JP2008251078A - Recording power control method in optical disc apparatus - Google Patents

Abstract

An object of the present invention is to stabilize recording quality regardless of temperature changes.
A phase error amount of a recording signal is measured (S1), and a recording power is controlled (S4) based on a phase error amount (S2, S3) obtained by the measurement.
[Selection] Figure 2

Description

  The present invention relates to an optical disc apparatus for recording a data signal on an optical disc such as a CD (Compact Disc) and a DVD.

  Since the optical disk apparatus records or reproduces information by irradiating the optical disk with laser light, the intensity of the laser light irradiated on the optical disk is required to accurately record and reproduce information. It is necessary to keep the depth of pits formed on the optical disk constant.

  As a power control method during the recording operation of DVD ± R, a target β asymmetry value (hereinafter referred to as β value) is set in advance, and the β value is measured at the inner periphery of the optical disk at the start of recording, and the target recording power is It is set.

Also, during recording, the β value is continuously measured for each specific sector. If offset from the set target β value, the power correction value corresponding to the offset amount is added or subtracted. The recording power is adjusted.
JP 2002-150558 A JP 2005-92950 A

  However, the β value has a large variation in measured values depending on the temperature, and the power control is unstable at high and low temperatures. In particular, since all signal amplitudes up to 14T are affected, when the recording power is extremely off, the β value cannot be measured correctly and correct recording power correction cannot be performed.

  An object of the present invention is to provide a recording power control method that can correctly perform recording power correction even when thermal interference occurs under high and low temperature conditions.

  According to a first aspect of the present invention, there is provided a recording power control method in an optical disc apparatus, wherein the phase error amount of a recording signal is measured when controlling the recording power recorded on the optical disc by an optical pickup, and the phase error amount obtained by the measurement is obtained. The recording power is controlled based on this.

  According to a second aspect of the present invention, there is provided a recording power control method for an optical disc apparatus, wherein a phase error amount of a recording signal is measured when controlling a recording power to be recorded on an optical disc by an optical pickup, and a preset target phase error amount is calculated. The recording power is controlled based on a result of comparison with a phase error amount obtained by the measurement.

  In the recording power control method for an optical disc apparatus according to claim 3 of the present invention, a signal is recorded on the optical disc using a predetermined recording power when controlling the recording power to be recorded on the optical disc by an optical pickup. The recording power is controlled based on a result of measuring a phase error amount of the signal and comparing a preset target phase error amount with the phase error amount obtained by the measurement.

  According to a fourth aspect of the present invention, there is provided a recording power control method for an optical disc apparatus, wherein a signal is recorded on the optical disc using a predetermined recording power when the recording power to be recorded on the optical disc is controlled by an optical pickup. Based on the result of measuring the phase error amount of the signal and comparing the target phase error amount set in advance with the phase error amount obtained by the measurement, power correction for the difference between the target phase error amount and the measured phase error amount An amount is set, and the recording power is corrected by the power correction amount and recorded.

  According to a fifth aspect of the present invention, there is provided a recording power control method for an optical disk apparatus according to any one of the first to fourth aspects, wherein the phase error amount of the recording signal is measured by the EFM after a specified code space of the EFM signal. The phase of the designated code mark of the signal is measured.

  According to this configuration, the recording power is not controlled based on the β value as in the prior art, but the phase error is measured and the recording power is controlled based on the measured phase error. However, correct recording power correction can be performed.

Hereinafter, a recording power control method of the present invention will be described based on specific embodiments.
FIG. 1 shows an optical disk apparatus for implementing the recording power control method of the present invention.
An optical disc apparatus for reproducing a data signal recorded on an optical disc 1 such as a compact disc (Compact Disc), a DVD (Digital Versatile Disc), a Blu-ray Disc (Blu-ray Disc), etc., and recording the data signal. A spindle motor 2 having a detachable mechanism is provided. The optical disk 1 is fixed to the spindle motor 2 and the optical disk 1 is rotated. The spindle motor 2 is controlled by the spindle motor control circuit 3 to rotate the optical disc 1 at a desired rotation speed.

  An optical pickup 4 for irradiating the optical disk 1 with the laser beam LB to record a signal and irradiating the optical disk 1 with the laser beam LB to detect the reflected light has means for reproducing a data signal from the optical disk 1 and data. A means for recording a signal and a means for reproducing a servo control signal on the optical disc 1 are provided.

