JP2002025060A - Optical recording/reproducing device and test write method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording/reproducing device enabling to test- write with high accuracy. SOLUTION: A test pattern generated by a test pattern generating circuit 13 is recorded on a phase transition recording disk 1. This test pattern is reproduced, and an amplitude and a center level of the reproduced signal are measured by an envelope detecting circuit 14, LPF 15, differential circuit 16, A/D conversion circuits 17 and 18. Then, by a circuit 12 for controlling the recording/ reproducing operation, the pulse width of a pulse train and the intensity of a laser beam are decided in such a manner that an asymmetric value, erase rate, etc., are calculated 9 on the basis of the amplitude and the center level of the reproduced signal. Consequently, the influence generating between parameters is reduced by adequately adjusting each pulse width and the intensity of the laser beam, and the highly accurate test write is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing technique for an optical disk having a recording film whose optical state changes according to a change in temperature, and more particularly, to the power and laser power of a laser during recording prior to an information recording operation. The present invention relates to an optical disk recording / reproducing apparatus and a test write method for performing a test write for determining parameters such as a pulse width of light.

[0002]

2. Description of the Related Art In recent years, as the processing speed of microprocessors and the resolution of display devices have increased, the amount of information to be processed has increased dramatically, and accordingly, a large-capacity information recording device has been developed. It is being actively conducted. As a method for recording information, magnetic recording, optical recording, semiconductor memory, and the like can be cited, and optical recording is considered to be the mainstream in terms of portability and storability.

[0003] Among the optical recording methods, a method capable of recording / erasing information, in particular, is a magneto-optical method in which an amorphous alloy is used for a recording layer, and information is recorded by utilizing a polarization angle of reflected light according to the direction of magnetization. Recording, and phase change recording in which information is recorded by utilizing a difference in reflectance between an amorphous state and a crystalline state in the alloy film. Above all, phase change recording has been particularly applied to consumer equipment because it simplifies control because no erasing operation is required in the recording process, and simplifies the device structure because a magnetic head is not required. It is being done.

FIG. 11 is a block diagram showing a schematic configuration of a conventional information recording apparatus using a phase change recording method. This information recording apparatus performs recording / reproducing using a phase change recording disk in which a recording film of a phase change material is applied to a disk-shaped substrate. This information recording apparatus includes a phase change recording disk 101, an optical pickup (PU) 102 for recording / reproducing information by condensing a laser beam on the phase change recording disk 101, and a phase change recording disk 10
1; a spindle motor 103 for rotating the spindle motor 1; a recording information processing circuit 104 for converting information to be recorded on the phase change recording disk 101 into a pulse train to be recorded in accordance with a predetermined rule; Recording pulse generation circuit 105 for converting and outputting a pulse train according to a predetermined rule
5, a laser control circuit 106 for controlling a semiconductor laser to output a laser beam intensity-modulated according to a predetermined rule based on a pulse train output from the optical pickup 102, and a signal photoelectrically converted by the optical pickup 102 into a predetermined signal. RF that amplifies to amplitude, removes unnecessary band signals and outputs
(Radio Frequency) Amplifier 107 and RF Amplifier 10
7, an EQ circuit 108 that performs waveform equalization processing on the signal output from the EQ 7 to emphasize high-frequency components, a binarization circuit 109 that converts the signal output from the EQ circuit 108 into a binary signal,
PLL (Phase Locked Loop) circuit 110 for extracting a reproduction clock from the signal output by the value conversion circuit 109
And a reproduction data detection circuit 111 for restoring and outputting information recorded based on the reproduction clock extracted by the PLL circuit 110.

The phase-change recording disk 101 is provided with a recording film of a phase-change material, and has tracks formed in spiral or concentric grooves or inter-grooves. The spindle motor 103 controls the number of revolutions of the phase change recording disk 101 at a constant number of rotations in a predetermined rotation direction, or such that the focused laser beam scans a track of the phase change recording disk 101 at a constant speed. And rotate.

[0006] The optical pickup 102 is composed of a laser diode, a collimator lens, an objective lens, a photodiode, an actuator and the like. Focusing the laser beam from the laser diode on the recording film of the phase change recording disk 101, and causing the focused laser beam to follow the track formed on the phase change recording disk 101,
The recorded information is reproduced by photoelectrically converting the reflected light with a photodiode.

The phase change material applied to the phase change recording disk 101 is heated to a temperature higher than the melting point and then rapidly cooled to be in an amorphous state, and is further heated to a temperature higher than the crystallization temperature and lower than the melting point and then cooled. Is brought into a crystalline state. Therefore, when recording using a phase change material, it is necessary to control the ultimate temperature of the recording layer and the subsequent temperature change. Therefore, in the normal phase change recording, information is recorded by controlling the temperature reached and the temperature change of the recording film using a pulse train shorter than the minimum unit of the pulse train of the information to be recorded.

FIG. 12 is a diagram for explaining a recording pulse train generally used when information "1" is recorded in an amorphous state in phase change recording. A recording pulse train (LD emission waveform) for forming an amorphous phase corresponding to the recording data "1" is composed of three parts. The first portion is a portion for heating the recording layer to a temperature equal to or higher than the melting point by a single pulse having a width of Ttop and a power of Pp. The second part is Tmp in width,
This is a portion composed of a plurality of pulses of power Pp and keeping the temperature of the recording layer at a constant temperature equal to or higher than the melting point. The third part is a part composed of a single pulse having a width of Tcl and a power of Pb for cooling the temperature of the recording layer heated above the melting point to a crystal temperature below the melting point.

Here, the power Pp is called a recording power and is a power for heating the recording layer to a temperature higher than the melting point.
The power Pb is called a bias power and is a power that does not change the state of the recording layer. In order to bring the recording layer into a crystalline state, as shown in FIG. 12, the recording layer is irradiated with a laser beam at a power Pe called erasing power, which is necessary to heat the recording layer below the melting point and above the crystallization temperature. It is possible by doing.

The recording information processing circuit 104 converts the information to be recorded into a pulse train to be recorded (recording data in FIG. 12) according to a predetermined rule and outputs the pulse train. Further, the recording pulse generation circuit 105 converts the pulse train output from the recording information processing circuit 104 into a pulse train (a pulse train before the LD emission waveform in FIG. 12 is generated) according to a predetermined rule and outputs the pulse train. Further, the laser control circuit 106 controls the laser diode of the pickup 102 so as to output an LD emission waveform obtained by intensity-modulating the pulse train output from the recording pulse generation circuit 105 according to a predetermined rule.

In this way, the recording layer is heated by converging the intensity-modulated laser beam on the phase-change recording disk 101. The recording layer has an amorphous portion and a crystallized portion due to the ultimate temperature and temperature change due to the heating. In general, the reflectance of an amorphous portion (hereinafter, referred to as a mark) is lower than that of a crystallized portion (hereinafter, referred to as a space). , It is possible to reproduce the recorded information.

In general, in high-density optical recording, the length of the shortest recorded mark or space in the track direction is set shorter than the spot diameter of the converged laser beam. So-called intersymbol interference occurs, and the signal near the highest frequency is attenuated, which adversely affects subsequent processing. Therefore, waveform equalization is performed by the EQ circuit 108 so that the signal amplitude of the high-frequency component approaches the ideal state.

As described above, recording / reproduction of information in the phase change recording method is performed. However, since the phase change recording method is a recording method using heat, even when information is recorded with the same power and the same pulse width,
The size of the recorded mark / space changes depending on the structure of the recording medium, the composition of the recording film, the ambient temperature, and the like. In high-density optical recording, mark edge recording for giving information to the edge of a mark / space is usually performed. For this reason, a change in the length of the recorded mark / space in the track direction causes jitter of a reproduced signal and causes an increase in the error rate of the reproduced data.

As described above, in high-density optical recording, the track pitch is set smaller than the spot diameter of the focused laser beam, so that the width of the recorded mark / space increases. This causes crosstalk and cross writing to adjacent tracks. Also, the decrease in the width of the recorded mark / space reduces the amplitude of the reproduced signal, which causes the error rate of the reproduced data to deteriorate.

For this reason, a test write method has been proposed in which a test signal is recorded before an information recording operation is performed, and parameters such as the power of a laser diode and the pulse width of a laser beam at the time of recording are determined. I have.
The related art related to this will be described below.

An optical recording / reproducing apparatus disclosed in Japanese Patent Application Laid-Open No. 2-128326 discloses a method of recording a laser beam on a track for recording an information signal or a track near the track immediately before recording an information signal. A signal is recorded while changing the light emission amount, and the optimum light emission amount of the laser light source for recording is detected and set from the reproduced signal.

The optical disk device disclosed in Japanese Patent Application Laid-Open No. Hei 6-139574 discloses a pattern data having two or more "1" s, a data having a pattern having two or more "0s", and a modulation method. The test data including the data of the pattern of the maximum frequency in the above is recorded, and the peak value of the reproduction signal amplitude of the data of the pattern followed by two or more “1” s and the data of the pattern followed by the two or more “0s” The recording power of the semiconductor laser is set such that the median value of the peak value of the reproduced signal amplitude and the average value of the reproduced signal amplitude of the data of the pattern of the maximum frequency are substantially equal to each other.

Further, the test write method disclosed in Japanese Patent Application Laid-Open No. 9-231571 discloses a test write method in which a power level for forming an erased state based on the relationship between the recording power of a predetermined signal and the amplitude of the reproduced signal, and a predetermined length. A first power level for forming a recording state based on a relationship between a recording power of two different signals and an intermediate value of the reproduction signal, a recording power of a predetermined signal and a difference between a positive and negative amplitude of a reproduction differential signal of the predetermined signal. The second power level for forming the recording state is determined based on the relationship, and the optimum power for forming the erasing state and the recording state is determined based on the obtained result and the ratio of the amorphous state and the erasing state on the recording medium. Determine the level.

The optical information recording / reproducing apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 6-231463 changes the recording power in one sector in a step-by-step manner, measures the amplitude of the reproduced signal, and measures the amplitude data. Is determined as the optimum recording power.

