JPH03203827A - Optical information recording medium and production thereof - Google Patents

Abstract

PURPOSE:To eliminate the deformation by warpage and to obtain the optical information recording medium of a sticking type having high reliability by previously subjecting a base film to shrinking by a heat treatment. CONSTITUTION:A double coated tacky adhesive film 7 of the optical information recording medium of the sticking type, which is formed by sticking a transparent substrate 1 having a recording layer 3 and another plate to be stuck (a transparent substrate 1 having the recording layer 3 or a veneer or the like which is not provided with the recording layer 3) to each other via the double coated tacky adhesive film 7 with the recording layer 3 positioned on an inner side, is formed of the base film 8 which is previously subjected to the thermal shrinking and tacky adhesive agent layers applied and formed on both surfaces of the base film 8. The generation of the warpage on the optical information recording medium is obviated in this way and the reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical information recording medium such as an optical-magnetic disk cartridge, and particularly relates to an optical information recording medium such as an optical-magnetic disk cartridge. A laminated optical information recording medium in which a transparent substrate having a transparent substrate or a veneer without a recording layer, etc.) is laminated with the recording layer inside through a double-sided adhesive film. 2. Method for producing the same It is related to.

[Prior Art] FIG. 7 is a sectional view of a conventional laminated optical information recording medium capable of double-sided recording.

As shown in the figure, an enhancement film 5 is formed on a transparent substrate 51.
2. A recording layer 53 and a reflective film 54 are sequentially formed to form one optical disc 55. Then, two optical disks 55 are bonded together using an adhesive layer 56 with the recording layer 53 inside to form a bonded optical information recording medium capable of double-sided recording.

In the second type of optical information recording medium, the adhesive layer 56 is made of, for example, a liquid adhesive, a hot melt adhesive, or a double-sided adhesive film.

[Problems to be solved by the invention] By the way, when using a liquid adhesive for bonding, it is necessary to control the viscosity of the liquid adhesive, and also to control the application work and the leakage of the applied liquid adhesive. Productivity is poor because it takes time to wipe it off, leave it for the adhesive to harden, and dry it. Moreover, if the optical disks 55 are misaligned with each other during the drying process, the tracking center will shift due to the misalignment of the spindle insertion holes of the bonded double-sided optical disks 55, 55, resulting in rotational imbalance and proper tracking. It has problems such as not being able to

On the other hand, if a hot melt adhesive is used, it does not have the problems of liquid adhesives and can improve production efficiency, but it is not without its drawbacks.

In other words, in the case of hot melt adhesive, the adhesive is
It is heated to about 0° C. to soften and melt, and then applied to the surface of the optical disk 55 opposite to the transparent substrate 51. At this time, the transparent substrate 51 of the optical disk 55 is heated to about 100° C., so the refractive index changes due to the thermal influence on the substrate 51, which is optically unfavorable.

In order to avoid this, a hot melt adhesive is applied on the reflective film 54 of one or both transparent substrates 51 or the protective film formed thereon. There is a method of heating the hot-melt adhesive layer to soften and melt it before overlapping both transparent substrates 51, and then immediately overlapping and bonding both transparent substrates 51 in that state.

However, in the second method, it is necessary to overlap and bond both transparent substrates 51 before the hot melt adhesive in a softened and molten state is cooled and solidified.

Therefore, there is a time limit M until the adhesive is heated and melted and the transparent substrates 51 are stacked, and there is no margin in the bonding process, which causes the occurrence of defective products.

On the other hand, although the method using a double-sided adhesive film does not have the disadvantages of liquid adhesives or hot melt adhesives, it is not without its problems.

In other words, in order to improve the mechanical properties of optical discs, attention is paid to the uniformity of the thickness of the base film and adhesive layer, but when environmental tests such as high temperature, high humidity, and heat cycle tests are performed, optical discs 5
5 is warped, and due to the warped deformation, the ability of the optical head to follow the optical disc 55 during signal recording and reproduction is poor.
There are reliability issues.

It is an object of the present invention to effectively overcome the drawbacks of the conventional technology of the type in which a transparent substrate having a recording layer is bonded to another board to be laminated by using such an open-sided adhesive film, thereby improving reliability. An object of the present invention is to provide an optical information recording medium with high performance and a method for manufacturing the same.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a transparent substrate having a recording layer and another board to be laminated (such as a transparent substrate having a recording layer or a veneer without a recording layer). ) are bonded together via a double-sided adhesive film with the recording layer facing inside.

