JP5045481B2 - Light diffusion plate - Google Patents

Description

The present invention relates to a light diffusing plate.

As shown in FIG. 1, the color liquid crystal display device includes a liquid crystal cell (1), polarizing sheets (2) disposed on both sides thereof, and a color filter for coloring transmitted light that passes through the liquid crystal cell for color display ( 3) and an image display device including a light source (5) that illuminates the image display unit (4) from the back side, and is widely used as a liquid crystal television, for example. Yes. A light diffusing plate (6) for uniformly illuminating the image display unit (4) with light from the light source (5) is incorporated on the optical path between the light source (5) and the image display unit (4). [Patent Document 1: Japanese Patent Laid-Open No. 2001-305335].

As the light diffusing plate (8), those made of a resin composition containing a transparent resin such as polystyrene and a diffusing agent are widely used, and sufficient light can be transmitted with a small amount of diffusing agent used. What can be diffused is required.

JP 2001-305335 A

Therefore, the present inventors have intensively studied to develop a light diffusing plate exhibiting high light diffusibility even with a small amount of diffusing agent used, resulting in the present invention.

That is, the present invention provides a light diffusing plate comprising a transparent resin and a transparent resin composition containing the following diffusing agent.

Diffusing agent: average particle size of 0.6 to 0.9 μm, standard deviation of average particle size of 0.01 to 0.5 μm
m, a diffusing agent having an absolute value | Δn | of the refractive index difference from the transparent resin of 0.05 or more

Since the light diffusing plate of the present invention exhibits high light diffusibility even when the amount of the diffusing agent used is small, the amount of the diffusing agent used can be reduced, and a thinner light diffusing plate can be obtained.

Hereinafter, the present invention will be described in detail.
Examples of the transparent resin used in the present invention include styrene resin, polymethyl methacrylate, polycarbonate, cycloolefin polymer, cycloolefin copolymer, polypropylene and the like. Particularly, from the viewpoint of moisture absorption resistance, polystyrene, styrene / methyl methacrylate copolymer are used. Polymer, cycloolefin polymer, cycloolefin copolymer, polypropylene,
In particular, polystyrene is preferred.

The styrene resin used in the present invention has a styrene monomer unit content of 50 to 100.
% By mass. As the styrenic monomer, substituted styrenes can be used in addition to styrene. Examples of the substituted styrenes include halogenated styrenes such as chlorostyrene and bromostyrene, and alkyl styrenes such as vinyltoluene and α-methylstyrene. Styrenic monomers may be used alone or in combination of two or more.

The monomer copolymerized with the styrene monomer is not particularly limited as long as it is a copolymerizable monomer. For example, methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, methacrylic acid Methacrylate esters such as phenyl, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, and the like;
Methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate,
Acrylic esters such as phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and the like;
Unsaturated acids such as acrylic acid,
Examples include acrylonitrile, methacrylonitrile, maleic anhydride, phenylmaleimide, cyclohexylmaleimide, glutaric anhydride, glutarimide, and the like. These monomers can be used alone or in combination of two or more.

As the transparent resin used in the present invention, a commercially available transparent resin can be used as long as the characteristics as a light diffusion plate are not impaired.

For polystyrene, Toyostyrene HRM30, HRM40, P made by Toyo Styrene
Examples include G9305 manufactured by S Japan, G690N and G797N manufactured by Nippon Polystyrene.

If it is a styrene / methyl methacrylate copolymer, “Atrete” manufactured by Nippon A & L
Series, Nippon Steel Chemical "Estyrene" series, etc. are exemplified.

Examples of the cycloolefin polymer include “Zeonor” series manufactured by Nippon Zeon, “Arton” series manufactured by JSR, and the like.

Examples of the cycloolefin copolymer include “Topas” series manufactured by Ticona, “Apel” series manufactured by Mitsui Chemicals, and the like.

Examples of polypropylene include “Noblen” series manufactured by Sumitomo Chemical.

As polycarbonate, Sumitomo Dow “Caliber” series, Teijin Chemicals “Panlite”
Examples include the series, “Taflon” series made by Idemitsu Kosan, and “Iupilon” series made by Mitsubishi Engineering Plastics.

