JP2009193652A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device accommodating load variation caused by vibration in the optical disk device for recording or reproducing information to/from a disk recording medium. <P>SOLUTION: The optical disk device is provided with a rotation means for rotating a recording medium, a means for setting rotation speed, a speed detecting means detecting speed, an integration means for integrating the target rotation speed and the present rotation speed, and an integration value limit means for limiting an integration value of the integration means to the prescribed value or less, limit operation of the integration value limit means is started at the time of change of the target rotation speed or at the time of start, and limit operation of integration value limit means is released when the prescribed time elapses or vibration is detected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a speed control device for controlling the rotational speed of a disc to a target rotational speed in an optical disc apparatus that records or reproduces information on a disc-shaped recording medium.

  In an optical disc apparatus, an optical disc is rotated using a spindle motor, and information is recorded on or reproduced from the optical disc using an optical pickup or the like. As a method for controlling the rotational speed of the spindle motor, there are CAV (constant angular speed) control for controlling the rotational angular speed constant, CLV (constant linear speed) control for controlling the linear speed constant, and the like. In recent optical disc apparatuses, DVDs are widely used as recording media such as video cameras. In DVDs, CLV (constant linear velocity) control with different angular velocities depending on the radial position of the disc is the mainstream.

  For example, in an optical disk apparatus such as a DVD, when moving an optical pickup from a user data area to a management information area, or when moving an optical pickup from a management information area to a user data area, a spindle motor according to the target radius position Need to change the speed.

  FIG. 4 is a block diagram of a conventional speed control apparatus using a speed control method. The spindle motor 401 is driven by a driver 408, and the FG unit 402 outputs a frequency signal that is shaped into a square wave according to the rotation speed of the spindle motor 401. The FV conversion unit 403 converts the square wave signal into a voltage corresponding to the rotation speed. In the target speed setter 405, a reference voltage corresponding to the target speed is supplied. The speed error detector 404 compares the output voltage of the FV conversion unit 403 with the voltage output from the target speed setter 405 and outputs a voltage that reduces the rotational speed error of the spindle motor 401. The voltage is amplified by gain 407 and input to integrator 406. The voltage integrated by the integrator 406 is converted into PWM by the PWM 410, smoothed by the LPF 409, and supplied to the driver 408.

  When the speed of the spindle motor 401 and the target speed are significantly different, the output of the speed error detector 404 is large because the difference between the output voltage of the FV conversion unit 403 and the output voltage of the target speed setter 405 is large. Input to the integrator 406. The speed difference signal input to the integrator 406 is integrated for maximum driving, but the overshoot increases due to the voltage integrated in the integrator. Therefore, the integrator 406 is provided with an integral value limiter 411 that limits the integral value. As a result, the speed overshoot at the time of speed change is reduced to approach the target speed.

For example, Japanese Patent Laid-Open No. 5-100750 discloses means for providing an integral value limiter in the integrator in the speed loop of the spindle motor in order to speed up convergence when changing the target speed.
Japanese Patent Laid-Open No. 5-100750

In the conventionally used speed control method as shown in FIG. 4, an integral value limiter 411 that limits the integral value of the integrator 406 is provided, so that the spindle motor 401 is overrun when the rotational speed is changed or is started. Shooting is reduced and convergence to the target speed is accelerated. However, the conventional optical disc apparatus does not consider vibration when applied to a portable device such as a video camera. When vibration occurs in the optical disc apparatus, the rotation shaft of the spindle motor 401 is pressed against the bearing, and the load on the spindle motor 401 increases. When the load on the spindle motor increases, the driving is limited by the integral value limiter, so that there is a problem that the speed of the spindle motor 401 is lowered and cannot be controlled.
In other words, the integral value limiter 411 provided in the integrator 406 is provided to reduce overshoot when the rotational speed is changed, and the spindle motor 401 cannot be driven with a value greater than the set limit value. Therefore, the speed control method described above has a problem in that when the spindle motor 401 continues to be overloaded due to vibration or the like during normal recording / reproduction, the speed of the spindle motor 401 decreases and cannot be controlled.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical disc apparatus capable of dealing with load fluctuations due to vibration while reducing overshoot in an optical disc apparatus for recording or reproducing information on a disc recording medium. .

