JPS61108591A - Photothermal conversion type recording medium - Google Patents

Abstract

PURPOSE:To convert light to thermal energy by effectively absorbing said light and to enable high density recording and optical reproduction, by containing a specific azulenium salt compound. CONSTITUTION:A photothermal conversion type recording medium is obtained by forming a thin film 2 containing an azulenium salt compound to a substrate. The thin film 2 is formed by the vacuum vapor deposition of the azulenium salt compound represented by general formula [I] or coating a solution prepared by dissolving said compound in a solvent. The content of the azulenium salt compound is 0.1-99wt% in the thin film 2 and the thickness of said from 2 is set to 10mum or less. A pit 5 is formed by irradiating or contacting the thin film 2 with electromagnetic radiation 4. The scanning of low output laser is applied to the pit formed part and a pit non-formed part along a track and the reflectivity difference thereof is read by a photodetector.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a photothermal conversion recording medium that records and reproduces information at a high density by using a photothermal conversion effect using a laser or the like. The present invention relates to a photothermal conversion recording medium that effectively absorbs light with wavelengths in the visible and near infrared regions, converts it into thermal energy, and enables high-density recording and optical reproduction.

[Prior Art] A photothermal conversion recording medium used in optical disk technology consists of optically detectable small (for example, about IJL) pits formed in a thin photothermal conversion recording layer provided on a substrate in a spiral or circular track. It is possible to record high-density information in the form of To write information on such a disk, a focused laser beam is scanned over the surface of the laser-sensitive layer, and only the surface irradiated with this laser beam forms pits, and these pits are formed in the form of a spiral or circular track. do. The laser sensitive layer can absorb laser energy to form optically detectable pits. For example, in the heat mode recording method, the laser sensitive layer absorbs the Geezer energy irradiated, converts it into thermal energy, and forms small recesses (pits) at that location through evaporation or deformation, or optically have a difference in degree of oxidation, difference in reflectance, or difference in concentration caused by a chemical change that can be detected by
Can form pits.

The information recorded on this optical disc is detected by scanning a laser along a track and reading optical changes in areas where pits are formed and areas where pits are not formed.

A laser is scanned along the track and the energy reflected by the disk is monitored by a photodetector. When no pits are formed, the output of the photodetector decreases, while when pits are formed, the laser beam is sufficiently reflected by the underlying reflective surface and the output of the photodetector increases.

As a recording medium used for such optical discs.

Up to now, methods have been proposed that mainly use inorganic materials such as metal thin films such as aluminum vapor-deposited films, bismuth thin films, tellurium oxide thin films, and chalcogenide amorphous glass films.

On the other hand, a liquid crystal element that can use a photothermal conversion recording method can form an optical image corresponding to an optical signal generated from a laser or the like.

Conventionally, a liquid crystal element is prepared in which a mixed liquid crystal of nematic liquid crystal and cholesteric liquid crystal with negative dielectric anisotropy ′ or smectic liquid crystal with positive dielectric anisotropy is arranged between two glass substrates. When an element is irradiated with a laser beam, etc., that area generates thermal energy locally,
heated to the intropic phase. Thereafter, rapid cooling forms a liquid crystal phase with a random orientation different from the initial uniform orientation. As a result, light scattering occurs at the location where the laser beam is irradiated, resulting in a difference in optical characteristics between the liquid crystal phase in the background region, which is in a uniformly aligned state.

This type of liquid crystal element can also erase an optical image formed by laser writing using the method described above. In other words, electrodes are provided on each of the two substrates that make up the liquid crystal element, and by heating the entire liquid crystal element with a laser beam and another heat source (for example, a heater), the liquid crystal phase is heated to the introvic phase. However, the optical image previously formed by writing can be erased by cooling until a homeotropic structure is formed in the case of a smectic liquid crystal, or a grandeuran structure in the case of a cholesteric-nematic liquid crystal.

A liquid crystal device using such a photothermal conversion recording method does not require a matrix electrode structure to form pixels, and can form an image pattern simply by scanning optical signals converted from electrical signals. It has the advantage of being available on screen. However, when using laser light,
It has the drawback that the efficiency of absorbing laser light and converting it into thermal energy is not sufficient, and that sufficient writing cannot be performed even if an optical signal is scanned. Therefore, in the past, for example, “5ociety of Information Di
spray International Sympo
Digest of Technical
Paper” P, P34-49.172-187.2
38-253 (1982), a guest-host type photothermal conversion recording type liquid crystal element in which a black dye is mixed into a smectic liquid crystal has been proposed.

Incidentally, in recent years, semiconductor lasers have been developed that are small, low-cost, and capable of direct modulation.
What is the oscillation wavelength of this laser? It often has a wavelength of OOn+w or more, and generally has a lower laser light power than gas lasers such as argon lasers and helium-neon lasers.

Therefore, when performing photothermal conversion recording using such a semiconductor laser, it is effective that the absorption characteristic of the laser sensitive layer has an absorption peak on the long wavelength side (generally in the region of 700 nm to 850 nm).

