JPS63307983A - Production of optical recording medium - Google Patents

Abstract

PURPOSE:To prevent an error in reading, by recording data in the form of recessed and projected patterns on a transparent resin substrate, and discriminat ing the patterns by inks respectively having a high reflectance and a low reflectance. CONSTITUTION:Digital data is recorded in the form of recessed and projected patterns on a master plate by laser light or a mechanical engraving method, and based on the obtained master, a metallic mold 2 is produced by a metallic mold duplicating method. The mold 2 is fitted to an upper part of a compression molding device 1, a transparent resin substrate 3 is placed at a lower part, and compression molding is conducted to obtain a duplicate of the recessed and projected patterns of the mold 2. A low-reflectance ink 9 is preferably a black ink having a high optical transmission density, is charged into a recessed pattern ink charging part 12, and is hardened. Then, a high-reflectance ink 13 is applied to the recessed and projected patterns by a doctor coating method using a doctor knife 10 in a desired thickness to provide a high- reflectance ink layer 14. The ink 13 may be a gold ink containing a copper powder as a main constituent or a silver ink containing an aluminum powder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method of manufacturing a read-only optical recording medium.

[Prior art and its problems]

Optical recording has advantages over magnetic recording in that there is no contact between the recording medium and the head, and high-density recording is possible. As this optical recording medium, there are known ones that are read-only, those that allow additional writing, and those that are erasable and re-writable. Video discs and the like have already been put into practical use and are generally available on the market.

The manufacturing method for these read-only optical recording media involves recording a concavo-convex pattern on a matrix master using digital laser light or mechanical engraving.

Based on this, a mold for mass production (Stanno<) is created, and this mold is used to perform compression molding, injection molding, or photopolymer curing by injecting ultraviolet curable resin into the mold. A concavo-convex pattern is formed on a transparent resin plate using the method.

Next, a high reflectivity metal layer such as aluminum is formed on the entire surface of the replicated uneven pattern surface by vacuum deposition or sputtering, and the metal layer surface is adhered to a separately prepared four-finger substrate for readout. Manufacture dedicated optical recording media.

A series of these manufacturing methods are known.

41 material with an uneven pattern can be easily reproduced in large quantities by making a mold and is suitable for mass production, but the process of forming a metal layer with high reflectance requires a large amount of processing power at once. It is elegant and cannot be said to be suitable for mass production.

Furthermore, the reading method used in these optical recording media is to irradiate coherent light, typically a laser beam, onto a highly reflective uneven pattern formed in the medium, and to detect minute amounts of the reflected light. The signal is converted by a sensor using natural interference and read out as an information signal, and many errors occur during readout.

Although it is desirable that this readout error be thermally zero, sufficient reliability cannot be obtained as long as interference due to reflected light from the uneven portion is used. In addition, deformation of the unevenness, scratches, and dirt impede accurate reproduction of data, so care must be taken when handling and storing the media.

On the other hand, in other types of optical recording media, parts with high optical reflectance and parts with low reflectance are made of different materials, and a pattern is formed by the density of the difference in optical reflection. Optical recording media for recording information are known.

In this method, a general light source such as a tungsten lamp can be used as the readout irradiation light, and a manufacturing process signal with a large optical contrast is formed by reflection and absorption (no reflection) of the irradiation light. The reliability of data playback is superior to that of other methods.

A method for forming a light and shade pattern using optical reflection difference using this method is disclosed in Japanese Patent Application Laid-Open No. 60-66346, in which the above-mentioned two types of materials are formed in layers on a substrate. However, this is done by removing only 1- of one of the materials using an etching technique and exposing the other material on the back surface. However, this method requires the use of a photomask to form a resist pattern each time a light and shade pattern is formed, as well as etching, which complicates the manufacturing process and does not lend itself to mass production. Manufacturing costs are also high.

〔the purpose〕

The present invention was developed in view of the above-mentioned problems in the prior art. Digital information is recorded as a concave-convex pattern on a transparent resin base material using a method that uses a mold that is excellent in mass production. By distinguishing uneven patterns using inks with high reflectance and low reflectance, we created a dark and light pattern of digital information with a high contrast ratio using optical reflection differences, eliminating errors during reading. It is an object of the present invention to provide a method for manufacturing an optical recording medium that has high reliability in data reproduction, is excellent in mass production, and is low in manufacturing cost.

〔overview〕

The present invention uses a mold in which digital information is converted into a concavo-convex pattern and recorded, and the concave-convex pattern is reproduced on a transparent resin base material by a compression molding method, an injection molding method, or a photopolymer method, and then irradiated with light. Two types of ink with a large contrast ratio of reflection are prepared, and one type of ink is filled into the duplicated concave pattern portion using a doctor. After filling, an ink layer is formed on top of the ink layer by printing or coating using another type of ink, and the ink layer is adhered to a separately prepared substrate to produce an optical recording medium.

