JPS6314339A - Optical recording medium - Google Patents

Abstract

PURPOSE:To improve the storage stability by forming a layer formed by scattering a substance expanded by heating whose deformed state is maintained by succeeding cooling into a rubber elastic body onto a light reflecting layer so as to eliminate the deterioration in the recording characteristic due to oxidation and corrosion. CONSTITUTION:A light reflecting layer 6 is formed on the base 5 and the layer 9 formed by scattering the substance 7 which is expanded by heating and whose deformed state is maintained by the succeeding cooling in the rubber elastic body 8 is formed on the light reflecting layer 6. As the base 5, an organic such as a resin is used or a metallic plate whose surface is in the mirror surface state while using itself as the base 5 and the light reflecting layer 6 in common is used. Since modification such as oxidation or corrosion does not take place different from a metallic thin film, the deterioration in the recording characteristic is not caused and the storage stability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an optical recording medium suitable for heat mode recording, and more particularly to an optical recording medium that does not cause deterioration in recording characteristics and has excellent storage stability.

[Prior art and its problems J Optical recording media are formed on a substrate such as glass or plastic, and laser beams are focused on a spot according to information to generate heat due to melting, evaporation, aggregation, expansion, etc. It is used to record by deforming it.

Conventionally, as such optical recording media, metal thin films such as Te, Bi, A1, etc. are used as heat mode recording media, and as shown in FIG. 3, these metal thin films are deposited on a substrate l such as glass or plastic. It is known that the recording layer 2 is formed of:

Here, when glass is used as the substrate 1, the glass is
Although it has the advantage of low gas permeability, it has a high thermal conductivity compared to acrylic resins, and is inconvenient in handling, such as being vulnerable to mechanical shock.

For this reason, plastics such as acrylic resins are now preferably used as the substrate 1.

However, since plastics such as acrylic resin have a relatively high gas permeability, generally, as shown in FIG. It has a sealed air sandwich structure. However, it was still easy for water vapor, oxygen, and other gases to enter the interior where the recording layer 2 existed, and the recording medium was likely to be oxidized and corroded (this caused deterioration during recording).

OBJECT OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide an optical recording medium in which the recording characteristics do not deteriorate due to oxidation or corrosion.

"Summary of the Invention" The optical recording medium of the present invention includes a rubber-like elastic material that is thermally expanded and deformed by heating and can maintain the deformed state even by subsequent cooling, on the light reflective layer of a substrate having a light reflective layer. It is characterized by the formation of layers dispersed throughout the body.

In the optical recording medium of the present invention, when a part of its surface is heated by applying light from a xenon lamp, for example, the thermally expandable substance expands and deforms in the heated part, and the rubber-like elastic material around it expands and deforms. transform.

The expansion and deformation state caused by this substance is maintained even after cooling, and a bulge is formed on the surface of the irradiated area. The bulged portion has different states of refraction, diffraction, and reflection compared to the unirradiated portion of the xenon lamp. That is,
There is a difference in light transmittance between the bulge and other parts. Here, when this optical recording medium is irradiated with light for reproduction, the amount of reflected light reflected from the light reflection layer and returned is different between the dazzled portion and the unglazed portion. Therefore, desired recording can be performed by irradiating this optical recording medium with light and applying thermal energy greater than the -window to cause deformation on the surface of the medium. In addition, in this recording method that uses deformation of a rubber-like elastic body, unlike metal thin films, there is no oxidation, corrosion, or other changes, so there is no deterioration during recording and storage stability is improved. Gazekiru.

Embodiment J of the Invention The optical recording medium 4 according to the present invention has a light reflecting layer 6 formed on a substrate 5, as shown in FIG.
A layer 9 is formed in the soil, in which a rubber-like elastic body 8 is made up of a substance 7 which is expanded and deformed by heating and maintained in this deformed state or by subsequent cooling.

Here, the substrate 5 may be any organic material such as resin, but it may be a metal plate whose surface is mirror-finished and which serves as the substrate 5 and the light reflection layer 6, for example, an AI substrate used in magnetic disks, etc. It may be.

Further, as the light reflecting layer 6, Au, Ag, Ru, Rh
In addition to white metals such as , pb, Os, Ir, and Pt7i, metals such as Ni, Ti, Cu, Cr, and AI, alloys that combine two or more of these metals, and in general, metals that are non-containing with these metals and alloys. Although a combination of a metal element and a metal element is preferable, other materials that can be used as the light-reflecting layer 6 are not limited to these examples.

Further, as the material 7 that can be thermally expanded and deformed by heating and maintain this deformed state even by subsequent cooling, it is preferable to use a thermally expandable thermoreversible resin, such as a thermoplastic resin containing a compound with a low temperature point. , and any other method that meets the purpose of the present invention is not limited to this example. In this case, the thermoplastic resin is preferably a fine powder of 1 um or less.

Generally speaking, it is preferable that the rubber-like elastic body 8 has a high light transmittance and is transparent.

