JP6691809B2 - Video projection system - Google Patents

Description

  The present invention relates to an optical element used in a video projection system including a video projection unit. It also relates to a video projection system comprising the optical element.

  Conventionally, when projecting an image, it is general that an image projection unit projects image light onto an image projection object such as a screen and an observer observes the image. In recent years, there has been an increasing demand for project display of product information, advertisements, etc. on a show window of a department store or a transparent partition of an event space by using a video projection system including such a video projection unit and a video projection object. There is. However, there is a problem in that the image light projected by the image projection unit is reflected by the surface of the screen and reaches an object other than the image projection object such as the ceiling or the rear wall, and the image is reflected. .. In such a case where the image is reflected on the ceiling, the brightness is conspicuous when the room is dark, and the projected image interferes with comfortable viewing, which is an obstacle to the production. was there.

  In order to solve the above problems, it has been proposed to use a reflective screen having a surface layer having a specific surface shape on the surface on the image source side (Patent Documents 1 and 2). However, the solutions disclosed in Patent Documents 1 and 2 are limited to the prevention of the reflection of the image light reflected by the surface of the reflection type screen on the ceiling, and prevent the reflection of the transmitted light or the like other than the reflected light. I couldn't do it.

JP, 2013-130837, A JP, 2014-71278, A

  The present invention has been made in view of the above technical problems, and an object thereof is to use an image projection system including an image projection unit, and other than an image projection object by the image light projected from the image projection unit. Another object of the present invention is to provide an optical element which prevents an observer from visually recognizing an unnecessary image on the object.

  In order to solve the above technical problems, the inventors of the present invention have made earnest studies, and as a result, set a specific optical element on an object other than an image projection target, and use the image light projected from the image projection unit as an optical element. It was found that the above technical problems can be solved by not forming an image above. The present invention has been completed based on such findings.

That is, according to one aspect of the present invention,
An optical element used in a video projection system including a video projection unit, the optical element being installed on an object other than a video projection target,
An optical element is provided, on which image light projected from the image projection unit does not form an image.

  In the aspect of the present invention, it is preferable that the optical element includes a circularly polarizing plate.

  In the aspect of the present invention, it is preferable that the optical element further includes a reflection plate.

  In the aspect of the present invention, it is preferable that the circularly polarizing plate includes a linear polarizing plate and a quarter wavelength plate.

  In the aspect of the present invention, it is preferable that the circularly polarizing plate further includes an adhesive layer between the linearly polarizing plate and the quarter wavelength plate.

  In the aspect of the invention, it is preferable that the optical element further includes an adhesive layer between the circularly polarizing plate and the reflecting plate.

According to another aspect of the invention,
An image projection system comprising an image projection unit and the optical element,
An image projection system is provided in which image light projected from the image projection unit does not form an image on the optical element.

  In another aspect of the present invention, it is preferable that the image projection system further includes a transparent screen as an image projection target.

  In another aspect of the present invention, it is preferable that, of the image light projected from the image projection unit, the light transmitted through the transparent screen or the light reflected by the transparent screen does not form an image on the optical element. ..

In another aspect of the present invention, the transparent screen is a reflective transparent screen,
It is preferable that the optical element is installed on an object other than the reflective transparent screen, and image light projected from the image projection unit does not form an image on the optical element.

In another aspect of the present invention, the transparent screen is a transmissive transparent screen,
It is preferable that the optical element is installed on an object other than the transmissive transparent screen, and image light projected from the image projection unit does not form an image on the optical element.

  In another aspect of the present invention, the haze value of the transparent screen is preferably 35% or less.

  In another aspect of the present invention, it is preferable that an antireflection layer is further provided on at least one side of the transparent screen.

  According to the present invention, it is possible to provide an optical element that prevents an observer from visually recognizing an unnecessary image by the image light projected from the image projection unit when using the image projection system including the image projection unit. You can A projection image system equipped with such an optical element does not form an image of the image light projected from the image projection unit on the optical element, and can prevent an observer from visually observing an unnecessary image. Is possible.

It is a conceptual diagram which shows the mechanism which the image light projected from the image projection unit does not form an image on an optical element. 1 is a conceptual diagram showing an embodiment of a projection image system according to the present invention. 1 is a conceptual diagram showing an embodiment of a projection image system according to the present invention. 1 is a conceptual diagram showing an embodiment of a projection image system according to the present invention. It is a conceptual diagram showing the measuring method of the brightness in an example.

<Optical element>
The optical element according to the present invention is used in an image projection system including an image projection unit and is installed on an object other than an image projection object (screen or the like), and image light projected from the image projection unit forms an image. It has a function not to do. Since the image light does not form an image on the optical element, the observer can see an unnecessary image on the object by installing the optical element on an object (wall, ceiling, etc.) where the image light is not desired to be formed. Can be prevented. As a result, a good effect can be achieved. A video projection system using optical elements will be described in detail below.

  The optical element preferably includes a circular polarization plate including a linear polarization plate and a quarter wavelength plate, and further preferably includes a reflection plate. The circularly polarizing plate and the reflection plate may be used as separate and independent members, or may be a laminated body laminated via an adhesive layer.

