JP2000322764A - Optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the progress of corrosion of a metallic film by allowing a material having electron accepting property or electron donative property forming a salt on the interface between the metallic layer and a recording layer when the material is oxidized or reduced by irradiation with light to exist near the metallic layer. SOLUTION: An information recording part 3 is formed with a material having the property of an acid radical or a base in correspondence with the redox reaction of a metallic film and it is formed by filling a heat-mode recording material containing a material which absorbs light energy and converts it to heat energy or such an ionic dye material into a preformat pattern 2. When light is radiated, the redox reaction of the metallic film takes place and the film reacts with the material having electron accepting property or electron donative property disposed near the metallic film so as to assist a flow of electrons and forms a microscopically observable salt having <=10 μm, preferably <=5 μm particle diameter. This reaction proceeds slowly unlike sudden corrosion of the reflecting film caused, e.g. when water sticks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an optical information recording medium,
In particular, the present invention relates to a CD-R, a DVD-R and the like using a silver reflection film.

[0002]

2. Description of the Related Art Conventionally, a gold reflective film has been used as a metal material for an optical information recording medium such as a CD-R. However, it is required that the recording medium be inexpensive, and a metal film containing silver as a main component is required. Came to be used. However, the stability is poor because silver is the main component, especially when irradiated with light.
There is a problem that the oxidation-reduction reaction of silver proceeds rapidly, and the metal film is corroded to generate a large defect.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has as its object to provide an optical information recording medium capable of suppressing the progress of corrosion of the metal film.

[0004]

According to the present invention, first, in an optical information recording medium having a recording layer and a metal layer provided directly or via an underlayer on a light-transmitting substrate, A material having an electron accepting or electron donating property that is oxidized or reduced by light irradiation to generate a salt at the interface between the metal layer and the recording layer in the vicinity of the optical information recording medium. Is done.

Second, in the optical information recording medium described in the first aspect, the material having the electron accepting or electron donating property is present in the recording layer or an intermediate layer provided between the recording layer and the metal layer. An optical information recording medium is provided.

Thirdly, there is provided an optical information recording medium according to the first or second aspect, wherein the metal layer contains silver as a main component.

Fourthly, in the optical information recording medium described in the first, second or third aspect, the salt is a normal salt, an acidic salt,
An optical information recording medium characterized by being a basic salt or an oxide salt is provided.

Fifthly, there is provided an optical information recording medium according to the first, second, third or fourth aspect, wherein the salt has a particle diameter of 10 μm or less. You.

Hereinafter, the present invention will be described in detail. As described above, the present invention relates to an optical information recording medium in which a recording layer and a metal layer are provided directly or through an underlayer on a light-transmitting substrate, and the vicinity of the metal layer is oxidized or reduced by light irradiation. A material having an electron-accepting or electron-donating property to form a salt at the interface between the metal layer and the recording layer. According to this configuration, since a material having an electron accepting property or an electron donating property exists near the metal film, an oxidation or reduction reaction occurs by light irradiation, and a salt is generated at an interface between the metal film and the recording layer. The progress of corrosion of the metal film is suppressed by the presence of the salt, and large defects larger than 10 μm (a part where the corrosion of silver is advanced and the reflectance is reduced over a wide range such as formation of silver chloride) can be reduced. it can.

When the material having the electron accepting property or the electron donating property is present in the recording layer or an intermediate layer provided between the recording layer and the metal layer, the salt can be favorably formed. . An optical information recording medium using silver as the metal film has excellent adaptability. Further, since the generated salt is a normal salt, an acidic salt, a basic salt or an oxide salt, the progress of corrosion is suppressed, and large defects larger than 10 μm can be reduced. Furthermore, when the particle diameter of the salt is 10 μm or less, the progress of corrosion is suppressed, and large defects larger than 10 μm can be reduced.

