JP6147932B2 - Transparent film, transparent screen including the same, and image projection apparatus including the same - Google Patents

Description

  The present invention relates to a transparent film suitably used for a projection type video display screen. The present invention also relates to a transparent screen provided with the transparent film and an image projection apparatus provided with the transparent screen.

  Conventionally, a combination of a Fresnel lens sheet and a lenticular lens sheet has been used as a projector screen. In recent years, there has been an increasing demand to project and display product information, advertisements, and the like while maintaining transparency on a show window of a department store or a transparent partition of an event space. In the future, it is said that the demand for highly transparent projection-type image display screens used for head-up displays, wearable displays, and the like will increase.

  However, since the conventional projector screen has low transparency, there is a technical problem that it cannot be applied to a transparent partition or the like. Therefore, various proposals have been made as follows. As a projector screen, a screen having a concave portion on the surface has been proposed (see Patent Document 1). A transmission screen having a transparent thin film layer containing diamond fine particles having a median diameter of 0.01 to 1 μm obtained by oxidizing a nanodiamond having a graphite phase obtained by an exposure method has been proposed (Patent Literature). 2). A highly transparent reflective screen film made of a polymer film comprising a matrix phase and a dispersed phase containing a thermoplastic resin has been proposed (see Patent Document 3). In order to prevent reflection on the surface of various screens such as transmissive screens and reflective screens, it is proposed that an anti-glare member having an anti-glare layer composed of black fine particles and a transparent binder be arranged on the surface of the screen. (See Patent Document 4). A light diffusion sheet in which a large number of condensing lenses are provided on one surface in the thickness direction has been proposed (see Patent Document 5). A reflective type comprising a low refractive index optical film made of a fluororesin having a refractive index of 1.4 or less, and a high refractive index optical film containing metal oxide fine particles coated and formed on the low refractive index optical film A coating type optical laminated film for a screen has been proposed (see Patent Document 6). In order to obtain a transmission screen with high transparency, a transparent light diffuser containing a thin film (0.2 to 400 μm) in which high refractive index nanoparticles are dispersed in a dispersion medium has been proposed (see Patent Document 7). ). There has been proposed a double-sided video film screen characterized by removing a hot spot including a transparent material and a photorefractive material made of silica contained or applied to the transparent material (see Patent Document 8).

JP 2006-146019 A JP 2011-1113068 A JP 2008-1112040 A Japanese Patent No. 4557191 JP 2007-240686 A Japanese Patent Laying-Open No. 2005-099675 JP 2014-153708 A JP-T-2006-503334

  However, the present inventors have found that Patent Documents 1 to 8 have the following technical problems. When the screen described in Patent Document 1 is applied to a show window, a transparent partition of an event space, and the like, there is a technical problem that the uneven portion is worn away with use, so that the performance cannot be maintained for a long time. The nanodiamond particles used in the transparent screen described in Patent Document 2 have a technical problem that there are many processing steps and production efficiency and production cost are inferior. The screen described in Patent Document 3 is obtained by stretching in at least one direction in order to develop anisotropy of the refractive index. However, the stretching for obtaining the anisotropy of the refractive index has a technical problem that the characteristics in the direction perpendicular to the stretching direction may become non-uniform, and further improvement is desired. Since the screen described in Patent Document 4 is provided with an antiglare member containing black fine particles such as carbon black having an average particle diameter of 1 to 6 μm, it is inferior in transparency, and the screen is grayish due to the influence of carbon black. There are specific issues. Since the light diffusion sheet described in Patent Document 5 is provided with a condensing lens, there is a technical problem that transparency is significantly impaired. The optical laminated film described in Patent Document 6 has a technical problem that light is reflected at the interface between the low refractive index layer and the high refractive index layer and is not suitable for a transmissive screen and is inferior in transparency. In the transparent light diffuser described in Patent Document 7, diamond or metal oxide having a large refractive index has low affinity with a thermoplastic resin, and particles are easily aggregated by kneading with an extruder. There is a technical problem that it is difficult to make a screen with few foreign objects. Further, there is a technical problem that a highly refracting particle has a light scattering intensity that is too high to make a screen with higher transparency. The film screen described in Patent Document 8 has a technical problem that it is cloudy in order to remove hot spots, has low light transmittance, and is inferior in transparency.

  The present invention has been made in view of the above technical problem, and its purpose is to clearly project and display product information, advertisements, etc. on a transparent partition or the like without impairing transmission visibility, and foreign matter is present. It is to provide less transparent film. Moreover, the objective of this invention is providing the image projection apparatus provided with the transparent screen provided with this transparent film, and this transparent film or this transparent screen, and a projection apparatus.

The present inventors have found that in order to solve the above technical problem, a result of intensive studies, the transparent film, and a resin having a refractive index n _1, and fine particles having a refractive index n ₂ smaller than the refractive index n ₁ The above-described technical problem is achieved by forming a light diffusing layer, adjusting the particle size and content of fine particles, and adjusting the difference between the refractive index n ₁ and the refractive index n ₂ within a specific range. It was found that can be solved. The present invention has been completed based on such findings.

That is, according to one aspect of the present invention,
A resin having a refractive index n _1, it comprises a light diffusing layer comprising a particulate having a smaller refractive index n ₂ than the refractive index n _1, primary particles of the fine particles, the median of 1nm~2.5μm Has a diameter,
The content of the fine particles is 0.01 to 14% by mass with respect to the resin,
The light diffusion layer has the following formula (1):
0.04 <refractive index n ₁ −refractive index n ₂ ≦ 0.5 (1)
A transparent film satisfying the above is provided.

  In the aspect of the present invention, the fine particles are preferably at least one selected from the group consisting of silica particles, barium sulfate particles, calcium carbonate particles, acrylic particles, and polystyrene particles.

  In the aspect of this invention, it is preferable that the said light-diffusion layer contains a thermoplastic resin.

  In an aspect of the present invention, the thermoplastic resin comprises at least one selected from the group consisting of acrylic resins, polyester resins, polyolefin resins, vinyl resins, polycarbonate resins, and polystyrene resins. Is preferred.

  In an aspect of the present invention, the thermoplastic resin is selected from the group consisting of polymethyl methacrylate resin, polyethylene terephthalate resin, polyethylene naphthalate resin, polypropylene resin, cycloolefin polymer resin, polyvinyl butyral resin, polycarbonate resin, and polystyrene resin. It preferably comprises at least one selected.

  In the embodiment of the present invention, the transparent film preferably has a haze value of 37% or less.

  In the embodiment of the present invention, the transparent film preferably has a total light transmittance of 70% or more.

  In the embodiment of the present invention, the transparent film preferably has a image clarity of 50% or more.

  According to the other aspect of this invention, the transparent screen provided with said transparent film is provided.

  According to the other aspect of this invention, the laminated body provided with said transparent film or said transparent screen is provided.

  According to another aspect of the present invention, there is provided a vehicle member provided with the above transparent film or the above transparent screen.

  According to the other aspect of this invention, the member for housing provided with said transparent film or said transparent screen is provided.

  According to another aspect of the present invention, there is provided an image projection apparatus comprising the above transparent film or the above transparent screen and a projection apparatus.

