JP2001260219A - Producing method for light diffusion plate, and the light diffusion plate obtained thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide both a producing method for a light diffusion plate, in which a plurality of diffusion reflection plates with reflection characteristics are efficiently and easily produced from a kind of transfer original mold according to use of a reflection type LCD from a reflection plate with intensive specular properties to a diffusion plate with intensive diffusion properties, and the light diffusion plate. SOLUTION: The producing method for the light diffusion plate contains a process forming the thin film layer of a photo-setting resin composition on the base material, a process pressing an original mold, in which an uneven shape face is formed, on the thin film layer and a process making the uneven shape of the thin film layer of an exposure part to a step of 5-95% of the uneven shape of the original mold by controlling exposing amount onto the thin film layer and performing exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a light diffusing plate used for a reflection type liquid crystal display device which does not require a backlight or a solar cell which requires a high efficiency. And a reflection type liquid crystal display incorporating the light diffusion plate.

[0002]

2. Description of the Related Art Liquid crystal displays (hereinafter abbreviated as LCDs)
Utilizing features such as thinness, small size, and low power consumption, is currently used for display units such as watches, calculators, TVs, and personal computers. In recent years, color LCDs have been developed and OA / AV
It has begun to be used in a variety of applications, mainly for equipment, such as navigation systems, viewfinders, personal computers, and monitors for mobile phones. The market is expected to expand rapidly in the future. In particular, reflective LCDs that perform display by reflecting light incident from the outside are attracting attention as portable terminal equipment because they do not require a backlight, consume less power, and can be made thinner and lighter. ing.

Conventionally, a twisted nematic system and a super twisted nematic system have been adopted for a reflection type LCD, but in these systems, a half of the incident light is not used for display by a linear polarizer, and the display becomes dark. turn into. Therefore, the number of polarizers was reduced to one, and a method combined with a retardation plate or a phase transition type guest
A host display mode has been proposed.

In order to obtain a bright display by efficiently using external light in a reflective LCD, it is necessary to further increase the intensity of light scattered in a direction perpendicular to the display screen with respect to incident light from all angles. There is. Therefore, it is necessary to control the reflection film on the reflection plate so as to obtain appropriate reflection characteristics. For this reason, metal with high reflectivity,
For example, in order to use aluminum or silver, or to improve the reflectance of the metal surface, an attempt has been made to laminate an enhanced reflection film on the metal. Further, a method using a so-called photolithography method in which a photosensitive resin is applied to a substrate, patterned using a photomask to form irregularities, and a metal thin film is formed to form a reflector (Japanese Patent Application Laid-Open No. 4-243226). Proposed. At this time, an attempt has been made to improve the reflectance in a predetermined limited angle range centered on the specular reflection direction by controlling the inclination angle of the unevenness to a predetermined angle or less.

[0005]

The size of the display area of the reflective liquid crystal cell differs depending on the purpose of use. For example, a liquid crystal cell used for a mobile phone or the like has a size of several inches or less. On the other hand, a notebook PC or the like generally has a size of 10 inches or more. In these liquid crystal cells,
Each has the required characteristics. However, in a reflection type liquid crystal cell mainly using external light, there is a trade-off between possible brightness and a viewing angle. In a liquid crystal cell having a narrow display area, a difference in viewing angle between a display area corner and a display area corner opposite to a line is small. Therefore, reflected light obtained from external light can be efficiently returned in the viewing direction. However, a liquid crystal cell having a wide display area is required to have a wide viewing angle because the display area corner and the display area corner opposite to the line are separated. Therefore, it is necessary to disperse and reflect light obtained from external light at a wide viewing angle.

That is, the diffuse reflection by the diffuse reflector is
The required reflection characteristics differ depending on the method of using the liquid crystal cell and particularly on the size of the display area. The required reflection characteristics vary from a highly specular reflecting plate to a highly diffusing diffusing plate. Therefore, when manufacturing a diffuse reflection plate by the transfer method, it is necessary to prepare a diffusion reflection plate for each liquid crystal cell depending on the use method of the liquid crystal cell, particularly the size of the display area, and the like. The transfer prototypes for the reflectors had to be prepared and manufactured by the number of liquid crystal cell types. The present invention relates to a reflection type LC having good reflection characteristics.
The present invention provides a light diffusion plate used for a diffuse reflection plate for D and the like, and according to the present invention, a reflection type LC from a single transfer prototype, a reflection plate having a strong mirror surface to a diffusion plate having a strong diffusion property.
It is possible to efficiently and easily manufacture a diffuse reflection plate having a plurality of reflection characteristics according to the method of use of D or the like.

