WO2018131684A1 - Transparent screen, video projection laminated plate, video display system, and method for manufacturing transparent screen - Google Patents

Abstract

A transparent screen comprises a first transparent layer, a reflective layer that reflects light of projected video, and a second transparent layer provided on the side opposite to the first transparent layer with the reflective layer as a reference, and allows a background to be visually recognizable, wherein when a surface on the side opposite to the reflective layer of the first transparent layer is defined as a reference plane, the reflective layer has a plurality of reflective inclined planes that are inclined in the same direction with respect to the reference plane and reflect the light, and the plurality of reflective inclined planes each have recesses and protrusions and are formed in a striped pattern when viewed from the normal direction of the reference plane.

Description

Transparent screen, image projection laminated plate, image display system, and method of manufacturing transparent screen

The present invention relates to a transparent screen, a video projection laminated plate, a video display system, and a method for manufacturing a transparent screen.

The video projection structure described in Patent Document 1 includes a first transparent layer having random irregularities formed on the surface, and a reflective film formed on a surface of the first transparent layer on which random irregularities are formed. And a second transparent layer formed on the reflective film. This video projection structure functions as a transparent window when a video is not projected, and functions as a screen when a video is projected.

International Publication No. 2015/186668

FIG. 17 is a diagram showing a conventional transparent screen. The conventional transparent screen 120 displays the image projected from the projector 112 to the user 113. The transparent screen 120 includes a first transparent layer 132, a reflective layer 133 that reflects the light of the projected image, and a second transparent layer provided on the opposite side of the first transparent layer 132 with respect to the reflective layer 133. Layer 135. The first transparent layer 132 has irregularities on a flat surface in contact with the reflective layer 133. A reflective layer 133 is formed along the unevenness.

By the way, a phenomenon called a hot spot may occur. The hot spot is a phenomenon in which the center of the screen looks bright and bright when an image is projected from the projector onto the screen. The hot spot is caused by regular reflection of incident light on the image projection surface in contact with the atmosphere of the screen, and is observed in the regular reflection direction.

Conventionally, the direction in which a hot spot is observed is the same as the direction in which a bright image is observed.

An object of the present disclosure is to provide a transparent screen that can separate a direction in which a hot spot is observed from a direction in which a bright image is observed.

According to one aspect of the present disclosure,
A first transparent layer, a reflective layer that reflects light of a projected image, and a second transparent layer provided on the opposite side of the first transparent layer with respect to the reflective layer, Transparent screen,
The reflective layer has a plurality of reflective inclined surfaces that are inclined in the same direction with respect to the reference surface and reflect the light, when a surface of the first transparent layer opposite to the reflective layer is used as a reference surface. And
Each of the plurality of reflective inclined surfaces has irregularities, and a transparent screen is provided that is formed in a stripe shape when viewed from the normal direction of the reference surface.

According to the transparent screen of the present disclosure, the direction in which the hot spot is observed and the direction in which the brightness of the image is the brightest can be separated.

FIG. 1 is a diagram illustrating a video display system according to an embodiment. FIG. 2 is a diagram illustrating a transparent screen according to an embodiment. FIG. 3 is a diagram illustrating an example of a measuring apparatus that measures the relationship between the incident angle of incident light and the brightness of a transparent screen while maintaining the output angle of reflected light constant. FIG. 4 is a diagram illustrating an example of a measurement result of the measurement apparatus of FIG. FIG. 5 is a diagram illustrating an example of a measuring apparatus that measures the relationship between the emission angle of reflected light and the brightness of a transparent screen while maintaining the incident angle of incident light constant. FIG. 6 is a diagram illustrating an example of a measurement result of the measurement apparatus of FIG. FIG. 7 is a diagram illustrating the angle of view of the projector according to the embodiment. FIG. 8 is a diagram illustrating an example of a positional relationship between the transparent screen of the video projection matching plate, the projector, and the user as viewed from the front of the vehicle. FIG. 9 is a diagram illustrating another example of the positional relationship among the transparent screen of the video projection matching plate, the projector, and the user as viewed from the front of the vehicle. FIG. 10 is a diagram illustrating still another example of the positional relationship among the transparent screen of the video projection laminated plate, the projector, and the user as viewed from the front of the vehicle. FIG. 11 is a flowchart illustrating a method for manufacturing a transparent screen according to an embodiment. FIG. 12 is a diagram illustrating an example of steps for forming a plurality of inclined surfaces in a striped pattern in the first transparent layer. FIG. 13 is a diagram illustrating an example of steps for forming irregularities on the slope of the first transparent layer. FIG. 14 is a diagram illustrating an example of steps for forming the reflective layer. FIG. 15 is a diagram illustrating an example of a step of forming the second transparent layer. It is a figure which shows the video display system by a modification. It is a figure which shows the conventional transparent screen. FIG. 18A is a semilogarithmic graph showing the luminance characteristics of the image projection laminated board according to Example 1. FIG. FIG. 18B is a linear graph illustrating the luminance characteristics of the image projection laminated plate according to the first example. FIG. 19A is a semilogarithmic graph showing the luminance characteristics of the image projection laminated board according to Example 2. FIG. 19B is a linear graph showing luminance characteristics of the image projection laminated plate according to the second example. FIG. 20A is a semilogarithmic graph showing the luminance characteristics of the image projection laminated board according to Example 3. FIG. 20B is a linear graph illustrating the luminance characteristics of the image projection laminated plate according to the third example. FIG. 21A is a semilogarithmic graph showing the luminance characteristics of the image projection laminated board according to Comparative Example 1. FIG. 21B is a linear graph showing luminance characteristics of the image projection laminated plate according to Comparative Example 1. FIG. 22A is a semilogarithmic graph showing the luminance characteristics of the image projection laminated plate according to Comparative Example 2. FIG. 22B is a linear graph showing the luminance characteristics of the image projection laminated board according to Comparative Example 2.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof is omitted. In the present specification, the user side is referred to as the front with respect to the transparent screen, and the side opposite to the user is referred to as the rear with respect to the transparent screen.

(Video display system)
FIG. 1 is a diagram illustrating a video display system according to an embodiment. In FIG. 1, the structure of the transparent screen 20 is shown enlarged.

The video display system 10 includes a video projection matching plate 11 that can visually recognize the background, and a projector 12 that projects a video on the video projection matching plate 11. A general projector is used as the projector 12.

(Image projection laminated board)
The video projection matching plate 11 displays a video projected from the front to the front user 13 and makes the front user 13 visually recognize the back background. The background behind the screen may be visible when the image is not projected, and may be visible or not visible when the image is projected.

The video projection matching plate 11 has a video projection surface 11a in contact with the atmosphere. A hot spot is generated by the regular reflection of the incident light IL on the image projection surface 11a and the surface in contact with the air on the opposite side. The hot spot is observed at a position in the regular reflection direction (for example, the position of the user 14 indicated by a broken line) and is not observed at other positions (for example, the position of the user 13 indicated by a solid line).

The image projection matching plate 11 may be a flat plate or a curved plate. The curved plate may be either one having a convex shape toward the user 13 or one having a concave shape toward the user 13.

The use of the image projection laminated board 11 is not particularly limited, but for example, a window plate of a vehicle such as an automobile or a train, a window plate of a building, a window plate of a show window, a window plate of a refrigerated showcase, an interior of a vehicle or a building For example, a partition that separates the rooms.

