JP2000112322A - Transparent hologram recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a transparent hologram recording material which has high sensitivity to visible rays or electron beams, excellent hologram characteristics and especially which is colorless and excellent in transparency by using each specified material for a photopolymn. initiator, a sensitizer and an assistant. SOLUTION: This hologram recording material consists of the following compds. Namely, the compds. are cation polymerizable thermosetting epoxy oligomers soluble in a solvent and having at least one glycidyl group in the unit structure, a compd. which is a liquid at normal temp. and normal pressure and has >=100 deg.C boiling temp. at normal pressure and at least one radical polymerizable ethylenic unsatd. bond. an aromatic onium salt which produces radicals to activate radical polymn. and which produces Bronsted acid or Lewis acid to activate cation polymn. when exposed to actinic radiation and moreover, a compd. selected from among 3-substd. coumarin compds, and p-amino unsatd. ketone compds. as a sensitizing dye. The recording material contains a quaternary boron salt as an assistant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hologram recording material used for forming a volume phase hologram, which has high sensitivity to visible light, especially argon laser light or electron beam, weather resistance and storage stability. The present invention relates to a transparent hologram recording material which is excellent in hologram characteristic values such as resolution and diffraction efficiency, and is particularly colorless and excellent in transparency.

[0002]

2. Description of the Related Art Conventionally, holograms have been used for covers of books, magazines, etc., POP displays, gifts, etc. because of their excellent design and decorative effects, since holograms can reproduce a three-dimensional stereoscopic image. Also, since holograms can be said to be equivalent to information in submicron units, securities,
It is also used for forgery prevention marks such as credit cards. In particular, the volume phase hologram can modulate the phase without absorbing the light beam passing through the image by forming spatial interference fringes having different refractive indexes instead of optical absorption in the hologram recording medium. Therefore, in recent years, in addition to display applications, holographic lenses for optical disks, hologram color filters for liquid crystal projectors, and POS scanners have been studied as light control elements. Further, application to a hologram optical element (HOE) typified by a head-up display (HUD) mounted on an automobile or an optical computer is expected.

Incidentally, a volume phase type hologram recording material is required to be sensitive to laser light having a visible oscillation wavelength with high sensitivity and to exhibit high resolution. Further, when actually used for forming a hologram, it is required that characteristics such as the diffraction efficiency of the hologram, the reproducibility of the wavelength of the reconstructed light, and the bandwidth (half-width of the reconstructed light peak) meet the purpose. In particular, the hologram recording material for HOE has a diffraction efficiency of 90% or more at a spatial frequency of 5000 to 6000 lines / mm,
The half width (band width) of the peak of the reproduction light is 20 to 30 n
m, the peak wavelength of the reproduction wavelength is desirably within 5 nm from the imaging wavelength, and it is also required that the storage stability be excellent over a long period of time.

[0004] The general principle of hologram fabrication is described in several literatures and technical books, for example, Chapter 2 of “Holographic Display” (edited by Junpei Tsujiuchi; Sangyo Tosho). According to these, generally, a photosensitive recording medium, for example, a photographic dry plate, is placed at a position where one of two coherent laser beams of a light beam is irradiated onto a recording object and the light totally reflected therefrom can be received. The recording medium is irradiated directly with the other coherent light in addition to the reflected light from the object without hitting the object. The light reflected from the object is referred to as target light, and the light directly illuminating the medium is referred to as reference light, and interference fringes between the reference light and the target light are recorded as image information.
Next, when the processed recording medium is exposed to light and observed at an appropriate eye position, the light from the illumination light source emits the wavefront of the reflected light that first arrived at the recording medium from the object during recording. Is diffracted by the hologram so as to reproduce the object, and as a result, an object image similar to the real image of the object is observed three-dimensionally. A hologram formed by causing the reference light and the target light to enter the recording medium from the same direction is known as a transmission hologram. On the other hand, holograms formed by making incident from opposite sides of a recording medium are generally known as reflection holograms. Transmission holograms are disclosed, for example, in US Pat.
No. 06327, U.S. Pat. No. 3,894,787, and the like. Further, a reflection type hologram is disclosed in, for example, US Pat.
It can be produced by a known method disclosed in JP-A-532406.

A value for comparing a hologram formed as an image is refractive index modulation. This is because, when the recording medium is directly irradiated with the two light beams at the same angle to the medium and a diffraction grating is produced, the ratio of the incident light diffracted by the diffraction grating, that is, the diffraction efficiency and the recording medium It is a value specified from the thickness. Refractive index modulation is a quantitative measure of the change in refractive index that occurs in exposed and unexposed areas of a volume hologram, that is, areas where light interferes and strengthens, and is described by H. Kogelnik. Theoretical formula [Bell. Svt. Tech. J. , 48,2
909, (1969). ]. Generally, reflection holograms have higher resolution than transmission holograms, that is, recording is difficult because of the large number of interference fringes formed per mm, and it is difficult to obtain high refractive index modulation.

