阅读说明：本技术 光散射体、光散射体形成用组合物、片状层叠体、投影屏幕、光扩散片及内藏光增强器的照明装置 (Light scattering body, composition for forming light scattering body, sheet-like laminate, projection screen, light diffusion sheet, and illumination device incorporating light intensifier ) 是由 北本隆志 织田扩 艾合买提·肖开提 渡边浩之 斋藤一 吉田武司 于 2019-02-22 设计创作，主要内容包括：本发明的光散射体(5)含有：包含树脂的树脂介质(3)、以及分散于树脂介质(3)中的中空粒子(1)及光散射粒子(2)。树脂介质(3)的折射率比光散射粒子(2)的折射率低。(The light scattering body (5) of the present invention comprises: a resin medium (3) containing a resin, and hollow particles (1) and light-scattering particles (2) dispersed in the resin medium (3). The refractive index of the resin medium (3) is lower than the refractive index of the light scattering particles (2).)

1. A light scattering body is formed by dispersing hollow particles and light scattering particles in a resin medium having a refractive index lower than that of the light scattering particles.

2. The light scatterer of claim 1, wherein said light scattering particles are diamond.

3. The light scatterer according to claim 1 or 2, wherein the hollow particle has a pore diameter of 0.78 μm or more and 300 μm or less.

4. A composition for forming a light scattering body, comprising a hollow particle precursor, a light scattering particle, and a resin, wherein the refractive index of the light scattering particle is higher than the refractive index of the resin.

5. A sheet-like laminate comprising a substrate and a light-scattering layer comprising the light-scattering body according to any one of claims 1 to 3 provided on the substrate.

6. A projection screen comprising the light scattering body according to any one of claims 1 to 3 or the sheet laminate according to claim 5.

7. A light diffusing sheet comprising a light scattering layer comprising the light scatterer according to any one of claims 1 to 3.

8. An illumination device with a built-in light booster, comprising: a light intensifier comprising the light scattering body according to any one of claims 1 to 3 or the sheet laminate according to claim 5; and a light source.

Technical Field

The present invention relates to a light scattering body, a composition for forming a light scattering body, a sheet laminate, a projection screen, a light diffusing sheet, and an illumination device incorporating a light intensifier.

Background

Reflective screens, which project images projected by a projector onto a screen and view the images from the projector side, and transmissive screens, which view the images from the back, are used in various fields such as home theaters, digital signage, and advertising media for events.

As such a screen, for example, a screen including a layer in which bubbles are contained in a base material to reflect incident light is known.

Patent document 1 discloses a technique of using a polyester resin foam sheet containing oriented elliptical cells having an average cell diameter of 12 μm or less as a reflection sheet for image projection.

Patent document 2 discloses a diffuser plate for a projector transmission screen, which is characterized by comprising a resin composition containing (a) a cycloolefin-based resin: 90 to 99.9 parts by weight, and (B) organic crosslinked particles: 10 to 0.1 parts by weight (wherein the total of (A) and (B) is 100 parts by weight), total light transmittance is 0% or more, and refractive index n of the cycloolefin resin (A)_ARefraction by the organic crosslinked particles (B)Rate n_BAbsolute value | n of the difference of_B-n_AThe | -is 0.04 or more, and the average particle diameter of the organic crosslinked particles (B) is 2.0 μm or more.

Patent document 3 discloses a screen technique in which an internal void is formed perpendicular to the fiber axis direction using 2-component polymer blend fibers that are not miscible.

Patent document 4 discloses a technique of using a light diffusion sheet containing a plurality of bubbles in a resin as a projection screen.

Patent document 5 discloses a technique of a translucent projection screen in which a film containing a thermoplastic resin having a total light transmittance of 30 to 80% and a total light reflectance of 20 to 70% can exhibit a function of viewing an image in both reflected light and transmitted light.

Patent document 6 discloses a screen technology in which through holes having an opening diameter of 0.1 to 8mm are drilled at an interval of 0.1 to 5mm, which is the shortest distance between the holes, in the thickness direction of a film layer containing a thermoplastic resin, so that the total light transmittance is 30 to 80% and the total light reflectance is 20 to 70%.

