Reflective screens, video display devices

Abstract

To provide a reflection type screen that can reduce glare of a video and display a clear video, and a video display device including the same.SOLUTION: A screen 10 is a reflection type screen, and comprises: a first optical shape layer 12 in which a plurality of unit optical shapes 121 convex on the back side are arranged; a reflection layer 13 that is formed in part of at least first inclined surfaces 121a of the unit optical shapes 121, has a fine and irregular rugged shape formed on its surface, and diffuses and reflects at least part of light incident thereon; and a light control layer 16 that is located closer to a video source than the reflection layer 13 in a thickness direction of the screen 10, diffuses and transmits light incident from a specific angular range, and transmits light incident from the outside of the specific angular range without diffusing the light. The specific angular range is a range of 25° or more and 55° or less on a side where the video source LS is located with respect to a straight line perpendicular to a surface of the light control layer 16 facing the video source.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a reflective screen and a video display device including the same.

Background Art

[0002] Conventionally, various reflective screens have been developed that reflect and display video light projected from a video source. Among them, for example, a reflective screen having transparency (see, for example, Patent Document 1) can be fixed by being attached to a highly translucent member such as window glass, etc., reflect the projected video light to display a video, and when not in use, etc., when the video light is not projected, the scenery on the other side of the screen can be observed through the screen, so the demand is increasing due to high design quality, etc.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As shown in Patent Document 1, when the reflecting surface (the surface of the reflective layer) has a rough surface with a fine uneven shape, the video light is diffusely reflected by the reflecting surface, so it is not necessary to provide a light diffusing layer containing light diffusing particles or the like on the video source side of the reflective layer, and the transparency of the reflective screen can be increased. However, when such a rough reflecting surface is provided, there is a problem that flickering of the video (also called speckle) is likely to occur.

[0005] Such flickering of the video hinders comfortable visual recognition of the video and is not preferable. Further, such flickering of the video tends to be particularly visible when using a video source using a laser light source that can display a bright and clear video. To reduce this kind of glare in images, it is effective to incorporate a light-diffusing layer containing the aforementioned diffusing material. However, such light-diffusing layers have the problem of causing image blurring (reduced resolution) and reducing the transparency of the screen.

[0006] The object of the present invention is to provide a reflective screen that can reduce glare in images and display clear images, and an image display device equipped with the same. [Means for solving the problem]

[0007] The present invention solves the above-mentioned problems by the following means. For the sake of ease of understanding, the embodiments of the present invention will be described using reference numerals corresponding to those numerals, but the invention is not limited thereto. The first invention is a reflective screen that displays an image by reflecting at least a portion of the image light projected from an image source, comprising: a first optical shape layer (12) having a first surface (121a) into which the image light is incident and a second surface (121b) intersecting thereto, and having a plurality of unit optical shapes (121) arranged on the back side that are convex; a reflective layer (13) formed on at least a portion of the first surface of the unit optical shapes, having fine and irregular uneven shapes formed on its surface, which diffusely reflects at least a portion of the incident light; and a reflective layer located on the image source side of the reflective layer in the thickness direction of the reflective screen, which diffuses and transmits light incident from a specific angular range (R1), and the specific angular range A reflective screen (10,20) is characterized by comprising: an optical control layer (16) that transmits light incident from outside the bounding box (R2) without diffusion, and not comprising an optical diffusion layer containing light-diffusing particles, wherein the angle α that the first surface of the unit optical shape makes with a surface parallel to the screen surface increases in one direction along the arrangement direction of the unit optical shape, and the specific angular range is a range in which, in a cross section passing through the center point of the reflective screen and parallel to the arrangement direction of the unit optical shape and the thickness direction of the reflective screen, the angle α is 25° or more and 55° or less on the side of the smaller angle α with respect to a straight line perpendicular to the surface of the optical control layer that is on the image source side. The second invention is a reflective screen (10,20) of the first invention, characterized in that, in the thickness direction of the reflective screen, the distance between the image source side surface of the first optical shape layer (12) and the back side surface of the light control layer (16) is 0.5 mm or less. The third invention is a reflective screen (10,20) of the first or second invention, characterized in that the reflective layer (13) is semi-transparent, reflecting a portion of the incident light and transmitting a portion of it, and has a second optical shape layer (14) provided adjacent to the reflective layer on the back side of the reflective layer, which has light transmittance and is laminated to fill the valleys formed by adjacent unit optical shapes (121), the back surface of the second optical shape layer being planar, and having a refractive index equal to or small enough to be considered equal to that of the first optical shape layer (12). The fourth invention is a reflective screen (10,20) characterized in that, in any of the first to third inventions, the first optical shape layer (12) has a Fresnel lens shape on its back side, the unit optical shape (121) is arc-shaped when viewed from a direction perpendicular to the screen surface, and is arranged concentrically around a point located outside the display area of ​​the reflective screen. The fifth invention is a reflective screen (20) that, in any of the first to fourth inventions, is equipped with a light-absorbing layer (30) that absorbs a portion of the incident light and transmits a portion of it. The sixth invention is a reflective screen (20) of the fifth invention, characterized in that the light-absorbing layer (30) is provided on the back side of the reflective layer (13). The seventh invention is a reflective screen (20) of the sixth invention, characterized in that the light absorbing layer (30) is a dimming layer that can select between a state in which the absorption rate for light at a large angle of incidence is greater than the absorption rate for light at an angle of incidence of 0°, and a state in which the difference in light absorption rate depending on the angle of incidence is small. The eighth invention is a reflective screen (20) characterized in that, in any of the fifth to seventh inventions, the reflective layer (13) is semi-transparent, reflecting a portion of the incident light and transmitting a portion of it; a second optical shape layer (14) is provided adjacent to the reflective layer on the back side of the reflective layer, has light transmittance, and is laminated to fill the valleys formed by adjacent unit optical shapes; and in the thickness direction of the reflective screen, the distance (D2) from the image source side surface of the light absorption layer (30) to the back side surface of the second optical shape layer (14) is greater than the distance (D1) from the back side surface of the light control layer (16) to the image source side surface of the first optical shape layer (12). The ninth invention is an image display device (1) comprising a reflective screen (10, 20) from any of the first to eighth inventions, and an image source (LS) that projects image light onto the reflective screen. The tenth invention is an image display device (1) of the ninth invention, characterized in that the specific angular range (R1) of the reflective screen (10,20) includes the main incident angular range of the image light projected by the image source (LS). [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a reflective screen that can reduce glare in images and display clear images, and an image display device equipped with the same. [Brief explanation of the drawing]

[0009] [Figure 1] This is a diagram showing the video display device 1 of the first embodiment. [Figure 2] This figure shows the layer configuration of the screen 10 in the first embodiment. [Figure 3] This is a diagram illustrating the first optical shape layer 12. [Figure 4] This diagram illustrates the optical control function of the optical control layer 16. [Figure 5] This figure shows an example of image light and ambient light incident on the screen 10 of the first embodiment. [Figure 6] This is a diagram showing each screen during measurement of peak brightness etc. and during visual evaluation, as well as the positions of the video source LS, luminance meter K, observer O3, etc. [Figure 7] This is a diagram showing the layer structure of the screen 20 of the second embodiment. [Figure 8] This is a diagram showing the state of alignment of the liquid crystal material in the dimming layer 30. [Figure 9] This is a diagram showing the layer structure of the screen 50 of the modified form.

Embodiments for Carrying out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. Note that each of the figures shown below, including FIG. 1, is a schematically shown figure, and the size and shape of each part are exaggerated as appropriate for easy understanding. In this specification, with respect to terms specifying shapes and geometric conditions, such as terms like parallel and orthogonal, in addition to having a strict meaning, a state having an error such that it exhibits a similar optical function and can be regarded as parallel or orthogonal is also included.

[0011] Also, in this specification, words such as plate, sheet, film, etc. are used, but in general usage, in order of decreasing thickness, they are used in the order of plate, sheet, film, and this is also followed in this specification. However, since there is no technical meaning in such a distinction, these words can be replaced as appropriate. Furthermore, the numerical values such as the dimensions of each member described in this specification and the material names, etc. are examples as embodiments, and are not limited thereto, and can be selected as appropriate.

[0012] (First Embodiment) FIG. 1 is a diagram showing the video display device 1 of the first embodiment. FIG. 1(a) is a perspective view of the video display device 1, and FIG. 1(b) is a view of the video display device 1 as seen from the side (the +X side described later). The image display device 1 includes a screen 10, an image source LS, etc. The screen 10 is a reflective screen that reflects a part of the image light L0 projected from the image source LS and displays an image on the screen. Details of this screen 10 will be described later.

[0013] Here, for ease of understanding, in each of the figures shown below including FIG. 1, an XYZ orthogonal coordinate system is provided as appropriate. In this coordinate system, the horizontal direction (left - right direction) of the screen of the screen 10 is the X - direction, the vertical direction (up - down direction) is the Y - direction, and the thickness direction of the screen 10 is the Z - direction. The screen of the screen 10 is parallel to the XY plane, and the thickness direction (Z - direction) of the screen 10 is orthogonal to the screen of the screen 10. Also, when viewed from an observer O1 located in the front direction on the image source side of the screen 10, the direction toward the right side in the horizontal direction is the +X direction, the direction toward the upper side in the vertical direction is the +Y direction, and the direction from the back side (rear side) to the image source side in the thickness direction is the +Z direction. Furthermore, in the following description, unless otherwise specified, the up - down direction of the screen, the left - right direction of the screen, and the thickness direction refer to the up - down direction (vertical direction), the left - right direction (horizontal direction), and the thickness direction (depth direction) of the screen 10 in the usage state of this screen 10, and are parallel to the Y - direction, X - direction, and Z - direction, respectively.

