JPS61228988A - Photo-thermal conversion recording medium - Google Patents

Abstract

PURPOSE:To provide a photo-thermal conversion recording medium capable of high-density recording and optical reproduction, by incorporating an azo compound comprising at least one azo group linked to a specified coupler residue. CONSTITUTION:An azo compound comprising at least one azo group linked to a coupler residue of general formula [1], wherein each of R1-R7 is hydrogen, halogen or monovalent organic residual group which may be selected from various ones, is incorporated. The azo compound is a monoazo, disazo or trisazo compound of general formula [2], wherein a is a monovalent, divalent or trivalent organic residual group having at least one conjugated double bond, and N is 1, 2 or 3. Accordingly, a novel and useful photo-thermal conversion recording medium is provided.

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 high density by utilizing the photothermal conversion effect of 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, and exchanges it into thermal energy, thereby enabling high-density recording and optical reproduction.

<Prior art> Photothermal conversion recording media used in optical disk technology are optically detectable small (for example, about 1 μ) bits formed on a thin photothermal conversion recording layer provided on a substrate in the form of a spiral or circular track. It is possible to record high-density information.

To write information on such a disc, a focused laser is scanned over the surface of the laser-sensitive layer, and only the surface irradiated by this laser beam forms bits, which are formed in the form of spirals or circular tracks. do. A laser-sensitive layer can absorb laser energy to form optically detectable bits. For example, in heat mode recording,
The laser energy irradiated to the laser sensitive layer is absorbed and converted into thermal energy, and a small recess (bit) can be formed at that location by evaporation or deformation, or a chemical change that can be optically detected at that location. It is possible to form a bit having a reflectance difference or a density difference due to the oxidation degree difference.

The information recorded on this optical disk is detected by scanning a laser along a track and reading the optical changes in areas where bits are formed and areas where no bits are formed. The energy reflected by the disk is monitored by a photodetector. When a bit is not formed, the output of the photodetector is reduced, while when a bit is formed, the laser beam is sufficiently reflected by the underlying reflective surface and the output of the photodetector is increased.

As recording media for use in such optical discs, media that mainly use inorganic materials such as metal thin films such as aluminum evaporated films, bismuth thin films, tellurium oxide thin films, and chalcogenide-based amorphous glass films have been proposed so far.

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 irradiated with laser light or the like, thermal energy is generated locally in that area, and the area is heated to the introbic 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 the entire liquid crystal element is heated with a laser beam and another heat source (for example, a heater), thereby heating the liquid crystal phase to the intropic phase. However, by cooling until a homeotropic structure is formed in the case of a smectic liquid crystal, or a glandular structure in the case of a cholesteric-nematic liquid crystal, the optical image previously formed by writing can be erased.

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 a large screen. However, when a laser beam is used, the efficiency of absorbing the laser beam and converting it into thermal energy is not sufficient, and there is a drawback that sufficient writing cannot be performed even if an optical signal is scanned. For this reason, conventionally, for example, "Society of Information Display International Symposium, Digest of Technical Papers"("5 Society of I
nformation DisplayIntern
ational Symposium, Diges
of Technical Paper”)
Pages 34-49, 172-1 & 7, 238-25
3 (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.
The oscillation wavelength of this laser often has a wavelength of 700 mm or more, and the laser light power is generally lower than that of gas lasers such as argon lasers and helium-neon lasers. Therefore, it is difficult to use such semiconductor lasers. when performing photothermal conversion recording.

It is effective for the absorption characteristics of the laser sensitive layer to have an absorption peak on the long wavelength side (generally in the region of 700 mm to 850 mm).

However, conventional photothermal conversion recording media absorb laser light and
For example, in the case of an optical disc, the photothermal conversion recording layer formed mainly of an inorganic material as described in A has a high reflectance to laser light, so the laser utilization rate is low. It has the disadvantage that high sensitivity characteristics cannot be obtained due to low sensitivity, and the sensitive wavelength range is 700 mm.
This has the disadvantage of complicating the layer structure of the laser sensitive layer. For this reason, in recent years, research has been carried out on organic compounds whose substances can be changed by light energy in a relatively long wavelength range.

