JP2874643B2 - Optical disk drive method and optical disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical disk drive method and an optical disk drive for an optical disk drive used as an external storage device of a computer for recording and reproducing data.

[0002]

2. Description of the Related Art An optical disc has a feature that a large amount of data can be recorded and reproduced at a high speed. Optical disks are rapidly spreading as central storage media for multimedia systems. The characteristics of an optical disk such as a CD-ROM as a storage medium are also used in a small and lightweight notebook computer. As a result, efforts have been made to reduce the size and thickness of the optical disk drive for driving the optical disk and to reduce power consumption. Hereinafter, a conventional optical disk drive will be described using a CD-ROM drive as an example.

FIG. 7 is a block diagram of a conventional optical disk drive. In the figure, the conventional optical disk device is configured as follows. That is, reference numeral 1 denotes an optical disk on which information is recorded as a row of optical pits. Reference numeral 2 denotes a spindle motor that drives the optical disk 1 to rotate. Reference numeral 3 denotes an optical pickup, which is an optical system for focusing the emitted laser light on the optical disc 1 and imaging the reflected light on the sensor, and the above-described sensor for converting the reflected light to an electric signal.
A drive system for moving the optical disc 1 in the radial direction and the normal direction is integrally formed. Reference numeral 4 denotes a servo controller, which controls the optical pickup 3 so as to follow a row of optical pits on the optical disk 1. Reference numeral 5 denotes a reproduction signal detector, which binarizes an electric signal obtained from a sensor of the optical pickup 3. 6 is a synchronous clock generator,
A synchronous clock synchronized with the reproduction signal from the reproduction signal detector 5 is generated. Reference numeral 7 denotes a rotation controller which controls the optical disc 1
(That is, the spindle motor 2) is controlled to a predetermined rotation speed. Reference numeral 8 denotes a spindle driver, which drives the spindle motor 2 according to a control signal of the rotation controller 7. Reference numeral 9 denotes a signal processor, which reproduces data based on the reproduction signal and the synchronous clock, and controls the operation of the entire optical disk drive.

The operation of the conventional optical disk drive configured as described above will be described. The information signal of the optical pit train recorded on the optical disc 1 is read by the optical pickup 3, and the servo controller 4 causes the optical pickup 3 to follow the optical pit train of the optical disc 1. And the reproduction signal detector 5
The signal is detected and binarized. The synchronous clock generator 6 generates a synchronous clock synchronized with the binarized reproduction signal.

Next, the internal configuration and operation of the synchronous clock generator 6 will be described. Reference numeral 11 denotes a phase comparator, which compares the phase of the above-mentioned binarized reproduction signal with the output of a voltage controlled oscillator (VCO) 10 and outputs a phase difference signal. Reference numeral 12 denotes a loop filter that removes noise in a high frequency region of the phase difference signal and determines the response characteristics of the entire synchronous clock generator 6. Reference numeral 10 denotes a VCO that outputs a clock signal having an oscillation frequency according to the output voltage of the loop filter 12. This series of closed loop circuit configurations
In general, a circuit called a PLL (Phase Locked Loop) (hereinafter abbreviated as a PLL circuit) is configured. If the reproduction signal is within the synchronization pull-in range of the PLL circuit, a reproduction synchronization clock is generated.

On the other hand, a maximum time width detector 13 detects the maximum time width of the bit pattern of the reproduced signal. If the reproduced signal is out of the synchronization pull-in range of the PLL circuit, the maximum time width detector 13 outputs the maximum time width (CD-RO).
M, 11 channel clock length) is detected and VCO 10
And the error signal voltage corresponding to the count is input to the VCO 10 to change the oscillation frequency of the output of the VCO 10 so that the count of the maximum time width becomes 11 times.

As described above, the synchronous clock generator 6
Is controlled by the maximum time width detector 13 to fall within the synchronization pull-in range outside the synchronization pull-in range of the PLL circuit even when the rotation speed of the optical disk 1 does not reach the target rotation speed. As a result, the PLL circuit pulls in the synchronization and generates a synchronization clock of the reproduction signal. Thus, even when the rotation speed of the optical disc 1 is not at the target rotation speed, data can be reproduced based on the synchronization clock.

