JP2001081292A - Composition for anisotropic light scattering film and anisotropic light scattering film - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide anisotropic scattering characteristics (dependence on forward or backward and incident angle) to easily control even the scattering characteristics related to the vertical and horizontal scattering ranges. And a composition suitable for obtaining an anisotropic light-scattering film in which the color of display light does not change depending on the observation position. At least a compound having a molecular weight of 2,000 or less, which is non-reactive with a bisphenol A type epoxy resin or a brominated bisphenol A type epoxy resin (A) upon exposure to form a light and shade pattern, B)
And a radically polymerizable compound (C) having a lower refractive index than (A) and (B), and a photoinitiator (D) that generates a cationic species and a radical species by actinic radiation.

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 and an anisotropic light diffusion film.

[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.

[0004] 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 as in a sandblaster treatment, or is chemically treated by 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 the display are reduced or the 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. 01802 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 properties to make

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 above-mentioned "light diffusion film containing a diffusing material therein", even if the scattering characteristics are given anisotropy (forward or backward), the scattering plate is vertically oriented. It is difficult to control even the lateral scattering characteristics.

As a proposal for a transmission type liquid crystal display device using a hologram as a scattering plate, Japanese Patent Application Laid-Open No. Hei 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.

In order to solve the above-mentioned problems, the present applicant provides the scattering characteristics with anisotropy (forward or backward, and dependence on the incident angle), and makes the scattering characteristics related to the vertical and horizontal scattering ranges. An application of an anisotropic light-scattering film that can be easily controlled even when the display light color does not change depending on the observation position has been filed (Japanese Patent Application No. 10-346743).

[0012]

It is an object of the present invention to provide a composition suitable for obtaining the anisotropic light-scattering film and an anisotropic light-scattering film produced therefrom.

[0013]

According to the first aspect of the present invention, at least a bisphenol A type epoxy resin or a brominated bisphenol A type epoxy resin (A) is exposed to light when forming a light and shade pattern. Non-reactive,
A compound (B) having a molecular weight of 2,000 or less, a compound (C) having a lower refractive index than those of the above (A) and (B), and a radically polymerizable compound, and photoinitiation for generating a cationic species and a radical species by actinic radiation. It is a composition for an anisotropic light-scattering film, characterized by containing an agent (D).
The invention of claim 2 is based on the invention of claim 1 and further comprises a sensitizing dye (E) for sensitizing the above (D).
Is added to the composition for an anisotropic light-scattering film. The invention described in claim 3 is based on the premise of the invention described in claim 1, wherein the (A) has an epoxy equivalent of 400 to 400.
It is a composition for an anisotropic light-scattering film characterized by being 5000. The invention according to claim 4 is based on the premise of the invention according to claim 1, wherein (C) forms an ethylenically unsaturated bond which is liquid at normal temperature and normal pressure and has a boiling point of 100 ° C. or higher at normal pressure. A composition for an anisotropic light-scattering film, which is a compound having at least one compound. The invention according to claim 5 is based on the premise of the invention according to claim 1, characterized in that 20 to 80 parts by weight of (C) is mixed with 100 parts by weight of (A). It is a composition for an isotropic light scattering film. The invention according to claim 6 is an anisotropic light-scattering film obtained by exposing and curing the composition for anisotropic light-scattering film according to claims 1 to 5.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The anisotropic light-scattering film of the present invention (hereinafter simply referred to as a light-scattering film) has a refractive index in which portions having different refractive indexes are distributed in an irregular shape and thickness inside the film. A light and shade pattern consisting of high and low is formed, and the size, shape, distribution of the parts with different refractive indices,
By optimizing along the vertical and horizontal directions on the film surface and along the thickness direction of the film, the scattering characteristics depending on the incident angle can be changed, and light scattering in unnecessary directions can be eliminated. The light is scattered only in the range. The production is carried out by exposing and curing a composition for an anisotropic light-scattering film comprising a cationically polymerizable compound and a radically polymerizable compound, each having a different refractive index.

Here, the light and shade pattern having a high and low refractive index is formed by radical species generated by the photoinitiator (D) according to the light intensity. The generated radical species acts as a polymerization initiator for the compound (C) having radical polymerizability, and the polymerization of the compound (C) starts. At that time, the polymerization proceeds by diffusion movement of the nearby compound (C), but the compound (B) having a molecular weight of 2,000 or less is non-reactive to light exposure when forming a light and shade pattern. Since the radical polymerization does not occur, the concentration of (C) decreases and the concentration of (B) increases in a portion where the light intensity is weak.
Since (B) has a higher refractive index than (C), a light and shade pattern having a higher or lower refractive index is formed according to the light intensity. Finally, the unreacted (C) undergoes radical polymerization by UV exposure or the like, and the carrier (A) is fixed by cationic polymerization.

