JP2000297110A - Composition for anisotropic light scattering film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compsn. for an anisotropic light scattering film in which a cation polymerizable compd. and a radical polymerizable compd. have difference in their refractivity indices. SOLUTION: This compd. which forms a light scattering film having an injection angle selectivity to light scattering and performs as a transparent film to a light perpendicular to slanting direction and comprises a compd. having cation polymerization character (A), a compd. having radical polymerization character (B), and a light initiator (C) which generates a cation species and a radical species by chemical radiation, and there is a difference between refractivity indices of the compd. having cation polymerization character (A) and the compd. having radical polymerization character (B).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has different scattering properties depending on the incident angle of light (or has incident angle selectivity).
In addition, the present invention relates to a composition for a light diffusion film having anisotropic light scattering characteristics.

[0002]

2. Description of the Related Art In a display device utilizing light, such as a reflection type liquid crystal display device or a transmission type liquid crystal display device, a viewing angle at the time of observation is secured (that is, a brightly displayed image is displayed on the front surface of the display device). For example, a light-diffusing film is disposed on the front of the apparatus for the purpose of showing the display screen with uniform brightness over the entire display screen. As a conventional light scattering film, a resin film whose surface is processed into a mat shape, a resin film containing a diffusing material inside, and the like are used.

[0003] In the case of a conventional resin film processed into a mat shape or a film containing a diffusing material inside, it is difficult in principle to provide a function such as a change in scattering depending on the incident angle of incident light. It does not have such a function.

In the case of a light-scattering film whose surface is processed into a mat shape, the film surface is physically formed with a matte surface such as a sandblaster treatment, or chemically matted by a dissolution treatment with an acidic or alkaline solution. To form Therefore, it is difficult to control the light scattering property, and it is impossible to change the vertical and horizontal scattering properties, so that it is not possible to impart scattering anisotropy.

[0005] In a light-scattering film containing a diffusing material therein, attempts have been made to control the refractive index, size, shape, etc. of the diffusing material in order to control the scattering.
At present, it is technically difficult and not sufficiently practical.

Accordingly, the above-mentioned light-scattering film has no scattering angle dependence and no or little anisotropy of light scattering, so that when used in a display device, unnecessary scattered light is generated. As a result, there is a problem that the brightness and contrast of display are reduced or a displayed image is blurred.

On the other hand, as a proposal relating to a reflection type liquid crystal display device using a scattering plate having anisotropic light scattering, Japanese Patent Application Laid-Open No. Hei 8-2
No. 0180 is known. The scattering plate disclosed in the above publication is a scattering plate having almost no back scattering characteristics and strong forward scattering characteristics, and selectively scatters either the incident light to the liquid crystal display device or the display light emitted from the liquid crystal display device. It has the property to make it.

However, the above publication does not specifically describe the structure of the scattering plate, but only describes "the transparent fine particles hardened with a transparent polymerizable polymer".
In such a scattering plate, as in the case of the "light diffusion film containing a diffusion material therein", even if the scattering characteristics are given anisotropy (forward or backward), the scattering in the vertical and horizontal directions is not possible. It is difficult to control even the characteristics.

As a proposal for a transmission type liquid crystal display device using a hologram as a scattering plate, see Japanese Patent Application Laid-Open No. 9-152.
No. 602 is known. The above proposal scatters display light emitted from a liquid crystal display device having a backlight, and employs a hologram as a scattering plate. Although it is possible to control the horizontal scattering characteristics, it is inevitably accompanied by spectral dispersion (wavelength dispersion), so that the color of the display light changes and is visually perceived as the viewpoint to be observed is moved. Will be.

[0010]

SUMMARY OF THE INVENTION According to the present invention, it is possible to provide anisotropic scattering properties (depending on the forward or backward direction and the incident angle) and to control the scattering properties in the vertical and horizontal scattering ranges. An object of the present invention is to provide a composition for obtaining an anisotropic scatterer that is easy and does not change the color of display light depending on the observation position.

