JP2017143036A - Composition for light guide plate and light guide plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for light guide plates that makes it possible to prepare a light guide plate that allows light to be emitted from the light emission surface side with improved brightness, and also has excellent storage stability.SOLUTION: A composition for light guide plates comprises a light diffusion particle (A), a dispersion medium (B), and a radical scavenger (C). When a content of the light diffusion particle (A) is defined as Ma pts.mass and a content of the radical scavenger (C) is defined as Mc pts.mass, the ratio between them, Ma/Mc, is 20-500.SELECTED DRAWING: Figure 1

Description

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

  Surface light-emitting devices used for liquid crystal display panels, signboards, and the like include a direct type in which a light source is arranged in a plane and a uniform light emission is formed by a diffusion plate or the like, and an edge light type in which a light source is arranged on an end surface of a light guide plate. Are known.

  The edge light type surface light emitting device includes a light source and a light guide plate. The light guide plate includes a light guide substrate and a light diffusing unit, and light from the light source propagates through the light guide plate and is emitted in a planar shape by the light diffusing unit disposed on the surface of the light guide substrate. As described in Patent Documents 1 to 4, such a light guide plate is manufactured by applying a light guide plate composition containing light diffusion particles to a light guide substrate to produce a light diffusion portion.

Japanese Patent Laid-Open No. 09-145937 JP 2010-144771 A JP 2012-216528 A JP 2012-178345 A

  Such a surface light emitting device is required to further improve energy efficiency, and a technique for sufficiently efficiently extracting light supplied from the light source to the light guide substrate to the light exit surface side of the light guide substrate is required. ing. However, the conventional light guide plate for edge light type surface light emitting devices has a tendency that the vicinity of the light source (for example, LED) is bright, becomes darker as it is farther from the light source, and becomes more yellowish as the light diffusion part is farther away from the light source. . If such brightness unevenness or chromaticity unevenness occurs, it becomes difficult to sufficiently extract uniform surface light emission on the light exit surface side of the light guide substrate.

  Therefore, some aspects according to the present invention can produce a light guide plate that can emit light uniformly to the light exit surface side with higher luminance by solving at least a part of the above-described problems, and The present invention provides a light guide plate composition having excellent storage stability.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the composition for light guide plates according to the present invention is:
Light diffusing particles (A);
A dispersion medium (B);
A radical scavenger (C),
When the content of the light diffusing particles (A) is Ma parts by mass and the content of the radical scavenger (C) is Mc parts by mass, the ratio Ma / Mc of both is 20 to 500. To do.

[Application Example 2]
In the light guide plate composition of Application Example 1,
The dispersion medium (B) can contain a photopolymerizable component.

[Application Example 3]
In the light guide plate composition of Application Example 1 or Application Example 2,
Furthermore, an isothiazoline-based compound can be contained.

[Application Example 4]
In the light guide plate composition of any one of Application Examples 1 to 3,
A 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 5]
In the composition for a light guide plate of any one of Application Examples 1 to 4,
The ratio (Rmax / Rmin) of the major axis (Rmax) to the minor axis (Rmin) of the light diffusing particles (A) may be in the range of 1.01 to 1.2.

[Application Example 6]
One aspect of the light guide plate according to the present invention is:
It is produced using the composition for light guide plates in any one of the application examples 1 to 5.

  According to the composition for a light guide plate according to the present invention, it is possible to suppress luminance unevenness and chromaticity unevenness by applying the composition to a light guide substrate to form a light diffusion portion. A light guide plate that can emit light uniformly to the light emitting surface side with high luminance can be manufactured. Moreover, the composition for light-guide plates which concerns on this invention is excellent also in storage stability.

It is a section conceptual diagram showing an example of an edge light type surface emitting device. It is a top view of the side by which the light-diffusion part of the light-guide plate is formed. It is explanatory drawing which shows typically the concept of the long diameter and short diameter of a light-diffusion particle (A). It is explanatory drawing which shows typically the concept of the long diameter and short diameter of a light-diffusion particle (A). It is explanatory drawing which shows typically the concept of the long diameter and short diameter of a light-diffusion particle (A). It is explanatory drawing which shows the concept of an irregular shape particle | grain schematically. It is explanatory drawing which shows the concept of an irregular shape particle | grain schematically. It is explanatory drawing which shows the concept of an irregular shape particle | grain schematically. It is explanatory drawing which shows the concept of an irregular shape particle | grain schematically. It is explanatory drawing which shows the concept of an irregular shape particle | grain schematically. It is explanatory drawing which shows the concept of an irregular shape particle | grain schematically.

  Hereinafter, preferred embodiments according to the present invention will be described in detail. It should be understood that the present invention is not limited only to the following embodiments, and includes various modifications that are implemented within a scope that does not change the gist of the present invention. In this specification, “(meth) acrylic acid” is a concept encompassing both “acrylic acid” and “methacrylic acid”. Further, “˜ (meth) acrylate” is a concept encompassing both “˜acrylate” and “˜methacrylate”. Further, “(meth) acryloylyl” is a concept encompassing both “acryloyl” and “methacryloyl”.

  In the present specification, the light diffusion particles (A) are abbreviated as “component (A)”, the dispersion medium (B) as “component (B)”, and the radical scavenger (C) as “component (C)”. May be used.

1. Composition for Light Guide Plate The composition for a light guide plate according to this embodiment (hereinafter also simply referred to as “composition”) is a composition used for forming a light diffusion portion of a light guide plate. The composition for light guide plates which concerns on this embodiment contains a light-diffusion particle (A), a dispersion medium (B), and a radical scavenger (C). Hereinafter, components that can be included in the light guide plate composition according to the present embodiment will be described in detail.

1.1. Light diffusing particles (A)
As the light diffusing particles (A), inorganic particles or organic particles can be used. As 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 organic particles, irregular organic particles having a non-spherical shape, and the like can be preferably used. The light diffusion particles (A) used in the present invention can be used singly or in combination of two or more.

  The number average particle diameter (Dn) of such light diffusing particles (A) is preferably 0.3 to 2 μm, and 0.4 to 1.8 μm when the light diffusing particles (A) are organic particles. More preferred. On the other hand, when the light diffusing particles (A) are inorganic particles, 0.5 to 3 μm is preferable, and 0.8 to 2.8 μm is more preferable. The number average particle diameter (Dn) of the light diffusing particles (A) can be measured by using a particle size distribution measuring apparatus based on a dynamic light scattering method.

  “Number average particle diameter measured by dynamic light scattering method” refers to fluctuations in scattered light intensity using a particle size distribution analyzer based on the dynamic light scattering method, and autocorrelation using the photon correlation method. This refers to the number average particle size obtained by obtaining a function and applying the cumulant method and the histogram method analysis.

  The particle size distribution measuring apparatus based on the dynamic light scattering method is a nanoparticle analyzer “Delsa Nano S” manufactured by Beckman Coulter, “Zetasizer nano zs” manufactured by Malvern, and “ELSZ-” manufactured by Otsuka Electronics Co., Ltd. 1000ZS "and the like.

  Inorganic particles having a number average particle diameter (Dn) within the above range can be obtained from commercially available products by appropriately selecting based on the particle size distribution. Core-shell particles, hollow particles, irregularly shaped particles and the like can be produced by the methods described in International Publication Nos. 2005/071014 and JP2013-93205A.

  The particle diffusion coefficient (CV value) of the light diffusing particles (A) contained in the light guide plate composition according to this embodiment is preferably in the range of 0.01 to 0.2, preferably 0.02 to 0.00. More preferably, it is in the range of 15. In the light guide plate, it is necessary to diffuse light uniformly on the light exit surface side. However, if the particle variation coefficient of the light diffusion particle (A) is within the above range, the particle size distribution degree causes the light to diffuse uniformly. It became clear that it was possible to create an easy-to-use state and reduce the diffuse reflection of light. Thereby, the light extraction efficiency of the light guide plate is improved.

The particle variation coefficient (CV value) can be obtained by the following equation (1).
CV value = standard deviation of particle size distribution (σ) / number average particle size (Dn) (1)

The ratio (Rmax / Rmin) of the major axis (Rmax) to the minor axis (Rmin) in the light diffusing particles (A) is preferably in the range of 1.01 to 1.2, and is preferably 1.02 to 1.15. More preferably, it is in the range. When the ratio (Rmax / Rmin) is in the above range, the surface area of the light diffusing particles (A) increases and the surface of the light diffusing particles (A) is not a true curved surface, so that the light scattering efficiency increases. The average brightness of the light guide plate is increased.

  The major axis (Rmax) of the light diffusing particle (A) is the longest straight line among the straight lines connecting the ends of the image of one independent light diffusing particle photographed by a transmission electron microscope. It means distance. The short diameter (Rmin) of the light diffusing particle (A) is the shortest straight line among the straight lines connecting the end portions of the image of one independent light diffusing particle image taken by a transmission electron microscope. Means the distance.