Hereinafter, the present invention will be described with reference to the drawings.
FIG. 1 shows that the portions having different refractive indices are distributed in an irregular shape and thickness, and the refractive index is high and low (in FIG. 1, it is represented by white and black).
It is an explanatory view showing the light-scattering film 1 on which a light and shade pattern composed of is formed, where the left is a plan view and the right is a cross-sectional view.

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, wherein 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 long,
In addition, in the direction in which the portions having different refractive indices are inclined in a layered manner, the distribution of the refractive index is irregular (the color changes even in the inclined direction).

First, the optical characteristics of the light-scattering film shown in FIGS. 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, if the shape of the portion having a different refractive index is vertically long (or horizontally long), and the light incident on the portion is scattered and emitted, the emitted light from each portion is scattered. 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 ° in the figure), and conversely, the incident angle is symmetric (−60 ° in the figure). Haze value is 20%
This shows the incident angle dependence of the scattering property referred to in this 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 angle of the incident light. It becomes difficult to have dependencies.

The bisphenol A type epoxy resin or brominated bisphenol A type epoxy resin (A) used in the composition of the present invention is a resin represented by the general formula (I), which is crosslinked by heating in the presence of a cationic species. Occurs and hardens. In addition, the epoxy equivalent is 400-5.
000 is desirable. When the epoxy equivalent is less than 400, the epoxy becomes a liquid epoxy and does not play the role of a carrier, and when it is more than 5,000, the diffusion and transfer of (C) becomes difficult and the crosslinking points of the resin decrease, so that the crosslinking after curing is reduced. This is because the density does not increase, which causes a decrease in heat resistance.

[0027]

Embedded image

Non-reactive compound (B) having a molecular weight of 2000 or less used in the composition of the present invention.
Is a compound that needs to have a higher refractive index than a compound having one or more polymerizable ethylenic double bonds in the molecule, and is essentially a liquid or solid compound at room temperature. The compound is non-reactive with light, but may have a functional group that can react by a thermal reaction. In addition, the compound has a molecular weight of 2,000 or less, more preferably 1,000 or less.

Specifically, phthalic acid derivatives such as dimethyl phthalate and butyl benzyl phthalate, triphenyl phosphate, cresyl diphenyl phosphate,
Phosphoric acid esters such as tris (tribromopentyl) phosphate, bisphenol A derivatives, naphthalene derivatives, anthracene derivatives, carbazole derivatives and the like are exemplified, but not limited thereto. Two or more of these compounds may be used.

The compound (C) having at least one polymerizable ethylenic double bond in the molecule is polymerized or cross-linked by irradiation with actinic radiation in the presence of an initiator generating radicals by actinic radiation. A compound having radical polymerizability, for example, a compound containing at least one ethylenically unsaturated bond in a structural unit, a compound containing a polyfunctional vinyl monomer in addition to a monofunctional vinyl monomer, These mixtures may be used. further,
The compound needs to have a lower refractive index than the epoxy resin.

Specifically, high-boiling vinyl monomers such as (meth) acrylic acid, itaconic acid, maleic acid, (meth) acrylamide, diacetone acrylamide, and 2-hydroxyethyl (meth) acrylate, 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.

It is preferable that (C) is a liquid at normal temperature and normal pressure and has a boiling point of 100 ° C. or higher at normal pressure. This is because it is preferably a liquid in order to facilitate diffusion and movement in the resin, and also because it does not volatilize during coating and drying.

Further, it is preferable that 20 to 80 parts by weight of (C) is mixed with 100 parts by weight of (A). If it is out of this range, the concentration distribution due to the diffusion movement of (C) cannot be performed, and as a result, the difference in the refractive index according to the light intensity is reduced, and the scattering property is reduced or the scattering property is not exhibited.

The photoinitiator system (D) which generates a radical species and a cationic species by actinic radiation used in the composition of the present invention is described in J. Am. 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)
Iodonium chlorides such as -butylphenyl) iodonium and bis (p-chlorophenyl) iodonium;
Examples thereof include bromide, a borofluoride salt, a hexafluorophosphate salt, a hexafluoroarsenate salt, and an aromatic sulfonate.