Further, in the recording method disclosed in Japanese Patent Application Laid-Open No. 6-295439, the power of the laser is kept constant, and the pulse width of the test recording is increased or decreased around a set value serving as a reference. Then, the result is reproduced, statistical processing is performed, and recording conditions for recording user data are set based on the obtained result.

In the information recording / reproducing method disclosed in Japanese Patent Application Laid-Open No. 9-219021, information is test-recorded in a pattern consisting of an unrecorded portion and a recorded portion while sequentially changing the recording power, and the test recording is performed. The optimum recording power is determined by reproducing information and monitoring the recording signal amplitude corresponding to the recording power, and evaluating the excess or deficiency of the recording power based on the standardized slope.

In the erasing power setting method disclosed in Japanese Patent Application Laid-Open No. 10-188286, a test signal is recorded on a certain track on a disk, and the track is reproduced by tracing the track with a DC light emitting laser of Pe power. The state of erasing of the mark portion of the signal is checked, and the erasing power is set at the point of the optimum erasing power. Power P used for this trace
e is gradually increased from a small initial value at which the recorded signal does not disappear, and the power Pe at a point exceeding a predetermined threshold and thereafter at a point below the threshold again is stored. , Based on which the optimum erasing power is determined.

The optical disk recording method disclosed in Japanese Patent Application Laid-Open No. 10-64064 conducts test recording by changing write power, erase power, and bottom power, respectively, and reproduces the test recording to obtain an optimum asymmetry value. Or the optimum values of the write power, erase power, and bottom power at which the modulation degree becomes optimum or the error rate becomes the lowest, and actual recording is performed using a combination of these optimum values.

The recording method disclosed in Japanese Patent Application Laid-Open No. H10-320777 discloses a method of recording the same mark repetition pattern or random mark pattern and detecting a shift between a clock and a data edge of the mark from a reproduction signal. The threshold power for recording is obtained, and the recording power is optimized by multiplying the threshold power by a constant.

[0025]

FIG. 13 is a graph showing a change in jitter with respect to a change in the parameters Pe, Tcl, Ttop, Tmp or Pp described above. FIG. 13 (a)
As can be seen from FIG. 13E, the effect on the jitter value differs depending on the parameter. In particular, FIG.
As shown in (d), it has been found that the pulse width Tmp of the pulse train of the second portion is a parameter that easily affects the jitter value. The reason for this is that Tmp is a parameter for controlling heat accumulation at the time of mark formation. If heat is accumulated too much, the rear end of the mark moves backward, the mark length becomes longer, and heat accumulation becomes insufficient. Then, the rear end of the mark moves forward and the mark length is shortened, so that the jitter value is deteriorated.

However, as described above, the conventional test write method mainly relates to the optimization of the recording power Pp, and does not disclose the optimization of the pulse width of the recording pulse.

FIG. 14 shows parameters Pe, Tcl,
9 is a graph showing a change in asymmetry value with respect to a change in Ttop, Tmp or Pp. 14 (a) to 14
As can be seen from (e), the degree of influence on the asymmetry value differs depending on the parameter, and in particular, Tcl,
Ttop and Pp greatly affect the asymmetry value. The reason is that the recording depth when forming a relatively short mark is easily affected by these three parameters. As shown in FIGS. 14A to 14E, the asymmetry value changes almost linearly with a change in the parameter, and thus is suitable as an index of the test light, but is affected by the parameter. There is a problem that it is easy.

FIG. 15 is a diagram for explaining the effect of the asymmetry value between the parameters. For example, it is assumed that a test write using only Pp is performed on two types of disks, medium 1 and medium 2. Here, the parameter values that minimize the jitter value of these two disks were measured.
Are both Pp1, and for Tcl, it is assumed that the medium is Tcl1 and the medium 2 is Tcl2.

It is assumed that the parameters other than Pp are set to appropriate values and the asymmetry of the two discs is measured while changing Pp, as shown in FIG. It is assumed that the value of Tcl at this time is Tcl1.
According to the conventional test write method, the Pp value when the asymmetry is 0 becomes the optimum value. Therefore, in the medium 1, the optimum value is close to the Pp value at which the jitter value is minimum, but in the medium 2, the optimum value is Is a value far away from the Pp value at which the jitter value is minimized. This is because the asymmetry was affected by another parameter, in this case the Tcl value.

FIG. 15B is a graph showing the relationship between the Tcl value and the asymmetry value. As shown in FIG. 15B, since the asymmetry is different between the medium 1 and the medium 2 even though they have the same Tcl value, the same T
When a test write of another parameter is performed using the cl value, for example, Tcl1, there is a high possibility that the value will be different from the originally expected value. In the conventional test write method, there is no method that pays attention to this point, and there is a problem that a stable test write cannot be performed.

As shown in FIG. 14 (a), depending on the medium, the Pe value hardly affects the asymmetry value, and the test write of the Pe value based on the asymmetry may not be performed. Do you get it.

The present invention has been made to solve the above problems, and a first object of the present invention is to provide an optical disk recording / reproducing apparatus and a test write method capable of performing a highly accurate test write.

A second object is to provide an optical disk recording / reproducing apparatus and a test writing method capable of performing a test write flexibly corresponding to the performance required of the optical disk recording / reproducing apparatus.

[0034]

According to one aspect of the present invention, a pulse train corresponding to information to be recorded is converted into a pulse train finer than the minimum unit of information, and the intensity of the laser beam is modulated by the fine pulse train. Focuses and heats the intensity-modulated laser beam on the recording layer on the medium, records information by changing the optical state according to the temperature distribution,
At the time of reproduction, a relatively weak laser beam is focused on the recording layer,
An optical recording / reproducing apparatus for reproducing information recorded on a recording layer in a state of the reflected light, comprising: a recording / reproducing operation control means for controlling a recording / reproducing operation based on an external operation request; An access control means for moving the focused laser beam to a predetermined position based on a command from the control unit; and a first predetermined pattern including at least a relatively long pattern repetition based on a command from the recording / reproduction operation control means. A pattern, a test pattern generating means for selecting and outputting one of a second predetermined pattern mainly including at least a relatively long pattern repetition and a relatively short pattern repetition, and a command from the recording / reproduction operation control means. , A pulse train corresponding to the information to be recorded or an output signal from the test pattern generator is selected to generate a recording pulse. Means for raising the temperature of the recording layer to a first temperature or higher that can change the optical state of the recording layer to the first state, based on a command from the selecting means output to the means, and a command from the selecting means and the recording / reproducing operation control means. A first pulse train, a second pulse train for keeping the temperature of the recording layer at or above the first temperature,
Recording pulse generating means for generating a third pulse train for cooling the recording layer to a temperature higher than a second temperature which can change an optical state of the recording layer to a second state and lower than the first temperature; and a recording pulse. A first power for heating the recording layer to a first temperature or higher based on the three types of pulse trains output from the generating means and a command from the recording / reproducing operation control means, and a second power supply for heating the recording layer to the second temperature. Laser control means for modulating the power of the laser beam between a second power for heating to a temperature equal to or higher than the first temperature and a third power for which the state of the recording layer does not change, and reproduction of a recorded pulse train A reproducing signal amplitude measuring means for measuring a signal amplitude; and a reproducing signal center level measuring means for measuring a central level of a reproducing signal of a recorded pulse train. Parame To a test write mode for determining the laser beam spot to a predetermined position, output a command to the access control means, a test pattern to select a predetermined test pattern as a recording pulse generating means input signal, A command is output to the generating means and the selecting means, the outputs of the reproduced signal amplitude measuring means and the reproduced signal center level measuring means are processed according to a predetermined algorithm, and the second power, the pulse width of the third pulse train, the first pulse The pulse width of the pulse train, the pulse width of the second pulse train,
It operates to determine the parameters in the order of the first power.

By determining the parameters in this order, errors due to the influence between the parameters can be reduced, and a highly accurate test write can be performed.

Preferably, the relatively long pattern is sufficiently longer than the spot diameter of the laser beam, and the relatively short pattern is the shortest pattern of the modulation method used for recording information.

Preferably, the first and second predetermined patterns include a synchronization pattern during normal recording.

Preferably, the recording / reproduction operation control means outputs an instruction to the test pattern generation means and the selection means so that the first predetermined pattern is output to the recording pulse generation means in the second power determination process. And the first
During the predetermined length, a first predetermined pattern is recorded with a predetermined parameter value, and after the recording is completed, an instruction is issued to the access control means to move the spot of the laser beam to the recording start position of the first predetermined pattern. Outputting and reproducing the recorded first predetermined pattern, the second predetermined pattern being shorter than the first length.
The output of the reproduction signal amplitude measuring means for each section of the predetermined length is stored as a first value, and after the reproduction operation is completed, the laser beam spot is again moved to the recording start position of the first predetermined pattern. Recording pulse generating means and laser control means for outputting a command to the control means and erasing the recorded first predetermined pattern by a laser beam which is not intensity-modulated and whose power increases or decreases every second length section To the access control means to move the spot of the laser beam to the recording start position of the first predetermined pattern after the end of the erasing operation, and to reproduce the erased first predetermined pattern; The output of the reproduction signal amplitude measuring means for each section of the second predetermined length is stored as a second value, and the erasure rate for each section of the second length is calculated from the first value and the second value. Request Operative to determine a second power from this value.

Since the second power is determined based on the erasure rate, it is possible to determine the second power without being affected by the relationship between the uncertain second power and the asymmetry.

[0040] More preferably, the recording / reproducing operation control means finds a difference in erasure rate between adjacent second length sections,
The minimum value of the power not intensity-modulated so that the value becomes equal to or less than a predetermined value is obtained, the value is corrected by performing a first predetermined operation, and the result is set as a second power setting value. .

By performing the first predetermined operation on the minimum value of the power to obtain the second power, it is possible to determine the optimum second power.

Preferably, the recording / reproducing operation control means includes a step of determining the second pulse width in the third pulse train.
A command is output to the test pattern generation means and the selection means so that the predetermined pattern is output to the recording pulse generation means, and a command is output to the access control means so as to move the spot of the laser beam to a predetermined position. And outputting a command to the recording pulse generating means and the laser control means so as to record the second predetermined pattern by increasing or decreasing the pulse width of the third pulse train for each section of the second length. 2 to output a command to the access control means to move the spot of the laser beam to the recording start position of the second predetermined pattern, reproduce the recorded second predetermined pattern, and read the second predetermined pattern for each section of the second predetermined length. The output of the reproduction signal center level measuring means is stored, and the pulse width of the third pulse train is determined from the stored value.