  The servo processor 5 transmits the rotation speed of the optical disc 1 to the spindle motor control circuit 3 according to the servo information on the optical disc by the servo control signal reproduced from the optical pickup 4, and the position of the optical pickup 4 from the servo information. Then, the angle, focus, etc. are transmitted to the optical pickup 4, and based on the information, the optical pickup 4 sets the position, angle, focus, etc. suitable for recording and reproduction of the data signal.

  The data signal reproduced by the optical pickup 4 is measured by the phase error measuring unit 7 between the respective signals, that is, the phase of the designated code mark of the EFM signal after the designated code space of the EFM signal. When the optical disc is a DVD as the designated code mark, any phase error of 3T to 14T is measured. For example, International Publication No. WO2002 / 084653 may be used for the phase error measuring device 7. The phase error value between the signals measured by the phase error measuring device 7 is calculated by the recording power controller 8 by calculating a difference between the target phase error between signals and the phase error between signals from the phase error measuring device 7, Calculate the required recording power correction amount. The target inter-signal phase error value and the recording power correction amount may be determined in advance.

  When recording a data signal on the optical disc 1, the laser drive circuit 9 records the signal on the optical disc 1 by the optical pickup 4 with the recording power corrected by the recording power controller 8.

The data reproduction signal reproduced by the optical pickup 4 is stored in the memory 10 as a data signal.
The phase error measuring device 7 and the recording power controller 8 are mainly composed of a microcomputer, and the configuration is shown in FIG.

  First, in step S1, the data signal recorded on the optical medium is reproduced by the optical pickup 4. A phase error value between target signals is measured by the phase error measuring device 7 from the reproduced data signal. As for the phase between signals to be measured, in the case of DVD, it is the phase of the signal signal and the mark signal of the 3T to 14T signals, or the phase of the mark signal and the signal signal, and may be all or a part of the phases.

  The recording power controller 8 is set with a target inter-signal phase and a target value of the inter-signal phase error value. The target value of the target phase error is also the phase error value between the signals of the signal signal and the mark signal between the signals, or the phase of the signal of the mark signal and the signal signal. A value calculated from the phase error value of the part may be used.

As shown in FIG. 3, the recording power controller 8 also stores the recording power correction amount for the difference between the target phase error value and the measured phase error value.
In step S2 following step S1, a difference amount is acquired from the phase error value measured by the recording power controller 8 and the set target phase error value.

In step S3, the recording power correction amount is determined from the set recording power correction table of FIG. 3 according to the difference amount obtained in step S2.
In step S4, a value obtained by adding the recording power correction amount determined in step S3 to the current recording power is newly set as the recording power, and the laser drive circuit 9 is instructed.

Thus, the phase error measuring device 7 and the recording power controller 8 execute Steps S1 to S4, and the laser driving circuit 9 newly sets the recording power to the optical pickup 4.
FIG. 4 shows details of the flowchart of FIG.

  In advance, the recording power controller 8 is set with a target phase error of the data signal and a target value of the phase error. The target data signal is a signal formed by a combination of a mark which is a low-reflectance area of an optical disk and a space which is a high-reflectance area in an arbitrary area recorded on the optical disk. For both spaces, the mark length or space length is classified, for example, as a 3T mark, according to the recording time unit T determined by the frequency performance of the optical disc apparatus. The phase error of the data signal is obtained by averaging the errors in the data signal with respect to the phase between the mark and the space or between the space and the mark.

  The phase error of the target signal is the phase error between the target mark and the space, or the front end side or the rear end side between the space and the mark. It may be a phase error, a phase error of all marks and spaces, or a part of phase errors.

  Also, the target value of the target phase error may be one phase error value on the front end side or rear end side of the phase error of each signal, and is calculated from all phase errors or a part of phase error values. It may be a value.

  In step S11, the data signal recorded on the optical disc 1 is reproduced by the optical pickup 4. A phase error measuring unit 7 measures a target phase error from the reproduced data signal.

  In step S12, the recording power controller 8 compares the phase error value obtained in step S11 with a preset target phase error value. If it is determined in step S12 that the comparison result is within the appropriate range, step S13 is executed to instruct the laser drive circuit 9 to use the current recording power without changing the recording power. To do.

  If it is determined in step S12 that the comparison result is outside the proper range, step S14 is executed to compare whether the measured phase error amount is smaller than the proper range amount of the target phase error amount.