  Here, a mechanism for preventing image formation when a linear polarizing plate, a quarter-wave plate, and a reflector are used in combination as the optical element of the present invention will be described with reference to FIG. As shown in FIG. 1, the projection light (non-polarized light) projected from the image projection unit is transmitted through the linear polarization plate to be linearly polarized light, and is transmitted through the quarter wavelength plate to be circularly polarized light. Then, the circularly polarized light is reflected by the reflector in a circularly polarized state opposite to the incident light, passes through the quarter-wave plate again, and is a polarization orthogonal to the polarization axis of the linearly polarized light that first passed through the linear polarizing plate. After it becomes a linearly polarized light having an axis, it is absorbed by the linearly polarizing plate and does not pass therethrough, and it does not form an image on the linearly polarizing plate. Therefore, when viewed through the linear polarizing plate, the quarter-wave plate and the reflecting plate, no image is visually recognized on the wall. If the reflection plate is not used, when the image light transmitted through the quarter-wave plate is reflected by the wall, a part of the polarization state of the image light is canceled, the image light is transmitted through the linear polarizing plate, and the light is slightly connected. The image may be visible. In FIG. 1, the linear polarization plate, the quarter-wave plate, and the reflection plate are shown as separate and independent members. However, since light is refracted at each air interface, the linear polarization plate, 1 / The four-wave plate and the reflection plate are preferably used as a laminate. In FIG. 1, only the reflection plate is installed on the wall for the sake of explanation, but it is preferable to install and use the laminated body on the wall.

<Video projection system>
A video projection system according to the present invention comprises a video projection unit and the above-mentioned optical element installed on an object other than a video projection target. By using such a video projection system, the video light projected from the video projection unit does not form an image on the optical element, so that it is possible to prevent an observer from visually recognizing an unnecessary image on the object, Good performance is possible.

  In the video projection system according to the present invention, the video projection unit may include a video video projection target such as a screen, and the video projection unit is the front side (observer side) or the rear side of the video projection target. It may be arranged on either side (on the side opposite to the observer). The screen may be a reflective transparent screen whose rear surface can be seen through or a transmissive transparent screen. By placing the optical element according to the present invention on an object such as a ceiling, a wall, or a floor surface that hinders visual recognition of an image on an image projection object such as a screen, unnecessary imaging on the ceiling, wall, floor surface, or the like. Can be suppressed, and good image production can be achieved.

  2 to 4 are conceptual diagrams of embodiments of the image projection system for explaining the image projection system according to the present invention in more detail.

  In the image projection system shown in FIG. 2, the image projection unit 11 is arranged on the front side (observer 15 side) of the image projection target 12, and the optical element 13 is arranged on the rear side of the image projection target 12 (observation target). And is located on the wall that exists on the opposite side). The image light 14 (solid arrow) projected from the image projection unit 11 forms an image on the image projection object 12 and is visually recognized by an observer, but a part of the image light passes through the image projection object 12. , Reaches the optical element 13 arranged on the wall. Since the image light is absorbed by the optical element 13 (dotted arrow line), the image light is not formed on the optical element 13.

  In the image projection system shown in FIG. 3, the image projection unit 21 is arranged on the front side of the image projection target 22 (observer 25 side), and the optical element 23 is present on the front side of the image projection target 22. It is placed on the wall. The image light 24 (solid arrow) projected from the image projection unit 21 forms an image on the image projection object 22 and is visually recognized by an observer, but a part of the image light is reflected by the image projection object 22. , Reaches the optical element 23 arranged on the wall. Since the image light is absorbed by the optical element 23 (dotted arrow line), the image light is not formed on the optical element 23.

  In the image projection system shown in FIG. 4, the image projection unit 31 is arranged on the front side (observer 35 side) of the image projection target 32, and the optical element 33 is provided on the ceiling above the image projection target 32. It is located in. The image light 34 (solid arrow) projected from the image projection unit 31 forms an image on the image projection object 32 and is visually recognized by an observer, but a part of the image light is reflected by the image projection object 32. , Reaches the optical element 33 arranged on the ceiling. Since the image light is absorbed by the optical element 33 (dotted arrow line), the image light is not formed on the optical element 31.

  Hereinafter, the image projection unit and the image projection object of the image projection system will be described in detail.

<Projection unit>
The projection unit used in the image projection system is not particularly limited as long as it can project an image on the following image projection target, and for example, a commercially available rear projector or front projector can be used.

<Image projection target>
The image projection object used in the image projection system has a projection surface on which the image light projected by the projection unit is formed. Examples of the image projection target include transparent screens for projectors and white screens, and it is preferable to use transparent screens. By installing the above optical element on an object (wall, ceiling, etc.) other than the transparent screen, the projection light does not form an image on the optical element, and the observer can see an unnecessary image on the object. Can be prevented.

<Transparent screen>
The transparent screen used as the image projection object will be described in detail below. The transparent screen preferably includes a light diffusion layer containing a binder and fine particles. The transparent screen may have a single-layer structure composed of only a light diffusion layer, or a laminate having a multi-layer structure further including other layers such as a protective layer, a base material layer, an adhesive layer, and an antireflection layer. It may be. Further, the transparent screen may include a support such as glass or a transparent partition. The transparent screen can achieve both visibility of projected light and visibility of transmitted light by anisotropically diffusing and reflecting the projection light emitted from the light source.

  The transparent screen may be a transmissive screen (rear projection screen) or a reflective screen (front projection screen). That is, in the image projection system including the transparent screen according to the present invention, the position of the projection unit (light source) may be on the front side (observer side) with respect to the screen, or on the rear side (side opposite to the observer). It may be. Further, the transparent screen may be flat or curved.

  The transparent screen may be flat or curved. For example, the transparent screen can be suitably used for a glass window, a head-up display, a wearable display and the like. In addition, in the present invention, the term “transparent” means that the transparency is such that transmissivity and visibility can be realized according to the application, and includes being semitransparent.