Disclosure of Invention

Problems to be solved by the invention

However, as a result of studies by the present inventors, it has been found that the screens of patent documents 1 to 6 have insufficient visibility because the sharpness and brightness of the projected image are insufficient.

The present invention has been made in view of the above-described technical problems, and an object of the present invention is to provide a light scattering body capable of projecting a clear and bright image, a composition for forming a light scattering body capable of forming the same, and a sheet laminate, a projection screen, a light diffusing sheet, and an illumination device incorporating a light intensifier, each using the light scattering body.

Means for solving the problems

The present inventors have made extensive studies to achieve the above object, and as a result, have completed the following inventions.

The invention provides a light scattering body, which is formed by dispersing hollow particles and light scattering particles in a resin medium with a lower refractive index than the light scattering particles.

The light scattering particles are preferably diamond.

The hollow particle preferably has a pore diameter of 0.78 to 300 μm.

The present invention also provides a composition for forming a light scattering body, which contains a hollow particle precursor, a light scattering particle, and a resin, and the refractive index of the light scattering particle is higher than the refractive index of the resin.

The sheet laminate of the present invention comprises a base material and a light scattering layer provided on the base material and containing the light scattering body.

The projection screen of the present invention includes the light scattering body or the sheet laminate.

The light diffusion sheet of the present invention includes a light diffusion layer including the light scattering body.

The lighting device with the built-in light intensifier of the invention comprises: a light intensifier including the light scattering body or the sheet laminate; and a light source.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a light scattering body capable of projecting a clear and bright image, a composition for forming a light scattering body capable of forming the same, and a sheet laminate, a projection screen, a light diffusing sheet, and an illumination device incorporating a light intensifier, each using the light scattering body, can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view illustrating a light scattering body according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view showing a sheet laminate according to an embodiment of the present invention.

Fig. 3 is a schematic cross-sectional view showing a sheet laminate according to an embodiment of the present invention.

Fig. 4 is a layout diagram of a light scattering measurement of the sheet laminate according to the embodiment of the present invention.

Fig. 5 is an angular distribution diagram of the light scattering intensity of the sheet laminate according to the embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view showing a composite light diffusion sheet according to an embodiment of the present invention.

Fig. 7 is a schematic cross-sectional view showing a lighting device incorporating a light booster according to an embodiment of the present invention.

Detailed Description

The following describes an embodiment of the present invention in detail. However, the present invention is not limited to the following embodiments.

[ light scatterer ]

The light scattering body of the present embodiment includes a resin medium, hollow particles dispersed in the resin medium, and light scattering particles dispersed in the resin medium. The refractive index of the resin medium is lower than that of the light scattering particles.

Fig. 1 is a schematic cross-sectional view showing a light scattering body according to the present embodiment. The light scattering body 5 shown in fig. 1 includes a resin medium 3, and hollow particles 1 and light scattering particles 2 dispersed in the resin medium 3.

First, the resin medium will be described. The resin medium contains at least a resin as a constituent component, and the resin functions as a matrix resin for fixing the hollow particles and the light scattering particles in the light scattering body, for example.

The resin medium may be formed of a resin composition containing a resin.

Examples of the resin include thermoplastic resins and thermosetting resins, and specifically, polycarbonate resins, polyurethane resins, polyacrylic resins, polystyrene resins, polyolefin resins, vinyl resins, polyester resins, polyether resins, fluorine resins, polysulfone resins, polyether ether ketone resins, polyamide resins, polyimide resins, melamine resins, phenol resins, epoxy resins, silicone resins, cellulose resins, silicone-modified acrylic resins, and the like. When these resins are used, the difference in refractive index between the light scattering particles and the resin tends to be easily obtained, and the visibility tends to be further excellent. The resin medium preferably contains a urethane resin, a polyacrylic resin, or a silicone-modified acrylic resin, and more preferably contains a silicone-modified acrylic resin, from the viewpoint of preventing aggregation of light scattering particles contained in the light scattering body. The resin medium may contain 1 kind of resin alone or 2 or more kinds of resins.