The image projection alignment plate 11 includes a transparent screen 20, a first transparent plate 21 provided on one side (for example, the rear side) of the transparent screen 20, and a second transparent plate provided on the opposite side (for example, the front side) of the transparent screen 20. Plate 22.

The transparent screen 20 displays the image projected from the front to the front user 13 and makes the front user 13 visually recognize the back background. The structure of the transparent screen 20 will be described later.

(Transparent plate)
As the first transparent plate 21 and the second transparent plate 22, for example, glass plates are used. In this case, a laminated glass is obtained as the image projection laminated plate 11. The method for producing a laminated glass includes, for example, the following steps (1) to (3). (1) A polymer in which the first glass plate 21, the first adhesive layer 23, the transparent screen 20, the second adhesive layer 24, and the second glass plate 22 are stacked in this order is placed inside the vacuum bag. Put in. The order of stacking may be reversed. (2) While degassing the inside of the vacuum bag containing the polymer, the vacuum bag is pressurized and heated in an atmospheric furnace or the like. (3) The polymer taken out from the vacuum bag is pressurized and heated in an autoclave.

Examples of glass of the glass plate include soda lime glass, aluminosilicate glass, alkali-free glass, and borosilicate glass. The glass may be either untempered glass or tempered glass. Untempered glass is obtained by forming molten glass into a plate shape and slowly cooling it. Examples of the molding method include a float method and a fusion method. The tempered glass may be either physically tempered glass or chemically tempered glass. Physically tempered glass strengthens the glass surface by rapidly cooling a uniformly heated glass plate from a temperature near the softening point and generating a compressive stress on the glass surface due to the temperature difference between the glass surface and the inside of the glass. . Chemically tempered glass is obtained by strengthening the glass surface by generating a compressive stress on the glass surface by an ion exchange method or the like.

The glass plate may be either a flat plate or a curved plate. Gravity molding, press molding, or the like is used as bending molding for bending a flat plate into a curved plate. In bending, the glass surface may be strengthened by rapidly cooling a uniformly heated glass plate from a temperature near the softening point and generating a compressive stress on the glass surface due to a temperature difference between the glass surface and the inside of the glass. Physically tempered glass is obtained. The chemically strengthened glass can be obtained by generating a compressive stress on the glass surface by an ion exchange method or the like after bending.

The plate thickness of the glass plate is not particularly limited, but is, for example, 0.1 mm or more and 20 mm or less.

A resin plate may be used as the first transparent plate 21 and the second transparent plate 22. One of the first transparent plate 21 and the second transparent plate 22 may be a glass plate and the other may be a resin plate. Further, the number of transparent plates included in the image projection laminated plate may be three or more.

(Adhesive layer)
The first adhesive layer 23 adheres the first transparent plate 21 and the transparent screen 20. The second adhesive layer 24 bonds the second transparent plate 22 and the transparent screen 20. Although the thickness of the 1st contact bonding layer 23 and the 2nd contact bonding layer 24 is respectively not limited, For example, they are 0.01 mm or more and 1.5 mm or less, Preferably they are 0.3 mm or more and 0.8 mm or less.

The first adhesive layer 23 and the second adhesive layer 24 may be formed of different materials, but are preferably formed of the same material. The first adhesive layer 23 and the second adhesive layer 24 are formed of, for example, a thermoplastic resin, a thermosetting resin, an ultraviolet curable resin, or the like, and preferably a vinyl polymer, an ethylene-vinyl monomer copolymer It is formed of at least one selected from a coalescence, a styrene copolymer, a cycloolefin copolymer, a polyurethane resin, a urethane acrylate resin, a fluororesin, and an acrylic resin.

As the thermoplastic resin, polyvinyl butyral resin (PVB) and ethylene-vinyl acetate copolymer resin (EVA) are typical. A typical example of the thermosetting resin is urethane acrylate resin. In the case of a thermoplastic resin or a thermosetting resin, adhesion is performed by heat treatment. On the other hand, in the case of an ultraviolet curable resin, adhesion is performed by ultraviolet irradiation. The urethane acrylate resin can be cured by ultraviolet rays.

(Transparent screen)
The transparent screen 20 displays the image projected from the front to the front user 13 and makes the front user 13 visually recognize the back background. When the haze value of the transparent screen 20 is 10% or less, sufficient transparency can be obtained and the background can be visually recognized well. In addition, the haze value of the glass plate used as the 1st transparent plate 21 or the 2nd transparent plate 22 is 1% or less normally.

The haze value is measured in accordance with Japanese Industrial Standard (JIS K7136), and the transmitted light that is transmitted through the test plate to be measured in the thickness direction deviates by 2.5 ° or more from the incident light due to forward scattering. As a percentage. As a light source used for measuring the haze value, a D65 light source described in Japanese Industrial Standard (JIS Z8720: 2012) is used.

The transparent screen 20 may not have flexibility, but may have flexibility so that it can be deformed into various shapes.

FIG. 2 is a diagram showing a transparent screen according to an embodiment. In FIG. 2, the unevenness of the reflective slope 45 of the reflective layer 34 is exaggerated. The transparent screen 20 includes a base sheet 31, a first transparent layer 32, a reflective layer 34, a second transparent layer 35, a protective sheet 36, and the like in this order from the rear side to the front side.

The substrate sheet 31 may be either a transparent glass sheet or a transparent resin sheet, but is preferably a transparent resin sheet from the viewpoint of flexibility. The transparent resin sheet is formed of, for example, polycarbonate, PET, PEN, cycloolefin polymer, or polyester.

The first transparent layer 32 is formed on the surface of the base sheet 31 and has irregularities on the surface opposite to the base sheet 31. The first transparent layer 32 is made of, for example, a transparent resin. The resin may be any of a photocurable resin, a thermoplastic resin, and a thermosetting resin, and is formed by, for example, an imprint method.

The reflective layer 34 is formed in a zigzag shape along the irregularities on the surface of the first transparent layer 32. The reflection layer 34 has projections and depressions on the front surface thereof, and displays an image by diffusely reflecting the image light projected from the front. The reflective layer 34 allows the background to be visually recognized by transmitting a part of the light from the rear to the front. The irregularities are preferably irregular irregularities.

The reflective layer 34 may be formed of a material that reflects light, for example, a metal such as aluminum or silver, a metal oxide, or a metal nitride. The reflective layer 34 may have either a single layer structure or a multilayer structure, and may include at least one of a metal layer and a dielectric layer. As a method for forming the reflective layer 34, for example, a vacuum deposition method or a sputtering method is used.

The reflective layer 34 may include a dielectric multilayer film. The dielectric multilayer film can be formed by a method of laminating a plurality of dielectrics having different refractive indexes. Examples of the high refractive index dielectric include Si ₃ N ₄ , AlN, NbN, SnO ₂ , ZnO, SnZnO, Al ₂ O ₃ , MoO, NbO, TiO ₂ and ZrO ₂ . Examples of the dielectric having a lower refractive index than the dielectric having a higher refractive index include SiO ₂ , MgF ₂ , and AlF ₃ .

