JP3993980B2 - Transparent transmission screen - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rear projection transmission screen in which an image projected from a projector can be viewed from the opposite side of the projector across the screen, and in particular, by using a light scattering layer having special scattering characteristics, The present invention relates to a transmissive screen that is excellent in transparency and can visually recognize a background.
[0002]
[Prior art]
Conventionally, most of transmissive screens that have been put to practical use have used a polarizing film, a Fresnel lens sheet, a lenticular lens sheet, etc. in order to achieve high brightness and high contrast. However, such a conventional transmission screen is expensive because it uses a polarizing film or a lens sheet, and it is almost impossible to see the opposite side of the screen.
[0003]
By the way, advertising expressions that encourage purchase intent by putting posters or applying spray paint on the shop's show window are adopted. However, such an advertisement expression is static, and the content of the advertisement does not change unless reapplied or repainted. Therefore, it is conceivable to project a dynamic advertisement on a show window or the like using a projector or the like. However, since the show window or the like is highly transparent, the projected image passes through without being imaged.
On the other hand, if a conventional transmissive screen is attached to the show window, the projected image can be seen from the back, but the transmissive screen is not transparent, so the product can be seen from the outside. Will not be possible and will no longer make sense for the show window.
[0004]
[Problems to be solved by the invention]
Therefore, the object of the present invention is to be able to see through the opposite side of the screen opposite to the viewer by sticking to a transparent body such as a show window or a transparent window glass, or by combining with such a transparent body. Another object of the present invention is to provide a transmissive screen capable of clearly displaying an image from a projector.
[0005]
[Means for Solving the Problems]
As a result of diligent research on the conditions under which images can be projected on a fluoroscopic material, the present inventors have applied a forward scattering material to the screen, so that the video can be seen despite the fact that the opposite side of the screen can be seen through. Has been found to be able to project clearly, has led to the solution of this problem. Forward scattering means the property that incident light is scattered almost in front of the traveling direction and is not scattered backward. Such forward scattering is based on Mie scattering, that is, from the wavelength of light. Is also caused by scattering by spherical dielectric particles having a sufficiently large particle diameter.
[0006]
That is, the see-through transmissive screen of the present invention has a forward scattering light scattering layer.
[0007]
In addition, the see-through transmissive screen of the present invention is characterized in that the light scattering layer is made of a transparent binder containing spherical fine particles.
[0008]
In addition, the see-through transmissive screen of the present invention is characterized by having a transparent body on at least one surface of the light scattering layer.
[0009]
In addition, the see-through transmissive screen of the present invention has an antireflection layer on at least one surface of the see-through transmissive screen.
[0010]
Further, in the transparent transmission screen of the present invention, the spherical fine particles have an average particle diameter of 1.0 μm to 10.0 μm, and the relative refractive index n of the spherical fine particles with respect to the refractive index of the transparent binder is 0.91 <n <1.09 ( However, n ≠ 1).
[0011]
Further, the see-through transmissive screen of the present invention is characterized in that the haze is 3.0% or more and the image definition is 60.0% or more.
In the present invention, the haze is a haze value in JIS-K7105, and H = [Td / Tt] × lOO (%) [H: haze, Td: diffuse light transmittance, Tt: total light It is a value obtained from the equation of transmittance.
The image definition in the present invention is the value of image definition in JIS-K7105, and the maximum wave height [M] and the minimum wave height [m] at an optical comb of 0.125 mm are read using the transmission method. The value obtained by the following equation.
Image clarity [C _{( 0.125 )} ] = {M−m} / {M tens m} × lOO (%)
The value of the image definition in the present invention is expressed as an average value of the measurement results in the vertical and horizontal directions of the test piece.
[0012]
The transparent transmission screen of the present invention is characterized in that the transparent binder is glass or a polymer resin.
[0013]
The transparent transmission screen of the present invention is characterized in that the transparent body is glass or a polymer resin.
[0014]
In addition, the see-through transmissive screen of the present invention is characterized in that the transparent body is arranged on the projector side with respect to the light scattering layer.
Further, the transparent transmission screen of the present invention is such that the transparent body is arranged on the projector side with respect to the light scattering layer, and the refractive index of the transparent body is higher than the refractive index of the transparent binder of the light scattering layer. It is characterized by being low.
