JPH1166624A - Optical disk device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit evading influence on tilt accuracy of a disk substrate, to prevent corrosion of a reflection film, and to permit hardening processing for a short time by providing a metal reflection film on one pair of disk substrate having a recording film on one side plane respectively, and arranging a translucent resin spacer having the prescribed thickness and shape between one pair of disk substrate. SOLUTION: A recording film 107 is formed on a respective main plane of one pair of optical disk substrate 102, 102. A metal reflection film 109 is formed on a recording film of each disk substrate 102, ultraviolet curing adhesive 104 is applied almost circularly to a part in which the recording film 107 and the reflection film 109 of an outer peripheral end part and an inner peripheral end part of the disk substrate 102 are not formed. Successively, a translucent resin spacer 103 of a circular plate type is arranged so that the metal reflection film 109 of one side of disk substrate 102 is not covered by the adhesive 104. A pair of disk substrates 102 is closely contacted and the adhesive 104 is hardened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical disk for laser recording or reading and an optical disk device manufactured by the method, and mainly relates to an optical disk constituted by bonding a pair of disk substrates. The present invention relates to a structure of a device and a manufacturing method thereof.

[0002]

2. Description of the Related Art Generally, a disk substrate of an optical disk such as a video disk, a compact disk, and a disk memory is made by injection molding an acrylic resin or a polycarbonate among thermoplastic resins. The disk substrate thus manufactured is excellent as an optical disk substrate because it has excellent transferability of information patterns, transparency and heat resistance of the substrate, and low water absorption and birefringence. At present, optical disks represented by digital video disks (DVD) are write-only (DVD-RO).
M) and readable / writable (DVD-RAM), each having a structure in which two 0.6 mm thick substrates are bonded together. In a disc in which the recording surface is formed only on one side, the substrate on the opposite side is translucent, so that an ultraviolet ray is irradiated from the translucent substrate surface using an adhesive that is cured by ultraviolet light, A method of curing and bonding is used. However, discs with recording surfaces formed on both sides do not transmit ultraviolet light, so methods that do not use an ultraviolet curing method such as a double-sided adhesive tape, a two-component reactive adhesive, or a cationic epoxy adhesive are being studied. Have been.

The outline of each method will be described.
In the case of a double-sided adhesive tape: An adhesive layer is formed on a base film such as a PET (polyethylene terephthalate) film, and the adhesive layer is covered with a release paper to form a double-sided adhesive tape. Using such a double-sided adhesive tape, after peeling off the release paper, an adhesive layer is adhered to one substrate, and after peeling off the base film, the other substrate is opposed to and adhered. At this time, in order to remove bubbles trapped between the substrates, the temperature is raised to the temperature at which the adhesive layer flows, and pressure is applied to bond the bubbles while removing the bubbles, or to bond the two substrates in a vacuum. Thus, a method of preventing air bubbles from entering is adopted. In the case of a two-component reactive adhesive: a type of adhesive in which a curing reaction starts when two types of liquids are mixed or contacted. In the case of the mixing type, two liquids are mixed and supplied by a static nozzle or the like to the recording surface side of the disk substrate on which the recording surface of the pair of disk substrates is formed, and another substrate is bonded. Thereafter, leveling is performed by rotation, and a pair of disk substrates is bonded.
In the case of a cationic epoxy adhesive: An ultraviolet-curable protective coating agent is applied to the recording surface side of the disk substrate on which the recording surface is formed, and cured by ultraviolet light. A cationic epoxy adhesive is applied to the upper surface of the cured layer by printing, and a predetermined amount of ultraviolet rays is irradiated. After the same processing is performed on the other substrate, the surfaces of the pair of disk substrates to which the adhesive has been applied face each other and are pressed and cured.

