JPH09230776A - Formation of hologram - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to easily manufacture a hologram having high light transmittance and improved diffraction efficiency by recording the hologram on a dry process hologram recording layer, then irradiating the layer with the absorption wavelength light intrinsic to sensitizing dyestuff to cause the color fading of the sensitizing dyestuff. SOLUTION: After the hologram is recorded on the dry process hologram recording layer consisting of a matrix polymer, photopolymerizable compd., a photopolymn. initiator and the sensitizing dyestuff, the recording layer is irradiated with the absorption wavelength light intrinsic to the sensitizing dyestuff to cause the color fading of the sensitizing dyestuff. The fading of the sensitizing dyestuff having absorption in a wavelength region of, for example, 350 to 600nm as such color fading stage is successfully executed by exposing the dyestuff to fluorescent light and natural light of intensity of 500 lux for 20 to 60 hours, depending on the dyestuff quantity. The colored hologram recording layer is rapidly and easily faded in the color in such a manner, by which the transmittance is raised up to 93%. The sensitizing dyestuff may be irradiated with the light of the similarly corresponding wavelength region in order to cause the color fading of the sensitizing dyestuff having the absorption in the wavelength region of <=350nm or >=600nm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hologram forming method relating to post-processing after hologram recording in a color Lippmann hologram, which is a hologram optical element such as a holographic element which needs to selectively diffract light of a desired wavelength. The present invention relates to a hologram forming method useful as a color filter or a head-up display.

[0002]

2. Description of the Related Art Holograms are manufactured by recording interference fringes generated by interference between laser light from a light source and laser light from an object on a photosensitive resin. Photoresists, dichromated gelatin, silver halide, etc. are known as recording materials, but all have problems in resolution, cost, moisture resistance, etc., and good volume phase holograms have been obtained. Absent. Further, these methods also have a drawback that the work efficiency is poor because a developing step is indispensable after hologram recording.

On the other hand, the hologram recording method, which has been actively researched in recent years and utilizes the difference in refractive index caused by the movement of monomers, is a volume type phase hologram recording material which does not require a developing step and is excellent in productivity. Attention has been paid. This method is called a dry hologram recording material because it does not need to be immersed in a developing solution.

[0004]

Generally, a hologram recording material is composed of a matrix polymer, a photopolymerizable compound, a photopolymerization initiator and a sensitizing dye, and a photopolymerization initiator which is an initiator system and a sensitizer. As a combination with a dye, a sensitizing dye having a spectral sensitivity in the wavelength region of recording light is used, which makes it possible to form a highly sensitive starting system.

However, most of the sensitizing dyes have high sensitivity in the visible light region of 350 to 600 nm when the laser light is used as the recording light, and there is a problem that the transmittance decreases when reproducing hologram recording. Have. When performing development processing using a developing solution after hologram recording, the sensitizing dye is removed during the development processing, so such a problem does not occur. However, in the dry hologram recording layer, hologram recording is not performed. After that, the photopolymerization initiator such as an organic peroxide is decomposed from the viewpoint of stabilizing the recording, but the sensitizing dye still remains in the hologram, and the transmittance of the obtained hologram is low. However, there is a problem that the diffraction efficiency does not seem to be high. Such a problem is a particular problem in the transmission type volume phase hologram.

An object of the present invention is to provide a hologram forming method capable of easily and promptly producing a hologram having a high light transmittance and a high diffraction efficiency in a dry hologram recording layer.

[0007]

As a result of various studies to solve the above problems, the hologram forming method of the present invention comprises a matrix polymer, a photopolymerizable compound, a photopolymerization initiator and a sensitizing dye. After the hologram is recorded on the dry hologram recording layer, a step of irradiating the absorption wavelength light peculiar to the sensitizing dye to fade the sensitizing dye is performed.

Further, the hologram forming method of the present invention is characterized in that the hologram is a transmission type volume phase hologram.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The hologram recording light-sensitive material layer in the present invention is a photosensitive material for dry type volume phase hologram recording, and comprises a matrix polymer, a photopolymerizable compound, a photopolymerization initiator and a sensitizing dye. Consists of.