The second transparent layer 35 fills the unevenness of the reflective layer 34. The second transparent layer 35 may be formed of a transparent resin similarly to the first transparent layer 32, and is preferably formed of a resin having substantially the same refractive index as that of the first transparent layer 32.
Here, an adhesion layer (not shown) may be provided between the first transparent layer 32 and / or the second transparent layer 35 and the reflective layer 34. The adhesion layer is made of a material capable of imparting adhesion to the first transparent layer 32 and / or the second transparent layer 35, and a resin material is preferable. The resin is preferably a polymer having a linear main chain. From the viewpoint of adhesion, the adhesion layer preferably has low water absorption. Specifically, linear acrylic resin, polyester resin, polyurethane resin, polyurethane acrylate resin, polycarbonate resin, polyvinyl butyral resin, cycloolefin resin polymer, cycloolefin copolymer resin, ethylene / vinyl acetate copolymer resin, etc. Is mentioned.

The protective sheet 36 may be formed in the same manner as the base sheet 31 and is preferably formed of the same material as the base sheet 31. The base sheet 31 and the protective sheet 36 have arbitrary configurations, and the transparent screen 20 may not have at least one of the base sheet 31 and the protective sheet 36.

(Details of transparent screen)
The first transparent layer 32 is formed in a sawtooth shape in a sectional view. The first transparent layer 32 has a plurality of inclined surfaces 42 that are inclined in the same direction with respect to the reference surface 41 when the surface 41 of the first transparent layer 32 opposite to the reflective layer 34 is the reference surface 41. Each inclined surface 42 is inclined so as to be separated from the reference surface 41 from one end (for example, the lower end) toward the other end (for example, the upper end). The plurality of slopes 42 are formed in stripes when viewed from the normal direction of the reference surface 41. The stripe line may be a straight line or a curved line. The inclination angle of each inclined surface may have a distribution within about ± 30% with respect to the average value of the inclination angles of the plurality of inclined surfaces as long as the inclination direction is the same with respect to the reference surface 41. Here, the distribution refers to a graph of the plurality of slopes 42 in which the horizontal axis represents the inclination angle and the vertical axis represents the count number. Further, the width W of the slope 42 may have a distribution within about ± 30% with respect to the average value of the width W of each slope 42. Here, the distribution refers to a graph of the width W of the slope 42 in which the horizontal axis is the width and the vertical axis is the count number.

The inclined surface may have a curved shape. In the case of the curved shape of the inclined surface, the inclination angle is obtained by integrating the angle formed by the inclined surface 42 and dividing by the integrated profile length.

Next, the dimensions of each slope 42 will be described. In the following description, the normal direction of the reference surface 41 is the x direction, the direction perpendicular to the x direction, and the extending direction of each inclined surface 42 is the y direction, the direction perpendicular to the x direction and the y direction, and a plurality of directions. The direction in which the slopes 42 are arranged is also referred to as the z direction. Each inclined surface 42 extends linearly in the y direction and is displaced from one side in the x direction to the other side in the x direction as it goes from one end in the z direction to the other end in the z direction (for example, in the negative Z direction). It is inclined so as to be displaced in the positive direction.

The inclination angle θ of the inclined surface 42 is set based on the positional relationship between the projector 12, the user 13, and the transparent screen 20, the refractive index of the transparent screen 20, and the like. The reason why the refractive index of the transparent screen 20 is taken into account is that the incident light IL and the reflected light RL are refracted at the boundary between the transparent screen 20 and the atmosphere.

The inclination angle θ of the inclined surface 42 is, for example, 2 ° or more and 45 ° or less, and preferably 5 ° or more and 20 ° or less. The inclination angle θ of the inclined surface 42 is measured in a cross section perpendicular to the y direction (for example, the cross section shown in FIG. 2). The inclination angle θ of the inclined surface 42 is 0 ° when the inclined surface 42 is parallel to the reference surface 41, and 90 ° when the inclined surface 42 is perpendicular to the reference surface 41.

The width W of the slope 42 is 10 μm or more and 500 μm or less. The width W of the slope 42 is a dimension in the z direction of the slope 42 in a cross section perpendicular to the y direction.

The height difference H of the slope 42 is 2 μm or more and 500 μm or less. The height difference H of the slope 42 is a dimension in the x direction of the slope 42 in a cross section perpendicular to the y direction. H, W, and θ have a relationship of H / W = tan θ.

Between the plurality of adjacent slopes 42, a step surface 43 that connects the plurality of adjacent slopes 42 is formed. The step surface 43 is perpendicular to the reference surface 41 in FIG. 1, but may be oblique. In addition to the step surface 43, a parallel surface parallel to the reference surface 41 may be formed between the plurality of adjacent inclined surfaces 42.

The transparent screen 20 further includes an uneven layer 33 that forms unevenness on the slope 42 of the first transparent layer 32 between the first transparent layer 32 and the reflective layer 34. The uneven layer 33 includes particles 37 and a matrix 38.

Particle 37 includes at least one of inorganic particles and organic particles. Examples of the inorganic particle material include silicon dioxide, partial nitride of silicon dioxide, titanium oxide, aluminum oxide, mixed crystal material of silicon dioxide and aluminum oxide, zirconium oxide, and zinc oxide. Examples of the organic particle material include polystyrene resin, acrylic resin, and polyurethane resin.

The matrix 38 includes at least one of an inorganic material and an organic material. Examples of the inorganic material include silicon dioxide, titanium oxide, zirconia oxide, and sodium silicate. Examples of the organic material include polyvinyl alcohol resin, polyvinyl butyral resin, epoxy resin, acrylic resin, polyester resin, polycarbonate resin, melamine resin, polyurethane resin, urethane acrylate resin, and silicone resin. The organic material may be a thermosetting resin, a photocurable resin, or a thermoplastic resin.

The absolute value of the difference in refractive index between the particles 37 and the matrix 38 is preferably as small as possible, for example 0.1 or less, preferably 0.05 or less, more preferably 0.02 or less. Further, the absolute value of the difference in refractive index between the particles 37 and the first transparent layer 32 is preferably as small as possible, for example, 0.1 or less, preferably 0.05 or less, and more preferably 0.02 or less. Furthermore, the absolute value of the difference in refractive index between the matrix 38 and the first transparent layer 32 is preferably as small as possible, for example, 0.1 or less, preferably 0.05 or less, and more preferably 0.02 or less.

The ratio of the particles 37 in the uneven layer 33 is, for example, 1% or more and 80% or less, preferably 5% or more and 60% or less.

The concavo-convex layer 33 has concavo-convex portions on the surface in contact with the reflective layer 34, and has a structure in which convex portions 33a and concave portions 33b are alternately arranged in a cross section perpendicular to the y direction.

The height difference h between the adjacent convex portion 33a and the concave portion 33b is, for example, 1/3 or less of the height difference H of the slope 42. The height difference h between the adjacent convex portion 33a and concave portion 33b is measured in a direction perpendicular to the slope 42 in a cross section perpendicular to the y direction.

The interval w between the plurality of adjacent convex portions 33a is 1/3 or less of the dimension (W / cos θ) in the inclination direction of the inclined surface 42. The interval w between the plurality of adjacent convex portions 33a is measured in a direction parallel to the slope 42 in a cross section perpendicular to the y direction. The interval w between the plurality of adjacent convex portions 33a can be adjusted, for example, by controlling the particle size or particle size distribution of the particles 37, the volume ratio of the particles 37 and the matrix 38, the charging state of the particles 37, or the like.

