JP2006301268A - Image display device and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display element which has high durability, under repeated use. <P>SOLUTION: The present invention is an image display device comprising an electrode layer, a layer including at least one layer of the electrochromic dye, and a layer including a fluorescent whitening agent which can absorb 90% or higher of at least one layer of a light of 200-410 nm, and an image forming method which uses the image display device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image display device including an electrochromic dye and an image forming method, and more particularly to an image display device including a layer containing a specific fluorescent whitening agent and including an electrochromic dye, and an image using the image display device. It relates to a forming method.

  In recent years, there has been a demand for providing full-color display materials that are bright and easy to see and have low power consumption. For example, self-luminous elements such as CRT, PDP, and ELD are bright and easy to see, but have a problem of high power consumption. Also, various display methods have been proposed as an image display device called so-called electronic paper.

  As for a liquid crystal display element (LCD), a transmissive LCD uses a backlight, and thus consumes a little power, has a viewing angle dependency, and cannot be said to be bright and easy to see. In addition, the reflective LCD consumes less power but has a viewing angle dependency and forms a color image by the side-by-side mixing method using a color filter, but this method cannot express white and produces a dark screen. There is a problem of becoming. Further, in the reflection type display element in which two to three layers of elements are laminated, the structure becomes complicated, and technical problems for establishing a manufacturing process are difficult, and there is a problem that the manufacturing cost becomes high. .

  On the other hand, a display element using a dye whose light absorption of a substance reversibly changes by an electrochemical oxidation-reduction reaction, a so-called electrochromic dye (hereinafter sometimes referred to as an “EC dye”) is applied to an electrochromic element ( EC element). The EC element has, for example, a structure in which a thin film containing an EC dye and an electrolytic solution or a solid electrolyte are stacked between transparent electrodes, or a structure in which an EC dye is dissolved in an electrolytic solution. An EC element reversibly generates an entire surface of a thin film containing an EC dye by an electrochemical oxidation-reduction reaction by applying a voltage to the laminated thin film containing the EC dye and the solid electrolyte through a transparent electrode. Decolorization reaction.

Since the EC element has a low driving voltage, a memory property, and a light absorption type, a clear display with no viewing angle dependency can be obtained even under strong external light. For this reason, it has the characteristic outstanding as a glare-proof mirror for motor vehicles, and light control glass.
Further, the EC element does not require a polarizing plate or the like, has no viewing angle dependency, has a light receiving type and has excellent visibility, has a simple structure, and can be easily enlarged.
Furthermore, by selecting a thin film containing the EC dye, various color tones can be obtained, and the display state can be stopped (ie, having a memory property) simply by blocking the movement of electrons and maintaining the redox state.
EC elements do not require power to maintain the display state, and have various advantages such as low power consumption (see, for example, Patent Documents 1 to 3).

On the other hand, although the optical writing method can be applied on a plastic substrate, the conventional EC element has a problem that the EC dye is decomposed by irradiation with ultraviolet rays when repeatedly used.
In order to suppress the decomposition of the EC dye due to the irradiation of ultraviolet rays, an EC element having an ultraviolet absorbing layer containing a compound that absorbs ultraviolet rays has been proposed (for example, see Patent Document 4), but still insufficient. There was a case. In this proposal, a benzotriazole-based compound is used, and 410 nm light is transmitted through 10% or more due to its spectral characteristics.
Japanese Patent Laid-Open No. 9-120088 JP 7-152050 A JP-A-6-242474 JP-A-8-271872

Under such circumstances, the inventors have examined that, in order to realize an electronic paper with high display performance, it is necessary to produce an EC element, but there is a problem that the performance of the EC dye deteriorates due to ultraviolet irradiation. I found out.
An object of the present invention is to solve the above-described problem, and an EC display device that is not easily deteriorated due to decomposition or the like due to ultraviolet irradiation, and has a high display performance, and an image forming method using the image display device The purpose is to provide.

  Under such circumstances, as a result of intensive studies by the inventors, it has been found that the problems of the present invention can be solved by adopting the following means.

<1> On the support, an electrode layer, a layer containing at least one electrochromic dye, and at least one layer containing a fluorescent brightener that absorbs 90% or more of light of 200 nm to 410 nm inclusive. An image display device comprising:

<2> The image display device according to <1>, wherein the layer containing the fluorescent brightening agent further contains an ultraviolet absorber.

<3> A first electrode layer, a layer containing at least one electrochromic dye, a photoconductive layer, a layer containing the fluorescent brightening agent, and a second electrode layer on the support, the first electrode The image display device according to <1> or <2>, wherein the electrochromic dye-containing layer and the photoconductive layer are provided between electrode layers including the layer and the second electrode layer.

<4> At least one of the first electrode layer and the second electrode layer is a transparent electrode, and a semiconductor nanoporous layer is provided between the electrode layers adjacent to one or both of the transparent electrodes. The image display device according to <3>, wherein the porous layer is a layer containing the at least one electrochromic dye.

<5> The method according to any one of <1> to <4>, wherein the layer containing at least one electrochromic dye is a layer containing a plurality of electrochromic dyes that develop different colors. The image display device described.

<6> The image display device according to any one of <3> to <5>, wherein the photoconductive layer contains an organic photoconductor as a main component.

<7> The image display element according to any one of <1> to <6>, wherein the electromic dye is an organic dye.

<8> The image display device according to any one of <3> to <7>, wherein conductivity of the photoconductive layer is changed by visible light.

<9> The image display device according to any one of <1> to <8>, wherein the optical brightener is a benzoxazole derivative.

<10> The image display device according to <9>, wherein the benzoxazole derivative is represented by the following general formula (1).

In general formula (1), R ¹ and R ⁴ each independently represent a hydrogen atom, an alkyl group or an alkoxy group, R ² and R ³ represent an alkyl group, and A represents a substituted aryl or ethenyl group. To express.

<11> Using the image display device according to any one of <1> to <10>, light of 200 nm to 410 nm is absorbed by 90% or more, and substantially light of 410 nm to 700 nm is absorbed. An image forming method characterized by performing optical writing.

  According to the present invention, by having at least one layer containing a fluorescent brightening agent that absorbs 90% or more of light of 200 nm to 410 nm, the EC dye is hardly deteriorated due to decomposition or the like due to ultraviolet irradiation. A high image display device, preferably an optically written image display device, and an image forming method using these image display devices can be provided. Furthermore, when a photoconductive layer (particularly, an organic photoconductor (layer)) is provided, photodecomposition of the photoconductive layer is suppressed and durability is improved.

  Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

The image display device of the present invention has, on a support, an electrode layer, a layer containing an electrochromic dye, and a layer containing a fluorescent brightening agent that absorbs 90% or more of light of 200 nm to 410 nm. Features.
In some cases, the EC dye is decomposed by ultraviolet rays. In the present invention, by separately providing a layer containing a fluorescent brightening agent that absorbs 90% or more of light of 200 nm or more and 410 nm or less, the performance of the EC dye can be improved. It was not deteriorated by irradiation and succeeded in improving durability.
In addition, compared with the case of the invention such as JP-A-8-271872 in which an ultraviolet absorbing layer containing an ultraviolet absorber is provided, when a layer containing a fluorescent brightening agent is separately provided, at the same time, deterioration due to ultraviolet irradiation is suppressed, Since the whiteness in white background display is increased, it is possible to display an image with excellent visibility.

<Support>
As the support used in the present invention, a plastic substrate, a glass substrate, paper, a metal substrate or the like is used, and a plastic substrate is preferable. Examples of the plastic substrate include triacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), polyarylate ( PAr), polysulfone (PSF), polyester sulfone (PES), polyetherimide (PEI), cyclic polyolefin, polyimide (PI) and the like. Polyethylene terephthalate (PET) is preferable.

  The resin preferably has a thermal expansion coefficient of 30 ppm / ° C. or less. The thermal expansion coefficient said here was measured in TMA8310 (The Rigaku Denki Co., Ltd. make, Thermo Plus series). For example, PET (East Reel Miller, 15 ppm / ° C.), PEN (DuPont-Teijin Q65A 20 ppm / ° C.), PI (Ube Industries Upilex, 20 ppm / ° C.), aramid resin (Teijin, 2 ppm / ° C.) and the like can be mentioned.

  Further, by adding an inorganic substance such as a sol-gel method, glass cloth, or glass fiber to a resin having a glass transition point (Tg) of 150 ° C. or higher as described below, a thermal expansion coefficient of 30 ppm or less may be achieved. .

  Preferable examples (temperature in parentheses indicates Tg), polycarbonate resin (for example, Idemitsu Kosan Co., Ltd., Toughlon, PC: 140 ° C.), alicyclic polyolefin resin (for example, manufactured by Nippon Zeon Co., Ltd .; ZEONOR 1600) : 160 ° C, manufactured by JSR Corporation; Arton: 170 ° C, polyarylate resin (manufactured by Unitika; U polymer, PAr: 210 ° C), polyethersulfone resin (manufactured by Sumitomo Chemical; polyethersulfone, PES: 220) ° C), polysulfone resin (Toray Industries, Inc .; Tresulfone, PSF: 190 ° C), polyester resin (eg Kanebo Co., Ltd .; O-PET: 125 ° C, polyethylene terephthalate, polyethylene naphthalate), cycloolefin copolymer (COC: special Compound of Example 1 of open 2001-150584: 162 ° C., fluo Ring-modified polycarbonate resin (BCF-PC: compound of Example 4 of JP-A 2000-227603: 225 ° C.), alicyclic modified polycarbonate resin (IP-PC: compound of Example 5 of JP-A 2000-227603): 205 ° C.) and acryloyl compounds (the compound of Example-1 of JP-A-2002-80616: 300 ° C. or higher). A polycarbonate resin having a bisphenol component represented by the following formula (A) as a bisphenol component is also preferred.

In the general formula (A), R ²¹ , R ²² , R ²³ and R ²⁴ are each independently a hydrogen atom, an alkyl group or an aryl group, and X is a cycloalkylene group having 5 to 10 carbon atoms and a carbon number It is a 7-15 araalkylene group or a C1-C5 haloalkylene group.

  Examples of the cycloalkylene group having 5 to 10 carbon atoms represented by X include 1,1-cyclopentylene group, 1,1-cyclohexylene group, 1,1- (3,3,5-trimethyl) cyclohexylene. Group, norbornane-2,2-diyl group, tricyclo [5.2.1.2.6] decane-8,8'-diyl group, especially 1,1-cyclohexylene group, 1,1 -(3,3,5-trimethyl) cyclohexylene group is preferably used.

  Examples of the aralkylene group having 7 to 15 carbon atoms represented by X include a phenylmethylene group, a diphenylmethylene group, a 1,1- (1-phenyl) ethylene group, and a 9,9-fluorenylene group.

  Examples of the haloalkylene group having 1 to 5 carbon atoms represented by X include a 2,2-hexafluoropropylene group and a 2,2- (1,1,3,3-tetrafluoro-1,3-dicyclo) propylene group. Etc. are preferably used.

  The resin used as the plastic substrate of the present invention may have only one type of structural unit, or two or more types may be mixed. Further, structural units other than those described above may be included within the range not impairing the effects of the present invention. Such other structural units are preferably 50 mol% or less, more preferably 10 mol% or less of the whole. In addition, the resin used as the plastic substrate of the present invention may be blended with a resin other than those described above without departing from the gist of the present invention, and may be composed of two or more kinds of resins. .

  The molecular weight of the resin used as the plastic substrate of the present invention is preferably a number average molecular weight of 10,000 to 300,000 (polystyrene conversion), more preferably 20,000 to 200,000, still more preferably. 30,000 to 150,000. By setting the molecular weight in such a range, the mechanical strength of the plastic substrate can be made more preferable.

As the plastic substrate used for the support in the present invention, a crosslinked resin can also be preferably used from the viewpoint of solvent resistance, heat resistance and the like. As the kind of the cross-linked resin, various known ones can be used without particular limitation for both the thermosetting resin and the radiation curable resin.
Examples of the thermosetting resin include phenol resin, urea resin, melamine resin, unsaturated polyester resin, epoxy resin, silicone resin, diallyl phthalate resin, furan resin, bismaleimide resin, cyanate resin and the like.
The crosslinking method can be used without particular limitation as long as it is a reaction that forms a covalent bond, and the system in which the reaction proceeds at room temperature using a polyalcohol compound and a polyisocyanate compound to form a urethane bond is not particularly limited. Can be used. However, such a system often has a problem of pot life before film formation, and is usually used as a two-component mixed type in which a polyisocyanate compound is added immediately before film formation. On the other hand, when used as a one-component type, it is effective to protect the functional group involved in the crosslinking reaction, and it is also commercially available as a block type curing agent. As commercially available block type curing agents, B-882N manufactured by Mitsui Takeda Chemical Co., Ltd., Coronate 2513 manufactured by Nippon Polyurethane Industry Co., Ltd. (above block polyisocyanate), Cymel 303 manufactured by Mitsui Cytec Co., Ltd. (methylated melamine resin) ) Etc. are known. A blocked carboxylic acid represented by the following B-1 that protects a polycarboxylic acid that can be used as a curing agent for an epoxy resin is also known.

