JPH053396B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an optical information recording medium that has a recording layer on a substrate and records and reproduces information using a high-density energy beam.

Recently, in optical information recording media that use a high-density energy beam such as a laser beam that can perform short-time exposure with high illuminance as a means of recording and reproducing information, it has become possible to directly reproduce information without post-processing immediately after recording. "DRAW" (Direct Read
2. Description of the Related Art Recording media having a (after write) characteristic have been used as memory media for video information such as document files and image files.

The recording layer of such a recording medium has conventionally been composed of a thin film made of a semimetal such as tellurium, bismuth, selenium or an oxide thereof, or a chalcogen compound such as selenium-tellurium-arsenic or tellurium-arsenic. However, such a material for the recording layer is toxic and unfavorable in terms of manufacturing. Furthermore, when used in general homes and offices, there is a risk of causing pollution problems. Furthermore, it has the disadvantage that the error rate during reproduction of recorded information increases due to oxidative deterioration of the compound contained in the recording layer.

In order to solve the above-mentioned drawbacks, the present inventors have developed an optical information system in which a physical development nucleus layer is provided on a transparent substrate, and a layer containing a metal compound that can be removed after physical development is laminated adjacently thereon. The recording medium was proposed in the specification of Japanese Patent Application No. 57-43305.

However, in a recording medium in which a removable metal compound layer is provided on such a physical development nucleus layer,
Physical development nuclei distributed throughout the physical development nucleus layer are developed from the surface, so in many cases, the reflectance for incident light from the substrate side is lower than the reflectance on the reflection side, and this is due to uneven concentration of metal particles. It has been found that there is a drawback that reflection noise is likely to occur.

However, on the other hand, if the amount of physical development nuclei is increased in order to obtain uniform reflectance without such uneven concentration of metal particles, the recording layer becomes electrically conductive. Japanese Unexamined Patent Publication 1973-
As described in Publication No. 108995, etc., it was found that the sensitivity decreased.

The present invention has been made based on the above-mentioned circumstances, and its first object is to provide a method for manufacturing an optical information recording medium that produces a good reproduced signal with less noise. There is a particular thing.

A second object of the present invention is to provide a method by which an optical information recording medium with high sensitivity can be manufactured.

The above object of the present invention has a recording layer on a substrate,
In a method for manufacturing an optical information recording medium that records and reproduces information using a high-density energy beam, island-shaped physical development nuclei are formed on a substrate, a polymer compound layer is formed on this, and this state is This is achieved by a method for producing an optical information recording medium, characterized in that metal atoms are attached to the physical development nuclei by physical development to form metal fine particles, and these are used as a reflective recording layer. .

In the present invention, the reflective recording layer is formed by physical development using physical development nuclei formed in the form of islands on the substrate, so that the smoothness of the substrate surface is reflected and the density unevenness of metal fine particles is reduced. Therefore, the noise with respect to the incident light from the substrate side is small, and as a result, the reflectance from the substrate side is high and uniform, and the S/N ratio of the reproduced signal is high. Furthermore, since the recording layer has non-contact between the fine metal particles and is practically non-conductive, this optical information recording medium has high sensitivity. Here, the surface resistance of the physical development nuclei formed in an island shape is 1 MΩ or more per unit area of 1 cm square, and the surface resistance of the recording layer after development is per unit area of 1 cm square.
Preferably it is 1KΩ.

In addition, if a polymer compound layer is provided on a substrate on which physical development nuclei are formed in an island shape, by controlling the degree of physical development using physical development nuclei as nuclei, it is possible to achieve a desired particle size in the polymer compound layer. It is possible to distribute the fine particles at any density, and therefore it is possible to obtain an optical information recording medium having any reflectance and absorption at any wavelength. This is because the polymer compound layer suppresses the diffusion of metal ions, and the speed of physical development is controlled by the developer temperature, pH, and
It is presumed that this is because the concentration can be easily lowered to a controllable range.

Next, the present invention will be explained in detail based on the drawings.

