JP5967462B2 - Louver seat - Google Patents

Description

  The present invention relates to a louver sheet, and more specifically, a louver sheet comprising a light transmission part having a plurality of grooves arranged in parallel on the surface, and a light absorption part formed in the groove of the light transmission part. About.

  In a liquid crystal display device, it is usually preferred that the viewing angle is wide so that a good image can be obtained from any position of the observer. On the other hand, for example, when working on a commuter train or in a liquid crystal display device installed in a public place such as an ATM, it may be difficult to see the screen from people around you. There is a demand for a peeping prevention function for protecting privacy so that it can be seen only by an observer of the display device and cannot be seen by others. In car-mounted liquid crystal display devices such as car navigation systems, the screen of the liquid crystal display device is reflected on the window glass at night and the like, and the phenomenon of blocking the field of view occurs. Control of the light emission angle is desired.

  In response to such demands, for example, a louver-type optical sheet having a structure in which light transmission layers and light shielding layers are alternately arranged has been proposed. As a light shielding layer, carbon black is used as a material constituting the light transmission layer. And a mixture of fillers such as carbon fiber is disclosed (for example, see Patent Document 1).

  On the other hand, the louver-type optical sheet as described above simply cuts the image light in the oblique direction. Therefore, depending on the type of the display device, the diffusion light source of the image light that should reach the observer is reduced. As a result, the brightness of the display screen may be reduced.

  In order to solve the above problem, it has been proposed to install a louver sheet on an optical sheet that can block external light to improve contrast and reduce the occurrence of double images. Various types of louver sheets have been proposed. For example, it is proposed to have a light transmission part in which a plurality of grooves are arranged on the surface, and a light absorption part formed by filling the groove with a material having a refractive index lower than that of the light transmission part and a carbon pigment or the like. (For example, see Patent Document 2).

JP 2006-119365 A JP 2006-85050 A

  In the conventional optical sheet, a transparent resin layer, an adhesive layer, and the like are provided between the louver sheet and a functional layer such as an antireflection layer provided on the image light emission side. The present inventors have found that the cost can be reduced and the manufacturing process can be simplified by reducing the transparent resin layer and the adhesive layer as much as possible. However, as a result of removing the adhesive layer having an ultraviolet blocking effect, a new problem has been found that foreign matter is generated in the light transmission part due to the influence of external light (mainly ultraviolet light) reaching the light transmission part of the louver sheet. .

  The present invention has been made in view of the above-mentioned background art and newly discovered problems, and an object thereof is to provide a louver sheet with improved light resistance in which no foreign matter is generated in the light transmitting portion by light irradiation. There is to do. Moreover, the objective of this invention is providing the optical sheet provided with the louver sheet which improved such light resistance.

  As a result of intensive studies to solve the above problems, the present inventors have formed a light transmission part comprising a photocurable prepolymer polymerized using a bismuth compound as a catalyst, and an acylphosphine oxide photopolymerization initiator. It has been found that the above-mentioned problems can be solved by curing the composition for use and forming the light transmission part of the louver sheet. The present invention has been completed based on such findings.

That is, according to one aspect of the present invention,
A louver sheet comprising a light transmission part having a plurality of grooves arranged in parallel on the surface, and a light absorption part formed in the groove of the light transmission part,
The light transmitting part is formed by curing a light transmitting part forming composition comprising a photocurable prepolymer polymerized using a bismuth compound as a catalyst and an acyl phosphine oxide photopolymerization initiator. A louver sheet is provided.

  In the embodiment of the present invention, the acyl phosphine oxide photopolymerization initiator is preferably monoacyl phosphine oxide and / or bisacyl phosphine oxide.

  In an embodiment of the present invention, the monoacylphosphine oxide is 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, It is preferably at least one selected from the group consisting of 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, and pivaloylphenylphosphinic acid isopropyl ester.

  In an embodiment of the present invention, the bisacylphosphine oxide is bis- (2,6-dichlorobenzoyl) phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide. Bis- (2,6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis- (2,6-dimethoxybenzoyl) phenylphosphine Fin oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,5-dimethylphenylphosphine oxide, bis- ( 2,4,6-trimethylbenzoyl) E sulfonyl phosphine oxide, and (2,5,6-trimethylbenzoyl) -2,4,4 is preferably at least one selected from the group consisting of trimethyl pentyl phosphine oxide.

  In the embodiment of the present invention, the photocurable prepolymer is preferably a urethane acrylate oligomer.

  In the aspect of the present invention, the urethane acrylate oligomer is preferably formed by polymerizing a polyisocyanate compound and a polyol compound using the bismuth compound as a catalyst.

