JPH10199063A - Device and method for data recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily set an optimum laser light beam output power for recording, by utilizing all of or any one of the laser power values corresponding to erase residual amount, cross talk, and cross erase. SOLUTION: An optimum laser power amount Pideal is set based on the laser power amounts POW, PCRS and PERA where POW is the amount of the laser power, in which the recorded data erasing residual amount becomes a prescribed percentage or less with respect to a beforehand set reference value, PCRS is the amount of the laser power, in which the amount of the data reproduced as cross talk becomes a prescribed percentage or less with respect to a beforehand set reference value and PERA is the amount of the laser power, in which the residual amount of the data to be erased by cross erase becomes a prescribed percentage or less with respect to a beforehand set reference value. A controller 6 sets the value so that each of the amount of the data erasing residual by overwriting, the amount of cross talk and the amount of cross erase satisfies the optimum condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording apparatus and a data recording method for a recording medium.

[0002]

2. Description of the Related Art Disk-shaped recording media such as optical disks and magneto-optical disks have become widespread as portable media. In particular, a data rewritable magneto-optical disk (MO disk) is suitable as a medium for computer use.

[0003] As a recording system adopted in a recording / reproducing apparatus corresponding to the above-mentioned magneto-optical disk, an optical modulation system and a magnetic field modulation system are mainly known. The light modulation method is a method in which a laser beam applied to a recording surface of a disk is modulated by recording data in a state where an external magnetic field is applied in a certain direction perpendicular to the recording surface of the disk. In the magnetic field modulation method, a magnetic field modulated by recording data is applied from a magnetic head to a recording surface of a disk, and a constant amount of laser light is continuously irradiated (simple magnetic field modulation method), or pulse light emission is synchronized with recording data. (Laser strobe magnetic field modulation method).
As a result, a magnetic field of N or S pole according to the recording data is applied to the recording surface of the disk, and data as magnetic field information is recorded. It is known that in the magnetic field modulation method as described above, in principle, the asymmetry of the recording pit is small, so that the read data level can be severe. For example, the multi-value detection method in the partial response is used. It is also effective when adopting.

[0004]

By the way, in order to perform proper data recording on a magneto-optical disk, it is necessary that the output power of a laser beam applied to the disk during recording be appropriately set. Therefore, it is necessary to set an appropriate laser beam output power at the time of recording. For example, in the optical modulation method, the asymmetry state, the appearance of the second harmonic, the resolution, etc. change in response to the change in the laser light output power during recording. The optimum laser light output power at the time of recording is set based on the asymmetry, the second harmonic, the resolution, and the like detected by reproducing the track on which this data is recorded.

On the other hand, in the magnetic field modulation system, it is known that, in principle, changes in the asymmetry, second harmonic, and resolution have little dependence on changes in laser beam output power during recording. Therefore, in the magnetic field modulation method, when viewed from the viewpoint of the asymmetry, the second harmonic, and the resolution, the laser beam output power at the time of recording is
It can be seen that strictness is not required when compared with the optical modulation method. However, in addition to the remaining erasure amount of past data that was overwritten and erased when data was overwritten, the extent to which data on adjacent tracks was cross-talked when a certain track was played, and the data recorded on a certain track When the data is applied, the extent of the so-called cross-erase, in which the data already applied to the adjacent track is erased by the application of the data to the adjacent track, depends on the laser beam output power at the time of recording. . If such conditions are not appropriate, accurate data reproduction may be hindered in some cases. Therefore, even in the magnetic field modulation method, the remaining erasure amount of the overwritten data, crosstalk, cross erase, etc. In consideration of this, it is necessary to appropriately set the laser beam output power at the time of recording. However, as described above, in the magnetic field modulation method, the characteristics such as asymmetry, second harmonic, and resolution do not depend on the laser light output power. It is difficult to adopt the method

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for easily setting an optimum laser beam output power at the time of recording even in a magnetic field modulation system so as to ensure the reliability of reproduced data. The purpose is to do.

[0007] Therefore, a recording magnetic field modulated by recording data is applied to a recording medium as a recording magnetic field, and the recording medium is irradiated with laser light having a required laser output power to record data on the recording medium. As a data recording device that can perform data overwriting when a new data is overwritten on a track on which data has already been recorded and the remaining erasure amount of the already recorded data falls below a predetermined value. The first recording laser power detected as described above and the leakage reproduction amount of the data recorded on the specific track at the time of reproduction on the specific track become equal to or more than a predetermined value. The second recording laser power to be recorded on a track adjacent to the specific track for data already recorded on the specific track. The recording laser power is set based on all or a part of the third recording laser power detected corresponding to the case where the remaining amount of erasure by the operation becomes a predetermined ratio or less with respect to a predetermined reference value. And a recording laser power setting means capable of setting the recording laser power.