Next, the internal configuration of the rotation controller 7 and its operation will be described. First, a data string is recorded on the optical disc 1 for each block called a frame. Two patterns having a maximum time width called a frame synchronization signal are continuously recorded at the head of the frame.
The frame detector 14 detects a frame synchronization signal from the reproduction signal by using the above-mentioned synchronization clock.

However, there is a possibility that a detection error or an erroneous detection of the frame synchronization signal may occur due to the influence of dropout or jitter. Therefore, it is necessary to protect and interpolate the frame synchronization signal. Therefore, the phase difference between the frame synchronization signal and the output from the reference oscillator 15 is detected by the phase comparator 16, and the spindle motor 2 is controlled so that the period of the frame synchronization signal becomes constant. As a result, the optical pickup 3
The rotation controller 7 controls the rotation number to continuously change according to the reproduction position of the optical disc 1 even if the reproduction position changes due to the movement of the optical disk 1. Therefore, the linear velocity of the optical disk 1 is always controlled precisely.

[0010]

However, in the above-mentioned conventional configuration, the spindle motor is constantly driven so that the optical disk rotates at a constant linear velocity. For this reason,
There are problems such as an increase in power consumption of the optical disk drive and a limitation in miniaturization of the optical disk drive. In particular, when the optical disk drive is incorporated in a portable device such as a notebook computer, it has been an obstacle to reducing power consumption.

An object of the present invention is to solve the above-mentioned conventional problems and to provide an optical disk drive method and an optical disk drive device with low power consumption.

[0012]

In order to achieve the above-mentioned object, an optical disk drive according to the present invention comprises a reproduction signal
Synchronization that generates a synchronization clock to reproduce data from
Clock generation means and the frequency of the reproduced signal is synchronized clock
And the synchronization range required from the operating margin of each means
Within the synchronization tolerance set in the narrow range
A synchronous state determining means for outputting a command signal
Based on the signal, if it is within the synchronization tolerance range, it is driven to rotate
Stop driving of means and rotate by inertia, out of synchronization allowable range
Rotation drive control means for driving the rotation drive means if
And characterized in that:

With the above arrangement, when data is reproduced from the optical disk, if the frequency of the reproduction signal is within the synchronization range, the spindle motor is stopped and rotated by inertia. Can be driven.

Therefore, it is possible to greatly reduce power consumption by intermittently driving the spindle motor.
Immediately after receiving a data read command.
It is possible to provide an optical disk drive method and an optical disk drive device that can start the operation .

[0015]

The invention according to claim 1 of the embodiment of the present invention is an optical disk irradiates a laser beam to the optical disk
Information on the optical disk by following the recorded information pits
Information reading step to take and playback from the read information
A reproduction step of reproducing a signal;
A rotational driving step for rotationally driving the number of rotations.
Disk drive method for reproducing data from a reproduction signal
Clock generation step to generate a synchronization clock for
And the frequency of the playback signal
A range slightly smaller than the synchronization range required from the operating margin
Judge whether it is within the synchronization tolerance specified in the box.
Command signal output synchronization signal judgment step and command signal
Stops rotational drive if it is within the synchronization tolerance range
And rotate by inertia.
And a rotation drive control step of driving.
Optical disk driving method.

As described above, power consumption can be greatly reduced by intermittently driving the spindle motor.
At the same time, the data
An optical disk driving method capable of starting reading can be provided.

[0017]

[0018]

According to a second aspect of the present invention, the optical disk is irradiated with a laser beam and the reflected light is applied to an electric disk.
Optical unit for converting to signal and radial direction of optical disc
And the optical unit in the direction perpendicular to the recording surface of the optical disk
A pickup unit comprising a drive unit to be driven;
Playback signal from signal obtained from pickup unit
A reproduction signal detecting means for outputting the laser light,
Drives optical unit to focus on a given position
Servo control means for rotating the optical disc to a predetermined number of revolutions.
Rotational drive means for rotationally driving and controlling, and the entire optical disk device
Disk drive device having signal processing means for controlling the optical disk
Synchronization for reproducing data from the reproduction signal.
Synchronous clock generating means for generating a clock, and a reproduction signal
Is determined from the synchronous clock and the operation margin of each means.
Slightly smaller than the synchronization range
Judge whether it is within the allowable synchronization range and output the command signal
Synchronization state judgment means and synchronization permission based on the command signal
If it is within the range, stop the drive of the rotation drive means and
And if it is out of the synchronization allowable range, the rotation drive means
And rotation drive control means for driving the
Optical disk drive.