[0015]
In addition, the see-through transmissive screen of the present invention is characterized in that the transparent body is arranged closer to the viewer than the light scattering layer.
Further, in the transparent screen of the present invention, the transparent body is arranged on the viewer side with respect to the light scattering layer, and the refractive index of the transparent body is higher than the refractive index of the transparent binder of the light scattering layer. It is also characterized by being high.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The see-through transmissive screen of the present invention will be described in more detail.
[0017]
1 to 5 show an embodiment of the transmission screen of the present invention.
As shown in the figure, the transmission screen 1 of the present invention (hereinafter abbreviated as “screen” as appropriate) has a forward scattering light scattering layer 2 and is a single layer of the light scattering layer 2 ( In addition to (FIG. 4), the light scattering layer 2 and other layers (FIGS. 1 to 3 and 5) are included. Hereinafter, the light scattering layer 2 and other components will be described in detail.
[0018]
Specifically, the forward scattering light scattering layer 2 is formed by dispersing spherical fine particles satisfying the Mie scattering condition in a transparent binder.
Here, the transparent binder containing the spherical fine particles is not limited to a solid and may be a fluid such as a liquid or a liquid crystal as long as it is transparent and can uniformly hold the spherical fine particles. However, in order to maintain the shape of the screen with a single light scattering layer, glass or a polymer resin is preferable.
[0019]
The glass is not particularly limited as long as the transparency of the light-scattering layer is not lost, but in general, an oxide glass such as silicate glass, phosphate glass, and borate glass is practical. In particular, silicate glasses such as silicate glass, alkali silicate glass, soda lime glass, potash lime glass, lead glass, barium glass, and borosilicate glass are preferable.
When glass is used as the transparent binder, for example, it is preferable to form a plate glass by containing spherical fine particles in a raw material mainly composed of lime and silicic acid, and to flatten the surface by polishing the surface to form a platy plate glass. Thereby, transparency can be made high and it becomes suitable for the screen of this invention.
[0020]
The polymer resin is not particularly limited as long as the transparency of the light scattering layer is not lost. Polyester resin, acrylic resin, acrylic urethane resin, polyester acrylate resin, polyurethane acrylate resin, epoxy acrylate resin Resin, urethane resin, epoxy resin, polycarbonate resin, cellulose resin, acetal resin, vinyl resin, polyethylene resin, polystyrene resin, polypropylene resin, polyamide resin, polyimide resin, melamine resin, Thermoplastic resins such as phenolic resins, silicone resins, and fluorine resins, thermosetting resins, ionizing radiation curable resins, and the like can be used. These polymer resins are melted to contain spherical fine particles to form a sheet, thereby forming a light scattering layer, for example, a screen having a structure shown in FIG. Alternatively, a screen having a structure shown in FIG. 5, for example, can be obtained by forming a paint with spherical fine particles on another transparent body.
[0021]
As spherical fine particles to be contained in the transparent binder, inorganic fine particles such as silica, alumina, talc, zirconia, zinc oxide and titanium dioxide, and organic fine particles such as polymethyl methacrylate, polystyrene, polyurethane, benzoguanamine and silicone resin are used. Can be used. In particular, organic fine particles are preferable in that a spherical shape can be easily obtained.
[0022]
In order to impart good forward scattering properties to the light scattering layer, the average particle size of the spherical fine particles is preferably 1.0 μm to 10.0 μm, and more preferably 2.0 μm to 6.0 μm. By setting the average particle size to 1.0 μm or more and 10.0 μm or less, the proportion of the backscattered light in the scattered light can be sufficiently reduced. As a result, it is possible to project the image projected from the projector as a clear image while maintaining the transparency of the screen.
[0023]
In order to give the light scattering layer good forward scattering properties, the relative refractive index of the spherical fine particles relative to the refractive index of the transparent binder (the value obtained by dividing the refractive index of the spherical fine particles by the refractive index of the transparent binder, hereinafter simply referred to as “relative N is preferably 0.91 <n <1.09 (where n ≠ 1). By setting the relative refractive index n to a value larger than 0.91 or smaller than 1.09, the proportion of the backscattered light in the scattered light can be sufficiently reduced, while maintaining the transparency of the screen. In addition, the image projected from the projector can be projected as a clear image.