[0111]

According to the anisotropic scattering film obtained from the present invention, a portion having a different refractive index is distributed in an irregular shape and thickness inside the film, so that the light and shade having a high and low refractive index can be obtained. Patterns are formed, and by optimizing the size, shape, and distribution of the portions with different refractive indexes along the vertical and horizontal directions on the film surface and the thickness direction of the film, the scattering characteristics depending on the incident angle In addition to having a change, light scattering in unnecessary directions is eliminated, and light is scattered only in necessary directions (ranges). The present invention provides that a cationic polymerizable compound and a radical polymerizable compound each have a refractive index. And a composition for an anisotropic scattering film characterized by having a difference in

In the composition for an anisotropic light-scattering film according to the first aspect, a portion having a different refractive index is distributed in an irregular shape and thickness, thereby forming a light and shade pattern having a high and low refractive index. The portion having the different refractive index is a light scattering film having a structure that is inclined and distributed in a layered manner with respect to the thickness direction of the film, and the light incident at an angle along the inclination direction of the portion having the different refractive index. In contrast, the composition which forms a light-scattering film having incident angle selectivity in addition to light-scattering function which functions as a mere transparent film with respect to light perpendicular to the tilt direction is (A) cationically polymerizable. And (B) a compound having radical polymerizability, (C) a photoinitiator that generates cationic species and radical species by actinic radiation, and (A) a compound having cationic polymerizability and (B) Characterized in that there is a difference in the refractive index of the compound having a radical polymerizable.

The composition for an anisotropic light-scattering film according to claim 2 further comprises a sensitizing dye (D) for sensitizing a photoinitiator (C) that generates a cationic species and a radical species by the actinic radiation. It is characterized by.

The composition for an anisotropic light-scattering film according to claim 3, wherein the compound (A) having cationic polymerizability has an epoxy equivalent of 400 to 2,200.
Characterized in that it is a type epoxy resin or a brominated bisphenol A type epoxy resin.

In the composition for an anisotropic light-scattering film according to claim 4, the compound (B) having radical polymerizability has a lower refractive index than the compound (A) having cationic polymerizability, At 100 ° C at normal pressure and liquid
It is a compound having at least one ethylenically unsaturated bond as described above.

The composition for an anisotropic light-scattering film according to claim 5, wherein the compound (A) 1 having cationic polymerizability is used.
It is characterized by mixing 20 to 80 parts by weight of the compound (B) having radical polymerizability with respect to 00 parts by weight.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 shows that the portions having different refractive indexes have irregular shapes.
It is explanatory drawing which shows the light-scattering film 1 in which the density pattern which distributed in thickness and the refractive index was high and low (it represents with black and white in the figure) was formed, the left is a top view, and the right is a cross section. FIG.

As can be seen from the plan view, the shape of the portion having a different refractive index is horizontally long. Further, as can be seen from the cross-sectional view, the portions having different refractive indexes have a structure distributed in a layer shape inclined with respect to the thickness direction of the film. In FIG. 1, the distribution of the refractive index is uniform (the color does not change in the inclined direction) in the direction in which the portions having different refractive indexes are inclined in layers.

FIG. 2 is an explanatory view showing a light-scattering film 1 according to another embodiment of the present invention. The left is a plan view and the right is a cross-sectional view. In FIG. 2, the shape of the portion having a different refractive index is vertically elongated, and the distribution of the refractive index is irregular in the direction in which the portion having a different refractive index is inclined in a layered manner (the color changes even in the inclined direction). Is).

First, the optical characteristics of the light-scattering films shown in FIGS. 1 and 2 will be considered in a sectional view. Light scattering occurs for light incident at an angle along the above-mentioned inclination direction in which portions having different refractive indices are distributed in layers (an angle θ from the perpendicular to the film, in the direction of arrow 2 in FIG. 2). Become.

An angle perpendicular to the inclination direction (arrow 3 in the figure)
), It functions as a mere transparent film, and the incident light exits without being scattered.

