JP2000137918A - Recording method and recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely determine the optimum recording power value by OPC (optimum power control) by performing OPC from jitters with a larger change even in proximity to the optimum recording power. SOLUTION: This recording method is such that it has a recording power correcting area for obtaining the optimum recording power value, that, at the time of recording data on a reloadable optical recording medium, trial writing is done by recording marks while changing the recording power on the recording power correcting area, that the jitter of the marks so recorded on the correcting area is measured, and that the recording of the data is carried out by determining the recording power for which the mark with the smallest jitter is recorded as the optimum recording power value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recording on an optical recording medium and a recording / reproducing apparatus. More specifically, the present invention relates to a recording method for an optical recording medium and a recording / reproducing apparatus for determining an optimum recording power by measuring a jitter of a mark recorded in a recording power calibration area.

[0002]

2. Description of the Related Art In recent years, in the field of data recording, research on an optical recording system has been advanced. The optical recording system has a recording density that is at least one digit higher than that of the magnetic recording system, and has various advantages such as being compatible with a read-only type, a write-once type, and a rewritable type. As described above, the optical recording system is considered to be a recording system capable of realizing an inexpensive large-capacity file, and has a wide range of applications from industrial use to consumer use.

[0003] Among the above-mentioned optical recording systems, a magneto-optical disk, a phase-change optical disk, and the like can be cited as those corresponding to a rewritable memory mode.
In a magneto-optical disk, a recording layer made of a magnetic material is irradiated with a high-power laser, and the coercive force of the recording layer is reduced by raising the temperature of the recording layer partially above the Curie point or the temperature compensation point. An information signal is recorded by changing the magnetization direction of the recording layer by applying a recording magnetic field, and the information signal is magnetically read. On the other hand, a phase-change optical disk includes a recording layer made of a phase-change material in which a phase change between a crystalline state and an amorphous state occurs reversibly, and the recording layer is heated by irradiation with laser light or the like,
Information is recorded and erased by causing a phase change in the recording layer, and an information signal is optically read.

When recording and / or reproducing information on or from such a rewritable optical disk, in order to record a high-quality signal, test writing is performed before recording an actual signal, and then a test writing portion is written. And the optimum recording power must be determined by examining the signal quality.

[0005] This test writing area is called a recording power calibration area.
It is provided on the disk for each format such as RW. A series of operations for determining the optimum recording power is referred to as Optimum Power Control (OPC: Optim Po
wer control).

Normally, OPC is performed in the following procedure. First, while changing the laser power in several steps,
Write a test signal to the recording power calibration area. Next, the test signal is reproduced, and among the reproduced signals, a power for recording an area where the recording signal is reproduced with the highest quality is obtained, and the power at that time is set as an optimum recording power.

There are various methods for evaluating the quality of a reproduced signal. As an example, a method of performing the evaluation using a modulation degree calculated from the maximum value and the minimum value of an RF signal will be described.

First, a test signal recorded at each recording power in the recording power calibration area is reproduced, and its maximum value I
_{From the max} and the minimum value I _{min, the} modulation factor m is calculated by the following equation.

M = (I _max -I _min ) / I _max Next, γ is calculated from the obtained modulation degree m and the recording power P at that time by the following equation.

When γ = (dm / dP) × (P / m), the modulation degree m and γ change with respect to the recording power as shown in FIG. Then, the recording power P _target when γ = γ _target is obtained from FIG. Then, a value obtained by multiplying the recording power P _target by the coefficient k is determined as the optimum recording power value P _opt .

P _opt = k × P _target By performing actual recording in the program area using the optimum recording power value P _opt determined in this way, a good reproduction signal quality can be obtained.

[0012]

However, in the conventional recording / reproducing apparatus which performs OPC by the method of determining the optimum recording power from the change in the modulation degree as described above, the OPC is performed in a low recording power area where recording can be started. Is going. For this reason, the conventional recording / reproducing apparatus has a problem that a change in the modulation degree may have large unevenness in the circumference due to the influence of skew, defocus, or the like, and the accuracy of the optimum recording power value is reduced.

Therefore, if the OPC is performed around the optimum recording power in which the variation in the modulation does not easily cause the unevenness in the circumference, the influence of the unevenness in the circumference is reduced and the optimum power can be determined with high accuracy.

However, near the optimum recording power, a large change in the modulation degree in the circumference hardly occurs, but the change amount of the modulation degree is small, so that γ is calculated from the modulation degree and OPC is calculated as described above. If so, the optimum recording power cannot be determined with high accuracy.

The present invention has been proposed in view of such a conventional situation. A recording method in which OPC is performed from a jitter having a large amount of change even near the optimum recording power, and the optimum recording power value by the OPC can be determined accurately. And a recording / reproducing apparatus.

[0016]

According to the recording method of the present invention, a recording power calibration area for obtaining an optimum recording power value is provided. Change the recording power in the calibration area, record the mark, perform test writing, measure the jitter of the mark recorded in the recording power calibration area, and optimize the recording power where the mark with the minimum jitter was recorded The recording of the data is performed as a recording power value.

In the recording method according to the present invention as described above, since the optimum recording power value is obtained from the jitter of the mark, the optimum recording power value can be obtained with high accuracy without being affected by in-periphery unevenness.

The recording method of the present invention has a recording power calibration area for obtaining an optimum recording power value, and when recording data on a rewritable optical recording medium, the recording power calibration area is recorded in the recording power calibration area. The mark was recorded and the test write was performed, and the jitter of one edge and the jitter of the other edge of the mark recorded in the recording power calibration area were measured, and the jitter of one edge of the mark was measured. The recording of the data is performed with the recording power at which a mark having the same jitter as that of the other edge is recorded or the power obtained by adding or subtracting a predetermined value from the recording power as the optimum recording power value.

In the recording method according to the present invention as described above, the recording power at which a mark in which the jitter of one edge of the mark is equal to the jitter of the other edge is recorded, or a predetermined value is added to or subtracted from the recording power. Since the optimum recording power value is used as the optimum recording power value, the optimum recording power value can be accurately obtained without being affected by skew, defocus, and the like, and the time for obtaining the optimum recording power value can be reduced.

The recording / reproducing apparatus of the present invention is a recording / reproducing apparatus for recording and / or reproducing data on / from a rewritable optical recording medium having a recording power calibration area for obtaining an optimum recording power value. Recording means for recording a mark on a recording medium, and a jitter measuring means for measuring the jitter of the mark recorded by the recording means, the recording means, in the recording power calibration area of the optical recording medium, the recording power The mark was recorded and the test writing was performed, the jitter of the mark was measured by the jitter measuring means, and the recording power at which the mark with the minimum jitter was recorded was determined as the optimum recording power value, and the data of the data was recorded. The recording is performed.

In the recording / reproducing apparatus according to the present invention as described above, since the optimum recording power value is obtained from the jitter of the mark, the optimum recording power value can be obtained accurately without being affected by skew or defocus.

The recording / reproducing apparatus of the present invention is a recording / reproducing apparatus for recording and / or reproducing data on / from a rewritable optical recording medium having a recording power calibration area for obtaining an optimum recording power value. Recording means for recording a mark on a recording medium, and a jitter measuring means for measuring the jitter of the mark recorded by the recording means, the recording means, in the recording power calibration area of the optical recording medium, the recording power The mark is recorded and the test writing is performed by changing the mark, and the jitter measuring means uses the jitter of one edge of the mark recorded in the recording power calibration area,
The jitter of the other edge is measured, and the recording power at which the mark at which the jitter at one edge of the mark is equal to the jitter at the other edge is recorded or the power obtained by adding or subtracting a predetermined value to the recording power is optimally recorded. The data is recorded as a power value.

In the recording / reproducing apparatus according to the present invention as described above, the recording power at which a mark in which the jitter of one edge of the mark is equal to the jitter of the other edge, or a predetermined value is set to the recording power. Since the adjusted power is used as the optimum recording power value, the optimum recording power value can be accurately obtained without being affected by skew, defocus, and the like, and the time for obtaining the optimum recording power value can be shortened.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described. In the present embodiment,
As an optical recording medium, a phase-change type optical disc, which records or reads a signal by irradiating a laser beam to a light transmission layer formed on a support having an information signal portion, will be described as an example. However, it goes without saying that the present invention is not limited to this.