For example, US Pat. No. 4,315,983 “Research Disclosure J”
sureJ), p. 20517 (May 1981) and the pyrylium dye disclosed in "Journal of Vacuum
Science and Technology J (rJ, Vac, sc
i.

Technol, J), 18 (1), January 72 issue,
It is known that the organic compound containing the square lylium dye disclosed in 1981, pages 105-109 is sensitive to lasers of 700 mm or more.

However, organic compounds generally have problems such as their absorption characteristics becoming more unstable in the longer wavelength region and being more 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 like the one mentioned above, the power is low, so the efficiency of absorbing laser light and converting it into thermal energy is not sufficient, and high power Another drawback is that it requires low-speed optical signal scanning. Further, in the liquid crystal element using the above-mentioned black dye, a white image pattern is formed in a black background, which has the disadvantage that it does not provide good display from an ergonomic point of view.

As mentioned above, it is necessary to satisfy the various characteristics required of photothermal conversion recording media used as optical disks and liquid crystal elements, so it is not necessarily the case that photothermal conversion recording media that are fully satisfactory in terms of practicality have been developed. The current situation is that it is impossible to say.

<Problems to be Solved by the Invention> Therefore, the first object of the present invention is to provide a novel and useful light-heat exchange recording medium.

The second object of the present invention is to provide a photothermal conversion system 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 goal is to provide recording media.

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 device that uses a novel photothermal conversion recording method.

A seventh object of the present invention is to provide a liquid crystal element 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. be.

[Means for Solving the Problem] and [Action] The object of the present inventor is to provide a photothermal solution containing an azo compound having at least one azo group bonded to a coupler residue represented by the following general formula [1]. This is accomplished by a conversion recording medium.

5 In the formula, 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-
7 mil, n-hexyl, n-octyl, 2-ditylhexyl, 7-octyl, etc.), alkoxy groups (methoxy,
ethoxy, propoxy, butoxy), substituted or unsubstituted 7-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 aralkyl groups ( benzyl, 2-phenylethyl, 2-phenyl-1-methylethyl, bromobenzyl, 2-bromophenylethyl, methylbenzyl, methoxybenzyl, nitrobenzyl), acyl group (acetyl,
propionyl, butyryl, valeryl, benzoyl, triooyl, naphthoyl, phthaloyl, furoyl, etc.), substituted or unsubstituted amino groups (amino, dimethylamino, etc.).

diethylamino, dipropylamino, acetylamino,
benzoylamino, etc.), substituted or unsubstituted styryl groups (styryl, dimethylaminostyryl, diethylaminostyryl, dipropylaminostyryl, methoxystyryl, ethoxystyryl, methylstyryl, etc.), nitro group, hydroxy group, methylcapto group, thioether group, carboxyl group, carboxylic acid ester, carboxylic acid amide, cyano group, substituted or unsubstituted arylazo group (
Phenylazo, α-naphthylazo, β-naphthylazo,
dimethylaminostyrylazo, chlorophenylazo, nitrophenylazo, methoxyphenylazo, tolylazo, etc.). Also, R1 and R2, R2 and R
3. Among the combinations of R3 and R4, R4 and R5, R5 and R6, and R6 and R7, at least one combination may form a substituted or unsubstituted condensed ring, and the condensed ring is 5
It is a condensed ring having 6-membered, 6-membered, or 7-membered rings, and includes aromatic rings, heterocycles, and aliphatic rings.

The azo compound used in the present invention is a monoazo compound, a disazo compound, and a trisazo compound represented by the following general formula [2].

where R1-R7 have the same definitions as defined above.

A represents monovalent, divalent, and trivalent organic residues having at least one conjugated double bond. These organic residues include hydrocarbon groups having a double bond system, Examples include a hydrocarbon group having a nitrogen atom or an organic residue having an aromatic ring and a heterocycle. or,
In the organic residue having an aromatic ring and a heterocycle, the aromatic ring may be bonded to the heterocycle, or the aromatic ring may be fused to the heterocycle, and n is 1.2 or 3 is shown.

