JP2512710B2 - Optical disc and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical disc and a method for manufacturing the same.

[Conventional technology]

FIG. 9 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. The disk 53 is composed of a transparent disk substrate 54 and a recording film 55 provided on one surface thereof, and the recording film 55 has concentric pregroups.
56 is formed, and the two disks 53 are arranged so that the recording films 55 face each other. The recording film 55
Is composed of a thin transparent resin film and a reflective film formed thereon.

On the other hand, the hub 51 is made of a material having abrasion 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 hall 57 is provided for performing. Reference numeral 58 in the figure denotes an air gear formed between the two optical disks 53.

10 to 12 are explanatory views showing the manufacturing process of this optical disk, and the conventional manufacturing method will be described based on these drawings.

First, as shown in FIG. 10, the pre-groove 56 is formed on the surface.
On the stamper 60 having a large number of concentric circular grooves 59 corresponding to the above, the uncured UV curable resin 61 having fluidity is dropped. 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 its central portion 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 is pushed and expanded in the outer peripheral direction without containing bubbles between the both, and the grooves 59 are also filled with the ultraviolet curable resin 61.

Then, as shown by the arrow in FIG. 11, the disk substrate 54
Ultraviolet rays 62 are irradiated from above to cure the ultraviolet curable resin 61. Next, when the disk substrate 54 is peeled off from the stamper 60, the cured resin film is also separated from the stamper 60 together with the disk substrate 54, thereby forming the recording film 55 in which the pregroup 56 is formed. In this way, the replica process is completed.

Next, the center position of the disk substrate 54 is optically determined by using the pre-group 56, and the hub 51 and the outer peripheral spacer 52 are adhered and combined based on the optical position to manufacture an optical disk as shown in FIG. To do.

[Problems to be solved by the invention]

However, since the conventional optical disk hub 51 is manufactured by cutting from a metal material, it has a lot of man-hours for manufacturing and causes a high cost.

Further, since the hub 51 is relatively thick as shown in FIGS. 9 and 12, it is heavy. Therefore, when the rotation of the disk is stopped, a large inertial force acts on the hub 51, so if the adhesive force between the hub 51 and the disk substrate 54 is weak, there is a concern that the adhesive parts of the two will be broken and separated. is there.

In addition, the conventional manufacturing method has drawbacks such as difficulty in centering when combining the hub 51 and the disk substrate 54, a problem in reliability, and poor productivity.

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 abrasion resistance because the optical disc is repeatedly attached to and detached from the device.
Generally, metal is used. In this way, the thermal expansion coefficient of the disk substrate 54 made of synthetic resin or glass and the metal hub 51 are significantly different on the order of 10 times.
In order to prevent the disk substrate 54 from being deformed due to the thermal expansion of 51, a slight clearance is provided at the joint between the disk substrate 54 and the hub 51. This clearance is also necessary to facilitate the joining of 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 with the center misalignment generated
When the hub 51 and the hub 51 are adhered to each other, and the information is written or read by mounting the hub 51 on the recording / reproducing apparatus, the optical disk is positioned in the apparatus by the hub 51 being fitted to the spindle as described above. Therefore, the pre-groove 56 on the recording film 55 rotates in an eccentric state with respect to the center of rotation of the optical disk, and accurate tracking cannot be performed, which causes a problem in reliability. In particular, recently, the pitch of the pre-grooves 56 has become extremely small, about 1.6 μm, along with the high density recording, so that the influence of the track deviation as described above directly appears on the characteristics.

In order to prevent such a situation from occurring, when the disk substrate 54 and the hub 51 are bonded together, the positional relationship between the two is performed one by one while observing them with a microscope, which results in extremely high productivity. It had drawbacks such as badness.

In addition, when the hub 51 and the disk substrate 54 are bonded with an adhesive, the hub 51 and the disk substrate 54 may be misaligned.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks of the prior art, and to provide an optical disk having good productivity and high reliability, and a manufacturing method thereof.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention provides a disk-shaped support such as a cap having a cylindrical portion and a collar portion, and a center hole provided at the top of the cylindrical portion, and a through hole in the central portion. And a disk formed with a disk, the cylindrical portion of the disk support is inserted into the through hole of the disk, and the flange of the disk support and the disk are integrally connected by an adhesive. To do.

In order to achieve the above-mentioned object, the present invention further provides a disk support such as a cap-shaped hub which is provided at the center of the disk substrate, and a recording film is provided on the disk substrate with reference to the center of the disk support. It is characterized by that.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a double-sided recording type optical disc according to the first embodiment, and FIGS. 2 to 5 are views for explaining a manufacturing process of the optical disc.

In the case of this optical disk, as shown in FIG. 1, the hub 1,
Two disks 4 are fixed so as to face each other via an inner peripheral spacer 2 and an outer peripheral spacer 3. The disk 4 is composed of a transparent disk substrate 5 and a recording film 6 provided on one surface thereof, and a concentric or spiral pre-groove 7 is formed on the recording film 6 to form two disks. The recording films 4 are arranged so that the recording films 6 face each other.

The hub 1 has a cap shape, a center hole 8 with high processing accuracy is formed at a position corresponding to the top of the hub 1, and a flange 9 is provided on the outer peripheral portion. The inner diameter of the inner peripheral spacer 2 is designed to be slightly larger than the outer diameter of the cylindrical portion 10 of the hub 1.

The hub 1 is made of a wear-resistant material such as stainless steel or ceramics. The inner and outer spacers 2 and 3 are made of metal such as stainless steel or synthetic resin such as polycarbonate resin or epoxy resin. On the other hand, the disk substrate 5
Is made of a synthetic resin such as a polycarbonate resin or an epoxy resin or a transparent material such as glass.

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

First, as shown in FIG. 2, a center hole 8 is provided in the center of the hub 1 with high processing accuracy, while the recording film 6
A through hole 11 is provided in the central portion of the disk substrate 5 on which the holes are not formed. Then, an adhesive (not shown) is applied to the lower surface of the flange portion 9 and the outer peripheral surface of the cylindrical portion 10 of the hub 1, and the cylindrical portion 10 is inserted into the through hole 11 of the disk substrate 5 to form the hub 1 and the disk substrate. 5 and 1 are bonded together.

Next, as shown in FIG. 3, the hub-equipped disk substrate 5 is pressed onto the stamper 12, and a concentric or spiral groove 13 corresponding to the pre-groove 7 is formed on the upper surface of the stamper 12. A positioning pin 14 is provided at the center of the groove 13, and a predetermined amount of uncured ultraviolet curable resin 15 having fluidity is dropped on the stamper 12.

As shown in the figure, the disk substrate 5 is lowered onto the stamper 12 in a state where the disk substrate 5 is slightly curved so that the central portion of the disk substrate 5 faces downward, and the positioning pin is placed in the center hole 8 of the hub 1.
Insert 14. As a result, the position of the disk substrate 5 on the stamper 12 is correctly determined. When the disk substrate 5 is pressed against the stamper 12 side in this state, the ultraviolet curable resin 15 is spread between the both in the outer peripheral direction without containing bubbles, and the uncured resin 15 is also filled in the grooves 13. .

Thereafter, as shown in FIG. 4, while the disk substrate 5 is completely pressed against the stamper 12, ultraviolet rays 16 are evenly irradiated from above to cure the ultraviolet curable resin 15. Next, when the disk substrate 5 is peeled off from the stamper 12, the cured resin film is also separated from the stamper 12 together with the disk substrate 5, whereby the recording film 6 having the pre-groove 7 is formed.

In this way, two discs 4 for which the replica process has been completed are prepared, one disc 4 is placed on the base 17 as shown in FIG. 5, and a positioning pin provided on the upper surface of the base 17 By inserting the center hole 8 of the hub 1 into the disk 18, the disk 4 is positioned on the base 17. Then, the inner peripheral spacer 2 and the outer peripheral spacer 3 having an upper surface and a lower surface coated with an adhesive (not shown) are placed at predetermined positions on the disk 4, and the other disk 4 is adhered to the upper surface thereof with the adhesive 19
(See FIG. 1), and the center hole 8 of the hub 1 in the disk 4 is inserted into the positioning pin.

As a result, the lower disk 4 and the upper disk 4 are superposed at the correct position, and the two disks 4, the inner peripheral spacer 2 and the outer peripheral spacer 3 are integrally bonded, and the optical disk as shown in FIG. Is obtained.

The inner peripheral spacer 2 is adhered to the upper and lower hubs 1 on the inner side thereof, and although not shown, the inner peripheral spacer 2 is joined to the upper and lower discs 4 as well as the inner peripheral spacer 2 and the upper and lower hubs. The adhesive layers that are respectively interposed on the joint surfaces with 1 are continuous with each other.

FIG. 6 is a diagram showing a second embodiment of the present invention. The difference between this embodiment and the first embodiment is that when the lower disk 4 and the upper disk 4 are combined, no adhesive is used. This is the point where spot welding 20 was performed.

FIG. 7 is a view showing a third embodiment of the present invention. This embodiment shows a single-sided recording type optical disk. Therefore, one disk 4 is used, and a protective plate 21 having the same diameter as the disk 4 is attached so as to face it.

As the protective plate 21, for example, a metal such as stainless steel,
A synthetic resin such as polycarbonate or ceramics is used.

FIG. 8 is a diagram showing a fourth embodiment of the present invention, which is different from the third embodiment in that the cylindrical portion 22 is integrally provided on the inner periphery of the protective plate 21 and the inner spacer 2 is omitted. Is.

In the case of these third and fourth embodiments, the hub 1
Is higher than that used in the first and second embodiments, and when the protective plate 21 is combined with the disk 4, the top of the hub 1 serves as an insertion guide for the protective plate 21. Be useful.

FIG. 13 is a diagram for explaining the fifth embodiment of the present invention. In the case of this embodiment, the flange portion 9 provided on the outer peripheral portion of the hub 1 is arranged so as to abut on the outer surface of the disk substrate 5, and the space between the disk substrate 5 and the flange portion 9 and between the hub 1 and the disk substrate 9 is set. The substrate 5 and the through hole 11 are adhered by an adhesive. Further, as shown in the figure, the central portions of the cap-shaped hub 1 are opposed to each other and integrally bonded by an adhesive 19.

In this embodiment, unlike the case of the first embodiment,
The inner peripheral spacer 2 is not used.

Further, unlike the above embodiment, it is possible to provide a through hole in the central portion of the disk substrate and integrally provide a disk support inside the through hole by a molding method.

[Advantages of the Invention] The present invention has the above-mentioned configuration, and since the thin-walled cap-shaped disk support can be continuously and easily formed by press working, molding, or the like, the productivity is good. is there.

Further, since this disk support is lighter than the conventional one, the inertial force during rotation is small, and therefore the adhesion between the disk support and the disk substrate can be maintained for a long time.

Furthermore, it is not necessary to center the disk substrate and the disk support, and the center of the disk support and the center of the pre-group are always aligned, eliminating the harmful effects of center misalignment and manufacturing a highly reliable optical disk. You can

Furthermore, since it is not necessary to perform the work of centering the disk substrate and the disk support while looking at the microscope, the productivity can be greatly improved and the production cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical disk according to a first embodiment of the present invention, FIGS. 2, 3, 4, and 5 are views for explaining a manufacturing process of the optical disk, and FIG. Figure, Figure 7, Figure 8
FIG. 13 is a sectional view of an optical disk according to another embodiment of the present invention, FIG. 9 is a sectional view of a conventional optical disk, FIG. 10, FIG.
11 and 12 are views for explaining the manufacturing process of the optical disk. 1 ... Hub, 4 ... Disk, 5 ... Disk substrate, 6
…… Recording film, 7 …… Pregroove, 8 …… Center hole, 9 …… Brim part, 10 …… Cylinder part, 11 …… Perforated hole, 12 ……
Stamper, 13 ... Groove.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G11B 23/00 601 G11B 23/00 601L 601X

Claims (7)

(57) [Claims] 1. A cap-shaped disk support having a cylindrical portion and a brim portion, a center hole being provided at the top of the cylindrical portion, and a disk having a through hole formed in the central portion thereof. An optical disk, wherein the cylindrical portion of the disk support is inserted into the through hole, and the flange of the disk support and the disk are integrally connected by an adhesive. 2. A method of manufacturing an optical disk, wherein a cap-shaped disk support is provided in the center of the disk substrate, and a recording film is provided on the disk substrate with reference to the center of the disk support. 3. In claim (2),
Positioning of the disk substrate with respect to the stamper by providing an engaging portion on the disk support and an engaging portion on the duplication stamper and engaging the engaging portion of the disk support with the engaging portion of the stamper. A method for manufacturing an optical disk, which comprises: 4. In the scope of claim (2),
A method of manufacturing an optical disk, characterized in that a through hole is provided in a central portion of the disk substrate, and a disk support is integrally provided inside the through hole by a molding method. 5. In the claim (2),
A through hole is provided in the center of the disk substrate, and the cylindrical portion of the cap-shaped disk support is inserted inside the through hole, and the flange of the disk support is opposite to the surface of the disk substrate on which the recording film is formed. After the recording films are provided on the two disk substrates respectively, the disk substrates are arranged so that the recording films face each other, and the facing surfaces of the disk supports are integrally bonded. A method for manufacturing an optical disk, which is characterized by: 6. In the claim (5),
A method for manufacturing an optical disk, characterized in that a ring-shaped inner peripheral spacer is fitted to a central portion of the disk support, which projects from the disk substrate. 7. In the claim (6),
An optical disk characterized in that the joint surface between the inner peripheral spacer and the disk substrate and the joint surface between the inner peripheral spacer and the disk support are adhered by an adhesive layer, and the adhesive layer is continuous. Manufacturing method.