JPH06176478A - Optical disk device - Google Patents

Abstract

PURPOSE:To make an eccentric amount a minimum value by measuring the synthesis eccentric amount of a disk turntable and preforming reload so as to cancel the eccentricity between a disk and the turntable. CONSTITUTION:By an actuator driving circuit 5, a current passing through a tracking servo coil 11 is controlled in the state of the rotation of the disk to apply a tracking servo in the radial direction of the disk. Then, the current passing through the coil 11 is converted to a voltage by a resistor 12. A waveform in both ends of the resistor 12 is the waveform superposing a bit component and a high frequency component due to a defect on a low frequency component synchronizing with the rotation of a spindle motor. The high frequency component is eliminated by an LPF 14, and only an eccentric component is left. The eccentric component is digitized through a peak holding circuit 16 and an A/D converter 17 to be fetched to a controller 7, and the eccentric amount value is decided, and when the value is too much, disk loading is released, and the phase between the disk and the turntable is changed. Then, the eccentric amount value is decided again. When the values are excess even in prescribed number of times of measurments, the disk is taken out and processed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device, and more particularly to an optical disk device having a combined eccentricity reduced by a remounting function so as to cancel the eccentricity of a disk and the eccentricity of a rotary table. is there.

[0002]

2. Description of the Related Art A technique for measuring the amount of eccentricity while the disc is mounted in a reproducing apparatus and moving the disc by an extrusion mechanism provided on the outer circumference of the disc based on the calculated amount of eccentricity is disclosed in Japanese Patent Laid-Open No. 60-170071. Known in. According to this method, it is possible to minimize the eccentricity of the disc.

[0003]

However, the above-mentioned prior art requires an external mechanism for correcting the eccentricity of the disk, and the disk clamp mechanism is complicated.

It is an object of the present invention to provide an optical disk device which is excellent in reading recorded information from a disk by creating a state with a small amount of eccentricity without providing an external mechanism for correcting the disk eccentricity. .

[0005]

SUMMARY OF THE INVENTION The above-mentioned object is to provide a disc in a normal reproducing state (mounted on a rotating table, rotating the disc,
Focus servo and tracking servo applied)
At, the current value flowing in the tracking coil or the voltage value applied to the tracking coil is measured by the eccentricity measuring circuit.

This eccentricity is measured a plurality of times with the rotational direction of the disc and the angular phase of the rotary table changed, and the total eccentricity of the state where the eccentricity of the disc and the rotary table is added and the state where the eccentricity is subtracted are measured. A range of quantities is required.

By repeating the state in which the rotation direction of the disk and the angular phase of the rotary table are changed so that the total eccentricity value is smaller than the range of the total eccentricity amount, reproduction with the minimum eccentricity amount can be achieved and achieved.

[0008]

Since the rotary table of the optical disk device is composed of a combination of a spindle motor and a tapered centering hub having a centering and holding function for the disk, it has a slight eccentricity.

The combined value of the eccentricity of the rotary table and the eccentricity of the disk is the eccentricity value for the pickup.

The voltage value applied to the tracking coil in a normal reproducing state of the disk draws a sine curve synchronized with the rotation of the disk, and its amplitude value is a value proportional to the eccentricity of the disk and the combined eccentricity of the rotary table.

The eccentricity measuring circuit detects the combined eccentricity value from the voltage amplitude value applied to the tracking coil.

The control unit stores the combined eccentricity value.

Next, the mounted state of the disc is released according to an instruction from the control unit, and the rotary table is randomly rotated for a short time while the disc is floated above the rotary table, and the disc is mounted again.

As a result, the phase of the disc and the rotary table in the direction of rotation is different from that in the previous mounting, and the combined eccentricity value is also different.

As described above, by repeating the attachment / detachment and measuring the eccentricity to fix and reproduce the mounted state with a small eccentricity, it is possible to read out the recorded information well.

[0016]

An embodiment of the present invention will be described below with reference to the drawings.

The operation of the disc reproducing apparatus capable of reading the disc recorded information in a state where the combined eccentricity is small will be described with reference to FIGS. 1 to 6.

The disc 1 mounted in the disc reproducing apparatus shown in FIG. 1 has an eccentricity C when the disc hole 9 is displaced from the recording track 10 on which information is recorded.
Is the value of AB.

An eccentricity is also provided between the spindle motor 3 and the rotary table 2 shown in FIG. 1 as shown in FIG. 3, and between the rotary shaft 3a of the spindle motor 3 and the centering hub 2a, and the tapered portion 2b of the centering hub 2a. The eccentricity F becomes a value of D-E due to the processing accuracy of the above, etc.
The combined eccentricity F and the combined eccentricity F are combined eccentricity G.

The combined eccentricity G differs depending on the state of the disk 1 mounted on the centering hub 2a. The eccentricity C of the disk 1 and the eccentricity F of the rotary table 2 and the added state indicate that the eccentricity C of the disk 1 and the eccentricity F of the rotary table 2 are different. Has a range up to and subtraction.

The basic operation of disk reproduction is the operation flow chart shown in FIG.
As shown in FIG. 2, a new disc is mounted, the operation starts from operation S1, the slider motor 8 is rotated by the instruction of the controller 7 shown in FIG. 1, the disc 1 is taken into the disc reproducing apparatus, and further mounted and clamped on the rotary table 2. .

Upon completion of the mounting, the actuator drive circuit 5 controls the current flowing through the focus coil in the optical circuit 4 according to an instruction from the controller 7. Focus servo is applied in the vertical direction of the disk 1.

Next, the spindle motor 3 is rotated according to an instruction from the controller 7, and the rotary table 2 combined with the spindle motor 3 is rotated.

While the disk 1 mounted on the rotary table 2 is rotating, the actuator drive circuit 5 controls the current supplied to the tracking coil in the optical circuit 4 according to an instruction from the controller 7. Tracking servo is applied in the radial direction of the disk 1.

In the eccentricity measurement S2 shown in FIG. 6 with the tracking servo applied, the current flowing in the tracking servo coil 11 incorporated in the optical head 4 shown in FIG. 4 is converted into a voltage value by the resistor R12. .

The voltage waveform across the resistor R11 is C in FIG.
A pit component and a high-frequency component 19 due to a defect are placed on the low-frequency component 18 synchronized with the rotation speed of the spindle motor 3 as shown in FIG.

The waveform of C1 is taken out by the buffer amplifier 13, and the high-frequency component 19 is removed by the low-pass filter 14 consisting of a coil and a capacitor, so that only the eccentric component 20 shown by C2 is obtained.

Further, the controller 7 takes in the amplitude value V of C2 digitized by the peak hold circuit 16, the analog / digital converter 17, and determines whether or not the value of the combined eccentricity G is too large. Determination S3 is performed. When the value of the eccentricity amount G is small according to the eccentricity amount judgment S3 of the controller 7, it is judged as OK, and the reading S12 of the information recorded on the disc is performed.

When the amount of eccentricity is large as determined by the eccentricity amount determination S3, the disc mounted state is released S4, the spindle motor is then rotated S5, and the phases of the disc 1 and the rotary table 2 are switched. By changing this phase, the combined eccentric amount G of the eccentric amount C of the disk 1 and the eccentric amount F of the rotary table 2 differs from the previous state.

In this state, the eccentricity amount measurement S7 and the eccentricity amount determination S8 are performed again, and when the eccentricity amount is small, information reading S12 is performed. When the amount of eccentricity is large, a judgment S9 is made whether the number of times the disk 1 and the rotary table 2 are attached / detached is within a predetermined number. If the number exceeds the specified number, the disk defect display S11 is performed together with the disk removal process. To do.

The combined eccentric amount G of the eccentric amount C of the disc 1 and the eccentric amount F of the rotary table 2 is minimized by changing the phase difference between the disc 1 and the rotary table 2 from S4 to S8. By doing so, it is possible to create an optimum mounting state for reading the information recorded on the disc.

[0032]

According to the present invention, the external mechanism for correcting the eccentricity of the disk is not necessary, and the eccentricity can be brought close to the minimum value without the complicated disk clamp mechanism.

Further, the accuracy of eccentricity between the rotary shaft 3a of the spindle motor 3 and the centering hub 2a can be increased.

[Brief description of drawings]

FIG. 1 is a main configuration diagram as an embodiment of the present invention.

FIG. 2 is a diagram showing an eccentric state of a disc.

FIG. 3 is a diagram showing an eccentric state of the disc reproducing apparatus.

4 is a configuration diagram of an eccentricity amount measurement circuit shown in FIG.

FIG. 5 is an eccentric waveform diagram of an eccentricity measurement circuit.

6 is an operation flow chart in the embodiment shown in FIG. 1. FIG.

[Explanation of symbols]

1 ... disk, 2 ... rotary table, 5 ... eccentricity measuring circuit, 7 ... controller.

Claims (1)

[Claims] 1. An eccentricity measuring circuit for measuring an eccentricity of a disk and a combined eccentricity of a disk rotary table in an optical disk device for obtaining desired information from a rotating disk-shaped optical recording medium (hereinafter referred to as a disk). And an optical disk device having a function of remounting so that the eccentricity of the disk and the rotary table is canceled.