[0024]
The spherical fine particles satisfying the above conditions can be used alone or in combination of two or more. In the case of mixing two or more kinds, it may be two or more kinds of spherical fine particles having different refractive indexes, or may be simply two or more kinds of spherical fine particles having different particle diameters.
[0025]
As described above, by using a light scattering layer having a forward scattering property in which spherical fine particles having a certain range of average particle diameter are dispersed in a binder having a certain range of refractive index ratio, a surface used in a conventional screen is used. The image projected from the projector can be projected as a clear image while maintaining the transparency that cannot be obtained by the light scattering layer that scatters the image light due to unevenness or the like.
[0026]
The transmission screen of the present invention may be composed of a single layer of such a light scattering layer, but preferably has a structure having another transparent body on at least one surface of the light scattering layer.
When the light scattering layer is composed of a single layer, the particles may protrude from the screen surface to form surface irregularities, and the transparency may be reduced due to surface scattering. By adopting a structure having a transparent body, formation of such surface irregularities can be suppressed, and deterioration of transparency can be prevented.
[0027]
As a transparent body, the same glass as the transparent binder of a light-scattering layer can be used as a glass plate, or a polymer resin can be used as a sheet.
[0028]
Such a transparent body becomes a base material for forming a light scattering layer by coating a polymer resin together with spherical fine particles. Alternatively, another transparent body can be laminated on the light scattering layer formed on the transparent body directly or via a transparent adhesive layer or adhesive layer. 1-3 illustrate the laminated body which has a transparent body on both sides of a light-scattering layer.
[0029]
For example, the light scattering layer 2 is sandwiched between glass sheets by using a transparent intermediate film (adhesive layer) 4 or the like to form a laminated glass, and the structure shown in FIG. The screen 1 can be configured as a laminate having the structure shown in FIG. In the screen 1 shown in FIG. 1, a hard coat layer 6 is provided on a transparent body 3 made of a polymer resin.
As an adhesive layer or an adhesive layer, an acrylic resin, an epoxy resin, an ethylene / vinyl acetate resin, a polyvinyl ether resin, a polyvinyl acetal resin, a cellulose resin, a polyester resin, as long as the material does not hinder transparency. , Polyurethane resins, polyamide resins, polyolefin resins, phenol resins, cyanoacrylate resins and other synthetic resins, natural rubber, recycled rubber, chloroprene rubber, nitrile rubber, styrene / butadiene rubber Known adhesives and pressure-sensitive adhesives such as resin can be used.
[0030]
When the screen of the present invention is constituted by such a laminate, the transparent body 3 disposed on the projector side with respect to the light scattering layer 2 has a refractive index higher than that of the transparent binder of the light scattering layer 2. Low is preferred. On the other hand, the transparent body 3 disposed closer to the viewer than the light scattering layer 2 preferably has a higher refractive index than the refractive index of the transparent binder of the light scattering layer 2.
[0031]
In this way, by increasing the refractive index of the light scattering layer 2 and the transparent body 3 constituting the laminated body from the projector side toward the viewer side, the image light projected from the slant is directed to the screen in the perpendicular direction. be able to. This is shown in FIG. In general, in the case of a transmissive screen, when light is projected in parallel with the normal of the screen, a phenomenon called a hot spot (a phenomenon in which direct light from a projector is directly visible to a viewer) is unavoidable. In order to avoid this, the projection is performed with a certain angle with respect to the perpendicular 7 (two-dot chain line) of the screen 1 (thick solid line). In this case, the image light 8 (solid line arrow) can be directed in the perpendicular direction of the screen 1 by the refractive action of light by giving the refractive index of the material constituting the laminated body as described above. Here, it is particularly important to increase the refractive index of the transparent binder of the light scattering layer 2.
[0032]
Further, in such a configuration, the scattered image light 9 (broken arrows) scattered by the light scattering layer 2 is transmitted through the screen 1 at an angle spread from the normal direction of the screen 1 by the refraction of light. Will widen the viewing angle.
