JP2020166055A - Video projection system - Google Patents

Abstract

To provide a video projection system that can suppress reflection light on a surface of a transparent screen from causing unnecessary image-formation in a floor, ground surface or ceiling, as video light from a video projection unit is image-forming on the transparent screen.SOLUTION: A video projection unit comprises: a transparent screen 11; a video projection unit 13 that is arranged on a front side of the transparent screen; and a transparent viewing angle control film 12 that is arranged between the transparent screen and the video projection unit. The video projection unit is arranged so that a reflection angle α of video light 15 falls within a range of a viewing angle control angle β of the transparent viewing angle control film in a surface on a transparent viewing angle control film side of the transparent screen. The video light projected from the video projection unit is image-formed on the transparent screen, and reflection light 16 upon the surface on the transparent viewing angle control film side of the transparent screen is scattered by the transparent viewing angle control film.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image projection system including a transparent screen, an image projection unit arranged on the front side of the transparent screen, and a transparent viewing angle control film arranged between the transparent screen and the image projection unit.

Conventionally, in an image projection system, it is common that an image projection unit projects image light onto an image projecting object such as a screen, and an observer observes the image. In recent years, there has been an increasing demand for projecting product information, advertisements, etc. on show windows of department stores, transparent partitions of event spaces, walls, etc. using such an image projection system. In order to meet such demands, a transparent screen may be attached to a show window, a transparent partition, a wall, etc., but it is reflected by the surface of the transparent screen among the image light projected from the image projection unit. There is a problem that the emitted light reaches the floor, the ground or the ceiling on the front side (observer side) and causes an unnecessary image formation, which hinders comfortable viewing or hinders the production.

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 projection unit side in order to reduce the reflection of the image on the ceiling as much as possible. (Patent Documents 1 and 2). However, the reflective screens described in Patent Documents 1 and 2 are not transparent and have no transparent visibility of the screen. Therefore, the reflective screens described in Patent Documents 1 and 2 cannot be used in applications that require transmission visibility, for example, in show windows such as department stores and transparent partitions in event spaces. Therefore, in an image projection system using a transparent screen, it is required to be able to reduce the reflection of an image on the floor, the ground, or the ceiling on the front side.

Japanese Unexamined Patent Publication No. 2013-1330837 Japanese Unexamined Patent Publication No. 2014-71278 Japanese Unexamined Patent Publication No. 51-44186 Japanese Unexamined Patent Publication No. 50-26885 JP-A-2-97904 Japanese Patent No. 2547417

When the transparent screen is used, the present inventors have a reflection on the floor, the ground or the ceiling on the front side due to the reflection of the image light on the surface, as compared with the reflective transparent screen described in Patent Documents 1 and 2. We found the problem of being severe and hindering comfortable visual recognition.

The present invention has been made in view of the above technical problems, and an object of the present invention is to provide an image light from an image projection unit in an image projection system including a transparent screen and an image projection unit arranged on the front side of the transparent screen. It is an object of the present invention to provide an image projection system capable of suppressing an unnecessary image formation on the floor, the ground or the ceiling while the image is formed on the transparent screen.

As a result of diligent studies to solve the above technical problems, the present inventors have found that a transparent screen and an image projection unit are used in an image projection system including a transparent screen and an image projection unit arranged on the front side of the transparent screen. By arranging the transparent viewing angle control film between them and arranging the image projection unit so that the reflection angle of the image light on the surface of the transparent screen is within the range of the viewing angle control angle of the transparent viewing angle control film. , It was found that the above technical problems can be solved. The present invention has been completed based on such findings.

That is, according to one aspect of the present invention.
An image projection system including a transparent screen, an image projection unit arranged on the front side of the transparent screen, and a transparent viewing angle control film arranged between the transparent screen and the image projection unit.
The image projection unit is arranged so that the reflection angle of the image light on the surface of the transparent screen on the transparent viewing angle control film side is within the range of the viewing angle control angle of the transparent viewing angle control film.
The image light projected from the image projection unit is imaged on the transparent screen.
An image projection system is provided in which the reflected light on the surface of the transparent screen on the transparent viewing angle control film side is scattered by the transparent viewing angle control film.

In the above aspect of the present invention, it is preferable that the upper limit of the range of the projection angle of the image light of the image projection unit is within the range of the viewing angle control angle of the transparent viewing angle control film.

In the above aspect of the present invention, the viewing angle control angle of the transparent viewing angle control film is preferably 10 degrees or more and 80 degrees or less.

In the above aspect of the present invention, the transparent viewing angle control film has a parallel ray transmission rate of 0% or more and less than 40% within the viewing angle control angle range, and parallel rays outside the viewing angle control angle range. The permeability is preferably 60% or more and 92% or less.

In the above aspect of the present invention, it is preferable that the transparent screen and the transparent viewing angle control film form a laminate.

In the above aspect of the present invention, it is preferable that the laminate includes a transparent layer between the transparent screen and the transparent viewing angle control film.

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

In the above aspect of the present invention, it is preferable that the transparent screen contains a light-reflecting material.

In the above aspect of the present invention, it is preferable that the transparent screen is at least a part of a vehicle member.

In the above aspect of the present invention, it is preferable that the transparent screen is at least a part of a building member.

According to the present invention, in an image projection system including a transparent screen and an image projection unit arranged on the front side of the transparent screen, a transparent viewing angle control film is arranged between the transparent screen and the image projection unit, and the transparent screen. By arranging the image projection unit so that the reflection angle of the image light on the surface of the transparent viewing angle control film is within the range of the viewing angle control angle of the transparent viewing angle control film, the transparent viewing angle control film is transmitted. While the image light is imaged on the transparent screen, the reflected light on the surface of the transparent screen on the transparent viewing angle control film side is scattered by the transparent viewing angle control film, so that the reflected light is unnecessary on the floor, ground or ceiling. It is possible to suppress the occurrence of various imaging (image reflection). According to such an image projection system, it is possible to prevent unnecessary imaging from hindering comfortable visual recognition or hindering the production.

It is a conceptual diagram which shows the projection image system of 1st Embodiment by this invention. It is a conceptual diagram which shows the projection image system of the modification of 1st Embodiment by this invention. It is a conceptual diagram which shows the projection image system of the 2nd Embodiment by this invention. It is a photograph which shows the observation result from the front side (observer side) of the transparent screen in the projection image system of Example 1. FIG. It is a photograph showing the observation result from the front side (observer side) of the transparent screen in the projection image system of Comparative Example 1.

<Video projection system>
The image projection system according to the present invention includes a transparent screen, an image projection unit arranged on the front side of the transparent screen, and a transparent viewing angle control film arranged between the transparent screen and the image projection unit. The image projection unit is arranged so that the reflection angle of the image light from the projection unit is within the viewing angle control angle of the transparent viewing angle control film. In such an image projection system, the image light projected from the image projection unit is imaged on the transparent screen, and the reflected light on the surface of the transparent screen on the transparent viewing angle control film side is generated by the transparent viewing angle control film. By being scattered, it is possible to prevent the reflected light from forming an unnecessary image on the floor, the ground, or the ceiling. According to such an image projection system, it is possible to prevent unnecessary imaging from hindering comfortable visual recognition or hindering the production.

In the present invention, "transparent" means that it is sufficient if it is transparent enough to realize transmission visibility according to the application, and it also includes translucency.
In the present invention, the "viewing angle control angle of the transparent viewing angle control film" is an orthogonal plane (vertical line) in the thickness direction of the transparent viewing angle control film with the surface (interface) of the transparent viewing angle control film on the transparent screen side as a base point. ) Is specified by the angle formed.
In the present invention, the "reflection angle of image light" is formed by reflecting light with respect to an orthogonal plane (perpendicular line) in the thickness direction of the transparent screen with the surface (interface) on the transparent viewing angle control film side of the transparent screen as a base point. Specified by angle.
In the present invention, the "projection angle of image light" is defined by the angle formed by the image light with respect to the orthogonal plane (perpendicular line) of the transparent screen with the image projection unit as a base point.
In the present invention, the "front side" refers to the direction of the observer side display surface of the transparent screen.

A conceptual diagram of the image projection system according to the first embodiment of the present invention is shown in FIG. The image projection system shown in FIG. 1 includes a transparent screen 11, an image projection unit 13 arranged on the front side of the transparent screen 11, and a transparent viewing angle control film 12 arranged between the transparent screen 11 and the image projection unit 13. And. In the first embodiment, the image projection unit 13 projects the image light 15 onto the observer 18 from above. At that time, the image projection unit 13 is arranged so that the reflection angle α of the image light from the image projection unit 13 is within the range 17 of the viewing angle control angle β of the transparent viewing angle control film 12. When the image light 15 is projected from the image projection unit 13, an image is formed on the transparent screen 11, but a part of the image light 15 is reflected on the surface of the transparent screen 11 on the transparent viewing angle control film 12 side. Since the reflected light 16 is scattered by the transparent viewing angle control film 12, the reflected light 16 does not cause an unnecessary image formation on the floor 20. The upper limit of the range of the projection angle γ of the image light 15 of the image projection unit 13 is larger than the lower limit of the range 17 of the viewing angle control angle β of the transparent viewing angle control film 12, so that a part of the reflected light 16 is It is easily scattered by the transparent viewing angle control film 12 to suppress unnecessary imaging on the floor 20. In FIG. 1, the image light 15 projected from the image projection unit 13 reaches the transparent screen 11 without passing through the transparent viewing angle control film 12, but the position and size of the transparent viewing angle control film 12 are changed. You may reach the transparent screen 11 after passing through the transparent viewing angle control film 12 by such means.

FIG. 2 shows a conceptual diagram of a modified example of the image projection system according to the first embodiment of the present invention. In FIG. 1, the transparent screen and the transparent viewing angle control film are separated from each other, but in FIG. 2, the transparent screen and the transparent viewing angle control film are close to each other to form a laminated body. Specifically, the image projection system shown in FIG. 2 has a transparent screen 21, an image projection unit 23 arranged on the front side of the transparent screen 21, and a transparency arranged between the transparent screen 21 and the image projection unit 23. A viewing angle control film 22 is provided. In the first embodiment, the image projection unit 23 projects the image light 25 from above to the observer 28. At that time, the image projection unit 23 is arranged so that the reflection angle α of the image light from the image projection unit 23 is within the range 27 of the viewing angle control angle β of the transparent viewing angle control film 22. When the image light 25 is projected from the image projection unit 23, an image is formed on the transparent screen 21, but a part of the image light 25 is reflected on the surface of the transparent screen 21 on the transparent viewing angle control film 22 side. Since the reflected light 26 is scattered by the transparent viewing angle control film 22, the reflected light 26 does not cause an unnecessary image formation on the floor 30. The upper limit of the range of the projection angle γ of the image light 25 of the image projection unit 23 is larger than the lower limit of the range 27 of the viewing angle control angle β of the transparent viewing angle control film 22, so that a part of the reflected light 26 is partially reflected. It is easily scattered by the transparent viewing angle control film 22 to suppress unnecessary imaging on the floor 30. In FIG. 2, the image light 25 projected from the image projection unit 23 reaches the transparent screen 21 after passing through the transparent viewing angle control film 22, but the position and size of the transparent viewing angle control film 22 are changed. The transparent screen 21 may be reached without passing through the transparent viewing angle control film 22.

A conceptual diagram of the image projection system according to the second embodiment of the present invention is shown in FIG. The image projection system shown in FIG. 3 includes a transparent screen 31, an image projection unit 33 arranged on the front side of the transparent screen 31, and a transparent viewing angle control film 32 arranged between the transparent screen 31 and the image projection unit 33. And. In the second embodiment, the image projection unit 33 projects the image light 35 from below to the observer 38. At that time, the image projection unit 33 is arranged so that the reflection angle α of the image light from the image projection unit 33 is within the range 37 of the viewing angle control angle β of the transparent viewing angle control film 32. When the image light 35 is projected from the image projection unit 33, an image is formed on the transparent screen 31, but a part of the image light 35 is reflected on the surface of the transparent screen 31 on the transparent viewing angle control film 32 side. Since the reflected light 36 is scattered by the transparent viewing angle control film 32, the reflected light 36 does not cause an unnecessary image formation on the ceiling 40. Since the upper limit of the range of the projection angle γ of the image light 35 of the image projection unit 33 is within the range 37 of the viewing angle control angle β of the transparent viewing angle control film 32, a part of the reflected light 36 is a transparent viewing angle. It is easily scattered by the control film 32 to suppress unnecessary imaging on the ceiling 40. In FIG. 3, the image light 35 projected from the image projection unit 33 reaches the transparent screen 31 after passing through the transparent viewing angle control film 32, but the position and size of the transparent viewing angle control film 32 are changed. The transparent screen 31 may be reached without passing through the transparent viewing angle control film 32.

In the image projection system of the first and second embodiments of the present invention, the transparent screen and the transparent viewing angle control film may be separated as shown in FIG. 1, and may be close to each other as shown in FIGS. 2 and 3. You may be doing it. In particular, it is preferable that the transparent screen and the transparent viewing angle control film are close to each other, and it is more preferable to form a laminated body. By forming the transparent screen and the transparent viewing angle control film into a laminate, it is possible to suppress interfacial reflection and unnecessary diffuse reflection of image light at the air interface of the transparent screen and the transparent viewing angle control film, and further improve the contrast. .. Further, the laminated body makes it easy to arrange the image projection system. Further, by forming the laminated body, a good image with less out-of-focus and deterioration of resolution can be obtained by forming an image on the transparent screen before the image light diffused and transmitted through the transparent viewing angle control film is dissipated.

Hereinafter, the image projection unit, the transparent screen, and the transparent viewing angle control film, which are the components of the image projection system, will be described in detail.

<Image projection unit>
The image projection unit used in the image projection system is not particularly limited as long as it can project an image on the following transparent screen, and for example, a commercially available rear projector or front projector can be used. In particular, since the projection angle of the image light can be easily adjusted within the range of the viewing angle control angle of the transparent viewing angle control film, the WX450ST manufactured by Canon Inc., which has a lens shift function, can be preferably used.

<Transparent screen>
The transparent screen used in the image projection system preferably includes a light scattering layer containing a binder and a light reflecting material. The transparent screen may have a single-layer structure consisting of only a light scattering layer, or may be a multi-layer structure further including other layers such as a protective layer, a base material layer, an adhesive layer, and an antireflection layer. There may be. Further, the transparent screen may be provided with a support such as glass or a transparent partition. The transparent screen can achieve both the visibility of the projected light and the visibility of the transmitted light by diffuse-reflecting the projected light emitted from the image projection unit.

The transparent screen may be a flat surface or a curved surface. For example, the transparent screen can be suitably used for a glass window, a head-up display, a wearable display, and the like, and can be particularly preferably used as a transparent screen for a short-focus projector.

The transparent screen has a haze value of preferably 35% or less, more preferably 1% or more and 30% or less, and further preferably 2% or more and 25% or less. In addition, the transparent screen has a total light transmittance of preferably 60% or more, more preferably 65% or more and 98% or less, more preferably 70% or more and 96% or less, and further preferably 75%. It is 94% or more, and even more preferably 80% 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 transmitted 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 haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., product number: SH-7000) in accordance with JIS K 7136 and JIS K 7361. can do.

The transparent screen has a mapping property of preferably 65% or more, more preferably 70% or more and 98% or less, still more preferably 75% or more and 97% or less, and even more preferably 80% or more and 96%. It is as follows. If the image quality of the transparent screen is within the above range, the image seen through the transparent screen becomes extremely clear. In the present invention, the mapability is a value of image sharpness (%) when measured with an optical comb width of 0.125 mm in accordance with JIS K 7374.

(Light scattering layer)
The light scattering layer comprises a binder and a light reflective material. As the light-reflecting material, the following light-reflecting fine particles, magnetic fine particles, and the like can be preferably used. By using such a light-reflecting material, light can be anisotropically diffuse-reflected in the light scattering layer to improve the efficiency of light utilization.

The thickness of the light scattering layer is not particularly limited, but is preferably 0.1 μm to 20 mm, more preferably 0.2 μm to 15 mm from the viewpoint of application, productivity, handleability, and transportability. It is more preferably 1 μm to 10 mm. When the thickness of the light scattering layer is within the above range, the strength of the screen can be easily maintained. The light scattering layer may be a molded product obtained by using the following organic binder or inorganic binder, or may be a coating film formed on a base material made of glass, resin, or the like. The light scattering 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 scattering layers are bonded together with an adhesive or the like.

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

As the highly transparent thermoplastic resin, acrylic resin, polyester resin, polyolefin resin, cellulose resin, vinyl resin, polycarbonate resin, and polystyrene resin are preferably used, and polymethyl methacrylate resin, It is more preferable to use polyethylene terephthalate resin, polyethylene naphthalate resin, polypropylene resin, cycloolefin polymer resin, cellulose acetate propionate resin, polyvinyl butyral resin, nitrocellulose resin, polycarbonate resin, and polystyrene resin. These resins can be used alone or in combination of two or more.

Examples of the highly transparent ionizing radiation curable resin include acrylic-based and urethane-based resins, acrylic urethane-based and epoxy-based resins, and silicone-based resins. Among these, those having an acrylate-based functional group, for example, polyester resin having a relatively low molecular weight, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin, polybutagen resin, polythiol polyene resin, many Monofunctional monomers such as (meth) alrilate of polyfunctional compounds such as valent alcohols, or monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, and N-vinylpyrrolidone as reactive diluents. Also, polyfunctional monomers such as polymethylol propantri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol. Those containing a relatively large amount of hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate and the like are preferable. Further, the ionizing radiation curable resin may be a mixture of a thermoplastic resin and a solvent. A commercially available product can be used as the ionizing radiation curable resin, and for example, a urethane acrylate type UV curable resin manufactured by DIC Corporation (trade name: Unidic V-4025) or the like can be used.

Examples of the highly transparent thermosetting resin include phenolic resin, epoxy resin, silicone resin, melamine resin, urethane resin, urea resin 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 an alkali silicate, and usually contains sodium as an alkali metal. A typical water glass can be represented by Na ₂ O · nSiO ₂ (n: an arbitrary number of positives), and soda silicate manufactured by Fuji Chemical Co., Ltd. can be used as a commercially available product.

The glass material having a low softening point is a glass having a softening temperature preferably in the range of 150 to 620 ° C, more preferably a softening temperature in the range 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 mixture containing PbO-B ₂ O ₃ system, PbO-B ₂ O _3- SiO ₂ system, PbO-ZnO-B ₂ O ₃ system, an acid component and a metal chloride is heat-treated. The lead-free low-softening point glass obtained by the above can be mentioned. A solvent, a high boiling point organic solvent, or the like can be mixed with the low softening point glass material in order to improve the dispersibility and moldability of the fine particles.

A sol-gel material is a group of compounds in which hydrolysis polycondensation proceeds and cures due to the action of heat, light, a catalyst, or the like. For example, a metal alkoxide (metal alcoholate), a metal chelate compound, a metal halide, a liquid glass, a spin-on glass, or a reaction product thereof, which may contain a catalyst that promotes 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 proceeded. The sol-gel material chemically bonds with the surface of the inorganic substrate in the process of the polymerization reaction and adheres strongly. Therefore, a stable cured product layer can be formed by using a cured product of a sol-gel material as the cured product layer.

A metal alkoxide is a group of compounds obtained by reacting an arbitrary metal species with water or an organic solvent using a hydrolysis catalyst or the like. The metal alkoxide is a group of compounds obtained by reacting any metal species with water or an organic solvent. 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 and tin.

For example, metal alkoxides whose metal type is silicon include dimethyldiethoxysilane, diphenyldiethoxysilane, phenyltriethoxysilane, methyltriethoxysilane (MTES), vinyltriethoxysilane, p-styryltriethoxysilane, and methylphenyldi. 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-aminopropyltriethoxy Silane, 3-aminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropyltriethoxysilane, triethoxysilane, diphenylsilanediol, dimethylsilanediol, etc. Examples thereof include a group of compounds in which the ethoxy group of the compound group is replaced with a methoxy group, a propyl group, an isopropyl group, a hydroxy group and the like. Among these, triethoxysilane (TEOS) and tetramethoxysilane (TMS) 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, if necessary. The solvent is not limited to the organic solvent, and any solvent used in general coating compositions can be used. For example, a hydrophilic solvent such as water can also be used. Further, when the binder of the present invention is a liquid, it does not have to contain a solvent.

Specific examples of the solvent include, for example, alcohols such as methanol, ethanol, isopropyl alcohol (IPA), n-propanol, butanol, 2-butanol, ethylene glycol and propylene glycol, hexane, heptane, octane, decane and cyclohexane. Arophilic hydrocarbons such as aliphatic hydrocarbons, benzene, toluene, xylene, mesitylene and tetramethylbenzene, ethers such as diethyl ether, tetrahydrofuran and dioxane, acetone, methyl ethyl ketone, isophorone, cyclohexanone, cyclopentanone, N- Ketones such as methyl-2-pyrrolidone, butoxyethyl ether, hexyloxyethyl alcohol, ether alcohols such as methoxy-2-propanol and benzyloxyethanol, glycols such as ethylene glycol and propylene glycol, ethylene glycol dimethyl ether and diethylene glycol dimethyl ether. , Propropylene 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 Glycol ethers such as monoethyl ether, triethylene glycol monomethyl ether and triethylene glycol monoethyl ether, esters such as ethyl acetate, butyl acetate, ethyl lactate and γ-butyrolactone, solvents such as phenol and chlorophenol, N, Amidos such as N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone, halogen-based solvents such as chloroform, methylene chloride, tetrachloroethane, monochlorobenzene and dichlorobenzene, and heteroelement compounds containing heterocarbon such as carbon disulfide. Examples include water and a mixed solvent thereof. The amount of the solvent added can be appropriately adjusted according to the type of binder and fine particles, the viscosity range suitable for the manufacturing process described later, and the like.

(Light reflective fine particles)
The light-reflecting fine particles are not particularly limited in shape, and may be substantially spherical, flaky, or needle-shaped. 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 clear image can be projected on the transparent screen by obtaining a sufficient scattering effect of the projected light without impairing the transmitted visibility. .. In the present invention, the median diameter (D ₅₀ ) of the primary particles of the light-reflecting fine particles is determined by a particle size distribution measuring device (manufactured by Otsuka Electronics Co., Ltd., trade name: DLS-8000) by a dynamic light scattering method. It can be obtained 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-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. 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 clear image can be projected on the transparent screen by obtaining a sufficient scattering effect of the projected light without impairing the transmitted visibility. it can. In the present invention, the average diameter of the light-reflecting fine particles was measured using a laser diffraction type particle size distribution measuring device (manufactured by Shimadzu Corporation, product number: SALD-2300). The average aspect ratio was calculated from SEM (manufactured by Hitachi High-Technologies Corporation, trade name: SU-1500) image.

As the flaky light-reflecting fine particles, a brilliant material that can be processed into flakes can be preferably used. The specular 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 specular reflectance of the light-reflecting fine particles is a value measured as follows.
(Specular reflectance)
Measured using a spectrophotometer (manufactured by Konica Minolta Co., Ltd., product number: CM-3500d. A powder material dispersed in an appropriate solvent (water or methyl ethyl ketone) is placed on a slide glass with a film thickness of 0.5 mm or more. With respect to the obtained glass plate with a coating film, the positive reflectance of the coating film portion from the glass surface was measured.

The light-reflecting fine particles may be, for example, aluminum, silver, copper, platinum, gold, titanium, nickel, tin, tin-cobalt alloy, indium, chromium, titanium oxide, zinc oxide, depending on the type of binder to be dispersed. Metallic particles consisting of tin oxide, zirconium oxide, cerium oxide, lead oxide, indium oxide, aluminum oxide, and zinc sulfide, glittering materials with glass coated with metal or metal oxide, or metal oxidation on natural or synthetic mica. A brilliant material coated with an object can be used. Commercially available light-reflecting fine particles may be used, and for example, aluminum powder manufactured by Daiwa Metal Powder Industry Co., Ltd. can be preferably used.

Diamond can also be used as the light-reflecting fine particles. As the diamond, it is preferable to use nanodiamond particles having a median diameter of 100 to 400 nm. Since nanodiamond particles have a high refractive index, they have excellent light scattering ability. As a result, since the effect is exhibited with a small amount of addition, multiple scattering and the like, which is one of the causes of clouding, can be suppressed, and a sufficient function can be exhibited with a thickness of about several μm to several tens of μm. The refractive index of the nanodiamond particles is 2.4, which is higher than the refractive index of general resins (about 1.5 to 1.6). As such nanodiamond particles, nanodiamond particles having a graphite phase obtained by an explosion method, and nanodiamond particles obtained by oxidizing the nanodiamond particles are preferable. Further, the fluorinated nanodiamond particles obtained by treating the nanodiamond particles with fluorine and the siliconized nanodiamond particles obtained by treating with silicon are suitable because they have excellent dispersibility in a polymer resin and are water repellent. It is especially effective for applications. The fluorinated nanodiamond particles having a median diameter of 100 to 400 nm preferably have a shape in which nanoparticles having a diameter of about 1 to 10 nm are aggregated.

Silica can also be used as the light-reflecting fine particles. As the silica, vapor phase silica, wet silica, and other amorphous synthetic silica can be used, and it is preferable to use vapor phase silica. Gas phase silica is also called a dry method as opposed to a wet method, and is generally produced by a flame hydrolysis method. Specifically, a method of burning silicon tetrachloride together with hydrogen and oxygen is generally known, but silanes such as methyltrichlorosilane and trichlorosilane can also be used alone or tetrachloride instead of silicon tetrachloride. It can be used in a mixed state with silicon. In addition, wet silica is further classified into sedimentation silica, gel silica, and sol silica depending on the production method. Sedimentation method Silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions, and the silica particles that have grown particles are aggregated and settled, and then commercialized through the steps of filtration, washing with water, drying, crushing and classification.

Organic fine particles can also be used as the light-reflecting fine particles. Examples of the organic fine particles include acrylic polymer, styrene-acrylic copolymer, vinyl acetate-acrylic copolymer, vinyl acetate polymer, ethylene-vinyl acetate copolymer, chlorinated polyolefin polymer, ethylene-vinyl acetate-acrylic and the like. Multi-polymer, SBR, NBR, MBR, carboxylated SBR, carboxylated NBR, carboxylated MBR, polyvinyl chloride, polyvinylidene chloride, polyester, polyolefin, polyurethane, polymethacrylate, polytetrafluoroethylene, polymethylmethacrylate , Polycarbonate, polyvinyl acetal resin, rosin ester resin, episulfide resin, epoxy resin, silicone resin, silicone-acrylic resin, melamine resin and other known resins can be used.

Hollow beads can also be used as the light-reflecting fine particles. Hollow beads are resin particles in which gases such as air, oxygen, and nitrogen are trapped inside a transparent resin. As the transparent resin, the same resin as the organic fine particles can be used.

The content of the light-reflecting fine particles in the light-scattering layer can be appropriately adjusted according to the shape of the light-reflecting fine particles, the specular reflectance, and the like. For example, the content of the light-reflecting fine particles is preferably 0.0001 to 5.0% by mass, preferably 0.0005 to 3.0% by mass, and more preferably 0.001 with respect to the binder. ~ 2.0% by mass. By dispersing light-reflecting fine particles in a binder at a low concentration as in the above range to form a light scattering layer, the projected light emitted from a light source is diffusely scattered and reflected, so that the projected light can be visually recognized. It is possible to improve the property and the visibility of the transmitted light.

(Magnetic fine particles)
The type of the magnetic fine particles is not particularly limited as long as it is oriented at an arbitrary angle in the binder by applying a magnetic field. The method of applying the magnetic field is not particularly limited, and a conventionally known method can be used. For example, by molding a dispersion containing a binder and magnetic fine particles into a film and applying a magnetic field in the thickness direction of the film by an arbitrary method, the magnetic fine particles in the film can be arranged along the lines of magnetic force. At that time, the orientation state is controlled by controlling the direction and position of the magnetic field lines passing through the film by changing the conditions such as the direction and strength of application of the magnetic field, the position and transport speed of the film in the manufacturing process, and the like. Is also possible. Subsequently, the film is cured in a state where the magnetic fine particles are oriented at a desired angle to fix the orientation state of the magnetic fine particles, whereby a film in which the orientation state of the magnetic fine particles is controlled can be obtained. In order to prevent the orientation state from being relaxed between the orientation and immobilization of the magnetic particles, the viscosity of the dispersion is determined by the film molding method, the strength of the magnetic field, and from the orientation to the immobilization. It is desirable to adjust appropriately according to the time.

In the present invention, the magnetic fine particles oriented in the binder by the application of a magnetic field are considered to be periodically oriented while forming a chain cluster because the magnetic fine particles themselves also have magnetic force and attract each other. For example, it is preferable that the chain cluster of magnetic fine particles forms a structure in which a plurality of magnetic fine particles are connected in a bead, and the magnetic fine particles are arranged substantially in parallel at substantially equal intervals. The length of the chain clusters of the magnetic fine particles can be appropriately adjusted according to the thickness of the light scattering layer, and is, for example, preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferable. Is 1 μm or more, more preferably 5 μm or more, preferably 1 mm or less, more preferably 500 μm or less, still more preferably 100 μm or less, still more preferably 50 μm or less. When the length of the chain clusters of the magnetic fine particles is about the above range, the effect of light reflection control can be further exerted. The length of the chain clusters of the magnetic fine particles can be measured based on an image obtained by measuring a cross section of the light scattering layer in the thickness direction using a scanning electron microscope (for example, Phoenix ProX manufactured by Phoenix-world).

The orientation angle of the magnetic fine particles in the light scattering layer is not particularly limited and can be set as appropriate. For example, an appropriate angle according to the projection angle of the projector may be used, but it is preferably 20 degrees or more and 90 degrees or less, more preferably 30 degrees or more and 80 degrees or less, and further preferably 40 degrees or more and 70 degrees or less. Is. The orientation angle of the magnetic fine particles can be adjusted to any angle depending on the conditions of application of the magnetic field. The orientation angle of the magnetic fine particles can be measured based on an image obtained by measuring a cross section of the light scattering layer in the thickness direction using a scanning electron microscope (for example, Phenom ProX manufactured by Phoenix-world).

Examples of the magnetic fine particles include fine particles made of iron, nickel, cobalt, alloys containing these metals, and the like. Examples of the alloy include iron-nickel alloy, iron-cobalt alloy, iron-chromium alloy, iron-silicon alloy, cobalt-chromium alloy, cobalt-titanium oxide alloy and the like. These magnetic fine particles may be used alone or in combination of two or more. For example, magnetic fine particles obtained by mixing or laminating two or more of these can be used. These magnetic fine particles may be coated with an inorganic material (excluding the above-mentioned metals and alloys) other than the magnetic particles in order to impart functionality such as color tone adjustment, reflectance control, and corrosion resistance. In the present invention, it is preferable to use magnetic fine particles in which both sides (surface) of the magnetic fine particles are coated with an inorganic material other than the magnetic particles to provide a functional layer. For example, the light reflectivity may be enhanced by coating the magnetic fine particles with a metal such as aluminum, silver, platinum, and gold, or a metal oxide such as titanium oxide and zirconium oxide, or by coating with silica or the like. May suppress surface deterioration. The magnetic fine particles provided with such a functional layer preferably have a multi-layer structure, more preferably a structure of three or more layers, for example, Al / Ni / Al, Al / Fe / Al, Al / Co / Al. , SiO ₂ / X (magnetic fine particles) / SiO _{2 and the} like. Further, the functional layers on both sides (surface) of the magnetic fine particles may be colored.

The shape of the magnetic fine particles is not particularly limited, but is preferably flaky or flat in order to enhance light reflectivity and exhibit clearer anisotropy. The average diameter of the primary particles of the magnetic fine particles is preferably 0.01 μm or more, more preferably 0.1 μm or more, still more preferably 0.5 μm or more, still more preferably 1 μm or more. Further, it is preferably 5.0 μm or less, more preferably 4.0 μm or less, and further preferably 3.0 μm or less. Further, the magnetic fine particles have an average aspect ratio (= average diameter / average thickness of the magnetic fine particles) of preferably 2 or more, more preferably 3 or more, still more preferably 5 or more, and preferably 300. It is less than or equal to, more preferably 200 or less, still more preferably 100 or less. When the average diameter and the average aspect ratio of the magnetic fine particles are within the above ranges, a sufficient scattering effect of 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 average diameter of the magnetic fine particles can be measured by using a laser diffraction type particle size distribution measuring device (MT3200II manufactured by Microtrac Bell) if the particles are simple substances or dispersions. The particle size in the film can be determined by observing the cross section with a scanning electron microscope. Moreover, the average aspect ratio can be calculated from a scanning electron microscope image.

The content of the magnetic fine particles in the light scattering layer can be appropriately adjusted according to the type of the magnetic fine particles and the transmitted light intensity, and is preferably 0.01% by mass or more, more preferably 0, with respect to the binder. .1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, and preferably 10% by mass or less, more preferably 7.0. It is 0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less. The light reflectivity can be improved by orienting the magnetic fine particles in the binder at a concentration in the above range to form a light scattering layer. For example, the visibility of the video light can be improved by sufficiently scattering and reflecting the video light projected from the projector.

(Additive)
A conventionally known additive may be added to the light scattering layer in addition to the above-mentioned light-reflecting material, depending on the intended use. Examples of the additive include a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a mold release agent, a flame retardant, a plasticizer, a lubricant, a coloring material, a fluorescent material, and a brightness improving material. Can be mentioned. As the coloring material, dyes or dyes such as carbon black, graphite, azo dyes, anthraquinone dyes, and perinone dyes can be used. By including a coloring material (carbon black, graphite particles, etc.), it is possible to improve the degree of freedom in setting the total light transmittance and the haze of the light scattering layer and the transparent screen provided with the light scattering layer. Further, the color may be adjusted by mixing the coloring materials. Further, the brightness improving material is composed of aluminum, silver, copper, platinum, gold, titanium, nickel, tin, tin-cobalt alloy, indium, chromium, titanium oxide, aluminum oxide, zirconium oxide, zinc oxide, and zinc sulfide. Metal-based particles, a glittering material in which glass is coated with a metal or a metal oxide, or a glittering material in which a natural mica or a synthetic mica is coated with a metal oxide may be added. The brightness of the image light can be improved by adding the brightness improving material. Further, a liquid crystal compound or the like may be mixed.

(Base layer)
The base material layer is a layer for supporting the above-mentioned light scattering 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 and the desired optical properties. As such a resin, for example, a highly transparent resin similar to the above-mentioned light scattering layer can be used. Further, a composite film or sheet in which two or more kinds of the above resins are laminated may be used. The thickness of the base material layer can be appropriately changed depending on the material so that its strength becomes appropriate, and may be in the range of, for example, 10 to 1000 μm.

(Protective layer)
The protective layer is laminated on the surface side (the side that comes into contact with the atmosphere) 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 material that does not impair the transparent visibility of the transparent screen and the desired optical properties. As such a material, for example, a resin that is cured by ultraviolet rays or electron beams, that is, an ionizing radiation curable resin, an ionizing radiation curable resin mixed with a thermoplastic resin and a solvent, and a thermosetting resin are used. Of 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 polyester resin having a relatively low molecular weight, a polyether resin, an acrylic resin, an epoxy resin, a urethane resin, or an alkyd resin. Oligos or prepolymers such as (meth) alrelate of polyfunctional compounds such as spiroacetal resin, polybutagen resin, polythiolpolyene resin, polyhydric alcohol, and ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene as reactive diluents, Monofunctional and polyfunctional monomers such as methylstyrene and N-vinylpyrrolidone, such as polymethylol propanetri (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 and the like can be used in a relatively large amount. ..

In order to obtain the ionizing radiation curable resin composition into an ultraviolet curable resin composition, acetophenones, benzophenones, Michler benzoylbenzoates, α-amyloxime esters, and tetramethylchurammono are used as photopolymerization initiators in the composition. Sulfide, thioxanthones, n-butylamine, triethylamine, poly-n-butylhosophine and the like can be mixed and used as a photosensitizer. In particular, in the present invention, it is preferable to mix urethane acrylate as the oligomer, dipentaerythritol hexa (meth) acrylate or the like as the monomer.

As a method for curing the ionizing radiation curable resin composition, the method for curing the ionizing radiation curable resin composition can be a normal curing method, that is, curing by 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 cockloft Walton type, bandegraph type, resonance transformer type, insulated core transformer type, linear type, dynamitron type, and high frequency type. An electron beam having an energy of 1000 KeV, preferably 100 to 300 KeV is used, and in the case of ultraviolet curing, ultraviolet rays emitted from light rays such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, and a metal halide lamp are emitted. Available.

As the protective layer, a method such as spin coating, die coating, dip coating, bar coating, flow coating, roll coating, gravure coating or the like is applied on the light scattering layer with the coating liquid of the ionizing radiation (ultraviolet) ray curable resin composition. Then, it can be formed by applying it to the surface of the light scattering layer and curing the coating liquid by the means as described above. Further, the surface of the protective layer may be provided with a fine structure such as an uneven structure, a prism structure, or a microlens structure, depending on the purpose.

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

The acrylic resin pressure-sensitive adhesive is polymerized by containing at least a (meth) acrylic acid alkyl ester monomer. 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. The (meth) acrylic acid refers to acrylic acid and / or methacrylic acid. Examples of (meth) acrylic acid alkyl ester monomers include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, n-propyl (meth) acrylic acid, sec-propyl (meth) acrylic acid, 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) acrylate Examples thereof include n-octyl, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, undecyl (meth) acrylate, and lauryl (meth) acrylate. Further, the (meth) acrylic acid alkyl ester is usually copolymerized in an acrylic pressure-sensitive adhesive at a ratio of 30 to 99.5 parts by mass.

Commercially available adhesives may be used, for example, SK Dyne 2094, SK Dyne 2147, SK Dyne 1811L, SK Dyne 1442, SK Dyne 1435, and SK Dyne 1415 (all manufactured by Soken Kagaku Co., Ltd.). Oliverine EG-655, Oliverine BPS5896 (above, manufactured by Toyo Ink Co., Ltd.) and the like (above, trade name) can be preferably used.

(Anti-reflective layer)
The antireflection layer is a layer for preventing reflection on the outermost surface of the transparent screen or the transparent viewing angle control film and reflection from external light. The antireflection layer may be laminated on the surface side (atmosphere side) of the transparent screen or the transparent viewing angle control film, or may be laminated on both sides. Especially when it is used as a transparent screen, it is preferable to stack it on the observer side. The antireflection layer is preferably formed by using a material that does not impair the transmission visibility and desired optical characteristics of the transparent screen or the transparent viewing angle control film. As such a material, for example, a thin film of an inorganic compound such as magnesium fluoride or silicon dioxide or a low refractive index material such as fluorine-bearing can be used. Further, the surface of the antireflection layer may be provided with a fine structure such as an uneven 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 laminating a coating film, a method of dry-coating the film substrate by direct vapor deposition or sputtering, gravure coating, microgravure coating, bar coating, slide die. Methods such as coating, slot die coating, and wet coating such as dip coating can be used.

(Functional layer)
In addition to the above-mentioned layers, the transparent screen may include various conventionally known functional 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 blocking layer such as ultraviolet rays and infrared rays. Be done.

(Manufacturing method of transparent screen)
The method for manufacturing a transparent screen includes a step of forming a light scattering layer.

An example of a step of forming a light scattering layer when light-reflecting fine particles are used as a light-reflecting material will be described. For example, a light scattering layer containing light-reflecting fine particles includes an extrusion molding method consisting of a kneading process and a film forming process, a cast film forming method, a gravure coating, a micro gravure coating, a bar coating, and a slide die coating. It can be molded by known methods such as slot die coating, dip coating, coating method including spray method, injection molding method, calendar molding method, blow molding method, compression molding method, cell casting method, etc. Extrusion molding method, injection molding The method and the coating method can be preferably used. More specifically, the light scattering layer can be formed by the following steps (1) to (3).
(1) The above-mentioned light-reflecting fine particles and the above-mentioned binder are kneaded to obtain a resin composition.
(2) The obtained resin composition is supplied to a melt extruder heated to a temperature equal to or higher than the melting point (Tm to Tm + 70 ° C.) to melt the resin composition.
(3) The melted resin composition is extruded into a sheet by a die such as a T die, and the extruded sheet is rapidly cooled and solidified by a rotating cooling drum or the like to form a film.

An example of a step of forming a light scattering layer when magnetic fine particles are used as a light-reflecting material will be described. For example, the light scattering layer containing magnetic fine particles can be formed by the following steps (1) to (4).
(1) The above-mentioned magnetic fine particles are dispersed in the above-mentioned binder to obtain a dispersion. The dispersion method is not particularly limited, and a conventionally known dispersion method can be used. For example, as the binder, it is preferable to use a UV curable resin from the viewpoint of process control and dispersion / orientation of magnetic fine particles.
(2) The obtained dispersion is molded. For example, the dispersion is applied onto a film serving as a base material layer or a support, and if necessary, the dispersion is pre-cured by heating or the like to form a coating film and then molded.
(3) A magnetic field is applied to the molded dispersion to orient the magnetic fine particles at an arbitrary angle. By adjusting the strength of the magnetic field and the application method, the orientation angle of the magnetic fine particles can be adjusted.
(4) The dispersion in which the magnetic fine particles are oriented is cured to fix the orientation state of the magnetic fine particles to form a light scattering layer. For example, when a UV curable resin is used as the binder, the dispersion can be cured by UV irradiation.

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 light scattering layer obtained above. The method of laminating each layer is not particularly limited, and a conventionally known method can be used. When each layer is laminated by dry lamination, an adhesive or the like may be used as long as the transparent visibility of the transparent screen and the desired optical characteristics are not impaired.

<Transparent viewing angle control film>
As the transparent viewing angle control film used in the image projection system, a conventionally known transparent viewing angle control film can be used, and incident light is scattered within the range of the viewing angle control angle, and outside the range of the viewing angle control angle. Anything that is transparent will do. The viewing angle control angle can be defined by an angle formed with respect to an orthogonal plane (perpendicular line) in the thickness direction of the transparent viewing angle control film with the surface (interface) on the transparent screen side of the transparent viewing angle control film as a base point. The viewing angle control angle is preferably 10 degrees or more and 80 degrees or less, more preferably 15 degrees or more and 70 degrees or less, and further preferably 20 degrees or more and 60 degrees or less. Further, the transparent viewing angle control film has a parallel light transmittance within the range of the viewing angle control angle, preferably 0% or more and less than 40%, more preferably 0% or more and less than 30%, and the viewing angle control angle. The parallel light transmittance outside the range is preferably 60% or more and 92% or less, and more preferably 70% or more and 92% or less.

As such a viewing angle control film, a louver structure as described in Patent Documents 4 and 5 obtained by alternately laminating a single-layer colored or opaque film and a transparent film and cutting in the laminating direction is used. It may be a film.

Further, it may be a light ray control film as described in Patent Document 6, which has a large number of grooves on the film surface and is composed of a transparent film in which the inside of the grooves is filled with an absorbent material.

In the film or light ray control film using the above louver structure, the viewing angle control range can be adjusted by the distance between the light-shielding portions and the length of the light-shielding portions in the film thickness direction. In addition, the front transmittance is determined by the area ratio occupied by the transmissive part, but in order to obtain sufficient light-shielding performance in the light-shielding part, it is necessary to increase the area ratio of the light-shielding part, so that the front transmittance decreases, and the light-shielding performance It has the characteristic that the front transmittances are contradictory.

Further, the transparent viewing angle control film is an optical control plate as described in Patent Document 7, which has a function of scattering incident light in a predetermined angle range by using two or more types of photopolymerizable resins having different refractive indexes. You may. According to Patent Document 7, a resin composition composed of photopolymerizable oligomers and monomers having different refractive indexes or a mixture thereof is maintained in a film shape, and is cured by irradiating it with ultraviolet rays from a specific direction. , An optical control film having a function of scattering only a predetermined range of light can be obtained. The obtained film exhibits anisotropy with respect to the major axis direction and the minor axis direction of the ultraviolet light source, and emits light in a predetermined angle range only when the cured film-like product is rotated about the major axis direction of the light source. Scatter. That is, the obtained films exist in a state in which regions having different refractive indexes are oriented in a certain direction, and light incident from a predetermined angle range is repeatedly scattered at the boundary between regions having different refractive indexes to control the viewing angle. It is considered that the effect can be obtained. In this method, the two or more types of photopolymerizable resins used have different refractive indexes but are transparent without absorption, so that a very high front transmittance can be obtained, and ultraviolet light is incident during curing. Since it is almost completely transparent in the direction, it is particularly suitable as the transparent viewing angle control film in the present invention.

As the transparent viewing angle control film, a commercially available transparent viewing angle control film can be used. For example, Wincos Vision Control Film (Y-2555) manufactured by Lintec Co., Ltd. (viewing angle control angle: 25 degrees or more and 55 degrees or less). Can be used.

<Laminated body>
The laminate used in the image projection system includes a transparent screen and a transparent viewing angle control film. The laminate may have a form in which a transparent screen is directly formed on the viewing angle control film, or a form in which the viewing angle control film is directly formed on the transparent screen.

The laminate may include a transparent layer containing a transparent resin, preferably between the transparent screen and the viewing angle control film, as long as the performance of the image projection system is not impaired. For example, the laminate may be in the form of a transparent screen and a viewing angle control film bonded together with an adhesive, an adhesive, an adhesive resin, or the like.

The laminated body has a parallel light transmittance outside the viewing angle control angle range of preferably 60% or more and 98% or less, more preferably 65% or more and 96% or less, and further preferably 70% or more and 94% or less. It is even more preferably 75% or more and 92% or less. When the parallel light transmittance of the transparent screen is within the above range, the transparency is high and the transmission visibility can be further improved. In the present invention, the parallel light transmittance of the transparent screen can be measured in accordance with JIS K 7136 and JIS K 7361 using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., product number: SH-7000). it can.

The laminate has a mapping property of preferably 65% or more, more preferably 70% or more and 98% or less, still more preferably 75% or more and 97% or less, and even more preferably 80% or more and 96% or less. Is. If the image quality of the transparent screen is within the above range, the image seen through the transparent screen becomes extremely clear. In the present invention, the mapability is a value of image sharpness (%) when measured with an optical comb width of 0.125 mm in accordance with JIS K 7374.

<Vehicle parts>
In the image projection system of the present invention, a vehicle member provided with the above-mentioned transparent screen may be used. Examples of vehicle members include windshields and side glasses. By providing the above-mentioned transparent screen on the vehicle member, a clear image can be displayed on the vehicle member without providing a separate screen.

<Building materials>
In the image projection system of the present invention, a building member provided with the above-mentioned transparent screen may be used. Examples of building members include windowpanes of houses, glass walls of convenience stores and roadside stores, and the like. By providing the above-mentioned transparent screen on the building member, a clear image can be displayed on the building member without providing a separate screen.

<Characteristic evaluation of transparent screen>
The measurement method of the transparent screen is as follows.
(1) Measurement was performed in accordance with JIS K 7136 using a haze haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., product number: SH-7000).
(2) Measurement was performed in accordance with JIS K 7361 using a total light transmittance haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., product number: SH-7000).
(3) Reproducibility Image sharpness when measured with an optical comb width of 0.125 mm in accordance with JIS K 7374 using a reproducibility measuring device (manufactured by Suga Test Instruments Co., Ltd., product number: ICM-1T). The value of%) was defined as the mapping property. The larger the image sharpness value, the higher the transmission mapping property.
(4) Length of chain clusters In the light scattering layer, based on an image obtained by measuring a cross section in the thickness direction of a transparent screen (light scattering layer) using a scanning electron microscope (Phenom ProX manufactured by Phoenix-world). The length of the chain cluster formed by the magnetic fine particles was measured.
(5) Orientation angle Orientation of magnetic fine particles in the light scattering layer based on an image obtained by measuring a cross section in the thickness direction of a transparent screen (light scattering layer) using a scanning electron microscope (Phenom ProX manufactured by Phoenix-world). The angle (the angle formed with respect to the normal direction in the thickness direction of the light scattering layer surface) was measured.

<Making a transparent screen>
[Manufacturing Example 1]
First, polyethylene terephthalate (PET) pellets (manufactured by Bell Polyester Co., Ltd., brand IFG8L) and flaky aluminum fine particles A (light-reflecting fine particles, average diameter of primary particles 1 μm) of 0.012% by mass based on PET pellets. Aspect ratio of 300 and specular reflectance of 62.8%) were mixed in a tumbler mixer for 30 minutes to obtain PET pellets in which flaky aluminum was 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. The obtained masterbatch and PET pellets (brand IFG8L) are uniformly mixed at a ratio of 1: 2, then put into a hopper of a twin-screw extruder equipped with a T-die, extruded at an extrusion temperature of 250 ° C., and thickened. A 75 μm film was formed to obtain a transparent screen 1.

When the optical characteristics of the transparent screen 1 were measured by the above method, the haze value was 3.9%, the total light transmittance was 86%, and the reproducibility was 88%.

[Manufacturing Example 2]
Al / Ni / Al (thickness 20 nm / 20 nm / 20 nm) laminated thin film formed by vacuum deposition was pulverized to obtain flaky magnetic fine particles (average diameter of primary particles: 1.7 μm, aspect ratio: 28). .. A commercially available UV curable resin (polymer acrylate type) was used as a binder, and 1.2% by mass of the obtained magnetic fine particles were added to the weight of the solid content in the UV curable resin to obtain a dispersion liquid. The obtained dispersion was applied onto an A5 version PET film (Biaxially stretched PET film manufactured by Toyobo Co., Ltd., Cosmo Shine A4300, thickness 50 μm) using a bar coater (Table Coater Model TC-3 manufactured by Mitsui Electric Co., Ltd.). After coating, a coating film (thickness 5 μm) was formed and molded, a magnetic field was applied by passing it through a 300 mT electromagnet. By irradiating UV immediately after applying the magnetic field, a transparent screen 2 having a light scattering layer in which magnetic fine particles were oriented at a specific angle was obtained.

When the optical characteristics of the transparent screen 2 were measured by the above method, the haze value was 11%, the total light transmittance was 76%, and the reproducibility was 79%.

Further, as a result of observing the cross section of the transparent screen 2 in the thickness direction with a digital microscope and a scanning electron microscope, the magnetic fine particles were not uniformly dispersed and were oriented while forming chain clusters. The length of the chain cluster measured by the above method was in the range of 5.5 to 12.5 μm, and the average value was 9.0 μm. When the orientation angle of the chain cluster was measured by the above method, it was 42 degrees.

<Preparation of viewing angle control film>
As a transparent viewing angle control film, a Wincos Vision Control Film (Y-2555) manufactured by Lintec Corporation (viewing angle control angle: 25 degrees or more and 55 degrees or less) was prepared.

<Making a video projection system>
[Example 1]
The image projection system 1 was produced in the same manner as in the embodiment shown in FIG. Specifically, the transparent screen 1 obtained above was placed on a table, and the transparent viewing angle control film was placed on the front side (observer side) of the transparent screen at a distance of 20 cm. Further, the image projection unit (WX450ST manufactured by Canon Inc.) was arranged by adjusting the reflection angle of the image light on the surface of the transparent screen so as to be within the range of the viewing angle control angle of the transparent viewing angle control film. When the image light was projected onto the transparent screen from diagonally above the transparent viewing angle control film, a clear image was formed on the transparent screen, and the reflected light did not cause an unnecessary image formation on the table. The result of photography is shown in FIG.

[Example 2]
The image projection system 2 was produced in the same manner as in the embodiment shown in FIG. Specifically, the transparent screen 1 obtained above was placed on a table, and the transparent viewing angle control film was placed close to the front side (observer side) of the transparent screen. Further, the image projection unit (WX450ST manufactured by Canon Inc.) was arranged by adjusting the reflection angle of the image light on the surface of the transparent screen so as to be within the range of the viewing angle control angle of the transparent viewing angle control film. When the image light was projected onto the transparent screen from diagonally above the transparent viewing angle control film, a clear image was formed on the transparent screen, and the reflected light did not cause an unnecessary image formation on the table.

[Example 3]
An image projection system 3 was produced in the same manner as in Example 1 except that the transparent screen 2 was used instead of the transparent screen 1. When the image light was projected onto the transparent screen from diagonally above the transparent viewing angle control film, a clear image was formed on the transparent screen, and the reflected light did not cause an unnecessary image formation on the table.

[Example 4]
The image projection system 4 was produced in the same manner as in Example 2 except that the transparent screen 2 was used instead of the transparent screen 1. When the image light was projected onto the transparent screen from diagonally above the transparent viewing angle control film, a clear image was formed on the transparent screen, and the reflected light did not cause an unnecessary image formation on the table.

[Comparative Example 1]
The transparent screen 1 obtained above was placed on the table. When the image light was projected onto the transparent screen from diagonally above the transparent screen, a clear image was formed on the transparent screen, and the reflected light formed an unnecessary image on the table. Since the transparent viewing angle control film was not placed, the reflection of the image on the table hindered comfortable viewing. The result of photography is shown in FIG.

11, 21, 31: Transparent screen 12, 22, 32: Transparent viewing angle control film 13, 23, 33: Image projection unit 14, 24, 34: Range of projection angle of image light 15, 25, 35: Image light 16 , 26, 36: Reflected light 17, 27, 37: Range of viewing angle control angle 18, 28, 38: Observer 19, 29, 39: Orthogonal plane (vertical line) of transparent screen
20, 30: Floor 40: Ceiling α: Angle formed by reflected light with respect to the orthogonal plane (perpendicular line) of the transparent screen β: Angle formed with respect to the orthogonal plane (perpendicular line) of the transparent viewing angle control film (viewing angle limiting angle)
γ: The angle formed by the image light with respect to the orthogonal plane (perpendicular line) of the transparent screen (projection angle of the image light)

Claims (10)

An image projection system including a transparent screen, an image projection unit arranged on the front side of the transparent screen, and a transparent viewing angle control film arranged between the transparent screen and the image projection unit.
The image projection unit is arranged so that the reflection angle of the image light on the surface of the transparent screen on the transparent viewing angle control film side is within the range of the viewing angle control angle of the transparent viewing angle control film.
The image light projected from the image projection unit is imaged on the transparent screen.
An image projection system in which reflected light on the surface of the transparent screen on the transparent viewing angle control film side is scattered by the transparent viewing angle control film. The image projection system according to claim 1, wherein the upper limit value of the range of the projection angle of the image light of the image projection unit is within the range of the viewing angle control angle of the transparent viewing angle control film. The image projection system according to claim 1 or 2, wherein the viewing angle control angle of the transparent viewing angle control film is 10 degrees or more and 80 degrees or less. The transparent viewing angle control film has a parallel light transmission rate of 0% or more and less than 40% within the viewing angle control angle range, and a parallel light transmission rate of 60% or more and 92% outside the viewing angle control angle range. The image projection system according to any one of claims 1 to 3, which is as follows. The image projection system according to any one of claims 1 to 4, wherein the transparent screen and the transparent viewing angle control film form a laminated body. The image projection system according to claim 5, wherein the laminate includes a transparent layer between the transparent screen and the transparent viewing angle control film. The image projection system according to any one of claims 1 to 6, wherein the haze value of the transparent screen is 35% or less. The image projection system according to any one of claims 1 to 7, wherein the transparent screen includes a light-reflecting material. The image projection system according to any one of claims 1 to 8, wherein the transparent screen is at least a part of a vehicle member. The image projection system according to any one of claims 1 to 8, wherein the transparent screen is at least a part of a building member.