[0007]

According to a method of manufacturing a light diffusing plate of the present invention, a step of forming a thin film layer of a photocurable resin composition on a substrate and an uneven surface capable of diffusing light are formed. The step of pressing the prototype against the thin film layer and the exposure while controlling the amount of exposure to the thin film layer to reduce the unevenness of the thin film layer in the exposed portion to a step of 5% or more and 95% or less of the unevenness of the prototype. This is a method for manufacturing a light diffusing plate including a step of performing the following. In this manufacturing method, a step of heat-treating the substrate may be added when the adjustment of the level difference can be well reproduced after exposure of the thin film layer, or when the softening temperature of the thin film layer is higher than room temperature.

In the method for producing a light diffusing plate of the present invention, the light-curable resin composition flows on the uneven surface of the temporary support on which the uneven surface capable of diffusing light is formed at a softening temperature or higher. Forming a thin film layer to be flattened, bonding a surface of the thin film layer that is not laminated to the temporary support to the substrate, and controlling the amount of exposure to the thin film layer to perform exposure, thereby controlling the amount of exposure. A method for manufacturing a light diffusing plate, comprising a step of making the unevenness of the thin film layer a step of 5% or more and 95% or less of the unevenness of the temporary support. In this manufacturing method, a step of heat-treating the substrate may be added when the adjustment of the level difference can be well reproduced after exposure of the thin film layer, or when the softening temperature of the thin film layer is higher than room temperature.

According to the method for producing a light diffuser of the present invention, it is possible to produce from a single transfer prototype, a reflective plate having a strong specularity to a diffuser having a strong diffusivity. Accordingly, a diffuse reflection plate having a plurality of reflection characteristics can be efficiently and easily manufactured. Therefore, by manufacturing a diffuse reflection plate used for a reflection type liquid crystal display or the like by the method of the present invention, a light diffusion plate having a plurality of reflection characteristics (light diffusion reflection plate) according to a method of using the reflection type LCD or the like. Can be manufactured efficiently and easily, and the visibility of individual LCDs can be increased.

[0010]

According to the method for manufacturing a light diffusion plate (diffuse reflection plate) of the present invention which can be used for a reflection type LCD or the like, a thin film layer is formed on a surface of a substrate on which irregularities are to be formed.
The process of pressing the prototype that has been processed into a state where the surface has a large number of fine irregularities against the thin film layer, and the step of exposing with an insufficient amount of exposure to maintain the irregularities reduce the unevenness to a low level. The process is simpler and less costly than the method of patterning by photolithography, and has a large number of fine irregularities in a desired portion. A light diffusion plate (light diffusion reflection plate) with a plurality of reflection characteristics can be manufactured up to a diffusion plate having a strong reflection characteristic. After the exposure of the thin film layer, if the adjustment of the step is measured with good reproducibility, or if the softening temperature of the thin film layer is equal to or higher than room temperature, a step of flattening the unevenness by heating may be added as necessary. . If a reflective film such as a metal thin film is further formed thereon, a desired light diffusing plate can be obtained.

A step of laminating a thin film layer on a temporary support processed to have a large number of fine irregularities on the surface to form a transfer film; a step of transferring the thin film layer to the irregularity forming surface of the substrate; The step of lowering the step of the unevenness by the step of exposing with an exposure amount that is insufficient to maintain the unevenness makes the process simpler and less expensive than the method of patterning by photolithography, so that a large number of minute It is possible to manufacture a light diffusion plate having a plurality of reflection characteristics from a transfer prototype, which has a rough surface and is a temporary support, to a reflection plate having a strong mirror surface, and a diffusion plate having a strong diffusion property. After the exposure of the thin film layer, if the adjustment of the step is measured with good reproducibility, or if the softening temperature of the thin film layer is equal to or higher than room temperature, a step of flattening the unevenness by heating may be added as necessary. . If a reflective film such as a metal thin film is further formed thereon, a desired light diffusing plate can be obtained.

