JP3008502B2 - Optical disk and optical disk chucking mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk used as a recording medium for information signals and an optical disk chucking mechanism used for an optical disk recording and / or reproducing apparatus for chucking the optical disk.

[0002]

2. Description of the Related Art Hitherto, optical disks have been used as recording media for information signals. As shown in FIG. 2, this optical disc is configured by providing a signal recording layer 102 on one main surface of a disc-shaped disc substrate 101 made of a transparent resin such as polycarbonate, glass, or the like.

In an optical disk exclusively for reading information signals, a pit pattern composed of minute unevenness corresponding to the information signal is formed on one main surface serving as a signal recording surface 102a, and aluminum or the like is formed on the pit pattern. The signal recording layer 102 is formed by providing a reflection film made of a metal thin film. In a magneto-optical disk capable of re-recording an information signal, a signal recording layer 102 is formed by providing a thin film made of a magnetic material and a reflective film made of a metal thin film on a signal recording surface 102a. On the signal recording surface 102a, recording grooves forming recording tracks substantially concentrically or spirally are formed.

[0004] At the center of the disk substrate 101, a disk hub 103 is mounted. Disc hub 10
Numeral 3 is formed in a substantially disc shape from a magnetic material, is fitted in a hub mounting hole 101a formed in the center of the disk substrate 101, and is joined to the disk substrate 101 by an adhesive. A center shaft engaging hole 110 is formed in the center of the disk hub 103.

[0005] An optical disk recording and / or reproducing apparatus using such an optical disk as a recording medium includes a disk rotation drive mechanism for holding and rotating the optical disk, and a light beam for the optical disk rotated and operated by the rotation drive mechanism. And an optical pickup device for irradiating light.
The disk rotation drive mechanism provided in the optical disk recording and / or reproducing apparatus has a chucking mechanism for chucking the optical disk. This chucking mechanism is, as shown in FIG. 2, a spindle shaft 1 of a spindle motor 104 constituting a disk rotation drive mechanism.
04a and a disk table 105 attached to the spindle shaft 104a. The disk table 105 is formed in a substantially disc shape, and has a support hole 109 in the center on the lower surface side in which the spindle shaft 104a is fitted. The disk table 105 has a support hole 109.
The spindle shaft 104a is fitted onto the spindle shaft 104a by being fitted to the lower surface side.

[0006] A peripheral edge of the upper surface of the disk table 105 is formed as an annular disk mounting portion 106. The disk mounting portion 106 supports the optical disk and supports the optical disk at the height position of the optical disk, that is, the disk substrate 1.
01 is positioned in the direction perpendicular to the main surface. Also,
A central shaft 107 protrudes from the center of the upper surface of the disk table 105. The center shaft 107 protrudes above the disk mounting portion 106. An annular magnet 108 is provided around a central shaft 107 on the inner peripheral side of the disk mounting portion 106. The magnet 108 is provided so as not to protrude above the disk mounting portion 106.

In order to chuck the optical disk with the chucking mechanism constructed as described above, the center shaft engaging hole 11 is used.
The central shaft 107 is engaged with the disk hub 103 and the disk hub 103 is placed on the disk table 105. Then, the disc hub 103 is attracted to the disc hub 103 by the magnet 108, and the periphery of the disc hub 103 is moved to the disc mounting section 1.
06, the height position is determined with reference to the disk mounting portion 106, the centering is performed with reference to the central axis 107, and the disk is chucked on the disk table 105.

[0008]

By the way, when the optical disk chucked by the chucking mechanism is rotated, the center of curvature of the recording groove formed on the disk substrate 101 is adjusted to the spindle axis 1 of the spindle motor 104.
If the recording groove is eccentric with respect to the rotation center of the optical disk 04a, the recording groove is periodically displaced in the radial direction of the optical disk. If the amount of displacement of the recording groove is large, it becomes difficult to irradiate the optical beam along the recording groove by the optical pickup device, and it becomes impossible to accurately record and read information signals.

In the above-described optical disk chucking mechanism, the positioning of the optical disk in the horizontal direction is performed by the engagement between the central shaft 107 and the central shaft engaging hole 110. When mounting the recording groove, it is necessary that the center of the center shaft engaging hole 110 and the center of curvature of the recording groove exactly coincide with each other.

Therefore, it is necessary to position the disk hub 103 with high precision with reference to the center of the recording groove and to attach the disk hub 103 to the disk substrate 101, which makes it difficult to manufacture an optical disk.

