JPH1097780A - Disk damper for optical disk - Google Patents

Abstract

(57) Abstract: An optical disk device, for example, a high-speed CD-ROM drive, suppresses a vibration transmitted from a spindle motor system, and reduces a load on an information reading objective lens driving device. A disk vibration suppression device 29 is provided on the upper and lower surfaces of a rotating disk 1 for suppressing vibration in the direction of surface runout, and the disk vibration suppression device 29 is disposed at a position where the vibration mode of the disk 1 is antinode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus for rotating a recording medium (disk) at a high speed by a spindle motor to record and reproduce information, such as a CD-ROM.
In particular, the present invention relates to a disk damping device for an optical disk that suppresses vibration or noise of the device itself due to surface runout of the disk.

[0002]

2. Description of the Related Art Conventional optical disks are disclosed in, for example,
No. 59-52454, in which a disk for correcting runout is fastened to a disk and both are rotated together. Alternatively, as described in Japanese Patent Application Laid-Open No. 4-254921, there is a method of measuring the runout state by a detection system mounted on a drive by itself and suppressing it by a servo system.

[0003]

In a current optical disk device, for example, a CD-ROM or the like, there is a limitation in mechanical accuracy so that the standard deviation of the upper surface of the disk is ± 500 μm and the amount of eccentricity is ± 70 μm or less. Therefore, when the worst disk (surface wobble) is used, the surface wobble of the disk due to the rotation of the disk is large, and the excitation force is transmitted to the movable optical head via the spindle motor, and unnecessary vibration is transmitted to the objective lens. There was a problem. This vibration is transmitted not only to the vibration of the objective lens but also to the chassis that fixedly supports the spindle motor and the movable optical head, and is transmitted to the outside as vibration or noise.

[0004] It is an object of the present invention to suppress such vibrations and noises caused by surface runout of a disk by a mechanism in the drive.

[0005]

According to the present invention, there is provided a spindle motor for closely fixing a disk-shaped recording medium having an information recording surface to a rotating member and rotating the medium at a high speed. Movable light comprising an objective lens provided to face the surface, an objective lens driving means for moving the objective lens in the radial direction of the medium and a direction of surface deflection due to rotation, and a head moving means for moving in the radial direction of the medium. An optical disc device comprising a head, a chassis that fixedly supports the spindle motor and the movable optical head, and one or more vibration damping members on the upper or lower surface of the information recording medium, and one or more vibration damping members on the upper and lower surfaces, respectively. It is decided to have a disk damping device for an optical disk arranged so as to float in contact or with a small gap.

The specific shape of the damping member is a roll shape of a pin insertion type. Further, a configuration in which the shape of the vibration damping member is formed in a wedge shape so as to widen the air inflow side of the gap between the recording medium surface and the vibration damping member and narrow the outflow side, and the vibration damping member is supported by an elastic member may be used. Good.

The vibration damping member is arranged at the antinode of the resonance mode of the recording medium. The vibration damping member may be arranged on the upper surface of the objective lens via the recording medium, or on the upper and lower surfaces of the recording medium, in front of or behind the position of the objective lens in the rotation direction of the recording medium.

As described above, for example, a CR-ROM
The disk for use is specified to have a surface runout of ± 500 μm or less. When a disk with a surface runout of ± 500 μm is recorded / reproduced by a drive, vibration is transmitted to the spindle motor and the chassis supporting the spindle motor due to the disk runout. You. The disk damping member according to the present invention forcibly suppresses the surface runout by bringing the damping member into contact with the upper or lower surface of the rotating disk.
In other words, by reducing the surface runout of the disk that causes vibration, the vibration excitation beyond that can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a mechanical configuration around a spindle motor 4, a disk 1, and a movable optical head 6 of a CD-ROM drive according to an embodiment. CD-ROM drive
A spindle motor 4 for rotating the disk 1 as a recording medium at high speed and information is written on the rotating disk 1. Alternatively, a finely movable moving means capable of following the surface deflection direction and the eccentric direction of the disk 1 rotating the movable part including the objective lens 5 for reading information, and the movable part including the objective lens 5 as the disk 1 It comprises a movable optical head 6 having means for moving in the radial direction, a unit mechanism composed of a chassis 7 supporting them, and a disk loading mechanism including a disk tray 3 for taking out the disk 1. In the disk loading state, the disk tray 3
Moves to guide the disk 1 to the spindle motor 4,
A disk is sandwiched between upper and lower sides of a spindle motor 4 by a clamper using magnetic attraction on a turntable (not shown), and the disk is closely fixed. In this state, the disk 1 is rotated at a high speed by the spindle motor 4 and information is written on the disk 1 by the movable optical head 6. Alternatively, the information is read. In particular, since the purpose is to reduce the vibration from the spindle motor 4 system by suppressing the surface runout of the rotating disk 1, a vibration damping member 2a as shown in the figure is provided on the disk tray. . Hereinafter, a specific configuration of the vibration damping member 2a will be described with reference to FIG.

FIG. 2 shows a specific structure of the vibration damping member 2a shown in FIG. Since the disc tray 3 is molded from a plastic material, a projection on the gate is provided so that the disc tray 3 can be fixed through the damping member rotation support shaft 8 as shown in the figure so as to be attached to the damping member 2a. A roll-shaped damping member 2 a is passed through the rotation support shaft 8, and the damping member 2 a is slightly protruded from the surface of the disc tray 3 when assembled.
The damping member 2a is made of a flexible material such as sponge, for example, and comes into contact with a pressure very weaker than the out-of-plane direction of the rotating disk 1 and can rotate in the disk circumferential direction. The frictional force on the surface of the disk 1 is minimized.

