JPH1020748A - Manufacturing method of relief hologram - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an original edition with the low cost, and to make the hologram printing, and the formation of hologram by dry development easy, by exposing a pattern of a holography optical system onto a photosensitive layer on a base, increasing the film thickness of the exposed area of the photosensitive layer by heating, and uniformly exposing the whole face of the photosensitive layer. SOLUTION: A photosensitive layer is formed on a base, a pattern of a holography optical system is exposed to the photosensitive layer. The film thickness of the exposed part of the photosensitive layer is increased by heating, and the whole face of the photosensitive layer is uniformly exposed. The increase of the film thickness of the exposed part of the photosensitive resin layer is performed by heating. On this occasion, a monomer of the exposed area is reacted and polymerized by the exposure, so that the density of the monomer in the exposed part, is lowered. Thereby the monomer is moved from the unexposed area to the exposed area, which increases the volume of the exposed part, and increases the film thickness. The monomer moved from the unexposed part to the exposed part, keeps the unreacted condition, after the film thickness is increased by heating, so that the recording of the hologram is stopped by uniformly exposing the whole surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solid imaging composition and a method for producing a relief hologram having an image area having a thickness different from that of a non-image area after exposure.

[0002]

2. Description of the Related Art Holography is a technique for recording and reproducing both the amplitude and phase of a light wave in the same manner, and the recorded thing is called a hologram. The hologram records the phase of light in the form of interference fringes. Holograms have application fields such as three-dimensional display, industrial measurement, optical elements, memory, and information processing. Holograms include rainbow holograms, multiplex holograms, and Lippmann holograms. Rainbow holograms and multi-rex holograms can record interference fringes in the form of a relief on the surface of a photosensitive material, and are called relief holograms, and can be embossed (mass production by hot pressing) or duplicated by the 2P method. Embossed duplication is a method in which an expensive master hologram is created and then repeatedly hot-pressed into a thermoplastic resin.
The (Photo Polymer) method is a method in which a photopolymer such as a UV curable resin is cured in a state in which it is in close contact with the original plate.

A method for producing a relief hologram is a method in which the light intensity distribution of interference fringes is converted into irregularities on a polymer surface for recording, and a high-resolution photosensitive material whose solubility varies depending on the intensity of laser light is used. . There are novolak resin positive resists, three-component chemically amplified positive resists, photocrosslinking resists, photoradical polymerization resists, and photocation polymerization resists. In each case, the method is used in which the holographic optical system is dissolved in a liquid, developed and fixed by hot light or the like, utilizing the fact that there is a change in solubility due to exposure of the pattern of the holographic optical system. The Lippmann hologram is called a volume hologram, and is a method in which interference fringes are formed in layers in a photosensitive material. Examples include silver halide, hardened dichromated gelatin, ferroelectric crystals, photopolymers, and photochromics.

[0004] A hologram is prepared by the following procedure for a polymer matrix recording film containing a monomer, an initiator and a sensitizing dye developed by Du Pont. A hologram is recorded by exposing to visible laser light at 10 to 100 mJ / cm ² . Full-surface exposure with ultraviolet and visible light (350 to 380 nm, 100 mJ
/ cm ² ) to complete the polymerization of the monomer. The degree of modulation of the refractive index is enhanced by post-baking at 120 ° C. for 1 to 2 hours. These are disclosed in JP-A-2-3081 and JP-A-2-3.
No. 082 discloses a volume hologram utilizing a change in refractive index.

[0005] In the conventional method of manufacturing a relief hologram,
There are novolak resin positive resist, three-component chemically amplified positive resist, photocrosslinking resist, photoradical polymerization resist, photocation polymerization resist, etc., all of which require an exposure and development process. Since the process requires a developing solution, the resist swells, pattern defects are likely to occur, and a step of removing the developing solution after development may be required. Has been sent.

JP-A-2-3081 and JP-A-2-3
The volume type hologram utilizing the change in the refractive index disclosed in Japanese Patent Publication No. 082 meets this expectation. However, since the volume type hologram is used, emboss duplication (mass production by hot pressing) or duplication by the 2P method are used. Can not. Embossed duplication is a method in which an expensive master hologram is created and then repeatedly hot-pressed into a thermoplastic resin.
The “mer” method is a method of curing a photopolymer such as a UV curable resin in a state in which the photopolymer is in close contact with the original plate, but none of them can be used. A method of recording a hologram using a multi-component monomer material is disclosed (Optics Vol. 20, No. 4, April 1991)
Month). A film containing a liquid monomer in a polymer is applied to a glass plate and sandwiched with another glass plate to form a hologram recording dry plate. Since the composition is still fluid when sandwiched, it is preferred that the monomer be polymerized to some extent by pre-exposure by UV exposure to stop the flow. The flow can be stopped even by preheating (130 ° C., 8 minutes).

