Screen and manufacturing method thereof

Abstract

To avoid increasing mold costs and complicating the screen manufacturing process in order to increase the brightness of the screen and ensure the viewing angle. [Solution] The screen 10 comprises, in order from the image source side Z1, a first base material layer (first layer 11), a Fresnel lens layer (second layer 12), a reflective layer (third layer 13), an optically transparent layer (fourth layer 14), and a second base material layer (fifth layer 15). The Fresnel lens layer comprises an array of unit convex shapes 30 that are convex on the back side Z2. The surface of the unit convex shapes 30 is rough, and a reflective layer is formed on the rough surface. The reflective layer is a coating layer in which flakes 40 that reflect image light are dispersed. In the reflective layer, at least some of the flakes 40 are arranged in a state in which their orientation is disturbed along the unevenness of the rough surface, and they diffusely reflect some of the image light. When forming the reflective layer, the surface of the unit convex shapes 30 is eroded and roughened by a solvent contained in the coating material, so that the orientation of the flakes 40 is moderately disturbed.

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 that transmits light from the rear side of 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. In addition, brightness can be ensured by transmitting daylight 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 the view and daylight from the glass can be unobstructed when not in use.

[0003] Patent Document 1 describes this type of screen. The screen of 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. The first optically transparent layer has unit optical shapes with triangular cross sections that constitute a Fresnel lens arranged on the surface opposite to the image source (rear side). The 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 mold having a fine uneven shape formed on its surface is used as a molding die used when forming the first optical transparent layer. As a result, a fine uneven shape is formed on the surface of the unit optical shape having a triangular cross section. The reflective layer is formed on the surface of the unit optical shape by deposition, and is therefore a layer having a fine uneven shape. As a result, the reflective layer diffusely reflects a part of the image light, and the emission angle range of the image light from the screen is expanded. Therefore, the angle range in which a bright image can be viewed is expanded, and the viewing angle is expanded. [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, in order to form a reflective layer with a fine uneven shape necessary for diffuse reflection, plating and etching are 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. In addition, when it becomes necessary to adjust the fine uneven shape, which is a parameter that affects the scattering degree in diffuse reflection, the mold needs to be changed, so adjusting the scattering degree 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 fine uneven 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 separately performed on the Fresnel lens after demolding. This increases the number of steps, requires additional processing equipment, and complicates the screen manufacturing process.

[0008] In addition, in Patent Document 1, a reflective layer is formed by evaporating a reflective material onto the surface of a Fresnel lens, but with this method of forming a reflective layer, it is difficult to efficiently carry out mass production, production of large screens, or custom-made production of 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 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 is roughened 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] Moreover, one aspect of a 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 into 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 evaporates, some of the flakes are arranged in a disordered orientation along the unevenness of the rough surface to form 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 by wet coating technology, so it can be manufactured stably regardless of the production volume and size of the screen, and it is easy to mass-produce and enlarge it. In addition, the scattering light is increased by utilizing the disturbance of the flake orientation due to the unevenness of the rough surface, so that the screen can achieve high brightness and a wide viewing angle. Furthermore, since the interface between the Fresnel lens layer, the reflective layer, and the optically transparent layer is a rough surface, peeling at the interface is unlikely to occur, and the durability is high.

[0013] In addition, in the screen and manufacturing method thereof according to 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 at the same time as forming the reflective layer (coating layer). Therefore, it is possible to avoid an increase in mold costs and a complication of the screen manufacturing process. In addition, by selecting and blending the solvent, the surface of the Fresnel lens layer can be appropriately eroded to form a rough surface with a desired roughness. Therefore, the roughness of the rough surface, which is a parameter that affects the viewing angle, can be easily adjusted.

[0014] In the screen of the above embodiment, the reflective layer is preferably a semi-transmissive reflective layer that transmits a part of the incident light. In this way, the light from the rear side of the screen transmits through the screen, so that the screen can be used as a transmissive screen. In addition, the transmittance can be adjusted by selecting and mixing the flakes.

[0015] In the screen of the above embodiment, the Fresnel lens layer, the reflective layer, and the optically transparent layer preferably have a refractive index difference of 0.05 or less between adjacent layers. In this way, light from the rear side of the screen passes 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 embodiment, the reflective layer contains a bleeding component dissolved from the resin forming the Fresnel lens layer. The mixing of the bleeding component into the reflective layer means that the solvent contained in the coating material has an attacking force that corrodes the resin, and the surface of the Fresnel lens layer is corroded by the solvent to form a rough surface. By utilizing the attacking force of the solvent, it is possible to form a rough surface at the same time as forming the coating layer, without separately carrying out a roughening step on the mold or the Fresnel lens layer.

[0017] In the screen of the above embodiment, the reflective layer may contain a binder resin, and the flakes may be dispersed in the binder resin. In the method for manufacturing the screen of the above embodiment, the coating material may contain a binder resin. In this case, the characteristics of the reflective layer can be adjusted by selecting the binder resin. For example, by selecting a binder resin so as to eliminate the difference in refractive index between the Fresnel lens layer and the optically transparent layer, the incident light can be passed through 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. In the manufacturing method of the screen of the above embodiment, the coating material does not contain a binder resin, and the flakes can be attached to the rough surface via the bleeding component dissolved from the resin forming the unit convex shape. In this way, when the coating material does not contain a binder resin, the flakes are attached to the rough surface by the adhesive force of the bleeding component dissolved by the attack force of the solvent. Therefore, the flakes are arranged in a disordered orientation along the unevenness, and the scattered light can be increased.

[0019] In the screen of the above embodiment, the half-brightness angle θ, which is the amount of change in angle 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 half of the maximum value, is 10°≦θ≦14°. Since the half-brightness angle θ means the viewing angle, the screen of this embodiment can realize a wide viewing angle.

[0020] In the screen of the above aspect, the thin pieces are preferably aluminum vapor deposition flakes. Aluminum has a high reflectance and can increase scattered light. Therefore, even though it is a transmission type 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 the optically transparent layer has a second base material layer laminated on 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 content of the solvent to the content of the flakes of 10 or more. With such a content ratio, the surface of the Fresnel lens layer can be eroded and appropriately roughened. Therefore, a wide viewing angle can be realized.

[0023] In the screen manufacturing method of 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 through a substrate film that transmits UV light, thereby curing 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 crosslinking inhibition due to oxygen in the UV curing process, and to reinforce toughness. Effect 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. In addition, peeling is unlikely to occur at the interfaces between the Fresnel lens layer, the reflective layer, and the optically transparent layer, making it highly durable. Furthermore, because the reflective layer is a coating layer, it can be manufactured stably regardless of the production volume or size of the screen, and mass production and large-scale production are also easy. [Brief description of the drawings]

[0025] [Figure 1] 1A to 1C are explanatory diagrams showing a usage state of a screen according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the screen shown in FIG. [Diagram 3]FIG. 4 is an explanatory diagram of a manufacturing process for the second layer (Fresnel lens layer). [Figure 4] 3 is a cross-sectional view of a third layer (reflective layer) and a partially enlarged view thereof. FIG. [Diagram 5] FIG. 4 is an explanatory diagram of a manufacturing process for the third layer (reflective layer). [Figure 6] 1 is a graph showing the relationship between the luminance and the exit angle of light emitted from a screen. [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 a cross-sectional structure of a screen. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0027] (Image display device) Fig. 1 is an explanatory diagram that shows a schematic diagram of 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 a normal direction of the screen 10. In the following description, the side of the screen 10 where the image light L is incident, in other words, the side of the screen 10 where the image source 20 is arranged, is referred to as an image source side Z1. The side of the screen 10 opposite to the image source side Z1 is referred to as a back side Z2.

[0028] As shown in FIG. 1, the screen 10 reflects and emits the 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 superimposed on an object or 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 laminated 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] (2nd 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, each unit convex shape 30 has an arc-shaped planar shape when viewed from the Z direction. The plurality of unit convex shapes 30 are concentrically arranged around one point when viewed from the Z direction.

[0034] As shown in FIG. 2, each of the multiple unit convex shapes 30 has a first surface 31 inclined with respect to the normal direction (Z direction) of the screen 10, and a second surface 32 inclined with respect to the first surface 31. In the example shown in FIG. 2, the first surface 31 has an inclination angle with respect to the Z direction that 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-angled 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, in the second layer 12, the cross-sectional shape of the multiple unit convex shapes 30 becomes larger as it goes away from the image source 20, and the height of the unit convex shapes 30 in the Z direction becomes larger as it goes away from the image source 20. As described above, the multiple unit convex shapes 30 are arc-shaped with one point as the center, and the cross-sectional shape of the unit convex shapes 30 becomes larger and the arrangement pitch becomes larger as it goes away from the center of the arc. The appropriate arrangement pitch of the unit convex shapes 30 is 20 μm to 250 μm. In addition, 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 a direction from the exit position toward the observer 2.

[0036] The cross-sectional shape and arrangement pitch of the unit convex shapes 30 are not limited to the above shapes. 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. The cross-sectional shapes of the unit convex shapes 30 may be the same, and the arrangement pitch may be constant. The planar shape of the unit convex shapes 30 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 a manufacturing process of the second layer 12 (Fresnel lens layer). As 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, in the 2P molding, a molding die having a die surface 34 on which the inverted shape of the unit convex shape 30 is formed, and a base film 35 made of a resin that constitutes the first layer 11 are used.

[0038] First, as shown in the left diagram of FIG. 3, an 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 pressurized 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 the substrate film 35, which transmits UV light, to expose and cure the resin material 36. A Fresnel lens layer is formed by curing the resin material 36, and the resin material 36 is bonded to the substrate 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 being released 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 using a resin other than the UV-curable resin, another curing process may be performed in place of the process of exposing to UV light in the pressure curing process 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 the image light L. As shown in FIG. 2, the image light L that is 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. In addition, as 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 is emitted from 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] It should be noted that 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 on the entire surface of each unit convex shape 30. For example, in the case of a screen 10 used in a mode in which the image light L is incident on the first surface 31 of each unit convex shape 30 and the image light L is not incident on the second surface 32 as shown in Fig. 2, it is sufficient that the third layer 13 is 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 FIG. 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 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 in the same direction, 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, but at this time, since it is reflected by the flakes 40 with a disordered orientation, the emitted light L1 contains a moderate amount of scattered light.

[0045] As shown in the partially enlarged view of FIG. 4, the third layer 13 has regions where a plurality of flakes 40 overlap, but the flakes 40 are arranged sporadically in a planar view. Thus, the third layer 13 has transparent regions C where no flakes 40 are arranged. This allows the third layer 13 to transmit a portion of the incident light and reflect a portion of it. Also, light from the rear side Z2 of the screen 10 transmits through the screen 10. Note that FIG. 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 FIG. good.

[0046] The flakes 40 are aluminum vapor deposition flakes. For example, fine aluminum flakes used as pigments in metallic paints can be used as the flakes 40. The aluminum flakes preferably have 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 deposition 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, since the third layer 13 is a coating layer, 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 the coating material 41 is applied, 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 deposition 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. In this way, an appropriate amount of coating material 41 is evenly applied to the surface of the unit convex shape 30.

[0049] The coating material 41 includes at least a volatile solvent and flakes 40, but may also include other components. For example, it may include 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 include other additives (auxiliaries). For example, it may include additives for adjusting viscosity and other properties.

[0050] After the coating material 41 is applied, the resin constituting the unit convex shapes 30 is corroded by the attacking force of the solvent until the solvent in the coating material 41 evaporates and disappears, and the surface of the unit convex shapes 30 is roughened (see the lower diagram in FIG. 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 FIG. 5, the third layer 13 is thinned by the evaporation and disappearance of the solvent. When the coating material 41 contains a binder resin, the binder resin does not disappear, so that the third layer 13 has flakes 40 dispersed in the layer containing the binder resin, as shown in the lower diagram of FIG. 5. Note that, like FIG. 4, FIG. 5 shows the flakes 40 dispersed in the third layer 13 and the rough surface formed by erosion of the solvent, and the shape of the actual rough surface, the shape, size, and degree of dispersion of the flakes 40 may be different from those shown in FIG. 5.

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

[0053] The coating material 41 is used with the solvent content adjusted to 10 parts by weight per part by weight of the flakes 40. This allows the attacking power of the solvent to be exerted, and the surface of the unit convex shape 30 is eroded and appropriately roughened.

[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 having the third layer 13 formed on the surface. The fourth layer 14 is made of an optically transparent resin, an OCR (Optically Clear Resin) resin, or the like. For example, the fourth layer 14 can be formed by applying a transparent UV-curable adhesive and then curing it.

[0055] The resin constituting the fourth layer 14 has a refractive index n4 equal to the refractive index n2 of the resin constituting the second layer 12. In the screen 10, the refractive indexes of the second layer 12, the third layer 13, and the fourth layer 14 are set so that light passes through them without being refracted. For this reason, 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 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 completely equal, but may be approximately equal, for example, so long as the difference in refractive index between adjacent layers is within 0.05.

[0058] (5th layer: 2nd base material layer) The fifth layer 15 is a second base material layer made of a light-transmitting base material. The fifth layer 15 is a protective base material that protects the fourth layer 14. For example, like the first layer 11, the fifth layer 15 is made of 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 with 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 is formed. The fifth layer does not have to be provided.

[0060] 6 is a graph showing the relationship between the luminance and the emission angle of the outgoing light L1 emitted from the screen 10. The horizontal axis is the angle when the angle is inclined 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. The screen 10 according to the present invention was manufactured and the luminance of the outgoing light L1 was measured, and the maximum luminance B was 1350 cd / m2. The angle range (half-luminance angle θ) in which the luminance of the outgoing light L1 is 1 / 2 of the maximum luminance B was 10°≦θ≦14°. The half-luminance 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, it can be seen that the third layer 13 formed in the manufacturing direction of this embodiment is a semi-transmissive reflective layer in which thin pieces 40 (aluminum vapor deposition flakes) are appropriately dispersed and arranged.

[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 and size of the screen 10, and it is easy to mass-produce and enlarge the screen. In addition, the Fresnel lens layer (second layer 12) on which the reflective layer is formed ) has a rough surface 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 realizing high brightness and ensuring 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 surfaces, peeling at the interfaces is unlikely to occur, and the screen has high durability.

[0063] Furthermore, in this embodiment, as a method for forming the reflective layer (third layer 13), the surface of the Fresnel lens layer (second layer 12) is eroded by the attacking force of the solvent contained in the coating material 41, and a rough surface can be formed at the same time as forming the reflective layer (third layer 13) (coating layer). Therefore, it is possible to avoid an increase in mold costs and a complication of the manufacturing process of the screen 10 for forming a rough surface necessary for diffuse reflection. In addition, by selecting and blending the solvent, it is possible to appropriately erode the surface of the Fresnel lens layer (second layer 12) to form a rough surface with a desired roughness. Therefore, the roughness of the rough surface, which is a parameter that affects the viewing angle, can be easily adjusted.

[0064] It was confirmed that the screen 10 of this embodiment, which includes the reflective layer (third layer 13) having the above-mentioned configuration, has 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 value to the emission angle at which the brightness of the emitted light L1 is 1 / 2 of the maximum value, of 10°≦θ≦14°. It was also confirmed that the maximum brightness B is 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 or more relative to the content of the flakes 40 of 1. When the content ratio is set to such a value, the surface of the Fresnel lens layer (second layer 12) is appropriately roughened, so that an appropriate amount of scattered light is generated. As a result, the high brightness and wide viewing angle as described above can be realized.

[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 refractive index difference 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, so it is possible to form a transparent screen 10 through which the back side can be seen through. The refractive indices of these three layers do not need to be the same, as long as the refractive index difference between adjacent layers is small.

[0068] In the manufacturing method of the screen 10 of this embodiment, in the step of forming the Fresnel lens layer (second layer 12), a UV-curable resin material 36 is supplied to a mold surface 34 on which the inverted shapes of the unit convex shapes 30 are arranged, and the resin material 36 is cured by irradiating it with UV light while being pressurized through a first base material layer (base material film 35) through which UV light transmits, and then released from the mold surface 34. In this way, when the Fresnel lens layer (second layer 12) is formed by 2P molding, crosslinking inhibition due to oxygen in the UV curing process can be suppressed, and the toughness of the Fresnel lens layer can be reinforced. [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...laminate, 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 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 a surface of the unit convex shape and including a coating layer containing flakes that reflect the image light; an optically transparent layer that is laminated on the reflective layer from the side opposite to the first base layer and fills in the irregularities of the unit convex shapes; a surface of the unit convex shape is roughened in a region where the reflective layer is to be formed; the reflective layer is arranged such that a portion of the flakes is arranged in a state where its orientation is disordered along the unevenness of the rough surface, and diffusely reflects a portion of the image light; The screen is characterized in that the reflective layer contains a bleeding component dissolved from a resin forming the Fresnel lens layer.

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 a binder resin, and the flakes are dispersed in the binder resin.

5. 2. The screen according to claim 1, wherein the reflective layer does not contain a binder resin, and the flakes are attached to the rough surface via the bleeding component.

6. The screen 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°.

7. 2. The screen according to claim 1, wherein the thin pieces are aluminum vapor deposition flakes.

8. 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.

9. 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 a surface of the unit convex shape; A method for manufacturing a screen, characterized in that, while the solvent evaporates, the surface of the unit convex shape is eroded by the solvent to transform it into a rough surface, and part of the flakes are arranged in a disordered orientation along the unevenness of the rough surface to form the reflective layer.

10. The method for manufacturing a screen according to claim 9, characterized in that the coating material has a content of the solvent per content of the flakes of 10 or more.

11. The method for manufacturing a screen according to claim 9 , wherein the coating material contains a binder resin.

12. The coating material does not contain a binder resin, The method for manufacturing a screen according to claim 9, wherein the flakes are attached to the rough surface via a bleeding component dissolved from a resin that forms the unit convex shapes.

13. 10. The method for manufacturing a screen according to claim 9, wherein in the step of forming the Fresnel lens layer, a UV-curable resin material is supplied to a mold surface on which the 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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