Next, considering a plan view, when the shape of the portion having a different refractive index is vertically long (or horizontally long), when the light incident on that portion is scattered and emitted, It has anisotropy such that the light scattering characteristics are horizontally long (or vertically long). In FIG. 1, the emitted light is scattered vertically because the shape is horizontal, and in FIG. 2, the emitted light is scattered horizontally because the shape is vertical.

FIG. 3 is a graph showing an example of the incident angle dependency of the light scattering film 1 produced using the composition of the present invention. As shown by the solid line in the figure, the haze value is 80% or more for light in a specific incident angle range (0 to 60 degrees in the figure), and conversely, the incident angle is symmetric (−60 degrees in the figure). The haze value with respect to the light of (from 0 ° to 0 °) is 20% or less, which indicates the scattering angle dependence in the present specification.

Further, as described above, when the shape of the portion having a different refractive index is vertically long (or horizontally long), when the light incident on the portion is scattered and emitted, the light emitted from each portion is emitted. It has anisotropy such that its scattering characteristics are horizontally long (or vertically long). For example, if the shape is horizontally long as shown in FIG. 1, the scattered light emitted from the light scattering film has a distribution such that it becomes a vertically long ellipse as shown in FIG.

Next, the composition for an anisotropic light scattering film of the present invention will be described in detail. As described above, the inside of the anisotropic light-scattering film made of the composition of the present invention forms a light and shade pattern composed of high and low refractive indexes by distributing portions having different refractive indexes in an irregular shape and thickness. Have been.

If the difference in the refractive index is too small, the scattering property deteriorates. On the contrary, if the difference is too large, light scattering occurs regardless of the incident angle of the light. It becomes difficult to have dependencies.

(A) used in the composition of the present invention
A compound having cationic polymerizability is a compound having cationic polymerizability that is polymerized or cross-linked by actinic radiation in the presence of an initiator that generates cations by actinic radiation, such as an epoxy compound, a cyclic ether compound, or a cyclic compound. It comprises one or a mixture of two or more of a lactone compound, a cyclic acetal compound, a cyclic thioether compound, a spiroorthoester compound, a vinyl compound and the like. Among these compounds having cationic polymerizability, compounds having at least one epoxy group in one molecule are preferable, and examples thereof include conventionally known aromatic epoxy resins and alicyclic epoxy resins.

Preferred as the aromatic epoxy resin is a polyglycidyl ether of a polyhydric phenol having at least one aromatic ring or an alkylene oxide adduct thereof, such as bisphenol A or an alkylene oxide adduct thereof and epichlorohydrin. Glycidyl ether and epoxy novolak resin produced by the reaction are exemplified. Bisphenol A, Bisphenol AD, Bisphenol B, Bisphenol A
Epoxy compounds produced by a condensation reaction of various phenol compounds of F, bisphenol S, brominated bisphenol A, novolak, o-cresol novolak, and p-alkylphenol novolak with epichlorohydrin can be mentioned. Since the brominated bisphenol A epoxy compound becomes insoluble in a solvent when the epoxy equivalent is increased, it is effective to use the epoxy compound in a mixed system without using it alone.

Representative examples of alicyclic epoxy resins include hydrogenated glycidyl ethers prepared by the reaction of bisphenol A or an alkylene oxide adduct thereof with epichlorohydrin, particularly hydrogenated bisphenol A, hydrogenated bisphenol AD, Hydrogenated bisphenol B,
Examples include hydrogenated bisphenol AF, hydrogenated bisphenol S, hydrogenated brominated bisphenol A, and the like.

Among the compounds having cationic polymerizability, the molecular weight is from 400, except for epoxy compounds produced by the condensation reaction of various phenol compounds such as volak, o-cresol novolak and p-alkylphenol novolak with epichlorohydrin. 1000 is preferred,
If it is smaller than this, it becomes a liquid, and it cannot be obtained as a film unless a curing treatment by a pretreatment is performed, and uniform coating cannot be performed. If the molecular weight is larger than this range, no characteristics can be obtained.

(B) used in the composition of the present invention
A compound having radical polymerizability is a compound having radical polymerizability that is polymerized or cross-linked by actinic radiation in the presence of an initiator that generates radicals by actinic radiation. It contains at least one or more unsaturated bonds, contains a polyfunctional vinyl monomer in addition to a monofunctional vinyl monomer, and may be a mixture thereof.

Specifically, high-boiling vinyl monomers such as (meth) acrylic acid, itaconic acid, maleic acid, (meth) acrylamide, diacetone acrylamide, 2-hydroxyethyl (meth) acrylate, and aliphatic Hydroxy compounds, such as ethylene glycol,
Diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, neopentyl glycol, 1,3-propanediol, 1,4
-Butanediol, 1,5-pentanediol, 1,6
Di- or poly (meth) acrylates such as -hexanediol, 1,10-decanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol, and mannitol; and the like, but are not limited thereto. The refractive index of (A) the compound having cationic polymerizability used in the present invention and the refractive index of (B) the compound having radical polymerizability need to be different from each other. The so-called haze ratio increases. Generally, it is preferable that the refractive index difference is 0.01 or more, more preferably 0.05 or more.

(C) used in the composition of the present invention
As a photoinitiator system that generates a radical species and a cationic species by actinic radiation, J. Pharm. Photochem. Sc
i. Technol. , 2,283 (1987). Compounds, specifically iron arene complex, trihalogenomethyl-substituted s-triazine, sulfonium salt, diazonium salt, phosphonium salt, selenonium salt,
Arsonium salts, iodonium salts and the like, and examples of iodonium salts include Macromolecule
s, 10 , 1307 (1977). And diphenyliodonium, ditolyliodonium, phenyl (p-anisyl) iodonium, bis (m
-Nitrophenyl) iodonium, bis (p-tert-butylphenyl) iodonium, bis (p-chlorophenyl) iodonium and the like, iodonium chloride, bromide, or borofluoride, hexafluorophosphate salt, hexafluoroarsenate salt, aromatic Group sulfonates and the like.

The sensitizing dye (D) for sensitizing the photoinitiator (C) which generates a cationic species and a radical species by actinic radiation according to the present invention includes cyanine or merocyanine derivatives, coumarin derivatives, chalcone derivatives, xanthene derivatives. Organic dye compounds such as derivatives, thioxanthene derivatives, azurenium derivatives, squarylium derivatives, and porphyrin derivatives can be used. Hen, CMC 1981
And "sensitizers" described in "Specially Functional Materials" (CEM 1986, edited by Chusaburo Ikemori et al.). It should be noted that the present invention is not limited to these, and any other dyes and sensitizers that absorb light in the visible region can be used. These may be used in two or more at any ratio as needed.

The amount of component (B) contained in the composition of the present invention can range from 20 to 200 parts by weight, preferably from 30 to 100 parts by weight, per 100 parts by weight of (A). Department. The amount of the photoinitiator of the component (C) is 0.1 to 20 parts by weight based on 100 parts by weight of the component (A).
Preferably it is 1 to 10 parts by weight. Further, the amount of the sensitizer is from 0.1 to 10 based on 100 parts by weight of the component (A).
It can be in parts by weight, preferably in the range from 0.5 to 5. The amount of component (D) can range from 0.1 to 5 parts by weight, preferably from 0.2 to 0.5 part by weight, per 100 parts by weight of (A). The amount used is limited by the thickness of the photosensitive layer and the optical density of the thickness. That is, it is preferable to use the optical density within a range not exceeding 2.

As described above, these components are appropriately selected, and the photosensitive solution obtained by mixing them at an arbitrary ratio is coated with a known coating means such as a bar coater, an applicator, a doctor blade, a roll coater, a die coater, and a comma coater. Is applied to a substrate such as a glass plate.