The sensitizing dye (E) for sensitizing the photoinitiator (D) that generates a cationic species and a radical species by actinic radiation according to the present invention includes Michler's ketone,
Organic dye compounds such as benzophenone derivatives such as 4,4'-bis (diethylamino) benzophenone, cyanine or merocyanine derivatives, coumarin derivatives, chalcone derivatives, xanthene derivatives, thioxanthene derivatives, azurenium derivatives, squarylium derivatives, and porphyrin derivatives can be used. "Dye Handbook"
(Shin Okawara et al., Kodansha, 1986), "Chemistry of Functional Dyes" (Shin Okawara et al., CMC, 1981)
And "sensitizers" described in "Special Functional Materials" (ed. By Chusaburo Ikemori et al., CMC, 1986). 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 the photoinitiator contained in the composition of the present invention is 0.1 to 100 parts by weight of the bisphenol A type epoxy resin or the brominated bisphenol A type epoxy resin.
It is 1 to 20 parts by weight, preferably 1 to 10 parts by weight. Further, the amount of the sensitizer is determined based on the amount of bisphenol A type epoxy resin or brominated bisphenol A type epoxy resin 1
It can range from 0.1 to 10 parts by weight, preferably from 0.5 to 5, based on 00 parts by weight. The amount used is limited by the thickness of the photosensitive layer and the optical density of the thickness, or the color of the anisotropic light-scattering film after production. That is, it is preferable to use the resulting anisotropic light-scattering film in an amount close to colorless as long as the optical density does not exceed 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 or a film.

When the photosensitive solution is applied, the solution may be diluted with an appropriate solvent if necessary. In such a case, drying is required after application onto the substrate. 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, 2-methoxy 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.

The photosensitive material using the light-scattering film composition of the present invention may be subjected to a heat treatment at 50 to 120 ° C. after exposure to accelerate the diffusion treatment (C).

Furthermore, since the difference in the refractive index that can be recorded is limited by the manufacturing method and the recording material, the film thickness is small when the difference is large, and is reduced when the 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 portions having different refractive indices is random and non-regular in order to cause light scattering, but has an average size of 0.1 μm to 300 μm in diameter in order to have necessary scattering properties. It is appropriately selected within the range 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, but in order to have necessary scattering properties, the average refractive index of the entire film is required. Is defined as <n>, the probability distribution exhibits a normal distribution centered on <n>. 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.

The photosensitive material 5 is disposed in close contact with the surface of the mask original 9 opposite to the UV irradiation side, and the pattern of the mask original 9 is exposed and irradiated onto the photosensitive material 5. 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 created by random number calculation using a computer into a metal chrome pattern 11 on a glass substrate 10 by a so-called photolithography method. 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 diagram 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, the frosted glass 10 and the photosensitive material 5 are arranged at a predetermined angle α as shown in FIG.
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 or a krypton ion laser of 647.9.
nm, 514.5 nm, 488 nm, 457.9 nm or 413 nm 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 semiconductor 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

According to the description of “Light Measurement Handbook (Asakura Shoten, written by Toshiharu Tamitsu et al., Published on November 25, 1994)” (p. 266 to p. 268), the density and phase are random values depending on the position. In the speckle pattern as shown in the following expression, the average size of the pattern is determined in inverse proportion to the angle at which the diffusion plate is viewed from the photosensitive material. 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 according to 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 this 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 practice, portions having different refractive indices of various sizes large and small centering on these sizes 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.

<Example 1> Bisphenol A type epoxy resin (EP1007, trade name of Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 1750-2200) 50 parts by weight, bisphenol A type epoxy resin (EP1004, Yuka Shell Epoxy) Co., Ltd., trade name, epoxy equivalent 875-9
75) 50 parts by weight, 50 parts by weight of tripropylene glycol diacrylate (VISCOAT-310HP, trade name of Osaka Organic Chemical Co., Ltd.), 1-phenylnaphthalene 4
0 parts by weight, 5.0 parts by weight of 4,4'-bis (tert-butylphenyl) iodonium hexafluorophosphate, 0.2 parts by weight of 4,4'-bis (diethylamino) benzophenone and 100 parts by weight of 2-butanone Was dissolved and used as a photosensitive solution. The photosensitive solution was applied to blue sheet glass (1.1 mm thick, 5 inch square) with a doctor blade and dried to obtain a photosensitive material.

The photosensitive material is exposed from the surface of the recording material through a ground glass 15 by using a light obtained by expanding a krypton laser (413 nm) as a light source using a lens in the optical system shown in FIG. 6 (α = 22 °). , 10mJ / cm ² ), 85 ° C
After heating for 5 minutes at, 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 30 microns.

For evaluation, 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).

[Table 1] Measurement angle (°) 0 10 20 22 25 30 40 Transmittance (%) 82 82 80 72 25 14 14

Example 2 Example 1 except that butylbenzyl phthalate was used instead of 1-phenylnaphthalene.
The same operation as described above was carried out to obtain the produced light-scattering film. The thickness of the film obtained was 31 microns. Table 2 shows the results.

[Table 2] Measurement angle (°) 0 10 20 22 25 30 40 Transmittance (%) 83 83 81 70 28 16 15

Example 3 A light-scattering film was produced in the same manner as in Example 1, except that cresyl diphenyl phosphate was used instead of 1-phenylnaphthalene. The thickness of the film obtained was 32 microns. The results are shown in [Table 3].