The diffusing agent used in the present invention is capable of diffusing light transmitted through the light diffusing plate of the present invention by being dispersed in a transparent resin, and the average particle size thereof is 0.6 to 0. 0.9 μm, preferably 0.65 to 0.85 μm. The addition amount of the diffusing agent can be suppressed if it is 0.1 μm or more and 1 μm or less, and the standard deviation is preferably 0.5 or less, more preferably 0.2 or less, which meets the object of the present invention. . The addition amount of the diffusing agent can be arbitrarily selected depending on the absolute value | Δn | of the refractive index difference between the transparent resin and the diffusing agent and the required total light transmittance. On the other hand, it is 0.1-20 mass parts. The average particle size and the standard deviation of the average particle size described in the present invention are 5000 times or 500 times.
From the SEM image of the diffusing agent taken at 00 ×, 40 particles are randomly measured by the three-point circle radius method to calculate the diffusing agent diameter, that is, the particle diameter. The average value and standard deviation of the particle diameter of the obtained diffusing agent are shown.

The material of the diffusing agent used in the present invention is not particularly limited, but silicone-based particles, silica-based particles, acrylic particles, styrene-based particles, metal oxide-based particles, etc., as long as the refractive index difference from the transparent resin can be secured. Any particle can be selected. Absolute value of refractive index difference with transparent resin | Δn
| Is preferably | Δn | ≧ 0.05, more preferably | Δn | ≧ 0.10. If the refractive index difference is 0.05 or more, the addition amount of the diffusing agent can be suppressed, which meets the object of the present invention.

Examples of inorganic fine particles include calcium carbonate particles, barium sulfate particles, titanium oxide particles, aluminum hydroxide particles, silica particles, glass particles, talc particles, mica particles, white carbon particles, magnesium oxide particles, and zinc oxide particles. And may be surface treated with a surface treating agent such as a fatty acid.

Organic fine particles include, for example, crosslinked resin particles such as crosslinked styrene resin particles, crosslinked acrylic resin particles and crosslinked siloxane resin particles, high molecular weight styrene resin particles having a high molecular weight, and high molecular weight acrylic resin particles. Examples thereof include molecular weight resin particles. The crosslinked resin particles are resin particles having a gel fraction of 10% or more when dissolved in acetone, and the high molecular weight resin particles have a weight average molecular weight (Mw) of 500,000 to 5,000,000. Resin particles.

As the styrene resin particles, for example, (1) high molecular weight resin particles obtained by polymerizing styrene monomers, or double bonds capable of radical polymerization containing 50% by weight or more of styrene monomer units. High molecular weight resin particles obtained by polymerizing one monomer in the molecule,

(2) A crosslinked resin particle obtained by polymerizing a monomer having at least two double bonds capable of radical polymerization with a styrene monomer, or containing 50% by weight or more of a styrene monomer unit And crosslinked resin particles obtained by polymerizing a monomer having one radical-polymerizable double bond in the molecule and a monomer having at least two radical-polymerizable double bonds in the molecule. .

Examples of the styrenic monomer include styrene and its derivatives. Examples of the styrene derivative include, but are not limited to, halogenated styrene such as chlorostyrene and bromostyrene, alkyl-substituted styrene such as vinyltoluene, and α-methylstyrene. These styrenic monomers are used alone or in combination of two or more.

The monomer having one double bond capable of radical polymerization in the molecule is not particularly limited as long as it is other than the above-mentioned styrene monomer component. For example, methyl methacrylate, ethyl methacrylate,
Methacrylic acid esters such as butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate,
Cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-acrylic acid
Acrylic esters such as ethylhexyl and 2-hydroxyethyl acrylate, acrylonitrile and the like can be mentioned. Of these, alkyl methacrylates such as methyl methacrylate are preferred. These monomers are used alone or in combination of two or more.