However, conventional photothermal conversion recording media do not have sufficient efficiency in absorbing laser light and converting it into thermal energy. , has the disadvantage that the laser utilization rate is low and high sensitivity characteristics cannot be obtained due to the high reflectance of laser light, and the sensitive wavelength range is 7Q.
Setting the thickness to Onm or more has the disadvantage of complicating the layer structure of the laser sensitive layer. For this reason, in recent years organic materials that can change substances with light energy in a relatively long wavelength range have been developed.
For example, US Pat. No. 431
No. 5983, r Re5each Disclosure
eJ 2051? (1981, 5), rJ, and Vac.

Sal, Technol, 18'(1), Ja
n,/Feb, 1981. The organic compound containing the square lylium dye disclosed in P2O3 to P109 is 70
It is known that it is sensitive to lasers of 0 na+ or higher.

However, organic compounds generally have problems such as their absorption characteristics becoming more unstable in the longer wavelength region and being easily decomposed by a slight temperature rise.

On the other hand, when a guest-host type photothermal conversion recording type liquid crystal element uses a semiconductor laser as described above, the power is low, so the efficiency of absorbing laser light and converting it into thermal energy is not sufficient, and it is It has the disadvantage of requiring low power or low speed optical signal scanning. In addition, the liquid crystal element using the black dye described above has a drawback in that a white image pattern is formed in a black background, which does not provide good display from an ergonomic point of view.

[Problem to be solved by the invention 1 As mentioned above, it is necessary to satisfy various characteristics required of photothermal conversion recording media used as optical disks and liquid crystal elements, so it is not necessarily possible to fully satisfy them in terms of practicality. At present, it cannot be said that a photothermal conversion recording medium has been developed.

Therefore, a first object of the present invention is to provide a new and useful photothermal conversion recording medium.

The second object of the present invention is to provide a photothermal device that has absorption characteristics in the visible and near-infrared wavelengths, effectively absorbs light and converts it into thermal energy, and enables high-density recording and optical reproduction. The objective is to provide a conversion recording medium.

A third object of the present invention is to provide a thermally stable photothermal conversion recording medium that eliminates the above-mentioned drawbacks.

A fourth object of the present invention is to provide a novel photothermal conversion recording medium for optical discs.

A fifth object of the present invention is to provide a photothermal conversion recording medium for optical disks that is highly sensitive at wavelengths in the visible and near infrared regions and has a sufficient S/N ratio.

A sixth object of the present invention is to provide a liquid crystal element that can use a novel photothermal conversion recording method.

A seventh object of the present invention is to provide a liquid crystal device using a photothermal conversion recording method that can form an optical image pattern in response to scanning of an optical signal from an optical signal generator using a laser oscillator. .

[Means for Solving the Problems] and [Operation] The objects of the present invention are achieved by a photothermal conversion recording medium containing an azulenium salt compound represented by the following general formula [I].

General Formula [I] In General Formula [I], R1 to R7 represent a hydrogen atom, a halogen atom (chlorine atom, bromine atom, iodine atom) or a monovalent organic residue. Monovalent organic residues can be selected from a wide variety of groups, but in particular alkyl groups (methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-amyl, n-hexyl, n-octyl, 2-ethylhexyl, t-octyl, etc.), alkoxy groups (methoxy, ethoxy, propoxy, butoxy, etc.), substituted or unsubstituted aryl groups (phenyl, tolyl, xylyl, ethylphenyl, methoxyphenyl,
ethoxyphenyl, chlorophenyl, nitrophenyl,
dimethylaminophenyl, α-naphthyl, β-naphthyl, etc.), substituted or unsubstituted heterocyclic groups (pyridyl, quinolyl, carbazolyl, furyl, chenyl, pyrazolyl, etc.), substituted or unsubstituted 7ralkyl groups (benzyl, 2- Phenylethyl, 2-phenyl-1-methylethyl, bromobenzyl, 2-bromophenylethyl, methylbenzyl, methoxybenzyl, nitrobenzyl), acyl) group (7'''ti''・pu''ye-r=tv・7 Chi9″・
Papalyl, benzoyl, trioyl, naphthoyl, phthaloyl, furoyl, etc.), substituted or unsubstituted amino groups (amino, dimethylamino, diethylamino, dipropylamino, acetylamino, benzoylamino, etc.), substituted or unsubstituted styryl groups (styryl), , dimethylaminostyryl, diethylaminostyryl, dipropylaminostyryl, methoxystyryl, ethoxystyryl, methylstyryl, etc.), nitro group, hydroxy group,
Mercapto group, thioether group, carboxylic acid, carboxylic acid ester, carboxylic acid amide, cyano group, substituted or unsubstituted arylazo group (phenylazo, α-naphthylazo, β-naphthylazo, dimethylaminophenylazo, chlorophenylazo, nitrophenylazo, methoxy phenylazo, tolylazo, etc.). or.

R, and R2, R2 and R3, R3 and R4, R4 and R5, R
, and R6 and R6 and R7, at least one combination may form a substituted or unsubstituted fused ring, and the fused ring is a 5-, 6-, or 7-membered fused ring, Mention may be made of aromatic rings, heterocycles or rings formed by aliphatic chains.

