JPS60256937A - Optical information carrier disc - Google Patents

Abstract

PURPOSE:To improve the adhering strength between a disc base and a protection base by providing an information medium layer to a face having a track pit of the disc base one face of which the track pit is formed and adhering the protection base of the same shape as the said base while opposing the track pit. CONSTITUTION:The track pit 2 for guiding laser beam is formed incorporatedly to one face of the disc base 1. The recording medium layer 3 is provided to the face of the track pit 2 of the base 1. The protection base 6 to protect the medium layer 3 is adhered to the base 1 via an adhesive 7. Entirely the same base as the base 1 is used for the base 6, an adhesive 7 is bonded directly to the track pit 8 formed incorporatedly with the base 6 and the bonding force is improved by the ruggedness of the track pit 8. Thus, the adhering strength between the disc base 1 and the protection base 6 is improved.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an optical information carrier disk (hereinafter simply referred to as a disk) that optically records and reproduces information by providing an information medium layer on a disk-shaped transparent substrate. It is related to the structure of

Conventional configuration and its problems Traditionally, track grooves are formed on one side of a disc-shaped transparent substrate, and an unrecorded recording medium layer is formed on the surface of the track groove, or a predetermined information signal is recorded in advance. Using a disk substrate in which an information medium layer is provided on a transparent substrate, such as one in which a reflective layer is formed on the recorded uneven pits, the surfaces of the information medium layer are arranged to face each other, or simply a protective substrate is placed on the information medium layer. 2. Description of the Related Art Optical recording and reproducing devices have been put into practical use that use disks bonded together to face each other and record or reproduce information using laser light.

Resin materials such as acrylic and polycarbonate are often used as the disk substrate in these disks, but resin materials have the property of undergoing relatively large expansion and contraction deformations due to changes in humidity and temperature. In addition, when using a disc made by pasting two substrates together, humidity and
Distortion occurs due to sudden changes in temperature or changes in humidity and temperature over a long period of time, and it has the disadvantage of easily peeling off from the bonded surface.

OBJECTS OF THE INVENTION The present invention seeks to eliminate the above-mentioned drawbacks.
Improves the bonding strength between the disk substrate and the protection substrate,
At the same time, the objective is to obtain a practical disc at low cost.

Structure of the Invention The present invention provides an information medium layer on the track groove surface side of a disk substrate having track grooves integrally formed on one surface, and a substrate having the same shape as the disk substrate to protect the information medium layer. By bonding the two substrates together as protective substrates so that their track grooves face each other, the disk is designed to improve the bonding strength of the two substrates and to reduce costs.

Description of examples Embodiments of the present invention will be described below with reference to the drawings.

The figure is a sectional view of a disk in one embodiment of the present invention.

In the figure, reference numeral 1 denotes a disk substrate, on one surface of which a track groove 2 for guiding laser light is integrally formed. 3 is a recording medium layer provided on the surface of the track groove 2; 4 is the track groove 2;
5 is a center hole of the disk substrate 1, which is an annular groove formed when the disk substrate 1 having the above-mentioned shape is obtained by integral molding. Reference numeral 6 denotes a protective substrate for protecting the recording medium layer 3, which is bonded to the disk substrate 1 via an adhesive 7.

゛In the case of a recess-only disc in which a reflective layer is formed by providing a concavo-convex focus in advance, the trunk groove 2 serves as the concave-convex bit, and the recording medium layer 3 serves as the reflective layer.

In the configuration shown in the figure, the protection board 6 uses the same board as the disk board 1. For this reason, the track groove 8 integrally formed on the protective substrate 6 is directly bonded with the adhesive 7, and the unevenness of the track groove 8 improves the adhesive force.

The specific dimensions of the track groove are generally groove width 0.6 to 1.
Since the unevenness is about μm, the groove depth is about 0.06 to 0.1 μm, and the groove pitch is 1.5 to 3 μm, the adhesive force per unit area when using the same material adhesive is higher than that of a mirror surface. It is possible to obtain approximately three times as much adhesive strength.

In addition, by using the same substrate as the disk substrate 1 and the protection substrate 6, the disk substrate 1 can be molded in large quantities by injection molding, for example, without affecting the external appearance, such as a substrate with large birefringence that is inappropriate as the disk substrate 1. The disk substrate 1 can be effectively used by using a substrate with defects in the range as the protective substrate 6. Effects of the Invention As described above, according to the present invention, it is possible to use the same substrate as the disk substrate on which track grooves are integrally formed. By using it as a protective substrate, the bonding strength of two substrates can be improved.For example, if a disk substrate has a problem with its appearance but has a characteristic problem, it can be used as a protective substrate. It can be used effectively and is cost effective.

[Brief explanation of the drawing]

The figure is a sectional view of an optical information carrier disk in one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Disk substrate, 2...Track groove, 3...Recording medium layer, 6...Protective substrate, 7...Adhesive .

Claims (1)

[Claims] An information medium layer is provided on the side where the trunk groove is present of a disk substrate having a track groove integrally formed on one side;
An optical information carrier disk in which a protective substrate having the same shape as the disk substrate is bonded together so that their track grooves face each other.