Radiation curable resins are roughly classified into radical curable resins and cationic curable resins. As the curable component of the radical curable resin, a compound having a plurality of radical polymerizable groups in the molecule is used. As a typical example, a polyfunctional acrylate monomer having 2 to 6 acrylate groups in the molecule And compounds having a plurality of acrylate groups in the molecule called urethane acrylate, polyester acrylate, and epoxy acrylate.
As a typical curing method of the radical curable resin, there are a method of irradiating an electron beam and a method of irradiating ultraviolet rays. Usually, in the method of irradiating with ultraviolet rays, a polymerization initiator that generates radicals upon irradiation with ultraviolet rays is added. In addition, if the polymerization initiator which generate | occur | produces a radical by heating is added, it can also be used as a thermosetting resin.
As the curable component of the cationic curable resin, a compound having a plurality of cationic polymerizable groups in the molecule is used, and as a typical curing method, a photoacid generator that generates an acid by irradiation with ultraviolet rays is added, A method of curing by irradiating with ultraviolet rays is mentioned. Examples of the cationically polymerizable compound include a compound containing a ring-opening polymerizable group such as an epoxy group and a compound containing a vinyl ether group.

  In the plastic substrate, a plurality of the thermosetting resins and radiation curable resins mentioned above may be mixed and used, or a thermosetting resin and a radiation curable resin may be used in combination. Moreover, you may mix and use a crosslinkable resin and the polymer which does not have a crosslinkable group.

  Furthermore, when these crosslinkable resins are used in a mixture with a resin used as a plastic substrate, the solvent resistance, heat resistance, optical properties, and toughness of the obtained plastic substrate can be satisfied. Moreover, it is also possible to introduce a crosslinkable group into these resins, and it may have a crosslinkable group at any position in the polymer main chain terminal, the polymer side chain, or the polymer main chain. In this case, a plastic substrate may be produced without using the general-purpose crosslinkable resin mentioned above.

  These resins may be stretched. By stretching, mechanical strength such as folding strength is improved, and there is an advantage that handling property is improved. In particular, those having an orientation release stress in the stretching direction (ASTM D1504, hereinafter abbreviated as ORS) of 0.3 to 3 GPa are preferred because the mechanical strength is improved. ORS is the internal stress caused by stretching that is frozen in a stretched film or sheet. For stretching, a known method can be used. For example, a roll uniaxial stretching method, a tenter uniaxial stretching method, a simultaneous biaxial stretching at a temperature between 10 ° C. and 50 ° C. higher than the glass transition temperature (Tg) of the resin. The film can be stretched by a method, a sequential biaxial stretching method, or an inflation method. The draw ratio is preferably 1.1 to 3.5 times.

The thickness of the plastic substrate used for the support in the present invention is not particularly limited, but is preferably 30 μm to 700 μm, more preferably 40 μm to 200 μm, and still more preferably 50 μm to 150 μm.
Further, in any case, the haze is preferably 3% or less, more preferably 2% or less, further preferably 1% or less, and the total light transmittance is preferably 70% or more, more preferably 80% or more, and further preferably 90%. That's it. The haze is measured by a haze meter (for example, manufactured by Nippon Denshoku Industries Co., Ltd.), and the total light transmittance is measured by visible / ultraviolet absorption spectroscopy.

  For plastic substrates, resins such as plasticizers, dyes and pigments, antistatic agents, ultraviolet absorbers, antioxidants, inorganic fine particles, release accelerators, leveling agents, and lubricants are used as long as they do not impair the effects of the present invention. A modifier may be added.

  The plastic substrate may be either light transmissive or non-light transmissive. When a non-light transmissive support is used as the support, a white support having light reflectivity can be used. Examples of the white support include a plastic substrate to which an inorganic pigment such as titanium oxide or zinc oxide is added. In addition, when the said support body comprises a display surface, it needs to have a light transmittance at least with respect to the light of visible region.

<Electrode layer>
As the electrode layer used in the present invention, a metal oxide typified by tin oxide-indium oxide (ITO), tin oxide, zinc oxide or the like is preferably used. As for the light transmittance, a transparent electrode having a light transmittance of at least 50% or more is preferably used. As for the transparent electrode, for example, those described in pages 232 to 239 of “Liquid Crystal Device Handbook” (edited by the Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989) are used. The transparent electrode can be formed by a sputtering method, a sol-gel method, or a printing method.

  In the case of a reflective optical element, as the electrode far from the viewing direction, in addition to a metal oxide layer represented by tin oxide-indium oxide (ITO), tin oxide, zinc oxide, etc., conductive Or a metal layer represented by carbon, copper, aluminum, gold, silver, nickel, platinum, or the like can be used.

<Layer containing electrochromic dye>
The layer containing an electrochromic dye (EC dye) in the present invention (hereinafter sometimes referred to as “EC layer”) is not particularly defined as long as it is a layer containing an electrochromic dye. For example, the EC dye is an electrolyte layer. (Hereinafter, sometimes referred to as “electrolyte EC layer”), a layer in which an EC dye is contained in a semiconductor nanoporous layer described later, and the like. Of course, the EC layer may be configured separately from the electrolyte layer and the semiconductor layer.

  The EC dye is reversibly blackened or decolored by an oxidation-reduction reaction. Specifically, the light transmittance at a wavelength of 300 to 750 nm is preferably 10% or less, and a wavelength of 350 to 700 nm. The light transmittance is more preferably 10% or less, and the light transmittance at a wavelength of 400 to 600 nm is further preferably 10% or less. The EC dye exhibiting such color development and decoloring behavior is not particularly limited, but two or more EC dyes are preferably used in combination, and specific combinations will be described later.

(Semiconductor nanoporous layer)
The semiconductor nanoporous layer is formed between at least one or both of the inner surfaces of the electrodes between the first electrode layer and the second electrode layer, and preferably on the surfaces of both electrodes. It is a case where it is formed. Here, it is extremely preferable that the electrode layer on the side where the semiconductor nanoporous layer is formed is transparent.
The semiconductor nanoporous layer has a porous structure so that the surface and the inside thereof have many micropores capable of supporting an EC dye and, if necessary, a charge transfer agent.

  The semiconductor nanoporous layer is formed in a multilayer structure, for example, 2 to 4 layer structure, and the same kind of EC dye is supported on each semiconductor nanoporous layer of the multilayer structure. Strength can be increased. Moreover, blackening can be easily achieved by carrying EC dye of a different color for each layer of the semiconductor nanoporous layer having a multilayer structure.

The specific surface area of the semiconductor nano-porous layer is preferably from ^{1~5000m 2 / g, 10~2500m 2 /} g is more preferable. Here, the specific surface area means the BET specific surface area obtained from the adsorption amount of nitrogen gas. If the specific surface area is too small, the adsorption amount of the EC dye cannot be increased, and the object of the present invention may not be achieved.

  The semiconductor fine particles contained in the semiconductor nanoporous layer are not particularly limited and may be appropriately selected according to the purpose. For example, a single semiconductor, an oxide semiconductor, a compound semiconductor, an organic semiconductor, a composite oxide semiconductor Or a mixture thereof, which may contain impurities as a dopant. There is no particular limitation on the form of the semiconductor, and it may be single crystal, polycrystal, amorphous, or a mixed form thereof.

  Examples of the single semiconductor include silicon (Si), germanium (Ge), and tellurium (Te).

The oxide semiconductor is a metal oxide and has semiconductor properties. For example, TiO ₂ , SnO ₂ , Fe ₂ O ₃ , SrTiO ₃ , WO ₃ , ZnO, ZrO ₂ , Ta ₂ O ₅ , Nb ₂ Examples thereof include O ₅ , V ₂ O ₅ , In ₂ O ₃ , CdO, MnO, CoO, TiSrO ₃ , KTiO ₃ , Cu ₂ O, sodium titanate, barium titanate, and potassium niobate.

  Examples of the compound semiconductor include cadmium sulfide, zinc sulfide, lead sulfide, silver sulfide, antimony sulfide, bismuth sulfide, cadmium selenide, lead selenide, cadmium Examples include telluride, zinc phosphide, gallium phosphide, indium phosphide, cadmium phosphide, gallium-arsenic selenide, copper-indium selenide, copper-indium sulfide, and the like.

  Examples of the organic semiconductor include polythiophene, polypyrrole, polyacetylene, polyphenylene vinylene, polyphenylene sulfide, and the like.

Examples of the complex oxide semiconductor include SnO ₂ —ZnO, Nb ₂ O ₅ —SrTiO ₃ , Nb ₂ O ₅ —Ta ₂ O ₅ , Nb ₂ O ₅ —ZrO ₂ , Nb ₂ O ₅ —TiO ₂ , _{Ti-SnO 2, Zr-SnO} 2, Bi-SnO 2, In-SnO 2, and the like. The SnO ₂ —ZnO is obtained by coating relatively large ZnO particles (particle size: about 0.2 μm) around the center with SnO ₂ ultrafine particles (particle size: about 15 nm). _{SnO 2: ZnO = 70: 30~30} : is preferably in the range of 70. The _{Nb 2 O 5 -SrTiO 3, Nb} 2 O 5 -Ta 2 O 5, Nb 2 O 5 -ZrO 2, and Nb ₂ O ₅ complex, such as Nb ₂ O ₅ -TiO ₂ includes a Nb ₂ O ₅ The mass ratio is 8: 2 to 2: 8.

  The shape of the semiconductor fine particles is not particularly limited and may be appropriately selected depending on the purpose. The shape may be any of a spherical shape, a nanotube shape, a rod shape, and a whisker shape. Fine particles can also be mixed. In the case of the spherical particles, the average particle size is preferably 0.1 to 1000 nm, and more preferably 1 to 100 nm. Two or more kinds of fine particles having different particle size distributions may be mixed. In the case of the rod-like particles, the aspect ratio is preferably 2 to 50000, and more preferably 5 to 25000.

  The method for forming the semiconductor nanoporous layer is not particularly limited and may be appropriately selected depending on the type of semiconductor. For example, metal anodization, cathode deposition, screen printing, sol-gel method, heat Examples include oxidation, vacuum deposition, DC and RF sputtering, chemical vapor deposition, metal organic chemical vapor deposition, molecular beam deposition, laser ablation, and the like. A porous layer can also be produced.

(Method for forming oxide semiconductor nanoporous layer)
As one method for forming an oxide semiconductor (metal oxide) nanoporous layer, in a solution containing a metal oxide precursor and a compound having one or more functional groups that interact with the metal oxide precursor A first step of producing a composite gel by reacting the metal oxide precursor to obtain a colloidal dispersion sol composed of metal oxide fine particles, and applying the sol to a support and drying or baking the sol And a second step of forming a semiconductor nanoporous layer having micropores on the transparent conductive film on the transparent insulating substrate (hereinafter also referred to as “composite gelation method”). ).

  In the first step, since the formation reaction of metal oxide fine particles proceeds in a gel whose diffusion is restricted, colloid in which fine particles having a small particle diameter are uniformly dispersed without formation of coarse particles or sedimentation of particles. A dispersed sol solution can be obtained. In the so-called sol-gel method, when metal oxide precursors are, for example, metal alkoxides, they are gelled by hydrolysis and dehydration condensation reaction. In this case, -M-OM- (here , M is a metal element, and O is an oxygen element), a chemically strong three-dimensional bond network is formed and cannot be solated again. Once gelled, it can be processed by means such as coating. Can not. On the other hand, in a method of obtaining a composite gel by reacting a metal oxide precursor in a solution containing the metal oxide precursor and a compound that interacts with the metal oxide precursor, By utilizing the interaction property of the compound that interacts with the body, it can be made into a sol again and can have excellent processability.

Here, examples of the metal oxide precursor include metal compounds such as metal halides, metal complex compounds, metal alkoxides, metal carboxylates, and chelate compounds that are soluble in the solvent used. Specific examples of the compound include metals such as TiCl ₄ (titanium tetrachloride), ZnCl ₂ (zinc chloride), WCl ₆ (tungsten hexachloride), SnCl ₂ (stannous chloride), and SrCl ₆ (strontium chloride). Halides, Ti (NO ₃ ) ₄ (titanium nitrate), Zn (NO ₃ ) ₂ (zinc nitrate), nitrates such as Sr (NO ₃ ) ₂ (strontium nitrate), and the general formula M (OR) n (however, M is a metal element, R is an alkyl group, and n is an oxidation number of the metal element.).

  Examples of the metal alkoxide include zinc diethoxide, tungsten hexaethoxide, vanadyl ethoxide, tin tetraisopropoxide, strontium diisopropoxide, and the like.

  For example, when forming a metal oxide layer of titanium oxide, examples of the metal alkoxide include titanium tetraisopropoxide, titanium tetranormal propoxide, titanium tetraethoxide, titanium tetranormal butoxide, titanium tetraisobutoxide, and titanium tetra. Tertiary butoxide and the like can be preferably used.

