JP2017198951A - Optical element and image projection system having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element which, when used for an image projection system with an image projection unit, prevents viewers from recognizing unnecessary images formed on objects other than an image projection target by image light projected by the image projection unit.SOLUTION: Provided herein is an optical element which is used for an image projection system with an image projection unit by being installed on objects other than an image projection target in order to prevent image light projected by the image projection unit from forming images thereon. Also provided is the image projection system equipped with the image projection unit and the optical element installed on the objects other than the image projection target.SELECTED DRAWING: Figure 1

Description

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

  Conventionally, when projecting an image, it is common for an image projection unit to project image light onto an image projection object such as a screen, and an observer observes the image. In recent years, there has been a growing demand to project and display product information and advertisements on a show window such as a department store or a transparent partition of an event space using a video projection system including such a video projection unit and a video projection object. Yes. However, there is a problem 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 back wall, and the image is reflected. . Such a reflection of the image on the ceiling is a problem that the brightness is conspicuous when the room is dark, and the projected image interferes with comfortable viewing, which disturbs 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 described in Patent Documents 1 and 2 are only for preventing the reflection of the image light reflected by the surface of the reflective screen on the ceiling, and preventing the reflection of reflected light such as transmitted 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-described technical problems, and an object thereof is other than a video projection target using video light projected from a video projection unit when a video projection system including a video projection unit is used. It is an object to provide an optical element that prevents an observer from visually recognizing an unnecessary image on the object.

  As a result of intensive investigations to solve the above technical problem, the inventors of the present invention installed a specific optical element on an object other than the image projection object, and received the image light projected from the image projection unit as an optical element. It has been found that the above technical problem 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 and installed on an object other than a video projection object,
An optical element is provided in which the image light projected from the image projection unit does not form an image.

  In the aspect of this invention, it is preferable that the said optical element is equipped with a circularly-polarizing plate.

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

  In the aspect of the present invention, the circularly polarizing plate is preferably composed of a linearly polarizing plate and a quarter wave 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 ¼ wavelength plate.

  In the aspect of the present 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,
A video projection system comprising a video projection unit and the optical element,
An image projection system is provided in which the 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 video projection system further includes a transparent screen as a video projection target.

  In another aspect of the present invention, it is preferable that the light transmitted through the transparent screen or the light reflected by the transparent screen out of the 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 reflective transparent screen,
Preferably, the optical element is installed on an object other than the reflective transparent screen, and the 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,
Preferably, the optical element is installed on an object other than the transmissive transparent screen, and the 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 preferably has a haze value of 35% or less.

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

  According to the present invention, there is provided an optical element that prevents an observer from visually recognizing an unnecessary image due to video light projected from a video projection unit when a video projection system including a video projection unit is used. Can do. The projection video system provided with such an optical element can prevent the image light projected from the video projection unit from being imaged on the optical element and prevent an observer from visually recognizing an unnecessary image. Is possible.

It is a conceptual diagram which shows the mechanism in which the image light projected from the image projection unit does not image-form on an optical element. It is the conceptual diagram which showed one Embodiment of the projection video system by this invention. It is the conceptual diagram which showed one Embodiment of the projection video system by this invention. It is the conceptual diagram which showed one Embodiment of the projection video system by this invention. It is the conceptual diagram which showed the measuring method of the brightness | luminance in an Example.

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

  The optical element preferably includes a circularly polarizing plate including a linearly polarizing plate and a quarter wavelength plate, and further preferably includes a reflecting plate. The circularly polarizing plate and the reflecting plate may be used as separate and independent members, or may be a laminate that is laminated via an adhesive layer.

