JPS60185253A - Disc eccentricity absorbing means of disc device - Google Patents

Abstract

PURPOSE:To reduce the eccentricity of a disc by detecting the disc eccentricity from a tracking error signal, and rocking a disc driving part in accordance with the prescribed frequency of a disc so that the eccentricity is reduced. CONSTITUTION:A disc motor 2 and the disc 1 are driven at the prescribed rotational frequency. A detecting part 30 detects the disc eccentricity as a tracking error signal and the signal is turned to a sine wave signal 42' corresponding to the disc eccentricity through a detecting circuit 40, a control circuit 41 and an LPF42. The signal 42' is shifted by 180 deg. at its phase by a phase delay circuit 43 and inputted to a driving means 20 through a driving circuit 44 and an amplifier 45 and the output of the means 20 rocks a disc driving part 5 in the tracking direction in accordance with the prescribed rotational frequency of the disc 1 by the quantity corresponding to the eccentricity. Thus, the eccentricity of the disc is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a disk eccentricity absorbing mechanism for reducing the amount of disk eccentricity in a disk device.

[Background of the invention]

A disk device comprising a disk drive section that holds a disk and performs a predetermined rotation, a detection section that records or reproduces information signals on the disk, and a detection section drive section that operates the detection section in the radial direction of the disk, When a disk is held in a disk drive section, the amount of eccentricity becomes larger than the eccentricity in the disk drive section and the disk.

Generally, the disc eccentric lid has a rotation speed of ±80 at RFR foot rotation speed (1800R for original method, 5oHz for GM).
μm, and the mechanical system has the same amount of eccentricity due to the accuracy of the mechanical parts, and the total amount of eccentricity must be controlled by the actuator of the detection unit to about ±160 minutes, and the dynamic range of the actuator is ± It has a thickness of about 600 μm.

However, in the dynamic range of the actuator, in a range of ±100 fine or more, the driving method of the objective lens changes from parallel operation to rotational operation, resulting in a decrease in both detection sensitivity and frequency characteristics, resulting in a decrease in image quality.

In addition, even for a single disk, the eccentricity is specified to be ±80 μm, but due to defects during disk manufacturing or wear of the center hole during use, the eccentricity is ±300 to 500 μm.
There are also disks that have a large amount of eccentricity, and the problem arises that information signals cannot be recorded or reproduced on these disks.

Furthermore, this eccentricity causes an effect not only in the tracking direction, but also in the jitter direction (direction perpendicular to the tracking direction), causing color unevenness and the like.

Therefore, it is desired that the total eccentricity of the disk when the disk is held in the disk drive section be as small as possible.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a disk eccentricity absorbing mechanism for a disk device that solves the above-mentioned conventional problems and reduces disk eccentricity that occurs when a disk is held in a disk drive unit.

[Summary of the invention]

The basics of the present invention are to detect the amount of disk eccentricity that occurs when the disk is held in the disk drive section from the tracking error signal of the detection section, and to adjust the disk drive section to a predetermined rotation speed of the disk so as to reduce the detected amount of disk eccentricity. This is done by correspondingly swinging in the tracking direction.

That is, the disk device is provided with a guide mechanism for enabling the disk drive section to move in the tracking direction, and a drive mechanism for driving the disk drive section in the tracking direction via the guide mechanism section, and also for moving the disk in a predetermined position. When rotating at the rotational speed, the detection unit detects the amount of disk eccentricity (
This detection signal is used to control the drive mechanism at a frequency corresponding to a predetermined number of rotations of the disk (in the case of the original method, 1800 r, p, m, 30
H2), and by driving at the same level as the disk eccentricity and with a phase difference of 180°, the disk drive section is oscillated in the tracking direction to reduce the disk eccentricity.

[Embodiments of the invention]

FIG. 1 is a block diagram showing an embodiment of an eccentricity absorbing mechanism of a disk device according to the present invention. FIG. 2 is a diagram showing signal waveforms of important parts in FIG. 1, and FIG. 3 is a diagram showing another embodiment of the drive mechanism for swinging the disk drive unit. FIG. 4 is a diagram showing changes in the disk drive unit swing lid in FIG. 3. FIG.

