JPS61120358A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To eliminate the double refraction of a cover disk and to hold gap length constant over the entire surface by using the cover disk manufactured by a self-casting system, and the holding the gap between it and a disk plate by gap holding parts provided to a thin plate of mesh structure and an outer peripheral sealing member. CONSTITUTION:The cover disk 1 is formed of a transparent plastic material such as acrylic resin by the self-casting system to obtain a discoid shape having constant thickness, and this has much smaller double refraction and less residual internal stress than that manufactured by an injection system, so the shape of a flat plate is maintained correctly. A spacer 14 has an external diameter D a little bit smaller than the internal diameter of the information recording area of the disk plate 1 and an internal diameter (d) a little bit larger than the diameter of the center hole 1a of the disk plate 1 and is formed in the mesh structure by weaving thin thread. The outer peripheral sealing member 15 has two gap holding parts 15a projecting from its inner periphery and their gap is equal to the thickness of the disk plate 1, which is equal to the thickness of the spacer 14. The outer periphery 13a of the cover disk 13 is adhered to the inner periphery of the outer peripheral sealing member 15 with an adhesive to assemble the medium.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical information recording medium, and in particular, a medium for recording information with high density using a light source with high energy such as a laser beam. , and readout of recorded information is O
The present invention relates to an optical information recording medium that can be used for a long time.

[Conventional technology]

Conventional optical information recording media are configured to convolute or reproduce information by projecting recording or reading light from the surface of the medium, so information can be stored on one or both sides of the disk. forming a thin film for recording;
Both the top and bottom of the disk plate to protect the I membrane? ! 11t-
A so-called sandwich structure is formed between the cover disks, and by sealing the outer periphery of the disk plate and the vicinity of the upper and lower surfaces of the center hole, the sealed structure is protected from the external environment such as dust, moisture, and gas. As a means for this purpose, conventional optical information recording media are
As shown in FIG. 3, protruding portions 3a and 3be are integrally formed on the inner and outer circumferential portions of the inner surface of the cover disk 3 itself, and a joint portion 3c is provided on the outside of the protruding portion 3b. Sandwich the disk plate l between the cover disks of
Between the protruding parts 3c and between the protruding parts 3a and the disk plate l
A sealed structure is formed by bonding the surface of the holder with an adhesive. At this time, the distance between the cover disk 3 and the disk plate 1 needs to be precisely maintained at a constant dimension to keep the optical path length of the light constant for continuous or continuous use.
In addition to making the thickness of the protruding portions 3a and 3b equal to the required gap distance between the cover disk 3 and the thin film 2 for information recording provided on the surface of the disk plate 10, a predetermined gap length is specially set. It is structured like this.

[The problem that the invention attempts to solve]

However, in the conventional means as described above, (a) the cover disk 3 is manufactured using an injection mold method in which material is injected under high pressure; There is birefringence, which deteriorates the optical characteristics when storing and reading information; (b) There are variations in the dimensions of the protruding parts 3a and 3b, and there are variations in the thickness of the adhesive for bonding. (c) The above-mentioned internal stress and protruding portion 3a
Since the cover disk 3 is deformed due to the adhesion of the disk plates 1 and 3b, there are drawbacks such as the fact that the gap length is not constant over the entire surface of the disk plate 1.

Therefore, it is an object of the present invention to provide an optical recording medium with excellent optical characteristics, in which the cover disk has no birefringence and the gap length between the cover disk and the disk plate can be kept constant over the entire surface. It is in.

[Means for solving inter-group points]

The optical information recording medium of the present invention includes a disk plate having a thin film for recording information on one or both sides, and two transparent cover disks held and arranged at a predetermined interval outside the disk plate. In the optical information recording medium provided, the inner peripheral sides of the disk plate and the cover disk have a thickness equal to the predetermined interval, and form a mesh structure with thin wires, so that the inner diameter of the information recording area of the disk plate is Glue and seal through a spacer with a small diameter outer tl.
The outer circumferential sides of the disk plate and the cover disk are provided with two gaps that protrude inward and have a size equal to the predetermined spacing, and whose spacing is 1−+ equal to the thickness of the disk plate. The outer periphery of the outer periphery of an outer periphery sealing member having a holding portion and the outer periphery of the cover disk are bonded and sealed, and the disk plate is supported between the two gap holding portions.

In other words, the optical information recording medium of the present invention uses the so-called cell casting method (casting method) in which material is injected and molded without applying pressure, in order to solve the drawbacks of the optical information recording media of OQI and America. Using the manufactured flat plate-shaped cover disk, the gap between this and the disk plate can be maintained at a constant dimension with high precision using a thin plate with a mesh structure (Mesches Bener→) and a gap holding part provided on the outer sealing member. It is something.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, the present invention will be described in detail with reference to drawings showing embodiments.

FIG. 1 is a sectional view showing an embodiment of the present invention.