  Examples of the functional group that interacts with the metal oxide precursor include a carboxyl group, an amino group, and a hydroxyl group. Moreover, as a functional group which interacts with a metal oxide precursor, you may have 1 or more types of the said functional groups like an amic acid structure. The compound having at least one functional group that interacts with the metal oxide precursor is a compound having at least one functional group selected from a carboxyl group, an amino group, a hydroxyl group, and an amino acid structure. Particularly preferred are polymer compounds. Specific examples of such a low molecular weight compound include dicarboxylic acid, diamine, diol, diamic acid and the like.

  Specific examples of the polymer compound include a polymer compound having at least one functional group selected from a carboxyl group, an amino group, a hydroxyl group, and an amic acid structure in the main chain, side chain, or cross-linked portion. The main chain structure of the polymer compound is not particularly limited, but a polyethylene structure, a polystyrene structure, a polyacrylate structure, a polymethacrylate structure, a polycarbonate structure, a polyester structure, a cellulose structure, Examples thereof include a silicone structure, a vinyl polymer structure, a polyamide structure, a polyamideimide structure, a polyurethane structure, a polyurea structure, etc., or an arbitrary structure such as a copolymer structure.

Furthermore, as a polymer compound having at least one functional group selected from the carboxyl group, amino group, hydroxyl group, and amic acid structure in the main chain, side chain, or cross-linked portion, the polymer compound interacts with the metal oxide precursor. From the viewpoint of suitable form, the use of polyacrylic acid having a carboxyl group in the side chain is particularly preferred.
The polymer compound having one or more functional groups that interact with the metal oxide precursor is a polymer compound having a functional group that interacts with the carboxyl group, the amino group, the hydroxyl group, or the amic acid structure. It may be a copolymer with a polymer compound having the same main chain structure. The polymer compound having at least one functional group that interacts with the metal oxide precursor has a mixed system of two or more, or a carboxyl group, an amino group, a hydroxyl group, and an amic acid structure, depending on the purpose. A mixed system with a polymer compound having a main chain structure similar to that described above may be used. The average degree of polymerization of the polymer compound having one or more functional groups that interact with the metal oxide precursor is preferably 100 to 10000000, more preferably 5000 to 250,000.

  As the solvent, alcohols such as methanol, ethanol, isopropanol and butanol, and metal oxide precursors such as formamide, dimethylformamide, dioxane and benzene can be dissolved and do not react with the metal oxide precursor. Can be used.

  Hereinafter, the method for forming a semiconductor nanoporous layer will be described in detail by taking as an example the case of using a metal alkoxide as the metal oxide precursor.

First, the metal alkoxide is added to the solvent (for example, an organic solvent such as alcohol). Further, water necessary for partially hydrolyzing the metal alkoxide and an acid such as hydrochloric acid, nitric acid, sulfuric acid or acetic acid are added as a catalyst. The amount of water and acids added here can be appropriately selected according to the degree of hydrolyzability of the metal alkoxide used.
Next, the obtained mixed solution is heated or refluxed at room temperature (for example, 25 ° C., hereinafter, the same applies to room temperature) to 150 ° C., preferably at room temperature to 100 ° C. in a dry nitrogen stream while stirring. The reflux temperature and time can also be appropriately selected according to the hydrolyzability of the metal oxide precursor used.
As a result of the reflux, the metal alkoxide is partially hydrolyzed. That is, since the amount of the water contained in the mixed solution is small enough not to sufficiently hydrolyze the alkoxyl group of the metal alkoxide, the metal represented by the general formula: M (OR) _n In alkoxides, all of the —OR groups are not hydrolyzed, resulting in a partially hydrolyzed state. In the partially hydrolyzed metal alkoxide, the polycondensation reaction does not proceed. For this reason, even if the chain | strand of -MOMM is formed between the said metal alkoxides, the said metal alkoxide will be in an oligomer state. The mixed solution after reflux containing the metal alkoxide in the oligomer state is colorless and transparent and hardly increases in viscosity.

  Next, the temperature of the mixed solution after reflux is lowered to room temperature, and the mixed solution is a polymer compound (preferably a polyvalent compound having at least one functional group selected from a carboxyl group, an amino group, a hydroxy group, and an amino acid structure). (Acrylic acid) is added. In this case, the polymer compound that is originally difficult to dissolve in an organic solvent such as alcohols is easily dissolved in the mixed solution to obtain a transparent sol. This is considered to be because the carboxyl group of the polymer compound and the metal alkoxide are bonded by a salt formation reaction to form a polymer complex compound. This transparent sol is usually a colorless and transparent uniform solution.

  By adding an excessive amount of water to the transparent sol and maintaining the reaction at room temperature to 150 ° C., preferably about room temperature to 100 ° C., the reaction is continued for several minutes (for example, 5 minutes) to about 1 hour. The transparent sol is gelled to form a composite gel having a crosslinked structure of the polymer compound and the metal alkoxide.

  When the resulting composite gel is further maintained at room temperature to 90 ° C. (usually about 80 ° C.) for 5 to 50 hours and the reaction is continued, the composite gel is dissolved again to obtain a translucent metal oxide fine particle colloidal dispersion sol. . This is because the polycondensation reaction proceeds due to the hydrolysis reaction of the metal alkoxide, and the salt structure of the polymer compound and the metal alkoxide is decomposed to change into metal oxide fine particles and carboxylic acid esters. Is due to.

  The semitransparent metal oxide fine particle colloidal dispersion sol obtained as described above is applied to an electrode layer provided on a substrate, and then dried or baked to form a metal oxide film having fine pores.

  The coating method can be performed by a known method without any particular limitation. Specific examples include a dip coating method, a spin coating method, a wire bar method, and a spray coating method. In addition, for example, air drying, drying using an oven or the like, and vacuum freeze drying are possible for drying. Moreover, the method of evaporating a solvent using apparatuses, such as a rotary evaporator, may be used. In this case, the drying temperature, time, etc. can be appropriately selected according to the purpose.

  Further, the polymer compound or the reaction product thereof may not be removed only by drying the metal oxide fine particle colloidal dispersion sol at a drying temperature and removing the liquid component containing the solvent. In such a case, it is preferable to perform firing in order to remove these further to obtain a pure metal oxide. The firing can be performed using, for example, a furnace, and the firing temperature varies depending on the type of the polymer compound having the functional group used, but a low temperature is suitable for multi-layering. About 100 ° C to 700 ° C is preferable, and 100 ° C to 400 ° C is more preferable.

  The firing causes crystallization of the metal oxide fine particles and sintering of the metal oxide fine particles, and at the same time, the organic polymer component is thermally decomposed and disappears.

  In the formation of the semiconductor nanoporous layer, the formation reaction of metal oxide fine particles proceeds in a composite gel in which diffusion is regulated, so that formation of coarse particles, aggregation due to sedimentation of particles does not occur, and the like. A metal oxide fine particle colloidal dispersion sol in which small ultrafine particles are uniformly dispersed can be obtained.

  Regarding the size of the metal oxide fine particles of the semiconductor nanoporous layer, the period of the metal oxide fine particle aggregate structure, the volume ratio of the metal oxide fine particle aggregate phase and the void phase, etc., for example, relative to the metal oxide precursor The addition amount of the compound having at least one functional group that interacts with the metal oxide precursor is combined with the compound having at least one functional group that interacts with the metal oxide precursor and the metal oxide precursor. The ratio of the solid component to the whole mixed solution can be controlled to a desired level.

  That is, when the addition amount of the compound having one or more functional groups to be fired with the metal oxide precursor is increased, the volume ratio of the void phase in the obtained semiconductor nanoporous layer is increased, and the metal oxide precursor and the metal oxide are oxidized. If the ratio of the solid component combined with the compound having at least one functional group that interacts with the precursor of the compound to the whole mixed solution is reduced, the cycle of the resulting metal oxide fine particle aggregated structure becomes smaller, and the density of the void phase However, the size of the metal oxide fine particles themselves increases.

  The addition amount of the compound having one or more functional groups that interact with the metal oxide precursor with respect to the metal oxide precursor can be appropriately selected depending on the ratio of the solid component to the whole mixed solution, In general, the mass ratio is preferably 0.1 to 1, and more preferably 0.2 to 0.8. By setting it as such a range, it is possible to more effectively prevent the formation of a large three-dimensional network of -M-OM- and hinder the re-dissolution of the composite gel, and the dense semiconductor nanometer with few macropores. Make the porous layer easier. On the other hand, if the addition amount is increased to exceed 1, relatively large voids are generated, and a transparent semiconductor nanoporous layer tends to be formed.

  The ratio of the solid component to the entire mixed solution can be appropriately selected because it varies depending on the amount of the metal oxide precursor and the compound having one or more functional groups that interact with the metal oxide precursor. However, generally 1-10 mass% is preferable and 2-5 mass% is more preferable. When the proportion is less than 1% by mass, the progress of the complex gelation reaction is slow, and metal oxide fine particles are formed in a transparent sol state with high fluidity, and coarse particles are formed, whereas 10% by mass. If it exceeds 50%, the progress from the transparent sol to the composite gel is fast, and a uniform composite gel may not be obtained.

  Below, the case where tungsten hexaethoxide is used as the metal alkoxide is taken as an example, and the method for forming the tungsten oxide porous layer will be described in more detail.

  First, tungsten hexaethoxide is added to alcohol to prepare a mixed solution. In this case, water and an acid as a catalyst are added to the alcohol, and the water is preferably 0.1 mole to equimolar to tungsten hexaethoxide, and the acid is tungsten hexaethoxide. The molar amount is preferably 0.05 times to 0.5 times mol. The resulting mixed solution is refluxed under a stream of dry nitrogen with stirring, for example, at room temperature to 80 ° C. The reflux temperature and time here are preferably about 30 minutes to 3 hours at 80 ° C. As a result of this reflux, a transparent mixed solution is obtained.

  In this mixed solution, tungsten hexaethoxide is partially hydrolyzed and is in an oligomer state. The temperature of the mixed solution is lowered to room temperature and polyacrylic acid is added. Polyacrylic acid, which is essentially insoluble in alcohol, dissolves easily in this mixed solution, and a colorless transparent sol is obtained. This is because the carboxylic acid of polyacrylic acid and tungsten hexaethoxide are bonded by a salt formation reaction to form a polymer complex compound. When an excessive amount of water is further added to this transparent sol and kept at room temperature to 80 ° C., the transparent sol gels in about several minutes to 1 hour, and a composite of a crosslinked structure containing at least polyacrylic acid and tungsten hexaethoxide Gelation is formed.

  When this composite gel is held at about 80 ° C. for 5 to 50 hours, the composite gel is dissolved again to obtain a translucent sol. This is because the hydrolysis and polycondensation reaction of tungsten hexaethoxide proceeds, and the salt structure of polyacrylic acid and tungsten hexaethoxide decomposes to change into titanium oxide and carboxylic acid ester. .

  The obtained sol solution is applied to a suitable substrate by a dip coating method or the like and heated to a high temperature of about 100 ° C. to 600 ° C. With this heating, crystallization of tungsten oxide fine particles and sintering between the tungsten oxide fine particles proceed, and at the same time, the polymer phase is thermally decomposed to form film-like tungsten oxide fine particles in which tungsten oxide is aggregated in a phase separated state. It becomes.

  The amount of polyacrylic acid relative to tungsten hexaethoxide is preferably 0.3 to 0.7 by weight. By setting the mass ratio to 0.3 or more, it is possible to prevent the case where the gel does not dissolve due to the formation of a large three-dimensional network of -MOMM, and to 0.7 or less. It is possible to more effectively prevent a relatively large void from being formed and forming a transparent layer.

  Moreover, as a ratio with respect to the said whole mixed solution of the solid component of tungsten hexaethoxide and polyacrylic acid, 1-10 mass% is preferable. By making the ratio 1% by mass or more, the progress of the composite gelation reaction is slow, and tungsten oxide fine particles can be formed in a highly fluid sol state, so that coarse tungsten oxide fine particles can be formed more effectively. Can be prevented. On the other hand, when the content is 10% by mass or less, the case where a uniform composite gel cannot be obtained with a rapid progress from the transparent sol to the composite gel can be more unlikely to occur.

(Method for forming compound semiconductor nanoporous layer)
Examples of the method for forming the compound semiconductor nanoporous layer include (1) electrolytic deposition, (2) chemical bath deposition, and (3) photochemical deposition, and are specifically described below.

(1) Electrolytic Deposition Method The electrolytic deposition method includes an electrode in which a transparent conductive film on a transparent insulating substrate is formed in an electrolyte containing at least ions of elements to be deposited, and an electrode facing the electrode. It arrange | positions and raise | generates an oxidation-reduction reaction electrochemically between these electrodes, The said compound semiconductor layer is formed on the electrode in which the transparent conductive film was formed. “Surface Technology” Vol. 49, no. See pages 1, 3 and 1998.