  For example, as shown in FIG. 3, when an image of one independent light diffusing particle 40a photographed by a transmission electron microscope is elliptical, the major axis a of the elliptical shape is defined as the major axis (Rmax) of the light diffusing particle. The minor axis b is judged as the minor axis (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, of the straight lines connecting the end portions of the image The longest distance c is determined as the long diameter (Rmax) of the light diffusing particles, and the shortest diameter d of the straight lines connecting the end portions of the image is determined as the short diameter (Rmin) of the light diffusing particles. As shown in FIG. 5, when an image of one independent light diffusion particle 40c photographed by a transmission electron microscope is an aggregate of three or more primary particles, a straight line connecting the end portions of the image. The longest distance e is determined as the long diameter (Rmax) of the light diffusing particles, and the shortest diameter f of the straight lines connecting the end portions of the image is determined as the short diameter (Rmin) of the light diffusing particles.

  After measuring the major axis (Rmax) and minor axis (Rmin) of 20 light-diffusing particles (A), for example, and calculating the average value of the major axis (Rmax) and minor axis (Rmin) by the determination method as described above. The ratio (Rmax / Rmin) between the average value of the major axis and the average value of the minor axis can be obtained.

  Further, the light diffusing particle (A) may be, for example, a “shaped particle” having a structure in which the first light diffusing particle and the second light diffusing particle are in close contact with each other. In this case, the light diffusion particle (A) may have a structure in which the other light diffusion particle (A) is disposed on at least a part of the surface of any one of the light diffusion particles (A). Here, “an irregular shape” in the present specification means that two particles are arranged asymmetrically with respect to the center point of the whole particle.

  6 to 11 are explanatory views schematically showing the concept of irregularly shaped particles. Examples of the “irregular particles” include structures as shown in FIGS.

  In the deformed particle 50a shown in FIG. 6, the second light diffusion particle 54a is in close contact with a part of the surface of the first light diffusion particle 52a, and the second light diffusion particle 54a is the first light diffusion particle 52a. It has a structure protruding from the surface.

  In the deformed particle 50b shown in FIG. 7, the second light diffusing particle 54b is completely included in the first light diffusing particle 52b, and the second light is reflected at one point on the surface of the first light diffusing particle 52b. It is in contact with the diffusion particles 54b and has a substantially spherical structure as a whole.

  The deformed particle 50c shown in FIG. 8 has a substantially spherical structure as a whole, with the first light diffusing particle 52c and the second light diffusing particle 54c being in close contact with each other. In the deformed particle 50c shown in FIG. 8, the first light diffusing particle 52c and the second light diffusing particle 54c have the same surface area, but this is not particularly limited.

The deformed particle 50d shown in FIG. 9 includes the second light diffusing particle 54d inside the first light diffusing particle 52d, and the curved surface of the second light diffusing particle 54d appears on the surface of the deformed particle 50d. As a whole, it has a substantially spherical structure.

  The deformed particle 50e shown in FIG. 10 has an oval spherical structure like a rugby ball as a whole of the deformed particle 50c shown in FIG. In the irregular shaped particle 50e shown in FIG. 10, the first light diffusing particle 52e and the second light diffusing particle 54e have the same surface area, but this is not particularly limited.

  The irregularly shaped particle 50f shown in FIG. 11 has a substantially spherical first light diffusing particle 52f and a substantially spherical second light diffusing particle 54f in close contact with each other, and has a twin-spherical structure as a whole. Yes.

  When the irregularly shaped particle is an organic particle, it is not particularly limited, but is preferably composed of two particles of a first light diffusing particle and a second light diffusing particle. 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, but at least of the monomer units contained in the first light diffusing particles. One type is preferably different from the monomer unit contained in the second light diffusion particle. That is, in this case, at least one of the monomer units constituting the odd-shaped organic particles is contained only in one of the first light diffusion particles and the second light diffusion particles. Will be. Thereby, as shown in FIGS. 6-11, a 1st light-diffusion particle and a 2nd light-diffusion particle can be isolate | separated asymmetrically.

  When the light diffusing particles (A) are irregularly shaped particles, the irregularly shaped particles substantially constitute one particle, and therefore the major axis and minor axis of the irregularly shaped particles are measured as follows. For example, when the light diffusing particles (A) are substantially spherical particles 50a having spherical protrusions as shown in FIG. 6, the major axis (Rmax) is the second light diffusing particles 54a from the end of the first light diffusing particles 52a. It is represented by the distance to the end of The short diameter (Rmin) is represented by the diameter of the larger particle (first light diffusion particle 52a in FIG. 6).

  When the light diffusing particles (A) are irregularly shaped particles and the irregularly shaped particles are organic particles, they can be produced by a method described in JP 2013-098123 A, for example. Further, when the irregularly shaped particles are inorganic particles, they can be appropriately produced by a known method such as a pulverization method or a classification operation after pulverization.

  The absolute value | Δn | of the difference in refractive index between the light diffusing particles (A) and the photopolymerizable component to be described later after polymerization is preferably 0.02 ≦ | Δn | ≦ 1.3. For example, when a photopolymerizable monomer or photopolymerizable oligomer is used as the photopolymerizable component, calcium carbonate particles (refractive index: n = 1.59), barium sulfate particles (refractive index: n) are used as the light diffusing particles (A). = 1.64) and at least one of titanium dioxide particles (refractive index: n = 2.7) satisfies the above condition.

  The light guide plate composition according to this embodiment is in a state in which the light diffusion particles (A) as described above are dispersed in the dispersion medium (B). The content of the light diffusing particles (A) in the light guide plate composition according to the present embodiment is such that when the light diffusing particles (A) are inorganic particles, the total mass of the composition is 100% by mass. Preferably, it is 0.5-20 mass%, More preferably, it is 1-15 mass%, Most preferably, it is 3-12 mass%. When the light diffusing particles (A) are organic particles, when the total mass of the composition is 100% by mass, preferably 0.5 to 40% by mass, more preferably 5 to 35% by mass, Especially preferably, it is 10-30 mass%. When the content of the light diffusing particles (A) is in the above range, the storage stability of the composition is good, and the coating property of the composition is good. Is easily formed.

1.2. Dispersion medium (B)
The composition for light guide plates which concerns on this embodiment contains a dispersion medium (B). When producing a light-diffusion part using the photocurable type composition for light-guide plates, it is preferable to use a photopolymerizable component as a dispersion medium (B). By using the photopolymerizable component, it is possible to suppress the generation of voids in the light diffusion portion described later, and to further suppress irregular reflection due to the generation of voids. 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, compounds described in International Publication No. 2005/071014 and JP2013-93205A can be used in a timely manner.

  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 vinyl include styrene, α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, o-ethyl styrene, m-ethyl styrene, p-ethyl styrene, p-tert-butyl styrene. , M-divinylbenzene, p-divinylbenzene, m-diisopropenylbenzene, p-diisopropenylbenzene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 1,1-diphenylethylene, p-methoxy Examples thereof include styrene, N, N-dimethyl-p-aminostyrene, N, N-diethyl-p-aminostyrene, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine and the like.

  Examples of the unsaturated nitrile include (meth) acrylonitrile, α-chloroacrylonitrile, α-chloromethylacrylonitrile, α-methoxyacrylonitrile, α-ethoxyacrylonitrile, crotonic acid nitrile, cinnamic nitrile, itaconic acid dinitrile, maleic acid dinitrile, Examples include fumarate dinitrile.

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

(Meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec -Butyl (meth) acrylate, tert-butyl (meth) acrylate, n-amyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate (Meth) acrylic acid esters such as 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2- (n-propoxy) ethyl (meth) acrylate;
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, [4- (hydroxymethyl) cyclohexyl] methyl (meth) acrylate Hydroxyl group-containing (meth) acrylic acid esters such as 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 esters such as cyanoethyl (meth) acrylate and cyanopropyl (meth) acrylate; 2-phenoxyethyl (meth) acrylate, 2-phenoxypropyl (meth) acrylate, 3-phenoxypropyl (meth) (Meth) acrylic acid aryloxyalkyl esters such as acrylates;
(Meth) acrylic acid monoesters of alkoxy polyalkylene glycols such as methoxypolyethylene glycol, ethoxypolyethylene glycol, methoxypolypropylene glycol, ethoxypolypropylene glycol; (meth) of aryloxy polyalkylene glycols such as phenoxypolyethylene glycol and phenoxypolypropylene glycol Acrylic acid monoesters; (meth) acrylic acid diesters of alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol;
(Meth) acrylic acid diesters of polyalkylene glycols such as polyethylene glycol and polypropylene glycol (the number of alkylene glycol units is 2 to 23, for example), both terminal hydroxy polybutadiene, both terminal hydroxy polyisoprene, both terminal hydroxy butadiene-acrylonitrile copolymer, (Meth) acrylic acid diester of a polymer having hydroxyl groups at both ends, such as both ends hydroxypolycaprolactone;
Trivalent or higher polyvalent groups such as glycerin, 1,2,4-butanetriol, trimethylolalkane (alkane has 1 to 3 carbon atoms, for example), tetramethylolalkane (alkane has 1 to 3 carbon atoms), pentaerythritol, etc. (Meth) acrylic acid diesters, (meth) acrylic acid triesters or (meth) acrylic acid tetraesters such as (meth) acrylic acid oligoesters;
And (meth) acrylic acid oligoesters such as (meth) acrylic acid triesters or (meth) acrylic acid tetraesters of polyalkylene glycol adducts of trihydric or higher polyhydric alcohols.

