JPH0644356B2 - Light disk - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical disk, and more particularly to an optical disk having a structure in which two disk substrates are provided so as to face each other.

[Conventional technology]

FIG. 13 is a sectional view of a double-sided recording type optical disc manufactured by a conventional technique. As shown in the figure, two disks 53 are fixed so as to face each other via a hub 51 and an outer peripheral spacer 52. This disk 53
It is composed of a transparent disk substrate 54 and a recording film 55 provided on one surface thereof, and a pregroup 56 is formed concentrically on the recording film 55, and the two disks 53 are arranged between the recording films 55. It is arranged to face each other.

On the other hand, the hub 51 is made of a material having wear resistance such as metal, and a spindle (not shown) of a drive device is inserted in the center of the hub 51 to position the optical disk in the device. A center hole 57 is provided for this purpose. In the figure, 58 is two disks 5.
It is an air gap formed between the three.

14 to 16 are explanatory views showing the manufacturing process of the optical disk, and the conventional manufacturing method will be described with reference to these drawings.

First, as shown in FIG. 15, the pregroup 5 is formed on the surface.
6 on the stamper 60 having a large number of concentric grooves 59 corresponding to No. 6 and an uncured ultraviolet curable resin 61.
Is dripped. Then, the disk substrate 54 is pressed onto the resin 61 in a state in which the disk substrate 54 is slightly curved so that the central portion thereof faces downward, and the peripheral portion is gradually lowered onto the stamper 60. When the disk substrate 54 is pressed against the stamper 60 in this manner, the ultraviolet curable resin 61 can be pushed and expanded in the outer peripheral direction without containing air bubbles between them, and the grooves 59 are also filled.

Then, as shown by the arrow in FIG. 15, the disk substrate 5
Ultraviolet ray 62 is irradiated from above the ultraviolet ray 4 to cure the ultraviolet ray curable resin 6
1 is cured. Next, the disk substrate 54 is attached to the stamper 6
When peeled off from 0, the cured resin film also remains on the disk substrate 54.
At the same time, the replica film 55 is separated from the stamper 60, thereby forming the pre-group 56. After the replica process is completed in this way, a recording film is deposited on the surface of the replica film 55.

Next, the disk substrate 54 is formed by using the pre-group 56.
By optically determining the center position of the disk, and forming a central through hole 63 in the disk substrate 54 on the basis of the central position, and adhering the hub 51 and the outer peripheral spacer 52 to these and combining them, the thirteenth
An optical disk as shown in the figure is produced.

However, this conventional manufacturing method has a drawback in that it is difficult to align the sensor when the disk substrate 54 and the hub 51 are combined, there is a problem in reliability, and productivity is poor.

That is, since the disk substrate 54 needs to be transparent for writing and reading information, polycarbonate resin, epoxy resin, glass or the like is used, for example. On the other hand, the hub 51 is required to have wear resistance because the optical disk is repeatedly attached to and detached from the disk drive device, and metal is generally used. As described above, the disk substrate 54 made of synthetic resin or glass and the metal hub 51 have a large difference in thermal expansion coefficient in the order of 10 times, and therefore the disk substrate 54 is not deformed by the thermal expansion of the hub 51. In order to do so, a slight clearance is provided in the fitting portion between the disk substrate 54 and the hub 51. This clearance is also necessary to facilitate the fitting between the disk substrate 54 and the hub 51. With such a clearance, a relative positional deviation, that is, a center deviation is likely to occur when the disk substrate 54 and the hub 51 are assembled.

In this way, the disk substrate 54 remains with the center deviation.
When the hub 51 and the hub 51 are adhered to each other, when the hub 51 is attached to the disk drive device for writing or reading,
As described above, the optical disk is positioned in the device by fitting the hub 51 to the spindle.
Since the pregroup 56 on the recording film 55 is eccentrically rotated with respect to the rotation center of the optical disk, accurate tracking cannot be performed, and there is a problem in reliability. Especially recently, the pitch of the pre-group 56 is 1.
Since it is extremely small, about 6 μm, the influence of the above-mentioned track deviation appears directly on the characteristics.

In order to prevent this from happening, when the disk substrate 54 and the hub 51 are bonded together, the positional relationship between the two is done one by one while observing them with a microscope. It had drawbacks such as very poor productivity.

In order to solve this drawback, the present applicant previously bonded the first hub provided with the inner flange portion to the central portion of the first disk substrate on which the recording film having the pregroup is not formed,
A second hub provided with an inner brim is adhered to a central portion of a second disk substrate having no recording film having a pregroup, and each of the disc substrates is pre-printed on the basis of the central portion of these hubs. A method of manufacturing an optical disk provided with a recording film having groups has been proposed.

