JP2000090437A - Recording power setting method and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably and repeatedly record data. SOLUTION: When an optical disk is loaded in ST1, optimum resolution data is read out and stored. Optimum recording power is set in ST2. Specific pattern data PTD is written with optimum recording power in ST3. Specific pattern data is reproduced, and optimum reproducing power optimum in resolution is set in ST4. A recording unit for recording data is reproduced, and optimum reproducing power is discriminated for every recording unit in ST5. The ratio of optimum reproducing power to optimum reproducing power discriminated for every recording unit is calculated in ST6. Optimum recording power is compensated by using the ratio in ST7. Data is recorded with compensated recording power in accordance with respective recording units in ST8. Even if sensitivity is different from each recording unit, the recording power of a laser beam is controlled in accordance with respective recording unit, thus the data can be recorded stably and repeatedly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a recording power setting method and an optical disk apparatus. More specifically, the optical disk is irradiated with a light beam at a first recording power to record specific pattern data, a first reproducing power capable of optimally reproducing the recorded specific pattern data is detected, and written for each recording unit. A second reproduction power capable of optimally reproducing the data which has been recorded is detected, and a correction value is obtained for each recording unit from the first reproduction power and the second reproduction power. By correcting the first recording power using the value, it is possible to stably repeat data recording.

[0002]

2. Description of the Related Art With the development of digital technology, image information and music information have been recorded on rewritable optical disks which have been used for data recording of computer devices, and the capacity of optical disks has been increased. Is planned.

In recent years, as a technique for increasing the capacity of the optical disc, an MSR (Magnetic Super Resolutio) has been developed.
An n) -type super-resolution optical disk has been proposed.

[0004] The MSR system is basically a FAD (Front Ap
erture detection), RAD (Rear Aperture Dete)
ction) method and CAD (Center Aperture Detection) method.

Here, for example, as shown in FIG. 5, an optical disk of a CAD system has a reproducing layer 101 which has an in-plane magnetization state at room temperature and a perpendicular magnetization state as the temperature rises.
A recording layer 102 on which recording data is recorded as magnetic field information. At the time of data recording, a magnetic field modulated by the recording data is applied from the magnetic head to the recording layer of the optical disk, and a light beam (laser light) is pulse-irradiated in synchronization with the recording data, so that the recording data is recorded as magnetic field information. Recorded in 102. Also, at the time of data reproduction, by irradiating a laser beam and setting the temperature of a region smaller than the laser spot diameter of the reproduction layer 101 to a threshold Th or more, the reproduction layer 101 is changed from an in-plane magnetization state to a perpendicular magnetization state to thereby aperture. W is formed. Here, the magnetization direction of the reproduction layer 101 in the aperture W is
And the recording layer 102 is magnetostatically coupled to each other and is determined by a leakage magnetic field from the recording layer 102. Therefore, it is necessary to read out recorded data written in the recording layer 102 by a magneto-optical effect based on the magnetization state of the reproducing layer in the aperture W. Can be. As described above, information in an area smaller than the laser spot diameter can be extracted, and the cutoff frequency fs shown in the equation (1) can be obtained.
It is also possible to reproduce data recorded at a recording density exceeding the limit of the above. Here, NA is the numerical aperture of the objective lens of the optical disk reproducing device, and λ is the wavelength of the laser beam used by the optical disk reproducing device. fs = 2NA / λ (1)

[0006]

By the way, when recording is repeatedly performed on an optical disk, the film quality of the recording layer of the optical disk changes, and even if the laser beam is irradiated with a predetermined recording power, data can be recorded well. May not be able to do so.

Further, even if test recording or the like is performed in advance in a predetermined area of the optical disk to optimize the recording power of the laser beam,
In the recording area on the optical disk, an area where the number of times of recording of data is large and an area where the number of times of recording are small are mixed. Since the sectors are mixed, for example, even if the power of the laser beam is appropriate for the sector with a small number of recordings, it may not be appropriate for the sector with a large number of recordings. It is difficult to set the recording power of the laser beam so as to be appropriate.