  Examples of the unsaturated amide include (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N, N-bis (2-hydroxyethyl) (meth) acrylamide, N, N′-methylenebis (meth) acrylamide, N, N′-ethylenebis (meth) acrylamide, N, N′-hexamethylenebis (meth) acrylamide, acryloylmorpholine, crotonic acid amide, cinnamic acid amide, etc. It is done.

  As the photosensitive polymer, any known polymer can be used without particular limitation as long as a photopolymerizable group is introduced into the polymer skeleton. 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 a polyether skeleton and a polyurethane skeleton are preferable. Examples of the photopolymerizable group include (meth) acryloyl group, alkenyl group, cinnamoyl group, cinnamylideneacetyl group, benzalacetophenone group, styrylpyridine group, α-phenylmaleimide group, phenylazide group, sulfonylazide group, carbonyl Azido group, diazo group, o-quinonediazide group, furylacryloyl group, coumarin group, pyrone group, anthracene group, benzophenone group, benzoin group, stilbene group, dithiocarbamate group, xanthate group, 1,2,3-thiadiazole group, cyclo A propene group, an azadioxabicyclo group, etc. are mentioned, The preferable photopolymerizable group is a (meth) acryloyl group and a cinnamoyl group, Most preferably, it is a (meth) acryloyl group.

  In addition, the viscosity and photocurability of the composition for light-guide plates can be easily controlled by adding aliphatic urethane (meth) acrylate as a dispersion medium (B).

  The dispersion medium (B) used for this invention can be used individually by 1 type or in combination of 2 or more types.

When the dispersion medium (B) contains a photopolymerizable component, the content of the photopolymerizable component in the light guide plate composition according to the present embodiment is preferably when the total mass of the composition is 100% by mass. Is 50 to 95% by mass, more preferably 60 to 80% by mass. When the content of the photopolymerizable component is in the above range, the light diffusing particles (A) contained in the light diffusing portion formed on the surface of the light guide substrate can be held with sufficient strength, and light is produced in the manufacturing process. Generation | occurrence | production of a foreign material, such as a peeling particle (A) peeling, can be suppressed effectively.

1.3. Radical scavenger (C)
The composition for light guide plates which concerns on this embodiment contains a radical scavenger (C). By containing the radical scavenger (C), it is possible to effectively prevent polymerization of the photopolymerizable component at the storage stage of the light guide plate composition, and to suppress uneven brightness and chromaticity in the light diffusion portion. The uniformity of surface light emission of the light guide plate can be improved.

  When the content of the light diffusing particles (A) in the composition is Ma parts by mass and the content of the radical scavenger (C) is Mc parts by mass, the ratio Ma / Mc between them needs to be 20 to 500. However, it is preferably 30 to 300. By using the radical scavenger (C) within the above range, it is possible to effectively prevent the polymerization of the photopolymerizable component at the storage stage of the light guide plate composition, and also the luminance unevenness and chromaticity unevenness of the light diffusion portion. It became clear that the uniformity of surface light emission of the light guide plate was further improved.

  Although the radical scavenger (C) is contained, the mechanism of the effect of suppressing the luminance unevenness and chromaticity unevenness of the light diffusing portion and further improving the surface emission uniformity of the light guide plate is not clear, but the following I think so.

  In using the light guide plate composition, the light guide plate composition is always exposed to the outside air containing oxygen. For example, when the light diffusing portion is manufactured by printing, a certain time is required from the start to the end of printing on the light guide substrate. Thereafter, a curing process such as light irradiation is performed on the printed light guide plate composition to produce a light diffusion portion. At this time, the light diffusing portion precursor prepared at the initial stage of printing (referred to as the composition printing portion for the light guide plate before being cured to become the light diffusing portion) is the light diffusing portion precursor at the end of printing. Rather than being exposed to the atmosphere for a longer time before the curing process. It is considered that a difference occurs in the amount of oxygen absorbed by the light diffusion part precursor from the atmosphere due to the difference in exposure time in the atmosphere. As a result, it is presumed that some change occurs in the cured state of the light guide plate composition in the subsequent curing step. It is estimated that this difference in the cured state becomes a difference in the light diffusion state of each light diffusion portion, and promotes the deterioration of the uniformity of surface light emission of the light guide plate.

  However, when the light guide plate composition contains the radical scavenger (C), a difference occurs in the amount of oxygen absorbed from the atmosphere during the exposure time to the atmosphere. Even if there is a difference in the amount of oxygen contained in each light diffusing part precursor, and even if there is a difference in the amount of oxygen radicals generated from the oxygen absorbed in the subsequent curing process, a radical scavenger ( C) captures these and suppresses their action. As a result, it is presumed that the light diffusion part precursor having a more homogeneous composition could be cured and the surface emission uniformity of the light guide plate could be further improved.

  As the radical scavenger (C), for example, a phenol derivative is preferable. By using a phenol derivative, the whiteness of the light diffusion portion is further improved. Examples of the phenol derivative include hydroquinone, hydroquinone monomethyl ether, mono-tert-butylhydroquinone, catechol, 4-tert-butylcatechol, p-methoxyphenol, 2,5-di-tert-butylhydroquinone, 2,6-di- Examples thereof include hydroxyaromatic compounds such as tert-butyl-m-cresol, pyrogallol and β-naphthol, benzoquinone, 2,5-diphenyl-p-benzoquinone, p-toluquinone and p-xyloquinone. The radical scavenger (C) used in the present invention can be used alone or in combination of two or more.

  The content of the phenol derivative that is the radical scavenger (C) in the light guide plate composition according to the present embodiment is preferably 0.001 to 2% by mass when the total mass of the composition is 100% by mass. More preferably, it is 0.01-1 mass%, Most preferably, it is 0.05-0.5 mass%. If content of the phenol derivative which is a radical scavenger (C) exists in the said range, superposition | polymerization of the photopolymerizable component in the storage stage of the composition for light-guide plates can be prevented effectively. Moreover, the whiteness of the light diffusion part can be further improved.

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

  Such a photopolymerization initiator can be appropriately selected from those usually used in the field of radiation curable resins. For example, as described in International Publication No. 2005/071014 and JP2013-93205A Compound etc. are mentioned.

  Specific examples of the photopolymerization initiator include α-diketone compounds such as diacetyl, methylbenzoylformate, and benzyl; acyloins such as benzoin and pivaloin; benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and the like. Acyloin ethers; polynuclear quinones such as anthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1,4-naphthoquinone; acetophenone, 2-hydroxy-2-methyl-propiophenone, 1-hydroxycyclohexyl phenyl ketone , 2,2-dimethoxyphenylacetophenone, 2,2-diethoxyacetophenone, trichloroacetophenone and other acetophenones; benzophenone, methyl-o-ben Yl benzoate, benzophenones such as Michler's ketone; xanthone, thioxanthone, xanthone such as 2-chlorothioxanthone and the like. The photoinitiator used for this invention can be used individually by 1 type or in combination of 2 or more types.

  The content of the photopolymerization initiator in the light guide plate composition according to the present embodiment is preferably 0.1 to 20% by mass, more preferably 0.8% when the total mass of the composition is 100% by mass. 5 to 10% by mass. If content of a photoinitiator exists in the said range, since the photocurability of the composition for light-guide plates will improve, a tack-free light-diffusion part can be produced.

1.5. Other Components The light guide plate composition according to the present embodiment may contain components other than the above components, for example, isothiazoline compounds, phosphate esters, surfactants, water, binders, and the like.

<Isothiazoline compounds>
By adding the isothiazoline-based compound to the light guide plate composition according to the present embodiment, the isothiazoline compound acts as a preservative, and when the light guide plate composition is stored, bacteria, sputum, etc. grow. Generation of foreign matter can be suppressed. Furthermore, it has been clarified that the uniformity of surface light emission of the light guide plate is further improved by suppressing the luminance unevenness and chromaticity unevenness of the light diffusion portion.