For example, a temporary support having an uneven surface capable of diffusing light formed on the surface of a film or the like can be obtained by pressing a transfer master having an uneven surface capable of diffusing light on the surface against a film. Manufactured products can also be used. Also, a base film is provided with a deformable undercoat layer, a step of pressing a prototype having an uneven surface capable of diffusing light on this layer, and a step of curing the undercoat layer formed as a temporary support. May be used. A base film having a surface subjected to sandblasting can also be used as a temporary support.

An example of a method of manufacturing a prototype or a temporary support having a concave-convex surface capable of diffusing light is disclosed in the document “Optical Disks, Optronics, published in 1990”. That is, after applying a photoresist on a glass plate, exposing and developing using a photomask having a predetermined mask pattern, or after laser cutting, silver or nickel is formed on the pattern forming surface by a vacuum evaporation method, a sputtering method, or the like. A father model can be manufactured by a process of forming a film (conductivity treatment), laminating nickel by electroforming, and separating from a glass plate. The father prototype is subjected to a peeling treatment, nickel electroforming is performed again, and the mother prototype is peeled off from the father prototype to form a mother prototype, and a large number of fine irregularities can be formed using the mother prototype.

A prototype or a temporary support having an irregular surface capable of diffusing light is capable of diffusing light over the entire surface of a substrate, such as a sheet, a flat plate, a roll, or a part of a curved surface, or a necessary portion. It is possible to use a material having a surface having irregularities that can be formed thereon, and it may be used by sticking it to a pressing device or sandwiching it between the surface on which unevenness is formed and the pressing device. Heat, light, or the like may be given in the pressing step.

As the shape of the thin film layer after curing, the difference in height between the concave portion and the convex portion is 0.1 to 15 μm,
μm, the pitch of the projections is 0.7 μm or more, 150 μm or less, whichever is the smaller of the pixel pitch, and 2 μm or less.
It is preferable that the distance be equal to or larger than m, equal to or smaller than 150 μm or the smaller of the pixel pitch. FIG. 5 shows an apparatus for measuring the reflection characteristics of the light diffusion plate of the present invention. Assuming that the angle between the reflected light beam 21 and the incident light beam 22 is θ, if the luminance observed in the normal direction of the light diffusion plate, that is, the reflection intensity is increased within the required θ range, a light diffusion plate having excellent reflection characteristics can be obtained. can get. In addition, the surface shape of the unevenness is not particularly limited, but not only a composite plane but also a concave curved surface or a convex curved surface, a curved surface of an uneven composite,
Further, it is preferable that the surface is a concave curved surface or a convex curved surface approximating a spherical surface or a parabolic surface, or a curved surface having a complex unevenness. This is because by making the surface curved, diffuse reflection light from a wider range of light source positions can be expected.

In the present invention, the base film used for forming the thin film layer, the temporary support having the uneven surface formed thereon, etc., is chemically and thermally stable and can be formed into a sheet or plate. Can be. Specifically, polyethylene, polyolefins such as polypropylene, polyvinyl chloride, polyvinyl halides such as polyvinylidene chloride,
Examples thereof include cellulose derivatives such as cellulose acetate, nitrocellulose, and cellophane, polyamide, polystyrene, polycarbonate, polyimide, polyester, and metals such as aluminum and copper. Among them, particularly preferred is biaxially stretched polyethylene terephthalate having excellent dimensional stability.

As the thin film layer, a resin composition which can be applied on a support and wound up into a film is used. If necessary, dyes, organic pigments, inorganic pigments, powders, and composites thereof may be used alone or in combination. A photocurable resin composition is used for the thin film layer. The softening temperature of the thin film layer is not particularly limited, but is desirably 200 ° C. or lower. In order to obtain fluidity by heating, a molecular weight of 10
A low melting point substance of 000 or less can be blended.