Accordingly, it is possible to determine the pulse width of the third pulse train so that the reproduced signal is optimized.

More preferably, the recording / reproducing operation control means detects a portion corresponding to a relatively short pattern and a portion corresponding to a relatively long pattern from the stored values, and for each section of the second length. The difference is obtained, the pulse width of the third pulse train whose difference is 0 is obtained from the relationship between the result and the pulse width of the third pulse train at the time of recording, and a second predetermined calculation is performed on the value. The operation is performed so that the result is corrected and the result is used as the set value of the pulse width of the third pulse train.

Therefore, it is possible to determine the pulse width of the third pulse train so that symmetry is optimized.

Preferably, the recording / reproducing operation control means includes the step of determining the pulse width of the first pulse train.
A command is output to the test pattern generation means and the selection means so that the predetermined pattern is output to the recording pulse generation means, and a command is output to the access control means so as to move the spot of the laser beam to a predetermined position. A command is output to the recording pulse generation means and the laser control means so as to record the second predetermined pattern by increasing or decreasing the pulse width of the third pulse train for each section of the second length. A command is outputted to the access control means so as to move the spot of the laser beam to the recording start position of the second predetermined pattern, the recorded second predetermined pattern is reproduced, and the section of the second predetermined length is outputted. An operation is performed to store the output of the reproduction signal center level measuring means for each and determine the pulse width of the first pulse train from the stored value.

Therefore, it is possible to determine the pulse width of the first pulse train so that the reproduced signal is optimized.

More preferably, the recording / reproducing operation control means detects a portion corresponding to a relatively short pattern and a portion corresponding to a relatively long pattern from the stored values, and for each section of the second length, The difference is obtained, the first pulse train having a difference of 0 is obtained from the relationship between the result and the pulse width of the first pulse train at the time of recording, and a third predetermined calculation is performed on the value. The operation is performed so that the result of the correction is set as the set value of the pulse width of the third pulse train.

Therefore, it is possible to determine the pulse width of the first pulse train so that the asymmetry is optimized.

Preferably, the recording / reproducing operation control means includes the second pulse train in the process of determining the pulse width of the second pulse train.
A command is output to the test pattern generation means and the selection means so that the predetermined pattern is output to the recording pulse generation means, and a command is output to the access control means so as to move the spot of the laser beam to a predetermined position. And outputting a command to the recording pulse generating means and the laser control means so as to record the second predetermined pattern by increasing or decreasing the pulse width of the third pulse train for each section of the second length. 2 to output a command to the access control means to move the spot of the laser beam to the recording start position of the second predetermined pattern, reproduce the recorded second predetermined pattern, and read the second predetermined pattern for each section of the second predetermined length. The output of the reproduction signal center level measuring means is stored, and the pulse width of the second pulse train is determined from the stored value.

Therefore, it is possible to determine the pulse width of the second pulse train so that the reproduced signal is optimized.

More preferably, the recording / reproducing operation control means detects a portion corresponding to a relatively short pattern and a portion corresponding to a relatively long pattern from the stored values, and for each section of the second length. The difference is obtained, the relationship between the result and the pulse width of the second pulse train at the time of recording is approximated to two straight lines, and the pulse width of the second pulse train at the intersection of the two straight lines is calculated. The obtained value is corrected by performing a fourth predetermined operation, and the result is used as the set value of the pulse width of the second pulse train.

Therefore, the pulse width of the second pulse train can be determined so that the asymmetry is optimized.

Preferably, the recording / reproducing operation control means outputs a command to the test pattern generation means and the selection means so that the second predetermined pattern is output to the recording pulse generation means in the first power determination process. Then, to move the spot of the laser beam to a predetermined position,
A command is outputted to the access control means, and a command is outputted to the recording pulse generating means and the laser control means so as to record the second predetermined pattern by increasing or decreasing the first power for each section of the second length. Then, after the recording operation is completed, a command is outputted to the access control means so as to move the spot of the laser beam to the recording start position of the second predetermined pattern, the recorded second predetermined pattern is reproduced, and the second predetermined pattern is reproduced. The operation is performed to store the output of the reproduction signal center level measuring means for each section of the length, and to determine the first power from the stored value.

Therefore, it is possible to determine the first intensity so that the reproduced signal is optimal.

More preferably, the recording / reproducing operation control means detects a portion corresponding to a relatively short pattern and a portion corresponding to a relatively long pattern from the stored values, and for each section of the second length. The difference is obtained, the first power at which the difference becomes 0 is obtained from the relationship between the result and the first power at the time of recording, and the value is corrected by performing a fifth predetermined operation on the value. The operation is performed so that the result is set to the first power setting value.

Therefore, it is possible to determine the first intensity so that the asymmetry is optimized.

Preferably, in the process of determining the second power, the recording / reproducing operation control means records the first pattern and sets the first and second powers for recording the maximum power in the normal recording. Set to power,
The pulse widths of the first to third pulse trains operate so as to output a command to the recording pulse generating means and the laser control means so as to set a standard value in normal recording.

More preferably, in the process of determining parameters other than the second power, the recording / reproducing operation control means sets the determined values for the parameters determined in the process before the process currently in progress. Then, it operates to output a command to the recording pulse generating means and the laser control means to record the second pattern.

Preferably, the reproduced signal amplitude measuring means comprises a high level envelope detecting means for detecting a high level envelope of a relatively long pattern reproduced signal and a low level envelope of a relatively long pattern reproduced signal. It includes a low-level envelope detection means for detecting, a difference means for obtaining a difference between outputs of the high-level and low-level envelope detection means, and an A / D conversion means for A / D converting an output of the difference means.

Preferably, the reproduction signal center level measuring means includes a low-pass filter having a cutoff frequency lower than a frequency corresponding to a relatively long pattern, and an A / D converter for A / D-converting an output of the low-pass filter. And

According to another aspect of the present invention, a pulse train corresponding to information to be recorded is converted into a pulse train finer than the minimum unit of information, and the intensity of the laser beam is modulated by the fine pulse train. A test write method for an optical recording / reproducing apparatus in which a beam is focused on a recording layer on a medium and heated, and the optical state is changed according to the temperature distribution to record information. A first state that can change an optical state to a first state;
A first pulse train for raising the temperature of the recording layer above the first temperature, a second pulse train for keeping the temperature of the recording layer above the first temperature, and changing the optical state of the recording layer to the second state. A third pulse train for cooling to a temperature equal to or higher than the second temperature and lower than the first temperature, wherein the intensity of the laser beam is at least equal to the first temperature for heating the recording layer to at least the first temperature.
, A second power for heating the recording layer to a temperature equal to or higher than the second temperature and lower than the first temperature, and a third power that does not change the state of the recording layer.
A first step of determining the power of the first pulse train, a second step of determining the pulse width of the third pulse train, a third step of determining the pulse width of the first pulse train, and the pulse width of the second pulse train And a fifth step of determining a first power.

By determining the parameters in this order, errors due to the influence between the parameters can be reduced, and a highly accurate test write can be performed.

Preferably, in the first step, a first predetermined pattern is recorded, the recorded mark is erased by a laser beam which is not intensity-modulated, and the amplitude of a reproduced signal when the mark portion is reproduced before and after the erasure is recorded. Determining a ratio and determining a second power from the result.

Since the second power is determined based on the erasing rate, the second intensity can be determined without being affected by the uncertain relationship between the second intensity and the asymmetry.

More preferably, the step of determining the second power includes the step of recording a first predetermined pattern in a section of a first length, and the step of recording a recorded mark in a second section shorter than the first length. Erasing with a non-intensity-modulated laser beam whose power increases or decreases for each length section, and obtains an erasure rate for each second length section, and the difference between the erasure rates of adjacent sections is equal to or less than a predetermined value. And determining the second power by correcting the power value by the first operation to determine the second power.

The first operation is performed on the minimum value of the power to obtain the second value.
With this power, it is possible to determine the optimal second power.

More preferably, the first predetermined pattern includes a repetition of a pattern that is at least sufficiently longer than the spot diameter of the focused laser beam.

Preferably, in the second step, a second predetermined pattern mainly including repetition of a relatively short pattern and repetition of a relatively long pattern is recorded, and a center level of the amplitude of a reproduced signal of the short pattern is recorded. Detecting the center level of the amplitude of the reproduced signal having a long pattern and determining the pulse width of the third pulse train based on the detection result.

Therefore, it is possible to determine the pulse width of the third pulse train so that the reproduced signal is optimized.

More preferably, in the step of determining the pulse width of the third pulse train, the second predetermined pattern is recorded by increasing or decreasing the pulse width of the third pulse train for each section of the second length. A step of detecting a central level of the amplitude of the reproduced signal of the short pattern and a central level of the amplitude of the reproduced signal of the long pattern for each second length section to obtain a difference therebetween; From the relationship between the pulse width and the difference between the center levels, the pulse width of the third pulse train in which the difference between the center levels becomes 0 is obtained, and the result is corrected by a second operation to obtain the pulse width of the third pulse train. Seeking.

Therefore, it is possible to determine the pulse width of the third pulse train so as to optimize the symmetry.

Preferably, in the third step, a second predetermined pattern mainly including repetition of a relatively short pattern and repetition of a relatively long pattern is recorded, and the center level of the amplitude of the reproduced signal of the short pattern is recorded. Detecting the center level of the amplitude of the reproduced signal having a long pattern, and determining the pulse width of the first pulse train based on the detection result.

Therefore, it is possible to determine the pulse width of the first pulse train so that the reproduced signal is optimized.

More preferably, in the step of determining the pulse width of the first pulse train, the second predetermined pattern is recorded by increasing or decreasing the pulse width of the first pulse train for each section of the second length. Detecting the difference between the center level of the amplitude of the reproduced signal of the short pattern and the center level of the amplitude of the reproduced signal of the long pattern for each second length section; From the relationship between the pulse width and the difference between the center levels, the pulse width of the first pulse train in which the difference between the center levels is 0 is obtained, and the result is referred to as the third pulse.
And determining the pulse width of the first pulse train by performing the correction by the above calculation.

