JPS6320743A - optical information recording medium - Google Patents

Abstract

PURPOSE:To obtain a recording medium having substantial sticking strength against shearing force by providing a projecting part to one substrate and a shoulder part to the other substrate over the entire circumference at the outside peripheral end of the recording medium and uniting the same by an adhesive agent. CONSTITUTION:Recording layers 3 consisting of Tb-Fe-Co films are formed on the plastic substrates 1, 2 and a central hole 4 is provided thereto. The projecting part 11 is provided to the circumference at the outside peripheral end of the one substrate 1 and the shoulder part 21 to the outside peripheral end of the other substrate 2 by masking and sputtering at the time of forming the recording layers 3. The disk is completed by using the adhesive agent 5 of a UV curing type and projecting UV rays to the adhesive agent to cure the same in order to stick and unit the substrates 1, 2. As a result, the projecting part 11 of the substrate 1 and the shoulder part 21 of the substrate 2 act together to counter the compressive force at the outside peripheral end when the shearing force is exerted to the recording medium. The recording medium with which the sticking strength and more particularly the substantial strength against the shearing force are assured is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a method that causes physical or chemical changes when irradiated with light to perform any or all of the processes such as recording, reproducing, and erasing information. The present invention relates to a disk-shaped optical information recording medium.

[Conventional technology]

In recent years, in the information recording field, in addition to conventional magnetic recording, optical recording, which records information by causing physical or chemical changes by irradiating it with light, has been researched and put into practical use as a non-volatile recording. It's coming. For example, for playback-only consumer use, home video discs, audio P
There are OM disks, etc.

The advantages of this optical recording over other recording methods, such as magnetic recording, are: (1) High-density recording is possible because the distance between recording tracks can be as close as 1 to 2 μm in radius.

◎ Easy maintenance and handling due to non-contact recording and playback.

01 Low cost per bit.

◎ Many types of recording media are disk-type, and access is much faster than other high-capacity recordings such as borosilicate tape.

In the industrial society that will require large amounts of information to be recorded in the future, this is definitely the preferred recording method, and it can be erased and
Rewritable optical recording is also at the research and practical stage.

However, in optical recording, the bits are minute and are easily affected by dust, scratches, etc. during use, so two transparent substrates with a recording layer on at least one side are used, with the recording layer facing inside. There are two types of structures, such as the so-called air sandwich type, which is bonded via a spacer or a convex portion provided on the substrate, and the so-called close bond type, where the entire surface is bonded directly with adhesive, with the recording layer facing inside. Optical information recording media have been proposed, and in these structures, the recording layer is not exposed to the outside, so it is possible to prevent the influence of dust, scratches, etc. on the recording layer. In optical information recording media with these two types of structures, the recording layer, etc. is protected with adhesive, etc., so it is highly reliable in terms of weather resistance, etc., and it is also thinner and bonded together. The structure of the shape is excellent.

On the other hand, it is difficult to ensure sufficient adhesive strength between an inorganic layer such as a recording layer and an adhesive without impairing the performance of the recording layer, etc., and as a result, optical information recording media lack strength. Therefore, a proposal was made to improve the strength of the optical information recording medium by ensuring the adhesive force between the adhesive and the substrate without forming the recording layer near the center hole or the outer peripheral edge of the substrate (for example, Japanese Patent Laid-Open No. 60-5439 (No. Publication).

[Problem that the invention seeks to solve]

However, the above-mentioned conventional technology has the following problems.

Mechanical throwing effect%7 as a factor governing adhesive strength
7ndeawarska, kushinka, intermolecular entanglement,
There are covalent bonds, etc., but in the above proposal, by securing an adhesion area between the adhesive and the substrate whose molecular structure is more similar than that of the recording layer, we expect effects such as 7 Ander Waalska and intermolecular entanglement to occur. However, increasing the area on the substrate in which no recording layer is formed sacrifices the recording capacity of the optical information recording medium, so it is not possible to increase the area on the non-recording layer very much. Therefore, it is difficult to ensure sufficient bonding strength.

