JPS58219089A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To reduce reflection noises and obtain an optical information recording medium capable of obtaining favorable reproduced signals, by a method wherein a physically developed core layer comprising a metal or a semimetal dispersed in a layer comprising an organic substance is provided as a recording layer of an optical information recording medium. CONSTITUTION:An organic material layer 2 of a natural organic polymer (e.g., gelatine, casein), a water-soluble resin (e.g., polyacrylamide) or the like is provided on a base 1 formed of cellulose triacetate or the like and being substantially transparent to laser light or the like, preferably after undercoating the base 1 with a silane coupling agent or the like. Then, a thin film 3 of a metal (e.g., Ag, Au) or a semimetal (e.g., Te, Bi) is provided thereon by vapor deposition or a sputtering method, and the system is left to stand so that the atoms of the metal or the semimetal are diffused into the organic material layer 2. Thereafter, physical development is conducted by using a developing liquid containing a developer such as p-methylaminophenol sulfate or hydroquinone to produce a physically developed core layer having an enhanced reflectivity and a very low thermal conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical information recording medium that has a recording layer on a substrate and records and reproduces information using a high-density energy beam. The present invention relates to an optical information recording medium characterized in that the physical development nuclei of the physical development nucleus layer are metals or metalloids diffused into a layer containing an organic substance.

High a of laser light that can provide high illumination and short exposure
[In high-density recording media that use energy beams as information recording and reproducing means, rDRAWJ (Direct React
Recording media having the following characteristics have recently been used as memory media for video information such as text files and image files.

The thin film conventionally known as the recording layer of the recording medium is a semimetal such as Te, old selenium, or an oxide thereof.
It consists of chalcogen compounds such as e-Te-As and Te-As. However, since such a recording layer uses a vacuum device in the manufacturing process, it is not suitable for continuous mass production, and furthermore, it is prone to errors during reproduction of recorded information due to oxidative deterioration of the compounds contained in the recording layer. This method had the drawbacks of an increased citric acid rate, and weak evidence of the safety of the compounds used.

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

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

SUMMARY OF THE INVENTION Accordingly, a first object of the present invention is to provide an optical information recording medium that solves the drawbacks of the above techniques, reduces noise, and provides a good reproduced signal.

In addition, in Japanese Patent Application No. 56-180682, the present inventors proposed an optical information recording medium in which a recording layer is a layer in which metal atoms or L semimetal atoms are diffused into an organic layer. However, it has been found that it is difficult to control the particle size of the fine particles made of metal atoms diffused into the organic layer, and it is therefore still difficult to produce a medium having a desired reflectance.

Therefore, a second object of the present invention is to provide an optical information recording medium that can solve the drawbacks of the above-mentioned techniques in accordance with the first object.

The above object of the present invention and other objects described below are directed to an optical information recording medium in which a recording layer is placed on a substrate and information is recorded and reproduced using a high-density energy beam. The physical development nuclei of the development nucleus layer are
This is achieved by an optical information recording medium characterized in that it is a metal or metalloid diffused into a layer containing an organic substance. ...The first word in the present invention, "diffusion", is defined in the Physical and Chemistry Dictionary (Iwanami Shoten Edition)
As described in the formula, it refers to the process of change in the distribution distribution that occurs when a mixed system of different types of particles approaches a state of thermal equilibrium.

That is, metal atoms or metalloid atoms that are not previously present in the organic layer (a layer containing an organic substance) or that are present in small amounts move from the metal or metalloid layer provided on the organic layer and are implanted. (by) increasing their concentration.

・The recording layer of the present invention is formed by developing metal atoms or metalloid atoms diffused into an organic material layer as physical development nuclei.Although the reason is not clear, the physical development of metal particles after development An optical information recording medium with almost no concentration irregularities of metal fine particles in the development nucleus layer, low noise with respect to incident light from the substrate side, and high reflectance, that is, a good reproduction S/N ratio. You can get it.

Furthermore, according to the present invention, the particle size of the metal fine particles or metalloid fine particles diffused in one organic substance layer can be increased by physical development, so that fine particles of any particle size can be added to the physical development nucleus layer. Can be distributed with any device. In other words, it is possible to easily obtain an optical information recording medium having any reflectance and absorption at any wavelength.

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

FIG. 1 shows a cross section of the precursor [1) of the optical information recording medium of the present invention. In the figure, reference numeral 1 denotes a substrate, which may be any material as long as it is substantially transparent to high-density energy beams such as laser light. Specific examples thereof include cellulose triacetate, polyethylene terephthalate, polymethyl methacrylate, Examples include polycarbonate, ceramic, polyimide resin, glass, metal, etc., and these substrates are preferably undercoated. In this case, as a subbing agent, a silane coupling agent, a titanium coupling agent, etc. can be used, and in particular, US Pat.
The silane coupling agents described in US Pat. No. 61,584 are preferred. In addition, corona discharge treatment, plasma discharge treatment,
Surface treatments such as ion bombardment may be applied to the substrate to improve adhesion. Also, guide grooves (a thin relief shape) for accurate setting of recording and playback positions.
A substrate having the same structure can also be used in the same manner.

