JPS59168944A - Optical information recording medium and its production - Google Patents

Abstract

PURPOSE:To increase the absorptivity and the reflectance and to improve the uniformity and the stability by bringing an optical information recording medium precursor into contact with a developer including one kind of compound at least selected from alkyl amines to deposit copper on physical developing nucleuses. CONSTITUTION:A physical developing nucleus layer 2 where physical developing nucleuses are dispersed in a hydrophilic colloidal dispersion medium and a copper compound-containing layer 3 are formed on a supporting material 1. A developer containing one kind of compound at least selected from alkyl amines as a developing agent is used as the developer which melts copper out of the copper compound-containing layer 3 and leads copper to physical developing nucleuses of the physical developing nucleus layer 2. After physical development, the copper compound-containing layer 5 is removed. Thus, the absorptivity and the reflectance for a high-density energy beam are increased, and the uniformity and the stability are improved.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an optical information recording medium in which information is recorded and reproduced by irradiation with a high-density energy beam such as a laser beam, and a method for manufacturing the same. relates to an optical information recording medium in which the recording layer has fine particles mainly made of copper dispersed in a hydrophilic colloid, and to a method for manufacturing the same.

[Prior art]

Information such as audio and video is stored in pits (concave areas) or blocks (
Conventionally, as a recording layer in an optical information recording medium used for a method of optically recording changes in one dimension of the shape of a convex portion, etc., and optically extracting and converting it into an audio or video signal and playing it back, Various compositions are known, but
As an example (3), metalloids such as tellurium, bismuth, and selenium, or their oxides (Yamashita et al., Proceedings of the 28th Applied Physics Conference, p. 141 (1981)), selenium, etc. Tellurium Arsenic CM - Terace et al, + P, A
ppl.

Phys, 50. No. 6881 (1979) There is a thin film recording layer made of a chalcogen compound such as luteruarsenic.

However, since such thin-film recording layers use vacuum equipment in the manufacturing process, it is difficult to continuously mass-produce the recording layer, and furthermore, the recording layer deteriorates due to oxidation of the compounds contained in the recording layer. This increases the error rate when reproducing recorded information, and many of the compounds used are toxic.

It has the disadvantage of low reliability in terms of safety.

As a solution to overcome these shortcomings, Japanese Patent Application Laid-Open No. 57-1
No. 2425, No. 57-24290 and No. 57-399
As disclosed in each publication of No. 89, there is an optical information recording medium having a recording layer formed by dispersing fine metal powder with an average particle size of 50 nm or less in a binder. However, this recording medium has a recording layer made of dispersed fine blackbody powder, and is used in a recording method that increases the reflectivity of the recording layer by laser beam irradiation. Compared to recording media used in recording methods due to reduced performance, this method has the disadvantage that it is difficult to obtain a tracking signal.

A specific example of a recording medium used in a recording method that performs recording by reducing the reflectivity of the recording layer is disclosed in Japanese Patent Application Laid-Open No. 56-10
The one disclosed in Japanese Patent No. 491 can be mentioned.

This recording medium has a recording layer in which fine particles of metal or its oxide are dispersed in a binder made of a polymer.
It has a particle size of 0A. However, since this recording medium is manufactured by forming fine particles using a toxic organic solvent and metal carzenyl as a starting material, it not only causes problems in the working environment during manufacturing, but also the fine particles are unstable. There is a drawback that the recording layer becomes non-uniform in the thickness direction due to rapid oxidation, and since the binder (5) used as a dispersion medium for fine particles of metal or its oxide is a lipophilic polymer, so-called Water-based coating is not possible, and the working environment during manufacturing is unfavorable from a sanitary standpoint. Furthermore, since this recording layer has a low reflectance of 30 inches or less, it is not preferable as a single reflected light readout type optical information recording medium.

Other specific examples of recording media used in a recording method that performs recording by reducing the reflectivity of the recording layer include JP-A No. 55-10.
No. 8995, No. 56-33995, No. 56-4929
6 and No. 56-49297 can be mentioned. This recording medium has a recording layer in which reflective silver particles are precipitated near the surface of a silver halide emulsion layer provided on a support by photographic chemical development and physical development, and the reflective silver particles are deposited near the surface of a silver halide emulsion layer provided on a support. It can be said to be a highly sensitive optical information recording medium because it contains gelatin which has excellent thermal insulation properties. However, in this recording medium, the recording layer has a thickness of 3 to 6 Itm, so not only is there a limit in sensitivity, but a gradient in silver concentration occurs in the thickness direction, and only near the surface. Since it is highly reflective, it is difficult to record and reproduce data through the support (6) and apply it to the 5 system.