In each figure, 1 is a disk, 5 is a disk motor 2.
and a turntable 3 for holding the disc 1.
10 is a guide mechanism section for guiding the disk drive section 5 in the disk radial direction (tracking direction); and 20 is a drive mechanism, which in FIG. 1 is a beam near motor 29. In FIG. 3, the bin 23 is rotated by an eccentric cam 22 rotated by a rotary motor 21.
A lever 24 that can be freely swung around. A pinion 26 meshing with a rack 25 for sliding the eccentric force cam 22 onto the lever 24. and a pulse motor 27 for rotating the pinion 26. 30 is an objective lens 61. A detection section includes an actuator 32 and the like; 40 is a detection circuit that inputs a tracking error signal from the detection section 30; 41 is a control circuit; and 42 is a low-pass filter.

42' is the detection signal from the low-pass filter, 46 is the phase delay circuit, Δ3° is the output signal from the phase delay circuit 43,
44 is a drive circuit, and 45 is an amplifier. Further, 45' is a drive signal to the drive mechanism 20.

Next, the operation of this embodiment will be explained using each figure.

First, explanation will be given using FIGS. 1 and 2.

Note that the drive mechanism 20 in FIG. 1 is the linear motor 2.
9 is used. In this embodiment, since the disk drive section 5 is pulled in the tracking direction (the middle direction in FIG. 1) by the guide shaft 11 and tension spring 12 of the guide mechanism section 10, the disk motor 2 of the disk drive section 5 is , is pressed by a lever 24 that constitutes the drive mechanism 20.

Here, with the disk 1 placed on the turntable 3 of the disk drive section 5 and held by the holding section 6, the disk motor 2 and the disk 1 are driven at a predetermined rotation speed.

Therefore, while moving the detection unit 30 in the tracking direction by a detection unit drive unit (not shown), the actuator 32 is driven via the detection circuit 40 and the control circuit 41 using the detection signal from the detection unit 30, and the objective lens 31 is driven. The information signal is recorded or reproduced by controlling the light beam in the well-known tracking direction and focus direction and appropriately controlling the light beam from the detection section 50 to the track 1' of the disc 1.

By the way, when the disk 1 is held by the disk drive unit 5, the disk 1 is slightly eccentric due to the eccentricity of the disk drive unit 5 and the disk itself, and due to this eccentricity, when the disk 1 is driven at a predetermined rotation speed, Track 1'' on the disk 1 moves by a predetermined amount of eccentricity in the tracking direction, but in the present invention, the detection section 60 detects the amount of disk eccentricity as a tracking error signal, and further utilizes this detection signal to detect the amount of eccentricity. The disk eccentricity is reduced by driving the drive mechanism 20 and swinging the disk drive unit 5 in the tracking direction by an amount corresponding to the eccentricity in accordance with a predetermined rotational speed of the disk.

That is, in a state where the disk 1 is driven at a predetermined rotational speed and the track 1' is moving in the tracking direction due to disk eccentricity, a tracking error signal of 6 degrees is transmitted to the detection section 4 through the detection circuit 4 and the control circuit 41. ,
Although the objective lens 31 is controlled in the tracking direction,
Here, the signal from the control circuit 41 is filtered through the low-pass filter 4.
2, the detection signal 42.2 extracts a predetermined rotation speed (30 Hz in the case of the American method) component. In other words, in Figure 2 (aJ
Obtain a roughly sine wave signal shown by .

Therefore, this detection signal 42' is input to the phase delay circuit 43, and the phase delay circuit 46 obtains an output signal 43' (indicated by bl in FIG. 2) whose phase is shifted by 1800 degrees.

Further, via the drive circuit 44 and the amplifier 45, a drive signal 45' (indicated by C1 in FIG. , this drive signal 45' is sent to the drive mechanism 20
When supplied to Since the objective lens 31 of the detection unit 30 is oscillated in the tracking direction by
Considering this, it works to cancel the amount of eccentricity of the disk 1, and as a result, the level of the amount of disk eccentricity is almost zero from the detection unit 30, and the signal shown by dl in FIG. It is done.

Next, another embodiment of the drive mechanism 20 for swinging the disk drive section 5 will be described with reference to FIGS. 3 and 4. FIG. In FIG. 1, a linear motor 29 is used as the drive mechanism 2o, but here, a disk eccentricity absorbing mechanism is used in which a rotary motor 21 is used.