The mechanism of the effect of suppressing the brightness unevenness and chromaticity unevenness of the light diffusing part and further improving the surface emission uniformity of the light guide plate by containing the isothiazoline compound is not clear, but it is considered as follows. It is done. In using the light guide plate composition, the light guide plate composition is always exposed to the outside air containing oxygen. For example, when the light diffusing portion is manufactured by printing, a certain time is required from the start of printing on the light guide substrate to the end thereof. Thereafter, a curing process such as light irradiation is performed on the printed light guide plate composition to produce a light diffusion portion. At this time, the light diffusing portion precursor prepared at the initial stage of printing (referred to as the composition printing portion for the light guide plate before being cured to become the light diffusing portion) is the light diffusing portion precursor at the end of printing. Rather than being exposed to the atmosphere for a longer time before the curing process. It is considered that a difference occurs in the amount of volatile organic substances absorbed by the light diffusion part precursor from the atmosphere due to the difference in exposure time in the atmosphere. As a result, in the subsequent curing step, some change occurs in the cured state of the composition for the light guide plate, and the difference in the cured state becomes the difference in the light diffusion state of each light diffusion portion, and the uniformity of the surface emission of the light guide plate. Presumed to promote degradation.

  On the other hand, in the composition for light guide plates according to the present embodiment, the isothiazoline-based compound tends to be retained by being adsorbed on the light diffusion particles (A). As a result, it is considered that the surface of the light diffusing particle (A) is protected by the isothiazoline-based compound, and the above-described volatile organic matter absorbed from the atmosphere can be suppressed from being adsorbed on the surface of the light diffusing particle (A). As a result, even if there is a difference in the amount of volatile organic substances contained in each light diffusing part precursor part between the initial stage and the latter part of the light diffusing part precursor part, these volatile organic substances are strongly diffused into the light diffusing particles (A). It will not be adsorbed on the surface. Because of this action, it is not held in the light diffusing part in the subsequent curing process, but is released again into the atmosphere, so the light diffusing part precursor with a more homogeneous composition can be cured and the surface emission uniformity of the light guide plate is further improved. It is speculated that it was possible.

  The isothiazoline-based 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 general formula (2) and a compound represented by the following general 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 linear or branched carbon skeleton, or may have a cyclic carbon skeleton. Moreover, it is preferable that carbon number of a hydrocarbon group is 1-12, it is more preferable that it is 1-10, and it is especially preferable that it is 1-8. Specific examples of such a hydrocarbon 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 said general formula (3), R < ⁴ > is a hydrogen atom or a hydrocarbon group, R < ⁵ > represents a hydrogen atom or an organic group each independently. When R ⁴ is a hydrocarbon group, the same hydrocarbon group as the hydrocarbon group described in the general formula (2) is exemplified. When R ⁵ is an organic group, the organic group includes an aliphatic group or an aromatic group that is an alkyl group or a cycloalkyl group, and 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 groups and cycloalkyl groups may have a substituent such as a halogen atom, an alkoxyl group, a dialkylamino group, an acyl group, or 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 said formula (3), n represents the integer of 0-4.

  Specific examples of the isothiazoline-based compound include 1,2-benzisothiazolin-3-one, 2-methyl-4,5-trimethylene-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, Nn-butyl-1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 4,5 -Dichloro-2-n-octyl-4-isothiazolin-3-one and the like can be used, and one or more of these can be used. Among these, 2-methyl-4-isothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 1,2- Benzisothiazolin-3-one is preferred.

  When the content of the light diffusing particles (A) in the composition is Ma parts by mass and the content of the isothiazoline-based compound is Md parts by mass, the ratio Ma / Md between the two is 50 to 600. It is preferable that it is 100-500. By using the isothiazoline-based compound within the above range, the storage stability of the light guide plate composition is improved, and the luminance unevenness and chromaticity unevenness of the light diffusing portion are suppressed, and the surface emission uniformity of the light guide plate is improved. It became clear that it was improved.

<Phosphate ester>
By adding a phosphoric ester to the light guide plate composition according to the present embodiment, the adhesion between the light guide substrate and the light diffusing portion can be enhanced. Moreover, when the composition for light-guide plates is made into a cured coating film, the balance between hardness, scratch resistance, wear resistance and low curl can be improved.

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

（式（１）中、Ｒ^６は水素原子又はメチル基、Ｒ^７は２価の有機基、ｎは１又は２の整数を表す。）

(In formula (1), 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 phosphate ester include mono- or bis (2- (meth) acryloyloxyethyl) phosphate ester, mono- or bis (2- (meth) acryloyloxypropyl) phosphate ester, mono- or bis (3- (meth)). (Acryloyloxypropyl) phosphate ester, mono- or bis (6- (meth) acryloyloxyhexyl) phosphate ester, mono- or bis (10- (meth) acryloyloxydecyl) phosphate ester, mono- or bis (1-chloromethyl) -2- (meth) acryloyloxyethyl) phosphate ester, 2- (meth) acryloyloxyethylphenyl phosphate ester, and the like, lactone-modified products, polyoxyalkylene-modified products, and the like. Among these, mono- or bis (2- (meth) acryloyloxyethyl) phosphate is preferable from the viewpoint of obtaining a light diffusion portion having excellent adhesion to the light guide substrate and hardness. The phosphate ester used for this invention can be used individually by 1 type or in combination of 2 or more types.

  As a commercial item of phosphate ester, Kyoeisha Chemical Co., Ltd. brand name: Light ester P-1M, P-2M, Nippon Kayaku Co., Ltd. brand name: KAYAMER PM-2, PM-21 etc. are mentioned, for example. .

  The content of the phosphate ester in the light guide plate composition according to the present embodiment is preferably 0.07 to 5% by mass, more preferably 0.2% when the total mass of the composition is 100% by mass. It is -2 mass%.

<Surfactant>
By adding a surfactant to the light guide plate composition according to this embodiment, the surface tension of the light guide plate composition and the wettability of the light guide substrate can be controlled. The surfactant is not particularly limited, but silicon surfactants and fluorine surfactants are preferable.

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

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

  The content of water in the light guide plate composition according to the present embodiment is preferably 0.5% by mass or less, more preferably 0.01 to 0.00%, when the total mass of the composition is 100% by mass. 4% by mass.

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

<Binder>
By adding a binder to the light guide plate composition according to the present embodiment, the adhesion between the light guide substrate and the light diffusion portion can be improved. Although it does not specifically limit as a binder, The binder as described in international publication 2005/071014 or Unexamined-Japanese-Patent No. 2013-93205 can be used.

2. Light Guide Plate The light guide plate according to the present embodiment is produced using the above-described light guide plate composition. Specifically, the light diffusing portion is produced by applying or printing the above-described light guide plate composition on a light guide substrate having a surface roughness Ra <1 nm.

FIG. 1 is a cross-sectional view showing a transmissive image display device including an embodiment of a light guide plate according to the present invention. The transmissive image display device 100 shown in FIG. 1 includes a surface light source device 20 and a transmissive image display unit 3.
It is mainly composed of 0. The surface light source device 20 is an edge light type including a light guide plate 1 including a light guide substrate 11 and a light diffusing unit 12, and a light source 3 provided on the side of the light guide plate 1 to supply light to the light guide plate 1. It is a surface light source device. In FIG. 1, the light diffusion portion 12 has a large number of dot shapes.

Light-guiding substrate 11 has a substantially rectangular parallelepiped shape, and an exit surface S1, opposite to the emission surface S2 of the exit surface S1, and four end surfaces _S3 1 to S3 ₄ intersecting the emitting surface S1 and the emission surface S2 Have. In the present embodiment, the four end surfaces S3 _{1 to} S3 ₄ are substantially orthogonal to the emission surface S1 and the emission surface S2.

  The light guide plate 1 further includes a plurality of light diffusing portions 12 provided on the exit surface S2 side. As shown in FIG. 2, the plurality of light diffusing units 12 are arranged on the emission surface S <b> 2 so as to be separated from each other. FIG. 2 is a plan view of the light guide substrate viewed from the exit surface S2 side. In FIG. 2, the light source 3 is also shown for convenience of explanation. In FIG. 2, the light diffusing parts 12 are arranged apart from each other. The number and arrangement pattern of the light diffusion portions 12 are adjusted so that uniform planar light is efficiently emitted from the emission surface S1 and, if necessary, the emission surface S2.

As shown in FIGS. 1 and 2, the light source 3 is disposed on a side of a pair of end faces S3 ₁ and S3 ₂ facing each other. As shown in FIG. 2, a plurality of point light sources may be arranged along two sides of the light guide substrate 11 that face each other, for example, among the four sides that form the rectangular emission surface S <b> 2.

In the above configuration, the light output from the light source 3 enters the light guide substrate 11 from the end faces S3 ₁ and S3 ₂ . The light incident on the light guide substrate 11 is irregularly reflected by the light diffusing unit 12, and the shape of the light diffusing unit 12 is adjusted so that the uniform planar light is efficiently emitted from the emitting surface S1 and the emitting surface S2. can do. For example, in the case of FIG. 1, the light emitted from the emission surface S <b> 1 is supplied to the transmissive image display unit 30.

  Hereinafter, the member which comprises a light-guide plate, and the manufacturing method of a light-guide plate are demonstrated in detail.