  Here, a mechanism for preventing image formation when a linearly polarizing plate, a quarter-wave plate, and a reflecting plate 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 video projection unit passes through the linear polarizing plate to become linearly polarized light, and passes through the quarter wavelength plate to become circularly polarized light. Subsequently, the circularly polarized light is reflected by the reflecting plate in a circularly polarized state opposite to the incident light, is transmitted through the quarter wavelength plate again, and is orthogonally polarized with the polarization axis of the linearly polarized light that is first transmitted through the linear polarizing plate. After it becomes linearly polarized light having an axis, it is absorbed by the linearly polarizing plate and does not pass through, and no image is formed on the linearly polarizing plate. For this reason, when it observes through a linearly-polarizing plate, a quarter wavelength plate, and a reflecting plate, image formation is not visually recognized on a wall. If no reflection plate is used, when the image light transmitted through the quarter-wave plate is reflected by the wall, the polarization state of part of the image light is canceled and transmitted through the linear polarizing plate, fading. The image may be visible. In FIG. 1, the linearly polarizing plate, the quarter-wave plate, and the reflecting plate are shown as separate and independent members. However, since light refraction occurs at each air interface, the linearly polarizing plate, The four-wave plate and the reflecting plate are preferably used as a laminate. In FIG. 1, for the sake of explanation, only the reflector is installed on the wall, but it is preferable to install and use the laminate on the wall.

<Video projection system>
A video projection system according to the present invention includes a video projection unit and the above-described optical element installed on an object other than a video projection object. By using such a video projection system, since the video light projected from the video projection unit does not form an image on the optical element, it is possible to prevent an observer from visually recognizing an unnecessary image on the object, Good production 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 may be a front side (observer side) or a rear side of the video projection target. It may be arranged on either (the side opposite to the observer). The screen may be a reflective transparent screen whose back surface can be seen through, or a transmissive transparent screen. By installing the optical element according to the present invention on an object such as a ceiling, wall, floor, etc. that interferes with visual recognition on a projected object such as a screen, unnecessary image formation on the ceiling, wall, floor, etc. Can be suppressed, and a good video effect can be achieved.

  In order to describe the video projection system according to the present invention in more detail, conceptual diagrams of embodiments of the video projection system are shown in FIGS.

  In the video projection system shown in FIG. 2, the video projection unit 11 is disposed on the front side (observer 15 side) of the video projected body 12, and the optical element 13 is located on the rear side (observer) of the video projected body 12. On the opposite wall). The image light 14 (solid arrow line) projected from the image projection unit 11 forms an image on the image projection target 12 and is visually recognized by the observer, but a part of the image light is transmitted through the image projection target 12. To the optical element 13 arranged on the wall. Since the image light is absorbed by the optical element 13 (arrow dotted line), no image light is imaged on the optical element 13.

  In the video projection system shown in FIG. 3, the video projection unit 21 is arranged on the front side (observer 25 side) of the video projection body 22, and the optical element 23 exists on the front side of the video projection body 22. Located on the wall. The image light 24 (solid arrow line) projected from the image projection unit 21 forms an image on the image projection target 22 and is visually recognized by an observer, but a part of the image light is reflected by the image projection target 22. To the optical element 23 arranged on the wall. Since the image light is absorbed by the optical element 23 (arrow dotted line), no image light is imaged on the optical element 23.

  In the video projection system shown in FIG. 4, the video projection unit 31 is arranged on the front side (observer 35 side) of the video projection body 32, and the optical element 33 is a ceiling existing above the video projection body 32. Is arranged. The image light 34 (solid arrow line) projected from the image projection unit 31 forms an image on the image projection target 32 and is visually recognized by the observer, but a part of the image light is reflected by the image projection target 32. The optical element 33 arranged on the ceiling is reached. Since the image light is absorbed by the optical element 33 (arrow dotted line), no image light is imaged on the optical element 31.

  Hereinafter, the video projection unit and the video projection target of the video projection system will be described in detail.

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

<Projected image>
An image projection target used in the image projection system has a projection surface that forms an image of image light projected from the projection unit. Examples of the image projection target include a projector transparent screen and a white screen, and it is preferable to use a transparent screen. By installing the above optical element on an object (such as a wall or ceiling) other than a transparent screen, the projection light does not form an image on the optical element, so that an observer can visually recognize an unnecessary image on the object. Can be prevented.