As a recording material for such a volume phase type hologram, a photosensitive material based on a bleached silver salt and a gelatin based dichromate has been generally used. Gelatin based dichromate photosensitive materials are the most widely used materials for recording volume phase holograms because of their high diffraction efficiency and low noise characteristics. However, this photosensitive material has a short shelf life and must be prepared each time it is produced. In addition, since the wet development is performed, the hologram is deformed in the process of swelling and shrinking the gelatin necessary for producing the hologram. Therefore, there is also a problem that reproducibility is poor. Further, the silver salt photographic material requires complicated processing after recording, and this is not a photographic material satisfactory from the viewpoint of stability and workability. Further, all of these photosensitive materials have a problem that they are inferior in environmental resistance characteristics, for example, moisture resistance and weather resistance.

On the other hand, it has excellent environmental resistance and
A hologram recording material using poly-N-vinyl carbazole is a material having characteristics that a hologram recording material should have such as high resolution and high diffraction efficiency. For example, a hologram recording material comprising a cyclic cis-α-dicarbonyl compound as a crosslinking agent and a sensitizer (JP-A-60-45)
No. 283), a hologram recording material comprising 1,4,5,6,7,7-hexachloro-5-norbornene-anhydro-2,3-dicarboxylic acid and a dye (JP-A-60-227).
No. 280), a hologram recording material comprising 2,3-norbornanedione and thioflavin (JP-A-60-26)
No. 0080) and a hologram recording material composed of Thioflavin T and iodoform (Japanese Patent Application Laid-Open No. Sho 62-123489). Since these hologram recording materials also require wet development, they require complicated processing steps and have a problem of poor reproducibility. In addition, since it is a photosensitive material containing poly-N-vinylcarbazole as a main component, it is chemically stable, has high resolution, and has excellent environmental resistance, but poly-N-vinylcarbazole is easily crystallized and very whitened. However, there is a problem that reproducibility of transparency is poor and a solvent is also limited. Further, further improvement in sensitivity characteristics is desired.

As a material which can be photocured with high sensitivity, a photocurable resin composition used in combination with a 3-ketocoumarin and a diaryliodonium salt, which are constituents of a photopolymerization initiator (Japanese Patent Application Laid-Open No. 60-88005). A hologram recording material comprising a combination of the photopolymerization initiator and polymethyl methacrylate as a supported polymer (Japanese Patent Laid-Open No.
No. 31590) has been proposed, and although it is chemically stable and has high resolution and high sensitivity, the gap is formed by wet processing, so that the dispersion of the peak wavelength of the reproduction wavelength and the half width of the peak wavelength are increased. When developing and developing,
Since the carrier polymer is slightly dissolved in the swelling solvent, there is a problem that uneven development is likely to occur. Furthermore, since there are many voids in the hologram, there is a problem that heat resistance and heat pressure resistance are poor.

In order to solve such a problem, photopolymerizable photosensitive materials capable of producing a hologram in one processing step without wet processing are disclosed in US Pat. No. 3,993,485 and US Pat. No. 3,658,526. I have. The former includes two types of photosensitive materials. As a first example, a combination of two polymerizable unsaturated ethylenic monomers having different reactivity and refractive index and a photopolymerization initiator, for example, cyclohexyl methacrylate, N-vinyl This is a photosensitive resin composition comprising carbazole and benzoin methyl ether, which can be hologram-recorded by sandwiching it between two glass plates and exposing it to hologram with a two-beam optical system. Further, as a second example, a polymerizable unsaturated ethylenic monomer having a similar refractive index, an unsaturated ethylenic monomer acting as a cross-linking agent when polymerized, and a refractive index different from those of the two monomers are used. 4 components of a non-reactive compound and a polymerization initiator, such as butyl methacrylate,
This is a photosensitive resin composition comprising ethylene glycol dimethacrylate, 1-phenylnaphthalene and benzoin methyl ether and capable of producing a hologram in the same manner as in the first example. Regardless of the photosensitive resin composition used, polymerization of highly reactive monomers progresses in the portion where the light intensity of the interference fringes formed by the two-beam optical system is increased, and a concentration gradient of the monomers is generated. Higher monomers diffuse into areas of higher light intensity, and less reactive monomers or non-reactive compounds diffuse into areas of lower light intensity. In this way, the interference fringes are recorded with a difference in the refractive index, and a volume phase hologram is formed.

However, such a conventional photosensitive resin composition for hologram recording has the following problems. That is, in the case of the first example, even a monomer having low reactivity undergoes a certain degree of polymerization, and high refractive index modulation cannot be obtained. In the second example, 1-phenylnaphthalene, which is a non-reactive compound, exists in the system as a low molecular weight compound even after completion of the hologram, and has no storage stability. In each case, the mixture is a low-molecular-weight mixture, and has low viscosities, so that there are many problems in workability and reproducibility, such as difficulty in sandwiching between substrates and formation of a thick film.