As described above, the spindle motor is intermittently
Driving can drastically reduce power consumption
At the same time, the data
An optical disk drive that can start reading
Can be provided. In particular, the drive content is
Peak value or drive time according to the speed of the pindle motor
Or change both of them, so a more fine-grained drive
Dynamic control, which can greatly reduce power consumption.
Wear.

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an optical disk drive according to a first embodiment of the present invention. In the figure, an optical disk 1, a spindle motor 2, an optical pickup 3, a servo controller 4, a reproduction signal detector 5, a synchronous clock generator 6, a spindle driver 8, and a signal processor 9 are the same as those of the conventional optical disk drive. , The same reference numerals are given, and the description will not be repeated.

Reference numeral 17 denotes a synchronization state determiner.
It determines whether or not the frequency of the reproduction signal is within a synchronization allowable range that is slightly narrower than the synchronization range including the operation margin of the synchronous clock generator 6 and the entire PLL circuit, and outputs a command signal. Reference numeral 18a denotes a spindle controller, which is within a synchronization allowable range by a command signal.
Stop driving the spindle motor 2 and rotate it by inertia.
If it is out of the synchronization allowable range, the spindle motor 2 is rotated so that the rotation speed of the spindle motor 2 falls within the synchronization allowable range.
Drive.

The operation of the optical disk driving device according to the first embodiment having the above-described configuration will be described. The information of the optical pit train recorded on the optical disk 1 is read by the optical pickup 3, and the servo controller 4
Is controlled so as to follow the optical pit row of the optical disc 1. The read recorded information is detected by the reproduced signal detector 5 and binarized.

The synchronous clock generator 6 generates a synchronous clock synchronized with the binarized reproduction signal. The synchronous clock generator 6 includes a PLL circuit (phase comparator 11, loop filter 12, VCO 10) and a maximum time width detector 13, and generates a synchronous clock for reproduction within the pull-in range of the PLL circuit. . Outside the synchronization pull-in range, the maximum time width detector 13 controls so as to fall within the synchronization pull-in range of the PLL circuit. And furthermore,
When the PLL circuit pulls in the synchronization, a synchronization clock of the reproduction signal is generated.

Next, the synchronization state determiner 17 measures the maximum time width of the reproduced signal detected by the maximum time width detector 13, and determines whether the frequency of the reproduced signal is within the allowable synchronization range based on the measurement result. Judgment is made, and the frequency of the reproduction signal is compared with a set value set by the signal processor 9.

FIG. 2 is a diagram showing the relationship between the command signal S1 and the spindle control signal S2. For example, as shown in FIG. 2, the synchronization state determiner 17 outputs the command signal S1 of “1” when the frequency of the reproduction signal is within the synchronization allowable range and when the frequency of the reproduction signal is smaller than the set value, and conversely. When the frequency of the reproduction signal is out of the allowable synchronization range and when the frequency is larger than the set value, the output of the command signal S1 is "0".

In response to the command signal S1, the spindle controller 18a sets the spindle control signal S2 to "OFF" when the command signal S1 is "1" and changes the spindle control signal S2 to "OFF" when the command signal S1 is "0". ON ”. That is, when the rotation speed of the optical disc 1 is within the range specified by the signal processor 9 and within the allowable synchronization range, the spindle motor 2 is turned off to rotate by inertia. If the value exceeds the value designated by 9 or is out of the synchronization allowable range, the drive of the spindle motor 2 is turned on and the rotation drive control is performed until a predetermined number of revolutions is reached.

As described above, according to the first embodiment of the present invention, the spindle motor 2 can be driven intermittently, so that the power consumption can be greatly reduced.

(Embodiment 2) Next, a second embodiment of the present invention will be described. FIG. 3 is a configuration diagram of an optical disk drive according to a second embodiment of the present invention. In the figure, an optical disk 1, a spindle motor 2, an optical pickup 3,
The servo controller 4, the reproduced signal detector 5, the synchronous clock generator 6, the spindle driver 8, and the signal processor 9 are the same components as those of the conventional optical disk drive, and the synchronous state determiner 17 is the first component. Since the components are the same as those of the optical disk drive in the embodiment, the same reference numerals are given and the description will not be repeated.

