JPH09237443A - Optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily assemble a hub with a disk substrate and also to adapt the hub to two disk substrates stuck to each other. SOLUTION: In the optical disk 10 consisting of the disk substrate 11 in a discoid shape having a center hole 11a in the center and the hub 12 having a center hole 12a to be engaged with a motor shaft 14 of a spindle motor 13 without backlash, the hub 12 is provided with such tapered surfaces 12b and 12c by inclining its outer circumferential surface in at least one direction to its axial direction that the outermost periphery is larger than the center hole 11a of the disk substrate 11 in diameter, while the innermost periphery is smaller than the center hole 11a of the disk substrate 11 in diameter. Moreover, the hub 12 is gently engaged with the center hole 11a of the disk substrate 11 in the tapered surface area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc such as a compact disc (CD), a CD-ROM, a CD-R, a magneto-optical disc (MO), a mini disc (MD), etc., and particularly, a hub can be easily assembled. The present invention relates to an optical disc.

[0002]

2. Description of the Related Art Conventionally, such an optical disk is composed of a disk-shaped disk substrate and a hub assembled in a center hole provided at the center of the disk substrate. The hub is used for centering and chucking the optical disc with respect to a spindle motor for driving the optical disc to rotate, and the hub of the hub with respect to the center of the track formed on the disc substrate. The center holes are aligned and adjusted so that they are aligned, and then fixed.

In the optical disc having such a structure, the center hole of the hub is fitted to the motor shaft of the spindle motor of the optical disc device so that the optical disc is centered and the surface of the optical disc has the motor shaft. The optical disk is chucked by being placed on the turntable attached to the optical disk, and the hub is fixedly held on the turntable by the chucking mechanism.

[0004]

By the way, in the optical disc constructed as described above, the hub which is useful for centering the optical disc must be accurately aligned with the optical disc. Therefore, the disc substrate and the hub must be formed with high precision, and the disc substrate and the hub must be positioned with high precision. For this reason, there is a problem in that the cost is increased because an adjustment process and adjustment equipment are required in order to increase the accuracy of each component and perform the high-precision alignment of the disk substrate and the hub.

On the other hand, in a so-called mini disk (MD), which is a type of optical disk, the centering of the optical disk is performed by using the center hole of the disk substrate, and the chucking is performed by using a suction plate incorporated in the disk substrate. It is supposed to be done by using it,
With this method, in the case of a high-density recording optical disk that is expected to be adopted in the future, in the case of an optical disk in which two disk substrates are bonded together, if the center holes of the two bonded disk substrates are misaligned, centering due to the center hole will not occur. There was a problem that it would be possible.

In view of the above points, the present invention provides an optical disc in which a hub can be easily attached to a disc substrate and can be applied to, for example, an optical disc having two disc substrates bonded together. It is an object.

[0007]

According to the present invention, the above object is to provide a disc-shaped disc substrate having a center hole in the center and a disc substrate which is assembled in the center hole of the disc substrate and fitted to the motor shaft of a spindle motor. In an optical disc having a hub having a matching central hole, the outer peripheral surface of the hub is inclined toward at least one direction with respect to the axial direction, and the outermost edge of the outer peripheral surface is the center hole of the disk substrate. A taper surface having a larger diameter and a smaller inner diameter than the center hole of the disk substrate, and the hub is loosely fitted to the center hole of the disk substrate in the area of the taper surface. Is achieved by the optical disc.

According to the above construction, when the optical disk is mounted on the spindle motor of the optical disk device, the center hole of the hub is fitted to the motor shaft of the spindle motor so that the hub is centered and the hub is mounted on the spindle. It is attracted to the turntable attached to the motor shaft of the motor, and the tapered surface of the hub moves in the axial direction to come into contact with the inner surface of the center hole of the disk substrate. As a result, the disk substrate is centered with respect to the hub with the tapered surface as a reference, and the disk substrate is centered. In this case, since it is sufficient for the hub to have its tapered surface loosely fitted to the center hole of the disk substrate, it is not necessary to position the hub in alignment with the disk substrate and fix and hold it.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS.
The embodiment described below is a preferred specific example of the present invention, and thus various technically preferable limitations are added. However, the scope of the present invention particularly limits the present invention in the following description. The embodiment is not limited to these embodiments unless otherwise stated.

FIG. 1 shows a first embodiment of an optical disc according to the present invention. In FIG. 1, an optical disk 10
Is a disk-shaped disc substrate 11 having a center hole 11a in the center, and the center hole 1 of the disc substrate 11.
It is composed of a hub 12 assembled to the la 1a.