(2) Chemical bath deposition method In the chemical bath deposition method, an electrode on which a transparent conductive film is formed on a transparent insulating substrate is placed in a solution containing at least one kind of deposited ions, and the temperature of the solution is adjusted. And the ion concentration adjustment causes a reduction reaction to form the compound semiconductor layer on the electrode. “Journal of Applied Physics” vol. 82, 2, 655, 1997.

(3) Photochemical deposition method In the photochemical deposition method, an electrode in which a transparent conductive film is formed on a transparent insulating substrate is placed in a solution containing at least one kind of sodium thiosulfate and metal ions, and ultraviolet rays are applied to the electrode. Irradiation causes a photoreaction, and the compound semiconductor layer is formed on the electrode. Reference can be made to “Japan Journal Applied Physics” vol 36, L 1146, 1997.

(Formation method of composite oxide semiconductor nanoporous layer)
The composite oxide semiconductor nanoporous layer is a method in which an oxide semiconductor nanoporous layer is further formed by a sol-gel method on the oxide semiconductor nanoporous layer formed by the above method, or two types of composites are formed. Examples thereof include a method of applying a paste mixed with oxide semiconductor particles on an electrode.

  Specifically, acetic acid is dropped into an aqueous oxide semiconductor colloid solution, and the oxide semiconductor powder and alcohol to be combined are added little by little to the gel solution mixed well in a mortar and mixed well. Further, a surfactant is added and mixed well, and this is spray-coated on a hot plate (100 to 120 ° C.) on a fluorine-doped tin oxide conductive film glass (FTO) electrode and baked, thereby producing semiconductor fine particles. Crystallization and firing of semiconductor fine particles proceed to form a composite oxide semiconductor nanoporous layer having a desired porosity.

(EC dye)
The EC dye is preferably supported on the surface and internal micropores of the semiconductor nanoporous layer and, if necessary, contained in a dissolved or dispersed state in the electrolyte layer.
The EC dye is not particularly limited as long as it exhibits an effect of developing or erasing black by at least one of an electrochemical oxidation reaction and a reduction reaction, and can be appropriately selected according to the purpose. For example, an organic dye And metal complex dyes are preferred, and organic dyes are preferred. These EC dyes may be used alone or in combination of two or more.

  Examples of the metal complex dye include Prussian blue, metal-bipyridyl complex, metal phenanthroline complex, metal-phthalocyanine complex, metaferricyanide, and derivatives thereof.

  Examples of the organic dye include (1) pyridine compounds, (2) conductive polymers, (3) styryl compounds, (4) donor / acceptor type compounds, (5) other organic dyes, Etc.

  Examples of the (1) pyridine compounds include viologen, heptyl viologen (diheptyl viologen dibromide, etc.), methylenebispyridinium, phenanthroline, azobipyridinium, 2,2-bipyridinium complex, quinoline / isoquinoline, and the like.

  Examples of the conductive polymer (2) include polypyrrole, polythiophene, polyaniline, polyphenylenediamine, polyaminophenol, polyvinylcarbazole, polymer viologen polyion complex, TTF, and derivatives thereof.

  Examples of the (3) styryl compounds include 2- [2- [4- (dimethylamino) phenyl] ethenyl] -3,3-dimethylindolino [2,1-b] oxazolidine, 2- [4- [4- (Dimethylamino) phenyl] -1,3-butadienyl] -3,3-dimethylindolino [2,1-b] oxazolidine, 2- [2- [4- (dimethylamino) phenyl] ethenyl]- 3,3-dimethyl-5-methylsulfonylindolino [2,1-b] oxazolidine, 2- [4- [4- (dimethylamino) phenyl] -1,3-butadienyl] -3,3-dimethyl-5 -Sulfonylindolino [2,1-b] oxazolidine, 3,3-dimethyl-2- [2- (9-ethyl-3-carbazolyl) ethenyl] indolino [2,1-b] oxazolidine 2- [2- [4- (acetylamino) phenyl] ethenyl] -3,3-dimethyl-indolino [2,1-b] oxazolidine, and the like.

  Examples of the (4) donor / acceptor type compounds include tetracyanoquinodimethane and tetrathiafulvalene.

  Examples of (5) other organic dyes include carbazole, methoxybiphenyl, anthraquinone, quinone, diphenylamine, aminophenol, Tris-aminophenylamine, phenylacetylene, cyclopentyl compound, benzodithiolium compound, squalium salt, cyanine, rare earth Examples include phthalocyanine complexes, ruthenium diphthalocyanines, merocyanines, phenanthroline complexes, pyrazolines, redox indicators, pH indicators, and derivatives thereof.

  Further, as the EC dye, a reduction coloring type that shows colorless or ultra-light color in the oxidation state and develops color in the reduction state, an oxidation coloring type that shows colorless or ultra-light color in the reduction state and develops color in the oxidation state, It may be any of the multicolor coloring types that exhibit color development in the reduced state or the oxidized state, and develop several kinds of colors depending on the degree of reduction or oxidation, and can be appropriately selected according to the purpose.

  In the EC dye, a combination of coloring and decoloring black by oxidation-reduction reaction is 2- {2- [4- (dimethylamino) phenyl] ethenyl} -3, 3-dimethyl-5-phosphonoindolino [2,1-b] oxazoline and 2- {2- [4- (dimethylamino) phenyl] -1,3-butadienyl} -3,3-dimethyl-5 Carboxyindolino [2,1-b] oxazoline and 2- {2- [4- (methoxy) phenyl] ethenyl} -3,3-dimethyl-5-phosphonoindolino [2,1-b] oxazoline Combination, etc. are mentioned. Examples of the combination of reducing coloring dyes include a combination of bis- (2-phosphonoethyl) -4,4'-bipyridinium dibromide and [β- (10-phenothiazyl) propoxy] phosphonic acid.

  There is no restriction | limiting in particular as a method to carry | support EC pigment | dye on the surface and the inside of the said semiconductor nanoporous layer, A well-known technique can be used. For example, a dry process such as a vacuum deposition method, a coating method such as spin coating, an electric field deposition method, an electric field polymerization method, or a natural adsorption method in which a solution of a compound to be supported is immersed can be appropriately selected. Above all, the natural adsorption method does not require special equipment that can support functional molecules evenly throughout the fine pores of the metal oxide layer and does not require special equipment. It has many advantages such as no extra amount and is a preferred method.

  Specifically, a method of immersing a transparent substrate having a well-dried semiconductor nanoporous layer in an EC dye solution or applying a dye solution to the semiconductor nanoporous layer can be used. In the former case, an immersion method, a dip method, a roller method, an air knife method or the like can be used. In the case of the dipping method, the dye may be adsorbed at room temperature, or may be carried out by heating and refluxing as described in JP-A-7-249790. Examples of the latter application method include a wire bar method, a slide hopper method, an extrusion method, a curtain method, a spin method, and a spray method.

  Examples of the solvent for dissolving the EC dye include water, alcohols (methanol, ethanol, t-butanol, benzyl alcohol, etc.), nitriles (acetonitrile, propionitrile, 3-methoxypropionitrile, etc.), nitromethane, Halogenated hydrocarbons (dichloromethane, dichloroethane, chloroform, chlorobenzene, etc.), ethers (diethyl ether, tetrahydrofuran, etc.), dimethyl sulfoxide, amides (N, N-dimethylformamide, N, N-dimethylacetamide, etc.), N -Methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, esters (ethyl acetate, butyl acetate, etc.), carbonates (diethyl carbonate, ethylene carbonate, propylene carbonate, etc.), ketones (acetone, 2 − Thanong, cyclohexanone), hydrocarbons (hexane, petroleum ether, benzene, toluene, etc.) or mixed solvents thereof.

The adsorption amount of the EC dye is preferably 0.01 to 100 mmol per unit surface area (1 m ² ) of the semiconductor nanoporous layer, for example. Further, the adsorption amount of the EC dye to the semiconductor fine particles is preferably in the range of 0.01 to 100 mmol per 1 g of the semiconductor fine particles. The concentration of the EC dye in the electrolyte is preferably 0.001 to 2 mol / l, and more preferably 0.005 to 1 mol / l.
Therefore, the EC dye is included in the semiconductor nanoporous layer is intended to include the case where the EC dye is applied to the surface of the semiconductor nanoporous layer.
Of course, the EC dye of the present invention is not necessarily included in the semiconductor nanoporous layer, and may be included in other layers as long as it does not depart from the spirit of the present invention.

(Charge transfer agent)
Like the EC dye, the charge transfer agent is preferably supported on the surface and internal micropores of the semiconductor nanoporous layer and contained in a state dissolved or dispersed in the electrolyte layer or the photoconductive layer. . The charge transfer agent can be supported on the semiconductor nanoporous layer by the same method as for EC dyes. By using the charge transfer agent and the EC dye in combination, a redox reaction proceeds smoothly due to the color-adding effect by the simultaneous color development of both, and the interaction between the two, and the color development efficiency is further improved.

  The charge transfer agent is not particularly limited and may be appropriately selected depending on the intended purpose. However, those exhibiting electrochromic properties are suitable, and examples thereof include hydrazone and phenothiazine. It can use individually or in combination of 2 or more types.

The amount of adsorption of the charge transfer agent is preferably 0.01 to 100 mmol per unit surface area (1 m ² ) of the semiconductor nanoporous layer, for example. The amount of charge transfer agent adsorbed on the semiconductor fine particles is preferably in the range of 0.01 to 100 mmol per gram of semiconductor fine particles. The concentration of the charge transfer agent in the electrolyte is preferably 0.001 to 2 mol / l, and more preferably 0.005 to 1 mol / l.

<Photoconductive layer>
The image display device of the present invention preferably includes a photoconductive layer, and the photoconductive layer includes, for example, a charge generation layer containing a charge generation agent and a charge transport layer containing a charge transfer agent. In addition, it is possible to perform optical writing display using light having a wavelength shorter than that required for the charge generating agent contained in the photoconductive layer to generate a charge or cause a current multiplication phenomenon. The conductivity of the photoconductive layer is preferably changed by visible light.

(Charge generator)
The charge generating agent is made of a photoconductor that is an inorganic semiconductor such as c-Si (crystalline silicon), a-Se (amorphous selenium), or a-SiC (amorphous silicon carbide). The photoconductive layer may be made of a photoconductor that doubles carriers generated in the photoelectric conversion process by a current amplification mechanism.
The photoconductive layer may use another organic photoconductor. In this case, since a current multiplication phenomenon (photo-induced electron injection) other than the avalanche effect seen in inorganic silicon semiconductors can be obtained, the photoconductive layer is preferably composed mainly of an organic photoconductor. As this organic photoconductor, a perylene pigment, a quinaclide pigment, a naphthalene tetracarboxylic acid derivative, etc. can be mentioned, for example.
Specific examples of charge generating materials for organic photoconductors include benzimidazole perylene (BZP), quinacridone, and naphthalenetetracarboxylic acid.

(Charge transport agent)
Charge transport agents include, for example, carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone Derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidene compounds, porphyrin compounds, polysilane compounds, poly (N-vinylcarbazole) derivatives, aniline polymers , Conductive polymer oligomers such as thiophene oligomers and polythiophenes, and diene compounds.

<Electrolyte layer>
The electrolyte layer is not particularly limited and can be appropriately selected depending on the purpose, but preferably contains an EC dye and / or a charge transfer agent, and the EC dye and the charge transfer agent include those described above. However, it is preferable to use the same EC dye or charge transfer agent supported on the semiconductor nanoporous layer. The electrolyte layer may be any of (1) liquid, (2) solid, and (3) gel.

(1) In the case of a liquid electrolyte layer, when the electrolyte layer is a liquid, it includes redox pairs (redox couples) such as I− / I ³⁻ , Br ⁻ / Br ³⁻ , quinone / hydroquinone pairs, It is preferable to use a charge transporting substance such as an electrolyte that can be transported at a sufficient speed in a solvent.

As the electrolyte, for example, iodine, bromine, LiI, NaI, KI, CsI , CaI 2, LiBr, NaBr, KBr, CsBr, metal halides such as CaBr _2, tetraethylammonium iodide, tetrapropylammonium iodide Halogenated salts of ammonium compounds such as tetrabutylammonium bromide, tetramethylammonium bromide, tetraethylammonium bromide and tetrabutylammonium bromide, alkyl viologens such as methyl viologen chloride and hexyl viologen bromide, polyhydroxy such as hydroquinone and naphthohydroquinone At least one of iron complexes such as benzene, ferrocene, and ferrocyanate can be used, but is not limited thereto.
In addition, when a plurality of electrolytes that generate redox pairs (redox pairs) in advance, such as a combination of iodine and lithium iodide, are used, it is possible to improve the performance of the EC element, particularly the current characteristics. Become. Among these, a combination of iodine and an ammonium compound, iodine and a metal iodide, and the like are preferable.

  Solvents for dissolving these electrolytes include carbonate compounds such as ethylene carbonate and propylene carbonate, ethers such as dioxane, diethyl ether and ethylene glycol dialkyl ether, methanol, ethanol, isopropyl alcohol, ethylene glycol, propylene glycol, polyethylene glycol and the like Alcohols, nitriles such as acetonitrile and benzonitrile, aprotic polar solvents such as dimethylformamide, dimethyl sulfoxide, propylene carbonate and ethylene carbonate, water, and the like can be used, but are not limited thereto.