On the other hand, the publications disclosing the above-mentioned prior art mainly describe only recording media in which the surface of the recording layer on the support is reflective, and such recording media do not allow bits on the surface of the recording layer to be removed from dust. In order to protect the recording medium, it is necessary to provide a protective layer such as silicon oxide or polymethyl methacrylate, or to encapsulate the entire recording medium. This process is required.

In order to avoid such complications, a method of recording through a transparent support such as polymethyl methacrylate or glass is usually used, and in this case, it is known to use transparent supports superimposed on both sides of the recording medium.

The present inventors have proposed a recording medium suitable for optical recording and reproduction through such a transparent support by filing a patent application filed in 1983-43.
◎ This recording medium proposed in the specification of No. 305 increases the reflectivity near the interface (7) between the transparent support and the recording layer, and the transparent support is designed to produce practical reflectivity near the interface. A thin physical development nucleus layer is provided on top. This recording medium has the necessary reflectivity to read information by reflected light through a transparent support and obtain sufficient signal contrast.

As a result of continuing research on the recording medium according to the above-mentioned previously proposed technology, the present inventors have discovered that an optical information recording medium having a recording layer consisting of fine particles mainly made of copper contained in a hydrophilic colloid has been developed using silver, gold, etc. It is extremely inexpensive compared to those using materials such as palladium, cobalt, and nickel, and is sufficiently less toxic than those using mercury and lead, making it preferable from the viewpoint of sanitary working environments. The present invention was completed based on the discovery that the method has excellent sensitivity and stability.

Recording materials using copper have conventionally been made by dispersing cupric oxide particles in a high molecular weight substance. Those having a photosensitive image-forming emulsion layer are known, for example, as described in the literature
otNauk, Place Komisji Mat
, Przyrod.

E, p. 23 (1956) discloses an emulsion layer comprising crushed CuCl crystals dispersed in an aqueous gelatin solution with a concentration of 10%. Also, West German Patent No. 950
In specification No. 428 (1956).

An emulsion layer is disclosed in which cuprous bromide (CuBr) produced by the reaction of cupric bromide (CuBr2) with sulfur dioxide gas (S02) or hydrogen sulfide (H2S) is dispersed in polyvinyl alcohol. Although these emulsion layers are useful primarily as light-sensitive photographic elements, they cannot be of practical use as elements of optical information recording media because of problems with graininess after development. That is, the developed copper particles have a large particle size and are not uniformly dispersed, which causes extremely serious noise.

[Purpose of the invention]

An object of the present invention is to have a recording layer with high absorption and reflectance for recording and reproducing beams through a support, and to provide a uniform recording layer.
An object of the present invention is to provide an optical information recording medium having a recording layer having excellent properties and stability.

(9) Another object of the present invention is that a recording layer can be advantageously obtained by so-called water-based coating and highly efficient physical development, is inexpensive, has low toxicity, and is safe in terms of the working environment during production. An object of the present invention is to provide a method for manufacturing an optical information recording medium that does not cause high environmental pollution.

[Summary of the invention]

The above object of the present invention is to provide a reflective recording layer of an optical information recording medium in which information is recorded and reproduced by a high-density energy beam, in which fine particles mainly made of copper are dispersed in a hydrophilic protective colloid.

An optical information recording medium precursor comprising a copper compound-containing layer containing a cuprous compound on a physical development nucleus layer on a support is processed using a developer containing at least one compound selected from alkylamines. This is achieved by forming the recording layer by means of depositing copper on the physical development nuclei in the physical development nucleus layer by bringing the recording layer into contact with the physical development nuclei.

[Structure of the invention]

In the present invention, when providing a reflective recording layer on a transparent support in which reflective fine particles mainly made of (10) copper are contained in a hydrophilic colloid, physical development nuclei are provided on the support. In addition to forming the layer, a copper compound-containing layer containing a cuprous compound is further laminated on the physical development nucleus layer to form an optical information recording medium precursor, and the layer is further laminated on the physical development nucleus layer to form an optical information recording medium precursor. Contact is made, for example, by immersion in a developer containing at least one compound, thereby depositing copper on the physical development nuclei in the physical development nucleus layer, thereby obtaining an optical information recording medium. .