R8, R9 and R are hydrogen atoms, alkyl groups (methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-amyl, n-hexyl, n-octyl, 2-ethylhexyl, E- octyl, nonyl, dodecyl, etc.), alkoxy groups (methoxy, ethoxy, propoxy, but, toxoxy, amyloxy, hexoxy, octoxy, etc.), substituted or unsubstituted aryl groups (phenyl, tolyl, xylyl, ethylphenyl, methoxyphenyl, chlorophenyl) , nitrophenyl, dimethylaminophenyl, dibenzylaminophenyl, α-naphthyl, β-naphthyl, etc.), substituted or unsubstituted styryl group, or substituted or unsubstituted 4-phenyl-1,3-
Butadienyl group (styryl, methoxystyryl, dimethoxystyryl, ethoxystyryl, jetoxystyryl, dimethylaminostyryl, diethylaminostyryl,
4-phenyl-1,3-butadienyl, 4-(p-dimethylaminophenyl)-1,3-butadienyl, 4-(
p-diethylaminophenyl)-1,3-butadienyl, etc. ) or C represents a substituted or unsubstituted heterocyclic group (3-carbazolyl, 8-methyl-3-carbazolyl, 8-ethyl-3-carbazolyl, 8-carbazolyl, etc.), and R and R9 or R9 and R1 ° may be combined to form a substituted or unsubstituted benzene ring.

R represents a hydrogen atom, a nitro group, a cyano group, an alkyl group (methyl, ethyl, propyl, butyl, etc.) or an aryl group (phenyl, tolyl, xylyl, etc.).

Z represents a sulfur atom, an oxygen atom or a selenium atom.

A represents an atom necessary to complete substituted or unsubstituted pyran, thiopyran, selenapyran, benzopyran, benzothiopyran, benzoselenapyran, naphthopyran, naphthothiopyran or naphthoselenapyran.

e Z represents an anion residue, and specific examples of Z are:
Berchlorate, fluoroporate, sulfoacetate, iodide, chloride, bromide, p-toluenesulfonate, alkylsulfonate, alkyldisulfonate, penzenedisulfonate, halosulfonate, viclate, tetracyanoethylene anion, tetracyanoquinodimethane anion, etc. Represents an anionic residue.

n represents an integer of 0.1 or 2; n represents an integer of 0 or 1;

Specific examples of the azulenium salt compounds used in the present invention are listed below.

"l'
N (J=Kono
Oath η Engineering χ Rohero Ill
I
I+=
= b
Q~
~ ＼ Engineering Me 1? ■ = B To the entrance The 7 durenium salt compound of the present invention has the following general formula [] General formula [■]: (wherein, R1-R7, R11 and m are the above general formula [
I] and the same meaning as) and the formyl azulene compound represented by the general formula [I General formula [T! i]: ...[+1] (in the formula, R8* R9+ R1o* A + X +
Z o and n can be obtained by reacting a compound represented by the above general formula [same definition as I1] in a solvent.

- an azulenium compound represented by the formula [I],
The compound where 厘=O is an azulene compound represented by the general formula [I9']]: (wherein R1-R7 has the same meaning as the general formula [I]) and the general formula [V]4"-ゝv]: (In the formula, R8 + 19 + R1゜, A, X, and n
It can also be easily obtained by reacting an aldehyde compound represented by the general formula [I] in an appropriate solvent in the presence of a strong acid.

A wide range of organic solvents can be used, but in particular alcohols such as ethanol, propatool and butanol, nitriles such as acetonitrile, ketones such as methyl ethyl ketone, nitro compounds such as nitrobenzene, and halogens such as tetrachloroethane. Hydrocarbons, organic acids such as acetic acid, and acid anhydrides such as acetic anhydride are used.

Next, a method for synthesizing typical compounds among the heptadurenium salt compounds of the present invention will be described.

9th Emperor': Compound No., (1) 1-formyl-3,8-dimethyl-5-isopropyl, 7fyy, 1°5'22・4-'niaz:jlz
-5, 8, 7, 8+) 2.58 g of 5h drobenzobilylium verchlorate in 50 ml of acetic anhydride, 80-80
The reaction was carried out for 2 hours at a liquid temperature of °C. After cooling, the precipitated crystals were boiled and washed with glacial acetic acid, water, and ethanol in this order.
Dry. As a result, 3.35 g of an azulenium salt compound of compound N001 was obtained.

Yield: 85% Elemental analysis: Molecular formula C37H,, C 05 calculated value (z) Analysis value (z) C74,8874,57 H5,946,03 C text 5.98 5.83 Synthesis example 2: Compound No. (8) 2.4 g of 1-chloro-4,8,8-)limethylazulene
and 2,4-diphenyl-tetrahydrobenzopyrrolo-8
-3.89 g of ω-aldehyde was added to 15 g of tetrahydrofuran.
Dissolve at 0°C and add 4 m of 70% perchloric acid at a liquid temperature of 2″5°C.
fL was added and stirred at the same temperature for 6 hours. The precipitate was separated in a furnace, washed with tetrahydrofuran, water, and tetrahydrofuran in this order, and dried. As a result, the compound [No, (9)
3.88 g of 7 durenium salt was obtained.

