KR20170095126A - Composition for use in light guide plate and light guide plate - Google Patents

Abstract

Provided is a composition for a light guide plate, which can manufacture a light guide plate capable of uniformly emitting light with a higher luminance to a light emission surface side and has excellent storage stability. The composition for a light guide plate according to the present invention comprises: light diffusion particles (A); and a dispersion medium (B), wherein reflectance in 300 to 380 nm wavelength of a cured film with 10 m thickness manufactured by using the composition is 0 to 50% and reflectance in 400 to 800 nm wavelength of the cured film with 10 m thickness manufactured by using the composition is 30 to 99%.

Description

TECHNICAL FIELD [0001] The present invention relates to a composition for a light guide plate and a light guide plate,

 The present invention relates to a composition for a light guide plate and, in particular, to a light guide plate suitable for an edge light type surface light emitting device.

BACKGROUND ART A surface light emitting device used in a liquid crystal display panel or a signboard is known as a direct light type in which a light source is arranged in a plane shape to form a surface uniform light emission by a diffusion plate or the like and an edge light type in which a light source is arranged in an end surface of a light guide plate.

The edge light type surface light emitting device includes a light source and a light guide plate. The light guide plate includes a light guiding plate and a light diffusing portion. Light from the light source propagates inside the light guiding plate and is emitted in a planar shape by a light diffusing portion disposed on the surface of the light guiding plate. As described in Patent Documents 1 to 4, such a light guide plate is manufactured by coating a light guide plate containing a light diffusing particle on a light guide plate to fabricate a light diffusion portion.

Japanese Laid-Open Patent Publication No. 09-145937 Japanese Patent Application Laid-Open No. 2010-146771 Japanese Laid-Open Patent Publication No. 2012-216528 Japanese Laid-Open Patent Publication No. 2012-178345

Such a surface light emitting device is required to further improve energy efficiency, and a technique for sufficiently extracting light supplied from the light source to the light guide substrate to the light emission surface side of the light guide substrate is required more efficiently.

Therefore, some of the aspects of the present invention solve the above-mentioned problems at least partly, thereby making it possible to manufacture a light guide plate capable of uniformly emitting light with a higher luminance toward the light exit surface side, And to provide a composition for use in the present invention.

The present invention has been made to solve at least part of the above-mentioned problems, and can be realized as the following aspects or applications.

[Application Example 1]

An aspect of the composition for a light guide plate according to the present invention is that,

As a composition for a light guide plate containing light diffusing particles (A) and a dispersion medium (B)

Wherein the reflectance at a wavelength of 300 to 380 nm is 0 to 50% and the reflectance at a wavelength of 400 to 800 nm is 30 to 99% of a 10 μm thick cured film produced using the composition.

[Application example 2]

In the composition for a light guide plate of Application Example 1,

The value (particle variation coefficient) obtained by dividing the standard deviation of the particle size distribution of the light-diffusing particles (A) by the number average particle size may be 0.01 to 0.2.

[Application Example 3]

In the composition for a light guide plate of Application Example 1 or Application Example 2,

The ratio (Rmax / Rmin) of the major axis (Rmax) and the minor axis (Rmin) of the light diffusing particles (A) may be in the range of 1.01 to 1.2.

[Application example 4]

In the composition for a light guide plate of any one of Application Examples 1 to 3,

The dispersion medium (B) may contain a photopolymerizable component.

[Application Example 5]

In the composition for a light guide plate according to any one of Application Examples 1 to 4,

In addition, it may contain a radical scavenger (D).

[Application Example 6]

In the composition for a light guide plate according to any one of Application Examples 1 to 5,

In addition, it may contain an isothiazoline-based compound.

[Application Example 7]

According to an aspect of the light guide plate according to the present invention,

And is manufactured using the composition for a light guide plate of any one of Application Examples 1 to 6.

According to the composition for a light guide plate of the present invention, it is possible to manufacture a light guide plate which can uniformly emit light to the light exit surface side with higher luminance by forming the light diffusion portion by applying the composition to the light guide plate. The composition for a light guide plate according to the present invention is also excellent in storage stability.

1 is a schematic cross-sectional view showing an example of an edge light type surface light emitting device.
2 is a plan view of the side of the light guide plate on which the light diffusion portion is formed.
3 is an explanatory diagram schematically showing the concept of the long diameter and the short diameter of the light-diffusing particle (A).
4 is an explanatory diagram schematically showing the concept of the long diameter and the short diameter of the light-diffusing particle (A).
5 is an explanatory diagram schematically showing the concept of the long diameter and the short diameter of the light-diffusing particle (A).
6 is an explanatory diagram schematically showing the concept of the release particle.
7 is an explanatory diagram schematically showing the concept of the release particle.
8 is an explanatory diagram schematically showing the concept of the release particle.
Fig. 9 is an explanatory diagram schematically showing the concept of the release particle.
10 is an explanatory diagram schematically showing the concept of the release particle.
11 is an explanatory diagram schematically showing the concept of the release particle.

(Mode for carrying out the invention)

Hereinafter, preferred embodiments according to the present invention will be described in detail. It should be understood that the present invention is not limited to the embodiments described below, but includes various modifications embodied in the scope of the present invention. The term "(meth) acrylic acid" in the present specification is a concept encompassing both "acrylic acid" and "methacrylic acid". The term "(meth) acrylate" is a concept encompassing both "acrylate" and "methacrylate". The term "(meth) acryloyl" is a concept encompassing both "acryloyl" and "methacryloyl".

In the present specification, the light diffusing particle (A) is abbreviated as the "component (A)", the dispersing medium (B) as the "component (B)" and the radical scavenger May be used.

1. Composition for a light guide plate

The composition for a light guide plate (hereinafter simply referred to as " composition ") according to the present embodiment is a composition used for forming a light diffusion portion of a light guide plate. The composition for a light guide plate according to the present embodiment contains light diffusion particles (A) and a dispersion medium (B).

The cured film having a thickness of 10 mu m produced using the composition for a light guide plate according to the present embodiment has a reflectance of 0 to 50% at a wavelength of 300 to 380 nm and a reflectance of 30 to 99% at a wavelength of 400 to 800 nm, to be. That is, it has been found that the cured film contains the light diffusing particles (A) to be described later, so that it is easy to absorb ultraviolet light and is easily reflected by visible light.

When the reflectance at the wavelength of 300 to 380 nm of the cured film is within the above range, the curing property of the cured film tends to be good because ultraviolet light is easily absorbed when the dispersing medium (B) contains a photopolymerizable component. On the other hand, when the reflectance of the cured film at a wavelength of 400 to 800 nm is within the above range, the visible light is likely to be uniformly reflected, and the non-uniformity of brightness and chromaticity due to reflected light can be effectively suppressed. Therefore, according to the composition for a light guide plate according to the present embodiment, it is possible to manufacture a light guide plate having excellent homogeneity of surface emission and exhibiting good light emission characteristics.

The above-mentioned cured film having a thickness of 10 mu m can be manufactured in accordance with the method described in the following embodiments. The reflectance at a wavelength of 300 to 380 nm and the reflectance at a wavelength of 400 to 800 nm are measured by using a spectrophotometer for a cured film having a thickness of 10 占 퐉 obtained as described in Examples to be described later Can be obtained from the reflection spectrum.

Hereinafter, the components that can be included in the composition for a light guide plate according to the present embodiment will be described in detail.

1.1. The light-diffusing particles (A)

As the light-diffusing particles (A), inorganic particles or organic particles can be used. As the inorganic particles, calcium carbonate particles, barium sulfate particles, titanium dioxide particles and the like can be preferably used. As the organic particles, core-shell-type organic particles, hollow-phase organic particles, and non-spherical-shaped releasing organic particles can be preferably used. The light-diffusing particles (A) used in the present invention may be used singly or in combination of two or more kinds.

The number average particle diameter (Dn) of the light-diffusing particles (A) is preferably 0.3 to 2 mu m, more preferably 0.4 to 1.8 mu m, when the light-diffusing particles (A) are organic particles. On the other hand, when the light-diffusing particle (A) is an inorganic particle, it is preferably 0.5 to 3 mu m, more preferably 0.8 to 2.8 mu m. The number average particle diameter (Dn) of the light-diffusing particles (A) can be measured by using a particle size distribution measuring apparatus using the dynamic light scattering method as a measurement principle.

The "number average particle size measured by the dynamic light scattering method" refers to a measurement of the fluctuation of the scattered light intensity by using a particle size distribution measuring apparatus using the dynamic light scattering method as a measurement principle, obtaining an autocorrelation function by photon correlation, Average particle diameter obtained by applying the cumulant method and the histogram method.

As a particle size distribution measuring apparatus using the dynamic light scattering method as a measurement principle, there are a DensaNano S nanoparticle analyzer manufactured by Beckman Coulter, a Zetasizer nano zs manufactured by Malvern, an ELSZ manufactured by Otsuka Denshi Co., -1000ZS "

The inorganic particles having a number average particle diameter (Dn) falling within the above range can be obtained by appropriately selecting them based on the particle size distribution from a commercial product. The core shell particles, the hollow particles, the release particles, and the like can be produced by the method described in International Publication No. 2005/071014 or Japanese Patent Laid-Open Publication No. 2013-93205.

The coefficient of variation (CV value) of the particles of the light-diffusing particles (A) contained in the composition for a light guide plate according to the present embodiment is preferably in the range of 0.01 to 0.2, and more preferably in the range of 0.02 to 0.15. In the light guide plate, it is necessary to uniformly diffuse the light to the light emitting surface side. However, if the particle variation coefficient of the light diffusing particle (A) is within the above range, the degree of distribution of the particle diameter produces a state in which light can be uniformly diffused , It was found that the diffuse reflection of light can be reduced. As a result, the light extraction efficiency of the light guide plate is remarkably improved.

The particle variation coefficient (CV value) can be obtained by the following formula (1).

CV value = standard deviation of particle size distribution (?) / Number average particle diameter (Dn) ... (One)

The ratio (Rmax / Rmin) of the major axis Rmax and the minor axis Rmin in the light-diffusing particles A is preferably in the range of 1.01 to 1.2, more preferably in the range of 1.02 to 1.15. When the ratio Rmax / Rmin is within the above range, the surface area of the light-diffusing particles A is increased and the surface of the light-diffusing particles A is not a true spherical surface, And the average brightness of the light guide plate increases.

The long diameter (Rmax) of the light-diffusing particle (A) refers to the distance of the longest straight line among the straight lines connecting the end and the end of the image with respect to an image of one independent light diffusing particle photographed by a transmission electron microscope I mean it. The short radius (Rmin) of the light-diffusing particle (A) means the distance of the shortest straight line among the straight lines connecting the end and the end of the image with respect to the image of one independent light diffusing particle photographed by the transmission electron microscope do.

