JP2002117543A - Method for controlling laser output of optical disk recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk recording and reproducing device capable of recording a signal on the disk by the irradiation of a laser emitted from an optical pickup. SOLUTION: In the optical disk recording and reproducing device which is constituted so as to set the laser output by recording a test signal on the trial writing area arranged on the disk 3 while changing the laser output and by reproducing the recorded test signal, the test signal is recorded while changing the recording pulse waveform and also the recorded signal is reproduced, then the laser driving condition is set by measuring the amplitude of an RF signal which is the reproduced signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording / reproducing apparatus configured to record a signal on a disk by a laser radiated from an optical pickup and to reproduce a signal recorded on the disk by the laser. About.

[0002]

2. Description of the Related Art Disk players that use an optical pickup to reproduce a signal recorded on a disk have become widespread, but recently, in addition to a reproduction function, a disk irradiated by a laser emitted from the optical pickup has been used. An optical disk recording / reproducing apparatus configured to record a signal on the optical disk has been commercialized.

In such an optical disk recording / reproducing apparatus, pits are formed on a disk by a laser. However, when the output of the laser is not optimal, the pit shape may be too large or too small. Will do. Therefore, a disk used in such an optical disk recording / reproducing apparatus is provided with a test writing area on the innermost side, and after recording a signal in the test writing area, reproducing the signal, and detecting the reproduced signal. Is configured to set a laser output for recording by using such a technique. For example, such a technique is disclosed in Japanese Patent Application Laid-Open No. 6-76288.

[0004]

In order to accurately record a signal on a disk, it is necessary to set not only the laser output but also the recording pulse waveform according to the characteristics of the disk. A conventional optical disk recording / reproducing apparatus is configured to set a recording pulse waveform based on data stored in a memory circuit in accordance with characteristics of a commercialized disk.

[0005] However, the characteristics of commercially available disks vary even if the disks are of the same type, so that the recording pulse waveform set based on the stored data can be said to be optimal. Absent. Further, when a new disk is commercialized, there is a problem that an accurate recording operation cannot be performed because data for outputting a recording pulse waveform matching the characteristics of the disk is not stored.

An object of the present invention is to provide a laser output control method which solves such a problem.

[0007]

According to the present invention, a test signal is recorded in a test writing area provided on a disc while changing the laser output, and the laser output is set by reproducing the recorded test signal. In an optical disc recording / reproducing apparatus, a test signal is recorded while changing a recording pulse waveform, and the recorded signal is reproduced,
The laser driving conditions are set by measuring the amplitude of the RF signal that is the reproduced signal.

[0008]

FIG. 1 is a block circuit diagram showing an embodiment of an optical disk recording / reproducing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a turntable which is driven to rotate by an electric motor 2 and on which a disk 3 is placed, and 4 denotes a laser element which irradiates a light beam onto the disk 3 and which is reflected from a signal surface of the disk 3. This is an optical pickup incorporating a photodetector for receiving a light beam.

Reference numeral 5 denotes an RF signal amplifier circuit for amplifying an RF signal obtained from a photodetector incorporated in the optical pickup 4 and shaping the waveform, and 6 denotes a signal obtained via the RF signal amplifier circuit 5. A focusing control operation for focusing a light beam projected from the optical pickup 4 on a signal surface of the disk 3 on the basis of the light beam, a tracking control operation for causing the light beam to follow a signal track on the signal surface, and The pickup control circuit performs a control operation of a track jump operation for moving to a track or the like, and incorporates a servo circuit that controls a focusing operation and a tracking operation. Reference numeral 7 denotes a servo control circuit for controlling the gain of a servo circuit incorporated in the pickup control circuit 6.

Reference numeral 8 denotes a digital signal processing circuit which receives a signal output from the RF signal amplifying circuit 5 and performs digital signal processing of the signal to demodulate various signals, and 9 denotes a digital signal processing circuit. 8 is a signal reproducing circuit to which a digital signal processed in 8 is input. If the information recorded on the disk 3 is an audio signal, the signal is converted into an analog signal and then output to an amplifier or the like. In the case of a data signal such as software, the function is to output the digital signal as it is to the computer device.

Reference numeral 10 denotes an operation switch section in which operation switches for operation switching, which are operated when switching the operation of the optical disk recording / reproducing apparatus, are incorporated. Reference numeral 11 denotes an input of a signal demodulated by the digital signal processing circuit 8. And a system control circuit that performs various control operations in accordance with the operation of each operation switch incorporated in the operation switch unit 10, and stores data for setting a laser output value and a recording pulse waveform described later. Memory circuit (not shown) is incorporated. Reference numeral 12 denotes a motor drive circuit whose operation is controlled by the system control circuit 11, which has an operation of controlling the rotational drive of the motor 2 at a predetermined speed.

