JP2019120739A - Transmission type screen - Google Patents

Abstract

To provide a transmission type screen that provides high brightness to a video projected from a projector, provides a very wide viewing angle to the video, and has good breakability.SOLUTION: A transmission type screen has a light diffusion layer at least on one face of a substrate; the substrate is paper having a degree of transparency of 50% or more, and the light diffusion layer contains light-diffusive fine particles having an average primary particle diameter of 2.75 μm or less and single particle dispersibility and xerogel.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transmissive screen having high luminance of an image projected from a projector, a very wide viewing angle of the image, and good breakability.

  At present, a so-called rear projection type transmission screen, in which an image projected from a projector is viewed from the opposite side of the projector across the screen, is widely used in place of advertising media such as posters, signs, signs, etc. is there. In recent years, the transparent screen has attracted much attention as digital signage that can project digital content that can be changed instantly, not only static but also dynamic postings, on a large screen, which does not require repositioning, and that can be dynamically displayed. There is.

  Such a rear projection type transmissive screen is often used as a so-called window display application, for example, as a digital signage that is used as a large screen screen by attaching it to a show window or the like of a store. As a rear projection type transmission screen, a screen using a polarizing film, a Fresnel lens sheet, a lenticular lens sheet or the like (for example, Patent Document 1) or a screen using a light transmitting bead having high brightness and high contrast (for example, Patent document 2) is proposed. In addition, by providing a light diffusion layer containing porous particles, a transmission screen with high resolution, low cost, and high durability (for example, Patent Document 3) is proposed, or light diffusing fine particles and a resin binder are used. Containing a part of the light diffusing fine particles from the light diffusing layer to have a haze of 80% or more, a total light transmittance of 60% or more, and a specular gloss of at least one surface of 10% or less A transmissive screen of U.S. Pat. In such applications, plastic films such as polyethylene terephthalate that do not break are used so as to withstand long-term use.

  On the other hand, rear projection type transmissive screens may be used in applications that are used in a very short time, such as display screens at event booths, and they can be removed in a relatively short time. Unlike the rear projection type transmission screen using the above-mentioned plastic film, it is desired that it be easily broken and easily discarded like paper. In addition, when it is used in stage rendition etc., performers are able to create weird effects such as breaking the screen on which the image is shown, and so on, so it is possible to use so-called Japanese paper and shoji paper which are not transmissive screens. Breakable paper may be used.

  However, some of such papers do not easily transmit light, and there is a problem that sufficient brightness can not be obtained when used as a rear projection type transmission screen. In addition, in exhibitions and stage performances at events, it is necessary that the brightness of the image projected from the projector is high and the viewing angle of the image is very wide, but such paper has a problem that the viewing angle is narrow. The

Japanese Patent Application Laid-Open No. 6-165095 WO 99/050710 pamphlet JP, 2006-119318, A JP 2005-024942 A

  An object of the present invention is to provide a transmissive screen having high luminance of an image projected from a projector, a very wide viewing angle of the image, and good breakability.

The above-mentioned subject is achieved by the following invention.
A transmission screen having a light diffusion layer on at least one surface of a substrate, wherein the substrate is a paper having a transparency of 50% or more, and the light diffusion layer has an average primary particle diameter of 2.75 μm. A light transmission screen comprising the following single particle dispersible light diffusing fine particles and a xerogel.

  According to the present invention, it is possible to provide a transmissive screen having high luminance of an image projected from a projector, a very wide viewing angle of the image, and good breakability.

Schematic sectional drawing which shows one Example of the transmissive screen of this invention Schematic sectional drawing which shows the other Example of the transmissive screen of this invention Schematic sectional drawing which shows the other Example of the transmissive screen of this invention Schematic sectional view showing a conventional example of a transmission screen Schematic sectional view showing another conventional example of transmission screen

  The present invention will be described in detail below.