FIG. 1 is a block diagram showing an example of the configuration of the recording / reproducing apparatus according to the present embodiment. The recording / reproducing apparatus 1 includes a motor 2 for driving the optical disk 10 to rotate, an optical pickup 3 for writing or reading signals to / from the optical disk 10, a servo signal processing system 4 for controlling the position of the optical pickup 3, and an optical pickup. 3, an RF signal processing system 5 for processing an information signal read from the optical disk 10.

The signal output from the optical pickup 3 is input to a servo signal processing system 4 and an RF signal processing system 5.
The signal S1 input to the servo signal processing system 4 is subjected to an operation for controlling the position of the optical pickup 3. And
The signal S2 calculated by the servo signal processing system 4 is input to the optical pickup 3 again for controlling the position of the optical pickup 3. Then, the servo control of the optical pickup 3 is performed based on the signal S2. On the other hand, the signal S3 input to the RF signal processing system 5 performs decoding and encoding of the read data.

As shown in FIG. 2, the RF signal processing system 5 includes a jitter measuring system 20 for measuring jitter.
And a processing system 21 for performing other processing. Here, the jitter measurement system 20 will be described.

The jitter measuring system 20 includes an equalizer 2
2, a slicer 23, and a PLL (phase-locked loop)
It comprises a circuit 24 and a jitter measuring device 25. The RF signal S3 read from the optical disk 10 passes through the equalizer 22, and the signal S4 passing through the equalizer 22
Is binarized by the slicer 23. One signal S5 of the binarized RF signal is sent to the PLL circuit 24, and the other signal S6 is sent to the jitter measuring device 25. In the PLL circuit 24, a clock is generated from one signal S5 of the binarized RF signal. Then, the generated clock S
7 is sent to the jitter measuring device 25 and the jitter measuring device 25
Then, the jitter is measured from the clock S7 and the other signal S6 of the binarized RF signal.

FIG. 3 is a diagram showing the RF signal waveform and the RF signal waveform binarized by the slicer 23 in correspondence with the recording marks. 3 shows a clock generated by the PLL circuit 24 from one of the binarized RF signals.

FIG. 4 is a graph showing the relationship between the recording power and the jitter. FIG. 4 shows that the jitter changes in accordance with the recording power and takes a minimum value at a certain recording power value. At this time, test writing needs to be performed around the recording power at which the jitter is minimized. For example,
In FIG. 4, the minimum value of jitter may be obtained by performing test writing between 12.5 mW and 14.5 mW. As described above, in order to know the optimum recording power, it is necessary to perform test writing until the jitter exceeds the recording power at which the jitter becomes minimum and the jitter increases again.

An edge of the recording mark on the side where the mark starts to be recorded (hereinafter, referred to as a rear edge).
And the edge at the end of the recording of the mark (hereinafter referred to as the leading edge) is measured, and the optimum recording power can be known by comparing the measured jitters.

As shown in FIG. 3, the leading edge of the recording mark corresponds to the falling edge of the data, and the trailing edge corresponds to the rising edge of the data. In this method, the jitter is measured for each of the leading edge and the trailing edge of the recording mark, and the measured values are compared to determine the optimum recording power at which the jitter is minimized.

The basic configuration of the signal processing system for measuring the jitter at the leading edge and the trailing edge of the recording mark is almost the same as the configuration of the signal processing system described above, and the description is omitted here.

FIG. 5 is a diagram showing the measurement results of the recording power and the jitter for the leading edge, the trailing edge and both edges of the recording mark. From FIG. 5, it can be seen that when the jitter of the leading edge and the jitter of the trailing edge are equal, the jitter of both edges is almost minimized.
As described above, when the recording power is equal to the jitter of the leading edge and the jitter of the trailing edge, the normal jitter is substantially minimized, and this recording power may be set as the optimum recording power.

In this method, when the jitters of the leading edge and the trailing edge are equal to each other, it is considered that the normal jitter is substantially minimized. Therefore, the recording power exceeds the recording power at which the jitter is minimized, and the jitter increases again. It is not necessary to perform the test writing until it is sufficient, and it is sufficient to perform the test writing up to the recording power at which the jitter of the leading edge is equal to the jitter of the trailing edge. For example, in FIG.
It is only necessary to perform the test writing from W for the first time until the recording power at which the jitters of the front edge and the rear edge are equal, that is, 13.5 mW.