Regarding the regularity of the concave-convex shape of the concave-convex layer 33, regularity can be easily obtained when the particle size variation of the particles 37 is reduced, and regularity is lost when the particle size variation of the particles 37 is increased, thereby forming random irregularities. it can. Further, by making the total volume of the particles 37 smaller than the volume of the matrix 38, random irregularities can be formed. In particular, the regularity can be reduced by setting the volume of the particles 37 to 100% or less of the volume of the matrix 38.

On the other hand, by imparting regularity to the concavo-convex shape of the concavo-convex layer 33, the light scattering direction can be easily aligned, so that the luminance can be further increased.

The reflective layer 34 has a thickness of, for example, 5 nm or more and 5000 nm or less, and is formed along the unevenness of the uneven layer 33. Therefore, the reflective layer 34 is inclined in the same direction with respect to the reference surface 41 and has a plurality of reflective inclined surfaces 45 that reflect the light of the projected image. Each reflective inclined surface 45 is inclined so as to be away from the reference surface 41 from one end (for example, the lower end) toward the other end (for example, the upper end). The plurality of reflective inclined surfaces 45 are formed in a stripe shape when viewed from the normal direction of the reference surface 41. The stripe line may be a straight line or a curved line. Each reflecting slope 45 extends linearly in the y direction, and is displaced from one side in the x direction to the opposite side in the x direction as it goes from one end in the z direction to the other end in the z direction (for example, as it goes in the negative Z direction). X to be displaced in the positive direction).

The inclination angle of the reflective slope 45 can be represented by the inclination angle θ of the slope 42, and is 2 ° or more and 45 ° or less. The inclination angle of the reflective slope 45 is measured in a cross section perpendicular to the y direction. The inclination angle of the reflective slope 45 is 0 ° when the reflective slope 45 is parallel to the reference plane 41, and 90 ° when the reflective slope 45 is perpendicular to the reference plane 41.

The inclination angle of the reflective slope 45 is set based on the positional relationship between the projector 12, the user 13, and the transparent screen 20, the refractive index of the transparent screen 20, and the like. The reason why the refractive index of the transparent screen 20 is taken into account is that the incident light IL and the reflected light RL are refracted at the boundary between the transparent screen 20 and the atmosphere.

The width of the reflective slope 45 can be represented by the width W of the slope 42, and is 10 μm or more and 500 μm or less. The width of the reflective slope 45 is the dimension of the reflective slope 45 in the z direction in a cross section perpendicular to the y direction. The width W is preferably 15 to 400 μm, more preferably 20 to 150 μm. When the width W is 500 μm or less, it is possible to prevent the reflective slope from being seen by an observer. On the other hand, when the width W is 10 μm or more, it is easy to process the reflective slope.

The height difference of the reflective slope 45 can be represented by the height difference H of the slope 42, and is 2 μm or more and 500 μm or less. The difference in height of the reflective slope 45 is the dimension of the reflective slope 45 in the x direction in a cross section perpendicular to the y direction. The height difference H is preferably 2 to 100 μm, more preferably 2 to 50 μm.

Between the plurality of adjacent reflecting slopes 45, a step surface 46 connecting the plurality of adjacent reflecting slopes 45 is formed. The step surface 46 is perpendicular to the reference surface 41 in FIG. 2, but may be inclined. In addition to the step surface 46, a parallel surface parallel to the reference surface 41 may be formed between the plurality of adjacent reflective inclined surfaces 45.

The reflective inclined surface 45 has irregularities, and has a structure in which convex portions 45a and concave portions 45b are alternately arranged in a cross section perpendicular to the y direction.

The height difference between the adjacent convex portion 45a and the concave portion 45b can be represented by the height difference h between the adjacent convex portion 33a and the concave portion 33b, and is, for example, 1/3 or less of the height difference of the reflecting slope 45. The height difference h between the adjacent convex portion 45a and concave portion 45b is measured in a direction perpendicular to the least square line of the reflective slope 45 in a cross section perpendicular to the y direction. In the present specification, the height difference h is represented by the arithmetic average roughness Ra of the reflecting slope 45.
The surface roughness Ra of the reflective slope 45 is sufficiently shorter than the length L (L = | W / cos θ |) in the tilt direction of the reflective slope 45, for example, 0.01 μm or more and 10 μm or less. In the present specification, the “surface roughness Ra” is an arithmetic average roughness described in Japanese Industrial Standard (JIS B0601). The surface roughness Ra of the reflective slope 45 is measured in the y direction. The arithmetic mean roughness Ra of the reflective slope 45 is not in the z direction but in the y direction so that noise does not occur due to the first transparent layer 32 being formed in a sawtooth shape in a cross section perpendicular to the y direction. taking measurement. Ra is preferably 0.03 μm to 5 μm, more preferably 0.05 μm to 3 μm.

The interval between the plurality of adjacent convex portions 45a can be represented by the interval w between the plurality of adjacent convex portions 33a, and is 1/3 or less of the dimension (W / cos θ) in the inclination direction of the reflective inclined surface 45. The interval between the plurality of adjacent convex portions 45a is measured in a direction parallel to the least square line of the reflecting slope 45 in a cross section perpendicular to the y direction.

As described above, the reflective layer 34 of the present embodiment is inclined in the same direction with respect to the reference plane 41 and has a plurality of reflective inclined surfaces 45 that reflect the light of the projected image. The plurality of reflective inclined surfaces 45 are formed in a stripe shape when viewed from the normal direction of the reference surface 41. Each reflective slope 45 has irregularities and displays an image. Therefore, the reflective inclined surface 45 that displays the image is inclined with respect to the image projection surface 11a that generates the hot spot. The direction in which a bright image is observed is the regular reflection direction of the reflecting slope 45, and the direction in which the hot spot is observed is the regular reflection direction of the image projection surface 11a. Therefore, the direction in which the hot spot is observed and the direction in which the bright image is observed can be separated, and the position where the bright image is observed without observing the hot spot (for example, the position of the user 13 indicated by a solid line in FIG. 1). Can produce.

FIG. 3 is a diagram showing an example of a measuring apparatus that measures the relationship between the incident angle of incident light and the brightness of the transparent screen while maintaining the output angle of the reflected light constant. The incident angle is an inclination angle of the incident direction of incident light with respect to the normal direction of the image projection plane. When the incident direction of incident light coincides with the normal direction of the image projection plane, the incident angle is 0 °. Further, the exit angle refers to an inclination angle of the exit direction of the exit light with respect to the normal direction of the image projection plane. When the emission direction of the emitted light coincides with the normal direction of the image projection plane, the emission angle is 0 °.

As shown in FIG. 3, the luminance meter 51 receives the reflected light RL of the incident light IL incident on the transparent screen 20 and measures the luminance of the transparent screen 20. The luminance meter 51 is fixed in front of the transparent screen 20. The transparent screen 20 is also fixed. On the other hand, the projector 12 is rotatable along an arcuate path 52 so that the incident angle θ1 of the incident light IL can be changed. At this time, the emission angle θ2 of the reflected light RL is kept constant (for example, 0 °).

FIG. 4 is a diagram illustrating an example of a measurement result of the measurement apparatus of FIG. In FIG. 4, the horizontal axis represents the incident angle θ1 of the incident light IL, and the vertical axis represents the value Y ′ obtained by dividing the measurement value Y (cd / m ² ) of the luminance meter 51 by the maximum value. In FIG. 4, the solid line shows the measurement result of the transparent screen 20 of the present embodiment shown in FIG. 2, and the broken line shows the measurement result of the conventional transparent screen 120 shown in FIG.

