JPS59186150A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To improve the parallelism and workability of a substrate by interposing plural spherical bodies having an identical radius between an inner circumferential region and an outer circumferential region of two discoid substrates having a hole at the center and bonding the bodies by means of an adhesives. CONSTITUTION:The plural spherical bodies (e.g., glass balls) 13-16 having identical radiuses are arranged to the inner circumferential region and the outer circumferential region of the two circular transparent substrates 1, 2 having holes 3, 4 at the center together with adhesives 17-20 to bond the substrates 1 and 2. Since the spherical bodies 13-16 are arranged scatteringly, the parallelism and workability of the substrates 1, 2 are improved.

Description

[Detailed description of the invention] The present invention relates to improvements in optical information recording media.

Conventionally, this optical information recording medium has two disc-shaped transparent substrates 1.2 with holes 3 and 4 formed in the center, as shown in FIGS. 1(a) and (1)). It is constructed by forming information recording layers 5 and 6 on a circumferential area, and by irradiating a laser beam from the transparent substrate 1.2 side, a hole of about 1 μm is formed in the information recording layer 5.6, and the hole is formed. Information is reproduced by changing the reflectance depending on the presence or absence of the light.

This optical information recording medium has an information recording layer 5.6.
In order to prevent deterioration due to outside air, especially humidity,
An inner circumferential plate 7 and an outer circumferential plate 8 are inserted as spacer materials into the inner circumferential area and outer circumferential area of the disc-shaped transparent substrates 1 and 2, and the upper and lower surfaces of these and the two circular The two disk-shaped transparent substrates 1.2 are bonded with adhesive 9.10.11.12 interposed between the plate-shaped transparent substrate 1.2 and the information recording layer 5.6 is shielded from the outside air. The structure is such that

However, in conventional optical information recording media, adhesive 9
Since it is difficult to make the thickness of ~12 uniform,
The parallelism of the transparent substrates 1 and 2 may be forced to decrease, or the thickness of the inner circumferential plate 7 and outer circumferential plate 8 as spacer materials may be reduced to 0.
When the comb is thin to 5 mm or less, it becomes difficult to handle and the workability is reduced.

The present invention has been made to eliminate the above-mentioned drawbacks, and includes a plurality of spherical bodies having substantially equal diameters scattered on an inner circumferential region and an outer circumferential region, and two spherical bodies having substantially equal diameters. An object of the present invention is to provide an optical information recording medium in which the parallelism and workability of the transparent substrate are improved by bonding the transparent substrate in contact with the disk-shaped transparent substrate through the use of an adhesive.

FIGS. 2(a) and 2(b) show a cross-sectional view and an enlarged partial cross-sectional view of an embodiment of the optical information recording medium according to the present invention.

The appearance is the same as that shown in FIG. 1(a), and the same functional parts as those shown in FIG. 1 are denoted by the same reference numerals.

The transparent substrate 1.2 in this example has a diameter of 300 mm and a thickness of 1.2
It is a disk made of soda lime glass with a diameter of 3.5 mm in the center. /I is open.

In the intermediate circumferential region of the transparent substrate 1.2, information recording layers 5 and 6 made of a tellurium film (film thickness 200 to 300 layers) are formed, and two information recording layers 5 and 6 are arranged facing each other. Two transparent substrates 1 and 2 are arranged with their centers aligned.

Next, a plurality of spherical bodies 13, 14, 1, which is a feature of the present invention,
5.16 is a glass bulb with a diameter of 100 μm, and epoxy adhesive 17.18 is applied on the inner circumferential area and the outer circumferential area located on both sides of the intermediate circumferential area of the transparent male plates 1 and 2. ,1
9.20 are interposed and scattered. In the case of a cross section when looking at the outer circumference from the hole 3.4, this dotted state is shown in the drawing as four pieces uniformly arranged in each of the inner circumferential area and the outer circumferential area for the sake of explanation. The width of each region is 2 mm in this example, and the diameter of the spherical bodies 13 to 1G (10
Since the diameter is 20 times that of 0 μm), in reality, several to several pieces are unevenly scattered in one cross section. Therefore, when two transparent substrates 1゜2 are pressed together and joined together, the interval t is the diameter of the spherical bodies 13 to 16 (for example, +2 to the diameter dimension).
Even if there is an error of 0%, the upper limit of the diameter dimension (+20
%) diameter in the vicinity) of the transparent substrate 1
, 2 can be improved in parallelism.

Next, regarding the workability when bonding the two transparent substrates 1 and 2, a plurality of spherical bodies 13 to 16 are placed on the inner circumferential area and on the outer circumferential area as described above together with the adhesives 17 to 20. Even if the diameter of the spherical bodies 13 to 16 becomes small, this can be done extremely easily compared to conventional thin plate-shaped spacer materials.

Furthermore, regarding the adhesive strength of the adhesives 17 to 20, since an extremely thin adhesive layer of 0 to several μm is formed near the contact between the transparent substrates 1 and 2 and the spherical bodies 13 to 16, The volume change associated with curing of the agent is reduced,
The number of adhesive layers is reduced, and the adhesive strength can be significantly improved compared to conventional planar adhesive layers.

The present invention is not limited to the materials listed in the above embodiments; the transparent substrate material may be plastic, and the spherical body material may be plastic or metal. The adhesive may be a viscous adhesive such as epoxy, but in order to easily prevent leakage to the information recording layers 5 and 6, it is preferable to use an adhesive (e.g. room temperature curing). Two-component engineered poxy adhesive T-
530 (Amicon Co., Ltd. product), flexible type U
V-curing resin CV 7005 (Matsushita Electric Works Co., Ltd. product)
is used.

[Brief explanation of drawings]

Figure 1 shows a conventional optical information recording medium;
) is a perspective view showing its appearance, and the same figure (b) is the same figure (
It is a sectional view of x-xm point of a). FIG. 2 shows an optical information recording medium according to the present invention, and FIG. 2(a) is a cross-sectional view similar to FIG. 1(b), and FIG.
) is a partially enlarged view. 1.2... Disc-shaped transparent substrate, 3, 4... Hole, 5.6
...Information recording layer, 13,14,15.16...Spheroidal body, 17.18,19.20...Adhesive 6-

Claims (1)

[Claims] (1) An information recording layer is formed on the middle circumferential area of two disc-shaped transparent substrates with a hole formed in the center, and the information recording layer faces the two disc-shaped transparent substrates. placed in the direction of
The two disk-shaped transparent substrates are bonded together with an adhesive interposed on an inner circumferential area and an outer circumferential area located on both sides of the intermediate circumferential area of the disk-shaped transparent substrate. In the optical information recording medium, a plurality of spherical bodies having substantially equal diameters are provided on the inner circumferential region and on the outer circumferential region! are scattered over the fi area,
An optical information recording medium, characterized in that it is in contact with the two disc-shaped transparent substrates.