JPH0580310A - Optical element - Google Patents

Abstract

(57) [Outline] The optical element of the present invention comprises a binder polymer, a polymerizable monomer, a liquid crystal having refractive index anisotropy, and a photopolymerization initiator between transparent conductive films to which voltage can be applied. In addition, it is characterized in that a photosensitive layer having a holographic interference fringe formed of a cured layer and an uncured layer is sandwiched. The optical element of the present invention can be used as a radiation transmission film or a reflection film by a voltage on / off operation, and the reflected light wavelength and the reflection angle can be controlled by the design of holographic interference fringes, so that the heat rays can be selectively emitted. And the like can be used as a film that controls reflected light or transmitted light, and is useful as a light control element. Further, the hologram display can be arbitrarily displayed by the voltage on / off operation, and it can be used as a display element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to visible light, near infrared rays,
The present invention relates to a light control element that selectively transmits and reflects infrared rays, heat rays, and the like, and is attached or sandwiched on a window glass or the like to appropriately maintain the temperature in the room, the inside of a vehicle, and the like, and an optical element that can arbitrarily display a hologram.

[0002]

2. Description of the Related Art Conventionally, as a light control element, one in which a thin film of metal or the like is vapor-deposited on glass is known, but it is not possible to reversibly control the degree of reflection and the presence or absence of reflection. As a display element using a hologram, a silver salt or a photosensitive material on which interference fringes are recorded is known, but the display cannot be arbitrarily changed.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides an optical element which can reversibly control the presence or absence of reflection and can control the degree of reflection of light of a specific wavelength, and which can be used as a dimming element or a display element. The challenge is to provide.

[0004]

The optical element of the present invention comprises:
Between the transparent conductive film to which voltage can be applied, a binder polymer,
It is characterized by sandwiching a photosensitive layer formed of a polymerizable monomer, a liquid crystal having a refractive index anisotropy, and a photopolymerization initiator, and having a holographic interference fringe formed of a cured layer and an uncured layer.

Further, it is characterized in that the optical element is a light control element or a hologram display element.

The optical element of the present invention will be described below.

FIG. 1 is a diagram for explaining an optical element of the present invention by its sectional view, in which 1 is an optical element and 2 is an optical element.
Is a photosensitive layer, 3 is a cured layer, 4 is an uncured layer, and 5 is a transparent conductive film.

As shown in FIG. 1, the optical element 1 of the present invention.
Has a photosensitive layer 2 sandwiched between two transparent conductive films 5, and holographic interference fringes are recorded on this photosensitive layer by using the two-beam method. The interference fringe layer is composed of a portion 3 (exposed portion) cured by interference and a portion 4 (unexposed portion) in which light energy is canceled by interference, and the unexposed portion contains liquid crystal.

To produce such an optical element, a plastic film is laminated on the surface of a photosensitive layer comprising a binder polymer, a polymerizable monomer, a liquid crystal having a refractive index anisotropy, and a photopolymerization initiator on the plastic film. After that, the laser beam is irradiated by the two-beam interference method to form interference fringes, the interference fringes are further formed, the plastic film is peeled off, and a transparent conductive film is formed on both surfaces of the plastic film by an evaporation method or the like to form an optical element. Can be produced.

Examples of the photosensitive material include a material system including a binder polymer, a polymerizable monomer, a liquid crystal having a refractive index anisotropy, a photopolymerization initiator and the like.

As the binder polymer, polymethacrylic acid ester or its partial hydrolyzate, polyvinyl acetate or its hydrolyzate, polystyrene, polyvinyl butyral, polychloroprene, polyvinyl chloride, chlorinated polyethylene, chlorinated polypropylene, poly -N-vinylcarbazole or a derivative thereof, poly-N-vinylpyrrolidone or a derivative thereof, a copolymer of styrene and maleic anhydride or a half ester thereof, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, acrylamide, acrylic A copolymer having a monomer selected from a group of copolymerizable monomers such as nitrile as a polymerization component is used.