As can be seen from FIG. 4, in the case of the conventional transparent screen 120, the luminance reaches the maximum value when the incident angle θ1 is 0 °, so the direction in which the hot spot is observed and the direction in which the bright image is observed are separated. I understand that I can't. On the other hand, in the case of the transparent screen 20 of the present embodiment, the luminance becomes the maximum value when the incident angle θ1 is 45 °, so that the direction in which the hot spot is observed and the direction in which the bright image is observed can be separated. Recognize.

FIG. 5 is a diagram showing an example of a measuring apparatus that measures the relationship between the outgoing angle of reflected light and the brightness of the transparent screen while keeping the incident angle of incident light constant. The luminance meter 51 is fixed. On the other hand, the projector 12 can turn along the arcuate path 52 so that the emission angle θ2 of the reflected light RL can be changed. The transparent screen 20 is rotated simultaneously with the turning of the projector 12 so that the incident angle θ1 (see FIG. 3) of the incident light IL is maintained constant (for example, −45 °).

FIG. 6 is a diagram illustrating an example of a measurement result of the measurement apparatus of FIG. In FIG. 6, the horizontal axis represents the emission angle θ2 of the reflected light RL, and the vertical axis represents a value Y ′ obtained by dividing the measured value Y (cd / m ² ) of the luminance meter 51 by the maximum value. In FIG. 6, the solid line indicates the measurement result of the transparent screen 20 of the present embodiment shown in FIG. 2, and the broken line indicates the measurement result of the conventional transparent screen 120 shown in FIG.

As is clear from FIG. 6, in the case of the conventional transparent screen 120, the luminance becomes the maximum value when the emission angle θ2 is the same value as the incident angle θ1 (for example, −45 °). It can be seen that the direction in which bright images are observed cannot be separated. On the other hand, in the case of the transparent screen 20 of the present embodiment, when the emission angle θ2 is 0 ° (that is, when the luminance meter 51 is located in front of the transparent screen 20), the luminance becomes the maximum value, so It can be seen that the observed direction and the direction in which a bright image is observed can be separated.

The full width at half maximum α (see FIG. 6) of the reflected light RL of the transparent screen 20 is preferably at least twice the angle of view β of the projector 12 (see FIG. 7). When the intensity of incident light is uniform in the display area of the transparent screen 20, the difference between the maximum value and the minimum value of the luminance can be suppressed to half or less of the maximum value.

Here, the full width at half maximum α of the reflected light RL is obtained in advance by using the measuring apparatus shown in FIG. 3 to obtain the incident angle θ1max that maximizes the measured value of luminance while fixing the emission angle θ2 to 0 °, and FIG. This means the width of the emission angle θ2 at which the measured value Y is equal to or greater than the half value of the maximum value when the luminance is measured using the measuring apparatus shown while the incident angle θ1 is fixed to θ1max. In FIG. 6, when the incident angle θ1max is −45 ° and the emission angle θ2 is 0 °, the luminance becomes the maximum value.

Further, as shown in FIG. 7, the angle of view β of the projector 12 is defined by two straight lines L1 and L2 that connect both ends P1 and P2 of the image I displayed on the transparent screen 20 and the center P3 of the lens of the projector 12. This is the angle formed by Both ends P1 and P2 of the image I are set so that the line connecting the both ends P1 and P2 passes through the center of the image I and is parallel to the stripes of the reflective slope 45.

(Transparent screen layout)
FIG. 8 is a diagram illustrating an example of a positional relationship between the transparent screen of the video projection matching plate, the projector, and the user as viewed from the front of the vehicle. The image projection matching plate 11 is attached to a window at the front of the vehicle. The transparent screen 20 is provided in the lower part of the window. The projector 12 is provided below the window. The eyes of the user 13 are located at the center in the vertical direction of the window. In this case, as shown in FIG. 8, the plurality of reflective inclined surfaces 45 may form elongated horizontal stripes in the horizontal direction. The user 13 can observe a bright image at a position where the hot spot is not observed.

FIG. 9 is a diagram showing another example of the positional relationship between the transparent screen of the image projection laminated board, the projector, and the user as seen from the front of the vehicle. The image projection matching plate 11 is attached to a window at the front of the vehicle. The transparent screen 20 is provided in the upper part of the window. The projector 12 is provided below the window. The eyes of the user 13 are located at the center in the vertical direction of the window. Also in this case, as shown in FIG. 9, the plurality of reflective inclined surfaces 45 may form elongated horizontal stripes in the horizontal direction. The user 13 can observe a bright image at a position where the hot spot is not observed.

FIG. 10 is a diagram showing still another example of the positional relationship among the transparent screen of the image projection laminated board, the projector, and the user as viewed from the front of the vehicle. The image projection matching plate 11 is attached to a window at the front of the vehicle. The transparent screen 20 is provided at the end of the window in the vehicle width direction. The projector 12 is provided below the window. The eyes of the user 13 are located at the center in the vertical direction of the window. In this case, as shown in FIG. 10, the plurality of reflective inclined surfaces 45 may form vertical stripes that are elongated in the vertical direction. The user 13 can observe a bright image at a position where the hot spot is not observed.

(Transparent screen manufacturing method)
FIG. 11 is a flowchart illustrating a method for manufacturing a transparent screen according to an embodiment. As shown in FIG. 11, the method for manufacturing a transparent screen includes a step S101 of forming a plurality of inclined surfaces 42 inclined in the same direction with respect to the reference surface 41 in the first transparent layer 32, and a step S101 of the plurality of inclined surfaces 42. Each includes step S102 for forming irregularities, step S103 for forming the reflective layer 34 in contact with the irregularities, and step S104 for forming the second transparent layer 35 that fills the irregularities of the reflective layer 34.

FIG. 12 is a diagram illustrating an example of steps for forming a plurality of inclined surfaces in a striped pattern in the first transparent layer. As a method for forming the plurality of inclined surfaces 42 in the first transparent layer 32 in a striped pattern, for example, an embossing method is used as shown in FIG.

The embossing method is a method of transferring the concave / convex pattern of the mold 60 to the first transparent layer 32. The embossing method includes an imprint method. The imprint method is a method in which a resin material to be the first transparent layer 32 is sandwiched between the mold 60 and the base sheet 31, the uneven pattern of the mold 60 is transferred to the resin material, and the resin material is solidified.

In this specification, solidification includes hardening. The solidification method is appropriately selected according to the type of resin material. The kind of the resin material may be any of a photocurable resin, a thermoplastic resin, and a thermosetting resin. The photocurable resin is cured by irradiating light. The thermoplastic resin is melted by heating and solidified by cooling. The thermosetting resin changes from a liquid to a solid by heating. These resin materials may be applied to the base sheet 31 or in the mold 60 in a liquid state. Although it does not specifically limit as a coating method, For example, a spray coat method, a spin coat method, a gravure coat method etc. are used.

Note that a cutting method may be used instead of the imprint method. The cutting method is a method of cutting the first transparent layer 32 with a cutting tool. The cutting tool may be a common one.

FIG. 13 is a diagram illustrating an example of a step of forming irregularities on the slope of the first transparent layer (step S102). As a method for forming irregularities on the slope 42, for example, a spray method is used.

