JP2003346341A - Method and apparatus for controlling recording laser power - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method of recording laser power to find accurately an optimal recording laser power value at short times. <P>SOLUTION: The method is constituted of a process to read information of a plurality of line speeds from a recordable optical recording medium corresponding to a plurality of line speeds; a process to decide the prescribed line speed information of a faster side in the read plurality pieces of line speed information; a process to time-share the recording laser at intervals of prescribed time as a trial and to record the signals of a low frequency component and high-frequency components by a plurality of different respective recording power values and to a process to reproduce the recorded signals; to compare values focused on amplitude of reproducing signals corresponding to low frequency component pulses at intervals of prescribed time with values focused on amplitude of reproducing signals corresponding to high-frequency component pulses by intervals of prescribed time, and a process to decide the actual recording laser power value on the basis of the comparison result. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital versatile disc (hereinafter referred to as a DVD), such as DVD-R and DVD-R.
The present invention relates to a control method of a recording laser power value for irradiating a recordable optical disk which controls recording power and erasing power with an organic dye medium such as W, DVD + RW, DVR blue or a phase change medium, and a recording laser power control device.

[0002]

2. Description of the Related Art At present, CD-RW, DVD-R and DVD-
2. Description of the Related Art There is known an apparatus that performs recording and reproduction on an organic dye medium such as RW, DVD + RW, and DVR blue or a phase change medium. In such an apparatus, the quality of the recording depends on the physical characteristics and optical characteristics of the phase change medium, the pickup and the laser wavelength for performing the recording to be used, and it is necessary to control the recording laser power to an optimum value. . For this purpose, it is necessary to know whether the power set by the apparatus is the power actually emitted, that is, the current actual power.

A conventional calibration method for finding an optimum power in an organic dye medium or a phase change medium is described in, for example, a patent publication (Japanese Patent No. 3159454) and a prior application (Japanese Patent Application No. 2001-250150) and drawings. ). Here, FIG.
As shown in FIG. 4A, a recording signal c shown in FIG. 4D is applied to a dedicated track 3 provided on the DVD-RW as shown in FIG.
Based on the LPP (Land Pre-pit) sync (synchronization signal) a, a predetermined time (hereinafter referred to as STEP) as shown in FIG.
That. The recording is performed while changing the recording signal c in each case.

FIG. 1 shows a specific example of the recording signal c. As can be seen from FIG. 1, the recording signal c1 does not use the recording signal c of 8-16 modulation, which is a normal signal to be recorded on a DVD, but uses only 11T and 3T, and makes the 11T pulse section three times 3T. The pulse period is formed 10 times, again 11 times, 3 times, and 3T times, 12 times. As a result, "H" section of 11T pulse → 11T × 3 = 33T “L” section of 11T pulse → 11T × 3 = 33T “H” section of 3T pulse → 3T × 11 = 33T “L” section of 3T pulse → As in the case of 3T × 11 = 33T, the number of times of the “H” level and the “L” level in each pulse section is the same, in other words, the duty ratio is 50%
That is. T is the channel frequency.

[0005] Thereafter, the signal obtained by reading and reproducing the track 2 on the DVD-RW and removing the DC component of the obtained 8-16 modulated RF signal (by an AC coupling capacitor) is shown in FIG.
(E) is like the AC-coupled reproduced signal g, and the relationship of the center position of the amplitude of the 3T signal with respect to the center of the 11T signal amplitude of the AC-coupled reproduced signal g (hereinafter, this relationship is called asymmetry) almost coincides. Calibration was performed using the value (B4) of the recording laser power b at that time as the optimum recording laser power value. A, B, C in FIG.
FIG. 6 shows the eye pattern of the portion. As can be seen from FIG. 6, the portion B4 can be called the optimum power value. Actually, this point is determined based on data such as coincidence with the minimum point of the jitter of the reproduction signal.

[0006]

However, in such a medium used as an organic dye or a phase change recording layer, particularly in a phase change medium, the relationship between the center of the amplitude of the 3T signal and the center of the amplitude of the 3T signal is considered. The rate of change of the (deviation amount) (hereinafter, this relationship is referred to as asymmetry) with respect to the recording power may depend on the linear velocity. If the rate of change is large, detection is possible, but depending on the linear velocity, detection is not possible. There is a problem that it is difficult.