<Transparent screen>
The transparent screen used as the image projection target will be described in detail below. The transparent screen is preferably provided with 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 multilayer structure that further includes other layers such as a protective layer, a base material layer, an adhesive layer, and an antireflection layer. There may be. The transparent screen may include a support such as glass or a transparent partition. The transparent screen can achieve both the visibility of the projection light and the visibility of the transmitted light by anisotropically reflecting 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 video 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, and on the rear side (opposite side of the observer). There may be. The transparent screen may be a flat surface or a curved surface.

  The transparent screen may be a flat surface or a curved surface. For example, the transparent screen can be suitably used for glass windows, head-up displays, wearable displays, and the like. In the present invention, the term “transparent” is sufficient as long as the transparency can be realized according to the application, and includes “translucent”.

  The transparent screen has a haze value of preferably 35% or less, more preferably 1% or more and 30% or less, further preferably 1.5% or more and 25% or less, and particularly preferably 2% or more and 10% or less. It is. Further, the transparent screen preferably has a total light transmittance of 60% or more and 98% or less, more preferably 65% or more and 96% or less, still more preferably 70% or more and 94% or less, and even more. Preferably they are 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 addition, in this invention, the haze value and total light transmittance of a transparent screen are JIS-K-7361 and JIS-K- using a turbidimeter (Nippon Denshoku Industries Co., Ltd. product number: NDH-5000). It can be measured according to 7136.

  The image clarity of the transparent screen is preferably 65% or more, more preferably 70% or more and 98% or less, still more preferably 75% or more and 96% or less, and even more preferably 80% or more and 94%. It is as follows. If the image clarity of the transparent screen is within the above range, the image seen through the transparent screen is very clear. In the present invention, the image clarity is a value of image definition (%) when measured with an optical comb width of 0.125 mm in accordance with JIS K7374.

(Light diffusion layer)
The light diffusion layer includes a binder and fine particles. As the fine particles, the following light reflective fine particles and light reflective fine particles can be suitably used. By using such fine particles, light can be diffused and reflected anisotropically in the light diffusion layer, and the light utilization efficiency can be enhanced.

  The thickness of the light diffusing 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. More preferably, it is 1 μm to 10 mm. If the thickness of the light diffusion layer is within the above range, the strength as a screen is easily maintained. The light diffusion layer may be a molded body obtained 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 diffusion layer may have a single layer structure, or may have a multilayer structure in which two or more layers are laminated by coating or the like, or two or more light diffusion layers are bonded together with an adhesive or the like.

  In order to obtain a highly transparent film, the light diffusion layer preferably uses a highly transparent binder. As the binder, there are an organic binder and an inorganic binder. As the organic binder, a thermoplastic resin, a self-crosslinking resin such as a thermosetting resin and an ionizing radiation curable resin can be used. 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 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 resins, polyester resins, polyolefin resins, cellulose resins, vinyl resins, polycarbonate resins, and polystyrene resins. 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 can be used alone or in combination of two or more.

  Examples of the ionizing radiation curable resin include acrylic, urethane, acrylic urethane, epoxy, and silicone resins. Among these, those having an acrylate-based functional group, such as relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, many Monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone as oligomers or prepolymers such as (meth) arylate of polyfunctional compounds such as polyhydric alcohols and reactive diluents And polyfunctional monomers such as polymethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate Preferred are those containing 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, etc. . Further, the ionizing radiation curable resin may be mixed with a thermoplastic resin and a solvent.

  Examples of thermosetting resins include phenolic resins, epoxy resins, silicone resins, melamine resins, urethane resins, urea resins, and the like. Among 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 refers to a concentrated aqueous solution of alkali silicate, and sodium is usually included 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, a PbO—B ₂ O ₃ system, a PbO—B ₂ O ₃ —SiO ₂ system, a PbO—ZnO—B ₂ O ₃ system, a mixture containing an acid component and a metal chloride is heat-treated. The lead-free low softening point glass etc. which are obtained by this can be mentioned. In order to improve the dispersibility and moldability of the fine particles, a solvent, a high boiling point organic solvent, and the like can be mixed with the low softening point glass material.