Specifically, for example, styrene rubber, butadiene rubber, nitrous rubber, butyl rubber, acrylic rubber, urethane rubber, silicone rubber, fluororubber, chlorosulfonated polyethylene, ethylene vinyl acetate copolymer, chlorinated polyethylene, boroisobutylene, alphine rubber. Synthetic rubbers such as , polyester rubber, epichlorohydrin rubber, chlorinated butyl rubber, nitrile isoprene rubber, and thermoplastic styrene rubber can be used, but are not limited to these examples. Any rubber-like elastic body that deforms when thermally expanded and deformed by heating may be used.

Next, the state of change due to heat in the optical recording medium 4 according to the present invention will be explained with reference to FIG.

First, a xenon lamp 10 is placed on a part of the surface of the optical recording medium 4.
When the substance 7 in the rubber elastic body 8 is irradiated with light 11 and heated, the substance 7 in the rubber elastic body 8 expands and deforms, thereby deforming the rubber elastic body 8 around it. Thereafter, when the xenon lamp 9 is turned off and cooled to room temperature, the substance 7 maintains the deformed state due to thermal expansion that occurred when it was irradiated with the light 11 of the xenon lamp 10, producing a bulge 12 on the surface. . This bulge 1
Since the surface state and internal state of the portion 2 are different from those of the portion not irradiated with the light 11, the optical properties such as refraction, diffraction, and reflection states are different. When recording and reproducing light is applied to this part, the angle of incidence of the light changes due to the bulge 12, and inside the bulge 12, the light is refracted, reflected, etc. in a complicated manner and is scattered. Bulge 1
The amount of light that reaches the light reflecting layer 6 located under the light reflecting layer 2 and is reflected by the light reflecting layer 6 is different from the unirradiated portion of the light 11 of the xenon lamp 10. That is, the light 11 of the xenon lamp 10
In the irradiated part of the bulge 12 and the unirradiated part,
When recording and reproducing light is irradiated, the amount of light reflected from each part will be different.

The magnitude of the change in the reflectance of this light corresponds to the degree of change in the substance 7, so it may depend on the thermal energy irradiated onto the optical recording medium 4, that is, the wavelength, intensity, or irradiation time of the light. Rubber bullets forming the recording medium 4
It varies depending on the type of object 8 and substance 7.

Example 1 Made of polymethyl methacrylate, one side is 5 cm and the thickness is 1
．． A 0.08 mm thick AI film was formed as a light reflective layer 6 on a 2 mm thick substrate 5 by vacuum deposition. An optical recording medium 4 is formed on this light reflective layer 6 by dispersing fine powder of a copolymer of vinylidene chloride containing isobutane and having a size of I um or less in Hypalon, and forming a film to a thickness of 3 um. was created.

When a part of the obtained optical recording medium 4 was irradiated with semiconductor laser light having a wavelength of 820 nm and an output of 20 mν, the irradiated area became cloudy and the light reflectance decreased compared to the unirradiated area. When this cloudy area is observed under a microscope, it is found that the copolymer of vinylidene chloride containing isobutane near the surface of the irradiated area is thermally expanded as if it were generating bubbles, and a bulge 11 is formed on the surface of the optical recording medium 4. It was alive.

The optical recording medium 4 recorded in this way was heated at 70°C185%R.
I left it in an H atmosphere for 20 days, but the custom record did not change at all.

Example 26 Example 1. Instead of a substrate with an AI reflective film in
Example 1 using an AI substrate with a mirror surface. When irradiated with semiconductor laser light under the same conditions as in Example 1.
A similar effect was obtained.

"Effects of the Invention" As explained above, according to the present invention, the light reflecting layer of the substrate having the light reflecting layer is thermally expanded and deformed by heating.
Since the optical recording medium is constructed by forming a layer in which a substance that can maintain the deformed state even after subsequent cooling is dispersed in a rubber-like elastic body, the recording characteristics do not deteriorate due to oxidation or corrosion, and storage stability is achieved. can improve sex.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the optical recording medium according to the present invention, FIG. 2 is a sectional view showing how the optical recording medium of FIG. 1 changes due to heat, and FIG. 3 is a sectional view of a conventional optical recording medium. FIG. 4 is a partially cutaway perspective view showing a conventional optical recording medium having a sandwich structure. In the figure, 4 is an optical recording medium, 5 is a substrate, 6 is a light reflective layer, 7 is a material that thermally expands upon heating and can maintain its deformed state even after subsequent cooling, 8 is a rubber-like elastic body, and 9 is a layer. , 12
is a bulge. Patent applicant Alps Electric Co., Ltd. Agent
Kuni Miura Daido Shigeru Matsui

Claims (2)

[Claims] (1) On the light reflective layer of a substrate having a light reflective layer, a layer is formed in which a substance that is thermally expanded and deformed by heating and that can maintain the deformed state even by subsequent cooling is dispersed in a rubber-like elastic body. An optical recording medium characterized by: (2) The optical recording medium according to claim 1, wherein the rubber-like elastic body is made of a transparent material.