Yield: 55% Elemental analysis: Molecular formula C3, H3, C1205 Calculated value (X) Analytical value (X) CBi2.88 1313.73H5,045
, 18 C111, 7911, 84 The photothermal conversion recording medium of the present invention can be used for optical disk recording.For example, a thin film 2 containing the above-mentioned 7-durenium salt compound is formed on a substrate 1 as shown in FIG. The thin film 2 can be formed by vacuum evaporation of the azulenium salt compound represented by the above-mentioned general formula [I], or can be formed by a coating containing the above-mentioned azulenium salt compound in a suitable solvent. It can also be formed by applying an industrial solution. When forming a film by coating, the above-mentioned 7 durenium salt compound may be contained in a solvent in a dispersed state or in an amorphous state. As a suitable binder, a resin can be contained as a binder.
You can choose from a wide range of resins, including nitrocellulose, cellulose phosphate, cellulose [8],
Cellulose acetate, cellulose propionate, cellulose acetate 1. Cellulose esters such as cellulose myristate, cellulose palmitate, cellulose acetate/propionate, cellulose acetate/acetate, cellulose ethers such as methyl cellulose, ethyl cellulose, propyl cellulose, butyl cellulose, polystyrene,
Vinyl resins such as polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyvinylpyrrolidone, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, etc. copolymer resins, polymethyl methacrylate, polymethyl acrylate, polybutyl acrylate, polyacrylic resin,
Acrylic resins such as polymethacrylic acid, polyacrylamide, and polyacrylonitrile; polyesters such as polyethylene terephthalate; ethylene dioxy-3,3'-phenylene thiocarbonate), poly(
4,4''-isopropylidene diphenylene carbonate coated terephthalate), poly(4,4'-isopropylidene diphenylene carbonate), poly(4,4'-
Polyarylate resins such as 5ec-butylidene diphenylene carbonate), poly(4,4'-isopropylidene diphenylene carbonate block-oxyethylene), polyamides, polyimides, epoxy resins, phenolic resins, polyethylene Polyolefins such as , polypropylene, and chlorinated polyethylene can be used.

The organic solvent that can be used during coating varies depending on the type of binder and whether the above-mentioned compound is contained in the binder in a single dispersed state or in an amorphous state, but in general, methanol is used. , 7''' alcohols such as ethanol and isopropanol, acetone, methyl ethyl ketone, and alcohol.

Ketones such as clohexanone, amides such as N,N-dimethylformamide, N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, methyl acetate, ethyl acetate , esters such as butyl acetate, aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichlorethicine, or benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene Aromatics such as, etc. can be used.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out using a coating method such as a bouillon coating method, a blade coating method, a roller coating method, or a curtain coating method.

When forming thin Fs2 with a binder, the above-mentioned [
The content of the azulenium salt compound in the thin film 2 is 0.1 to 38% by weight, preferably 40 to 80% by weight. In addition, the dry film thickness or vapor deposited film thickness of thin Fs2 is 10
It is less than a micron, preferably less than 2 microns.

As the substrate 1, plastics such as polyester, acrylic resin, polyolefin resin, phenol resin, epoxy resin, polyamide, and polyimide, glass, or metals can be used.

The photothermal conversion recording medium of the present invention is obtained by forming the aforementioned thin film 2 (electromagnetic radiation sensitive layer) on the substrate l used as a support, but various auxiliary layers may be provided. A substrate having a surface coating made of an inorganic or organic material for the purpose of adjusting the thermal constant can be used. In addition, a protective layer made of a transparent material can be provided on the thin film 2, and this protective layer is effective in preventing mechanical damage, and by forming it with an appropriate thickness, it can reduce reflection. Since it can be used as a preventive film,
It is also effective in improving sensitivity. Further, as shown in FIG. 2, a reflection N3 can be provided between the thin film 2 and the base 1. This reflective layer 3 can be a vapor deposited layer or a laminate layer of a reflective metal such as aluminum, silver, or chromium.

Further, the photothermal conversion recording medium of the present invention is disclosed in Japanese Patent Application No. 57-723.
It is possible to form a pregroove having a function such as a track guide groove or an address designation groove as described in the specification of No. 74.

' The photothermal conversion recording medium of the present invention, as shown in FIG. Helium-neon gas laser (oscillation wavelength = 832.8n)
m) In addition, the pits 5 can be formed by irradiating or contacting with various short pulse light emitting lamps such as lasers and xenon flash lamps having oscillation wavelengths from the visible region to the infrared region, infrared lamp light, or heaters.

This bit forming area has a reflectance different from that of the bit-free area, so a bit is formed by, for example, scanning electron radiation along the track, and the above-mentioned track is formed between the pit-forming area and the pit-free area. It is possible to scan a low-power laser along the surface and read the difference in reflectance with a photodetector.

In another specific example of the present invention, the liquid crystal element can be applied as a photothermal conversion recording type liquid crystal element. For example, as shown in FIG. , the liquid crystal composition 108 has the general formula [I
] Smectic liquid crystal is suitable as the liquid crystal used in the liquid crystal element applied to the photothermal conversion recording medium of the present invention, and in particular has positive dielectric anisotropy. Smectic liquid crystal A phase or C phase is suitable. Such smectic liquid crystals are arranged in the smectic phase of a homeotropic structure until they are locally heated by a laser beam, and as the temperature increases, the phase changes from the smectic phase of the homeotropic structure to the nematic phase to the isotropic phase. Next, when the phase is changed from the intropic phase to the smectic phase under rapid cooling, a smectic phase with a focal conic structure having light scattering properties is formed.