For example, as shown in Fig. 3, when the phase of one independent light diffusing particle 40a photographed by a transmission electron microscope is elliptical, the major axis a of the elliptical shape is set to the long diameter Rmax of the light diffusing particles And the short axis b is determined as the short diameter (Rmin) of the light-diffusing particles. As shown in Fig. 4, when an image of one independent light diffusing particle 40b photographed by a transmission electron microscope is an aggregate of two primary particles, the longest distance c among the straight lines connecting the end and the end of the image (Rmax) of the light-diffusing particles, and the shortest diameter d of the straight line connecting the ends of the image is determined as the short-axis diameter (Rmin) of the light-diffusing particles. As shown in Fig. 5, when an image of one independent light diffusing particle 40c photographed by a transmission electron microscope is an aggregate of three or more primary particles, the longest distance e Is determined as the long diameter (Rmax) of the light-diffusing particles, and the shortest diameter f of the straight line connecting the end and the end of the image is determined as the short diameter (Rmin) of the light-

The long diameter Rmax and the short diameter Rmin of 20 light diffusing particles A are measured and the average value of the long diameter Rmax and the short diameter Rmin is calculated by the above determination method, (Rmax / Rmin) of the average value of the long and short diameters to the average value of the short diameters.

The light-diffusing particle (A) may be, for example, a "release particle" such that the first light-diffusing particle and the second light-diffusing particle closely contact each other. In this case, the light-diffusing particle (A) may be a structure in which the other light-diffusing particle (A) is disposed on at least a part of the surface of one of the light-diffusing particles (A). Here, the term " release " in this specification means that two particles are arranged asymmetrically with respect to the center point of the whole particles.

Figs. 6 to 11 are explanatory diagrams schematically showing the concept of the release particle. Examples of the " releasable particles " include the structures shown in Figs. 6 to 11.

6, the second light diffusing particles 54a adhere closely to a part of the surface of the first light diffusing particle 52a, and the second light diffusing particle 54a is in contact with a part of the surface of the first light diffusing particle 52a, And protrudes from the surface of the particle 52a.

The modified particles 50b shown in Fig. 7 are formed such that the second light diffusion particles 54b are completely contained in the first light diffusion particles 52b, And is in contact with the second light-diffusing particles 54b, and has a generally spherical structure as a whole.

8, the first light-diffusing particles 52c and the second light-diffusing particles 54c adhere closely to each other and have a generally spherical structure as a whole. 8, the first light-diffusing particles 52c and the second light-diffusing particles 54c have the same surface area, but this point is particularly limited no.

9 includes second light diffusing particles 54d inside the first light diffusing particles 52d and the curved surface of the second light diffusing particles 54d is composed of the release particles 50d, And has a substantially spherical structure as a whole.

The deformed particle 50e shown in Fig. 10 has an elliptical spherical structure such as a rugby ball as a whole, with the variant particle 50c shown in Fig. In the modified particles 50e shown in Fig. 10, the first light-diffusing particles 52e and the second light-diffusing particles 54e have the same surface area, but this point is not particularly limited.

In the modified particles 50f shown in Fig. 11, the substantially spherical first light-diffusing particles 52f and the substantially spherical second light-diffusing particles 54f come in close contact with each other, and as a whole, .

When the releasable particles are organic particles, it is preferable that they are composed of two particles of the first light-diffusing particles and the second light-diffusing particles, though not particularly limited. In such a case, the composition of the first light-diffusing particles and the composition of the second light-diffusing particles may be the same or different. However, at least one of the monomer units included in the first light- Unit is preferable. That is, in this case, at least one of the monomer units constituting the releasing organic particles is included in only one of the first light diffusion particles and the second light diffusion particles. Thus, as shown in Figs. 6 to 11, the first light-diffusing particles and the second light-diffusing particles can be separated asymmetrically.

When the light-diffusing particle (A) is a release-type particle, the long-diameter and the short-diameter of the release-type particle are measured as follows in that the release-type particle constitutes substantially one particle. For example, when the light-diffusing particles A are substantially spherical particles 50a having spherical protrusions shown in Fig. 6, the long diameter Rmax is a distance from the end of the first light- And the distance to the end of the particle 54a. The minor axis Rmin is represented by the diameter of the larger particle (the first light-diffusing particle 52a in Fig. 6).

When the light-diffusing particle (A) is a release-type particle and the release-type particle is an organic particle, it can be produced by the method described in, for example, Japanese Laid-Open Patent Publication No. 2013-098123. When the releasable particles are inorganic particles, they can be suitably prepared by a known method such as a pulverization method and a classification operation after pulverization.

The absolute value of the refractive index difference |? N | between the light-diffusing particle (A) and the photopolymerizable component after polymerization is preferably 0.02? |? N |? 1.3. For example, when a photopolymerizable monomer or a photopolymerizable oligomer is used as the photopolymerizable component, calcium carbonate particles (refractive index: n = 1.59) and barium sulfate particles (refractive index: n = 1.64 ) And titanium dioxide particles (refractive index: n = 2.7) are used, the above conditions are satisfied.

In the composition for a light guide plate according to the present embodiment, the above-mentioned light-diffusing particles (A) are dispersed in the dispersion medium (B). When the light-diffusing particle (A) is an inorganic particle, the content of the light-diffusing particle (A) in the composition for a light guide plate according to the present embodiment is preferably 0.5 to 20 By mass, more preferably from 1 to 15% by mass, and particularly preferably from 3 to 12% by mass. When the light-diffusing particles (A) are organic particles, the amount is preferably 0.5 to 40% by mass, more preferably 5 to 35% by mass, and particularly preferably 5 to 50% by mass when the total mass of the composition is 100% 10 to 30 mass%. When the content of the light-diffusing particles (A) is in the above range, the storage stability of the composition becomes good and the coating property of the composition becomes good, so that a homogeneous light diffusing portion is likely to be formed on the surface of the light-

1.2. The dispersion medium (B)

The composition for a light guide plate according to the present embodiment contains a dispersion medium (B). When a light diffusing portion is manufactured using a composition for a light curing type light guide plate, it is preferable to use a photopolymerizable component as the dispersion medium (B). By using the photopolymerizable component, the generation of voids in the light diffusion portion described later can be suppressed, and the diffuse reflection caused by the generation of voids can be further suppressed. Such a photopolymerizable component preferably has a photopolymerizable functional group such as a vinyl group, and it is preferable to use a photopolymerizable monomer or a photosensitive polymer. As such a component, for example, the compound described in International Publication No. 2005/071014 or Japanese Patent Laid-Open Publication No. 2013-93205 can be timely used.

As the photopolymerizable monomer, for example, aromatic vinyl, unsaturated nitrile, unsaturated carboxylic acid ester, unsaturated amide and the like can be used.

Examples of the aromatic vinyls include styrene,? -Methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p- , m-divinylbenzene, p-divinylbenzene, m-diisopropenylbenzene, p-diisopropenylbenzene, o-chlorostyrene, m-chlorostyrene, p- Ethylene, p-methoxystyrene, N, N-dimethyl-p-aminostyrene, N, N-diethyl-p-aminostyrene, 2-vinylpyridine, 3-vinylpyridine and 4-vinylpyridine .

Examples of the unsaturated nitrile include (meth) acrylonitrile,? -Chloroacrylonitrile,? -Chloromethylacrylonitrile,? -Methoxyacrylonitrile,? -Ethoxyacrylonitrile, crotonic acid nitrile, Nitrile, nitrile, itaconic acid dinitrile, maleic acid dinitrile, and fumaric acid dinitrile.

Examples of the unsaturated carboxylic acid ester include (meth) acrylic acid esters; Crotonic acid esters such as methyl crotonate, ethyl crotonate, propyl crotonate and butyl crotonate; And cinnamic acid esters such as methyl cinnamate, ethyl cinnamate, propyl cinnamate, and butyl cinnamate. Among these, (meth) acrylic acid esters are preferable.

Examples of the (meth) acrylic esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, sec-butyl (Meth) acrylate, stearyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2- ethoxyethyl (Meth) acrylate;

(Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl Methyl) cyclohexyl] methyl (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate; (Meth) acrylic acid monoesters of polyalkylene glycols such as polyethylene glycol and polypropylene glycol;

Cyano group-containing (meth) acrylic acid esters such as cyanoethyl (meth) acrylate and cyanopropyl (meth) acrylate; (Meth) acrylic acid aryloxyalkyl esters such as 2-phenoxyethyl (meth) acrylate, 2-phenoxypropyl (meth) acrylate and 3-phenoxypropyl (meth) acrylate;

(Meth) acrylic acid monoesters of alkoxypolyalkylene glycols such as methoxypolyethylene glycol, ethoxypolyethylene glycol, methoxypolypropylene glycol and ethoxypolypropylene glycol; (Meth) acrylic acid monoesters of aryloxypolyalkylene glycols such as phenoxypolyethylene glycol and phenoxypolypropylene glycol; (Meth) acrylic acid diesters of alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and neopentyl glycol;

(Meth) acrylic acid diesters of polyalkylene glycols (the number of alkylene glycol units is, for example, 2 to 23) such as polyethylene glycol and polypropylene glycol, both terminal hydroxypolybutadiene, both terminal hydroxypolyisoprene, (Meth) acrylic acid diester of a polymer having hydroxyl groups at both terminals such as hydroxybutadiene-acrylonitrile copolymer and both terminal hydroxy polycaprolactone;

Glycerin, 1,2,4-butanetriol, trimethylolalkane (the number of carbon atoms of the alkane is, for example, 1 to 3), tetramethylolalkane (the number of carbon atoms of the alkane is, for example, 1 to 3), pentaerythritol (Meth) acrylic acid oligoesters such as (meth) acrylic acid diesters of trihydric or higher polyhydric alcohols, (meth) acrylic acid triesters or (meth) acrylic acid tetraesters;

(Meth) acrylic acid oligoester such as (meth) acrylic acid triester or (meth) acrylic acid tetraester of polyalkylene glycol adduct of polyvalent alcohol having three or more valences; And the like.

Examples of the unsaturated amide include unsaturated amides such as (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N- (2-hydroxyethyl) (Meth) acrylamide, N, N'-methylenebis (meth) acrylamide, N, N'-ethylenebis Morpholine, crotonic acid amide, cinnamic acid amide and the like.