Specific examples of the above-mentioned a-group are as follows.

(5) C2H5 Word (1°) -Q-〇- (14) -Q-CH=C-Q- (15) <H=H'<- (ts), H-cH=Nriichi (22) →M-CH=N-N=CH÷2H5 Specific examples of the azo compound represented by the general formula [2] are as follows.

M-(+) H3 M-(2) H3 M-(4) M-(6) H3 Diazo compound represented by general formula [2] D-(+) D-(2) D-(3) D- (5) D-(6) D-(7) D-(8) D-(9) D-(10) trt3 T-(2) CH3 Next, in a synthesis example for the azo compound used in the present invention. I will explain in detail.

Synthesis Example CD-(1) Disazo Compound] After cooling a dispersion consisting of 12.2 g of 3.3'-dimethoxybenzidine, 200 mL of water, and 30 mM of concentrated hydrochloric acid to 5°C, 7.2 g of sodium nitrite was added. A solution dissolved in 15 mJl of water was added dropwise to the above solution over a period of 30 minutes, and the temperature of the solution was kept at 4 to 7°C and stirred for 30 minutes.Activated carbon was then added and filtered to obtain a tetrazonium solution. Add 66 g of 42% 2% borofluoric acid to this tetrazonium solution, filter the precipitate with suction, and then
After washing twice with cold water, vacuum dry.15.
4 g of tetrazonium salt was obtained.

Next, a liquid consisting of 5.7 g of guaiazulene and 450 ml of dimethylformamide was cooled to 2°C. After adding 6.0 g of the tetrazonium salt obtained above to the liquid and dissolving it, 4.4 ml of pyridine was added dropwise into the liquid over 10 minutes while keeping the liquid at 4 to 8°C, and after stirring for 2 hours, It was left at room temperature overnight.

The crystals obtained by filtering the reaction solution were washed successively with DMF, benzene and ethanol, and then dried to obtain 3.8 g of purified pigment.

Yield based on tetrazonium salt: 43% Melting point: 22
Decomposition solution absorption spectrum from 3°C: Dichloromethane solution max=
537mm Elemental analysis: C44H46N402 Calculated value Analysis value C: 79.71 79.61H: 7
．． 01 7.18N: 8.45
8.40 The method for synthesizing the disazo pigment D-(1) has been described above, but other azo compounds represented by the general formula [2] can be synthesized in the same manner.

The photothermal conversion recording medium of the present invention can be used for optical disc recording. For example, a thin film 2 containing the above-mentioned organic compound can be formed on a substrate l as shown in FIG. . Such a thin film 2 has the above-mentioned general formula [2]
The compound represented by can be formed by vacuum evaporation, or by applying a coating liquid containing the above-mentioned organic compound in a binder. When forming a film by coating, the above-mentioned organic compound may be contained in the binder in a dispersed state or in an amorphous state, as a suitable binder.

A wide range of resins can be selected. Specifically, cellulose esters such as nitrocellulose, cellulose phosphate, cellulose sulfate, cellulose acetate, cellulose propionate, cellulose acetate, cellulose myristate, cellulose palmitate, acetic acid, cellulose propionate, cellulose acetate/butyrate, methyl cellulose, Cellulose ethers such as ethyl cellulose, propyl cellulose, butyl cellulose, polystyrene, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral,
Vinyl resins such as polyvinyl acetal, polyvinyl alcohol, polyvinylpyrrolidone, copolymer resins such as styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, polymethyl methacrylate, polymethyl acrylate , polybutyl acrylate, polyacrylic acid, polymethacrylic acid, polyacryamide, acrylic resins such as polyacrylonitrile, polyesters such as polyethylene terephthalate, poly(4,4'-isopropylidene diphenylene-co-1,4cyclohexyl) silane dimethylene carbonate), poly(ethylenedioxy-3,3'
-phenylene thiocarbonate), poly(4,4'-isopropylidene diphenylene carbonate coated terephthalate), poly(4,4'-isopropylidene diphenylene carbonate), BoIJ(4,4'-5ec- 7
'tylidene diphenylene carbonate), poly(4,4
polyarylate resins such as '-isopropylidene diphnylene carbonate block-oxyethylene), polyamides, polyimides, epoxy resins,
Phenol resins, polyolefins such as polyethylene, polypropylene, chlorinated polyethylene, etc. 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 dispersed or amorphous state, but in general, methanol is used. , alcohols such as ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, N, N-
Amides such as dimethylformamide, N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate, ethyl acetate, butyl acetate, chloroform, chloride Aliphatic halogenated hydrocarbons such as methylene, dichloroethylene, carbon tetrachloride, trichlorethylene, etc., or aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. can be used.

