JP2002230767A - Laser control method 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 recording operation with two or more recording rates can be performed, a laser servo circuit 12 to control an operation of a laser driving circuit 9 which supplies a driving current to a laser element is provided, and while adjusting the rise-time characteristics by changing a gain of the servo circuit, a reference laser output to carry out adjustment operation is changed in accordance with each recording velocity.

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 of the laser beam is not optimal, the pit shape is too large or small. Too much. 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 the laser power for recording by
Such a technique is disclosed in, for example, JP-A-6-76288.

[0004]

The operation of recording a signal on a disk is performed by forming a pit on a signal track provided on the disk by a laser beam output from a laser element. Is set to be 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] The write-once optical disk recording / reproducing apparatus has a characteristic that a signal recording operation can be performed only once at the same location of a recording area provided on the disk. Therefore, in such an optical disc recording / reproducing apparatus, when performing a signal recording operation, it is configured to recognize the position where the signal is recorded up to the previous time and start the signal recording operation from the position after the position. ing. A link between the previous recording end position and the signal recording start position is called a link, and it is required to narrow the link portion.

However, due to the delay of the rising characteristics of the laser element incorporated in the optical pickup, no signal is recorded in the link portion, that is, an unrecorded portion is formed. In this case, there is a problem that when performing the signal reproducing operation, the signal reproducing characteristics are adversely affected. In order to solve such a problem, a method of overlapping a previous recording end position and a signal recording start position is adopted.

FIG. 3 is an explanatory diagram showing a signal recording position of a disk when a signal recording operation is performed by a method of overlapping a previous recording end position and a signal recording start position. Indicates the portion recorded by the recording operation described above, and T3 indicates the recording start position of the next signal. As is clear from the figure, the portion from T3 to T2 is the link portion, and the signal is recorded twice.

In this case, since the link portion is double-recorded, there is no unrecorded portion, and the adverse effect on the reproduction characteristics is reduced. Become. Therefore, there is a problem that the synchronization of the PLL is disrupted when performing the signal reproducing operation.

When the recording operation is resumed after the interruption of the recording operation, it is required to start the recording operation so as to continue the signal recorded before the interruption of the recording operation. It is necessary to adjust characteristics so as to be in an optimum state. The rising characteristics of such a laser element can be made optimal by adjusting the gain of a laser servo circuit provided for driving the laser element. Conventionally, such adjustment of the rising characteristics of the laser element is performed by using a specific laser output, so that an optimal adjustment operation for each recording speed cannot be performed.

An object of the present invention is to provide a laser control method for an optical disk recording / reproducing apparatus which solves such a problem.

[0011]

According to the present invention, a signal is recorded on a disk after adjusting the output of laser light emitted from a laser element by performing a test signal recording operation on a test writing area provided on the disk. An optical disk recording / reproducing apparatus configured to be capable of performing a recording operation at a plurality of recording speeds and having a laser servo circuit for controlling an operation of a laser drive circuit for supplying a drive current to a laser element; The rise characteristics are adjusted by changing the gain, and the reference laser output for performing the adjustment operation is changed corresponding to each recording speed.

[0012]

1 is a block circuit diagram showing an embodiment of an optical disk recording / reproducing apparatus according to the present invention, and FIG. 2 is an explanatory diagram showing signal recording positions for explaining the operation of the present invention.
In FIG. 1, reference numeral 1 denotes a disk which is mounted on a turntable (not shown) which is driven to rotate by a spindle motor (not shown) and which is driven to rotate by the rotation of the turntable. The recording is performed by a groove called a groove, and a signal recording / reproducing operation is performed based on a wobble signal obtained from the groove. Reference numeral 2 denotes a laser element for irradiating the disk 1 with laser light, and a monitoring diode for monitoring the laser light emitted from the laser element is incorporated, and a photodetector for receiving the laser reflected from the signal surface of the disk 1 An optical pickup incorporated therein, which is configured to be displaced in the radial direction of the disk 1.

Reference numeral 3 denotes an RF signal amplifying circuit that amplifies an RF signal obtained from a photodetector incorporated in the optical pickup 2 and shapes the waveform, and 4 denotes a signal obtained through the RF signal amplifying circuit 4. Laser light emitted from the optical pickup 2 based on the
And a pickup control circuit that performs a focusing control operation for focusing on the signal surface of the optical disk and a tracking control operation for causing the laser light to follow a signal track on the signal surface.

Reference numeral 5 denotes a digital signal processing circuit that performs digital signal processing on the signal output from the RF signal amplifier circuit 3 and performs a demodulation operation of various signals, and 6 denotes a digital signal processed by the digital signal processing circuit 5. A signal reproducing circuit to which a signal is input. When the information recorded on the disc 1 is an audio signal, the signal is converted into an analog signal and then output to an amplifier or the like, and when the data signal is data such as computer software. Has the function of outputting the digital signal to the computer device 7 as it is.

