JP3753418B2 - Optical disc recording / reproducing apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disk recording / reproducing apparatus for recording / reproducing data on / from a writable optical disk and a control method therefor.
[0002]
[Prior art]
As is well known, in recent years, optical discs capable of writing data, such as CD-R and DVD-R, have been developed and put into practical use.
[0003]
In this writable optical disc, there is a variation in performance related to recording / reproduction in the optical disc itself. The optical disc recording / reproducing apparatus for recording / reproducing data with respect to the optical disc also has variations in performance of components and elements to be used, and a mechanism unit and a circuit unit configured by using them.
[0004]
For this reason, in the optical disk recording / reproducing apparatus, if the setting of each part necessary for the data recording is fixed, the data recording under the optimum recording condition cannot be performed depending on the optical disk to be used. .
[0005]
Therefore, conventionally, a trial writing area for trial writing of data on an optical disk is provided, and the optical disk recording / reproducing apparatus once writes and reads data in the trial writing area prior to writing of data to the optical disk, By examining the reproduced data, the setting of each part necessary for data recording is controlled to an optimum state.
[0006]
This optimization control includes, for example, an OPC (Optimum Power Calibration) method. The OPC method will be briefly described below.
[0007]
For example, in an optical disc such as a CD-R, the data recorded on the optical disc is defined such that the minimum polarity inversion interval is 3T and the maximum polarity inversion interval is 11T, where T is the period of the data bit synchronization clock. .
[0008]
For this reason, first, the recording power level is changed stepwise with a recording pulse having a standard pulse width in the test writing area of this optical disc, and the data with the polarity inversion intervals of 3T and 11T is changed to different positions in the test writing area. To record. For example, when the polarity reversal intervals of the test writing data are 3T, 3T, and 11T, recording pulses having standard pulse widths of 3T and 11T as shown in FIGS. 4A and 4D are used. Then, as shown in FIGS. 4B and 4E, the recording laser beam RB is irradiated to form the recording mark M, and data with polarity inversion intervals of 3T and 11T is recorded.
[0009]
Thereafter, the data of the polarity reversal intervals 3T and 11T recorded in the trial writing area of the optical disc in a stepwise manner are read by irradiating the reproduction laser beam PB, and the reproduction signal is recorded for each recording power. can get. Then, the central level is detected from the amplitude of the obtained reproduction signal, and the level of the recording power of the detected reproduction signal is determined.
[0010]
In FIGS. 4C and 4F, a plurality of reproduction signals for each recording power can be originally obtained. However, in this case, it is simplified and the polarity inversion intervals 3T and 11T are set in the test writing area with a certain recording power value P1. The central level of the signal amplitude when the data is written by trial and read by irradiating the laser beam PB is shown. That is, when this reproduction signal is written by trial with the recording power value P1, it is determined that the optimum recording power is P1 from the center level of the amplitude of the reproduction signal.
[0011]
Therefore, the central level detected as described above, that is, the recording power at which the asymmetry (asymmetry) is almost “0” is searched, and the recorded recording power is recorded when the original data is recorded. Set as a condition.
[0012]
[Problems to be solved by the invention]
By the way, the recording laser beam RB for recording data on the optical disk guides the laser beam emitted from the semiconductor laser to the objective lens through a predetermined optical path, and controls the objective lens in the focus direction. The light is generated by focusing on the signal recording surface of the optical disc.
[0013]
However, the focus control means for the objective lens is also defocused due to variations in its performance, that is, the size of the light spot formed on the optical disk by the recording laser beam RB varies. The quality of the recording mark M formed thereon varies, and as a result, there is a problem that data cannot be written under optimum recording conditions.
[0014]
For example, when the light spot is blurred, the intensity at the center of the spot is reduced. Therefore, to obtain a predetermined asymmetry, a stronger power is required as compared with the normal spot, but the blurred spot is longer in the track direction than the normal spot ( The recording quality is not improved because the spot is long in the radial direction. In this case, since the length of the light beam is increased in the track direction, the recording quality is improved by shortening the recording pulse.
[0015]
Therefore, the present invention has been made in consideration of the above circumstances, and enables formation of a high-quality recording mark regardless of the focus control performance. As a result, it is possible to suppress variations in the quality of the recording mark M and to write data. Therefore, an object of the present invention is to provide an extremely good optical disc recording / reproducing apparatus and a control method thereof that make it possible to set optimum recording conditions.
[0016]
[Means for Solving the Problems]
The optical disc recording / reproducing apparatus according to the present invention writes various data with different polarity inversion intervals to the optical disc by changing the recording power stepwise based on the recording pulse set to the standard pulse width, It is intended for recording conditions in which the recording power at which the asymmetry of various reproduction signals read from an optical disc with different polarity inversion intervals is optimum is set as a recording condition.
[0017]
The pulse width of the recording pulse is controlled from the standard pulse width based on a comparison between the recording power at which the asymmetry of various reproduction signals read from the optical disc with different polarity inversion intervals is optimal and the recording power assumed in advance. The control means to perform is provided.
[0018]
Also, the control method of the optical disc recording / reproducing apparatus according to the present invention changes the recording power step by step for various data with different polarity inversion intervals based on the recording pulse set to the standard pulse width. The present invention is directed to a method for controlling an optical disc recording / reproducing apparatus so as to set, as a recording condition, a recording power at which asymmetry of various reproduction signals having different polarity reversal intervals written to and read from the optical disc is optimum.
[0019]
The pulse width of the recording pulse is controlled from the standard pulse width based on a comparison between the recording power at which the asymmetry of various reproduction signals read from the optical disc with different polarity inversion intervals is optimal and the recording power assumed in advance. And a control step for performing the above.
[0020]
According to the configuration and method as described above, the recording pulse width is changed from the standard pulse width by comparison with the recording power assumed in advance in a state where the recording power is set. Regardless of the control performance, it is possible to form a high-quality recording mark. As a result, it is possible to suppress variation in the amplitude of the reproduction signal and set an optimum recording condition for data writing.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0022]
FIG. 1 is a block diagram showing the structure of the main part of the optical disk recording / reproducing apparatus described in this embodiment.
[0023]
Data is written to and read from the optical disc 11 by a CPU (Central Processing Unit) 12 that controls the overall operation of the optical disc recording / reproducing apparatus. A memory 13, a laser control circuit 14, and a comparison circuit 19 are connected to the CPU 12. Various test writing data and a default value Pr of recording power are recorded in the memory 13. The test writing data stored in the memory 13 is supplied to the laser control circuit 14 by the CPU 12. The default value of the recording power stored in the memory 13 is supplied to the comparison circuit 19 by the CPU 12. The laser control circuit 14 generates various recording pulses having a standard pulse width based on the inputted test writing data.
[0024]
An optical head 15 is connected to the laser control circuit 14. 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 reflected light 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 drives the laser diode 15b to emit light based on each supplied recording pulse.
[0025]
At the time of reading data, the CPU 12 causes the laser control circuit 14 to generate a reproduction signal. Based on the reproduction signal, the laser driver 15a drives the laser diode 15b to emit light, whereby the reproduction laser beam PB is irradiated onto the optical disk 11. The photodetector 15c receives the reflected light from the optical disk 11 by the reproducing laser beam PB. The photodetector 15c converts the reflected light into an electrical RF (Radio Frequency) signal. An RF amplifier circuit 16 is connected to the photodetector 15c. The RF signal converted by the photodetector 15c is supplied to the RF amplifier circuit 16 and amplified. A binarization circuit 17 and an asymmetry measurement circuit 18 are connected to the RF amplifier circuit 16.
[0026]
The binarization circuit 17 and the asymmetry measurement circuit 18 are respectively supplied with reproduction signals output from the RF amplifier circuit 16. The binarization circuit 17 converts the supplied reproduction signal into binary digital reproduction data, which is then used for reproducing contents (images and sounds).
[0027]
The asymmetry measurement circuit 18 is connected to the CPU 12. The asymmetry measurement circuit 18 measures the asymmetry of the reproduction signal for each recording power from the input reproduction signal, and outputs the measurement result to the CPU 12.
[0028]
The CPU 12 searches the recording power value Pw of the reproduction signal whose asymmetry is substantially “0” from the measurement result of the asymmetry measurement circuit 18. The CPU 12 supplies the retrieved recording power value Pw to the comparison circuit 19 as a recording condition. The comparison circuit 19 compares the recording power default value Pr with the retrieved recording power value Pw and supplies the result to the CPU 12.
[0029]
FIG. 2 is a diagram showing the relationship between the recording pulse, the recording data on the optical disc, and the reproduction signal.
[0030]
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 indicates the width from rising to falling. These recording pulses can form recording marks M for recording data having a polarity reversal interval of 3T or 11T, for example, as shown in FIG.
[0031]
At the time of data reading, the CPU 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, thereby reproducing as shown in FIG. A laser beam PB is irradiated onto the optical disk 11. The photodetector 15c receives the reflected light from the optical disk 11 by the reproducing laser beam PB, converts the reflected light into an electrical RF (Radio Frequency) signal, and the RF amplification circuit 16 amplifies the RF signal, A reproduction signal as shown in FIG. 2C is obtained.
[0032]
The operation of the embodiment will be described below with reference to FIGS. FIG. 3 is a flowchart for explaining the operation of the embodiment.
[0033]
That is, when the recording condition setting operation is started (step S1), the CPU 12 reads various test writing data from the memory 13 in step S2, and in step 3, the standard based on the various test writing data. Using the recording pulse having the pulse width of, the data at the polarity inversion intervals 3T and 11T are written on the optical disc 11 while changing the recording power stepwise.
[0034]
Thereafter, the CPU 12 reproduces the recorded data in step S4, and executes asymmetry measurement for each recording power from the reproduction signal in step S5.