Particularly preferred is poly-N-vinylcarbazole or a derivative thereof, for example, poly-N-vinylcarbazole, vinylcarbazole-styrene copolymer, vinylcarbazole-vinyl chloride copolymer, vinylcarbazole-methylmethacrylate. Copolymer, vinylcarbazole-vinylanthracene copolymer, vinylcarbazole-vinylpyridine copolymer, vinylcarbazole-acrylate copolymer, vinylcarbazole-
Ethyl acrylate copolymer, vinylcarbazole-acrylonitrile copolymer, vinylcarbazole-butylacrylate copolymer, vinylcarbazole-nitrovinylcarbazole copolymer, nitrated poly-N-vinylcarbazole, polyvinylaminocarbazole, vinylcarbazole-N -Methylaminovinylcarbazole copolymer, halogen-substituted poly-N-vinylcarbazole,
Examples thereof include vinylcarbazole-dibromovinylcarbazole copolymer, polyiodovinylcarbazole, polybenzylidenevinylcarbazole, and polypropenylcarbazole. When these poly-N-vinylcarbazoles are used as a binder polymer, it is possible to obtain a hologram having good moisture resistance. Also, poly-N-
Vinylpyrrolidone or a derivative thereof is also preferable, and examples thereof include copolymers of poly-N-vinylpyrrolidone and vinyl acetate, glycidyl methacrylate, alkyl (meth) acrylate, styrene and the like.

Next, the polymerizable monomer has a large curing shrinkage due to polymerization.

Such a polymerizable monomer is a photopolymerizable compound having an ethylenically unsaturated bond, and photopolymerizable or photocrosslinkable having at least one ethylenically unsaturated double bond in one molecule. Examples of the monomer and its copolymer are unsaturated carboxylic acid and its salt, ester of unsaturated carboxylic acid and aliphatic polyhydric alcohol compound, and unsaturated monomer, oligomer, prepolymer and mixture thereof. Examples thereof include amides of a carboxylic acid and an aliphatic polyvalent amine compound. Particularly, a bifunctional or higher-functional polyfunctional monomer has a large curing shrinkage and can be preferably used.

Specific examples of unsaturated carboxylic acid monomers include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, and their halogen-substituted unsaturated carboxylic acids such as chlorinated unsaturated carboxylic acids. Examples thereof include brominated unsaturated carboxylic acid and fluorinated unsaturated carboxylic acid. Examples of the salts of unsaturated carboxylic acids include sodium salts and potassium salts of the above-mentioned acids.

Specific examples of the monomer of the ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, and 1,3-butanediol diacrylate. Acrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4 -Cyclohexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol Lutriacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri ( Acryloyloxyethyl) isocyanurate, polyester acrylate oligomer and the like.

Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol. Dimethacrylate, hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis- [p- (3 -Methacryloxy-2- Mud propoxy) phenyl] dimethyl methane, bis - [p- (acryloxy ethoxy phenyl] dimethyl methane, 2,2-bis (4-methacryloyloxy) propane, methacrylate -2
-There is naphthyl, etc.

As the itaconic acid ester, ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,
4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate, sorbitol tetritaconate and the like can be mentioned.

As the crotonic acid ester, ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate,
Examples thereof include sorbitol tetracrotonate.

Examples of the isocrotonic acid ester include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate and sorbitol tetraisocrotonate.

Examples of the maleic acid ester include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate and sorbitol tetramaleate.

As the halogenated unsaturated carboxylic acid,
2,2,3,3-tetrafluoropropyl acrylate, 1H, 1H, 2H, 2H-heptadecafluorodecyl acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 1H, 1H, 2H, 2H-heptadeca Fluorodecyl methacrylate, methacrylic acid-
2,4,6-Tribromophenyl, dibromoneopentyl dimethacrylate (trade name: NK ester DBN, manufactured by Shin Nakamura Chemical Co., Ltd.), dibromopropyl acrylate (trade name: NK ester A-DBP, Shin Nakamura Chemical Co., Ltd.) Co., Ltd.), dipromopropyl methacrylate (trade name: NK ester DBP, Shin Nakamura Chemical Co., Ltd.),
Methacrylic acid chloride, methacrylic acid-2,4,6-
Trichlorophenyl, p-chlorostyrene, methyl-2
-Chloroacrylate, ethyl-2-chloroacrylate, n-butyl-2-chloroacrylate, tribromophenol acrylate, tetrabromophenol acrylate and the like can be mentioned.