This method is a hologram making method utilizing the movement of monomers between the exposed part and the unexposed part, and is a volume hologram utilizing a difference in refractive index between the exposed part and the unexposed part. Volume holograms have an unsolvable problem that they cannot be replicated. When the exposure amount increases, the hologram after recording appears cloudy, and the S / N ratio decreases.
This is a phase separation between the polymer and the monomer, an undesirable phenomenon.

[0008]

SUMMARY OF THE INVENTION The invention according to claim 1 provides a method for producing a relief hologram capable of realizing an inexpensive master, easy hologram printing, and easy hologram creation by dry development. is there.

[0009]

The present invention comprises (A) a step of providing a photosensitive layer on a substrate, (B) a step of exposing a pattern of a holographic optical system to the photosensitive layer, and (C) a step of heating the photosensitive layer. And (D) uniformly exposing the entire surface of the photosensitive layer to a method for producing a relief hologram.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a photosensitive layer provided on a substrate can be formed by applying an organic solvent solution of a photosensitive resin composition (described later) to the substrate and drying the solution. In view of the above, it is preferable to use a photosensitive film. The photosensitive film is obtained by applying a photosensitive resin composition on a transparent base film, for example, a film of polyethylene terephthalate or the like, and then drying to form a photosensitive layer. This photosensitive layer is uncured,
Since it is flexible and sticky, it is desirable to further attach a protective film such as a polyethylene film thereon to prevent external damage and adhesion of foreign substances. The photosensitive layer formed on the photosensitive film is bonded to a transparent substrate while peeling off the protective film, and the base film on the surface of the photosensitive layer is usually removed after exposure. However, even after the hologram is completed, the base film can be used as a protective film for the hologram without being peeled off, and can be used as a protective film for the hologram.

The thickness of the transparent base film or protective film is preferably as small as possible because high resolution is required for recording a hologram.
Are suitable for use. Base films include low-density polyethylene, high-density polyethylene, polypropylene,
Polystyrene, poly-4-methylpentene-1, polybutadiene, acrylonitrile copolymer, vinylidene chloride-methyl acrylate copolymer, ethylene vinyl alcohol copolymer, polyvinyl alcohol (PVA), polyamide, polyester (OPET), non-crystalline Polyester (PET), polycarbonate, polytetrafluoroethylene, silicone elastomer, polyvinyl chloride (P
VC) and the like are preferable.

The photosensitive layer is not particularly restricted but includes (a) an ethylenically unsaturated compound, (b) a film-imparting polymer,
(C) The layer is preferably a layer of a photosensitive resin composition containing a photopolymerization initiator, and the thickness of the photosensitive layer is preferably 0.5 to 5 μm. Examples of the substrate in the present invention include a glass plate and a flexible plate such as plastic. These are preferably transparent. The thickness of the substrate is usually 0.5 to 5 mm.

As the ethylenically unsaturated compound (a),
For example, compounds obtained by adding an α, β-unsaturated carboxylic acid to a polyhydric alcohol (trimethylolpropane diacrylate, trimethylolpropane triacrylate, tetramethylolmethane triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate) Acrylate), compounds obtained by adding an α, β-unsaturated carboxylic acid to a glycidyl group-containing compound (trimethylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate, etc.), polyvalent carboxylic acid (anhydride) Esterified product of a compound having a hydroxyl group and an ethylenically unsaturated group (such as β-hydroxyethyl acrylate), an alkyl ester of acrylic acid (methyl acrylate, ethyl acrylate, Butyl acrylate, 2-ethylhexyl acrylate, etc.), urethane diacrylate compound obtained by reacting trimethylhexamethylene diisocyanate with dihydric alcohol and divalent acrylic acid monoester, alkylene oxide of bisphenol A (ethylene oxide, Compounds having a hydroxyl group and an ethylenically unsaturated group (β-
Esterified with hydroxyethyl acrylate (2,2-bis [(4-acryloxypentaethoxy))
Phenyl] propane), γ-chloro-β-hydroxypropyl-β′-acryloyloxyethyl-o-phthalate, and the corresponding methacrylate. These compounds are used alone or in combination of two or more.

From the viewpoints of photosensitivity and developability, the amount of component (a) is preferably 90 to 50 parts by weight based on 100 parts by weight of the total of components (a) and (b).