[0035]
Then, in step S6, the CPU 12 searches for the optimum asymmetry from the measured asymmetry, that is, the asymmetry that is substantially “0”, determines the recording power value Pw at this time in step S7, and sends it to the comparison circuit 19. A recording power value Pw is supplied.
[0036]
Thereafter, in step 8, the comparison circuit 19 compares the recording power default value Pr with the recording power value Pw, and supplies the result to the CPU 12. In step S9, the CPU 12 determines whether Pw> Pr or Pw <Pr based on the comparison result in the comparison circuit 19.
[0037]
If it is determined that Pw> Pr (Yes), in step 10, the CPU 12 determines that the light spot formed on the optical disc by the recording laser beam RB is spread and is out of focus because the resolution is degraded. Determination is made and the laser control circuit 14 is notified so that the pulse width of the recording pulse for forming the recording mark M is narrower than the standard pulse width.
[0038]
If it is determined in step 12 that Pw <Pr (Yes), the CPU 12 in step 12 causes the light spot formed on the optical disk by the recording laser beam RB to be sufficiently focused and in a focused state. The laser control circuit 14 is notified that the pulse width of the recording pulse for forming the recording mark M is wider than the standard pulse width.
[0039]
In the case of step 15, this means that Pw = Pr, and the CPU 12 notifies the laser control circuit 14 to record with the standard pulse width, and the process proceeds to step 14.
[0040]
In step 13, the laser control circuit 14 generates a recording pulse having a pulse width based on the notification from the CPU 12, and supplies this to a laser driver 15 a that constitutes the optical head 15. Then, the laser diode 15b is driven to emit light in step 14 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 inversion interval of 3T or 11T is recorded. Will come to be.
[0041]
Thus, by changing not only the recording power value Pw but also the recording pulse width based on the comparison with the recording power default value Pr, high-quality recording marks can be formed regardless of the focus control performance. As a result, it is possible to suppress variation in the amplitude of the reproduction signal and set an optimum recording condition for data writing.
[0042]
The present invention is not limited to the above-described embodiment, and can be variously modified and implemented without departing from the scope of the invention.
[0043]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to form a high-quality recording mark regardless of the focus control performance, and as a result, it is possible to suppress the variation in the amplitude of the reproduction signal and to perform optimum recording for data writing. It is possible to provide a very good optical disk recording / reproducing apparatus and its control method that make it possible to set conditions.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram for explaining an embodiment of an optical disc recording / reproducing apparatus and its control method according to the present invention.
FIG. 2 is a view for explaining a relationship among a recording pulse, recording data on an optical disc, and a reproduction signal in the embodiment;
FIG. 3 is a flowchart shown for collectively explaining a series of operations in the embodiment;
FIG. 4 is a view for explaining a method of setting an optimum recording power.
[Explanation of symbols]
11 Optical disk 12 CPU
13 Memory 14 Laser Control Circuit 15 Optical Head 16 RF Amplifier 17 Binary Circuit 18 Asymmetry Measurement Circuit 19 Comparison Circuit

Claims (4)

A recording power variable means for changing various recording powers of various data having different polarity inversion intervals based on a first recording power set in advance based on a recording pulse set to a standard pulse width;
Writing means for writing recording data to the optical disk based on the recording power changed by the recording power variable means;
Optimum recording condition setting means for setting a recording power at which asymmetry of various reproduction signals having different polarity reversal intervals read from the optical disc is optimum as a recording condition;
For comparison between the first recording power and the second recording power in a state where the second recording power is set as the recording condition in which the asymmetry of various reproduction signals having different polarity inversion intervals read from the optical disk is optimum. An optical disc recording / reproducing apparatus comprising control means for controlling the pulse width of the recording pulse from a standard pulse width. When the second recording power is larger than the first recording power, the control means makes the pulse width of the recording pulse narrower than a standard pulse width, and the second recording power is the first recording power. 2. The optical disc recording / reproducing apparatus according to claim 1, wherein when the power is smaller than the standard pulse width, the recording pulse is wider than the standard pulse width. Based on the recording pulse set to the standard pulse width, various data with different polarity reversal intervals are written on the optical disc by changing the recording power based on the preset first recording power. Control method of optical disk recording / reproducing apparatus for controlling optical disk recording / reproducing apparatus so as to set recording power at which asymmetry of various reproduction signals having different polarity reversal intervals read from optical disk is optimal In
For comparison between the first recording power and the second recording power in a state where the second recording power is set as the recording condition in which the asymmetry of various reproduction signals having different polarity inversion intervals read from the optical disk is optimum. And a control method for an optical disc recording / reproducing apparatus, wherein the pulse width of the recording pulse is controlled from a standard pulse width. When the second recording power is larger than the first recording power, the control makes the pulse width of the recording pulse narrower than a standard pulse width, and the second recording power is the first recording power. 4. The method of controlling an optical disc recording / reproducing apparatus according to claim 3, wherein when the width is smaller, the pulse width of the recording pulse is wider than a standard pulse width.

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