JP2001184740A - Disk bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a disk bonding method which can more effectively solve the problems of the insufficiency of adhesives near the central hole of a disk and the protruding of the adhesives by simple means. SOLUTION: This disk bonding method consists in bonding two disks Da and Db bored with the central hole H by allowing the UV curing resin adhesive L in an uncured state to stagnate between the two disks Da and Db and concentrically superposed the disks apart a prescribed spacing in parallel to each other in a vacuum chamber 10 in which the atmosphere state is maintained, then inserting an elastic holding member 3 into the central hole H in the state of reducing the pressure in the vacuum chamber 10, expanding the elastic holding member 3 in this state to oppress the central hole H of the two disks to hold the disks, then opening the vacuum chamber to the atmosphere to move the adhesive stagnating between the disks Da and Db toward the central hole H and regulating the adhesive L to a uniform thickness by rotating the disks Da and Db at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an optical disk, and more particularly to a method of bonding two disks to form a single disk.

[0002]

2. Description of the Related Art First, referring to the drawings, a description will be given of a conventional method of attaching disks. FIG. 5 is a process diagram for explaining a spin coating method which is one of the conventional disk bonding methods, and FIG. 5A shows a process in which an adhesive is applied to a bonding surface of one disk. FIG. B is a side view showing a step of applying an adhesive to the bonding surface of the other disk, and FIG. C is a step shown in FIGS. A and B. FIG. 7 is a side view showing a step of superposing and bonding two disks to which an adhesive has been applied.

Conventionally, generally for audio, video,
Other optical recording media for recording various types of information, such as optical discs that perform recording and / or reproduction by light irradiation,
Magneto-optical disks and the like are used, and fine irregularities such as phase pits and pre-grooves for information recording are formed on the information recording surface of these optical disks and the like. In response to a request for a large information recording capacity, the information
For example, a DV of a two-layer recording surface structure
An optical disk such as D is used.

[0004] Such an optical disk having a two-layer structure is generally integrally formed by joining two disks by bonding them together using an adhesive made of a liquid resin. As the adhesive, a liquid ultraviolet (UV) curable resin adhesive excellent in adhesiveness, ease of handling, stability against environmental changes, and the like is generally used.
Usually, as a method of bonding a disk using the UV-curable resin adhesive, a method generally called a spin coating method is used.

Next, a description will be given of a conventional disk bonding method of bonding two disks using this spin coating method. First, as shown in FIG. 5A, one disk Da is sucked on the turntable 100 using a vacuum chuck or the like.
While holding the turntable 100 together with the disk Da, the adhesive L is discharged from the nozzle 2 while rotating the disk Da, and the UV curable resin adhesive is dropped on an intermediate portion of the bonding surface of the disk Da, and the adhesive L is formed into an annular shape. Apply to.

Similarly, as shown in FIG. 5B, the other disk Db is sucked and held by a turntable 100 using a vacuum chuck or the like, and the turntable 100 is rotated by rotating the disk Db together with an adhesive from a nozzle 200. L is discharged, and the adhesive L is applied in a ring shape to an intermediate portion corresponding to the intermediate portion of the disk Da on the bonding surface of the disk Db.

Next, the discs Da and Db are superimposed on each other, and the adhesive L applied thereto is retained between the two discs, and is rotated at a high speed at a specific rotation speed. To adjust. That is, both disks Da, Db
Utilizing the centrifugal force to the outer periphery when the high-speed rotation is performed, the adhesive L between the two disks Da and Db is moved from the adhesive dropping position to the outer periphery of both disks Da and Db. Then, the adhesive L existing between the two disks Da and Db is stretched to a uniform thickness.
A disk having a layer recording surface structure can be obtained.

[0008]

However, in this spin coating method, since the two disks Da and Db are rotated at a high speed, the surplus adhesive is scattered outside the two disks near the outer peripheral portions of the two disks. The adhesive effect at the outer peripheral portions of both disks can be sufficiently ensured. On the other hand, when the amount of the adhesive dropped is small, the reflective films near the center holes of both disks Da and Db are not covered with the adhesive, so that the reflective films are oxidized. It becomes easier and adversely affects the disc life.

[0009] Further, since the thickness of the disk near the outer periphery and the inner periphery may vary, and the provisional UV curing near the center hole may be insufficient, both are hardened in the disk spin process before the UV curing treatment. Displacement between disks is also likely to occur.

If the amount of the adhesive dripped is excessively increased in order to prevent insufficient adhesion near the center of the disk, the adhesive protrudes from the center hole of the disk, the disk becomes dirty, the diameter of the center hole of the disk becomes irregular, and the disk transport section Problems such as soiling also occur.