The double-sided adhesive film is characterized in that it is composed of a base film that has been heat-shrinked in advance and adhesive layers that are coated and formed on both sides of the base film.

In order to achieve the above object, the present invention further provides a bonded optical information recording method in which a transparent substrate having a recording layer and another plate to be bonded are bonded via a double-sided adhesive film with the recording layer inside. In a method for manufacturing a medium.

The double-sided adhesive film is composed of a base film and an adhesive layer coated and formed on both sides of the base film, and the base film material is subjected to shrinkage processing by heat treatment before forming the adhesive layer. It is characterized by the fact that

In order to achieve the above object, the present invention further provides a bonded optical information recording method in which a transparent substrate having a recording layer and another plate to be bonded are bonded via a double-sided adhesive film with the recording layer inside. In the method for producing a medium, the double-sided adhesive film is composed of a base film and an adhesive layer coated on both sides of the base film, and the double-sided adhesive film is punched out into a predetermined shape and size. The base film is characterized by being subjected to a shrinking process by heat treatment.

In order to achieve the above object, the present invention further provides a laminated optical information recording device in which a transparent substrate having a recording layer and another plate to be laminated are laminated via a double-sided adhesive film with the recording 1 inside. In the method for producing a medium, the double-sided adhesive film is composed of a base film and an adhesive layer coated on both sides of the base film, and the transparent substrate having the recording layer and another plate to be laminated are bonded together. By heat-treating the double-sided adhesive film before bonding,
This method is characterized in that the base film is subjected to a shrinking process.

[Function] As mentioned above, in the method of using a curved adhesive film,
When subjected to environmental tests such as high temperature, high humidity, and heat cycle tests, optical information recording media warp, and due to the warped deformation, there is a problem that the optical head has poor tracking ability with respect to the optical disk during signal recording and reproduction.

As a result of various studies regarding the second issue, the inventors of the present invention found that if a laminated optical information recording medium is used at high temperatures or left unattended, the base film constituting the double-sided adhesive film may become uneven. It has been found that the optical information recording medium is warped as a result of thermal contraction. That is, the base film is stretched in its stretching direction and in a direction perpendicular to its stretching direction.

Thermal shrinkage rates vary greatly. Moreover, since a laminated optical information recording medium has a double-sided adhesive film attached to almost the entire surface of the optical information recording medium, if the base film heat-shrinks unevenly, the uneven shrinkage force will affect the optical information recording. It covers almost the entire surface of the medium, resulting in warping of the optically flexible recording medium.

Therefore, in the present invention, the above-mentioned problems are effectively solved by using a base film that has been subjected to shrinkage processing by heat treatment in advance, thereby providing a highly reliable laminated optical information recording medium. .

[Embodiments of the invention] Next, an embodiment of the present invention will be described with reference to one drawing.

FIG. 1 is a perspective view showing a cross section of a part of a double-sided recording type laminated optical information recording medium according to an embodiment, and FIG. 2 is a cross-sectional view of a part of a double-sided adhesive film used for the optical information recording medium. 3 is an exploded perspective view partially cut away to explain the assembly order of the optical information recording medium, and FIG. 4 is a schematic diagram to explain the punching process of the double-sided adhesive film. be.

As shown in FIG. 1, a first enhancement film 2a is formed on a transparent substrate 1, a recording layer 3 made of an opto-magnetic material, and a reflection layer 4. 1 by sequentially forming the second enhancement film 2b and the protective film 5.
A number of optical discs 6 are manufactured.

Then, two optical discs 6 are bonded together with a double-sided adhesive film 7 with the recording layer 3 side facing inside to form a bonded optical information recording medium capable of double-sided recording.

As the transparent group tffl, for example, transparent ceramics such as glass, transparent resin materials such as polycarbonate (PC), polymethyl methacrylate (PMMA), polymethylpentene, and epoxy are used.

As the first and second enhancement films 2a and 2b, a dielectric material such as silicon nitride or aluminum nitride is used, for example.

As the recording layer 3 made of the above-mentioned opto-magnetic material.