FIG. 3 further shows that the vibration damping member 2a is
An example is shown in which the contact is made in the same manner from the upper surface. The damping method from the lower surface of the disk 1 uses the configuration shown in FIGS. 1 and 2, and the damping member 2 a is supported from the upper surface of the disk 1 via a support member 9 from a mechanical base supporting a unit mechanism (not shown). And a shaft 8 that supports the vibration damping member. The shape of the vibration damping member from the upper surface of the disk 1 is also the above-described roll shape, and is configured to be rotatable via the shaft 8.

As shown in FIG. 4, the vibration mode caused by the out-of-plane direction of the rotating disk 1 is the rotational speed (1) of the disk.
Approximately 3Hz at the outer periphery of double speed to approximately 96H at the inner periphery of 12x speed
Considering z), at most one diameter node (FIG. 4 (a)),
One circular node (FIG. 4B) or two diameter nodes (FIG. 4B)
(c)). That is, in these vibration modes, it is desirable that the position of the antinode of the vibration mode be pressed by the damping member 2a. As shown in FIG. 5, the optimal arrangement of the damping member is the antinode position of the mode shown in FIG. With respect to the position of the objective lens 5 mounted on the movable optical head 6, in the case of the vibration mode with one diameter node, the line is a straight line (13 a, 13 b) connecting the center of the disk 1 and the objective lens 5, and In the case of one ring node, the outer peripheral portion of the disk (13a, 13b, 1
3c, 13d), and in the case of two diameter nodes, they are on the crosshair (13a, 13b, 13c, 13d) including on the objective lens 5. The arrangement that satisfies these three conditions is the optimum arrangement of the disk damping device according to the present invention. The above arrangement is possible on the upper surface of the disk 1, but the position of the objective lens 5 of the movable optical head 6 is not possible on the lower surface of the disk 1. in this case,
It is sufficient to hold down the periphery of the objective lens 5.

FIG. 6 shows an embodiment of another disk damping device.

Disk 1 that rotates the shape of damping member 2b
The damping member 2b is formed in a wedge shape so as to widen the air inflow side and narrow the outflow side of the gap between the vibration damping member 2b and the elastic member 14 to support the vibration damping member 2b. The principle according to this embodiment will be described with reference to FIG. An air flow is generated in the gap due to the rotation of the disk, and a pressure distribution as shown in the figure is generated from the inflow side to the outflow side of the air due to the shape of the damping member. The maximum value of this pressure occurs when the gap becomes narrowest, and this pressure causes the air spring effect to occur.
Out of the plane is forcibly suppressed.

FIG. 8 shows an embodiment of a disk damping device using the air spring effect. Wedge type vibration damping member 2b
Is a flat plate suspension (elastic member 14) as shown in the figure
The other end of the elastic member 14 is fixed to the fixing portion 16 by, for example, a set screw 15. This suspension 14 is very soft in the vertical direction and very rigid in the horizontal direction.

[0017]

By using the disk damping device for an optical disk according to the present invention, the amount of surface runout can be reduced even for a surface runout disk, and the transmission of vibration to the spindle motor can be reduced. That is, the transmission of vibration to the chassis supporting the spindle motor and the movable optical head can be reduced, so that the vibration of the apparatus itself and the noise can be reduced.
In addition, by suppressing vibration during rotation of the disk itself, the acceleration sensitivity of the lens driving means for following the target position of the disk can be reduced, so that low power consumption of the drive device or higher speed rotation is required. The conventional drive device can be applied.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a unit mechanism provided with a disk damping device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the disk damping device shown in FIG.

FIG. 3 is an explanatory view of an embodiment in which the vibration damping members according to the present invention are arranged above and below the disk.

FIG. 4 is an explanatory diagram of a vibration mode of a disk.

FIG. 5 is an explanatory diagram of an optimal arrangement of a vibration damping member according to the present invention.

FIG. 6 is an explanatory diagram of another embodiment of the disk damping device according to the present invention.

FIG. 7 is an explanatory diagram of the principle of a wedge-shaped disk damping device.

FIG. 8 is an explanatory view of one embodiment of a wedge-shaped disk vibration damping device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disc, 2a, 2b ... Damping member, 3 ... Disc tray, 4 ... Spindle motor, 5 ... Objective lens, 6 ... Movable optical head, 7 ... Chassis.

Continued on the front page. (72) Inventor Shozo Saegashi 502, Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratories, Hitachi, Ltd. Inside the laboratory (72) Inventor Hisahiro Miki 1410 Inada, Hitachinaka-shi, Ibaraki Pref., Ltd.Video and Media Division, Hitachi, Ltd. (72) Inventor Shigeki Mori 292 Yoshidacho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Media Division

Claims (1)

[Claims] A spindle motor for closely fixing a disk-shaped recording medium having an information recording surface to a rotating member and rotating at a high speed; an objective lens provided to face the information recording surface; and the objective lens A movable optical head comprising objective lens driving means for moving in the radial direction of the medium and a surface deflection direction due to rotation, and head moving means for moving in the radial direction of the medium; and fixedly supporting the spindle motor and the movable optical head. In an optical disc device constituted by a chassis, one or more vibration damping members are arranged on the upper or lower surface of the information recording medium, and one or more damping members are respectively arranged on the upper and lower surfaces so as to contact or float with a minute gap. Disc damping device for optical discs.