JPH0460038B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an optical information recording medium on which information is recorded and reproduced by irradiation with a high-density energy beam such as a laser beam. In particular, the present invention relates to an optical information recording medium suitable for long-term storage of information. (Prior art) Information such as audio and video is optically recorded as changes in the shape, dimensions, optical reflectance, etc. of bits (concave parts) or blocks (convex parts), and is also optically extracted to record audio, video, etc. The recording layer of the optical information recording medium used in the method of converting into a video signal and playing it back is as follows.
Various compositions have been known, one of which is a thin film made of metalloids such as Te, Bi, Se, or their oxides, or chalcogen compounds such as Se-Te-As and Te-As. be. Microscopically, the thin film has a fine particle structure, and the error rate during reproduction of recorded information increases due to oxidative deterioration of the compounds contained in the recording layer, and the reliability of the safety of the compounds used increases. It has the disadvantage of being thin. In addition, there are recording layers for optical information recording media having a metal fine particle structure in which fine particles of a metal or its oxide are dispersed in a binder made of a polymer (Japanese Patent Application Laid-open Nos. 57-12425 and 57-24290).
No. 57-39989, No. 55-108995, No. 56-
No. 33995, No. 56-49296, No. 56-49297, No. 56
The present inventors also proposed a recording medium suitable for optical recording and reproduction through a transparent support in Japanese Patent Application No. 57-43305. However, when the recording layer for an optical information recording medium having a metal fine particle structure is stored for a long period of time, from several years to ten years, or when stored under conditions such as high temperature or high humidity, the metal fine particles may be oxidized or hydrated. It is known that oxidation causes changes in physical properties, particularly optical properties such as reflectance and absorption. In addition to optical properties, changes in thermal conductivity, physical strength, etc. may also occur, resulting in a decrease in laser recording sensitivity, a decrease in the signal-to-noise ratio of the reproduced signal, and an increase in the bit error rate. This is a serious drawback. (Object of the Invention) Therefore, the object of the present invention is to provide an optical recording medium in which a recording layer provided on a support is used as a layer for recording and reproducing information using a high-density energy beam such as a laser beam. The object of the present invention is to provide an optical information recording medium that can improve the drawbacks, can be stored for a long period of time, and has good recording and reproducing characteristics. Another object of the present invention is to provide a recording medium having a recording layer that has a high absorption rate and a high reflection rate for recording and reproducing beams through a support. Another object of the present invention is to provide an optical recording medium having a recording layer with excellent uniformity and stability. (Structure of the Invention) The present invention achieves the above object in an optical information recording medium that records and reproduces information by irradiating a reflective recording layer provided on a support with a high-density energy beam. The layer contains reflective metal particles, and the surface of the metal particles is
It is characterized in that it is coated with a water-insoluble metal complex whose solubility in water at 25°C is 1 g/or less. In the present invention, a compound (ligand) having the ability to coordinate with a metal ion having a fine particle structure is used as a compound that generates a water-insoluble metal complex. In particular, (1) the total stability constant (K) of the complex with the metal is large, and (2) the metal complex constitutes an intramolecular complex salt that is electrically neutral and satisfies the number of coordination sites of the metal. (3) Ligands having a hydrophobic group, such as an aryl group, a heterocyclic group, or an alkyl group in the molecule at a site that does not cause steric hindrance to the complex structure, are preferred. Here, if the total stability constant indicating the stability of the complex is K, M is the metal, and L is the ligand, then K is the equilibrium constant of the complexation equilibrium equation shown below. ^{ML _} _{_} ^{_ _} _{_} ^{_ _ _ _ _} It is preferable that the value is 5.0 or more. If it is less than 5.0, the metal ions generated by the dissociation of the generated metal complex will further participate in the oxidation reaction, causing deterioration of the recording layer, which is not practical. Water insolubility in the present invention means that the complex formed on the surface of the metal fine particles in the recording layer has hydrophobicity or water insolubility, so that the complex coating that prevents oxidative deterioration inside the metal fine particles is retained against water. Generally speaking, the solubility in water at 25℃ is 1.
g/ or less. In the present invention, compounds that form metal complexes suitable for the present invention include oxygen (O), nitrogen, which has a strong coordination force as a donor atom.