[0014] The image source LS is an image projection device that projects the image light L0 onto the screen 10. For example, it is a short - focus projector. In this embodiment, the image source LS uses a DLP - type projector that uses a high - pressure mercury lamp as a light source. However, it is not limited to this, and depending on the desired optical performance, the usage environment of the image display device 1, etc., an image source using other light sources such as lasers or LEDs may be used. In the usage state of this image display device 1, when the screen (display area) of the screen 10 is viewed from the front direction (the normal direction of the screen surface), it is at the center in the left - right direction of the screen of the screen 10 and is located below the screen of the screen 10 in the vertical direction. In this specification, the screen surface refers to the plane of the screen when viewed as a whole. The screen surface of screen 10 is parallel to the screen plane (XY plane) of screen 10.

[0015] The image source LS can project the image light L0 at an angle from a position significantly closer to the surface of the screen 10 in the depth direction (Z direction) compared to conventional general-purpose projectors where the projected image light L0 is positioned directly in front of the screen. Therefore, compared to conventional general-purpose projectors, the image source LS has a shorter projection distance to the screen 10, a larger incident angle at which the projected image light L0 enters the screen 10, and a larger change in the incident angle (change from minimum to maximum value).

[0016] Screen 10 is a semi-transparent reflective screen that displays an image to observer O1 by reflecting a portion of the image light L0 projected by the image source LS toward the observer O1, who is located in front of the image source (+Z side). Screen 10 is transparent, and observer O1 can observe the scenery on the other side (-Z side) through the screen 10. The screen (display area) of screen 10, when in use, is roughly rectangular in shape, with the longer side running horizontally from the perspective of observer O1. Furthermore, screen 10 has a diagonal size of approximately 40 to 100 inches and an aspect ratio of 16:9. Furthermore, the screen 10 may have other shapes as viewed from the observer O1's side, or its screen size may be 40 inches or less. Its size and shape can be appropriately selected according to the purpose of use and the environment in which it is used.

[0017] In this embodiment, the screen 10 is integrally bonded (or partially fixed) to a support plate (not shown) via a bonding layer (not shown) on the back side, thereby maintaining the flatness of the screen. The support plate is a highly rigid, flat member, and can be made of a resin such as acrylic resin or PC (polycarbonate) resin, or a plate-shaped member such as glass. Furthermore, as in this embodiment, if the screen 10 is transparent, it is preferable that the support plate is also transparent. However, the screen 10 may also be supported on all four sides by a frame member or the like (not shown) to maintain its flatness. The video display device 1 of this embodiment can be applied to indoor partitions, video displays at exhibitions, and shop windows, and the support plate can be appropriately selected according to the intended use.

[0018] Figure 2 shows the layer configuration of the screen 10 according to the first embodiment. In Figure 2, a portion of the cross-section passing through point A (see Figure 1), which is the center of the screen (geometric center of the screen), is shown in an enlarged view. The cross-section is parallel to the vertical direction of the screen (Y direction) and perpendicular to the screen surface (parallel to the Z direction). Figure 3 is a diagram illustrating the first optical shape layer 12. In Figure 3, the first optical shape layer 12 is viewed from the back side (-Z side), and for ease of understanding, the reflective layer 13 and other components are omitted. As shown in Figure 2, the screen 10 comprises, in the thickness direction (Z direction), an optical control layer 16, a bonding layer 17a, a first substrate layer 11, a first optical shaping layer 12, a reflective layer 13, a second optical shaping layer 14, a second substrate layer 15, and so on, in order from the image source side (+Z side).

[0019] The first substrate layer 11 is a light-transmitting sheet-like member, and the first optical shaping layer 12 is integrally formed on its back side (-Z side). This first substrate layer 11 is the base layer for forming the first optical shaping layer 12. The first base material layer 11 is formed from, for example, a polyester resin such as PET (polyethylene terephthalate) which has high light transmittance, an acrylic resin, a styrene resin, an acrylic-styrene resin, a PC (polycarbonate) resin, an alicyclic polyolefin resin, a TAC (triacetylcellulose) resin, or the like.

[0020] The first optical shape layer 12 is a light-transmitting layer formed on the back side (-Z side) of the first substrate layer 11. Multiple unit optical shapes (unit lenses) 121 are arranged on the back side (-Z side) surface of the first optical shape layer 12. As shown in Figure 3, the unit optical shape 121 is a partial shape (arc-shaped) of a perfect circle, and multiple units are arranged concentrically around point C, which is located outside the screen (display area) of the screen 10. In other words, the first optical shape layer 12 has a circular Fresnel lens shape with a so-called offset structure, centered at point C (Fresnel center), on its back side. In this embodiment, as shown in Figure 3, when the first optical shape layer 12 is viewed from the back side (-Z side) along the normal direction of the screen surface, point C is located in the center of the screen in the left-right direction and below the screen, and point C and point A are located on the same straight line extending in the Y direction.

[0021] As shown in Figure 2, the unit optical shape 121 has a cross-sectional shape that is approximately triangular in a cross-section parallel to the direction perpendicular to the screen surface (Z direction) and parallel to the arrangement direction of the unit optical shapes 121. The unit optical shape 121 is convex on the back side (-Z side) and has a first slope (lens surface) 121a into which the image light is incident, and a second slope (non-lens surface) 121b that intersects it. In one unit optical shape 121, the first slope 121a is located above (+Y side) the second slope 121b, with vertex t1 in between. The angle that the first inclined plane 121a makes with a plane parallel to the screen plane (XY plane) is α. The angle that the second inclined plane 121b makes with a plane parallel to the screen plane is β. The angles α and β satisfy the relationship β > α.

[0022] Furthermore, the first and second bevel surfaces 121a and 121b of the unit optical shape 121 have fine and irregular uneven surfaces. These uneven surfaces are formed by an irregular arrangement of convex and concave shapes in a two-dimensional direction, and the size, shape, height, etc., of the convex and concave shapes are irregular.

[0023] The array pitch of the unit optical shapes 121 is P, and the height of the unit optical shapes 121 (the dimension from the vertex t1 in the thickness direction to the bottom of the valley between the unit optical shapes 121, point t2) is h. For ease of understanding, Figure 2 and other figures show the array pitch P and angles α and β of the unit optical shape 121 as constant in the array direction of the unit optical shape 121. However, in this embodiment, the array pitch P of the unit optical shape 121 is actually constant, but the angle α gradually (continuously) increases as it moves away from point C, which is the Fresnel center in the array direction of the unit optical shape 121 (as it moves upward in the cross-section shown in Figure 2).

[0024] However, the configuration is not limited to this; for example, the array pitch P may gradually change along the array direction of the unit optical shape 121, or the array pitch P, angle α, etc., may change in steps along the array direction of the unit optical shape 121. The angles α and β, the array pitch P, etc., may be set appropriately according to the projection angle of the image light from the image source LS (the angle of incidence of the image light onto the screen 10), the size of the pixels of the image source LS, the screen size of the screen 10, the refractive index of each layer, etc.

[0025] In this embodiment, an example is shown in which a circular Fresnel lens shape is formed on the back surface (-Z side) of the first optical shape layer 12. However, the embodiment is not limited to this, and a linear Fresnel lens shape may be formed on the back surface of the first optical shape layer 12 in which unit optical shapes 121 extend in the left-right direction (X direction) of the screen and are arranged in the up-down direction (Y direction) of the screen. Alternatively, a configuration may be provided in which multiple unit prisms, each having a roughly triangular cross-sectional shape and extending in the left-right direction (X direction) of the screen with the ridge line in the direction of the edge, are arranged in the up-down direction (Y direction) of the screen.

[0026] The first optical shaping layer 12 is formed from an ultraviolet-curable resin with high light transmittance, such as a urethane acrylate, polyester acrylate, epoxy acrylate, polyether acrylate, polythiol, or butadiene acrylate. In this embodiment, an ultraviolet-curable resin is used as an example to describe the resin constituting the first optical shape layer 12, but it is not limited to this, and may be formed using other ionizing radiation-curable resins such as electron beam-curable resins.

[0027] The reflective layer 13 is a semi-transparent reflective layer that reflects a portion of the incident light and transmits a portion of it; it is a so-called half-mirror. The reflective layer 13 is formed on the unit optical shape 121, that is, on the first bevel surface 121a and the second bevel surface 121b. This reflective layer 13 is provided between the first optical shape layer 12 and the second optical shape layer 14, adjacent to them. The reflective layer 13 has a rough surface with fine and irregular irregularities on its image source side (the side facing the first optical shape layer 12) and its back side (the side facing the second optical shape layer 14). This is because, as mentioned above, the first bevel surface 121a and the second bevel surface 121b have fine irregularities, the reflective layer 13 is formed to follow these fine irregularities, and the thickness of the reflective layer 13 is sufficiently thinner than the irregularities of these fine irregularities. This reflective layer 13 has the function of diffusely reflecting a portion of the incident light due to its fine and irregular uneven surface, and transmitting at least a portion of the other light that is not reflected without diffusion.

[0028] The reflectance and transmittance of the reflective layer 13 can be appropriately set according to the desired optical performance. From the viewpoint of reflecting image light well and transmitting light other than image light (for example, light from the outside such as sunlight) well, it is desirable that the reflectance and transmittance of the reflective layer 13 be approximately 30-80% for transmittance and 5-60% for reflectance.

