JP2005038543A - Method for setting laser output of optical disk recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for setting laser output of an optical disk recording and reproducing device for carrying out recording and reproducing operation of a signal to a disk by an optical pickup. <P>SOLUTION: A test signal is recorded in a trial writing area provided on the disk while changing laser output and the recording grade of the recorded test signal is detected to set the laser output suitable for recording operation. In addition, a laser diode is driven with a multi-pulse consisting of an erasure level value, a peak level value and a bottom level value to carry out the recording operation. Setting operation of the laser output is carried out by changing the peak level value in the state of fixing the erasure level value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical disk recording / reproducing apparatus configured to record a signal on a disk with a laser beam irradiated from an optical pickup and perform a reproducing operation of the signal recorded on the disk with the laser beam.

  Optical disk playback devices that use an optical pickup to read signals recorded on a disk have become widespread. Recently, in addition to the playback function, a signal is output to the disk by laser light emitted from the optical pickup. Optical disc recording / reproducing apparatuses configured to be able to record are commercialized.

  As such an optical disk recording / reproducing apparatus, a method called “overwrite” which can be rewritten by overwriting the disk is generally used, and a CD-RW type recording / reproducing apparatus using a CD type recording disk is widely spread. Yes. In such an overwrite type optical disc recording / reproducing apparatus, a laser diode incorporated in an optical pickup is represented by a pulse signal called a multi-pulse composed of an erase level value E, a peak level value P and a bottom level value B shown in FIG. It is configured to drive the light and record the signal on the disk.

In an optical disk recording / reproducing apparatus that records a signal on a disk by driving a laser diode with a pulse signal having such a multi-pulse waveform, the erasing level value E, the peak level value P, and the bottom level value B are accurately controlled. A technique for performing a high-quality recording operation on a disc has been developed (see, for example, Patent Document 1).
JP 2001-34987 A

  In an optical disc recording / reproducing apparatus that records signals on a disc by driving a laser diode with a pulse signal having a multi-pulse waveform, a value BP from a bottom level value B to a peak level value P and a bottom level value B It is necessary to adjust the ε value, which is the ratio (BE / BP) to the value BE up to the erasure level E, and this ε value is unique to the disc and is determined according to the recording speed.

  In the case of a CD-RW device, the ε value is usually determined before adjusting the laser output of the disc, but this value is set by extracting data information representing the disc characteristics recorded on the disc.

  In addition, the optical disk recording / reproducing apparatus records a test signal in a test writing area provided on the inner circumference side of the disk while changing the laser output, and detects the recording quality of the recorded test signal. Configured to set the appropriate laser power. In this case, in order to perform the control operation of changing the laser output while controlling the erase level value E, the peak level value P, and the bottom level value so that the ε value described above matches the disk characteristics, There is a problem that the adjustment processing operation becomes complicated and the adjustment time becomes long.

  The present invention seeks to provide a laser output setting method that can solve such problems.

  The present invention records a test signal in a test writing area provided on the disc while changing the laser output and sets the laser output suitable for the recording operation by detecting the recording quality of the recorded test signal, In addition, in an optical disc recording / reproducing apparatus configured to perform a recording operation by driving a laser diode with a multi-pulse composed of an erasing level value, a peak level value, and a bottom level value, the setting operation of the laser output is performed by setting the erasing level value. It is configured to change the peak level value in a fixed state.

  According to the laser output setting method of the present invention, in an optical disc recording / reproducing apparatus that performs signal recording operation with multi-pulses composed of an erase level value, a peak level value, and a bottom level value, the erase level is adjusted when the laser output is adjusted. Since the test signal recording operation is performed by changing the peak level value in a fixed state, the laser output adjustment operation can be performed quickly.

  In the present invention, since the recording quality detection operation is performed based on the number of errors in the reproduction signal, that is, the error correction function provided in the optical disk recording / reproducing apparatus can be used. Without being provided, it can be incorporated into an optical disk recording / reproducing apparatus.

  In the present invention, since the recording quality detection operation is performed based on the β value, the recording quality can be accurately detected.

  In the present invention, the adjustment operation of the laser output is performed by a simple control operation of changing the peak level value constituting the multi-pulse which is a drive signal supplied to the laser diode.

  1 is a circuit diagram showing an embodiment of an optical disk recording / reproducing apparatus according to the present invention, FIG. 2 is a waveform diagram of a laser drive pulse signal used in the present invention, and FIG. 3 is a waveform for explaining the operation of the present invention. FIG.

