JPH06162572A - Optical recording medium and its production - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium without defect in coating films in which information with respect to the medium itself is written with laser light, and to obtain its production method. CONSTITUTION:This medium is formed by successively depositing a recording layer containing a coloring matter and a reflecting layer on a transparent resin substrate. After information which can be read by reflection or transmission of light is written in the medium by removing the reflecting layer from the reflecting layer, a protective layer is formed thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium, and more particularly to a single plate type high reflectivity write-once type optical recording medium having a recording layer of a dye capable of recording a large amount of information. The present invention relates to written matter and a manufacturing method thereof.

[0002]

2. Description of the Related Art A single plate type recordable and commercially available compact disc (hereinafter abbreviated as CD) in which a dye is used as a recording layer, a metallic reflecting layer is provided on the recording layer, and a protective layer is further provided thereon.
An optical recording medium compatible with a player, a CD-ROM player or a CD-I player is, for example, Optical D
ata Storage 1989 Technical Digest Series Vol.1 45
(1989), JP-A-2-132656, JP-A-2-168446 and the like.

Generally, an optical recording medium, which includes:
For example, information about the medium (medium information) such as the name of the manufacturing company, the name of the manufacturing factory, the manufacturing line, the date of manufacture, etc. is described. And this information was usually encoded and read by the human eye. However, when these media are used recently, these information may be read by a writer or reader to manage the media. When reading with a writer or a reader, it is general to read by reflecting or transmitting normal light. Then, one of the simplest methods for writing information to be read by such a method is a method of writing the information by a bar code or the like by removing the reflective layer with a laser or the like.

A method for writing such information on a read-only optical disc is described in Japanese Patent Publication No. 2-56750. This document describes a method of writing information on a read-only optical disc having a structure of substrate / reflection layer / protection layer by irradiating laser light through the substrate or protection layer. However, this method can be applied to substrate / organic dye layer /
When applied to a write-once type optical recording medium composed of a reflective layer / protective layer, in writing a large area such as a bar code, the reflective layer and the organic dye layer that have absorbed the laser light generate a considerable amount of heat. It has been found that deterioration of the protective layer occurs, deteriorating the environmental resistance characteristics of the medium.

However, although we have studied the medium information writing by the bar code after forming the reflective layer and then forming the protective layer, when removing the reflective layer, dust, fine particles, dust accompanying the removal are removed. It has been found that dust such as dust is generated, and the generated dust adheres to the reflective layer and adversely affects the conventional method. That is, since the reflective layer is usually a very thin and soft metal film,
Attempting to remove dust only damages the metal reflective film very easily, and removal of dust adhering to the reflective layer was substantially difficult. Then, if a protective layer is next formed on the reflective layer while the removal of dust is incomplete,
It was found that coating film defects caused by dust occur.
Such a coating film defect not only deteriorates the appearance of the medium, but also causes a fatal problem such as cracking or peeling of the protective layer in the vicinity of dust adhesion in the evaluation of environmental resistance. I found it.

[0006]

DISCLOSURE OF THE INVENTION The present inventors write information on the origin of a medium by forming a reflective layer on an optical recording medium comprising a recording layer, a reflective layer and a protective layer and then removing the reflective layer. As a result of various studies to improve the coating film defect due to the dust as described above, the present invention has been completed.

[0007]

That is, according to the present invention, a recording layer containing a dye and a reflective layer are sequentially laminated on a transparent resin substrate, and at least a part of the reflective layer is formed on the reflective layer. An optical recording medium in which readable information is written by reflection or transmission of light by removing, and then a protective layer is further laminated, preferably an optical recording medium in which information is written by a bar code. Is.