If the optical disk is manufactured by such a method, the center of each hub and the center of the pre-group always coincide with each other, so that it is not necessary to perform the troublesome center alignment as in the conventional case, and the off-track due to the center deviation is eliminated and the reliability is improved. You can get a high optical disc. However, this optical disk is not without its drawbacks.

[Problems to be solved by the invention]

That is, as the optical disk becomes thinner, the adhesive strength between the disk substrate and the hub becomes insufficient, and the disk substrate and the hub separate when mounted on the disk drive device, resulting in a defective product.

This will be specifically described as follows. That is, as the optical disk becomes thinner, the distance between the two disk substrates becomes narrower, and the thickness of the flange portion of the hub becomes thinner. For example, when using a disk substrate with a thickness of 1 mm to manufacture an optical disk with a total height of 2.8 mm and an outer diameter of 300 mm, the thickness of the flange on the hub is 0.25 to 0.30 mm.
It has to be about. When the collar becomes thin in this way, the radial length of the collar is limited from the viewpoint of mechanical strength, and if the thickness of the collar is about 0.25 to 0.30 mm as described above, the collar radial direction is limited. The length can be increased by at most 3mm. From the above, especially when the optical disk becomes thin, the length of the flange portion of the hub becomes short, and accordingly, the bonding area between the disk substrate and the hub becomes narrow, and thus the joint portion between the both easily separates.

The object of the present invention is to eliminate such drawbacks of the prior art,
Even if the optical disk becomes thinner, the optical disk is surely adhered to the disk substrate and the hub, which is the disk supporter, and has high operation reliability.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention secures a first disk support, such as a hub, having an inner collar portion to the central portion of a first disk substrate with an adhesive, and a first disc support having an inner collar portion, such as a hub. A two-disk support is fixed to the center of the second disk substrate with an adhesive, and the first disk substrate is arranged so that the inner flange of the first disk support and the inner flange of the second disk support face each other. And an second disc substrate, an inner disc spacer is disposed on the outer periphery of the inner flange of the first and second disc supports, and the inner and outer spacers are disposed between the inner disc spacer and the disc substrate. The peripheral spacer and the inner brim are integrally connected by an adhesive.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings. First
FIG. 1 is a sectional view of a double-sided recording type optical disk according to the first embodiment,
FIG. 2 is an enlarged plan view of the hub used for the optical disc in a state where the adhesive is applied, FIG. 3 is a sectional view taken along the line AA in FIG. 2, and FIG. 4 is a peripheral spacer used for the optical disc. A plan view, FIGS. 5 to 11 are views for explaining a manufacturing process of the optical disk, and FIG. 12 is an enlarged sectional view of an essential part of the optical disk.

As shown in FIG. 1, in the case of this optical disc, two first discs 3 and two discs 4 are fixed so as to face each other via an inner peripheral spacer 1 and an outer peripheral spacer 2. The first disk 3 is a transparent first disk substrate 5
And a first recording film 6 provided on one side thereof, and a concentric circular or spiral first pregroup 7 is formed on the first recording film 6 (see FIG. 12).
Similarly, the second disk 4 is also composed of a transparent second disk substrate 8 and a second recording film 9 provided on one side thereof, and the second recording film 9 has a concentric circular or spiral shape. Two pre-groups 10 are formed (see FIG. 12). The two disks 3, 4 are arranged such that the recording films 6, 9 face each other.

A first hub 11 is provided at the center of the first disk substrate 5,
Second hubs 12 are integrally bonded to the central portion of the second disk substrate 8. These hubs 11, 12
Is made of a wear-resistant and magnetic metal such as an iron-nickel-chromium alloy containing 42 wt% nickel and 6 wt% chromium. Hub 11
As shown in FIGS. 2 and 3, (12) is composed of a cylindrical portion 14 having a center hole 13 and an inner brim portion 15 and its side surface is substantially gear-shaped. Made by processing.

As shown in FIG. 2, the flange portion 15 is not provided continuously over the entire circumference, but a plurality of (six in the case of this embodiment) inner portions at equal intervals in the circumferential direction. Then, the arc-shaped notch 16 is formed to be intermittent. Further, following the tip of the notch 16, the cylindrical portion 14
A gas vent groove 17 is vertically provided on the outer peripheral surface of the cylindrical portion 14 from the lower end to the upper end. In addition, 18 in the figure
Is an annular adhesive agent reservoir formed on the end surface of the inner flange portion 15, and the adhesive agent reservoir 18 may be omitted in other drawings. As shown in FIG. 12, the outer peripheral edge and the inner peripheral edge of the cylindrical portion 14 are chamfered.