The present invention is intended to solve these problems, and its purpose is to provide an optical information recording medium that easily secures sufficient bonding strength without sacrificing the recording capacity of the optical information recording medium. It is in a place where we provide.

[Means for solving problems]

The optical information recording medium of the present invention is capable of recording, reproducing, and erasing information, etc., by irradiating at least one disc-shaped substrate with light to cause a physical or chemical change. An optical information recording device comprising two substrates having a recording layer subjected to the process, and an adhesive is filled between the substrates without a gap so that the recording layer is sandwiched between the two substrates. In the medium, the two substrates include a first substrate having a protrusion on an outer peripheral edge, and a shoulder portion on the outer circumferential edge that is associated with the protrusion of the first substrate via the adhesive. ◇ [Example] FIG. FIG. 2 is a sectional view of an optical information recording medium (hereinafter abbreviated as disk in the embodiment) in one embodiment of the present invention, and FIG. 2 is an enlarged sectional view of portion A in FIG. 1. 1st
In the figure, 1 is a first substrate, 2 is a second substrate, both of which are made of plastic, and 4 is a central hole provided in a certain one of the first and second substrates. 3 is a recording layer formed on the substrates 1 and 2, and the recording layer 3iTb-Fe-Oo1t% is formed by sputtering to a thickness of about 1o o o (X). As shown in FIG. 2, the first substrate 1 has a protrusion 11 circumferentially provided at its outer peripheral end.
The amount of protrusion of this protrusion 11 from the substrate 1 is approximately 04-
), and the width of the protrusion 110 is about 15 (b). Further, the outer peripheral end of the second substrate 2 has a shoulder portion 21, as shown in FIG.
The amount of indentation from shoulder part 2 is about α6H this time, and shoulder part 2
The width of 1 is about 18 (b). Board 1 used this time
．． The external dimensions of 2 are the outer diameter 130-) and the diameter of the center hole 4 15-
b), since the thickness is approximately t2 (b), the proportion of the above-mentioned protrusion 11 and shoulder 21 in the entire substrate 1.2 is very small. Moreover, the substrates 1 and 2 in one embodiment of the present invention are manufactured by partially changing a conventional molding die.

In the present invention, the protruding portion 11 of the first substrate 1 and the shoulder portion 21 of the second substrate 2 are connected to the substrate 1,
In order to achieve the object of the invention by combining the adhesive 5 filled when bonding the two spacers together, the protrusion 11 and the shoulder 21 are masked and sputtered when forming the recording layer 6 described above. In this case, an ultraviolet curing adhesive 5 was used to bond the first substrate 1 and the second substrate 2 together, and the first substrate 1
A required amount of adhesive 5 is applied on top of the upper recording layer 5, and the second substrate 2 is placed on top of it so that the recording layers 3 are diagonal to each other.
The adhesive is filled between the substrates 1 and 2 by pressing the substrates 1.2 degrees apart while aligning the center holes 4 of each substrate so that they are aligned. Then, the adhesive 5 used this time is cured by irradiation with ultraviolet rays, and the disk is completed.

Further, the embodiments of the present invention are not limited to the above, and FIG. 3 shows an example of application of the present invention in the case where the recording layer 3 is formed only on one of two substrates. To protect the recording layer 3 from penetration etc., a protective layer 6 (Afi
FIG. 4 shows an example of the application of the present invention in which a layer (N formed by sputtering) is formed between the recording layer 3 and the substrate. In addition to the example shown in FIG. 4, adhesive 5 and recording layer 5 are added.
FIG. 5 is an application example in which a protective layer 6 is formed between the recording layer 3 and the adhesive 5, and furthermore, in order to eliminate the influence of moisture penetration from the substrate on which the recording layer 3 is not formed on the adhesive 5. In addition to the example shown in FIG. 5, FIG. 6 shows an application example in which the protective layer 6 is formed on a substrate on which the recording layer S is not formed, and the present invention also applies to these application examples as well. It has an effect. In addition, the recording layer 3 shown in FIGS. 4 and 5
It goes without saying that the present invention can be applied even when the configurations of the protective layer 6 and the protective layer 6 are symmetrical between the two substrates.