  1 to 3 show schematic cross-sectional views showing one embodiment or another embodiment of the transmission screen of the present invention, and FIGS. 4 and 5 show schematic cross-sectional views of a conventional example of the transmission screen. The substrate 5a in the present invention is not a plastic film 5b as shown in FIG. 4 but a breakable paper. In the transmission screen of the present invention, the light diffusing layer 3 containing the light diffusing fine particles 2 and the xerogel 4 is provided only on one side of the substrate 5a as shown in FIG. 1 or the substrate 5a as shown in FIG. A light diffusing layer 3 containing light diffusing fine particles 2 and xerogel 4 on both sides of the adhesive layer 6 on the opposite side to the light diffusing layer 3 containing light diffusing fine particles 2 and xerogel 4 as shown in FIG. A configuration provided is also possible. In addition, FIG. 5 is the structure which provided the light-diffusion layer 3 which does not contain the xerogel 4 using the base material 5a which can be fractured | ruptured. Although not shown, it is also possible to provide an adhesive layer 6 on the light diffusion layer 3 of the transmission screen of FIG. In addition, on the adhesive layer 6, the separate base material 7 is preferably provided for the purpose of protection of this.

  The "transmission type" of the transmission screen in the present invention refers to a screen having a total light transmittance of more than 50% as defined in JIS-K7105 in a state where the separate base material is removed.

  The base material in the present invention is characterized by being a paper having a transparency of 50% or more. The transparency in the present invention is a value represented by 100- (opacity value), and the opacity value is the opacity (%) measured by method A of JIS P 8138.

  The base material in the present invention is not particularly limited as long as it is a paper having a transparency of 50% or more, and wood pulp, fillers, sizing agents, paper strengthening agents, dyes, etc. are usually used as raw materials used in papermaking. Manufactured using. Therefore, for example, it is characterized by having a good breaking property different from plastic films such as polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, acrylic, acetyl cellulose, polyvinyl chloride and the like. Examples of such paper include high-grade paper, glassine paper, cast paper, coated paper, resin-impregnated paper, typewriter paper, condenser paper, tracing paper, impregnated tracing paper, or Japanese paper, among which , Tracing paper and impregnated tracing paper are preferred. If the transparency of the paper is less than 50%, high luminance can not be obtained.

  The tracing paper referred to in the present invention is a paper also called natural trepe or natural trepe, and natural trepe is a paper which is paper-made so that pulp fibers are highly beaten to reduce gaps between the pulps. Racing paper is a paper in which common high-quality paper is impregnated with a transparent resin having the same refractive index as cellulose.

The basis weight of the paper in the present invention is not particularly limited as long as the transparency is 50% or more, but is preferably 10 to 400 g / m ² , more preferably 40 to 300 g / m ² , and most preferably 50 It is -250 g / m < ² >. If the basis weight of the paper is too low, the light diffusion layer is likely to be wrinkled when forming the light diffusion layer, and handling may be difficult if the basis weight of the paper is too high.

  The thickness of the paper in the present invention is not particularly limited as long as the transparency is 50% or more, but is preferably 10 to 400 μm, more preferably 40 to 300 μm, and most preferably 50 to 250 μm. When the thickness of the paper is too thin, the light diffusion layer is likely to be wrinkled and difficult to handle when the light diffusion layer is provided, and when the thickness of the paper is too thick, the breaking property may be easily deteriorated.

  The light diffusion layer in the present invention contains single particle dispersible light diffusing fine particles having an average primary particle diameter of 2.75 μm or less, and xerogel. Here, single-particle-dispersible light diffusing fine particles having an average primary particle diameter of 2.75 μm or less are particles in which the primary particles themselves form dispersed particles. When light-diffusing fine particles having a single-particle dispersive property with an average primary particle diameter exceeding 2.75 μm are used, the brightness and resolution of the image projected from the projector become low. The average primary particle diameter of the single particle dispersible light diffusing fine particles is more preferably 1.25 μm or less, and the lower limit is 0.10 μm from the viewpoint of light diffusing property.

  The average primary particle size in the present invention can be measured by photography with a transmission electron microscope, but in the case of light diffusing fine particles of single particle dispersibility, a laser scattering type particle size distribution analyzer (for example, The number median diameter can also be measured using Horiba LA 910).