  In the embodiment of the present invention, the bismuth compound is preferably bismuth organic carboxylate.

  In an embodiment of the present invention, the bismuth organic carboxylate is bismuth triacetate, bismuth tripropionate, bismuth triheptanoate, bismuth trioctanoate, bismuth tri (2-ethylhexanoate), bismuth tri (neodecanoate). ), Bismuth reversate, bismuth trilaurate, bismuth trioleate, and bismuth tristearate.

According to another aspect of the invention,
With the above louver sheet,
An optical sheet comprising, on the image light emitting side of the louver sheet, at least one functional layer selected from the group consisting of an antiglare layer, an antireflection layer, an antistatic layer, a hard coat layer, and an antifouling layer Is provided.

According to another aspect of the invention,
An image display device comprising the above optical sheet and a display unit is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the louver sheet which improved the light resistance which does not generate | occur | produce a foreign material in a light transmissive part by light irradiation can be provided. Moreover, by using such a louver sheet with improved light resistance as the optical sheet, it is possible to reduce the transparent resin layer and the adhesive layer, thereby reducing costs and simplifying the manufacturing process.

It is the cross-sectional schematic which showed one Embodiment of the louver sheet | seat by this invention. It is the schematic diagram which showed one Embodiment of the formation process of the light transmissive part by this invention. It is the cross-sectional schematic which showed one Embodiment of the light transmissive part by this invention. It is the cross-sectional schematic which showed one Embodiment of the optical sheet by this invention. 1 is a schematic cross-sectional view showing an embodiment of an image display device according to the present invention. 2 is a photomicrograph after a light resistance test of a louver sheet produced in Example 1. FIG. 4 is a photomicrograph of a louver sheet produced in Comparative Example 1 after a light resistance test.

Louver sheet The louver sheet according to the present invention comprises a light transmission part having a plurality of grooves arranged on the surface thereof, and a light absorption part formed in the groove of the light transmission part. The louver sheet may further include a base material, and the light transmission part may be formed on the base material.

  The louver sheet according to the present invention preferably does not include an ultraviolet absorbing layer on the image light exit side of the light transmitting portion. This is because the louver sheet according to the present invention has sufficient light resistance even when the ultraviolet absorbing layer is removed, and by removing the ultraviolet absorbing layer, the cost can be reduced and the manufacturing process can be simplified. .

  For example, the louver sheet 3 shown in FIG. 1 is formed in the base 1, the light transmitting portion 2 formed on the base 1 and having a plurality of grooves arranged in parallel on the surface, and the light transmitting portion in the groove. The light absorption part 4 was provided.

  The light absorption unit 4 has a refractive index that is the same as or smaller than the refractive index of the light transmission unit 2. Since the refractive indexes of the light transmission part 2 and the light absorption part 4 are as described above, the image light from the light source incident on the light transmission part 2 under a predetermined condition is transmitted to the light absorption part 4 and the light transmission part 2. It is possible to provide a bright image to the observer by appropriately reflecting at the boundary surface. Further, since a part of the external light from the observer side is absorbed, the contrast is improved. In addition, stray light that is incident on the inner side of the light absorbing unit 4 without being reflected at the boundary surface between the light transmitting unit 2 and the light absorbing unit 4 is absorbed by the light absorbing material in the light absorbing unit 4. In addition, since the external light from the observer side incident at a predetermined angle can be appropriately absorbed, the contrast can also be improved. In addition, it does not restrict | limit that the light absorption part 4 is larger than the refractive index of the light transmissive part 2. FIG.

  In addition, two louver sheets may be overlapped, and in that case, the louver sheets may have different structures. For example, the first louver sheet and the second louver sheet change the width, pitch, depth, and shape of the light absorption part, change the direction of the light absorption part in the thickness direction, It is possible to change the bias angle of the absorber (the inclination angle of the light absorber relative to the horizontal direction). Moreover, the material (the kind of resin and the density | concentration of a light absorption particle) which forms a light absorption part can also be changed. For example, the first layer is designed to cut off external light efficiently and focus on improving the contrast, and the second layer is designed to focus on the front brightness improvement effect using reflection. It is preferable.

Light transmissive part The light transmissive part can be formed by curing a composition for forming a light transmissive part. The composition for forming a light transmission part comprises a photocurable prepolymer polymerized using a bismuth compound as a catalyst, and an acylphosphine oxide photopolymerization initiator. The composition for forming a light transmissive part may further contain a photocurable monomer, and the light curable part forming composition can be cured by polymerizing a photocurable prepolymer and a photocurable monomer. In the polymerization of the photocurable prepolymer and the photocurable monomer, the following bismuth compound can be used as a catalyst as in the polymerization reaction of the photocurable prepolymer.

