JP2000200435A - Automatic adjusting device of track offset and automatic adjusting method of track offset, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the highly accurate tracking and to realize the stable recording/reproducing operation by setting the optical set condition and the track offset suitable for a high density optical disk with the land/groove specification to improve the error rate. SOLUTION: The track offset is preset for tracking to a track offset circuit 11 through a data bus 14, and the obtained flag error rate and a flag error rate obtained by changing the track offset the compared, then the track offset is changed to the direction where the flag error rate is reduced. The detection is made how the flag error rate is changed, thereby the track offset is optimized. Also by using a decision means to compare the crosstalk, when 1-7 modulations are executed at the time of overwriting, for instance, the objective track for the overwriting is recorded with 7T, and frequencies of the tracks at the both sides are recorded respectively as 8T, 6T, then the crosstalkes of the objective track with the tracks at the both sides are compared, and the track offset is changed and settled by the decision of the both crosstalk levels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic track offset adjusting device, an automatic track offset adjusting method, and a recording medium for an optical disk device. In particular, the present invention relates to an automatic track offset adjusting apparatus that sets a track offset suitable for a high-density optical disc of a land / groove specification, improves an error rate, performs high-accuracy tracking, and realizes stable recording and reproduction.

[0002]

2. Description of the Related Art An optical disc device requires high-accuracy tracking during reproduction and recording. Tracking in a conventional optical disk device will be described.

Japanese Patent Application Laid-Open No. 9-69234 discloses a focus servo circuit, a track servo circuit, a slide servo circuit, an error rate detection circuit, a track offset generation circuit,
An optical disk device for a CD-R having a track balance determination circuit and a track offset command circuit is disclosed. It detects the error rate of real-time information during recording / reproduction, controls the track offset, and improves tracking accuracy.

Further, recording and reproduction are performed on both lands / grooves of an optical disk, thereby realizing high density information. When recording is performed on both lands and grooves, more precise focus servo control and tracking servo control are required.

Japanese Patent Application Laid-Open No. 8-180429 discloses a land / groove optical disk apparatus provided with a switch for switching between a focus offset correction amount for tracking a land and a focus offset correction amount for tracking a groove. ing. By switching the focus offset correction amount and using different focus servo control signals for land / groove,
Getting the best focus.

[0006]

However, the conventional land / groove optical disk device increases the flag error rate or bit error rate of either the land or groove during overwriting to such an extent that the error cannot be corrected. In some cases, the recording / reproducing characteristics deteriorated.

FIG. 2 shows an example of a flag error rate (FER) characteristic with respect to the number of overwrites of a land / groove optical disk in a conventional optical disk device.
When overwriting is performed once, FER = 1%. The overwriting twice indicates a case where the data is once recorded and then overwritten. When overwriting is performed twice, for example, the land has FER = 1% as in the case of one overwriting.
However, as shown in the figure, the FER of the groove may be 20%. If the FER exceeds 30%, block distortion occurs, and the image quality is greatly reduced even in digital video recording.

[0008] In some cases, such an increase in FER occurs in lands and not in grooves. Also,
A similar problem may occur with the bit error rate.

Since it is not observed that both the land and the groove simultaneously cause such deterioration of the recording / reproducing characteristics, it is assumed that the flag error rate and the bit error rate are increased due to the influence of the track offset. . The rapid increase of the flag error rate and the bit error rate as shown in FIG. 3 is caused by the difference between the track offset setting state at the time of recording and reproduction in the initial state and the optical track offset setting state after overwriting. As a result, it has been found that the conventional land / groove optical disk device has problems in optical setting conditions and tracking.

The present invention has been made in view of the above problems, and has as its object to realize stable recording and reproduction by suppressing the bit error rate and flag error rate during overwriting. An automatic track offset adjusting device, an automatic track offset adjusting method, and a recording method which set an optical setting condition and a track offset suitable for a high density optical disc of land / groove specification, improve an error rate, and enable high-accuracy tracking. To provide a medium.