The monomer having at least two double bonds capable of radical polymerization in the molecule is one that is copolymerizable with the above-mentioned monomer and excludes a conjugated diene. Specifically, for example, 1,4-butanediol di (meth) acrylate, alkyldiol di (meth) acrylates such as neopentyl glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) ) Acrylate, tetraethylene glycol di (meth)
Alkylene glycol di (meth) acrylates such as acrylate, propylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate;
Examples thereof include aromatic polyfunctional compounds such as divinylbenzene and diallyl phthalate, (meth) acrylates of polyhydric alcohols such as trimethylolpropane tri (meth) acrylate and pentaerythritol tetra (meth) acrylate. These monomers are used alone or in combination of two or more. “(Meth) acrylate” means “methacrylate” and “acrylate”.

As the acrylic resin particles, for example, (1) high molecular weight resin particles obtained by polymerizing acrylic monomers, or double bonds capable of radical polymerization containing 50% by weight or more of acrylic monomer units. High molecular weight resin particles obtained by polymerizing one monomer in the molecule,

(2) Crosslinked resin particles obtained by polymerizing a monomer having at least two double bonds capable of radical polymerization with an acrylic monomer, or containing 50% by weight or more of an acrylic monomer unit And crosslinked resin particles obtained by polymerizing a monomer having one radical-polymerizable double bond in the molecule and a monomer having at least two radical-polymerizable double bonds in the molecule. .

Examples of the acrylic monomer include methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, methyl acrylate, Examples include ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, methacrylic acid, and acrylic acid. These acrylic monomers are used alone or in combination of two or more.

The monomer having one radical-polymerizable double bond in the molecule is not particularly limited as long as it is other than the acrylic monomer, and examples thereof include styrene and derivatives thereof. Examples of the styrene derivative include halogenated styrene such as chlorostyrene and bromostyrene, alkyl-substituted styrene such as vinyl toluene, and α-methylstyrene. Of these, styrene is preferred. These monomers are used alone or in combination of two or more.

Monomers having at least two radically polymerizable double bonds in the molecule are those that are copolymerizable with the above monomers and exclude conjugated dienes, and can be selected from the monomers described above. That's fine.

Styrenic resin particles, acrylic resin particles, monomers are suspension polymerization method, micro suspension polymerization method,
It can be produced by polymerization by a usual polymerization method such as an emulsion polymerization method, a dispersion polymerization method or a seed polymerization method.

The shape of the diffusing agent used in the present invention is not particularly limited, but spherical particles are preferred.

The blending method and kneading method in the present invention may be carried out by a method applied to ordinary thermoplastic resins, such as a ribbon blender, a Henschel mixer, a Banbury mixer, a drum tumbler, a single-screw extruder, a twin-screw extruder, It can be performed by a multi-screw extruder or the like.

Although the thickness of the light diffusing plate using the method of this invention is not specifically limited, Usually, it is 1-5 mm.

Resins include sodium alkyl sulfonate, sodium alkyl sulfate, stearic acid monoglyceride, polyether ester amide and other antistatic agents, hindered phenols and other antioxidants, phosphate esters and other flame retardants, palmitic acid and stearyl alcohol, etc. Lubricants, light stabilizers such as hindered amines, antioxidants such as hindered phenols, various dyes, fluorescent brighteners, benzotriazole UV absorbers, benzophenone UV absorbers, cyanoacrylate UV absorbers, malonic acid esters Additives such as ultraviolet absorbers, oxalic anilide ultraviolet absorbers, and ultraviolet absorbers of acetic ester ultraviolet absorbers may be contained. These additives are used alone or in combination of two or more.

The light diffusing plate of the present invention is used as a multilayer light diffusing plate by laminating an ultraviolet absorbing layer made of a resin composition containing methyl methacrylate-styrene copolymer and an ultraviolet absorber on one or both sides thereof. Also good. By using such a multilayer light diffusion plate, deterioration due to ultraviolet rays can be prevented. Examples of UV absorbers include benzotriazole UV absorbers, benzophenone UV absorbers, cyanoacrylate UV absorbers, malonic ester UV absorbers, oxalic anilide UV absorbers, and acetate ester UV absorbers. .

The ultraviolet absorbing layer may contain a diffusing agent. Examples of the diffusing agent include crosslinked acrylic resin particles and crosslinked styrene resin particles.