It is preferable to use a thin film layer having good adhesion to the substrate and good releasability from the base film. For example, as the organic polymer contained in the photocurable resin composition, acrylic resins, polyethylene, polyolefins such as polypropylene, polyvinyl chloride, polyvinyl halides such as polyvinylidene chloride, cellulose acetate, nitrocellulose, cellophane, etc. Cellulose derivative, polyamide, polystyrene, polycarbonate, polyester and the like can be used. When used in a TFT liquid crystal display device, a photosensitive resin that can be developed with an alkali or the like can be used so that a thin film layer in that portion can be removed in order to form a contact hole with a TFT formed in a substrate. Further, in order to improve heat resistance, solvent resistance and shape stability, a resin composition curable by heat can be used. Further, by adding a coupling agent and an adhesion-imparting agent, the adhesion to the substrate can be improved. For the purpose of improving the adhesion, an adhesion imparting agent can be applied to the adhesion surface of the substrate or the thin film layer.

It is preferable to add a low melting point substance having a molecular weight of 10,000 or less in order to obtain fluidity by heating the thin film layer. For example, "Plastics compounding agent" (Akinori Endo, Makoto Sudo, published by Taiseisha, November 1996) ), Or a monomer having at least one ethylenic double bond in the molecule. The amount of this component used is 1% of the total solid content in the photosensitive resin composition.
It is preferable to set it to 70% by weight.

Examples of such compounds include trimethylolpropane triacrylate, trimethylolpropane diacrylate, triethylene glycol diacrylate, diethylene glycol diacrylate, tetraethylene glycol diacrylate, hexamethylene glycol diacrylate, neopentyl glycol diacrylate, Furfuryl acrylate, tetramethylol methane tetraacrylate, resorcinol diacrylate, p, p'-dihydroxydiphenyl diacrylate, spiro glycol diacrylate, cyclohexane dimethylol diacrylate, bisphenol A diacrylate, polypropylene glycol diacrylate,
Pentaerythritol tetraacrylate, ethylene glycolated pentaerythritol tetraacrylate,
Polyfunctional monomers such as dipentaerythritol hexaacrylate, compounds having the same structure using the above acrylate as methacrylate, methylenebisacrylamide, and urethane diacrylate. Also, ECH
Modified phthalic acid diacrylate, tris (acryloxyethyl) isocyanurate, tris (methacryloxyethyl) isocyanurate, tris (2-hydroxyethyl) isocyanurate, polyethylene glycol dimethacrylate, tribromophenyl acrylate, EO modified tribromophenol acrylate And monomers and oligomers having a solid or viscosity of 100,000 cps or more at 25 ° C., such as EO-modified tetrabromobisphenol dimethacrylate. In addition, "Light Sensitive Materials List Book" (edited by Photopolymer Society, published by Bunshin Publishing,
(Issued on March 31, 1996).

Further, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, alkyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, mono (2-methacryloyloxyethyl) acid phosphate, dimethyl methacrylate Monofunctional monomers such as quaternary aminoethyl methacrylate are exemplified.
These components can be used alone or in combination of two or more.

As the photoinitiator of the photocurable resin composition,
For example, benzophenone, N, N'-tetraethyl-
4,4'-diaminobenzophenone, 4-methoxy-
4'-dimethylaminobenzophenone, benzyl, 2,
2-diethoxyacetophenone, benzoin, benzoin methyl ether, benzoin isobutyl ether, benzyldimethyl ketal, α-hydroxyisobutylphenone, thioxanthone, 2-chlorothioxanthone,
1-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propane, t-butylanthraquinone,
-Chloroanthraquinone, 2,3-dichloroanthraquinone, 3-chloro-2-methylanthraquinone, 2-ethylanthraquinone, 1,4-naphthoquinone, 9,10
-Phenanthraquinone, 1,2-benzoanthraquinone-1,4-dimethylanthraquinone, 2-phenylanthraquinone, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer and the like. These photoinitiators are used alone or in combination of two or more. The amount of this component to be used is preferably 0.01 to 25% by weight, more preferably 1 to 20% by weight, based on the total solid content in the photosensitive composition of the present invention.