Hereinafter, the present invention will be described in detail with reference to examples. In each example, the embodiment will be described first, and then a more specific experimental example will be described. [First Embodiment] An optical information recording medium according to a first embodiment will be described with reference to FIGS. As is apparent from both figures, the optical information recording medium of this example is formed by filling a transparent substrate 1 having a preformat pattern 2 formed on one side thereof in a fine uneven shape, and filling the inside of the preformat pattern 2. An information recording unit 3, a metal layer 4 applied on the information recording unit 3, a protective layer 5 coated so as to cover the metal layer 4, and a thin layer 8 laminated on the protective layer 5. ing.

As the transparent substrate 1, for example, a transparent resin material such as polycarbonate, polymethyl methacrylate, polymethyl pentene, epoxy or the like is formed into a desired shape, and a desired preformat pattern is transferred to one surface of the transparent resin material. Any transparent substrate belonging to the public domain, such as a transparent resin layer having a desired preformat pattern transferred onto one surface of a transparent ceramic plate such as glass formed into a shape, can be used. A transparent substrate 1 constituting a disc-shaped optical information recording medium (hereinafter, referred to as an optical disc) is formed in a disc shape having a center hole 1a at the center as shown in FIG. Note that the method of manufacturing the transparent substrate 1 is not the gist of the present invention, and thus the description is omitted.

Next, the preformat pattern 2 includes at least a beam guide for causing a recording / reproducing laser beam to follow a recording track. In the example shown in FIGS. 1 and 2, the beam guide portion is constituted by a spirally or concentrically formed guide groove 2a concentric with the center hole 1a, and along the guide groove 2a, an address pit or a clock is formed. Pre-pits 2b such as pits are formed. When the pre-pit 2b is formed on the guide groove 2a so as to be optically distinguishable from each other, the guide groove 2a and the pre-pit 2b are formed as shown in FIG.
Are formed at different depths. Pre-pit 2b
Are formed between adjacent guide grooves 2a, they may be formed at the same depth. In addition, instead of the guide groove 2a, a wobble pit can be formed along the recording track as the beam guide. Further, the pre-pit 2b may not be provided, and may be formed only by the guide groove.

The information recording section 3 is formed of a material having an acid group or a base property in order to cope with a redox reaction of a metal film. At the same time, the preformat pattern 2 is formed by filling the preformat pattern 2 with a material that absorbs light energy and converts it into heat energy, or a heat mode recording material containing at least a part of this type of ionic dye material. Examples of the dye material capable of forming the information recording section 3 include:
Examples thereof include polymethine dyes, anthraquinone dyes, cyanine dyes, phthalocyanine dyes, xanthene dyes, triphenylmethane dyes, pyrylium dyes, azulene dyes, metal-containing azo dyes and azo dyes. Among these, dicarbocyanine derivatives, phthalocyanine derivatives, naphthalocyanine derivatives,
Cyanine derivatives and azo dye derivatives are particularly preferably used. Alternatively, a dye material to which various quencher such as an aminium-based dye is added can be used. Further, a material in which one or more dye materials selected from the above dye material group are dispersed in a resin can be used as a material for forming the information recording section 3. Examples of the resin material capable of dispersing the coloring material include an acrylic resin, a vinyl resin, a phenol resin, a fluororesin, a silicone resin, a polyamide resin, and a cellulose resin.

The information recording section 3 is formed by spin-coating a solvent solution of a dye material selected from the dye material group exemplified above on the preformat pattern forming surface of the transparent substrate 1. Further, a groove-shaped preformat pattern 2
After the dye material is filled in the inside, the dye material adhered to the land portion 2c between the preformat patterns 2 is selectively removed, exposing the surface of the transparent substrate 1 and the dye material only in the preformat pattern 2. Can be formed. In addition, as a solvent of the coloring material, an alcohol-based solvent, a cellosolve-based solvent, or the like can be used.