Since the light diffusing plate of the present invention contains the above-mentioned diffusing agent defined in the present invention in the transparent resin, the total light transmittance of the transparent resin can be lowered even if the amount of the diffusing agent used is small. . Since the transparent resin whose total light transmittance is lowered by the diffusing agent can sufficiently diffuse the light transmitted therethrough, the light diffusing plate of the present invention can transmit light with a small amount of the diffusing agent used. Can be diffused sufficiently.

The light diffusion plate of the present invention is suitably used for a color liquid crystal display device as shown in FIG. This color liquid crystal display device comprises a liquid crystal cell (1), polarizing sheets (2) arranged on both sides thereof, and a color filter (3) for coloring transmitted light that passes through the liquid crystal cell for color display. It is an image display apparatus provided with the image display part (4) and the light source (5) which illuminates this image display part (4) from the back side. A light diffusion plate (8) for uniformly illuminating the image display unit (4) with light from the light source (5) is incorporated on the optical path between the light source (5) and the image display unit (4). I'm.

EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited at all by these Examples. Parts and% are based on weight unless otherwise specified.

[Measurement method of total light transmittance]
The total light transmittance Tt was measured using a haze transmittance meter (HR-100 manufactured by Murakami Color Research Laboratory) in accordance with JIS K 7361. The more the transmitted light is sufficiently diffused, the smaller the total light transmittance is.
(Particle size measurement method)
A diffusing agent was pressure-bonded to a sample stage and carbon was deposited to prepare a sample piece. The obtained sample piece was subjected to Comparative Example 3 using an electrolytic emission scanning electron microscope FE-SEM S-4200 manufactured by Hitachi, Ltd.
The diffusing agent SEM image was observed at 50000 times for the other and 5000 times for the others. From the SEM image of the obtained diffusing agent, the radius of the diffusing agent was measured by a three-point circle radius method. The particle size of the diffusing agent was calculated from the radius of the obtained diffusing agent.
[Definition of average particle size and standard deviation of average particle size]
Forty particles were randomly measured by the above particle size measurement method, and the average value and standard deviation of the diffusing agent particle size were calculated.

Comparative Example 1
One part of silicone particles having a refractive index of 1.43, an average particle diameter of 2.49 μm, and a standard deviation of the average particle diameter of 0.14 μm was added and dry blended to 100 parts of polystyrene (HRM40 refractive index: 1.59 made by Toyo Styrene). This mixture was extruded at 190 ° C. to 260 ° C. using a Tanabe Plastics 40 mm single screw extruder equipped with a multi-manifold die to obtain a single layer plate having a thickness of 2 mm. At this time, the total light transmittance (hereinafter referred to as Tt) was 56.2%.

Comparative Example 2
Comparative Example 1 was obtained by adding 1 part of silicone particles having a refractive index of 1.43, an average particle diameter of 2.17 μm, and a standard deviation of the average particle diameter of 0.29 μm to 100 parts of polystyrene (HRM40 having a refractive index of 1.59) manufactured by Toyo Styrene. The Tt of a 2 mm thick single layer board obtained by the same method is 54.8%.
Met.

Example 1
Comparative Example 1 was obtained by adding 1 part of silicone particles having a refractive index of 1.43, an average particle diameter of 0.67 μm, and a standard deviation of the average particle diameter of 0.07 μm to 100 parts of polystyrene (HRM40 refractive index of 1.59 made by Toyo Styrene). The Tt of a 2 mm thick single layer plate obtained by the same method is 49.6%.
Met.

Comparative Example 3
Comparative Example 1 was performed by adding 1 part of silicone particles having a refractive index of 1.43, an average particle diameter of 0.12 μm, and a standard deviation of the average particle diameter of 0.01 μm to 100 parts of polystyrene (HRM40 refractive index of 1.59 made by Toyo Styrene). The Tt of the 2 mm thick single layer plate obtained by the same method as above was 55.0
%Met.

Comparative Example 4
Comparative Example with 1 part of acrylic resin particles having a refractive index of 1.49, an average particle diameter of 2.44 μm, and a standard deviation of the average particle diameter of 0.52 μm per 100 parts of polystyrene (HRM40 refractive index 1.59 made by Toyo Styrene) The Tt of the 2 mm single layer board obtained by the same method as in Example 1 was 69.3%.