Further, according to the present invention, a recording layer containing a dye and a reflective layer are sequentially laminated on a transparent resin substrate, and at least a part of the reflective layer is removed from the laminated reflective layer to obtain an optical layer. Is a method for manufacturing an optical recording medium in which readable information is written by reflection or transmission, and then a protective layer is further laminated, and preferably, a method for manufacturing an optical recording medium in which information is written by a bar code, Preferably, it is a method of manufacturing an optical recording medium in which information that can be read by reflection or transmission of light is imprinted with a laser under the ventilation, and information that can be read by reflection or transmission of light is laser. A method for producing an optical recording medium, in which air is blown from the outer circumference of the disk to the inner circumference when engraving with the laser irradiation part, and the linear velocity of the draft is 1 m /
and a method of producing an optical recording medium in which the gas to be blown contains an inert gas. The present invention, in particular, when engraving information that can be read by reflection or transmission of light by means of an under-laser laser, air is blown from the outer circumference of the disk to the inner circumference of the laser irradiation part to remove dust generated by laser light irradiation. By removing it, it enables effective writing. Especially, it is a very effective method when writing a large area where information is written by a bar code using a laser beam. Is.

The transparent resin substrate used in the present invention is preferably one that transmits light for recording and reading signals. It is desirable that the light transmittance is 85% or more and the optical anisotropy is small. A preferable example is a substrate using a thermoplastic resin such as an acrylic resin, a polycarbonate resin, a polyamide resin, a vinyl chloride resin, or a polyolefin resin. Among these, injection-molded resin substrates of acrylic resin, polycarbonate resin, and polyolefin resin are preferable from the viewpoint of mechanical strength of the substrate, easiness of imparting a groove or reproduction-only signal, etc., and economical efficiency, and polycarbonate resin is particularly preferable. Most preferred is a resin substrate. The shape of these substrates may be plate-like, film-like, circular, or card-like. Grooves for controlling recording positions are formed on the surfaces of these substrates. Further, it may have a pit or the like for some reproduction-only information. Such grooves and pits are preferably added when a substrate is made by injection molding or casting.

In the optical recording medium of the present invention, a recording layer containing a dye, a reflective layer and a protective layer are sequentially laminated on the transparent resin substrate. The dyes used are polymethine dyes, phthalocyanine dyes, naphthalocyanine dyes, naphthoquinone dyes,
Examples thereof include dyes having absorption in the oscillation wavelength range of a semiconductor laser, such as azulene dyes and dithiol metal complex dyes. These dyes may be substituted with various kinds of substituents in order to control the solubility in a solvent and for recording characteristics. Further, these dyes may be used alone or in combination of two or more. Among these dyes, phthalocyanine dyes and naphthalocyanine dyes are preferable in consideration of dye durability.

In the present invention, the above-mentioned recording layer containing the dye can be usually formed by a coating method such as spin coating, spraying or dipping. A solvent that does not damage the resin substrate when the dye is formed by a coating method,
That is, the dye may be dissolved and applied in a solvent that does not substantially dissolve the substrate resin. In the present invention, the thickness of the recording layer is usually preferably 50 to 200 nm.

In the present invention, after forming the recording film, the outermost recording film may be removed with a solvent in order to improve the adhesion of the protective layer. When forming a recording layer containing a dye, a resin such as nitrocellulose, ethyl cellulose, an acrylic resin, a polystyrene resin, a urethane resin, a leveling agent, an antifoaming agent, etc. in addition to the above-mentioned dyes impairs the effects of the present invention. It can also be used together within a range that does not exist.

In the present invention, the reflective layer provided on the recording layer is usually preferably a metal thin film. In the present invention, it is preferable that the reflectance on the groove of the medium is 60% or more in consideration of compatibility with a normal CD player. Preferred metals include aluminum, gold, silver, copper, platinum, nickel and the like, and alloys containing these metals as one component. The reflective layer of these metals can be formed by a method such as vapor deposition and sputtering. The thickness of these reflective layers is usually preferably about 500 to 2000A. Of course, it is preferable to form the reflective layer over the groove portion.