In a preferred embodiment of the present invention, the thickness of the recording layer is 0.01 to 0.5 μm, and the average particle size of the copper particles is 0.
．． 0.005 to 0.2 μm, and the support is transparent and used in a system in which recording and reproduction are performed through the support. Further, it is preferable that the particle number density of the copper fine particles is I x 1015 to I x 1018 pieces/cII. By controlling the particle number density in this way, the absorption rate of the recording beam in the recording layer is further improved, and the reflectivity and reflection unevenness are reduced near the interface of the recording layer on the support side. ) It becomes possible to obtain a recording medium with higher optical density and SN ratio, and also with excellent uniformity and stability.

In the present invention, since the recording layer is a reflective layer obtained by physically developing a physical development nucleus layer coated on a support, a hydrophilic colloid is contained in the physical development nucleus layer. While keeping the number of fine copper particles constant, the average particle size can be increased by physical development, and therefore a recording layer with good uniform dispersibility can be easily produced.

In the present invention, since the recording layer is formed by physical development, a suitable particle number density can be obtained by controlling the physical development nucleus density in the physical development nucleus layer, the thickness of the physical development nucleus layer, and the physical development conditions. A recording layer comprising copper fine particles dispersed therein can be obtained. Incidentally, the particle number density of the copper fine particles can be easily determined by measuring the thickness of the recording layer of the obtained recording medium, the amount of copper contained in the recording layer, and the average particle size of the copper fine particles using, for example, an electron microscope. It can be calculated as follows.

The present invention will be explained in more detail with reference to the following drawings, but the present invention is not limited to these configurations.

FIG. 1 is a sectional view showing an example of the structure of an optical information recording medium precursor (the medium before physical development is referred to as an optical information recording medium precursor) according to the present invention. In the figure, 1
2 is a support, 2 is a physical development nucleus layer containing physical development nuclei, which is a layer in which the physical development nuclei are dispersed in a hydrophilic colloid dispersion medium, and 3 is a layer laminated on the physical development nucleus layer 2. This is a layer containing a copper compound.

In the above, as the material of the support, any material can be used as long as it is substantially transparent to the high-density energy beam, and specific examples include cellulose triacetate, polyethylene terephthalate, polymethyl Examples include methacrylate, polycarbonate, ceramic, polyimide resin, glass, and metal. Although it is not necessarily necessary that the support be subbed-treated, it is preferable that the support be sub-coated. In this case, the subbing agent may be 1, for example, a silane cassilling agent,
Silicates and titanium coupling agents (13) etc. can be used, especially as described in US Pat. No. 31'16L5.
The silane coupling agent described in No. 84 is preferred.

Further, the support may be subjected to surface treatment such as corona discharge treatment, plasma discharge treatment, ion semperdment, etc. to improve adhesion. Further, a support having guide grooves (fine relief shape) for accurately setting recording and reproducing positions can also be used.

As the physical development nucleus substance used to form the physical development nucleus layer, any known physical development nucleus substance can be used.

For example, one group includes sulfides of heavy metals (e.g., zinc, chromium, potassium, iron, cadmium, cobalt, nickel, lead, iron oxide).

Sulfides of bismuth, silver, cerium, arsenic, copper and hyrocium) are preferred, as well as heavy metal selenides such as lead, zinc, antimony and nickel selenides.

Another group of useful physical development nuclei materials include silver, (14
) Precious metals such as gold, platinum, palladium, and mercury,
Preferably, these are present as colloidal particles in the hydrophilic colloid. Also.

Salts of such metals, preferably simple inorganic and easily reducible salts such as silver nitrate, gold chloride and gold nitrate, are also useful as physical development nuclei.

Another group of useful physical development nucleus substances include thio compounds 1
For example, silver thioxate and its lead and nickel complex salts,
Examples include thioacetate and the like.

In the present invention, the physical development nuclei include the various heavy metals, noble metals, and sulfides thereof described above.

Selenides or the like can also be provided on the support by an appropriate method such as vapor deposition, sputtering, or chemical vapor deposition. Such methods such as vapor deposition, sputtering, and chemical vapor deposition can make the layer containing the physical development nuclei very thin, and therefore have the advantage of effectively utilizing the energy of the recording beam. In this case, the film thickness is 5~
1000A, preferably 20-500A.

Preferred (15) physical development nuclear materials are single heavy metal sulfides, such as sulfides such as zinc, cadmium, silver, lead, etc., and metals such as silver, gold, palladium, copper, etc.

The particle size of the fine particles forming the physical development nuclei needs to be sufficiently small in order to carry out effective physical development,
0.002 to 0.2 μm, preferably 0.01 to 0.2 μm
0.05 pm.