Specific examples of the amide monomer of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound include methylenebisacrylamide, methylenebismethacrylamide, 1,6-hexamethylenebisacrylamide, 1,
6-hexamethylene bis methacrylamide, diethylene triamine tris acrylamide, xylylene bis acrylamide, xylylene bis methacrylamide, N-phenyl methacrylamide, diacetone acrylamide, etc. are mentioned.

As another example, Japanese Patent Publication No. 48-417.
No. 08 publication, a polyisocyanate compound having two or more isocyanate groups in one molecule and the following general formula CH ₂ ═C (R) COOCH ₂ CH (R ′) OH (wherein R and R ′ are hydrogen or And a vinyl urethane compound having two or more polymerizable vinyl groups in one molecule, to which a vinyl monomer having a hydroxyl group represented by the formula (1) is added.

Further, urethane acrylates described in JP-A-51-37193, JP-A-48-641
83, Japanese Patent Publication No. 49-43191, Japanese Patent Publication No. 5
Polyester acrylates, epoxy resins and (meth) as described in JP-A-2-30490, respectively.
Mention may be made of polyfunctional acrylates and methacrylates such as acrylic acid.

Furthermore, the magazine of Japan Adhesive Association Vol. 20, N
O7, those introduced as photocurable monomers and oligomers on pages 300 to 308 can also be used.

In addition, as the monomer containing phosphorus, mono (2-acryloyloxyethyl) acid phosphate (trade name: light ester PA, manufactured by Kyoeisha Oil and Fat Chemical Co., Ltd.), mono (2-methacryloylethyl) Acid phosphate (trade name: Light Ester PM, manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.), and epoxy acrylate type trade name: Lipoxy VR-60 (Showa Highpolymer Co., Ltd.), trade name: Lipoxy VR-90 (manufactured by Showa Highpolymer Co., Ltd.) and the like can be mentioned.

Trade name: NK ester M-230G
(Manufactured by Shin-Nakamura Chemical Co., Ltd.), trade name: NK ester 2
3G (manufactured by Shin-Nakamura Chemical Co., Ltd.) is also included.

Further, triacrylates having the following structural formula,

[0030]

[Chemical 1]

(Toagosei Chemical Industry Co., Ltd., trade name, Aronix M-315)

[0032]

[Chemical 2]

(Trade name, Aronix M-325, manufactured by Toagosei Kagaku Kogyo Co., Ltd.), and 2,2'-bis (4-
Acryloxy-diethoxyphenyl) propane (Shin-Nakamura Chemical Co., Ltd., trade name, NK ester A-BPE-4), tetramethylolmethane tetraacrylate (Shin-Nakamura Chemical)
(Trade name, NK ester A-TMMT), etc.

These polymerizable monomers are used in an amount of 0.1 to 3 parts by weight, preferably 0.3 to 1.5 parts by weight, based on 1 part by weight of the binder polymer.

