JPH0449541A - Production of optical information recording medium - Google Patents

Abstract

PURPOSE:To obtain uniform layers with good accuracy by using a gravure printing method at the time of forming a protective layer and/or flaw preventive layer consisting of a UV curing type resin on an optical disk and an optical card. CONSTITUTION:An optical recording layer is formed on a resin substrate and a semi-finished product 1 laminated with the protective layer and protective film is placed on a transporting machine 6. A UV curing type resin liquid 7 which is measured by a gravure roll 2 and is transferred to an offset roll 3 is transferred to the substrate surface of the semi-finished product 1 when the semi-finished product 1 sent by a transporting machine 6 and the offset roll 3 are brought into pressurized contact. The product is thereafter dried by a hot wind dryer 4 by which the solvent of the applied UV curing type resin liquid 7 is removed. The UV curing type resin is irradiated with light by a UV irradiating device 5 and is thereby cured. The optical recording medium of a low cost having the high productivity and layer thickness accuracy is obtd. without selecting the resin according to this constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is applicable to video discs and digital audio discs (eg, compact discs).

Records digital signals such as still images and document files,
The present invention relates to a method of manufacturing an optical information recording medium such as an optical disk or an optical card to be reproduced.

[Prior Art] In general, optical discs are considered promising as information media because they have advantages such as high information density and low noise, and video discs.

It has been commercialized as a digital audio disc. Furthermore, since optical cards have similar advantages, they are being commercialized as medical management cards and ID cards.

FIG. 4 is a schematic diagram showing a compact disc which is a conventional general digital audio disc. In the compact disc shown in the figure, a PGM-converted digital signal is recorded in the form of a bit string on a resin substrate, and is reproduced by a semiconductor laser beam.

In FIG. 4, 14 is a disk, 12 is a resin substrate, 1
Reference numeral 5 indicates a recording bit of a bit string-shaped digital signal section carved on the resin substrate 12, 11 indicates a reflective layer formed on the surface of the recording bit, IO indicates a protective layer provided on the reflective layer 11, and 9 indicates a protective layer. 10 is a label printing layer provided, 16 is a semiconductor laser beam for reproduction, and 13 is a scratch prevention layer provided on the opposite side of the resin substrate 12.

In FIG. 4, the reflective layer 11 is used to reproduce digital signals, the protective layer 10 is used to protect the reflective layer, the label printing layer 9 is used to identify discs, and the scratch prevention layer is used to prevent scratches on the resin substrate. Each is necessary for prevention.

Conventionally, the method shown in FIG. 2 has been common as a method for forming a protective film or a scratch prevention layer on a resin substrate provided with a recording layer or a reflective layer.

In FIG. 2, reference numeral 1 indicates an optical disk or an optical card before forming a protective film or a scratch prevention layer, and is a semi-finished product in which an optical recording layer and the like are formed on a resin substrate. 17 indicates a spin coater;
8 is a rotating part of this spin coater 17, 7 is an ultraviolet curing resin liquid forming a protective layer or a scratch prevention layer, 19
is a dispenser that supplies this ultraviolet curable resin liquid and is a resin supply nozzle.

In FIG. 2, the ultraviolet curable resin liquid 7 is dropped onto the semi-finished product 1 and is uniformly spread by the rotating part 8, so that the ultraviolet curable resin liquid 7 is applied onto the semi-finished product 1 placed on the rotating part 8. After the liquid 7 is applied, it is cured by irradiating light with a curing device (not shown) to form a protective layer or a scratch prevention layer.

In addition, when forming only a protective layer, JP-A-1-17
By the method disclosed in Japanese Patent No. 3341, that is, by a screen printing apparatus as shown in FIG.
It is formed by applying the ultraviolet curable resin liquid 7 with a dispenser 21 such as a squeegee that spreads the ultraviolet curable resin liquid 7 through a screen 20 having a mesh that allows the ultraviolet curable resin liquid 7 to pass through.

[Problems to be Solved by the Invention] However, the conventional method for forming a protective layer or scratch prevention layer using a spin coater has problems such as long production times and high equipment costs. have. Furthermore, since the layer is uniformly formed over the entire surface, it is not possible to perform patterning and it is not possible to form an arbitrary shape. Further, although it is possible to form a uniform layer on a circular workpiece, there are drawbacks such as poor stability on a rectangular workpiece such as an optical card.

On the other hand, in the method of forming a protective layer or a scratch prevention layer using a screen printing method, there is a limit to the viscosity of the ultraviolet curable resin liquid, and a low-viscosity resin liquid cannot be used. Therefore, there were drawbacks such as poor leveling properties and insufficient layer precision (layer thickness).

The present invention has been made in order to improve the drawbacks of such conventional techniques, and is a method for forming a protective layer and/or a scratch prevention layer of an ultraviolet curable resin on an optical disk or an optical card, using the gravure printing method. By using this technology, it is possible to perform buttering, and the viscosity range of the ultraviolet curable resin used can be widened, allowing uniform layers to be formed with high precision (short production time) and low equipment costs (optical information recording media). The purpose of this invention is to provide a method for manufacturing.