Further, the object of the present invention can be achieved by containing a chelating material capable of taking the following bidentate ligand. For example, inorganic acids, dicarboxylic acids, oxycarboxylic acids, dioxy compounds, oxioximes, oxyaldehydes and derivatives, diketones and similar compounds, oxyquinones, troborones, N-oxide compounds, aminocarboxylic acids and similar compounds, hydroxyl Amines, oxines, aldimines, oxyazo compounds, nitrosonaphthols, triazenes, biurets,
Formazan and dithizones, biqualides, glyoximes, diamines and similar compounds, hydrazine derivatives,
There are thioethers. Further, derivatives having an imino group (imide, amide) can also be used.

The metal used for the metal layer 4 is not particularly limited, but a metal material such as aluminum, silver, and copper, or an alloy material containing these as a main component can be used. In particular, a metal or alloy mainly composed of silver is suitable. To be mainly composed of silver means that the silver content is 80 to 100 atomic%, especially 9%.
It is preferably 0 to 100 atomic%. Among these reflective layer materials, aluminum can be used because it is inexpensive and has been used in compact discs. When a metal material or an alloy material is used as the metal layer material, the metal layer 4 can be formed by a vacuum film forming method such as sputtering or vacuum evaporation. In this case, a technique of changing the degree of vacuum in the vacuum chamber (for example, about 10 ⁻⁵ torr) and performing sputtering to form a film having a different density or crystallization state to increase the reflectance of the metal reflection film is applied. You can also.

The protective layer 5 is made of, for example, SiO, SiN, Al
It can be formed using an inorganic material such as N or an organic material such as a photocurable resin. The inorganic protective layer can be formed by a vacuum film forming method, and the organic protective layer is a metal layer 4
It can be formed by spin-coating a photocurable resin film (for example, SD1700, SD318, SD301 manufactured by Dainippon Ink and Chemicals, Inc.), and then irradiating with resin curing light.

The thin layer 8 contains an ultraviolet curable resin, and after being applied by screen printing, the coating is cured.

When the optical information recording medium manufactured as described above is irradiated with light, an oxidation-reduction reaction of the metal film occurs.
It reacts with an electron-accepting and donating material disposed nearby to assist the flow of electrons to form a salt having a particle diameter of 10 μm or less, which can be observed with a microscope. Regarding the particle size of the salt, the smaller the particle size, the smaller the effect on the electric signal. Salts include normal salts, acidic salts, basic salts and oxide salts. If the particle size of the salt is 10 μm or less, there is no problem due to error correction,
If it is larger than 10 μm, correction becomes impossible, which may cause a problem. The particle size of the salt is 10 μm or less,
Those having a size of 10 μm or less are sometimes connected to each other and become large defects of 10 μm or more. This reaction is different from the rapid reflection film corrosion that is observed when water is attached, for example.
Progress is slow.

Regarding the increase in the particle size of the salt and the absence of salt growth, this reaction is considered to be a reaction system based on a single molecule reaction and not a chain reaction. This phenomenon becomes a major defect when the solvent remains in the information recording section 3 and the above-mentioned oxidation-reduction reaction is promoted. Therefore, after forming the information recording section 3,
After the metal layer is formed, the protective film is formed, and the solvent is dried in any of the steps after the thin film is formed.
You need to bake for more than a second.

The following is a more specific example of the present embodiment.
FIGS. 1 and 2 clarifying the effects of the present invention with experimental examples
Polycarbonate having preformat pattern shown in
Indolenin-benzoindolenine cyanide on the substrate
Dye (counter ion ClO) _Four ^-And BF_Four ^-) Solution
Was spin-coated to form an information recording section 3. This information
Ag having a thickness of 100 nm is formed on the recording portion 3 by a sputtering method.
A film was formed to be a metal film. Dai Nippon Ink Chemicals on metal layer
Coat SD318 manufactured by Kogyo Co., Ltd.
A 5 μm protective layer was formed. Next, a ray made by Jujo Kako
The cured ink was laminated. Light produced as above
50,000 lx disc (xenon lamp), 30cm distance
After 200 hours of irradiation (40 degrees, 50%),
Microscopically, fine salts that did not cause a problem in use were confirmed.
Due to the formation of this salt, a large defect of 10 μm or more becomes 53 cou.
nts / sec or less. The material of the salt is salt
It is formed from silver halide, silver sulfide, and a material having an element number of 10 or less.
Was something.