The spray method is a method of forming the uneven layer 33 by spraying a coating liquid onto the slope 42 and solidifying the sprayed liquid. The coating liquid includes particles 37 and a matrix 38, and may further include a solvent that dissolves the matrix 38. The uneven layer 33 forms unevenness on the slope 42. The spray method is suitable for forming the uneven layer 33 having a large area and a uniform area as compared with the spin coating method.

Instead of the spray method, a film forming method may be used in which the coating liquid is applied to the inclined surface 42 and the coating film of the coating liquid is dried and solidified. As a film forming method, a spin coating method, a gravure coating method, or the like may be used.

FIG. 14 is a diagram illustrating an example of steps for forming a reflective layer. As a method for forming the reflective layer 34, for example, a vacuum deposition method or a sputtering method is used. The reflective layer 34 is formed along the unevenness of the uneven layer 33.

FIG. 15 is a diagram illustrating an example of steps for forming the second transparent layer. The second transparent layer 35 is obtained by sandwiching and solidifying a resin material to be the second transparent layer 35 between the reflective layer 34 and the protective sheet 36.

In addition, the transparent screen 20 of this embodiment is the 1st transparent layer 32, the uneven | corrugated layer 33, the reflection layer 34, and the 2nd transparent layer 35 toward the front side from the back side, as shown in FIG.1 and FIG.2. In this order, but the order may be reversed. That is, the transparent screen 20 may have the second transparent layer 35, the reflective layer 34, the uneven layer 33, and the first transparent layer 32 in this order from the rear side to the front side. In the reflective layer 34, the contact surface with the uneven layer 33 and the contact surface with the second transparent layer 35 have the same shape. Therefore, the reflective layer 34 may reflect the light of the projected image on either the contact surface with the uneven layer 33 or the contact surface with the second transparent layer 35.

(Deformation, improvement)
Although the embodiments such as the transparent screen have been described above, the present invention is not limited to the above-described embodiments and the like, and various modifications and improvements are possible within the scope of the gist of the present invention described in the claims. is there.

FIG. 16 is a diagram showing a video display system according to a modification. The video display system 10A of this modification is different from the video display system 10 of the above embodiment in that it includes a transparent screen 20A. Hereinafter, the difference will be mainly described.

The transparent screen 20A of this modification is different from the transparent screen 20 of the above embodiment in that the reflective layer 34A is in contact with the first transparent layer 32A. The transparent screen 20 </ b> A, the first transparent plate 21, and the second transparent plate 22 constitute the video projection matching plate 11 </ b> A.

The first transparent layer 32A has a plurality of inclined surfaces 42A inclined in the same direction with respect to the reference surface 41A. Each inclined surface 42A is inclined so as to be away from the reference surface 41A from one end (for example, the lower end) toward the other end (for example, the upper end). The plurality of inclined surfaces 42A are formed in a stripe shape when viewed from the normal direction of the reference surface 41A. Each slope 42A has irregularities. As a method for forming irregularities on the inclined surface 42A, for example, an etching method or an imprint method is used.

The etching method is a method of forming irregularities on the slope 42A by etching the slope 42A formed by a stamping method or a cutting method. The etching method may be either a physical etching method or a chemical etching method.

The physical etching method includes a blast method. The blast method may be either a drive blast method or a wet blast method. In the case of the drive last method, irregularities are formed on the slope 42A by spraying particles onto the slope 42A. As the particles, for example, alumina particles, silicon carbide particles, zircon particles and the like are used. In the case of the wet blast method, irregularities are formed on the slope 42A by spraying a mixed fluid of particles and liquid onto the slope 42A.

The reflective layer 34A is inclined in the same direction with respect to the reference surface 41A, and has a plurality of reflective inclined surfaces 45A that reflect the light of the projected image. Each reflective inclined surface 45A is inclined so as to be away from the reference surface 41A from one end (for example, the lower end) to the other end (for example, the upper end). The plurality of reflective inclined surfaces 45A are formed in a stripe shape when viewed from the normal direction of the reference surface 41A.

The reflective layer 34A has a thickness of, for example, 5 nm or more and 5000 nm or less, and is formed along the unevenness of the inclined surface 42A. Therefore, each reflective slope 45A has irregularities. The unevenness of the reflective layer 34A is filled with the second transparent layer 35A.

According to this modification, as in the above embodiment, the reflective inclined surface 45A for displaying an image is inclined with respect to the image projection surface 11Aa that generates a hot spot. As a result, the direction in which the hot spot is observed and the direction in which the bright image is observed can be separated, and the position where the bright image is observed without observing the hot spot (for example, the position of the user 13 shown in FIG. 16). Can be produced.

In the above embodiment and the above modification, a resin layer is used as the first transparent layers 32 and 32A, but a glass layer may be used. As a method for forming a plurality of slopes in the glass layer in a striped pattern, for example, a stamping method is used. The embossing method is a method of transferring a concave / convex pattern of a mold onto a glass layer softened at a high temperature.

The first transparent plate 21 may be used as the first transparent layers 32 and 32A. When the first transparent plate 21 is a glass plate, bending and stamping may be performed simultaneously by press molding.

When the first transparent plate 21 is used as the first transparent layer 32, the uneven layer 33 and the reflective layer 34 are formed on the first transparent plate 21. In addition, when the first transparent plate 21 is used as the first transparent layer 32 </ b> A, the reflective layer 34 </ b> A is formed on the first transparent plate 21.

The second adhesive layer 24 may be used as the second transparent layers 35 and 35 </ b> A, and the second transparent plate 22 may be used instead of the protective sheet 36.
Note that a transparent resin material having a ring structure and / or a polyfunctional group may be used as the second transparent layers 35 and 35A. When the transparent resin material is used, since the rigidity and hardness can be imparted to the transparent layer, the handleability of the transparent screen 20 is improved, which is preferable.
Specifically, as the transparent resin material, a transparent resin material containing 10% or more of one or more structures selected from an adamantane skeleton, a tricyclodecane skeleton, and a fluorene skeleton is preferably used.
Moreover, you may use the transparent resin material which provided the hard-coat layer and the anti-reflective film on PET resin as the 2nd transparent layers 35 and 35A. Furthermore, you may provide the half mirror for virtual image formation of a head-up display on PET resin.
When the transparent resin material having sufficient surface hardness and transparency as described above is used as the second transparent layer 35, 35A, the second transparent layer 35, 35A made of the transparent resin material is used for the transparent screen 20. A configuration in which the protective sheet 36, the second adhesive layer 24, and the second transparent plate 22 are not provided may be provided in the outermost layer.

In the above embodiment and the above modification, the step of forming the plurality of inclined surfaces 42 in a striped pattern and the step of forming irregularities on the inclined surfaces 42 are performed in this order, but may be performed simultaneously. For example, in the case of the die pressing method, if the uneven pattern surface of the die 60 is roughened by an etching method in advance, it can be performed simultaneously.

The image projection laminated plates 11 and 11A may further have a functional layer (not shown). Examples of the functional layer include a light reflection preventing layer that reduces reflection of light, a light attenuation layer that attenuates part of light, and an infrared shielding layer that suppresses transmission of infrared light. Furthermore, examples of the functional layer include a functional layer such as a vibration layer that functions as a speaker by applying a voltage and vibrates, and a sound insulation layer that suppresses sound transmission. The number of functional layers and the position of the functional layers are not particularly limited.