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

When forming the thin film 2 together with the binder, the content of the above-mentioned organic compound in the thin film 2 is 1 to 90% by weight,
Preferably it is 20 to 70% by weight. Further, the dry film thickness or vapor deposited film thickness of the thin film 2 is 10 microns or less, preferably 2 microns or less.

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

The photothermal conversion recording medium of the present invention has a substrate l used as a support.
The aforementioned thin on top! It is obtained by forming I2 (electromagnetic radiation sensitive layer), but various auxiliary layers can be provided.For example, a substrate having a surface coating made of an inorganic or organic substance on the surface of the substrate 1 for the purpose of adjusting the thermal constant. can be used. Further, a protective layer made of a transparent material can be provided on the electromagnetic radiation sensitive layer 2, and this protective layer is effective in preventing mechanical damage and can be formed with an appropriate thickness. Since it can be used as an antireflection film, it is also effective in improving sensitivity. Further, as shown in FIG. 2, a reflective layer 3 can be provided between the electromagnetic radiation sensitive layer 2 and the substrate l. 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 optical recording medium of the present invention is disclosed in Japanese Patent Application No. 57-72374.
It is possible to form a pregroove having functions such as a track guide groove and an address designation groove as described in the specification of the above patent.

The photothermal conversion recording medium of the present invention has a thin film 2 as shown in FIG.
Electromagnetic radiation 4, such as gallium-arsenic-aluminum semiconductor laser (oscillation wavelength: 820 nm), argon gas laser (oscillation wavelength: 488,515 nm), helium-neon gas laser (oscillation wavelength: 632.8 nm), and other sources from the visible range to the infrared range 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 an oscillation wavelength of 300 nm, infrared lamp light, or a heater. The reflectance of the pit-formed area is different from that of the non-pit-formed area, so pits are formed by, for example, scanning electromagnetic radiation along the track, and the pit-formed area and the non-pit-formed area are A low-power laser is scanned along the track, and the difference in reflectance can be read by a photodetector.

The effects of the present invention are listed below.

In the photothermal conversion recording medium of the present invention, the electromagnetic radiation sensitive layer has high absorption efficiency for electromagnetic radiation.

Recording is possible with a low energy density helium-neon gas laser or xenon flash lamp, and is also effective for recording with a semiconductor laser with an oscillation wavelength on the long wavelength side. 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.

In another specific example of the present invention, the liquid crystal composition 108 can be applied as a photothermal conversion recording type liquid crystal element.For example, as shown in FIG. A liquid crystal in which a compound represented by general formula [2] is dissolved is used. Smectic liquid crystal is suitable for the liquid crystal used in the device of the present invention, and in particular, A phase or C phase of smectic liquid crystal having positive dielectric anisotropy. 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 rises, the phase changes from the smectic phase of the homeotropic structure to the nematic-intropic phase. Next, when the isotropic phase changes 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 a liquid crystal element is locally heated to an intropic phase by irradiation with a laser beam, and then rapidly cooled, the area becomes a smectic phase with a false calconic structure, and this state has light scattering properties. A still image pattern can be formed by scanning an optical signal using the laser beam described above.

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-6-150030, JP-A-57-40429, JP-A-57-51779, etc. can be used.

The compound represented by the above general formula [2] is.

0.1% by weight or more, preferably 1% by weight or more based on the liquid crystal
It can be contained in the liquid crystal composition 108 in a range of 3% by weight.

