JPH03187038A - Production of optical recording medium - Google Patents

Abstract

PURPOSE:To execute molding at high-speed by eliminating the need for heating at high temp. and to reduce deformation of the moldings in the production process of an optical recording medium in which recording/reproducing can be performed with laser beam by applying a liquid which can dissolve the transparent substrate on the substrate, pressing the substrate with a die to form guide grooves. CONSTITUTION:On a transparent substrate such as acryl, polycarbonate or vinyl chloride, a solution which can dissolve the substrate is applied, for example, benzene, toluene, xylene, chloroform, chlorobenzene, and methylen chloride. Then a stamper composed nickel or formed with pregroup and preformat is pressed onto the transparent substrate to transfer the pattern. Then an optical recording material is deposited on the substrate and properly processed to obtain the optical recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing an optical recording medium that can be optically written to, read from, or written to, read from, and erased.

[Prior art and its problems] At present, magnetic recording systems are being produced and used in large quantities as hard disks and floppy disks as external storage devices for electronic computers, magnetic tapes for music, magnetic cards, and the like. As described above, magnetic recording systems are deeply permeated into social life, but as their application fields expand, both manufacturers and users are looking to add higher functionality to recording systems. is now in demand. The primary requirement is due to the small amount of information that can be held in current magnetic recording media. Of course, the lack of memory information here refers to not only the main information that is originally necessary;
It can also be said that it is lacking in the sense of recording redundant information that functions to protect the main information.

Under these circumstances, an optical recording system has been proposed as a recording medium with a larger storage capacity.

This optical recording medium has a huge storage capacity and is considered to be very effective as an external storage device or auxiliary storage device for a computer, or as a storage medium for personal information.

Currently proposed optical recording media include read-only, additionally writable optical discs or optical cards, and media from which information can be erased.

Here, read-only optical recording media include DAD (digital disc), which is typified by CD (compact disc).
Examples include audio discs), CD-ROMs, and ROM-type optical cards. That is, information is written on the recording medium when it is manufactured, and the information is read out and used by the user using a semiconductor laser or the like. Although the information recorded in these is fixed information that cannot be written with new information, it has excellent information security and excellent recording stability.

Direct read-after-write (DRAW) is already a method for recording optically writable recorded information.
), a wide range of recording principles and recording materials have been proposed. That is, this is so-called heat mode recording, in which information is recorded by physical and chemical changes in the recording material, such as transition, expansion, melting, decomposition, and phase change, using emitted light from a light source such as a laser as a heat source. Examples of materials used in this recording method include low melting point metals such as tellurium and bismuth, alloys and oxides containing these as main components. These recording materials are mainly produced using vacuum techniques such as vacuum evaporation, sputtering, and plasma CVD.

Another example is an organic dye. Organic dyes have the advantage of being able to freely design their absorption spectra to match the wavelength of the light source used for optical recording.
It has mass-producibility and can be coated by dispersing it in an appropriate dispersant.

As erasable (E-DRAW) type optical recording media, magneto-optical recording systems, phase change types, etc. have been proposed.

The former is a method in which pits that are magnetically recorded using a laser as a heat source and an external magnetic field are optically read out using the magneto-optic effect of the recording material. Examples of such recording materials include rare earth-transition metal alloys such as terbium-iron-cobalt and gadolinium-terbium-iron, and metal oxides containing additives such as yttrium iron garnet and ferrite. These recording materials are also mainly produced using vacuum techniques such as vacuum evaporation, sputtering, and plasma CVD, and it is still difficult to achieve high densities due to the instability of read signals. The phase change optical recording method is
This is a recording method that records by irradiating the recording material with laser beams with different outputs and changing the phase of the material due to the difference in temperature rise.Reading is done by converting changes in the optical properties of the material, such as refractive index, due to the phase change into light intensity. Examples of phase-change recording materials that can be used include alloys containing antimony, tellurium, selenium, indium, etc. as main components. These recording materials are also mainly produced using vacuum technology.

Here, in an optical recording medium, in order to correctly scan (track) a laser beam, preformatting is required in order for a guide groove (pregroup) to quickly move to a requested track. Conventionally, in order to form these, a method has been used in which a stand bar is made of metal such as nickel, and the stand is heated in close contact with a transparent substrate made of acrylic resin, polycarbonate, etc., thereby deforming the base material.

However, this method largely depends on the physical properties of the base material, such as the melting point, and generally must be carried out at a high temperature of 120° C. or higher and under high pressure conditions.

Further, due to the lack of flexibility of the base material, it is not possible to carry out the process continuously. Therefore, when attempting to produce in large quantities, it is difficult to shorten the time and it is also difficult to reduce costs.

As described above, although optical recording media have a large storage capacity, they also have the problem that when trying to mass produce them, it is difficult to shorten the time and it is also difficult to reduce costs.

[Scheme S to be solved by the invention] The present invention has been devised in view of the problems of the prior art as described above, and relates to DRAW and E-DRAW type optical recording media, and it is related to DRAW and E-DRAW type optical recording media, and The main objective is to provide a method for manufacturing an optical recording medium with high performance.

[Means for Solving the Problems] The present invention provides a method for manufacturing DRAW type and E-DRAW type optical recording media, in which a solution capable of dissolving the transparent substrate is applied onto a transparent substrate, and then a mold is pressed. The above problem is solved by including the step of forming a guide groove.