FIG. 1 is a sectional view showing a state in which physical development nuclei 2 are formed in an island shape on a substrate 1. As shown in FIG. The material of the substrate 1 may be any material as long as it is substantially transparent to high-density energy beams such as laser light, and specific examples thereof include cellulose triacetate, polyethylene terephthalate, polymethyl methacrylate, polycarbonate, and ceramic. ,
Examples include polyimide resin, glass, and metal. This substrate may be subjected to a subbing treatment, and in this case, a silane coupling agent, a titanium coupling agent, etc. can be used as the subbing treatment agent, and in particular, as described in US Pat. No. 3,661,584, The silane coupling agents described are preferred.
Furthermore, surface treatments such as corona discharge treatment, plasma discharge treatment, and ion bombardment treatment may be performed on the substrate to improve adhesion. Furthermore, guide grooves (fine relief shapes) can be formed on the substrate 1 for accurately setting recording and reproducing positions.

The physical development nucleus 2 is formed by forming a metal, a metalloid, or an oxide or sulfide thereof on a substrate in an island shape by a method such as a vapor deposition method, a sputtering method, a chemical vapor deposition method, or a chemical treatment of the substrate. It is preferable that the physical development nuclei are formed so as to be discontinuously adhered to each other, and that the surface resistance thereof is 1 MΩ or more per arbitrary 1 cm square unit area.
The film thickness of this physical development nucleus depends on the type of material, but is usually 100 Å or less.

As the vapor deposition method, in addition to the usual resistance heating method,
Electron beam evaporation, ion beam evaporation, ion plating, cluster ion beam evaporation, reactive evaporation, flash evaporation, laser evaporation, and the like can be used.

As the sputtering method, a high frequency sputtering method, a direct current sputtering method, a reactive sputtering method, a magnetron sputtering method, etc. can be used.

Chemical vapor deposition methods include reduced pressure vapor deposition method,
Plasma vapor deposition methods such as hydrogen reduction method, thermal decomposition method, glow discharge decomposition method, MOCVD (metal-organic
A chemical vapor deposition method or the like can be used.

Chemical treatment methods for substrates include, for example, PdCl ₂ -SnCl ₂ system and hydroxide colloids (Cu, Ni, Co) described in "Metal Surface Treatment Technology" Vol. 33, No. 11, 1982, pages 556 to 561. Examples include electroless plating methods using activators such as activators such as Sn-Cu, Al-orthophosphate, and the like.

Materials for the physical development nuclei used in the present invention include, for example, heavy metal sulfides (e.g., zinc, chromium, potassium, iron, cadmium, cobalt, nickel, lead, antimony, bismuth, silver, cerium, arsenic). , steel and rhodium sulfides) are preferred; other metal selenides (eg lead, zinc, antimony and nickel selenides) are preferred.

Another group of useful physical development nucleus materials include:
Mention may be made of noble metals such as silver, gold, platinum, palladium and mercury. Salts of such metals, preferably simple inorganic and easily reducible salts such as silver nitrate, gold chloride and gold nitrate, are also useful as materials for physical development nuclei.

Another group of useful physical development nucleus materials includes thio compounds such as silver thioxate and its lead and nickel complex salts, thioacetamide, and the like.

Among the above materials, preferred materials for the physical development nuclei include heavy metal sulfides, such as zinc, cadmium, silver,
These are sulfides such as lead, and metals such as silver, gold, palladium, and copper.

FIG. 2 shows a precursor A of an optical information recording medium obtained according to the present invention. In the figure, 3 is a polymer compound layer, which is preferably formed of a thin film mainly composed of an organic polymer compound, that is, a binder. Specifically, natural organic polymer compounds such as gelatin, casein, and cellulose, and polyacrylamide,
Water-soluble resins such as polyacrylic acid and ionic resins are preferred as materials for the polymer compound layer.

In addition, the materials for the polymer compound layer include styrene resin, acrylic resin, vinyl chloride monovinyl acetate copolymer, vinyl acetate-methyl methacrylate copolymer, styrene-butadiene copolymer, vinyltoluene-butadiene copolymer, and polycarbonate resin. , polyurethane resins, phenolic resins, epoxy resins, melamine resins or furan resins can also be used. These can also be used in combination of two or more types as necessary.

The polymer compound layer can be easily formed by applying a solution of these materials. As a solvent for preparing the solution, a solvent that can disperse or dissolve an organic substance, such as water or a low-boiling organic solvent (ethanol, ethyl acetate, etc.), can be used. Any coating method can be used such as blade coating, air knife coating, bar coating, curtain coating, spinner coating, or roll coating, and the dry film thickness is usually 0.05 to 20μ.
m, preferably 0.01 to 0.1 μm.