In addition, the plastics used for the substrate are made of a wide variety of materials, and some materials do not have good peelability from the mold during molding.
FIG. 7 shows an example of application of the present invention in which the protrusion 11 of the first substrate 1 is sloped in order to improve the separation of the substrate from the mold due to material trapping of the substrate. ,
An application example in which the shoulder portion 21 of the second substrate 2 is inclined is shown in FIG.
FIG. 9 shows an example of application in which both of them are inclined.

Incidentally, the present invention is concerned with ensuring bonding strength depending on the shape of the substrate, and the recording layer is made of Si.

We, f:'u, Mg, Zn, Or, Ni, Mn, Te
.

Ss, Sn, Ge, Co, Eng, Gd, Sm, Dy.

Metals composed of single or two or more compositions such as Nd, Y, V, Tb, and Ti, metal alloys such as Bi, As, and Sb, and organic substances such as polyvinyl butyral, nitrocellulose, and polyvinyl alcohol, etc. , and as a protective layer, Si, An, Zr.

Nitrides or oxides such as T i , B & , and Cja also have similar effects.

〔Effect of the invention〕

Until now, in closely bonded optical information recording media, flat substrates have been bonded together, so van der Walls forces and intermolecular entanglement are the only factors that can be relied upon to ensure adhesive strength. In particular, it has been difficult to manufacture an optical information recording medium that is susceptible to shearing forces applied within the plane of the substrate and has sufficient bonding strength.However, as described above, according to the present invention, the protrusion of the first substrate and the shoulder part of the second substrate are joined together with an adhesive, and the joined part is formed at the outer peripheral end of the optical information recording medium over almost the entire circumference.
Even if a shearing force is applied to the optical information recording medium, the adhesive in the union part resists the compressive force between the protrusion of the first substrate and the shoulder of the second substrate, especially at the outer peripheral edge where the shearing force is applied. Once cured, the adhesive has sufficient strength against compressive force, resulting in the effect of ensuring sufficient bonding strength for optical information recording media, especially sufficient strength against shear force. have In addition, the space between the protrusion and the shoulder becomes an adhesive reservoir, which also has the effect of preventing excess adhesive from flowing out to the outer edge.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an optical information recording medium in an embodiment of the present invention. Figure 2 is an enlarged sectional view of part A in Figure 1. Figures 3, 4, 5, 6, 7, 8, and 9 are other embodiments of the present invention. FIG. 1...First substrate 2...Second substrate 3...Recording layer 4...Center hole 5...Adhesive 6.・・・Protective layer 11 ・・・Protrusion 21 ・・・ Above the shoulder Applicant Seiko Epson Co., Ltd. Agent, Patent Attorney Tsutomu Mogami and 1 other person 5〆゛, 2... Virtue) Figure 3

Claims (1)

[Claims] A recording layer that performs any or all of the processes of recording, reproducing, and erasing information by causing physical or chemical changes by irradiating at least one disk-shaped substrate with a central hole with light. In an optical information recording medium, the optical information recording medium is provided with two substrates having at least two substrates, and an adhesive is filled between the two substrates without a gap so that the recording layer is sandwiched between the two substrates. The structure of the substrate includes a first substrate having a protruding portion on the outer peripheral edge, and a second substrate having a shoulder portion on the outer peripheral edge that is associated with the protruding portion of the first substrate via the adhesive. An optical information recording medium, characterized in that the recording layer is formed so as not to reach the center hole of the substrate and the combined portion of the first and second substrates.