The photopolymerizable compound is a photopolymerizable or photocrosslinkable monomer or oligomer having at least one ethylenically unsaturated bond in one molecule as described below.
Prepolymers and mixtures thereof can be mentioned, for example, unsaturated carboxylic acids and salts thereof, esters of unsaturated carboxylic acids with aliphatic polyhydric alcohol compounds, unsaturated carboxylic acids with aliphatic polyhydric amine compounds. Examples include amide-bonded products.

Specific examples of the unsaturated carboxylic acid monomer 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. , Brominated unsaturated carboxylic acids, fluorinated unsaturated carboxylic acids and the like. 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 the aliphatic polyhydric alcohol compound and the 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, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, phenol ethoxylate monoacrylate, 2- (p-chlorophenoxy)
Ethyl acrylate, p-chlorophenyl acrylate, phenyl acrylate, 2-phenylethyl acrylate, (2-acryloxyethyl) ether of bisphenol A, ethoxylated bisphenol A diacrylate, 2- (1-naphthyloxy) ethyl acrylate, o -Biphenyl methacrylate, o-biphenyl acrylate and the like.

Specific examples of the monomer of the ester of the aliphatic polyhydric alcohol compound and the unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, and 1,3.
-Butanediol diacrylate, 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 triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol diacrylate Pentaerythritol Sa, sorbitol triacrylate, sorbitol tetraacrylate,
There are 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 itaconic acid esters, ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,
4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate, sorbitol tetritaconate, and the like.

As the crotonic acid ester, ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate,
And 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.

[0021] As another example, Japanese Patent Publication No. 48-417
Polyisocyanate compounds having two or more isocyanate groups in one molecule as described in 08 JP following general formula _{CH 2 = C (R) COOCH} 2 CH (R ') OH ( wherein R, R' is hydrogen or 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 2-30490 A, 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-methacryloyloxyethyl) 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 Polymer 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,

[0027]

Embedded image

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

[0029]

Embedded image

(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) manufactured by K.K.

Next, as the photopolymerization initiator in the initiator system, 1,3-di (t-butyldioxycarbonyl) benzophenone and 3,3 ', 4,4'-tetrakis (t-
(Butyldioxycarbonyl) benzophenone, N-phenylglycine, 2,4,6-tris (trichloromethyl) -s-triazine, 3-phenyl-5-isoxazolone, 2-mercaptobenzimidazole, and imidazole dimers Etc. are exemplified.

From the viewpoint of stabilizing the recorded hologram, the photopolymerization initiator is preferably decomposed after hologram recording. For example, organic peroxides are preferable because they are easily decomposed by irradiation with ultraviolet rays.

The sensitizing dyes include thiopyrylium salt dyes having absorption light at 350 to 600 nm, merocyanine dyes, quinoline dyes, styrylquinoline dyes, ketocoumarin dyes, thioxanthene dyes, xanthene dyes, oxonol dyes. Examples thereof include dyes, cyanine dyes, rhodamine dyes, thiopyrylium salt dyes, pyrylium ion dyes, and diphenyliodonium ion dyes. A sensitizing dye having absorbed light in a wavelength region of 350 nm or less or 600 nm or more may be used.

As the matrix polymer which is a binder resin, polymethacrylic acid ester or its partial hydrolyzate, polyvinyl acetate or its hydrolyzate, polyvinyl alcohol or its partial acetalization product, triacetyl cellulose, polyisoprene, polybutadiene. , Polychloroprene, silicone rubber, polystyrene, polyvinyl butyral, polychloroprene, polyvinyl chloride, chlorinated polyethylene, chlorinated polypropylene, poly-N-vinylcarbazole or its derivative, poly-N-vinylpyrrolidone or its derivative, styrene and anhydrous Maleic acid copolymer or its half ester, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, acrylamide, acrylonitrile, ethylene, propylene, Vinyl, copolymers and at least one polymerizable component copolymerizable monomers groups such as vinyl acetate or mixtures thereof, are used. Preferably polyisoprene, polybutadiene, polychloroprene, polyvinyl alcohol, polyvinyl acetal which is a partial acetalization product of polyvinyl alcohol,
Examples thereof include polyvinyl butyral, polyvinyl acetate, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer and the like, or a mixture thereof.