In addition, a recording magnetic field modulated by recording data is applied to a recording medium as a recording magnetic field, and the recording medium is irradiated with a laser beam having a required laser output power to record data on the recording medium. As a data recording method that can be performed, it corresponds to a case where the erasing remaining amount of the already recorded data when a new data is overwritten on a track on which the data is already recorded becomes a predetermined value or less. The first recording laser power detected and the second detection detected when the leakage reproduction amount of the data recorded on the specific track at the time of reproduction on the specific track becomes a predetermined value or more. And the recording operation of the data already recorded on a specific track on a track adjacent to the specific track. A detection procedure for detecting all or a part of the third recording laser power detected when the remaining erasing amount is equal to or less than a predetermined ratio with respect to a predetermined reference value; A setting procedure for setting a recording laser power for performing data recording on a recording medium based on the result, and a recording procedure for recording data on the recording medium based on the recording laser power set by the setting procedure Is configured to be executed.

[0009] According to the above configuration, based on the remaining amount of data to be erased by overwriting, not based on conditions such as asymmetry, second harmonic, and resolution detected by reproducing recorded data. A first laser output power detected, a second laser output power detected based on a crosstalk amount of data recorded on a specific track at the time of reproducing a track adjacent to the specific track, and a specific laser output power. For all or a part of the third laser output power of data already recorded on the track, which is detected based on, for example, the remaining amount of erasing (cross erase amount) by the recording operation on the track adjacent to the specific track. Based on the information, it is possible to set the laser beam output power that is optimized during recording.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, as a preferred embodiment of the present invention, a recording / reproducing apparatus using a magneto-optical disk as a recording medium will be described as an example. The following description will be made in the following order. <1. Configuration of recording / reproducing device><2. Laser power value setting of this embodiment> (a. Overall processing operation) (b. Laser power value setting process corresponding to overwrite erasure amount) (c. Laser power value setting process corresponding to crosstalk) (d. Cross erase compatible) (Laser power value setting process) (e. Optimal laser power value setting process) (f. Laser power value setting process as another embodiment)

<1. Configuration of Recording / Reproducing Apparatus> FIG. 1 is a block diagram of the recording / reproducing apparatus. The magneto-optical disk 1 shown in FIG. 1 is driven to rotate at a predetermined rotation speed by a spindle motor 2. The rotation speed servo control of the spindle motor 2 is performed by the spindle control unit 3. For example, the spindle control unit 3 detects the rotation speed of the spindle motor 2 based on an FG pulse (frequency signal synchronized with the rotation speed) from the spindle motor 2 and the like, and supplies the reference speed information SK from the controller 6 and the reference speed information SK. By comparing the rotation speed of the spindle motor 2 with the rotation speed of the spindle motor 2 and performing acceleration / deceleration of the spindle motor 2 based on the error information, a disk rotation operation at a required rotation speed is realized.

For the optical disc 1 being rotated,
Laser light from the optical pickup 4 is irradiated. The optical pickup 4 includes, for example, a laser light source 4c such as a laser diode or a laser coupler, an optical system 4e such as various lenses or a beam splitter, an objective lens 4a serving as an output end of a laser beam, and a detector 4d detecting reflected light from a disk. And a biaxial mechanism 4b for holding the objective lens 4a movably in the tracking direction and the focus direction. On / off of the laser output from the laser light source 4c and the output level in the optical pickup 4 are controlled by the laser control unit 5.

The recording / reproducing apparatus is connected to a host computer 90 by an interface section 19, and the data recording / reproducing operation is executed by the controller 6 receiving a recording request and a reproducing request from the host computer 90. Will be. During recording, data to be recorded is supplied from the host computer 90 together with the recording request. The recording data D _REC is supplied from the interface unit 19 to the encoder 25, where necessary encoding processing is performed.

The recording / reproducing apparatus of the present embodiment employs a magnetic field modulation method as a recording method. The magnetic field modulation method includes a simple magnetic field modulation method in which a magnetic field modulated based on recording data is applied to a disk recording surface and a laser beam is continuously irradiated with a constant light amount. There is a laser strobe magnetic field modulation system in which a magnetic field modulated based on recording data is applied and a laser beam is emitted in a pulsed manner.

When the above-described magnetic field modulation method is adopted, the controller 6 controls the laser control unit 5 during recording.
Is controlled so that the laser output from the laser light source 4c is continuously emitted or pulsed. The recording data encoded by the encoder 25 is supplied to a magnetic head driver 26, and the magnetic head driver 26
Applies an N or S magnetic field from the magnetic head 27 according to the recording data. As a result, the recording data is recorded on the disk 1 as magnetic field information.

The data reading position of the optical pickup 4 can be moved in the radial direction. Although not specifically shown, a sled mechanism is provided to allow the entire optical pickup 4 to move in the radial direction of the disc, thereby performing a large movement of the reading position, and moving the objective lens 4a to the biaxial mechanism 4b. Is moved in the radial direction of the disk, that is, the reading position is moved slightly by the tracking servo operation.

Note that, instead of the sled mechanism for moving the optical pickup 4, a mechanism for sliding the disk 1 together with the spindle motor 2 may be provided. Further, the focus control of the laser spot LSP is performed by moving the objective lens 4a toward and away from the disk 1 by the biaxial mechanism 4b.

As the detector 4d of the optical pickup 4, for example, a four-segment detector having a four-segment light receiving area, a detector for detecting magnetic field data for each polarization component by the magnetic Kerr effect, and obtaining an RF signal as magneto-optical data, etc. Is provided.