  The electrolyte concentration of the electrolyte in the solvent is preferably 0.001 to 2 mol / L, and more preferably 0.005 to 1 mol / L. By setting the electrolyte concentration to 0.001 mol or more, the function as a carrier can be more effectively maintained and the characteristics can be sufficiently maintained. On the other hand, by setting it to 2 mol / L or less, the function as a carrier can be maintained more effectively, the viscosity of the electrolyte solution can be prevented from becoming too high, and a decrease in current can be more effectively suppressed.

(2) In the case of a solid electrolyte layer When the electrolyte layer is solid, it may be any substance exhibiting ionic conductivity or electronic conductivity, for example, AgBr, AgI, CuCl, CuBr, CuI, LiI. _{, LiBr, LiCl, LiAlCl 4,} LiAlF 4, halides _{etc., AgSBr, C 5 H 5 NHAg} 5 I 6, Rb 4 Cu1 6 I 7 Cl 13, Rb 3 Cu 7 Cl 10 and the like of the inorganic Fukushio, LiN, Lithium nitride such as Li ₅ NI ₂ , Li ₆ NBr ₃ and derivatives thereof, lithium oxyacid salts such as Li ₂ SO ₄ , Li ₄ SiO ₄ , Li ₃ PO ₄ , ZrO ₂ , CaO, Gd ₂ O ₃ , HfO ₂ , Y ₂ O ₃ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , oxides such as these solid solutions, CaF ₂ , PbF ₂ , SrF ₂ , LaF ₃ , TISn ₂ F ₅ , CeF _3, etc. Fluoride, Cu Chalcogenides such as ₂ S, Ag ₂ S, Cu ₂ Se, AgCrSe ₂ , polymers containing perfluorosulfonic acid in vinyl fluoride polymers (for example, Nafion), polythiophene, polyaniline, polypyrrole as organic charge transport materials And the like, aromatic amine compounds such as triphenylamine, carbazole compounds such as polyvinyl carbazole, and silane compounds such as polymethylphenylsilane are not limited thereto.

(3) In the case of a gel electrolyte layer, when the electrolyte layer is in a gel form, polymer addition, oil gelling agent addition, and polyfunctional monomers can be mixed and used in the electrolyte and the solvent. In the case of gelation by adding the polymer, a compound described in “Polymer Electrolyte Revues-1 and 2” (JR MacCallum and CA Vincent co-edit, ELSEVIER APPLIED SCIENCE) may be used. In particular, polyacrylonitrile, polyvinylidene fluoride, and the like are suitable. In the case of gelation by addition of the oil gelling agent, “J. Chem Soc. Japan, Ind. Chem. Sec., 46, 779 (1943)”, “J. Am. Chem. Soc., 111, 5542 (1989). ) "," J. Chem. Soc., Chem. Commun., 1993, 390 "," Angew. Chem. Int. Ed. Engl., 35, 1949 (1996) "," Chem. Lett., 1996, 885 ". "," J. Chem. Soc., Chem. Commun., 1997, 545 "and the like can be used. In particular, compounds having an amide structure in the molecular structure are preferred.

(4) A solid electrolyte layer formed by polymerizing a mixed solution of a matrix material and a supporting electrolyte to form a film can also be used.

(Supporting electrolyte)
There is no restriction | limiting in particular as said supporting electrolyte, According to the objective, it can select suitably, An inorganic electrolyte may be sufficient and an organic electrolyte may be sufficient. These may be used individually by 1 type, may use 2 or more types together, may be a commercial item, and may synthesize | combine suitably.

  Examples of the inorganic electrolyte include inorganic acid anions-alkali metal salts, alkali metal salts, alkaline earth metals, etc. Among these, inorganic acid anions-alkali metal salts are preferable, and inorganic acid lithium salts are more preferable. preferable.

Examples of the inorganic acid anion-alkali metal salt include XAsF ₆ , XPF ₆ , XBF ₄ , XClO ₄ , etc. (where X represents H, Li, K, or Na). Specifically, lithium perchlorate and the like are preferable.

Examples of the alkali metal salt include LiI, KI, LiCF ₃ SO ₃ , LiPF ₆ , LiClO ₄ , LiBF ₄ , LiSCN, LiAsF ₆ , NaCF ₃ SO ₃ , NaPF ₆ , NaClO ₄ , NaI, NaBF ₄ , NaAsF _6. , KCF ₆ SO ₃ , KPF ₆ , and the like.

  Examples of the organic electrolyte include organic acid anion-alkali metal salts, quaternary ammonium salts, anionic surfactants, imidazolium salts, etc. Among these, organic acid anions-alkali metal salts are preferable. An organic acid lithium salt is more preferable.

Examples of the organic acid anion-alkali metal salt include XCF ₃ SO ₃ , XC _n F _{2n + 1} SO ₃ (n = 1 to 3), XN (CF ₃ SO ₂ ) ₂ , XC (CF ₃ SO _2). ) ₃ , XB (CH ₃ ) ₄ , XB (C ₆ H ₅ ) ₄ , etc. (in which X represents H, Li, K or Na), specifically, polymethacrylic acid Preferred examples include lithium.

Examples of the quaternary ammonium salt include [CH ₃ (CH ₂ ) ₃ ] ₄ N · Y, C _n H _{2n + 1} N (CH ₃ ) ₃ · Y (n = 10 to 18), (C _n H _{2n + 1} ) ₂ N (CH ₃ ) ₂ · Y (n = 10 to 18), etc. (in which Y represents BF ₄ , PF ₆ , ClO ₄ , F, Cl, Br or OH). To express.)

Examples of the anionic surfactant include C _n H _{2n + 1} COO · X (n = 10 to 18), C _n H _{2n + 1} OC _m H _2m COO · X (n = 10 to 18, m = _{10~18), C 10 H 7 COO} · X, C n H 2n + 1 C 10 H 6 COO · X (n = 10~18), C n H 2n + 1 SO 3 · X (n = 10~18 _{), C n H 2n + 1} OC m H 2m SO 3 · X (n = 10~18, m = 10~18), C 10 H 7 SO 8 · X, C n H 2n + 1 C 10 H 6 SO _{3 · X (n = 10~18)} , C n H 2n + 1 OSO 3 · X (n = 10~18), and the like (however, X in these represents H, Li, K or Na .)

  In particular, the supporting electrolyte preferably contains an inorganic acid lithium salt and an organic acid lithium salt.

(Matrix material)
There is no restriction | limiting in particular as said matrix material, According to the objective, it can select suitably, For example, the high molecular compound which has a hetero atom, etc. are mentioned.

  Examples of the polymer compound having a hetero atom include a polymer compound having an oxygen atom, a polymer compound having a nitrogen atom, a polymer compound having a sulfur atom, and a polymer compound having a halogen atom.

Examples of the polymer compound having an oxygen atom include R ¹ — (OCH ₂ CH ₂ ) _n O—R ^2, where n represents an integer, and R ¹ represents an ethylene group, a styrene group, a propylene group, or a butene group. Represents a butadiene group, a vinyl chloride group, a vinyl acetate group, an acrylic acid group, a methyl acrylate group, a methacrylic acid group, a methyl methacrylate group, a methyl vinyl ketone group, an acrylamide group or the like, and R ² represents H, CH ₃ or And a compound represented by R ^1. ), Specifically, polyethylene glycol, polypropylene glycol, non-polyethers (for example, poly (3-hydroxypropionic acid), polyvinyl acetate), Etc. are preferable.

Examples of the polymer compound having a nitrogen atom include R ¹ — (NHCH ₂ CH ₂ ) _n NH—R ² (n represents an integer, and R ¹ represents an ethylene group, a styrene group, a propylene group, or a butene group. Represents a butadiene group, a vinyl chloride group, a vinyl acetate group, an acrylic acid group, a methyl acrylate group, a methacrylic acid group, a methyl methacrylate group, a methyl vinyl ketone group, an acrylamide group or the like, and R ² represents H, CH ₃ or R ¹ represents a compound represented by R ¹ ), and specific examples thereof include polyethyleneimine, poly-N-methylethyleneimine, polyacrylonitrile, and the like.

Examples of the polymer compound having a sulfur atom include R ¹ — (SCH ₂ CH ₂ ) _n S—R ² (n represents an integer, and R ¹ represents an ethylene group, a styrene group, a propylene group, or a butene group. Represents a butadiene group, a vinyl chloride group, a vinyl acetate group, an acrylic acid group, a methyl acrylate group, a methacrylic acid group, a methyl methacrylate group, a methyl vinyl ketone group, an acrylamide group or the like, and R ² represents H, CH ₃ or R ¹ represents a compound represented by R ¹ ), and specific examples thereof include polyalkylene sulfides.

  The molecular weight of the matrix material is not particularly limited and can be appropriately selected according to the purpose.However, since the lower one often has fluidity at room temperature, the lower one is preferable from the viewpoint of film forming property. The number average molecular weight is preferably 1000 or less.

  The amount of the matrix material used in the electrolyte layer is preferably such that the molar ratio to the supporting electrolyte (matrix material: supporting electrolyte) is 70:30 to 5:95, and is 50:50 to 10:90. More preferably, it is particularly preferably 50:50 to 20:80.

  The molar ratio means the ratio between the molar amount of the matrix material and the molar amount of ions of the supporting electrolyte. The molar amount of the matrix material means a molar amount in which the monomer unit of the polymer compound is converted into one molecule.

  The film-like solid electrolyte layer is thinly stretched by adding a small amount of a polymerization initiator such as benzoyl peroxide or azobisisobutyronitrile to the mixed solution of the matrix material and the supporting electrolyte, followed by heating for polymerization. Alternatively, it can be prepared by adding a photopolymerization initiator such as Irgacure and polymerizing by irradiation with ultraviolet rays. In addition, the thickness of a solid electrolyte film becomes like this. Preferably it is 30-500 micrometers, More preferably, it is 50-200 micrometers.

<Optical writing display device>
Preferred embodiments of an optical writing display element and an optical writing display device according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a conceptual diagram showing an optical writing display device according to a first embodiment of the present invention. As shown in FIG. 1, the optical writing display device 1 according to the present embodiment includes a writing display board 3 and a writing device 5. As shown in FIG. 2, the writing display board 3 has an optical writing display element 7 that develops different colors.

  The optical writing display element 7 according to the embodiment of FIG. 2 is formed by laminating three types of electrochromic display bodies (EC display bodies) 7a, 7b, and 7c. Each of the EC display bodies 7a, 7b, and 7c generates yellow (Y), magenta (M), and cyan (C), which are the three primary colors. In this embodiment, a configuration for bright full-color display is adopted. However, the optical writing display element according to the present invention may have a configuration other than the three layers of the EC display, and develop any color other than YMC. Alternatively, an EC display may be used.

  As an image forming method, a method of obtaining a desired pattern by distributing the amount of light to be irradiated is preferable. In the embodiment of FIG. 2, Y, M, and C are sequentially provided with a distribution of irradiation light and colored in a desired pattern, thereby enabling full color display.

A reflective film 9 is laid on one surface of the writing display board 3 (the lower surface side in FIG. 2). The reflection film 9 is transparent to the writing light 11, but can reflect light having a wavelength other than the writing light 11.
The writing light 11 at this time is particularly limited as long as it is light having a wavelength shorter than that required for generating a charge by the charge generating agent of the photoconductive layer or causing a current multiplication phenomenon, for example. However, infrared light (IR), visible light, ultraviolet light (UV), or the like can be used, but it is preferable to use visible light from the viewpoint of performance, versatility, and cost of the organic photoconductive material. In particular, it is preferable to perform writing with light of 410 nm or more and 700 nm or less using an image display device having a layer containing a fluorescent brightening agent that absorbs 90% or more of light of 200 nm or more and 410 nm or less.
As the reflective film 9, a multilayer interference filter, a half mirror, or the like can be suitably used. In the case where the writing display board 3 is displayed by transmitted light, the reflection film 9 may be omitted.

Next, a more detailed configuration of the EC display will be described.
As shown in FIG. 3, each layer of the EC display 7a (or 7b, 7c) stacked for each color is provided on the photoconductive layer 15a (or 15b, 15c) and the photoconductive layer 15a. An electrochromic layer (EC layer) 17, an electrolyte layer 19 provided on the EC layer 17, and a pair of first electrode layer (front electrode) 13 a and second electrode layer (back electrode) 13 b sandwiching them. .
In the present embodiment, the lower electrode 13b is transparent to the writing light 11, and the upper electrode 13a is transparent to the outgoing light.

  The photoconductive layer 15 a is a layer that generates and conducts electrons and holes, and moves carriers only in the region irradiated with the write light 11. Therefore, carriers are generated only in the region irradiated with the writing light 11 and conductivity is generated. As a result, the EC layer 17 is provided with or accepts electrons only in the region corresponding thereto.