  The haze value of the transparent screen is preferably 35% or less, more preferably 1% or more and 30% or less, still more preferably 1.5% or more and 25% or less, and particularly preferably 2% or more and 10% or less. Is. Further, the transparent screen has a total light transmittance of preferably 60% or more and 98% or less, more preferably 65% or more and 96% or less, further preferably 70% or more and 94% or less, and further more It is preferably 75% or more and 92% or less. When the haze value and the total light transmittance of the transparent screen are within the above ranges, the transparency is high and the transmission visibility can be further improved. In the present invention, the haze value and the total light transmittance of the transparent screen are measured using a turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd., product number: NDH-5000) according to JIS-K-7361 and JIS-K-. It can be measured according to 7136.

  The transparent screen has an image clarity of preferably 65% or more, more preferably 70% or more and 98% or less, still more preferably 75% or more and 96% or less, still more preferably 80% or more and 94%. It is below. When the image clarity of the transparent screen is within the above range, the image seen through the transparent screen becomes extremely clear. In the present invention, the image clarity is a value of image clarity (%) when measured with an optical comb width of 0.125 mm according to JIS K7374.

(Light diffusion layer)
The light diffusion layer contains a binder and fine particles. The following light-reflecting fine particles can be preferably used as the fine particles. By using such fine particles, light can be anisotropically diffused and reflected in the light diffusion layer, and the light utilization efficiency can be improved.

  The thickness of the light diffusion layer is not particularly limited, but is preferably 0.1 μm to 20 mm, more preferably 0.2 μm to 15 mm, from the viewpoints of use, productivity, handleability, and transportability. And more preferably 1 μm to 10 mm. When the thickness of the light diffusion layer is within the above range, it is easy to maintain the strength of the screen. The light diffusion layer may be a molded body obtained by using the following organic binder or inorganic binder, or may be a coating film formed on a substrate made of glass, resin or the like. The light diffusing layer may have a single-layer structure, or may have a multi-layer structure in which two or more types of layers are laminated by coating or the like, or two or more types of light diffusing layers are bonded with an adhesive or the like.

  For the light diffusion layer, it is preferable to use a highly transparent binder in order to obtain a highly transparent film. The binder may be an organic binder or an inorganic binder, and the organic binder may be a thermoplastic resin, or a self-crosslinking resin such as a thermosetting resin and an ionizing radiation curable resin. Resin, acrylic urethane resin, polyester acrylate resin, polyurethane acrylate resin, epoxy acrylate resin, polyester resin, polyolefin resin, urethane resin, epoxy resin, polycarbonate resin, cellulose resin, acetal resin, Examples thereof include vinyl resins, polystyrene resins, polyamide resins, polyimide resins, melamine resins, phenol resins, silicone resins, and fluorine resins.

  Examples of the thermoplastic resin include acrylic resin, polyester resin, polyolefin resin, cellulose resin, vinyl resin, polycarbonate resin, and polystyrene resin. Among these, it is more preferable to use polymethyl methacrylate resin, polyethylene terephthalate resin, polyethylene naphthalate resin, polypropylene resin, cycloolefin polymer resin, cellulose acetate propionate resin, polyvinyl butyral resin, polycarbonate resin, and polystyrene resin. .. These resins may be used alone or in combination of two or more.

  Examples of the ionizing radiation curable resin include acrylic resin, urethane resin, acrylic urethane resin, epoxy resin, and silicone resin. Among these, those having an acrylate-based functional group, for example, relatively low molecular weight polyester resin, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, spiro acetal resin, polybutadiene resin, polythiol polyene resin, many Oligomers or prepolymers of polyfunctional compounds such as polyhydric alcohols such as (meth) allylate, and monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone as a reactive diluent. And polyfunctional monomers such as polymethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) actuate. It is preferable to contain a relatively large amount of rate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate and the like. .. Further, the ionizing radiation curable resin may be a mixture of a thermoplastic resin and a solvent.

  Examples of the thermosetting resin include phenol resin, epoxy resin, silicone resin, melamine resin, urethane resin, urea resin and the like. Of these, epoxy resins and silicone resins are preferable.

Examples of the highly transparent inorganic binder include water glass, a glass material having a low softening point, and a sol-gel material. Water glass is a concentrated aqueous solution of alkali silicate, and sodium is usually contained as an alkali metal. A typical water glass can be represented by Na ₂ O · nSiO ₂ (n: any positive number), and as a commercial product, sodium silicate manufactured by Fuji Chemical Co., Ltd. can be used.

The glass material having a low softening point is a glass having a softening temperature of preferably 150 to 620 ° C, more preferably a softening temperature of 200 to 600 ° C, and most preferably a softening temperature of 250 to 550. It is in the range of ° C. As such a glass material, _PbO-B 2 _{O 3 system, PbO-B 2 O 3 -SiO} 2 _{system, PbO-ZnO-B 2 O} 3 system, heat treating the mixture containing the acid component and a metal chloride Examples of the lead-free low softening point glass obtained by The low softening point glass material may be mixed with a solvent, a high boiling point organic solvent or the like in order to improve the dispersibility of fine particles and the moldability.

  A sol-gel material is a group of compounds that undergo hydrolysis and polycondensation due to the action of heat, light, a catalyst, etc., and are cured. For example, it is a metal alkoxide (metal alcoholate), a metal chelate compound, a metal halide, a liquid glass, a spin-on glass, or a reaction product of these, and may contain a catalyst that accelerates curing. Further, a part of the metal alkoxide functional group may have a photoreactive functional group such as an acrylic group. These may be used alone or in combination of a plurality of types depending on the required physical properties. The cured product of the sol-gel material refers to a state in which the polymerization reaction of the sol-gel material has sufficiently progressed. The sol-gel material chemically bonds with the surface of the inorganic substrate during the polymerization reaction and strongly adheres thereto. Therefore, a stable cured product layer can be formed by using a cured product of a sol-gel material as the cured product layer.