Therefore, it is possible to determine the pulse width of the first pulse train so that asymmetry is optimized.

Preferably, in the fourth step, a second predetermined pattern mainly including repetition of a relatively short pattern and repetition of a relatively long pattern is recorded, and the center level of the amplitude of the reproduced signal of the short pattern is recorded. Detecting the center level of the amplitude of the reproduced signal having a long pattern and determining the pulse width of the second pulse train based on the detection result.

Therefore, it is possible to determine the pulse width of the second pulse train so that the reproduced signal is optimized.

More preferably, in the step of determining the pulse width of the second pulse train, the second predetermined pattern is recorded by increasing or decreasing the pulse width of the second pulse train for each section of the second length. Detecting the difference between the central level of the amplitude of the reproduced signal of the short pattern and the central level of the amplitude of the reproduced signal of the long pattern for each section of the second length; The relationship between the pulse width and the difference between the center levels is approximated by two straight lines, the pulse width of a third pulse train corresponding to the intersection of the two straight lines is obtained, and the result is corrected by a fourth operation. Second
And determining the pulses of the pulse train.

Therefore, it is possible to determine the pulse width of the second pulse train so that the asymmetry is optimized.

Preferably, in the fifth step, a second predetermined pattern mainly including repetition of a relatively short pattern and repetition of a relatively long pattern is recorded, and a center level of an amplitude of a reproduced signal of the short pattern is recorded. Detecting the center level of the amplitude of the reproduced signal having a long pattern and determining the first power based on the detection result.

Accordingly, it is possible to determine the first intensity so that the reproduced signal is optimal.

More preferably, the step of determining the first power includes the step of increasing or decreasing the first power for each section of the second length to record a second predetermined pattern; Detecting a center level of the amplitude of the reproduced signal of the short pattern and a center level of the amplitude of the reproduced signal of the long pattern for each section of the length to obtain a difference therebetween; From the relationship,
Determining a first power at which the difference between the center levels becomes 0, and correcting the result by a fifth operation to determine the first power.

Therefore, the first intensity can be determined so that the asymmetry is optimized.

More preferably, among the second predetermined patterns, the relatively short pattern is the shortest pattern of the modulation system used for recording information, and the relatively long pattern is the spot of the focused laser beam. The pattern is sufficiently longer than the diameter.

More preferably, the first and second predetermined patterns include a synchronization signal for recording information.

Preferably, in the first step, the first and second powers are set to maximum powers in normal recording, the pulse widths of the first to third pulse trains are set to standard values in normal recording, Recording a pattern to determine a second power.

Preferably, the step of determining a parameter other than the second power uses the determined value for a parameter determined in a step other than the step currently in progress, and uses the determined value for an undetermined parameter. The second pattern is recorded using the value adopted in the step of determining the power of No. 2.

[0089]

FIG. 1 is a block diagram showing a schematic configuration of an optical disk recording / reproducing apparatus according to an embodiment of the present invention. This optical disk recording / reproducing apparatus performs recording / reproduction using a phase-change recording disk in which a recording film of a phase-change material is applied to a disk-shaped substrate. In the optical disk recording / reproducing apparatus according to the present embodiment, the shortest pattern 3T and the longest pattern 11T are EFM (Eight to Eight).
Fourteen Modulation) A case of recording using Plus modulation will be described.

This optical disk recording / reproducing apparatus includes a phase change recording disk 1, an optical pickup (PU) 2 for recording / reproducing information by condensing a laser beam on the phase change recording disk 1, and a phase change recording. A spindle motor 3 for rotating the disk 1 and a phase change recording disk 1
A recording information processing circuit 4 that converts information to be recorded into a pulse train to be recorded according to a predetermined rule and outputs the same, and a recording pulse that converts a pulse train output from the recording information processing circuit 4 to a pulse train according to a predetermined rule and outputs the pulse train Generation circuit 5
A laser control circuit 6 for controlling a semiconductor laser to output a laser beam obtained by intensity-modulating the pulse train output from the recording pulse generation circuit 5 according to a predetermined rule;
R which amplifies the signal photoelectrically converted by the optical pickup 2 to a predetermined amplitude, removes an unnecessary band signal, and outputs the signal.
An F-amplifier 7, an EQ circuit 8 for waveform equalizing the signal output from the RF amplifier 7 to emphasize high-frequency components, and a binarization for converting the signal output from the EQ circuit 8 into a binary signal A circuit 9, a PLL circuit 10 for extracting a reproduction clock from a signal output by the binarization circuit 9, and a PLL circuit 1
A reproduced data detecting circuit 11 for restoring and outputting the recorded information based on the reproduced clock extracted by 0
A recording / reproducing operation control circuit 12 for performing overall control of the optical disk recording / reproducing apparatus; a test pattern generating circuit 13 for generating a test pattern to be written on the phase change recording disk 1; An envelope detection circuit 14 for detecting and outputting the envelope of the first and lower envelopes; an LPF (Low Pass Filter) 15 to which a signal from the RF amplifier 7 is input;
A difference circuit 16 that outputs a difference between the amplitudes of the upper envelope and the lower envelope output from the envelope detection circuit 14, and an A / D (Analog / Digital) conversion circuit 18 to which an output signal of the difference circuit 16 is input. And LPF15
And an A / D conversion circuit 17 to which the output signal is input.

When the phase change recording disk 1 is inserted into the optical disk recording / reproducing apparatus shown in FIG. 1, or when a recording start command is input to the recording / reproducing operation control circuit 12 from a controller (not shown), for example, a key switch or the like. It is determined whether or not a test write is necessary. When a test write is required, for example, when an unrecorded phase change recording disk 1 is inserted, a test write operation is performed.

When it is determined that a test write is necessary, the recording / reproduction operation control circuit 12 controls the test pattern generation circuit 13, the recording pulse generation circuit 5, and the laser control circuit 6 to write data to the phase change recording disk 1. Start writing the test pattern or erasing the test pattern. The writing of the test pattern or the erasing of the test pattern is performed on a predetermined sector of the phase change recording disk 1.

FIG. 2 is a diagram showing two types of test patterns output from test pattern generation circuit 13. Test pattern 1 shown in FIG. 2A is a pattern in which a synchronization pattern is inserted at the same interval as that of normal recording in a longest pattern of 11T, which is a repetition pattern. FIG.
The test pattern 2 shown in (b) has a repeating pattern of the shortest pattern 3T which is half the length of the synchronization pattern interval, a repeating pattern of 11T which is the longest pattern,
It consists of a synchronization pattern. The 11T repetition pattern is a pattern sufficiently longer than the spot diameter of the laser beam, and the 3T repetition pattern corresponds to the shortest pattern of the modulation method used when recording information.

In a normal recording state, a plurality of synchronization patterns are arranged at predetermined intervals in one sector.
By writing the two types of test patterns shown in (1), one sector can be divided into integer multiples of the synchronization pattern interval. By performing the test write using this length as a basic unit (hereinafter, referred to as a test write sector), it is possible to flexibly cope with the performance required of the optical disk recording / reproducing apparatus.

For example, if the test write is performed in a short time, the test write sector which is a basic unit may be shortened, and if the test write is performed with high accuracy, the test write sector may be lengthened. here,
Assume that the number of synchronization frames in one sector (hereinafter, the period from the beginning of the synchronization pattern to immediately before the next synchronization pattern is defined as one synchronization frame) is S, and the test write sector is composed of U synchronization frames. Then, S / U is assumed to be an integer.

The reproduction signal contained in the reflected light from the phase change recording disk 1 is amplified by the RF amplifier 7 and input to the EQ circuit 8, the envelope detection circuit 14, and the LPF 15. The envelope detection circuit 14 detects and outputs an upper envelope and a lower envelope of the 11T repetitive signal included in the test pattern. LPF1
5 has a lower cutoff frequency than the frequency corresponding to the 11T repetitive signal, so its output will represent the center level of the input signal.

The difference circuit 16 is an envelope detection circuit 1
The difference between the upper envelope and the lower envelope of the 11T repetition signal output from 4, ie, the amplitude of the 11T repetition signal, is obtained and output. A / D conversion circuit 17
And 18 are the LPF 15 and the difference circuit 16 respectively.
Is converted into digital data and output to the recording / reproduction operation control circuit 12. Recording / reproduction operation control circuit 12
Processes the digital data output from the A / D conversion circuits 17 and 18 according to an algorithm described later to determine parameters. The recording / reproduction operation control circuit 12
Are CPU (Central Processing Unit), DSP (Dig
The following processing can be realized by executing a program recorded in the memory by an ital Signal Processor or the like.

FIG. 3 is a block diagram showing a functional configuration of the recording / reproduction operation control circuit 12 shown in FIG. The recording / reproducing operation control circuit 12 includes a recording data control unit 21 that outputs a signal for controlling data to be recorded on the phase change recording disk 1 to the test pattern generation circuit 13 and the recording pulse generation circuit 5, and a laser control circuit 6 In addition, a parameter setting unit 22 that outputs the above-described parameter setting value to the recording pulse generation circuit 5 and a thread (not shown) for moving the optical pickup 2 and an objective lens for condensing a laser beam are moved in the cross-track direction. An access control unit 23 for outputting a command signal for causing a laser beam to access a predetermined sector to each driver of the radial actuator to be operated;
An operation unit 24 that performs a predetermined operation based on the synchronization signal detection signal from 1 and the outputs of the A / D conversion circuits 17 and 18;
It includes a recording data control unit 21, a parameter setting unit 22, an access control unit 23, and a control unit 25 for controlling the calculation unit 24 based on a command from a CPU (not shown) and a calculation result of the calculation unit 24.

FIG. 4 is a flowchart for explaining the overall processing procedure of the recording / reproduction operation control circuit 12.
In the present embodiment, Pe, Tcl, Ttop, Tmp, Pp
Test write is performed in the following order. At this time, for parameters other than the parameter for which test writing is being performed, the values are used if they have already been determined. If the power has not yet been determined, the maximum value during normal recording is used for power, and a standard value is used for pulse width. The standard value of the pulse width may be a standard value determined at the time of disk specification or a value determined by a disk manufacturer and recorded on the disk.

