JPH05198007A - Optical information recording medium and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an optical information recording medium having a high yield of non-defective products and a close-bonded structure excellent in environmental resistance. [Structure] A silicon-based resin that cures two optical recording single plates 5a and 5b having a thin film 3 involved in recording and reproducing information on a pre-format pattern forming surface of a replica substrate 1 at a temperature of 80 ° C. or less. Stick 11 together. The silicon-based resin is applied to the optical recording single plate by a method other than the roll coating method, for example, a spin coating method. A protective film for protecting the thin film 3 is unnecessary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium having a contact bonding structure in which two optical recording single plates are concentrically bonded via an adhesive layer.

[0002]

2. Description of the Related Art Conventionally, as a bonding structure of a double-sided recording type optical information recording medium, there is known a so-called contact bonding structure in which a replica substrate of two optical recording single plates and recording surfaces are bonded together via an adhesive layer. Has been.

FIG. 7 is a cross-sectional view showing an example of a conventionally known optical information recording medium of this type, in which the preformat pattern forming surface 2 of the replica substrate 1 includes at least a recording film or a reflecting film. Two optical recording veneers 5 each carrying one or a plurality of layers of thin film 3 (the case of a single layer is shown in the figure), and this thin film 3 is covered with a protective film 4.
The thin film 3 and the protective film 4 are affixed to the insides a and 5b, and the protective film 4 and the replica substrate 1 are bonded to each other with an adhesive layer 6 interposed therebetween.

As the adhesive constituting the adhesive layer, a hot-melt adhesive can be used because it can be applied using a roll coater and can be solidified in a relatively short time, and is excellent in mass productivity. Has been prized.

[0005]

However, since the adhesive force of the hot melt adhesive is remarkably reduced at high temperature, the reliability is poor at high temperature, and the adhered double-sided recording type optical information recording medium is peeled off. Is likely to cause inconvenience. Also, since the hot-melt adhesive has a high water absorption rate, the thin film necessary for recording and reproducing information is easily corroded,
It is difficult to produce an optical information recording medium having a close-bonding structure that is excellent in long-term storage stability. Furthermore, when the hot melt adhesive is applied using a roll coater, it is an essential condition to provide the protective film 4 on the thin film 3 as described above in order to prevent the thin film 3 from being damaged by the roller.
There is an inconvenience that the manufacturing process becomes complicated and the cost of the optical information recording medium becomes high. In addition, according to the roll coater, the thickness of the adhesive layer 6 becomes uneven due to nonuniform roller spacing, flexure of the replica substrate 1, etc., and in the worst case, a portion where the adhesive is not applied is likely to occur. Another problem is that it is difficult to increase the yield of non-defective products. In order to solve such a problem, it is necessary to select an adhesive which has a strong adhesiveness regardless of temperature and which can be uniformly applied without using a roll coater.

The present invention has been made to solve the above problems, and an object thereof is to provide an optical information recording medium excellent in reliability and durability, and such an optical information recording medium. The object is to provide a method for producing a good yield.

[0007]

According to the present invention, in order to solve the above-mentioned problems, one or a plurality of thin films required for recording and reproducing information are carried on a preformat pattern forming surface of a replica substrate. In an optical information recording medium in which the thin film is placed inside, and the thin film and the replica substrate are bonded together via an adhesive layer, an optical recording single plate of 80 ° C. or less is used as an adhesive forming the adhesive layer. A silicon-based resin that cures at the above temperature was used.

As the above-mentioned silicone resin, in order to prevent the corrosion of the above-mentioned thin film, dealcohol type, dealt oxime type and deacetic acid type silicone resins are preferable, and a mixture of two or more kinds of these silicone resins is preferable. It can also be used.

Regarding the method of manufacturing the optical information recording medium, two optical recording single plates each having one or a plurality of thin films necessary for recording and reproducing information on the preformat pattern forming surface of the replica substrate are carried out. Of the optical recording single plate and a pre-format pattern forming surface of the replica substrate are spin-coated with a silicon-based resin that cures at a temperature of 80 ° C. or lower, and then the thin film is formed. A method in which the two optical recording veneers are closely contacted with each other inside and the two optical recording veneers are concentrically attached to each other;
And an adhesive is applied in a ring shape on the thin film of one of the optical recording single plates, and then the two optical recording single plates are adhered to each other with the thin film inside, and the adhesive is applied to the thin film and the thin film. It is possible to use any of the methods in which the pre-format pattern forming surface of the replica substrate is uniformly spread and the two optical recording single plates are concentrically attached.
Which method is adopted depends on the viscosity of the adhesive. The above method is suitable when an adhesive having a viscosity of about several centipoise to 1000 centipoise is used, and when an adhesive having a viscosity higher than that is used. Is preferably the above method. In the case of adopting the above method, it is possible to apply the adhesive in a ring shape on the circumferential region that bisects the area of the replica substrate into the inner peripheral portion and the outer peripheral portion. It is preferable to do so. Also in the case of adopting the above method, the above-mentioned silicone resin can be used as the adhesive.