US Pat. No. 3,658,526 discloses a method for producing a stable hologram comprising a hologram recording material in which a liquid monomer, a photopolymerizable ethylenic monomer and a photopolymerization initiator are blended in a polymer matrix. Thus, a single exposure to actinic radiation results in a permanent volume phase hologram. The hologram formed is fixed by subsequent full irradiation with actinic radiation. The hologram recording material disclosed here is intended to provide many advantages in terms of workability and reproducibility, but its diffraction efficiency is low. In this hologram recording material, the refractive index modulation of the completed hologram is in the range of 0.001 to 0.003. As a result, the reproduced image of the formed hologram has only a limited brightness. Although it is possible to provide some brightness by increasing the thickness of the hologram recording layer, this solution has resulted in the manufacturer using a large amount of hologram recording material, and has also resulted in certain media, such as in-vehicle applications. It hinders the case where the device is fixed in a laminated glass such as a head-up display. It should also be noted that the holograms formed by this generally cause a decrease in diffraction efficiency due to long-term storage.

As an improvement technique including a method for manufacturing a hologram recording material disclosed in US Pat. No. 3,658,526, US Pat. No. 4,942,112, US Pat. No. 5,098,803, Japanese Patent Laid-Open No. 2-3081, and US Pat. JP-A-2-3082 is disclosed. The basic composition is a thermoplastic resin, a polymerizable unsaturated ethylenic monomer and a photopolymerization initiator.To improve the refractive index modulation, an aromatic ring is added to either the thermoplastic resin or the polymerizable unsaturated ethylenic monomer. It is devised to have a refractive index difference by using a compound having the same. However, as disclosed in U.S. Pat. No. 3,658,526, the use of a high molecular weight resin as a binder matrix limits the diffusibility of the monomer during exposure and requires a large amount of exposure. And high diffraction efficiency cannot be obtained. Further, in order to improve this point, a non-reactive plasticizer is added. However, this use causes a problem in the film strength of the formed hologram and also causes the non-reactive plasticizer to have a non-reactive plasticizer. Even after completion, it is present in the system as a low molecular weight compound and has no storage stability. In addition, since the carrier holding this is a thermoplastic resin, it has a drawback of poor heat resistance.

On the other hand, according to Japanese Patent Application Laid-Open No. Hei 5-107999, which is an improvement technique for the above-mentioned disadvantage, a cation polymerizable monomer and a cation polymerization initiator are blended in place of the plasticizer in the above patent. The problem caused by the non-reactive plasticizer remaining after hologram formation is solved. However, a considerable amount of light irradiation is required for fixing after hologram formation, and a low molecular weight cationic polymerizable monomer is diffused during fixing, resulting in distortion of the formed hologram and obtaining high diffraction efficiency. Can not do. Further, similarly to the prior art, since the carrier holding the carrier is a thermoplastic resin, there is a disadvantage that the heat resistance is poor. Furthermore, in a system that does not use a thermoplastic resin as a carrier for holding, many problems remain in workability and reproducibility, such as difficulty in sandwiching between substrates due to low viscosity and difficulty in forming a thick film. I have.

Further, a photosensitive resin composition for hologram recording comprising an epoxy resin, a radically polymerizable unsaturated ethylenic monomer and a photoradical polymerization agent is disclosed in Japanese Patent Laid-Open No. 5-94.
No. 014. As can be seen from the examples, two types of epoxy resins are used. However, when an ultraviolet curable epoxy resin is used, complicated work such as performing radical polymerization and cationic polymerization with light in different wavelength ranges is required. In addition, in order to adjust the diffusibility of the monomer, fine adjustment such as increasing the viscosity by pre-exposure is required, and workability and reproducibility are difficult. Further, when a thermosetting epoxy resin and a curing agent are used, the workability is extremely poor because a considerable amount of ultraviolet curing and heating time are required for curing the epoxy resin for fixing. In addition, high diffraction efficiency cannot be obtained with the improved technology disclosed herein.

[0015]

As described above, in a photopolymerization type photosensitive material capable of forming a hologram in a single processing step without wet processing, the polymerization of a monomer for obtaining a refractive index modulation is performed. In addition, there are problems such as dispersibility, storage stability due to the addition of a monomer-supporting carrier and a non-reactive additive, and the workability of hologram production, diffraction efficiency of the obtained hologram, and transparency. However, it has not been possible to obtain hologram recording materials having excellent hologram characteristics such as reproducibility, and there is still a need for improved photopolymerizable compositions for hologram recording, especially in hologram optical elements using them. Sex is growing. When the application of the hologram recording material as a hologram optical element is studied, it is particularly important that the material is colorless and transparent and has high diffraction efficiency. However, to produce a hologram using a hologram recording material, a coherent light such as a laser beam, particularly a light source in the visible light region is used. Therefore, a sensitizing dye for absorbing this light and initiating polymerization is used. There is a need. Therefore, if absorption and coloring by the sensitizing dye remain after the hologram is produced, it becomes a very important problem in examining the application as a hologram optical element. There are various ways to solve this problem,
One method is to reduce the amount of sensitizing dye. By reducing the amount of the dye, the transparency of the hologram optical element is improved, but the sensitivity is reduced accordingly. Although an increase in the sensitivity is expected by increasing the amount of the sensitizing dye, coloring of the hologram optical element poses a problem. As described above, it is difficult to achieve both the transparency and the sensitivity of the hologram optical element, and solving this problem has been a major issue.