  In the present invention, an acyl phosphine oxide photopolymerization initiator is used as the photopolymerization initiator from the viewpoint of the size of the molecular structure and the small amount of movement within the film in the light transmission part. As the acylphosphine oxide photopolymerization initiator, it is preferable to use monoacylphosphine oxide and / or bisacylphosphine oxide from the viewpoint of compatibility with a photocurable prepolymer or a photocurable monomer. Monoacylphosphine oxide and bisacylphosphine oxide may be used alone or in combination. When monoacylphosphine oxide and bisacylphosphine oxide are used in combination, the photosensitivity can be adjusted by changing the blending ratio.

  Monoacylphosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethyl Examples include benzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, and pivaloylphenylphosphinic acid isopropyl ester. These may be used alone or in combination of two or more. In the present invention, commercially available products can also be used, for example, Lucian TPO (manufactured by BASF Corporation) can be suitably used.

  Examples of bisacylphosphine oxide include bis- (2,6-dichlorobenzoyl) phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, and bis- (2,6 -Dichlorobenzoyl) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis- (2,6-dimethoxybenzoyl) phenylphosphine oxide, bis- (2 , 6-Dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,5-dimethylphenylphosphine oxide, bis- (2,4,6-trimethyl) Benzoyl) phenylphosphine Kisaido, and (2,5,6-trimethylbenzoyl) -2,4,4-trimethylpentyl phosphine oxide. These may be used alone or in combination of two or more. In this invention, a commercial item can also be used, for example, Irgacure 819 (made by BASF Corporation) can be used conveniently.

  The photocurable prepolymer is preferably a urethane acrylate oligomer from the viewpoint of adjusting the refractive index and hardness of the light transmitting portion. The urethane acrylate oligomer is preferably obtained by polymerizing a polyisocyanate compound and a polyol compound using a bismuth compound as a catalyst. Furthermore, you may superpose | polymerize by adding the following photocurable monomer.

  A conventionally known polyisocyanate compound can be used as the polyisocyanate compound, and it is not particularly limited. For example, tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylxylylene diisocyanate , Isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, phenylene diisocyanate, lysine diisocyanate, lysine triisocyanate, naphthalene diisocyanate, and the like, and trimers of these polyisocyanates or a large amount of 4 or more Combination , Biuret type polyisocyanate, and water-dispersible polyisocyanate like. These may be used alone or in combination of two or more. In particular, isophorone diisocyanate or xylylene diisocyanate may be used in combination.

  A conventionally well-known polyol type compound can be used for a polyol type compound, and it is not specifically limited. For example, as the polyol compound, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, polybutylene glycol, 1,6-hexanediol, neopentyl Polyglycol, cyclohexanedimethanol, hydrogenated bisphenol A, polycaprolactone, trimethylolethane, trimethylolpropane, polytrimethylolpropane, pentaerythritol, polypentaerythritol, sorbitol, mannitol, glycerin, polyglycerin, polytetramethylene glycol, etc. Polyhydric alcohol, polyethylene oxide, polypropylene oxide , A polyether polyol having at least one structure of block or random copolymerization of ethylene oxide / propylene oxide, the polyhydric alcohol or polyether polyol and maleic anhydride, maleic acid, fumaric acid, itaconic anhydride, itaconic acid, Polyester polyols that are condensates with polybasic acids such as adipic acid and isophthalic acid, caprolactone-modified polyols such as caprolactone-modified polytetramethylene polyol, polyolefin polyols, polybutadiene polyols such as hydrogenated polybutadiene polyol, polycarbonate polyols, etc. Can be mentioned. Further, 2,2-bis (hydroxymethyl) butyric acid, tartaric acid, 2,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxy Carboxyl groups such as ethyl) propionic acid, 2,2-bis (hydroxypropyl) propionic acid, dihydroxymethylacetic acid, bis (4-hydroxyphenyl) acetic acid, 4,4-bis (4-hydroxyphenyl) pentanoic acid and homogentisic acid Also included are polyols containing sulfonic acid groups or sulfonate groups such as sodium 1,4-butanediol sulfonate. These may be used alone or in combination of two or more.

  The photocurable monomer is preferably a hydroxy group-containing acrylate compound from the viewpoint of reactivity with a photocurable prepolymer, particularly a urethane acrylate oligomer. As the hydroxy group-containing acrylate compound, a conventionally known hydroxy group-containing acrylate compound can be used and is not particularly limited. For example, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acryloyl phosphate, 2-acryloyloxyethyl-2-hydroxypropyl phthalate, glycerin diacrylate, Examples include 2-hydroxy-3-acryloyloxypropyl acrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, caprolactone-modified 2-hydroxyethyl acrylate, cyclohexane dimethanol monoacrylate, and phenoxyethyl acrylate. These may be used alone or in combination of two or more.