The present invention will be explained in detail below.

The method for manufacturing the optical recording medium of the present invention is as follows.

First, a solution capable of dissolving the transparent substrate is coated onto a transparent substrate made of acrylic, polycarbonate, vinyl chloride, polyester, or the like by a method such as barcoding, spin coating, or roll coating. The solutions to be applied here include benzene, toluene, xylene, chloroform, chloropene methylene chloride, ethylene chloride, methyl ethyl ketone, cyclohexane, acetic acid, benzyl alcohol, methanol, ethanol, etc. for acrylic resins, and acetone, ethanol, etc. for polycarbonate resins. Benzene, toluene, xylene, chloroform, DMF, methyl acetate, ethyl acetate, etc. For vinyl chloride resins, toluene, xylene, acetone, cyclohexanone, chloroform, methylene chloride,
Methyl acetate, DMF, etc. can be used, and for the polyester resin, phenol, benzene, toluene, chloroform, chlorobenzene, etc. can be used. In this way, the flexibility of the surface of the transparent substrate is improved.

A pregroup or a stamper on which a pregroup and preformat made of nickel or the like is formed is brought into close contact with the transparent substrate and pressed, and the shape is transferred to form the pregroup and preformat.
Form into layers. Here, it may be heated if necessary. At this time, if a method such as a roll press is used, it can be formed in large quantities and quickly.

Furthermore, an optical recording medium can be obtained by depositing an optical recording material thereon and performing necessary processing.

[Function] By applying a solution capable of dissolving the transparent substrate as described above and improving the flexibility of the surface of the transparent substrate, it becomes possible to form a bottom shape at a low temperature. Furthermore, since high-temperature heating is not required, stable quality can be obtained with less deformation such as distortion of the transparent substrate.

[Example 1] Benzene is coated with a bar code onto an acrylic resin plate with a thickness of 700 tIm produced by a casting method.

A nickel stamper produced by electroforming is closely attached and pressed onto the surface of this resin plate. Here, a guide groove and a preformat are formed by unevenness on the stamper. Furthermore, in this state, it is heated at 20 to 80°C for 5 minutes, and after cooling, the pressure is decompressed. In this way, the guide grooves and preformat information on the standber are transferred to the surface of the acrylic resin plate.

FIG. 1 shows the temperature dependence of the molding rate of the resin plate thus obtained.The manufacturing method according to the present invention allows molding at a temperature of 50°C or higher.

[Comparative Example 1] A nickel stamper produced by electroforming is closely attached and pressed onto the surface of an acrylic resin plate having a thickness of 700 μm produced by a casting method. Here, a guide groove and a preformat are formed by unevenness on the stamper. Further, in this state, it is heated at 100 to 150°C for 10 minutes, and after cooling, the pressure is decompressed. In this way, the guide groove and preformer gutter information on the standber are transferred to the surface of the acrylic resin plate.

Figure 2 shows the temperature dependence of the molding rate of the resin plate obtained in this way.
A temperature of 0°C or higher is required.

[Example 2] Toluene is coated with a barcode onto a polycarbonate resin plate having a thickness of 400 μm. A nickel stamper produced by electroforming is attached to the surface of this resin plate by vB and pressed. Here, a guide groove and a preformer 7 are formed by unevenness on the stamper. Furthermore, in this state, 20 to 80
Heat at ℃ for 5 minutes, cool and depressurize. In this way, the guide grooves and preformat information on the stamper are transferred to the surface of the polycarbonate resin plate.

FIG. 3 shows the temperature dependence of the molding rate of the resin plate thus obtained. The manufacturing method according to the present invention allows molding at a temperature of 60° C. or higher.

[Comparative Example 2] A nickel stamper produced by electroforming is closely attached and pressed onto the surface of a polycarbonate resin plate having a thickness of 400 μm.

Here, a guide groove and a preformat are formed by unevenness on the stand bar.

Further, in this state, it is heated at 130 to 160°C for 10 minutes, and after cooling, the pressure is decompressed. In this way, the guide grooves and preformat information on the standbar are transferred to the surface of the polycarbonate resin plate.

Figure 4 shows the temperature dependence of the molding rate of the resin plate obtained in this way.
0°C or higher is required.

[Effect of the invention] The effects of the present invention will be described below.

By applying a solution capable of dissolving the transparent substrate onto the transparent substrate and then pressing the transparent substrate in close contact, there is no need for high-temperature heating. This makes it possible to speed up the molding process. Furthermore, since high-temperature heating is not performed, a stable product with less deformation of the molded product can be obtained.

[Brief explanation of drawings]

Figures 1 and 2 show the temperature dependence of molding rate in Example 1 and Comparative Example 1 using acrylic resin, respectively. Figures 3 and 4 show the temperature dependence of the molding rate in Example 2 and Comparative Example 2 using polycarbonate resin, respectively. Application Representative of Toppan Printing Co., Ltd. &A ('C) Figure 3 Wisdom 5 Ram 戊 (0C) Figure 4

Claims (1)

[Claims] A method for manufacturing an optical recording medium capable of recording and reproducing information using a laser beam, characterized by comprising a step of applying a solution capable of dissolving the transparent substrate onto a transparent substrate, and then pressing a mold to form a guide groove. Method for manufacturing optical recording media