Further, the polymer compound layer may be a layer containing an organic substance in which colloidal metal atoms are dispersed.

The polymer compound layer can also be formed by a method of forming a uniform thin film using a vapor phase growth method such as a chemical vapor deposition method. A polymer film of an organic compound may be formed and this may be used as a polymer compound layer.

The recording characteristics can be further improved by adding a dye or pigment that absorbs the wavelength of the recording high-density energy beam to the polymer compound layer. The dye used here is
Those that are difficult to deteriorate by high-density energy beams are preferred, such as azo-based, anthraquinone-based, indigoid-based, phthalocyanine-based, carbonium-based including triphenylmethane-based, quinoneimine-based, methine-based, quinoline-based, nitro-based, and nitroso-based. , benzoquinone-based dyes, etc. are used.
Cobalt-based, manganese-based,
Chromium-based, cadmium-based, and iron-based pigments, as well as pigments such as ultramarine blue and deep blue, can also be used.

4 is a metal compound-containing layer that supplies metal atoms to physical development nuclei through physical development. Materials for this metal compound include gold salts (e.g. sodium salts), copper salts (e.g. CuBr, CuCl ₂ , CuSCN), lead salts (e.g. PbO, PbCl ₂ , PbBr ₂ ), iron salts (e.g. oxalates, nitrates). ), iron complex salts (e.g. oxalate, malonate), silver salts (e.g. AgCl, AgBr,
AgI, AgNO ₂ , Ag ₂ SO ₄ , Ag ₂ S), cobalt salts (e.g. CoCl ₂ , CoSO ₄ ), nickel salts (e.g. Ni
(NO ₃ ) ₂ , NiCl ₂ ), others HgCl ₂ , BiCl ₂ , TeCl ₄ ,
InBr ₃ and the like can be mentioned, but in the present invention, silver salts, copper salts, nickel salts, and cobalt salts are particularly preferably used, and silver halides are most preferred. In this case, silver halide also has the advantage of being non-polluting.

The grain size of the silver halide is 0.01 to 1 μm, preferably 0.02 to 0.1 μm.

When using a silver halide emulsion as the metal compound, it is desirable to add an antifoggant, a coating aid, and a hardening agent, but it is not necessary to have sensitivity to visible light, so a sensitizing means is not necessarily required. There is no need to apply it. In addition, directly into the silver halide emulsion,
It is also possible to add a developing agent, such as hydroquinone or phenidone, and develop with only an alkaline solution containing a silver halide solvent to precipitate silver in a silver mirror shape.

The metal or metalloid supplied to the physical development nucleus by physical development is supplied from a metal compound-containing layer provided on the physical development nucleus or from a developer containing the metal compound. In this physical development process, metal is deposited on the island-shaped physical development nuclei 2 formed on the surface of the substrate 1 and grows in the direction opposite to the substrate to form metal fine particles. A reflective recording layer 5 (see FIG. 3) is formed.

The above-mentioned physical development is usually carried out by a known method using a physical developer, and any conventional developer can be used as the physical developer at this time.

That is, it is an alkaline solution or an acidic solution containing at least a developing agent, and any type of developer known in the art can be used.

For example, metol, hydroquinone, catechol, p-phenylenediamine, ascorbic acid,
A solution containing hydrazine and its derivatives, or hydrazine, its hydroxide, or its salt as a developing agent can be used.

In the present invention, when a metal is supplied from a metal compound-containing layer provided on a polymer compound layer on physical development nuclei, it is preferable to remove this layer after physical development. The layer is removed by, for example, peeling, dissolving, or the like. The above peeling operation is
The water washing step after physical development can be carried out by raising the temperature during water washing to a temperature at which the hydrophilic colloid dispersion medium of the metal compound-containing layer dissolves or becomes a sol. At this time, if the polymer compound layer is hardened with a hardening agent, the metal compound-containing layer can be effectively peeled off. As another method, the metal compound-containing layer can be preferably peeled off by immersing it in a concentrated strong electrolyte aqueous solution to cause membrane contraction, and then washing it with warm water. The strong electrolyte used in this case is preferably a salt of a strong acid and a strong base, such as sodium sulfate. Further, the same effect can be obtained even when the above-mentioned strong electrolyte is contained in a physical developer.

The liquid temperature during the above-mentioned hot water washing is, for example, 20 to 50°C when the hydrophilic colloid dispersion medium is gelatin, preferably around 40±5°C.

FIG. 3 shows a precursor A of the recording medium shown in FIG.
FIG. 2 is a cross-sectional view showing the structure of an optical information recording medium obtained by the present invention, in which the metal compound-containing layer 4 is removed after physical development. In FIG. 3, reference numeral 5 denotes a polymer compound layer (hereinafter referred to as "recording layer") coated on the physical development nuclei to which metal is supplied by physical development and the reflectivity is improved. In this layer, the particles remain non-contact even after physical development, so the electrical conductivity remains low, and therefore the thermal conductivity is very low, which is the high level required for bit formation. The advantage is that the intensity of the density energy beam can be small.

FIG. 4 is a cross-sectional view of an optical information recording medium obtained by the present invention in which pits are formed by irradiating a high-density energy beam from the direction of the substrate to melt or blow off the irradiated portion of the recording layer. shows. In this figure, 6 is an arrow indicating a high-density energy beam, and 7 is an arrow indicating a formed pit.

According to the present invention, it is possible to write by utilizing the reduced reflectivity of the pit 7 portion, and to read and reproduce information using a high-density energy beam that is weaker than the high-density energy beam.

Although known high-density energy beams for recording pit information can be used in the present invention, laser beams are preferred.
This laser can be used with continuous wave oscillation or pulse oscillation. Specifically, the Lewy laser (6943Å), argon ion laser (4880Å)
Å, 5145Å), glass laser (1.06μm), He-
Ne laser (6328Å), Krybton ion laser (6471Å), He-Cd laser (4416Å, 3250Å)
), dye laser, semiconductor laser, etc. can be used. Other high-density energy beams such as xenon lamps, mercury lamps, arc lamps, etc. can also be used.

The high-density energy beam used for recording and reproducing on the recording medium obtained by the present invention may be of the same type or different types, and is usually irradiated through a transparent substrate, but It is also possible to directly irradiate.

FIG. 5 shows a cross-sectional view of an optical information recording medium in which a photosensitive layer is used as the metal compound-containing layer of the present invention, and the surface of the layer is subjected to pattern exposure. In this figure, parts with the same symbols as in FIG. 2 indicate the same parts. 12 is a photosensitive metal compound-containing layer;
Reference numeral 8 indicates a pattern mask, and reference numeral 9 indicates a high-density energy beam suitable for exposing the photosensitive metal compound-containing layer. The above-mentioned silver halide is preferably used as the photosensitive metal compound in the illustrated example.

When using an information recording medium in which a photosensitive metal compound-containing layer is laminated on a polymer compound layer on physical development nuclei as shown in the illustrated example, physical development is performed by pattern exposure on the surface of the photosensitive layer. During development, the dissolution physical development action in the exposed area is suppressed, and as a result, a pattern in which the reflectance of the physical development nucleus layer changes in a pattern is formed.

FIG. 6 shows a pattern-like change in reflectance in the recording layer as described above with the metal compound-containing layer removed. That is, 10 indicates a weakly reflective part where the physical development effect is suppressed, and 11 indicates a highly reflective part.

As is clear from the above description, according to the recording medium obtained by the present invention, tracks or other necessary information can be photographically recorded in advance on the recording medium as necessary. Further, according to the recording medium obtained according to the present invention, it is possible to impart arbitrary reflectance and absorption coefficient to light of arbitrary wavelength by means such as exposure or development. This thing is
This is important because recording energy can be controlled arbitrarily, and it is also important because a good reproduction signal-to-noise ratio can be obtained.

EXAMPLES Hereinafter, the present invention will be specifically explained according to Examples, but the embodiments of the present invention are not limited thereby.

Example 1 A thin film of silver was vacuum-deposited to a thickness of about 30 Å in the form of an island on a substrate made of 1.2 mm thick glass with excellent smoothness to form physical development nuclei.
At this time, the transmitted density was close to zero, and the surface conductivity was not measured.

0.5 of a 1:4 mixture of gelatin and hydroxypropyl methylcellulose was applied onto this physical development nucleus.
% mixed aqueous solution was applied using a spinner and dried to form a polymer compound layer with a thickness of about 300 Å. On this polymer compound layer, a fine-grain silver iodobromide gelatin emulsion (added silver 3 mol %, average grain size 0.05 μm) was coated as a metal compound at a coating silver amount of 3 g/m ² to contain a metal compound. A layer was formed and a sample was obtained.