Any method may be used to provide the physical development nucleus layer as described above on the support. For example, [1] a physical development nucleus layer may be obtained by coating a liquid obtained by dispersing the physical development nucleus material in a hydrophilic colloid dispersion medium on a support; After forming a thin film of a nuclear material by vapor deposition or sputtering, a physical development nuclear layer may be obtained by overcoating with a hydrophilic colloid dispersion medium. A physical development nucleus layer may be obtained by applying a dispersion medium onto a support and then forming a thin film of a physical development nucleus substance by a vapor deposition method or a sputtering method. Among these, the above [1] or [
2] method. Note that a chemical vapor deposition method, a liquid phase formation method, or the like may be used instead of the vapor deposition method or sputtering method. Further, as the coating method used at this time, any coating method such as blade coating, air knife coating, par coating, roll coating, curtain coating, and spinner coating can be adopted.

The thickness of the physical development nucleus layer obtained in this way is Olo
It is about 1 to 0.5 pm, preferably 0.01 to 0.
．． It is 1 μm.

The colloidal dispersion medium forming the physical development nucleus layer includes:
Known hydrophilic colloids in which physical development nuclei can exist stably and uniformly as colloidal particles can be used,
Specific examples include gelatin, alkali-treated gelatin, acid-treated gelatin and gelatin derivatives, and colloidal albumin.

Casein, cellulose derivatives (calcexymethylcellulose, hydroxyethylcellulose, etc.).

Sugar derivatives (sodium alginate, starch derivatives, etc.), synthetic hydrophilic polymers (poly-N-vinylpyrrolidone, etc.).

(polyacrylic acid copolymer), etc. Two or more of these may be used in combination (17) if necessary. Preferred among these colloidal dispersion media are hydrophilic colloids with poor thermal conductivity, acrylic acid resins with a copolymer composition containing at least an acrylic acid salt or a methacrylic acid salt as a monomer unit, and water-soluble cellulose. Derivatives and gelatin are preferred.

On the other hand, hydrophobic polymeric substances have weak protective colloid properties and.

It is not used because it hinders the progress of physical development that involves the diffusion of copper ions.

The copper compound used for forming the copper compound-containing layer, that is, the layer that supplies copper atoms to the physical development nuclei of the physical development nucleus layer by physical development, includes cupric halides such as CuCl, CuBr, and CuI, or cupric halides such as CuCl, CuBr, CuI, etc. Mixed crystal.

CuSCN or CuCl2, CuBr2. CuI2
Cupric halides such as CuS or mixed crystals thereof, CuS
O4, Cu(NO3)2, etc. can be used. In particular, in order to efficiently supply copper atoms to the physical development nuclei, it is preferable that the copper compound-containing layer is a layer containing a sparingly soluble salt, and in this case, cupric halide is particularly preferred. used.

(18) The copper compound may be contained in the physical development nucleus layer, or may be provided as a separate layer on the physical development nucleus layer.

The cupric halide emulsion preferably used in the present invention can be prepared by the method described in Japanese Patent Application No. 56-24669 and its cited references. That is, a cupric halide emulsion is obtained by reducing divalent copper ions with a reducing agent in an acidic aqueous solution containing a hydrophilic polymer compound.

FIG. 2 is a sectional view showing an example of the structure of an optical information recording medium after the optical information recording medium precursor is physically developed. In the figure, 4 is a recording layer to which copper is supplied by physical development and exhibits reflectivity, and the layer containing physical development nuclei has changed from the original layer. Physical development also occurs near the interface of this recording layer 4 on the support side. progresses, and copper fine particles are present throughout the recording layer 4. 5 is a copper compound dispersed layer in which the amount of copper is reduced as a result of physical development.

The physical development for forming the recording layer 4 is a first-order (19) This is done according to a similar mechanism.

(1) Generation of cuprous ions or their complex ions by the copper compound contained in the copper compound-containing layer and diffusion process of these ion species to the physical development nuclei (2) Formation from the cuprous ion species on the physical development nuclei The first step (1) is a process in which the copper compound in the copper compound-containing layer is a cuprous compound, in which it is dissolved and diffused in the developer, while the copper compound is If it is a cupric compound then it is dissolved in the developer solution.

This is a process in which cupric ions become cuprous ions by a suitable reducing agent contained in the developer, and these ions diffuse.

The second process (2) is a process in which a disproportionation reaction of cuprous ions occurs according to the following formula.

