JP2002237045A - Optical disk recording and playback unit and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk recording and playback unit which can form a high-definition record mark irrespective of performance of focus control and which accordingly, suppresses variations in the amplitudes of reproduction signals and can set record conditions most suitable for data writing, and to provide its control method. SOLUTION: Record power which optimizes the asymmetry of various kinds of reproduction signals read from an optical disk 11 and having different inversion intervals, is set as a record condition. The pulse width of a record pulse for recording data on the optical disk 11 is varied from a standard pulse width on the basis of the difference of the amplitude level of each reproduction signal having a different inversion interval in which the asymmetry is optimized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical disk recording / reproducing apparatus for recording / reproducing data on / from a rewritable optical disk and a control method thereof.

[0002]

2. Description of the Related Art As is well known, recently, for example, DVD
(Digital Versatile Disc)-R (Recordable) and CD
Data rewritable optical disks, such as (Compact Disc) -R, have been developed and put into practical use.

By the way, such a rewritable optical disk has its own performance variation in recording and reproduction. Also, an optical disc recording / reproducing apparatus for recording / reproducing data on / from this optical disc also has variations in the performance of components and elements used, and a mechanical unit and a circuit unit configured 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.

Although this control actually requires extremely complicated processing, for example, OPC (Optimum Power Calibration)
The method will be briefly described for convenience as follows.

For example, in an optical disk such as a DVD-R, data recorded on the optical disk is defined such that the minimum polarity inversion interval is 3T and the maximum polarity inversion interval is 11T, where T is the cycle of the bit synchronization clock. ing.

For this reason, first, a recording laser having a standard pulse width as shown in FIG. 4A is used in a test writing area of this optical disc, as shown in FIG. By irradiating the beam RB to form the phase change mark M, data is recorded such that the polarity inversion interval becomes 3T.

In this case, data having a polarity inversion interval of 3T is recorded at different positions in the test writing area by using recording pulses having the same standard pulse width and changing the level stepwise. That is, the recording power is changed stepwise, and the data at the polarity reversal interval 3T is recorded at different positions in the test writing area.

After that, data of the polarity reversal interval 3T recorded in the test writing area of the optical disk while changing the recording power stepwise is read by irradiating the reproduction laser beam PB with the recording power, and FIG. As shown in c),
The center level CL1 of the amplitude of the reproduced signal is detected.

[0011] Next, FIG.
By using a recording pulse having a standard pulse width as shown in FIG. 4D and irradiating a recording laser beam RB to form a phase change mark M as shown in FIG. Data is recorded such that the interval is 11T.

Also in this case, data having a polarity inversion interval of 11T is recorded at different positions in the test writing area by using recording pulses having the same standard pulse width and changing the level stepwise. That is, the recording power is changed stepwise, and the data at the polarity reversal interval 11T is recorded at different positions in the test writing area.

Thereafter, data of the polarity reversal interval 11T recorded in the test writing area of the optical disc while changing the recording power in a stepwise manner is read by irradiating the reproduction laser beam PB with the recording power, and FIG. As shown in f), the center level CL2 of the amplitude of the reproduced signal is detected.

The center level CL1 of the amplitude of each reproduction signal corresponding to the data of the polarity inversion interval 3T and the center of the amplitude of each reproduction signal corresponding to the data of the polarity inversion interval 11T detected as described above. From the level CL2, a search is made for a recording power at which both the levels CL1 and CL2 are equal, that is, the asymmetry (asymmetry) is almost “0”.
The searched recording power is set as a recording condition for recording the original data.

[0015]

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.

However, the focus control means for the objective lens is also out of focus because of its performance variations, 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 phase change mark M formed on the optical disc varies, and as a result, the amplitude of the reproduced signal varies, so that there is a problem that data cannot be written under the optimum recording condition.

Therefore, the present invention has been made in view of the above circumstances, and enables formation of a high-quality recording mark regardless of the focus control performance. It is an object of the present invention to provide an extremely good optical disk recording / reproducing apparatus which enables setting of optimum recording conditions for writing and a control method thereof.

[0018]

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.