(N), sulfur (S) as a coordination group, and has stability due to resonance effect or chelation effect, that is, the formation of chelate rings, especially 5- to 6-membered rings, stability due to the number of chelate rings, and stability due to the number of chelate rings. The ionic radius of the metal ion to be
It has at least one effect such as stability of the resulting complex without steric hindrance due to the directionality of the coordination bond,
A group of ligands that is electrically neutral as a requirement for water insolubility, satisfies the number of coordination sites of metal ions, and forms a complex without the risk of coordination of coordinating water over time, From among these, a suitable ligand is selected for each metal ion. That is, in the present invention, the coordination group generally has the O, N and S atoms as donor atoms, and the O, N
and S, there are two or more donor atoms at a convenient distance to form a chelate ring by allowing overlap, and a polydentate ligand having a hydrophobic group at a position that does not cause steric hindrance. In particular, bidentate ligands are particularly useful since the number of coordination sites of metal ions is generally an even number. However, it is acceptable to use odd-dentate ligands if necessary. The combination that takes two from O, N and S that allow duplication is obviously O-O, O-N, O-S, N
-N, N-S and SS. Specifically, the ligands preferably used in the present invention are N-N type, such as α-oxime,
Bipyridine, phenylenediamine, N-O type examples include oxine, oxime, quinaldic acid,
Quinoline-8-carboxylic acid, nitrosonaphthol, O-O type examples include clopene, salicylic acid, hydroxynaphthaldehyde, N-S type examples include thioxin, thiourea, S-S type examples include mercaptobenzothiazole, bismuthiode, etc. Examples of the SO type include 3-mercapto-4-hydroxytoluene. As a method for incorporating the compound having coordination ability of the present invention into the recording layer, a medium having the recording layer is immersed in a solution of the compound at a concentration of 10 ^-4 M to 10 ^-1 M, and then, if necessary, Rinse liquid (or washing liquid)
There is a method of immersing it in water. In addition, when the metal fine particles are obtained by coating, they can also be obtained by adding the above compound into the coating solution, or by co-evaporation of the above compound. On the other hand, metal ions as electron pair acceptors also affect the stability of metal complexes. It is known that transition metals have a strong tendency to receive electron pairs from donor atoms to form stable coordination bonds. , groups a to b, groups b 3 to 6 periods, group b 4 to 6 periods, group b 4 to 6 periods generally form chelates, and group a 2 to 7 periods, group a 4 periods. It is known that elements arranged in ~7 periods have some difficulty in chelate formation. In the above-mentioned chelate-forming metal elements, there is an electrostatic effect on complex formation due to the combination of ionic radius and charge, and repulsion against specific ligands due to the direction of coordinate bonding due to various bond types such as linear, tetrahedral, and octahedral types. , and H ⁺ according to Lewis's definition,
Coordination by hard acids such as Be ²⁺ , Al ³⁺ , soft acids such as Ag ⁺ , Hg ²⁺ , Tl ³⁺ , or intermediate acids such as Fe ²⁺ , Ni ²⁺ , Zn ²⁺ There are differences in coordination stability depending on the type of child. In the present invention, the metal elements to be used in the present invention are selected from among the above-mentioned metal elements in terms of recording suitability, coordination stability, cost, and practicality such as resource amount. Preferably used metals with a fine particle structure contained in the recording layer of the present invention include Be, Mg, Sc,
Y, Sm, Th, Ti, Zr, Hf, V, Nb, Ta, Cr,
Mo, W, Mn, Re, Fe, Co, Ni, Ru, Rh,
Pd, Ir, Pt, Ag, Au, Zn, Cd, Hg, Al, Ga,
In, Tl, Si, Ge, Sn, Pb, As, Sb, Bi, Se,
Te may be used alone or in combination or as an alloy of two or more. Methods for providing the recording layer of the present invention include vapor deposition,
Sputtering, ion plating, CVD
Various methods can be used, such as electroplating, electroless plating, coating of the metal dispersion, and photographic development of the dispersed layer of metal compound particles. By the above method, the recording layer can be provided as a laminated layer or a mixed layer of the above metal and the compound described below. The thickness of these recording layers varies depending on the material, but is generally preferably 50 to 5000 Å. Table 1 shows representative examples of preferred combinations of the compound having coordination ability of the present invention and metal fine particles.