2Cu-1→Cu+Cu2+ By utilizing such a disproportionation reaction, physical development can be achieved extremely advantageously compared to a method of producing metallic copper by reducing copper ions. That is, Japanese Patent Application Publication No. 59-168944 on the reduction reaction of copper ions.
(8) The standard unipolar potential E based on the standard hydrogen electrode is as follows.

Cu+e==Go Cu E= 0.520 (
V) Cu+2e=Go Cu E= 0.337
(V) As described above, the value of the standard unipolar potential E of copper is never large, and therefore, in order to reduce copper ions through a reduction reaction, it is necessary to use a reducing agent with considerably large reducing power. However, the use of such reducing agents is accompanied by practical problems.

To promote the above-mentioned disproportionation reaction, cuprous,
+ High concentration of iono Cu, cupric ion Cu2
Cuprous halide compounds have a higher solubility in water than, for example, silver halides, and therefore maintain a high concentration of cuprous ions in the applied developer. It is easy to do. Further, removal of cupric ions can be carried out using a chelating agent that forms a complex with the cupric ions.

As described above, the physical development for forming the recording layer is based on the disproportionation reaction of cuprous ions, and is not development based on the reduction reaction (21) unlike the conventional development using silver. That is, physical development using a silver halide emulsion is carried out by diffusion of an Ag complex into physical development nuclei and a reduction reaction therein (for example.

T-HJam6s, '''The Theory of
the Photographic process
(See Chapter 16 (1966) and Japanese Patent Application Laid-open No. 56-49296). This means that the standard monopolar potential of silver ions is approximately 0.8.
This is because it has a high voltage of 0.00 (V) and is easily reduced.

From the above, it is necessary to use a developer containing a compound that promotes the progress of the first and second processes described above in the physical development for forming the recording layer. Specifically, a developer containing a chemical compound or compound system that has an appropriate coordination ability for cuprous ions and a larger coordination ability for cupric ions. is preferred, and further when the copper ion is a cupric compound.

It is necessary to use a developer containing a compound necessary for reduction to cuprous ions and thus having an appropriate size of reducing property.

In this invention, at least one compound selected from alkylamines is used as a developer that leads to the physical development nuclei in the fine physical development nucleus layer. A developer containing the following is used. Particularly preferred are those that form a five-membered ring chelate complex with cupric ions.

Specific examples of alkylamines that can be suitably used in the present invention include ethylenediamine, N-methylethylene/quamine, and N-ethylethylenediamine%N-
n-propylethylenediamine.

N-isopropylethylenediamine, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N*-N-dimethylethylenediamine.

-n-furovylethylenediamine %N, N, N,
N-tetramethylethylenediamine% 1,2-diaminopropane% meso-2,3-diaminobutane,
rae-2,3-diaminobutane, trimethylene diamine.

eta-1,2-diaminocyclohexay, tra
ns-1,2-diaminocyclohexane, tra
ns -1,2-(23) diaminocyclohebutane, 1,2.3-) diaminopropane, 1,3-diamino-2=aminomethylpropane,
3.3-diaminodizolobylamine, and others.

Preferred solvents used in the physical developer in the present invention include pure water and alcohols (for example).

(methyl alcohol, ethyl alcohol, etc.), /IJ alcohols (eg, ethylene glycol, diethylene glycol, etc.), and these solvents may be used alone or in an appropriate combination of two or more.

Furthermore, in addition to the developer, the above-mentioned physical developer contains various additives in order to obtain development characteristics (developing speed, improved shelf life of the developer, etc.) or optical properties such as appropriate reflectance and absorbance 1 spectral characteristics. Additives can be added. The main additives include, for example, alkaline agents (e.g., alkali metal or ammonia hydroxides, carbonates, phosphates), pH
Conditioning or buffering agents (e.g., weak acids such as acetic acid, boric acid).

(weak bases or their salts), preservatives (for example, sulfites, acid sulfites, hydroxylamine hydrochloride, formaldehyde bisulfite salt adducts, alkanolamine bisulfite adducts, etc.). The pH of the developer is preferably 7 to 13.

The concentration of the developer in the above-mentioned physical developer varies depending on the type of developer and cannot be unconditionally defined, but it is usually 0.01 to 1.
The development temperature is usually 10 to 40.
It is said to be around ℃.

In the optical information recording medium of the present invention, for example, the copper compound-containing layer 5 shown in FIG. 2 is removed in a physical developer.

As shown in FIG. 3, the structure may be such that the copper compound-containing layer is removed. Copper compound-containing layer 5 after this physical development
The operation for removing can be carried out by, for example, peeling or dissolution. This peeling operation is performed during the water washing process after physical development.

The temperature during water washing is raised to a temperature at which the hydrophilic colloid dispersion medium in the copper compound-containing layer 5 dissolves or becomes a sol (
Hereinafter, this will be simply referred to as "warm water cleaning." ). In this hot water washing, it is preferable to harden the recording layer 4 using a hardening agent (25), so that the copper compound-containing layer 5 can be effectively peeled off. As another method, the copper compound-containing layer 5 can be suitably peeled off by immersing it in a concentrated strong electrolyte aqueous solution to cause the film to shrink, and then washing it with hot water. As the electrolyte, a salt of a strong acid and a strong base, such as sulfuric acid or IJium, is preferred. Further, similar effects can be obtained when the above-mentioned strong electrolyte is contained in a physical developer. The liquid temperature in the hot water washing mentioned above is 1
For example, when the dispersion medium of the copper compound-containing layer is a hydrophilic colloid and this hydrophilic colloid dispersion medium is gelatin,
The temperature is 20 to 50°C, preferably about 40°C and 5°C. The thickness of the recording layer in the optical information recording medium of the present invention is 0.5°C.
01 to Q, preferably 5 pm, more preferably 0.03 to 0.2 μm. Thickness is 0.01μm
If the thickness is less than 0.5 μm, coating unevenness will become apparent and it will be difficult to form a uniform and stable recording layer.
If it exceeds 26, the reflectivity of the recording medium becomes low (26), making optical reading difficult, and signal contrast may decrease.

Further, the average particle size of the copper fine particles dispersed in the recording layer weight is 0.
0.005 to 0.2 μm, more preferably 0.01 to 0.1 μm. Average particle size is 0.0
If it is less than 0.05 μm, the recording energy beam absorption rate and the reproduction energy beam reflection rate decrease, and recording and reproduction may become almost impossible.

On the other hand, if the average particle size exceeds 0.2 μm, a decrease in absorption rate and unevenness in reflectance occur due to agglomeration of fine copper particles, and recording and reproducing characteristics may deteriorate.

Note that the average particle size herein refers to the average value of the longest width and the shortest width of the copper fine particles. In addition, regarding the particle size distribution of copper fine particles having such an average particle size, it is preferable that the particle sizes are uniform, and about 6.04 of the total number of ordinary steel particles is ±5 of the average particle size.
The optical information recording medium of the present invention has a reflectance of 10 to 80%, preferably 20 to 70% through the support, since it is necessary to read information with one reflected light. 27) It is necessary that the light source has a reflectance for reproduction light.If the reflectance is less than 10%, the S/N ratio decreases, making it difficult to read information.

The optical information recording medium of the present invention may be subjected to heat treatment in the presence or absence of oxygen, if necessary, for the purpose of increasing the reflectance or decreasing the film thickness. The preferred heating temperature range in this case is about 250 to 400°C.

[Action/effect of the invention]

FIG. 4 is a cross-sectional view showing an example of an optical information recording medium of the present invention in which bit information is recorded. In this example, a high-density energy beam is irradiated from the direction of the support 1 to irradiate the recording layer 4. By melting or blowing away the parts (blo
w off ) bit 7 is formed. 6 is an arrow indicating irradiation with a high-density energy beam.

According to the present invention, by utilizing the reduced reflectivity of the pits 7, information can be read and reproduced using a high-density energy beam that is weaker than the high-density energy beam for writing.

JP-A-59-IG8944 (8) In the present invention, high-density energy beams that can be used to record bit information include xenon lamps, mercury vapors, arc lamps, laser beams, etc. Of these, laser light is preferred because it allows high-density recording.

As the laser light, either continuous wave oscillation or nosolus oscillation can be used. Can be used 7) L/-
Specifically, Ruby Racer (wavelength 6943A)
, Alvin ion racer (wavelength 4880A, 514
5A), glass laser (wavelength 1.06μm), helium-neon laser (wavelength 6328A), chryzoton ion laser (wavelength 6471A), helium-cadmium laser (wavelength 4416A% 3250A), dye laser, semiconductor laser, etc. can be mentioned.

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,
Although it is preferable to irradiate through the transparent support, it is also possible to irradiate directly onto the recording layer surface side opposite to the transparent support.

