JPS6331041A - Optical recording medium - Google Patents

Abstract

PURPOSE:To decrease the loss of time by positioning and to decrease offcentering as well by forming recesses and projecting parts for positioning to reciprocal positions of either one or both of the inside and outside peripheral parts of two sheets of disk substrates to be stuck to each other. CONSTITUTION:The disk substrate 1 is manufactured of a transparent thermoplastic resin by injection molding and has the recesses 1a, 1b in the inside and outside peripheral parts. A recording layer 3 is formed by sputtering on the substrate. The recording layer 3 is a magneto-optical recording medium consisting of; for example, Tb-Fe-Co, etc. The transparent disk substrate 2 consisting of the similar material is manfactured by injection molding so as to face the substrate 1. Said substrate has the projecting parts 2a, 2b reciprocally opposed to the recesses of the substrate 1 in the inside and outside peripheral parts. The disk substrate 1 and 2 are stuck to each other by an adhesive agent 4. As a result, the disk substrates 1 and 2 are adhered with the recesses 1a, 1b and the projecting parts 2a, 2b as guides; therefore, the optical recording medium with which the offcentering is decreased is efficiently produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical recording medium having a structure in which two disk substrates are bonded together.

[Summary of the invention]

The present invention applies to laser discs, DRAW discs, E-
In an optical recording medium with a bonded structure such as a DRAW disk, the convex portions and four portions are placed relative to each other on one or both of the inner and outer circumferential portions for alignment of the bonding on two disk substrates. By providing a difference of 0.2 rtm or more between the center hole diameters of the two disk substrates, the efficiency of the bonding process can be increased, and the eccentricity of the recording group diameter with respect to the center of the disk during bonding can be improved. This prevents

[Conventional technology]

To manufacture photocatalysts with a laminated structure such as laser discs, DRAW discs, and DRAW discs, first, a transparent thermoplastic resin such as acrylic resin or Zarycarbonate resin is injection molded to form pits or holes on the surface. , create a disk board with groups. On this side,
Optical recording media film 9 After the reflective film and the like are formed by sputtering or vacuum evaporation, they are bonded together using an adhesive such as an ultraviolet curing resin. This is done using the outer diameter as a guide.

[Problem that the invention seeks to solve]

However, in the conventional technology, since the center hole or the outer diameter is used as a guide, the alignment of the two disk substrates is insufficient, and the eccentricity of the pits or groups in the recording area with respect to the center of the disk tends to increase. there were. Furthermore, when two discs have the same center hole diameter and misalignment occurs between the two discs, this tendency becomes even more pronounced, causing tracking errors and affecting the yield in the production of optical recording media.

The invention is intended to solve these problems, and aims to improve yield by preventing eccentricity and improve productivity by simplifying alignment of two disks.

[Means for solving problems]

In order to solve the above-mentioned problems, the recording medium of the present invention has a method for positioning the entire or part of either the inner peripheral part or the outer part of two disk substrates that are bonded together, or both. The convex portion and the concave portion should be provided at opposite positions, and the center hole diameter of the two disk substrates should be cL2w.
It is characterized by having a difference of n or more.

[Effect]

According to the invention, there are convex portions on two disk substrates.

By providing the concave portions at opposite positions, alignment during bonding can be easily performed, productivity is improved, and eccentricity due to positional deviation is almost eliminated, thereby improving quality.

Furthermore, by creating a difference in the center hole diameter of the two disk boards, eccentricity caused by misalignment of both center holes is eliminated, and the center hole of one disk is always used as a reference when setting it in the drive. It is now possible to solve problems such as tracking errors caused by changing the direction of the set.

〔Example〕

FIG. 1 is a sectional view for explaining the structure and manufacturing process of an optical recording medium according to an embodiment of the present invention.

In the figure, a disk substrate 1 is made of thermoplastic transparent resin such as polycarbonate by injection molding, and has four parts 1α and 1h2 on its inner and outer peripheries. A recording layer 3 is formed on this substrate by sputtering.

The recording N3 is, for example, a magneto-optical recording medium such as T b -F e -Oo.

Opposed to this substrate 1, a transparent disk substrate 2 made of the same material is manufactured by injection molding.

It has convex portions 2α and 2b facing the four parts of the substrate 1 on its inner and outer circumferential portions. The disk substrates 1 and 2 are bonded together using an adhesive 4.

As the adhesive, a photosensitive resin is used for bonding in a short time. For example, UVX (manufactured by Three Pond), A
A vinyl ester liquid photosensitive resin that does not contain a solvent, such as -705 (manufactured by Block Chemical Co., Ltd.), is applied with a spinner to the surface of the substrate 10, and after vacuum degassing, the convex portions of the substrate 2 are adjusted to fit the concave portions of the substrate 1. The material was bonded to the substrate and cured and bonded by irradiation with ultraviolet light.

As a result, disk substrates 1 and 2 have four parts (1α, ib)
Since the convex portions (2α, 2b) are used as guides for adhesion, it has become possible to efficiently produce optical recording media with less eccentricity.

〔Effect of the invention〕

As explained above, the present invention is capable of producing light by forming recesses and protrusions for positioning at opposing positions on one or both of the inner peripheral part and outer part of two disk substrates to be bonded together. This has the effect of reducing time loss due to alignment of two disks when assembling a recording medium, and also reducing eccentricity.

Furthermore, by changing the sizes of the center hole diameters of the two disk substrates, this invention has the effect of eliminating eccentricity caused by misalignment of the center hole diameters of the two disks. Applications are also possible, for example, a convex part or a concave part provided on the inner circumference or part of the outer part. Furthermore, a similar effect can be obtained by having both convex portions and concave portions on one substrate.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of an embodiment of the optical recording medium of the present invention. FIG. 2 is a sectional view showing the structure of a conventional optical recording medium. 1.2... Disc substrate 1α, 1b... Concave portion 2α, 2b... Convex portion 3... Recording layer 4...・・・・・・More than photosensitive resin adhesive

Claims (2)

[Claims] (1) In an optical recording medium with a laminated structure, the positioning of the two disk substrates to be laminated is performed on the whole or part of either the inner circumference or the outer circumference, or both. 1. An optical recording medium characterized by having convex portions and concave portions at opposing positions. (2) A claim characterized in that, in two disk substrates that are bonded together, the inner diameter of the center hole of one substrate differs from the inner diameter of the center hole of the other substrate by at least 0.2 mm. The optical recording medium according to item 1.