The following four elements are added. That is, reference numeral 18b denotes a spindle controller, which stops the drive of the spindle motor 2 and rotates by inertia when it is within the synchronization allowable range according to the command signal S1, and when it is out of the synchronization allowable range, the current rotational speed. And changes the peak value and the drive time of the drive output given to the spindle motor 2 in accordance with the above, and drives the spindle motor 2 so that the rotation speed of the spindle motor 2 falls within the allowable synchronization range. An encoder 19 generates an analog rotation signal according to the rotation of the spindle motor 2. A waveform shaper 20 binarizes the analog rotation signal. Reference numeral 21 denotes a rotation number detector which detects the rotation number of the spindle motor 2 from the binarized rotation signal.

The operation of the optical disk drive according to the second embodiment having the above-described configuration will be described. First
As in the case of the embodiment, the information on the optical disk 1 is read by the optical pickup 3, and the servo controller 4 causes the optical pickup 3 to follow the optical pit row. Then, the read record information is binarized by the reproduction signal detector 5, and a synchronization clock synchronized with the reproduction signal is generated by the synchronization clock generator 6.

As in the first embodiment, the synchronous clock generator 6
Generates a synchronous clock for reproduction within the pull-in range of the PLL circuit, and is controlled by the maximum time width detector 13 to fall within the pull-in range of the PLL circuit outside the pull-in range. Generates a synchronization clock of the reproduction signal by pulling in the synchronization.

FIG. 4 is a diagram showing the relationship between the command signal S1 and the control signal S3. Referring to FIG.
The maximum time width detector 13 measures the maximum time width of the reproduction signal to determine whether the reproduction signal is within the allowable synchronization range, and further compares the frequency of the reproduction signal with the set value set by the signal processor 9. . Thus, as in the case of the first embodiment, the output of the command signal S1 is "1" when the frequency of the reproduced signal is within the allowable synchronization range and when the frequency of the reproduced signal is smaller than the set value, and conversely, when the frequency of the reproduced signal is smaller than the set value. The output of the command signal S1 is "0" when the value is outside the allowable range and when the value is larger than the set value.

On the other hand, the rotation speed of the spindle motor 2 is detected as an analog rotation signal by the encoder 19, binarized by the waveform shaper 20, and output to the spindle controller 18b by the rotation speed detector 21 as a rotation speed signal.

Further, the spindle controller 18b controls the spindle control signal S3 to "OFF" according to the command signal S1 when the command signal S1 is "1". When the command signal S1 is "0", the spindle control signal S3 is controlled to "ON", and the peak value and / or the driving time are simultaneously changed according to the rotation speed signal to reach a predetermined rotation speed. Rotation drive control is performed until it reaches.

An example of controlling the peak value and the driving time in the spindle controller 18b will be described below. FIG.
Is a principle diagram for controlling the peak value and the driving time. In the figure, the rotation speed signal is once converted into a voltage signal corresponding to the rotation speed by the FV converter 31 and supplied to the gate of the FET 32. In the FET 32, the resistance between the source and the drain changes according to the gate voltage, and the resistance 33 connected in series is connected.
And a CR time constant composed of the capacitor 34 connected in parallel changes in accordance with the rotation speed signal.

Furthermore, the one-shot timer 35 triggered by the command signal S1 has a timer element of FET32,
The operation is performed with the CR time constant including the resistor 33 and the capacitor 34, and the spindle control signal S2 is obtained. Thus, a change in the drive time of the spindle control signal S2 based on the rotation speed signal is realized.

On the other hand, if the voltage signal of the FV converter 31 is output through the analog switch 36 only for the period of the spindle control signal S2 and is supplied to the spindle driver 8, the driving time based on the rotation speed signal and the peak value are obtained. A spindle control signal S3 based on both controls is realized.

As described above, according to the second embodiment of the present invention, the spindle motor 2 can be intermittently driven, and its driving content can be changed according to the peak value or the driving speed according to the current rotation speed of the spindle motor 2. Since the time or both are changed, finer drive control can be performed, and power consumption can be greatly reduced.