[Second Embodiment] An optical information recording medium according to a second embodiment will be described with reference to FIG. As is clear from the figure, in the optical information recording medium of the present example, the underlayer 6 is formed on the preformat pattern forming surface of the transparent substrate 1, and a groove corresponding to the preformat pattern 2 formed on the surface of the underlayer 6 is formed. Was filled with a dye material to form an information recording section 3. The underlayer 6 is provided for improving the adhesion between the transparent substrate 1 and the information recording section 3, improving the recording sensitivity, protecting the information recording section 3, and the like.
It is formed of a hydrophilic resin such as polyethylene oxide, polyacrylic acid, sodium polystyrene sulfonate, polyvinylpyrrolidone, polymethacrylic acid, polypropylene glycol, methylcellulose, polyvinylnitrate, and nitrocellulose. The formation of the underlayer 6
It can be performed by spin-coating an aqueous solution of a hydrophilic resin on the preformat pattern forming surface 2 of the transparent substrate 1. Since the underlayer 6 is made of a hydrophilic resin, it has poor water resistance (moisture resistance, moisture permeability) and heat resistance. Therefore, it is preferable that the underlayer 6 is subjected to a crosslinking treatment or a crystallization treatment to improve water resistance and heat resistance.
Specifically, after a crosslinking agent is added to an aqueous solution of a hydrophilic resin to form an underlayer 6, a crosslinking reaction by light irradiation or a crosslinking reaction by heating is caused, or an underlayer without the addition of a crosslinking agent. 6 is heat-treated and crystallized (for example, when polyvinyl alcohol (PVA) is used as the hydrophilic resin, the PVA is modified into PVA). Comparing the crosslinking treatment and the crystallization treatment, the crosslinking treatment is more preferable than the crystallization treatment because the transparent substrate 1 is not adversely affected by heating and has excellent workability.
Specific examples of the crosslinking reaction are shown below. Upon implementation, any means can be adopted as necessary from these crosslinking reactions. (1) A method in which ammonium dichromate is added as a cross-linking agent, and the surface of the dye is treated and, at the same time, the film is irradiated with reaction light after film formation to cause a cross-linking reaction in the underlayer 6. (2) A method of adding, for example, copper, boron, aluminum, titanium, zirconium, tin, vanadium, chromium, etc. as an inorganic crosslinking agent. (3) A method of acetalization using an aldehyde. (4) A method of converting a hydroxyl group into an aldehyde. (5) A method of adding an activated vinyl compound. (6) A method of adding an epoxy compound for etherification. (7) A method of causing a dicarboxylic acid reaction under an acid catalyst. (8) A method of adding succinic acid and sulfuric acid. (9) A method of adding triethylene glycol and methyl acrylate. (10) A method of blending polyacrylic acid and methyl vinyl ether maleic acid copolymer. The transparent substrate 1, the information recording section 3, the reflective layer 4, and the protective layer 5 are the same as those in the first embodiment, and thus the description is omitted.

The effects of the present invention will be clarified with reference to more specific experimental examples belonging to the present embodiment. Polyvinyl alcohol is selected as the underlayer material, and its 2.0 wt.
% Aqueous solution was formed by spin coating and stabilized using chromium as a crosslinking agent. Otherwise, an optical information recording medium was obtained in the same manner as in the first embodiment. When the obtained optical information recording medium was irradiated with light in the same manner as in the first embodiment, it was found that the medium had the same characteristics as those in the first embodiment.