As described above, the parameters Pe, Tcl,
Since Ttop has little effect on the jitter value, it need not be determined as accurately as other parameters, but Tcl and Tto
Since p has a large effect on the asymmetry value, it is necessary to find a value close to the optimum value to some extent, and perform test writing of other parameters with that value. Therefore, by determining these parameters by the test write first, errors due to the influence between the parameters, which has been a problem in the conventional test write method, are reduced, and a highly accurate test write can be performed.

For a Pe test write, after a long repetitive pattern is recorded, DC erasure is performed by changing the power, and is determined based on the erasure rate expressed by the ratio of the amplitude of the reproduced signal before and after erasure. . by this,
Pe can be determined without being affected by the relationship between uncertain Pe and asymmetry, which has been a problem in the conventional test write method.

As shown in FIG. 4, when the test write is started, first, the recording data control section 21 sets a pattern (test pattern) consisting of a repeating pattern of 11T shown in FIG. An instruction signal is output to the test pattern generation circuit 13 and the recording pulse generation circuit 5 so that 1) is selected (S1). Then, the parameter value Pp is set by the parameter setting unit 22.
And Pe as the maximum values Pp _max and Pe _max for normal recording
And set the standard value Ttop as Ttop, Tmp and Tcl
After setting _std , Tmp _std and Tcl _std (S2), P
The test write for e is executed (S3).

FIG. 5 is a flowchart for explaining the processing of step S3 in FIG. 4 in more detail. First,
The access control unit 23 issues a command to each driver of the thread and the radial actuator to cause the laser beam to access a predetermined sector K (S31). In the phase change recording disk 1, address information indicating the relative position on the disk is usually formed at the time of manufacture, and the access control unit 31 detects this and recognizes the sector currently scanned by the laser beam. it can. When it is confirmed that the laser beam has accessed the predetermined sector K, the recording data control unit 21 controls the test pattern generation circuit 13 to execute 11T from the sector K to the predetermined number N of sectors.
Is recorded with the parameters set in step S2 (S32).

Next, the access control section 23 accesses the predetermined sector K again with the laser beam (S33), and then reproduces the test pattern recorded on the phase change recording disk 1, and the reproduction data detection circuit 11 Based on the synchronization signal detection signal and the output from the A / D conversion circuit 18, the arithmetic unit 2
No. 4 finds the average amplitude of the reproduced signal of the 11T repetitive signal for each test write sector (S34). At this time, the reproduced signal average amplitude for each test write sector is represented by I11 _i (i = 1 to 1).
J, J = N × (S / U)).

Next, the DC erasing mode is set as the recording mode (S35), and the parameter setting section 22 sets Pe to Pe.
_min is set (S36). A command is issued to the access control unit 23 thread and the radial actuator to access the predetermined sector K with the laser beam (S37), and DC erasure is performed by DC light whose intensity is not modulated (S3).
8). At this time, the parameter setting unit 22 outputs a value obtained by adding ΔPe from the sector K for each test write sector to the laser control circuit 6 as a DC erasing power setting value. The value of the parameter Pe at this time is represented by the following equation.

Pe = Pe _min + ΔPe × (i−1) (i = 1 to N) (1) Then, the access control unit 23 again issues a command to the sled and the radial actuator to change the laser beam to a predetermined sector K. (S39), and reproduces the test pattern recorded on the phase change recording disk 1. Based on the synchronization signal detection signal from the reproduction data detection circuit 11 and the output from the A / D conversion circuit 18, the arithmetic unit Reference numeral 24 denotes a reproduced signal average amplitude I11e of a repetition signal of 11T for each sector.
_i (i = 1 to J) is obtained (S40). The calculation unit 24
The reproduced signal average amplitude I measured in step S34
And 11 _i, to calculate the erasure ratio E _i shown in the following equation from the measured and the reproduction signal average amplitude I11e _i in step S40 (S41).

E _i = _I 11 e _i / I 11 _i (i = 1 to N) (2) The relationship between the DC erasing power and the erasing rate E is as shown in FIG. Since Pe is a parameter that affects the erased state at the time of overwriting, it is necessary to find the necessary power at the time of DC erasing. As can be seen from FIG. 10A, if the erasing is performed sufficiently, the erasing rate is constant regardless of the erasing power. Therefore, a difference ΔE _i in the erasing rate between adjacent test write sectors is obtained.

Next, the arithmetic section 24 calculates the difference ΔE _i in the erasure rate between adjacent test write sectors by the following equation (S 42).

ΔE _i = E _i-1 −E _i (i = 2 to J) (3) Next, the arithmetic unit 24 substitutes 2 for i (S43), and determines the difference between the erasure rates ΔE _i and a predetermined value. The value is compared with the value ΔE _min (S44).
If ΔE _i is larger than ΔE _min (S44, ΔE _i > Δ
E _min ), i + 1 is substituted for i (S45), and step S
Returning to step 44, the process is repeated. If ΔE _i is equal to or less than ΔE _min (S44, ΔE _i ≦ ΔE _min ), the DC erase power Pe _tmp corresponding to the test write sector is calculated by the following equation.

Pe _tmp = Pe _min + ΔPe × (i−1) (4) The Pe _tmp thus obtained is the minimum erasing power required for DC erasing the 11T repetitive signal. However, when information is actually recorded, especially when overwriting is performed, erasing and recording are performed simultaneously,
With the power Pe _tmp determined by the equation (4), the erasure becomes insufficient. Therefore, a value obtained by correcting this Pe _tmp is set as a Pe value at the time of normal recording. According to experiments performed by the applicant,
For some types of disks, the result of multiplying the constant γ _Pe in Pe _tmp was the closest to the optimum Pe value, and for other types of disks, the value obtained by adding the constant γ _Pe in Pe _tmp was the closest to the optimum Pe value. Therefore, the set value Pe _set of Pe may be calculated using the following equation (5) or equation (6).

[0111] _{Pe set = Pe tmp × γ Pe} (γ Pe ≧ 1) ... (5) Pe set = Pe tmp + γ Pe (γ Pe ≧ 0) ... (6) Therefore, for example, the formula (5) from the Pe setpoint Pe _set
Is obtained as in the following equation (S46).

[0112] _{Pe set = {Pe min + ΔPe} × (i-1)} × γ Pe ... (7) calculating unit 24 calculates a set value Pe _{The set} of Pe with (7).

Referring again to the flowchart shown in FIG.
Return. Next, the recording data control unit 21 sets the recording data as
3B and 11T repeats shown in FIG.
A pattern consisting of a return pattern and a synchronization pattern (test
Test pattern generation so that
Outputs a command signal to the circuit 13 and the recording pulse generation circuit 5
(S4). Then, the parameter setting unit 22
And the maximum value Pp of the normal recording as the parameter value Pp_maxTo
And set Pe as Pe obtained in step S3. _setTo
Set Ttop and Tmp as standard values Ttop_stdand
Tmp_stdAfter setting (S5), the test rule for Tcl
The site is executed (S6).

FIG. 6 is a flowchart for explaining the processing of step S6 in FIG. 4 in more detail. First,
The minimum value Tcl _min is set to Tcl (S61). The access control unit 23 issues a command to each driver of the thread and the radial actuator to cause the laser beam to access a predetermined sector L (S62). When it is confirmed that the laser beam has accessed the predetermined sector L,
The test pattern 2 set as the print data in step S4 is recorded with the parameters set in step S5. At this time, the minimum value of Tcl, Tcl _min
Then, recording is performed while increasing by ΔTcl for each test write sector (S63). The Tcl value at this time can be expressed by the following equation.

Tcl = Tcl _min + ΔTcl × (i−1) (i = 1 to J) (8) Next, the access control unit 23 again issues a command to the sled and the radial actuator, and outputs a predetermined sector L with a laser beam. (S64), and the test pattern recorded on the phase change recording disk 1 is reproduced. The arithmetic unit 24 calculates the average center level I11 of the 11T reproduction signal for each test write sector based on the synchronization signal detection signal from the reproduction data detection circuit 11 and the output from the A / D conversion circuit 17.
obtains an average center level I3a _i of the reproduced signal a _i and 3T,
And based on the output from the synchronization signal detection signal and the A / D conversion circuit 18 from the reproduced data detection circuit 11 calculates an average amplitude I11 _i of 11T signal every test write sectors (S65). Then, the arithmetic unit 24 calculates the asymmetry ASYM _i for each test write sector by the following equation (S
66).

ASYM _i = (I11a _i −I3a _i ) / I11 _i (9) The asymmetry ASYM _i and Tcl calculated in this manner
According to the experiment conducted by the present applicant, it has been found that the relationship has substantially linearity as shown in the graph of FIG. Therefore, when linearly approximated using the least square method or the like the relationship between Ashinmentori ASYM _i and Tcl, can be expressed by the following equation (S67).

ASYM _i = Tcl × α _Tcl −β _Tcl (10) Then, the arithmetic unit 24 determines from equation (9) that the asymmetry is 0.
A Tcl value Tcl ₀ is calculated (S68).

Tcl ₀ = β _Tcl / α _Tcl (11) According to the experimental results of the present applicant, it has been found that the optimum Tcl value is slightly higher than Tcl ₀ , and that in some discs, is close to the result obtained by multiplying the Tcl ₀ phrase constant gamma _Tcl most optimum Tcl value, results in a disk obtained by adding the Tcl ₀ phrase constant gamma _Tcl in other types was close to the most optimal Tcl value. Therefore, the operation unit 2
4 calculates the set value of Tcl by one of the following equations (12) and (13) (S69).

Tcl _set = Tcl ₀ × γ _Tcl (γ _Tcl ≧ 1) (12) Tcl _set = Tcl ₀ + γ _Tcl (γ _Tcl ≧ 0) (13) Returning to the description of the flowchart shown in FIG. 4 again. next,
The parameter setting unit 22 sets the maximum value Pp _max for normal recording as the parameter value Pp, sets Pe _set obtained in step S3 as Pe, sets the standard value Tmp _std as Tmp, and sets the standard value Tmp _std as Tcl value in step S6. After setting the Tcl _set obtained in (S7), a test write for Ttop is executed (S8).