FIG. 4 is a plan view of the outer peripheral spacer 2. The outer peripheral spacer 2 and the inner peripheral spacer 1 are made of, for example, metal such as stainless steel or aluminum, ceramics, or synthetic resin such as epoxy resin or polycarbonate resin. On the upper surface of the outer peripheral spacer 2, as shown in the figure, one or a plurality of gas vent grooves 19 (one in this embodiment) are formed penetrating from the inside to the outside.

Next, the manufacturing process of this optical disk will be described with reference to FIGS.

First, as shown in FIG. 5, a center hole 13 is provided in the central portion of the hub 11 (12) with high processing accuracy, while the disk substrate 5 on which the recording film 6 (9) is not formed is formed.
The through hole 20 is provided at the center of (8). Then, as shown in the figure, the ultraviolet curable adhesive 21 is applied to the upper surface of the inner flange portion 15 of the hub 11 (12), and the cylindrical portion 14 is inserted into the through hole 20 of the disk substrate 5 (8), The hub 11 (12) and the disk substrate 5 (8) are integrally bonded by irradiating the bonding portion with ultraviolet rays.

As shown in FIG. 2, the adhesive 21 is applied in a strip shape on the substantially central portion of the collar portion 15. Therefore, when the collar portion 15 and the inner peripheral portion of the disk substrate 5 (8) are overlapped with each other, the adhesive is adhered. Most of the agent 21 spreads over almost the entire surface of the collar portion 15, and if there is excess adhesive agent, it flows into the cutout portion 16 provided in the collar portion 15.

Next, the disk substrate 5 (8) with a hub is pressed onto the stamper 22 as shown in FIG. 6, and the upper surface of the stamper 22 has a concentric shape corresponding to the pregroup 7 (10) or A spiral groove 23 is formed,
A positioning pin 24 is provided at the center of the groove 23,
A predetermined amount of uncured and fluid ultraviolet curable resin 25 is dropped on the stamper 22.

As shown in the same figure, the stamper 22 is formed by slightly bending the disk substrate 5 (8) so that the central portion thereof faces downward.
It is lowered and the positioning pin 24 is inserted into the center hole 13 of the hub 11 (12). As a result, the position of the disk substrate 5 (8) on the stamper 22 is correctly determined. When the disk substrate 5 (8) is pressed against the stamper 22 side in this state, the ultraviolet curing resin 2
5 is gradually expanded toward the outer circumference without containing air bubbles,
The uncured resin 25 also flows into and fills the grooves 23.

Thereafter, as shown in FIG. 7, in a state where the disk substrate 5 (8) is completely pressed against the stamper 22, ultraviolet rays 26 are evenly irradiated from above to cure the ultraviolet curing resin 25. Next, the disk substrate 5 (8) is attached to the stamper 2
When peeled from 2, the hardened resin film also remains on the disk substrate 5.
The replica film 6 (9) separated from the stamper 22 along with (8), and thereby formed the pregroup 7 (10).
Becomes

After the replica process is completed in this way, two discs 3 and 4 on which a recording film is vapor-deposited are prepared in the next process, and one of the second discs 4 is placed on the base 27 as shown in FIG. Centering hole 2 placed on the upper surface of the base 27
By inserting the center hole 13 of the second hub 12 into 8, the second disk 4 is positioned on the base 27.

Then, the epoxy adhesive 29 is applied to the outside of the adhesive reservoir 18 of the second hub 12. Further, the epoxy adhesive 29 is similarly applied to the entire upper and lower surfaces of the inner peripheral spacer 1 and the outer peripheral spacer 2. When the adhesive 29 is applied to the outer peripheral spacer 2, the wire material 30 is previously fitted into the gas vent groove 19 (see FIG. 4) provided on the upper surface thereof as shown in FIG. 9, and then the adhesive 29 is applied. This prevents the adhesive 29 from flowing into the gas vent groove 19.

The inner peripheral spacers 1 and the outer peripheral spacers 2 thus coated with the adhesive 29 are placed at predetermined positions on the disk 4. FIG. 10 shows this state, and the second hub 1
The inner peripheral spacer 1 can be centered by bringing the tip of the inner flange portion 15 at 2 into contact with the inner peripheral surface of the inner peripheral spacer 1.

After that, the first disk 3 having the epoxy adhesive 29 applied to the outer peripheral portion of the adhesive reservoir 18 on the lower surface of the first hub 11 is placed on the inner peripheral spacer 1 and the outer peripheral spacer 2, and the disk 3 The center hole 13 of the first hub 1 is inserted into the centering pole 28.
As a result, the first disk 3 and the second disk 4 are centered at correct positions, and when the adhesive 29 is slightly dried and loses its fluidity, the wire rod 30 of the outer peripheral spacer 2 is pulled out, and FIG. Peripheral spacer 2 as shown in
The gas vent groove 19 is opened.