Therefore, when the smectic phase in the liquid crystal element is locally heated to the introbic phase by irradiation with a laser beam, and then rapidly cooled, the area becomes a smectic phase with a focal conic structure, and this state has light scattering properties, so A still image pattern can be formed by scanning an optical signal with a laser beam.

Compounds capable of forming a smectic phase having positive dielectric anisotropy to be used in the liquid crystal element of the present invention include, for example,
Compounds described in JP-A No. 8-150030, JP-A-57-40429, JP-A-57-51779, etc. can be used.

The azulenium salt compound represented by the aforementioned general formula [I] can be contained in the liquid crystal composition 108 in an amount of 0.1% by weight or more, preferably in the range of 1% to 3% by weight based on the liquid crystal.

Furthermore, the liquid crystal element of the present invention can also use a mixed liquid crystal of smectic liquid crystal and cholesteric liquid crystal having positive dielectric anisotropy. Cholesteric liquid crystal is liquid crystal composition 1
It is suitable for the content in the range of 0.5% by weight to 15% by weight, preferably in the range of 1% to 5% by weight.

Cholesteric liquid crystals that can be used in the present invention include cholesteryl chloride, cholesteryl bromide, cholesteryl iodite, cholesteryl nitrate, cholesteryl chloroticaate, cholesteryl butyrate, cholesteryl caprate, cholesteryl oleate, cholesteryl oleate, cholesteryl laurate, Cholesteryl compounds such as cholesteryl myristate, cholesteryl heptyl carbamate, cholesteryl decyl ether, cholesteryl lauryl ether, and cholesteryl oleyl ether are synthesized. .

A liquid crystal element using such a mixed liquid crystal causes a phase change from a homeotropic smectic phase to an intropic phase by local heating with a laser beam, and when this is rapidly cooled, a smectic phase with a focal conic structure is formed as described above. be able to.

The liquid crystal element recorded by the above-mentioned method uses liquid crystal composition 1.
After heating the entire surface of 08 with a heater to change the phase to an intropic phase, electrodes 103 are provided on substrates 101 and 102 (for example, plastic plates such as transparent glass plates and acrylic plates) constituting the liquid crystal element. By applying a suitable direct current or alternating current between and 104 and slow cooling, a phase change can be caused from an intropic phase to a nematic phase to a smectic phase. At this time, since the liquid crystal in the nematic phase has positive dielectric anisotropy, the nematic liquid crystal is aligned in the direction of the electric field, and when it is further cooled, a smectic A phase or C phase with a homeotropic structure is formed, and the written image is The pattern will be erased. Electrode 103
and 104 are generally obtained by a transparent conductive film of indium oxide, tin oxide, or ITO (Indium TinOxide), and if necessary, by a metal conductive film of aluminum, chromium, silver, nickel, or the like. These electrodes 103 and 104 are desirably coated over the entire surface of the substrates 101 and 102, and do not necessarily have to have a predetermined pattern shape or matrix electrode structure. Alternatively, it is also possible to design a matrix electrode structure.

The liquid crystal element of the present invention has alignment control films 108 and 10 made of an insulating material coating on the electrodes 103 and 104, respectively.
7 can be provided. These alignment control films 108 and 10
No. 7 has a surface structure that allows the alignment direction of the liquid crystal composition 108 that contacts these critical surfaces to be controlled to a desired state. Also, this orientation control? ! 10B and 107 also function as insulating films that can prevent generation of current flowing through the liquid crystal composition 108. This type of alignment control films 1013 and 107 are made of, for example, -silicon oxide, silicon dioxide,
aluminum oxide, zirconia, magnesium fluoride,
Cerium oxide, cerium fluoride, silicon nitride, silicon carbide, boron nitride, polyvinyl alcohol, polyimide, polyamideimide, polyesterimide, polyparaxylerin, polyester, polycarbonate, poly and nylacetal, polyvinyl chloride, polyamide , polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin, organosiloxane, polyfluoroethylene, and other insulating materials can be applied by vapor deposition, dip coating,
It can be obtained by forming a film using a spinner coating method or a spray coating method.

The alignment control films 10B and 107 homogeneously align the liquid crystal composition 108 by rubbing the surface with cloth, paper, velvet, etc., or by using an oblique vapor deposition method when forming the film, depending on a predetermined writing method. A silane compound that can have a surface structure or has a perfluoroalkyl group on its surface, for example, as described in JP-A-50-31315Q, JP-A-50-50
By treating with a compound such as an alkyltrialkoxysilane described in Japanese Patent Publication No. 947, or a tetraalkoxysilane described in JP-A-50-83955, a surface structure for homeotropically aligning the liquid crystal composition 108 can be obtained. You can have it.

The optimum film thickness for the orientation between @Wlttoe and 107 varies depending on the type of insulating material used, but is generally in the range of 100 A to 1, preferably 500 A to 200 A.
It is suitable to set the thickness within the OA range, and it is also desirable to set the film thickness so that the alignment control films 10Ei and 107 also function as antireflection films.