The stabilizing step of the recorded hologram includes the step of monomer transfer by heating, for which the matrix polymers preferably have a relatively low glass transition temperature to facilitate monomer transfer. It needs to be one.

The photopolymerizable compound is the binder resin 1
It is used in a proportion of 10 parts by weight to 1000 parts by weight, preferably 10 parts by weight to 100 parts by weight, relative to 00 parts by weight.

The photopolymerization initiator is used in an amount of 1 to 10 parts by weight, preferably 5 to 10 parts by weight, based on 100 parts by weight of the binder resin.

The sensitizing dye is 0.01 to 1 part by weight, preferably 0.0 to 100 parts by weight of the binder resin.
It is used in a proportion of 1 part by weight to 0.5 part by weight.

In addition, examples of the photosensitive material component include a plasticizer, glycerin, diethylene glycol, triethylene glycol, and various nonionic surfactants, cationic surfactants, and anionic surfactants.

These hologram recording materials include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, benzene, toluene, xylene, chlorobenzene, tetrahydrofuran, methyl cellosolve,
Ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, ethyl acetate, 1,4-dioxane, 1,2-dichloroethane, dichloromethane, chloroform, methanol, ethanol, isopropanol, or the like, or a mixed solvent thereof is used. % ~
The coating liquid is 25%. In addition, such a coating liquid,
For example, Omnidex 352 and 706 manufactured by Tupon may be used.

The hologram recording layer has a film thickness of 1 μm to 100 μm, preferably 4 μm to 20 after the coating liquid is dried on the substrate.
It is formed by coating at μm.

The base material has a thickness of 0.01 to 100 m.
m, preferably a glass plate, an acrylic plate, a polycarbonate plate, a polyethylene plate, a polypropylene plate, a polyethylene terephthalate plate, a polystyrene plate and the like having a size of 1 to 5 mm. Preferably, a glass substrate, an acrylic substrate, or a polycarbonate substrate having sufficient mechanical strength, low birefringence, and high transparency is used.

A protective layer is provided on the hologram recording layer. As the protective film, a polyethylene terephthalate film having a thickness of 0.001 to 10 mm, preferably 0.01 to 0.1 mm, a polyethylene film, a polypropylene film, an acrylic film, a polyacetylose film, a cellulose acetate butyrate film, etc. A good transparent resin film may be formed by bonding with a rubber roller, or a film forming material such as triacetylose, polyvinyl alcohol, polymethyl methacrylate may be applied by spin coating.

Next, the hologram forming method of the present invention will be described. The hologram recording medium produced as described above is similar to the conventional method for producing a dry hologram,
(1) By the Lippmann hologram forming apparatus, two light beams of laser light, for example, argon light, laser light (wavelength 5
14.5 nm) or the like to record interference fringes on the hologram recording layer, (2) ultra high pressure mercury lamp, high pressure mercury lamp,
Carbon arc, xenon arc, 0.1~10000mJ / cm ² from a light source such as a metal halide lamp, preferably decomposing the photopolymerization initiator by UV irradiation 10~1000mJ / cm ^2, (3) heat treatment (e.g., A stable hologram is obtained through the steps of sequentially diffusing and moving the photopolymerizable compound at 120 ° C. for 120 minutes.

According to the present invention, after the above steps, the hologram recording layer is irradiated with light having an absorption wavelength peculiar to the sensitizing dye remaining in the hologram recording layer to cause the sensitizing dye to fade.

The fading step is, for example, 350 nm to 6 nm.
In order to bleach the sensitizing dye having absorption in the wavelength region of 00 nm, depending on the amount of the dye, it may be preferable to expose the fluorescent light and natural light having an intensity of 500 lux for 20 hours to 60 hours. It is possible to easily fade the coloring in the hologram recording layer and increase the transmittance to 93%. In addition, in order to discolor the sensitizing dye having absorption in the wavelength range of 350 nm or less, or 600 nm or more, similarly, light in the corresponding wavelength range may be irradiated. Hereinafter, the present invention will be described with reference to examples. In addition, "part" in an Example shows a weight part.