The resin composition may contain other components than the resin. Examples of the other components include: anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, preservatives, light stabilizers, ultraviolet absorbers, antioxidants, polymerization inhibitors, silicone defoamers, leveling agents, tackifiers, anti-settling agents, anti-dripping agents, flame retardants, fluorescent brighteners, viscosity stabilizers, pH adjusters, various additives for organic/inorganic pigments/dyes, addition aids, antistatic agents, matting agents, and the like. Among these, the respective surfactants are preferably contained from the viewpoint of preventing aggregation of light scattering particles and the like contained in the light scattering body. The surfactant is preferably an anionic surfactant or a nonionic surfactant; more preferably, anionic surfactants such as alkylbenzenesulfonates, polyoxyethylene alkylphenylether sulfate salts, styrenated phenol alkylene oxide adduct sulfate salts, alkylnaphthalenesulfonates, naphthalenesulfonic acid-formaldehyde condensate salts, and alkyldiphenylether disulfonates; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene sorbitan fatty acid partial esters (part エステル), polyoxyethylene glycerin fatty acid partial esters, polyoxyethylene glycol fatty acid esters, polyoxyethylene polyoxypropylene block polymers, and polyethylene glycol mono (styrylphenyl) ethers; further preferably a styrenated phenol alkylene oxide adduct sulfuric acid ester salt, an alkylnaphthalene sulfonate or a naphthalenesulfonic acid formaldehyde condensate salt; particularly preferred is a styrenated phenol alkylene oxide adduct sulfuric acid ester salt or a naphthalenesulfonic acid formaldehyde condensate salt.

The refractive index of the resin medium is preferably 1.28 or more and less than 1.80, more preferably 1.30 or more and 1.60 or less, and still more preferably 1.40 or more and 1.60 or less. The refractive index in this specification means a measurement at a wavelength of 589.3nm of a sodium lamp.

The content of the resin medium in the light scattering body is preferably 40 to 95% by mass, and more preferably 50 to 90% by mass, based on the total amount of the light scattering bodies, from the viewpoint of dispersibility of the particles.

The hollow particles have a hollow structure with a hollow hole surrounded by a thin layer.

As the hollow particles, hollow polymers having pores may be used as they are, or they may be formed by treating precursors which form hollow particles by a treatment such as heating. Examples of the precursor for forming the hollow particles by a treatment such as heating include heat-expandable microcapsules.

The hollow particle has a pore diameter of preferably 0.78 to 300. mu.m, more preferably 0.9 to 100. mu.m, and still more preferably 0.9 to 30 μm, from the viewpoint of visibility. The pore diameter can be determined by measuring the pore diameter (diameter) of each particle for any 50 or more hollow particles by scanning microscope measurement and arithmetically averaging the pore diameters. In the observation photograph (figure), when the shape of the hollow hole is not a true circle, the diameter of the maximum inscribed circle of the cross section of the hollow hole is measured.

Examples of the material of the thin layer of hollow particles include: inorganic substances such as silicon oxide, glass, titanium oxide, and aluminum oxide; organic materials such as phenol resins, epoxy resins, acrylic resins, styrene resins, and urea resins. Among these, from the viewpoint of visibility, organic resins such as acrylic resins, styrene resins, and urea resins are preferable, and acrylic resins or styrene resins are more preferable.

The hollow polymer is a capsule in which a gas such as air is sealed. Examples of the material of the hollow polymer include inorganic substances such as silica, glass, titanium oxide, and alumina; organic materials such as phenol resins, epoxy resins, acrylic resins, styrene resins, and urea resins.

The heat-expandable microcapsule is a structure in which a heat-expandable gas is enclosed inside a core, and the enclosed heat-expandable gas is expanded by heating, thereby forming hollow particles having a hollow structure. The gas inside the core may be a low boiling point hydrocarbon. Examples of the material constituting the thin layer of the thermally expandable microcapsule include: inorganic substances such as silicon oxide, glass, titanium oxide, and aluminum oxide; organic materials such as phenol resins, epoxy resins, acrylic resins, styrene resins, and urea resins.

The thickness of the thin layer of the hollow particles is preferably 1.0nm to 10 μm from the viewpoint of visibility and structural stability of the hollow particles. When the material of the thin layer is titanium oxide or aluminum oxide, the thickness of the thin layer is preferably 1.0nm to 1 μm. The measurement was performed by a scanning electron microscope, and the thin layer of each particle was measured for any 50 or more hollow particles, and the results were obtained by arithmetic mean. In the observation photograph (figure), when the thickness of the thin layer is not constant, the maximum value and the minimum value of the thin layer are measured and averaged.