[0010]

[Function] Since the silicone resin has a remarkably smaller water absorption rate than the hot-melt adhesive, it has a high effect of preventing the corrosion of the recording film or the reflective film, and produces an optical information recording medium excellent in long-term storage stability. can do. In addition, since the silicone-based resin has higher adhesiveness to the metal film and higher adhesive strength at high temperature than the hot-melt adhesive, the optical information recording medium is less likely to cause peeling and has excellent reliability and durability. Can be produced. Furthermore, as a silicone resin, 80
If a material that cures at a temperature of ℃ or less is used, the optical recording veneer can be bonded without adversely affecting the replica substrate and the thin film. Further, when the adhesive is applied to the optical recording single plate by the above-mentioned method, the recording film, the reflection film, or the like is not destroyed when the adhesive is applied. Therefore, it is not necessary to cover a thin film such as the recording film or the reflective film with the protective film, and the manufacture of the optical information recording medium is facilitated. further,
Since the adhesive can be applied uniformly regardless of the deflection of the replica substrate, the yield of non-defective products can be increased.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the optical information recording medium according to the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of an optical information recording medium according to this example, FIG. 2 is a plan view thereof, and FIG. 3 is a plan view showing a method of applying an adhesive.

As shown in FIG. 1, an optical information recording medium of this example has a preformat pattern forming surface 2 of a replica substrate 1 on which one or a plurality of thin films 3 including at least a recording layer or a reflective layer are deposited. Two optical recording single plates 5a and 5b
However, the thin film 3 is placed inside, and the thin film 3 and the replica substrate 1 are bonded to each other with the adhesive layer 11 interposed therebetween, so that a so-called contact bonding structure is assembled.

As shown in FIG. 2, the replica substrate 1 is made of a transparent ceramic material such as glass or a transparent resin material such as polycarbonate, polymethylmethacrylate, polymethylpentene, or epoxy, and has a center hole 1a at its center. It is formed in a disk shape having a desired diameter.
The pre-format pattern 2 includes a guide groove for guiding the recording / reproducing light beam spot, a pre-pit for displaying the address of each track or sector, and a spiral or concentric shape concentric with the center hole 1a. Arranged in. In addition, pre-format pattern 2
The method of forming the above is a matter that is publicly known and has no direct relation to the gist of the present invention, and thus the description thereof will be omitted. Although not shown in FIGS. 1 and 2, a center hub for inserting a spindle provided in the drive device can be attached to the opening position of the center hole 1a of the replica substrate 1.

The thin film 3 necessary for recording and reproducing information is formed as a single layer or a laminated body of a plurality of thin films, as required. For example, in a magneto-optical recording medium, a first enhance film made of an inorganic dielectric material having a refractive index higher than that of the replica substrate 1 from the replica substrate 1 side, a magnetic film as an information recording medium, and a first enhance film. Second made of the same kind of inorganic dielectric as
The thin film 3 can have a four-layer structure including an enhancement film and a reflective film made of metal such as aluminum.

As the adhesive constituting the adhesive layer 11, 8
A silicon-based resin that cures at a temperature of 0 ° C. or lower is used. Examples of this type of adhesive include a dealcohol-free type, a deoxidizing type, and a non-alcoholic type in order to prevent corrosion of the thin film 3.
And deacetic acid type silicone resins are preferable, and a mixture of two or more kinds of these silicone resins can also be used. As a method of applying the silicon-based resin to the optical recording single plates 5a and 5b, a spin coating method can be adopted, or the thin film 3 of either one of the optical recording single plates 5a and 5b can be used.
It is also possible to adopt a method in which a silicon-based resin is applied in a ring shape on the top. In the latter case, one optical recording veneer coated with a silicon-based resin and the other optical recording veneer not coated with a silicon-based resin are adhered to each other with the thin film 3 inside, and the silicon-based resin is applied to both sides. Optical recording medium 5a, 5b
The two optical recording media 5a and 5b can be adhered to each other by a method such that they are spread uniformly over the entire surface of the optical recording media. In this case, as shown in FIG. 3, the silicon-based resin B is formed into a ring shape on the circumferential area A that divides the area of the replica substrate 1 into two parts, the inner peripheral part 1 ₁ and the outer peripheral part 1 _2. The application is preferable in order to spread the silicon-based resin uniformly. The method shown in FIG. 3 can also be applied to the case where an adhesive other than silicone resin is used.

The optical information recording medium of the above-mentioned embodiment is used as an adhesive for adhering the optical recording veneers 5a and 5b to each other, having a water absorption rate significantly smaller than that of the hot-melt adhesive and having good adhesion to the metal film. Since it uses a silicon-based resin that has high adhesiveness at high temperature, long-term storage stability, reliability,
An optical information recording medium having excellent durability can be manufactured. In addition, since the silicone resin that cures at a temperature of 80 ° C. or less is used, the replica substrate 1 and the thin film 3 are not thermally adversely affected. Furthermore, since the adhesive can be applied without using a roll coater, the thin film 3 such as the recording film or the reflective film is not destroyed during the adhesive application. Therefore, it is not necessary to cover the thin film 3 with the protective film, and the manufacture of the optical information recording medium can be facilitated. In addition, since the adhesive can be uniformly applied regardless of the deflection of the replica substrate, the yield of non-defective products can be increased.

The effects of the present invention will be clarified below with reference to experimental examples of the present invention. <Experimental Example 1> A first enhance film, a magnetic film, a second enhance film and a reflective film are formed on a preformat pattern forming surface of a polycarbonate replica substrate having an inner diameter of 15 mm, an outer diameter of 130 mm and a thickness of 1.2 mm. A plurality of magneto-optical recording veneers were produced by sequentially performing sputter film formation. After that, two magneto-optical recording single plates were taken out of these, and bonded with a dealcohol type silicon resin (37X-033 manufactured by ThreeBond Co., Ltd.) to obtain a close-bonding type light according to the present invention. A magnetic recording medium was produced.
However, the thickness of the adhesive layer was about 30 μm. Further, the other two are taken out from the plurality of magneto-optical recording single plates, and the first enhancing film, the magnetic film, the second enhancing film, and the reflecting film are combined with an ultraviolet curable resin (manufactured by Dainippon Ink and Chemicals, Inc.). SD-17) protective film, and then these two magneto-optical recording veneers are bonded with a hot melt adhesive to form a close-bonded magneto-optical recording medium according to a comparative example (conventional example). Was produced.

These magneto-optical recording media are used at temperatures of 80 ° C.
When the number of defects generated in the magnetic layer was measured at regular time intervals after being left in an environment where the relative humidity was 90%, the magneto-optical recording medium according to the comparative example was measured immediately after the start of the test as shown in FIG. While the number of defects gradually increased and the number of defects rapidly increased after 2000 hours, in the magneto-optical recording medium according to the present invention, the number of defects gradually increased immediately after the start of the test. Is slower than the comparative example, and is 3000
The number of defects did not increase until time passed. From this, the magneto-optical recording medium according to the present invention, as compared with the magneto-optical recording medium according to the comparative example, cracks and peeling in the thin film under high temperature and high humidity environment, less likely to cause corrosion, etc., excellent in environmental resistance I understand that.

Experimental Example 2 As shown in FIG. 5, the width W is 2
A plurality of polycarbonate plates having a length of 0 mm, a length L of 60 mm and a thickness t of 1.2 mm were prepared. Then, two polycarbonate plates were taken out from these, and 0.5 g of a dealcohol-type silicone resin B was used for the tips (regions with a width W of 20 mm and a length l of 20 mm).
(37X-033 manufactured by ThreeBond Co., Ltd.) was used for adhesion. Then, the bonded body was baked at 80 ° C. for 1 hour to prepare a test piece shown in FIG. Further, the other two pieces were taken out of the plurality of polycarbonate plates, and these were adhered with a hot melt adhesive to prepare a test piece shown in FIG.

FIG. 6 shows each of these test pieces at 20 ° C. and 60 ° C.
Maximum stress value (unit: Kg / cm) when stretched in the longitudinal direction (direction of arrows C and D) under each temperature condition of ℃ and 80 ℃
² ) is shown. As is clear from the data in FIG. 6, the test piece bonded with the silicone resin has a bonding strength at 20 ° C. about three times higher than that of the test piece bonded with the hot melt adhesive, and The strength does not decrease at all up to 80 ° C, whereas the test piece bonded with the hot melt adhesive has the bonding strength at 60 ° C decreased to about 8% of the bonding strength at 20 ° C. From this, it can be seen that the use of the silicon-based resin makes it possible to manufacture a contact-bonding type optical information recording medium having higher reliability than the case of using the hot-melt adhesive.

In the above embodiments, a disk-shaped optical information recording medium has been described as an example, but the present invention can be applied to optical information recording media of other shapes such as an optical card.

[0022]

As described above, according to the present invention,
As an adhesive for bonding optical recording veneers, a silicone-based resin that has significantly lower water absorption than hot-melt adhesives, high adhesiveness with metal films, and high adhesive strength at high temperatures. Since it is used, an optical information recording medium excellent in long-term storage stability, reliability, and durability can be manufactured.
Further, since the silicone resin that is hardened at a temperature of 80 ° C. or less is used, the replica substrate and the thin film are not thermally adversely affected. Furthermore, since the adhesive can be applied without using a roll coater, the thin films such as the recording film and the reflective film are not destroyed when the adhesive is applied.
Therefore, it is not necessary to cover the thin film with the protective film, and the manufacture of the optical information recording medium can be facilitated. In addition, since the adhesive can be uniformly applied regardless of the deflection of the replica substrate, the yield of non-defective products can be increased.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical information recording medium in an example.

FIG. 2 is a plan view of an optical information recording medium according to an example.

FIG. 3 is a plan view showing an example of a method of applying an adhesive.

FIG. 4 is a graph showing the results of environment resistance test.

FIG. 5 is a perspective view of a tensile test piece.

FIG. 6 is a table showing the tensile test results.

FIG. 7 is a cross-sectional view of an optical information recording medium according to a conventional example.

[Explanation of symbols]

 1 Replica Substrate 2 Preformat Pattern 3 Thin Film 5a Optical Recording Single Plate 5b Optical Recording Single Plate 11 Adhesive Layer Made of Silicon Resin

Claims (9)

[Claims] 1. A two-layer optical recording veneer having a thin film of one layer or a plurality of layers required for recording and reproducing information on a pre-format pattern forming surface of a replica substrate, the thin film being inside, and In an optical information recording medium in which a thin film and a replica substrate are bonded together via an adhesive layer, a silicon-based resin that cures at a temperature of 80 ° C. or less is used as an adhesive that constitutes the adhesive layer. Optical information recording medium. 2. The optical information recording medium according to claim 1, wherein a dealcohol type silicone resin is used as the silicone resin. 3. The optical information recording medium according to claim 1, wherein a deoxygen type silicone resin is used as the silicone resin. 4. The optical information recording medium according to claim 1, wherein a deacetic acid type silicone resin is used as the silicone resin. 5. The silicon-based resin according to claim 1, wherein at least two kinds of silicone resins selected from dealcohol type silicone resins, deoxygen type silicone resins and deacetic acid type silicone resins are used. An optical information recording medium characterized by using a mixture. 6. A two-layer optical recording veneer having one or a plurality of layers of thin films required for recording and reproducing information on the surface of a replica substrate on which a pre-format pattern is formed is prepared, and then at least one of them is formed. 80 on the thin film of the optical recording single plate and on the pre-format pattern forming surface of the replica substrate.
A spin coating of a silicon-based resin that cures at a temperature of ℃ or less, then the thin film inside, the two optical recording veneers are adhered, and the two optical recording veneers are concentrically bonded. A method for manufacturing a characteristic optical information recording medium. 7. A two-layer optical recording veneer carrying one layer or a plurality of layers of thin films required for recording and reproducing information on a pre-format pattern forming surface of a replica substrate is manufactured, and then one of the optical recording veneers is prepared. An adhesive is applied in a ring shape on the thin film of the recording veneer, and then the two optical recording veneers are adhered with the thin film inside, and the adhesive is preformatted on the thin film and the replica substrate. A method for manufacturing an optical information recording medium, which comprises uniformly spreading the pattern forming surface and concentrically bonding the two optical recording single plates. 8. The optical information according to claim 7, wherein the adhesive is applied in a ring shape on a circumferential region that bisects the area of the replica substrate into an inner peripheral portion and an outer peripheral portion. Recording medium manufacturing method. 9. The method for manufacturing an optical information recording medium according to claim 7, wherein the adhesive is the silicone resin according to any one of claims 1 to 5.