  When used as a transparent screen, the transparent film according to the present invention can clearly project and display product information, advertisements and the like on a transparent partition or the like without impairing transmission visibility, and has fewer foreign matters. That is, since the transparent film is excellent in transparency and image clarity, it can be suitably used as a transparent screen, and can also be suitably used in a vehicle member or a housing member. The transparent film can also be suitably used as a light guide plate used in an image display device, an image projection device, a scanner light source, and the like.

It is a cross-sectional schematic diagram of the thickness direction of one Embodiment of the transparent film by this invention. It is the schematic diagram which showed one Embodiment of the transparent screen and image projector by this invention. It is the figure which showed the scattered light luminance profile of the transparent film by this invention. It is the schematic of the measurement conditions of a scattered light luminance profile.

<Transparent film>
The transparent film according to the present invention comprises a light diffusion layer. The transparent film can be suitably used as a transparent screen, and can form a clear image on the transparent film without impairing transmission visibility. The transparent film may have a single-layer configuration composed of a light diffusing layer, or a laminate having a multilayer configuration further including other layers such as a protective layer, a base material layer, an adhesive layer, and an antireflection layer. It may be. The light diffusibility of the light diffusion layer can be evaluated by the scattered light luminance profile. That is, as the half-value width of the scattered light luminance profile is wider, light is diffused at a wider angle, and a bright and clear image can be formed on the transparent film. Furthermore, the transparent film by this invention can be used suitably also for the member for vehicles, and the member for houses. The transparent film according to the present invention can also be suitably used as a light guide plate and a light diffusing plate used in an image display device, an image projection device, a scanner light source, and the like.

  FIG. 1 shows a schematic cross-sectional view in the thickness direction of an embodiment of the transparent film according to the present invention. The transparent film 10 includes a light diffusion layer 11 in which fine particles 13 are dispersed in a resin 12.

  The transparent film according to the present invention may be used as it is as a transparent screen, or may be used as a transparent screen in a state of being attached to a support such as a transparent partition. Since a transparent screen is required not to impair transmission visibility, the transparent film preferably has high visible light transmittance and high transparency. In the present invention, the term “transparent” is sufficient as long as the transparency can be realized according to the application, and includes “translucent”.

  The transparent film preferably has a haze value of 37% or less, more preferably 1% or more and 35% or less, more preferably 1.3% or more and 30% or less, and even more preferably 1.5% or more. 25% or less. The transparent film has a total light transmittance of preferably 70% or more, more preferably 75% or more, still more preferably 77% or more, and even more preferably 80% or more. Preferably it is 85% or more. When the haze value and the total light transmittance of the transparent film are within the above ranges, the transparency is high and the transmission visibility can be further improved. In addition, in this invention, the haze value and total light transmittance of a transparent film are JIS-K-7361 and JIS-K- using a turbidimeter (Nippon Denshoku Industries Co., Ltd. product number: NDH-5000). It can be measured according to 7136.

  The image clarity of the transparent film is preferably 50% or more, more preferably 55% or more, still more preferably 60% or more, still more preferably 65% or more, and particularly preferably 70%. That's it. If the image clarity of the transparent film is within the above range, the image seen through the transparent screen becomes very clear. In the present invention, the image clarity is a value of image definition (%) when measured with an optical comb width of 0.125 mm in accordance with JIS K7374.

  The thickness of the transparent film is preferably 20 μm to 20 mm (20000 μm), more preferably 50 μm to 15 mm (15000 μm), and further preferably 50 μm, from the viewpoints of use, productivity, handleability, and transportability. It is -12 mm (12000 micrometers), More preferably, it is 80 micrometers-10 mm (10000 micrometers), Especially preferably, they are 100 micrometers-5 mm (5000 micrometers). In the present invention, the “transparent film” is a molded product of various forms such as a so-called film, sheet, plate (plate-shaped molded product), and laminated body (a laminate of a plurality of films, sheets, or plates). Is included.

(Light diffusion layer)
The light diffusion layer comprises a resin having a refractive index n _1, and fine particles having a refractive index n ₂ smaller than the refractive index n _1. Since the fine particles having a refractive index n ₂ smaller than the refractive index n ₁ of the resin have a high affinity with the resin, the fine particles are unlikely to form a large aggregate that becomes a foreign substance in the process of forming the light diffusion layer. As a result, a film with higher transparency can be obtained.

The number of foreign substances in the light diffusion layer is preferably 0 to 20, more preferably 0 to 10, and particularly preferably 0 to 5. Since the foreign matter deteriorates the sharpness of the image, if the number of the foreign matter is within the above numerical range, the projected image can be visually recognized as a clear image having no disturbance or bright spot. In the present invention, the number of foreign substances in the light diffusion layer is the number counted by the following measuring method.
(Measurement method of foreign matter)
The transparent film provided with the light diffusion layer was cut into a 20 cm square, and large aggregates (foreign matter) that could be visually confirmed were counted to determine the number of foreign matters.

The light diffusion layer has the following formula (1):
0.04 <refractive index n ₁ −refractive index n ₂ ≦ 0.5 (1)
And the following formula (2):
0.05 ≦ refractive index n ₁ −refractive index n ₂ ≦ 0.45 (2)
It is more preferable to satisfy the following formula (3):
0.1 ≦ refractive index n ₁ −refractive index n ₂ ≦ 0.4 (3)
It is further preferable to satisfy When the refractive index n _{1 of the} resin forming the light diffusion layer and the refractive index n _{2 of the} fine particles satisfy the above relational expression, the light scattering intensity in the light diffusion layer can be moderately suppressed.

  The thickness of the light diffusion layer is preferably 20 μm to 20 mm (20000 μm), more preferably 50 μm to 15 mm (15000 μm), still more preferably 50 μm to 12 mm (12000 μm), and even more preferably 80 μm to 10 mm. (10000 μm), particularly preferably 100 μm to 5 mm (5000 μm). If the thickness of the light diffusion layer is within the above range, the projection light emitted from the projection device is sufficiently diffused anisotropically while ensuring the transparency of the light diffusion layer. And the visibility of transmitted light can both be achieved. The light diffusion layer may have a single layer structure or a multilayer structure in which two or more layers are bonded together with an adhesive or the like.

(resin)
As the resin for forming the light diffusion layer, it is preferable to use a highly transparent resin in order to obtain a transparent film having high transparency. 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, and polycarbonate resins. Resin, Cellulose resin, Acetal resin, Vinyl resin, Polystyrene resin, Polyamide resin, Polyimide resin, Melamine resin, Phenol resin, Silicone resin, Polyarylate resin, Polyvinyl alcohol resin, Polychlorinated Thermoplastic resins such as vinyl resins, polysulfone resins, and fluorine resins, thermosetting resins, ionizing radiation curable resins, and the like can be used. Among these, the use of a thermoplastic resin is preferable from the viewpoint of the moldability of the transparent film, but is not particularly limited. As the thermoplastic resin, acrylic resins, polyester resins, polyolefin resins, vinyl resins, polycarbonate resins, and polystyrene resins are preferably used. Polymethyl methacrylate resin, polyethylene terephthalate resin, polyethylene naphthalate resin More preferably, polypropylene resin, cycloolefin polymer resin, cellulose acetate propionate resin, polyvinyl butyral resin, polycarbonate resin, and polystyrene resin are used. These resins can be used alone or in combination of two or more. Examples of the ionizing radiation curable resin include acrylic, urethane, acrylic urethane, epoxy, and silicone resins. Among these, those having an acrylate-based functional group, such as relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, many Monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone as oligomers or prepolymers such as (meth) arylate of polyfunctional compounds such as polyhydric alcohols and reactive diluents And polyfunctional monomers such as polymethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate Preferred are those containing a relatively large amount of rate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, etc. . Further, the ionizing radiation curable resin may be mixed with a thermoplastic resin and a solvent. Examples of thermosetting resins include phenolic resins, epoxy resins, silicone resins, melamine resins, urethane resins, urea resins, and the like. Among these, epoxy resins and silicone resins are preferable.