The polymer (b) for imparting film properties includes:
For example, copolymers of alkyl acrylate or alkyl methacrylate with acrylic acid or methacrylic acid, copolymers of alkyl acrylate or alkyl methacrylate with acrylic acid or methacrylic acid and vinyl monomers copolymerizable therewith. Polymers.

Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and the like. Examples of the alkyl methacrylate include those corresponding to the above-mentioned alkyl acrylate. Examples of the copolymerizable vinyl monomer include, for example,
Dimethylaminoethyl acrylate, tetrahydrofurfuryl acrylate, aminoethyl acrylate, 2,2,2-trifluoroethyl acrylate,
2,2,3,3-tetrafluoropropyl acrylate, methacrylate, acrylamide, methacrylamide diacetone acrylamide, styrene, vinyltoluene and the like corresponding thereto.

(B) Examples of the film-imparting polymer include polyesters using terephthalic acid, isophthalic acid, sebacic acid, etc., copolymers of butadiene and acrylonitrile, cellulose acetate, cellulose acetate butyrate, methyl cellulose, ethyl cellulose. Can also be used in combination. The use of the component (b) improves the coating properties and the film properties of the cured product, and the compounding amount is preferably from 10 to 50 parts by weight based on 100 parts by weight of the total amount of the components (a) and (b). . When the amount is less than 10 parts by weight, the photosensitivity tends to decrease because the amount of the ethylenically unsaturated compound increases, and when it exceeds 50 parts by weight, the photocured product tends to become brittle. The weight-average molecular weight of the component (b) is 10,000 from the viewpoint of the coating properties and film strength.
It is preferably from 0 to 500,000. The weight average molecular weight is a value converted into polystyrene by gel permeation chromatography.

Examples of the photopolymerization initiator (c) include aromatic ketones (benzophenone, N, N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), 4-methoxy-4'-dimethyl) Aminobenzophenone, 4,4'-diethylaminobenzophenone, 2-
Ethyl anthraquinone, phenanthrene quinone, etc.), benzoin ether (benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether, etc.), benzoin (methyl benzoin, ethyl benzoin, etc.), 2,4,5-triarylimidazole dimer, 2- (O-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl)-
4,5-di (m-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2-
(O-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5
-Diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) -5-phenylimidazole dimer,
2- (2,4-dimethoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer, etc., acridine derivative (1,7- Bis (9-acridinyl) heptane and the like are used. These compounds are used alone or in combination of two or more.

The amount of component (c) is 0.1 to 10 parts by weight based on 100 parts by weight of the total of components (a) and (b).
Parts by weight are preferred. When the amount is less than 0.1 part by weight, the photosensitivity tends to be insufficient. When the amount exceeds 10 parts by weight, light absorption on the surface of the composition during exposure increases,
Light curing inside tends to be insufficient.

In the colored photosensitive resin layer, a melamine resin and / or an epoxy resin which thermally reacts with a carboxyl group of a carboxyl group-containing film-imparting polymer in order to enhance heat-curability are added to the component (a) and the component (b). Total amount of ingredients 10
It is preferable to add 1 to 20 parts by weight to 0 parts by weight and heat the mixture. The heating temperature is preferably from 130 to 200 ° C., and the heating time is preferably from 30 to 60 minutes, from the viewpoint of improving the crosslinking density of the colored layer, improving the heat resistance, and the like.

Next, the details of the steps (A) to (D) will be described. (A) Step of Providing Photosensitive Layer on Substrate For example, the photosensitive layer can be provided on the substrate by attaching a photosensitive film to the substrate such that the photosensitive layer is in contact with the substrate. The sticking is performed by using a device that normally rotates two or more rubber rolls called a laminator. Lay the substrate and film together and pass between the rubber rolls.
It can be performed by pressing and heating. The sticking is not limited to this method, and the sticking may be performed by stacking the substrate and the photosensitive film and rubbing with the belly of the thumb. There is also a spatula method. Pushing with a rolling pin, rubbing with L steel, and laminating with a bar coater, applicator, etc., are also considered to be effective methods. There are also methods of vacuum laminator and vacuum pressurization.

(B) Step of exposing the pattern of the holographic optical system to the photosensitive layer A normal holographic optical system (for example, a Lieppmann-type hologram forming apparatus, a Denisik-type hologram forming apparatus, etc.) is used. 6 nm light can be used with high sensitivity. In the two-beam optical system, the spatial frequency of interference fringes due to 441.6 nm light is 775 lines / mm when the tilt angle of the two beams is θ = 20 °. The laser light source is He-Ne
(632.8 nm) He-Cd (441.6) Ar ions (514.5 nm, 488.0 nm) and the like. For a semiconductor laser, a hologram can be formed by selecting the sensitivity of the photosensitive layer.