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% 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 chlorodecanoate, cholesteryl butyrate, cholesteryl caprate, cholesteryl oleate, cholesteryl oleate, cholesteryl laurate, Examples include cholesteryl compounds such as cholesteryl myristate, cholesteryl hebutycarbamate, cholesteryl decyl ether, cholesteryl lauryl ether, and cholesteryl oleyl ether.

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.

A liquid crystal element recorded by the above-mentioned method uses a liquid crystal composition l.
After heating O8 over the entire surface, for example, with a heater, to cause a phase change to the introbic phase.

A lot of substrates constituting a liquid crystal element and 102 (for example,
By applying an appropriate direct current or alternating current between electrodes 103 and 104 provided on a plastic plate (such as a transparent glass plate or an acrylic plate) and slow cooling, the phase changes from an introbic phase to a nematic phase to a smectic phase. can occur. At this time, since the liquid crystal is in the nematic phase and has positive dielectric anisotropy, the nematic liquid crystal is aligned in the direction of the electric field, and a smectic A phase or C phase with a homeotropic structure is further formed to cool the written image. The pattern will be erased. Electrodes 103 and 104 are generally made of isodium oxide, tin oxide or ITO (Indium Oxide).
It can be obtained with a transparent conductive film such as Tin Oxide, or, if necessary, with a metal conductive film such as aluminum, chromium, silver or nickel. This electrode 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. It is also possible to design

The liquid crystal element of the present invention has alignment control fi 106 and fi 1 which are made of a film of an insulating material on the respective electrodes 103 and 104.
07 can be provided.

The alignment control films 106 and 107 have a surface structure that allows the alignment direction of the liquid crystal composition 108 in contact with these critical surfaces to be controlled to a desired state. In addition, the alignment side mm1oe and 107 also function as an insulating film that can prevent the generation of current flowing through the liquid crystal composition 108. This type of orientation side WMs 106 and 107 are, 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,
Vapor deposition of insulating materials such as polyesterimide, polyparaxylerin, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin, organosiloxane, polyethylene fluoride, etc. It can be obtained by forming a film using a dip coating method, a spinner coating method, or a spray coating method.

The alignment control films 106 and 107 have surfaces on which the liquid crystal composition 108 is homogeneously aligned by rubbing the surfaces with cloth, paper, velvet, etc., or by using an oblique vapor deposition method during film formation, depending on a predetermined writing method. Silane compounds having a perfluoroalkyl group on the surface, such as those described in JP-A-50-36150, JP-A-50-50947;
By treating with compounds such as alkyltrialkoxysilanes described in JP-A-50-63955 and tetraalkoxysilanes described in JP-A-50-63955,
The liquid crystal composition 108 can have a surface structure that homeotropically aligns it.

The optimum thickness of the alignment control films 106 and 107 varies depending on the type of insulating material used, but generally it is 10.
It is suitable to set it in the range of 0 to 1000 people, preferably in the range of 500 to 2000 people, and furthermore, the film thickness is set so that the alignment control films 108 and 107 also act as antireflection films. This is desirable.

In addition, 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 109 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 600 mm or more. in particular,
Ge/MgF2 (1/4 person) / G e O2 (
1/4 people)/MgF2 (174 people)/GeO2 (1/
A multilayer film consisting of 4 people) is known. However, in the present invention, the use of cold mirror 105 can also be omitted. Further, in the device of the present invention, a cold filter (not shown) can be provided between the electrode 103 and the alignment control film IO6. This cold filter has a sufficiently high transmittance for visible light and a sufficiently high reflectance for long wavelengths.

EXAMPLES Hereinafter, the present invention will be explained in detail according to examples, but the present invention is not limited thereto.

Example 1 1 part by weight of acetonitrile styrene copolymer resin (manufactured by Mitsui Toatsu Chemical Co., Ltd., Lightac A330PC), the above-mentioned compound D
- (1) 5 parts by weight and 60 parts by weight of dichloromethane were thoroughly mixed in a ball mill. This mixed liquid is
After coating on a disc-shaped aluminum vapor-deposited glass plate of cm by spinner coating method, it is dried to give a coating of 0.4 g/c.
A recording layer of rn' was obtained.

