JP2002230768A - Laser output control circuit 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 a disk with laser irradiated from an optical pickup. SOLUTION: In the optical disk recording and reproducing device constituted so that the laser output most suitable for a recording operation may be set by recording a test signal on a trial writing region prepared to the disk and constituted so that the recording operation with two or more recording rates can be performed, while setting the optimum laser output for every recording rate, the optimum laser output is stored for every recording rate, and when the switching operation to recording operating state is performed, the optimum laser output corresponding to the recording rate set when setting the optimum laser output is supplied to the laser driving circuit.

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 apparatus which records a signal on a disc by a laser beam emitted from an optical pickup and reproduces a signal recorded on the disc by the laser beam. It relates to a playback device.

[0002]

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

In such an optical disk recording / reproducing apparatus, pits are formed on a disk by a laser beam. However, if the output level of the laser beam is not optimal, the pit shape may be too large. It will be too small. 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. The laser output for recording is set according to the method described in JP-A-6-7628.
No. 8 discloses a technique disclosed in Japanese Patent Publication No.

[0004]

The operation of recording a signal on a disk is performed by alternately switching the output level of laser light output from a laser element between a recording level and a reproduction level. That is, the recording is performed by forming pits on a signal track provided on the disk by using a laser beam for recording output, and the size of the pits is set to a specified size. The recording operation of such a signal is performed by rotating the disk at a predetermined constant linear velocity, but recently, the recording operation is performed with the linear velocity during the recording operation being several times the predetermined velocity. An optical disk recording / reproducing device capable of performing such operations has been commercialized.

[0005] In a write-once optical disk recording / reproducing apparatus, when performing a switching operation from a reproducing state to a recording state, a switching speed corresponding to a servo operation of a servo circuit incorporated in a laser drive circuit is required. Then, as the recording speed of the signal on the disc increases, it is necessary to perform the switching operation from the reproduction state to the recording state in a short time,
In particular, when the recording operation is temporarily interrupted and then resumed, it is required that the recording operation with the optimal laser output be instantaneously resumed.

In order to perform such a switching operation in a short time, a method of increasing the gain of a servo circuit is adopted. However, a phenomenon called overshoot occurs in a recording waveform at the start of recording, and an optimum recording operation is performed. It takes a long time to start recording, and there is a problem that a recording signal is abnormal.

An object of the present invention is to provide a laser output control circuit of an optical disk recording / reproducing apparatus which solves the above problem.

[0008]

According to the present invention, a laser signal optimum for a recording operation is set by recording a test signal in a test writing area provided on a disk. In an optical disc recording / reproducing apparatus configured to be capable of performing a recording operation at a speed, an optimum laser output is set for each recording speed, and the set optimal laser output is stored for each recording speed. When the operation for switching to the state is performed, the optimum laser output corresponding to the recording speed set at the time of setting the optimum laser output is supplied to the laser drive circuit.

[0009]

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

In FIG. 1, reference numeral 1 denotes a laser diode which is incorporated in an optical pickup and irradiates a laser beam, and is connected so as to be driven by a current supplied from a laser driving circuit 2. I have. In such a circuit, during a recording operation,
The laser drive circuit 2 sends a pulse signal to the laser diode 1 as shown in FIG.
A pulse signal composed of R and a reproduction output VP is supplied.

Reference numeral 3 denotes a monitor signal input terminal to which a monitor signal obtained from a monitor diode (not shown) provided to monitor the laser light output from the laser diode 1 is input, and 4 denotes the laser diode. This is a sampling circuit for sampling the level of the recording output VR in the laser light output from the unit 1, and as shown in FIG. 2, samples the level during the recording output period and holds the level during the reproduction output period. Has an action. In the figure, S is a sampling operation period, and H is a sampling holding period.

Reference numeral 5 denotes a recording output setting circuit for outputting a reference signal based on data set as an optimal recording output during a recording operation of a test signal in a test writing area provided on the disk. Reference numeral 6 denotes a comparison signal input terminal which is a negative terminal connected to an output terminal of the sampling circuit 4 via a resistor 7, and a reference signal input terminal which is a + terminal outputs the output of the recording output setting circuit 5 A resistor 8 and a capacitor 9 are connected in parallel to a feedback circuit between an output terminal and a comparison signal input terminal. 10 is a recording switch,
It is connected between a comparison signal input terminal of the comparison circuit 6 and an output terminal of the comparison circuit 6.

The recording switch 10 is open when a recording operation is to be performed and a recording operation for setting an optimum laser output is to be performed, and switching from a reproduction state to a recording operation state is performed. Then, it is configured to be closed immediately and to maintain the closed state for a predetermined time.

Reference numeral 11 denotes a control circuit to which a signal output to the output terminal of the comparison circuit 6 is inputted. The control circuit 11 has an optimum laser output set by an operation of recording a test signal in a test writing area provided on a disk. And a memory circuit in which data for obtaining the data is stored. The operation of setting the optimum laser output is performed at each recording speed, and the set data is stored at each speed.

[0015] In such a configuration, by performing a recording operation of a test signal in a test writing area provided on the inner peripheral side of the disk, data capable of obtaining an optimum laser output for performing the recording operation is transmitted to the control circuit. 11, the setting operation of the optimum laser output can be performed by using the conventional technology.
The description is omitted.