When the photosensitive liquid is applied, it may be diluted with an appropriate solvent as required, but in that case, it is necessary to apply the solvent on a substrate and then dry it. Examples of the solvent include dichloromethane, chloroform, acetone, 2-butanone, cyclohexanone, ethyl acetate, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, and 2-methoxyethyl acetate. Ethyl ether,
2-ethoxyethyl ether, 2- (2-ethoxyethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethyl acetate, 2- (2-butoxyethoxy) ethyl acetate,
Examples include tetrahydrofuran and 1,4-dioxane.

Further, since the recordable refractive index difference is limited by the manufacturing method and the recording material, the film thickness is small when the refractive index difference is large, and the film thickness is small when the refractive index difference is small. By increasing the thickness, a light-scattering film can be realized using the composition of the present invention.

The size of the portion having a different refractive index is random and non-regular in order to cause light scattering. However, in order to have a necessary scattering property, the average size is 0.1 μm to 3 μm in diameter.
It is appropriately selected within the range of 00 μm according to the scattering property required for each application.

The distribution of the portions having different refractive indices on the film surface is random and irregular in order to cause light scattering. However, in order to provide necessary scattering, the average refractive index of the entire film is changed. If <n>, the probability distribution is <n
> With a normal distribution. Alternatively, the refractive index n may be distributed according to a probability distribution that takes a maximum value at a minimum value n _min and monotonically decreases exponentially to a maximum value n _max of the refractive index, or a probability distribution that monotonically increases.

Hereinafter, means for producing the light scattering film of the present invention will be described. The light scattering film of the present invention can be produced by an optical exposure means. FIG. 5 is an explanatory diagram showing an example of an optical system manufactured using a random mask pattern. Ultraviolet light emitted from the UV light source 6 is converted into collimated light 8 by a collimating optical system 7 to irradiate a mask master 9.

A photosensitive material 5 is arranged in close contact with the surface of the mask master 9 opposite to the UV irradiation side, and the pattern of the mask master 9 is exposed to light. At this time, since the UV parallel light 8 and the mask master 9 are arranged at a predetermined angle α as shown in the figure, the pattern exposure is performed at a predetermined angle in the photosensitive material 5. This angle is
The angle corresponds to the angle of inclination of a portion having a different refractive index in the light scattering film (that is, the scattering angle θ depending on the incident angle). Therefore, the angle is appropriately set in the range of about 0 to 60 degrees depending on the application. select.

The photosensitive material 5 used here is UV
A photosensitive material that can record exposed and unexposed areas of light in the form of changes in the refractive index. It must have a higher resolving power than the density pattern to be recorded, and be capable of recording patterns in the thickness direction. There is.

The mask master 9 having a predetermined random pattern used in FIG. 5 converts black-and-white pattern data generated from random number calculation using a computer into a metal chrome pattern 11 on a glass substrate 10 by a so-called photolithography technique. Etched ones may be used. Of course, the method of producing the mask master is not limited to the above-mentioned method, and it is well known that a similar mask can be produced by a lithography method using a squirrel plate.

FIG. 6 is an explanatory view showing an example of an optical system for producing a light scattering film having the structure shown in FIG. 2 using a speckle pattern. A ground glass 15 is irradiated with laser light 14 emitted from a laser light source 13. Ground glass 15
The photosensitive material 5 is disposed at a predetermined distance F on the surface opposite to the laser irradiation side, and the photosensitive material 5 is exposed and irradiated with a speckle pattern, which is a complicated interference pattern generated by laser light transmitted and scattered by the ground glass 15. Is done.

At this time, since the ground glass 10 and the photosensitive material 5 are arranged at a predetermined angle α as shown in the figure,
The speckle pattern is exposed at a predetermined angle in the photosensitive material. Since this angle corresponds to the inclination of the portion having a different refractive index in the light scattering film (that is, the scattering peak angle θ depending on the incident angle), the angle is about 0 to 60 degrees depending on the application. Select appropriately within the range.

The laser light source used for recording was an argon ion laser of 514.5 nm, 488 nm or 45 nm.
Among the wavelengths of 7.9 nm, they can be appropriately selected and used according to the sensitivity of the photosensitive material. In addition, other than an argon ion laser, any laser light source having good coherence can be used. For example, a helium neon laser or a krypton ion laser can be used.