As the photosensitive polymer, any known one can be used as long as the polymer skeleton has a photopolymerizable group introduced therein. Examples of such a polymer skeleton include a polyether skeleton, a polyurethane skeleton, a polyethylene skeleton, a polyester skeleton, a polyamide skeleton, a polyimide skeleton, and a polyphenylene skeleton, and preferably a polyether skeleton and a polyurethane skeleton . Examples of the photopolymerizable group include (meth) acryloyl groups, alkenyl groups, cinnamoyl groups, cinnamylidene acetyl groups, benzalacetophenone groups, styrylpyridine groups,? -Phenylmaleimide groups, A sulfonyl group, a sulfonyl group, a sulfonyl group, a sulfonyl group, a sulfonyl group, a sulfonyl group, a sulfonyl group, a sulfonyl group, a carbonyl group, a sulfonyl group, (Meth) acryloyl group and a cinnamoyl group, and particularly preferably a (meth) acryloyl group and a cinnamoyl group, Is a (meth) acryloyl group.

Further, by adding an aliphatic urethane (meth) acrylate as the dispersion medium (B), the viscosity and photo-curability of the composition for a light guide plate can be easily controlled.

The dispersion medium (B) used in the present invention may be used singly or in combination of two or more.

When the dispersion medium (B) contains a photopolymerizable component, the content of the photopolymerizable component in the composition for a light guide plate according to the present embodiment is preferably 50 to 95% By mass, more preferably 60 to 80% by mass. When the content of the photopolymerizable component is within the above range, the light diffusion particles (A) contained in the light diffusion portion formed on the surface of the light guiding substrate can be stored and maintained with sufficient strength, and the light diffusion particles It is possible to effectively suppress the occurrence of foreign matter such as peeling.

1.3. Radical scavenger (C)

The composition for a light guide plate according to the present embodiment may contain a radical scavenger (C). By containing the radical scavenger (C), it is possible to effectively prevent the polymerization of the photopolymerizable component in the storage step of the composition for the light guide plate and to suppress the unevenness of brightness and chromaticity of the light diffusion portion, Can be improved.

When the content of the light diffusing particles (A) in the composition is represented by Ma mass part and the content of the radical scavenger (C) is represented by Mc mass part, the ratio Ma / Mc of both is preferably 20 to 500, more preferably 30 ~ 300. By using the radical scavenger (C) within the above range, it is possible to effectively prevent the polymerization of the photopolymerizable component in the storage step of the composition for a light guide plate and to suppress the brightness unevenness and chromaticity unevenness of the light diffusion portion, It has been found that the homogeneity of luminescence is further improved.

The mechanism for exhibiting the effect of suppressing uneven brightness and chromaticity unevenness of the light diffusing portion and further improving the homogeneity of surface light emission of the light guide plate by containing the radical scavenger (C) is not clear, but is considered as follows.

In the use of the composition for a light guide plate, the composition for a light guide plate is always exposed to the outside air containing oxygen. For example, when the light diffusion portion is manufactured by printing, a certain time is required from the start to the end of printing on the light guiding substrate. Thereafter, a curing step such as light irradiation is performed on the printed light guide plate composition, and a light diffusion portion is produced. At this time, the light diffusing section bulb portion (referred to as a light-projecting portion composition printing portion before being cured and made into a light diffusing portion) fabricated at the beginning of printing is exposed to the atmosphere for a long time before the light diffusion portion bulb portion at the end of printing. It is considered that there is a difference in the amount of oxygen absorbed from the air in the light diffusing portion front portion due to the difference in the exposure time of this atmosphere. As a result, it is presumed that any change occurs in the cured state of the composition for a light guide plate in the subsequent curing step. It is presumed that the difference in the cured state becomes a difference in the light diffusion state of each light diffusion portion, thereby promoting deterioration of the homogeneity of the surface light emission of the light guide plate.

However, when the composition for the light guide plate contains the radical scavenger (C), there is a difference in the amount of oxygen absorbed from the atmosphere during this atmospheric exposure time. As a result, Even if there is a difference in the amount of oxygen contained in the diffuser portion and in the subsequent curing process, even if there is a difference in the amount of oxygen radicals generated from the absorbed oxygen, the radical scavenger (C) . As a result, it is possible to cure the bulb portion of the light diffusing portion having a more homogeneous composition, and it is presumed that the homogeneity of the surface emission of the light guide plate can be further improved.

As the radical scavenger (C), for example, a phenol derivative is preferable. By using a phenol derivative, whiteness of the light diffusion portion is further improved. Examples of the phenol derivative include hydroquinone, hydroquinone monomethyl ether, mono-tert-butyl hydroquinone, catechol, 4-tert-butylcatechol, p- methoxyphenol, 2,5- Hydroxyquinone, 2,6-di-tert-butyl-m-cresol, pyrogallol, and? -Naphthol, benzoquinone, 2,5-diphenyl- p-xyloquinone, and the like. The radical scavenger (C) used in the present invention may be used singly or in combination of two or more.

The content of the phenol derivative as the radical scavenger (C) in the composition for a light guide plate according to the present embodiment is preferably 0.001 to 2% by mass, more preferably 0.01 to 1% by mass, based on 100% by mass of the total mass of the composition. By mass, particularly preferably 0.05 to 0.5% by mass. When the content of the phenol derivative as the radical scavenger (C) is within the above range, polymerization of the photopolymerizable component in the storage step of the composition for a light guide plate can be effectively prevented. Further, the whiteness of the light diffusion portion can be further improved.

1.4. Photopolymerization initiator

The composition for a light guide plate according to the present embodiment may contain a photopolymerization initiator. In particular, when the dispersion medium (B) is a photopolymerizable component, it is preferable that the dispersion medium (B) contains a photopolymerization initiator in order to enhance the photocurability.

Such a photopolymerization initiator may be appropriately selected from those conventionally used in the field of the radiation curable resin, and examples thereof include compounds described in International Publication No. 2005/071014 and Japanese Patent Laid-Open Publication No. 2013-93205 have.

Specific examples of the photopolymerization initiator include? -Diketone compounds such as diacetyl, methylbenzoylformate and benzyl; Benzoin, pivaloin and the like; Acyloin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutyl ether; Polynuclear quinones such as anthraquinone, 2-ethyl anthraquinone, 2-tert-butyl anthraquinone, and 1,4-naphthoquinone; Acetophenone such as acetophenone, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexylphenylketone, 2,2-dimethoxyphenylacetophenone, 2,2-diethoxyacetophenone and trichloroacetophenone Phenones; Benzophenones such as benzophenone, methyl-o-benzoyl benzoate and Michler's ketone; And xanthones such as xanthone, thioxanthone and 2-chlorothioxanthone. The photopolymerization initiators used in the present invention may be used singly or in combination of two or more.

The content of the photopolymerization initiator in the composition for a light guide plate according to the present embodiment is preferably 0.1 to 20 mass%, more preferably 0.5 to 10 mass%, based on 100 mass% of the total mass of the composition. When the content of the photopolymerization initiator is within the above range, the light curing property of the composition for a light guide plate is improved, so that a tack free light diffusing portion can be produced.

1.5. Other components

The composition for a light guide plate according to the present embodiment may contain components other than the above components, such as an isothiazoline compound, a phosphoric acid ester, a surfactant, water, a binder and the like.

≪ Isothiazoline compound >

By adding the isothiazoline compound to the composition for a light guide plate according to the present embodiment, the isothiazoline compound acts as a preservative to inhibit the generation of foreign matter due to the growth of bacteria and fungi when the composition for a light guide plate is stored can do. It has also been found that the uniformity of the surface emission of the light guide plate can be further improved by suppressing unevenness in brightness and chromaticity of the light diffusion portion.

Although the mechanism for exhibiting the effect of suppressing uneven brightness and chromaticity unevenness of the light diffusing portion and further improving homogeneity of surface light emission of the light guide plate by containing an isothiazoline based compound is not clear, it is considered as follows. In the use of the composition for a light guide plate, the composition for a light guide plate is always exposed to the outside air containing oxygen. For example, when the light diffusion portion is manufactured by printing, a certain time is required from the start to the end of printing on the light-guiding substrate. Thereafter, a curing step such as light irradiation is performed on the printed light guide plate composition, and a light diffusion portion is produced. At this time, the light diffusing section bulb portion (referred to as a light-projecting portion composition printing portion before being cured and made into a light diffusing portion) fabricated at the beginning of printing is exposed to the atmosphere for a long time before the light diffusion portion bulb portion at the end of printing. It is considered that there is a difference in the amount of volatile organic compounds absorbed from the air in the light diffusing portion front portion due to the difference in the exposure time of the atmosphere. As a result, any change occurs in the cured state of the composition for the light guide plate in the subsequent curing step, and the difference in the cured state becomes a difference in the light diffusion state of each light diffusion portion, thereby promoting deterioration of homogeneity of surface light emission of the light guide plate .

On the other hand, in the composition for a light guide plate according to the present embodiment, the isothiazoline compound tends to be retained and retained by being adsorbed on the light diffusing particles (A). As a result, it is considered that the surface of the light-diffusing particle (A) is protected by the isothiazoline compound, and the above-mentioned volatile organic substance absorbed from the atmosphere can be inhibited from adsorbing to the surface of the light-diffusing particle (A). As a result, even when there is a difference in the amount of volatile organic compounds contained in the light diffusing portion precursors in the initial stage of manufacturing and the production of the light diffusing portion bulb, these volatile organic substances are not strongly adsorbed on the surface of the light diffusing particles (A). By this action, the light diffusion portion of the light diffusion portion having a more homogeneous composition can be cured because it is released into the air again without being stored and held in the light diffusion portion in the subsequent curing step, thereby further improving the homogeneity of surface light emission of the light guide plate I think it was possible.

The isothiazoline compound is not particularly limited as long as it is a compound having an isothiazoline skeleton, and examples thereof include a compound represented by the following formula (2) and a compound represented by the following formula (3).

In the general formula (2), R ¹ is a hydrogen atom or a hydrocarbon group, and R ² and R ³ each independently represent a hydrogen atom, a halogen atom or a hydrocarbon group. When R ¹ , R ² and R ³ are hydrocarbon groups, they may have a straight chain carbon skeleton such as a straight chain or a branched chain, or may have a cyclic carbon skeleton. The number of carbon atoms of the hydrocarbon group is preferably 1 to 12, more preferably 1 to 10, and particularly preferably 1 to 8. Specific examples of such hydrocarbon groups include methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, octyl and 2-ethylhexyl groups.

In the general formula (3), R ⁴ is a hydrogen atom or a hydrocarbon group, and each R ⁵ independently represents a hydrogen atom or an organic group. When R ⁴ is a hydrocarbon group, the same hydrocarbon group as the hydrocarbon group described in the general formula (2) can be mentioned. When R ⁵ is an organic group, the organic group includes an aliphatic group or an aromatic group which is an alkyl group or a cycloalkyl group, but is preferably an aliphatic group. The alkyl group preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, and particularly preferably 1 to 8 carbon atoms. These alkyl and cycloalkyl groups may have substituents such as a halogen atom, an alkoxyl group, a dialkylamino group, an acyl group, and an alkoxycarbonyl group. Specific examples of the aliphatic group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a hexyl group, a cyclohexyl group, an octyl group and a 2-ethylhexyl group. In the formula (3), n represents an integer of 0 to 4.

