JP2004005984A - Optical disk drive - Google Patents

Abstract

For example, the recording speed of an optical disk of a constant linear density system such as a CD-R is improved, and control for obtaining an optimum recording laser power according to a change in the linear speed during recording is enabled.
An optical disk drive for irradiating a track on a disk with a laser beam and recording / reproducing information at a substantially constant linear density, rotates the disk at a predetermined number of revolutions at the time of recording information, and uses the recording laser power. Recording control means is provided for detecting the amount of reflected light from the disk when irradiating the laser beam and controlling the recording laser power in accordance with the detected reflected light amount.
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk drive, and more particularly, to a recording laser power control device and a spindle motor control device in an optical disk (CD-R, CD-E, etc.) drive of a constant linear density system.
[0002]
[Prior art]
An optical disk drive that irradiates a track on a disk with a laser beam and records / reproduces information at a substantially constant linear density is used for driving an optical disk such as a CD-R or a CD-E.
In this case, an apparatus has been proposed in which the linear density is controlled to be substantially constant by changing the recording / reproducing clock in accordance with the track radius while the disk rotation speed is kept substantially constant (Japanese Patent Laid-Open No. Hei. 126472, JP-A-2-183469, etc.).
Prior to recording of information, a predetermined number of recordings are performed on a track at a predetermined radial position on the disk with a different recording laser power for each step, and the recording position is reproduced to detect a characteristic value relating to a reproduction signal. An apparatus employing a laser power calibration method for determining an optimum recording laser power from a detection characteristic value, that is, an OPC (Optimum Power Calibration) in a CD-R is already known (Japanese Patent Laid-Open No. 7-85494).
Further, at the time of recording information, a control method of detecting a reflected light amount from a disk when a laser beam is irradiated with a recording laser power and controlling the recording laser power according to the detected reflected light amount, that is, a so-called ROPC (Running) in a CD-R. Optimum Power Calibration is also conventionally known (JP-A-4-10237).
[0003]
[Problems to be solved by the invention]
As described in the prior art, various control methods and devices have already been proposed for an optical disk drive that irradiates a track on a disk with a laser beam and records / reproduces information at a substantially constant linear density. ing.
Here, the problem of the conventional technique will be described.
For example, in a digital disk called a compact disk (CD), spiral tracks are formed on the disk at a constant linear density from the inner circumference to the outer circumference.
Further, a CD on which information can be recorded is also known as a CD-R (CD Recordable) (for example, Japanese Patent Application Laid-Open No. 7-85494 described above), and when information is recorded on a CD-R, When formed in a spiral shape from the inner periphery to the outer periphery, it is necessary to record information on the rack so as to have a constant linear density.
[0004]
FIG. 7 shows a track radius R, a disk rotation speed N, and a recording / reproducing data transfer rate F when a constant linear density optical disk such as a CD-R is rotated at a constant linear velocity (CLV method). It is a figure which shows an example of the relationship of.
[0005]
FIG. 8 shows a track radius R, a disk rotation speed N, and a recording / reproducing data transfer rate F when the optical disk of a constant linear density system such as a CD-R is rotated at a constant rotation speed (CAV system). It is a figure which shows an example of the relationship of.
[0006]
7 and 8, the CAV (Constant Angular Velocity) system, that is, the constant rotation speed system is different from the CLV (Constant Linear Velocity) system, that is, the constant linear velocity system. There are two advantages:
First, since the data transfer rate increases with an increase in the track radius, the recording speed can be improved.
In addition, since the disk rotation speed does not change, a small motor with a small torque can be used.
However, the CAV system also has the following problems.
In the case of the CAV method, the linear velocity increases with an increase in the track radius, but the optimum recording laser power varies depending on the linear velocity. You can't get it.
This relationship will be described for a radial format of a CD-R disc.
[0007]
FIG. 9 is a diagram showing an example of a radial format of a CD-R disc.
[0008]
In the disc shown in FIG. 9, a PCA (Power Calibration Area) in the inner peripheral area performs recording a predetermined number of times with different recording laser powers of several steps before recording information, and reproduces and reproduces the recording position. This is an area for performing so-called OPC (Optimum Power Calibration) for detecting a characteristic value related to a signal and determining an optimum recording laser power based on the detected characteristic value.