  In general, when light diffusing fine particles are applied to a light transmitting support, a resin binder for binding the light diffusing fine particles is required. The coating liquid containing the light diffusing fine particles and the resin binder is diluted with an organic solvent or water for the purpose of viscosity adjustment etc. for securing the coating property and is coated / dried on a light transmitting support, or photocurable It is common practice to apply a resin or an electron beam curable resin as a resin binder without using any solvent. In the light diffusion layer coated by such a method, the refractive index of the light diffusing fine particle relative to the resin binder is generally approximately 1.50 because both the refractive index of the resin binder and the light diffusing fine particle are around 1.50. It is low and it is difficult for efficient light diffusion to occur. On the other hand, in the present invention, by causing the light diffusing fine particles to be supported on the xerogel, voids (air with a refractive index of 1.0) of the xerogel exist on the surface of the light diffusing fine particles, and the relative refraction of the light diffusing fine particles with respect to air. Since the rate becomes very high, efficient light diffusion of the light diffusing fine particles becomes possible, and it becomes possible to provide a transmissive screen having a high viewing angle and a high luminance of the image projected from the projector.

  In addition, in the patent documents 3 and 4 mentioned above, only the light-diffusion layer which hold | maintained light-diffusing microparticles | fine-particles with the resin binder is described, Comprising: The light-diffusion layer of this invention which carry | supports light-diffusing microparticles on xerogel Is essentially different.

  The single particle dispersible light diffusing fine particles having the above-described specific average primary particle diameter, which the light diffusing layer in the present invention contains, may be inorganic fine particles and organic fine particles as long as they have a light diffusing ability. Although it can be used, it is preferable to use organic fine particles.

  The light diffusivity of the light diffusing fine particles depends on the specific surface area in addition to the relative refractive index described above. The specific surface area depends on the average primary particle size of the light diffusing fine particles, and in the case of light diffusing fine particles of single particle dispersibility, it can be easily calculated from the average primary particle size and specific gravity.

  Inorganic fine particles used as light diffusing fine particles include silica, alumina, rutile titanium dioxide, anatase titanium dioxide, zinc oxide, zinc sulfide, lead white, antimony oxides, zinc antimonate, lead titanate, potassium titanate, Zirconium oxide, cerium oxide, hafnium oxide, tantalum pentoxide, niobium pentoxide, yttrium oxide, chromium oxide, tin oxide, molybdenum oxide, ATO, ITO, silicate glass, phosphate glass, borate glass, etc. There are oxidized glass and the like, and these complex oxides and complex sulfides can be widely used. In addition, in the case of inorganic fine particles having photocatalytic activity such as titanium dioxide and zinc oxide, those very thin on the surface of the inorganic fine particles and coated with silica, alumina, boron or the like can also be used. In addition, even when composite particles composed of inorganic fine particles and a small amount of organic polymer (having a ratio of organic fine particles of less than 50% by mass) are used, they can be regarded substantially as inorganic fine particles and used.

  Examples of the organic fine particles used as the light diffusing fine particles include acrylic polymers, styrene-acrylic copolymers, vinyl acetate-acrylic copolymers, vinyl acetate polymers, ethylene-vinyl acetate copolymers, chlorinated polyolefin polymers Ethylene-vinyl acetate-acrylic multicomponent copolymer, SBR, NBR, MBR, carboxylated SBR, carboxylated NBR, carboxylated MBR, polyvinyl chloride, polyvinylidene chloride, polyester, polyolefin, polyurethane, polymethacrylate, poly Tetrafluoroethylene, methyl polymethacrylate, polycarbonate, polyvinyl acetal resin, rosin ester resin, episulfide resin, epoxy resin, silicone resin, silicone-acrylic resin, melamine resin, etc. It can be chosen widely from the. Further, it is also possible to use one in which the surface of fine particles such as melamine resin and acrylic resin is coated with inorganic fine particles such as silica. Further, even when composite particles comprising such organic fine particles and a small amount of inorganic fine particles (in which the ratio of the inorganic fine particles is less than 50% by mass) are used, they can be regarded substantially as organic fine particles. Those obtained by introducing a sulfur atom for the purpose of increasing the refractive index in the monomers of these polymers, and those obtained by introducing a fluorine substituent for the purpose of improving the weather resistance or reducing the refractive index can also be used.

The coating amount of the single particle dispersible light diffusing fine particles in the present invention is preferably 0.1 to 15.0 g / m ² , more preferably 0.3 to 10.0 g / m ² .