Example 1
First, the transparent screen 20A shown in FIG. 16 was produced by the following method.

First, a PET film having a thickness of 0.075 mm was prepared as the base sheet 31 and the protective sheet 36. Further, as the mold 60, a mold (made of nickel chrome) having a plurality of sawtooth-like slopes in cross section on the surface facing the PET film is used, and laser ablation is performed to form unevenness on the slopes. Carried out. In the mold to be the mold 60, when the surface opposite to the surface facing the PET film is a reference surface, all the inclined surfaces are inclined in the same direction at the same angle with respect to the reference surface. When viewed from the normal direction, the slope was striped.

Next, on the base material sheet 31 (PET film), the first transparent layer forming composition containing a UV curable acrylic resin is applied by a die coating method, and the first transparent layer precursor layer is applied. Obtained.

Next, the mold 60 was placed on the first transparent layer precursor layer so that the side on which the inclined surface was formed was in contact with the first transparent layer precursor layer. In this state, the first transparent layer precursor layer is irradiated with 1000 mJ UV light from the opposite side of the mold 60 from the first transparent layer precursor layer as a reference, and the UV curable mold in the first transparent layer precursor layer is irradiated. The acrylic resin was cured to form the first transparent layer 32A.

Thereafter, by removing the mold 60, a laminated body in which the first transparent layer 32A having the slope 42A was formed on the base sheet 31 was obtained. Here, the unevenness of the inclined surface of the mold was transferred onto the inclined surface 42A. The first transparent layer 32A had an inclination angle θ of 14 °, a width W of about 40 μm, and a height difference H of about 10 μm, and had a saw-shaped slope in cross-sectional view. Ra of the slope 42A was 0.39 μm.

Next, the reflective layer 34A was formed on the inclined surface 42A having the unevenness by a sputtering method. Specifically, as the reflective layer 34A, an InZnO ₂ layer (thickness 10 nm), an AgBiNd layer (thickness 10 nm), and an InZnO ₂ layer (thickness 50 nm) were formed in this order. The total thickness of the reflective layer 34A was 70 nm.

Next, a coating solution containing an adhesive layer resin and a diluting solvent was placed on the reflective layer 34A by a die coating method. The resin for the adhesion layer was a cycloolefin resin.

Thereafter, heating was performed at 110 ° C. for 5 minutes to dry the diluted solvent, and an adhesion layer was formed. The thickness of the adhesion layer was 1.5 μm.

Next, a second transparent layer precursor containing a UV curable resin type acrylic resin is applied on the reflective layer 34A on which the adhesion layer is formed by a die coating method. A layer was obtained. Further thereon, a PET film having a thickness of 0.075 mm is stacked as the protective sheet 36, and in this state, 1000 mJ UV light is applied from the PET film side to the second transparent layer precursor with reference to the second transparent layer precursor layer. The layer was irradiated to cure the UV curable resin type acrylic resin in the second transparent layer precursor layer to form the second transparent layer 35A. Thus, a transparent screen 20A was obtained.

Next, the image projection laminated plate 11A shown in FIG. 16 was produced using the transparent screen 20A by the following method.

First, 2 mm thick soda lime glass was prepared as the first transparent plate 21 and the second transparent plate 22. Further, as the first adhesive layer 23 and the second adhesive layer 24, PVB films having a thickness of 30 mil (thickness of about 750 μm) were prepared.

Next, the first transparent plate 21, the first adhesive layer 23, the transparent screen 20, the second adhesive layer 24, and the second transparent plate 22 were laminated in this order to form a laminate.

Next, this laminate was heated at 120 ° C. for 1 hour in a vacuum-packed state. Thereby, the image projection laminated plate 11A was produced.

(Example 2)
The transparent screen 20 shown in FIG. 1 was created by the following method.
As the mold 60, a mold (made of nickel chrome) in which a plurality of sawtooth-like inclined surfaces having the same cross-sectional view as in Example 1 was formed was used in a state where unevenness formation by laser ablation was not performed. In the mold to be the mold 60, when the surface opposite to the surface facing the PET film is a reference surface, all the inclined surfaces are inclined in the same direction at the same angle with respect to the reference surface. When viewed from the normal direction, the slope was striped.

The 1st transparent layer 32 was formed on the 1st substrate sheet 31 (PET film) like Example 1 except having used the metallic mold in the state where unevenness formation is not performed as type 60. The first transparent layer 32 had an inclination angle θ of 14 °, a width W of about 40 μm, and a height difference H of about 10 μm, and had a saw-shaped slope in cross-sectional view.

Next, a spray liquid for forming an uneven layer on the first transparent layer 32 was prepared. Using a dispersion liquid (silica particles: 20 wt%, acrylic monomer: 40 wt%, PGMEA solvent: 40 wt%) in which silica particles having an average particle diameter of 1.6 μm are dispersed in an acrylic resin composition, MEK is added as a dilution solvent. Using a solution diluted 5 times, spray coating was performed on the first transparent layer 32. After coating, the substrate was dried in an oven at 80 ° C. for 5 minutes, and then irradiated with 1000 mJ of UV light to cure the acrylic resin containing the silica particles, thereby forming an uneven layer. The thickness of the uneven layer 33 was 3 μm, and its Ra was 0.33 μm.

Next, in the same manner as in Example 1, a reflective layer 34, an adhesion layer, and a second transparent layer 35 were formed in this order on the uneven layer 33. Thereby, the transparent screen 20 was obtained. Thereafter, the image projection laminated plate 11 was produced in the same manner as in Example 1 using the transparent screen 20.

(Example 3)
The transparent screen 20A shown in FIG. 16 was created by the following method.
As the mold 60, a mold (made of nickel chrome) in which a plurality of sawtooth-like inclined surfaces having the same cross-sectional view as in Example 1 was formed was used in a state where unevenness formation by laser ablation was not performed. In the mold to be the mold 60, when the surface opposite to the surface facing the PET film is a reference surface, all the inclined surfaces are inclined in the same direction at the same angle with respect to the reference surface. When viewed from the normal direction, the slope was striped.

A first transparent layer 32A was formed on the first base sheet 31 (PET film) in the same manner as in Example 1 except that a mold without forming irregularities was used as the mold 60. The first transparent layer 32A had an inclination angle θ of 14 °, a width W of about 40 μm, and a height difference H of about 10 μm, and had a saw-shaped slope in cross-sectional view.

Next, a mixed liquid mixed with ultrapure water so that the content of alumina particles having an average particle diameter of 3 μm is 13 wt% is prepared as a blast liquid, and is sprayed on the first transparent layer 32A having the slope 42A. Then, irregularities were formed on the slope 42A by a physical etching method using wet blasting. Ra of the slope 42A after the blast treatment was 0.11 μm.

Next, a reflective layer 34A was formed on the sloped surface 42A having the irregularities by a sputtering method. The reflective layer 34A was a layer made of Al, and its thickness was 15 nm.

Next, a second transparent layer 35A was formed on the reflective layer 34 in the same manner as in Example 1. Thus, a transparent screen 20A was obtained. Thereafter, an image projection laminated plate 11A was produced in the same manner as in Example 1 using the transparent screen 20A.