As shown in FIG. 4, the photoconductive layer 15a includes a charge generation layer (CGM (carrier generation material) layer) that generates carriers and a charge transport layer (ETM (electron transfer layer) that moves the generated carriers. Material) layer) may be laminated. In this case, the charge transport layer acts to move carriers efficiently.
Further, the photoconductive layer 15a may be formed by stacking an HTM (Hole Transfer Material) layer in place of the charge transport layer in the configuration shown in FIG.

Various configurations of the EC display body 7a (or 7b, 7c) can be considered.
For example, as in the present embodiment shown in FIG. 5A, the electrode 13b / photoconductive layer 15a / EC layer 17 / electrolyte layer 19 / electrode 13a are stacked in this order from the lower layer, or FIG. 5B. As shown, the electrode 13b / EC layer 17 / electrolyte layer 19 / photoconductive layer 15a / electrode 13a may be stacked in this order from the lower layer.

The EC layer 17 may be provided in a plurality of layers.
For example, as shown in FIG. 6A, the electrode 13b / the photoconductive layer 15a / the first EC layer 17a / the electrolyte layer 19 / the second EC layer 17b / the electrode 13a are stacked in this order from the lower layer, or FIG. As shown in b), the electrodes 13b / first EC layer 17a / electrolyte layer 19 / second EC layer 17b / photoconductive layer 15a / electrode 13a may be stacked in this order from the bottom layer.
It is preferable that one of these EC layers 17a and 17b (for example, the first EC layer 17a) is an oxidation coloring EC, and the other (for example, the second EC layer 17b) is a reduction coloring EC.

  As the structure of the EC layer 17 and the electrolyte layer 19, as shown in FIG. 7A, the EC layer 17 and the electrolyte layer 19 are laminated, or as shown in FIG. Any one having an EC layer in which the EC material is dissolved in the electrolyte layer 19 and also serves as the electrolyte layer may be used. The EC layer here also includes a semiconductor nanoporous layer containing an EC dye, as described above. In addition, the EC layer in the present invention includes both an EC layer and an electrolyte EC layer provided separately from the electrolyte layer unless otherwise specified.

Next, an example of writing display using writing light of three wavelengths of the optical writing display element will be described.
FIG. 8 shows the configuration of an optical writing display element used to explain this action. As shown in FIG. 8, the optical writing display element 23 according to this example has an electrode 27 / first EC display layer 29a / electrode 27 / second EC display layer 29b / electrode 27 / third EC display layer 29c / electrode on a substrate 25. 27 are sequentially stacked. Here, the EC display layer refers to a laminate composed of layers included between the electrodes, and includes, for example, an EC layer, a photoconductive layer, and, if necessary, an electrolyte layer.

  The first EC display layer 29a is formed by laminating a first photoconductive layer 31a and a first EC layer 33a. The second EC display layer 29b is formed by laminating a second photoconductive layer 31b and a second EC layer 33b. The third EC display layer 29c is formed by laminating a third photoconductive layer 31c and a third EC layer 33c. Here, the first EC layer 33a is transparent-C colored. The second EC layer 33b is transparent-M colored. The third EC layer 33c is transparent-Y-colored. Each photoconductor, each electrolyte, and each electrode are transparent to visible light, and each EC layer and each electrode are transparent to writing light. The EC layer here is preferably an electrolyte EC layer.

The spectral sensitivity of each photoconductor is, for example, as shown in FIG. 9, in which the first photoconductive layer 31a is in the ultraviolet region λ ₁ , the second photoconductive layer 31b is in the ultraviolet region λ ₂ , and the third photoconductive layer 31c is in the ultraviolet region. Corresponds to the region λ ₃ .

In the optical writing display element 23 configured as described above, at the time of writing, as shown in FIG. 10A, each of the EC display layers is subjected to three types of writing light having wavelengths of λ ₁ , λ ₂ , and λ _3. An image is written to 29a, 29b, and 29c.

The writing light of λ ₃ is absorbed by the third photoconductive layer 31c and generates a photo carrier according to the light intensity. At this time, when a voltage causing color reaction is applied to the power source V ₃ , the _third EC layer 33 c is colored Y (yellow) corresponding to the light intensity.
The writing light of λ ₂ is absorbed by the second photoconductive layer 31b and generates a photo carrier according to the light intensity. At this time, when a voltage causing color reaction is applied to the power source V2, the _second EC layer 33b is colored M (magenta) corresponding to the light intensity.
The writing light of λ ₁ is absorbed by the first photoconductive layer 31a and generates a photo carrier according to the light intensity. At this time, when a voltage for color reaction is applied to the power source V ₁ , the first EC layer 33a is colored C (cyan) corresponding to the light intensity.

  At the time of erasing, write light corresponding to each EC display layer is irradiated to a portion to be erased, and a voltage that is decolored (transparent) is applied to a power source connected to the layer. When a voltage that causes an oxidation (reduction) reaction at the time of coloring is applied, a voltage that causes a reduction (oxidation) reaction at the time of decoloration is applied.

Next, for spatial movement of the writing light, that is, writing to another space (position), as shown in FIG. 10B, the writing light is moved in parallel with the substrate 25, and FIG. Write in the same way as The previously written portion is not irradiated with write light, so that the photoconductive layer is not a conductor, and no redox reaction occurs in each EC layer, and the previously written coloring state is maintained (memory).
There are various writing / erasing sequences. For example, the entire surface of the device may be erased initially, and then writing may be performed in an arbitrary space (position). Further, erasing may be performed for an arbitrary space (position), and then writing may be performed.

  Further, in the writing display example using the writing light of the three wavelengths, the method of controlling the coloring density corresponding to the light intensity is shown as the image forming means, but the coloring is performed according to the time of irradiation with the light having a constant intensity. The concentration may be controlled. Further, the coloring density may be controlled by the power supply voltage. Further, the color density may be controlled by a combination thereof.

  Furthermore, the coloring wavelength, the writing wavelength, and the number of EC display layers may be arbitrary in addition to this writing display example. The configuration of the EC display layer is not limited to this writing display example. For example, from the incident direction, the order of EC layer / photoconductive layer or the order of photoconductive layer / EC layer may be used. In this writing display example, an example of transmissive display is shown, but a reflective layer may be provided on one of the elements to provide a reflective display. Further, the irradiation direction of the writing light may be arbitrary. The optical writing display element may be provided with an optical filter in the element optical path as appropriate.

<Layer containing optical brightener>
In general, optical brighteners contain compounds having the property of absorbing light of a wavelength of about 320 to about 410 nm and emitting light of a wavelength of about 410 to about 500 nm. In addition to the original yellow reflected light, the fabric dyed with these fluorescent whitening agents is added with blue light having a wavelength of about 410 to about 500 nm, which is newly emitted by the fluorescent whitening agent, so that the reflected light is white. And the energy of visible light is increased by the amount due to the fluorescence effect, resulting in whitening.
In the image display device of the present invention, since light in the visible light region is transmitted and displayed, it is preferable that the fluorescent brightener does not absorb light in the visible light region (wavelength 410 nm to 800 nm) used for display. . That is, using a fluorescent whitening agent that absorbs light having a wavelength of 410 nm or less and emits light having a wavelength longer than 410 nm, with 410 nm being the shortest wavelength in the visible light region as a boundary. It is extremely efficient.

The layer containing the fluorescent brightening agent used in the present invention contains a transparent resin component and a fluorescent brightening agent, and absorbs and cuts 90% or more of light having a wavelength of 200 nm or more and 410 nm or less.
Light absorption is measured by visible and ultraviolet absorption spectroscopy.

  Examples of the transparent resin component of the layer containing the optical brightener include acrylic resin, urethane resin, aminoalkyd resin, epoxy resin, silica resin, and fluororesin. These resins can be arbitrarily mixed with a main agent, a curing agent, a diluent, a leveling agent, a repellant and the like.

  For example, when acrylic urethane resin or silicon acrylic resin is selected as the transparent resin component, polyisocyanate is used as the curing agent, hydrocarbon solvents such as toluene and xylene are used as the diluent, isobutyl acetate, butyl acetate, amyl acetate, etc. Alcohol solvents such as ester solvents, isopropyl alcohol, and butyl alcohol can be used.

  Specific examples of the transparent resin component include polymethyl methacrylate, polymethyl methacrylate styrene copolymer, polyvinyl chloride, and polyvinyl acetate. Here, the acrylic urethane resin refers to an acrylic urethane resin obtained by reacting a methacrylic ester (typically methyl), a hydroxyethyl methacrylate copolymer and a polyisocyanate. The polyisocyanate in this case includes tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, tolidine diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and the like.

  Further, in addition to these components, a leveling agent such as an acrylic resin or a silicone resin, an anti-fogging agent such as a silicone or acrylic resin, and the like can be blended as necessary.

  The optical brightener used in the present invention can be selected from commercially available compounds or compounds represented by the following general formula (1) based on light resistance and the like.

In general formula (1), R ¹ and R ⁴ each independently represent a hydrogen atom, an alkyl group or an alkoxy group, and R ² and R ³ each represent an alkyl group. A represents a substituted aryl group or a substituted ethenyl group. )

R ¹ , R ² , R ³ , R ⁴ and A in the general formula (1) of the present invention will be described in detail below.

R ¹ and R ⁴ each independently represents a hydrogen atom, an alkyl group or an alkoxy group, and specifically represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms.

More specifically, R ¹ and R ⁴ are each independently a hydrogen atom, methyl, ethyl, n-propyl, n-butyl, n-octyl, isopropyl, isobutyl, 2-ethylhexyl, t-butyl, t-amyl, Alkyl groups such as t-octyl, cyclopentyl or cyclohexyl, or alkoxy groups such as methoxy, ethoxy, n-propoxy, n-butoxy, n-octyloxy, isopropoxy, isobutoxy, 2-ethylhexyloxy, t-butoxy or cyclohexyloxy It is.
R ¹ and R ⁴ are preferably a hydrogen atom or an alkyl group, and particularly preferably a hydrogen atom.

R ² and R ³ represent an alkyl group, preferably an alkyl group having 1 to 16 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms.
More specifically, methyl, ethyl, n-propyl, n-butyl, n-octyl, n-hexadecanyl (cetyl), isopropyl, isobutyl, 2-ethylhexyl, t-butyl, t-amyl, t-octyl, cyclopentyl or cyclohexyl Represents an alkyl group such as

Preferably, R ² is a methyl group or a secondary or tertiary alkyl group having 1 to 10 carbon atoms, more preferably a methyl, isopropyl, t-butyl or cyclohexyl group, still more preferably t. -A butyl or cyclohexyl group.
R ³ is preferably a methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl or 2-ethylhexyl group, more preferably methyl, n-butyl, n-octyl or 2- An ethylhexyl group.

A represents a substituted aryl group or a substituted ethenyl group, more preferably a substituted aryl group having 6 to 40 carbon atoms or a substituted ethenyl group having 8 to 40 carbon atoms, and more preferably a substituted aryl group having 6 to 12 carbon atoms. Alternatively, it represents a substituted ethenyl group having 8 to 20 carbon atoms.
Preferred are substituted aryl or ethenyl groups shown below.

In the formula, R ³¹ and R ³⁴ have the same meanings as R ¹ and R ⁴ . R ³² has the same meaning as R ² described above. R ³³ has the same meaning as R ³ .
m represents an integer of 1 to 5, and preferably represents an integer of 1 to 3.

X and Y each independently represents alkyl, aryl, alkoxy, alkylamino, arylamino, amino or hydroxyl group.
Examples of the alkyl group represented by X and Y include methyl, ethyl, isopropyl, t-butyl, and cyclohexyl.
Examples of the aryl group represented by X and Y include phenyl, tolyl, and naphthyl.
Examples of the alkoxy group represented by X and Y include methoxy, ethoxy and isopropoxy.
Examples of the alkylamino group represented by X and Y include aminomethyl, ethylamino, octylamino, dimethylamino, and N-methyl-N-ethylamino. Examples of the arylamino group represented by X and Y include anilino, 4-tolylamino and N-methylanilino.
These groups represented by X and Y may further have a substituent, and examples of the substituent include the substituent group V.
X and Y are preferably an aryl group, an alkoxy group or an anilino group.

  The compound represented by the general formula (1) is preferably a compound represented by the following general formula (5). )

In general formula (5), R ²⁵ and R ²⁷ are groups having the same meaning as R ^2, and R ²⁶ and R ²⁸ are groups having the same meaning as R ³ . n is 1 or 2.
These compounds can be synthesized by the method described in JP-A-11-29556.

  Specific examples of the fluorescent brightening agent used in the present invention are listed below, but the present invention is not limited to these.