2 is an organic layer, preferably a thin film mainly composed of an organic polymer compound, that is, a binder. If metal is not added to the base, metal atoms or metalloid atoms can easily diffuse from the semimetal layer 3, such as natural organic polymer compounds such as gelatin, casein, and heptalulose, and water-soluble resins such as polyacrylamide and polyacrylic acid, or ionic compounds. Resins are preferred as the organic substance used in the present invention.

In addition, organic substances used in the present invention include styrene resin, acrylic resin, vinyl chloride-vinyl acetate copolymer, vinyl acetate-methyl methacrylate copolymer, styrene-butadiene copolymer, vinyltoluene-butadiene copolymer,
Resins such as polycarbonate resins, polyurethane resins, phenolic resins, Epoquine resins, melamine resins or 7-run resins can also be used. These can also be used in combination of two or more types as necessary.

The organic material layer can be easily obtained by applying an organic material solution. l the solution! ll! The solvent for conditioning is water,
A solvent that can disperse or dissolve any organic substance, such as a low-boiling organic solvent (ethanol, ethyl acetate, etc.), can be used. The application method is a blade! ! Any coating method can be used, such as I cloth, air knife coating, par coating, curtain coating, spinner coating or roll@cloth. The dry film thickness is 0.05 to 20 μm, and preferably 0.05 μm to 1 μm in consideration of coating unevenness.

Further, the organic material layer of the present invention may be a layer containing an organic material in which colloidal metal atoms are already dispersed before the metal atoms or metalloid atoms are diffused into the layer.

The colloidal metal atoms do not necessarily have to be the same as the diffusing metal atoms.

As another method for manufacturing an organic layer, a uniform thin film can be formed using a vapor phase growth method such as a CVD method, for example, a plasma CVD method.
A polymer film of an organic compound having a double bond can be obtained by method D.

The recording characteristics can be further improved by adding a dye or pigment that absorbs at the wavelength of the high-density liver energy beam for recording into the organic layer. The pigments that can be used are preferably ones that are hard to deteriorate, such as azo, anthraquinone, indigoid, phthalocyanine, carbonium including triphenylmethane, quinoneimine, methine, quinoline, nitro, nitroso, Benzoquinone type etc. are used. As inorganic coloring pigments, cobalt-based, manganese-based, chromium-based, cadmium-based, iron-based pigments, ultramarine blue, navy blue, and the like are also used.

The metal or metalloid thin film 3 in FIG. 1 can be provided by vapor deposition, sputtering, CVD, or the like. The film thickness is set to such an extent that all of the metal or metalloid is completely diffused into the organic layer during the diffusion process, and varies depending on the type of metal or metalloid used. This metal or metalloid thin film is formed into an organic material layer 2 as shown in FIGS. 1(A) and 1(B).
It may be provided either on the substrate side or on the opposite side. The metal or metalloid used in the thin film is one that easily diffuses into the organic layer. For example, as a metal, Ag
.

Au, Pt, Cu, Pd, Ni, etc. are used, and semimetals such as Te, Bi, Se, Sb, etc. are used, and Ag, which is particularly easily diffused, and To are preferable.

FIG. 2 shows a recording medium precursor [2] formed by diffusion of metal atoms or metalloid atoms by leaving the recording medium precursor [1] shown in FIG. 1 for several hours to several days. ] is a cross-sectional view. 2 is an organic layer in which metal atoms or metalloid atoms are diffused, and the concentration gradient of the diffused metal particles or metalloid particles on the surface side is larger than that on the substrate side. 4 is a diffused metal particle or metalloid particle which exists in an island state in an organic substance, and since there is no contact between the particles, the surface of the diffused organic substance layer has poor electrical conductivity.

FIG. 3 is a sectional view showing the structure of the optical information recording medium of the present invention after physical development of the recording medium precursor [2] shown in FIG. 2. FIG. FIG. 3 shows a physical development nucleus layer to which a metal is supplied during physical development to improve reflectivity.

In this layer, the particles remain non-contact even after physical development, resulting in poor electrical conductivity, that is, very low thermal conductivity, and the high-density energy beam intensity required for pit formation. The advantage is that it requires less.

The metal or metalloid supplied by physical development is supplied from a metal compound-containing layer provided on the physical development core layer or a developer containing a metal compound.