In view of the foregoing, an object of the present invention is to provide a recording power setting method and an optical disk apparatus capable of stably recording data repeatedly.

[0009]

According to the recording power setting method of the present invention, a specific pattern data is recorded on an optical disk using a light beam as a first recording power in an optical disk for recording and reproducing data in a predetermined recording unit. In addition, an optimum first reproduction power is detected based on a reproduction signal obtained by reproducing the first specific pattern data, and an optimum first reproduction power is detected based on a reproduction signal obtained by reproducing data written for each recording unit. The second reproduction power is detected, a correction value is obtained for each recording unit from the first reproduction power and the second reproduction power, and when recording data, the correction value obtained for each recording unit is used. This is for correcting the first recording power.

[0010] The optical disc apparatus further comprises a power control means for controlling the power of a light beam applied to the optical disc, a data recording means for recording data on the optical disc in a predetermined recording unit using the light beam, and a data recording means for utilizing the light beam. A data reproducing means for reproducing data recorded on the optical disc in a predetermined recording unit to obtain a reproduction signal; a pattern data generating means for generating specific pattern data; and a reproduction signal obtained by reproducing the data by the data reproducing means. A reproducing power detecting means for detecting an optimal reproducing power of the light beam based on the power beam; a power controlling means; a data recording means; a data reproducing means; a pattern data generating means; In the control means, the light beam is transmitted to the first
And the specific pattern data is recorded on the optical disk, and the recorded specific pattern data is reproduced to detect an optimum first reproduction power, and the data written for each predetermined recording unit of the optical disk is recorded. The optimum second reproduction power is detected based on a reproduction signal obtained by reproducing the data, a correction value is obtained for each recording unit from the first reproduction power and the second reproduction power, and the first value is used when data is recorded. Is corrected using the correction value.

In the present invention, the optical disk is irradiated with a light beam at the first recording power, and, for example, 2T pattern data and 4T pattern data having an inversion interval longer than the 2T pattern data are recorded. A first reproduction power capable of optimally reproducing the recorded pattern data is detected, and a VFO, for example, a repetitive pattern data for data reading written for each recording unit.
A second reproduction power capable of optimally reproducing data is detected. A correction value is obtained for each recording unit from the first reproduction power and the second reproduction power. At the time of data recording, the first recording power is corrected using the correction value obtained for each recording unit, and data recording is performed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an optical disk device 10 in which M
An SR type optical disk 11 is used.

The optical disk drive 10 includes a spindle motor 12 for rotating the optical disk 11, a frequency generator 13 for obtaining a frequency signal SFG as rotation information of the spindle motor 12, and a drive for driving the spindle motor 12. And a motor driver 14. The frequency signal SFG output from the frequency generator 13 is supplied to a servo controller 30 described later. The rotation of the spindle motor 12 is controlled by the servo controller 30 via the motor driver 14 so that the optical disk 1
1 is rotated at a predetermined speed.

FIG. 2 schematically shows the recordable area of the optical disk 11, and the outermost area is a test track area ARt. This test track area ARt
Is an area for performing test recording and test reproduction in order to perform appropriate recording and reproduction on the optical disc.

A control track area ARc is provided on the inner peripheral side following the test track area ARt, and control data such as optimum resolution data K0 is written in the control track area ARc in advance. The inner side of the control track area ARc is a user area ARu in which recording data is written by the user.

Here, the optimum resolution data K0 will be described with reference to FIGS. Consider a case in which, for example, 2T pattern data in which “00” and “11” alternately continue and 4T pattern data in which “0000” and “1111” alternately continue are written on the optical disc 11. In this case, when the power (reproduction power) of the light beam (laser light) applied to the optical disk 11 at the time of reproduction changes, the amplitude AM2t of the reproduction signal obtained by reproducing the 2T pattern data and the 4T pattern data are reproduced. The amplitude AM4t of the reproduced signal thus obtained changes as shown in FIG. 3A, and the amplitude ratio AM2t / AM4t changes as shown in FIG. 3B. In addition, the error rate of the read data of the optical disk 11 changes as shown in FIG. 3C according to the change of the reproduction power, and the error rate of the read data becomes the lowest at the reproduction power P1. The amplitude ratio AM2t / AM4t corresponding to the reproduction power P1 at which the error rate becomes the lowest is the optimum resolution data K0. The optimum reproduction power can be detected not only by the amplitude ratio AM2t / AM4t, but also by the inclination of the reproduction signal, for example, at a zero cross point, or the saturation signal level of the reproduction signal.