The present invention has been explained above.According to the optical information recording medium of the present invention, the recording layer is reflective in which fine particles mainly composed of copper are dispersed in a hydrophilic colloid dispersion medium. Since the absorption rate for high-density energy beams increases, high-performance recording can be performed.
Moreover, since the reflectance increases, high-performance reading can be performed, and thereby sensitivity and signal-to-noise ratio can be significantly improved. Further, by controlling the particle number density of the fine particles within an appropriate range, it is possible to obtain excellent uniformity and stability. In addition, since the dispersion medium in the recording layer is a hydrophilic colloid, the recording layer can be obtained by aqueous coating, and as a result, unlike conventional methods, organic solvents are not used during manufacturing, resulting in a highly safe working environment. Obtainable. Since the fine particles are mainly made of copper, manufacturing costs can be reduced, and steel is less toxic and safe to handle (30). The spectral characteristics of the recording layer depend on the complex refractive index and filling wheel that the dispersed fine particulate metal has in the bulk state, as well as the refractive index of the dispersion medium (J.
t, Ph1los, Trans, R,Soc,
Lond, 203, p. 385 (1904)), of which the dominant factor is the complex refractive index that the dispersed particulate metal has in the bulk state. In the recording medium of the present invention, the above-mentioned fine particulate metal is copper, but what is the complex refractive index of copper? As shown in Table 1, the values of the real part n and the extinction coefficient in the formula representing % vary greatly depending on the wavelength, and are also completely different from those for silver shown together.

From this, it is understood that the recording medium of the present invention can be applied to light of wavelengths that could not be applied to conventional media in which the bulk metal is silver.

(31) Table 1 Specifically, the spectral sensitivity of a recording medium having a recording layer made of silver is about 500 to 600, as shown by the a-line A in FIG.
whereas it exhibits maximum sensitivity near nm.

A recording medium having a recording layer made of copper has a maximum sensitivity in the vicinity of approximately 700 to 800 nm, as shown by curve B, and therefore the oscillation wavelength is usually in the infrared region as a high-energy beam for recording and reading. This makes it possible to realize an optical information recording/reproducing device that is smaller and cheaper than when a gas laser is used.

Copper halide is preferred as the copper compound used as the copper atom source, but since this halide steel does not exhibit photosensitivity, it can be handled in a bright room, which has a great manufacturing advantage.

In addition, in the present invention, since a developer selected from alkylamines is used as a developer for physical development, as will be clear from the description of the examples below, copper precipitation on the physical development nuclei is highly suppressed. It can be done efficiently. This is because alkylamines perform their desired functions with high efficiency in each of the physical development processes described above, but in particular they form stable chelate complexes with cupric ions produced by the disproportionation reaction of cuprous ions. This is thought to be due to the fact that it is formed and the disproportionation reaction proceeds efficiently. As a result of being able to perform physical development with high efficiency in this manner, a small amount of copper atom source is sufficient, and therefore it is possible to reduce the thickness of the copper compound-containing layer.

Further, the dispersibility of the copper compound is improved, and it becomes easy to improve the uniformity of the copper compound-containing layer.

These effects that characterize the present invention cannot be obtained by techniques for producing thin films containing fine metal particles dispersed in metals other than copper, such as (33) pulverization of metal lumps, high-temperature sintering, or vapor deposition methods.

〔Example〕

Examples of the present invention will be described below, but the present invention is not limited thereto.

16% aqueous solution of chloroauric acid 1% by weight of sodium borohydride 4
0-t binder aqueous solution (concentration 1% by weight)
12-r- with pure water
430 (The binder is a mixture of 1 part by weight of gelatin and 4 parts by weight of topolyvinyl alcohol derivative.)
The above substances were stirred at a temperature of 20°C for 10 minutes, and the concentration of gold was 0.095% by weight and the concentration of colloid was 0.025% by weight.
A colloidal gold solution in which the average particle size of fine gold particles was 3OA was obtained.

A surfactant and a hardening agent are added to this colloidal gold solution, and this is coated on a support made of a polymethyl methacrylate plate with a thickness of 1.2 volts which has been subjected to an undercoating process, using a spinner coating device to obtain a film with a thickness of Apply so that it is 0.03 μm,
After drying, a substantially colorless and transparent physical (34) development nucleus layer was formed.

On the other hand, solufiA and solufiB having primary compositions were prepared.