(Fine particles)
As the fine particles forming the light diffusion layer, an inorganic material or an organic material that can be atomized to a nano size can be suitably used, and it is preferable to use low refractive index particles satisfying the above formula (1). Inorganic fine particles having a low refractive index, is preferably a refractive index _{n 2} is 1.3 to 1.65, more preferably 1.35 to 1.6, more preferably at 1.37 to 1.55 And even more preferably 1.4 to 1.5. For example, particles obtained by atomizing silica (silicon oxide (n = 1.45)), barium sulfate (n = 1.64), calcium carbonate (n = 1.58), and the like can be given. Among these, silica is preferable, and hydrophobic silica is particularly preferable from the viewpoint of aggregation. Examples of the organic fine particles having a low refractive index include acrylic particles and polystyrene particles, and acrylic particles are preferable. These fine particles can be used singly or in combination of two or more. These fine particles may be commercially available.

The primary particles of the fine particles are 1 nm to 2.5 μm (2500 nm), preferably 5 nm to 2 μm (2000 nm), more preferably 10 nm to 1.5 μm (1500 nm), more preferably 20 nm to 1.0 μm (1000 nm), and even more. Preferably, it has a median diameter (D ₅₀ ) of ₅₀ nm to 0.5 μm (500 nm). When the median diameter of the primary particles of the fine particles is within the above range, when used as a transparent film, a sufficient diffusion effect of projected light can be obtained without impairing transmission visibility, so that a clear image can be displayed on a transparent screen. Can be projected. In the present invention, the median diameter (D ₅₀ ) of primary particles of fine particles is a particle size measured by a dynamic light scattering method using a particle size distribution measuring device (trade name: DLS-8000, manufactured by Otsuka Electronics Co., Ltd.). It can be obtained from the distribution.

  The content of fine particles in the light diffusion layer is preferably 0.01 to 14% by mass, more preferably 0.1 to 12% by mass, and further preferably 0.5 to 10% by mass with respect to the resin. %, And more preferably 1 to 6% by mass. If the content of the fine particles in the light diffusion layer is within the above range, the diffused light can be diffused by anisotropically and sufficiently diffusing the projection light emitted from the projection device while ensuring the transparency of the light diffusion layer. And the visibility of transmitted light can both be achieved.

(Base material layer)
A base material layer is a layer for supporting a transparent film, and can improve the intensity | strength of a transparent film. The base material layer is preferably made of a highly transparent resin or glass that does not impair the transmission visibility and desired optical properties of the transparent film. As such a resin, for example, a highly transparent resin similar to the above light diffusion layer can be used. Acrylic resins, acrylic urethane resins, polyester acrylate resins, polyurethane acrylate resins, epoxy acrylate resins, polyester resins, polyolefin resins, urethane resins, epoxy resins, polycarbonate resins, cellulose resins, Acetal resin, vinyl resin, polystyrene resin, polyamide resin, polyimide resin, melamine resin, phenol resin, silicone resin, polyarylate resin, polyvinyl alcohol resin, polyvinyl chloride resin, polysulfone resin Resins, thermoplastic resins such as fluorine resins, thermosetting resins, ionizing radiation curable resins, and the like can be suitably used. Moreover, you may use the transparent film which laminated | stacked 2 or more types of above-described resin. In addition, the thickness of a base material layer can be suitably changed according to material so that the intensity | strength may become suitable, for example, is good also as the range of 10-1000 micrometers.

(Protective layer)
The protective layer may be laminated on the surface side (viewer side) and / or the back side of the transparent film, and has functions such as light resistance, scratch resistance, substrate adhesion, and antifouling properties. It is a layer for giving. The protective layer is preferably formed using a resin that does not impair the transmission visibility and desired optical properties of the transparent film.
Examples of the material for the protective layer include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, cellulose resins such as diacetyl cellulose and triacetyl cellulose, acrylic resins such as polymethyl methacrylate, polystyrene, acrylonitrile / styrene copolymers, and the like. Examples thereof include styrene resins such as (AS resin), polycarbonate resins, and the like. In addition, polyolefin resins such as polyethylene, polypropylene, ethylene / propylene copolymers, olefin resins having cycloolefin or norbornene structures, vinyl chloride resins, amide resins such as nylon and aromatic polyamide, imide resins, Sulfone resin, polyether sulfone resin, polyether ether ketone resin, polyphenylene sulfide resin, vinyl alcohol resin, vinylidene chloride resin, vinyl butyral resin, arylate resin, polyoxymethylene resin, epoxy resin Or the blend of the said resin etc. are mentioned as an example of resin which forms a protective film. Other examples include ionizing radiation curable resins such as acrylics, urethanes, acrylic urethanes, epoxies, and silicones, mixtures of thermoplastic resins and solvents in ionizing radiation curable resins, and thermosetting resins. .

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

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

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

  The protective layer is formed by applying the coating liquid of the ionizing radiation (ultraviolet ray) radiation curable resin composition by a method such as spin coating, die coating, dip coating, bar coating, flow coating, roll coating, gravure coating, and the like. It can form by apply | coating to the surface side (viewer side), both surfaces of a back surface side, or any one surface, and hardening a coating liquid by the above means. In addition, a fine structure such as a concavo-convex structure, a prism structure, or a microlens structure can be provided on the surface of the protective layer according to the purpose.

(Adhesive layer)
An adhesion layer is a layer for sticking a transparent film on a support body. The pressure-sensitive adhesive layer is preferably formed using a pressure-sensitive adhesive composition that does not impair the transmission visibility and desired optical properties of the transparent film. Examples of the pressure-sensitive adhesive composition include natural rubber, synthetic rubber, acrylic resin, polyvinyl ether resin, urethane resin, and silicone resin. Specific examples of synthetic rubbers include styrene-butadiene rubber, acrylonitrile-butadiene rubber, polyisobutylene rubber, isobutylene-isoprene rubber, styrene-isoprene block copolymer, styrene-butadiene block copolymer, styrene-ethylene-butylene block. A copolymer is mentioned. Specific examples of the silicone resin system include dimethylpolysiloxane. These pressure-sensitive adhesives can be used singly or in combination of two or more. Among these, an acrylic adhesive is preferable.

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

  Moreover, as a monomer which has a carboxyl group which forms acrylic resin adhesive, the monomer containing carboxyl groups, such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, monobutyl maleate, and (beta) -carboxyethyl acrylate Can be mentioned.

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

  In the acrylic resin pressure-sensitive adhesive, in addition to the monomer having another functional group as described above, another monomer having an ethylenic double bond can be used. Examples of monomers having an ethylenic double bond include diesters of α, β-unsaturated dibasic acids such as dibutyl maleate, dioctyl maleate and dibutyl fumarate; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers A vinyl aromatic compound such as styrene, α-methylstyrene and vinyltoluene; (meth) acrylonitrile and the like. In addition to the monomer having an ethylenic double bond as described above, a compound having two or more ethylenic double bonds may be used in combination. Examples of such compounds include divinylbenzene, diallyl malate, diallyl phthalate, ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, methylene bis (meth) acrylamide, and the like.