In this state, the adhesive 29 is cured, the gas generated at that time is discharged to the outside through the gas vent groove 19, and the two disks 3, 4 and the inner peripheral spacer 1 and the outer peripheral spacer 2 are bonded together. Thereafter, as shown in FIG. 1, the opening of the gas vent groove 19 of the outer peripheral spacer 2 is closed with a sealant 31 such as an epoxy adhesive to complete the optical disc assembly.

The optical disc assembled in this way is bonded to the adhesive 29.
The gas generated at the time of curing does not remain inside, and the degassing groove 19 is closed so that water vapor or the like does not enter from the outside. Therefore, the alteration of the recording film 6 (9) due to the gas or water vapor is eliminated. .

When joining the first hub 11 and the second hub 12, the adhesive 29 applied to the first hub 11 and the second hub 12 is filled in the gap between the hubs 11 and 12, and the excess adhesive 29 is applied to the center hole 13 side. Although it advances, there is an adhesive reservoir 18 in the middle, so that it will not be retained in the adhesive reservoir 18 and protrude to the inner peripheral surface of the center hole 13 (see FIG. 12). If the adhesive 29 squeezes out and hardens, the optical disk and the spindle of the disk drive device will not fit well or the tracking performance of the optical disk will deteriorate.

Further, when the inner peripheral spacer 1 and the disk substrate 5 (8) are bonded with the adhesive 29, the pre-existing adhesive 29 protrudes from between the inner peripheral spacer 1 and the disk substrate 5 (8), and the inner peripheral spacer 1 and It flows into a space between the inner flange portion 15 of the hub 11 (12) and adheres the inner peripheral spacer 1 to the hubs 11 and 12. In addition, even if there is a surplus of adhesive at this time,
A notch 16 is provided between the inner peripheral spacer 1 and the hub 11 (12).
Since a gap (see FIG. 10) is formed by
The preliminary adhesive is stored in the gap.

〔The invention's effect〕

As described above, the present invention arranges the inner peripheral spacers between the disk substrates and on the outer periphery of the disk support so that the space between the disk substrate and the disk support, the space between the disk substrate and the inner spacer, and the disk support. The body and the inner peripheral spacer are integrally bonded with an adhesive. Therefore, since the adhesive strength between the disk substrate and the disk support can be reinforced by the adhesion of the inner peripheral spacer, even if the optical disk becomes thin and the adhesive area between the disk substrate and the disk support becomes narrow, the operation reliability is improved. A high optical disc can be provided.

[Brief description of drawings]

1 is a sectional view of an optical disk according to a first embodiment of the present invention, FIG. 2 is an enlarged plan view of a hub used in the optical disk in a state where an adhesive is applied, and FIG. FIG. 4 is a cross-sectional view taken along the line AA, FIG. 4 is a plan view of an outer peripheral spacer used for the optical disk, FIG. 5, FIG. 6, FIG. 7, FIG.
FIGS. 10, 10 and 11 are explanatory views for explaining the manufacturing process of the optical disc, FIG. 12 is a partially enlarged sectional view of the optical disc, and FIG. 13 is a sectional view of a conventional optical disc, FIG. 14, FIG. 15 and FIG. 16 are views for explaining the manufacturing process of the optical disk. 1 ... Inner circumference spacer, 3 ... 1st disk, 4 ... 2nd
Disc, 5 ... First disc substrate, 8 ... Second disc substrate, 11 ... First hub, 12 ... Second hub, 13 ...
... center hole, 14 ... cylindrical part, 15 ... inner collar part, 16 ... notch part, 17 ... gas venting groove, 20 ... through hole, 21 ... adhesive.

Claims (3)

[Claims] 1. A first disk support having an inner flange is fixed to the center of a first disk substrate with an adhesive, and a second disk support having an inner flange is bonded to the center of a second disk substrate. An optical disc in which a first disk substrate and a second disk substrate are arranged so that the inner flange portion of the first disk support and the inner flange portion of the second disk support face each other by fixing with an agent. An inner peripheral spacer is arranged on the outer periphery of the inner flange of the first and second disk supports, and an adhesive is used between the inner spacer and the disk substrate and between the inner spacer and the inner flange. Optical discs characterized by being connected together. 2. The disk support according to claim 1, wherein the disk support has a cylindrical portion having a center hole in a central portion thereof, and a vertical groove is provided on an outer peripheral surface of the cylindrical portion. An optical disc having a gas vent formed between a cylindrical portion and an inner peripheral surface of the disk substrate. 3. The optical disk according to claim 1, wherein an adhesive reservoir is formed on a surface of the disk support facing the other disk support.