The optical disk recording body thus created was mounted on a turntable, and the turntable was rotated to 1100 orps using a motor.
Recording was performed by scanning the surface of the recording layer in a track shape with a helium-neon laser (oscillation wavelength: 632.8 nm) concentrated at a spot size of 1.0 microns, with an output of 10 mW and a pulse width of 2 MHz.

When the surface of this recorded optical disc was observed using a scanning electron microscope, clear pits were observed. Furthermore, when a 1 mW helium-neon laser was applied to this disk and the 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 95% 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 1 mW helium-neon laser was applied to the recorded and durability-tested recording medium and the reflected light was detected, a waveform with a sufficiently high S/N ratio was obtained.

Example 2 The above-mentioned compound M-(2) was coated on a disc-shaped aluminum vapor-deposited glass plate with a diameter of 20 cm using a spinner coating method in the same manner as in Example 1 to give a coating composition of 0.4 g/m.
An optical disc recording medium having a recording layer of 1 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 3 The above-mentioned compound M-(6) was coated on a disc-shaped aluminum vapor-deposited glass plate with a diameter of 20 cm using a spinner coating method in the same manner as in Example 1 to give 0.4 g/
An optical disc recording medium having a recording layer of m' 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 4 The above-mentioned compound D-(3) was coated on a disc-shaped aluminum vapor-deposited glass plate with a diameter of 20 cm using a spinner coating method in the same manner as in Example 1 to give a coating composition of 0.5 g/m.
An optical disc recording medium having a recording layer of 1 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-mentioned compound D-(5) 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, and 0.5 g of the compound was coated using a spinner coating method.
An optical disc recording medium having a recording layer of /m' 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, a clear focus was 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 D-(8) was coated on a disc-shaped aluminum vapor-deposited glass plate with a diameter of 20 cm using a spinner coating method in the same manner as in Example 1 to give a coating composition of 0.5 g/m.
An optical disc recording medium having a recording layer of `` 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. or.

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 7 The above-mentioned compound D-(10) was coated on a disc-shaped aluminum vapor-deposited glass plate with a diameter of 20 cm using a spinner coating method in the same manner as in Example 1 to give 0.5 g/
rrl's notes! An optical disc recording medium having layers 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 the same results were obtained.

Example 8 12 parts by weight of a nitrocellulose solution (manufactured by Daicel Chemical Industries, Ltd.; Ohares Lacquer 25% by weight solution of dinitrocellulose in methyl ethyl ketone), the above-mentioned compound T-(1
), 3 parts by weight of methyl ethyl ketone and 60 parts by weight of methyl ethyl ketone were thoroughly mixed in a ball mill. Pour this mixture into a diameter of 20 cm.
It was coated on a disc-shaped aluminized glass plate using a spinner coating method, and then dried to give a coating weight of 0.2 g/
A recording layer of cr rn' was obtained.

The optical disk recording medium created in this way is mounted on a turntable, and the turntable is turned to LOOORPM by a motor.
While giving a rotation of
Recording was performed by scanning a recording layer (0 nm) in a track shape on the surface of the recording layer.

When the surface of this recorded optical disc was observed using a scanning electron microscope, clear pits were observed. In addition, when a 1 mW gallium-aluminum-arsenic semiconductor laser was incident on this disk and the 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 95% 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 1 mW gallium-arsenide-aluminum semiconductor laser was incident on the recorded and durability-tested recording medium and the reflected light was detected, a waveform with a sufficiently high S/N ratio was obtained.

Example 9 The above-mentioned compound T-(2) was coated on a disk-shaped aluminum vapor-deposited glass plate with a diameter of 20 cm by spinner coating method in the same manner as in Example 1, and the compound was coated with o, 2 g/
An optical disc recording medium having a recording layer of rn' 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 10 The above-mentioned compound T-(3) was coated on a disc-shaped aluminum vapor-deposited glass plate with a diameter of 20 cm using a spinner coating method in the same manner as in Example 1 to give 0.2 g/
An optical disc recording medium having a recording layer of m' 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. or.