Next, the photopolymerization initiator / sensitizer is 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 2-dimethylaminobenzoate, ethyl 2-dimethylaminobenzoate, 4-dimethyl. Ethyl aminobenzoate, butyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2,2-diethoxyacetophenone, benzyldimethylketal, benzyl-β-methoxyethylacetal. , 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, benzophenone, methyl o-benzoylbenzoate,
Michler's ketone, 4,4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, dibenzoyl (1,2-diphenylethanedione), benzoin (2-phenyl-2-hydroxy-acetophenone), benzoin methyl ether, benzoin ethyl ether , Benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, benzoin butyl ether (n and iso 50: 5
0 mixture), benzoin alkyl ether, 4'-isopropyl-2-hydroxy-2-methyl-propiophenone, 2-hydroxy-2-methyl-propiophenone, p-dimethylaminoacetophenone, pt-butyltrichloroacetophenone. , P-t-butyldichloroacetophenone, p-azidobenzaldehyde, p-azidoacetophenone, p-azidobenzoic acid, p-azidobenzalacetophenone, p-azidobenzalacetone, 4,4′-diazidochalcone, 1, 3-bis-
(4'-azidobenzal) -acetone, 2,6-bis-
(4'-azidobenzal) -cyclohexanone, 2,6
-Bis- (4'-azicytobenzal) -4-methylcyclohexanone, 4,4'-diazidostilbene-2,
2'-disulfonic acid, 1,3-bis- (4'-azidobenzal) -2-propanone-2'sulfonic acid, 1,3-
Bis- (4'-azidobenzal) -2-propanone-
2,2'-sodium disulfonate, 1,3-bis-
(4′-Azidocinnaylidene) -2-propanone, azidopyrene, 3-sulfonylazidobenzoic acid, 4-sulfonylazidobenzoic acid, 2,6-bis- (4′-azidobenzal) -cyclohexanone-2 ′, 2disulfone Acid (sodium salt), 2,6-bis- (4'-azidobenzal) -methyl-cyclohexanone 2,2'-disulfonic acid (sodium salt), 4-diazodiphenylamine sulfate, 4-diazo-4'-methoxy- Diphenylamine sulfate, 4-diazo-3-methoxy-diphenylamine, sodium salt of naphthoquinone (1,2) diazide (2) -4-sulfonic acid, sodium salt of naphthoquinone (1,2) diazide (2) -5-sulfonic acid Salt, naphthoquinone (1,2) diazide (2) -5-sulfonic acid ester (1), naphthoquinone (1, ) Diazide (2) -5-
Sulfonic acid ester, naphthoquinone (1,2) diazide (2) -5-sulfonic acid ester (3) -novolac resin ester, diazo resin (sulfate and zinc chloride double salt of diazodiphenylamine / paraformaldehyde condensate), tri Phenylpyrylium perchlorate, 4-methoxyphenyl-2,6-diphenylpyrylium perchlorate, 4-butoxyphenyl-2,6-diphenylpyrylium perchlorate, triphenylthiopyrylium perchlorate Salt, 4-methoxyphenyl-2,6-diphenylthiopyrylium perchlorate, thioxanthone, 2-methylthioxanthone (2-methyl-9H-thioxanthene-9-
On), chlorothioxanthone (2-chloro-9H-thioxanthene-9-one), 2-isopropylthioxanthone (2-isopropyl-9H-thioxanthene-9).
-On), dibenzosuberone, 2,5-bis- (4'-
Diethylaminobenzal) cyclopentanone, 1-acetylamino-4-nitronaphthalene, 5-nitroacenaphthene, 1-nitropyrene, α, α-dichloro-4-phenoxyacetophenone, 1-hydroxycyclohexylphenylketone, or trade name : Kayakyu MBP (manufactured by Nippon Kayaku Co., Ltd.), trade name: UVECRYL P36
(UCB) and the like, and these can be used alone or in combination.

Further, a coumarin compound represented by the following formula and an organic peroxide may be mentioned.

[0037]

[Chemical 3]

(In the formula, R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom, a chloro atom, a lower alkoxy group, a lower dialkylamino group, a lower dialkenylamino group or an alicyclic amino group. Has a total of 5 carbons and heteroatoms
~ 9 heterocyclic groups, or -COY group. Here, Y is a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a lower alkoxy group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted steryl group, or a substituted or unsubstituted 3'-coumarino group. Represent Z represents a hydrogen atom or a cyano group. In the formula, R ₁ , R ₂ and R ₃ are preferably hydrogen atom, chloro atom, lower alkoxy group such as methoxy, ethoxy and butoxy, lower dialkylamino such as dimethylamino, diethylamino and N-methyl-N-propylamino. Base, N
Examples thereof include alicyclic amino groups such as -morpholino and N-piperidino, and lower dialkenylamino groups such as dipropenylamino and di (α-methylpropenyl) amino groups.