  In addition, the single particle dispersible light diffusing fine particles in the present invention can be used singly or in combination of two or more.

  Next, the xerogel which the light-diffusion layer of this invention has is demonstrated. The light diffusion layer of the present invention holds light diffusing fine particles by xerogel.

  The xerogel referred to in the present invention is a gel which loses a solvent inside and has a network structure having voids due to evaporation or the like, and the porosity of the light diffusion layer in which the light diffusing fine particles are held by xerogel is 50% or more Is preferred.

The porosity is defined by the following equation. Here, the void volume V is measured and processed using a mercury porosimeter (measuring device name Autopore II 9220 manufacturer micromeritics instrument corporation), and the cumulative pore volume (ml / g) from 3 nm to 400 nm in pore radius in the light diffusion layer Then, it can be determined as a value per unit area (square meter) by multiplying the dry solid content (g / square meter) of the light diffusion layer. The thickness T of the coated layer can be obtained by photographing the cross section of the light diffusion layer with an electron microscope and measuring the length.
P = (V / T) x 100 (%)
P: porosity (%)
V: void volume (ml / m ² )
T: Coating thickness (μm)

  The xerogel of the present invention is preferably composed of inorganic fine particles and a resin binder, and more preferably composed of inorganic fine particles having an average primary particle diameter of 18 nm or less and a resin binder. When the average primary particle diameter exceeds 18 nm, the brightness of the image projected from the projector may be low. Moreover, it is preferable that the inorganic fine particle which comprises the xerogel of this invention has a secondary aggregation particle diameter whose average secondary particle diameter is 500 nm or less. When the average secondary particle diameter exceeds 500 nm, the light transmittance of the light diffusion layer may be lowered, and the luminance of the image projected from the projector may be lowered.

  The inorganic fine particles constituting the xerogel in the present invention include various known fine particles such as amorphous synthetic silica, alumina, alumina hydrate, calcium carbonate, magnesium carbonate, titanium dioxide, etc., since high porosity can be obtained. Amorphous synthetic silica, alumina or alumina hydrate is preferred.

  Amorphous synthetic silica can be roughly classified into wet silica, fumed silica, and others depending on the production method. Wet silica is further classified into precipitated silica, gel silica and sol silica according to the production method. Precipitated silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions, and the particle-grown silica particles are coagulated and precipitated, and then produced through processes of filtration, water washing, drying, pulverization and classification. As precipitated silica, for example, it is commercially available from Tosoh Silica Co., Ltd. as Nip Seal (registered trademark), and from Tokuyama Co., Ltd. as Toxeal (registered trademark). Gel method silica is produced by reacting sodium silicate and sulfuric acid under acidic conditions. During ripening, the microparticles dissolve and reprecipitate so as to bind other primary particles, so that distinct primary particles disappear and form relatively hard agglomerated particles having an internal void structure. For example, they are commercially available as Nipgel (registered trademark) from Tosoh Silica Corporation, and Syloid (registered trademark) and Shirojet (registered trademark) from Grace Japan Corporation. Sol method silica is also called colloidal silica, and is obtained by heat aging a silica sol obtained by double decomposition of sodium silicate with an acid or the like or passing through an ion exchange resin layer, for example, Snowtex (registered trademark) from Nissan Chemical Industries, Ltd. It is marketed as

  Gas phase silica is also called dry method as opposed to wet method and is generally made by flame hydrolysis. Specifically, a method of burning silicon tetrachloride with hydrogen and oxygen is generally known, but instead of silicon tetrachloride, silanes such as methyltrichlorosilane and trichlorosilane are used alone or in combination. It can be used in a mixed state with Vapor phase silica is commercially available from Nippon Aerosil Co., Ltd. as Aerosil (registered trademark), and from Tokuyama Co., Ltd. as QS type.

In the present invention, fumed silica can be preferably used. The average primary particle size of the fumed silica used in the present invention is preferably 18 nm or less, and the average primary particle size is 3 to 16 nm and mentioned above in order to obtain visibility from both sides with higher balance. It is to use one having a specific surface area of 100 m ² / g or more according to the BET method.

