JP2003281729A - Optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize recording power in accordance with a linear velocity when recording is carried out on an optical disk which has recording power linear velocity dependence while the linear velocity is changed. <P>SOLUTION: When recording is carried out on an optical disk which has recording power linear velocity dependence while a linear velocity is changed, the level of an RF signal or the level of the reflected light signal of a subbeam obtained during the recording is detected and, from this value, the recording power is optimized in accordance with the linear velocity. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc apparatus capable of recording an optical disc having a recording power linear velocity dependence while varying the linear velocity.

[0002]

2. Description of the Related Art When an optical disk having a linear velocity dependence of recording power is recorded while changing the linear velocity, it is necessary to increase the recording power as the linear velocity increases.

A conventional optical disk device is disclosed in, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Application Laid-Open No. 0-106009, when recording on an optical disc while changing the linear velocity, the bottom value of the reflected light amount from the optical disc in the recording power irradiation section is detected so that the bottom value becomes constant. , The recording power output from the optical pickup is controlled.

[0004]

The bottom value of the amount of light reflected from the optical disk in the recording power irradiation section depends on the recording power irradiated on the disk and the shape of the mark to be formed. Therefore, the bottom value is simply constant. Since the recording power is controlled so that the higher the recording power is required, that is, the higher the linear velocity is, the larger the mark shape needs to be, the recording state changes depending on the linear velocity. .

According to the present invention, when an optical disc having a recording power linear velocity dependence is recorded while changing the linear velocity,
An object of the present invention is to provide an optical disk device that can make the recording state of an optical disk uniform regardless of the linear velocity.

[0006]

The optical disk device of the present invention is an optical pickup which rotates an optical disk at an arbitrary linear velocity, irradiates the optical disk with an arbitrary recording power, and receives reflected light from the optical disk. In the provided optical disc device, first means for obtaining a peak value and a bottom value of a reflected light amount in a recording power irradiation section of the optical disc having a linear velocity dependence of the recording power, and a value obtained by normalizing the bottom value with the peak value. And a second means for controlling the recording power output from the optical pickup so that the value becomes a target value.

Further, the optical disk device of the present invention is an optical disk device equipped with an optical pickup for rotating the optical disk at an arbitrary linear velocity to irradiate the optical disk with an arbitrary recording power and receiving reflected light from the optical disk. In the recording power irradiation section of the optical disc in which the recording power has a linear velocity dependency, first means for obtaining the bottom value of the reflected light amount and the recording power value applied to the optical disc, and the bottom value as the recording power value. And a second means for controlling the recording power output from the optical pickup so that the value normalized by 1. becomes a target value.

In the optical disk device of the present invention, the optical disk is rotated at an arbitrary linear velocity to irradiate the optical disk with a main beam, a front sub-beam and a rear sub-beam, and to receive reflected light from the optical disk. In an optical disc device equipped with a pickup, a first means for obtaining the amount of reflected light by the front sub-beam and the amount of reflected light by the rear sub-beam, and a target value of the rear sub-beam reflected light signal level normalized by the front sub-beam reflected light signal level A second control for controlling the recording power output from the optical pickup so as to obtain a value
And means are provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In recent years, there has been an increasing demand for improving the recording speed of optical disks such as CD-Rs.
In the case of a CD-R, the recording linear density of information is constant, so that it is necessary to improve the linear velocity in order to improve the recording speed. However, if the linear velocity is simply increased by using the conventional recording method with a constant linear velocity (CLV method: Constant Linear Velocity), the rotation speed at the inner circumference of the disc increases, and the vibration of the optical disc device increases. , There is a possibility that the recording quality will be adversely affected.
In order to solve this problem, a recording method (CAV method: Cons) in which the rotation speed is constant regardless of the inner and outer circumferences of the disc.
tant Angular Velocity) has been adopted. In this method, since the rotation speed is kept constant, the linear velocity on the inner peripheral side of the disc is low and the linear velocity on the outer peripheral side of the disc is high. In the recording method in which the rotation speed is constant as described above, for example, in the case of an optical disk such as a CD-R in which the recording power depends on the linear speed, it is necessary to optimize the recording power according to the linear speed. .