As the heterocyclic group for X, 2-imidazole, 2-N-methylimidazole, 2-benzimidazole, 2- (4-phenyl) -imidazole, 2-oxazole, 2-benzoxazole, 2- (4- Phenyl) oxazole, 2-thiazole, 2-benzthiazole, 2- (4-phenyl) thiazole, 2- (5-
Phenyl) thiadiazole, 2- (5-tolyl) thiadiazole, 2- (5-biphenyl) thiadiazole, 2
-(5-phenyl) oxadiazole, 2- (5-p-
Methoxyphenyl) oxadiazole, 2- (5-p-
Examples thereof include residues such as chlorophenyl) oxadiazole.

As Y in the --COY group, methyl, ethyl, propyl, hexyl, β-cyanoethyl,
A substituted or unsubstituted C ₁ -C ₆ alkyl group such as ethoxycarbonylmethyl, butoxycarbonylmethyl, phenyl, p-cyanophenyl, p-methylphenyl, p-
A substituted or unsubstituted phenyl group such as methoxyphenyl and m-hydroxycarbonylphenyl, a steryl group such as steryl, p-methoxysteryl, p-cyanosteryl, and m-chlorsteryl, and a 3-coumarino group represented by the following formula:

[0041]

[Chemical 4]

(Wherein R ₁ , R ₂ , R ₃ and Z are the same as those in the above formula (1)) and the like.

Specific examples of the coumarin compound include 3-acetyl-7-dimethylaminocoumarin and 3-benzoyl-
7-dimethyl-aminocoumarin, 3-benzoyl-5,
7-dimethoxycoumarin, methyl, 7-diethylamino-3-coumarinoyl acetate, 3-cinnamoyl-7
-Diethylaminocoumarin, 3,3'-carbonylbis (7-diethylamino) coumarin, 3,3'-carbonylbis (5,7-dimethoxyamino) coumarin, 7-diethylamino-5,7'-dimethoxy-3,3 ' -Biscoumarin, 3- (2'-benzimidazoyl) -7-diethylaminocoumarin, 3- (2'-benzoxazoyl) -7-diethylaminocoumarin, 3- (5'-phenylthiadiazoyl-2 ') Examples include -7-diethylaminocoumarin, 3- (2'-benzthiazoyl) -7-diethylaminocoumarin, and 3,3'-carbonylbis (4-cyano-7-diethylamino) coumarin. ..

Preferred compounds of the organic peroxide used as a mixture with the coumarin compound are methyl ketone peroxide, cyclohexanone peroxide, acetylacetone peroxide, t-butyl peroxide, cumene hydroperoxide and diisopropylbenzene. Peroxide, t-butylcumyl peroxide, dicumyl peroxide, α, α′-bis (t-
Butyl cumyl peroxyisopropyl) benzene, t-
Butyl peroxy isopropyl carbonate, benzoyl peroxide, di (t-butyl peroxy) isophthalate, di (t-butyl peroxy) terephthalate, di (t-butyl peroxy) phthalate, t-butyl peroxybenzoate, 3, 3 ', 4,4'-tetra- (t-butylperoxycarbonyl) benzophenone, 2,5-dimethyl-2,5- (dibenzoylperoxy) hexane and the like are used.

Of these, particularly preferred are di (t-butylperoxy) isophthalate, di (t-butylperoxy) terephthalate, di (t-butylperoxy) phthalate, 3,3 ', 4. 4'-tetra-
(T-butylperoxycarbonyl) benzophenone is mentioned.

The proportion of the organic peroxide added to the coumarin compound is 1 part by weight to 1 part by weight of the coumarin compound.
It is 100 parts by weight, preferably 1 part by weight to 50 parts by weight.

These photopolymerization initiators are used in a proportion of 1 to 80 parts by weight, preferably 1 to 20 parts by weight, based on 100 parts by weight of the total amount of the binder polymer and the polymerizable monomer.

As the liquid crystal material, a general liquid crystal can be preferably used as long as it is a liquid crystal having a so-called refractive index anisotropy in which the refractive index changes when an electric field is applied. When selecting a liquid crystal material, a liquid crystal material having a refractive index equal to the refractive index of the cured layer in the photosensitive material at a predetermined electric field strength may be selected. The photosensitive material may be selected so as to have the same refractive index as that at a predetermined electric field strength of.

