JP2002279674A - Optical disk recording and reproducing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk recording and reproducing device and a method for controlling the device with which recording mark of a high quality is formed independent of the performance of a focusing control, thus the variance of the amplitude of a reproduced signal is suppressed, an optimum recording condition for write-in of data is set. SOLUTION: The value Pw of a recording power, with which asymmetry of various reproducing signals which have different distances of polarity inversion which are read out of an optical disk 11 is optimized, is set as a recording condition. The device and the method are characterized by the fact that the pulse width of a recording pulse for recording data on the optical disk 11 is variable from a reference pulse width on the basis of a comparison of the recording power Pw and the value Pr of a preliminarily assumed recording power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc recording / reproducing apparatus for recording / reproducing data on / from a writable optical disc and a control method therefor.

[0002]

2. Description of the Related Art As is well known, recently, for example, CD-
Data writable optical disks, such as R and DVD-R, have been developed and put into practical use.

[0003] In this writable optical disk, the optical disk itself has variations in recording and reproduction performance. Also, the optical disc recording / reproducing apparatus for recording / reproducing data on / from this optical disc also has variations in performance of components and elements to be used, and a mechanical section and a circuit section formed by using them.

For this reason, in an optical disk recording / reproducing apparatus, if the setting of each section necessary for data recording is fixed, data recording under optimum recording conditions cannot be performed depending on the optical disk used. Inconvenience occurs.

Therefore, conventionally, a trial writing area for trial writing data on an optical disk is provided, and an optical disk recording / reproducing apparatus writes data once in the trial writing area prior to writing data on the optical disk. In order to control the setting of each part necessary for data recording to an optimum state by checking the reproduced data.

For the control of this optimization, for example, OPC (Op
timum Power Calibration) method. Hereinafter, the OPC method will be briefly described.

For example, in an optical disk such as a CD-R,
The data recorded on the optical disk has a minimum polarity inversion interval of 3T, where T is the cycle of the bit synchronization clock of the data.
And the maximum polarity inversion interval is set to 11T.

For this reason, first, the recording power level is changed stepwise by a recording pulse having a standard pulse width in the test writing area of the optical disk, and data having the polarity reversal intervals of 3T and 11T are written in the test writing area. Record in different locations. For example, if the polarity reversal interval of the test writing data is 3
T, 3T, and 11T, FIGS. 4A and 4D
As shown in FIGS. 4B and 4E, a recording laser beam RB is used to irradiate a recording mark M by using a recording pulse having a standard pulse width of 3T and 11T as shown in FIG.
Is recorded, and data is recorded such that the polarity reversal intervals are 3T and 11T.

Then, the data of the polarity reversal intervals 3T and 11T recorded in the test writing area of the optical disk while changing the recording power level stepwise are irradiated with the reproduction laser beam PB and read. A reproduction signal is obtained. Then, the central level is detected from the amplitude of the obtained reproduction signal, and the level of the detected reproduction signal is determined as the recording power.

In FIG. 4C and FIG. 4F, a plurality of reproduction signals for different recording powers are normally obtained. However, here, for simplicity, a polarity reversal interval of 3T is set in a test writing area at a certain recording power value P1. And 11T data are shown as test data, which are read by irradiating the laser beam PB with the laser beam PB. That is, when the reproduction signal is trial-written at the recording power value P1, it is determined from the median level of the amplitude of the reproduction signal that the optimum recording power is P1.

Therefore, the center level detected as described above, that is, the recording power at which the asymmetry (asymmetry) becomes substantially "0" is searched, and the searched recording power is recorded in the original data. Set as the recording conditions for the time.

[0012]

By the way, a recording laser beam RB for recording data on an optical disk is:
The laser light emitted from the semiconductor laser is guided to an objective lens via a predetermined optical path, and the objective lens is controlled in the focus direction to be focused on the signal recording surface of the optical disk, thereby being generated. I have.