From each light receiving area of the detector 4d,
A current signal S1 corresponding to the amount of received light is output, and these are supplied to the I / V conversion matrix amplifier 7. The I / V conversion matrix amplifier 7 performs current-voltage conversion on the received light amount signal S1, and generates necessary signals such as an RF signal, a push-pull signal, and a focus error signal FE by performing arithmetic processing on signals from the respective light receiving regions. I do.

A focus error signal FE serving as focus state error information is supplied to the servo controller 8. The servo controller 8 is equipped with a focus phase compensation circuit, a focus driver, and the like as a processing unit of a focus system, and generates a focus drive signal based on the focus error signal FE and applies the signal to the focus coil of the two-axis mechanism 4b. As a result, a focus servo system for converging the objective lens 4a to the just focus point is formed.

From the I / V conversion matrix amplifier 7, an RF signal used for generating the servo clock SCK and the data clock DCK is output as a signal S2. The signal S2 is obtained by removing the low frequency fluctuation of the RF signal by the clamp circuit 9 and digitizing the signal S by the A / D converter 10.
It becomes 3. This signal S3 is supplied to the controller 6, the PLL circuit 11, and the tracking error generator 16.

The PLL circuit 11 generates the servo clock SCK synchronized with the RF signal by controlling the oscillation frequency of the internal oscillator based on the phase error between the signal S3 and the oscillation output and performing a predetermined frequency division process. . This servo clock SCK is used as a sampling clock in the A / D converter 10 and is supplied to the timing controller 17. Further, the PLL circuit 11 divides the frequency of the servo clock SCK to generate a data clock DCK, and the timing controller 17 and the laser controller 5
Supplied to It is used as a sampling clock in the A / D converter 13.

The timing controller 17 generates a necessary timing signal for each section based on the servo clock SCK and the data clock DCK. For example, a sampling timing Ps for extracting a servo pit for a three-phase tracking operation, a synchronization timing DSY for a decoding operation in the data detection unit 14, and the like are generated.

The tracking error signal T by the so-called three-phase tracking control is generated by the PLL circuit 11, the timing controller 17, and the tracking error generator 16.
E is generated and will be described to the servo controller 8.

From the I / V conversion matrix amplifier 7, an RF signal and a push-pull signal used for data extraction are output as a signal S4. This signal S4 becomes a signal S5 digitized by the A / D converter 13 after the low frequency fluctuation of the RF signal is removed by the clamp circuit 12. Signal S4
Is also branched and supplied to the amplitude detection circuit 30. The amplitude detection circuit 30 outputs information on the detected amplitude level to the controller 6. In the present embodiment, the amplitude detection circuit 30 detects the amplitude level of the signal S4 obtained when predetermined test pattern data is read during setting processing of a laser power value during recording, which will be described later. Used.

The signal S5 is supplied to a data detector (ie, a decoder) 14. In the data detector 14, the timing controller 17 performs data decoding processing based on the synchronization timing DSY generated based on the data clock DCK, and obtains reproduction data D _PB . For example, a waveform equalization process, a demodulation process for a modulation process adopted as a recording format, an error correction process, and the like are performed, and the data is encoded as reproduction data D _PB . The reproduction data D _PB is supplied to the host computer 90 via the interface unit 19.

<2. Laser Power Value Setting of the Present Embodiment> (a. Overall Processing Operation) Hereinafter, setting of the laser power value at the time of recording in the recording / reproducing apparatus of the present embodiment will be described. An overall processing operation for setting a value will be described with reference to FIG. The setting of the laser power value at the time of recording is performed in a state where the disk 1 is loaded in advance.

FIG. 2 is a flowchart showing the overall processing operation for setting the laser power value during recording. This process is executed by the controller 6 (see FIG. 1). In the routine shown in FIG.
At 101, the mode shifts to a laser power setting mode for setting a laser power value at the time of recording. The condition for shifting to the laser power setting mode may be, for example, that the recording and reproducing apparatus of the present embodiment shifts to the laser power setting mode every time the disc 1 is loaded. Alternatively, the recording / reproducing apparatus of the present embodiment may request the setting of the laser power every predetermined period. Subsequent step S10
In step 2, a process for detecting the laser power value _POW corresponding to the overwrite erasure amount is executed. In this embodiment, the overwrite-deletion amount-corresponding laser power value P _OW is defined as the data recorded on a track on which data has already been recorded, when the data is overwritten by deleting this recorded data. The laser power value indicates when the erased remaining amount of the data which has been completed becomes equal to or less than a predetermined ratio with respect to a preset reference value, which will be described later.

In the following step S103, a process for detecting the crosstalk-corresponding laser power value _PCRS is executed. For example, in a so-called crosstalk phenomenon in which data recorded on a certain track is reproduced so as to leak when reproducing an adjacent track, the leakage amount of reproduced data obtained as crosstalk increases as the laser power increases. However, the crosstalk-corresponding laser power value _PCRS here refers to a laser power value indicating that the amount of data reproduced as the crosstalk has become a predetermined ratio or more with respect to a preset reference value. This will be described later.