  In FIG. 1, reference numeral 1 denotes a laser diode that is incorporated in an optical pickup and emits laser light, and is connected to be driven by a current supplied from a laser driving circuit 2. Reference numeral 3 denotes a photodetector that receives the laser light irradiated from the laser diode 1 and reflected from the disk, and has a function of converting the laser light into an electric signal.

  Reference numeral 4 denotes an RF signal amplifying circuit for inputting an RF signal (high frequency signal) converted into an electric signal by the photodetector 3 and amplifying the signal, and a binarizing circuit for outputting a binarized signal. Is incorporated. FIG. 2 shows a waveform of a laser driving pulse supplied to the laser diode 1, and a signal is recorded on the disc during a period in which a pulse signal changing between the peak level value P and the bottom level value is supplied. The recording period during which the signal of the erase level value E is supplied indicates the erase period. That is, a signal recording operation is performed on the disc during the recording period, and a signal erasing operation is performed during the erasing period.

Reference numeral 5 denotes a digital signal processing circuit that receives a digital signal output from the RF signal amplifier circuit 4 and demodulates various signals. The digital signal processing circuit 5 generates and outputs an error correction operation of the reproduced signal and a signal indicating the number of errors. Is configured to do. A control circuit 6 receives the signal demodulated by the digital signal processing circuit 5 and performs various control operations of the optical disc recording / reproducing apparatus.

  Reference numeral 7 denotes a peak level signal output circuit whose operation is controlled by the control circuit 6, and is set to output a signal for causing the laser drive circuit 2 to output a signal having a peak level value P for recording the signal on the disc. . Reference numeral 8 denotes a bottom level signal output circuit whose operation is controlled by the control circuit 6 and is set to output a signal for causing the laser drive circuit 2 to output a signal having a bottom level value B. Reference numeral 9 denotes an erasure level signal output circuit whose operation is controlled by the control circuit 6, and is set to output a signal for causing the laser drive circuit 2 to output an erasure level value E signal.

  Reference numeral 10 denotes an adder circuit to which the output signals of the peak level signal output circuit 7, the bottom level signal output circuit 8 and the erase level signal output circuit 9 are input. Selective addition of signals input by the control operation of the control circuit 6 An operation is performed, and the selectively added signal is supplied to the laser driving circuit 2.

  A recording quality detection circuit 11 detects the quality of a signal reproduced based on a signal representing the number of errors output from the digital signal processing circuit 5, that is, the recording quality of a signal recorded on a disk.

  In such a configuration, in a state where a signal is recorded in the signal recording area provided on the disk, the laser light emitted from the laser diode 1 is reflected from the disk and received by the photodetector 3, and output to the output. A corresponding RF signal is output. A multi-pulse is constructed by performing a sampling operation of the RF signal obtained in the erasing period and performing a servo operation on the erasing level signal output circuit 9 so that the level of the RF signal in the sampled erasing period becomes constant. The control of the erasure level value E is performed, and the peak level value P and the bottom level value B are controlled based on the ε value set in accordance with the characteristics of the disc with respect to the erasure level value E. An automatic adjustment operation is performed. Such a sampling operation or servo operation can be performed by using a well-known sampling circuit or servo circuit, and the details thereof will be omitted.

  As described above, the optical disk recording / reproducing apparatus according to the present invention is configured. Next, a laser output setting method which is the gist of the present invention will be described. Data information representing the characteristics of the disk is extracted based on an ATIP signal obtained from a pre-groove provided on the disk, and an erase level value E set according to the recording characteristics of the disk from the extracted data information, The peak level value P, the bottom level value B, and the ε value are recognized.

  When such a setting operation is performed, the optical pickup is moved to the test writing area provided on the inner peripheral side of the disc and the test signal recording operation is performed on the test writing area while changing the laser output. . In the present invention, the laser output changing operation is performed by changing the peak level value P while the erase level value E is fixed. That is, in the conventional technique, the test signal is recorded while correcting and changing the peak level value P and the bottom level value B based on not only the erase level value E but also the ε value. The test signal recording operation is performed by changing the peak level value P.

When the test signal recording operation is completed by changing the preset peak level value P, the optical pickup is moved to the position where the test signal recording operation is started, and then the test signal is reproduced. The recording quality detection circuit 11 detects the recording quality of the reproduced signal. In this embodiment, the recording quality detection circuit 1
1, the recording quality detection operation is performed based on the number of errors included in the reproduction signal.

