JPS58130453A - Information storage medium - Google Patents

Abstract

PURPOSE:To absorb the change in the internal pressure in a space part formed between substrates, to prevent bend and undulation of the substrates and to maintain performance for a long time by providing a cavity part communicating the space part and a vent hole, and further providing a member for preventing intrusion of unnecessary materials. CONSTITUTION:The 2nd substrate 6 having higher rigidity is superposed and adhered on the surface side of a disc substrate 1 to be formed with an information forming layer in such a way that a space part 5 is formed between the same and the surface of an information forming layer 2 by way of an inner spacer 3 and an outer spacer. A protecting case 8 has a depressed part in which the substrates 6 side opens, and a cavity part 9 is formed on the outside surface side of the substrate 6. An annular expansion film 13 as a member for preventing intrusion of unnecessary materials is provided in the part 9 of the case 8. When the internal pressure P1 in the part 5 rises higher than external pressure P2, the film 13 deforms so as to project to the cavity 9e side, and in the opposite case, said film deforms so as to project to the cavity 9a side.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an information recording medium that can be applied, for example, as an optical disc or a video disc.

[Technical background of the invention and its problems]

In recent years, optical disk memories have become capable of high-density recording, non-contact recording and playback, high-speed random access, excellent long-term storage, easy recording methods, additional recording, and low per-bit performance. Due to its low cost and other features, it is widely used for recording/playback or for playback only. Applications for playback-only types include home video discs, professional video discs, and audio-P.
There are CM f disks, etc., and recording/playback type applications include document files, BIIO files, and general-purpose memory for a total of one machine.

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

However, since it is necessary to irradiate the information forming layer 1 with Radhe light through the substrate, the substrate cannot be made very thick, and the elasticity of the plastic substrate itself is not very strong, so it is difficult to make the substrate sealed in a space. There are problems such as bending or waviness due to changes in the external environment such as expansion or contraction due to temperature changes in air or gas, 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, resulting in 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 impossible. There are serious problems.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its purpose is to prevent bending and waviness of the board as much as possible while having a simple configuration, and to enable stable information processing over a long period of time. The aim is to provide a highly reliable information storage medium with high reliability.

[Summary of the invention]

In the present invention, a cavity is provided on the outer surface of one of the substrates and communicates with the space formed between the substrates through a ventilation hole, so that changes in the internal pressure of the space can be absorbed. It is something.

[Embodiments of the invention]

The present invention will be explained below with reference to an embodiment shown in FIGS. 1 to 3. 1 in the figure is, for example, an outer diameter of approximately 300 mm,
The first substrate is made of a plastic plate with an inner diameter of about 35 mm and a thickness of about 1 to 2 mm. On one side of the first substrate 1, an information forming layer 2 consisting of a recording layer or a light reflecting I- is formed in the form of a chip by vapor depositing a metal such as Te.

A space 5 is formed on the information forming layer formation side of the first substrate 1 between it and at least the surface of the information forming layer 2 via an inner spacer 3 and an outer spacer 4 arranged concentrically. The second substrate 6 is polymerized and bonded so as to be bonded.

This second substrate 6 has the same inner and outer diameters as the first substrate 1, but has greater rigidity than the first substrate 1.
This serves as a reinforcing plate to prevent the board 1 from bending or waviness. The second substrate 6 as a reinforcing plate is made of a metal plate or a plastic plate.The thicker the plate, the more sufficient strength can be obtained against external forces.
In the case of plastics, it is good to have about 1.5 to 5 fields.

Further, an annular protective case 8 is attached to the outer surface of the second substrate 6 at a position corresponding to the inner spacer 3 and covers a member 7 for preventing unwanted substance intrusion 5 to be described later. This protective case 8 has a concave portion that is open on the second substrate 6 side, so that a cavity 9 is formed on the outer surface side of the second substrate 6.

Further, the empty space 9 formed in the protective case 8 is located in the second
The reed is in communication with the space 5 formed between the substrates 1 and 6 through the ventilation hole 1o formed in the substrate 6, so that when the internal pressure of the space 5 changes, it can be absorbed. It has become.

In order to prevent the protective case 8 from becoming larger than the outer diameter of the inner spacer 3, a notch 1 is provided at the outer peripheral edge of the inner spacer 3.
1 is provided, and the ventilation hole 10 and the space 5 are communicated through the notch 11. In addition, upper air vent 1
Of the adhesive flow prevention grooves 12 formed annularly on the surface of the inner groove 3, o is bored opposite to the groove 12 that intersects with the notch. Vent hole 1
6- is formed so that the space 5 and the ventilation hole 10 can be communicated through the gap between the grooves 12 even if they are bonded in a state where the 0 is deviated.

