JPH0659611A - Hologram and method of forming the same - Google Patents

Abstract

(57) [Summary] [Objective] To obtain a hologram having excellent transparency and a method for forming the hologram. A hologram obtained by forming an interference pattern in a record carrier comprising poly-N-vinylcarbazole or a derivative thereof, a bromine-containing monomer, a photopolymerization initiator, and a sensitizing dye. This hologram is prepared by exposing the record carrier to an interference pattern and then immersing the record carrier in a solvent containing acetone, which does not dissolve the binder polymer and can elute the unpolymerized monomer, or without immersing the binder in the solvent. It is formed by immersing in a mixed solvent of a solvent that does not dissolve the polymer and contains acetone capable of eluting the unpolymerized monomer, and a solvent having a boiling point higher than that of the solvent and not eluting the unpolymerized monomer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a volume phase hologram and a method for forming the same.

[0002]

2. Description of the Related Art As a conventional volume phase hologram,
It is generally known that a bleached silver salt or dichromated gelatin is used as a recording medium. However, these have problems in terms of cost, moisture resistance, and complexity of processing. Also,
Various photopolymers have been developed for the purpose of solving this problem. Since poly-N-vinylcarbazole has a high refractive index of about 1.69 and excellent moisture resistance, it is suitable as a binder polymer for hologram photopolymers.

In Japanese Patent Laid-Open No. 2-216180, a hologram is obtained by exposing a recording medium composed of poly-N-vinylcarbazole and a polyfunctional monomer to interference fringes and performing a development process including swelling and shrinking processes. It is disclosed.

[0004]

However, the hologram produced by this method has a problem that white turbidity is apt to occur and it is difficult to obtain a highly transparent hologram. Therefore, an object of the present invention is to provide a hologram having excellent transparency and a method for manufacturing the hologram.

[0005]

The present invention has been made by paying attention to such a conventional problem, and the present inventors have made poly-N-vinylcarbazole or its derivative as a binder polymer a monomer. A compound containing bromine is used, and the development treatment is performed by immersing in a mixed solution of a solvent that does not dissolve the binder polymer and can elute the monomer, and a solvent that has a higher boiling point than this and does not elute the monomer. It is based on the finding that the above problems can be solved by carrying out.

The present invention will be described in detail below. First, the hologram of the present invention is a hologram obtained by forming an interference pattern in a record carrier, in which the record carrier is poly-N-
It is characterized by comprising vinylcarbazole or a derivative thereof, a bromine-containing monomer, a photopolymerization initiator and a sensitizing dye.

Examples of poly-N-vinylcarbazole or its derivative include poly-N-vinylcarbazole, vinylcarbazole-styrene copolymer, vinylcarbazole-vinyl chloride copolymer, vinylcarbazole-methylmethacrylate copolymer, vinyl. Carbazole-vinyl anthracene copolymer, vinylcarbazole-vinylpyridine copolymer, vinylcarbazole-acrylate copolymer, vinylcarbazole-ethylacrylate copolymer, vinylcarbazole-acrylonitrile copolymer, vinylcarbazole-butylacrylate copolymer Coalesce, vinylcarbazole-nitrovinylcarbazole copolymer, nitrated poly-N-vinylcarbazole, polyvinylaminocarbazole, vinylcarbazole-N-
Methylaminovinylcarbazole copolymer, halogen-substituted poly-N-vinylcarbazole, vinylcarbazole-dibromovinylcarbazole copolymer, polyiodovinylcarbazole, polybenzylidenevinylcarbazole, polypropenylcarbazole and the like can be used.

As the bromine-containing monomer, bromine acrylate, bromine methacrylate and the like can be used. For example, the following structural formula

[Chemical 1]

[Chemical 2]

[Chemical 3]

[Chemical 4] (In the above formula, R ₁ and R ₂ are substituted alkyl groups, one of A to H is a bromine atom, the other is a hydrogen atom or a bromine atom, and Y and Z are the following groups.

[Chemical 5]

[Chemical 6] And the like).

Examples of the photopolymerization initiator include benzoyl alkyl ethers, ketals, oximes, esters, benzophenone, thioxanthone derivatives, quinones, aromatic ketones such as thioacridone, and 1,3-di (t-butyldioxycarbonyl). ) Benzene, iodonium salts,
Alkyl or alkylborates such as dianine, rhodamine, safranine, malachite green and methylene blue, iron-arene complexes, bisimidazoles, N-arylglycines, organic peroxides, triazines and the like can be used.

Examples of the sensitizing dyes include aromatic amines such as Michler's ketone, xanthene dyes, thiopyrylium salts, merosinin / quinoline dyes, coumarin dyes, ketocoumarin dyes, acridine orange, benzoflavin, dianine, phthalocyanine, porphine, Rhodamine, safranine, malachite green, methylene green, squarylium dye and the like are used.

Among these, it is particularly preferable to use an organic peroxide or triazine as a photopolymerization initiator and a coumarin-based dye or a squarylium-based dye as a sensitizing dye.
A coumarin dye can be used as a record carrier having a sensitivity to an 488 nm or 514.5 nm argon ion laser, and a squalilium dye can be used as a record carrier having a sensitivity to a 633 nm He-Ne laser.

Specific examples of the organic peroxide include di (t-
Butyl peroxy) isophthalate, di (t-butyl peroxy) terephthalate, di (t-butyl peroxy) phthalate, 3,3 ', 4,4'-tetra- (t-
Butyl peroxycarbonyl) benzophenone.

Specific examples of triazine include TAZ-101, TAZ-102, and TAZ manufactured by Midori Kagaku Co., Ltd.
-103, TAZ-104, TAZ-105, TAZ-
106, TAZ-110, TAZ-111 and TAZ
There is -112 etc.

The coumarin dyes include the following.

[Chemical 7]

[Chemical 8]

[Chemical 9]

[Chemical 10]

[Chemical 11]

[Chemical 12]

The squarylium dyes include the following.

[Chemical 13]

[Chemical 14]

[Chemical 15]

[Chemical 16]

[Chemical 17]

Each composition comprises a binder polymer poly-
100 parts by weight of N-vinylcarbazole or a derivative thereof, 50 to 200 parts by weight of a monomer containing bromine which is a polymerizable compound, 2 to 20 parts by weight of a photopolymerization initiator,
The sensitizing dye is used in a ratio of 0.1 to 2 parts by weight.

Next, a method of forming the record carrier will be described. The above composition is dissolved in a solvent in which each composition is soluble, such as 1,4-dioxane, dichloromethane, chloroform, 1,2-dichloroethane, benzene, chlorobenzene, and tetrahydrofuran. The amount of the solvent used depends on the composition, but is preferably 2 to 20 times the total weight of the composition. The photosensitive solution obtained by dissolving as described above is applied on a support and the solvent is evaporated to form a photosensitive film, which is used as a record carrier. Alternatively, it is made into a film to be a record carrier. As the support, glass, a transparent film of a resin such as polyethylene terephthalate (PET), nylon, or cellulose acetate butyrate (CAB) can be used.

As the coating method, there are Svinner coating, blade coating, roll coating, etc.
Further, for forming a film, there are methods such as casting, biaxial stretching, and calendar roll. Further, when there is a problem in the adhesion between the support and the photosensitive film, a silane coupling agent, a primer or the like may be applied in advance on the surface of the support to improve the adhesion between the support and the photosensitive film. The film thickness of the record carrier is preferably 2 μm to 50 μm.

Next, the hologram exposure process will be described. The light used for exposure is preferably a laser beam or a radiation emitted from a light source such as a mercury lamp. The hologram is exposed by interfering two coherent bundles of radiation in the record carrier. The record carrier that has undergone the exposure process elutes unpolymerized monomers, and thus is immersed in a developing solution containing acetone for development to obtain a hologram.

The developer used is a mixture of a solvent which does not dissolve the binder polymer and can dissolve an unpolymerized monomer, and a solvent which does not dissolve the unpolymerized monomer and has a boiling point higher than that of the solvent. Good. As the solvent that does not dissolve the binder polymer and can dissolve the unpolymerized monomer, acetone, ketones such as methyl isobutyl ketone, cyclohexane and its derivatives, 2-methoxyethanol, 2- (2-ethoxyethoxy) ethanol, Alcohols such as 2- (2-methoxyethoxy) ethanol are available, but it is essential that they always contain acetone. The solvent may be acetone alone or a mixed solvent of acetone and the other solvent described above. However, the presence of acetone can bring about a great effect in obtaining a hologram having high efficiency and excellent transparency. Alkanes such as n-pentane, n-hexane, n-heptane, n-octane and isooctane may be used as the solvent that does not dissolve the unpolymerized monomer.