Specific examples of the isothiazoline compounds include 1,2-benzoisothiazolin-3-one, 2-methyl-4,5-trimethylene-4-isothiazolin- 2-methyl-4-isothiazolin-3-one, Nn-butyl-1,2-benzisothiazolin- 2-n-octyl-4-isothiazolin-3-one, and 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one. Among these, one type or two or more types can be used. Of these, 2-methyl-4-isothiazolin-3-one, 2-n-octyl-4-isothiazolin- , 1,2-benzoisothiazolin-3-one are preferred.

The content of the isothiazoline compound in the composition for a light guide plate according to the present embodiment is preferably 0.01 to 0.5% by mass, more preferably 0.015 to 0.2% by mass, more preferably 0.01 to 0.5% by mass, Preferably 0.015 to 0.1% by mass. By using the isothiazoline compound within the above range, the storage stability of the composition for a light guide plate can be improved.

When the content of the light-diffusing particles (A) in the composition is represented by Ma mass part and the content of the isothiazoline based compound is represented by Md mass part, it is preferable that the ratio is such that the ratio Ma / Md is 50 to 600, More preferably 100 to 500. It has been found that by using the isothiazoline compound in the above-mentioned range, the storage stability of the composition for a light guide plate is improved and the unevenness of brightness and chromaticity of the light diffusing portion are suppressed to further improve the homogeneity of surface light emission of the light guide plate.

<Phosphoric ester>

By adding phosphoric acid ester to the composition for a light guide plate according to the present embodiment, adhesion between the light-guiding substrate and the light diffusion portion can be enhanced. It is also possible to improve the balance of hardness, scratch resistance, abrasion resistance and low curl when the composition for a light guide plate is used as a cured coating film.

The phosphoric acid ester is preferably a compound represented by the following general formula (4). Even in the case where the phosphate ester corresponds to the photopolymerizable component, in the present invention, the phosphate ester and the dispersion medium (B) are treated as different components.

(In the formula (4), R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents a divalent organic group, and n represents an integer of 1 or 2)

Examples of the phosphoric acid esters include mono- or bis (2- (meth) acryloyloxyethyl) phosphate esters, mono- or bis (2- (meth) acryloyloxypropyl) phosphate esters, mono- or bis (Meth) acryloyloxypropyl) phosphoric acid ester, mono or bis (6- (meth) acryloyloxyhexyl) phosphate ester, mono or bis (Meth) acryloyloxyethylphenylphosphoric acid ester, and lactone-modified products thereof, polyoxyalkylene-modified products thereof, and the like. . Of these, mono or bis (2- (meth) acryloyloxyethyl) phosphate esters are preferable from the viewpoint of obtaining a light diffusion portion excellent in adhesion to a light-guiding substrate and hardness. The phosphate esters used in the present invention may be used singly or in combination of two or more.

Examples of commercial products of phosphoric acid esters include commercially available products such as KYAMER PM-2 and PM-21 manufactured by Kyoeisha Kagaku Kogyo K.K. under the trade names of Wrightester P-1M, P-2M and Nippon Kayaku Co., .

The content of the phosphoric acid ester in the composition for a light guide plate according to the present embodiment is preferably 0.07 to 5 mass%, more preferably 0.2 to 2 mass%, based on 100 mass% of the total mass of the composition.

<Surfactant>

By adding a surfactant to the composition for a light guide plate according to the present embodiment, the surface tension of the composition for a light guide plate and the wettability of the light guide substrate can be controlled. The surfactant is not particularly limited, but silicone surfactants and fluorine surfactants are preferred.

The content of the surfactant in the composition for a light guide plate according to the present embodiment is preferably 0.01 to 2% by mass, more preferably 0.05 to 1% by mass, based on 100% by mass of the total mass of the composition.

<Water>

By adding water to the composition for a light guide plate according to the present embodiment, the storage stability of the composition for a light guide plate may be improved.

The content of water in the composition for a light guide plate according to this embodiment is preferably 0.5% by mass or less, more preferably 0.01 to 0.4% by mass, based on 100% by mass of the total mass of the composition.

In addition, since the inorganic particles generally have a large surface area and the surface is hydrophilic, the inorganic particles tend to adsorb moisture. On the other hand, since the surface area of the organic particles is smaller than that of the inorganic particles and the surface is hydrophobic, moisture adsorption can be suppressed. therefore. In order to strictly control the water content in the composition for a light guide plate, the light-diffusing particles (A) are preferably organic particles.

<Binder>

By adding a binder to the composition for a light guide plate according to the present embodiment, the adhesion between the light-guiding substrate and the light diffusion portion can be improved. The binder is not particularly limited, but a binder described in International Publication No. 2005/071014 or Japanese Patent Laid-Open Publication No. 2013-93205 can be used.

2. Light guide plate

The light guide plate according to the present embodiment is characterized by being manufactured using the above-mentioned composition for a light guide plate. Specifically, the above-described composition for a light guide plate is applied or printed on a light guide substrate having a surface roughness Ra <1 nm to prepare a light diffusion portion.

1 is a cross-sectional view showing a transmissive image display apparatus including a light guide plate according to an embodiment of the present invention. The transmission type image display apparatus 100 shown in Fig. 1 is mainly composed of a surface light source device 20 and a transmission type image display section 30. Fig. The planar light source device 20 includes a light guide plate 1 having a light guide plate 11 and a light diffusion portion 12 and a light source (not shown) provided on the side of the light guide plate 1 and supplying light to the light guide plate 1 3). &Lt; / RTI &gt; In Fig. 1, the light diffusion portion 12 has a plurality of dot shapes.

The light-guiding substrate 11 has a substantially rectangular parallelepiped shape and includes an emission surface S1 and an emission surface S2 on the opposite side of the emission surface S1 and four emission surfaces S1 and S2 intersecting the emission surface S1 and emission surface S2. (S3 _{1 to} S3 ₄ ). In the present embodiment, the four end faces S3 _{1 to} S3 ₄ are substantially orthogonal to the exit face S1 and the exit face S2.

The light guide plate 1 has a plurality of light diffusion portions 12 formed on the light exit surface S2 side. As shown in Fig. 2, the plurality of light diffusing portions 12 are arranged on the emission surface S2 at a distance from each other. Fig. 2 is a plan view of the light guiding plate viewed from the emission surface S2 side. Fig. 2, the light source 3 is also shown for convenience of explanation. In Fig. 2, the light diffusion portions 12 are disposed apart from each other. The number and arrangement pattern of the light diffusion portions 12 are adjusted so that light of a uniform surface shape is efficiently emitted from the emission surface S1 and, if necessary, from the emission surface S2.

As shown in Figs. 1 and 2, the light source 3 is disposed on the side of a pair of end faces S3 ₁ and S3 ₂ facing each other. As shown in Fig. 2, a plurality of point-shaped light sources may be arranged along two mutually opposing sides of four sides constituting a rectangular emitting surface S2 of the light-guiding substrate 11. [

In the above configuration, the light output from the light source 3 is incident on the light-guiding substrate 11 from the end faces S3 ₁ and S3 ₂ . The light incident on the light guide substrate 11 is diffusely reflected by the light diffusing portion 12 so that light of a uniform surface shape is efficiently emitted from the emission surface S1 and the emission surface S2, 12 can be adjusted. For example, in the case of Fig. 1, the light emitted from the emitting surface S1 is supplied to the transmissive-type image display section 30. Fig.

Hereinafter, the members constituting the light guide plate and the manufacturing method of the light guide plate will be described in detail.

2.1. Light-

The light guide plate 1 is provided with a light guide substrate 11. The surface roughness Ra of the light-guiding substrate 11 is preferably Ra <1 nm and Ra <0.5 nm in consideration of the light extraction efficiency from the emission surface S1 and the emission surface S2. In consideration of the adhesion between the light diffusing portion and a light-guiding substrate, which will be described later, Ra> 0.1 nm is preferable, and Ra> 0.2 nm is more preferable.

The surface roughness Ra of the cross section of the light guiding substrate 11 is set such that light of a practically usable degree can be emitted from the light source to the inside of the light guiding substrate 11 if the light from the light source suppresses scattering on the cross- As shown in FIG.

The "surface roughness Ra" of the light-guiding substrate 11 in the present invention means "arithmetic mean roughness" measured in accordance with JIS B0601-2001.

Generally, in the edge light type surface light emitting device, when light is generated from the light source, heat is generated, and the temperature of the light guiding substrate rises accordingly. In the case of using a resin plate as the light-guiding substrate, since the thermal expansion coefficient of the resin plate is high, the dimensional change due to heat of the light-guiding substrate becomes larger than the dimensional change of the liquid crystal panel. However, due to narrow framing of the liquid crystal display device, it is difficult to correct the dimensional change of the light-guiding substrate at the edge portion of the liquid crystal display device. For this reason, as the material of the light-guiding substrate 11, a resin plate having a small dimensional change due to heat may be used, but a glass substrate is preferable. When the light-guiding substrate 11 is a glass substrate, the maximum transmittance of the glass substrate at an optical path length of 100 mm and a wavelength range of 350 to 750 nm is preferably 50% or more.

The thermal expansion coefficient of the glass substrate is preferably 120 x 10 &lt; ^-7 &gt; / DEG C or lower. If the coefficient of thermal expansion exceeds the above range, a difference in dimensional change due to heat between the display panel and the light guide substrate tends to increase. The glass substrate preferably has a strain point of 550 DEG C or higher. If the strain point is less than the above range, the heat resistance of the glass substrate tends to deteriorate. For example, when a reflective film, a diffusion film, or the like is formed on the surface of a glass substrate at high temperature, the glass substrate is likely to be thermally deformed. Here, the &quot; strain point &quot; can be measured based on JIS R3103.

2.1.1. Glass composition

As the glass composition constituting the glass substrate, and 40 to 70 mass% SiO _2, 2~25 wt% of Al ₂ O _3, 0~20% by weight of _{B 2 O 3, R 2 O} (R is Li, Na, 0 to 10 mass% of MgO, 0 to 15 mass% of CaO, 0 to 10 mass% of SrO, 0 to 15 mass% of BaO, 1 to 5 mass% of ZnO, for 0 to 10% by weight, ZrO ₂ preferably contains 0 to 10% by weight.