Further, the liquid crystal element of the present invention forms the above-mentioned still image by irradiating the laser beam 110 from the rear direction as shown in the figure, and uses observation light 108 such as natural light, halogen lamp light, xenon lamp light, fluorescent lamp light, etc. from the front direction. The above-mentioned still image can be observed by making the light beam incident on the element and using this light beam as reflected light from the cold mirror 105. This cold mirror 105 generally has sufficiently high reflectance for visible light and high transmittance for long wavelength light of 800 nm or more. in particular,
Ge/MgFz (1/4 person) /Ce02 (1
/4 people) 7MgF2 (l/4 people) /CeO□ (
A multilayer film consisting of 1 layer is known. However, in the present invention, the use of cold mirror 105 can also be omitted. In addition, the device of the present invention connects a cold filter (not shown) to the electrode 103 and orientation control I! It can also be provided between 10B. This cold filter has a sufficiently high transmittance for visible light and a sufficiently high reflectance for long wavelength light.

[Examples] Hereinafter, the present invention will be explained in detail according to Examples, but the present invention is not limited thereto.

Example 1 12 parts by weight of nitrocellulose solution (manufactured by Daicel Chemical Industries, Ltd.; overless lacquer: 25% by weight nitrocellulose solution in methyl ethyl ketone), the aforementioned compound No.
3 parts by weight of the compound 1) and 70 parts by weight of methyl ethyl ketone were thoroughly mixed in a ball mill. This mixed solution was applied onto a disc-shaped aluminum vapor-deposited glass plate with a diameter of 30 cm by a spinner coating method, and then dried to a 0.05 mm diameter.
A recording layer of 8 g/m2 was obtained.

The optical disc recording medium thus created was mounted on a turntable, and the turntable was rotated by a motor at 11,000 rpm.
A gallium-aluminum-arsenide semiconductor laser (oscillation wavelength 780 nm) with an output of 5 MHz and a pulse width of 8 MHz focused to a spot size of 1.0 microns while giving a rotation of
Recording was carried out by scanning the recording layer surface in the form of a track.

When the surface of this recorded optical disc was observed using a scanning electron microscope, clear pits were observed. Furthermore, when a low-output gallium-aluminum-arsenide semiconductor laser was incident on this optical disk and reflected light was detected, a waveform with a sufficient S/N ratio was obtained.

In addition, in order to measure the durability stability over time after recording, the recorded recording medium was left in a forced environment of a temperature of 35°C and a relative humidity of 85% for 240 hours, and then the surface of the recorded recording medium was was observed under a microscope in the same manner as described above, and pits similar to those observed before the durability test were observed. Furthermore, when a low-output gallium-arsenide-aluminum semiconductor laser was incident on the recording medium on which this j' had been recorded and which had undergone a durability test, and the reflected light was detected, a waveform with a sufficiently high S/N ratio was obtained. Ta.

, Example 2 The above-mentioned compound No. (5) was coated on a disk-shaped aluminum vapor-deposited glass plate with a diameter of 30 cm using a spinner coating method in the same manner as in Example 1 to obtain a coating composition of 0.13.
An optical disc recording medium having a recording layer of g/m2 was prepared.

When information was recorded on this optical disk recording medium in the same manner as in Example 1 and then reproduced, a waveform with a sufficient S/N ratio was observed. Further, when the surface of the recording layer after information was written was observed with a scanning electron microscope, clear pits were found to have been formed. Further, a durability test after recording was carried out in the same manner as in Example 1, and similar results were obtained.

Example 3 The above-mentioned compound No. (10) was applied to a disc-shaped aluminum vapor-deposited glass having a diameter of 30 cm in the same manner as in Example 1.
- An optical disk recording medium having a recording layer of 0.13 g/s' was prepared by coating on a substrate by a spinner coating method.

When information was stored on this optical disk recording medium in the same manner as in Example 1 and then reproduced, a waveform with a sufficient S/N ratio was observed. Further, when the surface of the recording layer after information was written was observed with a scanning electron microscope, clear pits were found to have been formed.

Further, a durability test after recording was carried out in the same manner as in Example 1, and similar results were obtained.

Example 4 The above-mentioned compound No. (12) was coated on a disk-shaped aluminum vapor-deposited glass plate with a diameter of 30 cm by spinner coating method in the same manner as in Example 1 to give a coating of 0.8 cm.
An optical disc recording medium having a recording layer of g/m2 was prepared.

When information was stored on this optical disk recording medium in the same manner as in Example 1 and then reproduced, a waveform with a sufficient S/N ratio was observed. Further, when the surface of the recording layer after information was written was observed with a scanning electron microscope, clear pits were found to have been formed.

Further, a durability test after recording was carried out in the same manner as in Example 1, and similar results were obtained.

Example 5 The above compound No. (17) was coated on a disk-shaped aluminum vapor-deposited glass plate with a diameter of 30 cm by spinner coating method in the same manner as in Example 1.
An optical disc recording medium having a recording layer of 8 g/+a2 was prepared.

When information was stored on this optical disk recording medium in the same manner as in Example 1 and then reproduced, a waveform with a sufficient S/N ratio was observed. Furthermore, when the surface of the recording layer after information was written was observed using a scanning electron microscope, clear pits were found to have been formed.

Further, a durability test after recording was carried out in the same manner as in Example 1, and similar results were obtained.

