JPH0757303A - Production of optical information recording carrier and information recording carrier - Google Patents

Abstract

PURPOSE:To efficiently initialize the disk-shaped optical recording information carrier which has phase transition type recording films and is erasable in initialization of the carrier and to prevent the thermal deterioration of resins protecting the recording films. CONSTITUTION:A substrate constituted by forming the recording film 4 on a replica substrate 2 is heated and initialized by an initializing device using a laser beam 9 and an over coat layer 5 is added onto the recording film 4 after the initialization. Further, a hot melt resin 6 is applied thereon. Two sheets of the substrates after application of the hot melt resins 6 thereon are superposed on each other as a pair by positioning the surface coated with the hot melt resins on the inner side and are finished to one sheet of the both side disk by applying a pressure on the substrates 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention shows a method for efficiently initializing an erasable disc-shaped optical record information carrier having a phase change recording film, and manufacturing the optical record information carrier. Used in the process.

[0002]

2. Description of the Related Art An erasable disk-shaped optical record information carrier (hereinafter referred to as an optical disk) having a phase-change recording film has heretofore been capable of direct additional recording without requiring a process of erasing already recorded information. It has already been commercialized as a direct overwritable optical disc. This optical disc has a recording film that undergoes a reversible phase transition, and stores information by a phase change between an amorphous state and a crystalline state.
Further, information is read (read) by using the phase state as a difference in optical reflectance.

This optical disk is manufactured by the manufacturing process as shown in FIG. In the molding process, the replica substrate 2 onto which the concave-convex pattern of the stamper 1 is transferred by injection molding is added with the hard coat layer 3 on the surface of the replica substrate 2 in the hard coat process as needed, such as in a use environment.
Due to this hard coat layer 3, the surface hardness of the replica substrate becomes about H in terms of pencil hardness, and the surface resistance value is 10 ¹⁵ Ω.
The conductivity is improved to a certain extent. Thereafter, the hard-coated replica substrate is formed with the recording film 4 on the substrate by a sputtering method in a film forming process. The structure of the recording film 4 is four layers as shown in FIG. 3, and the recording layer 4a is made of GeTeSb.
And a dielectric layer 4b made of ZnS-SiO ₂ on both sides thereof.
And 4c and a reflection layer 4d made of Al alloy.

The structure of the recording film 4 is such that a dielectric layer and a reflective layer are arranged on both sides of the recording layer to protect the recording film and to have an appropriate heat diffusion to realize direct overwrite.

An overcoat layer 5 made of UV resin or the like is added to the formed substrate in order to protect the recording film 4 in the overcoat process. The substrates to which the overcoat layer 5 was added were coated with the hot melt resin 6 in the laminating step, and then the two substrates were paired and the surfaces coated with the hot melt resin 6 as an adhesive were laminated inside. After that, pressure is applied to finish the single-sided double-sided disk 8.

The recording film 4 of this disk 8, especially the recording layer 4
Since a is in an amorphous state and has a low reflectance, it cannot be used in an optical information recording / reproducing apparatus. For this reason, conventionally, in an optical disk having a phase change recording film, each track or a plurality of tracks are collectively irradiated with a laser beam 9 to perform initialization, and the state of the recording layer is changed from an amorphous state to a crystalline state to obtain a reflectance. Is rising. In the initialization process, initialization is performed using an initialization device as shown in FIG. A high power laser 10 having a power of 1 W or more, such as an Ar laser or a semiconductor laser, is used as a heat source, and the emitted beam A of the laser is passed through an optical pickup 11 having an objective lens, a mirror, etc., on the recording film surface of the optical disk 8. About φ20 ~ 3
Focused irradiation is performed as a beam B having a diameter of 0 μm. Further, by moving the optical pickup 11 in the radial direction of the optical disc 8 by the moving device 12, the irradiation position of the beam B on the optical disc can be changed. The position of the optical pickup is detected by the linear scale 13, and the position data is input to the control circuit 14 configured by a microcomputer or the like. The control circuit 14 is a turntable motor 15
And the moving device 12 to control the turntable motor 15
Since the erasing condition of the recording film 4 of the upper optical disk 8 changes depending on the linear velocity, the recording film 4 is irradiated with the light beam at a constant linear velocity (CLV) and at a constant feed pitch.

With this initialization device, the temperature is raised above the crystallization temperature of the recording film to transition from the amorphous state to the crystalline state.

In this conventional example, the initialization was performed in the CLV state, but the initialization can be similarly performed even if the intensity of the irradiation beam B is controlled in the state of a constant rotation speed (CAV).

[0009]

In the conventional example, the optical disk having the phase change recording film was initialized after the bonding in the manufacturing process. However, since the overcoat layer 5 is provided on the recording film 4, the heat of the laser beam irradiated at the time of initialization is propagated to and absorbed in the overcoat layer 5, so that the heating and heating can be efficiently performed. In addition, there is a problem that the overcoat material itself is thermally damaged by being heated and the adhesiveness with the recording film is deteriorated, and also the overcoat material is gasified by thermal decomposition.

[0010]

In the present invention, initialization is performed by heating a substrate on which a recording film is formed on a replica substrate in a film forming process, and an overcoat layer is added on the initialized recording film. Then, a hot-melt resin is further applied, and the two substrates after the hot-melt resin are applied are paired and the hot-melt resin-coated surface is placed inside and the two substrates are stacked.
By applying pressure to the superposed substrates, a single double-sided disk is finished.

[0011]

According to the present invention, the initialization by heating the optical disk is performed on the substrate after film formation before providing the overcoat layer, so that heat absorption by the overcoat layer is eliminated as compared with the prior art, and the laser light at the time of initialization is used. By heating and heating efficiently, and by adding the overcoat resin to the substrate after initialization,
It is possible to improve the adhesion of the overcoat resin to the recording film. In addition, since the overcoat resin, which is the protective layer of the recording film, is applied after initialization, the overcoat resin is not thermally damaged, so that strong adhesion to the recording film can be maintained. I have.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a manufacturing process of an optical disc in the embodiment. The same processes as those in the conventional example are designated by the same reference numerals and the description thereof will be omitted.

The substrate on which the recording film 4 has been formed in the film forming step is initialized by being irradiated with the laser beam 9 in the initializing step. At this time, the state of the recording layer 4a is changed from the amorphous state to the crystalline state, and the reflectance is increased.

At this time, the initialization device used is the one shown in FIG. 4, which is the same as the conventional example. However, since the heat diffusion is small, if the light output of the laser 10 is the same, the linear velocity of the CLV can be set to 1.5 times or more that of the conventional example to perform the initialization. Alternatively, it can be realized by increasing the laser spot area by 1.5 times.

The initialized substrate is an overcoat layer 5 made of UV resin for protecting the recording film in the overcoat process.
Is added. The substrate to which the overcoat layer 5 is added is coated with the hot melt resin 6 in the laminating step, and then the substrate 2 is formed.
After a pair of sheets are stacked with the surfaces coated with the hot melt resin facing inward, pressure is applied to finish one double-sided disk 7.

In the above embodiment, the optical disk is described as an example, but it is obvious that the invention is not limited to the shape and can be applied to a recording medium having a card shape, a drum shape, a tape shape, or the like. Also, although it has been explained about the phase change recording material, it can be applied by adding magnetic field means also to the initialization of the reversible recording film having the recording principle using heat and the magneto-optical recording material which requires both heat and magnetic field. Is.

[0017]

As described above, by using the present invention, initialization can be efficiently performed, and even if the same laser power is applied as compared with the conventional initialization, the line can be irradiated with light. It is possible to increase the speed, and as a result, the time required for initialization per sheet can be reduced to 70% or less compared to the conventional case, and it is possible to greatly reduce the time.

By applying the overcoat resin, which is a protective layer of the recording film, after the initialization, the overcoat resin is not thermally damaged, the original characteristics are maintained, and strong adhesion to the recording film is maintained. It is possible to supply high quality, long life optical discs that can maintain their performance.

[Brief description of drawings]

FIG. 1 is a process diagram of an optical disc manufacturing process according to an embodiment of the present invention.

FIG. 2 is an optical disk manufacturing process diagram in a conventional example.

FIG. 3 is a diagram showing a structure of a recording film.

FIG. 4 is a block diagram of an initialization device.

[Explanation of symbols]

 1 Stamper 2 Replica Substrate 3 Hard Coat Layer 4 Recording Film 4a Recording Layer 4b 4c Dielectric Layer 4c Reflective Layer 5 Overcoat Layer 6 Hot Melt Resin 7 Double-sided Optical Disk Made by Manufacturing Process of the Present Invention 8 Manufacturing Process of Conventional Example Double-sided optical disc made with 9 Laser light 10 Laser 11 Optical pickup 12 Moving device 13 Linear scale 14 Control circuit 15 Turntable motor

Claims (4)

[Claims] 1. A process for producing an optical information recording carrier, comprising a substrate and a recording film which causes a reversible phase transition on the substrate, and a resin layer on the recording film. A method for producing an optical information recording carrier, characterized in that the recording film is heated before being coated with the composition to transform the recording film from an amorphous state to a crystalline state. 2. When heating the recording film, the laser is narrowed down to a predetermined spot, a relative velocity is generated between the record carrier and the laser, and the spot position on the recording film is scanned to heat the recording film. Item 2. A method for manufacturing an optical information recording carrier according to item 1. 3. A process for producing an optical information recording carrier, comprising a base material and a recording film which causes a reversible phase transition on the base material, and a resin layer on the recording film. An optical information recording carrier, characterized in that the recording film is heated before being coated with the material to transform the recording film from an amorphous state to a crystalline state. 4. The optical information record carrier according to claim 3, wherein an ultraviolet curable resin is used as the resin.