Reference numeral 8 denotes a system control circuit which receives a signal demodulated by the digital signal processing circuit 5 and performs various control operations in response to an operation switching control signal output from the computer device 7. Disc 1
A memory circuit M in which a program for recording a test signal and data for controlling a laser output and the like are stored in a test writing area provided in the memory circuit M is incorporated.

Reference numeral 9 denotes a laser drive circuit for supplying a drive signal to a laser element incorporated in the optical pickup 2, and 10 denotes a laser output control circuit whose operation is controlled by the system control circuit 8. The laser output is set by controlling the circuit 9. A signal recording circuit 11 receives a recording signal such as a test signal or an information signal and controls a laser light irradiation operation by the laser driving circuit 9 in accordance with the signal to record the signal on the disk 1. It is.

Reference numeral 12 denotes a laser servo circuit for controlling a drive signal supplied from the laser drive circuit 9 to the laser element. The laser servo circuit 12 controls the laser based on a signal obtained from a monitor diode incorporated in the optical pickup 2. It is configured to perform a control operation of a drive signal supplied to the element and to control a gain or the like by a control signal output from the system control circuit 8.

In such a configuration, the rotational drive control operation of the disk by the spindle motor is configured to be able to be performed at a plurality of linear velocities set several times higher than a prescribed linear velocity. Each circuit is configured to perform a recording control operation according to each speed. The laser output serving as a reference for adjusting the gain of the servo operation by the laser servo circuit 12 is configured to be changed based on the data stored in the memory circuit M corresponding to each recording speed. I have.

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 switching signal output from the computer device 7 is input to the system control circuit 8, a control operation for a reproduction operation by the system control circuit 8 is started. When such a reproducing operation is performed, a driving current for obtaining a laser output for performing a signal reading operation is supplied from the laser driving circuit 9 to the laser element incorporated in the optical pickup 2. Is set to

When the control operation for such a reproducing operation is started, a rotation control operation of a spindle motor is performed by a spindle motor drive circuit (not shown), and a focusing control operation and a tracking control operation of the optical pickup 2 are performed. Is started, and the reading operation of the signal from the disk 1 by the optical pickup 2 is started. The signal read by the optical pickup 2 is input to the digital signal processing circuit 5 through the RF signal amplification circuit 3, and the signal is demodulated. When signal processing is performed by the digital signal processing circuit 5 to extract information data, the information data is applied to a signal reproduction circuit 6 after signal processing such as error correction is performed.

When the information data read from the disc 1 is an audio signal, the signal reproducing circuit 6 converts the information data into an analog signal and outputs the analog signal to an amplifier or the like. In this case, the digital signal is output to the computer 7 as it is.

In such a circuit configuration, when the disc 1 is inserted into the mounting portion of the disc in order to perform a signal recording operation, a laser output setting operation is performed. Such a laser output setting operation is performed based on a program stored in a memory circuit M provided in the system control circuit 8. The operation of setting the laser output is performed by, for example, stepping the magnitude of the drive current supplied from the laser drive circuit 9 to the laser element incorporated in the optical pickup 2 by the control signal output from the laser output control circuit 10. This is performed by recording a test signal while changing the frequency and reproducing the recorded signal.

When the magnitude of the drive current supplied to the laser element is changed stepwise, the output of the laser light output from the laser element changes, so that the level of the signal recorded on the disk 1 also changes. Become. Then, the level of the signal recorded on the disc 1 with respect to the laser output is detected, and when the level of the signal to be reproduced reaches a desired value, the laser output at that time is set as the laser output for performing the recording operation. Such an operation of setting the laser output is performed for each recording speed, and data for obtaining the set output is stored in the memory circuit M.

The recording operation of the data signal in the signal recording area is started by the laser output set in this manner. When the recording operation of the data signal is performed, the laser reflected from the disk 1 The operation of adjusting the value of the drive current supplied from the laser drive circuit 9 to the laser element by monitoring the change in the light so that the laser output always becomes optimal for the recording operation is performed. I have.

As described above, the recording operation of the test signal in the test writing area and the recording operation of the data signal in the signal recording area are performed. In order to perform the recording operation, the laser driving circuit 9 outputs the laser element. The control operation by the laser servo circuit 12 is always performed with respect to the drive signal supplied to.

As described above, the setting operation of the laser output is performed by the operation of recording and reproducing the test signal in the test writing area. Next, the laser control method which is the gist of the present invention will be described.