  The sol-gel material is a group of compounds that are cured by hydrolysis polycondensation by the action of heat, light, catalyst, and the like. For example, metal alkoxide (metal alcoholate), metal chelate compound, metal halide, liquid glass, spin-on glass, or a reaction product thereof, which may contain a catalyst for promoting curing. Moreover, you may have a photoreactive functional group, such as an acryl group, in a part of metal alkoxide functional group. These may be used alone or in combination of a plurality of types according to the required physical properties. The cured sol-gel material refers to a state in which the polymerization reaction of the sol-gel material has sufficiently progressed. The sol-gel material is chemically bonded to the surface of the inorganic substrate in the course of the polymerization reaction and strongly adheres. Therefore, a stable cured product layer can be formed by using a cured body of a sol-gel material as the cured product layer.

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

  For example, as a metal alkoxide having a metal species of silicon, dimethyldiethoxysilane, diphenyldiethoxysilane, phenyltriethoxysilane, methyltriethoxysilane (MTES), vinyltriethoxysilane, p-styryltriethoxysilane, methylphenyldioxysilane. 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. And the compound group in which the ethoxy group of these compound groups is replaced by a methoxy group, a propyl group, an isopropyl group, a hydroxy group, or the like. Among these, triethoxysilane (TEOS) and tetramethoxysilane (TMOS) in which the ethoxy group of TEOS is replaced 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 as required. 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. Moreover, when the binder of this invention is a liquid, it does not need to contain a solvent.

  Specific examples of the solvent according to the present invention include, for example, alcohols such as methanol, ethanol, isopropyl alcohol (IPA), n-propanol, butanol, 2-butanol, ethylene glycol, 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 and dioxane, acetone, methyl ethyl ketone, isophorone, cyclohexanone and cyclopentanone , Ketones such as N-methyl-2-pyrrolidone, ether ethers such as butoxyethyl ether, hexyloxyethyl alcohol, methoxy-2-propanol and benzyloxyethanol Coles, glycols such as ethylene glycol, 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 ethers such as glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monomethyl ether, 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, N-methylpyrrolidone, halogen solvents such as chloroform, methylene chloride, tetrachloroethane, monochlorobenzene, dichlorobenzene, Examples include hetero-element compounds such as carbon disulfide, water, and mixed solvents thereof. The addition amount of the solvent can be appropriately adjusted according to the type of binder and fine particles, the viscosity range suitable for the production process described later, and the like.

(Light reflecting fine particles)
The light-reflecting fine particles may have any shape, may be substantially spherical, or may be in the form of a flake. When the shape of the light-reflecting fine particles is approximately 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 transmission visibility, so that 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 (trade name: DLS-8000, manufactured by Otsuka Electronics Co., Ltd.). 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, still more preferably 0.1 to 50 μm, and even more preferably 0. .5 to 30 μm. Further, the light reflective fine particles preferably have an average aspect ratio (= average diameter / average thickness of the light reflective fine particles) of 3 to 800, more preferably 4 to 700, still more preferably 5 to 600, and still more preferably. 10-500. When the average diameter and 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 transmission visibility, so that a clear image can be projected on a 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 (trade name: SU-1500, manufactured by Hitachi High-Technologies Corporation) image.

As the flaky light-reflecting fine particles, a glittering material that can be processed into a flaky shape can be suitably 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 reflective fine particles in consideration of the oxidation state and the like.
(Regular reflectance)
A spectrocolorimeter (manufactured by Konica Minolta Co., Ltd., product number: CM-3500d) was used. Light-reflective fine particles dispersed in an appropriate solvent (water or methyl ethyl ketone) were deposited on a slide glass with a film thickness of 0.5 mm. About the obtained glass plate with a coating film, the regular reflectance when light is incident on the coating film portion from the glass surface at an angle of 45 degrees with respect to the normal of the glass surface is obtained. Was measured.