FIG. 7 is a flowchart for explaining the processing of step S8 in FIG. 4 in more detail. First,
A minimum value Ttop _min is set to Ttop (S81). The access control unit 23 issues a command to each driver of the thread and the radial actuator to cause the laser beam to access a predetermined sector M (S82). When it is confirmed that the laser beam has accessed the predetermined sector M, the test pattern 2 set as the recording data in step S4 is recorded with the parameters set in step S7. At this time, recording is performed on the sector M at Ttop _min , which is the minimum value of Ttop, and recording is performed while increasing by ΔTtop for each test write sector (S83). The Ttop value at this time can be expressed by the following equation.

Ttop = Ttop_min+ ΔTtop × (i−1) (i = 1 to J) (14) Next, the access control unit 23 again sets the thread and the radio
Issues a command to the AL actuator to set the laser beam
(S84), and the phase change recording disk is accessed.
The test pattern recorded in step 1 is reproduced. Calculation
The section 24 receives a synchronization signal detection signal from the reproduction data detection circuit 11.
Test based on the signal and the output from the A / D conversion circuit 17
Average center level I of 11T reproduced signal for each write sector
11a_iAnd 3T reproduced signal average center level I3a_iAnd
And a synchronization signal detection from the reproduction data detection circuit 11.
Based on the output signal and the output from the A / D conversion circuit 18,
The average amplitude I11 of the reproduced signal of 11T for each write sector
_iIs measured (S85). Then, the calculation unit 24 calculates
Asymmetry ASYM per test write sector by _iTo
It is calculated (S86).

ASYM _i = (I11a _i −I3a _i ) / I11 _i (15) The asymmetry ASYM _i and Ttop thus calculated
According to the experiment conducted by the present applicant, it has been found that the relationship has substantially linearity as shown in the graph of FIG. Then, if the relationship between the asymmetry ASYM _i and Ttop is linearly approximated using the least squares method or the like, it can be expressed as the following equation (S87).

ASYM_i= Ttop × α_Ttop−β_Ttop (16) Then, the arithmetic unit 24 calculates the asymmetry from the expression (16).
Ttop value which becomes 0 Ttop ₀Is calculated (S88).

Ttop ₀ = β _Ttop / α _Ttop (17) According to the experimental results of the present applicant, the optimum Ttop value is Ttop _0.
It is with Ttop ₀ in the disk in most optimal Ttop close to values, other types result obtained by multiplying the Ttop ₀ phrase constant gamma _Ttop in slightly higher value as it has been found comprised certain disc than The result of adding the constant γ _Ttop was closest to the optimum Ttop value. Therefore, the calculation unit 24 calculates the set value of Ttop by using either the following equation (18) or (19) (S89).

Ttop _set = Ttop ₀ × γ _Ttop (γ _Ttop ≧ 1) (18) Ttop _set = Ttop ₀ + γ _Ttop (γ _Ttop ≧ 0) (19) Returning to the description of the flowchart shown in FIG. 4 again. next,
The parameter setting unit 22 sets the maximum value Pp _max of normal recording as the parameter value Pp, sets Pe _set obtained in step S3 as Pe, sets Ttop _set obtained in step S8 as Ttop, and sets Tcl After setting Tcl _set obtained in step S6 as a value (S
9), execute a test write for Tmp (S1)
0).

FIG. 8 is a flowchart for explaining the processing of step S10 in FIG. 4 in more detail. First, a minimum value Tmp _min is set to Tmp (S101).
The access control unit 23 issues a command to each driver of the thread and the radial actuator to cause the laser beam to access a predetermined sector Q (S102). When it is confirmed that the laser beam has accessed the predetermined sector Q, the test pattern 2 set as the recording data in step S4 is recorded with the parameters set in step S9. At this time, recording is performed on the sector Q at Tmp _min , which is the minimum value of Tmp, and recording is performed while increasing by ΔTmp for each test write sector (S103). The Tmp value at this time can be expressed by the following equation.

Tmp = Tmp _min + ΔTmp × (i−1) (i = 1 to J) (20) Next, the access control unit 23 again issues a command to the sled and the radial actuator to change the laser beam to the predetermined sector Q. (S104), and the test pattern recorded on the phase change recording disk 1 is reproduced. The arithmetic unit 24 calculates the average center level I of the 11T reproduced signal for each test write sector based on the synchronization signal detection signal from the reproduced data detection circuit 11 and the output from the A / D conversion circuit 17.
11a _i and an average center level I3a _i of the 3T reproduction signal are obtained. Further, based on the synchronization signal detection signal from the reproduction data detection circuit 11 and the output from the A / D conversion circuit 18, 11Ti is obtained for each test write sector. Average amplitude I11 of the reproduced signal of
_i is obtained (S105). The arithmetic unit 24 calculates the asymmetry ASYM _i for each test write sectors by the following equation (S106).

ASYM _i = (I11a _i −I3a _i ) / I11 _i (21) The asymmetry ASYM _i and Tmp calculated in this way
According to the experiment conducted by the present applicant, it has been found that, as shown in the graph of FIG. Therefore, asymmentary ASYM _i
When the relationship between Tmp and Tmp is approximated by two straight lines using the least squares method or the like, it can be expressed as the following equation (S10)
7).

ASYM _i = −Tmp × α1 _Tmp + β1 _Tmp (i = 1 to H) (22) ASYM _i = Tmp × α2 _Tmp −β2 _Tmp (i = H + 1 to J) (23) Equation (22) and (23) calculating the Tmp _c is a Tmp of intersection of the two straight lines from the equation becomes as follows.

Tmp _c = (β1 _Tmp + β2 _Tmp ) / (α1 _Tmp + α2 _Tmp ) (24) According to the experimental results of the applicant, in a certain kind of disc, there is an intersection Tmp _c between these two straight lines. The result of multiplying by the constant γ _Tmp was closest to the optimum Tmp value, and in the other types of discs, the result of adding Tmp _{c to a} certain constant γ _Tmp was closest to the optimum Tmp value. Therefore, the calculation unit 24 calculates the set value of Tmp by the following equations (25) and (26) (S109).

Tmp _set = Tmp _c × γ _Tmp (γ _Tmp ≦ 1) (25) Tmp _set = Tmp _c + γ _Tmp (γ _Tmp ≦ 0) (26) The description returns to the flowchart shown in FIG. 4 again. next,
The parameter setting unit 22 sets Pe _set obtained in step S3 as the parameter value Pe, sets Ttop _set obtained in step S8 as Ttop, and sets Tmp
Is _set as Tmp _set obtained in step S10,
After setting the Tcl _set obtained in step S6 as the Tcl value (S11), a test write for Pp is executed (S12).

FIG. 9 is a flowchart for explaining the processing in step S12 in FIG. 4 in more detail. First, the maximum value Pp _max is set to Pp (S121). The access control unit 23 issues a command to each driver of the thread and the radial actuator to cause the laser beam to access a predetermined sector R (S122). When it is confirmed that the laser beam has accessed the predetermined sector R, the test pattern 2 set as the recording data in step S4 is recorded with the parameters set in step S11. At this time, recording is performed on the sector R with Pp _max , which is the maximum value of Pp, and ΔPp
The recording is performed while decreasing the recording speed (S123). The Pp value at this time can be expressed by the following equation.

Pp = Pp_max-ΔPp × (i−1) (i = 1 to J) (27) Next, the access control unit 23 again executes
Issues a command to the AL actuator to set the laser beam
(S124), and the phase change recording directory is accessed.
The test pattern recorded on the disc 1 is reproduced. Performance
The calculation unit 24 detects a synchronization signal from the reproduction data detection circuit 11.
Based on the signal and the output from the A / D conversion circuit 17,
Average center level of 11T reproduced signal for each write sector
Le I11a_iAnd the average center level I3a of the 3T reproduced signal_iAnd
And a synchronization signal detection from the reproduction data detection circuit 11.
Based on the output signal and the output from the A / D conversion circuit 18,
The average amplitude I11 of the reproduced signal of 11T for each write sector
_iIs obtained (S125). Then, the calculation unit 24 calculates
Asymmetry ASYM per test write sector by _iTo
It is calculated (S126).

ASYM _i = (I11a _i −I3a _i ) / I11 _i (28) The relationship between the asymmetry ASYM _i and Pp calculated as described above is shown in FIG. As shown in the graph of FIG.
Then, if the relationship between the asymmetry ASYM _i and Pp is linearly approximated using the least squares method or the like, it can be expressed as the following equation (S127).

ASYM _i = Pp × α _Pp −β _Pp (29) Then, the arithmetic unit 24 calculates a Pp value Pp _{0 at} which the asymmetry becomes 0 from the equation (29) (S128).

Pp ₀ = β _Pp / α _Pp (30) According to the experimental results of the present applicant, it has been found that the optimum Pp value is slightly higher than Pp ₀ , and in some discs, the Pp ₀ phrase constant gamma _Pp and close to the result obtained by multiplying the most optimum Pp value, results in a disk obtained by adding the Pp ₀ phrase constant gamma _Pp in other types was close to the most optimum Pp value. Therefore, the arithmetic unit 24 calculates
The set value of Pp is calculated by one of the following equations (31) and (32) (S129).

Pp _set = Pp ₀ × γ _Pp (γ _Pp ≧ 1) (31) Pp _set = Pp ₀ + γ _Pp (γ _Pp ≧ 0) (32) Note that the output signal of the RF amplifier 7 is directly output to A / D-conversion may be performed, and the detection of the reproduction signal amplitude and the reproduction signal center level may be obtained by digital calculation. In this case, the processing part of the digital operation can be included in the recording / reproduction operation control circuit 12, and the size and cost of the optical disk recording / reproduction device can be reduced.