(Comparative Example 1)
In Comparative Example 1, the first transparent layer 132 was formed on the first base sheet in the same manner as in Example 1 except that a sand blast film in which random irregularities were formed on a flat surface by sand blasting was used as the mold 60. (See FIG. 17). Ra of the surface of the first transparent layer 132 to which the unevenness was transferred was about 0.2 μm. Then, the process similar to Example 1 was implemented and the transparent screen 120 shown in FIG. 17 was obtained. Thereafter, using the transparent screen 120, an image projection laminated plate was produced in the same manner as in Example 1.

(Comparative Example 2)
In Comparative Example 2, a transparent screen was obtained in the same manner as in Example 3 except that the formation of irregularities by wet blasting was omitted from Example 3. Using the obtained transparent screen, an image projection laminated plate was produced in the same manner as in Example 1.

(Evaluation)
Various evaluations shown below were performed using the image projection laminated plates according to Examples 1 to 3 and Comparative Examples 1 and 2.

(Measurement of haze)
The haze of the image projection laminated plates according to Examples 1 to 3 and Comparative Examples 1 and 2 was measured. The measurement was carried out using a D65 light source described in JIS Z8720: 2012 using a haze meter based on JIS K7136.

(Measurement of luminance characteristics of image projection laminated plate)
The luminance characteristics of the image projection laminated plates according to Examples 1 to 3 and Comparative Examples 1 and 2 were measured using the measurement apparatus shown in FIG. 5 while fixing the incident angle θ1 to θ1max. Note that the variation in θ1max is due to the difference in the method of manufacturing the transparent screen. The measurement results are shown in FIGS. 18A, 18B, 19A, 19B, 20A, 20B, 21A, 21B, 22A and 22B. In these drawings, the horizontal axis represents the emission angle θ2 of the reflected light RL, and the vertical axis represents the value Y ′ obtained by dividing the measured value Y (cd / m ² ) of the luminance meter 51 by the maximum value. In addition, Y 'shown in these figures removes the component reflected in the front surface of the transparent screen.
According to the first to third embodiments, as shown in FIGS. 18 to 20, when the emission angle θ2 is 0 ° (that is, when the luminance meter 51 is located in front of the image projection laminated plate), the luminance becomes the maximum value. It was. Therefore, it was found that the direction in which the hot spot is observed and the direction in which the bright image is observed can be separated.
On the other hand, according to Comparative Example 1, as shown in FIG. 21, when the exit angle θ2 is the same value as the incident angle θ1 (for example, −45 °), the luminance becomes the maximum value. Therefore, it was found that the direction in which the hot spot is observed and the direction in which the bright image is observed cannot be separated.
In Comparative Example 2, bright lines were generated in a line shape, and no image was seen. According to Comparative Example 2, as shown in FIG. 22, when the emission angle θ2 is 0 ° (that is, when the luminance meter 51 is located in front of the image projection laminated plate), the luminance becomes the maximum value. Therefore, it was found that the direction in which the hot spot is observed and the direction in which the bright image is observed can be separated.

(Measurement of full width half maximum α of image projection laminated plate)
The full width at half maximum α was obtained from the luminance characteristics shown in FIGS. When this value is 7 ° or more, a viewing angle as a screen can be secured, which is preferable in use.

(Summary of experiment)
Table 1 shows experimental conditions and experimental results. In Table 1, “A” means that the direction in which the hot spot is observed can be separated from the direction in which the bright image is observed, and “B” means that the direction in which the hot spot is observed is bright. This means that the direction in which the image is observed could not be separated.

　本出願は、２０１７年１月１３日に日本国特許庁に出願された特願２０１７－００４３０８号に基づく優先権を主張するものであり、特願２０１７－００４３０８号の全内容を本出願に援用する。

This application claims priority based on Japanese Patent Application No. 2017-004308 filed with the Japan Patent Office on January 13, 2017. The entire contents of Japanese Patent Application No. 2017-004308 are incorporated herein by reference. To do.

DESCRIPTION OF SYMBOLS 10 Image display system 11 Image | video projection laminated plate 12 Projector 13 User 20 Transparent screen 21 1st transparent plate 22 2nd transparent plate 31 Base material sheet 32 1st transparent layer 33 Concavity and convexity layer 34 Reflective layer 35 2nd transparent layer 36 Protective sheet 37 Particle 38 Matrix 41 Reference surface 42 Slope 45 Reflective slope

Claims (14)

A first transparent layer, a reflective layer that reflects light of a projected image, and a second transparent layer provided on the opposite side of the first transparent layer with respect to the reflective layer, Transparent screen,
The reflective layer has a plurality of reflective inclined surfaces that are inclined in the same direction with respect to the reference surface and reflect the light, when a surface of the first transparent layer opposite to the reflective layer is used as a reference surface. And
The plurality of reflective slopes each have irregularities, and are formed in a striped shape when viewed from the normal direction of the reference surface. The first transparent layer has a plurality of inclined surfaces inclined in the same direction with respect to the reference surface,
The plurality of slopes are formed in stripes when viewed from the normal direction of the reference plane,
The transparent screen further includes a concavo-convex layer that forms undulations on the slope of the first transparent layer between the first transparent layer and the reflective layer,
The uneven layer includes particles and a matrix, and has an uneven surface on the surface in contact with the reflective layer,
The transparent screen according to claim 1, wherein the reflective slope is formed along the unevenness of the uneven layer. The first transparent layer has a plurality of inclined surfaces inclined in the same direction with respect to the reference surface,
Each of the plurality of slopes has irregularities, and is formed in a stripe shape when viewed from the normal direction of the reference surface,
The transparent screen according to claim 1, wherein the reflective slope is formed along irregularities of the slope. The transparent screen according to any one of claims 1 to 3, wherein the reflective layer includes at least one of a metal layer and a dielectric layer. The transparent screen according to any one of claims 1 to 4, wherein the haze of the transparent screen is 10% or less. A transparent screen according to any one of claims 1 to 5;
A first transparent plate provided on one side of the transparent screen;
And a second transparent plate provided on the opposite side of the transparent screen. The image projection matching plate according to claim 6, wherein the image projection matching plate is used as a window plate of a vehicle. A transparent screen according to any one of claims 1 to 5;
An image display system comprising: a projector that projects an image on the transparent screen. The video display system according to claim 8, wherein the full width at half maximum of the reflected light of the transparent screen is at least twice the angle of view of the projector. A first transparent layer, a reflective layer that reflects light of a projected image, and a second transparent layer provided on the opposite side of the first transparent layer with respect to the reflective layer, A method for producing a transparent screen capable of visually recognizing
Forming a plurality of slopes in the first transparent layer in a striped pattern inclined in the same direction with respect to a reference plane;
Forming irregularities on each of the plurality of slopes;
Forming the reflective layer in contact with the irregularities;
Forming a second transparent layer that fills the unevenness of the reflective layer. The method for producing a transparent screen according to claim 10, wherein the method of forming irregularities on the slope is a spray method in which a liquid containing particles and a matrix is sprayed on the slope. The method for producing a transparent screen according to claim 10, wherein the method of forming irregularities on the slope is an etching method for etching the slope. The method for producing a transparent screen according to any one of claims 10 to 12, wherein the method of forming the inclined surface is an embossing method in which an uneven pattern of a mold is transferred to the first transparent layer. The method for producing a transparent screen according to any one of claims 10 to 12, wherein the method of forming the slope is a cutting method of cutting the first transparent layer with a cutting tool.

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