Generally, in a recording apparatus, when the apparatus is manufactured and shipped from a factory, the recording laser power is adjusted. Therefore, the target power and the output power coincide with each other. Since power fluctuates due to dust or the like adhering to the system, it is necessary to measure the actual power actually emitted as a first step.

Accordingly, it is an object of the present invention to provide a recording laser power control method and a recording laser power control device for obtaining an optimum recording laser power value with high accuracy in a short time.

[0009]

In order to solve the above-mentioned problems, the present invention provides a recording laser power control apparatus having the following configuration. According to the present invention, a step of reading a plurality of pieces of linear velocity information from a recordable optical recording medium corresponding to a plurality of linear velocities, and the faster predetermined linear velocity information among the read plurality of pieces of linear velocity information Deciding a step, time-divisionally multiplexing a recording laser at predetermined time intervals for a signal of a low frequency component and a high frequency component, recording each with a plurality of different recording power values, and reproducing the recorded signal. The value of the amplitude center of the reproduction signal corresponding to the signal of the low frequency component pulse at each predetermined time, and the value of the amplitude center of the reproduction signal corresponding to the signal of the high frequency component pulse at each predetermined time. A recording laser power control method including a comparing step and a step of determining an actual recording laser power value based on the comparison result is provided.

According to the present invention, a step of reading recording conditions including recording linear velocity information from a recordable optical recording medium;
When the recording condition including the read recording linear velocity information does not satisfy a predetermined condition, a step of determining a linear velocity higher than the recording condition including the recording linear velocity information, and a step of setting the higher linear velocity. A step of recording the signal of the low frequency component and the high frequency component on a test basis by time-division of the recording laser at predetermined time intervals, and recording the signals at a plurality of different recording power values, and reproducing the recorded signal; Comparing the value of the amplitude center of the reproduction signal corresponding to the signal of the pulse at each predetermined time with the value of the amplitude center of the reproduction signal corresponding to the signal of the high frequency component pulse at the predetermined time, Determining the actual recording laser power value based on the comparison result.

According to the present invention, there is further provided a recording / reproducing apparatus for recording / reproducing information on / from a recordable optical recording medium on which recording conditions corresponding to a plurality of linear velocities are recorded. Reading means for reading the read recording conditions, determining means for determining the faster predetermined linear velocity information among the read linear velocity information, and test-recording a signal of a low frequency component and a high frequency component. Test recording means for time-dividing the laser at predetermined time intervals and recording at a plurality of different recording power values, means for measuring the amplitude of a reproduction signal corresponding to the signal of the low frequency component pulse, and the high frequency component Means for measuring the amplitude of the reproduction signal corresponding to the pulse signal; and reproducing the recorded signal, and measuring the amplitude of the reproduction signal corresponding to the low frequency component pulse signal. Comparing means for comparing the value at each predetermined time with the value at each predetermined time at the center of the amplitude of the reproduced signal corresponding to the signal of the high frequency component pulse, and calculating the actual recording laser power value based on the comparison result. A recording laser power control device comprising a laser power determining means for determining is provided.

Further, according to the present invention, in a recording / reproducing apparatus for recording / reproducing on a recordable optical recording medium on which a recording condition corresponding to a linear velocity is recorded, the read recording condition satisfies a predetermined condition. Means for determining whether to
Determining means for determining a linear velocity higher than the recording condition including the recording linear velocity information when the result of the determination does not satisfy the condition;
Test recording means for time-divisionally recording a low frequency component and a high frequency component signal by a recording laser at predetermined time intervals, and recording the signals at a plurality of different recording power values, respectively, corresponding to the low frequency component pulse signal; Means for measuring the amplitude of the reproduction signal, means for measuring the amplitude of the reproduction signal corresponding to the signal of the high frequency component pulse, and the reproduction signal for reproducing the recorded signal and corresponding to the signal of the low frequency component pulse The value of the amplitude center of each of the predetermined time,
The recording means comprises a comparing means for comparing the value of the amplitude center of the reproduction signal corresponding to the signal of the high frequency component pulse at each of the predetermined times, and a laser power determining means for determining an actual recording laser power value based on the comparison result. A laser power controller is provided.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings using preferred embodiments.