Several inventions have been disclosed as methods for solving the problem of insufficient adhesion at the center of the disk. For example,
A method in which surplus adhesive is previously discharged to the end face of the center hole and the inner end face is smoothed over the entire circumference (Japanese Patent Laid-Open No. 59-1750)
46, JP-A-60-212840), a method in which a concave portion is formed on the inner peripheral end surface of the center hole of the disk and excess adhesive is accommodated in the concave portion (Japanese Patent Application Laid-Open No. 60-20332). A method of providing a slit on the circumference of the side of the center boss formed at the height of the bonding surface and absorbing the adhesive protruding from the inner peripheral end face of the center hole through a vacuum pump (Japanese Patent Laid-Open No. 62-12940). And so on.

The present invention is also intended to solve the above-mentioned problems. However, the problems of insufficient adhesive near the center hole of the disk and the protrusion of the adhesive are more effectively achieved by simpler means than the above-mentioned invention. Is to solve.

[0013]

Therefore, in the disk bonding method according to the first aspect of the present invention, in a negative pressure environment,
In parallel with each other with the uncured adhesive retained,
An elastic holding member is inserted between the two center holes of the two discs which are concentrically superimposed at predetermined intervals and have a center hole, and the elastic holding members in that state are expanded to expand the center holes of the two disks. To hold the discs, and then release the negative pressure environment to the atmosphere,
The adhesive remaining between the two disks is moved in the direction of the center hole of the two disks, and then the two disks are rotated at a high speed to adjust the adhesive to a uniform thickness, and the two disks are attached. The above problem is solved by adopting a matching method.

According to a second aspect of the present invention, in the disk bonding method according to the first aspect, the moving position of the adhesive moved in the direction of the center hole of the two disks is changed to the expanded elastic holding member. To form a gap between the peripheral surface of the elastic holding member and the inner peripheral end faces of the center holes of the two disks, and the atmospheric pressure generated in the gap and the atmospheric pressure of the outer peripheral portions of the two disks. The above-mentioned problem is solved by adopting a control method utilizing the balance of the above.

Furthermore, the invention according to claim 3 is characterized in that the adhesive according to claim 2 or 3 uses an ultraviolet curable resin adhesive.

Therefore, according to the disk bonding method of the first aspect, the adhesive can be spread with a uniform thickness up to the vicinity of the center holes of both disks, and the adhesive can protrude from the center holes. Can be prevented and both disks can be bonded together.

According to the disk bonding method of the present invention, the moving position of the adhesive in the vicinity of the center holes of both disks can be adjusted, and the adhesive can be spread more uniformly near the center holes. Both discs can be bonded together while effectively preventing the adhesive from protruding from the center hole.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A disk bonding method according to the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic diagram for explaining a first stage of the disk bonding method of the present invention, and FIG. 2 is a schematic diagram for explaining a second stage following the first stage shown in FIG. , FIG.
Is a schematic diagram for explaining a third stage following the second stage shown in FIG. 2, and FIG. 4 is a schematic diagram for explaining a fourth stage following the third stage shown in FIG. .

First, with reference to the drawings, members used in explaining each step of the disk bonding method of the present invention will be described. In the drawings, reference numeral 1 denotes a rotating support, and reference numeral 2 denotes a rotating support 1 thereof. The reference numeral 3 denotes an elastic holding member, the reference numeral 10 denotes a vacuum chamber, and the reference numerals Da and Db denote the pipes which are to be bonded to each other at the rotation center Co. Open the two discs,
Reference symbol L indicates an adhesive.

The rotating support 1 is a member that holds the disk by vacuum suction and rotates about a rotation center Co. The pipe 2 supplies air to expand the held elastic holding member 3. And a pipe connected to a supply / exhaust device (not shown) for exhausting gas in the expanding elastic holding member. The elastic holding member 3 is, for example, a balloon-shaped member formed of a silicon-based material, and has a cylindrical shape when inflated. Its outer diameter is smaller than the diameter of the center hole H of the disk to be bonded. For example, if the diameter of the center hole H of the disk is 15 mm, the outer diameter of the elastic holding member 3 is 15 mm.
The following is assumed.

Next, the first stage of the disk bonding method of the present invention will be described with reference to FIG. In the disk bonding step of the present invention, one of the disks Da to be bonded is sucked and held by the rotating support 1 with the bonding surface thereof facing upward in the vacuum chamber 10 which is open to the atmosphere. And rotate.
Next, for example, U
V-cured resin adhesive (hereinafter simply referred to as "adhesive")
For example, L is dropped in an annular shape, and the other disk Db to be bonded to the bonded surface is concentrically overlapped and integrated with the bonded surface facing the bonded surface. The elastic holding member 3 in a contracted state is inserted into the center holes H of the integrated disks Da and Db.

Next, the vacuum chamber 10 in which the discs Da and Db are placed is evacuated (negative pressure environment) in a state where the integrated elastic holding member 3 is inserted. As shown in FIG. 2, as shown in FIG. 2, air is supplied to the elastic holding member 3 through the pipe 2 to expand the cylindrical surface of the expanded elastic holding member 3 so that the cylindrical surface of the center hole H of both the disks Da and Db is formed. The discs Da and Db are held by pressing against the inner peripheral end face. This elastic holding member 3
Can be tightly held by the center holes H of the two disks Da and Db, and the two disks Da and Db can be held tight.
The displacement between b can be prevented.

The degree of vacuum in the vacuum chamber 10 is 133 to 1330
Pa (1 to 10 Torr) is appropriate. The material and the gas pressure required for the expansion of the elastic holding member 3 having the outer diameter are suitably 0.5 to 1.0 kg / m2. In addition, the thickness of the elastic holding member 3 is set to 1.0 to 1.5 mm so as to withstand this pressure.

Next, as shown in FIG. 3 as a third stage, while the elastic holding member 3 is in an expanded state,
The inside of the vacuum chamber 10 is opened to the atmosphere. In such a state, the adhesive L that is annularly retained between the disks Da and Db moves the space between its inner peripheral end and the center hole H of the disks Da and Db into the space between the disks Da and Db. Due to the atmospheric pressure of the outer peripheral portion of Db, it starts to move in the direction of the center hole H.

Then, as shown in FIG. 4, when the adhesive L almost reaches the center hole H of both disks Da and Db,
The expanding elastic holding member 3 is decompressed and reduced through the pipe 2, and a gap G is formed between the cylindrical surface of the elastic holding member 3 in this state and the center holes H of both disks Da and Db. By setting the side adhesive and the outer peripheral adhesive to the same atmospheric pressure, the movement of the adhesive L moved to the center holes H of the discs Da and Db is stopped.

Next, both disks Da and Db on which the adhesive L in such a state is present are rotated at a high speed by the rotary support 1 to adjust the thickness of the adhesive L uniformly.
The adhesive is irradiated with ultraviolet rays to be cured.

By employing the disk bonding method of the present invention as described above, a bonded disk having a uniform thickness from the outer peripheral portion to the center hole can be obtained.

[0029]

As described above, according to the present invention, there are provided: 1. Adhesion failure at the inner periphery of the two discs bonded together is reduced. 2. The protrusion of the adhesive from the center holes of both disks after bonding is reduced. 3. The displacement between the bonded upper disk and lower disk is reduced. 4. Since the adhesive can surely protect the reflective film as a protective film, the disk life can be extended. 5. Since the protrusion of the adhesive is reduced, the center hole defect of the disk after UV curing is reduced. 6. Since the protrusion of the adhesive is reduced, the contamination of the disk transport member and the like before UV curing is reduced. Numerous excellent effects can be obtained, such as a simple and inexpensive device.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a first stage of a disk bonding method according to the present invention.

FIG. 2 is a schematic diagram for explaining a second stage following the first stage shown in FIG. 1;

FIG. 3 is a schematic diagram for explaining a third step following the second step shown in FIG. 2;

FIG. 4 is a schematic diagram for explaining a fourth step following the third step shown in FIG. 3;

FIG. 5 is a process diagram for explaining a spin coating method which is one of the conventional disk bonding methods, and FIG. 5A shows an adhesive applied to a bonding surface of one disk. A side view showing a process, FIG. B is a side view showing a process of applying an adhesive to the bonding surface of the other disk, and FIG. C is shown in FIGS. A and B. It is a side view which shows the process of laminating | stacking and sticking two disks which apply | coated the adhesive agent in the process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotary support, 2 ... Pipe, 3 ... Elastic holding member, 10
... vacuum chamber, Da, Db ... disk, H ... disk Da,
Db center hole, L: adhesive

Claims (3)

[Claims] In a negative pressure environment, two discs having an uncured adhesive retained in parallel and concentrically overlapped at predetermined intervals and having a center hole are kept parallel to each other. Insert the elastic holding member over both center holes, expand the elastic holding member in that state and press the center holes of both disks to hold the two disks,
The negative pressure environment is released to the atmosphere, the adhesive remaining between the two disks is moved in the direction of the center hole of the two disks, and then the both disks are rotated at a high speed so that the adhesive has a uniform thickness. And bonding the two disks together. 2. The moving position of the adhesive, which has moved in the direction of the center holes of the two disks, is caused by contracting the expanded elastic holding member so that the peripheral surface of the elastic holding member and the center holes of the two disks are moved. 2. The disc sticking according to claim 1, wherein a gap is formed between the disc and the peripheral end face, and control is performed using a balance between the atmospheric pressure generated in the gap and the atmospheric pressure at the outer peripheral portions of the two discs. Matching method. 3. The method according to claim 1, wherein the adhesive is an ultraviolet curable resin adhesive.