[0033]
Furthermore, the screen of the present invention may have an antireflection layer (not shown) on at least one surface. Thereby, the light quantity reduction of the image | video projected from the projector can be prevented and it can be made to visually recognize as a clear image by the viewer.
[0034]
The antireflection layer is a layer having a performance of canceling reflected light by utilizing the light interference action at the layer interface, and a known antireflection layer can be used. Specifically, it is a single layer with a low-refractive-index layer with high transparency such as silicon oxide or lithium fluoride so that the optical film thickness becomes 1/4 of the dominant wavelength for the purpose of antireflection. Alternatively, a layer in which a high refractive index layer such as titanium oxide or zinc oxide, a middle refractive index layer, or the like is appropriately stacked on such a low refractive index layer can be used.
[0035]
As described above, the screen of the present invention includes a light scattering layer having a forward scattering property, and is appropriately combined with other transparent bodies. As an optical characteristic of the entire screen, the haze is 3.0% or more, preferably 7.0% or more, more preferably 15.0% or more. The image definition is desirably 60.0% or more, preferably 65.0% or more, more preferably 70.0% or more.
Note that the haze and the image definition are within the above-described ranges by appropriately adjusting the content of the spherical fine particles contained in the light scattering layer and the thickness of the light scattering layer in a range where the forward scattering property of the light scattering layer is obtained. It is possible to adjust to.
By setting the haze to 3.0% or more and the image definition to 60.0% or more in this way, the image projected from the projector can be clearly displayed while providing sufficient transparency to the screen 1. Can be projected as
[0036]
【Example】
Examples of the present invention will be described below. “Part” and “%” are based on weight unless otherwise specified.
[0037]
[Example 1]
100 parts by weight of polyvinyl butyral resin (polymerization degree 1700, butyralization degree 66 mol%) is mixed with 40 parts by weight of triethylene glycol-2-ethylbutyrate as a plasticizer, and kneaded with a roll at 110 ° C. to obtain a thickness of 0 A transparent intermediate film 4 having a thickness of 5 mm was produced.
[0038]
On the other hand, a glass in which a light scattering layer 2 having a dry coating thickness of 35 μm is formed by applying a light scattering layer coating liquid a having the following composition on one side of a float glass plate 3 (refractive index 1.51) having a thickness of 3 mm and drying. Plate 3 was produced.
[0039]
<Light scattering layer coating solution a: relative refractive index n = 0.92>
・ 100 parts of polystyrene resin (Styron 666: Refractive index 1.59: Asahi Kasei Corporation)
・ Acrylic resin particles 2 parts (Techpolymer MBX-5: Refractive index 1.47
: Average particle size 5.0μm: Sekisui Plastics Co., Ltd.)
・ Methyl ethyl ketone 75 parts ・ Toluene 75 parts 【0040】
Subsequently, the transparent intermediate film 4 and the float glass plate 3 having a thickness of 3 mm (refractive index 1.51) are superposed in this order on the light scattering layer 2 side of the glass plate 3 on which the light scattering layer 2 is formed. Was put in a rubber bag, the pressure was reduced to 1.3 kPa, and the mixture was held at 120 ° C. for 30 minutes. Then, it is cooled and decompressed, taken out from the rubber bag, placed in an autoclave container, held for 20 minutes while heating and pressing at 140 ° C and 1.3 MPa, cooled, and seen through the structure of Fig. 2 A transparent screen 1 was prepared.
[0041]
When an image was projected on the screen 1 thus obtained from a downward direction of about 30 ° from the vertical line of the screen 1 using a liquid crystal projector (XV-P3: Sharp Corporation), the surface opposite to the projection surface was projected. A clear image could be seen. Further, since the screen 1 obtained in Example 1 has transparency, it was possible to sufficiently see the opposite side through the screen 1.
[0042]
The haze of the screen 1 obtained in Example 1 was 30.4%, and the image sharpness was 90.3%.