As shown in FIG. 1, the optical disk device 10 includes a magnetic head 21 for generating an external magnetic field, and a magnetic head driver 22 for controlling the generation of a magnetic field of the magnetic head 21.
And an optical head 25 including a semiconductor laser, an objective lens, a photodetector, and the like, and a laser driver 26 for controlling light emission of the semiconductor laser of the optical head 25. The magnetic head 21 and the optical head 25 are
Are arranged to face each other.

The magnetic head driver 22 is supplied with a recording signal DW from an encoder 64 to be described later or specific pattern data PTD from a pattern data generator 55,
A magnetic head drive signal MD is generated based on the recording signal DW or the specific pattern data PTD. The magnetic head drive signal MD is supplied to the magnetic head 21 and the magnetic head 21 generates a magnetic field.

The laser driver 26 is supplied with a pulse signal PW from a write pulse generation unit 56, which will be described later, and a laser power control signal Lpc from a power setting unit 53. The laser power control signal Lpc or the laser power control A laser drive signal LD for driving a semiconductor laser is generated based on the signal Lpc and the pulse signal PW.
The laser drive signal LD is supplied to the semiconductor laser of the optical head 25 to control the power of the laser light.

At the time of data reading (at the time of reproduction), the optical disk 11 is controlled based on the laser power control signal Lpc.
The power of the laser beam irradiated on the optical disk 11 is set to the reproduction power, and the data recorded on the optical disk 11 is reproduced.

At the time of data writing (at the time of recording),
Based on the laser power control signal Lpc and the pulse signal PW,
The power of the laser beam irradiated on the optical disk 11 is set to the recording power, and the pulse is irradiated in synchronization with the pulse signal PW.
The recording signal DW generated based on wt is supplied to the magnetic head driver 22, and the magnetic head 21 generates a magnetic field corresponding to the recording signal DW. For this reason, the magnetic head 21
The recording data Dwt is magneto-optically recorded in the user area ARu of the optical disk 11 by the magnetic field generated in step (1) and the laser beam emitted from the optical head 25. When the specific pattern data PTD is supplied from the pattern data generation unit 55 to the magnetic head driver 22, the test track area Art of the optical disc 11 is generated by the magnetic field based on the specific pattern data PTD and the laser beam from the optical head 25.
The specific pattern data PTD is magneto-optically recorded.

The optical disk device 10 has a CPU (central
and a servo controller 30 having a processing unit. The servo controller 30 is supplied with a focus error signal Sfe and a tracking error signal Ste generated from the optical head 25 by a conventionally known method. The servo controller 30 generates a focus drive signal Sfd and a tracking drive signal Std based on the focus error signal Sfe and the tracking error signal Ste, and supplies them to the optical head 25 to perform tracking and focus servo of the optical head 25. Under the control of the system controller 60, a sled motor (not shown) is driven to control the movement of the optical head 25 in the radial direction.

The reproduction signal Smo of the optical disk 11 output from the optical head 25 is supplied to an equalizer section 41. The equalizer section 41 adjusts the waveform by compensating the frequency characteristics of the reproduced signal Smo based on the high-frequency component EH supplied from the band dividing section 52 described later so that the resolution approaches the optimum resolution. The reproduced signal Smo processed by the equalizer 41 is supplied to the A / D converter 42 and the band divider 52 as a reproduced signal Sme.

The A / D converter 42 is supplied with a servo clock signal SCK from the PLL unit 43. Based on the servo clock signal SCK, the reproduction signal Sme is sampled and converted into a digital level data signal DL. . This level data signal DL is supplied to the amplitude memory unit 45 and the decoder 46.