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

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

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

As a metal compound that supplies metal atoms by physical development to the physical development nucleus used in the present invention, gold salt (for example, metal salt) is used.
IJum salt), copper salt (e.g. cucz2, Cu5C
N), lead salts (e.g. PbO, PbCl2, PbBr
z), iron salts (e.g. oxalates, nitrates), Fe complex salts (
For example, oxalic acid, malonate), silver salt (for example, AgC1
,,Agl'lr,AgI,AgNO2,Ag
25Oq, Ag25), cobalt salt (e.g. CoC
l2, Co5011), nickel salts (e.g. Ni(
NO3)2. NIC12), other HgCt2,
BiCl2, TaCl3, InC/4, I
Although nBr3 etc. can be used, in the present invention, silver salts, copper salts, nickel salts, and cobalt salts are particularly preferably used.
Silver halide is most preferred. In this case, silver halogenide also has the advantage of being non-polluting.

The grain size of the silver halide is 0. O1am~1μm, preferably 0.02am~0. It is l11m.

When a silver halide emulsion is used as the metal compound in the present invention, it is desirable to add an antifoggant, a coating aid, and a hardening agent, but since sensitivity to visible light is not required, sensitization is not necessary. There is no need to take any measures. It is also possible to add a developing agent, such as hydroquinone or phenidone, directly to the silver halide emulsion and develop it using only an alkali powder containing a silver halide solvent to precipitate silver in a silver mirror shape. be.

In the present invention, when the metal is supplied from the 4i developing compound-containing layer provided on the physical development nucleus layer, it is preferable to use a force that removes the layer after physical development. The layer is removed by, for example, peeling, dissolving or beer-parting. The above peeling operation is carried out by increasing the wet hair level during washing to a point where the hydrophilic colloid dispersion medium of the metal compound-containing layer dissolves or becomes a sol during the water washing step after physical development. At this time, the metal compound-containing layer is preferably peeled off effectively by hardening the physical development nucleus layer, that is, the recording layer, by using a hardening agent. Alternatively, the metal compound-containing layer can be preferably peeled off by immersing it in a concentrated strong electrolyte aqueous solution and washing the ridges where the membrane shrinks with wet water with wet water.

The strong electrolyte used in this case is preferably a salt of a strong acid and a strong radical, such as sodium sulfate. Further, a rotating effect can be obtained even when the above-mentioned strong electrolyte is used by being included in a physical developer.

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

Figure 4 shows that when a high-density energy beam is irradiated from the direction of the substrate, the irradiated portion of the recording layer is melted or blown away (
Blew off ), which shows a cross-sectional view of an optical information recording medium according to the present invention in which bits are formed.

In the figure, 6 is an arrow indicating the irradiation of the high-density energy beam, and T indicates the formed pit.

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

Although known high-density energy beams for recording bit information used in the present invention can be used, laser beams are preferred.

This laser can be used with continuous wave oscillation or pulse oscillation. Lasers that can be used include ruby laser (6943λ), alpha ion laser (488 (1:, 5145λ)), glass laser (
'1.06μ), He-Ne laser (6328λ
), Clifton Ion Ray f-(6471^), He-
Examples include CdL/- laser (4416^, 3250A), dye laser, semiconductor laser, and the like. Other high density energy beams such as xenon lamps, mercury lamps, arc lamps, etc. can also be used in the present invention.

The high-density energy beam for recording on the recording medium according to the present invention and the high-density energy beam for reproducing may be of the same type or different types, and are generally irradiated through a transparent substrate. , there is no problem even if it is used by directly irradiating the surface side of the recording layer.

FIG. 5 shows a cross-sectional view of an optical information recording medium in which a photosensitive layer is used as the metal compound-containing layer of the present invention and pattern exposure is woven on the surface of the layer.

In the figure, parts with the same symbols as in FIG. 2 indicate the same parts as above. 12 is a photosensitive metal compound-containing layer, 8 is a pattern, 9
indicates a high-density energy beam suitable for sensitizing a layer containing a photosensitive metal compound.

As the above-mentioned photosensitive metal compound in this example, the above-mentioned silver halide is preferably used.

When using an information recording medium in which a photosensitive metal compound-containing layer is laminated on a physical development nucleus layer as in this example,
By pattern exposure on the surface of the photosensitive layer, the dissolution physical development action in the exposed areas is suppressed during physical development, and as a result, a pattern is formed in which the reflectance of the physical development nucleus layer changes in a pattern.

FIG. 6 shows a pattern in which the reflectance changes in the physical development nucleus layer as described above.

That is, No. 10 indicates that the metal compound-containing layer is not subjected to physical development;
11 shows a weakly reflective part of the physical development nucleus layer after being removed, and 11 shows a highly reflective part.