  The metal alkoxide is a group of compounds obtained by reacting any metal species with a hydrolysis catalyst or the like with water or an organic solvent, and any metal species, and a hydroxy group, a methoxy group, an ethoxy group, a propyl group, isopropyl group. It is a group of compounds in which functional groups such as groups are bonded. Examples of the metal species of the metal alkoxide include silicon, titanium, aluminum, germanium, boron, zirconium, tungsten, sodium, potassium, lithium, magnesium and tin.

  For example, as the metal alkoxide whose metal species is silicon, dimethyldiethoxysilane, diphenyldiethoxysilane, phenyltriethoxysilane, methyltriethoxysilane (MTES), vinyltriethoxysilane, p-styryltriethoxysilane, and methylphenyldiethoxysilane. Ethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3 -Methacryloxypropyltriethoxysilane, 3-acryloxypropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldiethoxysilane, N-2- (aminoethyl) -3-aminopro Rutriethoxysilane, 3-aminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropyltriethoxysilane, triethoxysilane, diphenylsilanediol, dimethylsilanediol, etc. Examples include compounds in which the ethoxy group of these compounds is replaced with a methoxy group, a propyl group, an isopropyl group, a hydroxy group, and the like. Among these, triethoxysilane (TEOS) and tetramethoxysilane (TMOS) obtained by replacing the ethoxy group of TEOS with a methoxy group are particularly preferable. These may be used alone or in combination of a plurality of types.

(solvent)
These organic binders and inorganic binders may further contain a solvent if necessary. The solvent is not limited to an organic solvent, and a solvent used in a general coating composition can be used. For example, hydrophilic solvents such as water can be used. When the binder of the present invention is a liquid, it need not contain a solvent.

  Specific examples of the solvent according to the present invention include alcohols such as methanol, ethanol, isopropyl alcohol (IPA), n-propanol, butanol, 2-butanol, ethylene glycol, and propylene glycol, hexane, heptane, octane, decane, Aliphatic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, and tetramethylbenzene, ethers such as diethyl ether, tetrahydrofuran, dioxane, acetone, methyl ethyl ketone, isophorone, cyclohexanone, cyclopentanone , N-methyl-2-pyrrolidone and other ketones, butoxyethyl ether, hexyloxyethyl alcohol, methoxy-2-propanol, benzyloxyethanol and other ether ethers. Coals, glycols such as ethylene glycol and propylene glycol, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, cellosolve, methyl cellosolve, ethyl cellosolve, carbitol, methyl carbitol, ethyl carbitol, butyl carbitol, propylene. Glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monomethyl ether, glycol ethers such as triethylene glycol monoethyl ether, ethyl acetate, butyl acetate, ethyl lactate, Esters such as γ-butyrolactone, phenol , Phenols such as chlorophenol, amides such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone, halogen-based solvents such as chloroform, methylene chloride, tetrachloroethane, monochlorobenzene and dichlorobenzene, Examples thereof include a hetero element-containing compound such as carbon disulfide, water, and a mixed solvent thereof. The amount of the solvent added can be appropriately adjusted according to the types of the binder and the fine particles, the viscosity range suitable for the manufacturing process described below, and the like.

(Light reflective fine particles)
The light-reflecting fine particles may have any shape, may have a substantially spherical shape, and may have a flaky shape. When the shape of the light-reflecting fine particles is substantially spherical, the median diameter of the primary particles is preferably 0.1 to 2500 nm, more preferably 0.2 to 1500 nm, and further preferably 0.5 to 500 nm. .. When the median diameter of the primary particles of the light-reflecting fine particles is within the above range, a sufficient diffusion effect of the projection light can be obtained without impairing the transmission visibility, and a clear image can be projected on the transparent screen. .. In the present invention, the median diameter (D ₅₀ ) of the primary particles of the light-reflecting fine particles is measured by a dynamic light scattering method using a particle size distribution analyzer (Otsuka Electronics Co., Ltd., trade name: DLS-8000). It can be determined from the measured particle size distribution.

  When the shape of the light-reflecting fine particles is flaky, the average diameter of the primary particles is preferably 0.01 to 100 μm, more preferably 0.05 to 80 μm, further preferably 0.1 to 50 μm, and even more preferably 0. 0.5 to 30 μm. Furthermore, the light-reflecting fine particles have an average aspect ratio (= average diameter / average thickness of the light-reflecting fine particles) of preferably 3 to 800, more preferably 4 to 700, still more preferably 5 to 600, and even more preferably still more preferably. It is 10 to 500. When the average diameter and the average aspect ratio of the light-reflecting fine particles are within the above ranges, a sufficient scattering effect of the projection light can be obtained without impairing the transmission visibility, so that a clear image can be projected on the transparent screen. it can. In the present invention, the average diameter of the light-reflecting fine particles was measured using a laser diffraction particle size distribution measuring device (manufactured by Shimadzu Corporation, product number: SALD-2300). The average aspect ratio was calculated from an SEM (manufactured by Hitachi High-Technologies Corporation, trade name: SU-1500) image.

As the flaky light-reflecting fine particles, a glitter material that can be processed into flakes can be preferably used. The regular reflectance of the light-reflecting fine particles is preferably 12.0% or more, more preferably 15.0% or more, and further preferably 20.0% or more and 80.0% or less. In the present invention, the regular reflectance of the light-reflecting fine particles is a value measured as follows. By measuring the regular reflectance, it is possible to grasp the reflection performance of the light-reflecting fine particles in consideration of the oxidation state and the like.
(Regular reflectance)
A spectrophotometer (manufactured by Konica Minolta Co., Ltd., product number: CM-3500d) was used to measure light-reflecting fine particles dispersed in an appropriate solvent (water or methyl ethyl ketone) on a slide glass to a thickness of 0.5 mm. The coated glass plate was coated and dried as described above, and the specular reflectance of the obtained coated glass plate when light was incident on the coated film portion from the glass surface at an angle of 45 degrees with respect to the normal to the glass surface. Was measured.