It is self-evident that the wider the allowable synchronization range in the combination of the synchronous clock generator 6 and the synchronous state determiner 17, the shorter the driving period in intermittent driving and the more the power consumption can be reduced. And
The description will not be repeated.

The effect of reducing power consumption will be described with reference to the drawings. FIG. 6 is a diagram illustrating a drive current of the spindle motor 2. In the figure, a period T1 shows a state in which the servo control is performing a steady rotation, a period T2 shows a state in which the servo control is turned off to perform an inertial rotation, and a period T3 shows that the servo control is turned on from off to on during acceleration rotation. Represents the state of. This example corresponds to the first embodiment because the servo control is simply turned on and off. In the figure, the current consumption is the period T
1 was observed at 130 mA, and the period T3 was observed at 260 mA, and the power consumption reduction effect was observed as a 25% reduction effect.

[0042]

As described above, the optical disk drive according to the present invention comprises: a synchronous clock generator for generating a clock synchronized with a reproduction signal; and a judgment as to whether or not the frequency of the reproduction signal is within a synchronization range. A synchronization state determiner to be performed, and a spindle controller that stops driving when the frequency of the reproduction signal is within the synchronization range, rotates the spindle by inertia, and drives and drives the spindle to enter the synchronization range just before the synchronization is out of the synchronization range. And

With the above arrangement, when reproducing data, if the frequency of the reproduction signal is within the synchronous range, the spindle motor is stopped and rotated by inertia, and the spindle motor is driven immediately before the synchronous signal is out of the synchronous range. It is possible to do.

Therefore, it is possible to provide an optical disk drive which realizes a great reduction in power consumption by intermittently driving the spindle motor.

In the above description, the synchronization state judging unit sets the reproduction signal within a synchronization allowable range slightly smaller than the synchronization range including the operation margin of the synchronous clock generator and the entire PLL circuit. It is determined whether there is a frequency or not and a command signal is output. because,
This is because, in order to reproduce large-volume data at high speed, in order to minimize the delay in response, a data read command is received, and data read is started immediately.

Therefore, when data is not accessed for a while, it is possible to reduce the power consumption by allowing the rotation speed to be changed beyond the synchronization range and further extending the drive suspension time of the spindle motor. Conceivable.

For the above purpose, instead of judging whether or not the frequency of the reproduction signal is within the allowable synchronization range, the access pause period is monitored, and the spindle motor according to the present invention is monitored. Driving pause control can be applied. Since this application is obvious to those skilled in the art, detailed description is omitted.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical disk drive according to a first embodiment of the present invention;

FIG. 2 is a diagram showing a relationship between a command signal S1 and a spindle control signal S2.

FIG. 3 is a configuration diagram of an optical disk drive according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between a command signal S1 and a control signal S3.

FIG. 5 is a principle diagram for controlling a peak value and a driving time.

FIG. 6 is a diagram showing a drive current of a spindle motor.

FIG. 7 is a block diagram of a conventional optical disk drive.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical disk 2 Spindle motor 3 Optical pickup 4 Servo controller 5 Reproduction signal detector 6 Synchronous clock generator 7 Rotation controller 8 Spindle driver 9 Signal processor 10 Voltage control oscillator (VCO) 11 Phase comparator 12 Loop filter 13 Maximum Time width detector 14 Frame detector 15 Reference oscillator 16 Phase comparator 17 Synchronization state determiner 18a, 18b Spindle controller 19 Encoder 20 Waveform shaper 21 Revolution detector 31 FV converter 32 FET 33 Resistance 34 Capacitor 35 One shot Timer 36 Analog switch

Claims (6)