Comparative Example 5
Comparative Example with 1 part of acrylic resin particles having a refractive index of 1.49, an average particle diameter of 1.00 μm, and a standard deviation of the average particle diameter of 0.06 μm per 100 parts of polystyrene (HRM40 refractive index 1.59 made by Toyo Styrene) The Tt of the 2 mm single layer plate obtained by the same method as in Example 1 was 68.0%.

Example 2
Comparative Example with one part of acrylic resin particles having a refractive index of 1.49, an average particle diameter of 0.85 μm, and a standard deviation of the average particle diameter of 0.03 μm per 100 parts of polystyrene (HRM40 refractive index 1.59 made by Toyo Styrene) The Tt of the 2 mm single layer board obtained by the same method as in Example 1 was 55.1%.

Comparative Example 6
Comparative Example 1 part of acrylic resin particles having a refractive index of 1.49, an average particle diameter of 0.50 μm, and a standard deviation of the average particle diameter of 0.04 μm are added to 100 parts of polystyrene (HRM40 refractive index 1.59) manufactured by Toyo Styrene. The Tt of the 2 mm single layer plate obtained by the same method as in Example 1 was 70.2%.

The results are summarized in Table 1 and Table 2 below.

[Table 1]
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Comparative Example 1 Comparative Example 2 Example 1 Comparative Example 3
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Average particle diameter (μm) 2.49 2.17 0.67 0.12
Standard deviation of average particle size 0.14 0.29 0.07 0.02
Total light transmittance Tt (%) 56.2 54.8 49.6 55.0
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[Table 2]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Comparative Example 4 Comparative Example 5 Example 2 Comparative Example 6
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Average particle diameter (μm) 2.44 1.00 0.85 0.50
Standard deviation of average particle size 0.52 0.06 0.03 0.04
Total light transmittance Tt (%) 69.3 68.0 55.1 70.2
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Example 3
[Production of diffusing agent mixture A]
98.8 parts by weight of polystyrene (“HRM40” refractive index 1.59 made by Toyo Styrene), acrylic resin particles [refractive index 1.48, average particle size 0.88 μm, standard deviation 0.06 μm in particle size] 1.0 A diffusing agent mixture obtained by dry blending a mixture of 0.1 part by mass of an ultraviolet absorber (“SUMISORB 200” manufactured by Sumitomo Chemical Co., Ltd.) and 0.1 part by mass of a processing stabilizer (“SUMILIZER GP” manufactured by Sumitomo Chemical Co., Ltd.). A was obtained.

[Production of UV absorber compound B]
Styrene-methyl methacrylate copolymer [“Estyrene MS200NT” manufactured by Nippon Steel Chemical Co., Ltd., styrene unit 80% by mass, methyl methacrylate unit 20% by mass] 90.9 parts by mass, crosslinked acrylic resin particles [refractive index 1. 49, average particle diameter 30 μm] 8.0 parts by weight, processing stabilizer [Sumitomo Chemical Co., Ltd. “Sumilyzer GP”] 0.1 part by mass, ultraviolet absorber [ADEKA Co., Ltd. “Adeka Stub LA31”] 1.0 part by mass The mixture was pelletized by a twin screw extruder at 180 ° C. to 250 ° C. to obtain a pellet-like ultraviolet absorber compound B.

[Manufacture of multilayer light diffusing plate]
The diffusing agent mixture A obtained above is supplied to an extruder having a screw diameter of 120 mm and melt kneaded at 190 to 250 ° C., while the ultraviolet absorbent compound B obtained above is supplied to an auxiliary extruder having a screw diameter of 45 mm. The feed block and the T-die are melt-kneaded at an extruder temperature of 210 to 250 ° C., and the ultraviolet absorbing layer led from the ultraviolet absorber compound B is laminated on both surfaces of the light diffusing layer led from the diffusing agent mixture A. A multilayer light diffusion plate having a three-layer structure in which an ultraviolet absorption layer [thickness 0.05 mm] is laminated on both sides of a light diffusion layer [thickness 1.9 mm] by co-extrusion at a T die temperature of 245 to 255 ° C. Obtained.