The content of the hollow particles is preferably 3 to 50% by mass, more preferably 5 to 40% by mass, based on the total amount of the light scattering bodies, from the viewpoint of visibility.

The light scattering particles may have a refractive index higher than that of the resin medium. As components constituting the light scattering particles, for example: diamond; metal oxides such as zirconium oxide, titanium oxide, barium titanate, strontium titanate, aluminum oxide, zinc oxide, copper oxide, cesium oxide, chromium oxide, niobium oxide, cerium oxide, indium tin oxide, and tantalum oxide; metals such as aluminum, nickel, cobalt, iron, titanium, chromium, zinc, tungsten, mercury, platinum, molybdenum, and the like; and resins such as polycarbonate resins, polyurethane resins, polyacrylic resins, polystyrene resins, polyvinyl alcohol resins, polyolefin resins, polyvinyl olefin resins, cycloolefin resins, polyester resins, polyether resins, fluorine resins, polysulfone resins, polyether ether ketone resins, polyamide resins, polyimide resins, melamine resins, phenol resins, epoxy resins, silicone resins, cellulose resins, and silicone-modified acrylic resins.

Among these, the refractive index is preferably 1.8 or more, more preferably 2.0 or more, and still more preferably 2.2 or more. The upper limit of the refractive index is not particularly limited, and may be set to 4.0 or less, for example.

As the material having a refractive index of 1.8 or more, there can be mentioned: diamond; metal oxides such as zirconium oxide, titanium oxide, barium titanate, strontium titanate, zinc oxide, copper oxide, cesium oxide, chromium oxide, niobium oxide, cerium oxide, indium tin oxide, and tantalum oxide; nickel, cobalt, iron, titanium, chromium, zinc, tungsten, mercury, platinum, molybdenum, and the like. As the material having a refractive index of 2.0 or more, there can be mentioned: diamond; metal oxides such as zirconium oxide, titanium oxide, barium titanate, strontium titanate, zinc oxide, copper oxide, cesium oxide, chromium oxide, niobium oxide, cerium oxide, indium tin oxide, and tantalum oxide; cobalt, iron, titanium, chromium, zinc, tungsten, mercury, platinum, molybdenum and other metals. Among these, diamond, metal oxide, and metal are preferable from the viewpoint of effectively scattering light, and diamond is more preferable from the viewpoint of visibility and a high viewing angle. The light-scattering particles may contain these components alone or 2 or more. Further, as the light scattering particles, 1 kind of particles containing the same constituent component may be used, or plural kinds of particles having different constituent components may be used.

There are many kinds of diamond depending on the production method and the purification method, and any of them can be used. Examples thereof include: natural diamond; synthetic diamonds such as high-pressure synthetic diamonds, explosion synthetic diamonds, vapor-phase grown diamonds, and the like.

In addition, the diamond is divided into 2 kinds of single crystal diamond and polycrystalline diamond according to the morphological structure of the crystal, and the single crystal diamond and the polycrystalline diamond can be used alone or mixed.

The median particle diameter of the light-scattering particles is preferably 40nm to 10 μm, and more preferably 70nm to 1.0 μm, from the viewpoint of visibility. The light scattering particles may be 1 type or 2 or more types having different median particle diameters. In the present specification, the median diameter refers to a 50% median diameter on a volume basis of the particles, and is measured by using a particle size distribution meter of a laser diffraction scattering method (for example, LA-960, manufactured by horiba, Ltd.).

The shape of the light scattering particles is not particularly limited, and may be, for example: spherical, roughly spherical, spheroid, broken, amorphous, cubic, rectangular, plate, pyramid, cone, phosphor flake, and the like. From the viewpoint of visibility, a spherical shape, a substantially spherical shape, or a shape of a rotating ellipsoid is preferable.

The content of the light scattering particles is preferably 1 to 25% by mass, more preferably 2 to 20% by mass, based on the total amount of the light scattering particles, from the viewpoint of visibility.