  As the light-reflecting fine particles, depending on the kind of the binder to be dispersed, for example, aluminum, silver, copper, platinum, gold, titanium, nickel, tin, tin-cobalt alloy, indium, chromium, titanium oxide, aluminum oxide, Metallic particles made of diamond and zinc sulfide, a glittering material obtained by coating a resin or glass with a metal or a metal oxide, or a glittering material obtained by coating natural mica or synthetic mica with a metal oxide can be used. As the light-reflecting fine particles, commercially available products may be used, and for example, aluminum powder manufactured by Daiwa Metal Powder Co., Ltd. can be preferably used.

  The content of the light-reflecting fine particles in the light-diffusing layer can be appropriately adjusted according to the shape of the light-reflecting fine particles and the regular reflectance. For example, the content of the light-reflecting fine particles is preferably 0.0001 to 5.0 mass% with respect to the binder, preferably 0.0005 to 3.0 mass%, and more preferably 0.001. Is 2.0% by mass. Visualization of projection light by anisotropically diffusing and reflecting the projection light emitted from the light source by forming light diffusion layers by dispersing light-reflecting fine particles in a binder at a low concentration within the above range And the visibility of transmitted light can be improved.

  In addition to the fine particles, conventionally known additives may be added to the light diffusion layer depending on the application. Examples of the additive include an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a release agent, a flame retardant, a plasticizer, a lubricant, and a coloring material. As the coloring material, carbon black, azo dyes, anthraquinone dyes, perinone dyes and the like can be used. Further, a liquid crystal compound or the like may be mixed.

(Base material layer)
The base material layer is a layer for supporting the above-mentioned light diffusion layer and can improve the strength of the transparent screen. The base material layer is preferably formed using a highly transparent material such as glass or resin that does not impair the transmission visibility of the transparent screen or desired optical characteristics. As such a resin, for example, a resin having high transparency similar to that of the above light diffusion layer can be used. Moreover, you may use the composite film or sheet which laminated | stacked 2 or more types of said resin. The thickness of the base material layer can be appropriately changed depending on the material so that the strength thereof is appropriate, and may be, for example, in the range of 10 to 1000 μm.

(Protective layer)
The protective layer is laminated on the surface side (observer side) of the transparent screen and is a layer for imparting functions such as light resistance, scratch resistance, and antifouling property. The protective layer is preferably formed using a resin that does not impair the transmission visibility of the transparent screen or desired optical characteristics. As such a resin, for example, a resin curable by ultraviolet rays or electron beams, that is, an ionizing radiation curable resin, a mixture of an ionizing radiation curable resin with a thermoplastic resin and a solvent, and a thermosetting resin should be used. However, among these, ionizing radiation curable resins are particularly preferable.

  The film forming component of the ionizing radiation curable resin composition preferably has an acrylate-based functional group, for example, a relatively low molecular weight polyester resin, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, Spiroacetal resins, polybutadiene resins, polythiol polyene resins, polyfunctional compounds such as polyhydric alcohols (meth) acrylate oligomers or prepolymers and ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene as a reactive diluent, Monofunctional and polyfunctional monomers such as methylstyrene and N-vinylpyrrolidone, for example, polymethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acryle. , Diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, etc. Those containing a large amount can be used.

  In order to make the above ionizing radiation curable resin composition into an ultraviolet curable resin composition, acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime ester, tetramethylthiuram mono are used as photopolymerization initiators therein. Sulfides, thioxanthones, and n-butylamine, triethylamine, poly-n-butylphosphine, and the like as photosensitizers can be mixed and used. Particularly in the present invention, it is preferable to mix urethane acrylate as an oligomer and dipentaerythritol hexa (meth) acrylate as a monomer.

  As a method for curing the ionizing radiation curable resin composition, the method for curing the ionizing radiation curable resin composition may be a usual curing method, that is, an electron beam or an ultraviolet ray may be applied. For example, in the case of electron beam curing, 50 to 50 emitted from various electron beam accelerators such as Cockloft-Walton type, Van de Graaff type, resonance transformer type, insulating core transformer type, linear type, dynamitron type and high frequency type. An electron beam or the like having an energy of 1000 KeV, preferably 100 to 300 KeV is used. In the case of ultraviolet curing, ultraviolet rays emitted from light rays such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc and a metal halide lamp are used. Available.

  The protective layer is formed by spin coating, die coating, dip coating, bar coating, flow coating, roll coating, gravure coating or the like on the above light diffusing layer with the coating liquid of the above ionizing radiation (ultraviolet) ray curable resin composition. Then, it can be formed by coating on the surface of the light diffusion layer and curing the coating liquid by the above means. In addition, the surface of the protective layer may be provided with a fine structure such as a concavo-convex structure, a prism structure, or a microlens structure depending on the purpose.

(Adhesive layer)
The adhesive layer is a layer for attaching the film to the transparent screen. The pressure-sensitive adhesive layer is preferably formed using a pressure-sensitive adhesive composition that does not impair the transmission visibility of the transparent screen or desired optical characteristics. Examples of the adhesive composition include natural rubber-based, synthetic rubber-based, acrylic resin-based, polyvinyl ether resin-based, urethane resin-based, silicone resin-based and the like. Specific examples of synthetic rubber include styrene-butadiene rubber, acrylonitrile-butadiene rubber, polyisobutylene rubber, isobutylene-isoprene rubber, styrene-isoprene block copolymer, styrene-butadiene block copolymer, styrene-ethylene-butylene block. A copolymer is mentioned. Specific examples of the silicone resin type include dimethyl polysiloxane and the like. These adhesives can be used alone or in combination of two or more. Among these, acrylic adhesives are preferable.