  If it is determined in step S14 that the measured phase error amount is smaller than the appropriate range amount of the target phase error amount, step S15 is executed, based on the difference amount between the target phase error amount and the measured phase error amount. The correction amount is determined from the correction power table, and then step S16 is executed. In step S16, the correction amount determined in step S15 is added to the current recording power to correct the recording power, which is newly set as the recording power, and commanded to the laser drive circuit 9.

  If it is determined in step S14 that the measured phase error amount is not smaller than the appropriate range amount of the target phase error amount, step S17 is executed to obtain a difference amount between the target phase error amount and the measured phase error amount. Based on the correction power table, the correction amount is determined, and then step S18 is executed. In step S18, the recording power is corrected by subtracting the correction amount determined in step S17 from the current recording power, and this is newly set as the recording power and commanded to the laser drive circuit 9.

  When the target signal is a signal on the front end side of the phase error of the 3T space 3T mark, the target signal is compared with the signal on the front end side of the 3T space 3T mark from the phase error measuring device 7, and the target 3T space 3T. If the phase is shifted to the smaller side than the phase error of the mark, the recording power is added. If the phase is shifted to the larger side, the recording power is subtracted.

  FIG. 5 shows measured values of the relationship between CATS PI Error, 3T phase shift, and β with the recording power as the horizontal axis. The 3T phase shift, which is the amount of 3T phase error from the phase error measuring device 7, is expressed as β It can be seen that there is a linear phase relationship with respect to the recording power as in FIG. From this, it can be seen that the 3T phase shift enables the recording power control in the control substantially equivalent to β.

  FIG. 6 shows an optical disk in which three drives are 30 degrees and β and 3T phase shifts appear to be “0”. When the temperature of the optical disk apparatus is changed between 0 degrees and 50 degrees, β and 3T of the optical disk are changed. It summarizes how the appearance of the phase shift changes. Whereas β shows a peculiar change depending on the temperature for each drive, the 3T phase shift shows almost no change in characteristics due to temperature.

  Further, since the temperature characteristic of β becomes an error that cannot be ignored compared with the actual value of the power margin of the optical disk apparatus, the power control by β is inaccurate, and the power control by β is not performed, and the 3T phase shift is not performed. That is why power control is excellent.

  Regardless of the temperature change of the optical disk device, it can contribute to the improvement of the recording quality, and the improvement of the recording quality can be realized.

Configuration diagram of an optical disc apparatus for executing the recording power control method of the present invention Main part flowchart of the same embodiment Correction table explanatory drawing of the same embodiment Detailed flowchart of the embodiment Comparison diagram of β and 3T phase shift Explanatory diagram of experimental results on how β and 3T phase shifts appear when the temperature of three optical disk devices is changed between 0 ° and 50 °

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 2 Spindle motor 3 Spindle motor control circuit 4 Optical pick-up 5 Servo processor 7 Phase error measuring device 8 Recording power controller 9 Laser drive circuit

Claims (6)

When controlling the recording power recorded on the optical disc by the optical pickup,
Measure the phase error amount of the recording signal,
A recording power control method in an optical disc apparatus for controlling the recording power based on a phase error amount obtained by measurement. When controlling the recording power recorded on the optical disc by the optical pickup,
Measure the phase error amount of the recording signal,
A recording power control method in an optical disc apparatus that controls the recording power based on a result of comparing a preset target phase error amount and a phase error amount obtained by the measurement. When controlling the recording power recorded on the optical disc by the optical pickup,
Recording a signal on the optical disc using a predetermined recording power, measuring the phase error amount of the recorded signal,
A recording power control method in an optical disc apparatus that controls the recording power based on a result of comparing a preset target phase error amount and a phase error amount obtained by the measurement. When controlling the recording power recorded on the optical disc by the optical pickup,
Recording a signal on the optical disc using a predetermined recording power, measuring the phase error amount of the recorded signal,
Based on the result of comparing the target phase error amount set in advance and the phase error amount obtained by the measurement, the power correction amount for the difference between the target phase error amount and the measured phase error amount is set,
A recording power control method in an optical disc apparatus for recording with a recording power corrected by the power correction amount. Measurement of the phase error of the recorded signal
5. The recording power control method for an optical disc apparatus according to claim 1, wherein the phase of the designated code mark of the EFM signal after the designated code space of the EFM signal is measured. An optical disc apparatus configured to execute the recording power control method according to any one of claims 1 to 5.

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