The present invention will be described with reference to FIGS. Recordable / reproducible DV for implementing power control method of the present invention
FIG. 2 shows a main part of the D-RW recorder. During test recording, the DVD-RW 1 is rotated by the spindle motor 7, and the rotation is controlled by the servo circuit 10.
At this time, the pickup 6 is controlled by the servo circuit 10 at a position corresponding to the track 2. The calibration recording signal generation circuit 17 (test recording signal) is controlled by the control signal 1 from the controller 16 to control the recording signal c.
1 is generated and input to the recording amplifier 4 via the changeover switch 18 controlled by the changeover signal r.

The recording signal c1 is stored in advance in the ROM or the like in the controller 16 without depending on the recording signal generating circuit 17 for calibration, and is read out as appropriate. May be given.

Then, the laser diode of the pickup 6 is driven, and the recording and erasing laser power b at this time is supplied via a controller (servo-mechanical control microcomputer) 16 and a D / A converter 14, which will be described later. This is performed by variably controlling the recording amplifier 4 according to the recording laser power control signal mp and the erasing laser power control signal me as shown in FIG.

At the time of reproducing the signal recorded in the test recording,
The recording / playback switch 8 is switched to the PB side, and the pickup 6
Is amplified by the reproducing amplifier 9 and its R
Output the F signal to the decoder. On the other hand, the RF signal output from the reproduction amplifier 9 is generated from an address signal and a wobble signal from a decoder not described in detail for any of the peak detection circuit 12, the bottom detection circuit 13, and the average value detection circuit 19 including the sample and hold circuit. The signal is sampled and held by using the switching signal 20 which is the timing signal thus obtained, and the signal after the sample holding is switched by the switching circuit 21.
Switch with. The switched signal is input to the controller 16 via the A / D converter 15 based on the timing signal of the reproduction signal from the decoder, and is used for calculating an optimum power value described later. The peak detection circuit 12, the bottom detection circuit 13, and the average value detection circuit 19 correspond to the signal obtained by averaging the peak and bottom signals of the 11T signal and the 3T signal of FIG. 4 and FIG. 6 through the LPF. The circuit for averaging is 3T, 4T or 5T depending on the setting of the LPF.
It is designed so that the frequency of T can be averaged.

As a recording signal for test recording, the recording signal c1 shown in FIG. 1 is similarly used. FIG. 4 shows a diagram corresponding to FIG. The recording is performed in a test recording area (Power Calibration Area) on the inner circumference of the DVD-RW. FIG. 4 (b)
In accordance with a timing signal of an LPP (land pre-pit) formed as a pre-pit address on a land on the outer peripheral side of a groove which is a data recording area in accordance with the DVD-RW standard, a method shown in FIG. Recording is performed with the recording power being increased so that the value of the ratio of the recording power to the erasing power ε is kept constant and the recording power is increased.

As can be seen from FIG. 1, the recording signal c1 is D
Instead of using the VD 8/16 modulated recording signal c, 1
Using only 1T and 3T, 3 times 11T pulse section, 3T
10 times pulse section, 3 times 11 pulse section again, 3T
The pulse section is formed in a repeated pattern of 12 times, a total of 132T periods. As a result, "H" section of 11T pulse → 11T × 3 = 33T “L” section of 11T pulse → 11T × 3 = 33T “H” section of 3T pulse → 3T × 11 = 33T “L” section of 3T pulse → 3T × 11 = 33T, so that the number of “H” level and “L” level in each pulse section is set to be the same, and the duty ratio is set to 50%
To avoid the influence of the DC component of the signal component.

A control algorithm for reproducing the recording signal to calculate an optimum recording power will be described.