  The bismuth compound is preferably bismuth organic carboxylate from the viewpoint of good reaction efficiency as a catalyst, few by-products, and low environmental toxicity. Bismuth triacetate, bismuth tripropionate, bismuth triheptanoate, bismuth trioctanoate, bismuth tri (2-ethylhexanoate), bismuth tri (neodecanoate), bismuth trivertate, Examples thereof include bismuth trilaurate, bismuth trioleate, and bismuth tristearate. Among these, bismuth tri (2-ethylhexanoate) and bismuth tri (neodecanenoate) are preferable. These bismuth compounds can be synthesized by a conventionally known method. For example, it can be obtained by reacting bismuth oxide and the corresponding carboxylic acid in the presence or absence of a solvent.

  In addition, although this invention is not restrained by any theory, it is guessed as the following about the mechanism of the foreign material generation | occurrence | production in the light transmissive part by light irradiation. However, it goes without saying that the present invention should not be limited by the following description. When forming a light transmission part using the composition for forming a light transmission part, in the light transmission part, a small amount of bismuth compound used for the polymerization of the photocurable prepolymer, a photopolymerization initiator and / or photopolymerization. Initiator-derived residues (decomposed products) are present. The present inventors have found that when an alkylphenone-based photopolymerization initiator is used as a photopolymerization initiator, black foreign matters (black spots, black aggregates) are generated in the light transmission portion by light irradiation. When this black foreign material was analyzed by energy dispersive X-ray analysis (EDX), it was found to be derived from bismuth. On the other hand, when an acyl phosphine oxide photopolymerization initiator is used as a photopolymerization initiator, a surprising result has been found that no black foreign matter is generated in the light transmission portion even when light irradiation is performed. Therefore, when light (ultraviolet light) is irradiated to the light transmission part, the bismuth compound reacts with the alkylphenone photopolymerization initiator and / or the residue derived from the photopolymerization initiator to generate black foreign matters derived from bismuth. However, it is thought that when an acylphosphine oxide photopolymerization initiator is used, it does not react with the bismuth compound. This is due to the large molecular structure of acylphosphine oxide photopolymerization initiator and acylphosphine oxide photopolymerization initiator-derived residue (decomposition product), which limits the movement in the light transmission part and causes reaction with bismuth compounds. Is presumed to be suppressed. Therefore, in the present invention, a light transmission part is formed using an acyl phosphine oxide photopolymerization initiator instead of an alkylphenone photopolymerization initiator as a photopolymerization initiator, so that a light transmission part by light irradiation is formed in the light transmission part. The generation of foreign matter was suppressed.

Light Absorbing Part The light absorbing part can be formed by curing the light absorbing part forming composition. The composition for forming a light absorbing portion may include an ionizing radiation curable resin composition and light absorbing particles. As the ionizing radiation curable resin composition, an ionizing radiation curable resin composition used for a conventionally known visibility improving sheet, viewing angle improving sheet or the like can be used. For example, those having an acrylate functional group can be preferably used. For example, relatively low molecular weight polyester resin, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin, polybutadiene resin, polythiol polyene resin, oligomer such as acrylate of polyfunctional compound such as polyhydric alcohol Or a prepolymer can be mentioned. Although depending on the material constituting the light transmission portion of the visibility improving sheet, it is preferable to select a resin having a refractive index smaller than that of the material constituting the light transmission portion among these resins.

  In addition, a reactive diluent may be added to the resin composition. Examples of such a reactive diluent include monofunctional compounds such as ethyl acrylate, ethyl hexyl acrylate, styrene, methyl styrene, and N-vinyl pyrrolidone. Monomers as well as polyfunctional monomers may be used. For example, limethylolpropane triacrylate, hexanediol acrylate, tripropylene glycol diacrylate, diethylene glycol diacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, etc. Can be mentioned. These may be used alone or in combination of two or more.

  In order to make the ionizing radiation curable resin composition into an ultraviolet curable resin composition, acetophenones, benzophenones, Michler benzoylbenzoate, α-amyloxime ester, tetramethylchuram monomonoate as a photopolymerization initiator in the composition are used. A mixture of sulfides, thioxanthones, n-butylamine, triethylamine, poly-n-butylphosphine, or the like as a photosensitizer can be used. In particular, it is preferable to mix urethane acrylate as an oligomer and dipentaerythritol hexa (meth) acrylate as a monomer.