When the data signal is being recorded in the recording area of the disk, the recording switch 10 is on the opposite side of the state shown in the figure, that is, in the open state, and the laser drive circuit 2 outputs the waveform shown in FIG. A pulse signal is output to the laser diode 1. And
In the state where such a recording operation is being performed, a sampling operation and a sampling holding operation for the recording output by the sampling circuit 4 are performed, and the signal is compared with a reference signal output from the recording output setting circuit 5. Since the output signal thus supplied is supplied to the laser drive circuit 2, a control operation for making the output of the drive signal supplied to the laser diode 1 optimal is performed. That is, a monitor signal obtained from a monitoring diode provided to monitor the laser light emitted from the laser diode 1 is input to the monitor signal input terminal 3, and a signal obtained by sampling the input signal and a recording output setting. The reference signal output from the circuit 5 is compared by a comparison circuit 6 and the compared signal is supplied to the laser drive circuit 2, so that a control operation for maintaining the laser output in an optimum state, a so-called servo operation Is performed. In this case, the laser output is determined and controlled by a signal supplied to the laser drive circuit 2 through a laser control circuit including a comparison circuit 6 and the like.

The operation of setting the optimum laser output by performing the operation of recording the test signal in the test writing area is as follows.
The operation is performed in a state where the recording switch 10 is switched to the opposite side to the illustrated state. Such an operation of setting the laser output is performed for each recording speed of the optical disk recording / reproducing apparatus. The obtained data is stored in a memory circuit provided in the control circuit 11 for each speed.

As described above, the operation of controlling the laser output in the case of performing the signal recording operation on the disk is performed. Next, the operation of switching from the reproduction state to the recording state in which the signal is recorded will be described. When the optical disk recording / reproducing apparatus is switched from a reproducing state to a state in which a recording operation is performed, the recording switch 10 is switched to a state shown in FIG.

When the recording switch 10 is closed, a signal output from the recording output setting circuit 5, that is, a signal capable of obtaining an optimum laser output, is output to the output terminal of the comparison circuit 6. This signal is supplied to the laser drive circuit 2. Therefore, the laser diode 1
After that, the laser beam of the optimum output is irradiated.

When the switching operation to the recording state is performed, the recording switch 10 is closed as described above, but after a predetermined time has elapsed, the recording switch 10 is opened. Even when the recording switch 10 is opened, the capacitor 9 is in a state where both ends are short-circuited by the recording switch 10. At the moment when the switching operation is performed, the charge of the capacitor 9 is zero. A signal corresponding to the reference signal output from the recording output setting circuit 5 is output to the output terminal 6. Then, as the charging of the capacitor 9 progresses, the state changes to a state of performing an output control operation of laser light emitted from the laser diode 1, that is, a servo operation, and a state of performing a recording operation.

After the switching operation of the recording switch 10 is performed, a servo operation based on a monitor signal obtained from the monitoring diode, that is, an automatic adjustment operation of the laser output is performed and the laser diode 1 emits light. The output control operation of the laser light is performed. When the switching operation to the recording operation state is performed as described above, the output of the laser light emitted from the laser diode 1 is started from an optimum level, so that the servo operation for controlling the output operation of the laser light is started immediately. Can be done. Therefore, the switching operation from the reproduction state to the recording state can be performed in a short time, and the switching operation corresponding to the increase in the recording speed on the disc can be performed without any trouble.

As described above, the laser output control operation is performed when the switching operation from the reproduction state to the recording state is performed, but the signal output from the recording output setting circuit 5 is controlled by the control circuit 11. Is determined by the control operation.
That is, the memory circuit incorporated in the control circuit 11 stores data for obtaining the optimum laser output for each recording speed set in the test writing area. As the signal output to the circuit 5, a signal corresponding to the recording speed during the recording operation is selected. Therefore, not only can an optimum laser output be obtained for each recording speed, but also if the recording speed switching operation is performed during the recording operation, the laser output can be changed according to the switching speed. The recording operation at all speeds can be performed with the optimum laser output.

In this embodiment, the case where the optimum laser output is set according to the recording speed has been described. However, it is also possible to set the optimum laser output according to the recording characteristics of the disk.

[0024]

According to the present invention, a laser signal optimal for a recording operation is set by recording a test signal in a test writing area provided on a disk, and a recording operation at a plurality of recording speeds is performed. In the optical disc recording / reproducing apparatus configured to perform the operation, the optimal laser output is set for each recording speed, and the set optimal laser output is stored for each recording speed, and the recording operation state is switched. When the operation is performed, the optimum laser output corresponding to the recording speed set at the time of setting the optimum laser output is supplied to the laser drive circuit. A state in which the recording operation by the above is accurately performed can be promptly configured. Therefore, according to the present invention, in the recording operation state, when the interruption operation and the recording resumption operation of the recording operation are repeatedly performed, the accurate return operation to the recording operation state can be promptly performed. Continuity can be maintained, and a recording operation with excellent characteristics can be performed.

[Brief description of the drawings]

FIG. 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 chart for explaining the operation of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser diode 2 Laser drive circuit 4 Sampling circuit 5 Recording output setting circuit 6 Comparison circuit 10 Recording switch 11 Control circuit

Claims (2)

[Claims] 1. A recording apparatus according to claim 1, wherein a test signal is recorded in a test writing area provided on the disk so that a laser output optimum for a recording operation is set and a recording operation at a plurality of recording speeds is performed. In an optical disc recording / reproducing apparatus configured to be able to perform the setting, an optimum laser output is set for each recording speed, the set optimum laser output is stored for each recording speed, and a switching operation to a recording operation state is performed. A laser output control circuit for an optical disc recording / reproducing apparatus, wherein an optimum laser output corresponding to a recording speed set when an optimum laser output is set is supplied to a laser drive circuit. 2. The laser output control circuit according to claim 1, wherein an automatic adjustment operation of the laser output is performed based on the optimum laser output after the recording operation is started.