Move to the place where the test recording was first performed,
The LPP timing signal obtained from the decoder of the target LPP address is detected, and the peak value of the 11T signal and the bottom value of the 11T signal sampled and held by the timing signal corresponding to each recording position are measured. Calculate the center value between the value and the bottom value. Next, the average value detection output, which is the center of the 3T signal, is measured, and the average value detection output is compared with the center value of the peak value and the bottom value.
The asymmetry is obtained by dividing the difference between the average value detection output with respect to the center value of the peak value and the bottom value by the peak-to-peak value of the peak value and the bottom value.

The asymmetry is 0% or a value close to 0% (under a predetermined condition, the DVD-RW has a value of -5% to + 5%).
Although the standard value is determined as 15%, the target value differs depending on the pickup used in the actual apparatus and the recording waveform (strategy) which is the recording condition. Is determined, and the optimum value measured in the ROM of the recording device or the manufacturing process is recorded in the EEPROM. ), The output power when the target value is compared with the target value recorded in the apparatus becomes the optimum recording power value.

Here, the DVD-RW medium has a unique ID of the medium, a recommended recording power to be recorded recommended by a manufacturer of the medium, a ratio ε of a recommended recording power and an erasing power for determining an erasing power, When the leading pulse width of the recording power, which is the recording waveform, the multi-pulse width of the middle area, the cooling pulse width for determining the trailing edge pulse or the trailing edge pulse width (strategy), and the asymmetry value are present. Has a recommended asymmetry value recorded on the medium together with the linear velocity information. At present, there is only a 1 × speed standard, but when a high speed standardization such as 2 × speed or 4 × speed is performed, a recommended value corresponding to each double speed value is similarly recorded on the medium. Information having the same meaning as in DVD-R and DVD + RW is recorded on a medium.

Therefore, at the time of developing and manufacturing the device, the medium is evaluated, and if it is determined that the recommended value recorded on the medium can be used as the recommended value in the device as well,
Alternatively, if it is determined that the medium can be used by offsetting this value, the unique ID of the medium can be used as it is. Or ROM or EEP of the device with offset
It is stored in the ROM. If there is no asymmetry value, the target asymmetry value corresponding to the optimum power is measured and stored in the ROM or EEPROM of the apparatus.

Then, when the medium is evaluated and it is determined that the recommended value recorded on the medium is not useful for the apparatus, the value is not used for reference, and the specific I / O of the medium is not used.
D and the above recommended values are stored in the ROM or EE
It is stored in the PROM.

FIG. 3 shows the actual asymmetry characteristics of the DVD-RW for 1 × speed. The 1 × speed (hereinafter referred to as 1X) is a linear velocity of 3.49 m / s. When a 1X DVD-RW disc was recorded under the 1X recording condition, the 1X DVD-RW disc was recorded at 1.5X compared to the case where the inclination indicating the dependence on the power on the horizontal axis was small.
It can be seen that, when recording is performed under the recording conditions described above, the slope indicating the dependence on the power on the horizontal axis increases. The reason for this is related to the recording mechanism of the phase change medium. When the recording speed is high, when a small mark such as 3T is formed, not only the length direction but also the width direction of the long mark such as 11T is used in the width direction. On the other hand, when the recording linear velocity is low, the thermal diffusion time for forming a mark is short enough for a short mark such as 3T, and the width direction does not change much for a long mark such as 11T. It is considered that a mark of the shape is formed.

FIG. 5 shows the asymmetry characteristics of the double-speed DVD-RW under development. The double speed (hereinafter referred to as 2X) is a linear velocity of 6.98 m / s. 2X
The discs correspond to 1X and 2X, and the recommended values corresponding to the respective speeds are described on the discs.
When a 2X DVD-RW disc was recorded under the 1X recording condition under the 1X recording condition, the 2X DVD-RW disc was recorded under the 2X recording condition as compared with the case where the gradient indicating the dependence on the power on the horizontal axis was very small. In the case of recording, it can be seen that the gradient indicating the dependence on the power on the horizontal axis becomes large. The reason is the same as in the previous period, and it is considered that similar results can be obtained with media of other standards without being limited to the results of this experiment.