  Furthermore, in addition to the above-described monomers, monomers having an alkoxyalkyl chain can be used. Examples of (meth) acrylic acid alkoxyalkyl esters include 2-methoxyethyl (meth) acrylate, methoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, and 3-methoxypropyl (meth) acrylate. , 2-methoxybutyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 4-ethoxybutyl (meth) acrylate And so on.

  As an adhesive composition, the homopolymer of the (meth) acrylic-acid alkylester monomer other than the above-mentioned acrylic resin adhesive may be sufficient. For example, (meth) acrylic acid ester homopolymers include poly (meth) acrylate methyl, poly (meth) ethyl acrylate, poly (meth) acrylate propyl, poly (meth) acrylate butyl, poly (meth) Examples include octyl acrylate. As a copolymer containing 2 or more types of acrylate units, methyl (meth) acrylate- (meth) ethyl acrylate copolymer, (meth) methyl acrylate- (meth) butyl acrylate copolymer, ( Examples include methyl (meth) acrylate- (meth) acrylic acid 2-hydroxyethyl copolymer, methyl (meth) acrylate- (meth) acrylic acid 2-hydroxy-3-phenyloxypropyl copolymer, and the like. As a copolymer of (meth) acrylic acid ester and other functional monomers, (meth) methyl acrylate-styrene copolymer, (meth) methyl acrylate-ethylene copolymer, (meth) acrylic A methyl acid- (meth) acrylic acid 2-hydroxyethyl-styrene copolymer is mentioned.

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

(Antireflection layer)
The antireflection layer is a layer for preventing reflection on the transparent film surface or the outermost surface of the laminate and reflection from external light. The antireflection layer may be laminated on the surface side (viewer side) of the transparent film or its laminate, or may be laminated on both surfaces. In particular, when used as a transparent screen, it is preferably laminated on the viewer side. The antireflection layer is preferably formed using a resin that does not impair the transmission visibility and desired optical properties of the transparent film or its laminate. As such a resin, for example, a resin curable by ultraviolet rays or an electron beam, that is, an ionizing radiation curable resin, a mixture of an ionizing radiation curable resin and a thermoplastic resin and a solvent, and a thermosetting resin are used. Among these, ionizing radiation curable resins are particularly preferable.

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

<Method for producing transparent film>
The manufacturing method of the transparent film by this invention includes the process of forming a light-diffusion layer. The step of forming the light diffusion layer can be molded by a known method such as an extrusion molding method, an injection molding method, a calender molding method, a coating method, a blow molding method, a compression molding method, a casting method comprising a kneading step and a film forming step. . Moreover, the injection molding method can also be used suitably from a viewpoint of the moldability of a thick film sheet. Hereinafter, each step of the extrusion molding method will be described in detail.

(Kneading process)
In the kneading step, a single screw kneading extruder or a twin screw kneading extruder may be used. When using a twin-screw kneading extruder, the average value over the entire screw length of the twin-screw kneading extruder is preferably 3 to 1800 KPa, more preferably 6 to 1400 KPa, while applying the above resin and fine particles. Is a step of kneading and obtaining a resin composition. If the shear stress is within the above range, the fine particles can be sufficiently dispersed in the resin. In particular, if the shear stress is 3 KPa or more, the dispersion uniformity of the fine particles can be further improved, and if it is 1800 KPa or less, decomposition of the resin is prevented and bubbles are prevented from being mixed in the light diffusion layer. Can do. The shear stress can be set in a desired range by adjusting the twin-screw kneading extruder. In the present invention, a resin composition obtained by adding a resin (master batch) to which fine particles have been added in advance and a resin to which fine particles have not been added is kneaded using a twin-screw kneading extruder to obtain a resin composition. Also good. The above is an example of the kneading process. A resin (masterbatch) to which fine particles have been added in advance may be produced using a single screw extruder, and a masterbatch is produced using a commonly known dispersant. May be.

  In addition to the above resin and fine particles, conventionally known additives may be added to the resin composition as long as the transparent visibility of the transparent film and the desired optical performance are not impaired. Examples of the additive include an antioxidant, a lubricant, an ultraviolet absorber, a compatibilizer, a nucleating agent, and a stabilizer. The resin and the fine particles are as described above.

  The twin-screw kneading extruder used in the kneading process is one in which two screws are inserted into a cylinder, and is configured by combining screw elements. As the screw, a flight screw including at least a conveying element and a kneading element can be suitably used. The kneading element preferably contains at least one selected from the group consisting of a kneading element, a mixing element, and a rotary element. By using a flight screw including such a kneading element, fine particles can be sufficiently dispersed in the resin while applying a desired shear stress.

(Film forming process)
The film forming step is a step of forming a film of the resin composition obtained in the kneading step. The film forming method is not particularly limited, and a film made of the resin composition can be formed by a conventionally known method. For example, the resin composition obtained in the kneading step 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. As the melt extruder, a single screw extruder, a twin screw extruder, a vent extruder, a tandem extruder, or the like can be used depending on the purpose.

  Subsequently, the melted resin composition is extruded into a sheet shape by a die such as a T die, and the extruded sheet material is rapidly cooled and solidified by a rotating cooling drum or the like, thereby forming a film. In addition, when performing the film forming process continuously with the above kneading process, the resin composition obtained in the kneading process is directly extruded into a sheet shape with a die in a molten state, and a film-shaped light diffusion layer is formed. It can also be molded.

  The film-shaped light diffusion layer obtained by the film forming step may be further uniaxially or biaxially stretched by a conventionally known method. The strength of the light diffusion layer can be improved by stretching the light diffusion layer.

<Transparent screen>
The transparent screen according to the present invention comprises the above transparent film. A transparent screen may consist only of said transparent film, and may further be equipped with support bodies, such as a transparent partition. The transparent screen may be a flat surface, a curved surface, or an uneven surface.

  The transparent screen may be a rear projection screen (transmission screen) or a front projection screen (reflection screen). That is, in the video display device including the transparent screen according to the present invention, the position of the light source may be on the viewer side with respect to the screen, or may be on the side opposite to the viewer.

(Support)
The support is for supporting the transparent film. The support may be any material that does not impair the transmission visibility and desired optical properties of the transparent screen. Examples thereof include a transparent partition, a glass window, a head-up display for passenger cars, and a wearable display.

<Vehicle members>
The vehicle member according to the present invention may be a laminate including the above-described transparent film or transparent screen and further including an antireflection layer or the like. Examples of the vehicle member include a windshield and a side glass. By providing the above-described transparent film or transparent screen, the vehicle member can display a clear image on the vehicle member without providing a separate screen.

<Housing materials>
The residential member according to the present invention may be a laminate including the above-described transparent film or transparent screen and further including an antireflection layer or the like. Examples of the house member include a window glass of a house, a convenience store, a glass wall of a road surface store, and the like. Since the housing member includes the transparent film or the transparent screen, a clear image can be displayed on the housing member without providing a separate screen.

<Image projection device>
An image projection apparatus according to the present invention includes the above-described transparent film or transparent screen and a projection apparatus. The projection device is not particularly limited as long as it can project an image on a screen. For example, a commercially available rear projector or front projector can be used.