Further, a hollow space 9 formed in the seed collection case 8 is provided with an annular stretchable membrane 13 as a member 7 for preventing intrusion of unwanted substances, and is a first space communicating with the space 5 through the ventilation hole 10. It is divided into a chamber 9a and a second chamber 9b which communicates with the atmosphere through a through hole 14 formed in the protective case 8. The stretchable membrane 13 is made of synthetic rubber or the like with a thickness of about 0.1 tone.

In the information storage medium configured as described above, the rigidity of the second substrate 6 serving as a reinforcing plate provides sufficient strength against external forces to the first substrate 1 on which the information forming layer 2 is formed. It is possible to prevent the first substrate 1 from bending or undulating.

In addition, when a temperature change or a pressure difference occurs between the outside air and the outside air, that is, when the internal pressure P1 of the space 5 becomes larger than the outside pressure P2, the second
conversely, when the internal pressure P1 becomes smaller than the external pressure P2, it deforms so as to protrude toward the first cavity 9a, Above internal pressure P
The volume can be changed to a state where there is almost no pressure difference between L and the outside pressure P2.

Therefore, even if a temperature change or a pressure difference occurs between the first substrate 1 and the outside air, bending or waviness of the first substrate 1 can be prevented.

In addition, the stretchable film 13 prevents unnecessary substances such as external dust υ and moisture from entering the space 5 through the empty space 9, and also prevents the space from entering into the space 5. Even if the part 5 is filled with nitrogen gas or inert gas, this will not leak to the outside.

Further, the stretchable film 13 is housed in the protective case 8, and can prevent artificial damage when handling multiple media.

Note that the present invention is not limited to the above-mentioned embodiment, but may be modified as shown in FIG. 4. That is, the second substrate 1 may be not just a reinforcing plate, but may also be a transparent substrate having an information forming layer 2, and an information storage medium on which information processing can be performed on both sides. Further, although the stretchable membrane 13 is used as a member for preventing the intrusion of unnecessary substances, a filter 15 may also be used.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the gist of the present invention.

In the description of the other embodiment (FIG. 4), the same parts as those of the previous embodiment are given the same reference numerals and the explanation thereof will be omitted.

〔Effect of the invention〕

As explained above, the present invention provides a cavity on the outer surface side of one of the substrates that communicates with the space formed between the substrates via the ventilation hole, and when the internal pressure of the space changes. This has the effect of providing a highly reliable information storage medium that prevents bending and waviness of the substrate as much as possible despite its simple structure and allows stable information processing over a long period of time. play. Furthermore, the protective case covers the unnecessary material intrusion prevention member that prevents unnecessary materials from entering the space through the empty chamber, thereby preventing human damage when handling multiple media, etc. It has the effect of making it possible.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention,
Fig. 1 is a partially cutaway schematic plan view, Fig. 2 is a schematic longitudinal sectional view of 11111, Fig. 3 is an enlarged view of main parts, and Fig. 4 is a schematic diagram showing another embodiment of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... First substrate, 2... Information forming layer consisting of a recording layer or a light reflection layer, 3... Inner spacer, 4...
Outer spacer, 5... Space portion, 6... Second substrate (
Reinforcement plate), 7... Unwanted substance intrusion prevention member, 8... Protective case, 9... Vacant space, 10... Ventilation hole, 13.
...Stretchable membrane, 15...filter. Applicant's agent Patent attorney Takehiko Suzue -10-

Claims (2)

[Claims] (1) It has an information forming layer consisting of a recording layer or a light reflecting layer, and at least the information formed in the information forming layer can be read by irradiating the information forming layer with a laser beam or the like. In the information storage medium, the information forming layer is formed on one side of the first substrate, and the information forming layer is formed on the information forming layer side of the first substrate, and at least the information forming layer surface is connected to the information forming layer forming side of the first substrate through a spacer. A second substrate that is polymerized and integrated so that a space is formed therebetween, and a second substrate that communicates with the space through an outer surface of the second substrate and a ventilation hole formed in the substrate. A cavity part for absorbing changes in the internal pressure of the above-mentioned space formed, and an annular waste substance intrusion prevention part for preventing unnecessary substances from entering the space part 1 through this cavity part. An information storage medium comprising: a member; and a protective case attached to a substrate so as to cover the member for preventing intrusion of unnecessary substances. (2) The information storage medium according to claim 1, characterized in that the protective case has a cavity formed in the protective case to compensate for changes in the internal pressure of the space formed between the substrates. .