[0011]

Means for Solving the Problems In order to solve the above problems, the present invention has the following constitution. An automatic track offset adjusting device according to claim 1 includes an optical disk motor for driving an optical disk, an optical head movable in a focus direction and a tracking direction, a laser recording amplifier, a head amplifier, an equalizer, and a central data processing unit. An automatic track offset adjusting device of an optical disc device having a track offset circuit in which a track offset is preset via a data bus and a phase compensation circuit, wherein a track offset is set and a track is recorded or reproduced. Determining means for comparing the error rate of the track and the error rate when recording or reproducing the track by changing the track offset with an error rate allowable value specified in advance; and determining the error rate based on the determination result of the determining means. Track offset to change the track offset in the direction that A changing unit, based on the determination result of the determination means, characterized in that it comprises a track offset determining means for determining a track offset. The determining means can compare the flag error rate or the bit error rate. Further, the track offset can be adjusted for the track every revolution. An automatic track offset adjusting device according to a fifth aspect of the present invention provides an optical disk motor for driving an optical disk, an optical head movable in a focus direction and a tracking direction, a laser recording amplifier, a head amplifier, an equalizer, and a central data processing unit via a data bus. An automatic track offset adjusting device for an optical disk device having a track offset circuit for setting a track offset and a phase compensating circuit, wherein three different frequencies from a pulse given by a data modulation method are used, and a track to be overwritten and both sides thereof Recording control means for writing to the inner track and the outer track at different frequencies, and a determination to compare the crosstalk from the inner track and the crosstalk from the outer track for the target track. Means and the determination result of the determination means Based on, characterized in that it comprises a means for determining a track offset of the target track. Further, the recording control means performs 7T from the pulse given by the 1-7 modulation method,
Using three frequencies of 8T and 6T, the target track is set to 7
T, 8T for tracks on both sides, 6T for outer track
Can be written. The automatic track offset adjusting device according to the first to sixth aspects can automatically adjust the track offset of the land / groove optical disc. The optical disk device according to claim 8 is:
A track offset automatic adjusting device according to any one of claims 1 to 7 is provided. The track offset automatic adjustment method according to the ninth aspect includes an optical disk motor for driving an optical disk, an optical head movable in a focus direction and a tracking direction, a laser recording amplifier, a head amplifier, an equalizer, and a central data processing part. An automatic track offset adjusting method for an optical disc apparatus having a track offset circuit in which a track offset is preset via a data bus and a phase compensation circuit, wherein an error rate when a track is set and a track is recorded / reproduced is set. And the error rate when the track is recorded / reproduced with the track offset changed is compared with a predetermined error rate allowable value. Based on the comparison / determination result, the track offset is reduced in a direction in which the error rate decreases. And change the track And determining a set. As the error rate, a flag error rate or a bit error rate is used. The track offset automatic adjustment method according to the twelfth aspect provides an optical disk motor for driving an optical disk, an optical head movable in a focus direction and a tracking direction, a laser recording amplifier, a head amplifier, an equalizer, and a central data processing unit via a data bus. A track offset automatic adjusting method for an optical disk apparatus having a track offset circuit in which a track offset is set and a phase compensating circuit, comprising: Writing is performed at different frequencies on the inner track and the outer track on both sides, and for the target track, crosstalk from the inner track and
The crosstalk from the outer track is compared, and the track offset of the target track is determined based on the comparison result. If the data modulation method is 1-7
In the case of the modulation method, using frequencies of 8T, 7T, and 6T,
Target track is 7T, tracks on both sides are 8T, 6T
Can be recorded. According to the track offset automatic adjustment method of the ninth aspect, the track offset of the land / groove optical disk can be automatically adjusted. A recording medium according to a fifteenth aspect is characterized by recording a program capable of executing the track offset automatic adjustment method according to any one of the ninth to fourteenth aspects. The track offset automatic adjustment device, the track offset automatic adjustment method, and the recording medium of the present invention adjust the track offset by comparing and determining an error rate such as a flag error rate or a bit error rate of a land / groove optical disk. From the data modulation method used for optical disk recording, a frequency having an approximate amplitude characteristic is selected and recorded on the target track and tracks on both sides thereof, and the track offset is adjusted by balancing the crosstalk.

[0012]

Embodiments of the present invention will be described in detail below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration example of an embodiment of an automatic track offset adjusting apparatus according to the present invention. As shown in the figure, an automatic track offset adjusting device of an optical disk device according to the present embodiment includes an optical disk motor 4 for driving an optical disk 3, an optical head 5, an objective lens actuator 6, a laser recording amplifier (WAM) 13, a head It comprises an amplifier 8, an equalizer (EQL) 9, an error corrector (ECC) 10, a track offset (track offset circuit) 11, a phase compensation (phase compensation circuit) 12, a data bus 14, and a central data processing portion (CPU). .

The optical head 5 includes an objective lens actuator 6 for moving the objective lens in two axes of a focus direction and a tracking direction, an optical part and a photoelectric conversion part, and includes a servo amplifier 7. The signal reproduction output from the optical head 5 is amplified by the head amplifier 8 and equalized (E
QL) 9 to correct the frequency characteristics, and to use an error corrector (EC
C) Obtain video / audio / system signal output via 10. At this time, a flag error rate output is transmitted from the equalizer (EQL) 9 to the data bus 14. The CPU connected to the data bus 14 uses a flag error rate (F
ER) is calculated, and the quality of the recording / reproducing characteristics is determined. The data bus 1 is connected via a laser recording amplifier (WAM) 13.
4, the recording is performed by controlling the optical head 5 based on the settings of the recording power and the erasing power.

The device shown in FIG.
The track offset is preset in the track offset circuit 11 to record or reproduce, and the obtained flag error rate is changed or recorded or reproduced by changing the track offset, and the obtained flag error rate is compared. Change the track offset in a decreasing direction. It detects how the flag error rate changes depending on the setting of the track offset, and optimizes the track offset.

The tracking servo loop sets the track offset from the data bus, and after phase compensation,
Performs current conversion drive amplifier for electromagnetic drive.

FIG. 3 is a flow chart for explaining the operation of the embodiment of the track offset automatic adjusting apparatus according to the present invention. When the track offset automatic adjustment starts (S1), first, in order to adjust the track offset of the land, the track offset is set to 0 μm, the land power is set, recording / reproduction is performed, and a flag error rate is obtained (S2). Next, recording / reproducing is performed by applying a track offset, and a flag error rate is obtained (S
3). The obtained two flag error rates are compared and determined (S4).

If it is determined that the flag error rate is increased, the process returns to S2 and the track offset is 0 μm.
m, land power setting, record / reproduce, and obtain flag error rate. In S3, the polarity and level of the track offset to be applied are changed based on the determination result in the previous S4, and recording / reproduction is performed to obtain a flag error rate. The polarity and level of the track offset are changed and set so that the flag error rate decreases, and recording / reproduction is repeated.

If it is determined that the flag error rate is reduced, it is determined whether the obtained flag error rate is within an allowable range, for example, 1% or less (S4). Not acceptable (FER exceeds 1%)
In this case, the polarity and level of the track offset to be applied are changed until an allowable value is obtained (until the FER becomes 1% or less), so that the flag error rate is reduced and the track offset is maintained until the allowable value is obtained. Change the polarity and level and repeat recording / playback.

Next, for the groove, the track offset is set to 0 μm, the power of the groove is set, and recording / reproduction is performed to obtain a flag error rate (S5). Next, recording / reproduction is performed by applying a track offset to obtain a flag error rate (S6). The obtained two flag error rates are compared and determined (S7). Similarly to the land, the recording / reproduction is repeated by changing the polarity and level of the track offset until the flag error rate decreases and an allowable value is obtained.