According to the present invention, when an optical disk having a linear velocity dependence of recording power is recorded while changing the linear velocity,
Provided is a means for optimizing the recording power according to the linear velocity.

Hereinafter, each embodiment of the present invention will be described with reference to FIGS.
It will be described based on. (Embodiment 1) FIGS. 1 and 2 show (Embodiment 1) of the present invention.

In FIG. 1, reference numeral 1 is an optical disk, 2 is an optical pickup, and mainly comprises a laser diode 3, a laser driver 4, a diffraction grating 5, a beam splitter 6, an objective lens 7, a power detection circuit 8 and a light receiving element 9. Has been done.

The laser light output from the laser diode 3 is split into 0th-order light and 1st-order light by the diffraction grating 5,
The optical disk 1 is irradiated with light through the beam splitter 6 and the objective lens 7. The 0th-order light is called a main beam and contributes to reproduction of data recorded on the optical disc 1 and recording of data on the optical disc 1. The primary light is called a sub-beam, and is arranged in front of and behind the main beam in the rotation direction of the optical disc 1.

The laser driver 4 is a laser diode 3
Drive current is supplied to. The power detection circuit 8 receives the output light from the laser diode 3 that has passed through the beam splitter 6, and converts the received light amount into a voltage signal. The light receiving element 9 is, for example, a photo detector divided into eight,
The reflected light by the main beam and the sub beam with which the optical disk 1 is irradiated is received, and the received light amount is converted into a voltage signal.

The light receiving signal processing circuit 10 generates a focus error signal, a tracking error signal and an RF signal from the signal output from the light receiving element 9. Voltage detection circuit 1
1 is composed of, for example, a sample and hold circuit and an AD converter, and samples and holds the voltage signal output from the power detection circuit 8 or the RF signal output from the received light signal processing circuit 10 at a predetermined timing. The voltage value is digitally converted and detected by a microcomputer (hereinafter referred to as CPU) 12.

The encoder / decoder 13 encodes the data sent from the host computer, generates an optimum recording pulse according to the encoded data, and supplies the recording pulse to the laser driver 4, and at the same time, the voltage detection circuit 11 operates. A sample and hold pulse that determines the timing of sample and hold is generated and supplied to the voltage detection circuit 11.

The voltage generation circuit 14 is, for example, a DA converter, and supplies an arbitrary voltage set by the CPU 12 to the laser driver 4. The non-volatile memory 15 is
For example, it is a flash ROM, and the CPU 12
It is possible to save a predetermined value in addition to the program processed in.

Regarding control of recording power, part of the CPU 12 is constructed as follows. When recording information on the optical disc 1, the data to be recorded is encoded by an encoder /
Encoding is performed by the decoder 13 to generate a recording pulse suitable for the size of the mark to be recorded on the optical disc 1, and the recording pulse is supplied to the laser driver 4 mounted on the optical pickup 2. Furthermore, from the voltage generation circuit 14,
The voltage set by the CPU 12 is supplied to the laser driver 4.

In the laser driver 4, the voltage generation circuit 14
The laser current corresponding to the voltage output from the laser diode 3 is modulated by the recording pulse supplied from the encoder / decoder 13, and the modulated laser current is supplied to the laser diode 3.

Laser light is output from the laser diode 3 in accordance with the supplied laser current, and is radiated onto the optical disk 1 via the diffraction grating 5, the beam splitter 6, and the objective lens 7. A mark having a low reflectance is formed on the optical disc 1 by the main beam of the laser light with which the optical disc 1 is irradiated.

The reflected light from the optical disc 1 being recorded is received by the light receiving element 9, and the main beam component of the received light signal is added by the received light signal processing circuit 10 to generate an RF signal. For example, as shown in FIG. 2A, the RF signal waveform in the recording power irradiation section at the time of CD-R recording has a peak RF signal level because no mark is formed at the head position of the recording power irradiation section. It is known that since the mark starts to be formed toward the rear end of the recording power irradiation section, the level of the RF signal gradually decreases, and the RF signal level becomes the bottom value at the rear end position of the recording power irradiation section. Has been.