[0013] However, the focus control means for the objective lens also has a variation in its performance, so that the focus is defocused, that is, the size of the light spot formed on the optical disk by the recording laser beam RB varies. As a result, the quality of the recording marks M formed on the optical disc varies, resulting in a problem that data cannot be written under optimum recording conditions.

For example, when the light spot is blurred, the intensity at the center of the spot is reduced. Therefore, in order to obtain a predetermined asymmetry, a stronger power is required as compared with the normal spot. The recording quality is not improved because the spot is very long (also long in the radial direction). In this case, the recording quality is improved by shortening the recording pulse in order to compensate for the lengthening of the light beam in the track direction.

The present invention has been made in consideration of the above circumstances, and enables formation of high-quality recording marks regardless of the performance of focus control. As a result, variations in the quality of recording marks M can be suppressed. It is an object of the present invention to provide an optical disk recording / reproducing apparatus which can set an optimum recording condition for data writing, and a control method thereof.

[0016]

According to the present invention, there is provided an optical disk recording / reproducing apparatus for recording various data having different polarity reversal intervals on the basis of recording pulses set to a standard pulse width. It is intended to set as a recording condition a recording power at which the asymmetry of various reproduction signals having different polarity reversal intervals read from the optical disk and having different polarity inversions is optimally changed.

The pulse width of the recording pulse is set to a standard pulse width based on a comparison between the recording power at which the asymmetry of various reproduction signals having different polarity reversal intervals read from the optical disc is optimal and the recording power assumed in advance. A control means for controlling the width is provided.

Further, in the control method of the optical disk recording / reproducing apparatus according to the present invention, various kinds of data having different polarity reversal intervals can be stepwise changed in recording power based on a recording pulse set to a standard pulse width. The method is intended to control an optical disc recording / reproducing apparatus so that the recording power is set as a recording condition at which the asymmetry of various reproduction signals having different polarity reversal intervals read from the optical disc and written with different polarity inversion intervals is set as a recording condition. And

Then, based on a comparison between the recording power at which the asymmetry of various reproduction signals read from the optical disc having different polarity reversal intervals and the asymmetry is optimum and the recording power assumed in advance, the pulse width of the recording pulse is set to a standard pulse width. A control step for controlling the width is provided.

According to the configuration and method as described above, the pulse width of the recording pulse is changed from the standard pulse width by comparing the recording pulse with the recording power assumed in advance in the state where the recording power is set. Therefore, it is possible to form a high-quality recording mark regardless of the performance of the focus control. As a result, it is possible to suppress the variation in the amplitude of the reproduction signal and set the optimum recording condition for writing data.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a main part of an optical disk recording / reproducing apparatus described in this embodiment.

CPU for controlling the overall operation of the optical disk recording / reproducing apparatus for the optical disk 11
(Central Processing Unit) 12 writes and reads data. The memory 12, the laser control circuit 14, and the comparison circuit 19 are connected to the CPU 12. In the memory 13, various test writing data and a default value Pr of the recording power are recorded. The test writing data stored in the memory 13 is supplied to the laser control circuit 14 by the CPU 12. Also, memory 1
The default value of the recording power stored in
Is supplied to the comparison circuit 19. Laser control circuit 14
Generates various recording pulses having a standard pulse width based on the input test writing data.

The laser control circuit 14 has an optical head 15
Is connected. The optical head 15 includes a laser driver 15a, a laser diode 15b connected to the laser driver 15a, and a photodetector 15c that receives light reflected from the optical disk 11. Each recording pulse generated by the laser control circuit 14 is supplied to the laser driver 15a. The laser driver 15a controls the laser diode 15 based on the supplied recording pulses.
b is driven to emit light.

When reading data, the CPU 1
2 causes the laser control circuit 14 to generate a reproduction signal. When the laser driver 15a drives the laser diode 15b to emit light based on the reproduction signal, the optical disk 11 is irradiated with the reproduction laser beam PB. The photodetector 15c receives light reflected from the optical disk 11 by the reproducing laser beam PB. The photodetector 15c converts the reflected light into electrical RF (Radio Frequent
ncy) Convert to a signal. The photodetector 15c has R
The F amplifier circuit 16 is connected. Photo detector 1
The RF signal converted in 5c is supplied to the RF amplifier circuit 16 and amplified. The RF amplification circuit 16 includes a binarization circuit 17
And an asymmetry measuring circuit 18.