The composition ratio of the developing solution depends on the constitution of the record carrier and the exposure conditions, but the solvent which can dissolve the unpolymerized monomer is 20 to 80% by weight, and the solvent which does not dissolve it is 20 to 80% by weight.
It is preferable that Further, before carrying out the developing treatment, a process of immersing the record carrier only in a solvent capable of dissolving the unpolymerized monomer can be added to control the wavelength of the hologram diffraction peak.

[0022]

[Operation] Next, the operation will be described. The hologram of the present invention is
High and low refractive index modulation is obtained by forming interference fringes by distributing pores in the matrix of the polymerized component of the binder polymer and the monomer. Therefore, the refractive index difference between the matrix and the holes (refractive index of about 1.0) directly becomes the refractive index modulation of the hologram, and the higher the refractive index of the matrix, the more efficient the hologram can be obtained.

The poly-N-vinylcarbazole or its derivative used as the binder polymer in the present invention has a refractive index of about 1.6 to 1.69, and brom acrylate or brom methacrylate used as a monomer has a refractive index of about 1.55 or more. , Has a value higher than the refractive index of the non-bromine compound, 1.45 to 1.55. Therefore, it is possible to obtain a hologram having a significantly higher efficiency than in the conventional case where a non-bromine compound is used as a monomer. Also,
When a record carrier is taken out from a developing solution composed of a solvent in which the monomer is soluble and a solvent in which the monomer is insoluble, by using a solvent having a low boiling point such as acetone as a component of the developing solution, in which an unpolymerized monomer is soluble, As the solvent capable of dissolving the monomer evaporates, it is replaced with a solvent that does not dissolve the monomer at a suitable rate. Therefore, the size of the pores formed on the record carrier is smaller than that in the case where the solvent is rapidly replaced with a solvent that does not dissolve the monomer, and the obtained hologram has excellent transparency. Further, the solvent such as acetone used for eluting the unpolymerized monomer in the present invention does not dissolve the binder polymer, so that it has an effect of further preventing clouding.

[0024]

The present invention will be described with reference to the following examples and comparative examples. Comparative Example Poly-N-vinylcarbazole (molecular weight 600,000)
(Anan Co., Ltd., trade name Tubicor 210) 0.3
g, 0.15 of isocyanuric acid EO-modified triacrylate (manufactured by Toa Gosei Chemical Industry Co., Ltd., trade name M-315)
g, 3,3 ′, 4,4′-tetra (t-butylperoxidecarbonyl) benzophenone (BTTB) was added to 0.2 g.
024 g and 0.003 g of 3,3'-carbonylbis (7-diethylaminocoumarin) were dissolved in 9 g of 1,4-dioxane to prepare a photosensitive solution. On a 2 mm thick glass plate, 100 μm of the above photosensitive solution was applied, and the temperature was 70 ° C.
After minute drying, a record carrier having a thickness of about 10 μm was obtained. A PVA film was formed on the surface of the record carrier by spin coating.

A hologram was exposed on the obtained record carrier by the hologram exposure optical system shown in FIG. The exposure conditions were a wavelength of 488 nm, an exposure energy of 70 mJ / cm ² , and an incident angle of laser light θ1 = θ2 = 20 °. In FIG. 1, 1 is an argon ion laser device, 2 is a mirror, 3 is a half mirror, 4 is a spatial filter,
5 is a collimation lens, and 6 is a record carrier.

After the exposure, the PVA film on the surface of the record carrier was washed off with water to remove 50% by weight of toluene and 50% by weight of xylene.
It was immersed for 1 minute in the mixed solvent consisting of. The record carrier was taken out, dried at 100 ° C. for 3 minutes, immersed again in a mixed solvent of toluene and xylene for 2 seconds, taken out and immediately immersed in n-heptane for 20 seconds, and then the record carrier was pulled up to obtain a hologram.