Accordingly, the present invention has been proposed in view of the above-mentioned circumstances, and is an optical disk which can be easily manufactured and whose mounting position can be accurately positioned by using a chucking mechanism. It is an object of the present invention to provide an optical disk chucking mechanism which can be positioned and chucked.

[0012]

In order to solve the above problems and achieve the above object, an optical disk according to the present invention comprises: a disk-shaped disk substrate provided with a signal recording layer; A central hole centered on the center of curvature of a recording groove formed in the signal recording layer, and a plate made of a magnetic material attached to one main surface of the disk substrate so as to cover the central hole. And the inner peripheral surface of the center hole of the disk substrate is used as a centering reference.

The optical disk chucking mechanism according to the present invention supports the other main surface of the disk on which a center hole is provided and a plate made of a magnetic material covering the center hole is mounted on one main surface. An annular mounting portion for positioning the height position of the disk; and A tapered portion for centering, disposed on the inner peripheral side of the tapered portion,
And a magnet for attracting the plate.

[0014]

In the optical disk according to the present invention, the plate attached to one main surface of the disk substrate is attracted to the magnet, so that the other main surface is supported by the mounting portion of the chucking mechanism, and the height position is increased. Is positioned, and the taper portion of the chucking mechanism is brought into contact with the peripheral edge on the other main surface side of the center hole to achieve centering.

[0015]

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

In the optical disk according to the present invention, as shown in FIG. 1, a signal recording layer 2 is provided on one main surface of a disk-shaped disk substrate 1 made of a transparent resin such as polycarbonate, glass, or the like. It is configured. Signal recording layer 2
Are formed by providing a thin film made of a magnetic material and a reflective film made of a metal thin film on the signal recording surface 2a. On the signal recording surface 2a, recording grooves forming recording tracks substantially concentrically or spirally are formed. In the case of an optical disk dedicated to reading information signals, a pit pattern composed of minute irregularities corresponding to the information signal is formed on one main surface serving as the signal recording surface 2a, and a metal thin film such as aluminum is formed on the pit pattern. The signal recording layer 2 is formed by providing a reflection film made of

At the center of the disk substrate 1, a circular center hole 1a having a constant diameter is provided so as to penetrate from one main surface to the other main surface. The center hole 1a is formed when the disk substrate 1 is formed by, for example, injection molding. The center hole 1a is formed such that the center coincides with the center of curvature of the recording groove formed on the disk substrate 1. In order to make the center of the center hole 1a coincide with the curvature center of the recording groove, the recording groove may be formed at the same time when the disk substrate 1 is formed. That is, when the disk substrate 1 is formed by injection molding, the center of the center hole 1a and the center of curvature of the recording groove are made to coincide with each other depending on the accuracy of the mold for forming the disk substrate 1. When the recording groove is formed after the molding of the disk substrate, the recording groove may be formed with reference to the center hole 1a.

A plate 3 is attached to one main surface of the disk substrate 1 so as to cover the center hole 1a. The plate 3 is made of a magnetic material such as iron or stainless steel and has a disk shape slightly larger in diameter than the center hole 1a. Plate 3
Are bonded to the disk substrate 1 using an adhesive or the like.

The signal recording layer 2 may be interposed between the plate 3 and the disk substrate 1. Further, the signal recording layer 2 is not formed in a portion of the disk substrate 1 where the plate 3 contacts, so that these plate 3 and the disk substrate 1 are not formed.
And may directly contact with each other.

The chucking mechanism for chucking an optical disk configured as described above is applied to a disk rotation drive mechanism of an optical disk recording and / or reproducing apparatus using the optical disk as a recording medium.

This optical disk recording and / or reproducing apparatus comprises: a disk rotation drive mechanism having a chucking mechanism for chucking an optical disk; and an optical pickup for irradiating a light beam to the optical disk rotated by the rotation drive mechanism. It has a device and the like. In this optical disk recording and / or reproducing apparatus, a light beam emitted from the optical pickup device is applied to the optical disk so as to be focused on the signal recording layer 2 from the other main surface of the disk substrate 1. By scanning the recording groove with the light beam, the recording of the information signal or the reading of the recorded information signal is performed.

As shown in FIG. 1, the chucking mechanism for chucking the optical disk includes a spindle shaft 4 of a spindle motor 4 constituting a disk rotation drive mechanism.
a and a disk table 5 attached to the spindle shaft 4a. The disk table 5 is formed in a substantially disk shape, and has a support hole 9 in the center portion into which the spindle shaft 4a is fitted. That is, in the disk table 5, the spindle shaft 4a is pressed into the support hole 9 from the lower surface side and attached to the spindle shaft 4a.