As described above, according to the optical disk recording / reproducing apparatus of the embodiment of the present invention, the recording / reproducing operation control circuit 12 sequentially determines the optimum values of the parameters defining the laser power and the pulse width of the laser light. Because it was set, it is possible to perform a highly accurate test light,
It has become possible to provide an optical disk recording / reproducing apparatus capable of performing highly reliable optical recording. Further, since the length of the test write sector can be adjusted, it is possible to realize a test write flexibly corresponding to the performance required of the optical disk recording / reproducing apparatus.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of an optical disc recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing two types of test patterns output from a test pattern generation circuit 13;

FIG. 3 is a block diagram showing a functional configuration of a recording / reproduction operation control circuit 12 shown in FIG.

FIG. 4 is a flowchart for explaining the entire test write operation in the present invention.

FIG. 5 is a flowchart for explaining the processing (Pe test write) of step S3 in FIG. 4 in further detail;

FIG. 6 is a flowchart for explaining the process (Tcl test write) in step S6 of FIG. 4 in more detail;

FIG. 7 is a flowchart for explaining the processing (Ttop test write) in step S8 of FIG. 4 in more detail;

FIG. 8 is a flowchart illustrating the process (Tmp test write) in step S10 of FIG. 4 in further detail.

FIG. 9 is a flowchart for explaining the processing (Pp test write) of step S12 in FIG. 4 in more detail;

FIG. 10 is a graph showing a relationship between each parameter and an erasure rate or asymmetry.

FIG. 11 is a block diagram showing a schematic configuration of a conventional information recording device using a phase change recording method.

FIG. 12 is a diagram for describing a case where information “1” is recorded in phase change recording.

FIG. 13 is a graph for explaining a relationship between each parameter and a jitter value.

FIG. 14 is a graph for explaining a relationship between each parameter and an asymmetry value.

FIG. 15 is a graph for explaining the influence of asymmetry values between parameters.

[Explanation of symbols]

1 phase change recording disk, 2 optical pickup, 3 spindle motor, 4 recording information processing circuit, 5 recording pulse generation circuit, 6 laser control circuit, 7 RF amplifier, 8
EQ circuit, 9 binarization circuit, 10 PLL circuit, 11
Reproduction data detection circuit, 12 recording / reproduction operation control circuit, 1
3 Test pattern generation circuit, 14 envelope detection circuit, 15 LPF, 16 difference circuit, 17, 18 A /
D conversion circuit, 21 recording data control unit, 22 parameter setting unit, 23 access control unit, 24 arithmetic unit, 25
Control unit.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D090 AA01 BB05 CC01 CC06 CC18 DD03 DD05 EE02 HH01 JJ12 KK04 KK05 5D119 AA23 AA26 BA01 BB04 DA01 DA07 FA05 HA19 HA50 HA52 HA60

Claims (33)