  The acrylic resin pressure-sensitive adhesive contains at least a (meth) acrylic acid alkyl ester monomer and is polymerized. It is generally a copolymer of a (meth) acrylic acid alkyl ester monomer having an alkyl group having about 1 to 18 carbon atoms and a monomer having a carboxyl group. In addition, (meth) acrylic acid means acrylic acid and / or methacrylic acid. Examples of (meth) acrylic acid alkyl ester monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, sec-propyl (meth) acrylate, and (meth) acrylic acid. n-butyl, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylic acid Examples thereof include n-octyl, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, undecyl (meth) acrylate, and lauryl (meth) acrylate. The (meth) acrylic acid alkyl ester is usually copolymerized in the acrylic pressure-sensitive adhesive at a ratio of 30 to 99.5 parts by mass.

  Further, as the monomer having a carboxyl group forming the acrylic resin adhesive, a monomer containing a carboxyl group such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, monobutyl maleate and β-carboxyethyl acrylate. Can be mentioned.

  In addition to the above, the acrylic resin pressure-sensitive adhesive may be copolymerized with a monomer having another functional group within a range not impairing the properties of the acrylic resin pressure-sensitive adhesive. Examples of monomers having other functional groups include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and monomers containing a hydroxyl group such as allyl alcohol; (meth) acrylamide, N-methyl. Monomers containing amide groups such as (meth) acrylamide and N-ethyl (meth) acrylamide; monomers containing amide groups and methylol groups such as N-methylol (meth) acrylamide and dimethylol (meth) acrylamide; aminomethyl ( Monomers having functional groups such as amino group-containing monomers such as (meth) acrylate, dimethylaminoethyl (meth) acrylate, and vinylpyridine; epoxy group-containing mono such as allyl glycidyl ether and (meth) acrylic acid glycidyl ether Chromatography and the like. In addition to these, fluorine-substituted (meth) acrylic acid alkyl esters, (meth) acrylonitrile, and the like, vinyl group-containing aromatic compounds such as styrene and methylstyrene, vinyl acetate, vinyl halide compounds, and the like can be given.

  The adhesive may be a commercially available one, for example, SK Dyne 2094, SK Dyne 2147, SK Dyne 1811L, SK Dyne 1442, SK Dyne 1435, and SK Dyne 1415 (above, manufactured by Soken Kagaku Co., Ltd.), Olivine EG-655, Olivine BPS5896 (above, manufactured by Toyo Ink Co., Ltd.), etc. (above, trade name) can be preferably used.

(Antireflection layer)
The antireflection layer is a layer for preventing reflection on the outermost surface of the transparent screen and reflection from external light. The antireflection layer may be laminated on at least one side of the transparent screen, preferably on the front side (observer side), or may be laminated on both sides. Especially when it is used as a transparent screen, it is preferably laminated on the viewer side. The antireflection layer is preferably formed using a resin that does not impair the transmission visibility of the transparent screen or desired optical characteristics. As such a resin, for example, a resin curable by ultraviolet rays or electron beams, that is, an ionizing radiation curable resin, a mixture of an ionizing radiation curable resin with a thermoplastic resin and a solvent, and a thermosetting resin should be used. However, among these, ionizing radiation curable resins are particularly preferable. Further, the surface of the antireflection layer may be provided with a fine structure such as a concavo-convex structure, a prism structure, and a microlens structure depending on the purpose.

  The method for forming the antireflection layer is not particularly limited, but includes a method of applying a coating film, a method of dry coating directly on the film substrate by vapor deposition or sputtering, gravure coating, micro gravure coating, bar coating, slide die coating. Methods such as coating, slot die coating, and wet coating such as dip coating can be used.

(Functional layer)
The transparent screen according to the present invention may include various conventionally known functional layers in addition to the layers described above. Examples of the functional layer include a light absorbing layer containing a dye or a colorant, a prism sheet, a microlens sheet, a Fresnel lens sheet, a light diffusing layer such as a lenticular lens sheet, and a light ray cutting layer such as ultraviolet rays and infrared rays. Be done.

(Method for manufacturing transparent screen)
The method for manufacturing a transparent screen includes a step of forming a light diffusion layer. The step of forming the light diffusion layer consists of a kneading step and a film forming step, an extrusion molding method, a cast film forming method, gravure coating, micro gravure coating, bar coating, slide die coating, slot die coating. Can be molded by known methods such as coating method including dip coating, spraying method, injection molding method, calender molding method, blow molding method, compression molding method, cell casting method, extrusion molding method, injection molding method, coating method. Can be preferably used.