The speckle pattern is a bright and dark spot pattern generated when light having good coherence is scattered and reflected or transmitted on a rough surface, and light scattered by minute irregularities on the rough surface interferes in an irregular phase relationship. It is caused by

Description of “Optical Measurement Handbook Asakura Shoten Toshiharu Tada et al., Published November 25, 1994” (p. 26)
6 to p. According to 268), in a speckle pattern in which the density and phase show random values depending on the position, the size of the pattern is inversely proportional to the angle at which the diffusion plate is viewed from the photosensitive material, and the average diameter of the pattern is determined. Is done. Therefore, when the size of the diffusion plate is made larger in the vertical direction than in the horizontal direction, the pattern recorded on the photosensitive material is finer in the vertical direction than in the horizontal direction.

The speckle pattern by the manufacturing method using the optical system shown in FIG. 6 shows that the wavelength λ of the laser beam to be used, the size D of the ground glass, and the distance F between the ground glass and the photosensitive material are as follows.
The average size d of the speckle pattern to be recorded is determined, and is generally expressed by the following equation. d = 1.2λF / D

The average length t of the speckle pattern in the depth direction is represented by t = 4.0λ (F / D) ² .

As described above, the light scattering film of the present invention having a desired three-dimensional refractive index distribution can be obtained by optimizing the values of λ and F / D so as to have optimum scattering properties.

As an example, when λ = 0.5 μm, F / D =
Assuming that 2, d = 1.2 μm and t = 8 μm, the light and shade pattern on the film surface is distributed at an average of 1.2 μm, and the average in the film thickness direction is 8 μm in a direction according to the inclination angle.
m will be distributed.

However, these sizes are merely average sizes, and in fact, portions having different sizes and different refractive indexes are distributed on the surface and inclined in the depth direction. The light scattering film of the present invention as shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to specific examples and comparative examples for clarifying the features of the present invention.

Example 1 Bisphenol epoxy resin epicoat 1004 (epoxy equivalent: 875-97)
5, Yuka Shell Epoxy Co., Ltd. product name) 100 parts by weight,
Tripropylene glycol diacrylate (VISCO
AT-310HP, manufactured by Osaka Organic Chemical Co., Ltd.) 50
Parts by weight and 4,4'-bis (tert-butylphenyl) iodonium hexafluorophosphate 7.5
A photosensitive solution was prepared by mixing and dissolving 0.25 parts by weight of 3,3′-carbonylbis (7-diethylaminocoumarin) in 100 parts by weight of 2-butanone. The photosensitive solution was applied to a blue sheet glass (1.1 mm thick, 5 inch square) with a film thickness of about 5 mm.
It was applied with a doctor blade to a thickness of 0 μm and dried to obtain a recording medium.

The recording medium was exposed from the surface of the recording material (α = 22) with the optical system shown in FIG. 6 using a light obtained by spreading an argon laser (488 nm) as a light source using a lens through a ground glass 15. #, After 40mJ / cm ² ), 80
C. for 1 minute, and the entire surface of the recording medium was irradiated with a high-pressure mercury lamp to fix the recording medium. Furthermore, a light-scattering film was obtained by peeling the cured product from the glass substrate. The thickness of the obtained film was 70 μm.

For evaluation of the obtained light-scattering film, transmittance (wavelength range; 400 to 600 nm) was measured at each angle using a spectrophotometer manufactured by Shimadzu Corporation. Table 1 shows the results (average transmittance of all wavelengths).

[0059]

[Table 1]

Example 2 Bisphenol-based epoxy resin epicoat 1004 (epoxy equivalent: 875-97)
5, in the same manner as in Example 1 except that a hydrogenated bisphenol-based epoxy resin suntote 5100 (epoxy equivalent: 900-1100, trade name, manufactured by Toto Kasei Co., Ltd.) is used instead of the trade name manufactured by Yuka Shell Epoxy Co., Ltd.) To obtain the produced light scattering film. The thickness of the obtained film was 68 μm. Table 2 shows the results.

