JPH03237653A - Method for driving disk medium - Google Patents

Abstract

PURPOSE:To reduce an eccentricity quantity caused by the positional deviation between the hub center hole of a disk medium and a spindle center by rotating a mechanism for rotating and driving the disk medium at high speed at first in a state holding the mechanism allowing the disk medium to be rotated and drived and returning the speed of revolution to prescribed usual one. CONSTITUTION:In an optical disk 20, the hub center hole 25 is inserted into the center axis 14 of a spindle 10 and the disk is loaded on the spindle 10. Prior to the rotation of the optical disk 20 at usual rotation, the spindle 10 is rotated at high speed and it is returned to prescribed usual rotation. Thus, the rotational force of the disk medium 20 is superior to friction force between the disk medium 20 and a spindle 10-side by magnetic adsorbing force even if the disk medium 20 is loaded in the state with much eccentricity quantity and minute slippage occurs between the disk medium 20 and the spindle 10. Thus, the eccentricity quantity caused by the positional deviation between the hub center hole 25 of the disk medium 20 and the spindle 10 center can be reduced.

Description

[Detailed Description of the Invention] [Summary] A method of driving a disk medium in which the disk medium is held and driven by a mechanism that rotationally drives the disk medium, which is caused by misalignment between the center hole of the hub of the disk medium and the center of the spindle. A method for driving a disk medium, the purpose of which is to reduce the amount of eccentricity as much as possible, and the method comprises: first rotating the mechanism at high speed while holding the disk medium in the mechanism, and then returning to a predetermined normal rotation. Configure.

[Industrial application field]

The present invention relates to a method for driving a disk medium, particularly for writing and reading information on an optical disk or a magnetic disk, etc.
The present invention also relates to a method of driving a convertible disk medium by magnetically attracting and holding it to a mechanism that rotationally drives the disk medium.

In a device that drives a disk medium by attaching it to the main body of the disk device, there is a method of clamping the disk medium to the spindle of the main body drive unit using magnetic force as described above. It is required to minimize the amount of eccentricity caused by positional deviation between the disk and the center of the spindle, and to ensure stable rotation of the disk medium and stability of track scanning by the recording head.

[Conventional technology]

Conventionally, a method is already known in which a disk medium is clamped to a spindle of a drive unit of an apparatus main body using magnetic force as described above. According to the driving method of this kind of disk media,
The center of the disk medium is aligned by inserting the center hole provided in the hub of the disk medium into the spindle, while the hub part of the disk medium is made of metal and a magnet fixed to the spindle side aligns the center of the disk medium. The disk medium is clamped to the apparatus main body by magnetically attracting the hub.

FIG. 5 shows the conventional procedure for loading an optical disk medium, and FIG.
The figure shows the state after the disk medium is installed. In these figures, on the spindle 10 side of the optical disk device, a dish-shaped support member 12 made of resin or metal for receiving a disk medium is fixed on the spindle main shaft 11, and a plate-shaped support member 12 made of resin or metal is fixed on the inside of the upper surface. An annular magnet 13 is fixed, and a shaft 14 with a tapered or rounded upper end for determining the center position protrudes from the center.

The peripheral edge of the support member 12 is located above the upper surface of the magnet 13. On the other hand, on the optical disk 20 side, a hub 24 made of resin or the like is fixed to both sides of the center of a medium 23 made by bonding two circular substrates 21 and 22 so that both sides can be used. A ring-shaped magnetic metal 26 is fixed to the upper and lower surfaces around the center hole 25. this metal 2
6 exists up to the center hole 25, and strengthens the wear resistance of the center hole 25.

To load the optical disc 20 onto the spindle 10, insert the hub center hole 25 of the optical disc 20 into the central shaft 14 of the spindle 10 using a loading device (not shown) or the like.
The state is as shown in FIG. At this time, optical disc 2
The inner periphery of the medium 23 on the outside of the hub 0 contacts the periphery of the support member 12 on the spindle 10 side (A in the figure), while the ring-shaped metal 26 of the hub 24 does not contact the magnet 13 but is close to it. position (B in the figure), the magnet 13 exerts a magnetic attraction force on the ring metal 26, and the optical disc 20
is chucked and held by the spindle 10.

As is well known, the optical disk 20 is rotated by the spindle 10, and information is written, read, or converted onto the medium 23 by an optical head (not shown). When the optical disk 20 rotates, the magnetic attraction force exerted by the magnet 13 on the ring metal 26 generates a frictional force at the contact area between the peripheral edge of the support member 12 and the inner peripheral area of the medium 23. The optical disk 20 is attached to the spindle 10
It is held in the center position.

[Problem to be solved by the invention]

However, in order to facilitate mounting of the optical disc 20, the hub center hole 25 is made slightly larger than the central axis 14 of the spindle 10, so that the optical disc 20 may be mounted eccentrically with respect to the spindle 10. There is. If this amount of eccentricity becomes large, it is not preferable because it affects the stable rotation of the optical disk 20 and the stability of track scanning by the recording head.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for driving a disk medium that can minimize the amount of eccentricity caused by the misalignment between the hub center hole of the disk medium and the center of the spindle.

[Means to solve the problem]

In order to solve such problems, according to the present invention, as shown in FIG. There is provided a method for driving a disk medium, characterized in that the mechanism 10 is first rotated at high speed while the mechanism 20 is held by the mechanism, and then returned to a predetermined normal rotation.

[For production]

According to the present invention, even if the disk medium 20 is mounted on the spindle 10 with a large amount of eccentricity, the disk medium 20
0 is initially rotated at a higher rotation than normal rotation, the rotational force of the disk medium 20 overcomes the frictional force between the disk medium 20 and the spindle 10 due to the holding force, and the rotational balance of the disk medium 20 is maintained. For best results, a slight slippage occurs between the disk medium 20 and the spindle 10, thereby correcting the eccentricity.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, in FIG. 1, the structure is similar to the conventional optical disk device shown in FIGS. 5 and 6, and 10 is a spindle (i.e., a mechanism for rotationally driving the disk medium) on the device main body side; 11 is a main shaft, 12 is a support member, 13 is a magnet, and 14 is a center positioning shaft. On the other hand, 20 is an optical disk mounted on the spindle 20, 21, 22 is a medium substrate, 23 is a medium, 24 is a hub, 25 is a center hole, and 26 is a magnetic metal. The optical disk 20 is mounted on the spindle 10 by inserting the hub center hole 25 into the center shaft 14 of the spindle 10, and at this time, the inner circumference of the medium 23 outside the hub of the optical disk 20 is on the spindle 10 side. A shown in the figure contacts the peripheral edge of the support member 12.
), on the other hand, the ring-shaped metal 26 of the hub 24 does not come into contact with the magnet 13 but is in a close position (B in the figure), and the magnet 13 exerts a magnetic attraction force on the ring metal 26, causing the optical disk 20 to move toward the spindle 10. The point that it is held by a chuck is the same as the conventional one.

However, in the present invention, the spindle is then rotated at high speed before the optical disk 20 is rotated in a normal rotation, and then returned to a predetermined normal rotation. As a result, even if the disk medium 20 is initially installed with a large amount of eccentricity, the rotational force of the disk medium 20 overcomes the frictional force between the disk medium 20 and the spindle 10 side due to the magnetic attraction force, and the disk A slight slip occurs between the medium 20 and the spindle 10, and the eccentricity is corrected.

FIG. 2 is a diagram showing a method of measuring such an amount of eccentricity and an amount of correction. A laser beam is focused on the surface of the medium substrate 21 of the disk medium 20 by the optical laser 30 located at a predetermined position,
The amount of reflected light is measured using a device not shown. A large number of fine tracks (grooves) are provided in a spiral shape on the surface of the medium substrate 21.

For example, in the case of an optical disc of 5'k>, the track pitch is, for example, 1.6 μm. Therefore, when the disk medium 20 is rotated and irradiated with a laser beam, if the disk medium 20 is eccentric, the laser beam will cross the track and the amount of light reflected will change. Therefore, each time the laser beam crosses one track, one period of waves appears. That is, a track error signal (tracker error signal)
ror signal: T[ES] can be measured. For example, as shown in Figure 2(b), from a group of waves,
The number of tracks crossed by the laser beam when the disk medium 20 rotates half a revolution can be determined. Track pitch (e.g. 1.
6 μm) is originally known, so the amount of eccentricity can be estimated from this number of tracks. That is, in the example of FIG. 2(b),
This shows that the optical laser traversed seven tracks while the disk medium 20 rotated half a revolution.