In the PLL section 43, the level data signal DL
Is generated, and the servo clock signal SCK is frequency-divided to generate the data clock signal DCK. The generated servo clock signal SCK is supplied to the A / D converter 42 as described above, and the data clock signal DCK is supplied to the write pulse generator 56.

The amplitude memory section 45 stores the supplied level data signal DL. The decoder 46 decodes the supplied level data signal DL and generates a specific data detection flag signal FG from the decoding result. The specific data detection flag signal FG is a signal for detecting specific data from the level data signal DL, and is supplied to the resolution detection unit 47. further,
Reproduction data D obtained by decoding by the decoder 46
rd is output via the interface unit 62.

In the resolution detecting section 47, an amplitude memory section 45
, The level data signal DL sequentially stored is read to detect the resolution. Here, the resolution detection unit 47 reads out the level data signal DL of the 2T pattern and the level data signal DL of the 4T pattern based on the specific data detection flag signal FG supplied from the decoder 46, for example. 2T pattern level data signal D
The resolution data K is generated by calculating the ratio between the level difference of L and the level difference of the level data signal DL of the 4T pattern. The resolution data K obtained by the resolution detection section 47 is
0 is supplied.

The comparing section 50 compares the resolution data K detected by the resolution detecting section 47 with the optimum resolution data K0 stored in the optimum resolution storage section 51, generates a signal DK indicating the comparison result, and generates a signal DK. It is supplied to the dividing unit 52.

In the band dividing section 52, based on the signal DK,
If the resolution data K is not within a predetermined error range (for example, about 1%) with respect to the optimum resolution data K0, the frequency band of the reproduced signal Sme is decomposed into a high-frequency component EH and a DC and low-frequency component EL. The component EH is supplied to the equalizer unit 41, and the component EL is supplied to the power setting unit 53.

The power setting section 53 is supplied with a power monitor signal PM indicating the power of the laser beam from the optical head 25. The power setting unit 53 has a power setting signal PC for setting the power of the laser beam during data recording.
w and a power setting storage unit 54 storing a power setting signal PCr for setting the power of the laser beam during data reproduction.
Is connected. Here, at the time of data recording and data reproduction, the laser beam is controlled to a predetermined power level based on the power setting signals PCw and PCr from the power setting storage unit 54 and the power monitor signal PM from the optical head 25. A laser power control signal Lpc is generated and supplied to the laser driver 26. When the DC and low frequency components EL are supplied to the power setting unit 53, the laser power control signal Lp is set so that the resolution data K becomes equal to the optimum resolution data K0 by the components EL.
c is controlled to correct the power of the laser beam.

In the write pulse generator 56, the PLL 43
Generates a pulse signal PW that is synchronized with the data clock signal DCK supplied from. The pulse signal PW is supplied to the laser driver 26, and the power of the laser beam output from the semiconductor laser of the optical head 25 is controlled as described above.

The recording data Dwt supplied via the interface 62 is supplied to an encoder 64. The encoder 64 encodes the recording data Dwt to generate a recording signal DW. The recording signal DW is supplied to the magnetic head driver 22 so that the magnetic head 2
1 generates a magnetic field corresponding to the recording signal DW, and the recording data Dwt is magneto-optically recorded on the optical disk 11. Also,
The magnetic head driver 22 includes a pattern data generator 5
5 is connected.

In the pattern data generator 55, for example,
Specific pattern data PTD composed of T pattern data and 4T pattern data is generated. The specific pattern data PTD is supplied to the magnetic head driver 22.

The system controller 60 is configured using a CPU, and generates a control signal CT according to the operation of the operation unit 65 connected to the system controller 60. The generated control signal CT is supplied to each unit to control the entire system.

Next, the recording operation of the optical disk device 10 will be described with reference to the flowchart of FIG. Step ST1
When the optical disk 11 is mounted on the optical disk apparatus 10, the magnetic head 21 and the optical head 25 are moved by the servo controller 30 to the control track area AR.
A seek operation is performed at a position corresponding to c to read out optimal resolution data and the like. In addition, the read optimal resolution data K
0 is stored in the optimum resolution storage unit 51.

In step ST2, an optimum recording power is set. In this case, for example, Japanese Patent Application No. 9-11840, filed by the applicant of the present invention (filed on Jan. 8, 1997)
As described in detail above, writing and reading of pattern data in which “0” continues or 2T pattern data in which “00” and “11” alternate alternately are performed as appropriate with respect to the test track area ARt. The amplitude of the reproduced signal of the 2T pattern data is detected, and the optimum recording power is set based on the detected amplitude. Further, a power setting signal PCw in which the power of the laser beam becomes the optimum recording power is stored in the power setting storage unit 54.

In step ST3, the specific pattern data PTD is written to the test track area ARt with the optimum recording power. For example, specific pattern data PTD including 2T pattern data in which “00” and “11” alternately and 4T pattern data in which “0000” and “1111” alternately are generated by the pattern data generating unit 55, It is supplied to the magnetic head driver 22. In this case, the power (recording power) of the laser beam applied to the optical disk 11 is stored in the power setting storage unit 5.
Based on the power setting signal PCw stored in step No. 4, the recording power is set to the optimum recording power set in step ST2.

At step ST4, the specific pattern data written in the test track area ARt is reproduced, and based on the reproduced signal Smo at this time, the ratio of the level difference between the level data signals of the 2T pattern data and the 4T pattern data, that is, The amplitude ratio is calculated by the resolution detector 47. Further, the reproduction power is adjusted so that the resolution data K, which is the amplitude ratio, is within a predetermined error range (for example, about 1%) with respect to the optimum resolution data K0 stored in the optimum resolution storage unit 51. Do. here,
The reproduction power when the resolution is within a predetermined error range is set as the optimum reproduction power. Further, a power setting signal PCr in which the power of the laser beam becomes the optimum reproducing power is stored in the power setting storage unit 54.

In step ST5, the sensitivity is monitored by reproducing the recording unit of the user area ARu for recording data, for example, the VFO written at the head of the sector. In this sensitivity monitor, the ratio of the amplitude of the signal of the short mark length portion to the amplitude of the signal of the long mark length portion of the reproduced signal obtained by reproducing the VFO, the inclination of the reproduced signal at the zero cross point, or The ratio of the saturation level on the high level side to the saturation level on the low level side of the reproduction signal is used. By monitoring this sensitivity, the reproduction power at which the resolution is optimal for each recording unit is determined.

In step ST6, the ratio between the optimum reproduction power set in step ST4 and the reproduction power determined for each recording unit of the user area ARu in step ST5 is calculated.

In step ST7, the optimum recording power set in step ST2 is corrected using the ratio obtained in step ST6. By correcting the optimum recording power in this way, the recording power can be optimized for each recording unit of the user area ARu. Step S
At T6, a power difference between the optimum reproduction power set at step ST4 and the reproduction power determined at step ST5 is determined, and step S5 is performed based on the power difference.
The optimum recording power set at T2 may be corrected to optimize the recording power for each recording unit.

In step ST8, the optical head 25 irradiates a laser beam to the optical disk 11 with the recording power corrected in accordance with each recording unit, and applies a magnetic field based on the recording data Dwt from the magnetic head 21 to read the data. Start recording. Here, since the recording power of the laser beam is corrected and optimized for each recording unit, the recording data Dwt can be optimally magneto-optically recorded in the user area ARu of the optical disk 11.

As described above, according to the above-described embodiment,
Even if the sensitivity is different for each recording unit by repeatedly recording and reproducing data, the recording power is corrected and optimized for each recording unit, so that data can be stably recorded.

In the above embodiment, the 2T pattern data and 4T pattern data are stored in the test track area ARt.
Although the reproduction power set value is determined by writing and reading specific pattern data composed of patterns, these specific pattern data are merely examples and the present invention is not limited to this. Further, if a temperature sensor for detecting the temperature of the optical disk 11 is provided in the vicinity of the optical disk 11 to be loaded, and the recording power is corrected in accordance with the temperature detected by the temperature sensor, it is more stable. Data can be recorded. Further, the invention of the present application provides an optical disc 1 of the MSR system.
It is needless to say that the present invention is not limited to the optical disk device 10 using the optical disk drive 1 but can be similarly applied to other optical disk devices as long as the resolution changes with the reproduction power.