[0061]

[Table 2]

Example 3 Bisphenol epoxy resin epicoat 1004 (epoxy equivalent: 875-97)
5. Instead of Yuka Shell Epoxy Co., Ltd.), a phenol novolak epoxy resin epicoat 180
The procedure of Example 1 was repeated, except that S65 (epoxy equivalent: 205-220, trade name of Yuka Shell Epoxy Co., Ltd.) was used, to obtain a light-scattering film produced. The thickness of the obtained film was 78 μm. Table 3 shows the results
Shown in

[0063]

[Table 3]

Example 4 Instead of 3,3′-carbonylbis (7-diethylaminocoumarin), 2-N,
Instead of N-dimethylaminobenzylidene) -p-methoxyacetophenone, an argon laser (488) was used as a light source.
nm) was replaced with a krypton laser (413 nm) to operate in the same manner as in Example 1 to obtain a light-scattering film. The thickness of the obtained film is 7
It was 0 μm. Table 4 shows the results.

[0065]

[Table 4]

Example 5 Instead of tripropylene glycol diacrylate (VISCOAT-310HP, trade name, manufactured by Osaka Organic Chemical Co., Ltd.), neopentyl glycol diacrylate (VISCOAT-215, manufactured by Osaka Organic Chemical Co., Ltd.) was used. The same operation as in Example 1 was carried out except using (trade name) to obtain a produced light-scattering film. The thickness of the obtained film was 79 μm. Table 5 shows the results.

[0067]

[Table 5]

Example 6 Bisphenol epoxy resin epicoat 1004 (epoxy equivalent: 875-97)
5. Same as Example 1 except that bisphenol-based epoxy resin Epicoat 1007 (epoxy equivalent: 1750-2200, trade name, manufactured by Yuka Shell Epoxy Co., Ltd.) is used instead of Yuka Shell Epoxy Co., Ltd. To obtain a produced light-scattering film. The thickness of the obtained film was 87 μm. Table 6 shows the results.

[0069]

[Table 6]

Example 7 Bisphenol-based epoxy resin (Epicoat 1004, epoxy equivalent: 875-97)
5, 60 parts by weight of bisphenol-based epoxy resin (Epicoat 1004, epoxy equivalent: 875-975, trade name of Yuka Shell Epoxy Co.) and bromination instead of 100 parts by weight of Yuka Shell Epoxy Co., Ltd. A light-scattering film was obtained in the same manner as in Example 1, except that 40 parts of a bisphenol-based epoxy resin (Araldite 8049SP, epoxy equivalent: 450-490, trade name of Ciba-Geigy Corporation) was used. . The thickness of the obtained film was 87 μm. Table 7 shows the results.

[0071]

[Table 7]

Comparative Example Bisphenol epoxy resin epicoat 1004 (epoxy equivalent: 875-975,
Bisphenol epoxy resin Epicoat 1009 (epoxy equivalent: 2400-3300, Yuka Shell Epoxy Co., Ltd.) instead of Yuka Shell Epoxy Co., Ltd.
The same operation as in Example 1 except that the product name) is used,
A light-scattering film was prepared, but no scattering property was exhibited. The thickness of the obtained film was 90 μm.

[0073]

The use of the composition of the present invention causes light scattering at light incident at a predetermined angle, and conversely functions as a transparent film for light perpendicular to the light. The scattering property has an incident angle selectivity, so that light that requires scattering property and light that does not require scattering property can be separated by the angle of incidence on the film, and as a result, when used in a display device or the like. Thus, a light-scattering film having the effects of improving the brightness, fineness, and contrast of a display without causing unnecessary scattering and reducing the blur of a display image can be manufactured.