The disk substrate 11 has a signal recording surface (not shown) formed on the surface thereof and has a center hole 11a concentric with the track on the signal recording surface.

In the illustrated case, the hub 12 is entirely made of a magnetic material, and has a central hole 12a at the center thereof, into which a motor shaft of a spindle motor (described later) of an optical disk device fits with almost no play. In addition, the outer peripheral surface thereof is provided with tapered surfaces 12b and 12c that are inclined so as to expand outward in both directions with respect to the axial direction. The outermost edges (upper and lower ends in the drawing) of the tapered surfaces 12b and 12c have a diameter larger than the center hole 11a of the disk substrate 11, and the innermost edge has a diameter smaller than the center hole 11a of the disk substrate 11. Thus, it is formed concentrically with the central hole 12a. As a result, the hub 12 becomes the center hole 1 of the disc substrate 11.
1a fits loosely and the center hole 11
It is held so as to be movable with respect to a.

On the other hand, a spindle motor 13 for rotating the optical disk 10 includes a motor shaft 14 and a turntable 1 having a substantially disk shape attached to the motor shaft 14.
5 and an annular magnet 16 mounted on the turntable 15, and the turntable 15 further includes an annular disc mounting surface 15a.

The optical disc 10 according to the present embodiment is configured as described above, and the optical disc 10 is carried onto the spindle motor 13 as shown in FIG. 1 by a loading mechanism (not shown) of the optical disc device. At this time, the hub 12 is moved downward due to its own weight, and the tapered surface 12b is located at the center hole 11a of the disk substrate 11.
Is in contact with

From this state, as shown in FIG. 2, the optical disc 10 is lowered toward the spindle motor 13 by the loading mechanism. As a result, in the optical disc 10, the center hole 12a of the hub 12 is fitted to the motor shaft 14 of the spindle motor 13, and the hub 12 is centered. At this time, the hub 12 is pulled toward the lower turntable 15 not only by its own weight but also by the mutual attraction between the hub 12 made of a magnetic material and the magnet 16 on the turntable 15.

Further, as shown in FIG. 3, the optical disk 10 is lowered toward the spindle motor 13 by the loading mechanism, and the lower surface of the optical disk 10 contacts the disk mounting surface 15a of the turntable 15. At this time, the hub 12 of the optical disk 10 is pulled downward by attraction by the magnet 16, so that the upper tapered surface 12b of the hub 12 contacts the inner peripheral edge of the center hole 11a of the disk substrate 11. Therefore, the disk substrate 11 is horizontally moved on the disk mounting surface 15a so that the entire inner peripheral edge of the center hole 11a thereof contacts the tapered surface 12b of the hub 12. As a result, centering of the disk substrate 11 with respect to the motor shaft 14 of the spindle motor 13 is performed. Thus,
By mutual attraction of the hub 12 and the magnet 16, the hub 12 and the optical disk 10 are chucked with respect to the spindle motor 13, and the mounting of the optical disk 10 on the spindle motor 13 is completed.

4 and 5 show a specific example of the structure of the hub 12 described above. Since the hub 12 has the above-described shape and is integrally formed,
Since it cannot be assembled in the center hole 11a of the disk substrate 11, it is constructed as shown in FIGS. First, in FIG. 4, the hub 12 has a tapered surface 12
After being formed into two parts 12d and 12e by dividing the boundary part between b and 12c, that is, substantially from the center in the axial direction into two parts 12d and 12e, the disk substrate 11 is sandwiched from above and below, and is integrated by adhesion or the like in the center hole 11a. It has been adapted. In this case, the two parts 12d, 1
Since 2e has the same shape, the number of required parts is small and the cost is reduced.

Next, referring to FIG. 5, the hub 12 has two portions 12f and 12 which are similarly divided into upper and lower portions in the axial direction.
The extension portion 1 is made of g, and the one portion 12f extends along the central hole 12a by the entire thickness of the hub 12.
2h, the extension 12h of which is the other part 1
It is designed to be integrated by being pressed into 2 g. In this case, since the center hole 12a of the hub 12 is defined only by the one portion 12f, the spindle motor 13 can be fitted into the motor shaft 14 smoothly.

FIG. 6 shows a second embodiment of the optical disc according to the present invention. Referring to FIG.
Respectively have center holes 21a and 22a in the centers thereof, and two disc-shaped disk substrates 21 and 22 bonded to each other, and a hub 12 assembled in the center holes 21a and 22a of these disk substrates 21 and 22. It consists of and.