2.1. Light Guide Substrate The light guide plate 1 includes a light guide substrate 11. The surface roughness Ra of the light guide substrate 11 is sufficient if Ra <1 nm, and preferably Ra <0.5 nm, considering the light extraction efficiency from the emission surface S1 and the emission surface S2. In consideration of the adhesion between the light diffusion portion and the light guide 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 end surface of the light guide substrate 11 is such that light from the light source can be practically used as long as it is 2 μm or less in order to suppress scattering of light from the light source on the end surface of the light guide substrate 11. It can be incident inside.

  In addition, “surface roughness Ra” of the light guide substrate 11 in the present invention means “arithmetic average roughness” measured in accordance with JIS B0601-2001.

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

The thermal expansion coefficient of the glass substrate is preferably 120 × 10 ⁻⁷ / ° C. or less. When the thermal expansion coefficient exceeds the above range, the difference in dimensional change due to heat between the display panel and the light guide substrate tends to increase. Moreover, it is preferable that the strain point of a glass substrate is 550 degreeC or more. When the strain point is less than the above range, the heat resistance of the glass substrate tends to be lowered. For example, when a reflective film or a diffusion film is formed on the surface of the glass substrate at a high temperature, the glass substrate is likely to be thermally deformed. Here, the “strain point” can be measured based on JIS R3103.

2.1.1. A glass composition constituting the glass composition glass substrate, a SiO ₂ 40 to 70 wt%, the _Al 2 _{O 3} 2 to 25 _wt%, the B 2 _{O 3} 0 to 20 _{wt%, R} 2 O (R is Li , One or more of Na and K) 0 to 25% by mass, MgO 0 to 10% by mass, CaO 0 to 15% by mass, SrO 0 to 10% by mass, BaO 0 to 15% by mass, the ZnO 0 wt%, preferably contains a ZrO ₂ 0% by weight.

SiO ₂ is a component that serves as a network former of glass, and is a component that reduces a thermal expansion coefficient and reduces a dimensional change due to heat. It is a component that increases acid resistance and strain point. When the content of SiO ₂ is increased, the high temperature viscosity is increased, the meltability is lowered, and the devitrification blisters of cristobalite are liable to precipitate at the time of molding. On the other hand, when the content of SiO ₂ decreases, the coefficient of thermal expansion increases and the dimensional change due to heat tends to increase. In addition, acid resistance and strain point are likely to be lowered.

Al ₂ O ₃ is a component that lowers the thermal expansion coefficient and reduces dimensional changes due to heat. It also has the effect of increasing the strain point and suppressing the precipitation of devitrified cristobalite during molding. When the content of Al ₂ O ₃ is in the above range, the liquidus temperature rises and it becomes difficult to form a glass substrate. On the other hand, when the content of Al ₂ O ₃ decreases, the thermal expansion coefficient increases and the dimensional change due to heat tends to increase. In addition, the strain point tends to decrease.

B ₂ O ₃ is a component that acts as a flux, lowers the high temperature viscosity, and improves the meltability. Moreover, it is a component which reduces a thermal expansion coefficient and reduces the dimensional change by a heat | fever. When the content of B ₂ O ₃ is in the above range, a dimensional change due to heat can be suppressed, meltability can be improved, and workability can be improved.

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

  MgO is a component that improves the meltability by lowering only the high temperature viscosity without lowering the strain point. When the content of MgO is within the above range, it is possible to suppress devitrification deposits from being formed during molding.

  CaO is a component that improves the meltability by lowering only the high temperature viscosity without lowering the strain point. When the content of CaO is in the above range, it is possible to suppress devitrification deposits during the molding.

  SrO is a component that improves chemical resistance and devitrification resistance. When the SrO content is in the above range, the coefficient of thermal expansion can be reduced, and dimensional changes due to heat can be suppressed.

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

  ZnO is a component that improves meltability. When the content of ZnO is in the above range, devitrification resistance can be improved.

ZrO ₂ is a component that increases the strain point. When the content of ZrO ₂ is in the above range, it can be suppressed that devitrification bumps are precipitated during molding.

_{Incidentally, Fe 2 O 3, Cr 2} O 3, V 2 O 5, NiO, MnO 2, Nd 2 O 3, CeO 2, Er 2 content of the transition metal oxides, such as _{O 3} is 0.1 wt% It is preferable that When there is too much content of a transition metal oxide, light extraction efficiency may fall.

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

2.1.2. Manufacturing Method of Glass Substrate A glass substrate can be produced by an overflow down draw method, a slot down draw method, a float method, a roll out method, a redraw method, or the like. In the float process, a temperature difference and a composition difference between the front and back surfaces of the glass ribbon are likely to occur during molding. However, if the temperature control during the molding is strictly performed, the temperature difference and the composition difference can be reduced. In the overflow downdraw method, a temperature difference and a composition difference between the front and back surfaces of the glass ribbon are difficult to occur at the time of molding, and it becomes easy to mold a glass substrate that is unpolished and has a good surface quality.

  In addition, a glass substrate can also be applied to the glass substrate used for a display panel, and can also have the function of a light-guide substrate. In this way, the member configuration of the display device can be simplified.

2.2. Light Diffusing Section The light guide plate 1 according to the present embodiment includes a light diffusing section 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 with respect to the surface roughness Ra (nm) of the light guide substrate 11, and 300 <Dn It is more preferable that / Ra <4000. When the value of Dn / Ra is within the above range, it is possible to suppress the mixing of voids at the interface between the light guide substrate 11 and the light diffusing unit 12, and to improve the light extraction efficiency and realize uniform surface light emission. It is considered possible.

  In FIG. 2 described above, the light diffusing portion 12 has a plurality of substantially circular dot shapes and is spaced apart from each other. However, the light extraction efficiency required from the exit surface S1 and the exit surface S2 is necessary. The shape and the like can be adjusted in consideration of the above. The shape of the light diffusing unit 12 shown in FIG. 2 is for convenience of explanation, and can be adjusted in consideration of the light extraction efficiency required from the emission surface S1 and the emission surface S2.

  The light diffusion part 12 is produced using the above-mentioned composition for light guide plates. As a method for forming the light diffusion portion 12 on the light guide substrate 11, it can be produced by a screen printing method, an offset printing method, a spray coating method in which the light guide plate composition is sprayed from a nozzle, or the like. For example, the light guide plate can be produced by a method described in International Publication No. 2005/071014, JP2013-93205A, JP2012-178345A, or the like.

  As such a composition for light guide plates, a thermosetting or photocurable composition for light guide plates is preferable. In order to effectively suppress the distortion of the light guide substrate due to the heat treatment, it is more preferable to produce a light diffusion portion using a photocurable light guide plate composition. The light guide plate composition for forming the light diffusing section 12 is a photocurable light guide plate composition, which is a radiation curable light guide plate composition containing a photopolymerizable component and a photopolymerization initiator. It is preferable that

  The area of the light diffusion portion 12 is preferably 5% or more and 95% or less with respect to 100% of the area of the light guide substrate 11. As the distance from the light source increases, the ratio of the flat area occupied by the light diffusion portion 12 on the coated surface of the light guide substrate 11 and the application area of the light guide plate composition or the application area of the light guide plate composition and the front light guide substrate 11 It is preferable that the ratio of the coating area to the area of the coating surface is increased. Thereby, the brightness | luminance of a light-guide plate can be made substantially uniform.

2.3. Light source 3, as shown in FIGS. 1 and 2, is located on a side of the end surface S3 ₁ and S3 _2. The light source 3 may be a linear light source such as a cold cathode fluorescent lamp (CCFL), but is preferably a point light source such as an LED. In this case, as shown in FIG. 2, the light diffusing portion is arranged such that a plurality of point light sources are arranged along two opposite sides of the four sides constituting the rectangular emission surface S <b> 2 of the light guide plate 11. 12 and the light source 3 are preferably combined.

In the above structure, the light output from the light source 3 is incident from the end surface S3 ₁ and S3 ₂ the light guide plate 11. The light incident on the light guide plate 11 is emitted from the emission surfaces S <b> 1 and S <b> 2 by irregular reflection and diffusion in the light diffusion unit 12. Light emitted from the emission surfaces S1 and S2 is supplied to the transmissive image display unit 30 and the like. The number and arrangement pattern of the light diffusion portions 12 can be adjusted in a timely manner so that uniform planar light is efficiently emitted from the emission surface.

2.4. Transmission Image Display Unit As shown in FIG. 1, the transmission image display unit 30 is disposed opposite to the light guide plate 1 on the light emission surface S1 side of the light guide plate 1, and light emitted from the light emission surface S1 is transmitted. The image display unit 30 is illuminated. As the transmissive image display unit 30, for example, a liquid crystal display unit having a liquid crystal cell can be used.

3. EXAMPLES Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. “Part” and “%” in Examples and Comparative Examples are based on mass unless otherwise specified.

3.1. Production of light diffusing particles (A) 3.1.1. Preparation of hollow particles 1 In a reaction vessel having a capacity of 2 liters, 194 parts of water, 9 parts of methyl methacrylate, 1 part of methacrylic acid, 0.92 parts of octyl thioglycolate as a molecular weight regulator, sodium dodecylbenzenesulfonate as an emulsifier 04 parts were added. Meanwhile, 71 parts of methyl methacrylate, 19 parts of methacrylic acid, 0.5 part of octylthioglycolate, 0.5 part of sodium dodecylbenzenesulfonate and 45 parts of water are mixed and stirred to prepare an aqueous dispersion of the monomer mixture. did.