[0016]

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that specific materials for a photopolymerization initiator, a sensitizing dye, and an auxiliary in a hologram recording material are determined. By selecting the hologram recording material, it is found that the hologram recording material has good sensitivity to coherent light having an oscillation source in a visible light region (400 nm or more) (in particular, the transparency of the hologram recording material can be improved). It is a thing.

That is, the invention of claim 1 comprises (A) a solvent-soluble, thermosetting epoxy oligomer capable of cationic polymerization having at least one glycidyl group in a unit structure, and (B) a liquid at room temperature and normal pressure. And boiling point at normal pressure
A compound having at least one radically polymerizable ethylenically unsaturated bond having a temperature of at least 00 ° C., (C) a radical species that activates radical polymerization when exposed to actinic radiation, and a brane that activates cationic polymerization An aromatic onium salt generating a Sted acid or a Lewis acid; and (D) a 3-substituted coumarin compound represented by the following general formula (1):

[0018]

Embedded image

(Wherein R ₁ , R ₂ , R ₃ and R ₄ are hydrogen, an alkyl group, an alkoxy group, an alkylamino group, a dialkylamino group, a cyano group, or a condensed or heterocyclic ring system of two) A is an aryl group, a heterocyclic group, a group represented by the general formula (2),

[0020]

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Is shown. R ₅ represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, or a heterocyclic group. ) And / or p- represented by the following general formula (3).
Amino unsaturated ketone compounds,

[0022]

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Wherein m and n are each 0 or 1, and R ₆ and R ₇ are a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, or CH ₂ COOR ₁₁ (where R ₁₁ is a hydrogen atom or a carbon atom Represents 1 to 5 alkyl groups, alkali metal, ammonium, amine), or C ₂ H ₄ CF ₃ , C _{2
H 4 I, C 2 H 4} Br, C 2 H 4 Cl, C 2 H 4 F, C 2 H 4 C
_{N, C 2 H 4 NO 2} . R ₈ is alkylene of 1 to 5 carbon atoms which may form a ring together with bonded to a carbonyl group and methylidine group or R ₉ - ylidine group, R ₉ is a carbon atom, a substituent or unsubstituted phenyl group or, R ₈
And a group forming indanone or tetralone together with a carbonyl group, a group represented by the general formula (4),

[0024]

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(Provided that R ₁₂ and R ₁₃ are a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, or CH ₂ COOR
₁₄ (where R ₁₄ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, an alkali metal, ammonium, or an amine), or C ₂ H ₄ CF ₃ , C ₂ H ₄ I, C ₂ H ₄ Br, C ₂
H ₄ Cl, C ₂ H ₄ F, C ₂ H ₄ CN, and C ₂ H ₄ NO ₂ . )] A holographic recording material comprising a sensitizing dye selected from the group consisting of a quaternary boron salt represented by the following general formula (5) as an auxiliary agent (E):

[0026]

Embedded image

(Wherein R ₁₅ , R ₁₆ , R ₁₇ and R ₁₈ each independently represent an alkyl group, an aryl group, an allyl group, an alkoxyl group, an alkenyl group, an alkynyl group, a silyl group,
Z ⁺ represents a quaternary ammonium cation, a quaternary pyridinium cation, a quaternary quinolinium cation, a phosphonium cation, a sulfonium cation, an oxosulfonium cation, an iodonium cation or a metal cation. A hologram recording material characterized by containing:

According to a second aspect of the present invention, there is provided the hologram recording material according to the first aspect, wherein when exposed to actinic radiation, a radical species that activates radical polymerization and a Bronsted acid or Lewis that activates cationic polymerization. The aromatic onium salt (C) generating an acid is a diaryliodonium salt.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
FIG. 1 is a schematic diagram illustrating the configuration of a hologram recording medium made of the hologram photosensitive recording material of the present invention.
FIG. 2 is a schematic explanatory view illustrating a two-beam optical system for hologram imaging.

(A) Examples of the thermosetting epoxy oligomer which is soluble in a solvent and has at least one glycidyl group in a unit structure and which can be cationically polymerized include bisphenol A, bisphenol AD, bisphenol B, bisphenol AF, bisphenol S, and brominated compounds. Bisphenol A, novolak, o-cresol novolak, p-alkylphenol novolak, hydrogenated bisphenol A,
The following epoxy compounds formed by the condensation reaction of various phenol compounds such as hydrogenated bisphenol AD, hydrogenated bisphenol B, hydrogenated bisphenol AF, hydrogenated bisphenol S, and hydrogenated brominated bisphenol A with epichlorohydrin are exemplified. be able to. However, the present invention is not limited to these.

[0031]

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(Where n = 1 to 20)

[0033]

Embedded image

(Wherein, R represents an alkyl group, and n = 1
-20. )

[0035]

Embedded image (Where n = 1 to 20)

The thermosetting resin has a molecular weight of 900 to 6
000 is preferable, and if it is smaller than this, the film-forming property deteriorates and uniform coating cannot be performed. Further, a molecular weight larger than this range generally makes synthesis difficult. The epoxy equivalent of the thermosetting resin is preferably in the range of 400 to 6000, otherwise good cationic polymerization does not proceed.