Each of the disk substrates 21 and 22 has a signal recording surface (not shown) formed on its surface, and a center hole 2 concentric with a track on the signal recording surface.
It has 1a and 22a. And the disk substrate 2
1 and 22 are attached to each other back to back with an adhesive or the like. Since the hub 12 has the same structure as the hub 12 in the optical disc 10 shown in FIG. 1, the description thereof will be omitted.

According to the optical disc 20 having such a configuration, the optical disc 20 is lowered toward the spindle motor 13 by the loading mechanism (not shown) of the optical disc device, as in the case shown in FIGS.
The hub 12 and the optical disk 20 are chucked to the spindle motor 13 by the mutual attraction of the magnet 2 and the magnet 16.
Installation to 3 will be completed.

Here, even when the two disk substrates 21 and 22 constituting the optical disk 20 are misaligned with each other as shown in the drawing, the upper side where signal recording or signal reproduction is attempted. Regarding the disk substrate 21,
The center hole 21 a is the tapered surface 12 of the hub 12.
By abutting on b, the centering of the disc substrate 21 is accurately performed. In this configuration, the optical pickup for recording or reproducing a signal on the optical disc 20 is shown in FIG.
Therefore, even if the optical pickup is located on the innermost peripheral side of the optical disc 20, it does not interfere with the spindle motor 13. Therefore, the spindle motor 13 may be relatively large (large diameter), and the signal recording surface of the optical disc 20 is set to a relatively large range.

FIG. 7 shows a third embodiment of the optical disk according to the present invention. In FIG. 7, an optical disc 30
Is a disc-shaped disc substrate 31 having a center hole 31a in the center, and the center hole 3 of the disc substrate 31.
It is composed of a hub 32 assembled to 1a.

The disk substrate 31 has a signal recording surface (not shown) formed on the surface thereof and has a center hole 31a concentric with the track on the signal recording surface.

In the illustrated case, the hub 32 is entirely formed of a magnetic material, and has a center hole 32a at the center thereof, into which a motor shaft of a spindle motor (described later) of an optical disk device fits with almost no play. In addition, the outer peripheral surface thereof is provided with a tapered surface 32b that is inclined so as to spread outward in one direction (upward in the case shown) with respect to the axial direction. The outermost edge (upper end in the drawing) of each of the tapered surfaces 32b has a larger diameter than the center hole 31a of the disk substrate 31, and the innermost edge (lower end in the drawing) has a smaller diameter than the center hole 31a of the disk substrate 31. Is formed concentrically with the central hole 32a.
Further, the hub 32 is provided with a retaining flange portion 32b that protrudes radially outward from the lower end thereof. As a result, the hub 32 is loosely fitted in the center hole 31a of the disc substrate 31 and is movably held in the center hole 31a.

The optical disc 30 according to this embodiment is configured as described above, and the optical disc 30 is shown in FIG. 7 by the loading mechanism (not shown) of the optical disc device.
As shown in FIG.

From this state, the optical disc 30 is lowered toward the spindle motor 13 by the loading mechanism. As a result, the center hole 32a of the hub 32 of the optical disk 30 is fitted to the motor shaft 14 of the spindle motor 13, and the hub 32 is centered.

Further, as shown in FIG. 8, the optical disc 30 is moved to the spindle motor 1 by the loading mechanism.
3, the lower surface of the optical disk 30 contacts the disk mounting surface 15a of the turntable 15. At this time, the hub 32 of the optical disk 30 is pulled downward by the attraction by the magnet 16, so that the hub 3
The second tapered surface 32b abuts on the inner peripheral edge of the center hole 31a of the disk substrate 31. Therefore, the disk substrate 31 is horizontally moved on the disk mounting surface 15a so that the entire inner peripheral edge of the center hole 31a thereof abuts the tapered surface 32b of the hub 32. As a result, centering of the disk substrate 31 with respect to the motor shaft 14 of the spindle motor 13 is performed. Thus, the hub 32 and the optical disk 30 are chucked with respect to the spindle motor 13, and the spindle motor 1 of the optical disk 30 is
Installation to 3 will be completed.

9 and 10 show a specific example of the structure of the hub 32 described above. First, referring to FIG. 9, the hub 3
After the flange portion 32c is formed separately, the reference numeral 2 is configured to be integrated by bonding or the like in the center hole 31a so as to sandwich the disc substrate 31 from above and below. Next, referring to FIG. 10, the hub 32 has a flange portion 32.
Instead of c, the projections 32d are provided at equal angular intervals in the circumferential direction. The protrusion 32d is made of an elastically deformable material, and is integrally formed with the main body of the hub 32. As a result, the hub 32
In FIG. 7, the center hole 3 is shown from above the disc substrate 31.
When inserted into 1a, each protrusion 32d passes through the center hole 31a while elastically deforming. Thus, the hub 32 can be easily assembled to the disc substrate 31.