  The reaction vessel was heated to a temperature of 85 ° C. while stirring, and 6 parts of a 5% aqueous sodium persulfate solution was added as a polymerization initiator. Immediately thereafter, an aqueous dispersion of the monomer mixture was continuously added over 4 hours while maintaining the temperature at 90 ° C. while stirring the reaction vessel. Further, aging was performed for 2 hours to obtain an aqueous dispersion (seed content 29.3%) of seed particles A having a particle size of 0.200 μm.

  A reaction vessel having a capacity of 2 liters was charged with 143 parts of water, 10 parts of an aqueous dispersion of the seed particles A (34 parts as an aqueous dispersion), and 1.2 parts of an 80% aqueous acrylic acid solution. Meanwhile, 77.2 parts of styrene, 0.8 parts of divinylbenzene (m, p-mixture, purity 81%), 1.3 parts of 80% aqueous acrylic acid solution, 0.5 parts of sodium dodecylbenzenesulfonate and water 46 An aqueous dispersion of the monomer mixture was prepared by mixing and stirring 7 parts.

  The reaction vessel was heated to 80 ° C. with stirring, and 8 parts of 5% aqueous sodium persulfate solution was added as a polymerization initiator. While maintaining the reaction vessel at a temperature of 80 ° C., the aqueous dispersion of the monomer mixture was continuously added over 2 hours. Immediately after all of the above monomer aqueous dispersion was charged into the reaction vessel, 19.6 parts of styrene, 0.4 part of divinylbenzene (m, p-mixture, purity 81%), and 20 parts of 6% ammonium hydroxide were batched. I put it in. Thereafter, the temperature is raised to 85 ° C., and the mixture is aged and stirred for 2 hours. An aqueous dispersion of spherical hollow seed particles B having a single pore having a particle size of 0.487 μm, an inner pore size of 0.312 μm, and a volume porosity of 26%. (Solid content 30.9%) was obtained.

  In a reaction vessel having a capacity of 2 liters, 569 parts of water, 100 parts of an aqueous dispersion of the hollow seed particles B (324 parts as an aqueous dispersion), 20 parts of styrene, divinylbenzene (m, p-mixture, purity) 81%) 80 parts and 4 parts of sodium dodecylbenzenesulfonate were added. The reaction vessel was kept at 40 ° C. for 3 hours with stirring, and then heated to 65 ° C., and 6 parts of a 5% aqueous solution of sodium persulfate was added as a polymerization initiator. The reaction vessel was further heated and kept stirring at 80 ° C., and 1 hour after reaching 80 ° C., 2 parts of a 5% aqueous solution of sodium persulfate was added, and stirring was further continued for 1 hour. Thereafter, the temperature was raised to 85 ° C., and after 1 hour, 2 parts of a 5% aqueous solution of sodium persulfate was added, and the mixture was further aged and stirred for 1 hour. Thereafter, the reaction vessel is cooled to 40 ° C., and the contents are filtered using a nylon mesh having an opening of 50 μm, and further subjected to pressure filtration using a polypropylene cartridge filter having a filtration accuracy of 10 μm. A dispersion (solid content 20.5%) was obtained. The obtained aqueous dispersion was dried by a spray drying method (temperature 110 to 220 ° C.) using a mini spray dryer B-290 manufactured by Nihon Büch, and the particle diameter was 0.609 μm, the inner pore diameter was 0.381 μm, and the volume was empty. A spherical hollow particle 1 having a single hole having a porosity of 24% was obtained.

  Further, the major axis (Rmax) and minor axis (Rmin) of any 20 hollow particles 1 are measured with a transmission electron microscope (manufactured by Hitachi High-Technologies Corporation, model “H-7650”), and the average value is calculated. As a result, the major axis was 0.615 μm, the minor axis was 0.604 μm, and the ratio of the major axis to the minor axis (Rmax / Rmin) was 1.02.

In addition, using the aqueous dispersion of hollow particles 1 obtained above as a sample, using a particle size distribution measuring apparatus (model “ELSZ-1000ZS” manufactured by Otsuka Electronics Co., Ltd.) having a dynamic light scattering method as a measurement principle, When the number average particle size (Dn) and the standard deviation (σ) of the particle size distribution of the hollow particles 1 were determined, the number average particle size (Dn) was 0.609 μm and the standard deviation (σ) was 0.034 μm. . From these values, the particle variation coefficient (CV value) was calculated by the following formula (1). As a result, the CV value was 0.056.
CV value = standard deviation of particle size distribution (σ) / number average particle size (Dn) (1)

3.1.2. Preparation of core-shell particles In a reaction vessel with a capacity of 2 liters, 947 parts of water, 1.6 parts of the aqueous dispersion of seed particles A (5.5 parts in the case of an aqueous dispersion), sodium dodecylbenzenesulfonate 0. 5 parts were added and heated to a temperature of 85 ° C. while stirring, and 10 parts of a 3% aqueous potassium persulfate solution was added as a polymerization initiator. While maintaining the temperature at 85 ° C., a monomer mixture consisting of 80 parts of styrene and 20 parts of divinylbenzene (m, p-mixture, purity 81%) was continuously added over 3 hours. After aging for 2 hours, the reaction vessel was cooled to 40 ° C., and the contents were filtered using a nylon mesh with an opening of 50 μm, and further filtered under pressure using a polypropylene cartridge filter with a filtration accuracy of 10 μm. To obtain an aqueous dispersion of solid particles 1 (solid content 10.0%).

  Next, 2 parts of bis (3,5,5-trimethylhexanoyl) peroxide (trade name “Perroyl (registered trademark) 355”, manufactured by NOF Corporation, water solubility: 0.01%), dodecylbenzenesulfonic acid After stirring and emulsifying 0.1 part of sodium and 17.9 parts of water, the mixture was further finely divided by an ultrasonic homogenizer (manufactured by SMT Co., Ltd.) to obtain an aqueous dispersion of a polymerization initiator. To the prepared aqueous dispersion of the polymerization initiator, 15 parts of the aqueous dispersion of the solid particles 1 as core particles was added as a solid content (150 parts as an aqueous dispersion) and stirred for 16 hours. Thereafter, 680 parts of water, 90 parts of methyl methacrylate, 10 parts of ethylene glycol dimethacrylate, and 50 parts of 10% aqueous solution of Jonkrill (registered trademark) 62 manufactured by BASF were added and stirred for 3 hours while maintaining the temperature at 40 ° C. Further, by stirring for 3 hours while maintaining the temperature at 80 ° C., core-shell particles in which the surface of the dense particles 1 was polymer-coated were synthesized. Thereafter, the reaction vessel is cooled to 40 ° C., and the content is filtered using a nylon mesh having an opening of 50 μm, and further filtered under pressure using a polypropylene cartridge filter having a filtration accuracy of 10 μm, whereby aqueous dispersion of core-shell particles is performed. A body (solid content 12.2%) was obtained. The obtained aqueous dispersion was dried by a spray drying method (temperature 110 to 220 ° C.) using a mini spray dryer B-290 manufactured by Nihon Büch to obtain core-shell particles having a particle size of 1.54 μm.

  The major axis (Rmax) and minor axis (Rmin) of the core-shell particles were measured in the same manner as the hollow particles 1, and the average values were calculated. The major axis was 1.56 μm and the minor axis was 1.51 μm. The ratio (Rmax / Rmin) to 1.03 was 1.03. Further, when the number average particle size, standard deviation, and particle variation coefficient of the core-shell particles were determined in the same manner as the hollow particles 1, the number average particle size was 1.54 μm, the standard deviation was 0.154 μm, and the particle variation coefficient was 0.1. Met.

3.1.3. Preparation of irregularly shaped particles In a reaction vessel having a capacity of 2 liters, 947 parts of water, 1.6 parts of the aqueous dispersion of seed particles A (solid content of 5.5 parts), 80 parts of styrene, divinylbenzene ( m, p-mixture, purity 81%) 15 parts, 2-hydroxyethyl methacrylate 5 parts and sodium dodecylbenzenesulfonate 0.5 part were added and heated to 85 ° C. with stirring to give 3 polymerization initiators. A 10% aqueous solution of potassium persulfate was added. By aging for 6 hours while maintaining the temperature at 85 ° C., an aqueous dispersion (solid content 10.0%) of the first polymer particles having a particle size of 0.809 μm was obtained.