  The fumed silica is preferably dispersed in the presence of a cationic compound. Thereby, a light diffusion layer having a high porosity is obtained, and a high viewing angle is obtained. As a dispersion method, vapor phase silica and dispersion medium are pre-mixed by ordinary propeller stirring, turbine type stirring, homomixer type stirring etc., and then media mill such as ball mill, bead mill, sand grinder etc., high pressure homogenizer, ultra high pressure Dispersion is preferably performed using a pressure-type disperser such as a homogenizer, an ultrasonic disperser, a thin film swirl disperser, or the like.

  In the present invention, wet method silica in which the average secondary particle diameter is pulverized to 500 nm or less can also be preferably used. As the wet method silica to be used here, precipitated silica or gel silica is preferable, and precipitated silica is particularly preferable. The wet process silica particles used in the present invention are preferably wet process silica particles having an average primary particle size of 18 nm or less and an average agglomerated particle size of 5 to 50 μm, and these are finely pulverized in the presence of a cationic compound. It is preferable to use the wet process silica particle.

  As alumina used in the present invention, γ-alumina which is γ-type crystal of aluminum oxide is preferable, and among them, δ group crystal is preferable. Although γ-alumina can make primary particles as small as about 10 nm, secondary particles of several thousand to several tens of thousands of nm are usually averaged by the ultrasonic wave, high-pressure homogenizer, counter collision type jet crusher, etc. What was grind | pulverized to a particle diameter of 500 nm or less, preferably about 20-300 nm can be used.

Alumina hydrate of the present invention is represented by the structure formula of _{Al 2 O 3 · nH 2 O} (n = 1~3). Alumina hydrate can be obtained by known methods such as hydrolysis of aluminum alkoxide such as aluminum isopropoxide, neutralization with alkali of aluminum salt, hydrolysis of aluminate, and the like.

  The above-mentioned alumina and alumina hydrate used in the invention are used from the form of dispersion dispersed by known dispersants such as acetic acid, lactic acid, formic acid and nitric acid.

  Two or more types of inorganic particles can be used in combination among the above-mentioned inorganic particles. For example, combined use of pulverized wet silica and fumed silica, combined use of finely pulverized wet silica and alumina or alumina hydrate, combined fumed silica and alumina or alumina hydrate can be mentioned. . The ratio in the case of this combination is preferably in the range of 7: 3 to 3: 7 in any mode.

  In the present invention, the resin binder used together with the inorganic fine particles constituting the xerogel is not particularly limited, but a hydrophilic resin binder having high transparency is preferably used. For example, polyvinyl alcohol, gelatin, polyethylene oxide, polyvinyl pyrrolidone, polyacrylic acid, polyacrylamide, polyurethane, dextran, dextrin, carrageenan (κ, ι, λ, etc.), agar, pullulan, water-soluble polyvinyl butyral, hydroxyethyl cellulose, carboxymethyl cellulose Etc. It is also possible to use two or more of these hydrophilic resin binders in combination. Preferred hydrophilic resin binders are fully or partially saponified polyvinyl alcohol and cationically modified polyvinyl alcohol.

  The content of the resin binder constituting the xerogel is preferably 3 to 100% by mass, more preferably 5 to 85% by mass, still more preferably 10 to 70% by mass with respect to the inorganic fine particles constituting the xerogel . As a result, the brightness of the image projected from the projector and the brightness unevenness can be compatible at a higher level. Moreover, it is preferable that content of the light diffusable microparticles | fine-particles mentioned above is 30-200 mass% with respect to the inorganic microparticle which comprises xerogel.

  A light diffusing agent can be used together with a resin binder as needed. Specific examples of the hardening agent include formaldehyde, aldehyde compounds such as glutaraldehyde, diacetyl, ketone compounds such as chloropentanedione, bis (2-chloroethyl) urea, 2-hydroxy-4,6-dichloro-1 3,5-Triazine, a compound having a reactive halogen as described in US Pat. No. 3,288,775, a divinyl sulfone, a compound having a reactive olefin as described in US Pat. No. 3,635,718, N-methylol compounds as described in U.S. Pat. No. 2,732,316, isocyanates as in U.S. Pat. No. 3,103,437, U.S. Pat. No. 3,017,280, U.S. Pat. No. 2,983, Aziridine compounds as described in No. 611, carbodiimide type compounds as described in US Pat. No. 3,100,704 Epoxy compounds as described in US Pat. No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, chromium alum, zirconium sulfate, borax, boric acid, boric acid salts and the like There are inorganic crosslinking agents and the like, and these can be used alone or in combination of two or more.