The undercoat layer used in the present invention is preferably harder than the thin film layer after the formation of the irregularities. For example, polyolefins such as polyethylene and polypropylene, ethylene and vinyl acetate, ethylene and acrylate, ethylene copolymers such as ethylene and vinyl alcohol, polyvinyl chloride, copolymers of vinyl chloride and vinyl acetate, vinyl chloride and vinyl alcohol Copolymers, polyvinylidene chloride, polystyrene, styrene copolymers such as styrene and (meth) acrylate, polyvinyl toluene, vinyl toluene copolymers such as vinyl toluene and (meth) acrylate, poly ( Use of at least one or more organic polymers selected from (meth) acrylates, copolymers of (meth) acrylates such as butyl (meth) acrylate and vinyl acetate, synthetic rubber, cellulose derivatives, and the like. be able to. A photoinitiator, a monomer having an ethylenic double bond, or the like can be added, if necessary, for curing after forming the unevenness. Further, the photosensitive type is shown by using a negative type material, but may be a positive type.

The coating method of the thin film layer and the undercoat layer of the present invention includes roll coater coating, spin coater coating, spray coating, dip coater coating, curtain flow coater coating, wire bar coater coating, gravure coater coating, air knife coater coating and the like. No. The thin film layer or the undercoat layer composition is applied on a temporary support or the like by the above method.

The material for the reflection film may be appropriately selected according to the wavelength region to be reflected.
In the display device, the visible light wavelength range from 300 nm to 8 nm
A metal having a high reflectance at 00 nm, such as aluminum, gold, or silver, is formed by a vacuum evaporation method, a sputtering method, or the like. Further, a reflection increasing film (Optical Overview 2, Junpei Tsujiuchi, Asakura Shoten, issued in 1976) may be laminated by the above method. The thickness of the reflection film is preferably from 0.01 to 50 μm. For example, in a transflective LCD display device, the thickness of the reflective film is preferably 0.001 to 50 μm. The reflection film may be formed in a pattern only by a photolithography method, a mask evaporation method, or the like at a necessary portion.

As the cover film used in the present invention,
Desirably, it is chemically and thermally stable and easy to peel off from the thin film layer. Specifically, a thin sheet made of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl alcohol or the like and having high surface smoothness is preferable. The surface may be subjected to a release treatment to impart releasability.

As a method of laminating a thin film layer on a temporary support (base film or base film provided with an undercoat layer) to a substrate, there is a method in which a cover film is peeled off and heat-pressed on the substrate. When further adhesiveness is required, a method of cleaning the substrate with a necessary chemical solution, applying an adhesion-imparting agent to the substrate, or irradiating the substrate with ultraviolet rays or the like may be used. The apparatus for laminating the transfer film of the present invention is a roll laminator in which the substrate is sandwiched between a rubber roll capable of being heated and pressurized and a base film, and the roll is rotated to feed the substrate while pressing the thin film layer against the substrate. It is preferable to use The thickness of the thin film layer formed on the substrate surface in this manner is 0.1 to 5
A range of 0 μm is preferred. At this time, when the thickness of the thin film layer is thicker than the maximum height difference of the uneven shape, the uneven shape is easily reproduced. If the film thicknesses are equal or thin, the protruding portions of the prototype break through the thin film layer, and unnecessary flat portions are generated, making it difficult to efficiently obtain diffuse reflection.

In order to maintain a shape capable of diffusing light,
The thin film layer is exposed through a mask, and the photosensitive portion is semi-cured. The exposure machine applicable to the present invention includes a carbon arc lamp, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp and the like. The exposure is performed before or after the temporary support is peeled off.

After the exposure, in order to reduce the level difference, it is left indoors for a predetermined time. Alternatively, heating is performed in a hot air heating furnace, an infrared heating furnace, a hot plate, or the like. Further, in order to reduce the step more efficiently, a roll-shaped or plate-shaped press device capable of heating and pressing can be used. It is preferable to use a roll laminator that rotates the roll and feeds the substrate while pressing the roll directly or via a smooth sheet on the substrate.

In the above description, the reflection type LCD device has been described. However, the light diffusion plate of the present invention can be used for a device which needs to diffuse and reflect an external light beam. For example, there is a diffuse reflector for improving the efficiency of a solar cell.