[0029] The reflective layer 13 is formed from a highly light-reflective metal, such as aluminum, silver, nickel, or chromium. However, the reflective layer 13 is not limited to these, and may also be formed by, for example, sputtering a highly light-reflective metal as described above, transferring a metal foil, or applying a paint containing a thin metal film. Furthermore, the reflective layer 13 may be formed by depositing a dielectric multilayer film or dielectric monolayer film that has high transparency, low light absorption loss, and can achieve high reflectivity. The reflective layer 13 in this embodiment is formed by depositing chromium, and the reflectivity of the reflective layer 13 alone is approximately 5%, and the transmittance is approximately 50%. In this embodiment, the reflective layer 13 is shown to be formed on the first bevel surface 121a and the second bevel surface 121b of the unit optical shape 121. However, it is not limited to this, and for example, it may be formed on at least a part of the first bevel surface 121a.

[0030] The second optical shape layer 14 is a light-transmitting layer provided adjacent to the back side (-Z side) of the reflective layer 13. This second optical shape layer 14 is filled so as to sufficiently fill the valleys between adjacent unit optical shapes 121, and the back surface of the second optical shape layer 14 is a flat surface parallel to the screen surface. This second optical shaped layer 14 improves the light transmittance of the screen 10 and protects the reflective layer 13. Furthermore, the provision of the second optical shaped layer 14 facilitates the lamination of the second substrate layer 15 and other components.

[0031] From the viewpoint of improving the transparency of the screen 10, it is preferable that the refractive index of the second optical shaping layer 14 is equal to that of the first optical shaping layer 12, or has a refractive index difference small enough to be considered equal. Furthermore, the second optical shaping layer 14 may be formed using the same resin as the first optical shaping layer 12, or it may be formed using a different resin. The second optical shaping layer 14 in this embodiment is formed from the same UV-curable resin as the first optical shaping layer 12, and its refractive index is also the same as that of the first optical shaping layer 12.

[0032] The second base material layer 15 is a light-transmitting sheet-like member and is integrally laminated on the back side of the second optical shape layer 14. Similar to the first base material layer 11, this second base material layer 15 is formed from, for example, a polyester resin such as PET (polyethylene terephthalate), an acrylic resin, a styrene resin, an acrylic-styrene resin, a PC (polycarbonate) resin, an alicyclic polyolefin resin, a TAC (triacetylcellulose) resin, etc., which have high light transmittance. In this embodiment, the second base layer 15 is formed from the same material as the first base layer 11.

[0033] The bonding layer 17a is a layer that has the function of integrally bonding the light control layer 16 and the first substrate layer 11. The bonding layer 17a can be made of an adhesive or tack material with high light transmittance. The optical control layer 16 is located on the image source side (+Z side) of the first substrate layer 11 in the thickness direction, and has the function of diffusing and transmitting light incident from a specific angular range, and transmitting light incident from other angular ranges without diffusion. This optical control layer 16 is integrally provided on the image source side (+Z side) of the first substrate layer 11 via a bonding layer 17a. Figure 4 illustrates the optical control function of the optical control layer 16. Figure 4 shows a cross-section of the optical control layer 16 parallel to the vertical direction (Y direction) and the thickness direction (Z direction) of the screen. In Figure 4, the surface on the image source side (+Z side) and the back side (-Z side) of the optical control layer 16 are parallel to the screen surface (XY plane), and the dashed line H is a straight line perpendicular to the surface on the image source side and the back side of the optical control layer 16.

[0034] The optical control layer 16 has the function of diffusing light incident from the air on the image source side (+Z side) at an incident angle within the first incident angle range R1 and emitting it to the back side (-Z side), and transmitting light incident at an incident angle within the second incident angle range R2, which is an incident angle other than the first incident angle range R1, to the back side without diffusion. Furthermore, the optical control layer 16 has the function of diffusing light incident from the air on the back side (-Z side) at an incident angle within the third incident angle range R3 and emitting it to the image source side (+Z side), and transmitting light incident at an incident angle within the fourth incident angle range R4, which is an incident angle other than the third incident angle range R3, to the image source side without diffusion.

[0035] The first incidence angle range R1 includes the main incidence angle range of the image light L0 projected from the image source LS and incident on the screen 10 (optical control layer 16). The first incident angle range R1 is the range on the image source side (+Z side) where the angle is between 25° and 55° below the straight line H (-Y side). At this time, the light control layer 16 diffuses light incident from the lower side of the screen in the vertical direction at an incident angle of 25° to 55° to any point on its surface on the image source side and emits it to the back side (-Z side). Furthermore, the second incident angle range R2 is an angle other than the first incident angle range R1 on the image source side of the optical control layer 16.

[0036] The third incident angle range R3 is the range on the back side (-Z side) where the angle is between 25° and 55° above the line H (+Y side). At this time, the light control layer 16 diffuses light incident from the upper side in the vertical direction of the screen at an incident angle of 25° to 55° to any point on its back surface and emits it towards the image source side (+Z side). Furthermore, the fourth incident angle range R4 is an angle other than the third incident angle range R3 on the back side of the optical control layer 16.

[0037] Therefore, the optical control layer 16 diffuses and transmits light incident from the lower side of the screen at an incident angle of 25° to 55° at any point on the surface facing the image source, while transmitting light incident from other angles without diffusion. Furthermore, the optical control layer 16 diffuses and transmits light incident from the upper side of the screen at an incident angle of 25° to 55° at any point on the surface facing the back, while transmitting light incident from other angles without diffusion.

[0038] It is preferable that the haze value (diffuse transmittance) of light incident on the optical control layer 16 from the image source side at an incident angle within the first incident angle range R1 and emitted to the back side be 80% or more. It is also preferable that the haze value of light incident on the optical control layer 16 from the back side at an incident angle within the third incident angle range R3 and emitted to the image source side be the same. The haze value is expressed as the ratio of diffuse transmittance to total transmittance and represents the diffusivity of light in transmitted light. The haze value of the light control layer 16 can be measured using a haze meter (for example, HM-150 manufactured by Murakami Color Technology Laboratory).

[0039] For incident light within the ranges of the first incident angle range R1 and the third incident angle range R3, since the first incident angle range R1 and the third incident angle range R3 in this embodiment are 25° or more and 55° or less, the assumed incident angle is set to 40°, the transmittance when light is incident at this angle is defined as the total light transmittance, and the ratio of light that spreads out at 2.5° or more to the light that is incident at this assumed incident angle, travels straight through the light control layer 16 and is emitted is defined as the diffuse transmittance.

[0040] On the other hand, the haze value (diffuse transmittance) of light incident on the optical control layer 16 from the image source side at an incident angle within the second incident angle range R2, and especially light incident at an incident angle of 0° and emitted to the back side, is preferably low, and ideally 0%. The haze value of light incident on the optical control layer 16 at an incident angle within the fourth incident angle range R4 is also preferably similar.

[0041] As such a light control layer 16, a field of view control film (for example, Lintec Corporation's field of view control film Y-2555) is preferred, which is formed by laminating multiple layers of transparent resin with different refractive indices in a predetermined thickness and direction, and by changing the direction of ultraviolet irradiation during the curing of each layer.

[0042] As described above, the screen 10 of this embodiment does not have a light diffusion layer containing a diffusing material such as particles that have the effect of diffusing light. Instead, only light incident at an incident angle within a specific angular range (first incident angle range R1 and third incident angle range R3) is diffused in the light control layer 16, and further diffuse reflection occurs in the reflective layer 13 due to the fine irregularities on its surface. In this embodiment, the combined thickness of the bonding layer 17a and the first substrate layer 11, that is, the distance D1 between the image source side (+Z side) of the first optical shape layer 12 and the back side (-Z side) of the light control layer 16 in the thickness direction (Z direction) of the screen 10, is preferably 0.5 mm or less. If the size of this distance D1 is greater than 0.5 mm, the distance between the light control layer 16 that diffuses the image light and the reflective layer 13 that diffusely reflects the image light becomes too large, resulting in increased blurring of the image and a decrease in image clarity. Therefore, the above range is preferred for the distance D1.

[0043] Figure 5 shows an example of the image light and ambient light incident on the screen 10 of the first embodiment. In Figure 5, a portion of the same cross-section as the cross-section of the screen 10 shown in Figure 2 is shown in enlargement. Also, in Figure 5, for ease of understanding, it is shown that there is no difference in refractive index between each layer. The image light L11 projected from the image source LS located below the screen 10 enters the optical control layer 16 at an incident angle within the first incident angle range R1, is diffused, passes through the bonding layer 17a and the first substrate layer 11, and enters the first optical shape layer 12. Then, the image light L12, which is a part of the image light L11, is diffusely reflected by the reflective layer 13 of the first bevel surface 121a of the unit optical shape 121 and exits towards the image source side (+Z side). At this time, in the cross-section of the screen 10 shown in Figure 5, the image light L12 enters the optical control layer 16 from the back side at an incident angle corresponding to the fourth incident angle range R4 (especially incident angles of 0° and near 0°), so it exits towards the image source side without being diffused in the optical control layer 16 and reaches the observer O1 side.

[0044] Therefore, the video light L12 is incident on the light control layer 16 within the range of the first incident angle R1 and is diffusely reflected by the reflective layer 13. As a result, the video light L12 is appropriately diffused, and the screen 10 can display the image with a sufficient viewing angle. Furthermore, the image light L12 is diffused by the light control layer 16 when it enters the screen 10 and diffusely reflected by the reflection layer 13, so it is diffused twice at different positions in the thickness direction of the screen 10. As a result, the screen 10 can reduce glare (speckle) in the image and suppress image blurring (reduction in resolution) due to excessive diffusion.