What can be determined from this result is that 1 in FIG.
In X, when recording and reproduction are performed at 1X, the asymmetry value becomes 0% when the recording power is around 13 mW, and the jitter also becomes the minimum point (not shown), but the asymmetry gradient when the power is changed is very small. Small, accurate detection of this asymmetry value increases costs by adding a circuit scale, such as increasing the resolution of the A / D converter, and eliminates the need to increase recording and measurement time to increase measurement accuracy. It requires an extra time, which is not desirable.
On the other hand, if the power is determined with low measurement accuracy,
If recording / reproducing is performed by another device, a problem occurs in recording / reproducing compatibility.

On the other hand, when recording / reproducing at 1.5X, the asymmetry value becomes 0% near the recording power of 13 mW which is almost the same power, and although not shown, the jitter also becomes the minimum point. The asymmetry gradient at this time is very large, and it is easy to accurately detect this asymmetry value.

That is, the 1X medium is dedicated to 1X, and the recommended value of 1.5X or the like is not described on the medium, but the apparatus must experimentally recognize the performance of the 1X medium in advance. For example, the target power can be clearly known from the asymmetry value without knowing the value of the power that the device actually emits.

Similarly, in 2X of FIG. 5, when recording and reproduction are performed at 1X, the asymmetry value becomes 2% when the recording power is around 13 mW, and the jitter also becomes the minimum point (not shown). The asymmetry slope is very small when the measurement is performed. To accurately detect the asymmetry value, the cost is increased by adding a circuit scale such as increasing the resolution of the A / D converter, and the recording is performed to increase the measurement accuracy. In addition, an unnecessary increase in time such as an increase in measurement time is required, which is not desirable. On the other hand, if the power is determined with the measurement accuracy being low, a problem occurs in the recording / reproducing compatibility when recording / reproducing with another device.

On the other hand, when recording and reproducing at 2 ×, the asymmetry value becomes 2% near the recording power of 13 mW, which is almost the same power, and the jitter also becomes the minimum point (not shown). Has a very large inclination of asymmetry, and it is easy to accurately detect this asymmetry value.

That is, when recording on a medium that supports both 1X and 2X recording, the optimum power is obtained from the asymmetry value at 2X, and the difference between the obtained optimum power and the recommended power recorded on the medium is obtained. Is calculated, the value of the power actually emitted can be obtained. For example, when recording is performed at 1X with the present medium, the target power is calculated from the difference between the recommended power value of 1X recorded on the medium and the previous value. Can be obtained.

This concept is not limited to the numerical values of 1X and 2X, but results of optimal asymmetry measurement with high detection sensitivity (slope) in a medium corresponding to a plurality of recordings having different linear velocities (double speed). This means that the power actually emitted can be obtained with high accuracy based on the linear velocity at which can be obtained, and that recording at other velocities can be supported.

The processing in the actual apparatus will be described below.

(First Embodiment) As described above, on a medium corresponding to the DVD-RW of 1 × or 2 × speed in this embodiment, the ID unique to the medium and the recording recommended by the medium manufacturer should be recorded. Determine the recommended recording power, the ratio ε of the recommended recording power and the erasing power for determining the erasing power, the leading pulse width of the recording power that is the recording waveform that is the recording condition, the multi-pulse width in the middle area, and the trailing pulse. Of the cooling pulse width or the pulse width (strategy) at the rear end, and if there is an asymmetry value, the recommended asymmetry value is recorded on the medium together with the linear velocity information. At the time of development and manufacture of the device, the medium is evaluated, and if it can be determined that the recommended value recorded on this medium can be used as a recommended value in the device as well, or if it is possible to offset this value and use it If it can be determined, the unique I of the medium
D can be used as it is. Alternatively, it is stored in the ROM or the EEPROM of the apparatus together with the offset. If there is no asymmetry value, the target asymmetry value corresponding to the optimum power is measured and the ROM or EE of the device is measured.
It is stored in the PROM. Then, when the medium is evaluated, and it is determined that the recommended value recorded on the medium is not useful for the device, the value is not used for reference, and the unique ID of the medium and the respective recommended values described above are used. The RO of the device
(1) At startup, disc type is discriminated, and if the disc type is recognizable, the disc is moved to the disc management area, and the unique ID of the medium and The recommended recording power to be recorded recommended by the manufacturer of the medium, the ratio ε of the recommended recording power and the erasing power for determining the erasing power, the leading pulse width of the recording power that is the recording waveform that is the recording condition, and the multi-pulse in the middle area The linear velocity information is read based on the width, the cooling pulse width for determining the pulse at the rear end, or the pulse width (strategy) at the rear end, and the recommended asymmetry value when there is an asymmetry value.