The mass ratio of the light-scattering particles to the hollow particles (mass of light-scattering particles/mass of hollow particles) is preferably 0.05 to 0.80, more preferably 0.15 to 0.60, from the viewpoint of visibility.

The refractive index of the light scattering particles is preferably greater than the refractive index of the resin medium by 0.2 or more, more preferably greater than 0.4 or more, and still more preferably greater than 0.6 or more. The upper limit of the difference in refractive index between the light scattering particles and the resin medium is not particularly limited, and may be, for example, 2 or less.

The light scattering body of the present embodiment is preferably sheet-shaped. The thickness is not particularly limited, but is preferably 0.1 to 500 μm, more preferably 0.5 to 80 μm, from the viewpoint of better visibility and better economy. The thickness of the light scatterer in the present specification was measured by using a micrometer (product name: MDH-25M, manufactured by ミツトヨ Co.).

The light scattering body of the present embodiment can be manufactured, for example, by a method including the steps of: a step of applying the following composition for forming a light scattering body on a release substrate; a step of drying or curing the coating film; and a step of peeling the dried product or the cured product from the release substrate.

[ composition for Forming light Scattering ]

The composition for forming a light-scattering body of the present embodiment includes a hollow particle precursor, a light-scattering particle, and a resin.

The composition for forming a light scattering body according to the present embodiment may contain a resin composition.

The same resin composition as that used to form the resin medium in the light scattering body of the present embodiment can be used as the resin composition. The resin composition may contain a polymerizable monomer (for example, a monomer mixture) capable of forming the resin, and a polymerization initiator if necessary, in place of or in combination with the resin. When the resin contained in the resin composition is the above-mentioned resin or a raw material thereof, the dispersibility of the particles is excellent, and thus a light scattering body excellent in visibility is easily obtained. In the present embodiment, a commercially available product as a solution (resin solution) obtained by diluting or dispersing the resin with a solvent may be used.

Examples of the polymerizable monomer include: (meth) acrylic acid; (meth) acrylate compounds such as ethyl (meth) acrylate, methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobutyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; olefin compounds such as ethylene, propylene, butene, hexene, butadiene, and isoprene; halogenated olefin compounds such as vinyl chloride and dichloroethylene; cycloalkene compounds such as cyclohexene; styrene; epoxy compounds such as ethylene oxide and propylene oxide; and silane compounds such as γ -methacryloxypropylalkoxysilane. The polymerizable monomer may be the above-mentioned resin having a polymerizable functional group.

As the polymerization initiator, there can be mentioned: thermal radical polymerization initiators such as azo compounds and peroxides; thermal cationic polymerization initiators such as benzoic acid sulfonate compounds and alkyl sulfonium salts; and photopolymerization initiators such as benzoin compounds and acetophenone compounds.

The content of the resin composition in terms of solid content is preferably 22 to 98.5% by mass, and more preferably 30 to 96% by mass, based on the total amount of the composition for forming light scatterers, from the viewpoint of dispersibility.

As the hollow particle precursor in the composition for forming a light scattering body, a hollow polymer having a hollow hole or the like can be used, or a precursor which forms a hollow particle by a treatment such as heating can be used. As the hollow particle precursor, the same substances as those described in the hollow particles of the present embodiment can be used.

The total content of the hollow particle precursors in the composition for forming a light scatterer is preferably 1.1 to 69.0% by mass, more preferably 2.9 to 56.0% by mass, based on the total amount of the composition for forming a light scatterer, from the viewpoint of dispersibility.

As the light-scattering particles in the light-scattering-body-forming composition, the same light-scattering particles as those of the present embodiment described above can be used.

The total content of the light-scattering particles in the light-scattering-body-forming composition is preferably 0.4 to 9.0% by mass, and more preferably 0.7 to 7.5% by mass, based on the total amount of the light-scattering-body-forming composition, from the viewpoint of dispersibility.