  As the light absorbing particles, particles that can selectively absorb a specific wavelength in accordance with the characteristics of the image light are preferably used. Examples of the light-absorbing particles include resin beads and glass beads kneaded or coated with a metal salt such as carbon black, graphite, fibrous carbon, black iron oxide, a dye, and a pigment. Can be used. From the viewpoint of easy kneading of the colorant, it is preferable to use resin beads.

  As the resin beads, melamine beads, acrylic beads, acrylic-styrene beads, polycarbonate beads, polyethylene beads, polystyrene beads, polyvinyl chloride beads and the like can be suitably used. Further, urethane cross-linked fine particles and silicon-based beads can also be suitably used. These resin beads are preferably those having a refractive index difference of about 0.1 of the ionizing radiation curable resin composition described above. Also, as the resin before kneading the colorant, a transparent resin can be used, but it is preferable to use a resin colored with a pigment or a dye, and a specific wavelength is selectively selected according to the characteristics of the image light. However, resin beads colored in black are preferably used.

  Among the above-mentioned materials, carbon black can be preferably used as the colorant. The amount of carbon black kneaded into the resin beads is about 0.1 to 0.7 parts by mass, preferably 0.15 to 0.5 parts by mass, more preferably 1 part by mass of the resin beads. Is 0.2 to 0.35 parts by mass. When the amount of kneading of carbon black is more than 0.7 parts by mass, the resin beads may be easily broken. On the other hand, when the amount is less than 0.1 parts by mass, light absorbing particles having desired blackness can be obtained. There may not be. Carbon black having an average particle diameter of 10 to 500 nm can be suitably used. For example, furnace black, acetylene black, channel black, thermal black, carbon nanotube, carbon fiber and the like can be used. Commercially available products can also be used. For example, HCF series, MCF series, RCF series, LFF series (above, manufactured by Mitsubishi Chemical Corporation), Vulcan series (manufactured by Cabot Corporation), Ketjen series (Lion Corporation) Can be suitably used. Here, the average particle diameter means an arithmetic average diameter obtained by observing carbon black particles with an electron microscope.

  The addition amount of the light absorbing particles is preferably in the range of 15 to 35% with respect to the total mass of the light absorbing portion forming composition. When the amount of the light absorbing particles added is in the above range, a louver sheet with better contrast can be realized.

  In order to improve the dispersibility of the light absorbing particles in the ionizing radiation curable resin composition, the light absorbing particles can be surface-treated. Examples of the surface treatment include hydrophilic treatment with a conventionally known silica coating and surface modification with plasma or the like.

Method for Producing Louver Sheet The method for producing a louver sheet according to the present invention comprises a step of forming a light transmission part and a step of forming a light absorption part. Hereinafter, each process of the manufacturing method of the louver sheet | seat by this invention is demonstrated in detail.

Step of forming light transmissive portion The step of forming the light transmissive portion comprises curing a light transmissive portion forming composition comprising a photocurable prepolymer polymerized using a bismuth compound as a catalyst, and a photopolymerization initiator, This is a step of forming a light transmission part having a plurality of grooves arranged on the surface.

  The light transmitting part can be formed by a conventionally known method, and the forming method is not particularly limited as long as the light transmitting part forming composition is cured. For example, the light transmission part can be formed by a so-called UV method in which the light transmission part forming composition described above is supplied into a mold and irradiated with light (ultraviolet rays) to be cured. In the present invention, a UV method excellent in mass productivity can be suitably used. According to the UV method, the light transmission part can be continuously produced using a mold roll.

  Specifically, for example, as shown in FIG. 2, the base material 1 is fed between a mold roll 10 having a groove corresponding to the shape of the light transmission part 2 and a nip roll 11 at a predetermined pitch. The arrow in FIG. 2 represents the direction in which the base material 1 is fed. In accordance with the feeding of the base material 1, the droplets of the light transmission part forming composition 13 are continuously supplied from the supply part 12 between the mold roll 10 and the base material 1. When supplying the light transmissive part forming composition 13 from the supply unit 12 onto the base material 1, the composition reservoir 14 in which the light transmissive part forming composition 13 is accumulated between the mold roll 10 and the base material 1. To be formed. By forming the composition reservoir 14, the light transmitting portion forming composition 13 spreads in the width direction of the substrate 1.

  The composition 13 for forming a light transmitting portion supplied between the mold roll 10 and the base material 1 as described above is formed by the pressing force between the mold roll 10 and the nip roll 11. It is filled between the molds 10. Thereafter, the ultraviolet ray irradiation device 15 irradiates the light transmission part forming composition 13 with ultraviolet rays to cure the light transmission part forming composition 13 to form the light transmission part 2. After forming the light transmission part 2, the light transmission part 2 is peeled off from the mold roll 10 through the peeling roll 16.