In the voltage detection circuit 11, the RF signal is
The peak value and the bottom value are sampled at the timings of the peak value sample and hold pulse (see FIG. 2B) and the bottom value sample and hold pulse (see FIG. 2C) supplied from the encoder / decoder 13, respectively. The sampled peak value and bottom value are AD-converted, and the result is obtained by the CPU 12.

The bottom value indicates the level of the amount of reflected light from the formed mark in the recording power irradiation section, and depends on the shape of the mark if the recording power for irradiation is constant. The peak value indicates the level of the amount of reflected light from the portion where no mark is formed, and is proportional to the recording power with which the optical disc 1 is irradiated.

If the bottom value of this RF signal is normalized by the peak value of the RF signal, the normalized value depends on the shape of the mark. Therefore, when the recording power is changed according to the linear velocity, if the recording power is controlled so that the value obtained by normalizing the bottom value with the peak value becomes the target value described later, specifically, the peak value and the When the recording power is controlled so that the ratio of the bottom value becomes the target value, uniform marks are formed on the optical disc 1 regardless of the linear velocity.

The target value is configured to be determined by the CPU 12 as follows. CD-R
In the case of a recordable optical disc such as the one described above, the PCA (Po
The optimum recording power is determined by trial writing in the wer calibration area). At this time, at the same time, the optimum value obtained by normalizing the bottom value with the peak value is acquired and stored in the nonvolatile memory 15.

When recording in the data area, the optimum value of the bottom value obtained in advance in the PCA area and normalized by the peak value is read out from the non-volatile memory 15, and the CPU 12 sets this value as the target value. The recording power is controlled as described above.

According to this configuration, the invention is not limited to recording at a constant rotation speed, but can be applied to a case where an optical disc is divided into a plurality of areas having different linear velocities and recorded. (Embodiment 2) In the above (Embodiment 1), when the recording power is changed according to the linear velocity, the recording power is controlled so that the value obtained by normalizing the bottom value with the recording power becomes the target value. Then, the CPU 12 is configured so that uniform marks are formed on the optical disc 1 regardless of the linear velocity.
First means for obtaining the bottom value of the amount of reflected light in the recording power irradiation section of the optical disc having the linear velocity dependence of the recording power and the recording power value irradiated on the optical disc, and the bottom value is normalized by the recording power value. The same effect can be obtained by providing the second means for controlling the recording power output from the optical pickup so that the converted value becomes the target value.

Specifically, in FIG. 1, a part of the laser light output from the laser diode 3 is transmitted through the beam splitter 6 and input to the power detection circuit 8,
A recording pulse waveform as shown in (d) is generated. From this recording pulse waveform, the voltage detection circuit 11 samples the recording power at the timing of the recording power sample hold pulse supplied from the encoder / decoder 13, and the sampled recording power is AD-converted, and the result is obtained. Is acquired by the CPU 12. If the bottom value of the RF signal is normalized by the detected recording power, the normalized value depends on the shape of the mark. Therefore, when the recording power is changed according to the linear velocity, if the recording power is controlled so that the value obtained by normalizing the bottom value with the recording power becomes the target value, it is possible to obtain a uniform value on the optical disc 1 regardless of the linear velocity. Marks can be formed.

In the case of a recordable optical disc such as a CD-R, trial writing is performed in a PCA (Power Calibration Area) area prepared in the innermost peripheral portion of the disc immediately before recording in the data area to obtain an optimum recording power. To decide. At this time, at the same time, the optimum value of the value obtained by normalizing the bottom value with the recording power is acquired. When recording in the data area, the bottom value acquired in the PCA area in advance is normalized by the recording power, specifically, the recording power is set with the ratio of the bottom value and the recording power as a target value. Control. Further, the optimum value of the value obtained by normalizing the bottom value with the recording power is stored, the value is called at an appropriate time, and the CPU 12 controls the recording power as described above with this value as a target value.