Since this PCA is located at the inner radius of the disc, even if information is recorded while maintaining the optimum recording laser power obtained here in the CAV method, optimum information recording will not be achieved.
In summary, the CAV method (constant rotation speed method) first increases the data transfer rate with an increase in the track radius, as compared with the CLV method (constant linear velocity method). There is an advantage that it can be improved, and secondly, it is possible to use a small motor with a small torque because the disk rotation speed does not change, but on the other hand, the PCA of the inner peripheral area of the disk is reduced. There is a problem that even if the optimum recording laser power is determined by using the information, the optimum information recording cannot be performed due to a change in the recording position.
According to the present invention, in an optical disk drive that irradiates a track on a disk with a laser beam to record / reproduce information at a substantially constant linear density, the recording speed of an optical disk of a constant linear density system such as a CD-R is improved. It is another object of the present invention to obtain an optimum recording laser power according to a change in linear velocity during recording.
[0009]
[Means for Solving the Problems]
In the invention of claim 1,
In an optical disk drive that irradiates a track on a disk with a laser beam and records / reproduces information at a substantially constant linear density, when recording information, the disk is rotated at a predetermined number of revolutions, and the laser beam is radiated at a recording laser power. A recording control means for detecting the amount of reflected light from the disk when the recording is performed and controlling the recording laser power in accordance with the detected reflected light amount is provided.
[0010]
In the invention of claim 2,
2. The optical disk drive according to claim 1, wherein the recording control means includes means for rotating the disk at a predetermined rotation speed in a recording track area where the recording laser power is equal to or less than a predetermined upper limit value when recording information, and the recording laser power is set to a predetermined upper limit. In the recording track area after reaching the value, a means for rotating the disk at a constant linear velocity is provided.
[0011]
In the invention of claim 3,
2. The optical disk drive according to claim 1, wherein, when recording information, the recording control means increases a disk linear velocity when the recording laser power is lower than a predetermined value, and increases a disk speed when the recording laser power exceeds the predetermined value. Means for reducing the linear velocity are provided.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the optical disk drive of the present invention will be described in detail with reference to the drawings. First, reference technology of the present invention will be described.
First reference technology
The first reference technique is characterized in that correction is performed according to a change in linear velocity due to a CAV operation based on an optimum recording power determined by OPC, and information is recorded with the corrected recording power. I have.
[0013]
FIG. 1 is a functional block diagram showing an example of a main configuration of the optical disk drive of the first reference technology. In the figure, 1 is an optical disk, 2 is an optical pickup, 3 is an LD power control circuit, 4 is an encoder, 5 is a reproducing amplifier, 6 is a slicer, 7 is a decoder, 8 is a peak hold circuit, 9 is a bottom hold circuit, and 10 is An A / D converter, 11 is a controller, 12 is a rotation control circuit, 13 is a spindle motor, Sw is a wobble signal, and Sr is a reproduction signal.
[0014]
First, the general configuration and operation will be described.
Tracks are formed on the optical disc 1 in a spiral shape from the inner circumference to the outer circumference.
As described with reference to FIG. 9, the radial format of the optical disc 1 is provided in the inner peripheral area of the disc as an area where the PCA performs OPC for determining an optimum recording laser power prior to recording of information. ing.
The tracks of the optical disk 1 are formed by pregrooves, and the pregrooves wobble slightly in the radial direction at a center frequency of 22.05 KHz (when the disk is rotated at the reference linear velocity).
[0015]
The optical pickup 2 includes a light source for irradiating a track on the optical disc 1 with a laser beam.
The reflection signal from the optical disk 1 is amplified by the reproduction amplifier 5.
The reproduction amplifier 5 outputs a reproduction signal Sr corresponding to the information recorded on the track and a wobble signal Sw corresponding to the wobbling of the pre-groove from the reflection signal.
During the CLV operation, the rotation control circuit 12 controls the spindle motor 13 according to the linear velocity setting from the controller 11 so that the wobble signal Sw has a predetermined frequency so that a constant linear velocity is obtained.
