JP3115062B2 - Optical information recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, in an optical disk 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 used for the purpose of protecting and preserving the recording layer. For example, by attaching a ring-shaped spacer between plastic discs, a space containing only clean air is provided between the discs and integrated, and the recording material is formed on the plastic disc surface facing this space. There is a structure (air sandwich structure) in which a thin film is formed in advance (FIG. 1).
reference). However, when the optical disk is made thinner, the air layer becomes thinner, the amount of reflection from the recording layer on the opposite surface increases, and the like.
Problems occur in recording and reproduction. It is known that an air sandwich type optical disc uses a medium plate (Japanese Patent Laid-Open No. 57-56296). Known (Showa 60-
No. 166828). When a middle plate is used, spacers are required on both sides of the middle plate as shown in FIG. 2, and the productivity is low. Further, when the spacers are assembled in an inner / outer set, the thickness of the disk becomes large because the middle plate is used. In consideration of productivity, it is preferable to use a spacer-type intermediate plate spacer as shown in FIG. 3, but such a spacer is usually manufactured by injection molding, but the thickness of the partition portion is set to 1 mm or less. That 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 an optical information recording portion between upper and lower substrates into two parts, which can be reduced in thickness and excellent in productivity. It is another object of the present invention to provide an optical information recording medium having a structure capable of preventing reflected light from a recording layer of an opposing layer.

[0004]

According to the present invention, there is provided a pair of substrates having at least one substrate having an optical information recording layer therein, and a substrate or a film-like sheet or the like as a partition structure for dividing an inner space layer between the pair of substrates. (Hereinafter referred to as a hollow substrate or sheet.) In the air sandwich type optical information recording medium having a hollow substrate or a sheet, the pair of substrates has a convex portion continuously and concentrically on at least the outer peripheral portion of the inner and outer peripheral portions. And an optical information recording medium characterized in that a substrate or a sheet having the partition structure is sandwiched between the projections.

The substrate having a convex portion used in the present invention is provided with inner and outer convex portions by injection molding, a mark transfer method or the like, and has a height of 0.1 to 1 mm, preferably 0.2 to 0 mm. .5
mm, and as its required properties, it is necessary that the material be transparent to the laser beam used.
Plastics include, for example, polyester, acrylic resin, polyamide, polyolefin resin, phenol epoxy resin and the like.

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

When the optical information recording portion between the upper and lower substrates is completely partitioned by the hollow substrate or the sheet, the pressure and temperature of the two spaces change, and the difference between the pressure and the temperature in both spaces varies. Although it is considered that this may occur, such a thing is not preferable in terms of the mechanical characteristics of the optical information recording medium, and in order to make the gas atmosphere such as its temperature and pressure uniform, it is preferable to provide ventilation holes in the hollow substrate or sheet. preferable. The number of the holes is one or more, and the size is 0.1 to 5 m
m, and the shape is not limited to a circular shape, but may be any shape. Further, the position where the ventilation hole is provided is preferably outside the data area (usually near the inner periphery of the hollow substrate).

Next, a manufacturing process of the optical information recording medium of the present invention will be described with reference to FIGS. In this manufacturing process, each of the above members is used. A substrate 1 having a projection and a center hole 11 on the inner and outer circumferences on the side on which the recording layer is provided was manufactured by injection molding, injection molding, a mark transfer method, or the like. An information recording layer 4 was formed on each of the substrates 1. As the recording layer 4, for example, a cyanine-based recording layer,
Organic materials such as naphthoquinone and polymethylene, and T
Inorganic materials such as e, In, Se, and Te alloys may be used. For forming the recording layer 4, spin coating is mainly used in the case of an organic material, and evaporation, sputtering and the like are mainly used in the case of an inorganic material.

A pair of substrates 1 having a recording layer 4 are bonded to each other with the recording layer inside and the hollow substrate or sheet 5 sandwiched therebetween, and the hollow substrate protruding from the outer peripheral edge of the substrate 1. Or bend the part of 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 fitted to the outer peripheral end surface. Further, the bent portion 12 may be fixed by welding with heat, ultrasonic waves or a solvent, or by bonding with an adhesive.

As shown in FIG. 4, the fixing by the fitting frame member can be performed by a cylindrical or band-shaped frame member 6 having the same shape as the base material 1. However, in consideration of the adhesion and the like, an elastic metal material is used. It is preferable to use rubber, plastic, or the like. Furthermore,
As another mode of the fixing method using the fitting frame material, 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 material. May be pinched and fixed.

Incidentally, in order to allow the internal pressure and the external pressure of the information recording medium of the present invention to ventilate in response to a sudden pressure or temperature change in the external environment, the inside and outside of the substrate 1 and the hollow substrate or sheet 5 are interposed. At least one of the peripheral adhesive portions may be provided with an adhesive break portion 10 acting as a vent.
The width of the adhesive break may be about 0.3 to 5 mm. Such an adhesive break is particularly effective in a structure in which the substrate has convex portions on both the inner and outer peripheral portions thereof, and the hollow substrate or sheet is formed of a material having no vent hole.

[0012]

According to the present invention, it is possible to prevent an adverse effect on the recording / reproducing characteristics due to the reflected light from the recording layer on the opposite surface side, and to provide an optical information recording medium which can be further reduced in thickness and excellent in productivity. Become. Further, since the fill-shaped plate having the 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 the drawings]

FIG. 1 is a longitudinal sectional view of an optical information recording medium of an air sandwich structure in which spacers 2 and 3 are sandwiched between inner and outer peripheries which are conventionally known.

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

FIG. 3 shows a longitudinal sectional view of a hollow substrate integrated with a conventionally known spacer.

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

FIG. 5 is a longitudinal sectional view of the 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 an outer peripheral end surface of the substrate and a fitting frame material.

FIG. 6 is a longitudinal sectional view of the optical information recording medium of the present invention in which the end of the hollow substrate or sheet is bent and fixed to the outer peripheral end surface of the substrate by welding or bonding.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Inner peripheral spacer 3 Outer peripheral spacer 4 Recording layer 5 Hollow substrate or sheet 6 Fitting frame material 7 Fitting concave material 8 Vent hole of hollow substrate or sheet 9 Recording area 10 Adhesion break 11 Center hole 12 Bend

Continuation of the front page (72) Inventor Noboru Sasa 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-2-249151 (JP, A) JP-A-62-223836 (JP, A) JP-A-2-156436 (JP, A) JP-A-2-156437 (JP, A) JP-A-63-91829 (JP, U) JP-A-1-151426 (JP, U) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 7/24

Claims (5)

(57) [Claims] 1. An air sandwich having a pair of substrates having at least one substrate having an optical information recording layer therein, and a substrate or a film-like sheet between which the internal space layer is divided into two. In a structured type optical information recording medium, the pair of substrates have concentrically and continuously convex portions at least on the outer peripheral portion of the inner and outer peripheral portions, and the substrate or sheet is sandwiched by the convex portions. And an end portion of a substrate or a film-like sheet that divides an internal space layer between the substrates into two parts is fixed to at least one outer peripheral end surface of a pair of substrates by a frame material. Optical information recording medium. 2. 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 which divides an internal space layer into two between the pair of substrates. In a structured type optical information recording medium, the pair of substrates have concentrically and continuously convex portions at least on the outer peripheral portion of the inner and outer peripheral portions, and the substrate or sheet is sandwiched by the convex portions. And an end of a substrate or a film-like sheet that divides an inner space layer between the substrates into two is fixed by welding or bonding at least on one outer peripheral end surface of the pair of substrates. Optical information recording medium. 3. The optical information recording medium according to claim 1, wherein the projections provided on the pair of substrates are formed integrally with the substrates. 4. The light according to claim 1, wherein the substrate or the film-like sheet that divides the inner space layer between the pair of substrates into two has a transmittance for recording and reproducing light of 60% or less. Information recording medium. 5. A pair of substrates having convex portions on both inner and outer peripheral portions thereof, and bonding of inner and outer peripheral portions of a substrate or a film-like sheet which divides an internal space layer between the convex portions and the substrate into two. The optical information recording medium according to any one of claims 1 to 4, wherein at least one of the locations is provided with an adhesive break portion acting as a vent.