For example, Tb-Fe alloy, Tb-Fe-Co alloy, Tb-
Fe-Co-Nb alloy, Tb-Fe-Nb alloy, Gd-
Tb-Fe-Nb alloy, Gd-Tb-Fe-Co
-N l) Alloy, Gd-Tb-F=-alloy, Dy-Fe
Alloy, Mn-Cu-B1 alloy (crystalline), Gd-τb-
Fe-Ge alloy, Gd-Tb-Fe-Ge alloy, Ge-
Co alloy, Gd-Tb-Co alloy, G d -T b-
Co-Nb alloy.

Mixture of Tb-Fe alloy and Gd-Fe alloy, Tb-Fe
Mixture of alloy and Gd-Fe-Co alloy, Tb-Dy-F
e-Co alloy, Tb-Ni-Fe alloy, Dy-Fe-G
Amorphous alloys are mainly used, such as d-Co alloys.

Recording materials for write-once optical recording media include Te and Te-5.
e-Pb alloy, Te-C alloy, Te-Te○-Te
An O2 laminated film or an organic dye having recording ability can be used.

As the reflective film 4, for example, aluminum or an alloy of aluminum and nickel, aluminum and titanium, aluminum and chromium, aluminum and manganese, or aluminum, nickel and titanium is used.

The protective film 5 is formed of a material such as a photocurable resin such as an ultraviolet curable resin, an electron beam curable resin, or an infrared curable resin, silicon maroxide, aluminum dioxide, stainless steel, or ceramic.

The double-sided adhesive film 7 is composed of a base film 8 and an adhesive layer 9 coated on both sides of the base film 8.

As the base film 8, a synthetic resin film such as polyimide, polyethylene terephthalate, polyamide, etc. is used, and among them, the polyimide film is prized for its excellent heat resistance. The appropriate thickness of the base film 8 is 20 to 100 μm.

The adhesive layer 9 may be made of, for example, silicone resin,
Polyvinyl alcohol, polyacrylamide, polymethylene oxide, polyacrylic acid.

Synthetic adhesives such as polyethylene sulfonic acid, phosphorylated polyvinyl alcohol, polyethyleneimine hydrochloride, and polyvinylpyridine hydrochloride are used.

The thickness of this adhesive layer 9 is suitably 25 to 50 μm,
The thicknesses of the base film 8 and adhesive layer 9 are strictly controlled.

As shown in FIG. 1, the length of the screen adhesive film 7 is designed to be slightly shorter than the lengths of the substrate 1 and the protective film 5, so that some of the adhesive does not come from the edge of the substrate 1 etc. A recess 10 is formed around the periphery so as not to protrude.

As shown in FIG. 2, the double-sided adhesive film 7 is punched out into a disk shape having a through hole 11 in the center. and the third
As shown in the figure, 1 double-sided adhesive film 7 is placed between 2
Two optical discs 6 are placed with the recording layer 3 side on the inside, and the substrate 1
Attach them so that they are on the outside.

The base film 8 of the double-sided adhesive film 7 is shrink-processed by heat treatment at least before the optical disc 6 is bonded thereto, thereby removing internal distortion of the base film 8. There are timings for performing the second shrinkage process, such as the first timing, and the timing is appropriately selected from these timings.

Since the material of the base film 8 is usually in the form of a roll, it is heat-treated in advance in that state.

1. Immediately before applying the adhesive to the base film 8, heat the base film 8 by passing it through a high temperature place (see Figure 5 below). Punching the double-sided adhesive film 7 into a predetermined shape and size. Heat treated before.

(2) Before bonding the optical disc 6 together, the disc-shaped double-sided adhesive film 7 is heat-treated.

FIG. 4 is a schematic diagram illustrating the process of punching out the double-sided adhesive film 7. As shown in the figure, the open-sided adhesive film 7 is continuously punched out from a wide sheet-like body 12. Since the heat shrinkage rate of this sheet-like body 12 is different between the X direction and the Y direction, the shrinkage process is performed by heat treatment to remove the internal distortion of the base film 8 as described above. The timing may be such that the sheet-like material 12 is heat treated and then punched out into a disk shape.The timing of step 1) 1) The double-sided adhesive film 7 may be subjected to a second roasting treatment after being punched out into a disk shape. (Rei's timing above).

Furthermore, as shown in FIG. 5, the material 13 of the base film 8 wound into a coil is sequentially unrolled,
Adhesive is applied to the upper and lower surfaces by the roller 14, and the dryer 1
In the step of drying in step 5 to form the adhesive layer 9, the base film 8 can be heat-treated by the heater 16 before the adhesive is applied by the roller 14 (timing 2 above).