Third Embodiment An optical information recording medium according to a third embodiment will be described with reference to FIG. As is apparent from the figure, the optical information recording medium of the present example has an information recording section 3 formed by filling the preformat pattern 2 with a dye.
The reflective layer 4 was laminated thereon with the intermediate layer 7 interposed therebetween, and the protective layer 5 was coated so as to cover the intermediate layer 7 and the reflective layer 4. The intermediate layer 7 is provided for improving the adhesion between the information recording section 3 and the reflective layer 4, improving the recording sensitivity, protecting the information recording section 3, and the like. A hydrophilic resin of the same kind as the base layer 6 or a material having an electron donating or accepting property corresponding to the oxidation-reduction reaction of the metal film, which can be contained in the information recording section 3 of the first embodiment, can be contained. When a hydrophilic resin is selected as the material of the intermediate layer 7, the solution can be formed by spin-coating the aqueous solution on the information recording section 3. Regarding the intermediate layer 7 as well, it is preferable to subject the spin-coated intermediate layer 7 to a crosslinking treatment or a crystallization treatment in order to improve water resistance and heat resistance. The crosslinking treatment and the crystallization treatment may be performed by the method described in the second embodiment. In addition, since the transparent substrate 1, the information recording section 3, the reflective layer 4, and the protective layer 5 are the same as those in the first embodiment, the description is omitted.

[Fourth Embodiment] An optical information recording medium according to a fourth embodiment will be described with reference to FIG. As is apparent from the figure, in the optical information recording medium of this example, the information recording area 11 is a ROM.
The present invention is applied to a so-called partial ROM type optical information recording medium divided into an area 11a and a write-once area 11b. In the ROM area 11a, a read-only information signal is formed as a pre-format pattern 2 together with a beam guide section and a header section in the form of pre-pits. On the other hand, in the additional recording area 11b, only the beam guide part and the header part are formed as the preformat pattern 2, and the unrecorded part between the header parts arranged at regular intervals on the track is used for additional information recording. Area. The additional recording area 11b can be configured similarly to the optical information recording medium of the first embodiment. Further, a printing layer can be formed on the outer surface of the protective layer. In addition, the materials of the transparent substrate 1, the information recording section 3, the reflective layer 4, the protective layer 5, the underlayer 6, the intermediate layer 7, the print layer 8, the film forming method, and the like are the same as those in the above embodiments, and thus will be described. Is omitted. Also in the optical information recording medium of this example, the additional recording area 11
Regarding b, it was confirmed that the recording medium had the same good recording and reproducing characteristics as those of the examples. Further, it was confirmed that good reproduction characteristics were obtained for the ROM area 11a when the apparatus was used in a drive device conforming to the CD or DVD standard.

FIG. 6 shows a flowchart of an example of manufacturing an optical disk according to the present invention. See the following description of S1 to S20. S1: Polish and wash the glass disk. S2: Silane coat S3: A photoresist is spin-coated on a glass disk to form a resist layer having a predetermined thickness. S4: Prebake is performed to remove the solvent. S5: The resist layer is irradiated with a laser through a condensing lens (cutting). S6: The exposed glass disk is developed. S7: The resist is heated to Tg or more to form a groove shape (first bake). S8: Baking is performed to solidify the pattern (second baking). S9: Vapor deposition, plating. S10: A metal film is formed on the uneven surface of the glass disk, and the metal film is peeled off to produce a stamper. S11: Injection molding is performed using a stamper to form a replica layer having a predetermined thickness. S12: A hard coat layer is formed on one side of the transparent substrate by spin coating. S13: An underlayer is formed on one side of the transparent substrate by spin coating. S14: A recording layer is formed on the transparent substrate by spin coating. S15: forming a reflective layer on the recording layer. S16: A protective layer was formed on the recording layer by spin coating. S17: When used in a single plate state. S18: The respective disks are bonded to form a double-sided disk. S19: This disk is stored in the cartridge. S20: The characteristics are evaluated. In the above flowchart, S7 and S8 can be performed simultaneously. For forming the groove shape, the heating temperature can be arbitrarily selected from 90 ° C. to 180 ° C. for a time of 5 to 90 minutes.