The liquid crystal may be nematic, cholesteric or smectic, for example, an azo compound, an azoxy compound, P-alkyl-substituted benzoic acid P-.
Cyanophenyl ester, P-cyanophenyl ester of P-alkyl-substituted benzoic acid, cholesteryl ester,
Cyano-substituted biphenyls, cyano-substituted biphenyls, substituted cyclohexanecarboxylic acid ester, substituted cyclohexanecarboxylic acid cyclohexyl ester, substituted cyclohexanecarboxylic acid aryl ester, thick base, P- (P-substituted cyclohexyl) substituted benzonitrile , P-[(P-decyloxybenzylidene) amino] cinnamic acid 2-methylbutyl ester, 2-phenyl-substituted-1,3-dioxane substituent, phenylpyrimidines, N, N '-[P-phenylenebis ( (Methylidine))]
Examples thereof include bis [P-alkylaniline].

The liquid crystal material is 1 part by weight to 5 parts by weight based on 100 parts by weight of the total amount of the binder polymer and the polymerizable monomer.
It is used in an amount of 00 parts by weight, preferably 20 parts by weight to 70 parts by weight.

In addition to the above composition, a thermal polymerization inhibitor, a plasticizer, etc. may be added. For example, benzene, chlorobenzene, tetrahydrofuran, 1,4-dioxane, 1,
It is dissolved in 2-dichloroethane, dichloromethane, chloroform or the like and coated on a support such as a transparent resin film. As a coating method, spinner coating, blade coating, roll coating or the like is applied to obtain a film thickness of 0.5 μm to 50 μm after drying.

The photosensitive layer thus obtained is sensitive to laser light having a bright line at, for example, 4579Å, 4880Å, 5145Å, 5287Å, etc.
1 to 1 for an Argon laser with a wavelength of 880Å
The energy of 500 mJ / cm ² gives diffraction efficiency in a practical range.

When forming a hologram, a coherent 2
A Lippmann hologram forming device that forms a volume phase hologram by irradiating the photosensitive layer with radiation of a bundle at a predetermined offset angle, and a Dennisuk that forms a volume phase hologram by the interference between the irradiation light and the light reflected by the photosensitive layer. Type hologram forming apparatus can be used, and as the radiation, laser light such as Ar ⁺ laser, He-Ne laser, and Kr laser, and radiation using a mercury lamp as a light source are preferable.

The distance between the interference fringes can be controlled by appropriately selecting the photosensitive material and the method of forming the interference fringes, the wavelength of the diffracted light can be appropriately set, and the reflection angle thereof can be appropriately set.

Examples of the transparent conductive film formed on both sides of the photosensitive layer include general conductive materials such as indium tin oxide, tin oxide and zinc oxide. Sputtering method, vapor deposition (electrode) method, dip coating method, etc. Is formed by.
Further, by using the transparent conductive film formed in a pattern, it is possible to reproduce a hologram image in a pattern.

[0056]

The photosensitive layer in the optical element of the present invention comprises a binder polymer, a polymerizable monomer, a liquid crystal having a refractive index anisotropy, and a photopolymerization initiator. When exposed, the polymerizable monomer is polymerized in the exposed area to cause curing shrinkage, resulting in a density difference, and the adjacent polymerizable monomer moves to the exposed area and is further polymerized. At the same time, the liquid crystal in the exposed area is expelled and moves to the unexposed area. Interference fringes composed of layers are formed.
Since the refractive index of the liquid crystal material changes depending on the electric field, the reflection intensity changes stepwise depending on the strength of the electric field.

For example, if the refractive index of the liquid crystal layer is different from that of the exposed portion when the voltage is off and the refractive index is the same when an electric field is applied, the liquid crystal layer becomes transparent when a voltage is applied and becomes a radiation transmissive film. Since the refractive index is different when the voltage is off, it can be used as a radiation reflecting film.