(C) Step of increasing the thickness of the exposed portion of the photosensitive layer by heating The step of increasing the thickness of the exposed portion of the photosensitive resin layer is performed by heating. By the exposure of (B), the monomer in the exposed portion reacts to be polymerized, so that the concentration of the monomer in the exposed portion decreases. For this reason, the monomer moves from the unexposed portion to the exposed portion, so that the volume of the exposed portion increases and the film thickness increases.
Since the rate of increase in the film thickness changes depending on the temperature, it is preferable that the heating be performed at a temperature of room temperature or higher and at a temperature lower than the temperature at which the photosensitive resin layer starts a thermosetting reaction. The increase in the film thickness is caused by the fact that the film thickness of the photosensitive layer is 0.
When the thickness is 5 μm to 10 μm, the thickness is changed from 0.2 μm to 0.6 μm, and tends to be saturated. When the thickness of the photosensitive layer becomes 10 μm or more, and when the thickness increases, no clear increase in the thickness is observed. This is because the monomer enters the void at the photocured portion. The film thickness increases at a low temperature for a long time and at a high temperature for a short time. Heating includes, but is not limited to, hot plate heating, oven heating, ultrasonic heating, infrared heating, electromagnetic induction heating, hot water immersion, friction heat heating, heating in a pressure oven, heating in a vacuum vessel, etc. Not done. Usually, the heating temperature is 25 to 150 ° C, preferably 50 to 120 ° C.
And the heating time is 1 to 60 minutes.

(D) Step of uniformly exposing the entire surface of the photosensitive layer After the film thickness is increased by heating, the monomer moved from the unexposed portion to the exposed portion remains unreacted, so that the entire surface is uniformly exposed. Thus, the recording of the hologram can be stopped. By this step, the hologram is fixed and fixed. Since the development step is performed by heating, there is an advantage that a uniform hologram can be obtained without the occurrence of collapse, breakage, or chipping of the image due to development, as compared with the conventional method.
The steps (B) and (C) can be performed simultaneously or sequentially. An optimum film thickness can be obtained by a combination of the steps (D) and (C). That is, the thickness of the exposed portion can be adjusted.

Since the hologram obtained by the present invention is of a relief type, it can be printed and copied, and mass production is possible. The contents of those steps will be described. In the process, usually, a stamper is prepared from the hologram of the present invention after the production of a duplicate master, and embossed duplication, transfer foil processing, and transfer are performed using the duplicate master to obtain a product.

[Preparation of Stamper] Since the hologram obtained by the present invention has a strong strength itself, it is possible to prepare a metallic stamper as it is and to use it as an original for replication. The stamper is obtained by plating nickel on the relief surface of the original hologram sufficiently thick and then peeling it off. By repeating the same plating from the obtained stamper, a plurality of stampers can be duplicated. [Preparation of duplicate master] A release layer and a hologram layer are coated on a base film in this order to form a duplicate master. The base film is 9 to 2 in terms of heat resistance, strength, dimensional stability, etc.
A 5 μm polyester film is used.

[Emboss Duplication] In the process of embossing a hologram, one cycle consists of heating press → cooling → peeling. In the heating press step, the hologram layer of the duplicate master is pressed into close contact with the stamper, heated to a temperature higher than the glass transition point, softened, and flows into the concave portion of the stamper. In the cooling step, the hologram layer is solidified and a relief shape is formed. There are a flat press and a roll press as a method of emboss duplication. [Transfer foil] The embossed original plate becomes a transfer foil after forming a reflective layer and coating an adhesive layer. [Transfer] The transfer can be performed by stacking the transfer material and the transfer foil and performing an up-down rubber embossing. Apart from this, there is also roll pressing, and both are possible.

When the photosensitive film is attached to the substrate and the pattern of the holographic optical system is exposed and heated, the monomer (a) is initially uniformly distributed in the matrix polymer, but the monomer is polymerized in the exposed portion. As a result, the monomer moves from the surroundings to the exposed portion as the polymer is replaced. Therefore, the monomer density is high in the exposed portion, and low in the non-exposed portion. As a result, the film thickness of the exposed part increases and decreases in the non-exposed part. When the entire surface is uniformly exposed, the monomer that has moved to the exposed portion is polymerized. In addition, the monomer in the non-exposed area also polymerizes. As a result, the monomer no longer moves, and the relief hologram is fixed. In the present invention, development using a developer is unnecessary, and a relief structure can be obtained by complete dry development.