  The above is an example of an organic substance, but is not limited thereto, and may be an inorganic substance. These fluorescent brightening agents can be used alone or in combination of two or more as required. The amount of addition varies depending on the thickness of the molded product, the nature of the optical brightener, the presence or absence of UV absorbers, the nature, and the amount added, but those skilled in the art should carry out some tests. Can be easily determined. Generally, 0.1 to 10% by mass is sufficient for a coating film having a thickness of 0.1 mm. It can be considered that the blending amount and the thickness of the added material are almost inversely proportional. For example, by adding 5% by mass of the compound of formula (1), 3% by mass of the compound of formula (2), and 2.1% by mass of the compound of formula (13) to the 0.1 mm thick coating film, The light of 200 nm or more and 410 nm or less can be effectively cut substantially.

  As described above, in the present invention, the object can be achieved by blending the optical brightener in the transparent resin paint, but when there is anxiety about the light resistance of the optical brightener, When the short wavelength region cannot be cut sufficiently, it is desirable to use an ultraviolet absorber together. In general, an ultraviolet absorber is a compound having a property of absorbing ultraviolet rays and converting them into heat. They are roughly classified into benzotriazole, benzophenone, salicylic acid, and cyanoacrylate.

  The effective absorption wavelength of the benzotriazole system is about 270 to 380 nm, and representative examples include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole and 2- (2′-hydroxy-5′-t-butylphenyl). ) Benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole, 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl)- 5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-) t-Amylphenyl) benzotriazole, 2- (2′-hydroxy-4′-octoxyphenyl) benzotriazole and the like.

  The effective absorption wavelength of the benzophenone series is about 270 to 380 nm, and representative examples include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone and 2-hydroxy-4-dodecyl. Examples thereof include oxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone.

  The salicylic acid-based effective absorption wavelength is about 290 to 330 nm, and typical examples include phenyl salicylate, pt-butylphenyl salicylate, p-octylphenyl salicylate, and the like.

  The effective absorption wavelength of cyanoacrylate is about 270 to 350 nm, and typical examples include 2-ethylhexyl-2-cyano-3, 3-diphenyl acrylate, ethyl-2-cyano-3, 3-diphenyl acrylate, and the like. it can.

  In addition, it is preferable that these ultraviolet absorbers do not absorb light in the visible light region (wavelength 410 nm to 800 nm) used for display.

  These ultraviolet absorbers can be used alone or in combination of two or more. A suitable addition amount varies depending on the thickness of the coating film, the nature of the optical brightener, and the like, and thus cannot be uniquely determined. However, those skilled in the art can easily determine the amount by performing some tests. Generally, 1 to 30% by mass is sufficient for a coating film having a thickness of 0.1 mm.

  The layer containing the fluorescent brightener in the present invention contains a transparent resin component and a fluorescent brightener, and further uses an ultraviolet absorber as appropriate. The content of these compositions is preferably 0.1 to 20% by mass of a fluorescent brightening agent and 0 to 20% by mass of an ultraviolet absorber, based on the resin (100% by mass).

The thickness of the layer containing the optical brightener is preferably 2 to 1000 μm, more preferably 5 to 200 μm.
The method of applying these transparent resin components is arbitrary, but there are a spray method, a dipping method, a roller coating method, a flow coater method, a flow coating method and the like. Although drying after application varies depending on the transparent resin component, it is desirable to carry out at room temperature to 120 ° C. for about 10 to 90 minutes.

When the layer containing the fluorescent brightening agent is provided on the display surface side relative to the EC layer, the EC dye can be prevented from being decomposed and the durability of the display element can be improved. .
The layer containing the fluorescent brightening agent is preferably provided on the side of the support that is not on the display layer side. If it is provided on the display layer side, the execution voltage applied to the electrolyte layer is lowered, and the display performance is lowered.

  The liquid crystal element of the present invention can be suitably used as various types of electro-optical devices such as display elements such as computers, watches, and calculators, electro-optical shutters, electro-optical apertures, optical communication optical path switching switches, and optical modulators.

<Functional layer>
In the present invention, various functional layers may be further provided.
Examples of functional layers include optical functional layers such as antireflection layers, polarizing layers, color filter layers, white reflective layers, light extraction efficiency improving layers, mechanical functional layers such as hard coat layers and stress relaxation layers, and antistatic properties. Examples thereof include an electrical functional layer such as a layer / conductive layer, an antifogging layer, an antifouling layer, and a printing layer. In particular, the antistatic layer is excellent in that it stably imparts a high barrier ability. Details are shown below.

(Undercoat layer / back layer)
For example, in order to achieve adhesion between the substrate and the functional layer, after surface activation treatment, the functional layer is applied directly on the film to obtain adhesion, and after surface treatment or without surface treatment And a method of providing an undercoat layer (adhesive layer) and applying a functional layer thereon.
Various contrivances have also been made for the constitution of the undercoat layer, and a layer that is often adjacent to the support (hereinafter abbreviated as the undercoat first layer) is provided as the first layer, and a functional layer is provided as the second layer thereon. There is a so-called multi-layer method in which an undercoat second layer that adheres well is applied.

In the single layer method, good adhesion is often achieved by expanding the substrate and interfacial mixing with the undercoat layer material. Examples of the undercoat polymer preferably used in the present invention include water-soluble polymers, cellulose acylates, latex polymers, and water-soluble polyesters. Examples of water-soluble polymers include gelatin, gelatin derivatives, casein, agar, sodium alginate, starch, polyvinyl alcohol, polyacrylic acid copolymers, and maleic anhydride copolymers. Cellulose acylates include carboxymethyl cellulose and hydroxyethyl cellulose. Etc. Examples of the latex polymer include a vinyl chloride-containing copolymer, a vinylidene chloride-containing copolymer, an acrylate ester-containing copolymer, a vinyl acetate-containing copolymer, and a butadiene-containing copolymer.
In the first subbing layer in the multi-layer method, for example, a copolymer starting from a monomer selected from vinyl chloride, vinylidene chloride, butadiene, methacrylic acid, acrylic acid, itaconic acid, maleic anhydride and the like is used. As oligomers or polymers such as polyethyleneimine, epoxy resin, grafted gelatin, nitrocellulose and the like (for details, see EH Immergut, “Polymer Handbook” IV187-231, Interscience Pub. New York 1966, etc.) .

The undercoat layer optionally applied to the substrate used in the present invention may contain inorganic or organic fine particles as a matting agent so as not to substantially impair the transparency of the functional layer. As the inorganic fine particle matting agent, silicon dioxide (SiO ₂ ), titanium dioxide (TiO ₂ ), calcium carbonate, magnesium carbonate and the like can be preferably used. Examples of the organic fine-particle matting agent include polymethyl methacrylate, cellulose acetate propionate, polystyrene, a treatment solution-soluble one described in US Pat. No. 4,142,894, US Pat. Polymers described in US Pat. No. 4,396,706 can be used.

These fine particle matting agents preferably have an average particle diameter of 0.01 to 10 μm, more preferably 0.05 to 5 μm.
Moreover, the content is preferably 0.5 to 600 mg / m ² , more preferably 1 to 400 mg / m ² .

  The undercoating liquid is generally a well-known coating method, such as a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, It can be applied by a gravure coating method, a slide coating method, or an extrusion coating method using a hopper described in US Pat. No. 2,681,294.

  The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

<Example 1>
The display element shown in FIG. 11 was produced by the following operation.

(1) Production of plastic substrate with electrodes On one surface of transparent heat-resistant polyimide film (plastic substrate) 101 (I, S, manufactured by TA Corporation, thickness 400 μm), ITO was prepared with a thickness of 0.05 μm by DC sputtering. Then, the transparent electrode layer 102 was produced on the plastic substrate 101.

(2) Preparation of porous semiconductor fine particle layer containing EC dye [Preparation of semiconductor fine particles]
1) Particles C.I. J. et al. Barbe et al. Am. Ceramic Soc. Anatase-type titanium dioxide having a titanium dioxide concentration of 11% by mass using titanium tetraisopropoxide as the titanium raw material and setting the temperature of the polymerization reaction in the autoclave to 230 ° C. A dispersion of was synthesized. The primary particle size of the obtained titanium dioxide particles was 10 to 30 nm. The obtained dispersion was applied to an ultracentrifuge to separate the particles, and the agglomerates were dried, and then pulverized on an agate mortar to obtain a white powder.

2) Preparation of porous semiconductor fine particle layer The semiconductor fine particle of 1) above is added to a mixed solvent consisting of water and acetonitrile in a volume ratio of 4: 1 at a concentration of 32 g per 100 ml of solvent, and a rotating / revolving mixing conditioner is prepared. Used to uniformly disperse and mix. As a result, the obtained white dispersion became a paste having a high viscosity of 500 to 1500 P (= 50 to 150 N · s / m ² ) and was found to have liquid properties suitable for use as it is.
The high-viscosity paste-like coating solution is applied to the plastic substrate 101 having the ITO transparent electrode layer 102 with a uniform liquid thickness of 40 to 70 μm using an applicator, and the coating layer is dried at room temperature for about 1 hour. I let you.
Furthermore, after the coating layer was dried at 120 ° C. for 30 minutes, it was exposed to UV light from a 100 W mercury lamp ultraviolet light source for 30 minutes to perform post-treatment. Thus, the porous semiconductor fine particle layer 103 was produced. The film thickness of the porous semiconductor fine particle layer 103 was 30 μm.

[Adsorption of EC dye]
Next, in 2) above, 0.02M 2- {2- [4- (dimethylamino) phenyl] ethenyl} -3,3-dimethyl-5-phosphonoindolino [2,1-b] is used as the EC dye. ] Oxazoline and 0.02M 2- {2- [4- (dimethylamino) phenyl] -1,3-butadienyl} -3,3-dimethyl-5-carboxyindolino [2,1-b] oxazoline Dye in an acetonitrile solution containing 0.02M 2- {2- [4- (methoxy) phenyl] ethenyl} -3,3-dimethyl-5-phosphonoindolino [2,1-b] oxazoline Adsorption treatment was performed.

  As described above, the part 1 having the transparent electrode layer 102 and the porous semiconductor fine particle layer 103 on one surface of the plastic substrate 101 was produced by the operations of (1) and (2).

(3) Production of plastic substrate with back layer and electrode (part 2) [Production of plastic substrate with electrode]
On one surface of a transparent heat-resistant polyimide film (plastic substrate) 111 (made by I, S, Tei, thickness 400 μm), ITO is prepared with a thickness of 0.05 μm by DC sputtering, and the transparent electrode layer 112 is formed on the plastic substrate. 111.

After both surfaces of the plastic substrate 111 are subjected to corona discharge treatment, UV irradiation treatment, and glow discharge treatment, gelatin 0.1 g / m ² and sodium α-sulfodi-2-ethylhexyl succinate 0.01 g / m on one surface ² , salicylic acid 0.04 g / m ² , p-chlorophenol 0.2 g / m ² , (CH ₂ ═CHSO ₂ CH ₂ CH ₂ NHCO) ₂ CH ₂ 0.012 g / m ² , polyamide-epichlorohydrin heavy A condensate 0.02 g / m ² undercoat solution was applied (10 mL / m ² , using a bar coater) to provide an undercoat layer 113.
Thereafter, drying was performed at 115 ° C. for 6 minutes. The rollers and the conveying device in the drying zone were all set to 115 ° C. The thickness of the obtained undercoat layer 113 was 0.5 μm.

[Coating of back layer (antistatic layer, etc.)]
On the support on the side provided with the undercoat layer, an antistatic layer having the following composition and a sliding layer were coated as a back layer.

(Coating of antistatic layer)
A dispersion of fine particle powder (secondary agglomerated particle diameter of about 0.08 μm) of a tin oxide-antimony oxide composite having an average particle diameter of 0.005 μm with a specific resistance of 5 Ω · cm is 0.2 g / m ² and gelatin is 0.05 g / m ² , (CH ₂ = CHSO ₂ CH ₂ CH ₂ NHCO) ₂ CH ₂ 0.02 g / m ² , polyoxyethylene-p-nonylphenol (degree of polymerization 10) 0.005 g / m ² and resorcin 0.22 g / m ^{2 was} applied together to produce an antistatic layer 114. The film thickness of the antistatic layer 114 was 1.0 μm.

(Preparation of sliding layer)
Diacetylcellulose (25 mg / m ² ), C ₆ H ₁₃ CH (OH) C ₁₀ H ₂₀ COOC ₄₀ H ₈₁ (6 mg / m ² ) / C ₅₀ H ₁₀₁ O (CH ₂ CH ₂ O) ₁₆ H (9 mg / m ² ) The mixture was applied. This mixture was prepared by melting at 105 ° C. in xylene / propylene glycol monomethyl ether (1/1), pouring and dispersing in normal temperature propylene glycol monomethyl ether (10 times amount), and then dispersing in acetone. The product (average particle size 0.01 μm) was added. Silicon dioxide particles (0.3 μm) were added as a matting agent so as to be 15 mg / m ² . Drying was performed at 115 ° C. for 6 minutes (all rollers and conveyors in the drying zone were 115 ° C.). The sliding layer has a dynamic friction coefficient of 0.06 (5 mmφ stainless hard ball, load 100 g, speed 6 cm / min), static friction coefficient 0.07 (clip method), and the dynamic friction coefficient of the display surface and the sliding layer is 0.12. It was a characteristic. The thickness of the sliding layer 115 was 1.0 μm.