Component (B) used in the present invention is a compound having at least one radically polymerizable ethylenically unsaturated bond which is liquid at normal temperature and pressure and has a boiling point of 100 ° C. or higher at normal pressure. It contains at least one ethylenically unsaturated bond therein, contains a polyfunctional vinyl monomer in addition to a monofunctional vinyl monomer, and may be a mixture thereof. Specifically, (meth) acrylic acid, itaconic acid, maleic acid,
(Meth) acrylamide, diacetone acrylamide,
High-boiling vinyl monomers such as 2-hydroxyethyl (meth) acrylate, and further, aliphatic polyhydroxy compounds such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol,
Tripropylene glycol, tetrapropylene glycol, neopentyl glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, trimethylolpropane Di- or poly (meth) acrylates such as pentaerythritol, dipentaerythritol, sorbitol, mannitol, or alicyclic polyhydroxy compounds, for example,
Mono- or di (meth) acrylates such as dicyclopentanol, dicyclopentenol, and tricyclodecane dimethylol are exemplified, and polyethylene glycol di (meth) acrylate or polypropylene glycol di (meth) is preferable. Acrylates may be mentioned, but are not limited thereto.

The component (C) of the present invention includes a photoinitiator system which activates radical polymerization and cationic polymerization when exposed to actinic radiation. The aromatic initiator which simultaneously generates a radical species and a Bronsted acid or a Lewis acid upon irradiation with light is used. As the onium salt, a diaryliodonium salt or the like is preferable. Examples of the diaryliodonium salt used in the present invention include Macromolecules, 10, 1307.
(1977). And diphenyliodonium, ditolyliodonium, phenyl (p-anisyl) iodonium, bis (m-nitrophenyl) iodonium, bis (pt-butylphenyl) iodonium, bis (p-chlorophenyl) iodonium, etc. Iodonium chloride, bromide or tetrafluoroborate salt, hexafluorophosphate salt,
Hexafluoroarsenate salts and the like can be mentioned, but not limited thereto.

Specific examples of the 3-substituted coumarin compound represented by the general formula (I), which is the component (D) of the present invention, include 7-diethylamino-3- (2-benzothiazyl) coumarin and 7-diethylamino-3. -(2-benzimidazolyl) coumarin, 7-diethylamino-3-benzoylcoumarin, 7-diethylamino-3-thienoylcoumarin, 7-diethylamino-3,3'-carbonylbiscoumarin, 3,3'-carbonylbis (7- Diethylaminocoumarin), 9,9′-carbonylbis (1,2,4,5-tetrahydro-3H, 6H, 10H
[I] benzopyrano [9,9a, 1-gh] quinolazin-10-one) and the like, but are not limited thereto. Methods for synthesizing these compounds are described in Chemical Reviews 361 (194).
5) and Tetrahedron 38 (9) 120
3-1211 (1982).

The component (D) of the present invention has the above general formula (I)
Specific examples of the p-aminophenyl unsaturated ketone compound represented by I) include 2,5-bis (4'-diethylaminobenzylidene) cyclopentanone and 2,5-bis (4'-dimethylaminobenzylidene) cyclopentanone Non, 2,6-bis (4'-diethylaminobenzylidene) cyclohexanone, 2,6-bis (4'-dimethylaminobenzylidene) cyclohexanone, 2,5-bis (4'-dimethylaminocinnamylidene) cyclopentanone, 2,6-bis (4′-dimethylaminocinnamylidene) cyclohexanone, 1,3-bis (4′-dimethylaminobenzylidene) acetone, 2- (4′-diethylaminobenzylidene) -1-indanone, 2- (9 '
-Durolylidene) -1-indanone, 2- (4'-diethylaminobenzylidene) -1-tetralone, 4'-
Diethylamino-2'-methylbenzylidene-acetophenone, 2,5-bis (4'-N-ethyl-N-carbomethoxymethylaminobenzylidene) cyclopentanone, and its sodium salt, 2,5-bis (4'-N
-Methyl-N-cyanoethylaminobenzylidene) cyclopentanone, 2,5-bis (4'-N-ethyl-N-
Chloroethylaminocinnamylidene) cyclopentanone, 2,6-bis (4′-N-cyanoethylaminobenzylidene) cyclohexanone, 2- (4′-N-ethyl-N-carboxymethylaminobenzylidene) -1-indanone, 2- (4'-N-ethyl-N-carboxymethylaminobenzylidene) -1-tetralone, 2-
Examples thereof include (4′-ethyl-N-cyanoethylaminobenzylidene) -1-indanone, and a sodium salt thereof, but are not limited thereto.