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

Hereinafter, the present invention will be explained in detail according to examples, but the real-axis embodiment of the present invention is not limited thereby.

Example-1 A 2.0 aqueous solution of acid-treated ossein gelatin (electrification point 7.5) was coated on a 1.6 tm thick glass plate with excellent smoothness using a wire bar and solidified with cold air. After setting, the gelatin layer was air-dried for 90 minutes to obtain a gelatin layer with a dry thickness of 0.2 μm.

A thin film of Ag with a thickness of about 100λ was provided on the gelatin layer by vacuum evaporation.

When the sample is left in the air for several hours, Ag atoms diffuse into the gelatin layer, the surface becomes non-conducting, and the reflectivity is lost. A fine-grain silver iodo-bromide gelatin emulsion (more than 3 moles of silver iodide, average grain size 0.05 am) was coated as a metal compound on the upper layer of this physical 'fA image nuclear image in an amount of coated silver of 3 g/-. A sample was obtained.

This sample'f! - After developing for 1 minute at a conductivity of 30°C with a developer having the following composition without exposure, Na25O
The silver iodobromide gelatin emulsion layer was peeled off by immersing it in a 20-liter aqueous solution of II for 1 minute and washing with wet water at 37°C.

[Developer]

As a result, the reflectance of the recording medium through the glass substrate is 6.
It was 50% at 33 nm 4C.

1.4μ for the obtained recording medium sample according to the present invention.
He − with a recording surface output of 10 mW and a beam diameter of m diameter.
The Ns laser beam was scanned at a scanning speed of 5.2 m/see using a rotating mirror, and 500 ng was transmitted to the acousto-optic modulator.
Writing and recording was performed by applying a pulse signal to form bits. As a result, a recording surface with a remarkable difference in reflectance was obtained, good signal contrast was obtained, and optical reading was easily possible. The threshold energy for writing at this time was about 50 mJ/-, and the recording/reproducing S/N ratio was 50 dB or more.

Example 2 A sample according to the present invention having reflective properties with metallic luster was obtained in the same manner as in Example 1 except that the order of applying the gelatin layer and depositing Ag was changed. The reflectance through the glass plate at this time was 55 at 633 nm. 8 Recording and reproduction were performed on the obtained recording medium sample according to the present invention in the same manner as in Example-1, and the same good results as in Example-1 were obtained.

Example 3 A recording medium sample according to the present invention was prepared in the same manner as in Example 1, except that polymethyl methacrylate with a thickness of 1.2 m was used as the support. Recording and reading were performed.

As a result, the threshold energy for writing (recording) is 50
mJ/cd, and the recording/reproduction S/N ratio was 50 dB or more.

Example-4 Phot for each sample prepared in Examples 1 to 3 above.

5ensito Meter Model KS-78
(manufactured by Jt! Iki Kogyo Co., Ltd.), physical development was performed in the same manner as in Example 1, except that exposure was performed from the silver iodobromide gelatin emulsion layer side through the pattern at an exposure dose of 200 CMS. The reflectance of the exposed area decreased, and a silver mirror could be formed in a pattern.

This is thought to be because the formation of silver mirrors is suppressed in the exposed areas, and chemical development to form blackened silver proceeds. An example of the reflectance at 633 nm of the sample obtained at this time is shown in Table 1.

Chapter 1 Table

[Brief explanation of the drawing]

tIIJ1 is a cross-sectional view of the precursor [1] of the optical information recording medium of the present invention, FIG. 2 is a cross-sectional view of the precursor [2] of the optical information recording medium of the present invention, and FIGS. FIG. 4 is a sectional view of the optical information recording medium of the present invention before and after recording,
5 and 6 are cross-sectional views of the optical information recording medium according to the present invention in which the photosensitive metal compound-containing layer has been subjected to pattern exposure. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Organic layer, 3...Metal or semimetal or metal compound thin film, 4...Metal, semimetal or metal compound particle, 5...Physical development nucleus having reflective properties Layer, 6...Laser light, γ...Pit, 8.
... Pattern, 9... Exposure, 10... Low reflective part, 11... High reflective part, 12... Photosensitive metal compound-containing layer. (1 other person) Figure 1 (A) (B) Figure 2 (A) (B) Figure 3 (A) (B) Figure 4 (A) (B), Figure R6

Claims (1)

[Claims] 11) In an optical information recording medium that has a recording layer on a substrate and records and reproduces information using a high-density energy beam, the physical development of a physical development nucleus layer that forms the recording layer 1. An optical information recording medium characterized in that development nuclei are made of a metal or metalloid diffused into a layer containing an organic substance. (2) The optical information recording medium according to claim 1, wherein the metal atom is an Ag atom. (3) The optical information recording medium according to claim 1, wherein the organic substance is gelatin.