[Detailed description of the invention]

The present invention will be explained in detail below based on the drawings.

Digital information is recorded in advance as a concave-convex pattern on the master mold plate using a laser beam or mechanical engraving method using a known method.
Based on this, we created a mold (stambar) for mass production using a mold-making method such as the bottom casting method, and used one of the methods shown in Figures 1, 2, and 3 to mold transparent resin. Multiple uneven patterns are formed on the base material.

Figure 1 is a schematic diagram of a compression molding apparatus t1 using the compression molding method. After heating and compression molding using a press method, a replica of the concavo-convex pattern of the mold 2 is obtained on the transparent resin base material 3 by cooling.

FIG. 2 is a schematic cross-sectional view of an injection molding apparatus 4 using the injection molding method, in which a transparent resin base material 3 made by heating and melting transparent resin pellets 3 is injected into a mold 2 sealed under high pressure, and then cooled. Transparent 111111 base material 3 is removed from the mold 2 afterward.
The tlla of the uneven pattern of the mold 2 is obtained in this manner.

The transparent resin base material 3 in FIG. 1 has excellent optical transparency and desired mechanical and thermal properties.

Films made of polyvinyl chloride, polyvinylidene chloride, acrylic resin, polycarbonate, nylon, polyester resin, etc. are not particularly limited as long as they do not cause deformation or deterioration in subsequent steps.

Sheets, blocks, etc. can be used, and the transparent msj resin base material 3 in FIG. 2 is the same type of transparent resin pellet 3' as above.
Can be used by heating and melting it.

FIG. 6 is a sectional view of a photopolymer method using an ultraviolet curable resin.

A transparent resin substrate 6 is provided on the upper part of the mold 2, and an ultraviolet curing resin 5 is filled between the mold 2 and the transparent resin substrate 6, and the surface of the resin substrate 6 is irradiated with an ultraviolet lamp 7. , cure the ultraviolet curing cutter 1fIs.

After curing, the ultraviolet curable resin 5 and the transparent resin substrate 6 serving as a paste are peeled from the mold 2 to obtain a replica of the uneven pattern.

The ultraviolet curable resin 5 shown in Fig. 3 is one that has excellent optical transparency after curing, has desired mechanical and thermal properties, and does not cause deformation or deterioration in subsequent steps. There are no particular limitations, and acrylic materials may be used.

Liquid ultraviolet curable resin such as polyester can be used.

Further, as the transparent resin base material 6, a resin film or sheet used in the compression molding method shown in FIG. 1 can be used.

FIG. 4 shows the compression molding method shown in FIGS. 1, 2, and 3,
A cross-sectional view of a transparent concavo-convex pattern resin 8 reproduced in a mold 2 by an injection molding method and a 7 otobolimer method is shown.

The transparent resin substrate 6 exists only when the photopolymer method is used, and does not exist when using other molding methods.

FIG. 5 shows a method of filling the concave pattern portion of the transparent concavo-convex pattern resin 8 with low reflectance ink 9 using a doctor method. The low reflectance ink 9 is preferably a black ink with a high optical transmission density, but is limited to black ink as long as the optical transmission density is high and the optical contrast ratio with the high reflectance ink 13 shown in FIG. 6 is large. It's not something you can do.

The material of the doctor knife 10 is such that by bringing the doctor knife 10 into contact with the transparent concave-convex pattern resin 8 and moving it in one direction, the low reflectance ink 9 is scraped off and the transparent convex pattern part 11 is exposed. At the same time, any material such as rubber, ceramic, metal, or resin may be used as long as it has the effect of filling the concave pattern ink filling portion 12 with low reflectance ink.

FIG. 6 shows a method of filling a transparent uneven pattern resin 8 with a low reflectance ink 9 into a concave pattern ink filling part 12 using the doctor method shown in FIG. As one example, a method for producing a first substrate 150 is shown in which a high reflectance ink 13 is provided as a high reflectance ink 1114 at a desired thickness by a doctor coating method using a doctor knife 1o.

As a coating method, in addition to the above-mentioned methods, a bar code method, a spinner method, a roll coating method, a spray method, etc. can also be used.

Furthermore, as a method for providing the high reflectance ink layer 14, printing methods such as gravure printing, offset printing, and screen printing can also be used, and by using the printing method, designs such as logos, illustrations, etc. can be printed in addition to the uneven pattern area. It is also possible to perform printing at the same time, which simplifies the process.

As the high reflectance ink 13, gold ink containing mainly copper powder or silver ink containing aluminum powder can be used, but the low reflectance ink 9 has a high optical transmission density.
The optical contrast ratio is not limited to this as long as the optical contrast ratio is large.