The above-described automatic track offset adjustment is performed every time the optical disk makes one rotation. In the present embodiment, the flag error rate is used for the automatic adjustment determination of the track offset, but may be a bit error rate. Also, the track offset automatic adjustment may be performed only for the groove or only the land. In this embodiment, the allowable error rate is a flag error rate of 1
%, But may be set in accordance with the performance of the device or optical disk.

Since the automatic track offset adjusting apparatus and the automatic track offset adjusting method according to the first embodiment are configured as described above, the following effects can be obtained.

When recording / reproducing a flag error rate or a bit error rate of a land track or a groove track, the track offset is adjusted by comparing / determining the flag error rate or the bit error rate. it can. Since the track offset adjustment can be performed each time the optical disc makes one rotation, highly accurate tracking can be performed. Further, as shown in FIG. 1, there is no circuit for generating or instructing a track offset, and the configuration is simple. If a recording medium on which the track offset automatic adjustment method described in the present embodiment is recorded is used, it can be realized by a conventional optical disk device, and it is considered that the cost can be reduced.

(Embodiment 2) The configuration and operation of another embodiment of the present invention will be described. In the above-described embodiment, the track offset is adjusted so as to reduce the flag error rate and lead to an allowable value. However, in the present embodiment, the track offset is determined by determining the crosstalk level. Is to adjust.

In this embodiment, when overwriting, 2T, 3T, 4T, 5T, 6T, 7T, 8T
In the case of performing 1,7 modulation consisting of seven types of pulses, for example, a target track of overwriting is recorded at a 7T frequency, and the frequencies of tracks on both sides thereof are set to 8T and 6T, respectively.
And record. The crosstalk between the target track and the tracks on both sides is compared, and the track offset is determined from the determination of the crosstalk level of both tracks.

The determination means for comparing the crosstalk can be constituted by a band pass filter (BPF) and an AM detector. The apparatus shown in FIG. 1 is provided with a determination means for comparing crosstalk, and the reproduction output of the track to be track offset adjusted, the crosstalk from the inner track, and the crosstalk output from the outer track are determined by BP.
Amplify via F, perform AM detection, and compare.

FIG. 4 is a flowchart for explaining another operation of the embodiment of the automatic track offset adjusting apparatus of the present invention. When the track offset automatic adjustment is started (S8), the track offset is preset (S9), and the groove (G) is recorded at 8T frequency, the land (L) is recorded at 7T frequency, and the groove (G) is recorded at 6T frequency (S10). In steps S8 to S13, the center land and the target track are set, and track offset adjustment is performed. Here, the groove recorded at the 8T frequency is described as the inner track, and the groove recorded at the 6T frequency is described as the outer track. The optical head is returned to the center land recorded at the 7T frequency (S11), and crosstalk from the grooves on both sides is measured (S12). Next, whether the balance between the crosstalk from the inner circumferential groove and the crosstalk from the outer circumferential groove is within an allowable range,
For example, it is determined whether the difference is less than 2 dB (S1
3). If the crosstalk balance exceeds the allowable range, a track offset is applied to the outer circumference if the crosstalk from the inner groove is large, and a track offset is applied to the inner circumference if the crosstalk from the outer groove is large. Apply the offset. The track offset is changed and set (S9), and again, 8T is recorded on the groove, 7T is recorded on the land, and 6T is recorded on the groove (S10).
The optical head is returned to the center land recorded at the 7T frequency (S11), and crosstalk from the groove tracks on both sides is measured (S12). In S13, the balance of the crosstalk from the inner circumferential side and the outer circumferential side groove is measured. S8 to S13 are repeated until is within the allowable range.