After developing this sample for 1 minute at a temperature of 30°C with a developer of the following composition without exposing it to light,
The metal compound-containing layer was peeled off by immersing it in a 20% aqueous solution of Na ₂ SO ₄ for 1 minute and washing with warm water at 37°C.

[Developer]

Phenidone 1.0g Anhydrous sodium sulfite 65.0g Hydroquinone 12.0g KOH 15.0g KBr 0.5g Sodium thiosulfate 5.0g Water was added to the above to make 1. The reflectance of the recording medium thus obtained through the substrate was 36 at 633 nm. % and the absorbance is 0.68
It was hot. Moreover, the resistance per unit area of 1 cm square of the surface was about 5 KΩ.

The recording medium sample obtained according to the present invention was irradiated with a He-Ne laser beam of 10mW output on the recording surface having a beam diameter of 1.4μm at a distance of 10m/
Writing and recording was carried out by scanning at a scanning speed of sec and applying a pulse signal of 200 nsec using an acousto-optic modulator to form pits. As a result, a recording surface with a remarkable difference in reflectivity was obtained, good signal contrast was obtained, and optical reading was easily possible. The writing threshold energy at this time was about 50 mJ/cm ² , and the recording/reproduction SN ratio was 50 decibels or more.

Example 2 On a substrate made of polymethyl methacrylate having a thickness of 1.2 mm and having excellent smoothness, gold was deposited in the form of islands by vacuum evaporation to form physical development nuclei. At this time, the transmitted density was close to zero, and the surface conductivity was not measured.

On this physical development nucleus, a 1:4 mixture of gelatin and hydroxypropyl methylcellulose was applied.
A 0.5% aqueous solution was applied using a spinner and dried to form a polymer compound layer with a thickness of about 300 Å. Fine particles are formed as metal compounds on this polymer compound layer.
A CuBr _0.97 I _0.03 emulsion was applied, and physical development was performed for 1 minute at a developing temperature of 25° C. using an aqueous solution (PH 11.5) containing triethylenetetraamine as a main component. At this time, the copper halide emulsion layer was dissolved and removed.

The reflector of the recording medium exhibiting a copper mirror thus obtained through the substrate was about 30% at 633 nm, and the resistance per unit area of 1 cm square of the surface was about 10 KΩ.

When recording was performed on the thus obtained recording medium in the same manner as in Example 1, the threshold energy for writing was approximately 50 mJ/cm ² .
The recording/reproduction signal-to-noise ratio was over 47 decibels.

Comparative Example 1 A comparative sample was obtained in the same manner as in Example 1, except that a thin film of silver with a thickness of about 150 Å was provided on the substrate by vacuum deposition to form physical development nuclei. The resistance per unit area of 1 cm square on the surface of this comparative sample was almost zero, indicating that the physical development nuclei were not island-like. The reflectance of the comparison sample obtained through the substrate was 65% at 633 nm,
The absorbance was 1.8. Moreover, the resistance per unit area of 1 cm square of the surface was almost zero.

When this comparative sample was subjected to recording in the same manner as in Example 1, no recording could be made at all. This is presumed to be because the recorded energy is lost due to heat conduction.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention.
The figure is an explanatory cross-sectional view showing a state in which physical development nuclei are formed on a substrate, FIG. 2 is an explanatory cross-sectional view showing the structure of a precursor of an optical information recording medium, and FIGS. 3 and 4 are optical FIGS. 5 and 6 are explanatory cross-sectional views showing the structure of a precursor of an optical information recording medium according to other embodiments, respectively. It is an explanatory sectional view showing the composition of DESCRIPTION OF SYMBOLS 1...Substrate, 2...Physical development nucleus, 3...High molecular compound layer, 4...Metal compound containing layer, 5...Recording layer, 6...High density energy beam, 7...Pits, 8... Pattern, 12...photosensitive metal compound-containing layer.

Claims (1)

[Claims] 1. A method for manufacturing an optical information recording medium that has a recording layer on a substrate and records and reproduces information using a high-density energy beam, comprising: forming island-shaped physical development nuclei on the substrate; form,
A polymer compound layer is formed on this, and in this state, metal atoms are attached to the physical development nuclei by physical development to form metal fine particles, and this is used as a reflective recording layer. A method for manufacturing an information recording medium.