Dry solid coating amount of the light diffusing layer is preferably in the range of 1 to 50 g / ^{m 2,} more preferably in the range of 3~40g / ^{m 2,} in particular in the range of 5 to 30 g / ^{m 2} is preferred. In the light diffusion layer, cationic polymers, preservatives, surfactants, coloring dyes, coloring pigments, UV absorbers, antioxidants, dispersants for pigments, antifoaming agents, leveling agents, fluorescent brighteners, viscosity Stabilizers, pH adjusters and the like can also be added.

  The light diffusion layer may be composed of two or more layers, and may be provided on one side and both sides of the substrate. In this case, the configurations of the light diffusion layers may be the same as or different from one another. In the case where there are a plurality of light diffusion layers, the light diffusion fine particles can be contained in at least one light diffusion layer.

  In the present invention, various known coating methods can be used as the coating method used for coating the light diffusion layer. For example, there are a slide bead system, a slide curtain system, an extrusion system, a slot die system, a gravure roll system, an air knife system, a blade coating system, a rod bar coating system and the like.

  In addition, an adhesive layer using a synthetic resin adhesive such as acrylic, silicone, urethane, rubber, etc., which is generally used, can be provided on the surface of the light diffusion layer of the substrate or the opposite surface. For protection, known separate substrates such as films and papers can be provided. When using the transmission screen, the separate substrate may be peeled off and the transmission screen may be used by adhering to the adherend substrate. Although there is no restriction | limiting in particular as a to-be-adhered base material, What does not prevent the light transmittance and the fracture property of a transmissive screen is preferable.

  The transmission screen of the present invention can also be used by projecting the image of the projector from either the light diffusion layer side or the opposite side.

  EXAMPLES Hereinafter, the present invention will be described in detail by way of examples, but the contents of the present invention are not limited to the examples. In addition, a part represents the mass part of solid content or a substantial component.

Example 1
The light diffusion layer coating solution 1 of the following composition was coated on one side of a tracing paper having a basis weight of 200 g / m ² and a transparency of 60% as a substrate so that the solid content coating amount would be 18.5 g / m ² The coating was applied using an apparatus, and hot air of 10 ° C. and 50 ° C. was sequentially blown and dried to produce the transmission screen of Example 1.

<Preparation of Silica Dispersion 1>
After adding 4 parts of dimethyldiallyl ammonium chloride homopolymer (molecular weight 9,000) and 100 parts of gas phase method silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g) to water to prepare a preliminary dispersion, high pressure homogenizer To prepare a silica dispersion having a solid concentration of 20%. The average secondary particle size was 80 nm when measured using a Horiba LA 910.

Light Diffusion Layer Coating Solution 1
Silica dispersion 1 (as silica solid content) 100 parts polyvinyl alcohol 23 parts (saponification degree 88%, average polymerization degree 3500)
4 parts of boric acid 0.3 parts of nonionic surfactant (polyoxyethylene alkyl ether)
Light diffusing fine particles 6.0 parts (Optobeads (registered trademark) 500S: manufactured by Nissan Chemical Industries, Ltd., silica, melamine resin composite fine particles (mainly melamine resin), single particle dispersibility, average primary particle diameter 0.5 μm , True specific gravity 2.2, refractive index 1.65)
It adjusted with water so that the whole solid concentration might be 12%.

(Example 2)
A transmission screen of Example 2 was produced in the same manner as in Example 1 except that the base material of Example 1 was changed to a tracing paper having a basis weight of 85 g / m ² and a transparency of 70%.

(Example 3)
A transmission type screen of Example 3 was produced in the same manner as in Example 1 except that the light diffusion layer coating solution 1 of Example 1 was replaced with the following light diffusion layer coating solution 2.