According to this structure, the invention is not limited to recording at a constant rotation speed, but can be applied to a case where an optical disc is divided into a plurality of areas having different linear velocities and recorded. (Embodiment 3) FIGS. 1, 3 and 4 show (Embodiment 3) of the present invention.

The overall structure is similar to that of the first embodiment, but only the specific structure of the pickup 2 and the specific structure of the CPU 12 for optimizing the recording power according to the linear velocity are different. .

Pickup 2 of this (Embodiment 3)
The laser light output from the laser diode 3 is split into a main beam, a front sub-beam and a rear sub-beam by the diffraction grating 5. Of these, the main beam contributes to the formation of marks on the optical disc 1, and the front sub-beam and the rear sub-beam are respectively arranged on the front outer peripheral side and the rear inner peripheral side of the main beam, as shown in FIG.

The reflected lights of the front sub-beam and the rear sub-beam are received by the corresponding photodetectors of the light receiving element 9, and the received light signal processing circuit 10 generates the front sub-beam reflected light signal and the rear sub-beam reflected light signal.

Since the front sub-beam traces the front side and the outer peripheral side of the main beam, the front sub-beam reflected light signal waveform obtained during recording is as shown in FIG.
The waveform is such that the recording pulse signal waveforms are simply superimposed.

On the other hand, since the rear sub-beam traces the rear and inner circumference sides of the main beam, the rear sub-beam reflected light signal waveform obtained during recording is as shown in FIG. 4B. Unlike the waveform, the signal level is lowered due to the influence of the recorded marks. The front sub-beam reflected light signal level and the rear sub-beam reflected light signal level are AD-converted by the voltage detection circuit 11 and can be acquired by the CPU 12. The amount of decrease in the signal level of the rear sub-beam reflected light depends on the shape of the recorded mark. For example, if the amount of decrease is small, the shape of the recorded mark is thin, and conversely, if the amount of decrease is large, the recorded mark is small. Will be thicker. If this rear sub-beam reflected light signal level is normalized by the front sub-beam reflected light signal level, the normalized value is
Depends on mark shape. Therefore, when the recording power is optimized according to the linear velocity, the value obtained by normalizing the rear sub-beam reflected light signal level by the front sub-beam reflected light signal level is the target value, specifically, the reflected light amount by the front sub-beam and the rear sub-beam. If the recording power is controlled so that the ratio of the amount of light reflected by the sub-beams reaches the target value,
A uniform mark is formed regardless of the linear velocity.

In the case of a recordable optical disc such as a CD-R, just before recording in the data area, trial writing is performed in the PCA area prepared in the innermost peripheral portion of the disc to determine the optimum recording power. At this time, at the same time, the optimum value of the value obtained by normalizing the rear sub-beam reflected light signal level by the front sub-beam reflected light signal level is acquired. When recording in the data area, the optimum value of the value obtained by normalizing the rear sub-beam reflected light signal level acquired in the PCA area in advance with the front sub-beam reflected light signal level is set as the target value.
Control the recording power.

The optimum value of the value obtained by normalizing the rear sub-beam reflected light signal level by the front sub-beam reflected light signal level is stored in the non-volatile memory 15 as the target value, and the value is timely stored in the non-volatile memory. The recording power is read out from 15, and the recording power is controlled by the CPU 12 as described above with the target value.

Further, the CPU 12 is constructed as follows. The amount of reflected light of the front sub-beam and the amount of reflected light of the rear sub-beam received by the light receiving element 9 are affected by the light receiving sensitivity of the light receiving element 9. To compensate for that effect,
The CPU 12 previously acquires the relationship between the front sub-beam reflected light signal level and the rear sub-beam reflected light signal level in the unrecorded area of the optical disc 1, and derives the correction coefficient from the relationship. When the rear sub-beam reflected light signal level is normalized by the front sub-beam reflected light signal level, it is possible to remove the influence of fluctuations in the light receiving sensitivity due to the operating environment and deterioration of the light receiving element 9 by multiplying the acquired correction coefficient. it can.

The present invention is not limited to recording at a constant rotational speed,
It can also be applied to the case where an optical disc is divided into a plurality of areas having different linear velocities and recorded.
Each of the embodiments is not limited to CD-R, and can be applied to an optical disc having a recording power linear velocity dependency.