In the following step S104, a process for detecting the cross erase corresponding laser power value P _ERA is executed. When data is recorded on a certain track, crosstalk occurs on an adjacent track as described above. If data has already been recorded on this adjacent track, this recorded data is The data recorded as crosstalk is overwritten and erased to some extent. In this embodiment, such a phenomenon is referred to as cross-erase. The laser power value P _ERA corresponding to the cross-erase indicates that the remaining amount of data erased by the cross-erase is equal to or less than a predetermined ratio with respect to a preset reference value. The laser power value indicates the time when the power has become, which will also be described later.

In step S105, based on the laser power values P _OW , P _CRS , and P _ERA detected in steps S102, S103, and S104, an optimum laser power value P _ideal which is optimized during recording is set. Execute the process for The specific method of setting the optimum laser power value P _ideal will be described later after the detection processing of the laser power values P _OW , P _CRS , and P _ERA is described.

(B. Laser Power Value Setting Process Corresponding to Overwrite Erasing Amount) Hereinafter, the process of detecting the laser power values P _OW , P _CRS , and P _ERA will be described. First, the respective laser power values P _OW , P _CRS , The disk 1 and the test data format used when detecting P _ERA will be described with reference to FIGS. FIG. 8 schematically shows a recordable area of the disk 1 which can be used for setting a laser power value according to the present embodiment. As shown in FIG. _AT . The test area _AT is an area provided for the recording / reproducing apparatus to perform test recording / reproduction of data required for performing appropriate recording / reproduction on a disk. The setting of the laser power value at the time of recording in the present embodiment is also performed by using the test area _AT . Here, among the tracks forming the test area _AT , predetermined tracks i−1, It is assumed that tracks i and i + 1 are used. A control area A _CNT in which data to be used for various recording / reproduction controls is provided in an inner area subsequent to the test area _AT, and further inside, a control area A _CNT is provided. A user area A _U in which data to be used is recorded is provided.

The laser power values P _OW , P _CRS , P
FIG. 9 shows an example of a test pattern of test data recorded in the test area _AT when _ERA is detected. In the present embodiment, the test pattern of the test data is
Data of two different patterns, “2T pattern” shown in FIG. 9A and “00 pattern” shown in FIG. 9B are used. The “2T pattern” is, for example, [00
..] Is a pattern in which [00] and [11] are alternated, and the “00 pattern” is a pattern in which [0] is continuous such as [0000000000000.

The flowchart of FIG. 3 shows the process of detecting the laser power value _POW corresponding to the overwrite erasure amount, which is the process of step S102 in FIG. In the routine shown in this figure, first the process of setting a predetermined initial value P ₀ for the laser power P at the time of recording in step S201 is performed.

In the following step S202, a control process for initializing a test track on the disk 1 is executed. The test track initialization here means
At least the process of recording 00 patterns on track i-1, track i, and track i + 1 in the test area described with reference to FIG. When the initialization of the test track is completed, the controller 6 proceeds to step S203 and records the 2T pattern on the i-th track.

In the next step S204, i
Control processing for reproducing the track is executed. Then, as processing of the subsequent step S205, the controller 6
Inputs the reproduced signal S4 of the 2T pattern reproduced from the i-track to the amplitude detector 30 (see FIG. 1), and executes control so that the amplitude is detected here. The amplitude level of the reproduced signal of the 2T pattern detected by the amplitude detector 30 is defined as V _2T , and the amplitude level corresponding to the initial power of the 2T pattern (the amplitude of the reproduced signal of the 2T pattern recorded by the initial laser power P). When the mean level) and V _2T0, processing is performed to set the amplitude level V _2T detected here as the initial power corresponding amplitude level V _2T0. This initial power corresponding amplitude level V _2TO is used as a reference value for subsequent detection.

[0037] In subsequent step S206, as a power sweep initialization process, a process for the the laser power value _{P P = P 0/2 ···} ( Equation 1). That is, the laser power value P is set to の of the initial laser power value P ₀ .

Then, the controller 6 proceeds to step S20.
As the process of step S207 following S6, the above P = P ₀
With the laser power value P indicated by / 2, a process of recording 00 patterns on the i-th track is performed. By executing this process, for the i track, the 00 pattern is overwritten and recorded on the 2T pattern previously recorded.

The controller 6 proceeds to the next step S208.
The control for reproducing the i-track is executed in. Then, in S209, the amplitude level V _2T of the 2T pattern obtained by reproducing the i-track is detected based on the detection output of the amplitude detection unit 30. That is, in step S209, the remaining erasure amount of the 2T pattern to be erased by the overwrite recording of the 00 pattern is set to 2T.
The detection is performed based on the amplitude level V _{2T of the} pattern.