[Claims] 1. A pulse train corresponding to information to be recorded is converted into a pulse train finer than a minimum unit of information, the intensity of a laser beam is modulated by the fine pulse train, and the intensity-modulated laser beam is recorded on a medium. The light is focused on the layer and heated, and the optical state is changed according to the temperature distribution to record information.When reproducing, a relatively weak laser beam is focused on the recording layer, and the reflected light is reflected on the recording layer. An optical recording / reproducing apparatus for reproducing recorded information, comprising: a recording / reproducing operation control means for controlling a recording / reproducing operation based on an external operation request; and Access control means for moving the focused laser beam to a predetermined position; and at least a relatively long pattern repetition based on a command from the recording / reproduction operation control means. A test pattern generating means for selecting and outputting any one of a first predetermined pattern including at least a second predetermined pattern mainly including repetition of a relatively long pattern and a repetition of a relatively short pattern; Selecting means for selecting either a pulse train corresponding to the information to be recorded or an output signal from the test pattern generating means based on a command from the operation control means and outputting the selected signal to the recording pulse generating means; A first pulse train for raising the optical state of the recording layer to a first temperature or more that can change the optical state of the recording layer to the first state, based on a command from the means and the recording / reproducing operation control means; A second pulse train for keeping the temperature equal to or higher than the first temperature,
Recording pulse generating means for generating a third pulse train for cooling to a temperature equal to or higher than a second temperature which can be changed to a state below the first temperature, and the three types of pulses output from the recording pulse generating means A first power for heating the recording layer to the first temperature or higher based on the pulse train and a command from the recording / reproducing operation control unit; and a first power for heating the recording layer to the second temperature or higher and lower than the first temperature. Laser control means for modulating the power of the laser beam between a second power for heating the laser beam and a third power which does not change the state of the recording layer; and a reproduction signal for measuring the reproduction signal amplitude of the recorded pulse train. Amplitude measuring means, and a read signal center level measuring means for measuring a center level of a read signal of a recorded pulse train, wherein the recording / reproducing operation control means, prior to normal recording,
A transition is made to a test write mode for determining various parameters, a command is output to the access control means to move the laser beam spot to a predetermined position, and a predetermined test pattern is selected as the recording pulse generation means input signal. Thus, a command is output to the test pattern generation means and the selection means, the outputs of the reproduction signal amplitude measurement means and the reproduction signal center level measurement means are processed according to a predetermined algorithm, and the second power and the third power are measured. An optical recording / reproducing apparatus which operates to determine parameters in the order of the pulse width of the pulse train, the pulse width of the first pulse train, the pulse width of the second pulse train, and the first power. 2. The optical recording according to claim 1, wherein the relatively long pattern is sufficiently longer than a spot diameter of the laser beam, and the relatively short pattern is a shortest pattern of a modulation method used for recording information. Playback device. 3. The first and second predetermined patterns are:
The optical recording / reproducing apparatus according to claim 1, wherein the optical recording / reproducing apparatus includes a synchronization pattern at the time of normal recording. 4. The recording / reproducing operation control means according to claim 2, wherein:
In the power determination process, a command is output to the test pattern generation means and the selection means so that the first predetermined pattern is output to the recording pulse generation means, and a command is output for a first predetermined length. The first predetermined pattern is recorded with the parameter values of the following, and after the recording is completed, a command is outputted to the access control means so as to move the spot of the laser beam to a recording start position of the first predetermined pattern, and The first predetermined pattern is reproduced, and the output of the reproduction signal amplitude measuring means for each section of the second predetermined length shorter than the first length is stored as a first value. Outputting an instruction to the access control means to move a spot of the laser beam to a recording start position of the first predetermined pattern; A command is output to the recording pulse generating means and the laser control means so as to perform erasing with an unmodulated laser beam whose power increases or decreases for each section of the second length. Outputting an instruction to the access control means to move the spot of the laser beam to a recording start position of a predetermined pattern; reproducing the erased first predetermined pattern;
Storing, as a second value, the output of the reproduced signal amplitude measuring means for each section of a predetermined length, and erasing rate for each section of the second length from the first value and the second value. The optical recording / reproducing apparatus according to claim 1, wherein the optical recording / reproducing apparatus operates to determine the second power from this value. 5. The recording / reproducing operation control means obtains a difference in erasure rate between adjacent second length sections, and determines a minimum value of the intensity-unmodulated power at which the difference becomes equal to or less than a predetermined value. 5. The optical recording / reproducing apparatus according to claim 4, wherein the optical recording / reproducing apparatus operates so that the obtained value is corrected by performing a first predetermined operation, and the result is set as the set value of the second power. 6. The recording / reproducing operation control means, wherein:
In the process of determining the pulse width of the pulse train, a command is output to the test pattern generation means and the selection means so that the second predetermined pattern is output to the recording pulse generation means, and the laser beam is positioned at a predetermined position. And outputting a command to the access control means to move the spot, and recording the second predetermined pattern by increasing or decreasing the pulse width of the third pulse train for each section of the second length. Outputting a command to the recording pulse generating means and the laser control means, and instructing the access control means to move the spot of the laser beam to a recording start position of the second predetermined pattern after the end of the recording operation. Outputting the recorded second predetermined pattern;
2. The optical recording according to claim 1, wherein an output of said reproduction signal center level measuring means is stored for each section having a predetermined length, and the pulse width of said third pulse train is determined from said stored value. Playback device. 7. The recording / reproducing operation control means detects a portion corresponding to the relatively short pattern and a portion corresponding to a relatively long pattern from the stored value, and detects a section corresponding to the second length. The pulse width of the third pulse train in which the difference becomes 0 is obtained from the relationship between the result and the pulse width of the third pulse train when recording is performed, and the second value is added to the value. 7. The optical recording / reproducing apparatus according to claim 6, wherein said optical recording / reproducing apparatus operates so as to perform the predetermined calculation and correct the result to set the result as the set value of the pulse width of said third pulse train. 8. The recording / reproducing operation control means, wherein:
In the process of determining the pulse width of the pulse train, a command is output to the test pattern generation means and the selection means so that the second predetermined pattern is output to the recording pulse generation means, and the laser beam is positioned at a predetermined position. And outputting a command to the access control means to move the spot, and recording the second predetermined pattern by increasing or decreasing the pulse width of the third pulse train for each section of the second length. Output a command to the recording pulse generating means and the laser control means, and instruct the access control means to move the spot of the laser beam to a recording start position of the second predetermined pattern after the end of the recording operation. Is output, and the recorded second predetermined pattern is reproduced.
2. The optical recording according to claim 1, further comprising: storing an output of said reproduction signal center level measuring means for each section having a predetermined length, and determining a pulse width of said first pulse train from said stored value. Playback device. 9. The recording / reproducing operation control means detects a portion corresponding to the relatively short pattern and a portion corresponding to the relatively long pattern from the stored value, and detects a section corresponding to the second length. The first pulse train in which the difference is 0 is obtained from the relationship between the result and the pulse width of the first pulse train at the time of recording, and a third predetermined pulse train is obtained. The calculation is performed and the result is corrected.
9. The optical recording / reproducing apparatus according to claim 8, wherein the optical recording / reproducing apparatus operates so as to set the pulse width of the pulse train to the set value. 10. The recording / reproducing operation control means, wherein in the process of determining a pulse width of the second pulse train, the test pattern generation means and the test pattern generation means are arranged to output the second predetermined pattern to the recording pulse generation means. A command is output to the selection means, and a command is output to the access control means so as to move the spot of the laser beam to a predetermined position. The second predetermined pattern is provided for each section of the second length. A command is output to the recording pulse generating means and the laser control means so as to perform recording by increasing or decreasing the pulse width of the third pulse train, and after completion of the recording operation, the recording is performed at a recording start position of the second predetermined pattern. Outputting a command to the access control means to move the spot of the laser beam; reproducing the recorded second predetermined pattern; 2
2. The optical recording according to claim 1, wherein an output of the reproduction signal center level measuring means is stored for each section having a predetermined length of the predetermined length, and the pulse width of the second pulse train is determined from the stored value. Playback device. Wherein said recording operation control means, the Symbol
A portion corresponding to the relatively short pattern and a portion corresponding to the relatively long pattern were detected from the memorized values, the difference was obtained for each section of the second length, and the result and recording were performed. The relationship with the pulse width of the second pulse train at that time is approximated to two straight lines, the pulse width of the second pulse train at the intersection of the two straight lines is determined, and the value thereof is set to a fourth predetermined value. 11. The optical recording / reproducing apparatus according to claim 10, wherein the optical recording / reproducing apparatus operates so as to perform a calculation and correct the result to be a set value of a pulse width of the second pulse train. 12. The test pattern generating means and the selecting means so that the recording / reproducing operation controlling means outputs the second predetermined pattern to the recording pulse generating means in the first power determining process. And outputs a command to the access control means so as to move the spot of the laser beam to a predetermined position. The second predetermined pattern is output for each section of the second length. 1 is output to the recording pulse generating means and the laser control means so as to perform recording by increasing or decreasing the power of No. 1, and after the recording operation is completed, the laser beam spot is placed at the recording start position of the second predetermined pattern. Outputting a command to the access control means so as to move, reproducing the recorded second predetermined pattern;
2. The optical recording / reproducing apparatus according to claim 1, wherein an output of said reproduction signal center level measuring means for each section having a predetermined length is stored, and said first power is determined from said stored value. Wherein said recording operation control means, the Symbol
A portion corresponding to the relatively short pattern and a portion corresponding to the relatively long pattern were detected from the memorized values, the difference was obtained for each section of the second length, and the result and recording were performed. The first power at which the difference becomes 0 is obtained from the relationship with the first power at the time, and the value is corrected by performing a fifth predetermined operation, and the result is set to the set value of the first power. The optical recording / reproducing apparatus according to claim 12, which operates as follows. 14. The recording / reproducing operation control means, in the process of determining the second power, records the first pattern, and normally records the first and second powers at the time of recording the first pattern. And operating to output a command to the recording pulse generating means and the laser control means so that the pulse width of the first to third pulse trains is set to a standard value in normal recording. Or the optical recording / reproducing apparatus according to 4. 15. The recording / reproducing operation control means, in a process of determining a parameter other than the second power, sets a determined value for a parameter determined in a process before a process currently in progress. 15. The optical recording / reproducing apparatus according to claim 1, wherein the optical recording / reproducing apparatus operates to output a command to the recording pulse generating means and the laser control means to record the second pattern. 16. The reproduction signal amplitude measurement means, comprising: a high level envelope detection means for detecting a high level envelope of the relatively long pattern reproduction signal; and a low level envelope of the relatively long pattern reproduction signal. Low-level envelope detection means for detecting an envelope; difference means for obtaining a difference between outputs of the high-level and low-level envelope detection means; and A / D conversion means for A / D converting an output of the difference means. The optical recording / reproducing apparatus according to claim 1. 17. The reproduction signal center level measuring means,
A low-pass filter having a lower cut-off frequency than a frequency corresponding to the relatively long pattern; and an A / D converter for A / D-converting an output of the low-pass filter.
The optical recording / reproducing apparatus according to claim 1, further comprising: a D conversion unit. 18. A pulse train corresponding to information to be recorded is converted into a pulse train finer than the minimum unit of information, the intensity of the laser beam is modulated by the fine pulse train, and the intensity-modulated laser beam is applied to a recording layer on a medium. A test write method for an optical recording / reproducing apparatus for recording information by changing the optical state according to the temperature distribution and heating the light, wherein the fine pulse train at least sets the optical state of the recording layer to the first state. A first pulse train for raising the temperature to or above a first temperature that can be changed to the state described above, a second pulse train for keeping the temperature of the recording layer at or above the first temperature, A third pulse train for cooling the target state to a second state and lower than the first temperature at a second temperature or higher, wherein the intensity of the laser beam is at least the first temperature. As described above, the first power for heating the recording layer, the second power for heating the recording layer to the second temperature or more and less than the first temperature, and the third power where the state of the recording layer does not change. Power, a first step of determining the second power, a second step of determining a pulse width of the third pulse train, and a pulse width of the first pulse train. And a fourth step of determining a pulse width of the second pulse train; and a fifth step of determining the first power.
Test light method. 19. The first step comprises: recording a first predetermined pattern; erasing a recorded mark with a laser beam which is not intensity-modulated; and reproducing a reproduction signal amplitude when reproducing the mark portion before and after erasure. 19. The test write method according to claim 18, further comprising: determining a ratio of the first power to the second power, and determining the second power from the result. 20. The step of determining the second power includes the step of recording a first predetermined pattern in a section of a first length, and the step of recording a recorded mark having a second length shorter than the first length. Erasing with a non-intensity-modulated laser beam whose power increases or decreases in each section, and an erasing rate for each section of the second length is obtained, and a difference between erasing rates in adjacent sections is equal to or less than a predetermined value. And determining the second power by correcting the power value by a first operation to determine the second power.
Test light method described. 21. The test light method according to claim 19, wherein the first predetermined pattern includes a repetition of a pattern sufficiently longer than at least a spot diameter of a focused laser beam. 22. The second step, wherein a second predetermined pattern mainly including repetition of a relatively short pattern and repetition of a relatively long pattern is recorded, and a center level of the amplitude of the reproduction signal of the short pattern is recorded. 20. The test write method according to claim 18, further comprising: detecting a central level of the amplitude of the reproduced signal having the long pattern and determining a pulse width of the third pulse train based on the detection result. 23. The step of determining a pulse width of the third pulse train, wherein the step of determining the pulse width of the third pulse train comprises the step of
Increasing or decreasing the pulse width of the pulse train of
Recording a predetermined pattern of; and detecting, for each section of the second length, a center level of the amplitude of the reproduction signal of the short pattern and a center level of the amplitude of the reproduction signal of the long pattern, and determining a difference therebetween. Determining the pulse width of the third pulse train in which the difference in the center level is 0 from the relationship between the pulse width of the third pulse train and the difference in the center level, and calculating the result in a second operation Determining the pulse width of the third pulse train by correcting the pulse width of the third pulse train. 24. The third step, wherein a second predetermined pattern mainly including a repetition of a relatively short pattern and a repetition of a relatively long pattern is recorded, and a center level of an amplitude of a reproduced signal of the short pattern is recorded. 19. The test write method according to claim 18, further comprising: detecting a center level of the amplitude of the reproduced signal having the long pattern and determining a pulse width of the first pulse train based on the detection result. 25. The step of determining a pulse width of the first pulse train, wherein the step of determining the pulse width of the first pulse train is performed for each of the second length sections.
Increasing or decreasing the pulse width of the pulse train of
Recording a predetermined pattern of; and detecting, for each section of the second length, a center level of the amplitude of the reproduction signal of the short pattern and a center level of the amplitude of the reproduction signal of the long pattern, and determining a difference therebetween. Determining the pulse width of the first pulse train in which the difference in the center level is 0 from the relationship between the pulse width of the first pulse train and the difference in the center level, and calculating the result as a third operation Determining the pulse width of the first pulse train by correcting the pulse width of the first pulse train. 26. The fourth step, wherein a second predetermined pattern mainly including repetition of a relatively short pattern and repetition of a relatively long pattern is recorded, and a center level of an amplitude of a reproduced signal of the short pattern is recorded. 19. The test write method according to claim 18, further comprising: detecting a central level of the amplitude of the reproduced signal of the long pattern and determining a pulse width of the second pulse train based on the detection result. 27. The step of determining a pulse width of the second pulse train, wherein the step of determining the pulse width of the second pulse train comprises the step of:
Increasing or decreasing the pulse width of the pulse train of
Recording the predetermined pattern, and detecting a difference between the center level of the amplitude of the reproduction signal of the short pattern and the center level of the amplitude of the reproduction signal of the long pattern for each section of the second length, and Determining the relationship between the pulse width of the second pulse train and the difference between the center levels with two straight lines, and calculating the pulse width of the third pulse train corresponding to the intersection of the two straight lines. And determining the pulse of the second pulse train by correcting the result by a fourth operation.
Test light method described. 28. The fifth step, wherein a second predetermined pattern mainly including repetition of a relatively short pattern and repetition of a relatively long pattern is recorded, and a center level of an amplitude of a reproduced signal of the short pattern is recorded. And detecting a center level of the amplitude of the reproduction signal of the long pattern, and determining the first power based on the detection result.
The test light method according to claim 18. 29. The step of determining the first power comprises: increasing or decreasing the first power for each section of the second length to record the second predetermined pattern; Detecting a difference between the center level of the amplitude of the reproduced signal of the short pattern and the center level of the amplitude of the reproduced signal of the long pattern for each section of the second length; From the relationship with the difference of the center level,
Determining the first power at which the difference between the center levels is 0, and determining the first power by correcting the result by a fifth operation.
Test light method described. 30. Among the second predetermined patterns, the relatively short pattern is the shortest pattern of a modulation method used when recording information, and the relatively long pattern is the focused laser beam. The test light method according to any one of claims 22 to 29, wherein the pattern is a pattern sufficiently longer than the spot diameter. 31. The first and second predetermined patterns include a synchronization signal for recording information.
30. The test light method according to any one of items 29. 32. The first step, wherein the first and second powers are maximum powers in normal recording, the pulse widths of the first to third pulse trains are standard values in normal recording, 3. The method of claim 1, further comprising the step of recording a first pattern to determine said second power.
0. The test write method according to any one of the above items. 33. The step of determining a parameter other than the second power uses the determined value for a parameter determined in a step other than the step currently in progress, and uses the determined value for an undetermined parameter. 30. The test write method according to claim 18, wherein the second pattern is recorded using a value adopted in the step of determining a second power.