JPH0418084Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention is applicable to information storage media such as optical discs and video discs, and particularly relates to optical discs.

(Technical background of the invention and its problems) In recent years, optical disk memory has been developed to allow high-density recording, non-contact recording and playback, high-speed random access, excellent long-term storage, and new recording methods. It is widely used for recording, reproduction, or reproduction only because it has advantages such as easy recording, additional recording is possible, and low cost per pit. Applications for playback-only types include home video discs, commercial video discs, and audio discs.
There are PCM disks, etc., and recording and playback type applications include document files, video files, computer general-purpose memory, etc.

Conventionally, as one of the information storage media used in this type of information processing device, two plastic substrates each having a recording layer or a light reflecting layer formed on one side are used, and the information forming layers are located inside each other, and each There is an air sandwich type in which information forming layers are bonded together such that a space is formed between mutually opposing surfaces.

However, since it is necessary to irradiate the information formation layer with laser light through the substrate, the substrate cannot be made very thick, and the elasticity of the plastic substrate itself is not very strong, so Alternatively, there are problems such as bending or waviness due to changes in external phenomena such as expansion or contraction due to changes in gas temperature, or pressure differences with the outside air. If this bend or waviness is large, it will not be possible to correct the focal shift in the information processing device, leading to a decline in information processing accuracy, and in extreme cases, the information storage medium and the optical head may come into contact, making information processing itself impossible. Then there is a serious problem.

(Purpose of the invention) The present invention was developed based on the above-mentioned background circumstances, and its purpose is to prevent bending and waviness of the board as much as possible while providing a simple structure, and to provide stable information over a long period of time. The present invention provides a highly reliable information storage medium that can perform processing.

(Structure of the invention) The present invention is an air sandwich type in which two of the recording layers are bonded together with an adhesive so as to face each other via an inner circumferential spacer and an outer circumferential spacer to a recording medium having a recording layer on a substrate. An optical disc characterized in that the inner circumferential spacer and/or the outer circumferential spacer have at least one surface on which no adhesive is applied at a portion in the circumferential direction.

That is, the present invention provides one or more locations along the circumferential direction of the inner spacer and/or outer spacer where adhesive is not applied on one and/or both sides of the circumferential spacer and/or the outer spacer. The space between the spacer and the substrate becomes a ventilation hole between the space of the optical disk having the air sandwich structure and the outside air, so that when the internal pressure of the space changes, this change is absorbed. .

(Embodiments of the Invention) The present invention will be specifically described below with reference to the conventional examples shown in FIGS. 1 and 2.

1 in Figure 1 is, for example, an outer diameter of 130 m/m and an inner diameter of 15
This is a substrate made of a plastic plate with a thickness of 12 m/m and an information forming layer 2 consisting of a recording layer or a light reflecting layer on one side of which a metal such as Te (tellurium) is deposited. It is formed into a ring shape.

An air sand trench space 5 is formed between the surface of the information forming layer 2 of the substrate 1 and the surface of the information forming layer 2 via an inner spacer 3 and an outer spacer 4 arranged concentrically. The substrates 6 are overlapped and bonded by an adhesive layer 7 so that the substrates 6 are bonded together. The adhesive layers 7 and 7' are coated with adhesive on both sides of the inner circumferential spacer 3 and the outer circumferential spacer 4, respectively, along the circumferences of the spacers, and connect the air sand arch space 5 with the outside air. Ventilation holes 8, 8' (shown in Figures 3 and 4 of the present invention)
is not provided.

A specific example of the present invention is shown in FIGS. 3 and 4, in which the adhesive layers 7, 7'
Alternatively, the adhesive is not applied along the circumferential direction of the outer circumferential spacer 4, and the ventilation holes 8, 8' are provided as air gaps. There is no pressure difference between the disk and the outside air, so that distortion of the optical disk does not occur.

In addition, in order to prevent dust particles in the atmosphere from entering the air sand bench space 5, the thickness of the adhesive layers 7, 7' of the inner circumferential spacer 3 and/or the outer circumferential spacer 4 is set to the thickness of the adhesive layer 7, 7' of the inner circumferential spacer 3 and/or the outer circumferential spacer 4. It is preferable to adjust the thickness to around 5μ, which corresponds to a thickness of 8'.

(Effect of the invention) The optical disk of the invention has an inner spacer and/or
Or, place the area where adhesive is not applied on one side and/or both sides of the outer circumferential spacer along the circumferential direction of the inner circumferential spacer and/or outer circumferential spacer.
By providing an air gap of more than 100 mm, the air gap between the spacer and the board becomes a ventilation hole between the disk space of the air sandwich structure and the outside air, and absorbs any changes in the internal pressure of the space. By doing so, it is possible to prevent distortion of information recording media such as optical disks, and the maintenance and transportation work of optical disk products is simple.In addition, the appearance of optical disks is extremely good. It is also advantageous in terms of manufacturing costs in terms of alignment work.

[Brief explanation of drawings]

FIG. 1 shows a schematic vertical cross-sectional view of a conventional optical disk bonded together. FIG. 2 shows a partially cutaway plan view of a conventional optical disc bonded together. FIG. 3 shows a schematic vertical cross-sectional view of the optical discs of the present invention bonded together,
FIG. 4 shows a partially cutaway plan view of the optical discs of the present invention bonded together. Explanation of symbols, 1, 6...Substrate, 2...Information formation layer, 3...Inner spacer, 4...Outer spacer, 5...Air sand arch space, 7, 7'
...adhesive layer, 8,8'...ventilation hole.

Claims (1)

[Scope of utility model registration request] An air sandwich type optical disk comprising a recording medium having a recording layer on a substrate, the two recording layers being bonded together with an adhesive so as to face each other via an inner circumferential spacer and an outer circumferential spacer,
An optical disk characterized in that the inner circumferential spacer and/or the outer circumferential spacer have at least one surface on which no adhesive is applied at a portion in the circumferential direction.