In the following step S210, the amplitude level V _{2T of} the 2T pattern detected in step S209.
And the initial power-corresponding amplitude level V _2T0 set in step S205, for example, to determine whether or not V _2T <V _2T0 / 2 (Equation 2). That is, it is determined whether or not the ratio of the remaining data amount of the 2T pattern overwritten on the i-th track has decreased to a level where the above (Equation 2) holds. Also, in step S210, with respect to the current laser power value P, if a predetermined limit laser power value is Pth, it is determined whether or not P> Pth (Equation 3). This corresponds to the power sweep processing described below (step S21).
This is to determine whether or not the laser power value raised by 1) has reached a predetermined upper limit value. Then, if a positive result is obtained in step S210, the process proceeds to step S212. If a negative result is obtained, the process proceeds to step S211. explain.

In step S211, a power sweep process is performed on the laser power value P. In other words, if it is determined that the data amount of the 2T pattern overwritten on the i-th track is left more than that shown by (Equation 2), the laser power value P set so far is raised by a predetermined ratio. The processing is performed. Here, for example, the level is increased with respect to the laser power value P by an expression represented by P = P + 1/20 × P ₀ (Equation 4). That is, a new laser power value P is set by adding 1/20 of the initial laser power value P _{0 to} the laser power value P set up until now. After the processing of step S211 is completed, step S207
However, until a positive result is obtained in step S210, steps S207 to S207 are performed.
The processing of 211 is repeated.

Incidentally, for example, in steps S207 to S2
By repeating the processing of No. 11, the data of the 00 pattern is overwritten by the laser power value P gradually increased (power sweep) on the data of the 2T pattern previously recorded on the i-th track. At this time, the relationship between the amplitude level V _2T detected in step S209 and the laser power value P is, for example, as shown in FIG.
(A). The amplitude level V _2T of the 2T pattern data decreases according to the characteristics shown in the figure as the laser power value P increases, but in the present embodiment, the amplitude level V _{2T of the} 2T pattern data increases. Is the initial power-corresponding amplitude level V set in step S205.
The laser power value when a half or less of _2T0, so that the overwriting amount corresponding laser power value P _OW. Therefore, in step S210 described above, (Equation 2)
Is determined as to whether the current laser power value P corresponds to the laser power value _POW corresponding to the overwrite erasure amount.

If it is determined in step S210 that (Equation 2) holds, step S21 is executed.
In step 2, the current laser power value P is set as the laser power value _POW corresponding to the overwrite erasure amount. (Equation 2)
Even if a negative result is obtained for the establishment of (Equation 3)
If a positive result is obtained for the establishment of
Proceeding to 212, a process of setting the current laser power value P as a laser power value _POW corresponding to the overwrite erasure amount is performed. Accordingly, for example, if the laser power value P exceeds the laser power value enough to satisfy (Equation 2) for some reason and falls into a state where (Equation 2) does not hold, the laser power value P will remain unchanged. Abnormal rise is prevented.

(C. Processing for Setting Laser Power Value Corresponding to Crosstalk) The flowchart of FIG. 4 shows a processing operation for detecting the laser power value _PCRS corresponding to crosstalk, which is the processing of step S103 in FIG. Is equivalent to Note that in this figure, steps S301 to S3
Steps S201 to S05 shown in FIG.
Since the processing is the same as the processing up to 205, the description is omitted. That is, by the processing of steps S301 to S305, after the test track is initialized, the 2T pattern is recorded on the i-th track, and the amplitude level of the 2T pattern is set as the initial power-corresponding amplitude level _V2T0 .

In the following step S306, a process is performed for the laser power value P, for example, P = P ₀ + 0.1P ₀ ... In other words, the laser power value P is slightly increased from the initial value. Then, in the next step S307, the 00 pattern is recorded on the i-th track by the laser power level-up as described above. At this time, since the laser power is slightly increased from the initial value, the laser power is recorded on the i-track used at the time of detecting the laser power value _POW corresponding to the overwriting erasure remaining amount previously executed. The remaining data amount of the existing 2T pattern is set to be negligibly small so as not to affect the subsequent detection processing.

Subsequently, the controller 6 proceeds to step S30.
In step S8, a power sweep initialization process (the same process as step S206 in FIG. 3) is executed, and the process proceeds to step S3.
In step 09, the 2T pattern is recorded on track i-1 and track i + 1 based on the laser power value P set in step S308. As a result of the processing so far, all the tracks i−1, i, i + 1 are set to 0.
From the state where 0 pattern is recorded, 2T pattern data is overwritten on tracks i-1 and i + 1 adjacent to both sides of track i.

In the next step S310, the i track is reproduced, and in the following step S311, a process of detecting the amplitude level V _2T of the 2T pattern from the reproduced signal obtained by reading out the i track is performed. Here, the detection of the amplitude level V _2T of the 2T pattern in the i-th track means that, in step S309, the tracks i−1,
This is nothing but detecting the crosstalk amount of the 2T pattern data recorded in i + 1.

Here, FIG. 7B shows the laser power value at the time of recording in step S309 and the above-mentioned step S31.
1 shows the relationship with the amplitude level V _2T of the 2T pattern in the i-th track detected in FIG. Step S3
09, the laser power value when recording the 2T pattern on tracks i−1 and i + 1 increases,
The crosstalk amount of the data of the 2T pattern in the i-track increases.
The characteristic that the amplitude level V _2T of the T pattern rises as shown in the figure as the laser power value becomes higher is obtained. Then, in the present embodiment, step S3
11, the amplitude level V _2T of the 2T pattern in the i-track and the amplitude level V _{2T 0} corresponding to the initial power.
For example, the laser power value when V _2T > V _2T0 × 0.2 (Equation 6) holds is set as the crosstalk-corresponding laser power value P _CRS .