  The method for producing a transparent screen may include a step of further laminating a base material layer, a protective layer, an adhesive layer and the like on the resin film (light diffusion layer) obtained in the film forming step. The method for laminating each layer is not particularly limited and may be a conventionally known method. When laminating each layer by dry lamination, an adhesive or the like may be used within a range that does not impair the transmission visibility of the transparent screen and desired optical characteristics.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

In the examples and comparative examples, the methods for measuring each physical property and performance are as follows.
(1) Haze Using a turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd., product number: NDH-5000), the haze was measured according to JIS K7136.
(2) Total light transmittance The total light transmittance of the transparent light scatterer was measured using a turbidimeter (manufactured by Nippon Denshoku Industries Co., Ltd., product number: NDH-5000) according to JIS K7361-1. .
(3) Image clarity Image clarity (% when measured with an optical comb width of 0.125 mm according to JIS K7374, using an image clarity measuring device (manufactured by Suga Test Instruments Co., Ltd., product number: ICM-1T). ) Was defined as the image clarity. The larger the value of the image clarity, the higher the image clarity and the clearer the image seen through the transparent screen.
(4) Luminance on the front wall The luminance on the front wall was measured as follows. That is, a transparent screen was installed in a dark room, and a projector (QTMI Q6 manufactured by AddTron Technology Co., Ltd.) was installed as a video projection unit on the front side 30 cm away from the normal direction of the transparent screen. Further, a white plate was installed on the front side 90 cm away from the transparent screen in the normal direction. Subsequently, a two-dimensional color luminance meter (manufactured by Konica Minolta Co., Ltd., model number: CA-2000) was installed at an angle of 45 degrees to the projector side 35 cm away from the front side white plate in the normal direction, and the projector was transparent The brightness of the white plate when a white plain image was projected on the screen was measured (see FIG. 5).
(5) Luminance on the rear wall The luminance on the rear wall was measured as follows. That is, in a dark room, a transparent screen and an image projection unit are installed in the same manner as when measuring the brightness on the front wall, and the rear side is 90 cm away from the normal direction of the transparent screen (on the side opposite to the projector with the transparent screen in between). A white plate was installed. Subsequently, a two-dimensional color luminance meter was installed at a tilt of 45 degrees on the transparent screen side 35 cm away from the normal line of the white plate, and the brightness of the white plate when a white plain image was projected on the transparent screen by the projector was measured. (See FIG. 5).
(6) Luminance on the ceiling Luminance on the ceiling was measured as follows. That is, in a dark room, a transparent screen, a video projection unit, a white plate and a two-dimensional color luminance meter were installed as in the case of measuring the brightness on the front wall, and a white plate was further installed on the upper ceiling of the white plate. Subsequently, a white plain image was projected on a transparent screen with a projector, and the brightness of a white plate installed on the ceiling was measured by a two-dimensional color brightness meter.

[Example 1]
First, a linear polarization plate (polarization degree 99.82%, single transmittance: 40%, manufactured by Pola-Techno Co., Ltd., trade name: SHC-125U, with an adhesive layer) is tilted at an optical axis of 45 degrees to a quarter wavelength. Plates (manufactured by Teijin Kasei Co., Ltd., trade name: Pure Ace RM) were attached to obtain a laminate. On the 1/4 wavelength plate side of this laminate, a reflector (Toray Industries, Inc., Metalmy TS50) was further laminated via an optical adhesive film (Panac Co., Ltd., trade name PD-S1), An optical element was obtained.

  Next, polyethylene terephthalate (PET) pellets (manufactured by Bell Polyester Co., Ltd., brand IFG8L) and 0.012 mass% of flaky aluminum fine particles A (light-reflecting fine particles, average diameter of primary particles: 1 μm) based on the PET pellets. , Aspect ratio 300, regular reflectance 62.8%) were mixed in a tumbler mixer for 30 minutes to obtain PET pellets on the surface of which aluminum flakes were uniformly adhered. The obtained pellets were fed to a hopper of a twin-screw kneading extruder equipped with a strand die to obtain a masterbatch in which flaky aluminum was kneaded at an extrusion temperature of 250 ° C. After uniformly mixing the obtained masterbatch and PET pellets (brand IFG8L) in a ratio of 1: 2, the mixture was put into a hopper of a single-screw extruder equipped with a T die and extruded at 250 ° C. to obtain a thickness of 75 μm. The film was formed. The obtained film was attached to a transparent glass plate having a thickness of 2 mm using an adhesive film (Panac Co., Ltd., Panaclean PD-S1 thickness 25 μm) to obtain a haze of 2.7% and a total light transmittance of 89. A transparent screen of 0.1% and image clarity 91% was obtained.

After installing the transparent screen obtained above in a room with a wall and a ceiling, a video projection unit (AddTron Technology Co., Ltd., QUMI Q6) was installed on the front side (observer side) of the transparent screen, and it was transparent. The optical element obtained above was installed on the wall on the rear side (the side opposite to the observer) of the screen to fabricate a video projection system (the embodiment of FIG. 2). Then, the image light was projected from the image projection unit toward the transparent screen. Whether or not an observer can visually recognize an unnecessary image on the wall on which the optical element is installed by the light transmitted through the transparent screen was visually evaluated according to the following criteria. In addition, the brightness on the rear wall when the optical element was not installed was 72.7 cd / cm ² (Comparative Example 1), and the brightness on the rear wall when the optical element was installed was 1.0 cd / cm ^2. It was cm ² , and it was confirmed that the transmitted light was largely absorbed.

[Example 2]
A video projection system was produced in the same manner as in Example 1 except that the optical element was installed on the front wall of the transparent screen (the embodiment of FIG. 3). Then, as in Example 1, the image light was projected from the image projection unit toward the transparent screen. Whether or not an observer can visually recognize an unnecessary image on the wall on which the optical element is installed by the light reflected by the transparent screen was visually evaluated according to the following criteria. The brightness on the front wall when no optical element was installed was 8.5 cd / cm ² (Comparative Example 3), and the brightness on the front wall when the optical element was installed was 0.4 cd / cm ^2. It was cm ² , and it was confirmed that the reflected light was significantly absorbed.