  Depending on the type of 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 composed of diamond and zinc sulfide, a glittering material in which a resin or glass is coated with a metal or a metal oxide, or a glittering material in which a natural mica or synthetic mica is coated with a metal oxide can be used. Commercially available light-reflecting fine particles may be used. For example, aluminum powder manufactured by Daiwa Metal Powder Industry Co., Ltd. can be suitably used.

  The content of the light reflecting fine particles in the light diffusion layer can be appropriately adjusted according to the shape of the light reflecting fine particles, the regular reflectance, and the like. For example, the content of the light reflecting fine particles is preferably 0.0001 to 5.0 mass%, preferably 0.0005 to 3.0 mass%, more preferably 0.001 based on the binder. It is -2.0 mass%. Visually recognizing projected light by anisotropically reflecting and reflecting projected light emitted from a light source by dispersing light-reflecting fine particles in a binder at a low concentration within the above range to form a light diffusion layer And 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, pigments or dyes such as carbon black, azo pigments, anthraquinone pigments, and perinone pigments can be used. Further, a liquid crystal compound or the like may be mixed.

(Base material layer)
A base material layer is a layer for supporting said light-diffusion layer, and can improve the intensity | strength of a 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 and desired optical characteristics. As such a resin, for example, a highly transparent resin similar to the above light diffusion layer can be used. Moreover, you may use the composite film or sheet | seat which laminated | stacked 2 or more types of above-described resin. In addition, the thickness of a base material layer can be suitably changed according to material so that the intensity | strength may become suitable, for example, is good also as the range of 10-1000 micrometers.

(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 and the desired optical characteristics. As such a resin, for example, a resin curable by ultraviolet rays or an electron beam, that is, an ionizing radiation curable resin, a mixture of an ionizing radiation curable resin and a thermoplastic resin and a solvent, and a thermosetting resin are used. Among these, ionizing radiation curable resins are particularly preferable.

  The film forming component of the ionizing radiation curable resin composition is preferably one having an acrylate functional group, such as a relatively low molecular weight polyester resin, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, Spiroacetal resin, polybutadiene resin, polythiol polyene resin, oligomers or prepolymers such as (meth) arylate of polyfunctional compounds such as polyhydric alcohols, and reactive diluents such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, Monofunctional monomers such as methylstyrene and N-vinylpyrrolidone as well as polyfunctional monomers such as polymethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate 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. A large amount can be used.

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

  As a curing method of the ionizing radiation curable resin composition, the curing method of the ionizing radiation curable resin composition can be cured by a normal curing method, that is, irradiation with an electron beam or ultraviolet rays. For example, in the case of electron beam curing, 50 to 50 emitted from various electron beam accelerators such as a Cockloft Walton type, a bandegraph type, a resonant transformation type, an insulating core transformer type, a linear type, a dynamitron type, and a high frequency type An electron beam having an energy of 1000 KeV, preferably 100 to 300 KeV is used. In the case of ultraviolet curing, ultraviolet rays emitted from rays such as ultra-high pressure mercury lamp, high pressure mercury lamp, low pressure mercury lamp, carbon arc, xenon arc, metal halide lamp, etc. Available.

  The protective layer is a method such as spin coating, die coating, dip coating, bar coating, flow coating, roll coating, gravure coating, etc., on the light diffusing layer using the ionizing radiation (ultraviolet) ray curable resin composition coating solution. Then, it can be formed by applying to the surface of the light diffusing layer and curing the coating solution by the means as described above. In addition, a fine structure such as a concavo-convex structure, a prism structure, or a microlens structure can be provided on the surface of the protective layer according to the purpose.

(Adhesive layer)
The adhesive layer is a layer for attaching a film to a 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 and desired optical characteristics. Examples of the pressure-sensitive adhesive composition include natural rubber, synthetic rubber, acrylic resin, polyvinyl ether resin, urethane resin, and silicone resin. Specific examples of synthetic rubbers 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 system include dimethylpolysiloxane. These pressure-sensitive adhesives can be used singly or in combination of two or more. Among these, an acrylic adhesive is preferable.