FIG. 11 shows a fourth embodiment of the optical disc according to the present invention. In FIG. 11, the optical disc 40 has center holes 41a and 42a at the centers thereof.
And two disc-shaped disc substrates 41 and 42 bonded to each other, and a hub 43 attached to the center holes 41a and 42a of the disc substrates 41 and 42.
It is composed of

Each of the disk substrates 41 and 42 has a signal recording surface (not shown) formed on the surface thereof, and a center hole 4 concentric with a track on the signal recording surface.
It has 1a and 42a. And the disk substrate 4
1, 42 are attached to each other back to back with an adhesive or the like. Further, in the disk substrates 41 and 42, the areas of the center holes 41a and 42a are annular step portions 41.
By having b and 42b, a narrow space 44 is defined vertically in FIG.

In the illustrated case, the hub 43 is entirely formed of a magnetic material, and has a central hole 43a at the center thereof, into which a motor shaft of a spindle motor (described later) of an optical disk device fits with almost no play. In addition, the outer peripheral surface thereof is provided with tapered surfaces 43b and 43c that are inclined so as to taper in both directions with respect to the axial direction. The outermost edges (near the center in the drawing) of the tapered surfaces 43b and 43c are larger than the center holes 41a and 42a of the disk substrates 41 and 42, respectively, and the innermost edges (the upper end and the lower end in the drawing) are the above-mentioned. The disk substrates 41, 42 are formed concentrically with the center hole 43a so as to have a smaller diameter than the center holes 41a, 42a. As a result, the hub 43 is loosely fitted into the space 44 defined by the disk substrates 41 and 42, and the center holes 41a and 4 are formed.
It is movably held with respect to 2a.

According to the optical disc 40 having such a structure, the optical disc 40 is carried onto the spindle motor 13 by the loading mechanism (not shown) of the optical disc device, as shown in FIG.

From this state, as shown in FIG. 12, the optical disc 40 is lowered toward the spindle motor 13 by the loading mechanism. As a result, in the optical disc 40, the center hole 43a of the hub 43 is fitted to the motor shaft 14 of the spindle motor 13, and the hub 43 is centered.

Further, as shown in FIG. 13, the optical disk 40 is lowered toward the spindle motor 13 by the loading mechanism, and the lower surface of the optical disk 10 contacts the disk mounting surface 15a of the turntable 15.
At this time, the hub 43 of the optical disc 40 is moved to the magnet 16
The taper surface 43c on the lower side of the hub 43 is pulled downward by suction by the disk substrate 4
It abuts on the inner peripheral edge of the second center hole 42a. Therefore, the disk substrate 42 is horizontally moved on the disk mounting surface 15a such that the entire inner peripheral edge of the center hole 42a thereof contacts the tapered surface 43c of the hub 43. As a result, centering of the disk substrate 42 with respect to the motor shaft 14 of the spindle motor 13 is performed. Thus, the hub 43 and the optical disc 40 are chucked to the spindle motor 13 by the mutual attraction of the hub 43 and the magnet 16, and the mounting of the optical disc 40 on the spindle motor 13 is completed.

Here, even when the two disc substrates 41 and 42 constituting the optical disc 40 are misaligned with each other, the center hole of the lower disc substrate 42 for signal recording or signal reproduction is to be formed. 42a
By contacting the tapered surface 43c of the hub 43,
The disc substrate 42 is accurately centered.

As described above, in the above embodiment, when the optical disk is mounted on the spindle motor of the optical disk device, the hub is centered by fitting the center hole of the hub into the motor shaft of the spindle motor. , The hub is attracted to the turntable attached to the motor shaft of the spindle motor, so that the taper surface of the hub moves in the axial direction and abuts the inner surface of the center hole of the disk substrate, so that the disk substrate is attached to the hub. The center of the disk substrate is centered by using the tapered surface as a reference.

Therefore, in order to align the hub with the disk substrate with high accuracy, the hub and the disk substrate are formed with high accuracy, and the hub is positioned and adjusted with high accuracy with respect to the disk substrate and fixed. Since there is no need, the component cost and the assembly cost are reduced, and the cost reduction of the optical disc is easily realized. Further, in the case of an optical disc in which two disc substrates are bonded together, even if the two disc substrates are misaligned with each other, each disc substrate is accurately centered by one hub.

