the focus control system are performed, and the flow advances to step S25. In step S25, it is determined whether or not the characteristic or set value of the focus control system is within a predetermined range (determination 2). If it is not within the predetermined range, step S2
Returning to step 1, steps S21 and S17 and subsequent steps are repeated. The determination 2 is performed by the characteristic determination unit included in the calibration unit 31. When it is determined in the determination 2 that the characteristic or the set value of the focus control system is within the predetermined range, the process proceeds to step S27. At step 27, automatic adjustment of, for example, a tilt control system other than the focus control means and the tracking control means is performed as necessary.

Focus and tracking control means 2
The calibration of No. 3 is performed every time the disc is replaced in order to suppress a control error caused by variations in the reflectance of the optical disc, the inclination of the optical disc, and the like. When the calibration is completed, M
The signal SC indicating the end of calibration from the PU 25 is the buffer means 1
5, the focus & tracking control means 23 and the calibration means 35 are supplied, and the calibration is completed. In the first embodiment, after the gain of the tracking control system or the focus control system is adjusted, if the characteristic or the set value of the tracking control system or the focus control system shows an abnormal characteristic that is not within a predetermined range, the optical head 11 Is sent to the inner peripheral side of the optical disc, and the automatic adjustment is redone from the tracking control system. This is because the tracking control system and the focus control system are not completely independent, and there are elements shared by both systems, such as the objective lens and actuator, so that they do not interfere with each other to some extent. The automatic adjustment is redone to solve the problem.

As described above, it is determined in step S25 whether or not the characteristics and set values of the focus control system are within a predetermined range. The step S
The case of returning from S25 to S21 will be described. In step S17, the gain adjustment of the tracking control system is not normally completed, but if no abnormality is detected in step S19, step S23 is performed.
Go to. Then, under the influence of the abnormal adjustment of the tracking control system, in step S25, the adjustment value or the characteristic of the focus control system may exceed a predetermined range. In such a case, the beam spot is the mirror area of the optical disc,
Alternatively, assuming that there is a high possibility that scanning is performed near the boundary between the mirror area and the data area, the process returns to step S21, the thread is sent to the inner circumference side of the optical disc, and the tracking control system and the focus control system are automatically adjusted. Is done again. If the reproduced optical disk is a premastered disk, steps S13 and S15 shown in FIG. 2 are omitted.

Next, a second embodiment of the optical disk reproducing apparatus of the present invention will be described with reference to FIGS. FIG. 3 is a block diagram showing a second embodiment of the optical disc reproducing apparatus of the present invention, and FIG. 4 is a flow chart of the calibration method thereof, which is a flow chart in the case of a recordable MD (mini disc). . The area arrangement of the recordable MD is as shown in FIG. The optical disc reproducing apparatus 20 shown in FIG. 3 is different from the optical disc reproducing apparatus 10 shown in FIG. 1 in that the calibrating means 32 has a region determining means, and the flowchart shown in FIG. 4 is the flowchart shown in FIG. In contrast, the steps after step S17 are different.

First, a recordable MD to be reproduced
When the (mini disk) is mounted on the optical disk reproducing device 20, the rotation control of the disk and the focus pull-in (focus search) of the optical head 11 are performed (step S11), and the microprocessor (hereinafter referred to as MPU).
25), a signal SC indicating the start of calibration is supplied to the buffer means 15, the focus & tracking control means 23, and the calibration means 31. Then, the input to the buffer unit 15 is prohibited, the tracking control is canceled (hereinafter, also referred to as OFF), and the calibration unit 31 performs focus &
Calibration of the tracking control means 23 is started.

Here, it is checked whether or not the position where the beam spot is currently irradiated is the pit area on the inner circumference side of the optical disk (step S13). This is done in the calibration means 32 using the amplitude of the regenerated RF signal. In step S13, when the beam spot is applied to the pit area formed on the inner peripheral side of the recordable MD, the process proceeds to step S15, and the thread of the moving means 21 is slightly sent to the outer peripheral side. As a result, the irradiation position of the light beam is slightly changed to the outer peripheral side and enters the groove area. If the groove area is not entered once, steps S13 and S15 are repeated.

When it is determined in step S13 that the area other than the pit area of the recordable MD is read, the process proceeds to step S16. In step S16, the tracking control is turned off and the amplitude of the tracking error signal (here, the track crossing signal) is detected. If the amplitude is larger than a predetermined value, it is determined that the light beam is scanning the data area. Otherwise, it is determined that the light beam is scanning the mirror area. If the amplitude of the tracking error signal is smaller than the predetermined value in step S16, step S2
Go to 1. In step S21, the thread is slightly sent to the inner circumference side, and the process proceeds to step S16. Steps S16 and S21 are repeated until the amplitude of the tracking error signal reaches a predetermined value or more in step S16. Thus, in step S16, it is determined where the area on the optical disc being scanned is.

When it is determined in step S16 that the amplitude of the tracking error signal is equal to or larger than the predetermined value, step S1
In step S23, the gain of the tracking control system is adjusted, and then in step S23, the gain of the focus control system is adjusted. In step S27, adjustments other than the tracking control system and the focus control system are performed as necessary. The calibration is completed. When the calibration ends, a signal SC indicating the end of calibration is supplied from the MPU 25 to the buffer unit 15, the focus & tracking control unit 23, and the calibration unit 35, and the calibration ends. If the optical disc to be played is a premastered disc,
Steps S13 and S15 are omitted.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of an optical disc reproducing apparatus of the present invention.