  A schematic diagram of an embodiment of a transparent screen and an image projection apparatus according to the present invention is shown in FIG. The transparent screen 23 includes a transparent partition (support) 22 and a transparent film 21 on the viewer 24 side on the transparent partition 21. The transparent film 21 may include an adhesive layer in order to stick to the transparent partition 22. In the case of a rear projection type screen, the image projection device includes a transparent screen 23 and a projection device 25 </ b> A installed on the opposite side (rear side) of the viewer 24 with respect to the transparent partition 21. Projection light 26 </ b> A emitted from the projection device 25 </ b> A is incident from the back side of the transparent screen 23 and is anisotropically diffused by the transparent screen 23, so that the viewer 24 can visually recognize the diffused light 27 </ b> A. In the case of a front projection screen, the image projection apparatus includes a transparent screen 23 and a projection apparatus 25 </ b> B installed on the same side (front side) as the viewer 24 with respect to the transparent partition 21. The projection light 26B emitted from the projection device 25B enters from the front side of the transparent screen 23 and diffuses anisotropically by the transparent screen 23, so that the viewer 24 can visually recognize the diffused light 27B.

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

In Examples and Comparative Examples, various physical properties and measuring methods for performance evaluation are as follows.
(1) Haze The haze was measured according to JIS K7136 using a turbidimeter (Nippon Denshoku Industries Co., Ltd., product number: NDH-5000).
(2) Total light transmittance It measured based on JISK7361-1 using the turbidimeter (Nippon Denshoku Industries Co., Ltd. product number: NDH-5000).
(3) Foreign matter The film produced below was cut into a 20 cm square, and large aggregates (foreign matter) that could be visually confirmed were counted. The amount of foreign matter on the film was visually evaluated based on the following criteria.
[Evaluation criteria]
A: There were 0 to 5 foreign matters.
○: There were 6 to 20 foreign matters.
X: There were 21 or more foreign substances.
(4) Transparency The transparency of the film produced below was visually evaluated based on the following criteria.
[Evaluation criteria]
(Double-circle): It was very transparent without becoming cloudy.
○: Although it was not cloudy, the transparency was slightly inferior.
X: It was cloudy.
(5) Image clarity Image clarity (%) measured using an image clarity measuring instrument (Suga Test Instruments Co., Ltd., product number: ICM-1T) with an optical comb width of 0.125 mm in accordance with JIS K7374. The value of) was defined as image clarity. The larger the image sharpness value, the higher the transmission image clarity.
(6) Image clarity The film produced below as a transparent screen was moved from a position 50 cm away from the normal direction at an angle of 15 degrees with a mobile LED mini projector PP-D1S manufactured by Onkyo Digital Solutions Co., Ltd. Was used to project the image. Next, after adjusting the focus knob of the projector so that it is in focus on the surface of the screen, the images projected on the screen from two places 1 m ahead and 1 m behind the screen are visually checked as follows. Evaluation was based on the evaluation criteria.
[Evaluation criteria]
○: A clear image could be visually recognized.
Δ: The image was visible, but it was dark.
×: The image could not be visually recognized.
(7) Scattered light luminance profile Using a variable angle spectrophotometer (manufactured by Murakami Color Research Laboratory Co., Ltd., product number: GSP-2), the emitted light luminance at 0 degrees measured in the absence of a sample is defined as the incident light luminance. did. Next, the film produced below as a transparent screen was set as a sample, the measurement angle was changed from −80 degrees to +80 degrees, the emitted light luminance was measured, and the relative luminance with respect to the incident light luminance was calculated. Further, as a reference example, a transparent screen (made of glass) to which fine particles were not added was set, and similarly, the emitted light relative luminance was calculated. A schematic diagram of a method for measuring the scattered light luminance profile is shown in FIG.