The composition for forming a light scattering body may optionally contain inorganic particles other than light scattering particles, organic particles other than light scattering particles, metal oxide particles other than light scattering particles, a solvent, a polymerization initiator, an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, a preservative, a light stabilizer, an ultraviolet absorber, an antioxidant, a polymerization inhibitor, a silicone defoamer, a leveling agent, a thickener, an anti-settling agent, an anti-dripping agent, a flame retardant, a fluorescent brightener, a viscosity stabilizer, a pH adjuster, various additives of organic/inorganic pigments/dyes, an addition aid, an antistatic agent, a matting agent, and the like. Among these, from the viewpoint of preventing aggregation of light scattering particles and the like contained in the light scattering body, it is preferable to include the respective surfactants. The surfactant is preferably an anionic surfactant or a nonionic surfactant; more preferably, anionic surfactants such as alkylbenzenesulfonates, polyoxyethylene alkylphenylether sulfate salts, styrenated phenol alkylene oxide adduct sulfate salts, alkylnaphthalenesulfonates, naphthalenesulfonic acid-formaldehyde condensate salts, and alkyldiphenylether disulfonates; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene glycerin fatty acid partial esters, polyoxyethylene glycol fatty acid esters, polyoxyethylene polyoxypropylene block polymers, and polyethylene glycol mono (styrylphenyl) ethers; further preferably a styrenated phenol alkylene oxide adduct sulfuric acid ester salt, an alkylnaphthalene sulfonate or a naphthalenesulfonic acid formaldehyde condensate salt; particularly preferred is a styrenated phenol alkylene oxide adduct sulfuric acid ester salt or a naphthalenesulfonic acid formaldehyde condensate salt.

Examples of the solvent include: aliphatic hydrocarbon solvents such as hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, heptane, nonane, octane, isooctane, and decane; aromatic hydrocarbon solvents such as benzene, toluene, xylene, cumene and ethylbenzene; ether solvents such as diethyl ether, diisopropyl ether, methyl tert-butyl ether, methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, diethyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tetrahydrofuran, 1, 3-dioxane, 1, 4-dioxane, and the like; ketone solvents such as dimethyl ketone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, diisopropyl ketone, diisobutyl ketone, and cyclohexanone; carbonate-based solvents such as dimethyl carbonate, diethyl carbonate, and ethylene carbonate; alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, isobutanol, sec-butanol, cyclohexanol, diacetone alcohol, 3-methoxy-3-methyl-1-butanol, ethylene glycol, and propylene glycol; ester-based solvents such as ethyl acetate, n-butyl acetate, isobutyl acetate, n-pentyl acetate, propylene glycol monomethyl ether acetate, and 3-methoxy-3-methyl-1-butyl acetate; nitrile solvents such as acetonitrile, and aliphatic amide solvents such as N, N-dimethylformamide, N-dimethylacetamide, alkoxy-N-isopropyl-propionamide, and hydroxyalkylamide; alicyclic amide solvents such as N-methyl-2-pyrrolidone and N-ethyl-pyrrolidone; water, and the like. These can be used alone in 1 or a combination of 2 or more.

The method for producing the composition for forming a light scattering body is not particularly limited, and examples thereof include: a method of adding and dispersing a hollow particle precursor and a light scattering particle to a resin composition.

Examples of the method for dispersing the hollow particle precursor and the light-scattering particles include conventionally known mixing and dispersing methods. In order to further reliably disperse the hollow particle precursors and the light scattering particles, it is preferable to perform a dispersion treatment using a dispersing machine.

Examples of the dispersing machine include: mixers such as a disperser, a homogenizer, a planetary mixer (PRIMIX corporation), a revolution and rotation mixer (for example, "debubbling and tara" manufactured by シンキー corporation); a homogenizer ("Clearmix" manufactured by M-Technique corporation); a media type dispersing machine such as a paint conditioner (manufactured by レッドデビル Co.), a ball MILL, a sand MILL ("DYNO-MILL" manufactured by シンマルエンタープライゼス Co.), an attritor, a bead MILL ("DCP Mill" manufactured by Eirich Co.), and Coball Mill; a wet jet mill (e.g., "ジーナス PY" manufactured by ジーナス, Starburst manufactured by Sugino Machine, and "Nanomizer" manufactured by Nanomizer); a non-medium disperser ("Clear SS-5" manufactured by M-Technique, Inc., and "MICROROS" manufactured by Nara machinery, Inc.); and a roller mill and the like.