FIGS. 3 and 4 show experimental examples.

In the experiment, first, the disk medium 20 was mounted in the normal state with the spindle 10 stationary, and then the spindle rotation was changed from the normal rotation (1800 rpm) as follows.

i) Rotate at 1800 rpm and T [ES measurement ii) 3
TBS measurement at 600 rpm 1ii) 540Qrp
m and TES measurement iv) 7200 rpm and TB
S measurement v) TBS measurement after returning to 1800 rpm Figure 3 shows the results of the first experiment, and Figure 4 shows the results of the second experiment.If the results of TεS measurement are converted into eccentricity, the obtained results are as follows. That's right.

Rotation speed 1st time i) 1800 rpm 21.6 ttmi
i) 3600 rpm 11.2 μm1ii
) 5400rpm 9.6 μm1v)
? 20Orpm 9.6 μmv) 180
0 rpm 12.0 μm 2nd time 40.0 μm 19.2 μm 17.6 μm 16.8 μm 20.0 μm As mentioned above, for both the first and second times, it was installed first and rotated normally. When rotating at a certain 1800rpm, the rotational speed is higher than normal rotation (3600rpm).
It can be seen that the amount of eccentricity is much smaller when the rotation is returned to normal rotation after rotation at 1.540 Orpm, 7200 rpm).

As mentioned above, this is done so that the rotational force of the disk medium 20 overcomes the frictional force between the disk medium 20 and the spindle 10 side due to the magnetic attraction force, and the rotational balance of the disk medium 20 is in the best condition. It is believed that the above correction was performed due to a slight slippage between the medium 20 and the spindle 10.

In the above embodiments, an optical disk medium has been described as the medium, but the present invention can also be applied to a magnetic disk medium. In addition, if an electromagnet is used as the magnet 13 for magnetic attraction and the magnetic attraction force is adjusted to weaken when correcting the eccentricity, the correlation between the magnetic attraction force and the friction force retention force will cause the rotation during high-speed rotation. Even if the number does not increase that much, the effect of the correction will be sufficient.

Further, although an embodiment of magnetically attracting and holding the disk medium has been described as a method of chucking the disk medium, the present invention is also applicable to a mechanical chucking method. Such a mechanical chucking method includes, for example, a ring-shaped collet (not shown) that is biased downward by a spring above the optical disk medium 20 instead of the magnet 13 in FIG.
The periphery of the hub 24 of the optical disk medium 20 is held between this collet and the support member 12.

〔Effect of the invention〕

As described above, according to the present invention, even if the disk medium 20 is mounted on the spindle 10 with a large amount of eccentricity, there is a slight difference between the disk medium 20 and the spindle 10 while the disk medium 20 is being rotated at a higher rotation speed than normal rotation. Slip occurs and eccentricity decreases. Therefore, there is an effect that the rotational stability of the disk medium 20 and the operation stability of the head etc. are improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of the disk medium driving method of the present invention, in which (a) is a schematic diagram, (a) is a block diagram, and (2) is a block diagram.
The figure shows a method for measuring the amount of eccentricity and correction amount of a disk medium, (a) is a schematic diagram, (b) is a waveform diagram, and Figures 3 and 4 show the rotation dependence of eccentricity. Figure 5 is a diagram showing the results of an experimental example, and Figure 5 is a diagram showing a conventional disk medium mounting procedure, in which (a) shows the disk medium, (b) shows the mounting operation, and (C
) is a plan view of the center of the disk, and FIG. 6 is a diagram showing the state after the disk medium is installed. DESCRIPTION OF SYMBOLS 10...Spindle on the apparatus main body side, 11...Main shaft, 12...Supporting member, 13...Magnet, 14...Center positioning shaft, 20...Optical disk, 21.22... - Medium substrate, 23... Medium, 24... Hub, 25... Center hole, 26... Magnetic metal, 30... Laser.

Claims (1)

[Claims] 1. In a method of driving a disk medium (20) while being held by a mechanism (10) that rotationally drives the disk medium, the mechanism (10) holds the disk medium (20) and drives the mechanism (10). (10) A method for driving a disk medium, characterized in that the disk is first rotated at high speed and then returned to a predetermined normal rotation.