Further, when light is incident at an incident angle at which light scattering occurs, it is possible to produce a film which also has scattering anisotropy such that the spread of the scattered light differs vertically and horizontally.
Therefore, scattered light can be emitted only in a necessary direction, and as a result, when used in a display device or the like, there is an effect of improving display brightness and contrast without generating unnecessary scattering.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a light scattering film of the present invention,
The left is a plan view and the right is a cross-sectional view.

FIG. 2 is an explanatory view showing a light scattering film of the present invention;
The left is a plan view and the right is a cross-sectional view.

FIG. 3 is a graph showing an example of the incident angle dependency of the light scattering film of the present invention.

FIG. 4 is a diagram illustrating anisotropy of light scattering possessed by the light scattering film of the present invention.

FIG. 5 is an explanatory view showing an example of an optical system for producing a light scattering film having the structure shown in FIG. 1 using a mask pattern.

FIG. 6 is an explanatory view showing an example of an optical system for producing a light scattering film having the structure shown in FIG. 2 using a speckle pattern.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light scattering film 2 ... Illumination light incident from a scattering direction 3 ... Illumination light incident from a transmission direction 4 ... Plot of measured haze value 5 ... Photosensitive material 6 ... UV light source 7 ... Collimate optical system 8 ... Parallel light 9 ... Mask original plate 10 ... Glass substrate 11 ... Chromium pattern 12 ... Optical fiber 13 ... Laser light source 14 ... Laser light 15 ... Frosted glass 16 ... Beam expander 17 ... Collimator

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 5/02 G02B 5/02 B // C08L 63:00 F term (Reference) 2H042 BA02 BA14 BA15 BA20 4F071 AA42 AC10 AC12 AC15 AC19 AE06 AE22 AF30 AF30Y AF31 AF31Y AH19 BA02 BB02 BC01 BC17 4J011 PA35 PA38 PA43 PA86 PB25 PB40 PC02 PC08 QA02 QA03 QA06 QA08 QA13 SA79 SA83 SA86 SA87 SA88 TA03 UA01 UA05 AC10 AB01 AC10 AD08 AD20 AF01 AF06 AF08 DA00 GA03 GA15 GA22 GA24 GA25 GA26 HA02 HA03 JA09 JA15 KA01

Claims (5)

[Claims] 1. A portion having a different refractive index is distributed in an irregular shape / thickness to form a light and shade pattern having a high or low refractive index, and the portion having a different refractive index is in a thickness direction of the film. A light scattering film having a structure inclined and distributed in a layered manner with respect to light incident on an incident light at an angle along an inclination direction of a portion having a different refractive index, light scattering occurs, and is perpendicular to the inclination direction. The composition that forms a light-scattering film having an incident angle selectivity in terms of light-scattering properties that functions as a mere transparent film with respect to mild light has (A) a compound having cationic polymerizability, and (B) a compound having radical polymerizability. The compound (C) comprises a photoinitiator that generates cationic and radical species by actinic radiation, and there is a difference in the refractive index between (A) the compound having cationic polymerizability and (B) the compound having radical polymerizability. Anisotropic light-scattering film composition characterized. 2. The anisotropic light-scattering film according to claim 1, wherein a sensitizing dye (D) for sensitizing a photoinitiator (C) that generates a cationic species and a radical species by the actinic radiation is added. Composition. 3. The compound (A) having cationic polymerizability.
Is a bisphenol A type epoxy resin or a brominated bisphenol A type epoxy resin having an epoxy equivalent of 400 to 2200, the composition for an anisotropic light-scattering film according to claim 1. 4. The compound having radical polymerizability (B)
Has a refractive index lower than that of the compound having cationic polymerizability (A), is liquid at normal temperature and normal pressure, and has a boiling point of 100 at normal pressure.
The composition for an anisotropic light-scattering film according to claim 1, which is a compound having at least one ethylenically unsaturated bond having a temperature of not less than ° C. 5. The compound (A) having cationic polymerizability.
2. The composition for an anisotropic light-scattering film according to claim 1, wherein 20 to 80 parts by weight of the compound having radical polymerizability (B) is mixed with 100 parts by weight.