< sheet-like laminate >

Fig. 2 and 3 are schematic cross-sectional views showing an embodiment of the sheet laminate. The sheet laminate 6 of the present embodiment shown in fig. 2 and 3 includes a base material 4, and a light scattering layer including the light scattering body 5 of the present embodiment provided on the base material 4. Fig. 2 is a diagram showing a case where the particle diameters of the hollow particles 1 and the light scattering particles 2 are smaller than the thickness of the light scattering body 5, and fig. 3 is a diagram showing a case where the particle diameters of the hollow particles 1 are larger than the thickness of the light scattering body 5. As shown in fig. 3, the hollow particles 1 and/or the light scattering particles 2 may protrude out of the resin medium 3.

The substrate is not particularly limited as long as it does not inhibit the optical properties of the sheet laminate, and specifically, there may be mentioned: soda-lime glass, lead glass, borosilicate glass, and the like; plastics such as polyester resins, polycarbonate resins, polyolefin resins, polyacrylic resins, cellulose resins, and polyvinyl resins; quartz; metal oxides such as aluminum oxide, titanium oxide, niobium oxide, tantalum oxide, indium tin oxide, zinc oxide, zirconium oxide, and cerium oxide; alloys such as steel, carbon steel, chromium-molybdenum steel, aluminum alloy, stainless steel alloy, copper alloy, titanium alloy, and the like; metals such as gold, silver, copper, zinc, iron, aluminum, platinum, lead, palladium, and the like; plant fibers such as cotton and hemp; animal fibers such as silk, wool, alpaca, angora rabbit hair (アンゴラ), kefir goat hair, and mohair; synthetic fibers such as rayon, polyacetate, Promix, nylon, polyester, polyacrylic, polyvinyl chloride, and polyurethane; inorganic fibers such as glass fibers, metal fibers, and carbon fibers.

When used as a transmission type screen, a transparent substrate is preferable. Specific examples of the transparent substrate include glass and plastic.

The thickness of the base material is not particularly limited, but is preferably 1 μm to 50mm, more preferably 20 μm to 30mm, from the viewpoint of strength and economy.

The light scattering layer includes the light scattering body of the present embodiment described above, and can be formed using a composition for forming a light scattering body.

The thickness of the light scattering layer is preferably 0.1 to 500 μm, more preferably 0.5 to 80 μm, from the viewpoint of excellent visibility and economy. The thickness of the light-scattering layer was measured using a micrometer (manufactured by ミツトヨ, trade name: MDH-25M).

The sheet-like laminate of the present embodiment may be provided with a known hard coat layer, an antistatic layer, an anti-fingerprint film layer, or a matte layer on at least one outermost surface thereof to improve the strength of the film.

The adhesive layer may be provided by applying an adhesive to the substrate side of the sheet laminate.

When a projection image is projected, the sheet laminate of the present embodiment can be used for either of a reflection type and a transmission type. In the case of the transmissive type, the substrate is not particularly limited as long as the optical characteristics are not impaired.

The sheet laminate of the present embodiment can be formed into a sheet laminate excellent in flame retardancy by adding an appropriate amount of a flame retardant such as antimony trioxide, antimony pentoxide, aluminum hydroxide, magnesium hydroxide, melamine cyanurate, BestBoron, or Soufa to a light-scattering-body-forming composition and using flame-retardant vinyl chloride, a flame-retardant polyethylene terephthalate (ポリエチテンレテフタレート) film, a polyphenylene sulfide film, an aromatic polyamide film, or a flame-retardant polycarbonate film as a base material.

The sheet laminate of the present embodiment can be produced, for example, by a method including the steps of: coating a composition for forming a light scattering body, which contains a composition for a resin, a hollow particle precursor, and light scattering particles, on a base material; and a step of drying or curing the coating film. In addition, another method includes a method including a step of laminating a sheet-like light scattering body on a base material.

The method of applying the light-scattering body-forming composition is not particularly limited, and may be appropriately selected depending on the shape of the release substrate or the substrate, and examples thereof include: a slide droplet (slide bead) system, a slide curtain (slide curve) system, an extrusion system, a slit die system, a gravure roll system, an air knife system, a blade coating system, a bar coating system, and the like.