  As described above, as shown in FIG. 3, the light transmission part 2 in which a plurality of grooves 2 a are arranged in parallel in the cross section in the layer thickness direction can be formed on the substrate 1. The groove 2a shown in FIG. 3 has a substantially trapezoidal shape that tapers toward the substrate 1 side. The groove 2a is not limited to a substantially trapezoidal shape, and may be formed in, for example, a substantially V shape or a substantially rectangular shape. The groove 2 a extends along the longitudinal direction of the substrate 1.

  The base material 1 is a layer serving as a base for forming the light transmission part 2. As the substrate 1, a transparent resin film, a transparent resin plate, a transparent resin sheet, or transparent glass can be used. Transparent resin films include triacetate cellulose (TAC) film, polyester film such as polyethylene terephthalate (PET), diacetyl cellulose film, acetate butyrate cellulose film, polyethersulfone film, polyacrylic resin film, polyurethane resin film Polyester film, polycarbonate film, polysulfone film, polyether film, polymethylpentene film, polyether ketone film, (meth) acrylonitrile film, etc. can be suitably used. Among these, polyester films are preferably used. . Examples of the polyester film include polyethylene terephthalate, polybutylene terephthalate, polynaphthalene terephthalate, and polytrimethylene terephthalate.

Formation Step of Light Absorbing Part In the forming step of the light absorbing part, the light absorbing part forming composition is supplied into the groove of the light transmitting part, and the light absorbing part forming composition is cured to form the light absorbing part. It is a process.

  As a method for supplying the composition for forming a light absorbing portion into the groove of the light transmitting portion, a conventionally known method can be used, and the supplying method is not particularly limited. For example, examples of the supply device for the composition for forming a light absorbing portion include a die coater, a bar coater, a roll coater, and a knife coater.

  A conventionally known method can be used as a curing method of the composition for forming a light absorbing portion supplied into the groove of the light transmitting portion, and the curing method is not particularly limited. For example, as a curing method, it can be cured by irradiation with an electron beam or ultraviolet rays. In the case of electron beam curing, 50 to 1000 keV emitted from various electron beam accelerators such as cockroft Walton type, bandegraph type, resonant transformation type, insulated core transformer type, linear type, dynamitron type, and high frequency type. Preferably, an electron beam having an energy of 100 to 300 keV is used. In the case of ultraviolet curing, ultraviolet rays emitted from a light source such as an ultra high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, and a metal halide lamp can be used.

Optical sheet The optical sheet according to the present invention is selected from the group consisting of a louver sheet according to the present invention and an antiglare layer, an antireflection layer, an antistatic layer, a hard coat layer, and an antifouling layer on the image light exit side of the louver sheet. And at least one functional layer. In particular, it is preferable to provide an antireflection layer on the image light emitting side of the louver sheet. The order of stacking and the number of stacks of these functional layers can be appropriately determined according to the application. Each of these functional layers can be formed by a conventionally known method. In addition, the optical sheet may further include an adhesive layer in order to be disposed on the display unit of the display device.

  The optical sheet according to the present invention preferably does not include an ultraviolet absorbing layer on the image light exit side of the louver sheet. This is because the optical sheet according to the present invention has sufficient light resistance even if the ultraviolet absorbing layer is removed, and the cost can be reduced and the manufacturing process can be simplified by removing the ultraviolet absorbing layer. .

  For example, the optical sheet 7 shown in FIG. 4 includes an antireflection layer 5, a louver sheet 3 including a base material 1, a light transmission part 2, and a light absorption part 4, and an adhesive layer 6 from the image light emission side. Prepare.

Image Display Device An image display device according to the present invention includes the optical sheet according to the present invention and a display unit. Examples of the display unit of the image display device include a plasma display, a liquid crystal display, an organic EL display, a field emission display (FED), a surface conduction electron-emitting device display (SED), and a projection television.

  For example, the image display device 9 shown in FIG. 5 includes an optical sheet 7 and a display unit 8, and the optical sheet 7 includes the antireflection layer 5 and the base material 1 from the image light emission side. , A louver sheet 3 comprising a light transmission part 2 and a light absorption part 4, and an adhesive layer 6.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not construed as being limited to the contents of the following examples.