A laser driving circuit 13 for driving a laser element incorporated in the optical pickup 4;
Reference numeral 14 denotes a laser output control circuit whose operation is controlled by the system control circuit 11, which is configured to control the laser drive circuit 13 to control the laser output. Reference numeral 15 denotes a recording signal input and the laser driving circuit 1 corresponding to the signal.
3 is a signal recording circuit for recording a signal on the disk 3 by controlling the laser irradiation operation by the laser 3. Reference numeral 16 denotes a recording waveform setting circuit for setting the waveform of a recording pulse signal output from the laser driving circuit 13, and the operation thereof is controlled by the system control circuit 11.

Reference numeral 17 denotes an amplitude measuring circuit which receives the signal output from the RF signal amplifier circuit 5 and measures the amplitude of the signal. The measured output is input to the system control circuit 11. Is configured.

In such a circuit configuration, when the disk 3 is inserted into the disk mounting portion provided in the recording / reproducing apparatus in order to perform a signal recording operation, a laser output and a recording pulse waveform setting operation are performed. Such a laser output control setting operation is performed by performing a recording operation of a test signal in a test writing area provided on the innermost peripheral side of the disk 3 and a reproducing operation of the recorded test signal. Details will be described later.

A laser output and a recording pulse waveform are set by a recording / reproducing operation of a test signal in a test writing area.
The operation of recording a signal in the data signal recording area provided on the disc is started by the output of the laser element driven based on the driving conditions set in this way, but the signal recording operation is performed. In this case, the value of the drive current supplied from the laser drive circuit 13 to the laser element is changed by monitoring the change in the light reflected from the disk 3 so that the laser output is always adjusted to the optimum laser output for the recording operation. It is configured as follows.

As described above, the optical disk recording / reproducing apparatus according to the present invention is configured. Next, the reproducing operation in the circuit configured as described above will be described. When a reproduction operation switch provided on the operation switch section 10 is operated, a control operation for a reproduction operation by the system control circuit 11 is started. When performing such a reproducing operation, the laser element incorporated in the optical pickup 4 includes:
The drive current for obtaining a laser output for performing a reading operation of a signal recorded in the data signal recording area is set so as to be supplied from the laser drive circuit 13.

When the control operation for such a reproduction operation is started, the rotation control operation of the electric motor 2 by the electric motor drive circuit 12 is performed, and the focus control operation and the tracking control operation of the optical pickup 4 are started. The operation of reading a signal from the disk 3 by the optical pickup 4 is started. The rotating operation of the disk 3 during such a reproducing operation is performed at a constant linear velocity or a constant angular velocity.

The signal read by the optical pickup 4 is input to a digital signal processing circuit 8 through an RF signal amplifying circuit 5 to perform a signal demodulation operation. The signal processing operation and the like are performed by rotating a disk. The control operation is performed in correspondence with the control operation in which the linear velocity is constant or the angular velocity is constant. When signal processing is performed by the digital signal processing circuit 8 to extract information data, the information data is subjected to signal processing such as error correction and then applied to a signal reproduction circuit 9.

When the information data read from the disk 3 is an audio signal, the signal reproducing circuit 9 converts the data into an analog signal and outputs the analog signal to an amplifier or the like. In this case, the digital signal is output as it is to the computer device.

As described above, the reproducing operation in this embodiment is performed. Next, the signal recording operation will be described. When the recording disk 3 is inserted into the mounting portion of the disk, a laser output and a recording pulse waveform setting operation are performed by a recording / reproducing operation of a test signal to a test writing area described later.

When the laser output and the recording pulse waveform are set by the recording operation of the test signal in the test writing area and the reproduction operation of the test signal, the recording operation of the signal input from the signal recording circuit 15 starts. Is done. Such a signal recording operation is performed on a data signal recording area provided on the disk 3.

In the state where such a recording operation is being performed,
Since the temperature of the optical pickup 4 changes, the output of the laser and the wavelength of the laser change, and the recording characteristics for the disk 3 change. When the recording characteristics of the disk 3 change, the light reflected from the disk surface changes, so that the laser drive circuit 13 corrects the change.
The servo circuit incorporated in the disk 3 operates, and the recording operation of the signal on the disk 3 can be performed continuously with the optimum laser output value.