A reproduction signal output from the RF amplification circuit 16 is supplied to the binarization circuit 17 and the asymmetry measurement circuit 18, respectively. The binarization circuit 17 converts the supplied reproduction signal into binary digital reproduction data, and thereafter provides the reproduction of the content (image or sound).

The asymmetry measuring circuit 18 is connected to the CPU 12. The asymmetry measuring circuit 18 measures the asymmetry of the reproduced signal for each recording power from the inputted reproduced signal, and outputs the measurement result to the CPU 12.

The CPU 12 has an asymmetry measuring circuit 18.
From the measurement result, the recording power value Pw of the reproduced signal whose asymmetry is almost “0” is searched. CPU 12
Supplies the searched recording power value Pw to the comparison circuit 19 as a recording condition. The comparison circuit 19 compares the default recording power value Pr with the retrieved recording power value Pw, and supplies the result to the CPU 12.

FIG. 2 is a diagram showing a relationship between a recording pulse, recording data on an optical disk, and a reproduction signal.

The laser control circuit 14 generates various recording pulses having a standard pulse width as shown in FIG. 2A based on the test writing data recorded in the memory 13 supplied from the CPU 12. . The pulse width is
Indicates the width from rising to falling. These recording pulses can form respective recording marks M for recording data with a polarity inversion interval of 3T or 11T, for example, on the optical disk 11, as shown in FIG. 2B.

At the time of data reading, the CPU 12 generates a reproduction signal to the laser control circuit 14, and the laser driver 15a operates the laser diode 15 based on the reproduction signal.
By driving b to emit light, the reproduction laser beam PB is irradiated onto the optical disk 11 as shown in FIG. The photodetector 15c receives the reflected light from the optical disk 11 due to the reproducing laser beam PB, converts the reflected light into an electric RF (Radio Frequency) signal, and amplifies the RF signal by the RF amplifier circuit 16. A reproduced signal as shown in FIG. 2C is obtained.

The operation of the embodiment will be described below with reference to FIGS. FIG. 3 is a flowchart illustrating the operation of the embodiment.

That is, when the recording condition setting operation is started (step S1), the CPU 12 proceeds to step S2.
Various test write data are read from the memory 13, and in step 3, the recording power is gradually changed using a recording pulse having a standard pulse width based on the various test write data, and the polarity is changed. Reversal interval 3T and 11
The test data of T is written on the optical disk 11.

Thereafter, the CPU 12 proceeds to step S4.
The recorded data is reproduced, and in step S5, asymmetry measurement is executed for each recording power from the reproduced signal.

Then, the CPU 12 proceeds to step S6.
The optimum asymmetry, that is, the asymmetry which becomes almost “0” is searched from the measured asymmetry, and the recording power value Pw at this time is determined in step S7, and this recording power value Pw is supplied to the comparison circuit 19.

Thereafter, at step 8, the comparison circuit 19 compares the default recording power value Pr with the recording power value Pw, and supplies the result to the CPU 12. The CPU 12
In step S9, it is determined whether Pw> Pr or Pw <Pr based on the comparison result of the comparison circuit 19.

If it is determined that Pw> Pr (Yes), the CPU 12 determines in step 10 that the light spot formed on the optical disk by the recording laser beam RB is slightly widened, the resolution is degraded, and defocusing occurs. And notifies the laser control circuit 14 that the pulse width of the recording pulse for forming the recording mark M is narrower than the standard pulse width.

If it is determined in step 12 that Pw <Pr (Yes), in step 12, the CPU 1
2 determines that the light spot formed on the optical disk by the recording laser beam RB is sufficiently focused and in a focused state, and the pulse width of the recording pulse for forming the recording mark M is set to a standard value. The laser control circuit 14 is notified to make the pulse width wider than the pulse width.