[0031]

The present invention will be described in detail with reference to the following examples. (Example 1) As shown in FIG. 1, a thin film layer forming solution described below was spin-coated on a glass substrate 1 and then dried to form a 3 μm thin film layer 2. Next, a polyethylene terephthalate film sandblasted on the surface (manufactured by Teijin Limited, 50 μm thick, the difference between the height of the concave portion and the convex portion is 0.8 μm,
Using a laminator (roll laminator HLM1500, trade name of Hitachi Chemical Technoplant Co., Ltd.), the substrate temperature is set to 100 ° C., the roll temperature is set to 100 ° C., and the roll pressure is set to 0. 6M
Lamination was performed at Pa (6 kg / cm2) at a speed of 0.5 m / min to obtain a substrate on which a glass substrate, a thin film layer, and a polyethylene terephthalate film (PET film) were laminated. When the PET film was peeled off from this substrate, the sandblasted irregularities were transferred onto the thin film layer,
The uneven shape was excellent in light diffusivity. A light beam (high pressure mercury lamp), which cures a thin film layer on a substrate, is applied to a parallel light exposure machine MAP.
1200L (Dai Nippon Screen Printing Co., Ltd. product name)
Exposure was performed using 70 mJ / cm ² . This substrate is 240
℃, 20 minutes oven (clean oven CSO-40)
2. Heating was carried out under the trade name of Kusumoto Kasei Co., Ltd.), and when the film was cooled to room temperature, the light diffusion property of the exposed portion was lower than that of a sandblasted PET film. The average height difference of the unevenness of the PET film was 1.2 μm, and the average height difference of the unevenness of the thin film layer was 0.8 μm. An aluminum thin film was laminated thereon so as to have a thickness of 0.1 μm by a sputtering method to form a reflection film 3. The light diffusion plate (diffuse reflection plate) thus obtained was excellent in reflection characteristics and could be used as a reflection type LCD diffuse reflection plate. FIG. 2 shows an example in which the light diffusion plate is used for a single-polarization plate type STN reflection type LCD. (Solution for forming thin film layer): Styrene, methyl methacrylate, ethyl acrylate, acrylic acid,
A glycidyl methacrylate copolymer resin was used (Polymer A). The molecular weight is about 35,000 and the acid value is 110.
Parts are parts by weight (the same applies hereinafter). (Polymer) Polymer A 50 parts (Monomer) Pentaerythritol tetraacrylate 50 parts (Photoinitiator) Irgacure 369 (Chiba Specialty Chemicals) 2.2 parts N, N-tetraethyl-4,4'-diaminobenzophenone 2.2 Parts (solvent) Propylene glycol monomethyl ether 492 parts (polymerization inhibitor) p-methoxyphenol 0.1 part (surfactant) Perfluoroalkyl alkoxylate 0.01 part

Example 2 Using the same thin film layer forming solution as in Example 1, a 50 μm thick sand blasted polyethylene terephthalate was used for the base film 4, and a 6 μm film was formed on this film by a comma coater. The film was coated and dried so as to be thick, a thin film layer 2 was formed, and a polyethylene film was coated as a cover film 5 to obtain a transfer film as shown in FIG. Next, while peeling off the cover film of the transfer film, a laminator (roll laminator HLM15) is used so that the thin film layer contacts the glass substrate.
Substrate temperature 100 ° C., roll temperature 100 ° C., roll pressure 0.6 MPa (6 kg / cm ² ), speed 0.5 m /
Then, a substrate on which a glass substrate, a thin film layer, and a polyethylene terephthalate film (PET film) were laminated was obtained. Exposure machine (large manual exposure machine, MAP
1200, a product name of Dainippon Screen Printing Co., Ltd.), the thin film layer was irradiated with 50 mJ / cm ^{2 of} light, and the PET film was peeled off from the substrate. Then, the sandblasted unevenness was transferred onto the thin film layer. And
The uneven shape was excellent in light diffusivity. 240 substrates
℃, 20 minutes oven (clean oven CSO-40)
2. Heating was carried out under the trade name of Kusumoto Kasei Co., Ltd.), and when the film was cooled to room temperature, the light diffusion property of the exposed portion was lower than that of a sandblasted PET film. The average height difference of the unevenness of the PET film was 1.2 μm, and the average height difference of the unevenness of the thin film layer was 0.8 μm. An aluminum thin film was laminated thereon so as to have a thickness of 0.1 μm by a sputtering method to form a reflection film 3. FIG. 4 shows the incident angle dependence of the reflection intensity (relative intensity to the standard white plate) of the diffuse reflection plate manufactured in Example 2 (when the azimuth (φ) is fixed). The optimum reflection intensity was obtained in the range of the incident angle of −60 ° to 60 °, and a light diffusion plate having excellent reflection characteristics was obtained.