【table】

[Table] Of course, the present invention is not limited to the above representative examples. The support preferably used in the present invention is
Examples include cellulose triacetate, polyethylene terephthalate, polymethyl methacrylate, polycarbonate, ceramics, polyimide resins, glass, metals, etc. These supports do not necessarily have to be subbed-treated; Preferably. As the subbing treatment agent in this case, for example, a silane coupling agent, a silicate coupling agent, a titanium coupling agent, etc. can be used, and the silane coupling agent described in US Pat. No. 3,661,584 is particularly preferred. Further, surface treatments such as corona discharge treatment, plasma discharge treatment, and ion bombardment may be performed on the support to improve adhesion. Further, a support having guide grooves (fine relief shapes) for accurately setting recording and reproducing positions can also be used. Furthermore, an undercoat layer may be provided to improve the surface properties of the support and the adhesion between the support and the recording layer. In the recording layer of the present invention, as a binder for the metal fine particles, inorganic compounds such as metal oxides, metal halides such as metal fluorides, metal nitrides, metal sulfides, dyes, pigments, natural polymers, synthetic polymers, etc. Organic compounds such as can be used. The dyes that can be used in the present invention are preferably ones that have excellent thermal stability and are resistant to deterioration, such as azo, anthraquinone, indigoid, phthalocyanine, carbonium-based pigments including triphenylmethane, quinoneimine-based, methine-based, quinoline-based, There are nitro series, nitroso series, benzoquinone series, etc.
Further, as inorganic coloring pigments, cobalt-based, manganese-based, chromium-based, cadmium-based, iron-based pigments, ultramarine blue, navy blue, etc. are also used. As the organic polymer used in the present invention, natural organic polymers such as gelatin, casein, and cellulose, and water-soluble resins and ionic resins such as polyacrylamide and polyacrylic acid are preferable.
High purity gelatin for the photographic industry is most preferred. In addition, styrene resin, acrylic resin, vinyl chloride
Vinyl acetate copolymer, vinyl acetate-methyl methacrylate copolymer, styrene-butadiene copolymer, vinyltoluene-butadiene copolymer, polycarbonate resin, polyurethane resin, phenol resin, epoxy resin, polyurethane resin, phenol resin, epoxy resin , melamine resin, furan resin, or the like can be used alone or in combination of two or more. If these organic compounds have excellent thermal stability, they may be co-deposited with the metal, or in other cases, after dissolving, mixing, or dispersing the metal in a solution or dispersion of the organic substance, It can be included as a binder in the recording layer by a coating method. As the coating method, wire bar coating, spinner coating, dip coating, air knife coating, bead coating, curtain coating, etc. can be used. The metal oxides used in the present invention include Al ₂ O ₃ , InO, In ₂ O, In ₂ O ₃ , SiO, SiO ₂ ,
GeO, SnO, PbO, TiO ₂ , ZrO ₂ , V ₂ O ₅ , MoO,
WO ₃ etc. are used, and metal fluorides include:
TiF ₄ , VF ₅ , MoF ₄ , RhF ₃ , MgF ₂ , CaF _{2 ,} etc. are used, and metal nitrides include Mg ₃ N ₂ , Ca ₃ N ₂ ,
Sr ₃ N ₂ etc. are used, and the metal sulfides include CrS,
MoS ₂ , ZnS, In ₂ S ₃ , GeS, SnS, PbS, As ₂ S ₃ ,
Sb ₂ S ₃ etc. are used. These inorganic compounds can be incorporated into the recording layer as a binder by various methods such as co-evaporation with the metal, multi-element sputtering, and ion plating. In addition to the recording layer containing fine metal particles and a compound that forms a water-insoluble metal complex, the optical information recording medium of the present invention may optionally include a reflective layer made of a metal, or a recording layer and a reflective layer. It may also have a thermal insulating layer provided between it. Furthermore, it is obvious that providing a protective layer on the above-mentioned layer is an effective method for improving the durability, mechanical strength, and stability over time of a recording material.