[Example 1]
(1A) Production of thermoplastic resin pellets to which fine particles have been added (hereinafter referred to as “pellet production process”)
Polyethylene terephthalate (PET) pellets (manufactured by Bell Polyester Products, trade name: IFG8L) were prepared as the thermoplastic resin. The PET pellet (IFG8L) and 10% by mass of dry silica particles as fine particles with respect to the PET pellet (manufactured by Tokuyama Corporation, trade name: NHM-4N, hydrophobicity, refractive index 1.45, median diameter of primary particles) 90 nm) was charged into a twin-screw kneading extruder KZW-30MG manufactured by Technobel using a quantitative coil feeder. The pellets melt-kneaded at an extrusion temperature of 270 ° C. were pelletized to obtain PET pellets having an addition amount of silica particles of 10% by mass.
(2A) Production of light diffusion layer (film) (hereinafter referred to as “film production process”)
The (1A) silica particle-added PET pellets and PET pellets (IFG8L) were uniformly mixed at a mass ratio of 50:50 using a mixer (manufactured by Kawata Corporation, SMB series). The uniformly mixed pellets were put into a single-screw extruder hopper (manufactured by GM Co., Ltd.) to form a light diffusion layer (film) having a thickness of 100 μm. The screw diameter of the single screw extruder is 50 mm and the effective screw length (L / D) is 30, and a hanger coat type T-die is installed in the extruder via an adapter. The extrusion temperature was 270 ° C. The molten film discharged from the T-die is solidified by a cooling roll having a temperature of 70 ° C., and is then conveyed and wound by a pass roll at room temperature. The silica particle concentration of the obtained light diffusion layer (film) was 5% by mass. In addition, as a result of measuring the refractive index of the film which formed only the PET pellet (IFG8L) with the same method with the Abbe refractometer, it was 1.68. The refractive index difference (n ₁ −n ₂ ) between the resin and the fine particles was 0.23.
(3A) Evaluation of transparent screen When the produced light-diffusion layer (film) was used for the transparent screen as it was, the haze value was 18% and the total light transmittance was 89%, and it had sufficient transparency.
There were only two foreign substances measured by the above method, and the transparency was excellent. The image clarity was 82%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 2]
(2A) In the film production process, the film was prepared in the same manner as in Example 1 except that only the silica particle-added PET pellet of (1A) above was added to the uniaxial extruder hopper without mixing with the PET pellet (IFG8L). A light diffusion layer (film) having a thickness of 80 μm was prepared. The silica particle density | concentration of the obtained light-diffusion layer (film) was 10 mass%.
When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 30%, the total light transmittance was 89%, and it had sufficient transparency.
The number of foreign matters measured by the above method was as few as three, and the transparency was excellent. The image clarity was 75%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 3]
(1A) PET pellet (IFG8L) and 0.2% by mass of dry silica particles based on PET pellet (IFG8L) (trade name: NHM-4N, hydrophobicity, refraction) A ratio of 1.45 and a median diameter of primary particles of 90 nm) was placed in a plastic bag, and the plastic bag was shaken by hand for several tens of seconds to obtain a pellet having silica particles uniformly attached to the surface of the PET pellet.
(2A) Light diffusing layer (film) in the same manner as in Example 1 except that in the film production process, only the silica particle-adhered pellets were not mixed with the PET pellets (IFG8L) but were put into the single screw extruder hopper. Was made. The silica particle density | concentration of the obtained light-diffusion layer (film) was 0.2 mass%.
When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 3% and the total light transmittance was 89%, which was sufficiently transparent. Moreover, when the scattered light luminance profile of the produced light diffusion layer (film) was measured, a high relative luminance of the emitted light was observed even at a wide angle, and the light diffusion was compared with a transparent screen (reference example) to which no particles were added. It turned out that it is excellent in property.
There was only one foreign substance measured by the above method, and the transparency was excellent. The image clarity was 88%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 4]
(1A) In the pellet preparation process, except that dry silica particles (product name: NSS-4N, hydrophilicity, refractive index 1.45, median diameter of primary particles 90 nm made by Tokuyama Co., Ltd.) were used as fine particles. A light diffusion layer (film) was prepared in the same manner as in Example 1.
When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 18%, the total light transmittance was 89%, and it had sufficient transparency.
The number of foreign matters measured by the above method was as small as 12 and was excellent in transparency. The image clarity was 61%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 5]
(1A) In the pellet preparation process, except that dry silica particles (product name: QS-10, hydrophilicity, refractive index 1.45, median diameter of primary particles 15 nm, manufactured by Tokuyama Corporation) were used as the fine particles. A light diffusion layer (film) was prepared in the same manner as in Example 1.
When the produced light diffusing layer (film) was used for a transparent screen as it was, the haze value was 16%, the total light transmittance was 89%, and it had sufficient transparency.
The number of foreign matters measured by the above method was as small as 12 and was excellent in transparency. The image clarity was 62%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 6]
(1A) In the pellet preparation process, except that dry silica particles (product name: QS-30, hydrophilicity, refractive index 1.45, median diameter of primary particles 7 nm, manufactured by Tokuyama Corporation) were used as the fine particles. A light diffusion layer (film) was prepared in the same manner as in Example 1.
When the produced light diffusing layer (film) was used for a transparent screen as it was, the haze value was 16%, the total light transmittance was 89%, and it had sufficient transparency.
The number of foreign matters measured by the above method was as small as 14 and was excellent in transparency. The image clarity was 63%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 7]
(1A) In the pellet preparation step, except that dry silica particles (manufactured by Tokuyama Corporation, trade name: KS-20SC, hydrophobicity, refractive index 1.45, median diameter of primary particles 12 nm) were used as the fine particles. A light diffusion layer (film) was prepared in the same manner as in Example 1.
When the produced light diffusing layer (film) was used for a transparent screen as it was, the haze value was 15%, the total light transmittance was 89%, and it had sufficient transparency.
There were only two foreign substances measured by the above method, and the transparency was excellent. The image clarity was 77%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 8]
(1A) A light diffusion layer (film) was produced in the same manner as in Example 1 except that in the pellet production step, crosslinked acrylic particles (refractive index: 1.49, median diameter of primary particles: 90 nm) were used as fine particles.
When the produced light diffusing layer (film) was used for a transparent screen as it was, the haze value was 15%, the total light transmittance was 89%, and it had sufficient transparency.
There was only one foreign substance measured by the above method, and the transparency was excellent. The image clarity was 71%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 9]
(1A) A light diffusion layer (film) was prepared in the same manner as in Example 1 except that in the pellet preparation step, crosslinked acrylic particles (refractive index: 1.49, median diameter of primary particles: 370 nm) were used as fine particles.
When the produced light diffusing layer (film) was used for a transparent screen as it was, the haze value was 19% and the total light transmittance was 89%, which was sufficiently transparent.
The number of foreign matters measured by the above method was as small as 8 and was excellent in transparency. The image clarity was 63%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 10]
(1A) In the pellet preparation process, except that cross-linked acrylic particles (manufactured by Sekisui Plastics Co., Ltd., trade name: Techpolymer SSX-101, refractive index 1.49, median diameter of primary particles 1500 nm) are used as fine particles. In the same manner as in Example 1, a light diffusion layer (film) was produced.
When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 20%, the total light transmittance was 89%, and the film had sufficient transparency. Moreover, when the scattered light luminance profile of the produced light diffusion layer (film) was measured, a high relative luminance of the emitted light was observed even at a wide angle, and the light diffusion was compared with a transparent screen (reference example) to which no particles were added. It turned out that it is excellent in property.
The number of foreign matters measured by the above method was a little as 11 and was excellent in transparency. The image clarity was 61%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 11]
(1A) In the pellet production process, polyethylene naphthalate (PEN) pellets (manufactured by Teijin Ltd., trade name: Teonex TN-8065S) were used as the thermoplastic resin, and the extrusion temperature was changed to 290 ° C. A light diffusion layer (film) was produced in the same manner as in Example 1. In addition, as a result of measuring the refractive index of the film which formed only the PEN pellet (TN-8065S) by the same method with the Abbe refractometer, it was 1.77. The refractive index difference (n ₁ −n ₂ ) between the resin and the fine particles was 0.32.
When the produced light diffusing layer (film) was used for a transparent screen as it was, the haze value was 19% and the total light transmittance was 89%, which was sufficiently transparent.
There were only two foreign substances measured by the above method, and the transparency was excellent. The image clarity was 81%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 12]
(1A) Light diffusion layer (film) in the same manner as in Example 1 except that polycarbonate (PC) pellets (manufactured by Sumika Stylon Polycarbonate Co., Ltd., trade name: SD2201W) were used as the thermoplastic resin in the pellet preparation step. ) Was produced. In addition, as a result of measuring the refractive index of the film which formed only the PC pellet (SD2201W) by the same method with the Abbe refractometer, it was 1.59. The refractive index difference (n ₁ −n ₂ ) between the resin and the fine particles was 0.14.
When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 3% and the total light transmittance was 89%, which was sufficiently transparent.
There were only two foreign substances measured by the above method, and the transparency was excellent. The image clarity was 82%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 13]
(1B) Production of thermoplastic resin pellets to which fine particles have been added (hereinafter referred to as “pellet production process”)
Polyethylene terephthalate (PET) pellets (manufactured by Bell Polyester Products, trade name: IP252B, amorphous) were prepared as thermoplastic resins. The PET pellet (IP252B) and 0.02% by mass of dry silica particles as a fine particle with respect to the PET pellet (manufactured by Tokuyama Corporation, trade name: NHM-4N, hydrophobicity, refractive index 1.45, primary particles The median diameter was 90 nm) and charged into a twin-screw kneading extruder KZW-30MG manufactured by Technobel using a quantitative coil feeder. The pellets melt-kneaded at an extrusion temperature of 270 ° C. were pelletized to obtain PET pellets having an addition amount of silica particles of 0.02% by mass.
(2B) Production of light diffusion layer (sheet) (hereinafter referred to as “sheet production process”)
Using the above (1B) silica particle-added PET pellets, an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd., trade name: FNX-III) has an injection temperature of 270 ° C. and a thickness of 4 mm (4000 μm). A light diffusion layer (sheet) having a length of 20 cm was prepared.
(3B) Evaluation of transparent screen When the produced light-diffusion layer (sheet) was used for the transparent screen as it was, the haze value was 4% and the total light transmittance was 86%, and it had sufficient transparency.
There was only one foreign substance measured by the above method, and the transparency was excellent. The image clarity was 75%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 14]
(1B) In addition to changing the addition amount of dry silica particles to 0.012% by mass in the pellet production step, and (2B) changing the thickness of the light diffusion layer (sheet) to 20 mm (20000 μm) in the sheet production step. Produced a light diffusion layer (sheet) in the same manner as in Example 13.
When the produced light diffusion layer (sheet) was used for a transparent screen as it was, the haze value was 4% and the total light transmittance was 79%, which was slightly inferior to Example 13, but the transparent screen As it was applicable enough.
There was only one foreign substance measured by the above method, and the transparency was excellent. The image clarity was 71%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 15]
(1A) In the pellet manufacturing step, polycarbonate (PC) pellets (manufactured by Sumika Stylon Polycarbonate Co., Ltd., trade name: SD2201W) are used as the thermoplastic resin, and 13% by mass of crosslinked acrylic particles (based on PC pellets as fine particles) An acrylic particle-added PC pellet was obtained in the same manner as in Example 1 except that a refractive index of 1.49 and a median diameter of primary particles of 90 nm were used. Then, the light-diffusion layer (film) was produced by the method similar to Example 1 except having put only the obtained acrylic particle addition PC pellet in the uniaxial extruder hopper in the (2A) film production process. The silica particle density | concentration of the obtained light-diffusion layer (film) was 13 mass%.
When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 35%, the total light transmittance was 88%, and it had sufficient transparency.
The number of foreign matters measured by the above method was as few as three, and the transparency was excellent. The image clarity was 62%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image clarity, it was slightly inferior to Examples 1 to 11, but was sufficiently applicable as a transparent screen.