[0004]

Problems to be solved by the above-described method include the following problems. The method of bonding is different between a case where the recording film is provided only on one surface of the pair of disk substrates and a case where the recording film is provided on both surfaces of the pair of disk substrates. Therefore, it is necessary to prepare a bonding device depending on the type of the disk. The tilt of the substrate after bonding is an important performance as a disk. However, when the adhesive is leveled by spinning, the tilting of the single disk substrate before bonding greatly depends on the tilt accuracy. That is, a disk substrate having a poor tilt accuracy cannot be used. Usually, an Al film is often used as the material of the reflection film, but some adhesives have a corrosive property and require a protective coating for anticorrosion. In the case of a reactive adhesive such as a two-component reactive type or an anaerobic reactive curing type other than the double-sided adhesive tape, it takes time to cure, so that it is not possible to proceed to the next step immediately after bonding. Therefore, an object of the present invention is to solve the above-described problems, and the bonding method does not differ depending on the type of the disk, and the tilt accuracy of the substrate after bonding is determined by the tilt accuracy of the disk substrate before bonding. Has no effect,
Further, an object of the present invention is to provide an optical disk device and a method for manufacturing the same, in which the reflective film is not corroded by the adhesive, and does not require a long time to cure unlike a reactive adhesive.

[0005]

The present invention has the following configuration to achieve the above object. According to the first aspect of the present invention, a metal reflective film provided on each of the recording films of a pair of disk substrates each having a recording film on one surface so as to remove an outer peripheral end and an inner peripheral end of the disk substrate; A translucent resin spacer arranged between a pair of disk substrates and having a predetermined thickness and a predetermined shape, and the disk substrate outer peripheral end and inner peripheral end where the metal reflection film is not formed. With the formed adhesive, in a state where the pair of metal reflective films of the pair of disk substrates are opposed to each other, the pair of disk substrates are mutually bonded with the adhesive via the spacer. An optical disk device characterized in that it is bonded and fixed.

According to a second aspect of the present invention, the adhesive is an ultraviolet-curable adhesive, and after the pair of disk substrates are bonded together, the adhesive is irradiated with ultraviolet light to remove the adhesive. The optical disk device according to the first aspect, wherein the pair of disk substrates is fixed by being cured. According to a third aspect of the present invention, there is provided the optical disc device according to the first or second aspect, wherein the spacer is a correction member for correcting a tilt of each of the pair of disk substrates.

According to a fourth aspect of the present invention, at least one of a pair of disk substrates in which a recording film is formed on each main surface and a metal reflection film is formed on each of the recording films, respectively. A step of applying an ultraviolet-curable adhesive to the outer peripheral end and the inner peripheral end and a portion other than on the metal reflection film, and the metal reflection film of at least one of the pair of disk substrates A step of disposing a translucent resin spacer thereon, and bonding the pair of disk substrates with the adhesive with the metal reflective films facing each other in a reduced-pressure atmosphere, and curing the adhesive with ultraviolet rays And a method of manufacturing an optical disk device.

According to a fifth aspect of the present invention, a step of forming a recording film on one main surface of each of a pair of disk substrates;
A step of forming a metal reflective film on the recording film in each of the disk substrates; and an outer peripheral portion and an inner peripheral end portion of at least one of the pair of disk substrates and a portion other than the metal reflective film. A step of applying an ultraviolet-curable adhesive to the portion, and on the metal reflective film of at least one disk substrate of the pair of disk substrates,
A step of disposing a translucent resin spacer, and a step of bonding the pair of disk substrates with the adhesive with the metal reflective films facing each other in a reduced-pressure atmosphere and curing the adhesive with ultraviolet rays. Are performed in order, and a method for manufacturing an optical disk device is provided.

According to a sixth aspect of the present invention, a step of forming a recording film on one main surface of each of a pair of disk substrates;
Forming a metal reflective film on the recording film in each of the disk substrates, and arranging a translucent resin spacer on the metal reflective film of at least one of the pair of disk substrates; Applying an ultraviolet-curable adhesive to the outer peripheral end and inner peripheral end of at least one of the pair of disk substrates, and to portions other than on the metal reflective film, Wherein the steps of: bonding the pair of disk substrates with the adhesive with the metal reflective films facing each other, and curing the adhesive with ultraviolet rays are sequentially performed. And a method for producing the same.

According to a seventh aspect of the present invention, when the spacer is disposed between the pair of disk substrates, the tilt of each of the pair of disk substrates is corrected by the spacer. The present invention provides a method for manufacturing an optical disk device according to any one of the above. According to an eighth aspect of the present invention, there is provided an optical disk device manufactured by the method for manufacturing an optical disk device according to any one of the fourth to seventh aspects.