(57) [Claims] An optical disk is irradiated with a laser beam,
The information of the optical disc is made to follow the recording information pits of the disc.
And information reading step of reading the broadcast, read information
An optical disc driving method comprising: a reproduction step of reproducing a reproduction signal from a reproduction signal; and a rotation driving step of driving the optical disk to rotate at a required number of rotations, wherein a synchronization clock for generating a synchronization clock for reproducing data from the reproduction signal is provided. A generating step, wherein the frequency of the reproduced signal is the same as the synchronous clock.
A synchronization state determination step than tuning range obtained from the operation margin of determining whether or slightly in the synchronization allowable range defined in a narrow range and outputs a command signal, in accordance with the command signal, the synchronous acceptable when in the range rotates by inertia and stops the rotation drive, if is outside the synchronization tolerance rotary drive system for the rotary drive
Controlling the optical disk. 2. An optical unit for irradiating a laser beam onto an optical disk and converting the reflected light into an electric signal, and a pickup unit comprising a drive unit for moving the optical unit in a radial direction of the optical disk and in a direction perpendicular to a recording surface of the optical disk. , The signal obtained from the pickup unit
And servo control means for driving the reproduced signal detecting means for outputting a No. reproduction signal, the optical unit to focus the laser beam on a predetermined position of the optical disk from the optical di
An optical disk drive device comprising: a rotation driving unit that drives and controls a disk to rotate at a predetermined number of rotations; and a signal processing unit that controls an entire optical disk device, wherein a synchronization clock for reproducing data from the reproduction signal is provided. Means for generating a synchronous clock, wherein the frequency of the reproduced signal is the synchronous clock and the operation of each means.
A synchronous state determination unit for outputting whether determined by a command signal is within synchronization allowable range set slightly narrower range than the synchronization range needed from work margin, in accordance with the command signal, in the synchronization tolerance Place in
In this case, the driving of the rotation driving means is stopped and the motor is rotated by inertia.
If the synchronization is out of the allowable range, the rotation driving means
Optical disk drive, characterized by chromatic and rotation driving control means for driving the. 3. An optical unit for irradiating an optical disk with laser light and converting the reflected light into an electric signal, and a pickup unit comprising a drive unit for moving the optical unit in a radial direction of the optical disk and in a direction perpendicular to a recording surface of the optical disk. , The signal obtained from the pickup unit
A reproduction signal detecting means for outputting a reproduction signal from a servo control means for driving said optical unit to focus the laser beam to a predetermined position of the optical disc, to control rotates the optical disc at a predetermined rotational speed a rotary drive means, there is provided an optical disk driving apparatus and a signal processing unit for controlling the entire optical disk device, a synchronous clock generating means for generating a synchronization clock for reproducing data from the reproduction signal, the reproduction signal A synchronization state determining unit that determines whether the frequency of the set value is within a set allowable range with respect to a set value set by the signal processing unit and outputs a command signal, based on the command signal, within the set allowable range. In some cases, the driving of the rotation driving means is stopped and the motor is rotated by inertia.
The rotation driving means
An optical disk drive device comprising: a rotation drive control unit that drives the optical disk. 4. An optical unit for irradiating an optical disk with laser light and converting the reflected light into an electric signal, and a pickup unit comprising a drive unit for moving the optical unit in a radial direction of the optical disk and in a direction perpendicular to a recording surface of the optical disk. , The signal obtained from the pickup unit
A reproduction signal detecting means for outputting a reproduction signal from a servo control means for driving said optical unit to focus the laser beam to a predetermined position of the optical disc, to control rotates the optical disc at a predetermined rotational speed a rotary drive means, there is provided an optical disk drive apparatus having a signal processing unit for controlling the entire optical disk device, a synchronization clock generating means for generating a synchronous clock for reproducing data from the reproduction signal, detecting the rotation of the optical disk and a rotation speed detecting means for generating a speed signal, dynamic frequency is the synchronous clock and the means of the reproduction signal
It is determined whether or not the frequency is within a synchronization allowable range that is slightly smaller than the synchronization range obtained from the work margin, and the frequency of the reproduction signal is set to a setting value set by the signal processing unit. Within range
A synchronous state determination unit for outputting a command signal in conjunction with duck determined, in accordance with the command signal, the synchronization allowable range a and before
When in serial set within the allowable range rotates by inertia and stops driving <br/> of the rotary drive means, the synchronization allowable range or
If that is outside the allowable setting range drive the rotary drive means
An optical disk drive, comprising: a rotating drive control unit that moves . 5. An optical disk drive according to claim 4, wherein said rotation drive control means changes a peak value of a drive output based on said rotation speed signal. 6. An optical disk drive according to claim 4, wherein said rotation drive control means changes a drive time of a drive output based on said rotation speed signal.