Next, the track offset is preset (S14), and the land (L) is recorded at 8T frequency, the groove (G) is recorded at 7T frequency, and the land (L) is recorded at 6T frequency (S15). In steps S14 to S18, track offset adjustment is performed using the center groove as the target track. Here, the land track recorded at the 8T frequency is described as the inner side, and the land track recorded at the 6T frequency is described as the outer side. The optical head is returned to the central groove recorded at the 7T frequency (S16), and crosstalk from lands on both sides is measured (S17). Next, it is determined whether the balance of the crosstalk from the inner and outer lands is within an allowable range, for example, whether the difference is less than 2 dB (S18). If the crosstalk balance exceeds the allowable range, if the crosstalk from the groove on the inner circumference side is large, apply a track offset on the outer circumference side,
If the crosstalk from the outer circumferential groove is large, a track offset is applied to the inner circumferential side. The track offset is changed and set (S14), and again, 8T is recorded on the land, 7T is recorded on the groove, and 6T is recorded on the land (S15), and the optical head is returned to the center land recorded on the 7T frequency (S16). ), The crosstalk from the land tracks on both sides is measured (S17), and S14 to S18 are repeated until the balance of the crosstalk from the lands on the inner circumference side and the lands on the outer circumference reaches an allowable range.

In the present embodiment, among the pulses used in the 1-7 modulation system used in a 130 mm optical disk, 8T: 3.375 having a flat amplitude characteristic is used.
MHz, 7T: 3.86 MHz, 6T: 4.5 MHz. Because the amplitude characteristic is almost flat,
Crosstalk from the tracks on both sides to the target track is A
This is because the M-detected output balance easily reflects the track offset. Even when other data modulation methods are used, similar effects can be expected by selecting and using three frequencies having flat amplitude characteristics.

Since the automatic track offset adjusting device and the automatic track offset adjusting method according to the above-described embodiments are configured as described above, the following effects can be obtained.

From the data modulation method used for recording on the optical disk, a pulse having an approximate amplitude characteristic is selected and recorded on the target track and tracks on both sides thereof, and the track offset is adjusted by balancing the crosstalk. It is possible to suppress a decrease in recording / reproducing characteristics peculiar to the land / groove optical disk. Since the track offset adjustment can be performed each time the optical disc makes one rotation, highly accurate tracking can be performed. Further, similarly to the automatic track offset adjusting apparatus according to the above embodiment, there is no circuit for generating or instructing a track offset, and a bandpass filter and an AM detector are sufficient.
It is a simple configuration.

In the present embodiment, the present invention is not limited to this, and can be applied to an optical disk device suitable for applying the present invention. The automatic track offset adjusting device and the automatic track offset adjusting method as described in the first and second embodiments can be used together.

Further, the number, position, shape, etc. of the above-mentioned constituent members are not limited to the above-described embodiment, but can be set to a suitable number, position, shape, etc. for carrying out the present invention.

[0034]

The automatic track offset adjusting device, the automatic track offset adjusting method and the recording medium of the present invention are configured as described above, and have the following effects. Compares the track or bit error rate of tracks on land / groove optical discs
By judging and adjusting the track offset, and by selecting a frequency having an approximate amplitude characteristic from the data modulation method used for recording on the optical disk and recording it on the target track and the tracks on both sides thereof, and balancing the crosstalk,
Adjust track offset. At the time of reproduction and recording, track offset adjustment can be performed every time the optical disk makes one rotation. Therefore, high-precision tracking of the land / groove optical disk can be performed. The bit error rate and the flag error rate at the time of overwriting can be suppressed, and stable recording and reproduction can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of an embodiment of a track offset automatic adjustment device of the present invention.

FIG. 2 is a diagram showing an example of a flag error rate (FER) characteristic with respect to the number of overwrites of a land / groove optical disk in a conventional optical disk device.

FIG. 3 is a flowchart illustrating the operation of an embodiment of the track offset automatic adjustment device of the present invention.

