JPH05114168A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To enable formation of the above-mentioned recording medium to a smaller thickness and to improve productivity as well as to prevent the reflected light from the recording layers of opposite layers by concentrically and continuously providing projecting parts in the outer peripheral parts of a pair of substrates and putting the substrates or sheets of a partition structure by these projecting parts. CONSTITUTION:The recording layers 4 are formed on the substrates 1 having the projecting parts on at least the outer peripheries on the side to be provided with the recording layers. A pair of the substrates 1 formed with the layers 4 are adhered in the form of inserting the hollow substrates or sheets 5 with the layers 4 on the inner side. The parts of the sheets 5 protruding from the outer peripheral end of the substrates 1 are folded. The substrates 1 are pinched or fixed by a fitting fame material 6 on the outer peripheral end face or the folding parts 12 are welded by using ultrasonic waves or a solvent or are fixed by an adhesive. The adverse influence of the reflected light from the recording layers on the opposite surface side on recording and reproducing characteristics is prevented in this way and the formation of the medium to the smaller thickness is possible.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an air sandwich type optical information recording medium.

[0002]

2. Description of the Related Art Conventionally, in an optical disc for recording video, digital information, etc. on a thin film made of a recording material such as metal, chalcogen glass, organic dye, etc., two opposing substrates are provided for the purpose of protecting and preserving the recording layer. , For example, a ring-shaped spacer is adhered between plastic discs to form a space containing only clean air between the discs so as to be integrated, and the recording material is formed on the plastic disc surface facing the space. There is a structure (air sandwich structure) in which a thin film is formed in advance (Fig. 1).
reference). However, when the optical disc is made thinner, the air layer becomes thinner, and the amount of reflection from the recording layer on the facing surface increases,
There is a problem in recording and playback. It is known to use an intermediate plate in an air sandwich type optical disk (Japanese Patent Laid-Open No. 57-56296), and an air sandwich type optical disk using a spacer body hollow as a medium body spacer body middle plate is known. Known (Shokaisho 60-
166828). When the middle plate is used, spacers are required on both sides of the middle plate as shown in FIG. 2, and the productivity is poor. Further, when the spacers are assembled as an inner / outer set, the intermediate plate is used, so that the thickness of the disk becomes large. From the viewpoint of productivity, it is preferable to use the spacer body middle plate spacer as shown in FIG. 3. The spacer of such a mold is usually manufactured by injection molding, but the thickness of the partition is 1 mm or less. It was technically difficult.

[0003]

An object of the present invention is to provide an optical information recording medium provided with a partition structure such as another substrate or a film-like sheet so as to divide the optical information recording portion between the upper and lower substrates into two parts, which can be made thin and has excellent productivity. Another object of the present invention is to provide an optical information recording medium having a structure capable of preventing reflected light from the recording layer which is the opposite layer.

[0004]

According to the present invention, a pair of substrates having at least one substrate having an optical information recording layer inside and a partition structure for dividing the internal space layer between the pair of substrates into two substrates or a film-like sheet ( Hereinafter, in the air sandwich structure type optical information recording medium having a hollow substrate or sheet), the pair of substrates has concentric continuous convex portions at least at the outer peripheral portion of the inner and outer peripheral portions thereof. The optical information recording medium is characterized in that the substrate or sheet having the partition structure is sandwiched between the convex portions.

The substrate having a convex portion used in the present invention is provided with convex portions on the inner and outer circumferences by injection molding, a transfer printing method, etc., and the height thereof is 0.1 to 1 mm, preferably 0.2 to 0. .5
mm, and as a necessary characteristic, a material that is transparent to the laser light used must be used.
Examples of plastics include polyester, acrylic resin, polyamide, polyolefin resin, and phenol epoxy resin.

The material for the hollow substrate or sheet has a thickness of 10 μm to 0.5 mm, preferably 50 μm.
There is no particular limitation as long as it can be thinned in the range of m to 0.1 mm, but preferably the plastic used for the above substrate material can be mentioned. Further, this hollow substrate or sheet is preferably one that does not transmit the laser light used, for example, one whose transmittance is 60% or less, in order to prevent light reflected from the recording layer which is the opposite layer. Examples of the material forming the sheet or the like include ABS resin and colored resin. The hollow substrate, sheet or the like is provided with a central hole at a position corresponding to the central hole of the substrate, and the hole is preferably the same as or larger than the central hole of the substrate.

When the optical information recording portion between the upper and lower substrates is completely partitioned by the hollow substrate or sheet, the atmospheric pressure and temperature of the two spaces change, and the atmospheric pressure and temperature of the two spaces are different from each other. Although this may occur, such a thing is not preferable in terms of mechanical characteristics of the optical information recording medium, and in order to make the gas atmosphere such as temperature and pressure uniform, it is preferable to provide ventilation holes in the hollow substrate or sheet. preferable. The number of the holes is singular or plural, and the size thereof is 0.1 to 5 m.
It may be about m, and the shape is not limited to a circular shape, and an arbitrary shape can be adopted. Furthermore, it is preferable that the ventilation holes are provided outside the data area (usually near the inner peripheral portion of the hollow substrate).

Next, the manufacturing process of the optical information recording medium of the present invention will be described with reference to FIGS. In this manufacturing process, the above-mentioned members are used. A substrate 1 having a convex portion and a central hole 11 on the inner and outer peripheries on the side where a recording layer is provided was manufactured by injection molding, casting, printing transfer method or the like. An information recording layer 4 was formed on each substrate 1. As the recording layer 4, for example, a cyanine-based recording layer,
Organic materials such as naphthoquinone and polymethylene, and T
An inorganic material such as e, In, Se or Te alloy may be used. To form the recording layer 4, spin coating is mainly used for an organic material, and vapor deposition, sputtering or the like is used for an inorganic material.

A pair of substrates 1 having a recording layer 4 is used, and the hollow substrate or the sheet 5 is adhered in such a manner that the recording layer is placed inside and the hollow substrate protrudes from the outer peripheral edge of the substrate 1. Or bend the part of the sheet 5,
As shown in FIG. 4, the outer peripheral end surface of the substrate 1 can be sandwiched and fixed by a fitting frame member 6 that fits with the outer peripheral end surface. Further, the bent portion 12 may be fixed by welding with heat, ultrasonic waves or a solvent, or adhesion with an adhesive.

As shown in FIG. 4, the fixing by the fitting frame material can be performed by a tubular or strip-shaped frame material 6 having the same shape as the base material 1, but in consideration of adhesion and the like, a metal having elasticity is used. It is preferable to use rubber, plastic, or the like. Moreover,
As another mode of the fixing method using the fitting frame member, as shown in FIG. 5, a fitting recess having an arbitrary shape is provided on the outer peripheral end surface of the substrate, and the bent portion 12 is formed by the fitting recess and the fitting frame member. You may pinch and fix.

In order to ventilate the information recording medium of the present invention so that the internal pressure and the external pressure are equal to each other in response to a sudden change in pressure or temperature in the external environment, the inside and outside of the substrate 1 and the hollow substrate or the sheet 5 are exposed. At least one of the peripheral adhesive portions may be provided with an adhesive breaking portion 10 that acts as a ventilation hole,
The width of the adhesive break may be about 0.3 to 5 mm. Such an adhesive break is particularly effective in the case where the substrate has convex portions on both the inner and outer peripheral portions thereof and the hollow substrate or sheet is constituted by one having no vent hole.

[0012]

According to the present invention, it is possible to prevent the adverse effect on the recording / reproducing characteristics due to the reflected light from the recording layer on the opposite surface side, and to make it possible to provide an optical information recording medium with excellent productivity. Become. Further, since the fill-shaped plate having a partition structure that divides the internal space layer between the substrates into two is not exposed to the outside, the recording layer and the fill-shaped material do not come into contact with each other, and the storage reliability is excellent.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a conventionally known optical sandwich type optical information recording medium in which spacers 2 and 3 are sandwiched on the inner and outer circumferences.

FIG. 2 is a vertical cross-sectional view of a conventionally known air sandwich structure type optical information recording medium having a hollow substrate 5 with spacers 2 and 3 sandwiched between the inner and outer circumferences.

FIG. 3 is a vertical sectional view of a hollow substrate integrated with a conventionally known spacer.

FIG. 4 is a vertical cross-sectional view of an optical information recording medium of the present invention in which an end portion of a hollow substrate or a sheet 5 is fixed at an outer peripheral end surface of a substrate with a fitting frame member 6.

FIG. 5 is a vertical cross-sectional view of an optical information recording medium of the present invention in which an end of a hollow substrate or a sheet is bent and fixed by a fitting recess provided on the outer peripheral end surface of the substrate and a fitting frame member.

FIG. 6 is a vertical cross-sectional view of an optical information recording medium of the present invention in which an end portion of a hollow substrate or a sheet is bent and fixed to the outer peripheral end surface of the substrate by welding or adhesion.

FIG. 7 shows a cross-sectional view of the optical information recording medium of the present invention.

[Explanation of symbols]

 1 Substrate 2 Inner Spacer 3 Outer Spacer 4 Recording Layer 5 Hollow Substrate or Sheet 6 Fitting Frame Material 7 Fitting Recessed Material 8 Vent Hole of Hollow Substrate or Sheet 9 Recording Area 10 Adhesive Break 11 Center Hole 12 Bent

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Noboru Sasa 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd.

Claims (7)

[Claims] 1. An air sandwich having a pair of substrates having at least one substrate having an optical information recording layer inside thereof, and a substrate or a film-like sheet dividing the internal space layer between the pair of substrates. In the structural type optical information recording medium, the pair of substrates have concentric continuous protrusions on at least the outer peripheral portion of the inner and outer peripheral portions thereof, and the substrate or sheet is held by the convex portions. An optical information recording medium characterized by being present. 2. The optical information recording medium according to claim 1, wherein the substrate and the convex portion provided on the substrate are integrally molded. 3. The optical information recording medium according to claim 1, wherein the substrate or the film-like sheet that divides the internal space layer between the substrates into two has vent holes at the opposite positions outside the recording layer. 4. The optical information recording medium according to claim 1, wherein the substrate or the film-like sheet that divides the internal space layer between the substrates into two has a transmittance of 60% or less for recording / reproducing light. 5. An end portion of a substrate or a film-like sheet that divides an internal space layer between the substrates into two is fixed by a frame member to an outer peripheral end surface on at least one side of the pair of substrates. The optical information recording medium described. 6. The end portion of a substrate or a film-like sheet that divides the internal space layer between the substrates into two is fixed by welding or adhesion on the outer peripheral end faces of at least one side of the pair of substrates. Optical information recording medium. 7. The substrate has a convex portion on both the inner and outer peripheral portions thereof, and the adhesive portion of the inner or outer peripheral portion of the substrate or the film-like sheet dividing the internal space layer between the convex portion and the substrate into two parts. The optical information recording medium according to claim 1, wherein at least one of the adhesive breaking portions has a function as a ventilation hole.