  In order to achieve the above object, in the present invention, in an optical disc apparatus for recording or reproducing information on a disc recording medium, a rotating means for rotating the recording medium, and a target speed setting means for setting a target rotational speed of the rotating means Detecting means for detecting the speed of the recording medium, speed error detecting means for detecting a speed difference between the target rotational speed of the target speed setting means and the speed obtained by the detecting means, and the speed error detecting means Integrating means for integrating the output of the motor, a drive circuit for driving the rotating means based on the output of the integrating means, and an integral value limiting means for limiting the integral value of the integrating means to a predetermined value or less, and a target speed At the time of change or start-up, the limiting operation of the integral value limiting means is started, and after a predetermined time elapses or when vibration is detected, the optical data for canceling the limiting operation of the integral value limiting means is released. Disk apparatus.

  According to the present invention, in an optical disc apparatus that records or reproduces information on a disc recording medium, it is possible to cope with load fluctuations due to vibration while reducing overshoot when changing the target speed of the spindle motor. It becomes possible.

(Example 1)
Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing an embodiment of a spindle motor rotation control device of an optical disk device according to the present invention. In FIG. 1, an optical disc 100 that is a disc-shaped recording medium is attached to a spindle motor 101 and driven by the spindle motor 101. The pickup unit 114 irradiates the optical disc 100 with laser light and receives reflected light from the optical disc to record or reproduce information. The FG unit 102 outputs a frequency signal shaped according to the rotational speed of the spindle motor 101 into a square wave. The FV conversion unit 103 converts the square wave signal into a voltage corresponding to the rotation speed. As a result, the rotational speed of the recording medium can be detected. The target speed setter 105 is supplied with a reference voltage corresponding to the target speed. The speed error detector 104 compares the output voltage of the FV conversion unit 103 with the voltage output from the target speed setter 105, and outputs a voltage that reduces the rotational speed error of the spindle motor 101. . That is, the output of the speed error detector 104 is obtained by converting the speed difference of the spindle motor 101 with respect to the target speed into a voltage. The output of the speed error detector 104 is amplified by the gain 107 and input to the integrator 115. The integrator 115 starts the limiting operation of the integrator by the integral value limiter 111. The controller 112 sets the start and end timing of the limit operation of the integral value limiter 111 and the limit value. The output from the gain 107 is converted into PWM by the PWM 110, smoothed by the LPF 109, and input to the driver 108 which is a drive circuit for rotating the spindle motor 101. The timer 113 is set with a time-out period during the period during which the integral value limiter 111 performs the limiting operation. The timer counts the time from the setting of the target rotation speed until the output of the speed error detector elapses a predetermined time. The timeout time is set longer as the difference between the set target speed and the spindle motor 101 is larger.

  Next, FIG. 6 shows an example in which an optical disk device is mounted on a portable device such as a video camera. A waveform when vibration occurs due to a camera shake or the like during normal recording / reproduction is shown. The horizontal axis represents time, and the vertical axis represents the speed difference with respect to the target speed. FIG. 6A is a waveform when the video camera equipped with the optical disk device has no vibration. Although there are fluctuations in the eccentricity of the disk, the target speed of the spindle motor and the center value of the speed are almost the same. FIG. 6B is a waveform when vibration is generated in the integrator 115 in the spindle speed control loop in a state where the limiting operation of the integrated value limiter 111 is started. When vibration occurs in the optical disk device, the load on the spindle motor increases, and the driving is limited by the integral value limiter. As the vibration continues, the center value of the spindle motor speed further decreases. The amplitude in FIG. 6B indicates a speed difference in which the periodic vibration is applied to the optical disc apparatus and the speed of the spindle motor is fluctuating. When the driving of the spindle motor is restricted by the integral value limiter, the center value of the spindle motor speed decreases with respect to the target speed. If the speed difference with respect to the target speed exceeds ± 2%, the recording / reproducing operation is disturbed, and the normal recording / reproducing operation cannot be performed. FIG. 6C is a waveform when vibration occurs in a state where the limiting operation of the integrator 115 in the spindle speed control loop is not performed. Although the actual speed of the spindle motor fluctuates due to vibration, the center value of the speed does not decrease and is substantially the same as the target speed.