In the case of step 15, it means that Pw = Pr, and the CPU 12 notifies the laser control circuit 14 to perform recording with the standard pulse width, and proceeds to the processing of step 14.

The laser control circuit 14 determines in step 13
A recording pulse having a pulse width based on the notification from the CPU 12 is generated and supplied to a laser driver 15 a included in the optical head 15. Then, in step 14, the laser diode 15b is driven to emit light by the supplied laser driver 15a, so that the recording laser beam RB is irradiated onto the optical disk 11, and data with a polarity reversal interval of 3T or 11T is recorded. Will be done.

As described above, in addition to the recording power value Pw,
By changing the pulse width of the recording pulse based on the comparison with the default value Pr of the recording power, it is possible to form a high-quality recording mark regardless of the focus control performance. As a result, the amplitude of the reproduction signal is reduced. Variations can be suppressed, and optimum recording conditions for data writing can be set.

The present invention is not limited to the above-described embodiment, but can be implemented with various modifications without departing from the scope of the invention.

[0043]

As described in detail above, according to the present invention,
It is possible to form high-quality recording marks regardless of the performance of focus control. As a result, it is possible to suppress variations in the amplitude of the reproduction signal and to set optimal recording conditions for data writing. An optical disk recording / reproducing apparatus and a control method thereof can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an optical disk recording / reproducing apparatus and a control method thereof according to the present invention.

FIG. 2 is a view for explaining a relationship between a recording pulse, recording data on an optical disc, and a reproduction signal according to the embodiment;

FIG. 3 is a flowchart shown to explain a series of operations in the embodiment collectively;

FIG. 4 is a view for explaining a method of setting an optimum recording power.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Optical disk 12 CPU 13 Memory 14 Laser control circuit 15 Optical head 16 RF amplifier circuit 17 Binarization circuit 18 Asymmetry measurement circuit 19 Comparison circuit

Claims (4)

[Claims] 1. A recording power for changing various recording powers with different polarity reversal intervals based on a recording pulse set to a standard pulse width with reference to a first recording power set in advance. Variable means; writing means for writing recording data to an optical disc based on the recording power changed by the recording power varying means; and recording for optimally asymmetry of various reproduction signals read from the optical disc and having different polarity inversion intervals. An optimal recording condition setting means for setting power as a recording condition; and a second recording power for setting asymmetry of various reproduction signals having different polarity reversal intervals read from the optical disc as optimal as recording conditions. Based on a comparison between the first recording power and the second recording power, the pulse width of the recording pulse is set to a standard value. An optical disk recording / reproducing apparatus comprising control means for controlling from a pulse width. 2. The control means, when the second recording power is higher than the first recording power, makes the pulse width of the recording pulse narrower than a standard pulse width, and
Is smaller than the first recording power,
2. The optical disk recording / reproducing apparatus according to claim 1, wherein a pulse width of the recording pulse is made wider than a standard pulse width. 3. Recording various data having different polarity reversal intervals based on a recording pulse set to a standard pulse width by changing the recording power with reference to a preset first recording power. An optical disk recording device for controlling an optical disk recording / reproducing apparatus so that data is written on an optical disk and a recording power at which asymmetry of various reproduction signals having different polarity reversal intervals read from the optical disk is optimized is set as a recording condition. In the control method of the reproducing apparatus, the first recording power and the second recording power are set in a state where the second recording power at which the asymmetry of various reproduction signals having different polarity reversal intervals read from the optical disc is optimized is set as the recording condition. Controlling the pulse width of the recording pulse from a standard pulse width based on a comparison with the recording power of the recording pulse. Control method for an optical disk recording and reproducing apparatus according to symptoms. 4. The control according to claim 1, wherein, when the second recording power is larger than the first recording power, the pulse width of the recording pulse is made smaller than a standard pulse width, and the second recording power becomes smaller than a standard pulse width. 4. The method according to claim 3, wherein when the first recording power is lower than the first recording power, the pulse width of the recording pulse is made wider than a standard pulse width.