[0045]

According to the present invention, the first pattern data capable of optimally reproducing the specific pattern data recorded at the first recording power.
And the second reproduction power capable of optimally reproducing the data written for each recording unit is detected, and the second reproduction power is obtained for each recording unit from the first reproduction power and the second reproduction power. The first recording power of the light beam at the time of data recording is corrected using the corrected value. For this reason, even if the sensitivity differs for each recording unit due to repeated recording, the recording power of the light beam is controlled according to each recording unit, so that data recording can be repeatedly performed stably. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an optical disk device according to the present invention.

FIG. 2 is a diagram illustrating a configuration of an optical disc.

FIG. 3 is a diagram for explaining optimum resolution data and the like.

FIG. 4 is a flowchart for explaining setting of recording power.

FIG. 5 is a diagram for explaining a reproduction principle of the CAD system.

[Explanation of symbols]

11 ... optical disk, 21 ... magnetic head, 22.
..Magnetic head drivers, 25 ... optical heads, 26
... Laser driver, 41 ... Equalizer part, 42
... Conversion unit, 43 ... PLL unit, 45 ... Amplitude memory unit, 46 ... Decoder, 47 ... Resolution detection unit, 50 ... Comparison unit, 51 ... Optimal resolution storage unit ,
52: band division unit, 53: power setting unit, 54
... power setting storage unit, 55 ... pattern data generation unit, 56 ... write pulse generation unit, 60 ... system controller, 62 ... interface, 64 ...
・ Encoder

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Claims (6)

[Claims] 1. An optical disk for recording / reproducing data in a predetermined recording unit, wherein a specific pattern data is recorded on the optical disk using a light beam as a first recording power, and the first specific pattern data is reproduced. Detecting an optimum first reproduction power based on the obtained reproduction signal; detecting an optimum second reproduction power based on a reproduction signal obtained by reproducing the data written for each recording unit; A correction value for each recording unit from the reproduction power of 1 and the second reproduction power, and when recording data, the first recording power is calculated using the correction value obtained for each recording unit. A recording power setting method characterized by correcting. 2. The recording power setting method according to claim 1, wherein the specific pattern data includes first pattern data and second pattern data having a longer inversion interval than the first pattern data. . 3. The recording power setting method according to claim 1, wherein the data written for each recording unit is repetitive pattern data for data reading. 4. The recording power setting method according to claim 1, wherein the first and second reproduction powers are detected based on an amplitude ratio, a slope, or a signal level of the reproduction signal. 5. A power control unit for controlling a power of a light beam applied to an optical disk, a data recording unit for recording data on the optical disk in a predetermined recording unit using the light beam, and using the light beam. Data reproducing means for reproducing the data recorded on the optical disc in the predetermined recording unit to obtain a reproduction signal; pattern data generating means for generating specific pattern data; and reproducing by the data reproducing means. Reproducing power detecting means for detecting an optimum reproducing power of the light beam based on a reproducing signal; operation of the power control means, the data recording means, the data reproducing means, the pattern data generating means, and the reproducing power detecting means. An operation control unit for controlling, wherein the operation control unit sets the light beam to a first recording power and Specific pattern data is recorded on the optical disk, the recorded specific pattern data is reproduced to detect an optimal first reproduction power, and data written for each predetermined recording unit of the optical disk is reproduced. The optimum second reproduction power is detected based on the reproduction signal obtained by the above, and a correction value is obtained for each recording unit from the first reproduction power and the second reproduction power. 1. An optical disk device, wherein the recording power of 1 is corrected using the correction value. 6. The pattern data generating means according to claim 1, wherein
6. The optical disk apparatus according to claim 5, wherein the specific pattern data including the first pattern data and the second pattern data having a longer inversion interval than the first pattern data is generated.