As the quaternary boron compound represented by the general formula (5) which is the component (E) of the present invention, specific examples of the anion portion include n-butyltriphenyl borate and
n-octyl triphenyl borate, n-dodecyl triphenyl borate, sec-butyl triphenyl borate, t-butyl triphenyl borate, benzyl triphenyl borate, n-butyl trianisyl borate, n
-Octyl trianisyl borate, n-dodecyl trianisyl borate, n-butyl tri (4-tolyl) borate, n-butyl tri (2-tolyl) borate, n-butyl tri (4-t-butylphenyl) borate, n-butyl tri ( 4-fluoro-2-methylphenyl) borate, n-butyl tri (4-fluorophenyl) borate, n-butyl trinaphthyl borate, triphenylsilyl triphenyl borate, diphenylmethyl silyl triphenyl borate, dimethylphenyl silyl triphenyl borate, Examples include, but are not limited to, trimethylsilyl triphenyl borate, tetra-n-butyl borate, di-n-butyl diphenyl borate, tetrabenzyl borate, and the like.

Specific examples of the cation moiety include tetramethylammonium, tetraethylammonium, tetra-n-butylammonium, tetraoctylammonium, methylquinolinium, ethylquinolinium, methylpyridinium, ethylpyridinium and tetramethylphosphonium. , Tetra-n-butylphosphonium, trimethylsulfonium, triphenylsulfonium, trimethylsulfoxonium, diphenyliodonium, di (4-t-butylphenyl) iodonium, lithium cation, sodium cation, and the like, but are not limited thereto. It is not what is done. These anion part and cation part can be used in the present invention in any combination.

When the transparent hologram recording material of the present invention is coated on a support or the like, for example, toluene, xylene, chlorobenzene, chloroform, dichloroethane,
Dichloroethylene, trichloroethylene, methyl isobutyl ketone, dioxane, tetrahydrofuran, isopropanol, n-butanol, 2-methoxyethanol, 2-methoxyethyl acetate, propylene glycol monomethyl ether, 3-methoxypropanol,
A suitable solvent such as 3-methoxypropyl acetate, methyl ethyl ketone, acetone or the like can be used alone or dissolved in a mixed solvent in which these are appropriately combined.

Further, in the transparent hologram recording material of the present invention, various additives can be used in combination in order to solve various problems in practical use. For example, for the purpose of preventing thermal polymerization during storage, p-methoxyphenol,
Addition of thermal polymerization inhibitor such as hydroquinone, catechol, phenothiazine, addition of chain transfer agent such as amine, thiol, disulfide, etc. for the purpose of accelerating polymerization, or defoaming agent, leveling agent, plasticizer, antioxidant, Fuel,
An antistatic agent, an antihalation agent and the like can be added.

As described above, the photosensitive solution obtained by appropriately selecting these components and mixing them in an arbitrary ratio is applied to a glass plate or a glass plate using a known coating means such as a spin coater, a roll coater, or a bar coater. A hologram recording medium 1 for normal hologram photography, in which a hologram shown in FIG. 1 is produced, is formed by applying a film on a substrate 2 such as a polycarbonate plate, a polymethyl methacrylate plate, or a polyester film. Further, a protective layer 4 may be provided on the photosensitive layer 3 as an oxygen blocking film. For the protective layer 4, for example, a material equivalent to the above-described substrate 2, or polyolefin, polyvinyl chloride,
It is formed by using a plastic such as polyvinylidene chloride, polyvinyl alcohol or polyethylene terephthalate, or an optically transparent material such as glass, by laminating the photosensitive layer, laminating with an extruder, applying a solution, and the like. . When the photosensitive liquid is applied, it may be diluted with an appropriate solvent as necessary, but in that case, drying is required after application on the substrate. Further, it is desirable to adjust the transmittance of the irradiation light at the time of photographing to be 1% or more.

FIG. 2 is a schematic view for explaining a two-beam optical system for reflection type hologram photographing. A laser beam 6 oscillated from a laser 5 passes through a mirror 7, a beam splitter 8, a spatial filter 9, and a lens 10. The hologram recording medium 1 is irradiated through the hologram recording medium 1. In the present invention, after the hologram is photographed by exposure, the fixing step is performed by dry processing.
Although the present invention is not described in detail and is not shown in the drawings, it is also possible to manufacture a transmission hologram, and a transmission hologram having excellent hologram characteristics can be obtained.

In the step of exposing the interference pattern, the light source suitable for the hologram photosensitive recording material of the present invention may be a light source near a visible light region such as a helium-cadmium laser, an argon laser, a krypton laser, a helium-neon laser, and a semiconductor laser. A coherent light source having an oscillation source in an infrared light region (400 nm or more) can be used, but is not limited thereto.

According to the principle of the present invention, although the mechanism of the initiation of polymerization is not always clear, the onium salt and the quaternary boron salt used in the present invention have an electron-accepting property due to their molecular characteristics. It is considered that the quaternary boron salt has an electron donating property. Electron transfer occurs from the quaternary boron salt to the sensitizing dye that is excited by the absorbed light energy, and the alkyl (or aryl) radical is cleaved from the boron compound converted into a radical by one-electron transfer to function as a polymerization initiator. Or
It is considered that electron transfer from the excited sensitizing dye to the onium salt occurs, and, like the boron compound, the alkyl (or aryl) radical is cleaved to function as a polymerization initiating species. In other words, it is considered that free radical generation by electron donation reaction and free radical generation by electron acceptance reaction are simultaneously generated by light irradiation, and as a result, it is possible to function as a very excellent photopolymerization initiator.