In addition, during the CAV operation, the spindle motor 13 is controlled according to the rotation speed setting from the controller 11 so that a constant rotation speed is obtained.
[0016]
During reproduction, the LD power control circuit 3 controls the power of the laser beam to be the reproduction laser power.
At the time of recording, the power of the laser beam is modulated into two levels of a recording laser power and a reproduction laser power in accordance with the recording codes “1” and “0” output from the encoder 4.
The recording laser power can be changed according to the setting from the controller 11.
The peak hold circuit 8 and the bottom hold circuit 9 detect the peak level and the bottom level of the envelope of the reproduction signal Sr during reproduction, respectively.
The detected peak level and bottom level are A / D converted by the A / D converter 10, so that the controller 11 can read the converted D (digital) data.
The above is the general configuration and operation.
[0017]
Next, the operation at the time of executing the OPC will be described.
In the optical disk drive of the first reference technique, test recording is first performed on the PCA unit on the optical disk 1 when OPC is performed.
At the time of test recording, the controller 11 performs recording for a predetermined block (for example, 15 blocks) while increasing the recording laser power for each block.
Next, the optical disk drive reproduces the test recording section.
[0018]
FIG. 2 is a characteristic diagram for explaining the operation during test recording and during reproduction. (1) shows the relationship between the recording block and the recording laser power during test recording, and (2) shows the reproduction block and the peak level P during reproduction. FIG. 4 is a diagram illustrating a relationship between bottom levels B and Beta. In the figure, the horizontal axis indicates the block number, the vertical axis of (1) indicates the recording laser power, and the vertical axis of (2) indicates the detected level.
[0019]
During test recording, as shown in FIG. 2A, data is recorded in a plurality of recording blocks while gradually changing the recording laser power.
When this test recording section is reproduced, peak level P and bottom level B data are obtained from the reproduced block as shown in FIG. 2 (2).
For this purpose, the controller 11 reads the peak level P and the bottom level B that have been A / D converted for each block.
After reading the peak level P and the bottom level B of all the blocks, the controller 11 performs an operation according to the equation Beta = (P + B) / (P−B), and the Beta value is a predetermined value (for example, 0.04). Is determined as the optimum recording laser power.
When performing OPC, the optical disk drive performs a CLV operation.
[0020]
Next, the operation at the time of actual information recording will be described.
The optical disk drive performs a CAV operation when recording information.
The relationship between the recording track radius (R) during the CAV operation and the recording data transfer rate (F) is as shown in FIG.
In the CAV operation, in order to record information at a constant linear density, it is necessary to change a recording data transfer rate in proportion to a change in linear velocity.
Therefore, in this optical disk drive, the encoder 4 changes the recording data transfer rate in proportion to the frequency of the wobble signal.
Since the frequency of the wobble signal Sw is proportional to the linear velocity, recording at a constant linear density can be performed.
Here, the recording data transfer clock generation circuit will be described.
[0021]
FIG. 3 shows an example of a recording data transfer clock generation circuit provided inside the encoder 4. In the figure, 21 indicates a phase comparator, 22 indicates a low-pass filter, 23 indicates a VCO, 24 indicates a frequency divider, Sw indicates a wobble signal, and CLK indicates a recording data transfer clock.
[0022]
The recording data transfer clock CLK is generated by a VCO (Voltage Controlled Oscillator) 23.
The generated recording data transfer clock CLK is frequency-divided by 196 by the frequency divider 24 and fed back to the phase comparator 21.
The phase comparator 21 compares the phase of the wobble signal Sw with the frequency-divided clock fed back and outputs a phase difference signal.
The phase difference signal is smoothed by the low-pass filter 22 and input to the VCO 23.
Since the circuit of FIG. 3 is a PLL (Phase Locked Loop), the frequency of the recording data transfer clock CLK is maintained at 196 times the frequency of the wobble signal Sw.
When the linear velocity is k times the reference value, the frequency of the wobble signal Sw is k * 22.05 KHz, and the recording data transfer clock frequency is k * 22.05 KHz * 196 = k. * 4.3218 MHz, and a frequency proportional to the linear velocity can be obtained.