Therefore, in step S312, it is determined whether or not the above-mentioned (Equation 6) holds for the amplitude level V _2T of the 2T pattern detected in step S311. Alternatively, similarly to the case of step S210 in FIG. 3, it is determined whether or not (Equation 3) holds. If a negative result is obtained in step S312, the process advances to step S313 to execute a power sweep process (similar to step S211 in FIG. 3) for the laser power, and then return to step S309. You. Thus, until it is determined in step S312 that (Equation 6) or (Equation 3) is satisfied, recording of the 2T pattern on tracks i−1 and i + 1 by the laser power gradually increased by the power sweep processing, and i Detection processing of the amplitude level V _2T of the 2T pattern in the track is performed.

If it is determined in step S312 that (Equation 6) or (Equation 3) is satisfied, the process proceeds to step S314, where the current laser power value P
_Is set as the laser power value _PCRS corresponding to the crosstalk.

(D. Cross Erase Corresponding Laser Power Value Setting Processing) The flowchart of FIG. 4 shows a processing operation for detecting the cross erase compatible laser power value P _ERA , which is performed in step S104 in FIG. It corresponds to processing. Note that, in FIG.
The processing from 1 to S406 is performed in step S2 shown in FIG.
Since the processing is the same as the processing from 01 to S206, the description is omitted. By the processing of steps S301 to S306, the processing of recording the 2T pattern on the i-track after the initialization of the test track, the processing of setting the amplitude level of this 2T pattern as the initial power-corresponding amplitude level V _2T0 , A process for performing power sweep initialization for P is executed.

If the process of step S407 is executed first after shifting to this routine, step S406
According to the power sweep initial value set in the above, 00 patterns are recorded on the tracks i-1, i + 1. At this time, a 2T pattern is recorded on the track i with the initial laser power value P ₀ .

Step S408 following step S407
In step, the i-track is reproduced, and the subsequent step S40
In step 9, a process of detecting the amplitude level V _2T of the 2T pattern from the reproduction signal obtained by reading the i-track is performed. In this case, detecting the amplitude level V _2T of the 2T pattern in the i-th track is performed in step S3.
At 09, the 00 pattern data recorded on tracks i-1 and i + 1 is cross-talked and recorded on track i, thereby detecting the erasure remaining amount (cross erase amount) of the 2T pattern erased on track i. It is equivalent to doing.

Here, FIG. 7 (c) shows the laser power value at the time of recording in step S407 and the above-mentioned step S40.
9 shows the relationship with the amplitude level V _2T of the 2T pattern in the i-th track detected in FIG. Step S4
07, the laser power value when recording a 2T pattern on tracks i−1 and i + 1 increases,
The cross erase amount of the data of the 2T pattern in the i-track increases, but this has the characteristic that the amplitude level V _2T of the 2T pattern in the i-track decreases as shown in the figure as the laser power value increases. can get. Then, in the present embodiment, step S
409, the amplitude level V _2T of the 2T pattern in the i-track and the amplitude level V _2T corresponding to the initial power.
₀ and for, for example, a laser power value when _{V 2T <V 2T0 × 0.9 ····} ( Equation 7) is satisfied, and is set as crosstalk correspond laser power value P _CRS.

Therefore, in step S410, it is determined whether or not the above-mentioned (Equation 7) holds for the amplitude level V _2T of the 2T pattern detected in step S409. Alternatively, similarly to the case of step S210 in FIG. 3, it is determined whether or not (Equation 3) holds. If a negative result is obtained in step S312, the process advances to step S411 to execute a power sweep process on the laser power (similar to step S211 in FIG. 3), and then returns to step S407.
Accordingly, until it is determined in step S312 that (Equation 7) or (Equation 3) is satisfied, recording of the 2T pattern on tracks i−1 and i + 1 by the laser power gradually increased by the power sweep processing, and i Amplitude level V of 2T pattern in track
_2T detection processing is performed.

If it is determined in step S410 that (Equation 7) or (Equation 3) is satisfied, the process proceeds to step S411, where the current laser power value P
_Is set as the cross-erase compatible laser power value P _ERA .

(E. Setting of Optimal Laser Power Value) Next, the processing operation for setting the optimum laser power value P _ideal will be described. The processing for setting the optimum laser power value P _ideal is the processing operation in step S105 described above with reference to FIG.

In this embodiment, the optimum laser power value P _ideal is set based on the respective laser power values P _OW , P _CRS , and P _ERA detected by the processes shown in FIGS. I have. That is, it is necessary to set the remaining amount of data due to overwriting, the amount of crosstalk, and the amount of cross-erasing so as to satisfy appropriate conditions. Here, FIG. 7A and FIG.
Referring to (c), the detected values of the laser power values P _CRS and P _ERA are detected at a relatively high level, whereas the detected value of the laser power value P _{OW is} the detected value of the laser power values P _CRS and P _CRS . It can be seen that it is detected at a level lower than the detection value of P _ERA . The proper laser power value P _OW is required to be higher than the detection value shown in FIG. 7A due to its characteristics, and the proper laser power values P _CRS and P _ERA are both shown in FIG. 7 (b) and 7 (c). Therefore, the optimum laser power value P _ideal needs to be set within a range higher than the detected value of the laser power value P _OW and lower than the detected values of the laser power values P _CRS and P _ERA. .