Solution A: Ossein Gelatin 182 Potassium Bromide 224 V Potassium Iodide
088 fL-ascorbic acid
32D f pure water
1200 1PLL solution B: Cupric nitrate trihydrate
42.4F pure water
600 mt solution B was maintained at an upper temperature of 40°C and a stirring temperature of 40°C, and solution B was added instantly. The temperature of the resulting mixed solution was maintained at 40°C and stirring was continued for 3 minutes, followed by desalting treatment. After washing with water, ossein gelatin 24
9 was added and subjected to ultrasonic dispersion treatment for 10 minutes, thereby obtaining a cupric iodobromide emulsion (total amount 5009 ft). This emulsion has a pH of 3.5. The weight ratio of copper and gelatin contained is approximately 0.5. The particle size of the cupric halide particles measured by transmission electron micrograph was 0.05 μm.

This cupric iodobromide emulsion is applied onto the physical development nucleus layer (35) using a spinner coating device so that the film thickness after drying is 2.5 μm, and dried to form a copper compound-containing layer.
Thus, an optical information recording medium precursor was produced.

Five such precursors were prepared and 0.2 of the developer shown in Table 2 was prepared.
Each precursor was developed by immersing it for 3 minutes at a temperature of 25°C in a developing solution consisting of a malti aqueous solution whose pH value was adjusted to 9 using a buffer solution, and then washed with warm water at a temperature of 37°C to develop the copper. The compound-containing layer (emulsion layer) was peeled off, thereby obtaining four types of samples (Samples 1 to 4) and one type of comparison sample (Comparative Sample).

When the obtained sample and comparative sample were observed from the support side,
For Samples 1 to 4, the formation of copper mirrors with metallic luster was observed, but no copper mirrors were observed for the comparative samples.

In addition, for each sample and comparative sample, the processing time required to complete development and the thickness of the formed recording layer.

In addition, the reflectance and absorbance of light at a wavelength of 830 nm were measured. Furthermore, each of the sample and comparison sample was set on a turntable and rotated, and the beam was
G8944 (1G) Wavelength 830 nm focused to a diameter of 1.4 μm
A semiconductor laser beam of
Writing and recording was performed by forming bits in the recording layer by giving the following information.

The intensity of the laser beam on the recording layer of the sample was 10 mw during recording and 2 mw during reproduction, and the recording S/N ratio was measured at a bandwidth of 30 KHz.

The results are shown in Table 2.

As can be understood from the results shown in Table 2, according to the present invention (37), physical development can be carried out with high efficiency and an optical information recording medium with excellent characteristics can be obtained. On the other hand, even when an aromatic amine was used as a developer, almost no growth of steel particles was observed9.

FIG. 6 is a curve diagram showing the spectral sensitivity characteristics of sample 3, and as is clear from this diagram, it has high sensitivity to light in the wavelength range of about 700 to 900 nm.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the optical information recording medium precursor before physical development, FIG. 2 is a sectional view of the optical information recording medium according to the present invention after physical development, and FIG. 3 is a cross-sectional view of the optical information recording medium precursor after physical development. FIG. 4 is a cross-sectional view of the optical information recording medium according to the present invention after the compound-containing layer has been removed, FIG. 4 is a cross-sectional view of the optical information recording medium according to the present invention after high-density energy beam irradiation, and FIG. FIG. 6 is a curve diagram showing the spectral sensitivity when the metal of the recording layer is silver and copper. FIG. 6 is a characteristic curve diagram showing the spectral sensitivity of an example of the optical information recording medium according to the present invention. l...Support 2...Physical development nucleus layer 3.
... Copper compound-containing layer (38) 4 ... Recording layer (physical development nucleus layer after physical development) 5 ...
Copper compound-containing layer 6 after physical development...High-density energy beam 7...BIT JP-A-59-168944 (11)

Claims (1)

[Scope of Claims] 1) An optical information recording medium in which information is recorded and reproduced using a high-density energy beam, which has a recording layer in which fine particles mainly made of copper are dispersed in a hydrophilic colloid; The layer is formed by the action of a developer containing at least one compound selected from alkylamines.
An optical information recording medium characterized in that it is formed by depositing copper on physical development nuclei of a physical development nucleus layer. 2) In a method for manufacturing an optical information recording medium in which information is recorded and reproduced using a high-density energy beam, an optical medium comprising a copper compound-containing layer containing a cuprous compound is provided on a physical development nucleus layer on a support. By contacting the information recording medium precursor with a developer containing at least one compound selected from alkylamines, copper is precipitated on the physical development nuclei in the physical development nucleus layer (2), and the following A method for manufacturing an optical information recording medium, comprising the step of forming a reflective recording layer in which fine particles mainly made of copper are dispersed.