The present invention is configured to adjust the gain of the laser servo circuit 12 using a laser output suitable for each recording speed set at the time of a test signal recording operation in the test writing area as a reference laser output. Such an adjusting operation is performed while changing the rising characteristic of the laser element, and when performing the recording operation of the test signal, a gap between the test signal and the test signal is detected, and the rising characteristic becomes the narrowest gap. And the reproduction characteristics of the recorded signal are adjusted to an appropriate state. Such a change in the rise characteristic is performed by the laser servo circuit 12.
Can be performed by changing the gain.

In this manner, the operation of adjusting the rising characteristics of the laser element is performed. By performing the setting operation of the timing for starting the signal recording operation based on the rising characteristics thus set, the link operation is performed. The signal recording operation can be performed in a state where the length of the portion is minimized. FIG. 2 shows a positional relationship of a recording signal when recording is performed in a state where such adjustment is performed, and a region where a data signal is recorded by a previous recording operation is from T1 to T2. . The position at which the signal recording operation is started following the disk 1 recorded in this way is T3, and it is possible to make T2 and T3 substantially coincide.
That is, since the double recorded portion and the unrecorded portion can be reduced as much as possible, not only can the recording area of the disk 1 be used effectively, but also the recording operation can be performed without any trouble in the reproducing operation. Can be done.

Further, since the above-described operation is performed, when the recording interruption and the resuming operation are performed during the recording operation, the signal recorded before the recording interruption and the signal recorded after the recording resumption are made continuous. Can be recorded.

Further, if the adjusting operation for changing the rising characteristic of the laser beam is performed by changing the characteristic from a gradual characteristic to a steep characteristic direction, the drive current flowing through the laser element can be suppressed. The risk of damaging is reduced.

[0031]

According to the present invention, a signal is recorded on a disk after the output of a laser beam emitted from a laser element is adjusted by performing a test signal recording operation on a test writing area provided on the disk. An optical disc recording / reproducing apparatus that is configured and configured to be able to perform a recording operation at a plurality of recording speeds,
A laser servo circuit is provided to control the operation of the laser drive circuit that supplies the drive current to the laser element.The gain of the servo circuit is changed to adjust the rise characteristics and perform the adjustment operation. Since it is changed correspondingly, it is possible to control the laser output characteristics to be optimal for each recording speed. As described above, according to the present invention, the output characteristics of the laser can be optimized for each recording speed, so that when the recording restart operation is performed after the recording interruption operation, the area recorded before the recording interruption is performed. This has the effect of minimizing the connection between the area to be recorded at the start of recording and the area to be recorded.

Further, according to the present invention, the rising characteristic of the laser beam is adjusted by changing the rising characteristic from a gradual characteristic to a steep characteristic direction.
The driving current flowing through the laser element can be suppressed, and as a result, the risk of damaging the laser element can be reduced.

According to the present invention, the recording start timing is set in accordance with the rising characteristic of the laser beam, so that the area between the area recorded by the previous recording operation and the area recorded next is set. Since the double recorded part and unrecorded part of a certain connecting part can be reduced as much as possible,
A recording operation capable of performing a reproducing operation without any trouble can be 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 control method of the present invention.

FIG. 2 is an explanatory diagram showing signal recording positions for explaining the operation of the present invention.

FIG. 3 is an explanatory diagram showing signal recording positions for explaining a conventional recording operation.

[Explanation of symbols]

 Reference Signs List 1 disc 2 optical pickup 3 RF signal amplification circuit 4 pickup control circuit 5 digital signal processing circuit 7 computer device 8 system control circuit 9 laser drive circuit 10 laser output control circuit 12 laser servo circuit

Continued on the front page F term (reference) 5D090 AA01 BB03 CC01 FF11 KK03 KK20 5D119 AA22 BA01 BB02 HA19 HA45 5F073 BA06 EA28 GA02 GA12 GA38

Claims (3)

[Claims] 1. A signal is recorded on a disk after a laser signal output from a laser element is adjusted by performing a test signal recording operation on a test writing area provided on the disk. And a laser servo circuit for controlling the operation of a laser drive circuit for supplying a drive current to a laser element in an optical disc recording / reproducing apparatus configured to be able to perform a recording operation at a plurality of recording speeds. A laser control method for an optical disc recording / reproducing apparatus, wherein a reference laser output for performing an adjusting operation and a reference laser output is changed corresponding to each recording speed. 2. The laser control method according to claim 1, wherein the rising characteristic of the laser beam is adjusted by changing the rising characteristic of the laser light from a gentle characteristic to a steep characteristic direction. 3. The laser control method according to claim 1, wherein the recording start timing is set in accordance with the rising characteristics of the laser light.