Then, in a state where the recording power at which the asymmetry of various reproduction signals having different polarity reversal intervals read from the optical disk is optimum is set as a recording condition, the reproduction signals having different polarity reversal intervals at which the asymmetry is optimum are set. And a control means for controlling the pulse width of the recording pulse from a standard pulse width based on the difference between the amplitude levels of the recording pulses.

Further, in the control method of the optical disk recording / reproducing apparatus according to the present invention, the recording power of each of various data having different polarity inversion intervals is gradually increased 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, in a state in which the recording power at which the asymmetry of various reproduction signals read from the optical disc with different polarity reversal intervals is optimal is set as the recording condition, the reproduction signals with different polarity reversal intervals at which the asymmetry is optimal are set. And a control step of controlling the pulse width of the recording pulse from a standard pulse width based on the difference between the amplitude levels of the recording pulses.

According to the above configuration and method, the recording pulse width is set to the standard pulse width based on the difference between the amplitude levels of the reproduction signals having different polarity inversion intervals while the recording power is set. Since it was changed from
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.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a main part of an optical disc recording / reproducing apparatus described in this embodiment. That is, in FIG.
Reference numeral 1 denotes an optical disk capable of rewriting data.

Then, a CPU (Central Processing Unit) 12 for controlling the entire operation of the optical disk recording / reproducing apparatus with respect to the optical disk 11 is provided.
Data writing and reading are performed. less than,
2 (a), 2 (b) and 2 (c), the optical disc 1
Writing and reading of data in one test writing area will be described.

First, when writing data, the CP
The U12 reads various test writing data recorded in the memory 13 and supplies the data to the laser control circuit 14. The laser control circuit 14 generates various recording pulses having a standard pulse width as shown in FIG. 2A based on the input test writing data.

As these recording pulses, for example, each phase change mark M for recording data with a polarity inversion interval of 3T or 11T as shown in FIG. 2B can be formed on the optical disk 11, for example. Things.

Each recording pulse generated by the laser control circuit 14 is supplied to a laser driver 15a constituting an optical head 15, and the laser driver 15a
When the laser diode 15b is driven to emit light by a, the recording laser beam RB is irradiated onto the optical disk 11 as shown in FIG. 2B, and data with a polarity inversion interval of 3T or 11T is recorded. Become like

In this case, under the control of the CPU 12, the level of each recording pulse is changed in a stepwise manner, and data having a polarity inversion interval of 3T or 11T is transferred to the optical disk 1.
Each is recorded at one different position. That is, the data at the polarity inversion intervals 3T and 11T are recorded at different positions on the optical disc 11 by changing the recording power stepwise.

On the other hand, when reading data, C
The PU 12 generates a reproduction signal in the laser control circuit 14, and the laser driver 15a drives the laser diode 15b to emit light based on the reproduction signal.
As shown in FIG. 2B, the reproduction laser beam PB is irradiated onto the optical disc 11.

The light reflected from the optical disk 11 by the reproducing laser beam PB is applied to the photodetector 1.
The light is received by 5c, converted into an electric RF (Radio Frequency) signal, supplied to the RF amplifier circuit 16 and amplified, whereby a reproduced signal as shown in FIG. 2C is obtained.

Here, the reproduced signal output from the RF amplification circuit 16 is supplied to a binarization circuit 17, an asymmetry measurement circuit 18 and an amplitude measurement circuit 19, respectively. Among them, the reproduction signal supplied to the binarization circuit 17 is converted into binary digital reproduction data, and thereafter, is used for reproducing contents (images and sounds).

The asymmetry measuring circuit 18
From the input reproduction signal, for each recording power, a reproduction signal corresponding to the data of the polarity reversal interval 3T and the polarity reversal interval 1
The asymmetry with the reproduction signal corresponding to the 1T data is measured, and the measurement result is output to the CPU 12.

Further, the amplitude measuring circuit 19 calculates the amplitude level P3 of the reproduction signal corresponding to the data of the polarity inversion interval 3T and the amplitude level of the reproduction signal corresponding to the data of the polarity inversion interval 11T from the input reproduction signal. P11 is measured, and the measurement result is output to the CPU 12.

Here, the CPU 12 retrieves the recording power of the reproduced signal whose asymmetry is almost "0" from the measurement result of the asymmetry measuring circuit 18, and sets the retrieved recording power as the recording condition. .

Thereafter, the CPU 12 determines from the measurement result of the amplitude measuring circuit 19 that the ratio P11 / P of the amplitudes P3 and P11 of the reproduced signals whose asymmetry is substantially "0".
3, and controls the laser control circuit 14 so that the pulse width of each recording pulse for forming the phase change mark M of 3T or 11T is changed from the standard pulse width according to the value of this ratio. I do.

That is, the fact that P11 / P3 is large means that the amplitude level P11 of the reproduction signal corresponding to the data of the polarity inversion interval 11T and the amplitude level P3 of the reproduction signal corresponding to the data of the polarity inversion interval 3T are large. There is a difference, which means that the light spot formed on the optical disk by the recording laser beam RB tends to spread and the resolution is deteriorated, that is, the focus is out of focus. Means that.

Conversely, the fact that P11 / P3 is smaller means that the amplitude level P11 of the reproduced signal corresponding to the data of the polarity inversion interval 11T and the amplitude level P3 of the reproduced signal corresponding to the data of the polarity inversion interval 3T are different. The difference is small, which means that the light spot formed on the optical disk by the recording laser beam RB is sufficiently focused to be in a focused state without being corrected.

Therefore, P11 / P3 is compared with a predetermined threshold value (for example, 1.4) to determine P11 / P3.
Is substantially larger than the threshold value, the pulse width of the recording pulse for forming the phase change mark M is made narrower than a preset standard pulse width.

On the contrary, when P11 / P3 is substantially smaller than the threshold value, the pulse width of the recording pulse for forming the phase change mark M is made wider than the preset standard pulse width. I do.

After setting not only the recording power but also the recording power, the amplitude level P11 of the reproduction signal corresponding to the data of the polarity inversion interval 11T and the reproduction signal of the reproduction signal corresponding to the data of the polarity inversion interval 3T are set. By changing the pulse width of the recording pulse based on the ratio to the amplitude level P3, it is possible to form a high-quality recording mark regardless of the focus control performance. As a result, the variation in the amplitude of the reproduction signal is suppressed. This makes it possible to set optimum recording conditions for writing data.

FIG. 3 is a flowchart summarizing a series of operations as described above. That is, when started (step S1), the CPU 12 proceeds to step S2.
The value N of a built-in counter (not shown) is set to “0”, and in step S3, the recording power is gradually changed using a recording pulse having a standard pulse width, and the polarity inversion intervals 3T and 11T are changed. Are written on the optical disk 11 in a trial manner.

Thereafter, the CPU 12 proceeds to step S4.
The value N of the counter is set to "+1", and the recorded data is reproduced in step S5, and in step S6, the asymmetry is measured for each recording power from the reproduced signal.

Then, the CPU 12 proceeds to step S7.
From the measured asymmetry, an optimum asymmetry, that is, an asymmetry that becomes substantially "0" is searched, and in step S8, the amplitude levels P3 and P11 of the reproduced signal having the optimum asymmetry are input.

Thereafter, the CPU 12 proceeds to step S9.
The ratio P11 / P3 of the amplitude levels P3 and P11 is calculated, and in step S10, the ratio P11 / P3 is 1.4 ± 0.1.
It is determined whether it is within the range.

Then, the ratio P11 / P3 is 1.4 ± 0.1.
Is determined to be within the range (YES), C
In step S11, the PU 12 sets the recording power at which the reproduced signal has been previously optimally asymmetry set as the optimal recording condition. In step S12, the PU 12 executes the original data writing process and ends (step S13).

In step S10, the ratio P11 / P
3 is not within the range of 1.4 ± 0.1 (NO), the CPU 12 determines in step S14 whether the ratio P11 / P3 is P11 / P3 <1.3. Determine.

If it is determined that P11 / P3 <1.3 (YES), the CPU 12 proceeds to step S1.
5, the recording pulse width is set to “standard pulse width +
(0.05 × N) T ”, and while the recording power is changed stepwise, data of the polarity reversal intervals 3T and 11T are respectively trial written on the optical disk 11, and the process returns to step S4. .

In step S14, P11 / P3
If it is determined that it is not <1.3 (NO), the CPU 12
In step S16, the pulse width of the recording pulse is narrowed to “standard pulse width− (0.05 × N) T”, and the polarity reversal interval is set to 3T while gradually changing the recording power again.
And 11T data are written on the optical disk 11 as a test, and the process returns to the step S4.

The present invention is not limited to the above-described embodiment, but can be variously modified and implemented without departing from the spirit and scope of the invention.

[0050]

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.

[Description of Signs] 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 ... Amplitude measurement circuit.

Claims (6)

[Claims] 1. A method of writing various data having different polarity reversal intervals on an optical disc by changing recording power in a stepwise manner based on a recording pulse set to a standard pulse width, and reading the polarity reversal read from the optical disc. In an optical disc recording / reproducing apparatus for setting a recording power at which the asymmetry of various reproduction signals having different intervals is optimal as a recording condition, the asymmetry of various reproduction signals having different polarity reversal intervals read from the optical disc is optimized. With the power set as the recording condition, control for controlling the pulse width of the recording pulse from a standard pulse width based on the difference between the amplitude levels of the reproduced signals having different polarity inversion intervals at which the asymmetry is optimized. An optical disc recording / reproducing apparatus characterized by comprising means. 2. The control unit according to claim 1, wherein the difference between the amplitude levels of the various reproduction signals having different polarity reversal intervals read from the optical disk becomes substantially larger than a preset threshold value. As the pulse width of the recording pulse is made narrower than the standard pulse width, as the difference between the amplitude levels of various reproduction signals read from the optical disc having different polarity inversion intervals becomes substantially smaller than the threshold value, 2. The optical disk recording / reproducing apparatus according to claim 1, wherein a pulse width of said recording pulse is made wider than a standard pulse width. 3. The control unit according to claim 1, wherein the difference between the amplitude levels of various reproduction signals having different polarity reversal intervals read from the optical disk is within a predetermined range set in advance. The width remains the standard pulse width, and as the difference between the amplitude levels of various reproduction signals having different polarity reversal intervals read from the optical disk becomes substantially larger than the predetermined range, the recording pulse The pulse width is made narrower than a standard pulse width, and as the difference between the amplitude levels of various reproduction signals having different polarity reversal intervals read from the optical disk becomes substantially smaller than the predetermined range, the recording is performed. 2. The optical disk recording / reproducing apparatus according to claim 1, wherein the pulse width of the pulse is made wider than a standard pulse width. 4. Based on a recording pulse set to a standard pulse width, various types of data having different polarity reversal intervals are written to an optical disc by changing the recording power in a stepwise manner, and the polarity reversal read from the optical disc is performed. In a control method of an optical disk recording / reproducing apparatus for controlling an optical disk recording / reproducing apparatus, such that a recording power at which asymmetry of various reproduction signals having different intervals is optimal is set as a recording condition, the polarity read from the optical disk is In a state where the recording power at which the asymmetry of various reproduction signals having different inversion intervals is optimal is set as a recording condition, based on the difference between the amplitude levels of the reproduction signals having different polarity inversion intervals at which the asymmetry is optimal, A control step of controlling a pulse width of the recording pulse from a standard pulse width. Control method for an optical disk recording and reproducing apparatus according to. 5. The method according to claim 1, wherein the difference between the amplitude levels of various reproduction signals having different polarity reversal intervals read from the optical disk becomes substantially larger than a preset threshold value. As the pulse width of the recording pulse is made narrower than the standard pulse width, as the difference between the amplitude levels of various reproduction signals read from the optical disc having different polarity inversion intervals becomes substantially smaller than the threshold value, 5. The method according to claim 4, wherein a pulse width of the recording pulse is made wider than a standard pulse width. 6. The method according to claim 6, wherein the control step includes: when a difference between amplitude levels of various reproduction signals having different polarity reversal intervals read from the optical disk is within a predetermined range, a pulse of the recording pulse is controlled. The width remains the standard pulse width, and as the difference between the amplitude levels of various reproduction signals having different polarity reversal intervals read from the optical disk becomes substantially larger than the predetermined range, the recording pulse The pulse width is made narrower than a standard pulse width, and as the difference between the amplitude levels of various reproduction signals having different polarity reversal intervals read from the optical disc becomes substantially smaller than the predetermined range, the recording is performed. 5. The method according to claim 4, wherein the pulse width of the pulse is wider than a standard pulse width.