FIG. 2 is a diagram showing a first embodiment of a calibration method for an optical disc reproducing apparatus of the present invention.

FIG. 3 is a block diagram showing a second embodiment of the optical disc reproducing apparatus of the present invention.

FIG. 4 is a diagram showing a second embodiment of the calibration method of the optical disc reproducing apparatus of the present invention.

FIG. 5 is a diagram illustrating the arrangement of areas in an optical disc.

FIG. 6 is a diagram showing an example of a conventional optical disc reproducing apparatus.

FIG. 7 is a diagram showing a method of calibrating a conventional optical disc reproducing apparatus.

[Explanation of symbols]

11 optical head 13 head amplifier 21 moving means 23 focus & tracking control means 25 MPU 31, 32 calibrating means S11 focus search (focus pull-in) S13 Is reading a pit area? S15 Send the optical head to the outer circumference S16 Is the reading outside the mirror area? S17 Gain adjustment of tracking control system S19 Is the characteristic or set value of the tracking control system within a predetermined range? S21 Sending the optical head to the inner circumference side S23 Gain adjustment of the focus control system S25 Is the characteristic or set value of the focus control system within a predetermined range?

Claims (6)

(57) [Claims] 1. An optical head for reading information from an optical disc having a mirror area in which information is not recorded on the outer peripheral portion and a data area having a circular information track formed on the inner peripheral side of the mirror area, and the optical head. Moving means for moving the head in the radial direction of the optical disc, focus control means for performing focus control of the optical head, tracking control means for performing tracking control of the optical head, and the focus control before reproducing the optical disc. In the optical disc reproducing apparatus including a means and a calibrating means for automatically adjusting the tracking control means, the calibrating means determines whether or not a characteristic or set value of the tracking control means is within a predetermined range. It has a characteristic judging means for judging after the gain adjustment, If the characteristic determining means determines that the optical head is not within the range, the calibrating means moves the optical head in the inner peripheral direction of the optical disk by the moving means and adjusts the gain of the tracking control means again. An optical disk reproducing device characterized by the above. 2. If the gain adjustment of the focus control means is performed after the gain adjustment in the tracking control means, and then the characteristic determination means determines that the characteristic or set value of the focus control system is not within a predetermined range. 2. The calibration means re-adjusts the gain of the tracking control means and the gain of the focus control means by moving the optical head again in the inner circumferential direction of the optical disk by the moving means. Optical disk playback device. 3. An optical head for reading information from an optical disk having a mirror area in which information is not recorded on the outer peripheral portion and a data area having a circular information track formed on the inner peripheral side of the mirror area, and the optical head. Moving means for moving the head in the radial direction of the optical disc, focus control means for performing focus control of the optical head, tracking control means for performing tracking control of the optical head, and the focus control before reproducing the optical disc. In the method of calibrating an optical disc reproducing apparatus, the calibration means includes a calibration means for automatically adjusting the tracking control means, and the calibration means determines whether the characteristic or set value of the tracking control means is within a predetermined range. Judgment is made after the gain adjustment of the control means, and the characteristic is not within the predetermined range. If it is determined, the calibration method of the optical disk reproducing apparatus, characterized in that the optical head performs gain adjustment of the inner circumference again tracking control means is moved in the direction of the optical disk by the moving means. 4. When the gain adjustment of the focus control means is performed after the gain adjustment in the tracking control means, and then the characteristic determination means determines that the characteristic or set value of the focus control system is not within a predetermined range. 2. The method for calibrating an optical disk reproducing apparatus according to claim 1, wherein the optical head is moved in the inner circumferential direction of the optical disk again to adjust the gain of the tracking control means and the gain control of the focus control means. 5. An optical head for reading information from an optical disk having a mirror area in which information is not recorded on the outer peripheral portion and a data area having a circular information track formed on the inner peripheral side of the mirror area, and the optical head. Moving means for moving the head in the radial direction of the optical disc, focus control means for performing focus control of the optical head, tracking control means for performing tracking control of the optical head, and the focus control before reproducing the optical disc. In the optical disc reproducing apparatus including a measuring unit and a calibrating unit that automatically adjusts the tracking control unit, the calibrating unit determines whether the region read by the optical head is a mirror region or a region other than the mirror region. Area determining means, wherein the optical head is the mirror in the area determining means. When it is determined that the area is being read, the calibrating means moves the optical head in the inner circumferential direction of the optical disc by the moving means, and the area deciding means makes the decision again. An optical disk reproducing apparatus, wherein the gain of the tracking control unit and the focus control unit is adjusted after it is determined that the optical head is reading a region other than the mirror region. 6. An optical head for reading information from an optical disc having a mirror area in which information is not recorded on the outer peripheral portion and a data area having a circular information track formed on the inner peripheral side of the mirror area, and the optical head. Moving means for moving the head in the radial direction of the optical disc, focus control means for performing focus control of the optical head, tracking control means for performing tracking control of the optical head, and the focus control before reproducing the optical disc. In the method of calibrating an optical disc reproducing apparatus, the calibration means includes a calibration means for automatically adjusting the tracking control means, and the calibration means adjusts the area read by the optical head before adjusting the gain of the tracking control means. Performs a region determination of whether it is a mirror region or a region other than the mirror region, and If it is determined that the optical head is reading the mirror area, the optical head is moved in the inner circumferential direction of the optical disc to perform the area determination again, and the optical head is determined to be other than the mirror area in the area determination. A method for calibrating an optical disc reproducing apparatus, characterized in that the gain adjustment of the tracking control means and the focus control means is performed after it is determined that the reading is performed.