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 11 An example in which a display pattern was formed using the liquid crystal element of the present invention is shown in FIG.
, 4'-cyanooctylbiphenyl (having positive dielectric anisotropy) 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, the liquid is injected into a cell whose inner wall surface has been subjected to homeotropic alignment treatment, and then slowly cooled. A smectic phase liquid crystal with a homeotropic 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. neon laser.

A long wavelength laser beam emitted from 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 the modulator 20
3. Slit 204, Y-axis deflector 205, X-axis deflector 2
06, the light is modulated and deflected, is focused by a writing lens 208, and is irradiated from the back side of the liquid crystal element 201 via a gicroic mirror 209. The aforementioned modulator 203, Y-axis deflector 205, and X-axis deflector 206 are
A driving amplifier 210 is connected to a signal source 211 to control a laser beam and convert a 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 212 attached to the periphery of the liquid crystal element 201 is activated by the power supply 213 to rapidly cool the liquid crystal element 201, forming a smectic phase with a focal conic structure, and irradiating the optical signal. An image pattern was formed in which the exposed areas were in a light scattering state. At this time, the temperature of the Venirtier 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 above-mentioned image pattern, the transparent heater 21B (for example, indium oxide film, tin oxide film, ITO film) provided on the liquid crystal element 201 is connected to the temperature controller 2.
The liquid crystal layer is heated by a heater power source 218 via a heater power source 218 to cause a phase change from a liquid crystal phase to an intropic phase. After that, while applying a voltage from the AC power supply 221 between the electrodes 219 and 220 provided on the liquid crystal element 201, the liquid crystal element 20
1 was slowly cooled to form a smectic phase with a homeotropic structure.

As a result, the written image pattern was erased.

The liquid crystal element of the present invention can be applied to a large screen display, and can also be applied to an optical disk system using a recording method in which pits are formed by scanning an optical signal containing predetermined information along a track. be able to.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of the photothermal conversion recording medium for optical disks of the present invention. FIG. 3 is an explanatory diagram showing an embodiment of the photothermal conversion recording medium. FIG. 4 is a sectional view of the liquid crystal element of the present invention. FIG. 5 is an explanatory diagram showing one example of a display method using the liquid crystal element of the present invention. l: Substrate 2: Thin film 3: Reflective layer 4: Electromagnetic radiation 5: Bit 101.102: Substrate 103.104: Electrode 105: Cold mirror 106.107: Alignment control film 108: Liquid crystal composition 109: Observation light 110 :Laser beam

Claims (3)

[Claims] (1) A photothermal conversion recording medium characterized by containing an azo compound having at least one kind of azo group bonded to a coupler residue represented by the following general formula [1]. General formula [1] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ However, in general formula [1], R1, R2, R3, R4, R5, R6, and R7 are hydrogen atoms, halogen atoms, or monovalent organic residues. Representation, also R1 and R2,
At least one combination of R2 and R3, R3 and R4, R4 and R5, R5 and R6, and R6 and R7 may form a substituted or unsubstituted fused ring. (2) The photothermal conversion recording medium according to claim 1, comprising a substrate and a coating having an azo compound containing at least one azo group bonded to a coupler residue represented by the following general formula [1]. General formula [1] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ However, in general formula [1], R1, R2, R3, R4, R5, R6, and R7 are hydrogen atoms, halogen atoms, or monovalent organic residues. Representation, also R1 and R2,
At least one combination of R2 and R3, R3 and R4, R4 and R5, R5 and R6, and R6 and R7 may form a substituted or unsubstituted fused ring. (3) The photothermal conversion record according to claim 1, comprising a liquid crystal composition containing a liquid crystal and an azo compound containing at least one azo group bonded to a coupler residue represented by the following general formula [1]. Medium. General formula [1] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ However, in general formula [1], R1, R2, R3, R4, R5, R6, and R7 are hydrogen atoms, halogen atoms, or monovalent organic residues. Representation, also R1 and R2,
At least one combination of R2 and R3, R3 and R4, R4 and R5, R5 and R6, and R6 and R7 may form a substituted or unsubstituted fused ring.