The periphery of the upper surface of the disk table 5 forms a flat annular optical disk mounting portion 6. The mounting portion 6 is a disk substrate 1 of an optical disk.
To support the height position of the optical disk, that is, the position in the direction perpendicular to the main surface of the disk substrate 1. Further, a tapered portion 7 for centering the optical disk is provided on the inner peripheral side of the mounting portion 6 on the upper surface side of the disk table 5. The tapered portion 7 is formed so as to protrude above the mounting portion 6, and is gradually reduced in diameter from the base end side, which is the lower side, to the distal end side, which is higher than the base end side. . An annular magnet 8 is provided around the outer periphery of the support hole 9 on the inner peripheral side of the tapered portion 7.
The magnet 8 is provided so as not to protrude above the tip of the tapered portion 7.

In order to chuck the optical disk with the chucking mechanism configured as described above, the disk substrate 1 is placed on the disk table 5 so that the tapered portion 7 is inserted into the center hole 1a. Then, the plate body 3 is attracted by the magnet 8, and the peripheral portion of the center hole 1 a on the other main surface side of the disk substrate 1 is pressed and supported by the mounting portion 6.
At this time, the tapered portion 7 is in contact with the peripheral edge on the other main surface side of the center hole 1a. The tip of the tapered portion 7 and the upper end surface of the magnet 8 are opposed to the plate 3 with a slight gap.

In the optical disk held by the chucking mechanism as described above, the disk substrate 1 is supported by the mounting portion 6, the mounting height position is determined, and the center hole 1a is formed in the tapered portion 7.
The radial position of the disk substrate 1 is regulated by the contact of the peripheral edge on the other main surface side. Therefore, the mounting height position of the optical disk is determined with reference to the disk substrate 1 irrespective of the mounting position of the plate 3 with respect to the disk substrate 1, and the centering of the rotation of the disk table at the rotation center of the disk table is achieved.

The optical disk held by the chucking mechanism is rotated integrally with the disk table 5 by the rotation of the spindle motor 4. Then, the optical disk is irradiated with a light beam by the optical pickup device to record or read information signals.

[0027]

As described above, in the optical disk according to the present invention, the plate attached to one main surface of the disk substrate is attracted to the magnet, so that the other side of the disk substrate is placed on the mounting portion of the chucking mechanism. The main surface of the disk substrate is supported, the mounting height position is determined, and centering is achieved by contacting the peripheral portion of the center hole provided in the center portion of the disk substrate on the other main surface side with the tapered portion of the chucking mechanism. Therefore, the mounting position on the disk rotation drive mechanism can be determined based on the disk substrate regardless of the mounting position of the plate on the disk substrate. Therefore,
Since the positioning accuracy of the mounting position can be guaranteed by the processing accuracy of the disk substrate, the manufacture of the optical disk becomes easy.

In the optical disk chucking mechanism according to the present invention, the optical disk is supported by supporting the main surface of the disk substrate and bringing the center hole formed in the disk substrate into contact with the periphery of the tapered portion. The mounting height position and centering of the optical disk can be achieved with high accuracy.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an optical disk and an optical disk chucking mechanism according to the present invention.

FIG. 2 is a longitudinal sectional view showing a conventional optical disk and an optical disk chucking mechanism.

[Explanation of symbols]

Reference Signs List 1 disk substrate, 1a center hole, 2 signal recording layer, 3 plate, 6 mounting portion, 7 tapered portion, 8
magnet.

Claims (2)

(57) [Claims] A disc-shaped disk substrate provided with a signal recording layer; a central hole provided at a central portion of the disk substrate and centered on a curvature center of a recording groove formed in the signal recording layer; One main surface of the disk substrate covers the center hole.
And a plate member made of a magnetic material attached to the inner circumferential surface of the center hole of the disc substrate centering reference
And it is composed of an optical disc. 2. A center hole is provided and one main surface is provided.
A plate made of a magnetic material covering the center hole is attached to the
Support the other main surface of the disc to be
An annular mounting part for positioning the mounting position, and an inner mounting part provided on the inner peripheral side of the mounting part,
Abuts the periphery of the other main surface of the center hole
An optical disc chucking mechanism, comprising: a tapered portion for centering a workpiece ; and a magnet disposed on an inner peripheral side of the tapered portion for attracting the plate.