[Means for Solving the Problems] That is, the present invention provides a resin substrate having a recording layer or a reflective layer on its surface, and a protective layer is formed on the side of the recording layer or the reflective layer, and a scratch prevention layer is formed on the opposite side. In a method for manufacturing an optical information recording medium, an ultraviolet curable resin liquid is coated on the recording layer or reflective layer side and/or the opposite side of a resin substrate by a gravure printing method, and then the ultraviolet curable resin is cured by irradiation with light. This is a method of manufacturing an optical information recording medium, which comprises forming a protective layer and/or a scratch prevention layer.

[Function] According to the present invention, when a protective layer of an ultraviolet curable resin is formed on the recording layer or reflective layer side of a resin substrate provided with a recording layer or a reflective layer, and a scratch prevention layer is formed on the opposite side, By using the gravure printing method, buttering is possible, the viscosity range of the ultraviolet curable resin used can be widened, a uniform layer can be formed with high precision, the production time is short (the equipment cost is low, and the optical information Recording media can be manufactured.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 FIG. 1 is an explanatory diagram showing an example of the method for manufacturing an optical information recording medium of the present invention. Figure 1 shows a method for manufacturing an optical card, in which 1 is a semi-finished product with an optical recording layer etc. formed on a resin substrate, and 2 is the layer thickness of a scratch prevention layer formed from an ultraviolet curable resin liquid 7. 3 is an offset roll that is once transferred from the gravure roll 2; 4 is a hot air dryer that dries the solvent contained in the ultraviolet curable resin liquid 7; 5
is an ultraviolet ray irradiation device for curing the ultraviolet curable resin, 6 is a conveyor for transporting these works, and 7 is an ultraviolet curable resin liquid that forms a scratch prevention layer.

In the figure, first, a semi-finished product l (not shown) in which an optical recording layer is formed on a resin substrate and a protective layer and a protective film are laminated thereon is placed on a conveyor 6. On the other hand, the ultraviolet curing resin liquid 7 quantified by the gravure roll 2 and transferred to the offset roll 3 is applied to the substrate of the semi-finished product 1 when the semi-finished product 1 sent by the conveyor 6 and the offset roll 3 are pressed together. transferred to the surface. Thereafter, the semi-finished product 1 is dried in a hot air dryer 4 to remove the solvent of the applied ultraviolet curable resin liquid 7, and then is irradiated with light in an ultraviolet irradiation device 5 to cure the ultraviolet curable resin. .

The scratch prevention layer of the optical card produced by the method of the present invention has a uniform layer thickness of 3 to 5 pm and no pinholes.

There is no uneven thickness. It also had good adhesion to the resin substrate, and good results were obtained in the cross-cut tape peel test. Furthermore, in the aging test at 60°C and 95HR%, good results were obtained both optically and physically (warping, peeling, etc.).

In addition, the production time is a layer forming speed of 0.5 seconds/sheet,
10 seconds per sheet compared to the conventional spin code method, which takes 5 to 10 seconds per sheet.
An improvement in productivity of ~20 times was obtained.

Although polymethyl methacrylate (PMMA) was used for the resin substrate, a wide range of materials such as polycarbonate (PC) can be used as long as it is optically transparent and has low birefringence. The optical recording layer was coated with a polymethine dye, but a chalcogen vapor deposited film or the like may also be used.

Although epoxy type resin was used as the ultraviolet curable resin, a wide variety of other types such as acrylic type and silicone type can be used.

Embodiment 2 In addition to the formation of a scratch prevention layer for an optical card, as another embodiment of the present invention, it is possible to form a protective layer or a scratch prevention layer for a digital audio disk, or to form a protective layer or a scratch prevention layer for an optical disk. Also, layers can be formed in the same manner as in Example 1.

[Effects of the Invention] As explained above, according to the present invention, buttering is possible by forming a protective layer and/or a scratch prevention layer of an ultraviolet curable resin by a gravure printing method using a gravure roll. This has the advantage that it is possible to obtain a low-cost optical recording medium with good productivity, high layer thickness accuracy, and improved performance and stability, regardless of the type of ultraviolet curable resin used.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the method for manufacturing an optical information recording medium of the present invention, FIG. 2 is an explanatory diagram of a spin coater representing a conventional technique, and FIG. 3 is an explanatory diagram of a screen printing method representing a conventional technique. The explanatory diagram and FIG. 4 are schematic diagrams showing a compact disc which is a conventional general digital audio disc. 1... Semi-finished product 2... Gravure roll 3... Offset roll 4... Hot air dryer 5... Ultraviolet irradiation device 6... Conveyor machine 7... Ultraviolet curing resin liquid 8...・Rotating part 9...Label printing layer lO...Protective layer ll...Reflection layer 12...Resin substrate 13...Scratch prevention layer 14...Disc 15...Recording bit 16... Semiconductor laser beam for reproduction 17...Spin coater 18...Fixing part of screen coater 19...Resin supply nozzle 20...Screen 21...Dispenser

Claims (1)

[Claims] A method for manufacturing an optical information recording medium in which a protective layer is formed on the side of the recording layer or reflective layer of a resin substrate provided with a recording layer or a reflective layer on the surface thereof, and a scratch prevention layer is formed on the opposite side. After coating an ultraviolet curable resin liquid on the reflective layer side and/or the opposite side by gravure printing, it is cured by irradiating light to form a protective layer of ultraviolet curable resin and/or
Or, a method for producing an optical information recording medium, which comprises forming a scratch prevention layer.