As a method for drying or curing the formed coating film, a method of heating with a warm air dryer, an infrared dryer, or the like can be used. When the resin composition is an aqueous emulsion, the resin can be cured by heating the water dispersed in the emulsion with a warm air dryer, an infrared dryer, or the like to evaporate the water contained in the coating film. When the resin composition contains a monomer and a polymerization initiator, the coating film may be heated as necessary to remove the solvent in the coating film, and then irradiated with an active energy ray such as ultraviolet ray, electron beam, infrared ray, visible ray, X-ray, α -ray, γ -ray, or heavy particle ray to polymerize the monomer and polymerize it to form a polymer, thereby curing the coating film.

The thickness of the coating film of the light scattering material forming composition is preferably 0.1 to 500 μm, more preferably 0.5 to 80 μm, in terms of visibility and economy, as the thickness of the light scattering material (for example, the thickness of the light scattering material 5) after drying.

When the light scattering body is formed on the release substrate, the light scattering body may be peeled off from the release substrate to obtain a sheet-like light scattering body. The method of peeling from the release substrate is not particularly limited, and examples thereof include seal peeling, physical peeling, and addition of a peeling agent.

Examples of the method of laminating the sheet-like light scattering body formed on the release substrate to the substrate include bonding with an optical adhesive, and thermal fusion bonding.

< projection Screen >

The projection screen of the present embodiment includes the light scattering body of the present embodiment or the sheet laminate of the present embodiment. The projection screen of the present embodiment may be a transmission type screen capable of recognizing an image from the side of transmitting to the light source, or may be a reflection type screen capable of recognizing an image from the side of reflecting to the light source.

The projection screen of the present embodiment may be configured by a light scattering body or a sheet laminate alone, but preferably has a function of fixing the light scattering body or the sheet laminate in space when an image is projected by a projection source.

Specifically, a fixing member may be attached to the entire upper portion or a part of the sheet-like stacked body. In order to prevent image blurring or distortion, the fixing function is preferably capable of maintaining the sheet laminate in a flat state without bending.

The projection screen of the present embodiment preferably includes a storage means capable of storing the sheet laminate in a roll shape. The storage means may be a take-up type storage device. In this case, the image projection unit of the sheet laminate can be protected when the projection screen is not used, and storage, portability, transportability, and the like can be improved.

The projection screen of the present embodiment may have a weight in a lower portion of the sheet laminate in order to suppress the projection surface from being curved or deformed by wind, vibration, or the like. By applying a force of 1kg to 500kg as a weight, the flatness of the image projection surface is easily maintained, and distortion of the projected image is eliminated.

The projection screen of the present embodiment may be a projection screen in which a light scattering body or a sheet-like laminated body is provided on a substrate having a curved surface. In this case, the light scattering body or the sheet-like laminate may be bonded or adhered to the curved base material, or the light scattering body may be formed by directly applying the above-mentioned composition for forming a light scattering body to the surface of the curved base material.

In this case, a transmission type curved transparent screen or a reflection type curved transparent screen suitable for a curved image, projection of a stereoscopic image, and projection onto a stereoscopic curved surface can be configured.

The light scattering body or the sheet laminate of the present embodiment can be used as a light diffusion sheet capable of reducing the directivity of light.

Further, the light scattering body or the sheet-like laminated body of the present embodiment can be used as a composite light diffusion sheet for further amplifying the light scattering effect by forming it on another light diffusion sheet. For example, when an LED (light emitting diode) or an LD (laser diode) is used as a light source for illumination, the use of the composite light scattering sheet can effectively scatter light, increase the scattering angle to an angle suitable for use, and uniformly scatter illumination light indoors or outdoors.

A light intensifier for illumination can be constituted using the light scattering body or the sheet laminate of the present embodiment. By using a light scattering body or a sheet-like laminate as a light intensifier for illumination, light scattering can be efficiently performed with an extremely simple configuration.

The sheet laminate or the projection screen of the present embodiment may be used for a vehicle member. For example, a sheet laminate or a projection screen may be bonded to the surfaces of the side window and the rear window to provide a function of displaying an image on the side window and the rear window.

The sheet laminate or the projection screen of the present embodiment may be used for a building member. For example, a sheet laminate or a projection screen may be attached to a transparent window material, and an image may be projected by a projector to be used as an advertisement or information provision for a store.