In the present invention, at the stage of forming the reflective layer, at least a part of the reflective layer is removed to write information about the origin of the medium (medium information). As the recording means used at this time, for example, a laser marker using a YAG (1064 nm) laser, a second harmonic (532 nm) of a YAG laser, a carbon dioxide gas laser, or the like as a light source is preferable.
By using these laser markers and irradiating light in a pulsed or continuous manner, the irradiation conditions can be appropriately selected to remove the metal reflection layer and the recording layer.

Contents to be written include medium information such as a medium manufacturer name, a manufacturing factory name, a manufacturing line name, a manufacturing date and a manufacturing lot. The information thus written is usually read by a writer or reader. As a method of reading, light irradiation may be performed and a difference in the amount of reflected or transmitted light may be detected. In the case of mechanical reading, it is preferable that the above-mentioned information is replaced with a numeral and a bar code is recorded as a recording character. This information recording is usually made in a non-information area on the inner circumference of the disc.

In the present invention, when writing information such as a bar code on the reflective layer, air is blown from the outer circumference of the disk to the inner circumference of the laser irradiation portion. At that time, it is preferable that the linear velocity of the ventilation be increased to some extent, and more preferably 1 m /
It is more than sec. If the speed is too low, dust generated during laser irradiation will remain in the irradiated area, which not only makes reading with barcodes incomplete, but also spreads dust to the recording area when forming the protective layer by spin coating. However, the coating film becomes defective, resulting in poor appearance and poor environmental resistance.

The ventilation method may be either air supply for feeding gas or suction by a vacuum pump or the like, and both can be used. It is more preferable that the gas to be blown contains a small amount of an inert gas such as nitrogen, argon or helium. Moreover, you may use together with the static elimination blow of air supply gas.

A resin is usually used for the protective layer. A thermosetting resin is preferable from the viewpoint of protection effect, and an ultraviolet curing resin is particularly preferable from the viewpoint of productivity. The thickness of the protective layer is 1 to 15 μm
The degree is desirable. Further, it is preferable that the protective layer is formed beyond the recording layer and the reflective layer. Examples of the method for forming the protective layer include spin coating, screen printing, dipping, and spraying. Further, in the optical recording medium of the present invention, a label or the like can be printed on the protective layer and the protective layer.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited thereto. Example 1 An injection-molded polycarbonate resin substrate having a spiral groove (depth 140 nm, width 0.5 μm, pitch 1.6 μm) having a thickness of 1.2 mm and a diameter of 120 mm has Pd-tetra- (t at the center of the grooved surface. After adding a 3.5 wt% octane solution of a brominated (butylcyclohexyloxy) phthalocyanine (average of 3.0 molecules / molecule) octane solution, the resin substrate was rotated at a speed of 1500 rpm for 10 seconds. Further 3000 rpm
After rotating for 20 seconds, the resin substrate with this recording film formed
After drying in an atmosphere of 40 ° C. for 10 minutes, a recording layer consisting essentially of the phthalocyanine dye was formed on the resin substrate. A gold thin film having a thickness of 80 nm was formed as a reflective layer on the recording layer by sputtering.

At the innermost peripheral portion of the medium thus manufactured,
Manufacturing lot by bar code using YAG laser marker (LAY-724CK-2AB type, Toshiba Corporation, LAY-724CK-2AB type) with second harmonic oscillation unit under the conditions of current 13A output, speed 200mm / sec, Q switch frequency 45KHz. And the serial number was stamped. At that time, air containing 1% of argon gas was ventilated from the outer circumference of the disk toward the inner circumference at a linear velocity of 5 m / sec.

Further, on this reflective layer, DiCure S
D-17 (ultraviolet curing resin manufactured by Dainippon Ink and Chemicals, Inc.) was spin-coated and then irradiated with 2000 mj of ultraviolet rays to be cured to form a 6 μm protective layer. When the vicinity of the bar code written on the medium thus manufactured was observed with a microscope, the shape of the written portion was good, no dust was observed, and the reading by the bar code reader was good. In addition, the accelerated environmental test (5
00 Hr), the initial characteristics were the same and the results were good.