FIG. 4 is a flowchart illustrating another operation of the automatic track offset adjusting device according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 3 optical disk 4 optical disk motor 5 optical head 6 objective lens actuator 7 servo amplifier 8 head amplifier 9 equalizer (EQL) 10 error corrector (ECC) 11 track offset circuit 12 phase compensation circuit 13 laser recording amplifier 14 data bus

Claims (15)

[Claims] An optical disk motor for driving an optical disk, an optical head movable in a focus direction and a tracking direction, a laser recording amplifier, a head amplifier, an equalizer, and a track offset from a central data processing portion via a data bus. A track offset automatic adjustment device of an optical disc device having a preset track offset circuit and a phase compensation circuit, wherein the track offset is set, and an error rate when recording or reproducing a track is performed; Determining means for comparing an error rate when recording or reproducing the track by changing the track offset with an error rate allowable value specified in advance; and reducing the error rate based on the determination result of the determining means. Track offset changing means for changing the track offset in a direction; A track offset determining means for determining a track offset based on a determination result of the determination means. 2. The automatic track offset adjusting device according to claim 1, wherein said determining means compares a flag error rate. 3. The track offset automatic adjustment device according to claim 1, wherein said determination means compares bit error rates. 4. The automatic track offset adjusting apparatus according to claim 1, wherein the track offset is adjusted for the track every one rotation. 5. An optical disk motor for driving an optical disk, an optical head movable in a focus direction and a tracking direction, a laser recording amplifier, a head amplifier, an equalizer, and a track on which a track offset is set from a central data processing portion via a data bus. An automatic track offset adjusting device for an optical disc device having an offset circuit and a phase compensating circuit, comprising: a track to be overwritten; and inner tracks on both sides thereof, using three frequencies from a pulse given by a data modulation method. Recording control means for writing to the outer track at a different frequency; determining means for comparing the target track with crosstalk from the inner track and crosstalk from the outer track; Based on the determination result of the determination means, the target Means for determining a track offset of a track. 6. The recording control means uses three frequencies of 7T, 8T, and 6T from a pulse given by a 1-7 modulation method, and writes the target track at 7T and tracks on both sides thereof at 8T and 6T. 6. The automatic track offset adjusting device according to claim 5, wherein: 7. The automatic track offset adjusting apparatus according to claim 1, wherein the track / offset automatic adjustment of the track / land optical disk is performed. 8. An optical disk device comprising the automatic track offset adjusting device according to claim 1. Description: 9. An optical disk motor for driving an optical disk, an optical head movable in a focus direction and a tracking direction, a laser recording amplifier, a head amplifier, an equalizer, and a track offset from a central data processing portion via a data bus. A track offset automatic adjustment method in an optical disc device having a preset track offset circuit and a phase compensation circuit, wherein the error rate when recording / reproducing a track by setting the track offset and the track offset The error rate at the time of recording / reproducing the track is changed and compared with a predetermined error rate allowable value, and the track offset is changed in a direction in which the error rate decreases based on the comparison / determination result. Determine the track offset based on the comparison and judgment results A method for automatically adjusting a track offset. 10. The method according to claim 9, wherein the error rate is a flag error rate. 11. The method according to claim 9, wherein the error rate is a bit error rate. 12. An optical disk motor for driving an optical disk, an optical head movable in a focus direction and a tracking direction, a laser recording amplifier, a head amplifier, an equalizer, and a track on which a track offset is set from a central data processing portion via a data bus. An automatic track offset adjustment method for an optical disk device having an offset circuit and a phase compensation circuit, comprising: using three different frequencies from a pulse given by a data modulation method; Write at a different frequency to the outer track and compare the crosstalk from the inner track with the crosstalk from the outer track for the target track, and based on the comparison result, the target track Determine the track offset for A method for automatically adjusting a track offset. 13. The method according to claim 1, wherein the data modulation method is a 1-7 modulation method, and the target track is written at 7T and tracks on both sides thereof are written at 8T and 6T using frequencies of 8T, 7T and 6T. 13. The automatic track offset adjusting method according to claim 12, wherein: 14. The track offset automatic adjustment method according to claim 9, wherein the track offset of the land / groove optical disk is automatically adjusted. 15. A recording medium on which a program capable of executing the track offset automatic adjusting method according to claim 9 is recorded.