[0011]

1A and 1B show a sectional structure of an optical disk device according to an embodiment of the present invention.
FIG. 2 shows a manufacturing process of the optical disk device. FIG.
2A, the optical disk device 101 has a structure in which a transparent annular plate-shaped resin spacer 103 is sandwiched between two circular disk substrates 102, and inner and outer peripheral ends are bonded with an adhesive 104. Has become. As shown in FIG. 1B in an enlarged manner, each disk substrate 102 is formed by laminating a dielectric film 106, a recording film 107, a dielectric film 108, and a reflective film 109 on a translucent resin substrate 105 in this order. It is configured. Here, as an example of the translucent resin spacer 103, a PET (polyethylene terephthalate) film,
Polycarbonate is an example of the translucent resin substrate 105, and ZnS- is an example of the dielectric films 106 and 108.
Sio ₂ , GeSbTe as an example of the recording film 107,
As an example of the reflection film 109, Al-2% Si can be used. As an example of the spacer 103, a spacer having a thickness of 50 μm ± 5 μm can be used. However, the thickness is not limited to this, but it is desirable that the variation in the thickness be within ± 10% of the thickness. The adhesive 104 is an ultraviolet-curable adhesive. The adhesive is applied at a portion where there is no recording film or metal reflection film, and is transparent to ultraviolet light. This enables curing in a short time.

A method of manufacturing the optical disk device will be described with reference to FIGS. As an example, each of the pair of disk substrates 102, 102 has a thickness of 0.6 mm, a diameter of about 120 mm, and a diameter of about 15 mm at the center.
It is assumed that the shape is a donut shape in which through-holes 102a, 102a are formed. First, in step S1 of FIG. 3, a recording film 107 is formed on one main surface of each of the pair of disk substrates 102, 102. Then, FIG.
In step S2, a metal reflection film 109 is formed on the recording film on each disk substrate 102. Then
In step S3 in FIG. 3, as shown in FIG. 2A, the outer peripheral edge and the inner peripheral edge of the disk substrate 101 are formed on the portions where the recording film 107 and the reflective film 109 are not formed.
An ultraviolet curable adhesive 104 is applied in a substantially annular shape.

Next, in step S4 of FIG. 3, as shown in FIG. 2B, a pair of disk substrates 102, 1
On the metal reflective film 109 of at least one of the disk substrates 102 of No. 02, a light-transmitting annular plate-shaped resin spacer 103 is arranged so as not to cover the adhesive 104. Next, in step S5 of FIG.
As shown in FIG. 3C, under a reduced pressure atmosphere, another disk substrate 102 faces each other, and a pair of disk substrates 102 and 102 are adhered to each other.
Ultraviolet rays are applied from above the one disk substrate 102 by 20 to cure the adhesive 104. The operation is performed under a reduced pressure atmosphere because if air containing moisture remains in the atmosphere where the disk is sealed, it causes corrosion. The adhesive 104 is applied to the disk substrate 102
Are arranged only on the inner peripheral end and the outer peripheral end of the disk substrate 102, even if the ultraviolet light is irradiated from above the disk substrate 102, the ultraviolet light is applied from the outside of the disk substrate 102 to the outer peripheral end of the disk substrate 102. At the inner peripheral end side, ultraviolet rays enter the inner peripheral side through the through-hole 102a of the disk substrate 102, and the adhesive 104 at the inner peripheral end
Irradiation can be reliably performed. Therefore, the adhesive 104 at both the inner peripheral end and the outer peripheral end of the disk substrate 102 can be reliably cured. Therefore, not only the pair of disk substrates 102, 102 having the recording films 107 on one side but also the pair of disk substrates 102, 102 having the recording films 107, 107 are bonded together via the spacer 103 and the adhesive 104 in the same manner. Pair of disk substrates 102, 10
By irradiating ultraviolet rays from above the adhesive 2, the adhesive 104 can be surely cured. Conventionally, when recording films 107, 107 are formed on both surfaces of a pair of disk substrates 102, 102, an adhesive is also formed on a portion of the spacer 103 between the inner peripheral end and the outer peripheral end. Therefore, it was not possible to irradiate the adhesive in this portion with ultraviolet rays. On the other hand, in the present embodiment, since there is no adhesive in this portion and the spacer 103 is disposed, there is no problem as in the related art. As an example, the reliability evaluation of the optical disk device manufactured by the optical disk device manufacturing method according to the present embodiment was performed under the condition of 80 ° C. and 85% × 96 hours (basic condition of the reliability evaluation of DVD). No problem occurred in both recording and reproduction characteristics.

According to the above-described embodiment, the optical disk device sandwiches the translucent resin spacer 103 between the two disk substrates 102, 102 to be bonded, and adheres only the inner peripheral end and the outer peripheral end. The structure is bonded by the agent 104. Therefore, since the tilt of the disk substrate itself is corrected by the translucent plate-shaped resin spacer 103, even a single disk substrate having a low tilt accuracy can be used, and an adhesive is applied on the reflective film. Therefore, corrosion of the reflective film 109 by the adhesive 104 is not a problem. Further, when an ultraviolet curable adhesive is used as the adhesive 104, a curing treatment can be performed in a short time. In addition, a pair of disk substrates 1 after bonding
Even when ultraviolet rays are irradiated on the disk substrates 02 and 102, the ultraviolet rays are irradiated from above or below the disk substrate 102, so that the adhesive 104 formed on the inner peripheral edge and the outer peripheral edge of the disk substrate 102 is irradiated with ultraviolet rays. Irradiation can be performed by the same method in both cases where the recording films 107 and 107 are formed on both of the pair of disk substrates 102 and 102 and when the recording films 107 are formed on only one of the disk substrates 102 and 102. To cure the adhesive. Therefore, in any case, since the optical disk device can be manufactured by the same bonding method, the same bonding machine may be used.

The present invention is not limited to the above embodiment, but can be implemented in various other modes. For example, as shown in FIG. 4, the order of the spacer disposing step and the adhesive applying step may be reversed. That is, step S
1, after forming the recording films 107, 107 and forming the metal reflection films 109, 109 in step S2, in step S13 of FIG.
A spacer 103 made of a light-transmitting resin is arranged on the metal reflection film 109 of at least one of the disk substrates 102 so as not to cover the adhesive 104. Next, in step S14 of FIG.
Recording film 107 and reflective film 1 at the outer and inner peripheral ends
09 is not formed and the spacer 10
The UV curable adhesive 1 is applied to the portion where no 3 is disposed.
04 is applied. Thereafter, a pair of disk substrates 102, 1
02 is bonded via the step 103 and the adhesive 104 so that the metal reflection films 109 and 109 face each other, and then the ultraviolet irradiation step of step S5 is performed in the same manner.

[0016]

According to the present invention, in an optical disk apparatus, a light-transmitting resin spacer is sandwiched between two disk substrates to be bonded, and only the inner peripheral end and the outer peripheral end are bonded with an adhesive. The structure has been. Therefore, since the tilt of the disk substrate itself is corrected by the translucent resin spacer plate, even a single disk substrate having a poor tilt accuracy can be used, and an adhesive can be applied on the reflective film. Therefore, corrosion of the reflective film by the adhesive does not pose a problem. Furthermore, when an ultraviolet-curable adhesive is used as the adhesive, the curing treatment can be performed in a short time.
Further, even when irradiating ultraviolet rays to the pair of disk substrates after bonding, by irradiating the ultraviolet rays from above or below the disk substrate, the ultraviolet light was formed on the inner peripheral edge and the outer peripheral edge of the disk substrate. Since the adhesive can be irradiated with ultraviolet rays, the ultraviolet rays can be irradiated by the same method both when the recording film is formed on both of the pair of disk substrates and when the recording film is formed only on one side. To cure the adhesive. Therefore, in any case, since the optical disk device can be manufactured by the same bonding method, the same bonding machine may be used.