When a radiation reflecting film is used, the wavelength of reflected light and the angle of reflection can be controlled by designing the holographic interference fringe layer. Therefore, it is possible to selectively reflect heat rays and control the wavelength of transmitted light. Therefore, it is useful as a light control element. That is, it can be kept cool in the summer and warm in the winter by attaching or sandwiching it on the window glass of automobiles, buildings, greenhouses, etc.
The capacity and fuel efficiency of the air conditioner can be improved. Further, by connecting the transparent electrode in the optical element to the solar cell, the intensity of sunlight and the intensity of the electric field can be correlated, and the intensity of reflection can also be controlled. In addition, since the degree of reflection can be changed stepwise depending on the strength of the electric field, it is possible to form a film that reflects heat rays in summer and transmits heat rays in winter.

Further, when the optical element of the present invention is used as a hologram display element, it becomes transparent when a voltage is applied and the hologram is not observed, but the refractive index is made different when the voltage is off, so that the recorded hologram should be revealed. You can It is also possible to reproduce an arbitrary hologram image by forming a hologram interference fringe layer uniformly on the photosensitive layer, patterning the transparent conductive film, and controlling voltage application by signal information.

As described above, the refractive index of the liquid crystal layer is different from that of the exposed portion when the voltage is off, and the same refractive index is applied when the electric field is applied. On the contrary, the refractive index of the liquid crystal layer and the exposed portion is one when the voltage is off. However, it may be different when an electric field is applied, and in this case, the functions as a dimming element and a display element when the voltage is turned on and off can be reversed from those described above.

The present invention will be described below with reference to examples.

[0062]

Example 1

[0063]

[Table 1]

The photosensitive film having the composition shown in Table 1 was dried to a film thickness of 10 μm.
Coating on a PET film (Lumirror HP-7, 25 μm, manufactured by Toray Industries, Inc.) using an applicator so that the film is baked at 60 ° C. for 10 minutes to dry the film.
A PET film was laminated on the upper surface.

Next, 5 W of Ar ⁺ laser light (488
nm), and 0.5 mw / cm by two-beam interferometry
Irradiation at an intensity of ² for 60 seconds formed interference fringes. The exposed area had a refractive index of 1.51, and the unexposed area had a refractive index of 1.49.

Next, the surface of this film was evacuated to 10 ^-5 Torr or less, and then a mixed gas of argon and oxygen was introduced to make the degree of vacuum 5 × 10 ^-3 Torr by using a sputtering apparatus of 200 W. Apply ITO to 1000 power
A transparent conductive film was formed with a film thickness of Å.

Further, P on the side where the transparent conductive film is not formed
After peeling off the ET film, an ITO film was similarly formed on the peeled surface to form an optical element composed of a photosensitive layer sandwiched between transparent conductive films.

An electric field of 0.3 is applied between the transparent conductive films (electrodes).
When V was applied, the liquid crystal was slightly aligned, the refractive index was the same as that of the exposed portion, and it became transparent to 488 nm light. When the electric field strength was further increased, the liquid crystal was oriented and the difference in refractive index from the exposed portion was 0.04, so that light of 488 nm was reflected.
During this time, the reflected light became stronger as the intensity increased.

[0069]

Example 2 One of the transparent conductive films in the optical element formed in the same manner as in Example 1 was patterned by a sputtering method through a patterned chromium mask.

When a voltage of 0.3 V was applied between both electrodes, 488 nm light was reflected only in the portion where the transparent conductive film was present, and blue pattern reflected light was obtained.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an optical element of the present invention with a sectional view.

[Explanation of symbols]

1 is an optical element, 2 is a photosensitive layer, 3 is a cured layer, 4 is an uncured layer, and 5 is a transparent conductive film.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03H 1/02 8106-2K

Claims (4)

[Claims] 1. A hollow comprising a binder polymer, a polymerizable monomer, a liquid crystal having a refractive index anisotropy, and a photopolymerization initiator between transparent conductive films to which a voltage can be applied, and a cured layer and an uncured layer. An optical element characterized by sandwiching a photosensitive layer on which graphic interference fringes are formed. 2. The optical element according to claim 1, wherein the optical element is a dimming element. 3. The optical element according to claim 1, wherein the optical element is a hologram display element. 4. The optical element according to claim 3, wherein the transparent conductive film is provided in a pattern.