The protective layer may be made of either an inorganic or organic material, but it must be transparent to the high energy density light beam used, have high mechanical strength, be difficult to react with the recording layer, and be coated. It is required to have good properties and be easy to manufacture. The protective layer used in the present invention may be made of either an inorganic substance or an organic substance, but examples of the inorganic protective layer include Al ₂ O ₃ , SiO ₂ , SiO, MgO,
Transparent substances such as ZnO, TiO ₂ , ZrO ₂ , MgF ₂ and CuF ₂ are desirable. These are formed by reactive deposition such as vacuum deposition, sputtering, and ion plating. It is also an excellent method to use organic substances as a protective layer. Various resins can be used as the protective layer, including styrene resins such as polystyrene, styrene-maleic anhydride resin, vinyl acetate resins such as polyvinyl acetate, polyvinyl alcohol, butyral, and polyvinyl formal, and polyvinyl acetate resins such as polyvinyl acetate, polyvinyl alcohol, butyral, and polyvinyl formal. Methacrylate ester resins such as isobutyl methacrylate and polymethyl methacrylate, amide resins such as polydiacetone acrylamide and polyacrylamide, ethyl cellulose, cellulose acetate lactate,
It is selected from cellulose resins such as cellulose nitrate and diacetyl cellulose, polyvinyl chloride, polyhalogenated olefins such as chlorinated polyethylene, phenolic resins, soluble polyesters, soluble nylons, gelatin, etc., and copolymers thereof. These can be used alone or in combination of two or more. Further, these resins can be dissolved in various solvents and applied by known coating methods. Further, when a transparent substrate is used as a support, the support itself can be used as a protective layer by using an air sandwich structure or the like. As the high-density energy beam that can be used to record information in the present invention, for example, a xenon lamp, a mercury lamp, an arc lamp, a laser, etc. can be used, and among these, a laser is preferable because it can perform high-density recording. . As the laser light, either continuous wave oscillation or pulse oscillation can be used. Lasers that can be used include ruby laser (wavelength: 6943 Å), argon ion laser (wavelength: 4880 Å, 5145 Å), glass laser (wavelength: 1.06 μm), helium-neon laser (wavelength: 6328 Å), and krypton ion laser (wavelength: 6471 Å).
), helium-cadmium laser (wavelength 4416Å,
3250 Å), dye lasers, semiconductor lasers, etc. The high-density energy beam for recording on the optical information recording medium of the present invention and the high-density energy beam for reproducing may be of the same type or different types, and are preferably irradiated through a transparent support. However, it is also possible to directly irradiate the recording layer surface side opposite to the transparent support. (Example) Examples of the present invention will be described below, but the present invention is not limited thereto. Example 1 Te on polymethyl methacrylate with a thickness of 1.2 mm
was deposited to a film thickness of 800 Å, immersed in a 0.001M methanol solution of 3-phenyl-5-mercapto-1,3,4-thiodiazole-2-thione, dried in vacuum, and then deposited in an air sandwich structure. Enclosed. Reflectance at 830nm was 45% at 50℃
After one month of forced deterioration test at 80RH%, it changed to 42%. Comparative Example 1 In the sample in which the immersion treatment was omitted in Example 1, the reflectance decreased to 12% in the same forced deterioration test, and it could not be put to practical use. Example 2 An aqueous gelatin dispersion solution of colloidal silver particles serving as physical development nuclei was obtained by reducing silver nitrate with dextrin, the weight ratio of silver to gelatin was 32%, and the particle size of the colloidal particles was approximately
It was 150Å. This solution was applied to a smooth glass plate that had been undercoated with a silane coupling agent using a wire parser so that the film thickness after drying was 300 Å. A physical development nucleus layer was provided. On this physical development nucleus layer, a fine grain silver iodobromide gelatin emulsion (silver iodide 3 mol%, average grain size 0.05μ) as a metal compound was coated at a coated silver amount of 3 g/m ² , and a sample was prepared. 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 emulsion 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 Add water to make 1. As a result, the reflectance of the recording medium through the glass substrate was 46% at 830 nm. The sample was converted into 1-phenyl-5-mercapto-
It was immersed in a 0.002M aqueous solution of 1H-tetrazole for 30 seconds, washed with water, and dried. At this time, there is no change in reflectance. A forced deterioration test was conducted for one month at 50°C and 80RH%, but no decrease in reflectance was observed. Comparative Example 2 When a forced deterioration test was conducted in Example 2 by omitting the immersion treatment, the reflectance decreased to 41% and deteriorated. (Effects of the Invention) The stability over time of the recording medium was significantly improved compared to the conventional one. In addition, material constraints in the production of optical information recording media have been significantly reduced, and the difficulty in maintaining the quality of the media has also been reduced.

Claims (1)

[Claims] 1. An optical information recording medium in which information is recorded and reproduced by irradiating a reflective recording layer provided on a support with a high-density energy beam, wherein the reflective recording layer contains reflective metal fine particles. , and the surface of the metal fine particles is coated with a water-insoluble metal complex having a solubility in water at 25° C. of 1 g/or less.