  Next, the operation at the time of changing the target speed of the spindle motor 101 will be described with reference to FIG. The horizontal axis represents time, and the vertical axis represents the speed difference with respect to the target speed. When t = 0, the target speed is set and the integrator starts a limiting operation. By setting an appropriate limit value in the integrator when the target speed is changed, speed overshoot can be reduced. When the target speed is within a predetermined range (for example, within ± 3%) (t = t1), the limiting operation of the integral value limiter 111 is terminated. Specifically, the controller 112 monitors the output of the speed error detector 104, and when the speed difference with respect to the target speed falls within a predetermined range, the controller 112 ends the limiting operation of the integral intelligence limiter 111. As described above, at the time of normal recording / reproduction, the limiting operation of the integral value limiter is ended, so that the spindle control can be performed without reducing the center value of the spindle motor speed due to vibration as shown in FIG. 6-3. It becomes possible.

  However, when the target speed is changed, vibration is generated and the load on the spindle motor increases, so that it may not converge to the target speed due to insufficient driving. If the speed does not converge to the target speed, the speed change operation of the spindle motor will not be completed, and recording / reproduction on the optical disk cannot be started. Specifically, input from a portable device such as a video camera cannot be recorded on the optical disc during recording, and information cannot be reproduced from the optical disc during playback. Therefore, a timer 113 is provided in the optical disc apparatus, and the controller 112 sets a timeout time in the timer 113 when setting the target speed. The timeout time is set to a time that does not affect the recording / reproducing operation. When the speed difference does not fall within the predetermined range within the time-out time set in the timer 113, the limiter setter 111 is released after the predetermined time elapses, that is, after the time-out time elapses (when t = t2). To do. By terminating the limiting operation after the timeout time elapses, it becomes possible to cope with load fluctuations due to vibrations and converge to the target speed.

  The operation at the time of changing the target speed of the spindle motor in the first embodiment will be described using the flowchart of FIG. In S <b> 201, the controller 112 starts the limiting operation of the integral value limiter 111, and sets a timeout time in the timer 113 according to the target rotation speed. In step S <b> 202, the controller 112 sets a target rotation speed in the target speed setting unit 105 and starts counting by the timer 113. The target speed setter 105 supplies a voltage corresponding to the target speed set by the controller. The speed error detector 104 outputs the difference between the voltage value from the target speed setter 105 and the voltage value obtained by converting the speed of the spindle motor into a voltage so that the output voltage from the speed error detector 104 becomes zero. Spindle control. In step S <b> 203, the controller 112 monitors the speed difference output from the speed error detector 104 and the count of the timer 113. When the speed difference of the speed error detector 104 is within ± 3% of the target speed, the controller 112 ends the limiting operation of the integrator limiter 111 in S205. After the limiting operation is completed, the recording / reproducing operation for the disk recording medium is started. Even if a load fluctuation due to vibration occurs during the recording / reproducing operation, the limiting operation of the integral value limiter 111 is completed, so that a stable recording / reproducing operation can be performed.

  However, when vibration occurs in the optical disk apparatus and the spindle motor continues to be overloaded, the speed difference of the speed error detector 104 does not converge within ± 3% of the target speed in S203. Therefore, it waits for the timer 113 to time out in S204. In S204, the time from the target speed setting time is compared with the time-out time set in advance in the timer to determine whether or not the time-out time has elapsed. The timeout time is set longer than the time required for changing the speed of the spindle motor 101 when changing the target speed. For example, the timeout time of the timer 113 is set to 5 seconds. If the predetermined time has elapsed in S204, the controller 112 ends the limiting operation of the integral value limiter 111 in S205 and ends the target speed changing operation. By providing a timeout, a stable recording / reproducing operation can be performed even when the optical disk apparatus continues to vibrate.