[Example 16]
In a reaction kettle equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction pipe, 300 parts by mass of deionized water and 0.6 parts by mass of polyvinyl alcohol (trade name: Kuraray Poval, manufactured by Kuraray Co., Ltd.) as a dispersant. Were added together and stirring was started. Next, 80 parts by mass of methyl methacrylate, 20 parts by mass of N-phenylmaleimide, 1 part by mass of Parroyl TCP manufactured by NOF Corporation as a polymerization initiator, and 0.22 parts by mass of 1-octanethiol as a chain transfer agent And the temperature was raised to 70 ° C. while passing nitrogen through the reaction kettle. The state reached 70 ° C. was maintained for 2 hours, further heated to 80 ° C. and maintained for 3 hours, then cooled, filtered, washed and dried to obtain a spherical acrylic copolymer (MMA / PhMI). The weight average molecular weight (Mw) of the acrylic copolymer (a-1) was 1.4 × 10 ⁵ . (1A) In the pellet preparation process, acrylic silica copolymer (MMA / PhMI) and 14% by mass of dry silica particles (acrylic copolymer (MMA / PhMI), manufactured by Tokuyama Corporation, trade name: NHM-) A silica particle-added acrylic pellet was obtained in the same manner as in Example 1 except that 4N, hydrophobicity, refractive index 1.45, and median diameter of primary particles 90 nm were used. Then, the light-diffusion layer (film) was produced by the method similar to Example 1 except having put only the obtained silica particle addition acrylic pellet in the uniaxial extruder hopper in the (2A) film production process. The silica particle density | concentration of the obtained light-diffusion layer (film) was 14 mass%.
When the produced light diffusing layer (film) was used for a transparent screen as it was, the haze value was 25% and the total light transmittance was 88%, and it had sufficient transparency.
The number of foreign matters measured by the above method was as few as three, and the transparency was excellent. The image clarity was 63%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image clarity, it was slightly inferior to Examples 1 to 11, but was sufficiently applicable as a transparent screen.

[Example 17]
An emulsification apparatus in which 30 sets of a wire mesh made of a 324/2400 mesh main wire mesh and a spacer having a length of 10 mm and an inner diameter of 10 mm are inserted into a cylindrical casing having an inner diameter of 15 mm (International Publication WO 2007/117041, Examples and Figures) 1-4), 1.5% by mass of benzoyl peroxide (polymerization initiator) and 20% by mass of ethylene glycol dimethacrylate (crosslinking agent) were dissolved in methyl methacrylate and 2,2,2- A mixed solution of trifluoroethyl methacrylate (methyl methacrylate: 2,2,2-trifluoroethyl methacrylate = 47: 53) was used using a 1% by mass PVA aqueous solution (manufactured by Kuraray Co., Ltd., product number: PVA 217). Milk at a flow rate of 17 ml / min and 33 ml / min with individual plunger pumps Introduced twice into the polymerization apparatus to obtain an acrylic emulsion. This acrylic emulsion was heated and stirred at 90 ° C. for 3 hours under a nitrogen atmosphere to obtain solid crosslinked acrylic fine particles. The obtained fine particles had a median diameter of 600 nm and a refractive index of 1.43.
(1A) A light diffusion layer (film) was prepared in the same manner as in Example 1 except that in the pellet preparation step, 5% by mass of the crosslinked acrylic fine particles obtained above were used as fine particles. When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 20%, the total light transmittance was 89%, and the film had sufficient transparency.
The number of foreign matters measured by the above method was as few as 8, and the transparency was excellent. The image clarity was 64%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 18]
An emulsification apparatus in which 35 sets of a unit consisting of a main net of 324/2400 mesh and a spacer having a length of 10 mm and an inner diameter of 10 mm are inserted into a cylindrical casing having an inner diameter of 15 mm (International Publication WO 2007/117041, Examples and Figures) 1-4), 1.5% by mass of benzoyl peroxide (polymerization initiator) and 20% by mass of ethylene glycol dimethacrylate (crosslinking agent) were dissolved, and methyl methacrylate was dissolved in 1% by mass of PVA. Using an aqueous solution (manufactured by Kuraray Co., Ltd., product number: PVA 217), each was introduced twice into the emulsifying apparatus by individual plunger pumps at a flow rate of 17 ml / min and 33 ml / min to obtain an acrylic emulsion. This acrylic emulsion was heated and stirred at 90 ° C. for 3 hours under a nitrogen atmosphere to obtain solid crosslinked acrylic fine particles. The obtained fine particles had a median diameter of 500 nm and a refractive index of 1.49.
(1A) A light diffusion layer (film) was prepared in the same manner as in Example 1 except that in the pellet preparation step, 5% by mass of the crosslinked acrylic fine particles obtained above were used as fine particles. When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 18%, the total light transmittance was 89%, and it had sufficient transparency. Moreover, when the scattered light luminance profile of the produced light diffusion layer (film) was measured, a high relative luminance of the emitted light was observed even at a wide angle, and the light diffusion was compared with a transparent screen (reference example) to which no particles were added. It turned out that it is excellent in property.
The number of foreign matters measured by the above method was as few as 8, and the transparency was excellent. The image clarity was 61%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 19]
(1A) In the pellet preparation step, silica particles (manufactured by Tokuyama Corporation, trade name: surface treatment SANSIL, brand SSP-04M, hydrophobicity, refractive index 1.45, median diameter of primary particles 400 nm) are used as fine particles. A light diffusion layer (film) was produced in the same manner as in Example 1 except that the amount of particles added was 1.5% by mass.
When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 6%, the total light transmittance was 90%, and it had sufficient transparency.
There were only two foreign substances measured by the above method, and the transparency was excellent. The image clarity was 92%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Example 20]
(1A) In the pellet preparation step, silica particles (manufactured by Tokuyama Corporation, trade name: surface treatment SANSIL, brand SSP-07M, hydrophobicity, refractive index 1.45, median diameter of primary particles 700 nm) are used as fine particles. A light diffusion layer (film) was produced in the same manner as in Example 1 except that the amount of particles added was 1.5% by mass.
When the produced light diffusing layer (film) was used for a transparent screen as it was, the haze value was 7%, the total light transmittance was 90%, and it had sufficient transparency.
There were only two foreign substances measured by the above method, and the transparency was excellent. The image clarity was 90%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of the image sharpness, it was possible to visually recognize the video clearly.