In the figure, reference numeral l is a record carrying member for optically recording information, and a thin film 2 for information recording is provided on both or one side of the member (different from the conventional one shown in Fig. 3). Same output). Cover disks 13 are arranged on both the upper and lower surfaces of the disk plate 1, and in order to keep the distance (gap) between the disk plate l and the cover disk 13 constant, a spacer 14 is provided at the inner circumference between them. However, a gap holding portion 15a protruding inward from the outer circumference sealing member 15 is interposed in the outer circumference (spacer 1 of the disk plate 1).
4 and the gap holding portion 15a is the information recording area).

The cover disk l is made of transparent plastic material such as acrylic resin using the cast-in-cell method and has a rectangular plate-like shape with a certain thickness. Compared to the conventional method, birefringence is extremely low, and the residual internal stress is also small. As shown in FIG. 2, the spacer 14 has an outer diameter slightly smaller than the inner diameter of the information dd recording area of the disk plate l, and a center hole la of the disk plate 1.
It is a thin plate (mesh spacer) having a slightly larger inner diameter d and tl (as shown in Fig. 1) and having a mesh structure woven from fine wires. As the wire, a rust-resistant metal material such as stainless steel or brass, or glass fiber, or plastic fiber such as nylon, whose diameter is about half the thickness of the spacer, is suitable. The thickness of the spacer is equal to the required gap size between the cover disk and the disk plate.

In addition, the opening area (the part without wires in the mesh structure)
Experiments have shown that a ratio of opening (total area) of around 401 has yielded good results.

The disk plate 1, spacer 14, and cover disk 13 are bonded with adhesive and sealed from the outside. At this time, the adhesive bonds the disk plate and cover disk at the opening of the mesh spacer, so the distance between them is can be held precisely to a size equal to the thickness of the mesh spacer.

The outer periphery sealing member 15 seals the outer periphery 13a of the cover disk 13.
This is a sealing member for sealing the disc plate 1 by adhering its inner peripheral portion to the disc plate 1, and is conveniently divided into two parts for assembly.

The outer periphery sealing member 15 also has two gap holding parts 15a protruding from the inner periphery, the gap between them is equal to the thickness of the disk plate 1, and the thickness thereof is equal to the thickness of the spacer 14. It has become. Therefore, the disk plate 1 is placed between the gap holding parts, and the cover disk 13 is placed in close contact with the inside and outside of the disk plate 1, and the cover disk 13A is adhered to the inner circumference of the outer sealing member 15 with an adhesive. Assemble. Therefore, since no adhesive is used in the gap holding portion 15a, the distance between the disk plate 1 and the cover disk 3 can be maintained at an accurate predetermined dimension.

With the above configuration, the distance between the cover disk 13 and the disk plate 1 is maintained by the spacer 14 on the inner circumference side and by the gap holding part 1 of the outer sealing member 15 on the outer circumference side.
5m, and since the cover disk 13 is manufactured using a manufacturing method that does not have residual internal stress, there is no deformation due to metres, and the entire information recording area of the disk plate 1 (Z) is correctly maintained at a specified size. Dimensions can be maintained. When the disk plate 1 and the cover disk 13 are bonded together, since the mesh spacer described above is used, the adhesive is only supplied from one side of the mesh spacer, and the adhesive is supplied by light.

〔Effect of the invention〕

As explained above, by using the optical information recording medium according to the present invention, birefringence is extremely small and the distance between the disk plate and the cover disk can be maintained at a constant dimension with high precision, so that optical This has the effect that an optical information recording medium with excellent characteristics can be obtained.

It also has the advantage that workability in bonding work can be improved and the price of the optical information recording medium can be reduced.

[Brief explanation of drawings]

FIG. 41 is a sectional view showing an embodiment of the optical information recording medium of the present invention, FIG. 2 is a plan view showing details of the spacer in FIG. 1, and FIG. 3 is a sectional view showing a conventional optical information recording medium. It is a diagram. 1...Disc medium, 2...Thin film, 1
3...Kahatis/, 14...Spe? -, 15...Outer sealing member. $ / Sen 2nd $ 3 Figure

Claims (1)

[Claims] An optical information recording medium comprising a disk medium having a thin film for recording information on one or both sides, and a transparent cover disk disposed at a predetermined distance from the surface of the disk medium, the disk medium and the cover disk. The inner circumferential side of the disk medium is adhesively sealed via a spacer having a thickness equal to the predetermined spacing, formed with a mesh of thin wires, and having an outer diameter smaller than the inner diameter of the information recording area of the disk medium. , an outer periphery seal having a gap retaining portion on the outer periphery of the disk medium and the cover disk that protrudes inward and has a thickness equal to the predetermined interval and whose interval is equal to the thickness of the disk medium; An optical information recording medium characterized in that an outer portion of the inner circumference of the member and an outer circumference of the cover disk are adhered and sealed, and the disk medium is supported between the gap holding parts.