  The test signal recorded in the test writing area is reproduced by the above-described operation, and if there is an error in the reproduced signal, an error correction operation by the error correction circuit incorporated in the digital signal processing circuit 5 is performed. The recording quality detection circuit 11 counts the number of errors corrected by the error correction circuit in correspondence with the recorded signal by changing the peak level value P, and detects the change in the count number. A peak level value P suitable for recording operation can be set.

  A test signal is recorded while stepwise changing the value of the multi-pulse peak level value P, which is a drive signal supplied to the laser diode 1, and the recorded test signal is reproduced. When the number of error correction operations performed on the reproduction signal of the test signal recorded corresponding to is counted, the count number gradually decreases from a large number and gradually increases from a certain point. A reproduction signal with the smallest number of error corrections is immediately before the number of errors changes from decrease to increase, and the peak level value P on which this signal is recorded is the most suitable peak for recording a signal on a disc to be used. It becomes the level value P.

  When the peak level value P constituting the multi-pulse is set in this way, the erase level value E and the bottom level value B are set based on the ε value suitable for the recording characteristics of the disc with the peak level value P as a reference. Then, control operations are performed on the peak level signal output circuit 7, the bottom level signal output circuit 8, and the erase level signal output circuit 9 so as to generate a multi-pulse drive signal suitable for performing the recording operation.

  As described above, the generation control operation of the laser drive signal suitable for driving the laser diode 1 is performed, but the control circuit 6 performs the selective addition control operation of the adder circuit 10 in accordance with the input recording signal. A signal subjected to selective addition control is supplied to the laser driving circuit 2. As a result, a drive signal having a waveform shown in FIG. 2 from the laser drive circuit 2, that is, a pulse waveform consisting of a peak level value P and a bottom level value B is supplied to the laser diode 1 during the recording period, and a drive signal having an erase level value B is supplied. It is supplied to the laser diode 1 during the erase period. Then, the recording period and the erasing period in which the laser driving signal having such a pulse waveform is output are changed according to the length of the recording signal.

  Although the detection operation by the recording quality detection circuit 11 in the embodiment described above is performed by detecting the number of errors included in the reproduction signal, the recording quality can also be detected by the β value. Here, the β value will be described. FIG. 3 is a waveform diagram of an RF signal obtained by reproducing a signal recorded on the disc, and A1 and A2 are a positive peak level and a negative peak level, respectively.

  Under such conditions, the β value is expressed as β = (A1 + A2) / (A1−A2), and when the β value is a specified value, a signal is recorded with an optimum laser output. Is set by. Therefore, the recording quality detection operation can be performed by detecting the β value of the test signal recorded in the test writing area. Further, it is possible to determine the recording quality by detecting whether or not the amplitude value of the RF signal is at an optimum value set in advance.

1 is a circuit diagram showing an embodiment of an optical disc recording / reproducing apparatus according to the present invention. It is a wave form diagram of a laser drive pulse signal used for the present invention. It is a wave form diagram for demonstrating operation | movement of this invention.

Explanation of symbols

1 Laser diode
2 Laser drive circuit
3 Photodetector
4 RF signal amplification circuit
6 Control circuit
7 Peak level signal output circuit
8 Bottom level signal output circuit
9 Erasing level signal output circuit 10 Adder circuit 11 Recording quality detection circuit

Claims (4)

The test signal is recorded in the test writing area provided on the disc while changing the laser output, and the laser output suitable for the recording operation is set by detecting the recording quality of the recorded test signal, and the erase level value is set. In an optical disc recording / reproducing apparatus configured to perform a recording operation by driving a laser diode with a multi-pulse consisting of a peak level value and a bottom level value, the laser output setting operation is performed with the erase level value fixed. A laser output setting method for an optical disc recording / reproducing apparatus, wherein the setting is performed by changing a peak level value. 2. The laser output setting method according to claim 1, wherein after the peak level value suitable for the recording operation is set by the recording quality detection operation, the erasure level value and the bottom level value are set. 2. The laser output setting method according to claim 1, wherein the recording quality detection operation is performed based on the number of errors in the reproduction signal. 2. The laser output setting method according to claim 1, wherein the recording quality detection operation is performed based on a [beta] value.

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