[Comparative Example 1]
(1A) Light diffusion in the same manner as in Example 1 except that polymethyl methacrylate (PMMA) pellets (trade name: Acrypet VH001, manufactured by Mitsubishi Rayon Co., Ltd.) were used as the thermoplastic resin in the pellet manufacturing process. A layer (film) was prepared. In addition, as a result of measuring the refractive index of the film which formed only the PMMA pellet (Acrypet VH001) by the same method with the Abbe refractometer, it was 1.49. The refractive index difference (n ₁ −n ₂ ) between the resin and the fine particles was 0.04.
When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 5%, the total light transmittance was 90%, and it had sufficient transparency.
The number of foreign matters measured by the above method was as few as three, and the transparency was excellent. The image clarity was 83%, and the image seen through the transparent screen was clear. Moreover, as a result of visual evaluation of image clarity, it was greatly inferior compared with Examples 1-11.

[Comparative Example 2]
(1A) In the pellet preparation process, except that cross-linked acrylic particles (manufactured by Sekisui Plastics Co., Ltd., trade name: Techpolymer SSX-103, refractive index 1.49, median diameter of primary particles 3000 nm) were used as the fine particles. In the same manner as in Example 1, a light diffusion layer (film) was produced.
When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 38% and the total light transmittance was 89%. Further, the image clarity was 38%, and the image seen through the transparent screen was unclear.
The number of foreign matters measured by the above method was as many as 35, and the quality was poor and the transparency was remarkably inferior. Moreover, as a result of visual evaluation of image clarity, it was greatly inferior compared with Examples 1-11.

[Comparative Example 3]
(1A) Example 1 except that titanium oxide particles (manufactured by Teika Co., Ltd., trade name: MT-01, refractive index: 2.72, median diameter of primary particles: 10 nm) were used as fine particles in the pellet preparation step. Similarly, a light diffusion layer (film) was produced.
When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 39% and the total light transmittance was 89%. The image clarity was 69%.
The number of foreign matters measured by the above method was as many as 188, which was inferior in quality and remarkably inferior in transparency. Since the refractive index of the titanium oxide particles is high, the fine particles tend to aggregate together when melt-kneaded with the thermoplastic resin, resulting in foreign matters.

[Comparative Example 4]
(1A) Example 3 and Example 3 except that titanium oxide particles (manufactured by Teika Co., Ltd., trade name: MT-01, refractive index 2.72, median diameter of primary particles 10 nm) were used as the fine particles in the pellet preparation step. Similarly, a light diffusion layer (film) was produced.
When the produced light diffusion layer (film) was used as it was for a transparent screen, the haze value was 8% and the total light transmittance was 89%.
The film was transparent without being clouded, and the projector image was clearly visible. The image clarity was 80%. However, the number of foreign substances measured by the above method was 68, which was inferior in quality. Since the refractive index of the titanium oxide particles is high, even when the titanium oxide particles are in a low concentration, the fine particles tend to aggregate together when melt-kneaded with the thermoplastic resin, resulting in foreign matters.

[Comparative Example 5]
(1A) Light diffusion in the same manner as in Example 1 except that zirconium oxide particles (manufactured by Kanto Denka Kogyo Co., Ltd., refractive index 2.40, median diameter of primary particles 11 nm) were used as the fine particles in the pellet preparation step. A layer (film) was prepared.
When the produced light diffusion layer (film) was used for a transparent screen as it was, the haze value was 29% and the total light transmittance was 89%.
The film was transparent without being clouded, and the projector image was clearly visible. The image clarity was 58%. However, the number of foreign substances measured by the above method was 99, which was inferior in quality. Since the refractive index of the zirconium oxide particles is high, the fine particles tend to aggregate when melt-kneaded with the thermoplastic resin, resulting in foreign matters.

[Comparative Example 6]
(1A) In the pellet manufacturing process, the amount of dry silica particles (trade name: NHM-4N, hydrophobicity, refractive index 1.45, median diameter of primary particles 90 nm, manufactured by Tokuyama Corporation) was changed to 15% by mass. (2A) In the film production process, light was mixed in the same manner as in Example 1 except that only the obtained silica particle-added PET pellets were not mixed with the PET pellets (IFG8L) and were put into a single screw extruder hopper. A diffusion layer (film) was prepared. The silica particle concentration of the obtained light diffusion layer (film) was 15% by mass.
When the produced light diffusion layer (film) was directly used for a transparent screen, the haze value was 44% and the total light transmittance was 88%. The image clarity was 50%.
Although there were few foreign substances measured by the said method, the film was cloudy and was not applicable as a transparent screen.

Table 1 shows details of the light diffusion layers prepared in Examples and Comparative Examples.

Table 2 shows the results of various physical properties and performance evaluation of the transparent films prepared in Examples and Comparative Examples.

DESCRIPTION OF SYMBOLS 10 Transparent film 11 Light-diffusion layer 12 Resin 13 Fine particle 21 Transparent film 22 Transparent partition (support body)
23 Transparent screen 24 Viewer 25A, 25B Projection device 26A, 26B Projection light 27A, 27B Diffuse light

Claims (13)

A transparent screen comprising a transparent film,
The transparent film is made comprises a resin having a refractive index n _1, a light diffusing layer comprising a particulate having a refractive index n ₂ smaller than the refractive index n _1,
The primary particles of the fine particles have a median diameter of 1 nm to 400 nm ,
The content of the fine particles is 0.1 to 14% by mass with respect to the resin,
The light diffusion layer has the following formula (1):
0.19 ≦ refractive index n ₁ −refractive index n ₂ ≦ 0.5 (1)
The filling,
The light diffusion layer has a thickness of 50 μm to 20 mm,
The haze value is 37% or less,
A transparent screen having the following image clarity of 60% or more.
Here, the image clarity is a value of image clarity (%) when measured with an optical comb width of 0.125 mm in accordance with JIS K7374. The fine particles are at least one silica particles, selected calcium particles carbonated, and from acrylic particles child or Ranaru group, transparent screen according to claim 1.   The transparent screen according to claim 1, wherein the fine particles are hydrophobic silica particles.   The transparent screen as described in any one of Claims 1-3 in which the said light-diffusion layer comprises a thermoplastic resin. The thermoplastic resin is, Po Riesuteru resins, vinyl-based resin, comprising at least one member selected from the group consisting of polycarbonate resin, and a polystyrene resin, a transparent screen according to claim 4. The thermoplastic resin is, Po triethylene terephthalate resin, comprising a polyethylene naphthalate resin, Po polyvinyl butyral resin, polycarbonate resin, and at least one member selected from the group consisting of polystyrene resin, according to claim 4 or 5 Transparent screen.   The transparent screen as described in any one of Claims 1-6 whose total light transmittance is 70% or more.   The transparent screen according to claim 1, wherein the light diffusion layer has a single layer configuration.   The transparent screen according to any one of claims 1 to 7, further comprising at least one layer selected from the group consisting of a protective layer, a base material layer, an adhesive layer, and an antireflection layer.   The laminated body provided with the transparent screen as described in any one of Claims 1-9.   The vehicle member provided with the transparent screen as described in any one of Claims 1-9.   The member for housing provided with the transparent screen as described in any one of Claims 1-9.   An image projection apparatus comprising the transparent screen according to claim 1 and a projection apparatus.