[Table 3] Measurement angle (°) 0 10 20 22 25 30 40 Transmittance (%) 80 80 78 66 33 23 22

Example 4 A light-scattering film was produced in the same manner as in Example 1 except that ethylcarbazole was used instead of 1-phenylnaphthalene. The thickness of the obtained film was 30 microns. Table 4 shows the results.

[Table 4] Measurement angle (°) 0 10 20 22 25 30 40 Transmittance (%) 82 82 80 59 27 18 18

<Example 7> Instead of 4,4'-bis (diethylamino) benzophenone, carbonylbis (p
-Dimethylaminobenzylidene), and a light-scattering film was produced in the same manner as in Example 1 except that an argon laser (514.5 nm) was used instead of a krypton laser (413 nm) as a light source. The thickness of the film obtained was 31 microns. Table 5 shows the results.

[Table 5] Measurement angle (°) 0 10 20 22 25 30 40 Transmittance (%) 80 80 80 65 35 15 15 15

<Example 6> Instead of tripropylene glycol diacrylate (VISCOAT-310HP, trade name of Osaka Organic Chemical Co., Ltd.), neopentyl glycol diacrylate (VISCOAT-215, trade name of Osaka Organic Chemical Co., Ltd.) was used. ) Was carried out in the same manner as in Example 1 except that (1) was used to obtain a produced light-scattering film. The thickness of the obtained film was 30 microns. Table 6 shows the results
Shown in

[Table 6] Measurement angle (°) 0 10 20 22 25 30 40 Transmittance (%) 80 80 79 69 41 26 25

<Example 7>4,4'-bis (tert-
A light-scattering film was produced in the same manner as in Example 1 except that trichloromethyltriazine was used instead of (butylphenyl) iodonium hexafluorophosphate. The thickness of the film obtained was 32 microns. Table 7 shows the results.

[Table 7] Measurement angle (°) 0 10 20 22 25 30 40 Transmittance (%) 83 83 80 61 30 20 19

Example 8 A bisphenol A type epoxy resin (EP10 brominated bisphenol) was used instead of 50 parts by weight of bisphenol A type epoxy resin (EP1007, trade name of Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 1750-2200). A type epoxy resin (YL6167, trade name, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 210
(0-2300) The same operation as in Example 1 was carried out except using 50 parts by weight, to obtain a light-scattering film produced. The thickness of the resulting film was 29 microns. Table 7 shows the results.

[Table 7] Measurement angle (°) 0 10 20 22 25 30 40 Transmittance (%) 81 81 79 46 25 19 18

[0075]

The light-scattering film produced by using the composition according to the present invention causes light scattering for light incident at a predetermined angle, and conversely, as a transparent film for light perpendicular thereto. By functioning, the light 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 incident angle to the film, and as a result, the display device In such a case, it is possible to improve the brightness, fineness and contrast of display without unnecessary scattering, and to reduce the blur of a display image.

Further, when light is incident at an incident angle at which light scattering occurs, it is possible to produce a film having a scattering anisotropy in which the spread of the scattered light differs vertically and horizontally.
Therefore, scattered light can be emitted only in a necessary direction. 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.

[0077]

[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 an explanatory diagram of anisotropic light scattering of 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]

 Reference Signs List 1 light scattering film 2 illumination light incident from scattering direction 3 illumination light incident from transmission direction 4 plot of actually 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 chrome pattern 12 Optical fiber 13 Laser light source 14 Laser light 15 Ground glass 16 Beam expander 17 Collimator

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Claims (6)

[Claims] 1. A compound which is non-reactive with at least bisphenol A type epoxy resin or brominated bisphenol A type epoxy resin (A) upon exposure to form a light and shade pattern and has a molecular weight of 2,000 or less. (B)
And a radically polymerizable compound (C) having a lower refractive index than (A) and (B), and a photoinitiator (D) that generates a cationic species and a radical species by actinic radiation. A composition for an anisotropic light scattering film. 2. The composition for an anisotropic light-scattering film according to claim 1, further comprising a sensitizing dye (E) for sensitizing said (D). 3. The method according to claim 1, wherein (A) has an epoxy equivalent of 400 to 50.
The composition for an anisotropic light-scattering film according to claim 1, wherein the composition is 00. 4. The compound according to claim 1, wherein (C) is a compound which is liquid at normal temperature and pressure and has at least one ethylenically unsaturated bond having a boiling point of 100 ° C. or higher at normal pressure. Item 6. The composition for an anisotropic light-scattering film according to Item 1. 5. The method according to claim 5, wherein (C) is added to 100 parts by weight of (A).
The composition for an anisotropic light-scattering film according to claim 1, wherein 20 to 80 parts by weight is mixed. 6. An anisotropic light scattering film obtained by exposing and curing the composition for an anisotropic light scattering film according to claim 1.