JPH0281341A - Manufacture of information recording disk - Google Patents

Abstract

PURPOSE:To manufacture the disk easily with preferable workability and to prevent oxidation and corrosion of the information recording layer by applying a resin solution on the whole surface of a transparent plastic substrate on which a recording layer is formed and forming a light-transmitting moisture- proof protective layer on the whole surface by drying or curing the binder solution. CONSTITUTION:The information recording layer 2 is formed on the light- transmitting plastic substrate 1 by vapor deposition, for example. Then Fluorocoat EC-104 is applied wholly on the substrate with the formed recording layer 2 by immersing, and then dried at room temp. to form the light- transmitting moisture-proof protective film 7. As Fluorocoat EC-104 used to form the light-transmitting moisture-proof film 7 is quick-drying, taking several ten seconds to become tack free and has low viscosity and nonsticking property, it gives easily a homogeneous thin film. Thus, the manufacture processes can be decreased and simplified. The protective film prevents permeation of water or the like and oxidation and corrosion of the information recording layer. The obtained recording disk shows no warpage and can be used stably for recording, reproducing and erasing for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing an information recording disk used in an optical information recording/reproducing/erasing device.

[Conventional technique WI] Fig. 3 is a sectional view showing a conventional information recording disk disclosed in, for example, Japanese Patent Application Laid-Open No. 60-115037. (2) is a translucent plastic substrate formed on the negative side of the translucent plastic substrate (1), for example, T b Fe
The information recording layer (3) is composed of a Co magnetic layer.
2) a moisture-resistant protective layer formed on, for example, SiN, and (4) an information recording layer on a light-transmitting plastic substrate (
2) and the moisture-resistant protective layer (3) is formed on the opposite side from the surface on which the moisture-resistant protective layer (3) is formed.
It is a moisture protective layer (5) is an information recording layer formed on the top and bottom of a plastic substrate (2), a moisture resistant protective layer (3)
, (4) is a moisture-resistant sealant made of, for example, an ultraviolet curable resin.

Information recording discs can be recorded, reproduced and erased in a long-term, leap-stable manner.
It is also necessary to stably retain the recorded information. However, the metal film used for the information recording layer (2) is subject to corrosion due to oxidation. In addition, for discs with only an information recording layer formed on the substrate, if the substrate is made of plastic, warping as shown in Figure 4 occurs under high humidity due to the influence of moisture absorption, and the optical signal during recording, reproduction, and erasing. This causes optical path deviation and the information becomes unreliable. Figure 4 is a characteristic diagram showing the change in warpage over time of a disc that has not been subjected to the moisture-proofing treatment described above under high humidity (90% RH), where the vertical axis represents warpage (mrad) and the horizontal axis represents the time (hour), and the characteristic curve (a) is 60℃,
(b) is at 40°C, and (C) is at 20°C. Therefore, as in the conventional example shown in Fig. 3, the moisture-resistant protective layer (3) is used to prevent moisture from the atmosphere.
4) prevents moisture from penetrating the plastic substrate (1), and the moisture-resistant sealant (5) prevents moisture from entering from the end surface.

[Problems to be Solved by the Invention] A conventional information recording disk is constructed as described above, and an information recording layer (2) is provided on the negative side of a plastic substrate (1) in order to block moisture in the atmosphere. and moisture-resistant protective layer (3)
A moisture-resistant protective layer (4) was separately formed on the surface opposite to the surface on which the information recording layer (2) was formed, and then a moisture-resistant sealant (5) was provided. Therefore, not only is the manufacturing process many and complicated, but also moisture etc. seeps in from the boundary, resulting in
There were problems in that oxidation and corrosion of the information recording layer (2) and warping of the substrate occurred.

This invention was made to solve the above-mentioned problems, and it simplifies the manufacturing process by reducing the number of manufacturing steps.It also prevents the penetration of moisture, oxidation and corrosion of the information recording layer, and improves the flexibility of the disk. An object of the present invention is to provide an information recording disk that can perform recording, reproduction, and erasure in a long-term, leap-stable manner without causing any problems.

[Means for Solving the Problems] A method for manufacturing an information recording disk of the present invention is to apply a resin solution all over a transparent plastic substrate on which an information recording layer is formed, and dry or harden the resin solution to make it transparent. A moisture-proof protective film is formed on the entire surface.