Light Diffusion Layer Coating Solution 2
Silica dispersion 1 (as silica solid content) 150 parts polyvinyl alcohol 23 parts (saponification degree 88%, average polymerization degree 3500)
4 parts of boric acid 0.3 parts of nonionic surfactant (polyoxyethylene alkyl ether)
15.0 parts of light diffusing fine particles (Optobeads 2000M: manufactured by Nissan Chemical Industries, Ltd., silica, melamine resin composite fine particles (mainly melamine resin), average primary particle diameter 2.0 μm, true specific gravity 2.2, refractive index 1 .65)
It adjusted with water so that the whole solid concentration might be 12%.

(Example 4)
A transmission screen of Example 4 was produced in the same manner as in Example 1 except that the light diffusion layer coating solution 1 of Example 1 was replaced with the light diffusion layer coating solution 3 described below.

Light Diffusion Layer Coating Solution 3
Silica dispersion 1 (as silica solid content) 150 parts polyvinyl alcohol 23 parts (saponification degree 88%, average polymerization degree 3500)
16 parts of boric acid 0.3 parts of nonionic surfactant (polyoxyethylene alkyl ether)
Single-particle dispersible light diffusing fine particles 10.0 parts (SSX-101: Cross-linked poly (methyl methacrylate), manufactured by Sekisui Plastics Co., Ltd., single particle dispersity, average primary particle diameter 1.0 μm, true specific gravity 1.19, refractive index 1.49)
It adjusted with water so that the whole solid concentration might be 12%.

(Comparative example 1)
A transmission screen of Comparative Example 1 was produced in the same manner as Example 1, except that the base material of Example 1 was changed to tracing paper having a basis weight of 65 g / m ² and a transparency of 40%.

(Comparative example 2)
A transmission screen of Comparative Example 2 is produced in the same manner as in Example 1 except that the base material of Example 1 is changed to a coated paper having a basis weight of 120 g / m ² and a transparency of 6% (Mitsubishi Paper Mills, Pearl Deluxe). did.

(Comparative example 3)
A transmissive screen of Comparative Example 3 was produced in the same manner as in Example 1 except that the base material of Example 1 was changed to a polyethylene terephthalate film having a basis weight of 100 g / m ² and a transparency of 95%.

(Comparative example 4)
A transmissive screen of Comparative Example 4 was produced in the same manner as in Example 1 except that the light diffusion layer coating solution 1 of Example 1 was replaced with the light diffusion layer coating solution 4 described below.

Light Diffusion Layer Coating Solution 4
Silica dispersion 1 (as silica solid content) 100 parts polyvinyl alcohol 23 parts (saponification degree 88%, average polymerization degree 3500)
4 parts of boric acid 0.3 parts of nonionic surfactant (polyoxyethylene alkyl ether)
15.0 parts of light diffusing fine particles (Optobeads 3500M: manufactured by Nissan Chemical Industries, Ltd., silica, melamine resin composite fine particles (mainly melamine resin), single particle dispersibility, average particle diameter 3.5 μm, true specific gravity 2. 2, refractive index 1.65)
It adjusted with water so that the whole solid concentration might be 12%.

(Comparative example 5)
A transmissive screen of Comparative Example 5 was produced in the same manner as in Example 1 except that the light diffusion layer coating solution 1 of Example 1 was replaced with the following light diffusion layer coating solution 5.

Light Diffusion Layer Coating Liquid 5
Silica dispersion 1 (as silica solid content) 100 parts polyvinyl alcohol 23 parts (saponification degree 88%, average polymerization degree 3500)
4 parts of boric acid 0.3 parts of nonionic surfactant (polyoxyethylene alkyl ether)
Light diffusing fine particles 15.0 parts (SBX-12: manufactured by Nissan Chemical Industries, Ltd., silica, melamine resin composite fine particles (mainly melamine resin), single particle dispersibility, average particle diameter 12.0 μm, true specific gravity 2. 2, refractive index 1.55)
It adjusted with water so that the whole solid concentration might be 12%.

(Comparative example 6)
A transmissive screen of Comparative Example 6 was produced in the same manner as in Example 1 except that the light diffusion layer coating solution 1 of Example 1 was replaced with the following light diffusion layer coating solution 6.