SiO ₂ is a component that becomes a network former of glass, and is a component that decreases the thermal expansion coefficient and reduces the dimensional change due to heat. It is also a component that increases acid resistance and strain point. When the content of SiO ₂ is increased, the high-temperature viscosity is increased, the solubility is lowered, and the release of cristobalite is likely to occur at the time of molding. On the other hand, if the content of SiO ₂ is decreased, the coefficient of thermal expansion tends to increase, and the dimensional change due to heat tends to increase. Also, the acid resistance and the strain point are likely to decrease.

Al ₂ O ₃ is a component that reduces the coefficient of thermal expansion and reduces the dimensional change caused by heat. There is also an effect of increasing the strain point or suppressing the precipitation of cristobalite in molding. When the content of Al ₂ O ₃ is within the above range, the liquidus temperature rises and it becomes difficult to form the glass substrate. On the other hand, if the content of Al ₂ O ₃ is decreased, the coefficient of thermal expansion tends to increase, and the dimensional change due to heat tends to increase. And the strain point is also likely to deteriorate.

B ₂ O ₃ is a component that acts as a flux to lower the high-temperature viscosity and improve the solubility. It is also a component that reduces the thermal expansion coefficient and reduces the dimensional change due to heat. When the content of B ₂ O ₃ is within the above range, the dimensional change due to heat can be suppressed, and the solubility can be improved and the workability can be improved.

R ₂ O is a component that lowers the high-temperature viscosity and improves solubility. When the content of R ₂ O is within the above range, the strain point can be improved and the maximum transmittance near the wavelength of 550 nm can be improved.

MgO is a component that lowers only the high temperature viscosity without lowering the strain point and improves the solubility. When the content of MgO is within the above range, deposition of the siltite during molding can be suppressed.

CaO is a component that reduces solubility by lowering only the high-temperature viscosity without lowering the strain point. When the content of CaO is within the above range, precipitation of the siltite during molding can be suppressed.

SrO is a component that enhances chemical resistance and resistance to devitrification. When the content of SrO is within the above range, the thermal expansion coefficient is lowered and the dimensional change due to heat can be suppressed.

BaO is a component that enhances chemical resistance and resistance to devitrification in the same manner as SrO. When the content of BaO is within the above range, thermal expansion and thermal expansion can be suppressed, and the dimensional change due to heat can be suppressed.

ZnO is a component that improves solubility. When the content of ZnO is within the above range, resistance to devitrification can be improved.

ZrO ₂ is a component to increase the strain point. When the content of ZrO ₂ is within the above range, it is possible to suppress precipitation of the siltite during molding.

The content of transition metal oxides such as Fe ₂ O ₃ , Cr ₂ O ₃ , V ₂ O ₅ , NiO, MnO ₂ , Nd ₂ O ₃ , CeO ₂ and Er ₂ O ₃ is preferably 0.1 mass% or less. If the content of the transition metal oxide is excessively large, the light extraction efficiency may decrease.

In addition to the above components, other components may be introduced. For example, in order to lower the liquidus temperature, up to 3 mass% each of Y ₂ O ₃ , La ₂ O ₃ , Nb ₂ O ₅ and P ₂ O ₅ , As ₂ O ₃ , Sb ₂ O ₃ , SnO ₂ , SO ₃ , F, Cl, or the like may be introduced in an amount of up to 2% by mass.

2.1.2. Manufacturing method of glass substrate

The glass substrate can be manufactured by an overflow down-draw method, a slot-down draw method, a float method, a roll-out method, a lead-down method, or the like. Further, in the float method, the temperature difference and the composition difference of the front and back surfaces of the glass ribbon are likely to occur at the time of molding, but when the temperature control during molding is strictly performed, the temperature difference and the compositional difference can be reduced. In the overflow down-draw method, the temperature difference and the composition difference on the front and back surfaces of the glass ribbon are hard to occur at the time of molding, and the glass substrate having good surface quality due to the un-polishing is easily formed.

Further, the glass substrate may be applied to a glass substrate used for a display panel to perform the function of the light-guiding substrate. By doing so, the member configuration of the display device can be simplified.

2.2. The light-

The light guide plate 1 according to the present embodiment includes a light diffusing portion 12 containing light diffusing particles (A). The number average particle diameter Dn (nm) of the light-diffusing particles A is preferably in a relationship of 200 <Dn / Ra <5000 to the surface roughness Ra (nm) of the light-guiding substrate 11, &Lt; 4000 is more preferable. When the value of Dn / Ra is within the above range, mixing of voids in the interface between the light guide substrate 11 and the light diffusion portion 12 can be suppressed, and light extraction efficiency can be improved to realize homogeneous surface light emission do.

2 described above, the light diffusion portions 12 are arranged in a plurality of dot shapes having a substantially circular shape and are disposed apart from each other. However, the necessary light extraction efficiency from the timely exit surface S1 and the exit surface S2 is So that the shape and the like can be adjusted. The shape of the light diffusion portion 12 shown in Fig. 2 is for convenience of explanation, and can be adjusted in consideration of necessary light extraction efficiency from the emission surface S1 and the emission surface S2.

The light diffusion portion 12 is fabricated using the above-described composition for a light guide plate. The light diffusion portion 12 may be formed on the light guide substrate 11 by a screen printing method, an offset printing method, a spray coating method in which the composition for a light guide plate is sprayed from a nozzle, or the like. For example, the light guide plate can be manufactured by the method described in International Publication No. 2005/071014, Japanese Laid-Open Patent Publication No. 2013-93205, Japanese Laid-Open Patent Publication No. 2012-178345, and the like.

As the composition for the light guide plate, a thermosetting or photo-curable composition for a light guide plate is preferable. In order to effectively suppress the deformation of the light guide substrate by the heat treatment, it is more preferable to fabricate the light diffusion section by using the composition for the light guide plate. The composition for a light guide plate for forming the light diffusion portion 12 is preferably a composition for a radiation curable light guide plate containing a photopolymerizable component and a photopolymerization initiator in a photocurable composition for a light guide plate.

It is preferable that the area of the light diffusion portion 12 is 5% or more and 95% or less with respect to 100% of the area of the light guide substrate 11. [ The ratio of the plane area occupied by the light diffusion portion 12 on the coated surface of the light guide substrate 11 and the application area of the composition for the light guide plate or the application area of the composition for the light guide plate and the light guide plate It is preferable that the ratio of the coating area of the area of the coating surface of the coating layer 11 is increased. Thus, the brightness of the light guide plate can be made substantially uniform.

2.3. Light source

As shown in Figs. 1 and 2, the light source 3 is disposed on the side of the end face (S3 ₁ or S3 ₂ ). The light source 3 may be a linear light source such as a cold cathode fluorescent lamp (CCFL) or the like, but is preferably a point light source such as an LED. In this case, as shown in Fig. 2, a plurality of point-like light sources are arranged along two opposite sides of four sides constituting a rectangular exit surface S2 of the light guide plate 1, for example, It is preferable that the light source 12 and the light source 3 are combined.

In the above configuration, light output from the light source 3 enters the light guide plate 1 from the end face (S3 ₁ or S3 ₂ ). Light incident on the light guide plate 1 is diffused or diffused in the light diffusing portion 12 to be emitted from the exit surface S1 or S2. The light emitted from the emission surface S1 or S2 is supplied to the transmission type image display section 30 or the like. The number of the light diffusion portions 12 and the arrangement pattern can be adjusted in a timely manner so that light of a uniform surface shape is efficiently emitted from the emission surface.

2.4. The transmissive-type image display section

1, the transmissive-type image display section 30 is disposed opposite to the light guide plate 1 on the side of the light exit surface S1 of the light guide plate 1. Light emitted from the light exit surface S1 is transmitted through the transmissive- The display unit 30 is illuminated. As the transmissive-type image display section 30, for example, a liquid crystal display section having a liquid crystal cell or the like can be used.

3. Example

Hereinafter, the present invention will be described concretely with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, &quot; part &quot; and &quot;% &quot; are based on mass unless otherwise specified.

3.1. Production of light diffusing particles (A)

3.1.1. Fabrication of hollow particles 1

194 parts of water, 9 parts of methyl methacrylate, 1 part of methacrylic acid, 0.92 part of octyl thioglycolate as a molecular weight regulator, and 0.04 parts of sodium dodecylbenzenesulfonate as an emulsifier were fed into a 2 liter reaction vessel. Meanwhile, 71 parts of methyl methacrylate, 19 parts of methacrylic acid, 0.5 part of octyl thioglycolate, 0.5 part of sodium dodecylbenzenesulfonate and 45 parts of water were mixed and stirred to prepare an aqueous dispersion of monomer mixture.

The reaction vessel was heated to 85 캜 with stirring, and 6% aqueous 5% sodium persulfate solution was added as a polymerization initiator. Immediately thereafter, while the reaction vessel was maintained at a temperature of 90 ° C with stirring, the aqueous dispersion of the monomer mixture was continuously added over 4 hours. Further, aging was carried out for 2 hours to obtain an aqueous dispersion (solid content: 29.3%) of the seed particle A having a particle diameter of 0.200 mu m.

143 parts of water and 10 parts (34 parts as an aqueous dispersion) of an aqueous dispersion of the seed particles A as solid content and 1.2 parts of an 80% acrylic acid aqueous solution were added to a reaction vessel of 2 liters capacity. Meanwhile, 77.2 parts of styrene, 0.8 parts of divinylbenzene (m, p-mixture, purity 81%), 1.3 parts of 80% acrylic acid aqueous solution, 0.5 part of sodium dodecylbenzenesulfonate and 46.7 parts of water were mixed and stirred to prepare an aqueous To prepare a dispersion.

The reaction vessel was heated to 80 DEG C with stirring, and 8 parts of a 5% aqueous solution of sodium persulfate was added as a polymerization initiator. While maintaining the temperature of the reaction vessel at 80 占 폚 with stirring, the aqueous dispersion of the monomer mixture was continuously added over 2 hours. Immediately after all the aqueous dispersions of the monomers were put in the reaction vessel, 19.6 parts of styrene, 0.4 parts of divinylbenzene (m, p-mixture, purity 81%) and 20 parts of 6% ammonium hydroxide were added. Thereafter, the temperature was elevated to 85 캜 and aged for 2 hours to obtain an aqueous dispersion (spherical solid 30.9%) of spherical hollow seed particles B having a single pore with a particle diameter of 0.487 탆, pore diameter of 0.312 탆 and volume porosity of 26% ).