Example 6 The above-mentioned compound No. (20) was coated on a disc-shaped aluminum vapor-deposited glass plate with a diameter of 30 cm using a spinner coating method in the same manner as in Example 1 to give a coating composition of 0.8 cm.
An optical disc recording medium having a recording layer of g/layer 2 was prepared.

When information was stored on this optical disk recording medium in the same manner as in Example 1 and then reproduced, a waveform with a sufficient S/N ratio was observed. Further, when the surface of the recording layer after information was written was observed with a scanning electron microscope, clear pits were found to have been formed.

Further, a durability test after recording was carried out in the same manner as in Example 1, and similar results were obtained.

Example 7 The above-mentioned compound No. (22) was coated on a disc-shaped aluminum vapor-deposited glass plate with a diameter of 30 cm using a spinner coating method in the same manner as in Example 1 to obtain a coating composition of 0.8 cm.
An optical disc recording medium having a recording layer of g/m2 was prepared.

When information was stored on this optical disk recording medium in the same manner as in Example 1 and then reproduced, a waveform with a sufficient S/N ratio was observed. Further, when the surface of the recording layer after information was written was observed with a scanning electron microscope, clear pits were found to have been formed.

1 In addition, a durability test after recording was carried out in the same manner as in Example 1, and similar results were obtained.

Example 8 500 μg of the above compound No. (2) was put into a molybdenum port for vapor deposition, and after evacuated to below I x 10” mmHg, it was vapor deposited on an aluminum vapor-deposited glass plate.During the vapor deposition, the pressure in the vacuum chamber was kept constant. A vapor deposited film of 0.2 microns was formed while controlling the heater so that the temperature did not rise above 10'lmmHg.

When information was stored in the optical disc recording medium thus prepared in the same manner as in Example 1, clear pits similar to those in Example 1 were observed, and information was reproduced in the same manner as in Example 1. At this time, a waveform with a sufficient S/N ratio was observed.

Example 9 FIG. 5 shows an example in which a display pattern was formed using the liquid crystal element of the present invention.

Among the compounds represented by the above-mentioned general formula [I], compound No.
-cyanooctylbiphenyl; positive dielectric device - having 5-isotropy) was dissolved in a proportion of 2% by weight. At this time, the liquid crystal composition is heated until it becomes an isotropic phase, the above-mentioned compound is added, and this liquid is injected into a cell whose inner wall surface has been subjected to homeotropic alignment treatment. A smectic phase liquid crystal with a tropic structure was formed.

The laser oscillator 202 that emits the laser beam used to write an image on the liquid crystal cell 201 can be selected from those with wavelengths that correspond to the absorption efficiency of the above-mentioned compounds contained in the liquid crystal. A long wavelength laser beam emitted from a neon laser, a semiconductor laser, or a YAG laser, or a short wavelength laser beam emitted from an argon laser can be used. The laser beam emitted from the laser oscillator 202 is transmitted to modulators 203, 7. ! j cut 204, Y-axis deflector 2
05, the light passes through the X-axis deflector 206, is modulated and deflected, is focused by the writing lens 208, and is irradiated from the back side of the liquid crystal element 201 via the gicroic mirror 208. The aforementioned modulator 203 and Y-axis deflector 2
05, the X-axis deflector 206 is connected to the signal source 211 via the driving amplifier 210, thereby controlling the laser beam and converting the digital electrical signal from the signal source 211 into an optical signal. An image pattern is written on the liquid crystal element 201 by this optical signal. After that, the Bertier element 2 attached to the periphery of the liquid crystal element 201 is
12 is activated by a power source 213 to bring it into a quenched state, thereby cooling the liquid crystal element 201 and forming a smectic phase with a focal conic structure, forming an image pattern in which the portions irradiated with the optical signal are in a light scattering state. It was done. At this time, the temperature of the Bertier element 212 is controlled by the temperature controller 214.

This image pattern can be observed by turning on the illumination source 215 placed in front of the liquid crystal element 201.

Next, in order to erase the image pattern described above, a transparent heater 218 (for example, an indium oxide film, a tin oxide film, an ITO film) provided on the liquid crystal element 201 is connected to a temperature controller 2.
It is heated by a heater power supply 218 via a heater power source 218 via a heater power source 218 to cause a phase change from a liquid crystal phase to an isotropic phase. After that, while applying a voltage from the AC power supply 221 between the electrodes 218 and 220 provided on the liquid crystal element 201, the liquid crystal element 201
was slowly cooled to form a smectic phase with a homeotropic structure. As a result, the written image pattern was erased.

[Effect of the invention] The effects of the present invention are listed below.

The photothermal exchange recording medium of the present invention has a thin electromagnetic radiation-sensitive layer that has a high absorption efficiency for electromagnetic radiation, and enables recording with a low energy density helium-neon gas laser or xenon flash lamp, and oscillates on the long wavelength side. It is also effective for recording using a semiconductor laser with a certain wavelength. Furthermore, the S/N ratio is high and the regeneration efficiency is good. Furthermore, the compound used in the present invention has the advantage of being extremely stable against heat.