  The acrylic resin pressure-sensitive adhesive is a polymer containing at least a (meth) acrylic acid alkyl ester monomer. Generally, it is 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, (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. Moreover, the said (meth) acrylic-acid alkylester is normally copolymerized in the ratio of 30-99.5 mass parts in the acrylic adhesive.

  Moreover, as a monomer which has a carboxyl group which forms acrylic resin adhesive, the monomer containing carboxyl groups, such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, monobutyl maleate, and (beta) -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 that does not impair the characteristics of the acrylic resin pressure-sensitive adhesive. Examples of monomers having other functional groups include monomers containing hydroxyl groups such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 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; Monomers having functional groups such as amino group-containing monomers such as meth) acrylate, dimethylaminoethyl (meth) acrylate and vinylpyridine; epoxy group-containing monomers such as allyl glycidyl ether and (meth) acrylic acid glycidyl ether Chromatography and the like. In addition, fluorine-substituted (meth) acrylic acid alkyl ester, (meth) acrylonitrile and the like, vinyl group-containing aromatic compounds such as styrene and methylstyrene, vinyl acetate, and vinyl halide compounds can be used.

  Commercially available adhesives may be used, such as SK Dyne 2094, SK Dyne 2147, SK Dyne 1811L, SK Dyne 1442, SK Dyne 1435, and SK Dyne 1415 (above, manufactured by Soken Chemical Co., Ltd.), Olivain EG-655, Olivevine BPS5896 (above, manufactured by Toyo Ink Co., Ltd.), etc. (above, trade name) can be suitably used.

(Antireflection layer)
The antireflection layer is a layer for preventing reflection on the outermost surface of the transparent screen and reflection from outside light. The antireflection layer may be laminated on at least one side of the transparent screen, preferably on the surface side (observer side), or may be laminated on both sides. In particular, when 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 and desired optical characteristics of the transparent screen. As such a resin, for example, a resin curable by ultraviolet rays or an electron beam, that is, an ionizing radiation curable resin, a mixture of an ionizing radiation curable resin and a thermoplastic resin and a solvent, and a thermosetting resin are used. Among these, ionizing radiation curable resins are particularly preferable. Further, the surface of the antireflection layer can be provided with a fine structure such as a concavo-convex structure, a prism structure, or a microlens structure depending on the purpose.

  The method for forming the antireflection layer is not particularly limited, but is a method of pasting a coating film, a method of dry coating directly on a film substrate by vapor deposition or sputtering, gravure coating, micro gravure coating, bar coating, slide die coating. Methods such as wet coating such as coating, slot die coating, and 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 above layers. Examples of the functional layer include a light absorbing layer containing a dye or a colorant, a light diffusing layer such as a prism sheet, a microlens sheet, a Fresnel lens sheet, and a lenticular lens sheet, and a light cut layer such as an ultraviolet ray and an infrared ray. It is done.

(Transparent screen manufacturing method)
The manufacturing method of a transparent screen includes the process of forming a light-diffusion layer. The process of forming the light diffusion layer consists of a kneading process and a film forming process, an extrusion molding method, a cast film forming method, a gravure coating, a micro gravure coating, a bar coating, a slide die coating, and a slot die coating. , Coating methods including dip coating, spraying method, injection molding method, calendar molding method, blow molding method, compression molding method, cell casting method, etc., can be molded by known methods, such as extrusion molding method, injection molding method, coating method Can be suitably 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 lamination method of each layer is not specifically limited, It can carry out by a conventionally well-known method. In the case of laminating each layer by dry lamination, an adhesive or the like may be used as long as the transparent visibility of the transparent screen and desired optical characteristics are not impaired.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is limited to the following Example and is not interpreted.

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

[Example 1]
First, the optical axis is tilted by 45 degrees on a linear polarizing plate (polarization degree 99.82%, single transmittance: 40%, manufactured by Polatechno Co., Ltd., trade name: SHC-125U, with adhesive layer), 1/4 wavelength. A board (manufactured by Teijin Chemicals Ltd., trade name: Pure Ace RM) was bonded to obtain a laminate. On the quarter wave plate side of this laminate, a reflector (made by Toray Industries, Ltd., Metal Me TS50) is further laminated via an optical adhesive film (trade name PD-S1 manufactured by Panac Co., Ltd.) An optical element was obtained.

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

After installing the transparent screen obtained above in a room with walls and ceiling, install a video projection unit (AddTron Technology Co., Ltd. QUMI Q6) on the front side (observer side) of the transparent screen, and transparent The optical element obtained above was installed on the rear wall (opposite to the observer) of the screen to produce a video projection system (embodiment of FIG. 2). Subsequently, image light was projected from the image projection unit onto a transparent screen. It was visually evaluated according to the following criteria whether or not an observer can visually recognize an unnecessary image on the wall on which the optical element by the light transmitted through the transparent screen is installed. The luminance on the rear wall when no optical element is installed is 72.7 cd / cm ² (Comparative Example 1), and the luminance on the rear wall when an optical element is installed is 1.0 cd / cm ^2. cm ^2, and it was confirmed that the transmitted light is greatly absorbed.

[Example 2]
A video projection system was manufactured in the same manner as in Example 1 except that the optical element was installed on the front wall of the transparent screen (embodiment of FIG. 3). Subsequently, image light was projected from the image projection unit onto the transparent screen in the same manner as in Example 1. It was visually evaluated according to the following criteria whether or not an observer could visually recognize an unnecessary image on the wall on which the optical element by the light reflected from the transparent screen was installed. The luminance on the front side wall when no optical element is installed is 8.5 cd / cm ² (Comparative Example 3), and the luminance on the front side wall when the optical element is installed is 0.4 cd / cm ^2. cm ^2, and it was confirmed that the reflected light is greatly 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 in FIG. 4). Subsequently, image light was projected from the image projection unit onto the transparent screen in the same manner as in Example 1. It was visually evaluated according to the following criteria whether or not an observer can visually recognize an unnecessary image on the ceiling on which the optical element by the light reflected from the transparent screen is installed. Moreover, the brightness | luminance in the ceiling when an optical element is not installed is 10.8 cd / cm < ² > (comparative example 4), the brightness | luminance in the ceiling when an optical element is installed is 0.5 cd / cm < ² >, and reflection It was confirmed that the light was significantly absorbed.

[Example 4]
An optical element was obtained in the same manner as in Example 1 except that the reflector was not laminated. Next, a video projection system was produced in the same manner as in Example 1. Subsequently, image light was projected from the image projection unit onto the transparent screen in the same manner as in Example 1. Whether or not an observer can visually recognize an unnecessary image on the rear wall on which the optical element by the light transmitted through the transparent screen is installed was evaluated visually according to the following criteria. The luminance on the rear side wall when no optical element is installed is 72.7 cd / cm ² (Comparative Example 1), and the luminance on the rear side wall when the optical element is installed is 13.7 cd / cm ^2. It was cm ² and it was confirmed that transmitted light was absorbed.

[Example 5]
The optical element produced in Example 1 was installed on the wall of a room having a wall and a ceiling, and image light was directly projected from the image projection unit used in Example 1 onto the wall on which the optical element was installed. It was visually evaluated according to the following criteria whether or not an observer can visually recognize an unnecessary image on the wall on which the optical element by the image light is installed. Moreover, the brightness | luminance in the wall when not installing an optical element is 84.0 cd / cm < ² > (comparative example 2), the brightness | luminance in the wall in which the optical element was installed is 1.2 cd / cm < ² >, and it is a direct white plain It was confirmed that the projection light was absorbed even though the image was projected.

[Example 6]
The optical element produced in Example 4 was installed on the wall of a room having a wall and a ceiling, and image light was directly projected from the image projection unit used in Example 1 onto the wall on which the optical element was installed. It was visually evaluated according to the following criteria whether or not an observer can visually recognize an unnecessary image on the wall on which the optical element by the image light is installed. Moreover, the brightness | luminance in the wall at the time of not installing an optical element is 84.0 cd / cm < ² > (Comparative Example 2), the brightness | luminance in the wall in which the optical element was installed is 16.3 cd / cm < ² >, and is a direct white plain It was confirmed that the projection light was absorbed even though the image was projected.

[Comparative Example 1]
A video projection system was produced in the same manner as in Example 1 except that no optical element was installed. Subsequently, image light was projected from the image projection unit onto the transparent screen in the same manner as in Example 1. Whether or not an observer can visually recognize an unnecessary image on the rear-side wall due to light transmitted through the transparent screen was visually evaluated according to the following criteria. The luminance on the rear wall was 72.7 cd / cm ² .

[Comparative Example 2]
In the same manner as in Example 5 except that no optical element was installed, image light was projected from the image projection unit used in Example 1 onto the wall where no optical element was installed. It was visually evaluated according to the following criteria whether or not an observer can visually recognize an unnecessary image on the wall on which no optical element is installed. The luminance on the wall where no optical element was installed was 84.0 cd / cm ² .

[Comparative Example 3]
A video projection system was produced in the same manner as in Example 2 except that no optical element was installed. Subsequently, image light was projected from the image projection unit toward the transparent screen in the same manner as in Example 2. Whether or not an observer can visually recognize an unnecessary image on the front-side wall due to light reflected from the transparent screen was visually evaluated according to the following criteria. The luminance at the front wall was 8.5 cd / cm ² .

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

[Evaluation criteria]
A: The observer could not visually recognize an unnecessary image on the object (ceiling, wall, etc.) on which the optical element was installed.
(Triangle | delta): Although the observer could visually recognize the unnecessary image slightly on the objects (ceiling, wall, etc.) which the optical element installed, the image was thin.
X: The observer could visually recognize an unnecessary image on an object (ceiling, wall, etc.) on which the optical element was not installed.

The evaluation results are shown in Table 1.

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

Claims (13)

An optical element used in a video projection system including a video projection unit and installed on an object other than a video projection object,
An optical element in which the image light projected from the image projection unit does not form an image.   The optical element according to claim 1, wherein the optical element comprises a circularly polarizing plate.   The optical element according to claim 2, wherein the optical element further comprises a reflector.   The optical element according to claim 2, wherein the circularly polarizing plate includes a linearly polarizing plate and a quarter wavelength plate.   The optical element according to claim 4, wherein the circularly polarizing plate further includes an adhesive layer between the linearly polarizing plate and the quarter-wave plate.   The optical element according to claim 3, wherein the optical element further includes an adhesive layer between the circularly polarizing plate and the reflecting plate. A video projection system comprising: a video projection unit; and the optical element according to any one of claims 1 to 6 installed on an object other than a video projection object,
An image projection system in which image light projected from the image projection unit does not form an image on the optical element.   The video projection system according to claim 7, wherein the video projection system further includes a transparent screen as a video projection target.   The image projection system according to claim 8, wherein light transmitted through the transparent screen or light reflected by the transparent screen among the image light projected from the image projection unit does not form an image on the optical element. The transparent screen is a reflective transparent screen;
The image projection system according to claim 8 or 9, wherein the optical element is installed on an object other than the reflective transparent screen, and the image light projected from the image projection unit does not form an image on the optical element. The transparent screen is a transmissive transparent screen;
The video projection system according to claim 8 or 9, wherein the optical element is installed on an object other than the transparent screen, and video light projected from the video projection unit does not form an image on the optical element.   The video projection system according to claim 8, wherein the transparent screen has a haze value of 35% or less.   The video projection system according to claim 8, further comprising an antireflection layer on at least one side of the transparent screen.