The transmission spectrum of the obtained hologram is shown in FIG. The efficiency was 76%, and when visually observed, the hologram was largely opaque and quite opaque.

Example 1 Poly-N-vinylcarbazole (molecular weight 800,000)
(Anan Co., Ltd., trade name Tubicor 210) 0.5
g, EO-modified tribromophenol acrylate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name New Frontier BR3)
1) 0.5 g, BTTB 0.04 g, 3,3′-carbonylbis (7-diethylaminocoumarin) 0.00
25 g was dissolved in 9 g of 1,4-dioxane to prepare a photosensitive solution. A silane coupling agent (trade name: KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.) was spin-coated on a glass plate having a thickness of 2 mm, and the above-mentioned photosensitive solution was applied using a film-forming applicator.
It was applied to a thickness of 00 μm and dried at 70 ° C. for 30 minutes to form a photosensitive film. Further, PVA was spin-coated on the surface of the photosensitive film.

The obtained record carrier was hologram-exposed with the optical system shown in FIG. The exposure conditions were a wavelength of 488 nm, an exposure energy of 40 mJ / cm ² , and θ1 = θ2 = 20 °. The PVA on the surface of the exposed record carrier was removed by washing with water, immersed in a mixed solvent of 30% by weight of acetone and 70% by weight of n-heptane for 4 minutes, pulled up, and then air-dried.

The transmission spectrum of the obtained hologram is shown in FIG. The diffraction efficiency was 94%, the transmittance of the baseline was higher than that of the comparative example, the whitening was small, and the transparency was very excellent.

Example 2 A photosensitive film was formed and PVA was coated in the same manner as in Example 1 except that the amount of 3,3'-carbonylbis (7-diethylaminocoumarin) was changed to 0.005 g. Hologram exposure was performed with the optical system shown in FIG. The exposure conditions are
The wavelength was 488 nm, the irradiation energy was 40 mJ / cm ² immediately before the glass block was incident, and the irradiation was performed at θg = 40 °. In FIG. 3, 7 is a refractive index matching liquid, and 8 is a glass block. After exposure, development processing was performed in the same manner as in Example 1 to obtain a hologram.

The transmission spectrum of the hologram is shown in FIG. The efficiency was 96%, which was extremely high, and the transparency was fairly good.

Example 3 Photosensitive film formation and hologram exposure were carried out in the same manner as in Example 2. The exposed record carrier was washed with water to remove PVA on the surface, and immersed in acetone for 3 minutes. Immediately after taking out the record carrier, 30% by weight of acetone and 70% by weight of n-heptane
It was immersed in the mixed solution of 1 minute for 1 minute, pulled up, and then air dried.

The transmission spectrum of the obtained hologram is shown in FIG. Compared with FIG. 4, the peak wavelength was shifted to the long wavelength side, and it was possible to control the peak wavelength by changing the post-treatment conditions from Example 2. The diffraction efficiency was 91%, and a hologram having excellent transparency was obtained.

In the above Examples 2 and 3, it was shown that the diffraction peak wavelength can be controlled by changing the development processing conditions.

Example 4 0.5 g of Tubicor 210 (molecular weight 800,000), 0.5 g of EO-modified tribromophenol methacrylate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name New Frontier BR31M), 2, 4, 6 -Tris (trichloromethyl)-
0.035 g of s-triazine (TCT), [Chemical formula 17]
0.0025 g of the squalilium dye (SQD) (NK-2990, manufactured by Japan Sensitive Dye Co., Ltd.) was dissolved in 10 g of dichloromethane to prepare a photosensitive solution.

A photosensitive film was formed in the same manner as in Example 1, and hologram exposure was performed using the optical system shown in FIG. Exposure wavelength 633 nm, exposure energy 50 mJ / cm ² , θ
3 = 10 °. After the exposure, the record carrier was washed with water to remove the PVA film on the surface, and the development treatment was carried out in the same manner as in Example 1. In FIG. 6, 9 is a He-Ne laser device and 10 is a plane mirror.

The transmission spectrum of the obtained hologram is shown in FIG. The efficiency was 90%, and a hologram having excellent transparency could be obtained.