FIG. 7 is a flowchart showing details of the formation of the recording layer and the protective layer in the flowchart of FIG. See the following description of S21 to S28. S21: A substrate (disk) on which a replica layer, an underlayer (sometimes omitted), etc. are formed is prepared. S22: A recording layer is formed by spin-coating a phthalocyanine dye, a metal-containing azo dye, an alcohol solution or a cellosolve solution in which a cyanine dye and an infrared absorption dye are dissolved on a substrate. S23: Anneal at a temperature of 30 to 140 ° C. for 10 seconds or more to evaporate excess solution. S24: Wash the dye thin film. In particular, the excess dye on the outer peripheral portion is washed. S25: A solution of polyvinyl alcohol (PVA) and a crosslinking agent is spin-coated on the recording film. S26: Irradiate ultraviolet rays on the PVA coating film for 1 second or more to make PV
Crosslinking of A is performed. S27: After crosslinking, annealing is performed at a temperature of 30 to 140 ° C. for 10 seconds or more to evaporate excess solution. S28: Cross-linking water or the like to wash excess cross-linking agent
Spin coat on VA coating.

[0029]

As described above, according to the first aspect of the present invention, in an optical information recording medium in which a recording layer and a metal layer are provided directly or via an underlayer on a light-transmitting substrate, A material having an electron-accepting or electron-donating property that is oxidized or reduced by light irradiation to generate a salt at the interface between the metal layer and the recording layer. Since there is a material having accepting or electron donating properties, an oxidation or reduction reaction occurs during light irradiation,
Salt is generated at the interface between the metal film and the recording layer, and the presence of the salt suppresses the progress of corrosion of the metal film, thereby reducing large defects larger than 10 μm.

According to a second aspect of the present invention, in the first aspect, a material having an electron accepting property or an electron donating property is present in the recording layer or the intermediate layer. Salt formation can be favorably performed at the interface with the layer.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the metal layer is mainly composed of silver.
According to this, an optical information recording medium having excellent adaptability can be obtained.

The invention of claim 4 is the invention of claim 1, 2 or 3
Wherein the generated salt is a normal salt, an acidic salt, a basic salt or an oxide salt. According to these salts, the progress of corrosion of the metal film is suppressed, and a large defect larger than 10 μm is formed. Can be reduced.

According to a fifth aspect of the present invention, in the configuration of the first, second, third or fourth aspect, the particle diameter of the salt is 10 μm or less. And large defects larger than 10 μm can be reduced.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part of an optical information recording medium according to a first embodiment.

FIG. 2 is a perspective view of the optical information recording medium shown in FIG.

FIG. 3 is an enlarged sectional view of a main part of an optical information recording medium according to a second embodiment.

FIG. 4 is an enlarged sectional view of a main part of an optical information recording medium according to a third embodiment.

FIG. 5 is a perspective view of an optical information recording medium according to a fourth embodiment.

FIG. 6 is a flowchart of manufacturing a disc.

FIG. 7 is a flowchart for forming a recording layer and a protective layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Preformat pattern 3 Information recording part 4 Reflective layer 5 Protective layer 6 Underlayer 7 Intermediate layer 8 Print layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomomi Iwami 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Masaki Kato 1-3-6 Nakamagome, Ota-ku, Tokyo No. F-term in Ricoh Co., Ltd. (reference) 5D029 MA13 NA11

Claims (5)

[Claims] 1. An optical information recording medium having a recording layer and a metal layer provided directly or through an underlayer on a light-transmitting substrate, wherein the metal layer is oxidized or reduced by light irradiation in the vicinity of the metal layer. An optical information recording medium characterized in that a material having an electron-accepting or electron-donating property for generating a salt is present at an interface between the layer and the recording layer. 2. The optical information recording medium according to claim 1, wherein the material having the electron accepting property or the electron donating property is present in the recording layer or an intermediate layer provided between the recording layer and the metal layer. An optical information recording medium characterized by the above-mentioned. 3. The optical information recording medium according to claim 1, wherein said metal layer is mainly composed of silver. 4. The optical information recording medium according to claim 1, wherein the salt is a normal salt, an acidic salt, a basic salt or an oxide salt. 5. The optical information recording medium according to claim 1, wherein the salt has a particle diameter of 10 μm or less.