[0043]
[Example 2]
A hard coat layer coating solution having the following composition is applied to one surface of a polyethylene terephthalate film 3 (Lumirror T-60: refractive index 1.64: Toray Industries, Inc.) having a thickness of 100 μm, dried, and irradiated with ultraviolet light for 1-2 seconds with a high-pressure mercury lamp. Thus, a hard coat layer 6 having a dry coating thickness of 5 μm was formed. On the other side, a light scattering layer coating solution b and an adhesive layer coating solution having the following composition are sequentially applied and dried to dry the light scattering layer 2 having a dry coating thickness of 35 μm and the adhesive layer having a dry coating thickness of 10 μm. 5 was laminated. Next, the surface of the adhesive layer 5 was bonded to a float glass plate 3 (refractive index 1.51) having a thickness of 5 mm to produce a transmission screen 1 having the structure of FIG.
[0044]
<Hard coat layer coating solution>
・ 30 parts UV curable acrylate resin (Unidic 17-806: 80% solid content
: Dai Nippon Ink Chemical Co., Ltd.)
・ Photopolymerization initiator 1 part (Irgacure 651: Ciba Specialty
Chemicals)
・ Methyl ethyl ketone 35 parts ・ Toluene 35 parts 【0045】
<Light scattering layer coating solution b: relative refractive index n = 0.92>
・ 100 parts of polyester resin (Chemit 1249: Refractive index 1.56: Toray Industries, Inc.)
-Silicone resin particles 1.5 parts (Tospearl 120: Refractive index 1.44: Average particle size 2.0 μm
: GE Toshiba Silicone)
・ Methyl ethyl ketone 75 parts ・ Toluene 75 parts 【0046】
<Adhesive layer coating solution>
・ Acrylic adhesive 100 parts (Olivein BPSllO9: Refractive index 1.47: Solid content 40%
: Toyo Ink Manufacturer)
・ Isocyanate curing agent 2.4 parts (Olivein BHS8515: Solid content 38%
: Toyo Ink Manufacturer)
・ Ethyl acetate 100 parts 【0047】
Using a liquid crystal projector (XV-P3: SHARP) on the screen 1 obtained in this way, about 3 ° downward from the perpendicular to the glass 3 side with a low refractive index in the screen 1 configuration. The video was projected from. When the screen 1 was viewed from the side of the film 3 having a high refractive index opposite to the projection surface, a clear image could be viewed. In addition, since the screen 1 obtained in Example 2 has transparency, it was possible to sufficiently see the opposite side through the screen 1.
[0048]
The haze of the screen 1 obtained in Example 2 was 22.7%, and the image sharpness was 91.6%.
[0049]
[Example 3]
A light scattering layer coating solution c having the following composition is applied to one side of a polyethylene terephthalate film 3 (Lumirror T-60: Refractive index 1.64: Toray Industries, Inc.) having a thickness of 188 μm, and dried to give a sticky light scattering film having a thickness of 35 μm Layer 2 was formed and bonded to a triacetyl cellulose film 3 (Fujitac FT80: Refractive index 1.49: Fuji Photo Film Co., Ltd.) having a thickness of 80 μm to produce a transparent screen 1 having a structure shown in FIG.
[0050]
<Light scattering layer coating solution c: relative refractive index n = 1.06>
・ 100 parts urethane adhesive (Takelac A-971: Refractive index 1.50: Solid content 50%
: Takeda Pharmaceutical Company Limited)
・ Isocyanate curing agent 7.6 parts (Takenate A-3: solid content 75%: Takeda Pharmaceutical Company Limited)
・ Polystyrene resin particles 0.7 parts (Techpolymer SBX-6: Refractive index 1.59
: Average particle size 6.0μm: Sekisui Plastics Co., Ltd.)
[0051]
Using the liquid crystal projector (XV-P3: Sharp Corporation) on the screen 1 thus obtained, about 30 ° from the perpendicular to the triacetyl cellulose film 3 side of the low refractive index in the configuration of the screen 1 The image was projected from below. When the screen 1 was viewed from the surface of the polyethylene terephthalate film 3 having a high refractive index opposite to the projection surface, a clear image could be viewed.
In addition, since the screen 1 obtained in Example 3 has transparency, it was possible to sufficiently see the opposite side through the screen 1.
[0052]
The haze of the screen 1 obtained in Example 3 was 9.8%, and the image sharpness was 92.1%.