  The spindle motor startup time takes about 700 ms for the rotation speed to change from 0 Hz to 50 Hz, and about 1000 ms for the rotation speed to change from 0 Hz to 80 Hz. Therefore, the timeout time of the timer 113 may be changed according to the target speed.

(Example 2)
Next, the operation at the time of changing the target speed of the spindle motor in the second embodiment will be described using the flowchart of FIG. In this embodiment, a vibration detector 116 is provided in the optical disc apparatus, and the controller 112 is notified when vibration is detected by the vibration detector 116. First, in S501, the controller 112 starts the limiting operation of the integral value limiter 111, and the integral value of the integrator 115 is limited to a predetermined value or less. In S <b> 502, the controller 112 sets the target speed in the target speed setting unit 105. The target speed setter 105 supplies a voltage corresponding to the target speed set by the controller 112. In step S503, the controller 112 monitors the speed difference that is the output of the speed error detector 104. If the speed difference falls within a predetermined range (within ± 3% of the target speed), the controller 112 causes the integrator limiter 111 in step S505. End the limit operation. If the speed difference does not fall within ± 3% of the target speed in S503, the process proceeds to S504. In step S504, the controller 112 determines whether the vibration detector 116 has detected vibration. If no vibration is detected, the process returns to S503. If the vibration detector 116 detects vibration in S504, the controller 112 is notified that vibration has been detected, and the process proceeds to S505. In S505, the controller 112 ends the limiting operation of the integral value limiter 111. As a result, if vibration occurs when the target speed of the spindle motor is set, the controller 112 ends the limiting operation of the integral value limiter 111 even if the output of the speed error detector 104 does not fall within the predetermined range. As a result, convergence to the target speed is accelerated.

  As described above, the limit operation of the integrator is started when the speed is changed, and the limit operation of the integrator is not normally performed. Even if vibration occurs during normal recording / reproduction, the speed of the spindle motor is reduced and controlled. Does not become unstable. In addition, during the period during which the limiting operation is performed, the limit operation is terminated by a timeout or a vibration detector, so that it is possible to cope with load fluctuations during vibration.

It is a block diagram of the spindle motor speed control apparatus in a present Example. It is a flowchart which shows the operation | movement at the time of the target speed setting in a 1st Example. It is a figure explaining operation | movement when a vibration generate | occur | produces at the time of target speed change. It is a block diagram of the spindle motor speed control apparatus of a prior art example. It is a flowchart which shows the operation | movement at the time of target speed change in a 2nd Example. It is a waveform when vibration occurs in the optical disc.

Explanation of symbols

100 Optical disc 101, 401 Spindle motor 102, 402 FG section 103, 403 F-V converter 104, 404 Speed error detector 105, 405 Target speed setter 107, 407 Gain 108, 408 Driver 109, 409 LPF
110, 410 PWM
111, 411 Integral value limiter 112 Controller 113 Timer 114 Pickup 115, 406 Accumulator 116 Vibration detector

Claims (3)

In an optical disc apparatus for recording or reproducing information on a disc-shaped recording medium,
Rotating means for rotating the recording medium;
Target speed setting means for setting a target rotational speed of the rotating means;
Detecting means for detecting the rotational speed of the recording medium;
Speed error detecting means for detecting a speed difference between the target rotational speed of the target speed setting means and the rotational speed obtained by the detecting means;
Integrating means for integrating the output of the speed error detecting means;
A driving circuit for driving the rotating means based on the output of the integrating means;
An integral value limiting means for limiting the integral value of the integrating means to a predetermined value or less,
An optical disc apparatus characterized in that when the target speed is changed or activated, the limiting operation of the integral value limiting means is started, and the limiting operation of the integral value limiting means is canceled after a predetermined time elapses or when vibration is detected.   2. The optical disc apparatus according to claim 1, wherein the predetermined time varies depending on a target rotational speed of the target speed setting means.   2. The optical disk apparatus according to claim 1, wherein the integral value limiting means cancels the limiting operation of the integral value limiting means when the output of the speed error detecting means falls within a predetermined range.

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