Example 1
Preparation of composition for forming light transmitting part 41 parts by mass of bisphenol A-ethylene oxide 2 mol adduct, 14.0 parts by mass of isophorone diisocyanate, and bismuth tri (2-ethylhexanoate) (2-ethylhexanoic acid) as urethanization catalyst 50% solution)) Add 0.02 parts by mass and react at 80 ° C. for 5 hours, then add 5 parts by mass of 2-hydroxyethyl acrylate and react at 80 ° C. for 5 hours to obtain a urethane acrylate oligomer. And used as a photocurable prepolymer. This urethane acrylate oligomer 32, 0 parts by mass, 10.0 parts by mass of phenoxyethyl acrylate (molecular weight 192) as a photocurable monomer, and 30.0 masses of diacrylate (molecular weight 512) of EO4 mol adduct of bisphenol A And 0.03 parts by mass of a tetradecanol-ethylene oxide 10-mole adduct as a mold release agent (monoester / diester = molar ratio 1/1), and a tearylamine ethylene oxide 15-mole adduct 02 parts by mass, as a photopolymerization initiator, 3 parts by mass of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (trade name: Lucillin TPO, manufactured by BASF Corporation) are mixed and homogenized to form a light transmission part composition I got a thing.

Preparation of composition for forming light absorption part 20.0 parts by mass of epoxy acrylate oligomer as photocurable prepolymer, 20.0 parts by mass of 2-phenoxyethyl acrylate as reactive diluent monomer, α-acryloyl-ω- 20.0 parts by mass of phenoxypoly (oxyethylene), and 13.0 parts by mass of 2- {2- [2- (acryloyloxy) (methyl) ethoxy] (methyl) ethoxy} (methyl) ethyl acrylate, and light absorption As particles, 20.0 parts by mass of acrylic crosslinked fine particles (manufactured by Ganz Kasei Co., Ltd.) containing 25% of carbon black having an average particle size of 4.0 μm and 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184 (manufactured by BASF Corp.) and 7 parts by mass for mixing and homogenizing for light absorption part formation It was obtained Narubutsu.

Production of louver sheet The light transmissive part forming composition prepared above is supplied onto a polyethylene terephthalate substrate (Toyobo Co., Ltd., A4300, 100 μm), the light transmissive part forming composition is cured, and a plurality of compositions are formed on the surface. The light transmission part in which the groove | channels were arranged in parallel was formed.

  Next, while moving the light transmissive part for each substrate, the light transmissive part is uniformly supplied in the width direction of the light transmissive part from the die head of the die coater. After that, the excess light-absorbing part forming composition on the surface of the light transmission part was scraped off using a scraping member.

  After the light-absorbing part forming composition is filled in the groove of the light-transmitting part, the light-absorbing part-forming composition is cured by irradiating the light-absorbing part-forming composition with ultraviolet rays. The louver sheet of Example 1 provided with the light transmission part and the light absorption part was produced.

Reference example 1
Preparation of composition for forming light transmitting part 41 parts by mass of bisphenol A-ethylene oxide 2 mol adduct, 14.0 parts by mass of isophorone diisocyanate, and bismuth tri (2-ethylhexanoate) (2-ethylhexanoic acid) as urethanization catalyst 50% solution)) Add 0.02 parts by mass and react at 80 ° C. for 5 hours, then add 5 parts by mass of 2-hydroxyethyl acrylate and react at 80 ° C. for 5 hours to obtain a urethane acrylate oligomer. And used as a photocurable prepolymer. This urethane acrylate oligomer 32, 0 parts by mass, 10.0 parts by mass of phenoxyethyl acrylate (molecular weight 192) as a photocurable monomer, and 30.0 masses of diacrylate (molecular weight 512) of EO4 mol adduct of bisphenol A And 0.03 parts by mass of a tetradecanol-ethylene oxide 10-mole adduct as a mold release agent (monoester / diester = molar ratio 1/1), and a tearylamine ethylene oxide 15-mole adduct 02 parts by mass, 3 parts by mass of bis- (2,4,6-trimethylbenzoyl) phenylphosphine oxide (trade name: Irgacure 819, manufactured by BASF Corporation) as a photopolymerization initiator are mixed, homogenized and light-transmitted A composition for forming a part was obtained.

Production of Louver Sheet A louver sheet of Reference Example 1 was produced in the same manner as in Example 1 except that the light transmitting part forming composition prepared above was used.

Comparative Example 1
Preparation of composition for forming light transmitting part 41 parts by mass of bisphenol A-ethylene oxide 2 mol adduct, 14.0 parts by mass of isophorone diisocyanate, and bismuth tri (2-ethylhexanoate) (2-ethylhexanoic acid) as urethanization catalyst 50% solution)) Add 0.02 parts by mass and react at 80 ° C. for 5 hours, then add 5 parts by mass of 2-hydroxyethyl acrylate and react at 80 ° C. for 5 hours to obtain a urethane acrylate oligomer. And used as a photocurable prepolymer. This urethane acrylate oligomer 32, 0 parts by mass, 10.0 parts by mass of phenoxyethyl acrylate (molecular weight 192) as a photocurable monomer, and 30.0 masses of diacrylate (molecular weight 512) of EO4 mol adduct of bisphenol A And 0.03 parts by mass of a tetradecanol-ethylene oxide 10-mole adduct as a mold release agent (monoester / diester = molar ratio 1/1), and a tearylamine ethylene oxide 15-mole adduct 02 parts by mass, 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufactured by BASF Corporation) as a photopolymerization initiator were mixed and homogenized to obtain a composition for forming a light transmission part.