Light Diffusion Layer Coating Liquid 6
Silica dispersion 1 (as silica solids) 100 parts polyvinyl alcohol 60 parts (saponification degree 88%, average polymerization degree 3500)
4 parts of boric acid 0.3 parts of nonionic surfactant (polyoxyethylene alkyl ether)
Amorphous (not single particle dispersible) light diffusing fine particles 15.0 parts (P-78A: manufactured by Mizusawa Chemical Industry Co., Ltd., average secondary particle diameter 6.0 μm)
It adjusted with water so that the whole solid concentration might be 12%.

(Comparative example 7)
A transmissive screen of Comparative Example 7 was produced in the same manner as in Example 1 except that the light diffusion layer coating solution 1 of Example 1 was replaced with the light diffusion layer coating solution 7 described below.

Light Diffusion Layer Coating Liquid 7
Alkali-treated gelatin 100 parts nonionic surfactant 0.3 parts (polyoxyethylene alkyl ether)
Light diffusing fine particles 6.0 parts (Optobeads 500S)
It adjusted with water so that the whole solid concentration might be 12%.

(Comparative example 8)
The substrate of Example 1 was used as the transmission screen of Comparative Example 8.

  When the total light transmittance defined in JIS-K 7105 of the transmission screens of Examples 1 to 4 and Comparative Examples 1 to 8 obtained was measured, Examples 1 to 4 and Comparative Examples 3 to 8 It was 50% or more, and Comparative Examples 1 and 2 were less than 50%. In addition, it is calculated from the void volume of the light diffusion layer measured using the mercury porosimeter of the transmission screen of Examples 1 to 4 and Comparative Examples 1 to 6 and the thickness measured by electron microscope observation of the cross section of the light diffusion layer. The void ratio of the light diffusion layer of Comparative Example 7 was 0%.

  The transmission screens of Examples 1 to 4 and Comparative Examples 1 to 8 obtained were cut into A3 size, and attached to a transparent acrylic plate surface of 5 mm thickness with a tape with the light diffusion layer surface outside. A transmission screen attached to a transparent acrylic plate is vertically stood, and a digital projector (MP 515ST, manufactured by BenQ) actually projects an image parallel to the vertical line of the screen from the light diffusion layer side, and from the opposite side to the projector The image projected on the transmissive screen was observed.

<Brightness>
The image was visually observed and evaluated according to the following evaluation criteria.
:: The brightness of the image was very high, and the detail was clearly visible.
:: Although slightly inferior to the above ◎, the brightness of the image is high, and the detail was clearly visible.
Δ: The luminance of the image was a little low, and it was difficult to see the details.
X: The brightness of the image was low, and it was difficult to see the details.

<Viewing angle>
From the side opposite to the projector, the viewing angle was changed from 0 ° to 90 ° with respect to the vertical line of the screen and observed and evaluated according to the following evaluation criteria.
:: The image can be sufficiently confirmed at all angles and the viewing angle is very wide.
○: slightly inferior to the above ◎, but the image can be confirmed at all angles and the viewing angle is wide.
Fair: It is difficult to confirm the image at a high viewing angle near 90 °.
X: It is difficult to confirm an image at a high viewing angle near 90 °.

<Breakability>
The transmission type screens of Examples 1 to 4 and Comparative Examples 1 to 8 obtained were broken with a hand in the coating direction and the direction perpendicular thereto, and the degree of breakage was visually evaluated based on the following criteria.
○: It was possible to break easily.
Δ: A slight force was required to break.
X: It did not break.

  From the results of Table 1, it can be seen that the transmission screen of the present invention can provide a transmission screen having high luminance of the image projected from the projector, a very wide viewing angle of the image, and good breakability.

1 transmission screen 2 light diffusing fine particle 3 light diffusing layer 4 xerogel 5a substrate (paper)
5b Base material (plastic film)
6 Adhesive layer 7 Separate base material

Claims (1)

A transmission screen having a light diffusion layer on at least one surface of a substrate, wherein the substrate is a paper having a transparency of 50% or more, and the light diffusion layer has an average primary particle diameter of 2.75 μm. A light transmission screen comprising the following single particle dispersible light diffusing fine particles and a xerogel.