[Example 3]
A video projection system was produced in the same manner as in Example 1 except that the optical element was installed on the ceiling (the embodiment of FIG. 4). Then, as in Example 1, the image light was projected from the image projection unit toward the transparent screen. Whether or not an observer can visually recognize an unnecessary image on the ceiling where an optical element is reflected by the light reflected by the transparent screen was visually evaluated according to the following criteria. The brightness on the ceiling without the optical element was 10.8 cd / cm ² (Comparative Example 4), and the brightness on the ceiling with the optical element was 0.5 cd / cm ² , It was confirmed that the light was largely absorbed.

[Example 4]
An optical element was obtained in the same manner as in Example 1 except that the reflection plate was not laminated. Next, in the same manner as in Example 1, a video projection system was produced. Then, as in Example 1, the image light was projected from the image projection unit toward the transparent screen. Whether or not an observer can visually recognize an unnecessary image on the rear wall on which the optical element is installed by light transmitted through the transparent screen was visually evaluated according to the following criteria. In addition, the brightness on the rear wall when the optical element is not installed is 72.7 cd / cm ² (Comparative Example 1), and the brightness on the rear wall when the optical element is installed is 13.7 cd / cm ^2. It was cm ² , and it was confirmed that the transmitted light was absorbed.

[Example 5]
The optical element manufactured in Example 1 was installed on the wall of a room having a wall and a ceiling, and the image projection unit used in Example 1 directly projected the image light toward the wall on which the optical element was installed. Whether or not an undesired image on the wall on which the optical element is installed by the image light can be visually recognized was visually evaluated according to the following criteria. The brightness on the wall without the optical element was 84.0 cd / cm ² (Comparative Example 2), and the brightness on the wall with the optical element was 1.2 cd / cm ² , which was a direct white solid color. It was confirmed that the projection light was absorbed even though the image was projected.

[Example 6]
The optical element manufactured in Example 4 was installed on the wall of a room having a wall and a ceiling, and the image projection unit used in Example 1 directly projected the image light toward the wall on which the optical element was installed. Whether or not an undesired image on the wall on which the optical element is installed by the image light can be visually recognized was visually evaluated according to the following criteria. In addition, the brightness in the wall without the optical element installed was 84.0 cd / cm ² (Comparative Example 2), and the brightness in the wall with the optical element installed was 16.3 cd / cm ² , which was a direct white solid color. It was confirmed that the projection light was absorbed even though the image was projected.

[Comparative Example 1]
An image projection system was produced in the same manner as in Example 1 except that no optical element was installed. Then, as in Example 1, the image light was projected from the image projection unit toward the transparent screen. Whether or not an undesired image on the rear wall due to the light transmitted through the transparent screen can be visually recognized by the observer was visually evaluated according to the following criteria. The brightness on the rear wall was 72.7 cd / cm ² .

[Comparative example 2]
Image light was projected from the image projection unit used in Example 1 toward a wall on which no optical element was installed, in the same manner as in Example 5 except that no optical element was installed. Whether or not an observer can visually recognize an unnecessary image on the wall on which no optical element is installed by the image light was visually evaluated based on the following criteria. The brightness on the wall where no optical element was installed was 84.0 cd / cm ² .

[Comparative Example 3]
An image projection system was produced in the same manner as in Example 2 except that no optical element was installed. Subsequently, as in Example 2, the image light was projected from the image projection unit toward the transparent screen. Whether or not an undesired image on the front wall due to the light reflected by the transparent screen can be visually recognized by the observer was visually evaluated according to the following criteria. The brightness on the front wall was 8.5 cd / cm ² .

[Comparative Example 4]
An image projection system was produced in the same manner as in Example 3 except that no optical element was installed. Then, as in Example 3, the image light was projected from the image projection unit toward the transparent screen. Whether or not an observer can visually recognize an unnecessary image of the ceiling due to the light reflected by the transparent screen was visually evaluated according to the following criteria. The brightness on the ceiling was 10.8 cd / cm ² .

[Evaluation criteria]
◯: The observer could not visually recognize an unnecessary image on the object (ceiling, wall, etc.) on which the optical element was installed.
Δ: An observer could slightly see an unnecessary image on an object (ceiling, wall, etc.) on which the optical element was installed, but the image was faint.
X: The observer could visually recognize an unnecessary image on the object (ceiling, wall, etc.) on which the optical element was not installed.

The evaluation results are shown in Table 1.

11, 21, 31 Image projection unit 12, 22, 32 Image projected object 13, 23, 33 Optical element 14, 24, 34 Image light 15, 25, 35 Observer

Claims (9)

A video projection system, comprising: a video projection unit, a transparent screen as a video projection target, and an optical element installed on an object other than the video projection target,
The optical element includes a circularly polarizing plate,
Image light projected from the image projection unit forms an image on the transparent screen,
A video projection system in which, of the video light projected from the video projection unit, the light transmitted through the transparent screen or the light reflected by the transparent screen does not form an image on the optical element.   The image projection system according to claim 1, wherein the transparent screen is a reflective transparent screen.   The image projection system according to claim 1, wherein the transparent screen is a transmissive transparent screen.   The image projection system according to claim 1, wherein the haze value of the transparent screen is 35% or less.   The image projection system according to claim 1, further comprising an antireflection layer on at least one side of the transparent screen. It said optical element further comprises a reflector, a video projection system according to any one of claims 1 to 5. The circular polarizing plate composed of a linear polarizing plate and a quarter-wave plate, the image projection system according to any one of claims 1 to 6. The image projection system of claim 7 , wherein the circularly polarizing plate further comprises an adhesive layer between the linearly polarizing plate and the quarter wave plate. The image projection system according to claim 6 , wherein the optical element further comprises an adhesive layer between the circularly polarizing plate and the reflecting plate.