  2 parts of bis (3,5,5-trimethylhexanoyl) peroxide (trade name “Perroyl (registered trademark) 355”, manufactured by NOF Corporation, water solubility: 0.01%), sodium dodecylbenzenesulfonate 0 .1 part and 17.9 parts of water were stirred and emulsified, and then further finely divided by an ultrasonic homogenizer (manufactured by SMT Co., Ltd.) to obtain an aqueous dispersion of a polymerization initiator. To the prepared aqueous dispersion of the polymerization initiator, 15 parts of the aqueous dispersion of the first polymer particles (150 parts of the aqueous dispersion) as a solid content was added and stirred for 16 hours. Thereafter, 680 parts of water, 90 parts of methyl methacrylate, 10 parts of ethylene glycol dimethacrylate, and 50 parts of 10% aqueous solution of Jonkrill (registered trademark) 62 manufactured by BASF were added and stirred for 3 hours while maintaining the temperature at 40 ° C. Further, the shaped particles were synthesized by stirring for 3 hours while maintaining the temperature at 80 ° C. Thereafter, the reaction vessel is cooled to 40 ° C., and the content is filtered using a nylon mesh having an opening of 50 μm, and further filtered under pressure using a polypropylene cartridge filter having a filtration accuracy of 10 μm, whereby the aqueous dispersion of irregular shaped particles is performed. A body (solid content 12.2%) was obtained. The obtained aqueous dispersion was dried by a spray drying method (temperature 110 to 220 ° C.) using a mini spray dryer B-290 manufactured by Nihon Büch to obtain irregular shaped particles having a particle size of 1.67 μm.

  Similar to the hollow particles 1, the major axis (Rmax) and minor axis (Rmin) of the irregularly shaped particles were measured, and the average values were calculated. The major axis was 1.81 μm and the minor axis was 1.53 μm. The ratio (Rmax / Rmin) to 1.18 was 1.18. Further, the number average particle size, standard deviation, and particle variation coefficient of the irregularly shaped particles were determined in the same manner as the hollow particles 1, and the number average particle size was 1.67 μm, the standard deviation was 0.147 μm, and the particle variation coefficient was 0.088. Met.

3.1.4. Preparation of calcium carbonate particles A Calcium carbonate purchased from Wako Pure Chemical Industries, Ltd. was pulverized in an agate mortar, further classified with a water sieve, and then spray dried using a mini spray dryer B-290 manufactured by Nihon Büch Light diffusing particles having a particle major axis / minor axis ratio shown in Table 1 were prepared by drying using a method (temperature: 110 to 220 ° C.). In addition, an aqueous dispersion in which the obtained calcium carbonate particles A are dispersed in water using an ultrasonic disperser is used as a sample, and the number average particle diameter, standard deviation, and particles of the calcium carbonate particles A are the same as the hollow particles 1. When the coefficient of variation was determined, the number average particle size was 2.23 μm, the standard deviation was 0.443 μm, and the particle variation coefficient was 0.199.

3.1.5. Preparation of barium sulfate particles A Barium sulfate purchased from Wako Pure Chemical Industries, Ltd. was ground in an agate mortar, further classified with a water sieve, and then spray dried using a mini spray dryer B-290 manufactured by Nihon Büch. Light diffusing particles having a particle major axis / minor axis ratio shown in Table 1 were prepared by drying using a method (temperature: 110 to 220 ° C.). The obtained barium sulfate particles A were dispersed in water using an ultrasonic disperser as a sample. Like the hollow particles 1, the number average particle diameter, standard deviation, and particles of the barium sulfate particles A were measured. When the coefficient of variation was determined, the number average particle size was 1.97 μm, the standard deviation was 0.355 μm, and the particle variation coefficient was 0.180.

3.1.6. Preparation of Titanium Dioxide Particles A Titanium dioxide purchased from Wako Pure Chemical Industries, Ltd. is pulverized in an agate mortar, further classified with a water sieve, and then spray dried using a mini spray dryer B-290 manufactured by Nihon Büch. Light diffusing particles having a particle major axis / minor axis ratio shown in Table 1 were prepared by drying using a method (temperature: 110 to 220 ° C.). In addition, an aqueous dispersion in which the obtained titanium dioxide particles A are dispersed in water using an ultrasonic disperser is used as a sample, and the number average particle diameter, standard deviation, particles of the titanium dioxide particles A are the same as the hollow particles 1. When the coefficient of variation was determined, the number average particle size was 2.67 μm, the standard deviation was 0.400 μm, and the particle variation coefficient was 0.150.

3.2. Example 1
20 parts by mass of hollow particles 1 prepared above, 33.1 parts by mass of bisphenol A epoxy diacrylate (manufactured by Arkema Co., Ltd., trade name “CN104”), 2-hydroxy-3-phenoxypropyl acrylate (Daiichi Kogyo Seiyaku ( Co., Ltd., trade name “New Frontier PGA”) 40.1 parts by mass, bis (2- (meth) acryloyloxyethyl) phosphate ester (manufactured by Nippon Kayaku Co., Ltd., trade name “KAYAMER PM-2”) 0.4 parts by mass, 6.3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF Japan Ltd., trade name “Irgacure 184”), 0.08 parts by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) , 2-methyl-4-isothiazolin-3-one (manufactured by Wako Pure Chemical Industries, Ltd.) 0.04 parts by mass, Moisture in the composition content was adjusted to 0.4 parts by weight. Furthermore, it knead | mixed using the planetary-type stirring apparatus (the Kurashiki Boseki Co., Ltd. make, model "KK-50S"), and prepared the composition for light-guide plates containing the hollow particle 1 as a light-diffusion particle (A).

Next, a glass light guide substrate (manufactured by Nippon Electric Glass Co., Ltd., product name “OA-10G”, glass substrate with surface roughness Ra = 0.5 nm manufactured by the overflow method) is placed on the work stage. The light guide plate composition obtained above was screen-printed in a dot shape from above and then cured by ultraviolet irradiation to produce a light guide plate on which a light diffusion portion was formed.

  In addition, the application | coating conditions of the composition for light-guide plates, the irradiation conditions of an ultraviolet-ray, and an evaluation method are as follows.

<Application conditions>
The dots were screen printed according to the following conditions. The dot diameter was 300 μm, the dot film thickness was 15 μm, and the dot pattern was a pitch gradation design with a pitch of 500 to 2000 μm.
-Dimensions of light guide substrate: length (length in light guide direction) 718 mm, width 413 mm, thickness 2 mm
・ Coating surface: Output surface (surface of the light guide substrate)
-Application means: screen printing-Mesh: 420 mesh / inch-Squeegee angle: 50 °
・ Squeegee speed: 65mm / s
・ Squeegee pressure: 0.198 kgf / cm ²
・ Clearance: 1.1mm

<Ultraviolet irradiation conditions>
・ Lamp: Super high pressure mercury lamp (irradiation wavelength 280nm to 500nm)
・ Irradiation amount: 550 mJ / cm ² (365 nm)

<Evaluation method>
(1) Evaluation of curability After the composition for a light guide plate is cured by ultraviolet irradiation as described above, the formed light diffusion portion is palpated, and when tack can be recognized, it is determined that the curing is poor and “× When the tack was not recognized, it was judged that the curability was good and indicated as “◯” in the table.

(2) Evaluation of luminance unevenness and chromaticity unevenness of the light guide plate A light source in which white LEDs are linearly arranged is installed at both ends of the produced light guide plate, a white diffuse reflection sheet on the back side of the light guide plate, A light diffusion film was laminated on the coated surface to prepare a sidelight type backlight. When the side-light type backlight is visually observed from a position 2 m away from the front, if the brightness is uniform over the entire surface and uneven brightness cannot be recognized, and it can be judged to be very good, “◎”, slight brightness Unevenness is recognized, but it can be judged that it can be used for applications that do not require strictly uniform brightness. ”In the table.

  Furthermore, when the side-light type backlight is visually observed from a position 2 m away from the front, if the chromaticity unevenness cannot be recognized and the color development is white and it can be determined that the color is very good, “◎” "○" when it can be judged that it can be used for applications where strict white light emission is not required, but it is judged to be defective when the in-plane chromaticity unevenness is large and difficult to use. ”In the table.

(3) Storage stability The light guide plate composition prepared above is stored in a light-shielding environment at room temperature, and a light guide plate is produced by the method every month, and the luminance unevenness evaluation and chromaticity unevenness evaluation are performed. Thus, the storage stability of the light guide plate composition was evaluated. When the brightness unevenness and chromaticity unevenness of the light guide plate are the same as when using the composition for the light guide plate immediately after preparation, “◎”, a slight change is seen, but it can be used as a light guide plate In the table, “○” indicates that there is no influence, and “×” indicates that the use is different.

3.3. Example 2, Comparative Examples 1-2
The type and content of the radical scavenger (C) are as shown in Table 1, and a light guide plate composition was prepared and evaluated in the same manner as in Example 1 except that the amount of each material used was finely adjusted. went.

3.4. Example 3
10 parts by mass of the core-shell particles prepared above, 36.6 parts by mass of bisphenol A epoxy diacrylate (manufactured by Arkema Co., Ltd., trade name “CN104”), 2-hydroxy-3-phenoxypropyl acrylate (Daiichi Kogyo Seiyaku Co., Ltd.) ), Trade name “New Frontier PGA”) 44.4 parts by mass, bis (2- (meth) acryloyloxyethyl) phosphate ester (manufactured by Nippon Kayaku Co., Ltd., trade name “KAYAMER PM-2”) 0 .44 parts by mass, 7.0 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF Japan Ltd., trade name “Irgacure 184”), 0.05 parts by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.), 0.1 parts by mass of 2-methyl-4-isothiazolin-3-one (Wako Pure Chemical Industries, Ltd.) Furthermore, it prepared so that the water | moisture content in a composition might be 1.5 mass parts. Furthermore, the composition for light-guide plates which contains a core-shell particle as a light-diffusion particle (A) by kneading using a planetary-type stirring apparatus (the model "KK-50S" by Kurashiki Boseki Co., Ltd.), Example Evaluation was performed in the same manner as in Example 1.

3.5. Example 4
30 parts by mass of the irregularly shaped particles prepared above, 28.8 parts by mass of bisphenol A epoxy diacrylate (manufactured by Arkema Co., Ltd., trade name “CN104”), 2-hydroxy-3-phenoxypropyl acrylate (Daiichi Kogyo Seiyaku Co., Ltd.) ), Trade name “New Frontier PGA”) 34.8 parts by mass, bis (2- (meth) acryloyloxyethyl) phosphate ester (manufactured by Nippon Kayaku Co., Ltd., trade name “KAYAMER PM-2”) 0 .35 parts by mass, 1.45 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF Japan Ltd., trade name “Irgacure 184”), 0.1 parts by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.), 0.1 part by mass of 2-methyl-4-isothiazolin-3-one (manufactured by Wako Pure Chemical Industries, Ltd.) is mixed and further assembled It prepared so that the water | moisture content in a component might be 0.4 mass part. Further, a light guide plate composition containing irregularly shaped particles as light diffusing particles (A) was prepared by kneading using a planetary stirring device (manufactured by Kurashiki Boseki Co., Ltd., model “KK-50S”). Evaluation was performed in the same manner as in Example 1.

3.6. Example 5
9 parts by mass of calcium carbonate particles A prepared above, 37.6 parts by mass of bisphenol A epoxy diacrylate (manufactured by Arkema Co., Ltd., trade name “CN104”), 2-hydroxy-3-phenoxypropyl acrylate (Daiichi Kogyo Seiyaku ( Co., Ltd., trade name “New Frontier PGA”) 45.6 parts by mass, bis (2- (meth) acryloyloxyethyl) phosphate ester (manufactured by Nippon Kayaku Co., Ltd., trade name “KAYAMER PM-2”) 0.45 parts by mass, 7.17 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF Japan Ltd., trade name “Irgacure 184”), 0.06 parts by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) , 0.02 parts by mass of 2-methyl-4-isothiazolin-3-one (Wako Pure Chemical Industries, Ltd.) In addition, the water content in the composition was adjusted to 0.02 parts by mass. Further, a light guide plate composition containing calcium carbonate particles A as the light diffusion particles (A) is prepared by kneading using a planetary stirring device (Kurashiki Boseki Co., Ltd., model “KK-50S”), Evaluation was performed in the same manner as in Example 1.

3.7. Example 6
Barium sulfate particles A9 parts by mass produced above, bisphenol A epoxy diacrylate (manufactured by Arkema Co., Ltd., trade name “CN104”) 37.6 parts by mass, 2-hydroxy-3-phenoxypropyl acrylate (Daiichi Kogyo Seiyaku ( Co., Ltd., trade name “New Frontier PGA”) 45.6 parts by mass, bis (2- (meth) acryloyloxyethyl) phosphate ester (manufactured by Nippon Kayaku Co., Ltd., trade name “KAYAMER PM-2”) 0.45 parts by mass, 7.17 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF Japan Ltd., trade name “Irgacure 184”), 0.05 parts by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) , 0.03 parts by mass of 2-methyl-4-isothiazolin-3-one (manufactured by Wako Pure Chemical Industries, Ltd.) Furthermore, the water content in the composition was adjusted to 0.03 parts by mass. Furthermore, a composition for a light guide plate containing barium sulfate particles A as light diffusion particles (A) is prepared by kneading using a planetary stirring device (Kurashiki Boseki Co., Ltd., model “KK-50S”), Evaluation was performed in the same manner as in Example 1.

3.8. Example 7
9 parts by mass of titanium dioxide particles A produced above, 37.6 parts by mass of bisphenol A epoxy diacrylate (manufactured by Arkema Co., Ltd., trade name “CN104”), 2-hydroxy-3-phenoxypropyl acrylate (Daiichi Kogyo Seiyaku ( Co., Ltd., trade name “New Frontier PGA”) 45.6 parts by mass, bis (2- (meth) acryloyloxyethyl) phosphate ester (manufactured by Nippon Kayaku Co., Ltd., trade name “KAYAMER PM-2”) 0.45 parts by mass, 7.17 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF Japan Ltd., trade name “Irgacure 184”), 0.3 parts by mass of hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) , 0.03 parts by mass of 2-methyl-4-isothiazolin-3-one (Wako Pure Chemical Industries, Ltd.) Furthermore, the water content in the composition was adjusted to 0.04 parts by mass. Furthermore, a composition for a light guide plate containing titanium dioxide particles A as light diffusion particles (A) is prepared by kneading using a planetary stirring device (manufactured by Kurashiki Boseki Co., Ltd., model “KK-50S”), Evaluation was performed in the same manner as in Example 1.

3.9. Evaluation Results Table 1 below shows the composition, physical properties, and evaluation results of the light guide plate compositions used in the examples and comparative examples.

In addition, each material described in Table 1 used the goods or compounds described below.
Dispersion medium (B)
B1: Bisphenol A epoxy diacrylate, manufactured by Arkema Co., Ltd., trade name “CN104”
B2: 2-hydroxy-3-phenoxypropyl acrylate, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name “New Frontier PGA”
Radical scavenger (C)
C1: Hydroquinone monomethyl ether, manufactured by Wako Pure Chemical Industries, Ltd. C2: N-nitrosophenylhydroxylamine aluminum salt, manufactured by Wako Pure Chemical Industries, Ltd.
Photopolymerization initiator : 1-hydroxycyclohexyl phenyl ketone, manufactured by BASF Japan Ltd., trade name “Irgacure 184”
Phosphate ester : Bis (2- (meth) acryloyloxyethyl) phosphate ester, Nippon Kayaku Co., Ltd., trade name “KAYAMER PM-2”)
Isothiazoline-based compound : 2-methyl-4-isothiazolin-3-one, manufactured by Wako Pure Chemical Industries, Ltd.
Water : Ion exchange water

  It turns out that the composition for light-guide plates of Examples 1-7 has favorable sclerosis | hardenability and is excellent in storage stability. Moreover, since the light-guide plate produced using the composition for light-guide plates containing the radical scavenger (C) of Examples 1-7 in a predetermined ratio can effectively suppress luminance unevenness and chromaticity unevenness, the light-guide plate It can be seen that the surface light emission uniformity is excellent, and good light emission characteristics are exhibited.

  The present invention is not limited to the above embodiment, and various modifications can be made. The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). The present invention also includes a configuration in which a non-essential part of the configuration described in the above embodiment is replaced with another configuration. Furthermore, the present invention includes a configuration that achieves the same effect as the configuration described in the above embodiment or a configuration that can achieve the same object. Furthermore, the present invention includes a configuration obtained by adding a known technique to the configuration described in the above embodiment.

DESCRIPTION OF SYMBOLS 1 ... Light guide plate, 3 ... Light source, 11 ... Light guide board | substrate, 12 ... Light-diffusion part, 20 ... Surface light source device, 30 ... Transmission-type image display part, 40a * 40b * 40c ... Light-diffusion particle | grains, 50a * 50b * 50c 50d, 50e, 50f ... irregularly shaped particles, 52a, 52b, 52c, 52d, 52e, 52f ... first light diffusing particles, 54a, 54b, 54c, 54d, 54e, 54f ... second light diffusing particles, 100 ... Transmission type image display device (liquid crystal display device), S1, S2 ... (light guide substrate) exit surface, S3 ₁ , S3 ₂ , S3 ₃ , S3 ₄ (end of light guide substrate)

Claims (6)

Light diffusing particles (A);
A dispersion medium (B);
A radical scavenger (C),
When the content of the light diffusing particles (A) is Ma parts by mass and the content of the radical scavenger (C) is Mc parts by mass, the ratio Ma / Mc between them is 20 to 500. Composition.   The composition for light-guide plates of Claim 1 containing a photopolymerizable component as said dispersion medium (B).   Furthermore, the composition for light-guide plates of Claim 1 or Claim 2 containing an isothiazoline type compound.   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 is 0.01 to 0.2. The composition for light-guide plates of description.   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 composition for light-guide plates of description. The light-guide plate produced using the composition for light-guide plates as described in any one of Claims 1 thru | or 5.

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