(Preparation of hard coat layer)
Further, a hard coat layer 116 was placed on the sliding layer 115 by the method described in JP-A-6-123806. The film thickness of the hard coat layer 116 was 1.0 μm.

[Preparation of white light reflection layer]
On the transparent electrode layer 112, a white light reflecting layer 117 was formed by applying a coating liquid prepared by dispersing a white pigment made of titanium oxide whose surface activity was eliminated by surface treatment together with 5% by mass of carboxycellulose. .

[Preparation of adhesive layer]
Further, Dic Dry WS-321A / LD-55 (Dainippon Ink Chemical Co., Ltd.), which is a completely water-based dry laminate adhesive, is applied on the white light reflecting layer 117, and then dried to be a 4 μm thick adhesive layer 118. Was made.

  Through the above operation, the transparent electrode layer 112, the white light reflecting layer 117, and the adhesive layer 118 are provided on one surface of the plastic substrate 111, and the undercoat layer 113, the antistatic layer 114, the sliding layer 115 are provided on the other surface. Part 2 having a hard coat layer 116 was produced.

(4) Preparation of a layer containing a fluorescent brightening agent and ultraviolet absorption 5.0% by mass of the compound of the formula (1) of the above specific example, 2- (2′-hydroxy-) with respect to Acrytech (trade name, manufactured by Dainippon Ink) 5'-t-butylphenyl) benzotriazole (1.1% by mass) was added to 15 g, and toluene: methyl ethyl ketone = 1: 1 (85 g) was added to dissolve the solid content to obtain a fluorescent brightener and an ultraviolet absorbing composition. .
This ultraviolet absorbing composition was applied on the plastic substrate 101 of part 1 and the hard coat layer 116 of part 2 to a thickness of 100 μm after drying, and layers 120 and 121 containing a fluorescent brightener and an ultraviolet absorber were produced. .
In addition, it was confirmed that the light absorptivity of 410 nm or less of the layers 120 and 121 containing the fluorescent brightening agent and the ultraviolet absorber is 90% or more.

(5) Production of EC element The EC element was assembled by bringing the parts 1 and 2 into contact with each other. The distance between the two electrodes was 0.5 mm. A 0.2M tetrabutylammonium perchlorate propylene carbonate solution was used as the electrolyte solution. Specifically, a partition wall (polystyrene) having a thickness of 0.5 mm is formed at the ends of parts 1 and 2, and after injecting an electrolyte solution, parts 1 and 2 are sealed with an epoxy-based adhesive. Layer 119 was made.
In addition, the magnitude | size of the produced pair electrode was 5 mm x 5 mm. A pair of electrodes in the obtained EC element was connected with lead wires (part 1 side electrode on the anode and part 2 side electrode on the cathode) to produce a display device.

<Evaluation of display performance>
When a voltage of 3 V was applied to this display device at room temperature, three kinds of styryl derivatives were oxidized at the anode and changed from colorless to black. As an element, it changed from white to black. The response speed until reaching the reached transmittance was 80 msec. Even after the voltage application was stopped, the colored state continued for 600 seconds or more.
Further, when a voltage of 3 V was applied with the anode and cathode reversed, the color changed from black to colorless. Next, after the EC element was irradiated with light from a high-pressure mercury lamp for 120 hours, the color density at the time of color development and the transparency at the time of color erasure hardly changed even when the color development / decoloration was repeated 10,000 times.

<Comparative Example 1>
In the same manner as in Example 1, except that an equimolar amount of ISCLALL manufactured by Sumitomo 3M was used instead of the compound of formula (1) in the specific example in the layer containing the fluorescent brightener and the ultraviolet absorber. A display element of Comparative Example 1 was obtained.
The composition containing ISCLARL (trade name) manufactured by Sumitomo 3M Limited was confirmed to have an absorption rate of light of 410 nm of 85%.

  About the display element of this comparative example 1, when irradiated with the light of a high pressure mercury lamp for 120 hours like Example 1, it is observed visually that the color intensity at the time of color development falls, and also the transparency at the time of decoloring It was confirmed that it also decreased. That is, it was confirmed that the display element of Example 1 of the present invention had higher display performance at the time of repetition than the display element of Comparative Example 1.

<Example 2>
The display element shown in FIG. 12 was produced by the following operation.

(1) Production of plastic substrate with electrodes On one surface of transparent heat-resistant polyimide film (plastic substrate) 201 (I, S, manufactured by TA Corporation, thickness 400 μm), ITO is prepared with a thickness of 0.05 μm by DC sputtering. Then, the transparent electrode layer 202 was produced on the plastic substrate 201.

(2) Production of Porous Semiconductor Fine Particle Layer Containing EC Dye Using a dispersion of anatase-type titanium dioxide prepared in Example 1, using titanium oxide paste (Solaronix, Ti-Nanoxide HT), A porous semiconductor fine particle layer 203 containing an EC dye was prepared in the same manner except that it was prepared to have a dry film thickness of 10 μm, dried and then heat-treated in air at 350 ° C. for 1 hour.

(3) Preparation of electrolyte layer The electrolyte solution used the propylene carbonate solution of 0.2M tetrabutylammonium perchlorate.
A partition wall (made of polystyrene) having a thickness of 0.5 mm was formed at the end of the substrate on the porous semiconductor fine particle layer side, and an electrolyte solution was injected into the inside thereof to prepare an electrolyte layer 204.

  As described above, the part 3 having the transparent electrode layer 202, the porous semiconductor fine particle layer 203, and the electrolyte layer 204 on one surface of the plastic substrate 201 was produced by the operations of (1) to (3).

(4) Production of plastic substrate (part 4) with a photoconductive layer etc. [Production of transparent electrode layer and back layer]
Similar to the production of the part 2 of Example 1, except that the white light reflecting layer and the adhesive layer are not formed, the plastic substrate 211 has a transparent electrode layer 212 on one surface, and the other surface is undercoated. A layer 213, an antistatic layer 214, a sliding layer 215, and a hard coat layer 216 were produced.

[Preparation of photoconductive layer]
On the transparent electrode layer 212, benzimidazole perylene (BZP) was formed as a charge generation layer 217 by vapor deposition to a thickness of 0.08 μm.
Next, as the charge transport layer 218, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine (biphenyl-diamine-based material) 7 is used. By coating a solution of 2% by mass, polycarbonate bisphenol Z (poly (4,4′-cyclohexylidene diphenylene carbonate)) 10.8% by mass and monochlorobenzene 82% by mass by spin coating, a 3 μm thick film was formed. Formed.
Further, 0.08 μm of BZP was laminated to form a charge generation layer 219.

[Preparation of white light reflection layer]
A white light reflection layer coating solution was prepared by dispersing a white pigment made of titanium oxide whose surface activity was eliminated by surface treatment together with 5% by mass of carboxycellulose.
This white light reflective layer coating solution was applied onto the charge generation layer 219 to form a white light reflective layer 220.

[Preparation of adhesive layer]
On the white light reflection layer 220, Dic Dry WS-321A / LD-55 (Dainippon Ink and Chemicals), which is a completely water-based dry laminate adhesive, was applied and dried to prepare an adhesive layer 221 having a thickness of 4 μm.

  By the above operation, the transparent electrode layer 212, the charge generation layer 217, the charge transport layer 218, the photoconductive layer 222 in which the charge generation layer 219 is laminated, the white light reflection layer 220, and the adhesive layer 221 are formed on one surface of the plastic substrate 211. A part 4 having an undercoat layer 213, an antistatic layer 214, a sliding layer 215, and a hard coat layer 216 on the other surface was prepared.

[Production of EC element]
In the same manner as in Example 1, parts 222 and 223 containing fluorescent whitening agent and ultraviolet absorption are produced on parts 3 and 4 and parts 3 and 4 are brought into contact with each other to produce an EC device of the present invention. did.

<Image writing and erasing>
About this display apparatus, 10 mW / m < ² > exposure was performed in the state which short-circuited the conductive layer by the side of a counter electrode layer, and the conductive layer by the side of a semiconductor layer. In the light irradiation part, three kinds of styryl derivatives were oxidized at the anode, and changed from colorless to black. The density of the irradiated part was 2.8.
The response speed until reaching the reached transmittance was 80 msec. Even after the light irradiation was stopped, color development lasted for 600 seconds or more.
Next, when a voltage of 1.5 V was applied so that the semiconductor layer side became a cathode, all images were erased.
Further, even when the color development / decoloration was repeated 10,000 times, the color density at the time of color development and the transparency at the time of color erasure hardly changed.

<Comparative Example 2>
Comparative Example 1 was carried out in the same manner as in Example 2, except that an equimolar amount of ISCLARL manufactured by Sumitomo 3M Ltd. was used instead of the compound of the formula (1) in the specific example in the layer containing the fluorescent brightener and the ultraviolet absorber. The display element was obtained.
The composition containing ISCLARL (trade name) manufactured by Sumitomo 3M Limited was confirmed to have an absorption rate of light of 410 nm of 85%.

  With respect to the display element of Comparative Example 2, when coloring and decoloring were repeated 10,000 times in the same manner as in Example 2, it was visually observed that the color density at the time of coloring decreased, It was confirmed that the transparency was also lowered. That is, it was confirmed that the display element of Example 2 of the present invention had higher display performance at the time of repetition than the display element of Comparative Example 2.

It is a conceptual diagram showing the optical writing display apparatus of this invention. An example of the writing display element of this invention is shown. An example of the writing display body of this invention is shown. An example of the photoconductive layer of this invention is shown. (A) (b) shows the structural variation example of EC display body of this invention. (A) (b) shows the structural variation example of EC display body which provided multiple layers of EC layer of this invention. (A) (b) shows the example of a variation of a structure of EC layer and electrolyte layer of this invention. The schematic of the example of a writing display by the optical writing display element of this invention is shown. FIG. 9 shows the relationship between the spectral sensitivity and wavelength of each photoconductor in FIG. (A) (b) shows the schematic of the example of writing by the optical addressing display element of this invention. 1 is a schematic cross-sectional view of an optical writing display element in Example 1. FIG. FIG. 3 is a schematic cross-sectional view of an optical writing display element in Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical writing display apparatus 3 Writing display board 5 Writing apparatus 7 Writing display element 7a, 7b, 7c EC display body 9 Reflective film 11 Writing light 13a Front electrode 13b Rear electrode 15a Photoconductive layer 17 EC layer 19 Electrolyte layer 23 Optical writing display Element 25 Substrate 27 Electrode 29 EC display layer 31 Photoconductive layer 33 EC layer 101, 111, 201, 211 Plastic substrate 102, 112, 202, 212 Transparent electrode 103, 203 Porous semiconductor fine particle layer 117, 220 White light reflection layer 120 121, 222, 223 Layer 204 containing fluorescent brightener and UV absorber Electrolyte layer 217, 219 Charge generation layer 218 Charge transport layer 222 Photoconductive layer

Claims (11)

  On the support, it has an electrode layer, at least one layer containing an electrochromic dye, and at least one layer containing a fluorescent whitening agent that absorbs 90% or more of light of 200 nm to 410 nm. A characteristic image display device.   The image display device according to claim 1, wherein the layer containing the optical brightener further contains an ultraviolet absorber.   On a support, it has a first electrode layer, a layer containing the at least one electrochromic dye, a photoconductive layer, a layer containing the fluorescent brightening agent, and a second electrode layer, the first electrode layer and the 3. The image display device according to claim 1, wherein the electrochromic dye-containing layer and the photoconductive layer are provided between the electrode layers including the second electrode layer. 4.   At least one of the first electrode layer and the second electrode layer is a transparent electrode, a semiconductor nanoporous layer is provided between the electrode layers adjacent to one or both of the transparent electrodes, and the semiconductor nanoporous layer The image display device according to claim 3, wherein the image display device is a layer containing the at least one electrochromic dye.   The image display according to any one of claims 1 to 4, wherein the layer containing at least one electrochromic dye is a layer containing a plurality of electrochromic dyes that develop different colors. apparatus.   The image display device according to claim 3, wherein the photoconductive layer contains an organic photoconductor as a main component.   The image display element according to claim 1, wherein the electromic dye is an organic dye.   The image display device according to any one of claims 3 to 7, wherein the photoconductive layer is changed in conductivity by visible light.   The image display apparatus according to claim 1, wherein the fluorescent brightening agent is a benzoxazole derivative. The image display apparatus according to claim 9, wherein the benzoxazole derivative is represented by the following general formula (1).

[In general formula (1), R ¹ and R ⁴ each independently represents a hydrogen atom, an alkyl group or an alkoxy group, R ² and R ³ represent an alkyl group, and A represents a substituted aryl or ethenyl group. Represents. ]   Using the image display device according to any one of claims 1 to 10, light writing of 200 nm or more and 410 nm or less is absorbed by 90% or more, and optical writing is performed by light substantially of 410 nm or more and 700 nm or less. An image forming method.

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