In each of the above embodiments, the target value is described as being constant regardless of the recording position on the optical disk. However, depending on the recording position, specifically, the target value on the inner circumference side and the outer circumference side is the same. It is also possible to control the corrected value as the target during the recording power control, and the target value includes the corrected value.

[0041]

As described above, according to the optical disc apparatus of the present invention, when recording is performed on an optical disc having a linear velocity dependence of the recording power while changing the linear velocity, the state of the mark recorded during recording is detected. However, since the recording power can be optimized according to each linear velocity, the recording state of the optical disc can be made uniform regardless of the linear velocity.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an optical disk device according to (Embodiment 1) or (Embodiment 3) of the present invention.

FIG. 2 is an RF signal waveform and recording pulse waveform diagram in the same (Embodiment 1).

FIG. 3 is a layout diagram of a front sub-beam and a rear sub-beam according to (Embodiment 3) of the present invention.

FIG. 4 is a waveform diagram of a front sub-beam reflected light signal and a rear sub-beam reflected light signal waveform in the same (Embodiment 3).

[Explanation of symbols]

1 optical disc 2 optical pickup 3 Laser diode 4 laser driver 5 diffraction grating 6 Beam splitter 7 Objective lens 8 Power detection circuit 9 Light receiving element 10 Light receiving signal processing circuit 11 Voltage detection circuit 12 Microcomputer (CPU) 13 Encoder / Decoder 14 Voltage generation circuit 15 Non-volatile memory

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5D090 AA01 BB03 CC01 CC18 DD03                       EE03 FF36 FF50 KK03                 5D119 AA23 BA01 BB02 DA01 HA45                 5D789 AA23 BA01 BB02 DA01 HA45

Claims (8)

[Claims] 1. An optical disc is rotated at an arbitrary linear velocity to irradiate the optical disc with an arbitrary recording power,
In an optical disc device including an optical pickup that receives reflected light from the optical disc, first means for obtaining a peak value and a bottom value of a reflected light amount in a recording power irradiation section of the optical disc having a linear velocity dependence of the recording power, An optical disc apparatus comprising: second means for controlling the recording power output from the optical pickup so that a value obtained by normalizing the bottom value with a peak value becomes a target value. 2. An optical disc is rotated at an arbitrary linear velocity to irradiate the optical disc with an arbitrary recording power,
In an optical disc device including an optical pickup that receives reflected light from the optical disc, a bottom value of a reflected light amount in a recording power irradiation section of the optical disc having a linear velocity dependence of recording power and a recording power value irradiated on the optical disc are calculated. An optical disc provided with a first means for acquiring and a second means for controlling the recording power output from the optical pickup so that a value obtained by normalizing the bottom value with the recording power value becomes a target value. apparatus. 3. The optical disk apparatus according to claim 1, wherein the target value is acquired during an optimum recording power detection process executed before data recording on the optical disk. 4. The method according to claim 1, wherein the target value is stored in a memory, and the recording power is controlled by using the target value stored in the memory during recording. The optical disk device described. 5. An optical disk device provided with an optical pickup which rotates an optical disk at an arbitrary linear velocity, irradiates the main beam, front sub-beams and rear sub-beams on the optical disk, and receives reflected light from the optical disk. A first means for obtaining the amount of reflected light by the front sub-beam and the amount of reflected light by the rear sub-beam; and the light so that a value obtained by normalizing the rear sub-beam reflected light signal level by the front sub-beam reflected light signal level becomes a target value. An optical disc device provided with a second means for controlling the recording power output from a pickup. 6. The optical disk device according to claim 5, wherein the target value is acquired during an optimum recording power detection process executed before data recording on the optical disk. 7. The optical disk device according to claim 5, wherein the target value is stored in a memory, and the recording power is controlled by using the target value stored in the memory during recording. . 8. A light receiving sensitivity difference between the amount of reflected light by the front sub-beam and the amount of reflected light by the rear sub-beam is acquired,
6. A structure configured to correct the ratio of the reflected light amount of both.
The optical disk device described.