Therefore, as the setting processing of the optimum laser power value P _ideal (the processing of step S105 in FIG. 1), for example, P _ideal = {P _OW + (P _CRS + P _ERA ) / 2} / 2. -It is calculated and set according to (Equation 8). This is (P _CRS
+ P _ERA ) / 2, an average value of the laser power values P _CRS and P _ERA that take approximately the same detection value is obtained, and then the average value of the laser power values P _CRS and P _ERA and the laser power value P _OW are calculated. The average is calculated. As a result, the optimum laser power value P _ideal is obtained as a laser power value at a level located substantially in the middle between the detected value of the laser power value P _{OW and} the detected values of the laser power values P _CRS and P _ERA. Will be done.

[0060] Alternatively, as shown in step S105 in FIG. 1, first, the laser power value P _{CR S,} for each detected value of P _ERA, whether there is a P _CRS <P _ERA ··· (Equation 9) (Step S105)
a) If it is determined that the crosstalk-corresponding laser power value P _CRS is smaller, the _ideal laser power value P _ideal is calculated and set according to P _ideal = (P _OW + P _CRS ) / 2 (Equation 10). (Step S105b). On the other hand, if it is determined that the laser power value P _ERA corresponding to the cross erase is smaller, P _ideal = (P _OW + P _ERA ) / 2 (Equation 11) The laser power value P _ideal may be calculated and set (step S105c). In this case, the average value of the smaller of the detected values of the laser power values P _CRS and P _ERA and the laser power value P _OW corresponding to the remaining erasure amount is set as the optimum laser power value P _ideal .

FIG. 10 shows the relationship between the laser power at the time of recording and the error rate of data read from and read from the disk 1. As can be seen from this figure, when data recorded with the optimum laser power value P _ideal set as described above is read, the error rate of the read data is almost the lowest, and this embodiment It is understood that the setting of the optimal laser power value P _ideal according to the above-described embodiment is appropriate.

(E. Laser Power Value Setting Process as Another Embodiment) Next, a laser power value setting process as another embodiment will be described with reference to the flowchart of FIG. In the routine shown in this figure, first, when the laser power setting mode is set in step S501, the laser power value _POW corresponding to the remaining erasure amount is detected in step S502. The detection processing at this time may be the same as the processing shown in FIG. In the laser power value setting processing according to this embodiment, only the laser power value _POW corresponding to the remaining amount of erasure is detected, and the laser power value P
_No detection is performed for _CRS and _PERA . Then, in the subsequent step S503, the _ideal laser power value P _ideal is calculated and set according to P _ideal = (1 + α) × P _OW (Equation 12). At this time, the constant α is set so as to obtain a laser power value close to the optimum laser power value P _ideal obtained in the above embodiment based on, for example, test results. Also in this case, by setting an appropriate constant α, the relationship between the optimum laser power value P _ideal described in FIG. 10 and the error rate of the read data can be obtained.

Thus, the optimum laser power value P
_{When the ideal} is set, for example, the accuracy is not as high as the optimum laser power value P _ideal set according to the above embodiment, but the following advantages are provided. For example, in the above embodiment, when detecting the laser power values P _CRS and P _ERA , FIG.
As can be seen from (c), it is necessary to increase the laser power to a considerably higher level than when the laser power value _POW corresponding to the remaining erasing amount is detected. For example, when such a laser power is raised to a high level, an appropriate detection value cannot be obtained even if the laser power value exceeds an appropriate range due to a difference in conditions. Increasing the power may cause some damage to a laser diode, a disk, or the like in some cases. Also, if the operation of raising the laser power to a high level is frequently performed, the laser diode and the disk may be similarly damaged. On the other hand, when the optimum laser power value P _ideal is set by the processing shown in FIG. 6, it is not necessary to detect the laser power values P _CRS and P _ERA. The operation of raising the level will not be performed. Therefore, it is possible to avoid damage to the laser diode, the disk, and the like due to the setting operation of the laser power.

For the setting of the laser power at the time of recording according to the present invention, either one of the setting methods of the above embodiments may be employed, or both may be employed in combination to satisfy the predetermined condition. It is also conceivable to use differently according to. In the above embodiments, the optimum laser power value P _ideal is set by detecting all the laser power values P _OW , P _CRS , and P _ERA , or the optimum laser power value is detected by detecting only the laser power value P _OW. The case where the value P _ideal is set has been described. For example, the laser power value P _OW corresponding to the remaining amount of erasure is used as essential, and after that, only one of the laser power values P _CRS and P _ERA is detected and used. Such a configuration is also conceivable. Further, if the case, as is not preferable to perform the detection of the laser power value P _OW by, it is also possible to use laser power value P _CRS, by detecting one both or either P _ERA.