[Evaluation of multilayer light diffusion plate]
The total light transmittance of the multilayer light diffusing plate obtained above was 57.0%.
The multilayer light diffusing plate obtained above was cut into a size of 147 mm × 147 mm and used as a sample. Remove the light diffusing plate from the direct type backlight unit constituting the commercially available liquid crystal television [Sharp's “LC-20S4”], incorporate the sample obtained above instead, turn on the backlight, and multipoint luminance meter [ (Eye System Co., Ltd., “Eye Scale 3”) was used to measure the luminance L, chromaticity x, and chromaticity y at 900 points arbitrarily selected from the range of 70 mm × 70 mm near the center of the sample. Difference between maximum value and minimum value (luminance unevenness, ΔL), number average of luminance (average luminance), number average of chromaticity x (average chromaticity x) and number average of chromaticity y (average chromaticity y) As a result, luminance unevenness was 1.03, average luminance was 5313 Cd / m ² , average chromaticity x was 0.285, and average chromaticity y was 0.267.

Comparative Example 7
98.8 parts by weight of polystyrene [“HRM40” refractive index 1.59 made by Toyo Styrene], acrylic resin particles [refractive index 1.48, average particle size 2.44 μm, standard deviation of particle size 0.52 μm] 1.0 A diffusing agent mixture obtained by dry blending a mixture of 0.1 part by mass of an ultraviolet absorber (“SUMISORB 200” manufactured by Sumitomo Chemical Co., Ltd.) and 0.1 part by mass of a processing stabilizer (“SUMILIZER GP” manufactured by Sumitomo Chemical Co., Ltd.). C was obtained.

Except for using the diffusing agent mixture C obtained above in place of the diffusing agent mixture A used in Example 3, the same operation as in Example 3 was carried out to absorb UV light on both surfaces of the light diffusion layer [thickness 1.9 mm]. A multilayer light diffusing plate having a three-layer structure in which layers [thickness 0.05 mm] were laminated was obtained and evaluated in the same manner as in Example 3. The results are shown in Table 3.

[Table 3]
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Example 3 Comparative Example 7
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Average particle diameter (μm) 0.85 2.44
Standard deviation of average particle size 0.03 0.52
Total light transmittance Tt (%) 57.0 70.4
Brightness unevenness 1.03 1.16
Average luminance (Cd / m ² ) 5313 6026
Average chromaticity x 0.285 0.283
Average chromaticity y 0.267 0.265
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It is sectional drawing which shows an example of a color liquid crystal display device typically.

Claims (5)

A light diffusing plate comprising a transparent resin composition containing polystyrene and the following diffusing agent.
Diffusing agent: average particle diameter is 0.6 to 0.9 μm, standard deviation of average particle diameter is 0.01 to 0.2 μm, and absolute value | Δn | of the refractive index difference from the transparent resin is 0.05 or more A diffusion agent A light diffusing plate comprising a transparent resin and a transparent resin composition containing the following diffusing agent.
Diffusing agent: average particle diameter is 0.6 to 0.9 μm, standard deviation of average particle diameter is 0.01 to 0.2 μm, and absolute value | Δn | of the refractive index difference from the transparent resin is 0.05 or more Ah is, Oh Ru diffusing agent in acrylic resin particles A light diffusing plate comprising a transparent resin composition containing polystyrene and the following diffusing agent.
Diffusing agent: average particle diameter is 0.6 to 0.9 μm, standard deviation of average particle diameter is 0.01 to 0.2 μm, and absolute value | Δn | of the refractive index difference from the transparent resin is 0.05 or more Ah is, Oh Ru diffusing agent in acrylic resin particles 4. The light diffusing plate according to claim 1, wherein the amount of the diffusing agent used is 0.5 to 2 parts by weight with respect to 100 parts by weight of the transparent resin. A layer made of a resin composition containing a methyl methacrylate-styrene copolymer and an ultraviolet absorber is laminated on one side or both sides of the light diffusing plate according to any one of claims 1 to 4. A multilayer light diffusing plate characterized.

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