In consideration of the offset and the like of the recording / reproducing apparatus, it is possible to perform data recording with the recording power obtained by adding or subtracting a predetermined value to the recording power at which the jitter of the leading edge and the trailing edge are equal, as the optimum recording power. preferable. The predetermined value is determined according to the standard of the recording / reproducing device or the optical recording medium.

As described above, by comparing the jitter of the leading edge and the jitter of the trailing edge, the optimum recording power can be accurately obtained. Further, in this method, it is only necessary to perform test writing up to the recording power at which the jitter of the leading edge and the jitter of the trailing edge are equal, so that the processing time of the OPC can be reduced and the space for the recording power calibration area to be used can be saved. Also becomes possible.

[0038]

According to the present invention, since the recording power at which the jitter is minimized is set as the optimum recording power value, the optimum recording power value by OPC can be determined accurately without being affected by skew, defocus and the like. .

Further, in the present invention, the recording power at which the jitter of the leading edge and the trailing edge is equal is set as the optimum recording power value. Therefore, it is possible to shorten the OPC processing time and save the recording power calibration area to be used. Will be possible.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a recording / reproducing apparatus according to the present invention.

FIG. 2 is a block diagram showing one configuration example of a jitter measurement system provided in the RF signal processing system of FIG.

FIG. 3 is a diagram showing an RF signal waveform and a binarized RF signal waveform in association with recording marks.

FIG. 4 is a diagram showing a relationship between recording power and jitter.

FIG. 5 is a diagram showing a relationship between a recording power and a jitter for a front edge, a rear edge, and both edges of a recording mark.

FIG. 6 is a diagram illustrating a relationship between recording power and modulation factors m and γ in conventional OPC.

[Explanation of symbols]

1 recording / reproducing device, 2 motor, 3 optical pickup, 4 servo signal processing system, 5 RF signal processing system,
10 optical disc, 20 jitter measuring system, 2
1, equalizer, 22 slicer, 23 PLL circuit, 24 jitter measuring instrument

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshihiro Akimoto 6-35 Kita Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) 5D090 BB04 CC01 CC04 CC18 DD03 DD05 EE02 GG27 HH01 JJ12 KK03

Claims (4)

[Claims] When recording data on a rewritable optical recording medium having a recording power calibration area for obtaining an optimum recording power value, a mark is recorded by changing recording power in the recording power calibration area. Perform a test write, measure the jitter of the mark recorded in the recording power calibration area, and record the data with the recording power at which the mark with the minimum jitter was recorded as the optimum recording power value. Characteristic recording method. 2. When recording data on a rewritable optical recording medium having a recording power calibration area for obtaining an optimum recording power value, a mark is recorded by changing recording power in the recording power calibration area. The jitter of one edge and the jitter of the other edge of the mark recorded in the recording power calibration area are measured, and the jitter of one edge of the mark and the jitter of the other edge of the mark are measured. A recording power on which a mark having a value equal to the recording power or a power obtained by adding or subtracting a predetermined value from the recording power is recorded as an optimum recording power value. 3. A recording / reproducing apparatus for recording and / or reproducing data on / from a rewritable optical recording medium having a recording power calibration area for finding an optimum recording power value, wherein a mark is recorded on the optical recording medium. Means, comprising: a jitter measuring means for measuring the jitter of the mark recorded by the recording means, the recording means, in the recording power calibration area of the optical recording medium, recording the mark by changing the recording power, Performing test writing, measuring the jitter of the mark with the jitter measuring means, and recording the data with the recording power at which the mark having the minimum jitter was recorded as the optimum recording power value. Recording and playback device. 4. A recording / reproducing apparatus for recording and / or reproducing data on / from a rewritable optical recording medium having a recording power calibration area for finding an optimum recording power value, wherein a mark is recorded on the optical recording medium. Means, comprising: a jitter measuring means for measuring the jitter of the mark recorded by the recording means, the recording means, in the recording power calibration area of the optical recording medium, recording the mark by changing the recording power, Perform test writing, and measure the jitter of one edge of the mark and the jitter and jitter of the other edge of the mark by the jitter measuring means, and determine the jitter of one edge of the mark and the jitter of the other edge. The recording power at which an equal mark is recorded or the power obtained by adding or subtracting a predetermined value to the recording power is defined as the optimum recording power value. Recording and reproducing apparatus, characterized in that for recording over data.