JPS59171042A - Information recording medium - Google Patents

Abstract

PURPOSE:To prevent stripping and to provide superior durability by subjecting the surfaces of a transparent plastic substrate for an optical information recording medium to electric discharge in an atmosphere of an active or inert gas and by forming a recording layer and a protective layer on the surfaces to increase the adhesive strength of the layers. CONSTITUTION:The surfaces of a transparent plastic substrate of polymethyl methacrylate or the like is subjected to electric discharge in an atmosphere of an active gas such as air or oxygen or an inert gas such as N2 or Ar, and a recording layer of a metal (alloy) such as Te, Zn or Bi, a semiconductor such as Si or Ge, or a combination thereof is formed on one of the surfaces. A scratch resistant protective layer may be formed on the other of the surfaces by coating vinylidene chloride latex or the like. An underlayer may be formed before forming the recording layer. The adhesive strength of the layers to the support is increased by the electric discharge, and an optical information recording medium preventing stripping and surface scratch and having superior durability is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information recording medium on which information is written and/or read using laser light.

Conventionally, there are recording media that use a beam with high energy density, such as a laser beam. In such thermal recording media,
The recording layer has a high optical density and absorbs the high energy density light that is irradiated, causing a local temperature rise, and the irradiated area is affected by a buried or chemical change. Information power ζ is recorded by changing the optical properties of

Such recording media are capable of high-density recording;
It has many advantages such as being able to write and read information at high speed, short access time, and excellent long-term preservation of records.

Generally, recording on such a recording medium is performed by converting the information to be recorded into an electrical time-series signal and scanning the recording medium with a laser beam whose intensity is modulated according to the signal. In this case, there is an advantage that recorded images can be obtained in real time.

As such a recording layer (heat mode recording layer), -
In general, a thin film of Bi, Sn, In, T, etc. (!, metal, semi-metal, or semiconductor) formed by vapor deposition on a glass or transparent plastic substrate is used. .

On the other hand, there is also a type of information recording medium that records information during manufacturing, that is, a reproduction-only information recording medium.In this case, fine irregularities are transferred to the substrate using methane, ξ-, etc. Coat with a highly reflective film.

In addition, during handling or storage of these recording media, scratches may occur on the surface of the recording layer, and foreign matter such as dust may adhere7, which may adversely affect recording and reading. Nisantoichi type (full surface adhesive type) or double
Sandwich type information record Gii? body is used.

From the viewpoint of optical properties, ease of handling, and cost, plastic materials such as polymethyl meth, acrylate, etc. are usually used as substrate materials; however, in the case of such recording media, the recording layer may peel off during handling. For this reason, an undercoat layer is provided on the substrate, but there are various problems with the adhesion between the undercoat layer and the substrate. This problem often occurs in the case of the above-mentioned sand 1-inch type and air-sand Germany type, and the recording layers of the sub-board come into contact with each other during assembly.
Since E'j may peel off, it is desired that the recording layer firmly adhere to the substrate when exposed to temperature.

Furthermore, in order to improve the scratch resistance of the surface of the substrate opposite to the recording layer, a protective layer is provided, but there are also problems with the adhesion between the protective layer and the substrate, especially on the latex tongue. When a water-based material is used, for example, if polymethyl methacrylate is used as a substrate, it is difficult to form a uniform film due to poor filtration, and a good protective layer cannot be obtained.

An object of the present invention is to provide an optical information recording medium having a substrate free from the above-mentioned drawbacks and having improved adhesion to the recording layer, undercoat layer and protective layer.

Another object of the present invention is to provide an optical information recording medium in which the adhesion strength of a sub-substrate is improved when assembled into an air sandwich structure.

The above objects of the present invention are achieved by subjecting one or both surfaces of a transparent plastic substrate to a discharge treatment in an active gas or active i'+ gas atmosphere.

That is, the present invention provides an information recording medium in which a recording layer on which information can be written and/or read by a laser beam is formed on a transparent plastic top substrate, in which at least one surface of the substrate is not active. These two information recording devices are characterized in that they have been subjected to discharge treatment in an inert gas atmosphere.

The present invention will be explained in detail below.