Production of Louver Sheet A louver sheet of Comparative Example 1 was produced in the same manner as in Example 1 except that the light transmitting part forming composition prepared above was used.

Light Resistance Test The louver sheets of Examples and Comparative Examples produced as described above were irradiated with ultraviolet rays under the following conditions, and it was observed with a microscope whether or not foreign matter was generated in the light transmission part.
Test conditions Light source: Xenon arc lamp (manufactured by Suga Test Instruments Co., Ltd., trade name: SX75)
Irradiance: 60 W / m ² (300 to 400 nm)
Irradiation time: 120 hours Irradiation temperature: 63 degrees Humidity: 50%

The evaluation criteria of the above light resistance test are as follows. The evaluation results are shown in Table 1. In addition, FIG. 6 (Example 1) and FIG. 7 (Comparative Example 1) show micrographs after the light resistance test of the louver sheet.
-Evaluation criteria ( circle): The foreign material did not generate | occur | produce in the light transmissive part.
X: Black foreign matter was generated in the light transmission part.

  From the above results, by forming a light transmission part using an acylphosphine oxide photopolymerization initiator instead of an alkylphenone photopolymerization initiator as a photopolymerization initiator, foreign matter in the light transmission part due to light irradiation Occurrence could be suppressed.

DESCRIPTION OF SYMBOLS 1 Base material 2 Light transmission part 2a Groove 3 Louver sheet 4 Light absorption part 5 Antireflection layer 6 Adhesive layer 7 Optical sheet 8 Display part 9 Image display apparatus 10 Mold roll 11 Nip roll 12 Supply part 13 Composition for light transmission part formation 14 Composition reservoir 15 UV irradiation device 16 Peeling roll

Claims (8)

A louver sheet,
An optical sheet comprising at least one functional layer selected from the group consisting of an antiglare layer, an antireflection layer, an antistatic layer, a hard coat layer, and an antifouling layer on the image light emitting side of the louver sheet. ,
The louver sheet comprises a light transmission part having a plurality of grooves arranged in parallel on the surface, and a light absorption part formed in the groove of the light transmission part,
That the light transmitting section includes a bismuth compound, a photocurable prepolymer, Ri name and a mono acyl phosphine oxide, a light transmitting portion forming composition containing no bisacylphosphine oxide is formed by curing An optical sheet, characterized in that A louver sheet,
At least one functional layer selected from the group consisting of an antiglare layer, an antireflection layer, an antistatic layer, a hard coat layer, and an antifouling layer provided on the image light emitting side of the louver sheet;
An adhesive sheet provided on the side opposite to the side on which the functional layer of the louver sheet is provided, and an optical sheet comprising:
The louver sheet comprises a light transmission part having a plurality of grooves arranged in parallel on the surface, and a light absorption part formed in the groove of the light transmission part,
That the light transmitting section includes a bismuth compound, a photocurable prepolymer, Ri name and a mono acyl phosphine oxide, a light transmitting portion forming composition containing no bisacylphosphine oxide is formed by curing An optical sheet, characterized in that   The monoacylphosphine oxide is 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethyl. The optical sheet according to claim 1 or 2, wherein the optical sheet is at least one selected from the group consisting of benzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, and pivaloylphenylphosphinic acid isopropyl ester. .   The optical sheet according to claim 1, wherein the photocurable prepolymer is a urethane acrylate oligomer.   The optical sheet according to claim 4, wherein the urethane acrylate oligomer is obtained by polymerizing a polyisocyanate compound and a polyol compound using the bismuth compound as a catalyst.   The optical sheet according to any one of claims 1 to 5, wherein the bismuth compound is bismuth organic carboxylate.   The organic carboxylic acid bismuth is bismuth triacetate, bismuth tripropionate, bismuth triheptanoate, bismuth trioctanoate, bismuth tri (2-ethylhexanoate), bismuth tri (neodecanoate), bismuth trivertate, The optical sheet according to claim 6, which is at least one selected from the group consisting of bismuth trilaurate, bismuth trioleate, and bismuth tristearate.   The image display apparatus provided with the optical sheet as described in any one of Claims 1-7, and a display part.