Further, the present invention is not limited to the embodiments specifically described above, and can be appropriately changed according to various conditions. For example, the setting of the ratio of the amplitude level of the 2T pattern to the reference value for detecting each of the laser power values P _OW , P _CRS , and P _ERA shown in FIG. 7 is merely an example and may be changed as appropriate. In addition, the present invention is not limited to the recording / reproducing apparatus having the configuration shown as the embodiment, and is naturally applicable to other types of recording apparatuses configured to perform recording on a recording medium by a magnetic field modulation method. It is possible.

[0066]

As described above, according to the present invention, a laser power value corresponding to a remaining erasing amount detected when the remaining erasing amount of data to be overwritten is reduced to a predetermined value or less,
A crosstalk-compatible laser power value detected when the amount of data recorded on an adjacent track obtained as crosstalk during reproduction of a certain track exceeds a predetermined value, and recorded on a track adjacent to the recording track by cross-erase. By using all or any one of the cross-erase compatible laser power values detected in response to the data amount determined to have become equal to or less than a predetermined value,
In the magnetic field modulation method, it is possible to easily set the laser beam output power that is optimized during recording. The remaining amount of data to be overwritten at the time of recording,
Since the amount of crosstalk and the amount of cross-erase of the recorded data are made appropriate, the reliability of the reproduced data is also ensured.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a recording / reproducing apparatus according to an embodiment.

FIG. 2 is a flowchart showing an overall processing operation for setting a laser power at the time of recording according to the embodiment.

FIG. 3 is a flowchart showing a processing operation for detecting a laser power value corresponding to a remaining erasure amount.

FIG. 4 is a flowchart illustrating a processing operation for detecting a crosstalk-compatible laser power value.

FIG. 5 is a flowchart showing a processing operation for detecting a cross-erase compatible laser power value.

FIG. 6 is a flowchart illustrating a processing operation for setting a laser power according to another embodiment.

FIG. 7 is an explanatory diagram showing a relationship between an amplitude level of a 2T pattern and a laser power value for explaining a method for detecting a laser power value corresponding to a remaining erase amount, a laser power value corresponding to a crosstalk, and a laser power value corresponding to a cross erase. It is.

FIG. 8 is an explanatory view conceptually showing a recording area on a disk.

FIG. 9 is an explanatory diagram showing a data format of a test pattern used when setting laser power at the time of recording.

FIG. 10 is an explanatory diagram showing a relationship between laser power during recording and an error rate of read data.

[Explanation of symbols]

1 disc, 2 spindle motor, 3 spindle controller, 4 optical pickup, 4a objective lens, 4
b 2 axis mechanism, 4c laser light source, 4d detector, 4
e Optical system, 5 Laser controller, 6 Controller, 7
I / V conversion matrix amplifier, 8 servo controller, 8a phase compensation circuit, 8b 2-axis driver, 9, 1
2 Clamp circuit, 10, 13 A / D converter, 11
PLL circuit, 14 data detector, 16 tracking error generator, 16a sample and hold circuit, 16b
Error signal generation circuit, 17 timing controller, 19 interface section, 25 encoder, 2
6 magnetic head driver, 27 magnetic head, 30 amplitude detector, 90 host computer, _AT test area, _ACNT control area, _AU user area

Claims (2)

[Claims] 1. A recording magnetic field modulated by recording data is applied to a recording medium as a recording magnetic field, and the recording medium is irradiated with a laser beam having a required laser output power to record data on the recording medium. As a data recording device that can perform this function, it can be used when the remaining erasure amount of the already recorded data when the new data is overwritten on the track on which the data is already recorded becomes less than a predetermined value. The first recording laser power detected as a result and the leakage reproduction amount of the data to be recorded on the specific track at the time of reproduction on the specific track being greater than or equal to a predetermined value are detected. A second recording laser power, and a recording operation of data already recorded on a specific track on a track adjacent to the specific track. The recording laser power is set based on all or a part of the third recording laser power detected when the remaining amount of erasing by the above becomes a predetermined ratio or less with respect to a predetermined reference value. A recording laser power setting means capable of setting the recording laser power. 2. A method for recording data on a recording medium by applying a modulation magnetic field modulated by recording data to a recording medium as a recording magnetic field and irradiating the recording medium with laser light having a required laser output power. The data recording method that can be used is when the remaining amount of erased data that has already been recorded when new data is overwritten on a track on which data is already recorded falls below a predetermined value. The first recording laser power detected as described above and the leakage reproduction amount of the data recorded on the specific track at the time of reproduction on the specific track become equal to or more than a predetermined value. Recording operation of the second recording laser power and data already recorded on a specific track on a track adjacent to the specific track A detection procedure for detecting all or a part of the third recording laser power detected when the remaining erasure amount becomes equal to or less than a predetermined ratio with respect to a predetermined reference value; A setting procedure for setting a recording laser power for performing data recording on a recording medium based on the detection result by the above, and recording data on the recording medium based on the recording laser power set by the setting procedure. A data recording method, wherein a recording procedure to be performed is executed.