[Brief description of the drawings]

FIGS. 1A and 1B are cross-sectional structural views of an optical disk device according to an embodiment of the present invention, and diagrams showing the other disk substrate, a spacer, and an adhesive in a dashed line. FIG. 1A is an enlarged cross-sectional view of the substrate in a circular region indicated by an arrow B in FIG.

FIGS. 2 (a), (b), and (c) are diagrams illustrating a manufacturing process of the optical disk device.

FIG. 3 is a flowchart showing a manufacturing process of the optical disc device according to the embodiment.

FIG. 4 is a flowchart showing a manufacturing process of an optical disc device according to another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 101 optical disk device 102 disk substrate 102 a through hole 103 translucent resin spacer 104 adhesive 105 translucent resin substrate 106 dielectric film 107 recording film 108 dielectric film 109 reflective film

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobutoshi Sozono 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] 1. A metal reflective film (109) provided on each of the recording films of a pair of disk substrates (102) each having a recording film (107) on one side thereof, except for the outer peripheral edge and the inner peripheral edge of the disk substrate. ), And a translucent resin spacer (10) disposed between the pair of disk substrates and having a predetermined thickness and a predetermined shape.
3) the adhesive (104) formed on the outer peripheral edge and the inner peripheral edge of the disk substrate on which the metal reflection film is not formed.
In a state where the pair of metal reflection films of the pair of disk substrates face each other, the pair of disk substrates are bonded to each other with the adhesive via the spacer and fixed. An optical disk device characterized in that: 2. The method according to claim 1, wherein the adhesive is an ultraviolet-curing adhesive, and after the pair of disk substrates are bonded to each other, the adhesive is irradiated with ultraviolet light to cure the adhesive, thereby forming the pair of disks. The optical disk device according to claim 1, wherein the disk substrate is fixed. 3. The optical disk device according to claim 1, wherein the spacer is a correction member that corrects a tilt of each of the pair of disk substrates. 4. An outer peripheral end of at least one of a pair of disk substrates having a recording film (107) formed on each main surface and a metal reflection film (109) formed on each of the recording films. (S3) applying an ultraviolet-curable adhesive (104) to the part and the inner peripheral end and to a part other than on the metal reflective film; and at least one of the pair of disk substrates A step (S4) of disposing a translucent resin spacer (103) on the metal reflection film; and bonding the pair of disk substrates with the adhesive with the metal reflection films facing each other in a reduced pressure atmosphere. At the same time, a step of curing the adhesive with ultraviolet rays (S5)
A method for manufacturing an optical disk device, comprising: 5. A step (S1) of forming a recording film (107) on one main surface of each of a pair of disk substrates (102).
Forming a metal reflective film (109) on the recording film in each of the disk substrates (S2); and forming an outer peripheral edge and an inner peripheral edge of at least one of the pair of disk substrates. And a step (S3) of applying an ultraviolet-curable adhesive (104) to portions other than on the metal reflection film, and on the metal reflection film of at least one of the pair of disk substrates. A step (S4) of disposing a translucent resin spacer (103); and bonding the pair of disk substrates with the adhesive with the metal reflection films facing each other in a reduced-pressure atmosphere, and bonding with the ultraviolet rays. Step of curing agent (S5)
And a method for manufacturing an optical disc device, wherein 6. A step (S1) of forming a recording film (107) on one main surface of each of a pair of disk substrates (102).
Forming a metal reflective film (109) on the recording film in each of the disk substrates (S2); and transmitting light on the metal reflective film of at least one of the pair of disk substrates. (S13) arranging the conductive resin spacer (103), and at the outer peripheral end and the inner peripheral end of at least one of the pair of disk substrates and at a portion other than on the metal reflective film. A step (S14) of applying an ultraviolet-curable adhesive (104), and bonding the pair of disk substrates with the adhesive with the metal reflective films facing each other in a reduced-pressure atmosphere, and bonding the substrates with ultraviolet rays. Step of curing agent (S5)
And a method for manufacturing an optical disc device, wherein 7. The optical disk device according to claim 4, wherein when the spacer is disposed between the pair of disk substrates, each tilt of the pair of disk substrates is corrected by the spacer. Manufacturing method. 8. An optical disk device manufactured by the method for manufacturing an optical disk device according to claim 4.