That is, in this drive mechanism 2o, the eccentric cam 22, which is eccentric by a predetermined amount, is rotated by the rotational force of the rotary motor 21.
The rotation of the eccentric cam 22 causes the lever 24 to swing, and since the pulley 4 fixed to the shaft of the disk motor 2 of the disk drive section 5 is in contact with the lever 24, the swinging action of the lever 24 causes the pulley 4 to swing. The disk drive section 5 can be operated in the direction of the arrow A or B in the figure through this, and as described above, the disk eccentricity can be reduced.

The eccentric cam 22 is moved by the operation of the rack 25 that meshes with the pinion 26 rotated by the pulse motor 27.
Since it can be moved in the direction of arrow C or D in the figure together with the rotary motor 21, etc., the distance from the bin 23 to the point where the eccentric cam 22 contacts the lever 24i/C (the part indicated by l in FIG. 3) can be changed. As shown in the characteristic shown in FIG. 4, the swing amount δ of the disk drive unit 5 can be linearly changed by changing l.

That is, the level of the drive signal 45' indicated by tel in FIG. Drives the motor 27 and lever 240
Distance l from the rotation center of the bin 23 to the eccentric cam 22
Set. Therefore, the rotary motor 21 that rotates the eccentric cam 22 is rotated so as to have a phase difference of 180° with respect to the detection equal sign (indicated by tal in FIG. 2) generated by the amount of disk eccentricity, and the disk drive unit 5 is oscillated. By moving,
At the position of the detection unit 300 and objective lens 31, the amount of disk eccentricity can be made almost zero.

According to experiments, when the amount of disk eccentricity was about 200 capes, by using the disk eccentricity absorbing mechanism of the present invention, it was possible to significantly reduce the amount of disk eccentricity to 10 μm or less.

〔Effect of the invention〕

As described above, in the disk device equipped with the disk eccentricity absorbing mechanism of the present invention, the amount of disk eccentricity of the disk held in the disk drive unit and rotated at a predetermined number of rotations is detected by the detection unit as a tracking angle signal. However, by swinging the disk drive unit in the tracking direction with a phase difference of 1800 degrees from the phase of the disk eccentricity and at a level equivalent to the disk eccentricity, the disk eccentricity can be reduced to almost zero at the objective lens position of the detection unit. Therefore, the operation of the actuator in the detection section can be used with optimal characteristics, and image quality can be improved.

In addition, even with disks that have a large amount of disk eccentricity that could not be used conventionally due to defects in disk manufacturing or center hole wear, etc., it is possible to reduce the amount of disk eccentricity and use it with good characteristics. A highly reliable disk device can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the disk eccentricity absorbing mechanism of the disk device of the present invention, FIG. 2 is a waveform diagram showing the signal waveforms of the main parts in FIG. 1, and FIG. A block diagram showing another embodiment of the drive mechanism for swinging. FIG. 4 is a diagram showing changes in the amount of swing of the disk drive section in FIG. 6. 1... Disk 2... Disk motor t 5... Disk drive section 10... Guide mechanism section 20... Drive mechanism 29... Linear motor 30... Detection section l Figure 2 Figure 3

Claims (1)

[Claims] 1) A disk drive section that holds the disk and rotates the disk at a predetermined rotation speed, a detection section that records information signals on the disk or reproduces the recorded information signals, and a detection section that moves the detection section in the radial direction of the disk. In a disk device comprising a detecting section drive section that operates, a guide mechanism section for enabling the disk drive section to move in the tracking direction of the detecting section; and a guide mechanism section for moving the disk drive section in the tracking direction via the guide mechanism section. A driving mechanism is provided, and the amount of eccentricity of the disk when the disk is being rotated at a predetermined rotational speed is detected by the tracking error signal of the detection section, and the detection signal is used to determine the predetermined rotational speed of the disk. The drive mechanism is driven to swing the disk drive unit in the tracking direction at a predetermined frequency corresponding to the disk eccentricity, at a level equivalent to the disk eccentricity, and with a phase difference of approximately 180 degrees. Disk eccentricity absorption mechanism for disk devices.