[0053]
[Example 4]
An antireflection coating agent (OA-201F: Nissan Chemical Industries, Ltd.) is applied to both sides of the screen 1 obtained in Example 3 so as to have a thickness of about 100 nm, dried, and subjected to an antireflection treatment. Screen 1 was produced.
[0054]
Using a liquid crystal projector (XV-P3: Sharp Corporation) on the screen 1 obtained in this way, on the triacetyl cellulose film 3 side of the screen 1 having a low refractive index, about 30 ° downward from the perpendicular. The video was projected from. When the screen 1 was viewed from the side of the polyethylene terephthalate film 3 having a high refractive index opposite to the projection surface, a clearer image could be viewed. Further, since the screen 1 obtained in Example 4 has transparency, it was possible to sufficiently see the opposite side through the screen 1.
[0055]
The haze of the screen 1 obtained in Example 4 was 9.7%, and the image sharpness was 92.2%.
[0056]
[Comparative example]
A liquid crystal projector (XV-P3: Sharp Corporation) is used to project an image from about 30 ° below the vertical line on a 5 mm thick float glass plate, and the float glass plate is visible from the opposite side of the projection surface. did. As a result, the opposite side could be seen through the float glass plate, but the video could not be seen.
[0057]
The haze of the float glass plate of this comparative example was 0.8%, and the image definition was 98.2%.
[0058]
【The invention's effect】
According to the see-through transmissive screen of the present invention, by adopting a forward-scattering light-scattering layer as the light-scattering layer, the image projected from the projector can be clearly displayed while maintaining the transparency of the screen. A transmissive screen that can be projected as an image can be provided.
[0059]
Therefore, the screen of the present invention can be a transmissive screen without using an expensive lens sheet such as a Fresnel lens or a lenticular lens, and has a transparency that cannot be obtained when such a lens sheet is used. Be able to get. In addition, the screen having the forward scattering light scattering layer can also be free from the limitation of the projection angle from the projector to the screen caused by the shape of the lens sheet.
[0060]
Further, according to the screen of the present invention, while increasing the absolute refractive index of the transparent binder of the light scattering layer, the refractive index of the light scattering layer and the transparent body of the laminate constituting the screen is changed from the projector side to the viewer side. By making it relatively higher toward the screen, it becomes possible to direct the projected image at an angle with respect to the normal direction of the screen toward the normal direction of the screen, and to increase the luminance in the normal direction of the screen. As well as being able to increase, the viewing angle can also be increased.
[0061]
Further, according to the screen of the present invention, by adjusting the light emission intensity of the image projected from the projector, for example, by sufficiently increasing the light emission intensity, the image projected on the screen can be made extremely clear, By moderately suppressing the emission intensity, the background over the screen and the projected image can be made visible at the same time.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a transmissive screen according to the present invention.
FIG. 2 is a sectional view showing another embodiment of the transmissive screen according to the present invention.
FIG. 3 is a sectional view showing another embodiment of the see-through transmissive screen of the present invention.
FIG. 4 is a sectional view showing another embodiment of the see-through transmissive screen of the present invention.
FIG. 5 is a sectional view showing another embodiment of the see-through transmissive screen of the present invention.
FIG. 6 is a conceptual diagram showing an optical path when an image is projected from a projector onto a see-through transmissive screen according to the present invention.
[Explanation of symbols]
1 ... Transparent screen that can be seen through
2 ... Light scattering layer
3 ... Transparent body
4 ... Transparent interlayer
5 ... Adhesive layer
6 ... Hard coat layer
7: Vertical line of screen 1
8 ... Direct optical path
9 ... Light path of scattered images
10 ... Viewer

Claims (4)

A transparent binder, and spherical fine particles having an average particle diameter of 1.0 to 10 μm and a relative refractive index n of 0.91 <n <1.09 (where n ≠ 1) with respect to the refractive index of the transparent binder. A see-through transmissive screen comprising a forward-scattering light-scattering layer and having an image definition of 60.0% or more.   The transmissive screen according to claim 1, further comprising an antireflection layer on at least one surface of the transmissive screen capable of being seen through.   2. The see-through transmissive screen according to claim 1, wherein the haze is 3.0% or more.   The transmissive screen according to claim 1, wherein the transparent binder is glass or a polymer resin.

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