Example 2 When the same operation as in Example 1 was carried out except that the linear velocity of the blown gas was set to 1.2 m / sec, a small amount of dust was observed at the edge of the bar code under microscope observation. Reading with a barcode reader was good, and environmental resistance was also good.

Comparative Example 1 Pd-tetra was formed in the center of the grooved surface of an injection-molded polycarbonate resin substrate having a spiral groove (depth 140 nm, width 0.5 μm, pitch 1.6 μm) having a thickness of 1.2 mm and a diameter of 120 mm. After adding a 3.5 wt% octane solution of a brominated dye (average of 3.0 / one molecule) of-(t-butylcyclohexyloxy) phthalocyanine, the resin substrate was rotated at a speed of 1500 rpm for 10 seconds. . Further 3000r
After rotating at pm for 20 seconds, the resin substrate on which this recording film was formed was dried in an atmosphere at 40 ° C. for 10 minutes to form a recording layer consisting essentially of the phthalocyanine dye on the resin substrate.

A thickness of 80 nm is formed on the recording layer as a reflective layer.
Was deposited by sputtering. Furthermore, after spin coating Dicure SD-17 (UV curable resin of Dainippon Ink and Chemicals, Inc.) on this reflective layer, it is irradiated with 2000 mj of UV to cure it and form a protective layer of 6 μm. did.

At the innermost peripheral portion of the medium thus manufactured,
YA having second harmonic oscillation unit from above protective layer
G laser marker (TOSHIBA CORPORATION, LAY-724CK-2AB
Type), current 13A output, speed 200mm / sec,
The production lot and production number were stamped with a bar code under the condition of Q-switch frequency of 45 KHz.

When the vicinity of the bar code written on the medium thus manufactured was observed with a microscope, the shape of the writing portion was good, no dust was observed, and the reading by the bar code reader was good. When an accelerated environmental test (500 Hr) under 80 ° C./85% environment was performed, peeling was observed at the edge of the bar code, and deterioration of recording characteristics in the innermost peripheral area was observed.

Comparative Example 2 When the same operation as in Example 1 was carried out except that ventilation was not performed at the time of marking with a laser marker, a large amount of dust was observed in the bar code portion with a microscope, and it was observed in the recording area. It also reached.

[0028]

As is apparent from the examples, the present invention provides a single-plate write-once recordable optical recording medium comprising a resin substrate on which a dye-containing recording layer, a reflective layer and a protective layer are sequentially laminated. After forming the substrate, the recording layer, and the reflective layer, preferably, the reflective layer is removed under appropriate ventilation conditions to write readable information by reflection or transmission of light, and a protective layer is further formed thereon. By forming a medium by forming a film, dust generated during writing can be easily removed,
In addition, it is possible to provide a recording medium having good environment resistance characteristics.

Claims (8)

[Claims] 1. A recording layer containing a dye and a reflective layer are sequentially laminated on a transparent resin substrate, and at least a part of the reflective layer is removed from the reflective layer to reflect or transmit light. After writing the information that can be read by
An optical recording medium further comprising a protective layer. 2. The optical recording medium according to claim 1, wherein the information is written by a bar code. 3. Reflection or transmission of light by sequentially stacking a recording layer containing a dye and a reflective layer on a transparent resin substrate and removing at least a part of the reflective layer from the laminated reflective layer. A method for manufacturing an optical recording medium in which a protective layer is further laminated after writing readable information by. 4. The method for manufacturing an optical recording medium according to claim 2, wherein the information is written by a bar code. 5. The method for producing an optical recording medium according to claim 3, wherein information readable by light reflection or transmission is engraved by a laser in the leeward direction. 6. The method for manufacturing an optical recording medium according to claim 5, wherein when the information readable by light reflection or transmission is engraved by a laser, air is blown from the outer circumference of the disk to the inner circumference of the laser irradiation portion. 7. The method for producing an optical recording medium according to claim 5, wherein the linear velocity of ventilation is 1 m / sec or more. 8. The method of manufacturing an optical recording medium according to claim 5, wherein the gas to be blown contains an inert gas.