[0045] Furthermore, since the image light L11 is projected from below the screen 10, and the angle β (see Figure 2) is greater than the angle of incidence of the image light L11 at each point in the vertical direction (Y direction) of the screen 10, the image light L11 does not directly enter the second slope 121b, and the second slope 121b does not contribute to the reflection of the image light. Furthermore, some of the image light L13 of the image light L11 passes through the reflective layer 13 and heads toward the back side, and passes through the second optical shaping layer 14 and is emitted upward toward the back side. If such image light L13 reaches the ceiling on the back side, it can cause the image to be reflected on the ceiling. However, in the screen 10 of this embodiment, the image light L13 is diffused by the light control layer 16, so even if the image light L13 reaches the ceiling, a clear image will not be reflected on the ceiling.

[0046] Next, we will explain the external light other than video light that enters the screen 10 from the rear side (-Z side) or the video source side (+Z side), such as sunlight or illumination light. The majority of the ambient light G11 and G12, which have a small incident angle to the screen 10, enter the screen 10, pass through the reflective layer 13, and exit towards the back side and the image source side, respectively. The screen 10 does not have a layer containing diffusing material such as particles that diffuse light (light diffusion layer). The ambient light G11 enters the light control layer 16 from the image source side at an incident angle within the second incident angle range R2, and the ambient light G12 enters the light control layer 16 from the back side at an incident angle corresponding to an angle within the fourth incident angle range R4. Therefore, the ambient light G11 and G12 pass through the screen 10 without being diffused by the light control layer 16. Therefore, when observers O1 and O2 observe the scenery on the other side of screen 10 through screen 10, they can observe the scenery on the other side of screen 10 without it becoming blurred or smeared white, and screen 10 can exhibit high transparency.

[0047] Next, of the ambient light G13 incident on the screen 10 from above on the image source side, some of the ambient light (not shown) is reflected by the surface of the screen 10 and heads downwards on the screen, not reaching the observers O1 and O2. Also, since the ambient light G13 is incident on the light control layer 16 from the image source side at an incident angle within the second incident angle range R2, it passes through the light control layer 16 without diffusion and heads towards the back side inside the screen 10. Of the ambient light G13, some of the ambient light G14 is reflected by the reflective layer 13 and heads downwards on the image source side of the screen 10, either emitting downwards on the image source side of the screen 10 or undergoing total internal reflection on the surface of the screen 10 on the image source side and heading downwards again inside the screen 10, where it is attenuated. Also, some of the ambient light G15 of the ambient light G13 passes through the reflective layer 13 and emits downwards on the back side of the screen 10, not reaching the observers O1 and O2.

[0048] Of the ambient light G16 incident on the screen 10 from the upper rear side, some of the ambient light (not shown) is reflected by the surface of the screen 10 and heads downwards, not reaching the observers O1 and O2. Also, some of the ambient light G17 is incident on the screen 10 and diffusely reflected by the reflective layer 13, but it exits upwards on the rear side, so it does not reach the observers O1 and O2. Furthermore, some of the ambient light G18 is transmitted through the reflective layer 13 and exits downwards towards the image source. Depending on the angle at which this ambient light G18 is incident on the light control layer 16 from the rear side, it may be diffused by the light control layer 16, but it exits downwards on the screen 10 and does not reach the observers O1 and O2, so the effect of diffusion on the image contrast is small. Therefore, the screen 10 can suppress the reduction in image contrast caused by ambient light entering from above the image source side or from above the back side.

[0049] In conventional reflective screens, the screen 10 of this embodiment is equipped with a light-diffusing layer containing a diffusing material such as light-diffusing particles at a position corresponding to the light control layer 16. As a result, the image light is diffused twice by the light-diffusing layer—once before and after reflection in the reflective layer, and again by the light-diffusing layer—in addition to diffuse reflection in the reflective layer. This causes excessive diffusion of the image light, resulting in blurring of the image (reduced resolution). In contrast, according to this embodiment, the video light is not diffused after diffuse reflection in the reflective layer 13, so a high-resolution image can be displayed.

[0050] Furthermore, in conventional reflective screens equipped with such a light-diffusing layer, unwanted ambient light is also diffused by the light-diffusing layer. As a result, when observers O1 and O2 observe the scenery beyond the screen 10 through the screen 10, the scenery beyond the screen 10 appears blurred or smeared white, reducing the transparency of the screen and decreasing the contrast of the image. In contrast, according to this embodiment, the screen 10 does not have such a light-diffusing layer, and most of the ambient light passes through the screen without being diffused, or even if it is diffused, it is emitted outside the range visible to observers O1 and O2, as shown in Figure 5. Therefore, when observers O1 and O2 observe the scenery on the other side of the screen 10 through the screen 10, the scenery on the other side of the screen 10 does not become blurred or smeared with white, the transparency of the screen can be maintained, and the reduction in image contrast due to the diffusion of ambient light can be significantly suppressed.

[0051] Based on the above, this embodiment can suppress glare in the image and suppress blurring (reduction in resolution) in the image, thereby displaying a clear image. Furthermore, according to this embodiment, since unwanted ambient light is diffused and does not reach the observer, it is possible to display images with high contrast and to create a highly transparent screen. Furthermore, according to this embodiment, it is possible to suppress the reflection of images onto the ceiling and other surfaces caused by image light transmitted through the reflective layer 13.

[0052] (Evaluation regarding image glare, etc.) Here, a screen corresponding to the embodiment of screen 10 of this embodiment and a comparative example screen were prepared and evaluated in terms of the effect of reducing image glare and the clarity of the image. The screens in the examples and comparative examples 1 and 2 all have a screen size of 40 inches. The light control layer 16 in this embodiment is a field of view control film Y-2555 manufactured by Lintec Corporation.

[0053] The screen of Comparative Example 1 comprises a first substrate layer 11, a first optical shaping layer 12, a reflective layer 13, a second optical shaping layer 14, and a second substrate layer 15, similar to the screen 10 of the embodiment, but lacks a bonding layer 17a and an optical control layer 16. The screen of Comparative Example 2 corresponds to a configuration in which, compared to the screen of Comparative Example 1, a light diffusion layer is laminated on the image source side of the first substrate layer 11 via a bonding layer 17a, instead of the light control layer 16. This light diffusion layer is a resin layer containing light-diffusing particles and has the characteristic of diffusing light regardless of the angle of incidence of the light. Therefore, while the first substrate layer 11 to the second substrate layer 15 are the same in form as the screen of the example and the screens of comparative examples 1 and 2, the presence or absence of the light control layer 16 is a point of difference.

[0054] The details of the common layer in the screens of the Examples and Comparative Examples 1 and 2 are as follows. The first base layer 11 is made of polycarbonate resin with a refractive index of 1.59 and has a thickness of 0.075 mm. The first optical shape layer 12 is made of an ultraviolet-curable resin (urethane acrylate) with a refractive index of 1.51. Its thickness varies in the direction of the arrangement of the unit optical shapes 121, depending on the height h of the unit optical shapes 121, but is 0.01 mm at the center of the bottom edge of the screen and 0.14 mm at the center of the top edge of the screen.

[0055] The reflective layer 13 is made of chromium and has a thickness of several nanometers. The second optical shape layer 14 is made of an ultraviolet-curable resin (urethane acrylate) with a refractive index of 1.51. Its thickness varies in the direction of the arrangement of the unit optical shapes 121, depending on the height h of the unit optical shapes 121, but is 0.14 mm at the center of the bottom edge of the screen and 0.01 mm at the center of the top edge of the screen. The second base layer 15 is made of polycarbonate resin with a refractive index of 1.59 and has a thickness of 0.075 mm.

[0056] For the screens of the Examples and Comparative Examples 1 and 2, speckle contrast, peak gain, peak brightness, total light transmittance, and haze value were measured, respectively. Furthermore, visual evaluation was performed to assess image glare and clarity, screen transparency, and the presence or absence of image reflections on the ceiling (so-called ceiling ghosting). In addition, the total light transmittance and haze value were measured for the light control layer 16 of the example screen and the light diffusion layer of Comparative Example 2, respectively. The following describes the measurement methods for speckle contrast, peak gain, peak brightness, total light transmittance, and haze value.

[0057] Figure 6 shows the positions of each screen, the image source LS, the luminance meter K, and the observer O3 during peak brightness measurement and visual evaluation. Figure 6(a) shows the positions of each screen, image source LS, luminance meter K, and observer O3 as viewed from the side (+X side) during peak luminance measurement. Figure 6(b) shows the positions of each screen, image source LS, luminance meter K, and observer O3 as viewed from above (+Y side) during peak luminance measurement. Note that in Figure 6, the positions of the luminance meter K and observer O3 are shown shifted in the Z direction for ease of understanding.

[0058] Speckle contrast is the value obtained by dividing the standard deviation σ of the surface light intensity distribution in a given area by the mean value I of the surface light intensity distribution in a given area when monochromatic light is shone onto a screen. The smaller this value, the less speckle is considered to be. According to the NEDO (New Energy and Industrial Technology Development Organization) guidelines for speckle contrast, speckle is considered easily visible to the human eye when the speckle contrast is 0.05 or higher for red and green light, and 0.08 or higher for blue light. Here, the speckle contrast was measured using a measuring instrument (Dr.SPECKLE / SM01VS09 manufactured by Oxide Co., Ltd.) in accordance with the international standard IEC 62906-5-2 / 62906-5-4, with a green screen projected from the image source LS onto the entire surface of the screens of Example and Comparative Examples 1 and 2. The measurement was taken from a position 800 mm from point A, the center of each screen, toward the image source side (+Z side), using the above measuring instrument, with an exit pupil angle of 1 degree. The speckle contrast of this green light will be referred to as the speckle contrast Cs(G) below.

[0059] The method for calculating peak gain is as follows: First, the screens of the Examples and Comparative Examples 1 and 2 were placed in a darkroom environment, and a white screen was projected onto the entire surface using an image source LS (PJWX-4152N, manufactured by Ricoh Co., Ltd.). As shown in Figure 6, the luminance at point A, which is the center of the screen, was measured using a luminance meter K (BM-9, manufactured by Topcon Corporation) from a position 1 m in the +Z direction relative to point A. The measurement with the luminance meter K was performed by fine-tuning the position of the luminance meter K to set the position where the highest luminance could be obtained, and the maximum luminance Lmax (cd / m²) was determined. 2 The following was measured. The installation position of the video source LS was in accordance with the instruction manual for the video source LS used, and in the cross-section shown in Figure 6(a), the incident angle θ of the video light at point A is θ = 50°. Next, an illuminance meter (Topcon IM-600) was used to measure the illuminance Iw (lx) at point A, which is the center of the screen, when a white image was projected. The gain G was calculated using the following formula based on the obtained values. G = Lmax × π / Iw The resulting gain G corresponds to the peak gain. The peak brightness is defined as the maximum brightness obtained from the above measurement.

[0060] For the total light transmittance and haze value, a 10 cm square-shaped component with sides parallel to the left-right and up-down directions of the screen, centered at point A, which is the center of the screen in Examples and Comparative Examples 1 and 2, was cut out as a sample for each screen, and the total light transmittance and haze value at point A were measured using this sample. Total light transmittance is the transmittance of light incident at an incident angle of 0°. Total light transmittance was measured using a screen sample and a haze meter (HM-150, manufactured by Murakami Color Research Institute Co., Ltd.) in accordance with JIS K7316. During measurement, the sample was positioned so that the side of the screen facing the image source (observer side) in its usage state was facing the sensor side of the haze meter.

[0061] As mentioned above, the haze value is the ratio of diffuse transmittance to total transmittance for light incident at an incident angle of 0°. It was measured using a haze meter (HM-150 manufactured by Murakami Color Research Institute Co., Ltd.) in accordance with JIS K7316, using samples of each screen. During measurement, the sample was positioned so that the side of the screen facing the image source (observer side) in its usage state was facing the sensor side of the haze meter. Furthermore, the total light transmittance and haze value were measured for the light control layer 16 of the example screen and the light diffusion layer of the comparative example 2 screen using the method described above.

[0062] Furthermore, visual evaluations were conducted on the screens of the example and comparative examples 1 and 2 to check for glare, clarity, transparency, and reflection of images on the ceiling. Regarding image glare, for the screens of the Examples and Comparative Examples 1 and 2, in a darkroom environment, with a white screen projected from the image source LS, observer O3 observed and evaluated the central part of each screen from a position 1m away from point A, which is the center of the screen, on the image source side (+Z side).

[0063] Regarding the clarity of the image, in a darkroom environment, a still image (white text on a black background) was projected from the image source LS onto the screens of the Examples and Comparative Examples 1 and 2. Observer O3 observed and evaluated the central part of the screen from a position 1m away from point A, which is the center of the screen, on the image source side (+Z side). Regarding screen transparency, under bright room conditions (illuminance of 700 lx at point A, the center of the screen), and without projection of image light from the image source, observer O3 observed and evaluated the central part of each screen from a position 1 m away from point A, the center of the screen, towards the image source (+Z side).

[0064] The presence or absence of image reflections on the ceiling (so-called ceiling ghosting) was evaluated by projecting a still image (white text on a black background) from the image source LS onto the screens of the example and comparative examples 1 and 2 in a darkroom environment. The image light that passed through each screen reached the ceiling located 1.5m above (+Y) on the back side (-Z side) of each screen and was observed and evaluated. At this time, since there was an open space between each screen and the ceiling, observer O3 observed and evaluated the ceiling from a position 1m from point A, which is the center of the screen, towards the image source side (+Z side). Note that in each evaluation, there were three observers (O3), and the evaluation results were based on their average.

[0065] [Table 1]

[0066] Table 1 shows the evaluation results of the screens for the Examples and Comparative Examples 1 and 2. Table 1 also lists the transmittance and haze of the light control layer 16 and light diffusion layer used in Examples and Comparative Example 2. In Table 1, glare is indicated as follows: ◎ indicates good if no glare is visible in the image; ○ indicates acceptable if some glare is visible but within a tolerable range; and × indicates unacceptable if glare is visible and unpleasant. In Table 1, image clarity was indicated as follows: ◎ for clear images with no blurring, ○ for images that were sufficiently clear despite some blurring, and × for images that were blurry and unsuitable for use.

[0067] In Table 1, transparency is indicated as follows: ◎ for high transparency (good), ○ for transparency that is slightly less transparent than good but still sufficient for use (acceptable), and × for transparency that is poor, such as when the other side of the screen appears cloudy or whitish. Furthermore, in Table 1, the presence or absence of reflections of images on the ceiling (so-called ceiling ghosting) is indicated as follows: ◎ indicates good if the projected image pattern on the ceiling is not recognizable due to the image light transmitted through the screen; ○ indicates good if the image pattern is recognizable but unclear compared to good; and × indicates poor if the image pattern is clearly recognizable.

[0068] The overall evaluation for each screen took into account all factors, including speckle contrast Cs(G), peak gain, peak brightness, transmittance, visual evaluation of image glare and clarity, screen transparency, and reflection of images on the ceiling. Screens with reduced glare, clear images, sufficient transparency, and no visible reflections on the ceiling were marked as "Good" (◎), screens that were less than "Good" but still usable were marked as "Acceptable" (〇), and screens unsuitable for use were marked as "Unacceptable" (×).

[0069] As shown in Table 1, in the screen of Comparative Example 1, which does not have a light control layer 16 on the image source side of the first substrate layer 11, the peak gain and brightness are high and the image brightness is sufficient, the image is clear and the transparency is good, but glare occurs in the image, which is undesirable. In addition, in the screen of Comparative Example 1, the reflection of the image on the ceiling on the back side of the screen is visible, which is undesirable. Furthermore, in the screen of Comparative Example 2, which has a light diffusion layer on the image source side of the first substrate layer 11, the speckle contrast Cs(G) was the smallest, and the glare of the image was effectively suppressed in visual evaluation. However, in the screen of Comparative Example 2, the peak gain and brightness decreased, making the image darker, and the image was unclear (large image blur) in visual evaluation, and the transparency was also greatly reduced. This is thought to be because the light diffusion layer diffuses light regardless of the angle of incidence of light, so ambient light such as illumination light is also diffused. In addition, in the screen of Comparative Example 2, the reflection of the image on the ceiling on the back side of the screen was also visible.

[0070] In contrast, the screen in this example has a speckle contrast Cs(G) of less than 0.05, and visual evaluation shows that it has sufficiently reduced image glare. Furthermore, sufficient peak gain and peak brightness are ensured, and visual evaluation shows that the image is clear, the transparency is sufficient, and no reflection of the image onto the ceiling on the back side of the screen was observed.

[0071] Based on the above, this embodiment provides a screen 10 and an image display device 1 that can display clear images and reduce image glare. Furthermore, according to this embodiment, while having the effects described above, sufficient transparency of the screen 10 can also be ensured. Moreover, according to this embodiment, reflections of images onto the ceiling on the back side of the screen can also be suppressed.

[0072] (Second Embodiment) Figure 7 shows the layer configuration of the screen 20 in the second embodiment. In Figure 7, similar to Figure 2 of the first embodiment described above, a magnified view of a portion of the cross-section passing through the center of the screen 20 (the geometric center of the screen) (corresponding to point A in Figure 1), parallel to the vertical direction of the screen (Y direction), and perpendicular to the screen surface (parallel to the Z direction). The screen 20 of the second embodiment differs from the screen 10 shown in the first embodiment in that the thickness of the portion on the back side of the reflective layer 13 is greater, and a light-adjusting layer 30 is provided on the back side of the second substrate layer 25 via a bonding layer 17c. Otherwise, it has the same configuration as the first embodiment. Therefore, in the following description, parts that perform the same functions as those of the first embodiment are denoted by the same reference numerals or the same reference numerals at the end, and redundant explanations are omitted as appropriate.

[0073] As shown in Figure 7, the screen 20 of the second embodiment comprises, in the thickness direction (Z direction) of the screen 20, in order from the image source side (+Z side), an optical control layer 16, a bonding layer 17a, a first substrate layer 11, a first optical shaping layer 12, a reflective layer 13, a second optical shaping layer 14, a second substrate layer 25, a bonding layer 17c, and a dimming layer 30. This screen 20 can be applied to the image display device 1 in place of the screen 10 of the first embodiment. In the screen 20 of this embodiment, the combined thickness of the bonding layer 17a and the first substrate layer 11, that is, the distance D1 between the image source side (+Z side) of the first optical shape layer 12 and the back side (-Z side) of the light control layer 16 in the thickness direction (Z direction) of the screen 10, is preferably 0.5 mm or less from the viewpoint of reducing image blurring and the like.

[0074] The second base material layer 25 in this embodiment is thicker than the second base material layer 15 in the first embodiment and has sufficient rigidity to maintain the flatness of the screen surface of the screen 20. Therefore, the screen 20 can maintain sufficient flatness as a screen 20 even without being joined to a support plate or the like (not shown) as shown in the first embodiment. Furthermore, the flatness of the screen surface may be further improved by joining the support plate as described above to the back side of the screen 20 via a bonding layer (not shown). The second base material layer 25 is preferably a plate-shaped member made of, for example, a highly transparent acrylic resin, polycarbonate resin, or glass. The thickness of the second base material layer 25 is preferably about 3 to 8 mm and can be appropriately selected according to the screen size of the screen 20.

[0075] Furthermore, since the screen 20 of this embodiment is equipped with the second base material layer 25 as described above, in the thickness direction (Z direction), the distance D2 from the image source side (+Z side) surface of the dimming layer 30 to the back side (-Z side) surface of the second optical shape layer 14 is greater than the distance D1 from the back side (-Z side) surface of the light control layer 16 to the image source side (+Z side) surface of the first optical shape layer 12. In other words, the shortest distance from the image source side (+Z side) surface of the dimming layer 30 to the reflective layer 13 is greater than the shortest distance from the back side (-Z side) surface of the light control layer 16 to the reflective layer 13. This makes it possible to reduce the distance D1 while ensuring a thickness that maintains the flatness of the screen 20. Consequently, the distance from the light control layer 16 to the reflection layer 13 can also be reduced, so that the image light incident on the light control layer 16 at an incident angle within the first incident angle range R1 is diffused by the light control layer 16 and spreads out as it travels through the screen 20, thereby reducing image blurring such as double images caused by the reflection position at the reflection layer 13 being further away.

[0076] If a screen similar to the screen in this embodiment is provided with a second substrate layer 25 and does not have a dimming layer 30 described later, the thickness of the second substrate layer 25 will result in a greater thickness on the back side than the reflective layer 13. Therefore, in such a screen, the image light incident on the light control layer 16 at an angle within the first incident angle range R1 is diffused and spreads out as it moves towards the back side of the screen. Then, at the interface with the air on the back side of the screen, some of the image light undergoes total internal reflection and heads towards the image source, and when it is emitted from the screen towards the observer, it is perceived as image blur such as a double image, and the image quality deteriorates. Furthermore, as mentioned above, some of the video light that passes through the reflective layer 13 causes the image to be reflected onto the ceiling. To improve these aspects, the screen 20 of this embodiment is provided with a light-adjusting layer 30 on the back side (-Z side) of the second substrate layer 25.

[0077] The bonding layer 17c is a layer that has the function of integrally bonding the second base material layer 25 and the light-adjusting layer 30. Similar to the bonding layer 17a described above, the bonding layer 17c can use adhesives or tacks with high light transmittance.

[0078] The light-adjusting layer 30 is a light-absorbing layer that absorbs a portion of the incident light and transmits a portion of it. The light-adjusting layer 30 in this embodiment is a film that can control the amount of transmitted light by changing the applied voltage, and has the function of controlling the amount of transmitted light, i.e., the light transmittance, by absorbing at least a portion of the incident light. The light-adjusting layer 30 in this embodiment is a guest-host type liquid crystal cell using a dichroic dye, and is a liquid crystal cell that changes the amount of transmitted light by an electric field applied to the liquid crystal. The light-adjusting layer 30 is constructed by sandwiching the liquid crystal layer 36 between a film-like second laminate 30B for liquid crystal and a first laminate 30A for liquid crystal.

[0079] The second laminate 30B for liquid crystal is formed by laminating a transparent electrode 32B, an alignment layer 33B, and a bead spacer 34 onto a substrate 31B. The first laminate 30A for liquid crystal is formed by laminating a transparent electrode 32A and an alignment layer 33A onto a substrate 31A. The dimming layer 30 changes the orientation of the liquid crystal material made of the guest host liquid crystal composition provided in the liquid crystal layer 36 by driving the transparent electrodes 32A and 32B provided in the first liquid crystal laminate 30A and the second liquid crystal laminate 30B, thereby changing the amount of transmitted light.

[0080] Various transparent resin films can be applied to the substrates 31A and 31B, but it is desirable to apply a transparent resin film that has low optical anisotropy and a transmittance of 80% or more in the visible wavelength range (380-800 nm). Examples of materials for transparent resin films include acetylcellulose resins such as triacetylcellulose (TAC), polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin resins such as polyethylene (PE), polypropylene (PP), polystyrene, polymethylpentene, and EVA, vinyl resins such as polyvinyl chloride and polyvinylidene chloride, acrylic resins, polyurethane resins, polysulfone (PEF), polyethersulfone (PES), polycarbonate (PC), polysulfone, polyether (PE), polyetherketone (PEK), (meth)acronitrile, cycloolefin polymer (COP), and cycloolefin copolymer. As materials for transparent resin films, resins such as polycarbonate (PC), cycloolefin polymer (COP), and polyethylene terephthalate (PET) are particularly preferred. The base materials 31A and 31B can be fitted with transparent resin films of various thicknesses.

[0081] The transparent electrode (first electrode) 32A and the transparent electrode (second electrode) 32B are composed of a transparent conductive film laminated on a transparent resin film. As transparent conductive films, various transparent electrode materials applicable to this type of transparent resin film can be used, including transparent metal thin films with an oxide-based total light transmittance of 50% or more. Examples include tin oxide-based, indium oxide-based, and zinc oxide-based films.

[0082] Examples of tin oxide (SnO2)-based materials include NESA (tin oxide SnO2), ATO (Antimony Tin Oxide: antimond-doped tin oxide), and fluorine-doped tin oxide. Examples of indium oxide (In2O3) compounds include indium oxide, ITO (Indium Tin Oxide), and IZO (Indium Zinc Oxide). Examples of zinc oxide (ZnO)-based materials include zinc oxide, AZO (aluminum-doped zinc oxide), and gallium-doped zinc oxide. In this embodiment, a transparent conductive film is formed using ITO (Indium Tin oxide).

[0083] In this embodiment, a spherical bead spacer 34 is used as a spacer. The bead spacer 34 is provided to define the thickness (cell gap) of the liquid crystal layer 36, excluding the outer periphery. The bead spacer 34 can be made of a wide range of materials, including inorganic materials such as silica, organic materials, or a core-shell structure combining these. In addition to the spherical shape described above, the shape of the bead spacer 34 may also be a rod shape, such as a cylindrical or prismatic shape. However, the spacer that defines the thickness of the liquid crystal layer 36 is not limited to the bead spacer 34. For example, it may be made into a cylindrical shape or the like by coating a photoresist onto the substrate 31A or substrate 31B, exposing it, and developing it. In the above explanation, an example was shown in which the spacer is provided on the second liquid crystal laminate 30B. However, the spacer is not limited to this, and may be provided on both the first liquid crystal laminate 30A and the second liquid crystal laminate 30B, or only on the first liquid crystal laminate 30A.

[0084] The alignment layers 33A and 33B are films used to align liquid crystal molecules in a specific direction. For example, the alignment layers 33A and 33B may be in the state of alignment films themselves, or they may be fabricated by performing alignment treatments such as photo-alignment treatment or rubbing treatment, or they may be fabricated by forming fine line-like irregularities. The method for fabricating the alignment layers 33A and 33B is not limited to the methods described above, and other methods may be used as appropriate. In this embodiment, the rubbing polyimide resin layer is used as the orientation layer 33A, 33B. Furthermore, although this embodiment shows the dimming layer 30 to include alignment layers 33A and 33B, it is not limited to this configuration, and may also be configured without alignment layers 33A and 33B.

[0085] A guest-host liquid crystal composition using a dichroic dye composition can be widely applied to the liquid crystal layer (liquid crystal material as a light-adjusting material) 36. The guest-host liquid crystal composition may contain a chiral agent so that when the liquid crystal material is horizontally oriented (oriented parallel to the planar direction of the light-adjusting layer 30 and perpendicular to the thickness direction of the liquid crystal layer 36), it forms a spiral shape in the thickness direction of the liquid crystal layer 36. In the light-adjusting layer 30, a sealing material 35 is arranged so as to surround the liquid crystal layer 36. This sealing material 35 holds the first liquid crystal laminate 30A and the second liquid crystal laminate 30B together and prevents leakage of the liquid crystal material. The sealing material 35 can be, for example, a thermosetting resin such as epoxy resin or acrylic resin, or an ultraviolet-curing resin.

[0086] The light-adjusting layer 30 is configured such that the orientation of the guest host liquid crystal composition when light is blocked is formed in the absence of an electric field. The alignment layers 33B and 33A are configured as horizontal alignment layers with orientation restricting forces related to pre-tilt in a certain direction, thereby forming a normally dark layer. Here, "normally dark" refers to a structure where the transmittance is minimized when no voltage is applied to the liquid crystal, resulting in a black screen. "Normally clear" refers to a structure where the transmittance is maximized when no voltage is applied to the liquid crystal, resulting in a transparent screen. The dimming layer 30 may also be constructed using a normally clear structure such that its orientation in the light-shielding state is formed when voltage is applied.

[0087] In this embodiment, the light-adjusting layer 30 is a guest-host type liquid crystal cell, but it may also be configured as a liquid crystal cell that does not use a dichroic dye composition. In this case, by further providing a linear polarization layer, it can function as a light-adjusting cell. Furthermore, various driving methods for liquid crystals are known, such as the TN (Twisted Nematic) method, the VA (Vertical Alignment) method, and the IPS (In-Plane-Switching) method, and these known driving methods can be appropriately selected and used.

[0088] Figure 8 shows the orientation of the liquid crystal material in the light-adjusting layer 30. For ease of understanding, Figure 8 shows only the transparent electrodes 32A, 32B and the alignment layers 33A, 33B, and the liquid crystal material (liquid crystal composition 36a and dichroic dye 36b). Figure 8(a) shows the state when light is blocked (no voltage applied), and Figure 8(b) shows the state when light is transmitted (voltage applied). Since the light-adjusting layer 30 of this embodiment is normally dark, as shown in Figure 8(a), when no voltage is applied (no electric field), the liquid crystal composition 36a and the dichroic dye 36b are aligned horizontally in one direction, that is, the long axis direction of the liquid crystal composition 36a and the dichroic dye 36b is in one direction and is parallel to the transparent electrodes 32A, 32B and the alignment layers 33A, 33B (so-called horizontal direction). In this state, regardless of the angle of incidence, most of the light incident on the light-adjusting layer 30 (light La, Lb shown in Figure 8(a)) is absorbed by the dichroic dye 36b, resulting in a light-shielding state with minimum transmittance.

[0089] Furthermore, since the dimming layer 30 of this embodiment is normally dark, as shown in Figure 8(b), when a voltage is applied (when an electric field is applied), the liquid crystal composition 36a and the dichroic dye 36b are aligned perpendicularly in one direction, that is, the long axis direction of the liquid crystal composition 36a and the dichroic dye 36b is in one direction and is oriented perpendicular to the transparent electrodes 32A, 32B and the alignment layers 33A, 33B (so-called perpendicular direction). In this state, of the light incident on the dimming layer 30, light La incident at a small incident angle, such as 0° or near 0°, is transmitted through the liquid crystal layer 36 (dimming layer 30). However, as the incident angle increases, the absorption rate of light by the dichroic dye increases, and much of the light Lb incident on the dimming layer 30 from an oblique direction at a large incident angle is absorbed by the dichroic dye 36b, causing a significant decrease in transmittance. In other words, the light-adjusting layer 30 has a higher absorption rate for light incident at large angles of incidence than for light incident at small angles of incidence, such as 0° or near 0°. Therefore, when a voltage is applied, the light-adjusting layer 30 has high transmittance of light in the direction parallel to its thickness (Z direction), and its transmittance decreases as the angle of incidence increases, and its transmittance is low for light incident at a large angle of incidence from an oblique direction relative to the thickness direction. In this embodiment, this state of the light-adjusting layer 30 is called the light-transmitting state. In this embodiment, a large incident angle is defined as an incident angle of 40° or more.

[0090] By providing such a dimming layer 30, the following effects can be achieved. When the dimming layer 30 is in a light-blocking state, it absorbs a lot of light regardless of the angle of incidence, resulting in a black screen. Therefore, by blocking the dimming layer 30 and projecting image light from the image source LS onto the screen 20, the black brightness of the image can be reduced, and the contrast of the image can be greatly improved. Furthermore, if the screen 20 does not have a dimming layer 30, the image light transmitted through the reflective layer 13 may undergo total internal reflection at the air interface on the back side of the screen 20 and be emitted from the side facing the image source, potentially causing image blurring such as double images. However, the screen 20, with its dimming layer 30, can absorb the image light that causes such double images, significantly suppressing image blurring and enabling the display of clear images. Furthermore, the dimming layer 30 absorbs the image light that passes through the reflective layer 13 and is directed upward on the back side of the screen 20, thereby significantly suppressing the reflection of the image onto the ceiling on the back side of the screen 20.

[0091] Next, when the light-adjusting layer 30 is in a light-transmitting state, the light-adjusting layer 30 can absorb much of the external light, such as sunlight and lighting, that enters the screen 20 from above on the back side at a large angle of incidence, while ensuring sufficient transparency of the screen 20 in the front direction. Therefore, the screen 20 can suppress screen haze caused by external light and improve its transparency. Furthermore, when projecting image light with the dimming layer 30 in a light-transmitting state, much of the ambient light incident at a large angle from the upper rear side of the screen 20 is absorbed by the dimming layer 30. Therefore, the contrast of the image can be improved compared to a screen without the dimming layer 30. In addition, the effects of suppressing image blurring and reducing reflections of images on the ceiling, as mentioned above, can still be expected, although they are reduced compared to when the screen is in a light-blocking state.

[0092] Based on the above, according to this embodiment, similar to the first embodiment, glare in the image can be suppressed, blurring of the image such as double images (reduction in resolution) can be suppressed and a clear image can be displayed, unwanted ambient light is not diffused and an image with high contrast and transparency can be displayed. Furthermore, according to this embodiment, the flatness of the screen surface can be improved, and image blurring such as double images can be suppressed. Furthermore, according to this embodiment, the dimming layer 30 can be appropriately selected and set to either a light-transmitting state or a light-blocking state depending on the usage environment, such as the image to be displayed or the screen 20, thereby improving convenience. Furthermore, according to this embodiment, reflections of images onto the ceiling or other surfaces behind the screen can be further suppressed.

[0093] (Transformed form) The present invention is not limited to the embodiments described above, and various modifications and changes are possible, all of which fall within the scope of the present invention. (1) In each embodiment, a hard coat layer for scratch prevention may be provided on the image source side (+Z side) and back side (-Z side) surfaces of the screens 10 and 20. The hard coat layer is formed, for example, by applying an ultraviolet-curable resin having a hard coat function (e.g., urethane acrylate) to the image source side and back side surfaces of the screen 10.

[0094] Furthermore, not limited to the hard coat layer, depending on the usage environment and purpose of the screens 10 and 20, one or more layers with appropriate functions such as anti-reflective function, ultraviolet absorption function, anti-fouling function, and anti-static function may be selected and provided on the image source side and back side surfaces of the screens 10 and 20. In addition, a touch panel layer or the like may be provided on the image source side of the light control layer 16. In particular, when an anti-reflective layer is provided on the surface of the screens 10 and 20 on the image source side, it reduces the reflection of image light on the surface of screen 10, increasing the amount of incident light on screens 10 and 20 and improving the brightness of the image. In addition, it prevents the image light reflected by the reflective layer 13 from being reflected at the interface with the air on the image source side and emitted to the back side, which would cause the image to appear to leak to the back. Furthermore, layers with various functions, such as a hard coat layer, may be provided on either the image source side or the back side surface of the screens 10 and 20.

[0095] (2) In the first embodiment, the screen 10 was shown to be transparent, but it is not limited to this and may be a reflective screen that is not transparent. Figure 9 shows the layer structure of the modified screen 50. Figure 9 shows a cross-section of the modified screen 50 that corresponds to the cross-section of the screen 10 in the embodiment shown in Figure 2. A magnified view of a portion of the cross-section passing through the center of the screen (geometric center of the screen), parallel to the vertical direction of the screen (Y direction), and perpendicular to the screen surface (parallel to the Z direction) is shown. The deformed screen 50 has, in order from the image source side along the thickness direction, an optical control layer 16, a bonding layer 17a, a first substrate layer 11, a first optical shaping layer 12, a reflective layer 53, and a second optical shaping layer 54. The reflective layer 53 is a layer that reflects light. The reflective layer 53 is formed on at least a portion of the first slope 121a. Figure 9 shows a configuration in which the reflective layer 53 is formed on the first slope 121a but not on the second slope 121b, but the configuration is not limited to this, and it may be formed on both the first slope 121a and the second slope 121b.

[0096] The reflective layer 53 is preferably formed on the first inclined surface 121a by depositing, sputtering, or transferring a metal foil such as aluminum, silver, or nickel. Furthermore, the reflective layer 53 can also be formed by applying and curing a silver-colored paint, an ultraviolet-curing resin or thermosetting resin containing silver-colored pigments or beads, or a paint containing crushed particles or fine flakes of metal vapor-deposited films such as silver or aluminum, or metal foil, using various coating methods such as spray coating, die coating, screen printing, or groove filling by wiping.

[0097] The second optical shaping layer 54 is provided on the back side (-Z side) of the reflective layer 53 and the first optical shaping layer 12, similar to the second optical shaping layer 14 in the embodiment, so as to cover them. This second optical shaping layer 54 has light-absorbing properties and does not transmit light. Since the second optical shaping layer 54 is in contact with the second inclined surface 121b, it can absorb ambient light such as sunlight or illumination light incident on the second inclined surface 121b from the image source side, thereby improving the contrast of the image. Furthermore, because the second optical shaping layer 54 has light-absorbing properties, even if a support plate (not shown) or the like, which is placed on the back side of the screen 50, has light-transmitting properties, it can suppress the reduction in image contrast caused by ambient light incident from the back side.

[0098] Such a second optically shaped layer 54 is preferably formed from a thermosetting resin or ultraviolet curing resin containing dark-colored pigments or dyes such as black, beads with light-absorbing properties, carbon black, etc., or from a dark-colored water-based paint or organic paint such as black. Furthermore, from the viewpoint of fully exhibiting light absorption and protective effects of the reflective layer 53, it is preferable that the second optical shape layer 54 has sufficient dimensions in the thickness direction of the screen 10, from the point t1 which is the vertex between the unit optical shapes 121 to its back surface.

[0099] The screen 50 is joined to a support plate (not shown) via a bonding layer (not shown). This support plate is preferably a plate-shaped member made of wood, glass, resin, etc., and is not light-transmitting. An interior wall or the like can also be used as the support plate.

[0100] Furthermore, the above examples are not limited to the above. The second optical shaping layer 54 may not have light-absorbing properties, and the support plate (not shown) placed on the back side of the screen may have light-absorbing properties (but not light-transmitting properties). Alternatively, a second substrate layer, which is a sheet-like resin layer and has light-absorbing properties, may be provided on the back side of the second optical shaping layer 54. The second optical shaping layer 54 and the second substrate layer may both have light-absorbing properties and not light-transmitting properties. Even with such a modified screen 50, a reflective screen 50 and image display device can be made that can display clear images and reduce glare (speckle) of the image.

[0101] (3) In each embodiment, the optical control layer 16 was described as selectively diffusing incident light in a cross section parallel to the vertical and thickness directions of the screen, depending on the incident angle in the vertical direction of the screen. However, the optical control layer 16 is not limited to this, and may be configured to selectively diffuse incident light in a cross section parallel to the arrangement direction and thickness direction of the unit optical shapes 121, depending on the incident angle in the arrangement direction of the unit optical shapes 121. As in each embodiment, when the unit optical shapes 121 are arranged concentrically around point C, the optical performance of the optical control layer 16 also has characteristics that are distributed concentrically. By adopting such a configuration, light can be diffused more effectively, and a sufficient viewing angle can be secured in areas where the viewing angle tends to decrease, such as the left and right edges of the upper part of the screen.

[0102] Furthermore, in each embodiment, the light control layer 16 is shown to have a constant specific angular range in which incident light is diffused and transmitted in a cross-section parallel to the vertical and thickness directions of the screen. However, it is not limited to this, and the specific angular range may change continuously or in steps along the vertical direction of the screen. By adopting such a configuration, light can be diffused more effectively in response to the incident angle of image light that changes in the vertical direction of the screen, and a good image can be displayed.

[0103] (4) In each embodiment, the light control layer 16 may be configured to transmit light incident from the back side (-Z side) without diffusion, regardless of the incident angle. That is, the light control layer 16 may be configured not to have a third incident angle range R3.

[0104] (5) In the first embodiment, the screen 10 may be provided with a colored layer on the image source side (+Z side) of the reflective layer 13, which acts as a light absorbing layer that transmits a portion of the incident light and absorbs a portion of it, and is colored with a dark coloring material such as black or gray to have a predetermined transmittance. By providing such a colored layer on the image source side of the reflective layer 13, the screen 10 can suppress the emission of light reflected at the interface with the air on the back side of the screen 10 towards the image source, which would result in a double image. In addition, by providing such a colored layer, the black brightness of the image can be reduced and ambient light from the image source can be absorbed, thereby improving the contrast of the image. Such a colored layer may be newly laminated, for example, on the image source side (+Z) of the light control layer 16, or, for example, the bonding layer 17a or the first substrate layer 11 may contain a coloring material and function as a colored layer.

[0105] Furthermore, in the first embodiment, the above-described colored layer may be provided on the back side (-Z side) of the reflective layer 13. By providing such a colored layer on the back side of the reflective layer 13, it is possible to suppress the emission of light reflected at the interface between the back side of the screen 10 and the air towards the image source, resulting in a double image, and a clear image can be displayed. In addition, by providing the colored layer on the back side of the reflective layer 13, the transparency of the screen when no image light is projected is reduced, but it is possible to absorb ambient light from the back side, resulting in a bright image with high contrast. Such a colored layer may be newly laminated on the back side of the second substrate layer 15, or for example, the second substrate layer 15 may contain a coloring material and function as a colored layer.

[0106] Furthermore, the above-mentioned light-absorbing layer (colored layer) is more effectively positioned on the side closest to the image source or the furthest back of the screen 10 in the first embodiment, that is, at the interface between the screen and the air. Furthermore, in the second embodiment, the colored layer may be provided instead of the light-adjusting layer 30.

[0107] (6) In each embodiment, the first bevel surface 121a and the second bevel surface 121b of the unit optical shape 121 may be, for example, a combination of a curved surface and a flat surface, or a folded surface. Furthermore, the unit optical shape 121 may be a polygonal shape formed by three or more faces. Furthermore, although the example shown illustrates the reflective layer 13 being formed on the first slope 121a and the second slope 121b, it is not limited to this configuration. For example, it may be formed on at least a portion of the first slope 121a. Furthermore, although the embodiment shows an example in which the first slope 121a and the second slope 121b have a fine and irregular uneven shape, the embodiment is not limited to this, and it is also possible to have a configuration in which only the first slope 121a has a fine and irregular uneven shape.

[0108] (7) In each embodiment, the image source LS was described as being located in the center of the screen 10, 20 in the left-right direction and below the screen, but it is not limited to this, and may be located above the screen 10, 20. In this case, the screen 10, 20 will be inverted in its vertical direction (Y direction). Alternatively, the image source LS may project image light onto the screens 10 and 20 from an oblique direction. In this case, point C, which is the Fresnel center of the circular Fresnel lens shape of the first optical shape layer 12, is positioned to match the position of the image source LS. This configuration allows the position of the image source LS to be freely set.

[0109] (8) In the first embodiment, the screen 10 may be configured without at least one of the first substrate layer 11 and the second substrate layer 15 if the first optical shape layer 12 and the second optical shape layer 14 have sufficient thickness and rigidity. Furthermore, the screens 10 and 20 may be configured such that the light control layer 16 is used as the base (substrate) for the first optical shape layer 12, and the first substrate layer 11, etc., is not included.

[0110] (9) In the second embodiment, the dimming layer 30 may be configured such that highly light-transmitting substrate layers are laminated on both sides thereof (the surface of the substrate 31A facing the image source and the surface of the substrate 31B facing the back) via a bonding layer or the like. A glass plate-shaped member is preferred as such a substrate layer. That is, this corresponds to a configuration in which the dimming layer 30 of the embodiment is placed inside laminated glass, and the back side of the second substrate layer 15 is connected via the bonding layer 17c Laminated It will be done. By shaping the dimming layer 30 in this manner, the liquid crystal material in the liquid crystal layer 36 falls in the direction of gravity at high temperatures, causing uneven distribution of the liquid crystal material and reducing the resulting unevenness in transmittance.

[0111] While each embodiment and its variations can be used in combination as appropriate, a detailed explanation is omitted. Furthermore, the present invention is not limited to the embodiments described above. [Explanation of symbols]

[0112] 1. Video display device 10,20 screens 11 First base layer 12 First optical shape layer 121 Unit Optical Shapes 121a First Slope 121b Second Slope 13 Reflective layer 14 Second optical shape layer 15,25 Second base layer 16. Light control layer 17a,17c Bonding layer 30 Dimming Layer LS video source

Claims

1. A reflective screen that displays an image by reflecting at least a portion of the image light projected from an image source, A first optical shape layer having a first surface into which image light is incident and a second surface intersecting it, and having a plurality of unit optical shapes arranged on the back side that are convex, A semi-transparent reflective layer is formed on at least a portion of the first surface of the unit optical shape, and has a fine and irregular uneven surface, which diffusely reflects a portion of the incident light and transmits a portion of it. A second optical shape layer is provided adjacent to the reflective layer on the back side of the reflective layer, has light transmittance, and is laminated to fill the valleys formed by adjacent unit optical shapes, A second substrate layer integrally laminated on the back side of the second optical shape layer, A light control layer located on the image source side of the reflective layer in the thickness direction of the reflective screen, which diffuses and transmits light incident from a specific angular range, and transmits light incident from outside the specific angular range without diffusion, A light-absorbing layer is provided on the back side of the aforementioned reflective layer, which absorbs a portion of the incident light and transmits a portion of it. Equipped with, It does not have a light-diffusing layer containing light-diffusing particles, The aforementioned light-absorbing layer is a dimming layer that can select between a state in which the absorption rate for light at a large angle of incidence is greater than the absorption rate for light at an angle of incidence of 0°, and a state in which the difference in light absorption rate depending on the angle of incidence is small. The angle α that the first surface of the unit optical shape makes with a surface parallel to the screen surface increases in one direction along the arrangement direction of the unit optical shape. The aforementioned specific angular range is a range in which, in a cross-section passing through the center point of the reflective screen and parallel to the arrangement direction of the unit optical shapes and the thickness direction of the reflective screen, the angle α is 25° or more and 55° or less on the side of the smaller angle α with respect to a straight line perpendicular to the surface of the optical control layer that is on the image source side. In the thickness direction of the reflective screen, the distance between the image source side surface of the first optical shape layer and the back side surface of the light control layer is 0.5 mm or less. In the thickness direction of the reflective screen, the distance from the image source side surface of the dimming layer to the back side surface of the second optical shape layer is greater than the distance from the back side surface of the light control layer to the image source side surface of the first optical shape layer. When a green screen is projected from the aforementioned image source onto the entire surface of the reflective screen, the speckle contrast Cs(G) is less than 0.

05. The dimming layer is provided on the back side of the second substrate layer via a bonding layer, The thickness of the second substrate layer is 3 to 8 mm. A reflective screen characterized by the following features.

2. In the reflective screen described in claim 1, The second optical shaped layer has a planar surface on its back side and has the same refractive index as the first optical shaped layer. A reflective screen characterized by the following features.

3. In the reflective screen described in claim 1, The first optical shaped layer and the second optical shaped layer are formed from the same UV-curable resin. A reflective screen characterized by the following features.

4. In the reflective screen according to any one of claims 1 to 3, The first optical shaping layer has a Fresnel lens shape on its back side, The aforementioned unit optical shapes are arc-shaped when viewed from a direction perpendicular to the screen surface, and are arranged concentrically around a point located outside the display area of ​​the reflective screen. A reflective screen characterized by the following features.

5. A reflective screen according to any one of claims 1 to 4, A video source that projects video light onto the aforementioned reflective screen, A video display device equipped with the following features.

6. In the video display device according to claim 5, The aforementioned specific angular range includes the incident angular range of the image light projected by the image source. A video display device characterized by the following.

Images