The signal recording operation is released by operating a recording stop switch provided in the operation switch section 10. However, the termination of the recording operation depends on the signal recording position and the like. It is configured to be completed by recording the indicated position information data or the like at a predetermined position. That is, a reproduction operation of a desired signal can be started by using such position information data, and a setting operation of a position at which a next recording operation is started can be performed.

The signal recording operation is performed as described above. Next, the laser output control method which is the gist of the present invention will be described. When a recording disk is mounted on the disk mounting portion, a laser output control operation is started. The laser output control operation is performed by changing and setting a recording pulse waveform by the recording waveform setting circuit 16 and recording the same. After the test signal is recorded in the test writing area by changing the laser output continuously or stepwise for each pulse waveform, the recorded test signal is reproduced and the amplitude of the reproduced RF signal is measured. The measurement is performed by the circuit 17.

The measured amplitude value changes in accordance with the change in the laser output, and the system control circuit 1 determines the change rate and the linearity of the amplitude change.
Perform by 1. There is such a characteristic that the change in the measured amplitude value of the test signal recorded with the recording pulse waveform most suitable for the characteristics of the disk 3 used is large, and the change is also performed linearly. Accordingly, the recording pulse waveform in which the change in the amplitude measurement value is large and the change is made linearly is selected as the optimum recording pulse waveform, and the data is stored in the memory circuit incorporated in the system control circuit 11. . In this way, the signal recording operation to the data signal recording area is performed based on the data stored in the memory circuit.

As described above, the laser output control operation is performed. However, the servo gain of the focus servo circuit and the servo gain of the tracking servo circuit incorporated in the pickup control circuit 6 are controlled by the servo control circuit 7. It is done according to the change. By performing such a servo gain control operation, the operation of recording the test signal in the test writing area and the operation of reproducing the test signal recorded on the disk 3 can be performed accurately.

An RF signal, which is a reproduction signal of the test signal,
The amplitude measurement operation of the signal is performed by the amplitude measurement circuit 17. When the amplitude measurement is performed, the amplitude of the target signal can be accurately measured by performing the measurement operation on the band-limited signal. That is, by incorporating a filter circuit and an equalizer circuit in the amplitude measuring circuit 17, unnecessary signals such as noise signals can be removed, and accurate amplitude measurement can be performed.

[0028]

According to the present invention, a test signal is recorded in a test writing area provided on a disk while changing the laser output, and the laser output is set by reproducing the recorded test signal. The optical disk recording / reproducing apparatus records a test signal while changing the recording pulse waveform, reproduces the recorded signal, and sets the driving condition of the laser by measuring the amplitude of the RF signal as the reproduced signal. As a result, a recording pulse waveform that matches the recording characteristics of the disk used can be set.

Further, according to the present invention, the laser driving condition is set by detecting a change in the measured amplitude, so that the recording pulse waveform can be set accurately.

In the present invention, the driving condition of the laser is set by recognizing the rate of change of the amplitude, so that the operation of selecting the recording pulse waveform can be easily performed.

[Brief description of the drawings]

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

[Explanation of symbols]

 Reference Signs List 1 turntable 3 disk 4 optical pickup 5 RF signal amplification circuit 6 pickup control circuit 8 digital signal processing circuit 11 system control circuit 13 laser drive circuit 14 laser output control circuit 16 recording waveform setting circuit 17 amplitude measurement circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D090 AA01 BB03 BB04 CC01 CC04 CC18 DD03 EE01 HH01 JJ12 KK03 5D119 AA23 BA01 DA01 DA05 HA16 HA17 HA19 5F073 BA05 GA02 GA12 GA24

Claims (4)

[Claims] 1. A test signal is recorded in a test writing area provided on a disk while changing a laser output.
In an optical disc recording / reproducing apparatus configured to set a laser output by reproducing a recorded test signal, a test signal is recorded while changing a recording pulse waveform, and the recorded signal is reproduced, and the reproduction is performed. A laser output control method for an optical disk recording / reproducing apparatus, wherein a laser driving condition is set by measuring an amplitude of an RF signal as a signal. 2. The laser output control method according to claim 1, wherein the recording operation of the test signal is performed while changing the laser output every time the recording pulse waveform is changed. 3. The laser output control method according to claim 2, wherein a driving condition of the laser is set by detecting a change in the measured amplitude. 4. The laser output control method according to claim 3, wherein the driving condition of the laser is set by recognizing a rate of change of the amplitude.