[0029]

The present invention will be described below with reference to examples. Example 1 (1) Production of Coating Solution for Photosensitive Layer 5 parts by weight of melamine resin were added to 200 parts by weight of a solution in which the materials in Table 1 were uniformly dissolved, and each was dissolved and dispersed to obtain a coating solution for a photosensitive layer. Was.

[0030]

[Table 1]

Melamine resin Cymel 300 (trade name of hexamethoxymethyl melamine, manufactured by Mitsui Toatsu Co., Ltd.) Preparation of coating liquid The coating liquid was prepared by mixing each material with ultrasonic waves for 2.5 hours.

(2) Coating of photosensitive film The obtained solution was coated on a 6 μm thick polyethylene terephthalate film (Tetron film M5R manufactured by Teijin Co., Ltd.).
6) It was applied to a uniform thickness using a kiss-touch reverse type coating machine, and dried with a dryer at 100 ° C. for 2 minutes.
A 30 μm-thick polyethylene film was laminated as a protective film to obtain a photosensitive film. The thickness of the photosensitive layer after drying is 1.0 μm, 2.0 μm, 3.0 μm, 5.
It was 0 μm.

(3) Production of Hologram (a) Substrate Heating Step The hologram substrate was heated at 80 ° C. for 10 minutes. (B) Laminating Step While peeling off the protective film of the hologram photosensitive film, a colored photosensitive resin layer was laminated on the hologram base substrate under the following conditions. Roll temperature 60 ° C Roll pressure 1.0kg / cm ² Speed 2.5m / min

(C) Exposure step Using an optical system of an argon laser (488.0 nm), 1
The pattern of the diffraction grating of 000 lines / mm was exposed. The exposure amount was 350 mJ / cm ² . (D) Heating Step After the exposure, heating was performed at 80 ° C. for 15 minutes to increase the thickness of the exposed portion. (E) Overall exposure step Immediately after heating, an ultraviolet irradiator (lamp H5600L /
2. Toshiba Denshi Co., Ltd.) at 3 J / cm ² and then
The hologram was obtained by heating at 50 ° C. for 45 minutes. (F) Peeling Step The polyethylene terephthalate film was peeled at room temperature by an automatic peeling device (a self-made prototype, a device for peeling the polyethylene terephthalate film with a roll to which a double-sided tape was attached).

The steps (a) to (f) of forming the hologram are carried out by changing the thickness of the photosensitive resin layer to 1.0 μm, 2.0 μm,
The measurement was performed for 3.0 μm and 5.0 μm. The following results were obtained.

[0036]

[Table 2]

Comparative Example 1 The same procedure as in Example 1 was carried out except that the heating step was as follows. (D) Heating Step After the exposure, the film was left at room temperature without heating. The steps (a) to (f) of forming the hologram are performed by changing the thickness of the photosensitive resin layer to 1.0 μm, 2.0 μm, 3.0 μm,
This was performed for 5.0 μm. The following results were obtained.

[0038]

[Table 3]

In Comparative Example 1, no heating was performed after the exposure, so that no difference in film thickness appeared. This is because the movement of the monomer was slow and did not increase the film thickness.

Example 2 The procedure of Example 1 was repeated, except that the materials shown in Table 4 below were replaced with the materials shown in Table 1.

[0041]

[Table 4]

Example 3 The same operation as in Example 1 was carried out except that the materials in Table 5 below were replaced with the materials in Table 1, and the same good results as in Example 1 were obtained.

[0043]

[Table 5]

Example 4 The same operation as in Example 1 was carried out except that the materials in Table 6 below were replaced with the materials in Table 1, and the same good results as in Example 1 were obtained.

[0045]

[Table 6]

Example 5 The same operation as in Example 1 was performed except that the materials in Table 7 below were replaced with the materials in Table 1, and the same good results as in Example 1 were obtained.

[0047]

[Table 7]

[0048]

According to the first aspect of the present invention, there is provided a method for producing a relief hologram which can realize the production of an inexpensive master, the ease of hologram printing, and the ease of hologram production by dry development.

Claims (1)

[Claims] (A) providing a photosensitive layer on a substrate,
(B) a step of exposing the pattern of the holographic optical system to the photosensitive layer, (C) a step of increasing the thickness of the exposed portion of the photosensitive layer by heating, and (D) a step of uniformly exposing the entire surface of the photosensitive layer. A method for producing a relief hologram, comprising: