Screen and method of manufacturing the same

Abstract

To avoid the increase of the cost of a metallic mold and the complication of a screen manufacturing process for securing the high luminance and the visual field angle of a screen.SOLUTION: The screen 10 includes a first base material layer (first layer 11), a Fresnel lens layer (second layer 12), a reflective layer (third layer 13), an optical transparent layer (fourth layer 14), and a second base material layer (fifth layer 15) in this order from the image source side Z1. The Fresnel lens layer includes an array of unit convex shapes 30 that are convex toward the Z2 on the back surface side. The surface of the unit convex shape 30 is a rough surface, and a reflection layer is formed on the rough surface. The reflection layer is a coating film layer in which thin pieces 40 reflecting the image light are dispersed. In the reflection layer, at least a part of the thin pieces 40 is arranged in a state where the orientation is disturbed along the unevenness of the rough surface, and diffuses and reflects a part of the image light. When the reflective layer is formed, the surface of the unit convex shape 30 is eroded and roughened by a solvent contained in the coating film material so that the orientation of the thin piece 40 is moderately disturbed.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a screen for displaying an image projected from an image source, and a method for manufacturing the same. [Background technology]

[0002] Conventionally, a transmissive screen, in which light from the rear side of the screen passes through the screen, has been used as a screen for displaying an image projected from an image source. This type of screen allows the image projected from the image source to be viewed superimposed on the scenery behind the screen. It also ensures brightness by transmitting light and illumination from the rear side of the screen. For example, when installed on a glass surface, the image can be displayed on the glass surface, and when not in use, the view and light from the glass can be unobstructed.

[0003] Patent Document 1 describes this type of screen. The screen in Patent Document 1 has five layers stacked, in order from the image source side: a base layer, a first optically transparent layer, a reflective layer, a second optically transparent layer, and a protective layer. Unit optical shapes with triangular cross sections that constitute Fresnel lenses are arranged on the surface of the first optically transparent layer opposite the image source (the rear side). A reflective layer is formed on the surface of the unit optical shapes. The second optically transparent layer is a layer that fills in the irregularities of the unit optical shapes.

[0004] In Patent Document 1, a molding die having a finely textured surface is used to form the first optical transparent layer. This results in a finely textured surface on the unit optical shape, which has a triangular cross section. The reflective layer is formed on the surface of the unit optical shape by vapor deposition, resulting in a layer with a finely textured surface. This allows the reflective layer to diffusely reflect a portion of the image light, thereby widening the range of angles at which the image light is emitted from the screen. This widens the range of angles at which a bright image can be viewed, thereby widening the viewing angle. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6642043 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, to form a reflective layer with the fine unevenness necessary for diffuse reflection, plating or etching is performed on the mold surface used to manufacture the Fresnel lens (first optical transparent layer). This requires additional processing of the mold, which increases the cost of the mold. Furthermore, when it becomes necessary to adjust the fine unevenness, which is a parameter that affects the degree of scattering in diffuse reflection, the mold must be changed, which means that adjusting the degree of scattering is costly and time-consuming.

[0007] On the other hand, by subjecting the Fresnel lens after demolding to a roughening treatment such as blasting, it is possible to form a finely textured shape on the surface on which the reflective layer is formed. In this case, there is no need to subject the molding die to plating or etching. However, an additional processing step must be performed on the Fresnel lens after demolding. This increases the number of steps, requires additional processing equipment, and complicates the screen manufacturing process.

[0008] Furthermore, in Patent Document 1, a reflective layer is formed by depositing a reflective material on the surface of a Fresnel lens, and with this method of forming a reflective layer, it is difficult to efficiently mass-produce, produce large screens, or produce to order with various specifications.

[0009] In view of the above problems, an object of the present invention is to propose a screen configuration and a manufacturing method thereof that can achieve high screen brightness and a wide viewing angle, while avoiding increases in mold costs and complication of the screen manufacturing process, and that is suitable for mass production and various types of production, including large-scale production. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, one embodiment of the screen of the present invention is a screen into which image light is incident, comprising: a light-transmitting first base material layer; a Fresnel lens layer laminated on the first base material layer and having an arrangement of unit convex shapes that are convex on the opposite side to the first base material layer; a reflective layer laminated on the surface of the unit convex shapes and made of a coating layer containing flakes that reflect the image light; and an optically transparent layer laminated on the reflective layer from the opposite side to the first base material layer and filling in the unevenness of the unit convex shapes, wherein the surface of the unit convex shapes has a rough surface in the area where the reflective layer is formed, and the reflective layer is characterized in that some of the flakes are arranged in a disordered orientation along the unevenness of the rough surface, thereby diffusively reflecting some of the image light.

[0011] Furthermore, one aspect of the method for manufacturing a screen according to the present invention is a method for manufacturing a screen comprising a Fresnel lens layer in which unit convex shapes onto which image light is incident are arranged, and a reflective layer formed on the surface of the unit convex shapes, characterized in that a coating material containing a volatile solvent and flakes that reflect the image light is applied to the surface of the unit convex shapes, and while the solvent is evaporating, the surface of the unit convex shapes is eroded by the solvent and transformed into a rough surface, and as the solvent erodes and transforms the surface into a rough surface, some of the flakes are arranged in a disordered orientation along the unevenness of the rough surface, thereby forming the reflective layer.

[0012] The screen and its manufacturing method of this embodiment use a coating layer containing flakes that reflect image light as a reflective layer. The coating layer can be manufactured using wet coating technology, allowing for stable production regardless of the screen production volume or size, facilitating mass production and large-scale production. Furthermore, the irregularities in the rough surface increase the scattered light by disrupting the orientation of the flakes, thereby achieving high brightness and a wide viewing angle for the screen. Furthermore, the rough interface between the Fresnel lens layer, the reflective layer, and the optically transparent layer makes the interface less susceptible to peeling, resulting in high durability.

[0013] Furthermore, in the screen and manufacturing method of this embodiment, since the reflective layer is a coating layer, the surface of the Fresnel lens layer is eroded by the attacking force of the solvent contained in the coating material, and a rough surface can be formed simultaneously when the reflective layer (coating layer) is formed. This makes it possible to avoid increases in mold costs and complication of the screen manufacturing process. Furthermore, by selecting and blending the solvent, the surface of the Fresnel lens layer can be eroded appropriately to form a rough surface with a desired roughness. This makes it possible to easily adjust the roughness of the rough surface, which is a parameter that affects the viewing angle.

[0014] In the screen of the above embodiment, the reflective layer is preferably a semi-transmissive reflective layer that transmits a portion of incident light. In this case, light from the rear side of the screen is transmitted through the screen, allowing it to be used as a transmissive screen. In addition, the transmittance can be adjusted by selecting and blending the flakes.

[0015] In the screen of the above aspect, the difference in refractive index between adjacent layers of the Fresnel lens layer, the reflective layer, and the optically transparent layer is preferably within 0.05. This allows light from the rear side of the screen to pass through with almost no refraction. Therefore, a transparent screen that allows the rear side to be seen through can be formed.

[0016] In the screen of the above aspect, the reflective layer contains a bleed component dissolved from the resin forming the Fresnel lens layer. The mixing of the bleed component into the reflective layer means that the solvent contained in the coating material has an attacking force that corrodes the resin, and the solvent corrodes the surface of the Fresnel lens layer, forming a rough surface. By utilizing the attacking force of the solvent, it is possible to form a rough surface simultaneously when forming the coating layer, without separately performing a roughening step on the molding die or the Fresnel lens layer.

[0017] In the screen of the above aspect, the reflective layer may contain a binder resin, and the flakes may be dispersed in the binder resin. Furthermore, in the method for manufacturing a screen of the above aspect, the coating material may contain a binder resin. In this case, the properties of the reflective layer can be adjusted by selecting the binder resin. For example, by selecting the binder resin so as to eliminate the difference in refractive index between the Fresnel lens layer and the optically transparent layer, incident light can be transmitted without being refracted at the interface.

[0018] In the screen of the above embodiment, the reflective layer may not contain a binder resin, and the flakes may be attached to the rough surface via the bleeding component. Furthermore, in the method for manufacturing a screen of the above embodiment, the coating material may not contain a binder resin, and the flakes may be attached to the rough surface via the bleeding component dissolved from the resin forming the unit convex shapes. In this way, when the coating material does not contain a binder resin, the flakes adhere to the rough surface due to the adhesive force of the bleeding component dissolved by the attacking force of the solvent. Therefore, the flakes are arranged in a disordered state along the irregularities, increasing the scattered light.

[0019] In the screen of the above embodiment, the half-brightness angle θ, which is the amount of change in angle from the angle at which the luminance of the emitted light reflected by the reflective layer is at its maximum to the angle at which the luminance of the emitted light is half of the maximum, is 10°≦θ≦14°. Since the half-brightness angle θ represents the viewing angle, the screen of this embodiment can achieve a wide viewing angle.

[0020] In the screen of the above aspect, the thin flakes are preferably aluminum-deposited flakes. Aluminum has high reflectivity, which can increase scattered light. Therefore, even though it is a transmission screen, it is possible to achieve high brightness and ensure a wide viewing angle.

[0021] In the screen of the above aspect, it is preferable that a light-transmitting second base layer be laminated on the optically transparent layer from the side opposite to the Fresnel lens layer, thereby protecting the optically transparent layer and increasing durability.

[0022] In the screen manufacturing method of the above aspect, the coating material preferably has a ratio of the solvent content to the flake content of 1:1, which is 10 or more. With such a content ratio, the surface of the Fresnel lens layer can be eroded and appropriately roughened, thereby achieving a wide viewing angle.

[0023] In the method for manufacturing a screen according to the above aspect, in the step of forming the Fresnel lens layer, it is preferable to supply a UV-curable resin material to the mold surface on which the inverted shapes of the unit convex shapes are arranged, and to expose the resin material to UV light while applying pressure to the resin material via a UV-transmitting base film to cure the resin material, and then to release the resin material from the mold surface. In this way, when the Fresnel lens layer is formed by 2P molding, it is possible to suppress inhibition of crosslinking by oxygen in the UV curing process and to enhance toughness. [Effects of the Invention]

[0024] According to the present invention, it is possible to avoid an increase in mold costs and a complication of the screen manufacturing process in order to realize high brightness and a wide viewing angle of the screen, and it is possible to reduce the parameters that affect the viewing angle. The roughness of the rough surface, which is the data, can be easily adjusted. Furthermore, peeling at the interfaces between the Fresnel lens layer, reflective layer, and optically transparent layer is unlikely to occur, resulting in high durability. Furthermore, because the reflective layer is a coating layer, it can be manufactured stably regardless of the production volume or size of the screen, making mass production and upsizing easy. [Brief explanation of the drawings]

[0025] [Figure 1] 1A and 1B are explanatory diagrams showing a usage state of a screen according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the screen shown in FIG. [Figure 3]FIG. 3 is an explanatory diagram of the manufacturing process of the second layer (Fresnel lens layer). [Figure 4] 3A and 3B are a cross-sectional view and a partially enlarged view of a third layer (reflective layer). [Figure 5] FIG. 10 is an explanatory diagram of a manufacturing process for the third layer (reflective layer). [Figure 6] 10 is a graph showing the relationship between the luminance of light emitted from a screen and the emission angle. [Figure 7] 1 is a scanning electron microscope (SEM) photograph of the third layer (reflective layer) taken in plan view. [Figure 8] 1 is a scanning electron microscope (SEM) photograph showing the cross-sectional structure of a screen. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0027] (Video display device) Fig. 1 is an explanatory diagram that schematically shows a usage state of a screen 10 according to the present invention. As shown in Fig. 1, an image display device 1 includes a screen 10 and an image source 20. The Z direction is the normal direction of the screen 10. In the following description, the side of the screen 10 from which image light L is incident, in other words, the side of the screen 10 on which the image source 20 is arranged, is referred to as the image source side Z1. The side of the screen 10 opposite to the image source side Z1 is referred to as the back side Z2.

[0028] As shown in FIG. 1, the screen 10 reflects and emits image light L projected from the image source 20. Therefore, when an observer 2 looks from the image source side Z1, an image is displayed on the surface of the screen 10. In the example shown in FIG. 1, the image source 20 is disposed outside the range directly facing the screen 10, and projects the image light L obliquely onto the screen 10. For example, a short-focus projector can be used as such an image source 20. Note that the arrangement of the image source 20 is not limited to the arrangement shown in FIG. 1.

[0029] The screen 10 is a transmissive screen that transmits light L2 from the rear side Z2 of the screen 10. Therefore, when viewed from the image source side Z1, the image displayed on the screen 10 appears to be superimposed on objects and scenery on the rear side of the screen 10.

[0030] (Cross-sectional structure of the screen) Fig. 2 is a cross-sectional view of the screen 10 shown in Fig. 1. Note that Fig. 2 is a schematic diagram showing the cross-sectional configuration of the screen 10, and the thickness of each layer and the actual size and shape of the optical shape (unit convex shape 30 described later) may differ from those shown in Fig. 2.

[0031] As shown in FIG. 2, the screen includes a first layer 11, a second layer 12, a third layer 13, a fourth layer 14, and a fifth layer 15. The first layer 11, the second layer 12, the third layer 13, the fourth layer 14, and the fifth layer 15 are stacked in this order from the image source side Z1 toward the rear side Z2. Each layer adheres closely to the adjacent layer. The appropriate thickness of each layer is 50 um to 5 mm for the first layer 11, 10 um to 400 um for the second layer 12, 500 nm to 30 um for the third layer 13, 10 um to 400 um for the fourth layer 14, and 50 um to 10 mm for the fifth layer 15. Each layer will be described in detail below.

[0032] (1st layer: 1st base material layer) The first layer 11 is a first base material layer made of a light-transmitting base material. In this embodiment, the first layer 11 is made of a transparent resin. For example, the first layer 11 is made of a transparent resin such as PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), MS (methyl methacrylate-styrene), or PP (polypropylene). The first layer 11 is a layer that serves as a supporting base material for the second layer 12.

[0033] (Second layer: Fresnel lens layer) The second layer 12 is a Fresnel lens layer in which a Fresnel lens is formed on the surface opposite to the first layer 11. A plurality of unit convex shapes 30 that are convex toward the back side Z2 are arranged on the surface of the back side Z2 of the second layer 12. The second layer 12 is made of, for example, a transparent UV-curable resin. The second layer 12 is a circular Fresnel lens layer. Therefore, the planar shape of each unit convex shape 30 when viewed from the Z direction is arc-shaped. When viewed from the Z direction, the plurality of unit convex shapes 30 are arranged concentrically around one point.

[0034] As shown in FIG. 2, each of the multiple unit convex shapes 30 has a first surface 31 that is inclined with respect to the normal direction (Z direction) of the screen 10, and a second surface 32 that is inclined with respect to the first surface 31. In the example shown in FIG. 2, the inclination angle of the first surface 31 with respect to the Z direction is greater than 45°. The inclination angle of the second surface 32 with respect to the Z direction is smaller than the inclination angle of the first surface 31 with respect to the Z direction. As shown in FIG. 2, in this embodiment, the cross-sectional shape of the unit convex shape 30 is a right triangle, and the second surface 32 is a surface parallel to the Z direction. Therefore, the image light L projected from the image source 20 is incident on the first surface 31.

[0035] In the example shown in FIG. 2, the cross-sectional shapes of the multiple unit convex shapes 30 in the second layer 12 increase in size as they move away from the image source 20, and the height of the unit convex shapes 30 in the Z direction increases as they move away from the image source 20. As described above, the multiple unit convex shapes 30 are arc-shaped with a single point as their center, and the cross-sectional shapes of the unit convex shapes 30 increase in size and the arrangement pitch increases as they move away from the center of the arc. An appropriate arrangement pitch for the unit convex shapes 30 is 20 μm to 250 μm. The appropriate shape of the unit convex shapes 30 can be determined using the positional relationship between the screen 10, the image source 20, and the viewer 2 shown in FIG. 1 and the refractive index of each layer of the screen 10 as parameters. For example, when setting the inclination angle ap of the first surface 31 of the unit convex shape 30 shown in Figure 2, the inclination angle ap can be calculated and determined so that the image light L1 incident on the screen 10 from diagonally below is refracted at the interface it passes through before reaching the third layer 13 (reflective layer), then specularly reflected at the first surface 31, and refracted again at the interface before exiting the screen 10, so that the direction of the exiting light L1 is the direction from the exit position toward the observer 2.

[0036] The cross-sectional shape and arrangement pitch of the multiple unit convex shapes 30 are not limited to the shapes described above. For example, the cross-sectional shape of each unit convex shape 30 does not have to be a right-angled triangle. That is, the second surface 32 may be a surface inclined with respect to the Z direction. Furthermore, the multiple unit convex shapes 30 may have the same cross-sectional shape and a constant arrangement pitch. Furthermore, the planar shape of the multiple unit convex shapes 30 as viewed from the Z direction may be linear rather than arc-shaped. That is, the second layer 12 may be a linear Fresnel lens layer.

[0037] 3 is an explanatory diagram of the manufacturing process of the second layer 12 (Fresnel lens layer). As will be described below, when manufacturing the screen 10 of this embodiment, a laminate 33 is manufactured by bonding the first layer 11 and the second layer 12 by 2P molding. As shown in FIG. 3, the 2P molding uses a molding die having a mold surface 34 on which the inverted shape of the unit convex shape 30 is formed, and a base film 35 made of the resin that constitutes the first layer 11.

[0038] First, as shown in the left diagram of FIG. 3, uncured resin material 36 is supplied to a mold surface 34. For example, For example, resin material 36 is applied to mold surface 34. Next, as shown in the center of Fig. 3, base film 35 is brought into close contact with resin material 36, and resin material 36 is cured while being pressed through base film 35.

[0039] In this embodiment, a UV-curable resin is used as the resin material 36, and UV light is irradiated onto a base film 35 that transmits UV light to expose and harden the resin material 36. A Fresnel lens layer is formed by hardening the resin material 36, and the Fresnel lens layer is bonded to the base film 35. This forms the laminate 33. Thereafter, as shown in the right diagram of FIG. 3, the laminate 33 is released from the mold surface 34. Immediately after release from the mold surface 34, the surfaces (first surface 31 and second surface 32) of each unit convex shape 30 are flat.

[0040] The second layer 12 may be made of a resin other than the UV-curable resin. When a resin other than the UV-curable resin is used, another curing process may be performed instead of the UV light exposure process in the pressure curing step of FIG.

[0041] (3rd layer: reflective layer) FIG. 4 is a cross-sectional view of the third layer 13 (reflective layer) and a partially enlarged view thereof. The third layer 13 is a reflective layer that reflects image light L. As shown in FIG. 2, image light L incident on the screen 10 passes through the first layer 11 and the second layer 12 and is reflected by the third layer 13. As described above, the screen 10 is a transmissive screen, and the third layer 13 is a semi-transmissive reflective layer that transmits a portion of the incident light. Furthermore, as will be described later, the third layer 13 specularly reflects a portion of the incident light and diffusely reflects a portion of the incident light. Therefore, the outgoing light L1 that exits the screen 10 includes scattered light.

[0042] The third layer 13 is a coating layer containing flakes 40 that reflect the image light L. The third layer 13 is formed on the surface of the unit convex shapes 30 that constitute the Fresnel lens. As shown in FIG. 2 , in the screen 10, the third layer 13 is formed on the surface of the rear side Z2 of the second layer 12 over the entire area where the unit convex shapes 30 are formed.

[0043] The third layer 13 only needs to be formed in at least the range where the image light L is incident, and does not need to be formed over the entire surface of each unit convex shape 30. For example, as shown in Fig. 2, in the case of a screen 10 that is used in such a manner that the image light L is incident on the first surface 31 of each unit convex shape 30 but not on the second surface 32, the third layer 13 only needs to be formed on at least the first surface 31, and the third layer 13 may or may not be formed on the second surface 32.

[0044] As shown in the partially enlarged view of Figure 4, flakes 40 are dispersed within the third layer 13. On the surface of each unit convex shape 30, the area where the third layer 13 is formed is a matte-like rough surface with a moderate amount of fine unevenness. The third layer 13 is a coating layer that adheres to the rough surface. Therefore, some of the flakes 40 are not oriented uniformly, and are arranged in a moderately disordered state along the unevenness of the rough surface. The image light L incident on the screen 10 is reflected by the flakes 40 arranged within the third layer 13 and emitted toward the image source 20. However, because the light is reflected by the disordered flakes 40, the emitted light L1 contains a moderate amount of scattered light.

[0045] As shown in the partially enlarged view of Figure 4, the third layer 13 has regions where multiple flakes 40 overlap, but the flakes 40 are arranged sporadically in a planar view. Therefore, the third layer 13 has transparent regions C where no flakes 40 are arranged. This allows the third layer 13 to transmit part of the incident light and reflect part of it. Furthermore, light from the rear side Z2 of the screen 10 passes through the screen 10. Note that Figure 4 is a schematic diagram of the flakes 40 dispersed within the third layer 13, and the shape, size, and degree of dispersion of the actual flakes 40 may differ from those shown in Figure 4. good.

[0046] The flakes 40 are aluminum vapor-deposited flakes. For example, fine aluminum flakes used as a pigment in metallic paints can be used as the flakes 40. It is preferable to use aluminum flakes with a planar size of 0.3 μm to 100 μm and a thickness of 20 nm to 300 nm (particle size distribution D50). The flakes 40 are not limited to aluminum vapor-deposited flakes as long as they are made of a material with high reflectivity.

[0047] 5 is an explanatory diagram of the manufacturing process of the third layer 13 (reflective layer). As described above, the third layer 13 is a coating layer, and therefore a coating material 41 containing flakes 40 is applied to the surface of the unit convex shape 30 after demolding. As shown in the upper and center diagrams of FIG. 5, before and immediately after application of the coating material 41, the surface of the unit convex shape 30 is a flat surface formed by the mold surface 34.

[0048] For example, ink containing aluminum vapor-deposited flakes as a pigment can be used as the coating material 41. The coating material 41 is applied by wet coating technology using a roll coater, gravure coater, flexo coater, or the like. This allows an appropriate amount of coating material 41 to be evenly applied to the surface of the unit convex shape 30.

[0049] The coating material 41 contains at least a volatile solvent and flakes 40, but may also contain other components. For example, it may contain a binder resin. The binder resin may be a thermoplastic resin or a thermosetting resin. When a thermosetting resin is used as the binder resin, a curing agent is added. It may also contain other additives (auxiliaries). For example, it may contain additives to adjust viscosity and other properties.

[0050] After the coating material 41 is applied, the attacking force of the solvent erodes the resin that makes up the unit convex shapes 30, until the solvent in the coating material 41 evaporates and disappears, and the surface of the unit convex shapes 30 becomes rough (see the lower diagram in Figure 5). At this time, bleeding components are dissolved from the UV-curable resin due to the corrosion of the solvent, and the bleeding components are mixed into the third layer 13. The bleeding components are mixed into at least the boundary between the third layer 13 and the surface of the unit convex shapes 30.

[0051] As shown in the lower diagram of Figure 5, the third layer 13 becomes thinner as the solvent evaporates and disappears. If the coating material 41 contains a binder resin, the binder resin does not disappear, and therefore, as shown in the lower diagram of Figure 5, the third layer 13 becomes a layer containing the binder resin, with flakes 40 dispersed within the layer. Note that, like Figure 4, Figure 5 schematically shows the flakes 40 dispersed within the third layer 13 and the rough surface formed by solvent erosion, and the actual shape of the rough surface and the shape, size, and degree of dispersion of the flakes 40 may differ from those shown in Figure 5.

[0052] If the coating material 41 does not contain a binder resin, the bleeding component adheres to the flakes 40, and the adhesiveness of the bleeding component causes the flakes 40 to stick to the roughened surface of the unit convex shape 30. Alternatively, the bleeding effect causes the surface of the unit convex shape 30 to become adhesive, causing the flakes 40 to stick. This forms a third layer 13 that does not contain a binder resin.

[0053] The coating material 41 is used with the solvent content adjusted to 10 or more parts per part of the flakes 40. This allows the attacking power of the solvent to be exerted, eroding the surface of the unit convex shapes 30 and roughening it appropriately.

[0054] (4th layer: optically transparent layer) The fourth layer 14 is an optically transparent layer that fills the unevenness of the unit convex shape 30 on the surface of which the third layer 13 is formed. The fourth layer 14 is made of an optically transparent resin, such as an OCR (Optically Clear Resin) resin. For example, the fourth layer 14 can be formed by applying and curing a transparent UV-curable adhesive.

[0055] The refractive index n4 of the resin constituting the fourth layer 14 is equal to the refractive index n2 of the resin constituting the second layer 12. In the screen 10, the refractive index of each layer is set so that light passes through the second layer 12, the third layer 13, and the fourth layer 14 without being refracted. Therefore, as described above, n2 = n4. Then, when the refractive index of the portion of the third layer 13 excluding the flakes 40 is n3, the material for forming the third layer 13 is selected so that n2 = n3 = n4.

[0056] For example, if the third layer 13 contains a binder resin, the refractive index of the binder resin is set to n3, and a binder resin is selected such that n3 is equal to n2 and n4. Alternatively, if the third layer 13 does not contain a binder resin, the refractive index of the bleed component dissolved from the second layer 12 is n3. Therefore, the resin and solvent constituting the second layer 12 are selected so that the refractive index of the bleed component is equal to n2 and n4.

[0057] Note that n2, n3, and n4 do not have to be perfectly equal, as long as they are approximately equal, for example, as long as the difference in refractive index between adjacent layers is within 0.05.

[0058] (5th layer: 2nd base layer) The fifth layer 15 is a second substrate layer made of a light-transmitting substrate. The fifth layer 15 is a protective substrate that protects the fourth layer 14. Like the first layer 11, the fifth layer 15 is made of, for example, a transparent resin such as PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), MS (methyl methacrylate-styrene), or PP (polypropylene).

[0059] The fifth layer 15 can be formed by adhering a base film made of the above material to the surface of the fourth layer 14. For example, when forming the fourth layer 14 using a UV-curable adhesive, the fourth layer 14 and the fifth layer 15 can be formed by filling and curing the UV-curable adhesive between the base film made of the above material and the Fresnel lens layer (second layer 12) on whose surface the third layer 13 has been formed. The fifth layer does not necessarily have to be provided.

[0060] FIG. 6 is a graph showing the relationship between the brightness of the output light L1 emitted from the screen 10 and the output angle. The horizontal axis represents the angle when the screen 10 is tilted in the arrangement direction of the unit convex shapes 30 (the vertical direction in FIG. 2) with respect to the normal direction (Z direction) of the screen 10. A screen 10 according to the present invention was manufactured and the brightness of the output light L1 was measured. As a result, the maximum brightness B was 1350 cd / m2. Furthermore, the angle range (half-brightness angle θ) in which the brightness of the output light L1 is half of the maximum brightness B was 10°≦θ≦14°. The half-brightness angle θ represents the viewing angle of the screen 10.

[0061] Fig. 7 is a scanning electron microscope (SEM) photograph of the third layer 13 (reflective layer) taken in plan view. Fig. 8 is a scanning electron microscope (SEM) photograph showing the cross-sectional structure of the screen 10. As shown in Figs. 7 and 8, the third layer 13 formed in the manufacturing direction of this embodiment is a semi-transparent reflective layer in which thin pieces 40 (aluminum vapor-deposited flakes) are appropriately dispersed.

[0062] (Action and effect) As described above, the screen 10 of this embodiment uses a coating layer containing flakes 40 that reflect the image light L as a reflective layer (third layer 13). The coating layer can be formed by wet coating technology, so it can be manufactured stably regardless of the production volume or size of the screen 10, and mass production and large-scale production are also easy. In addition, the Fresnel lens layer (second layer 12) on which the reflective layer is formed is also formed. The surface of the unit convex shape 30 of each of the first and second layers 12 and 13 is rough in the area where the reflective layer is formed. Therefore, the reflective layer can increase scattered light by utilizing the disturbance in the orientation of the flakes 40 caused by the unevenness of the rough surface, thereby achieving high brightness and a wide viewing angle for the screen 10. In addition, because the interfaces between the Fresnel lens layer (second layer 12), the reflective layer (third layer 13), and the optically transparent layer (fourth layer 14) are rough, peeling at the interfaces is less likely to occur, resulting in high durability.

[0063] Furthermore, in this embodiment, the method for forming the reflective layer (third layer 13) involves eroding the surface of the Fresnel lens layer (second layer 12) using the attacking force of the solvent contained in the coating material 41, thereby simultaneously forming a roughened surface when forming the reflective layer (third layer 13) (coating layer). This makes it possible to avoid increased mold costs and complicated manufacturing processes for the screen 10, which would be required to form the roughened surface necessary for diffuse reflection. Furthermore, by selecting and compounding the solvent, it is possible to appropriately erode the surface of the Fresnel lens layer (second layer 12) and form a roughened surface with a desired roughness. This makes it easy to adjust the roughness of the roughened surface, a parameter that affects the viewing angle.

[0064] By including the reflective layer (third layer 13) of the above configuration, the screen 10 of this embodiment was confirmed to have a half-brightness angle θ, which is the angle change from the emission angle at which the brightness of the emitted light L1 is at its maximum to the emission angle at which the brightness of the emitted light L1 is half of the maximum, of 10°≦θ≦14°. It was also confirmed that the maximum brightness B was 1350 cd / m2. Therefore, high brightness and a wide viewing angle were achieved.

[0065] In the manufacturing method of the screen 10 of this embodiment, the coating material 41 has a solvent content of 10 to 10 parts by weight of the flakes 40. When this content ratio is set, the surface of the Fresnel lens layer (second layer 12) is appropriately roughened, thereby generating an appropriate amount of scattered light. As a result, the high brightness and wide viewing angle described above can be achieved.

[0066] The reflective layer (third layer 13) in this embodiment is a semi-transmissive reflective layer, so that light from the rear side Z2 of the screen 10 passes through the screen 10, and the screen 10 can be used as a transmissive screen.

[0067] In the screen 10 of this embodiment, the difference in refractive index between adjacent layers of the Fresnel lens layer (second layer 12), reflective layer (third layer 13), and optically transparent layer (fourth layer 14) is zero. Therefore, light passes through the boundaries between these layers without being refracted, making it possible to form a transparent screen 10 that allows the back side to be seen through. Note that the refractive indices of these three layers do not need to be the same, as long as the difference in refractive index between adjacent layers is small.

[0068] In the manufacturing method of screen 10 of this embodiment, in the step of forming the Fresnel lens layer (second layer 12), UV-curable resin material 36 is supplied to mold surface 34 on which inverted shapes of unit convex shapes 30 are arranged, and resin material 36 is cured by irradiating it with UV light while being pressed through first base layer (base film 35) that transmits UV light, and then released from mold surface 34. In this way, when the Fresnel lens layer (second layer 12) is formed by 2P molding, it is possible to suppress crosslinking inhibition by oxygen in the UV curing process and to reinforce the toughness of the Fresnel lens layer. [Explanation of symbols]

[0069] 1...image display device, 2...observer, 10...screen, 11...first layer, 12...second layer, 13...third layer, 14...fourth layer, 15...fifth layer, 20...image source, 30...unit convex shape, 31...first surface, 32...second surface, 33...laminated body, 34...mold surface, 35...substrate film, 36...resin material, 40...thin piece, 41...coating material, ap...tilt angle of first surface, C...transparent area, L...image light, L1...emitted light, L2...light from the rear side, Z1...image source side, Z2...rear side

Claims

1. A screen onto which image light is incident, a light-transmitting first substrate layer; a Fresnel lens layer laminated on the first base material layer, in which unit convex shapes that are convex on an opposite side to the first base material layer are arranged; a reflective layer formed on the surface of the unit convex shape and including a coating layer containing flakes that reflect the image light; an optically transparent layer laminated on the reflective layer from the side opposite to the first base layer and filling in the irregularities of the unit convex shapes; the surface of the unit convex shape is roughened in a region where the reflective layer is to be formed, The reflective layer is characterized in that some of the flakes are arranged in a disordered orientation along the irregularities of the rough surface, thereby diffusing and reflecting some of the image light.

2. 2. The screen according to claim 1, wherein the reflective layer is a semi-transmissive reflective layer that transmits a part of incident light.

3. 2. The screen according to claim 1, wherein the Fresnel lens layer, the reflective layer, and the optically transparent layer have a refractive index difference of 0.05 or less between adjacent layers.

4. 2. The screen according to claim 1, wherein the reflective layer contains bleeding components dissolved from the resin forming the Fresnel lens layer.

5. 5. The screen according to claim 4, wherein the reflective layer contains a binder resin, and the flakes are dispersed in the binder resin.

6. 5. The screen according to claim 4, wherein the reflective layer does not contain a binder resin, and the flakes are attached to the rough surface via the bleeding component.

7. A screen as described in claim 1, characterized in that the half-brightness angle θ, which is the angular change from the exit angle at which the brightness of the exit light reflected by the reflective layer is at its maximum value to the exit angle at which the brightness of the exit light is 1 / 2 of the maximum value, is 10°≦θ≦14°.

8. 2. The screen according to claim 1, wherein the thin pieces are aluminum vapor-deposited flakes.

9. 2. The screen according to claim 1, further comprising a light-transmitting second base material layer laminated on the optically transparent layer from the side opposite to the Fresnel lens layer.

10. A method for manufacturing a screen including a Fresnel lens layer in which unit convex shapes onto which image light is incident are arranged, and a reflective layer formed on a surface of the unit convex shapes, comprising: a coating material containing a volatile solvent and flakes that reflect the image light is applied to the surface of the unit convex shape; A method for manufacturing a screen, characterized in that the solvent erodes the surface of the unit convex shape, transforming it into a rough surface, and arranging some of the flakes in a disordered orientation along the unevenness of the rough surface, thereby forming the reflective layer, until the solvent evaporates.

11. The method for manufacturing a screen according to claim 10, wherein the coating material has a ratio of the content of the solvent to the content of the flakes of 1:10 or more.

12. The method for manufacturing a screen according to claim 10, wherein the coating material contains a binder resin.

13. The coating material does not contain a binder resin, The method for manufacturing a screen according to claim 10, wherein the flakes are attached to the rough surface via a bleeding component dissolved from a resin that forms the unit convex shapes.

14. 11. The method for manufacturing a screen according to claim 10, wherein in the step of forming the Fresnel lens layer, a UV-curable resin material is supplied to a mold surface on which inverted shapes of the unit convex shapes are arranged, and the resin material is hardened by exposing it to UV light while being pressurized via a base film that transmits UV light, and then released from the mold surface.

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