In a reaction vessel of 2 liters in capacity, 569 parts of water, 100 parts (324 parts as an aqueous dispersion) of an aqueous dispersion of the hollow seed particles B, 20 parts of styrene, 100 parts of divinylbenzene (m, %) And 4 parts of sodium dodecylbenzenesulfonate were added thereto. The reaction vessel was maintained at 40 DEG C for 3 hours with stirring, then heated to 65 DEG C, and 6 parts of a 5% aqueous solution of sodium persulfate as a polymerization initiator was added. Further, the reaction vessel was heated, and stirring was continued while maintaining 80 DEG C, and after 1 hour from reaching 80 DEG C, 2 parts of a 5% aqueous solution of sodium persulfate was added, and further stirring was continued for 1 hour. Thereafter, the temperature was raised to 85 캜, and after 1 hour, 2 parts of a 5% aqueous solution of sodium persulfate was added, and agitation was further performed for 1 hour. Thereafter, the reaction vessel was cooled to 40 占 폚, and the contents were filtered using a nylon mesh having a graduation interval of 50 占 퐉 and further subjected to pressure filtration using a cartridge filter made of polypropylene with a filtration accuracy of 10 占 퐉 to obtain hollow particles 1 (solid content: 20.5%) was obtained. The obtained aqueous dispersion was dried by a spray drying method (temperature 110 to 220 占 폚) using a Mini Spray Dryer B-290 manufactured by Nippon Beehisa Co., Ltd. to obtain a single dispersion having a particle diameter of 0.609 占 퐉, a pore diameter of 0.381 占 퐉, Spherical hollow particles 1 having pores of the spherical particles were obtained.

Further, the long diameter Rmax and the short diameter Rmin were measured for arbitrary 20 hollow particles 1 by a transmission electron microscope (type "H-7650" manufactured by Hitachi High-Technologies Corporation) As a result, the long diameter was 0.615 mu m, the short diameter was 0.604 mu m, and the ratio (Rmax / Rmin) of the long diameter to the short diameter was 1.02.

Using the thus obtained aqueous dispersion of the hollow particles 1 as a sample and using a particle size distribution measuring apparatus (type "ELSZ-1000ZS" manufactured by Otsuka Denshi Co., Ltd.) having a dynamic light scattering method as a measurement principle, The number average particle size (Dn) and the standard deviation (?) Of the particle size distribution of the hollow particles 1 were found to be 0.609 μm and the standard deviation (σ) was 0.034 μm. From these values, the coefficient of variation (CV value) of the particles was calculated by the following equation (1). As a result, the CV value was 0.056.

CV value = (standard deviation (?) Of particle size distribution / number average particle diameter (Dn)) ... (One)

3.1.2. Fabrication of Hollow Particles 2

In a reaction vessel of 2 liters in capacity, 569 parts of water, 100 parts (324 parts as a water dispersion) of the water dispersion of the hollow seed particles B, 20 parts of styrene, 100 parts of divinylbenzene (m, %) And 4 parts of sodium dodecylbenzenesulfonate were added thereto. The reaction vessel was maintained at 40 DEG C for 3 hours with stirring, then heated to 70 DEG C, and 6 parts of a 5% aqueous solution of sodium persulfate as a polymerization initiator was added. Stirring was continued while maintaining the temperature at 70 占 폚, and 3 hours after reaching 70 占 폚, 2 parts of a 5% aqueous solution of sodium persulfate was added, and agitation was further performed for 1 hour. Thereafter, the reaction vessel was cooled to 40 占 폚, and the contents were filtered using a nylon mesh having a graduation interval of 50 占 퐉 and further subjected to pressure filtration using a cartridge filter made of polypropylene with a filtration accuracy of 10 占 퐉 to obtain hollow particles 2 (solid content: 20.5%) was obtained. The obtained aqueous dispersion was dried by a spray drying method (temperature 110 to 220 占 폚) using a Mini Spray Dryer B-290 manufactured by Nippon Beehisa Co., Ltd. to obtain a single dispersion having a particle diameter of 0.560 占 퐉, a pore diameter of 0.260 占 퐉 and a volume porosity of 10% Spherical hollow particles 2 having pores of the spherical shape were obtained.

The long diameter (Rmax) and the short diameter (Rmin) of the hollow particles 2 were measured in the same manner as the hollow particles 1, and as a result, the long diameter was 0.587 mu m and the short diameter was 0.534 mu m. The number average particle size, standard deviation, and particle variation coefficient of the hollow particles 2 were determined in the same manner as the hollow particles 1. The number average particle size was 0.560 mu m, the standard deviation was 0.099 mu m, and the particle variation coefficient was 0.177.

3.1.3. Fabrication of Hollow Particles 3

143 parts of water and 10 parts (34 parts as an aqueous dispersion) of an aqueous dispersion of the seed particles A as solid content and 1.2 parts of an 80% acrylic acid aqueous solution were added to a reaction vessel of 2 liters capacity. On the other hand, 78 parts of styrene, 1.3 parts of 80% acrylic acid aqueous solution, 0.5 part of sodium dodecylbenzenesulfonate and 46.7 parts of water were mixed and stirred to prepare an aqueous dispersion of a monomer mixture.

The reaction vessel was heated to 80 DEG C with stirring, and 8 parts of a 5% aqueous solution of sodium persulfate was added as a polymerization initiator. While maintaining the temperature of the reaction vessel at 80 占 폚 with stirring, the aqueous dispersion of the monomer mixture was continuously added over 2 hours. 20 parts of divinylbenzene (m, p-mixture, purity 81%) and 20 parts of 6% ammonium hydroxide were added all at once immediately after the aqueous dispersions of the above monomers were all charged into the reaction vessel. Thereafter, the temperature was raised to 85 캜 and aged for 2 hours. Thereafter, the reaction vessel was cooled to 40 占 폚, and the contents were filtered using a nylon mesh having a graduation interval of 50 占 퐉 and further subjected to pressure filtration using a cartridge filter made of polypropylene with a filtration accuracy of 10 占 퐉 to obtain hollow particles 3 (solid content: 20.5%) was obtained. The aqueous dispersion thus obtained was dried by a spray drying method (temperature: 110 to 220 캜) using a Mini Spray Dryer B-290 manufactured by Nippon Beehisa KK to obtain a single dispersion having a particle diameter of 0.541 탆, a pore diameter of 0.427 탆, Spherical hollow particles 3 having pores of the spherical shape were obtained.

The long diameter (Rmax) and the short diameter (Rmin) of the hollow particles 3 were measured in the same manner as in the hollow particles 1, and as a result, the long diameter was 0.614 占 퐉, the short diameter was 0.469 占 퐉 and the ratio (Rmax / Rmin) The number average particle diameter, standard deviation, and particle variation coefficient of the hollow particles 3 were determined in the same manner as the hollow particles 1. The number average particle diameter was 0.541 mu m, the standard deviation was 0.162 mu m, and the particle variation coefficient was 0.299.

3.1.4. Fabrication of closed chamber particle 1

947 parts of water, 1.6 parts (5.5 parts by weight of an aqueous dispersion) of an aqueous dispersion of the seed particle A as a solid component and 0.5 part of sodium dodecylbenzenesulfonate were fed into a reaction vessel of 2 liters in capacity and heated to 85 DEG C And 10 parts of a 3% aqueous solution of potassium persulfate as a polymerization initiator. A monomer mixture composed of 80 parts of styrene and 20 parts of divinylbenzene (m, p-mixture, purity 81%) was continuously added thereto over 3 hours while maintaining the temperature at 85 占 폚. Thereafter, after aging for 2 hours, the reaction vessel was cooled to 40 占 폚, and the contents were filtered using a nylon mesh having a graduation interval of 50 占 퐉. Further, using a cartridge filter made of polypropylene having a filtration accuracy of 10 占 퐉 Followed by pressure filtration to obtain an aqueous dispersion of the milky particle 1 (solid content 10.0%). The obtained aqueous dispersion was dried by a spray drying method (temperature 110 to 220 占 폚) using a Mini Spray Dryer B-290 manufactured by Nippon Beihisa Co., Ltd. to obtain a milky particle 1 having a particle diameter of 0.813 占 퐉.

(Rmax) and the minor axis (Rmin) of the hollow particle 1 were measured in the same manner as in the hollow particle 1. As a result, the long diameter was 0.871 mu m, the short diameter was 0.755 mu m, and the ratio (Rmax / Rmin) The number average particle size, standard deviation and particle variation coefficient of the hollow particle 1 were determined in the same manner as in the hollow particle 1. The number average particle size was 0.813 占 퐉, the standard deviation was 0.109 占 퐉 and the particle variation coefficient was 0.134.

3.1.5. Fabrication of Core Shell Particles

, 2 parts of bis (3,5,5-trimethylhexanoyl) peroxide (trade name: PERRAIL (registered trademark) 355, manufactured by Nichiyu Corporation, water solubility: 0.01%), 0.1 part of sodium dodecylbenzenesulfonate, And 17.9 parts of water were stirred and emulsified, and then further made into fine particles with an ultrasonic homogenizer (manufactured by SMT) to obtain an aqueous dispersion of polymerization initiator. To the aqueous dispersion of the polymerization initiator thus prepared was added 15 parts (150 parts as an aqueous dispersion) of the aqueous dispersion of the milky particle 1 as solid particles as core particles, followed by stirring for 16 hours. Thereafter, 680 parts of water, 90 parts of methyl methacrylate, 10 parts of ethylene glycol dimethacrylate, and 50 parts of a 10% aqueous solution of John Krill (registered trademark) 62 manufactured by BASF Co., Followed by stirring for 3 hours while further maintaining the temperature at 80 캜 to synthesize the core-shell particles in which the surface of the sealed particle 1 was polymer-coated. Thereafter, the reaction vessel was cooled to 40 占 폚, the contents were filtered using a nylon mesh having a graduation interval of 50 占 퐉, and further subjected to pressure filtration using a polypropylene cartridge filter having a filtration accuracy of 10 占 퐉, To obtain an aqueous dispersion of particles (solid content: 12.2%). The obtained aqueous dispersion was dried by a spray drying method (temperature: 110 to 220 캜) using a Mini spray dryer B-290 manufactured by Nippon Beihisa Co., Ltd. to obtain core shell particles having a particle size of 1.54 탆.

The long diameter Rmax and the short diameter Rmin of the core shell particles were measured in the same manner as the hollow particles 1 and the average value thereof was calculated. As a result, the ratio of the major axis to the minor axis was 1.56 占 퐉, the minor axis was 1.51 占 퐉, ) Was 1.03. The number average particle size, standard deviation, and particle variation coefficient of the core shell particles were determined in the same manner as for the hollow particles 1. The number average particle size was 1.540 占 퐉, the standard deviation was 0.154 占 퐉, and the particle variation coefficient was 0.100.

3.1.6. Production of dissociated particles

(M, p-mixture, purity: 81%) was added to a reaction vessel having a capacity of 2 liters, 947 parts of water, 1.6 parts of an aqueous dispersion of the seed particles A as a solid component (5.5 parts by water dispersion), 80 parts of styrene, ), 5 parts of 2-hydroxyethyl methacrylate and 0.5 part of sodium dodecylbenzenesulfonate were charged and heated to 85 deg. C with stirring and 10 parts of a 3% potassium persulfate aqueous solution as a polymerization initiator were added. Followed by aging for 6 hours while maintaining the temperature at 85 占 폚 to obtain an aqueous dispersion (solid content: 10.0%) of the first polymer particles having a particle diameter of 0.809 占 퐉.

, 2 parts of bis (3,5,5-trimethylhexanoyl) peroxide (trade name: PERRAIL (registered trademark) 355, manufactured by Nichiyu Corporation, water solubility: 0.01%), 0.1 part of sodium dodecylbenzenesulfonate, And 17.9 parts of water were stirred and emulsified, and then further made into fine particles with an ultrasonic homogenizer (manufactured by SMT) to obtain an aqueous dispersion of polymerization initiator. 15 parts (150 parts in aqueous dispersion) of the aqueous dispersion of the first polymer particles as a solid component was added to the aqueous dispersion of the polymerization initiator thus prepared, and the mixture was stirred for 16 hours. Thereafter, 680 parts of water, 90 parts of methyl methacrylate, 10 parts of ethylene glycol dimethacrylate and 50 parts of a 10% aqueous solution of Zoncryl (registered trademark) 62 manufactured by BASF were added and stirred for 3 hours while maintaining the temperature at 40 占 폚 And further stirred for 3 hours while maintaining the temperature at 80 캜 to synthesize the releasing particles. Thereafter, the reaction vessel was cooled to 40 占 폚, and the contents were filtered using a nylon mesh having a graduation interval of 50 占 퐉, and further subjected to pressure filtration using a cartridge filter made of polypropylene with a filtration accuracy of 10 占 퐉, Of an aqueous dispersion (solid content: 12.2%). The resulting aqueous dispersion was dried by a spray drying method (temperature 110 to 220 占 폚) using a Mini Spray Dryer B-290 manufactured by Nippon Beihisa Co., Ltd. to obtain a release particle having a particle diameter of 1.67 占 퐉.

(Rmax / Rmin) of the long diameter and the short diameter of the long diameter and the short diameter (Rmin) were 1.81 mu m and 1.53 mu m, respectively, as a result of calculating the average value. Was 1.18. The number average particle diameter, standard deviation, and particle variation coefficient of the release particles were determined in the same manner as the hollow particles 1. The number average particle diameter was 1.670 mu m, the standard deviation was 0.147 mu m, and the particle variation coefficient was 0.088.

3.1.7. Production of calcium carbonate particle A

The calcium carbonate purchased from Wako Junyaku Kogyo Co., Ltd. was pulverized with agate mortar and further classified by a water sieve, and then spray-dried using a mini spray dryer B-290 manufactured by Nihonbihisa Co., Ltd. Temperature: 110 to 220 占 폚) to prepare light-diffusing particles having the particle diameter / short-width ratio shown in Table 1. The number average particle diameter, standard deviation, and particle variation coefficient of the calcium carbonate particle A were determined in the same manner as in the hollow particle 1, using the aqueous dispersion obtained by dispersing the obtained calcium carbonate particle A in water using an ultrasonic disperser. As a result, A particle diameter of 2.23 mu m, a standard deviation of 0.443 mu m, and a coefficient of variation of particle of 0.199. The long diameter (Rmax) and the short diameter (Rmin) of the calcium carbonate particle A were measured in the same manner as in the hollow particle 1 and the average value thereof was calculated. As a result, the long diameter was 2.32 mu m, the short diameter was 2.13 mu m, Rmax / Rmin) was 1.09.

3.1.8. Fabrication of barium sulfate particle A

Barium sulfate purchased from Wako Junyaku Kogyo Co., Ltd. was pulverized by agar mortar and classified by further investigation, and then spray-dried using a mini spray dryer B-290 manufactured by Nippon Beehisa Co., Ltd. (temperature 110 to 220 Lt; 0 &gt; C) to prepare light-diffusing particles having the particle diameter / short-width ratio described in Table 1. The number average particle diameter, standard deviation, and particle variation coefficient of the barium sulfate particles A were determined in the same manner as in the case of the hollow particles 1, using the aqueous dispersion obtained by dispersing the obtained barium sulfate particles A in water using an ultrasonic disperser. A particle diameter of 1.970 mu m, a standard deviation of 0.355 mu m, and a coefficient of variation of particle of 0.180. The long diameter (Rmax) and the short diameter (Rmin) of the barium sulfate particle A were measured in the same manner as the hollow particle 1 and the average value thereof was calculated. As a result, the long diameter and the short diameter were 2.14 mu m and 1.80 mu m, Rmax / Rmin) was 1.19.

3.1.9. Fabrication of Barium Sulfate Particle B

Barium sulfate purchased from Wako Junyaku Kogyo Co., Ltd. was pulverized by magnetic induction and classified by further investigation, and then spray-dried using a mini spray dryer B-290 manufactured by Nippon Beehisa Co., Ltd. (temperature 110 to 220 Lt; 0 &gt; C) to prepare light-diffusing particles having the particle diameter / short-width ratio described in Table 1. The number average particle size, standard deviation and particle variation coefficient of the barium sulfate b particles B were determined in the same manner as in the case of the hollow particles 1, using the aqueous dispersion obtained by dispersing the obtained barium sulfate particles B in water using an ultrasonic disperser. A particle diameter of 3.97 mu m, a standard deviation of 0.881 mu m, and a particle variation coefficient of 0.222. The long diameter (Rmax) and the short diameter (Rmin) of the barium sulfate particles B were measured in the same manner as the hollow particles 1 and the average value thereof was calculated. As a result, the long diameter was 4.99 mu m, the short diameter was 2.95 mu m, Rmax / Rmin) was 1.69.

3.1.10. Production of titanium dioxide particle A

Titanium dioxide purchased from Wako Junyaku Kogyo Co., Ltd. was pulverized by agar mortar and classified by further investigation, and then spray-dried using a mini spray dryer B-290 type manufactured by Nippon Beehisa Co., Ltd. (temperature 110 to 220 Lt; 0 &gt; C) to prepare light-diffusing particles having the particle diameter / short-width ratio described in Table 1. The number average particle size, standard deviation and particle variation coefficient of the titanium dioxide particle A were determined in the same manner as in the case of the hollow particle 1, using the aqueous dispersion obtained by dispersing the obtained titanium dioxide particle A in water using an ultrasonic disperser. As a result, A particle diameter of 2.67 mu m, a standard deviation of 0.400 mu m, and a coefficient of variation of particle of 0.150. The long diameter (Rmax) and the short diameter (Rmin) of the titanium dioxide particle A were measured in the same manner as in the case of the hollow particle 1 and the average value thereof was calculated. As a result, the long diameter was 2.73 占 퐉, the short diameter was 2.60 占 퐉, Rmax / Rmin) was 1.05.

3.2. Example 1

20 parts by mass of the hollow particles 1 prepared above, 33.1 parts by mass of bisphenol A epoxy diacrylate (trade name: CN104, manufactured by Arc Machinery Co., Ltd.), 2-hydroxy-3-phenoxypropyl acrylate (Trade name "KAYAMER PM-2", manufactured by Nippon Kayaku Co., Ltd.), 40.1 parts by mass of polyvinyl alcohol (manufactured by Nippon Kayaku Co., Ltd., Frontier PGA manufactured by Daiichi Kyoei Yakuhin Co., , 6.3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufactured by BASF Japan Ltd.), 0.08 parts by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) , And 0.04 parts by mass of 2-methyl-4-isothiazolin-3-one (manufactured by Wako Pure Chemical Industries, Ltd.) were further mixed so that the water content in the composition was 0.4 parts by mass. The mixture was kneaded using a planetary stirring apparatus (type "KK-50S", manufactured by Kurashiki Boshiki Co., Ltd.) to prepare a composition for a light guide plate containing hollow particles 1 as light diffusing particles (A).

Subsequently, a light guiding substrate made of glass (product name "OA-10G" manufactured by Nippon Denshikai Co., Ltd., a glass substrate having a surface roughness Ra of 0.5 nm manufactured by an overflow method) was placed on a work stage, Was screen printed in the form of dots and then cured by ultraviolet irradiation to prepare a light guide plate having a light diffusion portion.

The application conditions of the composition for a light guide plate, the ultraviolet ray irradiation conditions, and the evaluation method are as follows.

<Coating Conditions>

The dots were screen-printed under the following conditions. A pitch diameter of 300 mu m, a dot film thickness of 15 mu m, and a dot pattern pitch of 500 to 2000 mu m.

Dimensions of the light guiding board: length (length in the light guiding direction) 718 mm, width 413 mm, thickness 2 mm

Coated surface: Outgoing surface (surface of light guiding substrate)

· Application method: Screen printing

· Mesh: 420 mesh / inch

· Sweep angle: 50 °

· Skid speed: 65 mm / s

· Ski pressure: 0.198 kgf / ㎠

Clearance: 1.1 mm

<Ultraviolet irradiation condition>

· Lamp: Ultra high pressure mercury lamp (irradiation wavelength 280 nm or more and 500 nm or less)

Irradiation dose: 550 mJ / cm 2 (365 nm)

<Evaluation method>

(1) Evaluation of hardenability

When the composition for a light guide plate is cured by irradiation of ultraviolet rays as described above and then the formed light diffusing portion is promoted to recognize the tack, it is judged that the curing is defective and "x" The case is judged as good in hardenability and is indicated in the table as &quot;? &Quot;.

(2) Evaluation of luminance unevenness and chromaticity unevenness of light guide plate

A light source in which white LEDs are arranged in a line on both ends of the manufactured light guide plate is provided, a white diffuse reflection sheet is laminated on the back side of the light guide plate, and a light diffusion film is laminated on the side of the front side to form a side light type backlight did. The sidelight type backlight is observed with a naked eye from a position 2 m away from the front, and uniform brightness and irregularity in luminance can not be recognized on the whole surface, and when it can be judged very good, &quot; In the case where it can be judged to be usable for applications in which strictly homogeneous luminance is not required, "○", obviously unevenness in luminance is recognized, and when it is difficult to use, it is judged to be defective and " .

