JP2000251389A - Optical disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk reproducing device, in which a target revolving speed is obtained without using a rotation detecting element in the case that the precision of the number of revolutions during a reproducing is not relatively required. SOLUTION: By utilizing of the characteristic capable of keeping a data reproducing speed constant without using a revolving speed detecting element in a CLV reproducing, and the relationship among the linear velocity on an optical the reproducing speed and the revolving speed, a motor 2 is driven by the signals obtained by averaging EC signals, for determing the motor driving signals in the CLV reproducing by an averaging section 12 and compensating the average EC signals by an output compensating section 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to CAV control in an optical disk device.

[0002]

2. Description of the Related Art An optical disk reproducing apparatus shown in FIG. 7 is a block diagram of a CAV (constant angular velocity) reproducing system using a Hall element. The optical disk 1 is driven to rotate by a spindle motor 2, and the signal of the optical disk 1 is detected by an optical pickup 3. The rotation of the spindle motor 2 is detected by the Hall element 4.

An output signal f from the Hall element 4 is converted into a general FG signal g via a driver integrated circuit 5. The FG signal g is a digital signal processor (hereinafter, referred to as a digital signal processor).
DSP 7). Optical pickup 3
Are input to the DSP 7 via the head amplifier 6. h is an EC signal, and i is a motor drive signal.

FIG. 8 shows the timing of each signal. This C
In the AV reproduction, the rotation of the motor 2 is detected, and a three-phase output signal f is output from the Hall element 4. An FG signal g is generated based on the output signal f, and the number of rising edges of the FG signal is counted. Then, the motor drive signal i is output from the EC signal h generated based on the deviation from the target through the drive circuit 8 of the driver integrated circuit 5, and the CAV is output. Control.

As described above, the reason why the conventional CAV reproducing method detects and controls the number of rotations of the disk by using the rotation detecting element represented by the Hall element 4 is shown in FIGS.
The EC signal h for keeping the number of rotations constant must be changed due to the ambient temperature indicated by a solid line, different loads (changes in inertial weight depending on the disk thickness and diameter), and the linear velocity of pits described on the optical disk. It depends.

Further, it is necessary to control the EC signal h even during CAV reproduction. FIG. 12 shows an EC signal during CAV reproduction. In FIG. 12, the dashed line is the high-speed speed EC signal, and the solid line is the low-speed speed EC signal. However, depending on the motor, the control width of the EC signal required for constant rotation in the low rotation region becomes smaller.

Next, a conventional CLV (constant linear velocity) reproducing method will be described below. In FIG. 13, j is an RF signal generated at the output of the head amplifier 6, and k is the D signal.
An EFM signal generated inside SP7, 1 is a reference clock, m is an EC signal, and n is a motor drive signal. This C
In the LV reproduction, a signal on the optical disk 1 is captured by the optical pickup 3 and an RF signal j as shown in FIG. The RF signal j is compared with a binarized EFM signal k via a DSL circuit 9 and a comparison unit 10 formed of a PLL circuit or the like using a reference clock l to generate an EC signal m. Is used to generate a motor drive signal n to perform CLV control. The timing is shown in FIG. FIG. 15A shows a case where the EFM is short (3
FIG. 15B shows the control waveform when the EFM is long (11T).

At this time, the output of the rotation detection of the three-phase motor is not required, and the CLV can be reproduced by the DC motor. As described above, CLV reproduction can be realized by using the signal on the optical disk 1 without using the rotation speed detecting element. As a mechanism for measuring the linear velocity of pits recorded on the optical disc 1, a method of measuring the linear velocity from the data reading time in a certain section during CLV reproduction will be described as an example.

As shown in FIG. 16, a time measurement section is determined in advance, and a time T required for reading is measured. Next, FIG.
The linear velocity on the optical disk is measured by converting the time required for reading into the linear velocity on the optical disk using the relationship At the time of CAV reproduction, the linear velocity is measured in the same manner.

[0010]

Since the conventional Hall element 4 required for CAV reproduction is expensive, it is required to further simplify the system for CAV reproduction and to perform CAV reproduction without the Hall element. In addition, even with a control method that only applies a constant voltage, a motor that has a small variation in the number of revolutions during reproduction at low revolutions has appeared. Therefore, it is desirable to perform control that removes the rotation detection element and keeps the EC signal constant. ing.

The accuracy of the EC voltage control required at a relatively low rotational speed is not so high, so that the rotational speed is constant without much difference from the conventional CAV control only by the constant output control. However, the constant output indicated by the dotted lines in FIGS. 9, 10, and 11 has a large difference from the CAV control indicated by the solid line, and the reproduction cannot be performed at the target rotation speed.

An object of the present invention is to solve the above-mentioned conventional problems when the accuracy of the rotational speed during reproduction is relatively not required, and to provide an optical disk reproducing apparatus capable of coping with various external factors. With the goal.

[0013]

In order to solve the above-mentioned problems, in CLV reproduction, the characteristic that the data reproduction speed can be kept constant without using the rotation speed detecting element, the linear velocity on the optical disk, the reproduction speed, and the rotation speed. The relationship is utilized to average the EC signal for determining the motor drive signal during CLV reproduction, and the motor is driven by the corrected signal.

According to this configuration, when the accuracy of the rotational speed during reproduction is relatively not required, the target rotational speed can be realized without the rotation detecting element.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical disk reproducing apparatus according to the present invention
An optical disk reproducing apparatus having a mechanism for performing CLV reproduction with a constant data reproduction speed and having a mechanism for detecting a linear velocity of an optical disk, wherein a voltage for measuring a motor drive signal during CLV reproduction or a signal for generating the drive signal is measured. A measuring unit, an averaging unit for averaging the signal measured by the voltage measuring unit, and an output correcting unit for correcting the averaged signal according to the linear velocity of the pits described on the optical disc,
A constant output section for outputting a signal corrected by the output correction section at a constant level and driving the motor to perform CAV reproduction in a constant angular velocity system.

According to this configuration, when the accuracy of the EC signal during reproduction is not required, CLV reproduction is used,
CAV reproduction can be performed without a rotation speed detecting element. Hereinafter, an embodiment of the present invention will be described with reference to FIGS. It is to be noted that components having the same functions as those of the conventional example will be described with the same reference numerals. FIG. 1 shows a schematic configuration of an optical disk reproducing apparatus according to the present invention. In FIG. 1, a is an RF signal, b is an EFM signal, c is a reference clock, d is an EC signal, and e is a motor drive signal.

As shown in FIG. 1, the optical disk reproducing apparatus has a conventional mechanism for performing CLV reproduction, and has a voltage measuring mechanism as a mechanism for detecting an EC voltage. As shown in FIG. 2, after the automatic adjustment of the optical disk and the linear velocity detection are completed, the CLV reproduction is performed. Next, the voltage measuring unit 11 shown in FIG.
, The EC signal is measured in a predetermined reproduction section, and the averaging unit 12 shown in FIG. 1 averages the EC signal shown in FIG.

As shown in FIG. 4, when the reproduction position is determined during CLV reproduction, the target rotational speed can be measured by using the fact that the number of revolutions at the reproduction position can be measured using the linear velocity on the optical disk. An error from the number is estimated, and the voltage correction of the averaged EC signal is performed by the output correction unit 13 to learn an EC voltage for performing CAV reproduction.

Using the learned EC signal, a constant output is output from a switch 15 and a driver IC 5 through a constant output unit 14.
Is applied to the spindle motor 2 via
Perform V playback. As shown in FIG. 2, the measurement, averaging, and correction of the EC signal are performed every time the media is changed, as in the automatic adjustment and the linear velocity detection.

As described above, the EC signal for keeping the number of revolutions constant according to the ambient temperature, different loads (changes in inertial weight depending on the disc thickness and diameter), and the linear velocity of the pits described on the optical disc is shown in FIG. 6 can be realized in the same manner as the conventional CAV control. Although the CAV reproduction of the present invention does not provide feedback on the rotation of the motor, the system is unstable because data is read from the optical pickup 3 shown in FIG. When the system is determined to be unstable based on the above-described criteria, the system is switched to CLV reproduction by utilizing the fact that the determination can be made without reading data, thereby preserving the system.

In the above embodiment, the voltage measuring unit 11 measures the voltage of the output of the comparing unit 10, but the voltage measuring unit 11
Does not measure the voltage of the output (input side of the driver IC 5) of the comparison unit 10 during CLV reproduction,
A similar effect can be expected even if the drive signal of the spindle motor 2 on the output side is configured to measure the voltage.

[0022]

As described above, according to the present invention, in CLV reproduction, the characteristic that the data reproduction speed can be kept constant without using the rotation speed detecting element, and the relationship between the linear speed on the optical disk, the reproduction speed and the rotation speed. The EC signal that determines the motor drive signal during CLV playback is measured and averaged, and a signal calibrated to a value corresponding to the linear velocity on the optical disc is output at a constant value to drive the motor, thereby rotating the motor during playback. In the case where the precision of the number is relatively not required, it is possible to realize a system that is simplified as compared with the related art without using the rotation detecting element for the target number of rotations, and it is possible to reduce the cost.

[Brief description of the drawings]

FIG. 1 is a block diagram of a CAV control in an optical disc reproducing apparatus according to the present invention.

FIG. 2 is a signal timing chart of the embodiment.

FIG. 3 is a diagram showing averaging of an EC signal according to the present invention;

FIG. 4 is a diagram showing the relationship between the data reproduction speed, the linear velocity of the optical disc when the position is fixed, and the number of revolutions of the present invention;

FIG. 5 is a view showing a change in an EC signal according to an ambient temperature when a disk rotation speed is constant according to the present invention;

FIG. 6 is a diagram showing a change in an EC signal according to the weight of an optical disk when the disk rotation speed is constant according to the present invention.

FIG. 7 is a conventional CAV control block diagram.

FIG. 8 is a timing chart of each signal during conventional CAV control.

FIG. 9 is a diagram showing a conventional EC signal change depending on the ambient temperature when the disk rotation speed is constant.

FIG. 10 is a diagram showing a change in an EC signal according to the weight of an optical disk when a conventional disk rotation speed is constant.

FIG. 11 is a diagram showing a conventional linear velocity at a constant disk rotation speed.

FIG. 12 is a diagram showing a conventional EC signal when the disk rotation speed is constant.

FIG. 13 is a conventional CLV control block diagram.

FIG. 14 shows an RF signal.

FIG. 15 is a timing chart of each signal during conventional CLV control.

FIG. 16 is a diagram showing a reading section for linear velocity detection;

FIG. 17 is a diagram showing a relationship between a reading time and a linear velocity of an optical disc;

[Explanation of symbols]

 Reference Signs List 1 optical disk 2 spindle motor 3 optical pickup 7 DSP 11 voltage measurement unit 12 averaging unit 13 output correction unit 14 constant output unit 15 switch a RF signal b EFM signal c reference clock d EC signal e motor drive signal

Claims (1)

[Claims] 1. An optical disk reproducing apparatus having a mechanism for performing CLV reproduction using a constant data reproduction speed method and having a mechanism for detecting a linear velocity of an optical disk, wherein the apparatus generates a motor drive signal during CLV reproduction or the drive signal. A voltage measuring unit for measuring a signal, an averaging unit for averaging the signal measured by the voltage measuring unit, and an output correcting unit for correcting the averaged signal according to the linear velocity of a pit described on the optical disc An optical disc reproducing apparatus, comprising: a constant output unit that outputs a signal corrected by the output correction unit and drives a motor, so as to perform CAV reproduction using a constant angular velocity method.