Example 3 Example 2 was the same as Example 2 except that an exposure machine (large manual exposure machine, MAP1200, trade name of Dainippon Screen Printing Co., Ltd.) was irradiated with a light beam which reacts the thin film layer at 40 mJ / cm ^2. A diffuse reflector was manufactured under the same conditions. The average height difference of the unevenness of the thin film layer was 0.2 μm. FIG. 4 shows the incident angle dependence of the reflection intensity (relative intensity with respect to the standard white plate) of the diffuse reflection plate manufactured in Example 3 (when the azimuth angle (φ) is fixed). Incident angle -60
The optimum reflection intensity was obtained in the range of ° to 60 °, and a light diffusion plate having excellent reflection characteristics could be obtained.

[0034]

According to the method of the present invention for producing a diffuse reflection plate for a reflection type liquid crystal display device or the like, a diffusion reflection plate having good reflection characteristics can be efficiently produced, and unevenness of one type of transfer prototype can be reduced. By setting it properly beforehand,
The reflection characteristics of the diffuse reflection plate can be freely controlled, and from the reflection plate having a strong mirror surface to the diffusion plate having a strong diffusion characteristic, it is possible to manufacture a diffusion reflection plate having a plurality of reflection characteristics according to the usage of the reflection type LCD. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a production example of a light diffusion plate of the present invention.

FIG. 2 is a cross-sectional view of a reflective LCD.

FIG. 3 is a cross-sectional view illustrating an example of the transfer film of the present invention.

FIG. 4 is a diagram showing the incident angle dependence of the reflection characteristics of the light diffusion plate of the present invention.

FIG. 5 is an apparatus diagram for measuring reflected light characteristics of the light diffusion plate of the present invention.

[Explanation of symbols]

 1. Glass substrate 2. 2. Thin film layer Reflective film 4. Base film 5. Cover film 6. Undercoat layer 11. Color filter 12. Black matrix 13. Transparent electrode 14. Flattening film 15. Alignment film 16. Liquid crystal layer 17. Spacer 18. Retardation film 19. Polarizing plate 20. Sample 21. Reflected light 22. Incident light ray 23. Luminance meter

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Toshikatsu Shimazaki 48 Wadai, Tsukuba, Ibaraki Prefecture Within Hitachi Chemical Co., Ltd. In-house (72) Inventor Keiko Kizawa 48 Wadai, Tsukuba-shi, Ibaraki F-term in Hitachi Chemical Co., Ltd. AG05 AH73 PA02 PB01 PC05 PG14

Claims (4)

[Claims] 1. A step of forming a thin film layer of a photocurable resin composition on a substrate, a step of pressing a prototype having an uneven surface onto the thin film layer, and controlling the amount of exposure to the thin film layer. A method for manufacturing a light diffusing plate, comprising a step of exposing the thin film layer at the exposed portion to a step of 5% or more and 95% or less of the unevenness of the prototype. 2. A step of forming a thin film layer made of a photocurable resin composition and flowing at a softening temperature or higher and flattened on the uneven surface of the temporary support having the uneven surface formed thereon. Bonding the non-laminated surface of the temporary support to the substrate, and controlling the amount of exposure to the thin film layer to perform exposure so that the unevenness of the thin film layer of the exposed portion is reduced to 5% of the unevenness of the temporary support. A method for manufacturing a light diffusing plate including a step of making a step not less than 95% and not more than 95%. 3. A light diffusion plate obtained by the method for producing a light diffusion plate according to claim 1. 4. A reflection type liquid crystal display using a light diffusion plate obtained by the method for producing a light diffusion plate according to claim 1.