In addition, when the sidelite type backlight is observed by visual observation from a position 2 m away from the front, the chromaticity unevenness can not be recognized, the color is white, and when it can be judged very good, &quot; . However, in the case where it can be judged that it can be used for applications in which strict white light emission is not required, it is marked as &quot;? &Quot;, chromaticity unevenness in the surface is large,

(3) Storage stability

The composition for a light guide plate prepared above was stored under a light-shielding environment at room temperature, and a light guide plate was produced every month by the above-described method, and the storage stability of the composition for a light guide plate was evaluated by performing the above described luminance unevenness evaluation and chromaticity unevenness evaluation. &Quot; &quot; in the case where the brightness unevenness and chromaticity unevenness of the light guide plate are equivalent to those in the case where the composition for the light guide plate immediately after preparation is equivalent to &quot; When the judgment of use is different, "x" is indicated in the table.

&Lt; Measurement of reflectance of cured film &

A light guiding substrate made of glass (manufactured by Nippon Denshikkarasu Co., Ltd., trade name "OA-10G", a glass substrate having a surface roughness Ra of 0.5 nm manufactured by an overflow method) was placed on a work stage and the above- The composition for a light guide plate was coated under the conditions and then cured by ultraviolet irradiation under the above-described ultraviolet irradiation conditions to prepare a cured film of a composition for a light guide plate having a thickness of 10 mu m. (% Rmax) at a wavelength of 300 to 380 nm from the reflection spectrum measured using a spectrophotometer (type V-670, manufactured by Nippon Bunko K.K.) for the cured film thus produced, (% Rmin), and the maximum reflectance (% Rmax) and the minimum reflectance (% Rmin) at a wavelength of 400 to 800 nm. The results are also shown in Table 1.

3.3. Examples 2 to 3

A composition for a light guide plate was prepared and evaluated in the same manner as in Example 1 except that the kinds of the light-diffusing particles (A) were the particles described in Table 1 and the amount of each component was changed.

3.4. Example 4

10 parts by mass of the core shell particles prepared above, 36.6 parts by mass of bisphenol A epoxy diacrylate (trade name: CN104, manufactured by Arc Machinery Co., Ltd.), 2-hydroxy-3-phenoxypropyl acrylate (Trade name: KAYAMER PM-2, manufactured by Nippon Kayaku Co., Ltd.) 0.44 (trade name, manufactured by Nippon Kayaku Co., Ltd., trade name "New Frontier PGA") and 44.4 parts by mass of bis (2- (meth) acryloyloxyethyl) , 7.0 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufactured by BASF Japan Ltd.), 0.05 parts by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) And 0.1 part by mass of 2-methyl-4-isothiazolin-3-one (manufactured by Wako Pure Chemical Industries, Ltd.) were further mixed so that the water content in the composition was 1.5 parts by mass. Further, a composition for a light guide plate containing core shell particles as light diffusing particles (A) was prepared by kneading using a planetary stirring apparatus (type "KK-50S", manufactured by Kurashiki Boshiki Co., Ltd.) The evaluation was carried out in the same manner.

3.5. Example 5

30 parts by mass of the above-prepared release particles, 28.8 parts by mass of bisphenol A epoxy diacrylate (trade name: CN104, manufactured by Arc Machinery Co., Ltd.), 2-hydroxy-3-phenoxypropyl acrylate 34.8 parts by mass, trade name "New Frontier PGA") and 0.35 mass parts of bis (2- (meth) acryloyloxyethyl) phosphate (trade name "KAYAMER PM-2", manufactured by Nippon Kayaku Co., , 5.45 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufactured by BASF Japan Ltd.), 0.1 part by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) -Methyl-4-isothiazolin-3-one (manufactured by Wako Pure Chemical Industries, Ltd.) was further mixed with 0.4 part by mass of water in the composition. Further, a composition for a light guide plate containing the releasing particles as the light-diffusing particles (A) was prepared by kneading using a planetary stirring apparatus (type "KK-50S" manufactured by Kurashiki Boshiki Co., Ltd.) And evaluated.

3.6. Example 6

9 parts by mass of the calcium carbonate particle A prepared above, 37.6 parts by mass of bisphenol A epoxy diacrylate (trade name: CN104, manufactured by Arc Machinery Co., Ltd.), 2-hydroxy-3-phenoxypropyl acrylate (Trade name "KAYAMER PM-2", manufactured by Nippon Kayaku Co., Ltd.) and 45.6 parts by mass of bis (2- (meth) acryloyloxyethyl) phosphate ester (trade name "New Frontier PGA" (Manufactured by BASF Japan Ltd.), 7.17 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufactured by BASF Japan Ltd.), 0.06 parts by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, And 0.02 parts by mass of 2-methyl-4-isothiazolin-3-one (manufactured by Wako Pure Chemical Industries, Ltd.) were further mixed so that the water content in the composition was 0.02 parts by mass. Further, a composition for a light guide plate containing calcium carbonate particles A as light diffusing particles (A) was prepared by kneading using a planetary stirring apparatus (type "KK-50S" manufactured by Kurashiki Boshiki Co., Ltd.) And the evaluation was carried out in the same manner.

3.7. Example 7

9 parts by mass of the barium sulfate particle A prepared above, 37.6 parts by mass of bisphenol A epoxy diacrylate (trade name: CN104, manufactured by Arc Machinery Co., Ltd.), 2-hydroxy-3-phenoxypropyl acrylate (Trade name "KAYAMER PM-2", manufactured by Nippon Kayaku Co., Ltd.) and 45.6 parts by mass of bis (2- (meth) acryloyloxyethyl) phosphate ester (trade name "New Frontier PGA" , 7.17 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufactured by BASF Japan Ltd.), 0.05 parts by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) , And 0.03 parts by mass of 2-methyl-4-isothiazolin-3-one (manufactured by Wako Pure Chemical Industries, Ltd.) were further mixed and 0.03 parts by mass of water in the composition was added. Further, a composition for a light guide plate containing barium sulfate particles A as light diffusing particles (A) was prepared by kneading using a planetary stirring apparatus (type "KK-50S", manufactured by Kurashiki Boshiki Co., Ltd.) And the evaluation was carried out in the same manner.

3.8. Example 8

9 parts by mass of the above-prepared titanium dioxide particle A, 37.6 parts by mass of bisphenol A epoxy diacrylate (trade name: CN104, manufactured by Arc Machinery Co., Ltd.), 2-hydroxy-3-phenoxypropyl acrylate (Trade name "KAYAMER PM-2", manufactured by Nippon Kayaku Co., Ltd.) and 45.6 parts by mass of bis (2- (meth) acryloyloxyethyl) phosphate ester (trade name "New Frontier PGA" , 4.17 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufactured by BASF Japan Ltd.), 0.3 parts by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) And 0.03 parts by mass of 2-methyl-4-isothiazolin-3-one (manufactured by Wako Pure Chemical Industries, Ltd.) were further mixed, and the water content in the composition was 0.04 parts by mass. Further, a composition for a light guide plate containing titanium dioxide particle A as light diffusing particles (A) was prepared by kneading using a planetary stirring apparatus (type "KK-50S" manufactured by Kurashiki Boshiki Co., Ltd.) And the evaluation was carried out in the same manner.

3.9. Comparative Examples 1 to 2

A composition for a light guide plate was prepared and evaluated in the same manner as in Example 1, except that the light-diffusing particles (A) were changed to the particles and the contents described in Table 1, and the amount of each component was changed.

3.10. Evaluation results

Table 1 shows the composition, physical properties, and evaluation results of the composition for a light guide plate used in each of the examples and comparative examples.

In addition, for each of the materials described in Table 1, the following goods or compounds were used.

The dispersion medium (B)

B1: Bisphenol A epoxy diacrylate, trade name "CN104" (trade name, manufactured by Arc Machinery Co., Ltd.)

B2: 2-hydroxy-3-phenoxypropyl acrylate, trade name "New Frontier PGA", manufactured by Daiichi Kyo Seiyaku Co.,

Radical scavenger (C): Hydroquinone monomethyl ether, manufactured by Wako Junya Kogyo Co., Ltd.

Photopolymerization initiator: 1-hydroxycyclohexyl phenyl ketone, trade name: Irgacure 184 (trade name, manufactured by BASF Japan)

Phosphate ester: bis (2- (meth) acryloyloxyethyl) phosphate ester, trade name "KAYAMER PM-2", manufactured by Nippon Kayaku Co.,

Isothiazoline compound: 2-methyl-4-isothiazolin-3-one, manufactured by Wako Pure Chemical Industries, Ltd.

Water: Ion exchange water

It can be seen that the compositions for the light guide plates of Examples 1 to 8 have good curability and excellent storage stability. Further, since the light guide plate manufactured using the compositions for the light guide plates of Examples 1 to 8 can effectively suppress unevenness in brightness and chromaticity unevenness, it is found that the surface light emission of the light guide plate is excellent in homogeneity and exhibits good light emission characteristics have.

The present invention is not limited to the above-described embodiment, and various modifications are possible. The present invention includes substantially the same configuration as the configuration described in the embodiment (for example, a configuration having the same function, method, and result, or a configuration having the same purpose and effect). The present invention also includes a configuration in which a non-essential portion of the configuration described in the above embodiments is replaced with another configuration. The present invention also includes a configuration that achieves the same operational effects as the configuration described in the above embodiment, and a configuration that can achieve the same purpose. The present invention also includes a configuration in which known technologies are added to the configurations described in the above embodiments.

1: light guide plate
3: Light source
11:
12:
20: surface light source device
30: transmission type image display unit
40a, 40b, 40c: Light diffusion particles
50a, 50b, 50c, 50d, 50e, 50f:
52a, 52b, 52c, 52d, 52e, and 52f: first light diffusion particles
54a, 54b, 54c, 54d, 54e, and 54f:
100: transmission type image display device (liquid crystal display device)
S1, S2: emission surface (of the light-guiding substrate)
S3 ₁ , S3 ₂ , S3 ₃ , and S3 ₄ :

Claims (7)

As a composition for a light guide plate containing light diffusing particles (A) and a dispersion medium (B)
A composition for a light guide plate having a reflectance of 0 to 50% at a wavelength of 300 to 380 nm and a reflectance of 30 to 99% at a wavelength of 400 to 800 nm in a 10 μm thick cured film produced using the composition. The method according to claim 1,
Wherein a value obtained by dividing the standard deviation of the particle size distribution of the light-diffusing particles (A) by the number average particle size (particle variation coefficient) is 0.01 to 0.2. The method according to claim 1,
Wherein the ratio (Rmax / Rmin) of the major axis (Rmax) to the minor axis (Rmin) of the light diffusing particles (A) is in the range of 1.01 to 1.2. The method according to claim 1,
A composition for a light guide plate comprising a photopolymerizable component as the dispersion medium (B). The method according to claim 1,
Further, a composition for a light guide plate containing a radical scavenger (C). The method according to claim 1,
Further, a composition for a light guide plate containing an isothiazoline compound. A light guide plate manufactured by using the composition for a light guide plate according to any one of claims 1 to 6.

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