The temperature during the heat treatment is about 80 to 100°C, and the time is related to the temperature, but it is suitable to be about 30 minutes to 1 hour.

FIG. 6 is a partially sectional perspective view of a double-sided recording type laminated optical information recording medium according to a second embodiment of the present invention.

As shown in the figure, a base film 17 made of, for example, polytetrafluoroethylene (PTFE) is disposed on the transparent substrate 1.
A recording layer 3 is formed through the. These two optical disks 6 are bonded together via an inner circumferential spacer 18 and an outer circumferential spacer 19 using an open-face adhesive film 7 similar to that of the previous embodiment. The inner spacer 18 and the outer spacer 19 form a gap 20 between the upper and lower recording layers 3.3.

In the above embodiment, the case of an optical information recording medium capable of double-sided recording has been described, but the present invention can also be applied to an optical information recording medium capable of single-sided recording in which one side is a single plate.

[Effects of the Invention] The present invention has the above-mentioned structure, and by using a base film that has been shrink-processed by heat treatment, deformation due to warping can be effectively eliminated and highly reliable lamination can be achieved. It is possible to provide a type of optical information recording medium.

[Brief explanation of drawings]

1 to 6 are for explaining the present invention in detail, and FIG. 1 is a cross-sectional view of a part of a double-sided recording type laminated optical information recording medium according to the first embodiment. FIG. 2 is a perspective view of a part of the double-sided adhesive film used in the optical information recording medium, and FIG. 3 is a partial cross-sectional view for explaining the assembly order of the optical information recording medium. FIG. 4 is a schematic diagram for explaining the punching process of the double-sided adhesive film; FIG. 5 is a schematic diagram for explaining the process of applying adhesive to the base film; The figure is a partially sectional perspective view of a double-sided recording type laminated optical information recording medium according to the second embodiment of the present invention, and FIG. 7 is a conventional laminated optical information recording medium capable of double-sided recording. FIG. 2 is a cross-sectional view of a recording medium. DESCRIPTION OF SYMBOLS 1... Transparent substrate, 3... Recording layer, 6... Optical disc, 7... Double-sided adhesive film, 8... Base film, 9 ...Adhesive layer, 12 ... Sheet-like body, 13 ...
・Material, 16... Heater. Figure 3 Figure 2 4 5

Claims (6)

[Claims] (1) In a laminated optical information recording medium in which a transparent substrate having a recording layer and another plate to be laminated are laminated via a double-sided adhesive film with the recording layer inside, the double-sided adhesive film is An optical information recording medium comprising a heat-shrinkable base film and an adhesive layer coated on both sides of the base film. (2) The optical information recording medium according to claim (1), wherein the other bonded plate is a transparent substrate having a recording layer. (3) The optical information recording medium according to claim (1), wherein the other bonded plate is a single plate on which no recording layer is formed. (4) A method for manufacturing a laminated optical information recording medium in which a transparent substrate having a recording layer and another plate to be laminated are laminated via a double-sided adhesive film with the recording layer inside, wherein the double-sided adhesive The adhesive film is composed of a base film and an adhesive layer coated on both sides of the base film, and the base film material is subjected to shrinkage processing by heat treatment before forming the adhesive layer. A method for manufacturing a featured optical information recording medium. (5) A method for manufacturing a laminated optical information recording medium in which a transparent substrate having a recording layer and another plate to be laminated are laminated via a double-sided adhesive film with the recording layer inside, wherein the double-sided adhesive The double-sided adhesive film is composed of a base film and an adhesive layer coated on both sides of the base film, and the double-sided adhesive film is heat-treated before being punched into a predetermined shape and size to shrink the base film. 1. A method for manufacturing an optical information recording medium, characterized by subjecting it to processing. (6) A method for manufacturing a laminated optical information recording medium in which a transparent substrate having a recording layer and another laminated board are laminated via a double-sided adhesive film with the recording layer inside, wherein the double-sided adhesive The double-sided adhesive film is composed of a base film and an adhesive layer coated on both sides of the base film, and the double-sided adhesive film is heat-treated before bonding the transparent substrate having the recording layer and another board to be laminated. A method for manufacturing an optical information recording medium, characterized in that the base film is subjected to a shrinking process.