(2) The unique ID of this medium is the RO of the apparatus.
M or ID stored in EEPROM
Based on the ID, information on a management area of a usable medium is set in a recording system circuit of the apparatus. (3) Next, when it is read from the information in the management area that the medium corresponds to a plurality of linear velocities as the linear velocity information, the optimum linear velocity information stored in the ROM or the EEPROM of the apparatus is selected. Then, the selected information is set in the recording system circuit. (4) The above series of test recordings is performed at the set linear velocity, and the current power is determined accurately from the asymmetry data having a high inclination. For example, a test recording is performed on a data medium whose power is 13 mW from the information of the management area and which is recognized as an effective ID in accordance with the experimental data at 2% asymmetry, and the set power of the apparatus is 15 mW.
When the result of asymmetry 2% is obtained, it can be determined that the amount of light emitted from the objective lens of the optical system of the apparatus has decreased for some reason, and the subsequent power setting is 15 mW−13 mW = 2 mW. Is added and output. In this way, even when the medium is to be recorded at a linear velocity lower than the linear velocity at which the test recording was performed, the above-mentioned offset value is added to the information of the management area at the linear velocity, whereby the asymmetry is obtained. Even in the case where the slope of the characteristic is gentle and detection is difficult, accurate power setting can be performed.

(Second Embodiment) Next, the DV in this embodiment
For a medium corresponding only to 1 × speed of D-RW, a unique ID of the medium, a recommended recording power to be recorded recommended by a manufacturer of the medium, a ratio ε of a recommended recording power and an erasing power for determining an erasing power, When the leading pulse width of the recording power, which is the recording waveform, the multi-pulse width of the middle area, the cooling pulse width for determining the trailing edge pulse or the trailing edge pulse width (strategy), and the asymmetry value are present. Has a recommended asymmetry value recorded on the medium. At the time of developing and manufacturing the equipment, evaluate the media,
If it can be determined that the recommended value recorded on this medium can be used as a recommended value in the device as well, or if it can be determined that it can be used by offsetting this value, the unique ID of the medium Can be used as is. Or device ROM or EEPROM with offset
To memorize it. If there is no asymmetry value, the target asymmetry value corresponding to the optimum power is measured and stored in the ROM or EEPROM of the apparatus. Then, when the medium is evaluated, and it is determined that the recommended value recorded on the medium is not useful for the device, the value is not used for reference, and the unique ID of the medium and the respective recommended values described above are used. (1) At startup, disc type is discriminated, and if the disc type is recognizable, the disc type is moved to the disc management area, ID, the recommended recording power to be recorded recommended by the manufacturer of the medium, the ratio ε between the recommended recording power and the erasing power for determining the erasing power, the leading pulse width of the recording power that is the recording waveform as the recording condition, and the middle area. Multi-pulse width, cooling pulse width to determine the trailing edge pulse or trailing edge pulse width (strategy), recommended asymmetry if there is an asymmetry value Over value is read out the linear velocity information.

(2) The unique ID of this medium is the RO of the apparatus.
M or ID stored in EEPROM
Based on the ID, information on a management area of a usable medium is set in a recording system circuit of the apparatus. (3) Next, when the medium corresponding to one linear velocity is read out from the information of the management area as the linear velocity information, the optimum test recording to be performed in the ROM or EEPROM of the apparatus should be performed. The linear velocity information (1.5 times speed) is read, and the linear velocity information is set in the recording system circuit. (4) The above-described series of test recordings is performed at the set linear velocity (1.5 times speed), and the current power is accurately determined from the asymmetry data having a high inclination. For example, a test recording is performed on a data medium whose power is 13 mW from the information of the management area and which is recognized as an effective ID in agreement with the experimental data at 0% asymmetry. %, It can be determined that the amount of light emitted from the objective lens of the optical system of the apparatus has decreased for some reason. Therefore, the subsequent power setting is performed using an offset value of 15 mW−13 mW = 2 mW. Thereafter, it is added and output. Next, normal recording is performed by returning the linear velocity of the medium to 1 × speed.

(Third Embodiment) FIG. 7 is a cross-sectional view of FIG.
This is a characteristic in which the asymmetry of the 3T signal is shown for the 1T signal, while the asymmetry of the 3T signal and the 4T signal is plotted for the 11T signal. When such a reproduction signal is binarized and converted into digital data, the simple condition for minimizing the reproduction jitter is that it is desirable that the binarization level of each T be the same.
When the asymmetry level of each T becomes the same value, the optimum power with the best jitter can be determined. Based on this relationship, FIG. 7 shows that the point where 3T and 4T, which have a particularly large influence on the jitter, intersect has the optimum power. In this concept, test recording is similarly performed using signals including 3T and 4T, and 3T and 4T are recorded.
Is determined, and the power at this intersection is set to almost the optimum power (it can be managed regardless of the value).
Also in this method, the optimum power recorded on the medium is stored in ROM or EEPROM as in the above two embodiments.
Compared with the value stored in M, the difference between the set power at the intersection and the power described on the medium is used as an offset value for recording at other linear velocities. Also in the method of finding the intersection, it is desirable that this asymmetry be obtained with a high inclination, and this can be realized by appropriately selecting the linear velocity for test recording as in the above embodiment.

The asymmetry described in the text is a positional relationship between the center of the amplitude of the low-frequency signal and the center of the high-frequency signal component in the reproduced signal. As long as the relationship is defined, even if the signal is digitally processed in the DC state, the C-cut using a capacitor and the position of the 11T signal with respect to the center of the entire signal are defined. The same holds true for β in the β method described in the DVD-R and DVD-RW standards and for the name of symmetry. Here, 3T, 4T, 11T
However, the T value of the low-frequency signal component and the high-frequency signal component is appropriately changed depending on the modulation method.

In this embodiment, the characteristics of a eutectic phase-change material such as a DVD-RW, particularly using a material such as AgInAsTe, have been described as an example. However, a compound (single-crystal) material using a material such as GeAsTe is used. The same tendency is observed in the characteristics of the phase change material of (crystal system), and the same method can be used when similar results can be obtained by using an organic dye material.

[0043]

As described above, according to the present invention, when the optimum value of the recording and erasing powers is detected, the gradient of the asymmetry value with respect to the power is increased by setting the optimum linear velocity and performing test recording. The detection accuracy of the optimum recording power has been improved, and it is not necessary to determine the power using test recording with low accuracy at other linear velocities, and the optimum power can be obtained in a short time. By
It is possible to maintain compatibility between devices and manufacturers during recording / reproduction and contribute to market development.

[Brief description of the drawings]

FIG. 1 is a waveform diagram of a recording signal for test recording.

FIG. 2 is a main block diagram of a DVD-RW recorder as one embodiment of the apparatus of the present invention.

FIG. 3 is an asymmetry characteristic diagram of a DVD-RW (1X medium) for 1 × speed.

FIG. 4 is a time chart showing one embodiment of the method of the present invention.

FIG. 5 is an asymmetry characteristic diagram of a double-speed DVD-RW (2X medium).

FIG. 6 is an explanatory diagram of an eye pattern of a DC-coupled reproduced signal in the case of FIG. 4;

FIG. 7 shows a 3T signal and a 4T signal in a DVD-RW for 2 × speed.
FIG. 9 is an asymmetry characteristic diagram of a T signal.

[Explanation of symbols]

1 ... DVD-RW 2. Calibration area 3 ... Truck 4: Recording amplifier 6 ... Pickup 7 ... Spindle motor 8 Recording / playback switch 9 ... Reproduction amplifier 10 ... servo circuit 12 ... Peak detection circuit 13 ... Bottom detection circuit 14 ... D / A converter 15 A / D converter 16 ... Controller 17. Calibration recording signal generation circuit 18. Changeover switch 19. Average value detection circuit 20: Switching signal 21 ... Switching circuit 22 ... Switch a ... LPP sink b: Recording laser power c: Recording signal c1 ... recording signal g: playback signal l ... Control signal me: Erase laser power control signal mp: Recording laser power control signal n: Recording / playback switching signal o: Recording signal switching control signal q: Integral output PREC: Recording power r switching signal

Claims (6)

[Claims] A step of reading a plurality of pieces of linear velocity information from a recordable optical recording medium corresponding to a plurality of pieces of linear velocity; Deciding a step; time-divisionally multiplexing a recording laser at predetermined time intervals for a signal of a low frequency component and a high frequency component to record at a plurality of different recording power values; and reproducing the recorded signal. The value of the amplitude center of the reproduction signal corresponding to the signal of the low frequency component pulse at each predetermined time, and the value of the amplitude center of the reproduction signal corresponding to the signal of the high frequency component pulse at each predetermined time. A method for controlling a recording laser power, comprising: a step of comparing; and a step of determining an actual recording laser power value based on a result of the comparison. Reading a recording condition including recording linear velocity information from a recordable optical recording medium; and, when the recording condition including the read recording linear velocity information does not satisfy a predetermined condition, recording the recording linear velocity. Determining a linear velocity faster than the recording conditions including information; setting the faster linear velocity; and time-divisionally setting the recording laser at predetermined time intervals to test low frequency component and high frequency component signals. Recording at a plurality of different recording power values, respectively, reproducing the recorded signal, the value of the amplitude center of the reproduced signal corresponding to the signal of the low frequency component pulse at each of the predetermined times, and the high frequency component Comparing the value of the amplitude center of the reproduction signal corresponding to the pulse signal at each of the predetermined times, and determining the actual recording laser power value based on the comparison result. The method of recording laser power, wherein. 3. The recording laser power control method according to claim 2, further comprising the step of setting a linear velocity higher than a linear velocity condition for recording on said optical recording medium. 4. A recording / reproducing apparatus for recording / reproducing information on / from a recordable optical recording medium on which recording conditions corresponding to a plurality of linear velocities are recorded, wherein recording is performed from said optical recording medium corresponding to a plurality of linear velocities. Reading means for reading conditions; determining means for determining predetermined faster linear velocity information among the plurality of read linear velocity information; and a recording laser for testing low frequency component and high frequency component signals. Test recording means for performing time division at predetermined time intervals and recording with a plurality of different recording power values, means for measuring the amplitude of a reproduction signal corresponding to the signal of the low frequency component pulse, and Means for measuring the amplitude of the reproduced signal corresponding to the signal; and reproducing the recorded signal, and at each of the predetermined times of the amplitude center of the reproduced signal corresponding to the low frequency component pulse signal. Comparing means for comparing each value with the value of the amplitude center of the reproduced signal corresponding to the signal of the high frequency component pulse at each of the predetermined times; and determining the actual recording laser power value based on the comparison result. Means for controlling recording laser power. 5. A recording / reproducing apparatus for recording / reproducing information on / from a recordable optical recording medium on which recording conditions corresponding to a linear velocity have been recorded, wherein it is determined whether the read recording condition satisfies a predetermined condition. Determination means; determination means for determining a linear velocity higher than the recording condition including the recording linear velocity information when the result of the determination is not satisfied; and testing the recording laser with low frequency component and high frequency component signals. Test recording means for performing time division at predetermined time intervals and recording with a plurality of different recording power values, means for measuring the amplitude of a reproduction signal corresponding to the signal of the low frequency component pulse, and Means for measuring the amplitude of a reproduced signal corresponding to the signal; reproducing the recorded signal; and the predetermined center of the amplitude center of the reproduced signal corresponding to the low frequency component pulse signal. Comparing means for comparing the value of each interval with the value of the amplitude center of the reproduction signal corresponding to the signal of the high frequency component pulse at each of the predetermined times; and a laser power for determining an actual recording laser power value based on the comparison result. A control device for recording laser power, comprising: a determination unit. 6. A recording laser power control apparatus according to claim 5, wherein said determining means includes means for determining a linear velocity higher than a linear velocity condition of a medium to be recorded.