[0047]

[Example 1] Methyl methacrylate + vinylcarbazole (weight ratio 1: 1) ... 29 wt% N-phenylglycine ... 4 wt% Polyvinyl alcohol + polyvinyl acetate (weight ratio 1: 1)・ ・ ・ 66.9 wt% ・ Rhodamine 6G (orange color, absorption wavelength region at 460 nm to 530 nm) ・ ・ ・ 0.1 wt% was dissolved in a mixed solvent of methyl ethyl ketone: toluene = 75: 25 to obtain a solid content of 20. % Coating solution with a thickness of 3.0
After coating and drying on a glass substrate (Suzuki Glasstech Co., Ltd.) having a thickness of 25 mm by a spin coating method to form a coating film having a thickness of 25 μm, a triacetyl cellulose film having a thickness of 50 μm is formed on the recording layer surface (Fuji Photo Film Co., Ltd.). A colorless recording medium (manufactured by KK) was laminated to obtain a hologram recording medium.

On this hologram recording medium, a transmissive hologram diffraction grating was produced by a Lippmann hologram forming apparatus (manufactured by Du-Pont, Omnidex duplicator) using a 514 nm Ar laser.

Then, using a high pressure mercury lamp, 1 mW / cm
² Irradiate with UV light for 100 seconds,
Heated for minutes.

The hologram recording layer thus obtained was still in an orange colored state and had optical characteristics of 514n.
When measured with an m laser, the transmittance was 80% and the diffraction efficiency was 76%.

Next, this hologram was irradiated with a fluorescent lamp of 500 lux (435 to 620 nm) for 60 hours, and almost all its coloring disappeared. When the optical characteristics were measured again with a 514 nm laser, the transmittance was 9
The diffraction efficiency was 5%, the diffraction efficiency was 90%, and the diffraction efficiency was 1.2 times.

[0052]

Example 2 Omnidex 352 (manufactured by DuPont, colored orange) ... 100 parts Breakdown Sensitive material component ... 25 parts Methyl ethyl ketone ... 55 parts Toluene ... 20 parts with a thickness of 3. A glass substrate having a thickness of 0 mm (Suzuki Glass Tech Co., Ltd.) is applied by spin coating and dried to give a thickness of 25.
After forming a coating film of μm, the film thickness of 50 μm on this recording layer surface
A triacetyl cellulose film (manufactured by Fuji Photo Film Co., Ltd., colorless and transparent) was laminated to obtain a hologram recording medium.

On this hologram recording medium, a transmissive hologram diffraction grating was produced by using a Lippmann hologram forming apparatus (manufactured by Du-Pont, Omnidex duplicator) and Ar laser of 514 nm.

Then, using a high pressure mercury lamp, 1 mW / cm
² Irradiate with UV light for 100 seconds,
Heated for minutes.

The hologram recording layer thus obtained was still in a state of being colored orange and had optical characteristics of 514n.
When measured with an m laser, the transmittance was 80% and the diffraction efficiency was 76%.

Next, this hologram was irradiated with a fluorescent lamp of 500 lux (435 to 620 nm) for 60 hours, and its coloring almost disappeared. When the optical characteristics were measured again with a 514 nm laser, the transmittance was 9
The diffraction efficiency was 5%, the diffraction efficiency was 90%, and the diffraction efficiency was 1.2 times.

[0057]

[Comparative Example] In Example 1, the hologram that had not been subjected to the color fading treatment was allowed to stand in natural light for 7 days, and the transmittance was 95%, and the coloring disappeared constantly, but the diffraction efficiency was increased to 70%. Diminished. If left in natural light,
The difference in refractive index (Δn) between the polymerized portion and the non-polymerized portion is reduced by the ultraviolet rays contained in the natural light, which causes a problem such as a decrease in diffraction efficiency or a wavelength shift.

[0058]

According to the hologram forming method of the present invention, a hologram having a high light transmittance and an improved diffraction efficiency in a dry hologram recording layer can be easily and quickly produced.

Claims (2)

[Claims] 1. A hologram is recorded on a dry hologram recording layer comprising a matrix polymer, a photopolymerizable compound, a photopolymerization initiator and a sensitizing dye, and then the absorption wavelength light peculiar to the sensitizing dye is irradiated to the dry hologram recording layer. A method of forming a hologram, which comprises performing a step of fading a sensitizing dye. 2. The hologram forming method according to claim 1, wherein the hologram is a transmission type volume phase hologram.