FIG. 7 shows that the concave pattern ink filling portion 12 on the concave and convex pattern bright resin 8 is filled with low reflectance ink 9 by the method shown in FIG. 5 and cured, as shown in FIG. A high reflectance ink layer 14 is formed by a method and cured to form a light and shade pattern consisting of an optical reflection difference corresponding to digital information when viewed from the transparent uneven pattern resin 8 side, thereby forming the first substrate 15. Furthermore, it is an optical recording medium in which a second substrate 16 is adhered to the ink layer surface as a protective layer for protecting the ink 1- from external damage.

Adhesion methods include heat fusion or adhesives, and as the adhesive itself is sealed, any adhesive can be selected, except for solvent-based adhesives.1 For example, acrylic, epoxy, etc. A thermosetting type can be used.

The second substrate 16 may be made of any desired mechanical material.

It is not particularly limited as long as it has thermal properties.

The same resin sheet or film used in the compression molding method shown in FIG. 1 related to the present invention may be used, and for the ground pressure, a resin sheet or film made of polyethylene, polypropylene, ABSII resin, etc., or a metal plate may also be used.

Furthermore, the thickness of each layer of the optical recording medium shown in FIG. The shape pattern ink filling section 12 is filled with low reflectance ink 9.

By forming high reflectance ink l1i14 with high reflectance ink 13 and overlapping both, a shading pattern consisting of an optical reflection difference is formed. year.

It is also possible to form a light and shade pattern consisting of an optical reflection difference using low reflectance ink in areas where high reflectance ink is used.

〔Example〕

The dot size is 10 μm square, and the unevenness level is 5 μm.

Using a mold having a concavo-convex pattern with a dot pitch of 10 μm, the concave-convex pattern was replicated on a transparent acrylic resin with a thickness of 0.5 μm by compression molding.

Next, black ink is poured onto the uneven pattern surface of the transparent acrylic resin, and the black ink is scraped off with a doctor knife made of Teflon resin, so that the concave pattern areas are filled with black ink, and the convex pattern areas are filled with the transparent acrylic resin. The resin surface was exposed.

This was placed in a drying oven and dried at 80° C. for 30 minutes to cure the black ink.

Next, a silver ink layer mixed with aluminum powder was used to form a silver ink layer on the entire surface of the transparent acrylic resin surface filled with black ink using a doctor coating method, and the ink was dried again for 80° and 30 minutes in a drying oven.・Curing was performed.

Next, white polyvinyl chloride having a thickness of 0.5 wam prepared separately and the surface of the silver ink layer were adhered with a thermosetting adhesive, and the uneven pattern of the mold corresponded in the optical recording section. An optical recording medium having a light and shade pattern with good contrast consisting of optical reflection differences was obtained.

〔Effect of the invention〕

According to the present invention, a mold with excellent mass production ability can be used to create a concavo-convex pattern compatible with digital information in the production of read-only optical recording media that record information using the contrast between optically high reflectance and low reflectance. 4. on the transparent resin base material using the method used. Using simple methods such as printing and coating methods, it is possible to create uneven patterns using low-reflection ink and high-reflection ink into a light and shade pattern consisting of optical reflection differences, and this method uses etching. Also, there is no need for a metal layer deposition process, making it extremely easy to mass-produce.

As a result, manufacturing costs can be reduced.

Note that since the ink used in the present invention is not subjected to many chemical treatments, it can be selected from a wide range of materials, and when the ink 4 is formed by a printing method.

At the same time, Shin printing can be done, which simplifies the process.

Furthermore, in order to form a high-contrast shading pattern made up of optical reflection differences, instead of using coherent light such as a laser beam, we irradiate it with general tungsten light, LED, etc., and use a light receiving element such as a CCD. The reading device can also be simplified because it can be read with

Furthermore, since it is not necessary to use laser light for reading, there is no influence of birefringence of the transparent resin base material, and a wide range of materials can be selected.

[Brief explanation of the drawing]

1 to 3 are schematic diagrams of the molding apparatus. 4 to 7 are enlarged cross-sectional views of each step of the present invention. 1: Compression molding device 2: Mold 3: Transparent resin base material 3': Transparent resin pellet 4: Injection molding device 5: Ultraviolet curing resin 6: Transparent resin substrate 7: Ultraviolet lamp 8: Transparent uneven pattern resin 9: Low reflectance ink 10: Doctor knife 11: Transparent convex pattern section 12: Concave pattern ink filling section 13: High reflectance ink 14: High reflectance ink layer 15: First substrate 16: Second substrate

Claims (1)

[Claims] (1) Using a mold in which digital information was converted into a concave-convex pattern and recorded, the concavo-convex pattern was reproduced on a transparent resin substrate, and two types of ink with a high contrast ratio of reflection to irradiation light were prepared. , After filling one of the inks into the duplicated concave pattern portion using a doctor method, a layer of the other of the inks is provided on the surface of the transparent resin base material having the concavo-convex pattern. The process is characterized by creating a first substrate in which the uneven pattern is changed to a light and dark pattern, and bonding the ink layer side of this first substrate to a separately prepared second substrate using heat fusion or adhesive. A method for manufacturing an optical recording medium.