In the above embodiment, the hub 12,
Each of 32 and 43 is entirely made of a magnetic material, but the invention is not limited to this. It is sufficient if mutual attraction force is generated between the hub and the turntable 15 of the optical disk device. May be made of a magnetic material, or conversely, all or part of the hubs 12, 32, 43 may be made of a magnet, and instead of the magnet 16, a magnetic material such as an iron plate is provided on the turntable 15. Obviously, may be provided.

[0040]

As described above, according to the present invention, an optical disc can be easily assembled to a disc substrate and adapted to an optical disc having two disc substrates bonded together. Will be provided.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a state before an optical disc according to a first embodiment of the present invention is mounted on a spindle motor.

FIG. 2 is a schematic cross-sectional view showing a centering state of the optical disc of FIG. 1 with respect to a spindle motor.

FIG. 3 is a schematic cross-sectional view showing a mounting state of the optical disc of FIG. 1 on a spindle motor.

4 is a cross-sectional view showing a first specific configuration example of a hub in the optical disc of FIG.

5 is a cross-sectional view showing a second specific configuration example of the hub in the optical disc of FIG.

FIG. 6 is a schematic cross-sectional view showing how an optical disc according to the present invention is mounted on a spindle motor according to a second embodiment.

FIG. 7 is a schematic cross-sectional view showing a state before the optical disc according to the present invention is mounted on the spindle motor of the third embodiment.

8 is a schematic cross-sectional view showing how the optical disc of FIG. 7 is mounted on a spindle motor.

9 is a cross-sectional view showing a first specific configuration example of a hub in the optical disc of FIG.

10 is a cross-sectional view showing a second specific configuration example of the hub in the optical disc of FIG.

FIG. 11 is a schematic sectional view showing a state before the optical disc according to the present invention is mounted on the spindle motor of the fourth embodiment.

12 is a schematic cross-sectional view showing a centering state of the optical disc of FIG. 11 with respect to a spindle motor.

13 is a schematic cross-sectional view showing a mounting state of the optical disc of FIG. 11 on a spindle motor.

[Explanation of symbols]

10 ... Optical disc, 11 ... Disc substrate, 11
a ... center hall, 12 ... hub, 12a ...
・ Center hole, 12b, 12c ... Tapered surface, 13 ...
Spindle motor, 14 ... Motor shaft, 15 ... Turntable, 16 ... Magnet, 20 ... Optical disk, 21, 22 ... Disk substrate, 21a, 22
a ... Center hall, 30 ... Optical disk, 31
... Disk substrate, 31a ... Center hole, 3
2 ... Hub, 32a ... Center hole, 32b ... Tapered surface, 32c ... Flange portion, 32d ... Protrusion, 4
0 ... Optical disc, 41, 42 ... Disc substrate,
41a, 42a ... Center hall, 41b, 42b
... Steps, 43 ... Hubs, 43a ... Center holes, 4
3b, 43c ... tapered surface, 44 ... space.

Claims (5)

[Claims] 1. An optical disc comprising a disc-shaped disc substrate having a center hole in the center and a hub assembled in the center hole of the disc substrate and having a center hole fitted to the motor shaft of a spindle motor. The outer peripheral surface of the hub is inclined toward at least one direction with respect to the axial direction, and the outermost edge of the outer peripheral surface has a diameter larger than the center hole of the disc substrate, and the innermost edge of the hub is the disc substrate. An optical disc comprising a tapered surface having a diameter smaller than that of the center hole, and the hub is loosely fitted to the center hole of the disk substrate in the region of the tapered surface. 2. The optical disc according to claim 1, wherein a part or the whole of the hub is made of a magnetic material. 3. The hub, wherein a part or the whole of the hub is made of a magnet.
An optical disk according to claim 1. 4. Two disk-shaped disk substrates having a center hole in the center and bonded to each other, and the hub has an outer peripheral surface inclined in at least one direction with respect to the axial direction. Moreover, the outermost edge of the outer peripheral surface is a tapered surface having a diameter larger than that of the center hole of the disk substrate, and the innermost edge is a diameter smaller than that of the center hole of the disk substrate, and the hub is a region of the tapered surface. The optical disc is loosely fitted in the center hole of the disc substrate. 5. The hub is housed in a space formed between two disk substrates, and the tapered surface of the hub is tapered toward the both sides from the outermost center edge in the axial direction. The optical disc according to claim 4, wherein the optical disc is formed on the optical disc.