[0049]

Hereinafter, the present invention will be described in more detail with reference to specific examples. <Example 1> Thermosetting epoxy oligomer (bisphenol S type, trade name "EBPS300" manufactured by Nippon Kayaku Co., Ltd.)
100 parts by weight, 50 parts by weight of triethylene glycol diacrylate, 5.0 parts by weight of diphenyliodonium hexafluorophosphate, 0.5 parts by weight of 3,3'-carbonylbis (7-diethylaminocoumarin) and n-
A solution obtained by mixing and dissolving 2.5 parts by weight of butyltriphenylborate-tetrabutylammonium salt in 100 parts by weight of 2-butanone was used as a photosensitive solution. When this photosensitive solution has a thickness of about 20
After coating on a glass substrate using an applicator to form a photosensitive layer to a thickness of μm, the photosensitive layer was covered with a polyvinyl alcohol (PVA) film to prepare a hologram recording medium.

The hologram recording medium was exposed to light using an argon laser (488 nm) as a light source by a two-beam optical system for hologram photography shown in FIG. 2 to form a hologram image, and then subjected to a heat treatment at 100 ° C. for 30 minutes. went.

The diffraction efficiency of the obtained hologram was measured with a spectrophotometer manufactured by JASCO Corporation. In this spectrophotometer, a photomultimeter having a slit having a width of 3 mm can be installed on a circumference having a radius of 20 cm around a sample. The measurement conditions were such that monochromatic light having a width of 0.3 mm was incident on the sample at an angle of 45 degrees, and diffracted light from the sample was detected. The ratio between the largest value other than the specular reflection light and the case where the incident light was directly received without placing the sample was defined as the diffraction efficiency.
Table 1 shows the evaluation results. Further, the transmittance in the visible light region (400-700 nm) was measured using a spectrophotometer,
The lowest transmittance was evaluated as the transparency of the hologram recording material. Table 1 shows the evaluation results.

<Embodiment 2> 3, 3'- in Embodiment 1
Carbonyl bis (7-diethylaminocoumarin) was added to 0.
A hologram was prepared and the diffraction efficiency and transmittance were measured in the same manner as in Example 1 except that the amount was changed from 5 parts by weight to 0.1 part by weight. Table 1 shows the evaluation results.

<Embodiment 3> 3, 3'- in Embodiment 1
Carbonyl bis (7-diethylaminocoumarin) 0.5
A hologram was prepared and diffraction efficiency and transmittance were measured in the same manner as in Example 1 except that the weight part was changed to 0.75 weight part of 7-diethylamino-3- (2-benzimidazolyl) coumarin. Table 1 shows the evaluation results.

Example 4 A hologram was prepared in the same manner as in Example 1 except that the amount of 7-diethylamino-3- (2-benzimidazolyl) coumarin in Example 3 was changed from 0.75 parts by weight to 0.25 parts by weight. It was fabricated and measured for diffraction efficiency and transmittance. Table 1 shows the evaluation results.

<Comparative Example 1-4> In Example 1-4,
A hologram was prepared in the same manner as in Example 1 except that 2.5 parts by weight of n-butyltriphenylborate-tetrabutylammonium salt was not added, and diffraction efficiency and transmittance were measured. Table 1 shows the evaluation results.

[0056]

[Table 1]

A: 3,3'-carbonylbis (7-diethylaminocoumarin) b: 7-diethylamino-3- (2-benzimidazolyl) coumarin

<Embodiment 5> 3, 3'- in Embodiment 1
Carbonyl bis (7-diethylaminocoumarin) was added to 0.
A hologram was prepared in the same manner as in Example 1 except that 5 parts by weight was changed to 0.75 parts by weight of 2,5-bis (4'-diethylaminobenzylidene) cyclopentanone, and diffraction efficiency and transmittance were measured. Table 2 shows the evaluation results.

<Example 6> In the same manner as in Example 1, except that 2,5-bis (4'-diethylaminobenzylidene) cyclopentanone in Example 5 was changed from 0.75 part by weight to 0.25 part by weight. A hologram was prepared and diffraction efficiency and transmittance were measured. Table 2 shows the evaluation results.

Example 7 0.75 parts by weight of 2,5-bis (4'-diethylaminobenzylidene) cyclopentanone in Example 5 was replaced with 0.5 part by weight of 1,3-bis (4'-diethylaminobenzylidene) acetone A hologram was prepared and the diffraction efficiency and transmittance were measured in the same manner as in Example 1 except that the hologram was changed to a part. Table 2 shows the evaluation results.

Example 8 Example 1 was repeated except that 1,3-bis (4'-diethylaminobenzylidene) acetone in Example 7 was changed from 0.5 parts by weight to 0.25 parts by weight.
A hologram was prepared in the same manner as described above, and the diffraction efficiency and transmittance were measured. Table 2 shows the evaluation results.