) Furthermore, the liquid crystal element related to the photothermal conversion recording medium of the present invention can be applied as a large screen display, and can also be used in a recording method in which pits are formed by scanning an optical signal containing predetermined information along a track. It can also be applied to other optical disk systems.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are sectional views of a photothermal conversion recording medium for optical disks and discs of the present invention, respectively. FIG. 3 is an explanatory diagram showing an embodiment of the photothermal conversion recording medium. FIG. 4 is a cross-sectional view of a liquid crystal element showing an example of the photothermal conversion recording medium of the present invention. FIG. 5 shows one of the display methods using the liquid crystal element of the present invention.
It is an explanatory diagram showing an example. 2: thin film, 3: reflective layer, 4: electromagnetic radiation, 5: bit, 101, 102: substrate, 103.104: electrode, 105
: Cold Mirror, 108, 10? : alignment control film, 108: liquid crystal composition,
1013: observation light, 110: laser beam.

Claims (3)

[Claims] (1) A photothermal conversion recording medium characterized by containing an azulenium salt compound represented by the following general formula [I]. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼... [I] [However, in the general formula [I], R_1, R_2, R
_3, R_4, R_5, R_6 and R_7 are hydrogen atoms, halogen atoms, or monovalent organic residues, or R_1 and R_2, R_2 and R_3, R_3 and R_4,
R_4 and R_5, R_5 and R_6 and R_6 and R_7
represents a substituted or unsubstituted condensed ring formed by at least one combination of the following. R_8, R_9 and R_1_0 are hydrogen atoms, alkyl groups, alkoxy groups,
Substituted or unsubstituted aryl group, substituted or unsubstituted styryl group, substituted or unsubstituted 4-phenyl-1
, 3-butadienyl group or substituted or unsubstituted heterocyclic group, or R_8 and R_9, or R_9
represents a substituted or unsubstituted benzene ring formed by a combination of and R_1_0. R_1_1 represents a hydrogen atom, a nitro group, an alkyl group, or an aryl group. X represents an oxygen atom, a sulfur atom or a selenium atom. A represents an atomic group necessary to complete substituted or unsubstituted pyran, thiopyran, selenapyran, benzopyran, benzothiopyran, benzoselenapyran, naphthopyran, naphthothiopyran, or naphthoselenapyran. Z^■ is an anion residue, m is 0, 1
or an integer of 2, and n represents an integer of 0 or 1. ] (2) The photothermal conversion recording medium is formed on a substrate by the following general formula [
The light-to-heat conversion recording medium according to claim 1, comprising a coating containing an azulenium salt compound represented by [I]. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼... [I] [However, in the general formula [I], R_1, R_2, R
_3, R_4, R_5, R_6 and R_7 are hydrogen atoms, halogen atoms, or monovalent organic residues, or R_1 and R_2, R_2 and R_3, R_3 and R_4,
R_4 and R_5, R_5 and R_6 and R_6 and R_7
represents a substituted or unsubstituted condensed ring formed by at least one combination of the following. R_8, R_9 and R_1_0 are hydrogen atoms, alkyl groups, alkoxy groups,
Substituted or unsubstituted aryl group, substituted or unsubstituted styryl group, substituted or unsubstituted 4-phenyl-1
, 3-butadienyl group or substituted or unsubstituted heterocyclic group, or R_8 and R_9, or R_9
represents a substituted or unsubstituted benzene ring formed by a combination of and R_1_0. R_1_1 represents a hydrogen atom, a nitro group, an alkyl group, or an aryl group. X represents an oxygen atom, a sulfur atom or a selenium atom. A represents an atomic group necessary to complete substituted or unsubstituted pyran, thiopyran, selenapyran, benzopyran, benzothiopyran, benzoselenapyran, naphthopyran, naphthothiopyran, or naphthoselenapyran. Z^■ is an anion residue, m is 0, 1
or an integer of 2, and n represents an integer of 0 or 1. ] (3) The photothermal conversion recording medium according to claim 1, wherein the photothermal conversion recording medium comprises a liquid crystal element having a liquid crystal composition containing an azulenium salt compound represented by the following general formula [I]. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼... [I] [However, in the general formula [I], R_1, R_2, R
_3, R_4, R_5, R_6 and R_7 are hydrogen atoms, halogen atoms, or monovalent organic residues, or R_1 and R_2, R_2 and R_3, R_3 and R_4,
R_4 and R_5, R_5 and R_6 and R_6 and R_7
represents a substituted or unsubstituted condensed ring formed by at least one combination of the following. R_8, R_9 and R_1_0 are hydrogen atoms, alkyl groups, alkoxy groups,
Substituted or unsubstituted aryl group, substituted or unsubstituted styryl group, substituted or unsubstituted 4-phenyl-1
, 3-butadienyl group or substituted or unsubstituted heterocyclic group, or R_8 and R_9, or R_9
represents a substituted or unsubstituted benzene ring formed by a combination of and R_1_0. R_1_1 represents a hydrogen atom, a nitro group, an alkyl group, or an aryl group. X represents an oxygen atom, a sulfur atom or a selenium atom. A represents an atomic group necessary to complete substituted or unsubstituted pyran, thiopyran, selenapyran, benzopyran, benzothiopyran, benzoselenapyran, naphthopyran, naphthothiopyran, or naphthoselenapyran. Z^■ is an anion residue, m is 0, 1
or an integer of 2, and n represents an integer of 0 or 1. ]