[Function] In this invention, by using, for example, a quick-drying moisture-proof coating agent as the resin solution, a good light-transmitting moisture-proof protective film can be easily formed over the entire disc by simply dipping and drying at room temperature. be able to. Since a single light-transmitting moisture-proof protective film is simply formed on the entire surface, the number of steps is reduced, and there are no boundaries, which blocks moisture from entering from outside and from the boundaries. Therefore, performance deterioration due to oxidation and corrosion of the information recording layer can be prevented, and warpage due to moisture absorption of the plastic substrate can be prevented.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a cross-sectional view showing an information recording disk obtained according to an embodiment of the present invention. In figure 0, (1) is a translucent plastic substrate, in this case a polycarbonate resin substrate, and (2) is an information recording layer. , in this case T bF eC
o The magnetic layer (7) is a translucent moisture-proof protective film formed on the entire surface to cover the translucent plastic substrate (1) and the information recording layer (2). resin dissolved in a nonflammable, quick-drying solvent)
This is a fluorocarbon resin film formed by applying Fluorocor EC-104 (manufactured by Asahi Glass Co., Ltd.) and drying it.

The information recording disk of this embodiment is first formed by depositing an information recording layer (2) on a transparent plastic substrate (1), for example.
) on which a zero-order information recording layer (2) is formed.
Fluorocoat EC-104 is applied to the entire surface of 1) by a dipping method and dried at room temperature to form a translucent moisture-proof protective film (7). Fluorocoat EC-104, which was used to form this translucent moisture-proof protective film (7), is quick-drying, drying to the touch in a few tens of seconds, and has a low viscosity, so it drains easily and can easily form a uniform thin film. It will be done.

In addition, as in the conventional example, moisture-resistant protective layers (3), (4) and sealing material (
5) A single light-transmitting moisture-proof protective film (7)
Since it is formed to uniformly cover the entire surface of the disk, the number of steps is reduced, and there are no boundaries between the moisture-resistant protective layer (3), (4) sealing material (5), or the like, which prevents moisture from entering from the boundary. This prevents deterioration of performance due to oxidation and corrosion of the information recording layer, and prevents warping of the plastic substrate due to moisture absorption.

The light-transmitting moisture-proof protective film (7) thus formed
shows good moisture resistance, and the warpage of the information recording disk obtained in this example at 60'C high humidity (90$RH) is as shown in the characteristic diagram showing the change in warpage over time in Figure 2. improved. In Figure 2, the vertical axis represents the warpage (mrad) of the information recording disk, and the horizontal axis represents the hour.
).

Furthermore, accelerated tests at 60°C and 90$RH showed good progress, and 100OII? No deterioration in performance or occurrence of corrosion was observed in the leap.

As described above, the information recording disk obtained in this example was not affected by the humidity of the outside air and was highly reliable in that stable recording and reproduction could be performed for a long period of time.

Although the above embodiment may be used as a single-sided information recording disk made of a single sheet, a double-sided disk may be produced by laminating two single sheets.

In that case, it is desirable to form a light-transmitting moisture-resistant protective film after bonding.

In addition to polycarbonate resin, resins such as polyester and acrylic are used as materials for the transparent plastic substrate according to the present invention.

As the information recording layer, in addition to the TbFeCo magnetic layer, TbF
E, GdCo, etc. are used, and are formed by, for example, vapor deposition, sputtering, etc.

As the light-transmitting moisture-proof protective film, one is used that is transparent to the light used during recording, reproduction, and erasing, has sufficient moisture-proofing properties, and does not affect the information recording layer. In addition, materials with low toxicity, nonflammability, and materials that can be used by dipping are easy to handle and are desirable.

[Effects of the Invention] As described above, according to the present invention, a resin solution is applied to the entire transparent plastic substrate on which an information recording layer is formed,
By drying or curing the above resin solution to form a translucent moisture-proof protective film on the entire surface, it can be easily manufactured with good workability, prevents oxidation and corrosion of the information recording layer, does not cause warping, and is highly reliable. This has the effect of providing a high information recording disc.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an information recording disk obtained according to an embodiment of the present invention, FIG. FIG. 3 is a sectional view showing a conventional information recording disk, and FIG. 4 is a characteristic diagram showing changes over time in warpage of a conventional information recording disk not subjected to moisture-proofing treatment. In the figure, (1) is a translucent plastic substrate, (2)
(7) is an information recording layer, and (7) is a light-transmitting moisture-proof protective film. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Figure 1

Claims (1)

[Claims] A method for manufacturing an information recording disk, comprising applying a resin solution to the entire transparent plastic substrate on which an information recording layer is formed, and drying or curing the resin solution to form a light-transmitting moisture-proof protective film over the entire surface.