<Comparative Example 5-8> In Example 5-8,
A hologram was prepared in the same manner as in Example 1 except that 2.5 parts by weight of n-butyltriphenylborate-tetrabutylammonium salt was not added, and diffraction efficiency and transmittance were measured. Table 2 shows the evaluation results.

[0063]

[Table 2]

A: 2,5-bis (4'-diethylaminobenzylidene) cyclopentanone b: 1,3-bis (4'-dimethylaminobenzylidene) acetone

[0065]

The transparent hologram material of the present invention comprises a solvent-soluble, cationically polymerizable thermosetting epoxy oligomer having at least one glycidyl group in a unit structure, and a liquid at normal temperature and pressure and a liquid at normal pressure. A compound having at least one radically polymerizable ethylenically unsaturated bond having a boiling point of 100 ° C. or higher, a radical species for activating radical polymerization when exposed to actinic radiation, and a Bronsted for activating cationic polymerization Colorless by containing an aromatic onium salt generating an acid or Lewis acid, a sensitizing dye comprising a 3-substituted coumarin compound and / or a p-amino unsaturated ketone compound, and a quaternary boron salt as an auxiliary agent To provide a transparent hologram recording material having high transparency, high sensitivity and applicable to hologram optical elements. Kill.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a hologram recording medium made of a transparent hologram recording material of the present invention.

FIG. 2 is a schematic diagram illustrating a two-beam optical system for hologram imaging.

[Explanation of symbols]

 Reference Signs List 1 hologram recording medium 2 substrate 3 photosensitive layer 4 protective layer 5 laser 6 laser beam 7 mirror 8 beam splitter 9 spatial filter 10 lens 11 lens

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H025 AA00 AA01 AA02 AA10 AA11 AB14 AC01 AC08 BC32 BC42 BD03 BE07 CA20 CA27 CA41 CC20 EA10 2K008 AA11 DD13 EE01 FF17

Claims (2)

[Claims] 1. A thermosetting epoxy oligomer which is solvent-soluble and cationically polymerizable and has at least one glycidyl group in a unit structure, and (B) a liquid which is liquid at normal temperature and normal pressure and has a boiling point at normal pressure. A compound having at least one radically polymerizable ethylenically unsaturated bond at a temperature of 100 ° C. or higher, (C) a radical species that activates radical polymerization when exposed to actinic radiation, and a brane that activates cationic polymerization An aromatic onium salt generating a Sted acid or a Lewis acid; and (D) a 3-substituted coumarin compound represented by the following general formula (1): (Wherein R ₁ , R ₂ , R ₃ and R ₄ are hydrogen, an alkyl group, an alkoxy group, an alkylamino group, a dialkylamino group,
A cyano group or two of them may form a fused ring system or a fused heterocyclic system. A is an aryl group, a heterocyclic group, or a group represented by the general formula (2); Is shown. R ₅ represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, or a heterocyclic group. ) And / or a p-amino unsaturated ketone compound represented by the following general formula (3): [In the formula, m and n are each 0 or 1, and R ₆ and R ₇ are a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, or CH ₂ COOR ₁₁ (where R ₁₁ is a hydrogen atom or 1 carbon atom) To 5 alkyl groups, alkali metals, ammonium, amines), or C ₂ H ₄ CF ₃ , C ₂ H ₄ I, C ₂ H
₄ Br, C ₂ H ₄ Cl, C ₂ H ₄ F, C ₂ H ₄ CN, C ₂ H ₄ N
O ₂ . R ₈ has 1 to 1 carbon atoms capable of forming a ring together with a carbonyl group by bonding to a methylidine group or R ₉ .
R ₉ is a carbon atom, a substituted or unsubstituted phenyl group, or a group which forms an indanone or tetralone with R ₈ and a carbonyl group, a group represented by the general formula (4), (However, R ₁₂ and R ₁₃ are each a hydrogen atom or a group having 1 to 5 carbon atoms.
Or CH ₂ COOR ₁₄ (where R ₁₄ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, an alkali metal, ammonium, an amine), or C ₂ H ₄ C
F ₃ , C ₂ H ₄ I, C ₂ H ₄ Br, C ₂ H ₄ Cl, C ₂ H ₄ F,
C ₂ H ₄ CN and C ₂ H ₄ NO ₂ . )], A quaternary boron salt represented by the following general formula (5) as an auxiliary agent (E): (Wherein, R ₁₅ , R ₁₆ , R ₁₇ and R ₁₈ each independently represent an alkyl group, an aryl group, an allyl group, an alkoxyl group,
An alkenyl group, an alkynyl group, a silyl group, a heterocyclic group, a halogen atom, and Z ⁺ represents a quaternary ammonium cation;
It represents a quaternary pyridinium cation, a quaternary quinolinium cation, a phosphonium cation, a sulfonium cation, an oxosulfonium cation, an iodonium cation or a metal cation. A) a transparent hologram recording material comprising: 2. An aromatic onium salt (C) that generates a radical species that activates radical polymerization and a Bronsted acid or Lewis acid that activates cationic polymerization when exposed to actinic radiation is a diaryliodonium salt. The transparent hologram recording material according to claim 1, wherein: