JP7134123B2 - video projection system - Google Patents

Description

The present invention relates to a video projection system comprising a transparent screen, a video 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 video projection unit.

2. Description of the Related Art Conventionally, in an image projection system, an image projection unit projects image light onto an image projection object such as a screen, and an observer generally observes the image. In recent years, there has been an increasing demand for projecting and displaying product information, advertisements, etc. on show windows in department stores, transparent partitions in event spaces, walls, etc., using such video projection systems. In order to meet such demands, transparent screens are sometimes attached to show windows, transparent partitions, walls, etc., but the image light projected from the image projection unit is not reflected on the surface of the transparent screen. The emitted light reaches the floor, the ground, or the ceiling on the front side (viewer side) and causes unnecessary image formation, which hinders comfortable viewing and interferes with performance.

To address the above problems, it has been proposed to use a reflective screen with a surface layer having a specific surface shape on the surface facing the image projection unit in order to minimize the reflection of images on the ceiling. (Patent Documents 1 and 2). However, the reflective screens described in Patent Literatures 1 and 2 are not transparent and lack visibility through the screen. Therefore, the reflective screens described in Patent Literatures 1 and 2 cannot be used in applications requiring transmissive visibility, such as show windows in 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 reflection of images on the floor, ground or ceiling on the front side.

JP 2013-130837 A JP 2014-71278 A JP-A-51-44186 JP-A-50-26885 JP-A-2-97904 Japanese Patent No. 2547417

The present inventors have found that when a transparent screen is used, reflection of image light on the front side floor, ground, or ceiling due to reflection on the surface is less than that of the reflective transparent screens described in Patent Documents 1 and 2. We have found a problem that is severe and interferes with comfortable viewing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical problems, and an object of the present invention is to provide a video projection system comprising a transparent screen and a video projection unit arranged in front of the transparent screen, in which video light from the video projection unit is projected. To provide a video projection system capable of suppressing unnecessary image formation on the floor, ground or ceiling by reflected light on the surface of the transparent screen while forming an image on the transparent screen.

In order to solve the above technical problems, the present inventors have made intensive studies and found that, in a video projection system comprising a transparent screen and a video projection unit arranged on the front side of the transparent screen, the transparent screen and the video projection unit By placing a 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. , 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,
A video projection system comprising a transparent screen, a video 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 video projection unit,
The image projection unit is arranged such that the reflection angle of the image light on the surface of the transparent screen on the side of the transparent viewing angle control film is within the range of the viewing angle control angle of the transparent viewing angle control film,
image light projected from the image projection unit forms an image on the transparent screen;
A video projection system is provided in which reflected light from the surface of the transparent screen on the side of the transparent viewing angle control film 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 projection angles 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 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 light transmittance of 0% or more and less than 40% within the viewing angle control angle range, and a parallel light transmittance outside the viewing angle control angle range. It is preferable that the transmittance is 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 constitute a laminate.

In the 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 transparent screen preferably has a haze value of 35% or less.

In the above aspect of the present invention, it is preferred 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 part of the vehicle member.

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

According to the present invention, in a video projection system comprising a transparent screen and a video 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 video 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 side is within the range of the viewing angle control angle of the transparent viewing angle control film, While the projected image light forms an image on the transparent screen, the reflected light from the surface of the transparent screen on the side of the transparent viewing angle control film is scattered by the transparent viewing angle control film, making the reflected light unnecessary on the floor, ground or ceiling. It is possible to suppress the occurrence of image formation (image reflection). According to such a video projection system, it is possible to prevent unnecessary image formation from interfering with comfortable visual recognition and interfering with presentation.

1 is a conceptual diagram showing a projection video system of a first embodiment according to the present invention; FIG. FIG. 5 is a conceptual diagram showing a projection video system of a modified example of the first embodiment according to the present invention; FIG. 5 is a conceptual diagram showing a projection video system of a second embodiment according to the present invention; 4 is a photograph showing a result of observation from the front side (observer side) of the transparent screen in the projection imaging system of Example 1. FIG. 5 is a photograph showing a result of observation from the front side (observer side) of the transparent screen in the projection imaging system of Comparative Example 1. FIG.

<Video projection system>
A video projection system according to the present invention comprises a transparent screen, a video 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 video projection unit, and The image projection unit is arranged so that the reflection angle of the image light from the projection unit is within the range of the viewing angle control angle of the transparent viewing angle control film. In such a video projection system, while the video light projected from the video projection unit forms an image on the transparent screen, the reflected light from the surface of the transparent screen on the side of the transparent viewing angle control film is reflected by the transparent viewing angle control film. By being scattered, it is possible to suppress the reflected light from causing unnecessary image formation on the floor, ground or ceiling. According to such a video projection system, it is possible to prevent unnecessary image formation from interfering with comfortable visual recognition and interfering with presentation.

In the present invention, the term “transparency” includes transparency to the extent that transparency visibility can be realized according to the application, and translucency is also included.
In the present invention, the “viewing angle control angle of the transparent viewing angle control film” refers to a perpendicular plane (perpendicular 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. ).
In the present invention, the “reflection angle of image light” refers to the angle of reflected light with respect to a plane (perpendicular) perpendicular to the thickness direction of the transparent screen, with the surface (interface) of the transparent screen on the side of the transparent viewing angle control film as a base point. Defined by angle.
In the present invention, the "projection angle of the image light" is defined by the angle formed by the image light with respect to the orthogonal plane (perpendicular) of the transparent screen with the image projection unit as the base point.
In the present invention, the term "front side" refers to the direction of the viewer-side display surface of the transparent screen.

FIG. 1 shows a conceptual diagram of a video projection system according to the first embodiment of the invention. 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 part of the image light 15 is reflected by 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 unwanted imaging 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 part of the reflected light 16 is It is easy to suppress unnecessary imaging on the floor 20 by being scattered by the transparent viewing angle control film 12 . 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 may be changed. The light may reach the transparent screen 11 after passing through the transparent viewing angle control film 12 by, for example, passing through the transparent viewing angle control film 12 .

FIG. 2 shows a conceptual diagram of a modified example of the video 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, but in FIG. 2, the transparent screen and the transparent viewing angle control film are adjacent to form a laminate. Specifically, the image projection system shown in FIG. and a viewing angle control film 22 . In the first embodiment, the image projection unit 23 projects the image light 25 onto the observer 28 from above. 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 part of the image light 25 is reflected by 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 unwanted imaging 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 part of the reflected light 26 is It is easy to suppress unnecessary imaging on the floor 30 by being scattered by the transparent viewing angle control film 22 . 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. For example, the light may reach the transparent screen 21 without passing through the transparent viewing angle control film 22 .

FIG. 3 shows a conceptual diagram of a video projection system according to a second embodiment of the invention. The image projection system shown in FIG. and In the second embodiment, the image projection unit 33 projects image light 35 from below onto 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 part of the image light 35 is reflected by 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 form unwanted images 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, part of the reflected light 36 is within the transparent viewing angle. It is easy to suppress unnecessary imaging on the ceiling 40 by being scattered by the control film 32 . 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 can be changed. For example, the light may reach the transparent screen 31 without passing through the transparent viewing angle control film 32 .

In the video 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 or close together as shown in FIGS. You may have 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 that they constitute a laminate. By forming a laminate of the transparent screen and the transparent viewing angle control film, it is possible to suppress interfacial reflection and unnecessary irregular reflection of image light at the air interface between the transparent screen and the transparent viewing angle control film, thereby further improving the contrast. . In addition, the use of a laminate facilitates the arrangement of the video projection system. In addition, by forming a laminate, the image light diffusely transmitted through the transparent viewing angle control film forms an image on the transparent screen before it dissipates, thereby obtaining a good image with less out-of-focus and less resolution deterioration.

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

<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 onto the transparent screen described below. For example, commercially available rear projectors and front projectors can be used. In particular, WX450ST manufactured by Canon Inc. having a lens shift function can be preferably used because 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.

<transparent screen>
Transparent screens used in image projection systems preferably comprise a light scattering layer comprising a binder and a light reflective material. The transparent screen may have a single-layer structure consisting only of a light-scattering layer, or may be a laminate having a multilayer structure further comprising other layers such as a protective layer, a base layer, an adhesive layer, and an antireflection layer. There may be. The transparent screen may also comprise a support such as glass or a transparent partition. The transparent screen can anisotropically diffuse and reflect the projection light emitted from the image projection unit, thereby achieving both visibility of the projection light and visibility of the transmitted light.

The transparent screen may be flat or curved. For example, the transparent screen can be suitably used for glass windows, head-up displays, wearable displays, and the like, and can be particularly suitably used as a transparent screen for short-focus projectors.

The haze value of the transparent screen is preferably 35% or less, more preferably 1% or more and 30% or less, and still more preferably 2% or more and 25% or less. Further, the transparent screen preferably has a total light transmittance of 60% or more, more preferably 65% or more and 98% or less, more preferably 70% or more and 96% or less, and still more preferably 75%. It is 94% or more, and more preferably 80% or more and 92% or less. If the haze value and the total light transmittance of the transparent screen are within the above ranges, the transparency is high and the transmission visibility can be further improved. In the present invention, the haze value and total light transmittance of the transparent screen are measured according to JIS K 7136 and JIS K 7361 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product number: SH-7000). can do.

The transparent screen preferably has an image clarity of 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 below. If the image clarity of the transparent screen is within the above range, the image seen through the transparent screen will be extremely clear. In the present invention, the image clarity is the value of image definition (%) 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 diffusely reflected within the light-scattering layer, and the light utilization efficiency can be improved.

Although the thickness of the light scattering layer is not particularly limited, it is preferably 0.1 μm to 20 mm, more preferably 0.2 μm to 15 mm, from the viewpoint of application, productivity, handling and transportability. and more preferably 1 μm to 10 mm. If the thickness of the light-scattering layer is within the above range, it is easy to maintain the strength of the screen. The light scattering layer may be a molded body obtained using an organic binder or an inorganic binder described below, or may be a coating film formed on a substrate 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 layers are laminated by coating or the like, or two or more light-scattering layers are bonded together with an adhesive or the like.

(Binder)
The light scattering layer preferably uses a highly transparent organic binder or inorganic binder in order to obtain a highly transparent film. As the highly transparent organic binder, resins such as thermoplastic resins, thermosetting resins, and self-crosslinking resins such as ionizing radiation-curable resins 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, epoxy resins, 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, fluorine-based resins, and the like.

As highly transparent thermoplastic resins, acrylic resins, polyester resins, polyolefin resins, cellulose resins, vinyl resins, polycarbonate resins, and polystyrene resins are preferably used, and polymethyl methacrylate resins, More preferably, 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 are used. These resins can be used singly or in combination of two or more.

Ionizing radiation-curable resins with high transparency 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, polythiolpolyene resins, Oligomers or prepolymers such as (meth)arylates of polyfunctional compounds such as hydric alcohols, and monofunctional monomers such as ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, and N-vinylpyrrolidone as reactive diluents. and 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 Those containing relatively large amounts of hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentylglycol di(meth)acrylate and the like are preferred. Also, the ionizing radiation-curable resin may be a mixture of a thermoplastic resin and a solvent. As the ionizing radiation curable resin, a commercially available product can be used. For example, a urethane acrylate UV curable resin (trade name: Unidic V-4025) manufactured by DIC Corporation can be used.

Thermosetting resins with high transparency include phenol resins, epoxy resins, silicone resins, melamine resins, urethane resins, and urea resins. Among these, epoxy-based resins and silicone-based resins are preferred.

Examples of highly transparent inorganic binders include water glass, glass materials having a low softening point, and sol-gel materials. Water glass refers to a concentrated aqueous solution of alkali silicate, which usually contains sodium as an alkali metal. A representative water glass can be represented by Na ₂ O.nSiO ₂ (n: any positive number), and commercially available sodium silicate manufactured by Fuji Chemical Co., Ltd. can be used.

The glass material having a low softening point is a glass with a softening temperature preferably in the range of 150-620°C, more preferably in the range of 200-600°C, most preferably in the range of 250-550°C. °C range. Examples of such glass materials include PbO—B ₂ O ₃ based, PbO—B ₂ O ₃ —SiO ₂ based, PbO—ZnO—B ₂ O ₃ based, and mixtures containing acid components and metal chlorides. A lead-free low softening point glass obtained by the above can be mentioned. A low softening point glass material may be mixed with a solvent, a high boiling point organic solvent, or the like, in order to improve the dispersibility and formability of fine particles.

A sol-gel material is a group of compounds that undergo hydrolytic polycondensation and cure under the action of heat, light, a catalyst, or the like. For example, metal alkoxides (metal alcoholates), metal chelate compounds, metal halides, liquid glasses, spin-on glasses, or reaction products thereof containing a catalyst that promotes curing may be used. Also, 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 according to the required physical properties. A 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 chemically bonds with the surface of the inorganic substrate in the course of the polymerization reaction and strongly adheres to it. Therefore, by using a cured sol-gel material as the cured layer, a stable cured layer can be formed.

Metal alkoxides are a group of compounds obtained by reacting any metal species with water or an organic solvent using a hydrolysis catalyst or the like. It is a group of compounds in which a functional group such as a group is bonded. Metal species of metal alkoxides include silicon, titanium, aluminum, germanium, boron, zirconium, tungsten, sodium, potassium, lithium, magnesium, and tin.

For example, metal alkoxides whose metal species is silicon include dimethyldiethoxysilane, diphenyldiethoxysilane, phenyltriethoxysilane, methyltriethoxysilane (MTES), vinyltriethoxysilane, p-styryltriethoxysilane, methylphenyldisilane, 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-aminopropyltriethoxysilane silane, 3-aminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropyltriethoxysilane, triethoxysilane, diphenylsilanediol, dimethylsilanediol, and these A group of compounds in which the ethoxy group of the group of compounds is replaced with a methoxy group, a propyl group, an isopropyl group, a hydroxy group, and the like. Among these, triethoxysilane (TEOS) and tetramethoxysilane (TMOS) in which the ethoxy group of TEOS is replaced with a methoxy group are particularly preferred. These may be used alone, or may be used in combination of multiple types.

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

Specific examples of solvents include alcohols such as methanol, ethanol, isopropyl alcohol (IPA), n-propanol, butanol, 2-butanol, ethylene glycol and propylene glycol, hexane, heptane, octane, decane, cyclohexane and the like. Aliphatic hydrocarbons, aromatic hydrocarbons such as 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, ether alcohols such as butoxyethyl ether, hexyloxyethyl alcohol, methoxy-2-propanol, benzyloxyethanol, glycols such as ethylene glycol and propylene glycol, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether , propylene glycol monomethyl ether acetate, cellosolve, methyl cellosolve, ethyl cellosolve, carbitol, methyl carbitol, ethyl carbitol, butyl carbitol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol 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, phenols such as phenol and chlorophenol, N, amides such as N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; halogen solvents such as chloroform, methylene chloride, tetrachloroethane, monochlorobenzene and dichlorobenzene; heteroelement-containing compounds such as carbon disulfide; water, and mixed solvents thereof. The amount of the solvent to be added can be appropriately adjusted according to the types of the binder and fine particles, the viscosity range suitable for the manufacturing process described below, and the like.

(light reflective fine particles)
The shape of the light-reflecting fine particles is not particularly limited, and may be substantially spherical, flaky, or needle-like. When the shape of the light-reflective fine particles is substantially spherical, the median diameter of the primary particles is preferably 0.1 to 2,500 nm, more preferably 0.2 to 1,500 nm, and still more 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 scattering effect of projection light can be obtained without impairing transmission visibility, and a clear image can be projected on a transparent screen. . In the present invention, the median diameter (D ₅₀ ) of the primary particles of the light-reflecting fine particles is determined 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-reflective 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, even more preferably 0.1 to 50 μm, still more preferably 0 .5 to 30 μm. Furthermore, the light reflective fine particles have an average aspect ratio (= average diameter of the light reflective fine particles/average thickness) of preferably 3 to 800, more preferably 4 to 700, even more preferably 5 to 600, and even more preferably 10-500. When the average diameter and average aspect ratio of the light-reflecting fine particles are within the above ranges, it is possible to obtain a sufficient scattering effect of the projected light without impairing the transmission visibility, so that a clear image can be projected on the transparent screen. can. In the present invention, the average diameter of the light-reflecting fine particles was measured using a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation, product number: SALD-2300). The average aspect ratio was calculated from an SEM (manufactured by Hitachi High-Technologies Corporation, product name: SU-1500) 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 still more preferably 20.0% or more and 80.0% or less. In addition, in the present invention, the specular reflectance of the light-reflective fine particles is a value measured as follows.
(regular 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) was placed on a slide glass to a thickness of 0.5 mm or more. The specular reflectance of the coating film portion from the glass surface of the obtained glass plate with the coating film was measured.

Examples of light-reflecting fine particles include aluminum, silver, copper, platinum, gold, titanium, nickel, tin, tin-cobalt alloy, indium, chromium, titanium oxide, zinc oxide, Metallic particles consisting of tin oxide, zirconium oxide, cerium oxide, lead oxide, indium oxide, aluminum oxide, and zinc sulfide, lustrous materials in which metals or metal oxides are coated on glass, or metal oxides on natural or synthetic mica It is possible to use a glitter material coated with an object. 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 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 are excellent in light scattering ability. As a result, since the effect is exhibited with a small addition amount, it is possible to suppress multiple scattering, etc., which is one of the causes of clouding, and sufficient functions can be exhibited with a thickness of several μm to several tens of μm. The refractive index of nanodiamond particles is 2.4, which is higher than the refractive index of general resins (approximately 1.5 to 1.6). As such nanodiamond particles, nanodiamond particles having a graphite phase obtained by the bombardment method and nanodiamond particles obtained by oxidation treatment thereof are preferable. In addition, fluorinated nanodiamond particles obtained by treating nanodiamond particles with fluorine and siliconized nanodiamond particles obtained by treating with silicon are excellent in dispersibility in polymer resins and are suitable for water repellency. It is particularly effective for applications. The fluorinated nanodiamond particles having a median diameter of 100 to 400 nm are preferably in the form of aggregates of nanoparticles having a diameter of about 1 to 10 nm.

Silica can also be used as the light-reflecting fine particles. As silica, vapor-phase silica, wet-process silica, and other amorphous synthetic silica can be used, and vapor-phase silica is preferably used. Vapor-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 with hydrogen and oxygen is generally known. It can be used in a mixed state with silicon. Wet-process silica is further classified into precipitation-process silica, gel-process silica, and sol-process silica according to the manufacturing method. Precipitation silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions, and the grown silica particles are aggregated and sedimented, then filtered, washed with water, dried, pulverized, and classified into products.

Organic fine particles can also be used as the light-reflective fine particles. 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. SBR, NBR, MBR, carboxylated SBR, carboxylated NBR, carboxylated MBR, polyvinyl chloride, polyvinylidene chloride, polyester, polyolefin, polyurethane, polymethacrylate, polytetrafluoroethylene, polymethyl methacrylate , polycarbonate, polyvinyl acetal resins, rosin ester resins, episulfide resins, epoxy resins, silicone resins, silicone-acrylic resins, melamine resins, and other known resins.

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 confined inside a transparent resin. As the transparent resin, a resin similar to that for 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, regular reflectance, and the like. For example, the content of the light-reflective fine particles is preferably 0.0001 to 5.0% by mass, preferably 0.0005 to 3.0% by mass, more preferably 0.001, based on the binder. ~2.0% by mass. By dispersing the light-reflecting fine particles in the binder at a low concentration such as the above range to form a light-scattering layer, the projection light emitted from the light source is anisotropically scattered and reflected, thereby making the projection light visible. It is possible to improve the transparency and the visibility of transmitted light.

(Magnetic microparticles)
The type of magnetic fine particles is not particularly limited as long as they are oriented at any angle in the binder by application of a magnetic field. The method of applying the magnetic field is not particularly limited, and conventionally known methods can be used. For example, by forming 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 any method, the magnetic fine particles in the film can be aligned along the magnetic lines of force. At that time, by changing conditions such as the direction and strength of the magnetic field application, the position of the film in the manufacturing process and the transport speed, etc., the direction and position of the magnetic lines of force passing through the film can be controlled, thereby controlling the orientation state. is also possible. Subsequently, the film is cured with the magnetic fine particles oriented at a desired angle to fix the orientation state of the magnetic fine particles, thereby obtaining a film in which the orientation state of the magnetic fine particles is controlled. In order to avoid the relaxation of the orientation state during the period from orientation to fixation of the magnetic fine particles, the viscosity of the dispersion depends on the film forming method, the strength of the magnetic field, and the time from orientation to fixation. It is desirable to be adjusted appropriately according to time.

In the present invention, the magnetic fine particles oriented in the binder by application of a magnetic field are considered to be oriented periodically while forming chain-like clusters because the magnetic fine particles themselves also have magnetic force and attract each other. For example, it is preferable that a chain-like cluster of magnetic fine particles forms a structure in which a plurality of magnetic fine particles are strung together, and are arranged substantially parallel at substantially equal intervals. The length of chain-like clusters of magnetic fine particles can be appropriately adjusted according to the thickness of the light scattering layer. is 1 μm or more, still more preferably 5 μm or more, preferably 1 mm or less, more preferably 500 μm or less, even more preferably 100 μm or less, and even more preferably 50 μm or less. If the length of the chain-like cluster of the magnetic fine particles is within the above range, the effect of light reflection control can be further exhibited. The length of a chain cluster of 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 Phenom-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, preferably 20 degrees or more and 90 degrees or less, more preferably 30 degrees or more and 80 degrees or less, and still more preferably 40 degrees or more and 70 degrees or less. is. The orientation angle of the magnetic fine particles can be arbitrarily adjusted according to the conditions for applying a 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 Phenom-world).

Magnetic microparticles include, for example, microparticles made of iron, nickel, cobalt, and alloys containing these metals. Examples of such alloys include iron-nickel alloys, iron-cobalt alloys, iron-chromium alloys, iron-silicon alloys, cobalt-chromium alloys, cobalt-titanium oxide alloys, and the like. These magnetic fine particles can be used singly 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 other than the magnetic particles (excluding the above metals and alloys) 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 surfaces (surfaces) of the magnetic fine particles are coated with an inorganic material other than the magnetic particles to provide a functional layer. For example, the magnetic fine particles may be coated with metals such as aluminum, silver, platinum, and gold, or metal oxides such as titanium oxide and zirconium oxide to enhance light reflectivity, or may be coated with silica or the like. may suppress surface deterioration. Magnetic fine particles provided with such functional layers preferably have a multi-layered structure, more preferably a structure of three or more layers. , SiO ₂ /X (magnetic fine particles)/SiO ₂ . Moreover, the functional layers on both sides (surfaces) of the magnetic fine particles may be colored.

The shape of the magnetic fine particles is not particularly limited, but a flaky or flat shape is preferred in order to increase the light reflectivity and to develop a 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, and even more preferably 1 μm or more, Also, it is preferably 5.0 μm or less, more preferably 4.0 μm or less, and still more preferably 3.0 μm or less. Further, the magnetic fine particles preferably have an average aspect ratio (= average diameter of the magnetic fine particles/average thickness) of 2 or more, more preferably 3 or more, still more preferably 5 or more, and preferably 300. or less, more preferably 200 or less, and still more preferably 100 or less. When the average diameter and average aspect ratio of the magnetic fine particles are within the above ranges, a sufficient light scattering effect can be obtained without impairing transmission visibility, making it possible to project a clear image on a transparent screen. In the present invention, the average diameter of the magnetic fine particles can be measured using a laser diffraction particle size distribution analyzer (MT3200II manufactured by Microtrac Bell) in the case of single particles or dispersion liquid. The particle size in the film can be obtained from cross-sectional observation with a scanning electron microscope. Also, 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 intensity of the transmitted light. .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% by mass. % 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 within the above range to form the light scattering layer. For example, the visibility of the image light can be improved by sufficiently scattering and reflecting the image light projected from the projector.

(Additive)
In addition to the above-described light-reflecting materials, conventionally known additives may be added to the light-scattering layer depending on the application. Additives include, for example, dispersants, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, mold release agents, flame retardants, plasticizers, lubricants, colorants, fluorescent materials, and brightness enhancers. mentioned. As the coloring material, pigments or dyes such as carbon black, graphite, azo-based pigments, anthraquinone-based pigments, and perinone-based pigments 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 haze of the light scattering layer and the transparent screen provided therewith. Further, a coloring material may be mixed to adjust the tint. Furthermore, the brightness enhancement material consists 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. Metallic particles, glitter materials obtained by coating glass with metal or metal oxides, or glitter materials obtained by coating natural mica or synthetic mica with metal oxides may be added. Addition of a brightness enhancement material can improve the brightness of image light. Further, a liquid crystalline compound or the like may be mixed.

(Base material layer)
The substrate layer is a layer for supporting the light scattering layer, and can improve the strength of the transparent screen. The substrate layer is preferably formed using a highly transparent material such as glass or resin that does not impair the transmission visibility and desired optical properties of the transparent screen. As such a resin, for example, a highly transparent resin similar to that of the light scattering layer can be used. A composite film or sheet obtained by laminating two or more of the above resins may also be used. The thickness of the base material layer can be appropriately changed according to the material so that the strength thereof is appropriate, and may be in the range of 10 to 1000 μm, for example.

(protective layer)
The protective layer is laminated on the surface side (the side exposed to the atmosphere) of the transparent screen, and is a layer for imparting functions such as light resistance, scratch resistance, and antifouling properties. The protective layer is preferably formed using a material that does not impair the transmission visibility and desired optical properties of the transparent screen. Examples of such materials include resins that are cured by ultraviolet rays and electron beams, that is, ionizing radiation-curable resins, ionizing radiation-curable resins mixed with thermoplastic resins and solvents, and thermosetting resins. Of these, ionizing radiation-curable resins are particularly preferred.

The film-forming component of the ionizing radiation-curable resin composition preferably has 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, oligomers or prepolymers such as (meth)arylates of polyfunctional compounds such as polyhydric alcohols, and ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, as reactive diluents, Monofunctional monomers such as methylstyrene and N-vinylpyrrolidone as well as multifunctional 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. can be used in relatively large amounts. .

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

As a method for curing the ionizing radiation-curable resin composition, the ionizing radiation-curable resin composition can be cured by a normal curing method, that is, by irradiation with electron beams or ultraviolet rays. For example, in the case of electron beam curing, 50 ~ An electron beam or the like 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 beams such as ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arcs, xenon arcs and metal halide lamps are used. Available.

The protective layer is formed by spin coating, die coating, dip coating, bar coating, flow coating, roll coating, gravure coating, or the like with a coating solution of the ionizing radiation (ultraviolet) curable resin composition on the light scattering layer. can be formed by coating the surface of the light-scattering layer and curing the coating liquid by the above means. Further, the surface of the protective layer may be provided with a fine structure such as a concave-convex 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 the transparent screen. The adhesive layer is preferably formed using an adhesive composition that does not impair the transmission visibility and desired optical properties of the transparent screen. Examples of adhesive compositions include natural rubber-based, synthetic rubber-based, acrylic resin-based, polyvinyl ether resin-based, urethane resin-based, silicone resin-based, and the like. Specific examples of synthetic 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 silicone resins include dimethylpolysiloxane and the like. These adhesives can be used singly or in combination of two or more. Among these, acrylic pressure-sensitive adhesives are preferred.

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

A commercially available adhesive may be used, for example, SK Dyne 2094, SK Dyne 2147, SK Dyne 1811L, SK Dyne 1442, SK Dyne 1435, and SK Dyne 1415 (manufactured by Soken Chemical Co., Ltd.), Oribain EG-655, Oribain BPS5896 (manufactured by Toyo Ink Co., Ltd.) and the like (both trade names) can be preferably used.

(Antireflection layer)
The antireflection layer is a layer for preventing reflection from the outermost surface of the transparent screen or transparent viewing angle control film and reflection from outside 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. In particular, when used as a transparent screen, it is preferable to laminate on the viewer's side. The antireflection layer is preferably formed using a material that does not impair the transmission visibility and desired optical properties 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 material 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 may be lamination of a coating film, direct vapor deposition or dry coating on a film substrate by sputtering or the like, gravure coating, microgravure coating, bar coating, or slide die coating. Methods such as coating, slot die coating, and wet coating such as dip coating can be used.

(functional layer)
The transparent screen may include various conventionally known functional layers in addition to the layers described above. Examples of the functional layer include a light absorption layer containing a dye or a coloring agent, a light diffusion 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)
A method for manufacturing a transparent screen includes a step of forming a light scattering layer.

An example of the process of forming a light scattering layer in the case of using light reflective fine particles as the light reflective material will be described. For example, a light-scattering layer containing light-reflecting fine particles can be produced by extrusion molding, cast film-forming, gravure coating, micro-gravure coating, bar coating, slide die coating, It can be molded by known methods such as coating methods including slot die coating, dip coating, spraying, injection molding, calendar molding, blow molding, compression molding, cell casting, extrusion molding, injection molding. method and coating method can be suitably used. More specifically, the light scattering layer can be formed by the following steps (1) to (3).
(1) The above-described light-reflective fine particles and the above-described binder are kneaded to obtain a resin composition.
(2) The obtained resin composition is supplied to a melt extruder heated to a temperature (Tm to Tm+70° C.) above the melting point to melt the resin composition.
(3) The molten 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 to form a film.

An example of the process of forming the light scattering layer when magnetic fine particles are used as the light reflective material will be described. For example, a light scattering layer containing magnetic fine particles can be formed by the following steps (1) to (4).
(1) A dispersion is obtained by dispersing the above-described magnetic fine particles in the above-described binder. The dispersing method is not particularly limited, and conventionally known dispersing methods can be used. For example, it is preferable to use a UV curable resin as the binder from the viewpoint of process control and dispersion/orientation of the magnetic fine particles.
(2) Mold the resulting dispersion. For example, the dispersion is applied onto a base material layer or a film that serves as a support, and if necessary, the dispersion is precured by heating or the like to form a coating film, followed by molding.
(3) A magnetic field is applied to the molded dispersion to orient the magnetic fine particles at an arbitrary angle. The orientation angle of the magnetic fine particles can be adjusted by adjusting the strength of the magnetic field and the method of application.
(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 substrate layer, a protective layer, an adhesive layer, and the like on the light scattering layer obtained above. The lamination method of each layer is not particularly limited, and conventionally known methods can be used. When laminating each layer by dry lamination, an adhesive or the like may be used as long as it does not impair the transmission visibility of the transparent screen and the desired optical properties.

<Transparent viewing angle control film>
As the transparent viewing angle control film used in the video projection system, a conventionally known transparent viewing angle control film can be used. Any transparent material is acceptable. The viewing angle control angle can be defined by the angle formed with the surface (interface) of the transparent viewing angle control film on the transparent screen side as a base point with respect to the orthogonal plane (perpendicular line) in the thickness direction of the transparent viewing angle control film. 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 still more preferably 20 degrees or more and 60 degrees or less. In addition, the transparent viewing angle control film preferably has a parallel light transmittance of 0% or more and less than 40%, more preferably 0% or more and less than 30% within the viewing angle control angle range, and the viewing angle control angle is The parallel light transmittance outside the range is preferably 60% or more and 92% or less, more preferably 70% or more and 92% or less.

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

Further, it may be a light control film as described in Patent Document 6, which is composed of a transparent film having a number of grooves on the film surface and filling the inside of the grooves with a light-absorbing material.

In the film using the louver structure and the light beam control film described above, the viewing angle control range can be adjusted by the interval 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 portion, but in order to obtain sufficient light shielding performance in the light shielding portion, it is necessary to increase the area ratio of the light shielding portion. It has the characteristic that the front transmittance is contradictory.

Furthermore, as the transparent viewing angle control film, two or more kinds of photopolymerizable resins having different refractive indices are used, and a light control plate as described in Patent Document 7 having a function of scattering incident light within a predetermined angle range is used. can be According to Patent Document 7, a resin composition composed of a photopolymerizable oligomer or monomer having a difference in refractive index or a mixture thereof is maintained in the form of a film, which is irradiated with ultraviolet rays from a specific direction to be cured. , a light control film having a function of scattering light only in a predetermined range is obtained. The obtained film exhibits anisotropy with respect to the long axis direction and the short axis direction of the ultraviolet light source. scatter. In other words, the obtained film exists in a state in which regions with different refractive indices are oriented in a certain direction. It is considered that the effect can be obtained. In this method, the two or more types of photopolymerizable resins that are used differ only in their refractive index, and are transparent without absorption. It is particularly suitable as a transparent viewing angle control film in the present invention because it is almost completely transparent in all directions.

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 Corporation (viewing angle control angle: 25 degrees or more and 55 degrees or less). can be used.

<Laminate>
A laminate used in a video projection system comprises 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 a viewing angle control film, or a form in which a viewing angle control film is directly formed on a transparent screen.

The laminate may include a transparent layer, preferably containing a transparent resin, between the transparent screen and the viewing angle control film within a range that does not impair the performance of the image projection system. For example, the laminate may be in a form in which a transparent screen and a viewing angle control film are bonded together with an adhesive, an adhesive, an adhesive resin, or the like.

The laminate preferably has a parallel light transmittance outside the range of the viewing angle control angle of 60% or more and 98% or less, more preferably 65% or more and 96% or less, and still more preferably 70% or more and 94% or less. and more preferably 75% or more and 92% or less. If 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 according to JIS K 7136 and JIS K 7361 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product number: SH-7000). can.

The laminate preferably has an image clarity of 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 clarity of the transparent screen is within the above range, the image seen through the transparent screen will be extremely clear. In the present invention, the image clarity is the value of image definition (%) 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, the vehicle member having the transparent screen may be used. A windshield, a side glass, etc. are mentioned as a member for vehicles. By providing the vehicle member with the transparent screen, 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-described transparent screen may be used. Examples of building members include window glass of houses, glass walls of convenience stores and street shops, and the like. By providing the building member with the transparent screen, a clear image can be displayed on the building member without providing a separate screen.

<Characteristic evaluation of transparent screen>
The method for measuring the transparent screen is as follows.
(1) Haze Haze was measured according to JIS K 7136 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product number: SH-7000).
(2) Total light transmittance Measured according to JIS K 7361 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product number: SH-7000).
(3) Image clarity Using an image clarity measuring instrument (manufactured by Suga Test Instruments Co., Ltd., product number: ICM-1T), the image definition when measured with an optical comb width of 0.125 mm in accordance with JIS K 7374 ( %) was taken as the image clarity. A higher image definition value indicates a higher transmission clarity.
(4) Length of chain-like cluster Based on the image obtained by measuring the cross section of the transparent screen (light scattering layer) in the thickness direction using a scanning electron microscope (Phenom ProX manufactured by Phenom-world), the length of the chain cluster in the light scattering layer The length of chain-like clusters formed by magnetic fine particles was measured.
(5) Orientation angle The orientation of the magnetic fine particles in the light scattering layer is determined based on the image obtained by measuring the cross section of the transparent screen (light scattering layer) in the thickness direction using a scanning electron microscope (Phenom ProX manufactured by Phenom-world). The angle (the angle formed with respect to the normal direction of the thickness direction of the light scattering layer surface) was measured.

<Production of transparent screen>
[Production Example 1]
First, polyethylene terephthalate (PET) pellets (manufactured by Bell Polyester Co., Ltd., brand IFG8L) and 0.012% by mass of flaky aluminum fine particles A (light reflective fine particles, primary particle average diameter 1 μm, Aspect ratio 300, specular reflectance 62.8%) were mixed in a tumbler mixer for 30 minutes to obtain PET pellets having 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 masterbatch in which flaky aluminum was kneaded at an extrusion temperature of 250°C. After uniformly mixing the obtained masterbatch and PET pellets (brand IFG8L) at a ratio of 1: 2, it is put into a hopper of a twin screw extruder equipped with a T die and extruded at an extrusion temperature of 250 ° C. to obtain a thickness. A transparent screen 1 was obtained by forming a 75 μm film.

When the optical properties 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 image clarity was 88%.

[Production Example 2]
An Al/Ni/Al (thickness: 20 nm/20 nm/20 nm) laminated thin film formed by vacuum evaporation was pulverized to obtain flaky magnetic fine particles (average primary particle diameter: 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 solid weight in the UV curable resin to obtain a dispersion. The obtained dispersion is coated on an A5 PET film (biaxially oriented 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.). A magnetic field was applied by passing through an electromagnet of 300 mT after coating to form a coating film (5 μm thick) and molding. A transparent screen 2 having a light scattering layer in which magnetic fine particles are oriented at a specific angle was obtained by irradiating UV immediately after applying a magnetic field.

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

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

<Preparation of viewing angle control film>
As a transparent viewing angle control film, 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.

<Production of image projection system>
[Example 1]
A video 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. An image projection unit (WX450ST manufactured by Canon Inc.) was arranged so that the reflection angle of the image light on the surface of the transparent screen was adjusted to be within the range of the viewing angle control angle of the transparent viewing angle control film. When image light was projected onto the transparent screen from obliquely above the transparent viewing angle control film, a clear image was formed on the transparent screen, and the reflected light did not cause unnecessary image formation on the table. The results of photography are shown in FIG.

[Example 2]
A video 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. An image projection unit (WX450ST manufactured by Canon Inc.) was arranged so that the reflection angle of the image light on the surface of the transparent screen was adjusted to be within the range of the viewing angle control angle of the transparent viewing angle control film. When image light was projected onto the transparent screen from obliquely above the transparent viewing angle control film, a clear image was formed on the transparent screen, and the reflected light did not cause unnecessary image formation on the table.

[Example 3]
A video 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 image light was projected onto the transparent screen from obliquely above the transparent viewing angle control film, a clear image was formed on the transparent screen, and the reflected light did not cause unnecessary image formation on the table.

[Example 4]
A video 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 image light was projected onto the transparent screen from obliquely above the transparent viewing angle control film, a clear image was formed on the transparent screen, and the reflected light did not cause unnecessary image formation on the table.

[Comparative Example 1]
The transparent screen 1 obtained above was placed on the table. When image light was projected onto the transparent screen from obliquely above, a clear image was formed on the transparent screen, and the reflected light caused unwanted image formation on the table. By not using a transparent viewing angle control film, the reflection of the image on the table interfered with comfortable viewing. The results of photography are 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: viewing angle control angle range 18, 28, 38: observer 19, 29, 39: orthogonal plane (perpendicular line) of the transparent screen
20, 30: Floor 40: Ceiling α: Angle formed by reflected light with respect to the orthogonal plane (perpendicular) of the transparent screen β: Angle formed with respect to the orthogonal plane (perpendicular) of the transparent viewing angle control film (viewing angle limiting angle)
γ: 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)

A video projection system comprising a transparent screen, a video 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 video projection unit,
The image projection unit is arranged such that the reflection angle of the image light on the surface of the transparent screen on the side of the transparent viewing angle control film is within the range of the viewing angle control angle of the transparent viewing angle control film,
image light projected from the image projection unit forms an image on the transparent screen;
An image projection system, wherein reflected light from a surface of the transparent screen facing the transparent viewing angle control film is scattered by the transparent viewing angle control film. 2. The video projection system according to claim 1, wherein the upper limit of the range of the projection angle of the video light of said video projection unit is within the range of the viewing angle control angle of said transparent viewing angle control film. 3. The video projection system according to claim 1, wherein the viewing angle control angle of said 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 transmittance of 0% or more and less than 40% within the viewing angle control angle range, and a parallel light transmittance of 60% or more and 92% outside the viewing angle control angle range. 4. The image projection system according to any one of claims 1 to 3, wherein: 5. The video projection system according to claim 1, wherein said transparent screen and said transparent viewing angle control film constitute a laminate. 6. The video projection system of 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 transparent screen has a haze value of 35% or less. An image projection system according to any preceding claim, wherein the transparent screen comprises light reflective material. The image projection system according to any one of claims 1 to 8, wherein said transparent screen is at least part of a vehicle component. An image projection system according to any preceding claim, wherein the transparent screen is at least part of a building component.

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