Example 5 A photosensitive film was formed in the same manner as in Example 4 except that the SQD was adjusted to 0.0015 g to prepare a record carrier. However, a PET film having a film thickness of 50 μm was used as a support for forming the film. Holographic exposure was performed on the record carrier by the optical system of FIG. The conditions were an exposure wavelength of 633 nm, an exposure energy of 400 mJ / cm ² , and θg = 20 °. After exposure,
The PVA film on the surface was removed by washing with water, and 3% was added to a mixed solution of 60 wt% acetone and 40 wt% 2-methoxyethanol.
Soaked for a minute. Remove the record carrier and immediately use acetone 30
After dipping in a mixed solution of 70 wt% of n-heptane for 1 minute by weight, it was pulled up and air dried.

The transmission spectrum of the obtained hologram is shown in FIG. A highly transparent hologram having a diffraction efficiency of 91% was obtained.

[0041]

As described above, according to the present invention, in a hologram obtained by forming an interference pattern in a record carrier, the structure of the record carrier is poly-N-vinylcarbazole or a binder polymer thereof. Derivatives, polymerizable compounds such as acrylates and methacrylates containing bromine as a monomer, and further as a photopolymerization initiator and a sensitizing dye, in the method of forming a hologram, after the hologram exposure, the record carrier, without dissolving the binder polymer, And a solvent containing acetone that does not dissolve the binder polymer and that can dissolve the unpolymerized component of the monomer, by immersing or not immersing the unpolymerized monomer in a solvent containing acetone that can be eluted, Immerse in a mixed solvent with a solvent that has a high boiling point and does not dissolve the unpolymerized components of the monomer. Due to so as to form a hologram with a diffraction efficiency is extremely high and it was possible to obtain very good hologram transparency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a hologram exposure optical system used in Example 1 and a comparative example.

2 is a transmission spectrum diagram of the hologram obtained in Example 1. FIG.

FIG. 3 is an explanatory diagram of a hologram exposure optical system used in Examples 2 and 3.

4 is a transmission spectrum diagram of the hologram obtained in Example 2. FIG.

5 is a transmission spectrum diagram of the hologram obtained in Example 3. FIG.

FIG. 6 is an explanatory diagram of a hologram exposure optical system used in Example 4.

7 is a transmission spectrum diagram of the hologram obtained in Example 4. FIG.

FIG. 8 is an explanatory diagram of a hologram exposure optical system used in Example 5.

9 is a transmission spectrum diagram of the hologram obtained in Example 5. FIG.

FIG. 10 is a transmission spectrum diagram of a conventional hologram obtained in a comparative example.

[Explanation of symbols]

 1 Argon Ion Laser Device 2 Mirror 3 Half Mirror 4 Spatial Filter 5 Collimation Lens 6 Record Carrier 7 Refractive Index Matching Liquid 8 Glass Block 9 He-Ne Laser Device 10 Planar Mirror

Claims (6)

[Claims] 1. A hologram obtained by forming an interference pattern in a record carrier, wherein the record carrier is poly-N-
A hologram comprising vinylcarbazole or a derivative thereof, a bromine-containing monomer, a photopolymerization initiator, and a sensitizing dye. 2. The hologram according to claim 1, wherein the bromine-containing monomer is brom acrylate or brom methacrylate. 3. The hologram according to claim 3, wherein the photopolymerization initiator is an organic peroxide or triazine, and the sensitizing dye is a coumarin dye. 4. The hologram according to claim 1, wherein the photopolymerization initiator is an organic peroxide or triazine, and the sensitizing dye is a squarylium dye. 5. A solvent containing acetone, which does not dissolve a binder polymer and can elute unpolymerized monomer after exposing an interference pattern in a record carrier, and an unpolymerized monomer having a higher boiling point than this solvent. 2. The hologram forming method according to claim 1, wherein the hologram is formed by immersing the record carrier in a mixed solvent with a solvent that does not elute. 6. After exposing the interference pattern in the record carrier, the record carrier is immersed in a solvent containing acetone in which the binder polymer is not dissolved and unpolymerized monomers can be eluted, and then the binder polymer is dissolved. Characterized in that a hologram is formed by further immersing in a mixed solvent of a solvent containing acetone that does not elute unpolymerized monomer and a solvent that has a higher boiling point than this solvent and does not elute unpolymerized monomer. The method for forming a hologram according to claim 1.