[0023]
In the optical disk drive of the first reference technique, at the time of recording, the controller 11 converts the recording laser power obtained by correcting the optimum recording laser power determined by the OPC according to the frequency of the wobble signal Sw into an LD power control circuit. Set to 3.
Next, the correction operation of the recording laser power by the controller 11 will be described.
As described above, the frequency of the wobble signal Sw is proportional to the linear velocity.
The controller 11 has a ROM or the like in which a conversion table between a predetermined frequency of the wobble signal Sw and a correction coefficient m is stored.
[0024]
FIG. 4 is a diagram illustrating an example of a graph-like content of a conversion table between the frequency of the wobble signal Sw and the correction coefficient m. The horizontal axis of the figure shows the frequency of the wobble signal Sw, and the vertical axis shows the correction coefficient m.
[0025]
During the recording operation, the controller 11 measures the wobble signal frequency, for example, once per second.
Then, every time the wobble signal frequency is measured, the correction coefficient m is obtained by referring to the conversion table as shown in FIG.
Thereafter, the optimum recording laser power determined by OPC is multiplied by a correction coefficient m to obtain a recording laser power.
[0026]
In this case, the correction coefficient m in the conversion table is determined so as to represent the optimum correction coefficient for each linear velocity.
For this reason, according to the optical disk drive device according to the first reference technology, a correction according to a linear velocity change due to the CAV operation is performed based on the optimum recording power determined by the OPC. Information recording will be performed.
Therefore, for example, the recording speed of an optical disc of a constant linear density type such as a CD-R can be improved, and the optimum recording laser power can be set according to the change in the linear velocity during recording.
[0027]
Second reference technology
In the first reference technique described above, a case has been described in which, based on the optimum recording power determined by the OPC, a correction is performed according to a change in linear velocity due to the CAV operation, and information is recorded using the corrected recording power.
That is, in the first reference technique, the CAV operation is always performed during information recording.
Therefore, the correction coefficient m gradually increases as the linear velocity increases as the recording position moves to the outer peripheral position of the disk.
As a result, when the recording sensitivity of the disk is low and the optimum recording power determined by the OPC is large, there is a possibility that the recording power at the outer peripheral position of the disk may exceed the maximum output of the laser.
[0028]
In the second reference technique, correction is performed in accordance with a change in linear velocity due to CAV operation based on the optimum recording power determined by OPC. It is characterized in that information is recorded by the CLV operation with a recording laser power equal to the maximum output of the laser.
The hardware configuration of the second reference technique is the same as that of FIG.
Also in the second reference technique, when the recording laser power is equal to or less than the maximum output of the laser at the time of recording, the device operates in the same manner as the device according to the first reference technique.
However, when the recording position moves to the outer periphery of the disk and the recording power obtained by multiplying the optimum recording power determined by the OPC by the correction coefficient m reaches the maximum output of the laser, the recording power is maintained at the recording position after that point. While switching to the CLV operation.
More specifically, the operation of the controller 11 is to compare the obtained recording laser power with a predetermined maximum output of the laser in addition to the operation of obtaining the recording laser power described in the first reference technology. Operation is added.
Then, as a result of the comparison, after the recording laser power exceeds the maximum output of the laser, the recording laser power set in the LD power control circuit 3 is set to the maximum output.
Further, the mode of the rotation control circuit 12 is switched to the CLV operation.
The set value of the linear velocity for the CLV operation is the linear velocity value at that time.
[0029]
As described above, according to the optical disk drive device according to the second reference technology, the correction according to the linear velocity change by the CAV operation is performed based on the optimum recording power determined by the OPC, and the corrected recording power In addition, information is recorded, and in the recording area after the corrected recording laser power reaches the maximum output of the laser, the information recording by the CLV operation is performed by the recording laser power equal to the maximum output of the laser.
Therefore, good recording is possible even when a disk with low recording sensitivity or an optical pickup with low maximum laser output is used.
[0030]
Next, an embodiment of the present invention will be described.
First embodiment
This first embodiment corresponds to the first aspect of the present invention.
In the first embodiment, even if the linear velocity changes due to the CAV operation, an appropriate pit is formed based on the signal level corresponding to the amount of reflected light from the disk when the laser beam is irradiated with the recording laser power. The feature is that the information recording is always performed with the optimum recording laser power by controlling the recording laser power so that it is formed.
[0031]
FIG. 5 is a functional block diagram showing an example of another embodiment of the main part configuration of the optical disk drive of the present invention. Reference numerals in the figure are the same as those in FIG.
[0032]
In the optical disk drive shown in FIG. 5, a sample hold circuit 14 and a timing circuit 15 are provided instead of the peak hold circuit 8 and the bottom hold circuit 9 shown in FIG.
The sample hold circuit 14 samples a signal level corresponding to the amount of reflected light from the optical disc 1 when a laser beam is irradiated with recording laser power during recording.
The timing circuit 15 generates a sampling signal at a timing necessary for the sampling.
Here, the relationship between the laser beam output and the amount of reflected light from the disk when the laser beam is irradiated with the recording laser power will be described.
When the optical disk 1 is irradiated with a laser beam at the recording laser power, a reflected light amount as shown in FIG.
[0033]
FIG. 6 is a time chart showing an example of the relationship between the laser beam output and the amount of reflected light from the disk when the disk is irradiated with the recording laser power, where (1) is the laser power, (2) is the amount of reflected light from the disk, (3) indicates the output of the timing circuit 15, and T1 and T2 indicate the timing.
[0034]
When a laser beam is irradiated by the recording laser power, the amount of reflected light from the disk initially becomes (recording laser power) * (reflectance of the disk in an unrecorded state) as shown at a timing T1 in FIG. It becomes a proportional value.
Thereafter, pits begin to be formed on the disk by the laser power at the recording level. Finally, as shown at timing T2 in FIG. 6B, (recording laser power) * (reflection of the disk at the pit forming portion) Ratio).
Therefore, as shown in FIG. 6 (2), the level of the reflected light amount from the disk at the timing T2 increases when the recording laser power is insufficient and the pits are insufficiently formed. Is excessive and pit formation is excessive, the level decreases.
Therefore, the sample and hold circuit 14 samples the level of the amount of light reflected from the disk at the timing T2 according to the sampling signal from the timing circuit 15.
Since the sampled reflected light level is A / D converted by the A / D converter 10, the controller 11 can read the converted digital data.
[0035]
In the first embodiment, the optical disk drive performs a CAV operation when recording information.
Further, the recording data transfer clock is similarly generated by the circuit of FIG. 3 described in the first reference technology.
At the time of recording the information, the controller 11 reads the A / D-converted reflected light amount level, and increases or decreases the recording laser power value set for the LD power control circuit 3 so that the reflected light amount level becomes a predetermined level. .
At this predetermined level, the amount of reflected light when recording is performed at the optimum recording power and an appropriate pit is formed is set in advance.
As described above, according to the optical disk drive device of the first embodiment, even if the linear velocity changes due to the CAV operation, it corresponds to the amount of reflected light from the disk when the laser beam is irradiated with the recording laser power. Since the recording laser power is controlled based on the signal level so that an appropriate pit is formed, information recording is always performed with the optimum recording laser power.
Therefore, information recording can always be performed with the optimum recording laser power even when there is unevenness in the sensitivity of the disk as well as a change in the linear velocity.
[0036]
Second embodiment
The second embodiment corresponds to the second aspect of the present invention.
In the first embodiment, when the linear velocity changes due to the CAV operation, an appropriate pit is determined based on the signal level corresponding to the amount of reflected light from the disk when the laser beam is irradiated with the recording laser power. The case in which the recording laser power is controlled so that is formed is described.
That is, in the first embodiment, the CAV operation is always performed during information recording.
Therefore, the correction coefficient m gradually increases as the linear velocity increases as the recording position moves to the outer peripheral position of the disk.
As a result, when the recording sensitivity of the disk is low, there is a possibility that the recording power at the outer peripheral position of the disk may exceed the maximum output of the laser.
[0037]
In the second embodiment, even if the linear velocity changes due to the CAV operation, an appropriate pit is formed based on the signal level corresponding to the amount of reflected light from the disk when the laser beam is irradiated with the recording laser power. The feature is that the information recording is always performed with the optimum recording laser power by controlling the recording laser power so that it is formed.
The hardware configuration of the second embodiment is the same as that of FIG.
Also in the second embodiment, when the recording laser power is equal to or less than the maximum output of the laser at the time of recording, the device operates in the same manner as the device according to the first embodiment.
However, when the recording position moves to the outer peripheral position of the disk and the recording power reaches the maximum output of the laser, the recording position after that point is switched to the CLV operation while maintaining the recording power.
Specifically, the operation of the controller 11 includes, in addition to the operation of obtaining the recording laser power described in the third embodiment, comparing the obtained recording laser power with the predetermined maximum output of the laser. Operation to be added.
Then, as a result of the comparison, after the recording laser power exceeds the maximum output of the laser, the recording laser power set in the LD power control circuit 3 is set to the maximum output of the laser.
Further, the mode of the rotation control circuit 12 is switched to the CLV operation.
The set value of the linear velocity for the CLV operation is the linear velocity value at that time.
Then, in the recording area after the recording power reaches the maximum output of the laser, information recording by the CLV operation is performed with the recording laser power equal to the maximum output of the laser.
[0038]
As described above, according to the optical disk driving device of the second embodiment, even if the linear velocity changes due to the CAV operation, it corresponds to the amount of reflected light from the disk when the laser beam is irradiated with the recording laser power. Since the recording laser power is controlled so that an appropriate pit is formed based on the signal level to be generated, information recording is always performed with the optimum recording laser power.
Therefore, it is possible to always perform information recording with the optimum recording laser power even when there is unevenness in the sensitivity of the disk as well as the change in the linear velocity.
In the recording area after the recording power reaches the maximum output of the laser, information recording is performed by the CLV operation with the recording laser power equal to the maximum output of the laser. Alternatively, an optical pickup having a low optical pickup can be used.
[0039]
Third embodiment
This third embodiment corresponds to the third aspect of the present invention.
In the third embodiment, the recording laser power is controlled so that an appropriate pit is formed based on a signal level corresponding to the amount of reflected light from the disk when the laser beam is irradiated with the recording laser power. Thus, information recording is always performed with an optimum recording laser power.
Also in the third embodiment, the hardware configuration is the same as that of FIG.
Also in the third embodiment, the optical disk drive performs the CLV operation at the time of recording information.
At the time of recording the information, the controller 11 reads the A / D-converted reflected light amount level, and increases or decreases the recording laser power value set for the LD power control circuit 3 so that the reflected light amount level becomes a predetermined level. .
At this predetermined level, the amount of reflected light when recording is performed at the optimum recording power and an appropriate pit is formed is set in advance.
Further, when the recording laser power value set by the above-described operation is smaller than the maximum output of the laser, the controller 11 increases the linear velocity value set in the rotation control circuit 12.
As the linear velocity increases, the required recording laser power value also increases.
The controller 11 increases the linear velocity value until the set recording laser power becomes equal to the maximum output of the laser.
Conversely, when the set recording laser power value is larger than the maximum output of the laser, the linear velocity value set in the rotation control circuit 12 is reduced.
[0040]
As described above, according to the optical disk drive of the third embodiment, an appropriate pit is formed based on the signal level corresponding to the amount of reflected light from the disk when the laser beam is irradiated with the recording laser power. The recording laser power is controlled so that
Therefore, information can always be recorded with the optimum recording laser power.
Further, the disk linear velocity is automatically increased until the set recording laser power becomes equal to the maximum output of the laser.
Therefore, according to the maximum output of the laser and the disk sensitivity, it is possible to set the disk linear velocity to always be the maximum, and the recording speed can be extremely increased.
[0041]
【The invention's effect】
According to the optical disk drive of the first aspect, even if the linear velocity changes due to the CAV operation, an appropriate pit is formed based on the signal level corresponding to the amount of reflected light from the disk when the laser beam is irradiated with the recording laser power. Since the recording laser power is controlled so as to be formed, information recording is always performed with the optimum recording laser power.
Therefore, information recording is always performed with the optimum recording laser power even when there is unevenness in the sensitivity of the disk as well as a change in the linear velocity.
[0042]
According to the optical disk drive device of the second aspect, even if the linear velocity changes due to the CAV operation, an appropriate pit is formed based on the signal level corresponding to the amount of reflected light from the disk when the laser beam is irradiated with the recording laser power. The recording laser power is controlled so as to be formed, and information recording is always performed with the optimum recording laser power.
Therefore, information recording is always performed with the optimum recording laser power even when there is unevenness in the sensitivity of the disk as well as a change in the linear velocity.
In the recording area after the recording power reaches the maximum output of the laser, information recording by the CLV operation is performed with the recording laser power equal to the maximum output of the laser.
As a result, a disk with low recording sensitivity and an optical pickup with a low maximum laser output can be used.
[0043]
In the optical disk drive of claim 3, the recording laser power for forming an appropriate pit is controlled based on a signal level corresponding to the amount of reflected light from the disk when the laser beam is irradiated with the recording laser power, Information recording is always performed with the optimum recording laser power.
Therefore, information recording is always performed with the optimum recording laser power even when there is unevenness in the sensitivity of the disk as well as a change in the linear velocity.
Further, the disk linear velocity is automatically increased until the set recording laser power becomes equal to the maximum output of the laser.
As a result, it is possible to always set the disk linear velocity to the maximum according to the maximum output of the laser and the disk sensitivity, and it is possible to extremely increase the recording speed.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing an example of a main configuration of an optical disk drive according to a reference technique of the present invention.
FIG. 2 is a characteristic diagram illustrating operations during test recording and reproduction.
FIG. 3 shows an example of a recording data transfer clock generation circuit provided inside an encoder 4.
FIG. 4 is a diagram showing an example of a graph-like content of a conversion table between a frequency of a wobble signal Sw and a correction coefficient m.
FIG. 5 is a functional block diagram showing an example of an embodiment of a main part configuration of the optical disk drive of the present invention.
FIG. 6 is a time chart showing an example of a relationship between a laser beam output when a disk is irradiated with a recording laser power and an amount of reflected light from the disk.
FIG. 7 shows a case where an optical disk of a constant linear density such as a CD-R is rotated at a constant linear velocity (CLV method), a track radius R on the disk, a disk rotation speed N, and a recording / reproducing data transfer rate F. It is a figure which shows an example of the relationship of.
FIG. 8 shows a track radius R, a disk rotation speed N, and a recording / reproducing data transfer rate F when an optical disk such as a CD-R or the like having a constant linear density is rotated at a constant rotation speed (CAV system). It is a figure which shows an example of the relationship of.
FIG. 9 is a diagram showing an example of a radial format of a CD-R disc.
[Explanation of symbols]
1 optical disk
2 Optical pickup
3 LD power control circuit
4 Encoder
5 playback amplifier
6 Slicer
7 Decoder
8 Peak hold circuit
9 Bottom hold circuit
10 A / D converter
11 Controller
12 Rotation control circuit
13 Spindle motor
14 Sample hold circuit
15 Timing circuit
21 Phase comparator
22 Low-pass filter
23 VCO
24 divider

Claims (3)

In an optical disk drive that irradiates a laser beam onto a track on a disk and records / reproduces information at a substantially constant linear density,
At the time of recording information, the disc is rotated at a predetermined number of revolutions, a recording control means for detecting the amount of reflected light from the disc when irradiating the laser beam with the recording laser power, and controlling the recording laser power according to the detected reflected light quantity. An optical disk drive, comprising: an optical disk drive; The recording control means includes: rotating a disk at a predetermined rotation speed in a recording track area where the recording laser power is equal to or lower than a predetermined upper limit; 2. The optical disk drive according to claim 1, further comprising means for rotating the optical disk at a constant linear velocity. The recording control means includes means for increasing a disk linear velocity when the recording laser power is lower than a predetermined value, and decreasing the disk linear velocity when the recording laser power is higher than a predetermined value. The optical disk drive according to claim 1, wherein

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