As the plastic substrate used in the present invention, a transparent plastic plate or sheet such as polyethylene terephthalate, polycarbonate, acrylic resin (polymethyl methacrylate, etc.) is used. The thickness of the substrate is generally 0
, 31 or more, particularly 1.0 to 1.5 toughness, and is generally used in a disk shape.

There is no limit to the lunar phase used as the recording layer, and the lunar phase used in the technical field, such as Tll, Zn,
Metals such as In, Sn, Zr, kl, Gtb, Cra:
Bi, As, Sl! First class metalloid: Cre
, E3i, etc., and alloys or combinations thereof. In order to provide a recording layer of these materials on the above-mentioned substrate, it is appropriate to use evaporation, sloping, and thickening.

In the present invention, for the purpose of improving the adhesion with the recording layer, the substrate surface is subjected to a discharge treatment before providing the recording layer or the undercoat layer. When a protective layer is provided on the side of the substrate opposite to the recording layer, in order to improve the adhesion with the protective layer, it is necessary to perform discharge treatment on the substrate before forming the recording layer. However, if adhesion is desired for both the recording layer and the retention layer, it is preferable to subject both surfaces to a discharge treatment before forming the recording layer.

The discharge conditions are preferably 0.01 to 0.5 Torr and a voltage of 500 to 3.0 OOV. The discharge atmosphere may be air, an active atmosphere such as 0□-N2 r AT, or the like.

An inert gas atmosphere is used. The treatment time is from several seconds to several minutes, preferably from 10 seconds to 60 seconds.

When carrying out pretreatment of the recording layer, it is preferable to use the same vacuum chamber used for the treatment in the discharge treatment for vacuum deposition, and immediately deposit the recording layer without leaking the vacuum chamber after the discharge treatment. Note that the voltage used for discharge treatment is direct current, alternating current, or high frequency.

Either is fine.

According to the present invention, the following effects can be achieved.

(1) The density of the recording layer and the substrate is improved by -1. In addition, in the case of an air sandwich (1^ structure) in which the recording layer faces inward, peeling of the recording layer due to contact between the recording layers is less likely to occur.

(2) When an undercoat layer is provided on the recording layer, the adhesion between the substrate and the undercoat layer is improved.

(3) When providing a protective layer for the substrate, the adhesion between the substrate and the protective layer is improved. Furthermore, when a water-based material such as latex is used, the adhesion to a substrate such as 11 serimethyl methacrylate is improved, resulting in a film with uniform thickness.

(4) When preparing the air sandwich type de-r-suf, either insert a swazer into the outer periphery where there is no recording layer and the center 7915 to bond it, or discharge the i%tS portion to remove the adhesive. Improves adhesion.

Example 1 Air pressure of 0.05To on poly'methyl methacrylate substrate
After glow discharge treatment at 2000 V for 20 seconds, the TC was evaporated to 50 OA'', J-, RL,
r=.

When this recording layer was subjected to a peel test using a polyester adhesive tape, it was found that the adhesion was significantly improved compared to the F- layer in which TII was deposited without glow-discharge treatment.

Example 2 N1? Air pressure 0.05 on remethyl methacrylate substrate
Torr, glow discharge treatment at 2000V for 20 seconds fil
After that, vinylidene chloride latex was coated as a protective layer to a thickness of 100 ml using a spin coater, and the film was swollen at 80° C. for 10 minutes. As a result, a protective layer was obtained that exhibited a good coated surface without any scratches. On the contrary, glow release 111
．． Process Q7. CI, ・I saw some large and small rehajiki.

Example 6 Two substrates subjected to the same discharge treatment and vapor deposition as in Example 1 (vapor deposition was not performed on the sprayer part) were bonded using a wire hardening type bonding method via a spacer. An air sandwich type disk was made by bonding the parts 1 and 2 with a compound. As a comparative example, an air sandwich type disk was also made in the same manner without the discharge treatment. When the adhesive strength of the two was compared by twisting, it was found that the one without discharge treatment peeled off easily, but the one with discharge treatment did not peel off and was found to be firmly adhered.

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Claims (1)

[Claims] In an information recording medium having a recording layer on which information can be written and/or read using a laser beam on a transparent plastic substrate, at least one surface of the substrate is subjected to discharge treatment in an active or inert gas atmosphere. An information recording medium characterized by: