WO2023182411A1

WO2023182411A1 - Reflection-type screen, and image display device

Info

Publication number: WO2023182411A1
Application number: PCT/JP2023/011429
Authority: WO
Inventors: 直山口; 一紘笹原; 朱洋草原
Original assignee: 大日本印刷株式会社
Priority date: 2022-03-25
Filing date: 2023-03-23
Publication date: 2023-09-28
Also published as: JP2023142455A; JP7201115B1

Abstract

A screen 10 is a reflection-type screen and comprises: a lens layer 13 of which a surface side, in a thickness direction of the screen 10, upon which image light is projected is a first surface side and a reverse surface side is a second surface side, and having, on the second surface side, a Fresnel lens shape in which unit lenses 131 each including a lens surface 132 and a non-lens surface 133 and protruding to the second surface side are arranged; and a reflective layer 14 which is formed on the unit lenses 131 to reflect light. Each non-lens surface 133 has a first curved surface portion 134 in the shape of a curved surface on an end portion on the first surface side, wherein the first curved surface portion 134 is positioned in a region of the non-lens surface 133 adjacent to the lens surface 132 of the adjacent unit lens 131, and a proportion occupied by a dimension of the lens surface 132 in a direction in which the unit lenses 131 are arranged, relative to an arrangement pitch of the unit lenses 131, is 60% to 95% inclusive.

Description

Reflective screen, video display device

The present invention relates to a reflective screen and an image display device.

Conventionally, various developments have been made to display good images in reflective screens and video display devices equipped with the same (for example, Patent Document 1, etc.).
Furthermore, in recent years, short-focus video sources have been widely used in video display devices equipped with reflective screens. Such a short focus type image source can project image light at a large angle of incidence from a short distance to a reflective screen, and can reduce the size of an image display device in the depth direction.

JP2008-076522A

However, when such an image source is used, the angle of incidence of the image light on the reflective screen is large, and a portion of the image light is reflected on the surface of the reflective screen, causing the image to be reflected on the ceiling, etc. This may occur. Such reflection of the image on the ceiling or the like is particularly obtrusive when viewing the image in a dark room, for example, and hinders comfortable viewing of the image.

An object of the present invention is to provide a reflective screen and an image display device that can suppress the reflection of images on the ceiling or the like and display good images.

The present invention solves the above problems by the following solving means. Note that, in order to facilitate understanding, the description will be given with reference numerals corresponding to the embodiments of the present invention, but the present invention is not limited thereto.
The first invention is a reflective screen that reflects and displays image light projected from an image source, and in the thickness direction of the reflective screen, the surface side on which the image light is projected is the first surface side. , a Fresnel lens shape in which unit lenses (131) having a lens surface (132) and a non-lens surface (133) and convex on the second surface side are arranged with the back side as the second surface side. A lens layer (13) formed on the second surface side, and a reflective layer (14) formed on the unit lens to reflect light, and the non-lens surface has a curved surface at the end on the first surface side. The first curved surface portion (134) is located on the non-lens surface in a region adjacent to the lens surface of the adjacent unit lens, and the first curved surface portion is arranged at an arrangement pitch of the unit lenses. On the other hand, the reflective screen (10) is characterized in that the ratio of the dimensions of the lens surface in the arrangement direction of the unit lenses is 60% or more and 95% or less.
A second invention is the reflective screen according to the first invention, in which the screen is divided into three in the vertical direction and in the horizontal direction of the screen in a state of use to form a total of nine areas, and the nine areas are divided into three areas. This is a reflective screen (10) characterized in that the standard deviation σ with respect to the speckle value S of is 1.38 or less.
A third invention is the reflective screen according to the first invention or the second invention, wherein the non-lens surface (133) has a curved second curved surface portion (135) at an end on the second surface side. The reflective screen (10) is characterized in that the radius of curvature of the first curved surface portion (134) is larger than the radius of curvature of the second curved surface portion.
A fourth invention is the reflective screen according to the third invention, wherein the non-lens surface (133) is a planar area between the first curved surface portion (134) and the second curved surface portion (135). (136), and the angle (γ) corresponding to the apex angle of the unit lens and at which the extension direction of the lens surface and the extension direction of the planar area intersect is an acute angle. This is a reflective screen (10).
A fifth invention is the reflective screen according to the first invention or the second invention, in which in a cross section parallel to the arrangement direction of the unit lenses (131) and the thickness direction of the reflective screen, the unit lenses Corresponding to the apex angle, a point (t1) closest to the first surface and a point (t2) closest to the second surface in the extending direction of the lens surface (132) and the non-lens surface (133) The reflective screen (10) is characterized in that the angle (γ) at which the tangential direction intersects with the tangential direction at a point (t3) that is equidistant from the reflection screen (10) is an acute angle.
A sixth invention is a reflective screen according to any one of the first to fifth inventions, in which the lens layer (13) is arranged such that the unit lens (131) is located outside the display area of the reflective screen. This is a reflective screen (10) characterized by having a circular Fresnel lens shape arranged concentrically with one point (C) as the center.
A seventh invention is a reflective screen according to any one of the first to sixth inventions, in which a colored layer ( 122).
An eighth invention is a reflective screen according to any one of the first invention to the seventh invention, in which a light diffusion layer ( 121) is a reflective screen (10).
A ninth invention is a video display device comprising the reflective screen (10) according to any one of the first to eighth inventions, and a video source (LS) that projects video light onto the reflective screen. (1).

According to the present invention, it is possible to provide a reflective screen and an image display device that can suppress the reflection of images on the ceiling or the like and display good images.

1 is a diagram showing a video display device 1 according to an embodiment. It is a figure showing the layer composition of screen 10 of an embodiment. It is a figure explaining the lens layer 13 and the unit lens 131 of embodiment. FIG. 3 is a diagram illustrating the unit lens 131 in more detail. It is a figure which shows an example of the image light and external light which enter the unit lens 131 of embodiment. FIG. 7 is a diagram schematically showing the cross-sectional shape of the unit lens at the center of the screen in Measurement Examples 1 to 8. FIG. 2 is a diagram showing each area of the screen when calculating the standard deviation σ of speckle values. FIG. 7 is a diagram illustrating a table summarizing the evaluation results of image reflection on the screen ceiling and image glare in Measurement Examples 1 to 8. 7 is a diagram illustrating an angle γ corresponding to the apex angle of a unit lens 131. FIG.

Embodiments of the present invention will be described below with reference to the drawings and the like. Note that each figure shown below, including FIG. 1, is a schematic diagram, and the size and shape of each part are appropriately exaggerated for easy understanding.
In this specification, terms that specify shapes or geometrical conditions, such as terms such as parallel and orthogonal, do not have strict meanings, but also mean that they have similar optical functions and can be considered parallel or orthogonal. This also includes states with errors.
In addition, the numerical values such as dimensions and material names of each member described in this specification are examples of embodiments, and are not limited to these, and may be appropriately selected and used.

In addition, although words such as plate, sheet, etc. are used in this specification, these are generally used in the order of thickness, such as plate, sheet, and film. This is also used in the book. However, since there is no technical meaning in these different uses, these words can be replaced as appropriate.
Furthermore, the term "screen surface" refers to the plane of the reflective screen when viewed as a whole, and the screen of the reflective screen is parallel to this screen surface.

(Embodiment)
FIG. 1 is a diagram showing a video display device 1 of this embodiment. FIG. 1(a) is a perspective view of the video display device 1, and FIG. 1(b) is a diagram of the video display device 1 viewed from the side (+X side described later).
The video display device 1 includes a screen 10, a video source LS, and the like. The screen 10 of this embodiment is a reflective screen that reflects the image light L projected from the image source LS and displays an image on the screen. Details of this screen 10 will be described later.

Here, in order to facilitate understanding, in each of the figures shown below, including FIG. 1, an XYZ orthogonal coordinate system is provided as appropriate. In this coordinate system, in the video display device 1, the vertical direction is the Y direction, the horizontal direction is the X direction, and the depth direction is the Z direction. When the screen 10 is in use, the X direction is parallel to the horizontal direction of the screen, the Y direction is parallel to the vertical direction of the screen, and the Z direction is parallel to the thickness direction of the screen 10. 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.

When the screen 10 of this embodiment is in use, the screen (display area) of the screen is parallel to the XY plane, the up and down direction (Y direction) of the screen is vertical, and the left and right direction (X direction) of the screen is horizontal. are arranged so that The screen 10 has a second surface 10b on the back side (-Z side) and a first surface 10a on the viewer side (+Z side) in the thickness direction.
When viewed from an observer O located in the front direction of the screen 10, the direction toward the right side in the horizontal direction of the screen is the +X direction, the direction toward the upper side in the vertical direction of the screen is the +Y direction, and the second surface side (back surface side) in the thickness direction of the screen 10. The direction from the side (side, back side) to the first side (observer side, image source side) is defined as +Z direction.
In the following explanation, unless otherwise specified, the screen vertical direction (vertical direction), screen horizontal direction (horizontal direction), and thickness direction in the usage state of this screen 10 are referred to as the screen vertical direction, screen horizontal direction, and thickness direction. (depth direction).

The image source LS is an image projection device that projects the image light L onto the screen 10, and is, for example, a short focus projector. The video source LS of this embodiment uses a laser light source as a light source, for example.
This video source LS is located outside the display area of the screen 10 when the screen (display area) of the screen 10 is viewed from the front direction (normal direction of the screen surface) when the video display device 1 is in use, It is located at the center of the screen 10 in the horizontal direction (X direction) and on the lower side (-Y side) of the screen 10 in the vertical direction.

The image source LS can project image light L obliquely from a position that is much closer to the surface of the screen 10 in the depth direction (Z direction) of the image display device 1 than a conventional general-purpose projector. Therefore, compared to a conventional general-purpose projector, the image source LS has a shorter projection distance of the image light L to the screen 10, and a larger incident angle at which the projected image light L enters the screen 10.

The screen 10 is a reflective screen that reflects the image light L projected by the image source LS toward the observer O and displays an image.
The screen (display area) of the screen 10 has a substantially rectangular shape in which the long side direction is the left-right direction (X direction) of the screen when viewed from the observer O side when in use.
The screen 10 has a large screen size of about 40 to 100 inches diagonally, and the screen has an aspect ratio of 16:9. Note that the screen size is not limited to this, for example, the screen size may be less than 40 inches, and the size and shape can be selected as appropriate depending on the purpose of use, environment of use, etc.
In this embodiment, an example in which the screen size of the screen is 80 inches will be described.

FIG. 2 is a diagram showing the layer structure of the screen 10 of this embodiment. In Fig. 2, the line passes through point A (see Fig. 1), which is the screen center of the screen 10 (the geometric center of the screen), is parallel to the screen vertical direction (Y direction), and is orthogonal to the screen surface (in the Z direction). This is an enlarged view of a part of the cross-section that is parallel to the surface.
As shown in FIG. 2, the screen 10 includes, in order from the first surface side (+Z side), a surface layer 11, a base material layer 12, a lens layer 13, a reflective layer 14, and a back surface protective layer 15, which are integrally formed. are laminated on.

The surface layer 11 is a layer provided on the first surface side (+Z side) of the base material layer 12. The surface layer 11 of this embodiment forms the outermost surface (first surface 10a) of the screen 10 on the viewer side.
The surface layer 11 of this embodiment has a hard coat function and an anti-glare function, and the surface on the first surface side of the base layer 12 is made of an ultraviolet curable resin (for example, urethane acrylate) having a hard coat function. An ionizing radiation-curable resin such as the above is applied to a film thickness of about 10 to 100 μm, and a fine uneven shape (matte shape) is transferred to the resin film surface and cured, resulting in fine unevenness on the surface. The shape is formed. Therefore, the surface of the surface layer 11 facing the viewer has a rough surface.

The surface layer 11 is not limited to the above examples, and may be provided with one or more necessary functions, such as an antireflection function, an antiglare function, a hard coat function, an ultraviolet absorption function, an antifouling function, and an antistatic function. It's okay.
Further, the surface layer 11 may be bonded to the base material layer 12 with an adhesive (not shown), or may be directly attached to the surface of the base material layer 12 on the side opposite to the lens layer 13 (first surface side). may be formed.

The base material layer 12 is a layer having optical transparency, and is a sheet-like member that serves as a base material for forming the lens layer 13 . The surface layer 11 is integrally formed on the first surface side (+Z side) of the base material layer 12, and the lens layer 13 is integrally formed on the second surface side (−Z side).
The base layer 12 has a light diffusion layer 121 containing a diffusing agent and a colored layer 122 containing a coloring material such as a pigment or dye. The base material layer 12 of this embodiment is formed by integrally laminating the light diffusion layer 121 and the colored layer 122 by co-extrusion molding. Note that the present invention is not limited to this, and these layers may be integrally laminated via a bonding layer (not shown) made of a light-transmitting adhesive or adhesive.
In this embodiment, as shown in FIG. 2, in the base material layer 12, the light diffusion layer 121 is located on the first surface side (+Z side), and the colored layer 122 is located on the second surface side (-Z side). ing.

The light diffusion layer 121 is a layer that has a base material made of a light-transmitting resin and contains a diffusing agent that diffuses light. The light diffusion layer 121 has the function of widening the viewing angle and improving the in-plane uniformity of brightness.
Examples of the resin that serves as the base material of the light diffusion layer 121 include PET (polyethylene terephthalate) resin, PC (polycarbonate) resin, MS (methyl methacrylate styrene) resin, MBS (methyl methacrylate butadiene styrene) resin, and TAC ( Triacetyl cellulose) resin, PEN (polyethylene naphthalate) resin, acrylic resin, etc. are preferably used.

As the diffusing agent contained in the light diffusing layer 121, particles made of resin such as acrylic resin, epoxy resin, silicone resin, or inorganic particles are preferably used. Note that the diffusing agent may be a combination of an inorganic diffusing agent and an organic diffusing agent. The diffusing agent is preferably approximately spherical and has an average particle size of approximately 1 to 50 μm, more preferably 5 to 30 μm.
The thickness of the light diffusion layer 121 is preferably about 100 to 2000 μm, although it depends on the screen size of the screen 10 and the like. It is desirable that the light diffusion layer 121 has a haze value in the range of 1 to 50%.

In a reflective screen like this embodiment, in order to improve the front brightness, it is conceivable to reduce the content of the diffusing agent in the light diffusing layer. However, if the content of the diffusing agent is reduced when the reflective layer and the light diffusing layer are provided close to each other in the thickness direction of the screen, the position of the diffusing agent within the light diffusing layer becomes localized. , glare (scintillation) may occur in the image, making it impossible to display a good image.
Therefore, in the screen 10 of the present embodiment, a light diffusion layer 121 and a colored layer 122 are arranged in order from the first surface side (+Z side) in the base layer 12, and the light diffusion layer 121 and the reflection layer in the thickness direction of the screen 10 are arranged in order from the first surface side (+Z side). It is separated from the layer 14 by a predetermined distance. As a result, the screen 10 of the present embodiment improves front brightness and suppresses the occurrence of glare in images even when the position of the diffusing agent in the light diffusing layer is localized as described above. can do.

In the screen 10, it is desirable that the shortest distance between the light diffusion layer 121 and the reflective layer 14 in the thickness direction of the screen is 450 μm or more and 1370 μm or less. This shortest distance refers to the distance from the point closest to the first surface (+Z side) of the reflective layer 14 to the surface of the light diffusion layer 121 on the second surface side in the normal direction (thickness direction) of the screen surface. . The point closest to the first surface of the reflective layer 14 corresponds to a point t1 shown in FIG. 3(b), which will be described later, and is the bottom of the valley between the unit lenses 131 on which the reflective layer 14 is formed.

If the shortest distance between the light diffusing layer 121 and the reflective layer 14 in the thickness direction is less than 450 μm, the light diffusing layer 121 and the reflective layer 14 will be too close to each other, causing glare in the image (also referred to as scintillation, speckles, etc.) This is undesirable because the suppressing effect of Moreover, if the shortest distance is larger than 1370 μm, the thickness of the screen becomes thick and the weight of the screen increases too much, which is not desirable. Therefore, the shortest distance between the light diffusing layer 121 and the reflective layer 14 is preferably within the above range.

The colored layer 122 is a layer colored with a dark coloring agent such as black so as to have a predetermined light transmittance. The colored layer 122 has the function of absorbing unnecessary external light such as illumination light that enters the screen 10 and reducing the black luminance of the displayed image to improve the contrast of the image.
As the coloring agent for the colored layer 122, dark color dyes and pigments such as gray and black, and metal salts such as carbon black, graphite, and black iron oxide are suitably used.
As the resin serving as the base material of the colored layer 122, PET resin, PC resin, MS resin, MBS resin, TAC resin, PEN resin, acrylic resin, etc. can be used.
The thickness of the colored layer 122 is preferably about 430 to 1350 μm, although it depends on the screen size of the screen 10 and the like.

FIG. 3 is a diagram illustrating the lens layer 13 and unit lens 131 of this embodiment.
FIG. 3(a) shows the lens layer 13 observed from the front direction of the second surface side (-Z side), and the reflective layer 14 and back protective layer 15 are omitted for easy understanding. It is shown as follows. FIG. 3(b) shows a further enlarged part of the cross section of the screen 10 shown in FIG. 2, and only the lens layer 13 and the reflective layer 14 are shown for easy understanding.

The lens layer 13 is a layer provided on the second surface side (-Z side) of the base material layer 12 and has a light transmitting property. As shown in FIG. 3(a) etc., the lens layer 13 has a circular Fresnel lens shape in which a plurality of unit lenses 131 are arranged concentrically around a point C on its second surface side. . Therefore, when the lens layer 13 is viewed from the front direction on the second surface side (-Z side), it is observed that the unit lenses 131 having a partially perfect circular shape (arc shape) are arranged.

This point C is outside the screen of the screen 10 (outside the display area), and is located at the center of the screen 10 in the horizontal direction and below the screen 10, similarly to the video source LS. Therefore, as shown in FIG. 3A, when viewed from the normal direction of the screen surface of the screen 10, points A and C are located on a straight line parallel to the vertical direction of the screen.
In this embodiment, the lens layer 13 will be described using an example in which the second surface side (-Z side) has a circular Fresnel lens shape. It is also possible to have a linear Fresnel lens shape arranged in the vertical direction of the screen.

As shown in FIGS. 2 and 3(b), the unit lens 131 has a lens surface 132 and a non-lens surface in a cross section passing through point A and parallel to the arrangement direction of the unit lenses 131 and parallel to the thickness direction of the screen 10. 133. In the unit lens 131 of this embodiment, the non-lens surface is located on the lower side (−Y side) of the lens surface 132 in the vertical direction of the screen in the cross section shown in FIG. 2 or FIG. 3(b).
The lens surface 132 is linear in the cross section shown in FIG. 2 or FIG. 3(b), and the end on the side far from the image source LS (upper side in the vertical direction of the screen) in the arrangement direction of the unit lenses 131 is connected to the image source LS. It is inclined so that it is closer to the first surface (+Z side) than the edge on the near side (lower side in the vertical direction of the screen). This lens surface 132 is a surface that exhibits a Fresnel lens-shaped lens effect formed in the lens layer 13.

As shown in FIG. 3(b), the non-lens surface 133 is a portion located between adjacent lens surfaces 132 in the arrangement direction of the unit lenses 131, and connects the adjacent lens surfaces 132. This non-lens surface 133 is smoothly continuous with the adjacent lens surface 132.
The non-lens surface 133 has a point t2 that is the apex of a shape that is convex toward the second surface side (-Z side) and a point t1 that is the apex of a shape that is convex toward the first surface side (+Z side). ing. This point t1 is the bottom of the valley between adjacent unit lenses 131 when point t2 is the apex of the unit lens 131, and is located in a curved area corresponding to the valley between the unit lenses 131. There is.

The non-lens surface 133 has a curved shape in which at least a region including this point t1 is convex toward the first surface side, and this region is particularly referred to as a first curved surface portion 134. Further, in this embodiment, a region of the non-lens surface 133 including the point t2 has a curved surface shape convex toward the second surface side, and this region is referred to as a second curved surface portion 135. Further, in this embodiment, as shown in FIG. 3(b), the non-lens surface 133 has a substantially planar region 136 between the first curved surface portion 134 and the second curved surface portion 135, The first curved surface portion 134 and the second curved surface portion 135 are connected via this planar region 136.
Note that the unit lens 131 is not limited to the above-described example, and the unit lens 131 may have a form in which the first curved surface portion 134 and the second curved surface portion 135 are directly continuous without interposing the planar region 136. Furthermore, the area including the point t2 may not include the second curved surface portion 135, but may be configured to include a plane that is an extension of the lens surface 132 and a planar area 136.

In this embodiment, the first curved surface portion 134 and the second curved surface portion 135 have a substantially arcuate cross-sectional shape as shown in FIG. 3(b), and the radius of curvature of the first curved surface portion 134 is is larger than the radius of curvature.
Note that the first curved surface portion 134 and the second curved surface portion 135 of the non-lens surface 133 may have, for example, a partial shape of an ellipse or other curved shape in the cross section shown in FIG. 3(b). Good too.

As shown in FIG. 3(b), the arrangement pitch of the unit lenses 131 is P, and the lens height of the unit lenses 131 (dimension from point t2 to point t1 in the thickness direction of the screen 10) is h. .
In this embodiment, the angle that the lens surface 132 makes with a surface parallel to the screen surface is α, and the angle that the planar region 136 of the non-lens surface 133 makes with a surface parallel to the screen surface is β. Note that if the non-lens surface 133 does not have a planar region 136, the tangent at a point on the non-lens surface 133 that is equidistant from points t1 and t2 and a surface parallel to the screen surface are Let the angle formed be angle β. This angle β is larger than the angle α.

To facilitate understanding, in FIG. 2 and the like, the arrangement pitch P, angle α, etc. of the unit lenses 131 are shown to be constant in the arrangement direction of the unit lenses 131. However, in the unit lenses 131 of this embodiment, although the arrangement pitch P is actually constant, the angle α gradually increases as the distance from point C in the arrangement direction of the unit lenses 131 increases, and accordingly the lens height increases. h has also increased.

In this embodiment, the arrangement pitch P is preferably 50 to 200 μm. Further, the angle α of the lens surface 132 is formed in a range of 0.5 to 35°.
Note that the arrangement pitch P is not limited to this, and may have a form that gradually changes along the arrangement direction of the unit lenses 131, and may vary depending on the size of a pixel of the image source LS that projects the image light L or the image source. It can be changed as appropriate depending on the projection angle of the LS (the angle of incidence of the image light onto the screen surface of the screen 10), the screen size of the screen 10, the refractive index of each layer, etc.

The lens layer 13 is made of an ultraviolet curable resin such as urethane acrylate or epoxy acrylate on the second surface side (-Z side) of the base layer 12 (in this embodiment, the surface on the back side of the colored layer 122). , which are integrally formed by ultraviolet molding. In addition, the lens layer 13 may be formed of other ionizing radiation curable resins such as electron beam curable resins, or may be formed of thermoplastic resins.
Further, the material and molding method for forming the lens layer 13 can be appropriately selected depending on the shape and material of the Fresnel lens on the second surface side of the lens layer 13.

The reflective layer 14 is a layer that has the function of reflecting incident light. The reflective layer 14 is formed on at least a portion of the lens surface 132. The reflective layer 14 of this embodiment is formed on the lens surface 132 and the non-lens surface 133, as shown in FIG. 2 and FIG. 3(b).
The reflective layer 14 is made of a metal with high light reflectivity, such as aluminum, silver, nickel, chromium, etc. The reflective layer 14 of this embodiment is formed by vapor depositing aluminum, and the thickness of the reflective layer 14 is about 800 Å.

The reflective layer 14 is not limited to this, and may be formed by, for example, sputtering a highly reflective metal, transferring a metal foil, or applying a paint containing a metal thin film or the like. For example, it may be formed by depositing a dielectric multilayer film or a dielectric single layer film.
The reflective layer 14 may be formed by applying a white or silver paint, an ultraviolet curable resin or a thermosetting resin containing white or silver pigments, beads, etc. by spray coating, die coating, screen printing, or wiping. It may be formed by coating and curing by various coating methods such as groove filling.

The back surface protective layer 15 is a layer provided on the second surface side (-Z side) of the reflective layer 14 and protects the reflective layer 14 and the back surface side (back side) of the screen 10.
As shown in FIG. 2, the back surface protective layer 15 of this embodiment covers the reflective layer 14, fills in the irregularities caused by the unit lenses 131, and flattens the second surface 10b of the screen 10.
In addition, the back protective layer 15 has a light-absorbing function, which means that it absorbs unnecessary external light such as sunlight and illumination light that enters the screen 10 from the second surface side (-Z side), thereby improving the image quality. This is preferable from the viewpoint of improving the contrast.

The back protective layer 15 of this embodiment has a light-absorbing function, and is made of a dark-colored paint such as black, a dark-colored pigment or dye such as black, and beads having a light-absorbing function. The reflective layer 14 is formed by applying a resin containing a material to the second surface side of the reflective layer 14 and curing the resin. Preferred examples of such resins include thermosetting resins such as epoxy resins and urethane resins, thermoplastic resins such as acrylic resins, and ultraviolet curable resins such as urethane acrylates and epoxy acrylates.
Further, from the viewpoint of protecting the reflective layer 14 and the lens layer 13, the back surface protective layer 15 may have an ultraviolet absorbing function, a hard coat function, and the like.

Here, the shape of the unit lens 131 of this embodiment will be explained in more detail.
FIG. 4 is a diagram illustrating the unit lens 131 in more detail. FIG. 4(a) shows a cross section of the unit lens 131 of this embodiment, and FIG. 4(b) shows a cross section of a conventional unit lens 531. In FIGS. 4A and 4B, for ease of understanding, only the lens layer 13 of this embodiment and the conventional lens layer 53 are shown, respectively, and for each lens layer, the arrangement direction of the unit lenses and the screen A part of the cross section parallel to the thickness direction is shown enlarged.
The unit lens 131 of this embodiment shown in FIG. 4(a) and the conventional unit lens 531 shown in FIG. 4(b) are located on a straight line that passes through point A and is parallel to the vertical direction of the screen. is on the upper side of the screen in the vertical direction and the distance from point C is the same.

A conventional unit lens 531 has a lens surface 532 and a non-lens surface 533. Further, the conventional unit lens 531 is similar to the unit lens 131 of the present embodiment except that it does not include the first curved surface portion 134 and the second curved surface portion 135 and the non-lens surface 533 is planar. The pitch P, the angle α, and the incident angle of the image light onto the lens surface 532 are also the same.
As shown in FIG. 4B, the image light La projected from the image source LS is incident on the lens surface 532 of the conventional unit lens 531 at a predetermined incident angle. At this time, the lens surface 532 includes a reflective region 532A, which is a region on which the image light La is incident, and a non-reflective region 532B, which is a region on which the image light La is not incident.
The ratio of the size of the reflective area 532A in the arrangement direction of the unit lenses 531 to the arrangement pitch P is Wa/P.

In contrast, in the unit lens 131 of this embodiment, the second curved surface portion 135 of the non-lens surface 133 is formed in a region corresponding to the non-reflection region of the lens surface 132. As a result, the reflective area occupied by the lens surface 132 is secured to be the same as that of the conventional unit lens 531, while the non-reflective area of the lens surface 132 is made much smaller than that of the conventional unit lens 531. Therefore, in this embodiment, the ratio W1/P of the dimension of the lens surface 132 in the arrangement direction of the unit lenses 131 to the arrangement pitch P (hereinafter referred to as the ratio of the lens surface 132 to the arrangement pitch) is The ratio Wa/P of the reflective area 532A of the unit lens 531 to the arrangement pitch is equal or approximately equal.
Further, the image light La is incident on this unit lens 131 at a predetermined incident angle, similarly to the unit lens 531 of the comparative example.
Therefore, in the unit lens 131 of this embodiment, the amount of reflected light of the image light La is equivalent to the amount of reflected light of the image light La in the conventional unit lens 531.

Next, as shown in FIG. 4B, in the conventional unit lens 531, a part of the image light (image light Lb) is incident on a point t1 that is convex toward the first surface side (+Z side), The light is reflected by the reflective layer 14 and exits upward on the first surface side of the screen. The amount of such image light Lb is small. Therefore, even if the image light Lb reaches the ceiling or the like, it is not possible to reduce the reflection of the image due to the image light reflected on the viewer's surface of the screen.
On the other hand, in the unit lens 131 of this embodiment, as shown in FIG. The light is diffusely reflected by the curved surface shape and the reflective layer 14. Then, some of the image lights Lc and Ld are emitted upward on the first surface side of the screen 10, and some of the image light Le is totally reflected at the interface on the first surface side of the screen 10 and passes through the inside of the screen 10. It propagates upward and eventually attenuates.

Since the image lights Lc and Ld emitted upward from the screen 10 are diffusely reflected, the image reflected on the surface (first surface 10a) of the screen 10 and reflected on the ceiling etc. is blurred and unclear. It has the effect of becoming Thereby, the screen 10 of this embodiment can suppress the reflection of images on the ceiling or the like. Further, a small amount of the diffusely reflected image light Lc reaches the observer O, which has the effect of reducing glare in the image.

Note that the ratio W1/P of the dimension of the lens surface 132 to the arrangement pitch P in the arrangement direction of the unit lenses 131 is preferably 60% or more and 95% or less.
If this ratio W1/P is less than 60%, the lens surface 132 becomes smaller with respect to the arrangement pitch P, which reduces the reflective area and lowers the front brightness of the image, which is not preferable. Further, if the ratio W1/P is greater than 95%, the first curved surface portion 134 becomes too small, and the effect of suppressing the reflection of the image on the ceiling etc. as described above cannot be obtained sufficiently. Therefore, the ratio W1/P is preferably within the above range.

In this embodiment, since the arrangement pitch P is constant, this ratio W1/P gradually becomes smaller as it moves away from the point C (image source LS) along the arrangement direction of the unit lenses 131 within the above-mentioned preferable range. ing.
In the arrangement direction of the unit lenses 131, in a region close to point C (in this embodiment, for example, the lower side in the vertical direction of the screen), the angle α is small and the lens height h is small, so that the curvature of the first curved surface portion 134 is small. The radius becomes smaller and the ratio W1/P becomes larger. On the other hand, in the arrangement direction of the unit lenses 131, in a region far from point C (in this embodiment, for example, the upper side in the vertical direction of the screen), the angle α is large and the lens height h is also large, so that the first curved surface portion 134 The radius of curvature becomes larger and the ratio W1/P becomes smaller.
Note that the present invention is not limited to this, and the ratio W1/P may gradually decrease within the above-mentioned preferable range as it moves away from the point C (image source LS) along the arrangement direction of the unit lenses 131. , may be constant in the arrangement direction of the unit lenses 131.

Furthermore, since the non-lens surface 133 has the first curved surface portion 134, in addition to the effect of suppressing the reflection of the image on the ceiling etc., the glare (also referred to as scintillation, speckle, etc.) of the displayed image is reduced. It was found that this effect can be obtained.
Regarding the glare in the image, the screen 10 is divided into 9 regions, each divided into 3 in the vertical direction and in the horizontal direction of the screen, and the speckle value at the geometric center of each region is ( Speckle contrast) was measured and defined by the standard deviation σ of the speckle values of the nine regions. From the viewpoint of reducing glare in images, it is preferable that the standard deviation σ of the speckle values in the nine regions is smaller, and particularly preferably less than 1.38.

FIG. 9 is a diagram illustrating the angle γ corresponding to the apex angle of the unit lens 131. Similar to FIG. 2 and the like, FIG. 9 is a cross section that passes through the thickness direction of the screen 10 and point A and is parallel to the arrangement direction of the unit lenses 131, and shows only a part of the unit lenses 131 in an enlarged manner. Further, FIG. 9(a) shows a unit lens 131 in which the non-lens surface 133 has a planar region 136, and FIG. 9(b) shows a unit lens 131 in which the non-lens surface 133 does not have a planar region 136. It shows.

In the cross section shown in FIG. 9A, the angle γ, which corresponds to the apex angle of the unit lens 131 and is formed by the extending direction of the lens surface 132 and the extending direction of the planar region 136 of the non-lens surface 133, is an acute angle. That is, it is preferable that 0°<γ<90°.
When the angle γ is 90° or more, the ratio of the dimension of the non-lens surface 133 to the arrangement pitch P in the arrangement direction of the unit lenses 131 becomes large, and the ratio W1/P becomes small. Therefore, the area of the lens surface 132 that reflects the image light (the area of the reflection region) is reduced. Furthermore, the amount of image light incident on the non-lens surface 133 increases. For these reasons, the amount of image light reflected toward the viewer decreases, resulting in a dark image.

In addition, if the angle γ is 90° or more, as described above, the image light incident on the non-lens surface 133 and reflected by the reflective layer 14 becomes stray light, which reduces the contrast and clarity of the image displayed on the screen. This results in a decrease in
Furthermore, if the angle γ is 90° or more, unnecessary external light or the like enters the non-lens surface 133 and is likely to be reflected toward the viewer, reducing the contrast of the image.
From the above, it is preferable that the angle γ is an acute angle (0°<γ<90°).

As shown in FIG. 9B, in the case of a unit lens 131 in which the non-lens surface 133 does not have a planar region 136, the points t1 and 1 on the first curved surface portion 134 on the non-lens surface 133 Let γ be the angle that a tangent at a point equidistant from point t2 on the two-curved surface portion 135 (point t3 shown in FIG. 9(b)) makes with the extension direction of the lens surface 132.

FIG. 5 is a diagram showing an example of image light and external light incident on the screen 10 of this embodiment. The cross section of the screen 10 shown in FIG. 5 is similar to the cross section of the screen 10 shown in FIG. 2 described above. In FIG. 5, for ease of understanding, it is assumed that the refractive index between the surface layer 11 and the base material layer 12 and between the base material layer 12 and the lens layer 13 are equal, and the refractive index for image light and external light is The light diffusion effect of the diffusion layer 121 and the like are omitted.
As shown in FIG. 5, most of the image light L1 projected from the image source LS is incident on the screen 10 like the image light L2, and the surface layer 11 and the base material layer 12 (light diffusion layer 121, The light passes through the colored layer 122) and heads toward the lens layer 13.

However, a part (image light L3) of the image light L1 projected from the image source LS is reflected on the surface of the screen 10 and heads upward on the first surface side of the screen 10, causing the image to be projected onto the ceiling or the like. This may cause reflections. However, fine irregularities are formed on the surface of the surface layer 11 in this embodiment, so that the image light L3 reflected toward the ceiling etc. is diffused, and the reflection of the image on the ceiling etc. is reduced.

Most of the image light L2 incident on the screen enters the lens surface 132 of the unit lens 131, is reflected by the reflective layer 14, and exits from the screen 10 toward the first surface side, approximately in the front direction, and is observed. It reaches Person O. Thereby, the screen 10 can display bright images.
At this time, since the screen 10 has a sufficient distance between the reflective layer 14 and the light diffusion layer 121 in the thickness direction, the brightness of the image light can be made uniform without significantly reducing the front brightness. , can suppress glare in images.

Note that since the image light L1 is projected from below the screen 10 and the angle β is larger than the incident angle of the image light L1 at each point in the vertical direction of the screen 10, the image light L1 is projected from the bottom of the non-lens surface 133. The light does not directly enter a region other than the first curved surface portion 134 (for example, the second curved surface portion 135, etc.).
Furthermore, since the first curved surface portion 134 of the non-lens surface 133 does not largely block the image light L2 incident on the lens surface 132 in the unit lens 131, the front brightness of the image is maintained, and the screen 10 displays a bright image. can.

Further, the first curved surface portion 134 and the reflective layer 14 diffusely reflect a portion of the image light L2 (image light L4) toward the upper side of the screen, and a portion of the image light L2 is emitted upward on the first surface side of the screen 10. Thereby, the reflection of the image on the ceiling or the like can be made unclear, and the reflection of the image can be suppressed. Furthermore, as shown in the image light Lc in FIG. 4A, a portion of the image light L4 is diffused and a portion of the image light L4 is directed toward the viewer, thereby reducing glare in the image.

On the other hand, unnecessary external lights G1 and G2 such as illumination light mainly enter the screen 10 from above, as shown in FIG. Then, a portion (not shown) of the external lights G1 and G2 is reflected on the surface of the screen and travels below the screen 10. Moreover, most of the external lights G1 and G2 enter the screen 10, pass through the surface layer 11 and the base layer 12, and enter the unit lenses 131 of the lens layer 13.
Then, the external light G1 enters the non-lens surface 133, is reflected by the reflective layer 14, is further reflected by the lens surface 132, etc., and heads upward toward the first surface side of the screen 10, so that the external light G1 is directed upward toward the first surface side of the screen 10. The amount of light reaching the image light L1 is significantly smaller than that of the image light L1. In addition, the external light G2 is reflected by the lens surface 132 and mainly heads downward on the first surface side of the screen 10, so it does not directly reach the observer O side, and even if it reaches the viewer O side, the amount of light G2 is It is significantly less than the light L1. Furthermore, some external light (not shown) is absorbed by the colored layer 122. Therefore, in the screen 10, it is possible to greatly suppress a decrease in image contrast due to external light G1, G2, etc.

From the above, according to the screen 10 of the present embodiment, a high-contrast, bright, and good image can be displayed, and reflection of the image on the ceiling or the like can be suppressed. Furthermore, according to the present embodiment, glare in images can be reduced.
Furthermore, according to the present embodiment, fine irregularities are formed on the surface of the surface layer 11, and the irregularities can diffuse the image light reflected toward the ceiling, etc., and reduce the reflection of the image on the ceiling, etc. The effect of suppressing crowding can be further enhanced.

Here, the screens of measurement examples 1 to 8, which differ in the ratio W1/P that the lens surface 132 occupies with respect to the arrangement pitch P, the presence or absence of the first curved surface part 134, etc. are prepared, and the reflection of the image on the ceiling etc. was evaluated.
The screens of Measurement Examples 1 to 8 have the same configuration except that the ratio of the lens surface 132, the presence or absence of a curved surface portion, the shape of the curved surface portion, etc. are different.
The screens of Measurement Examples 1 to 8 have a horizontally long rectangular shape and a screen size of 80 inches. The image source LS (manufactured by Hisense 75L9S) that projects image light onto the screens of measurement examples 1 to 8 was placed 741 mm below the screen in the vertical direction from point A on the screen of each measurement example (in the horizontal direction of the screen). Image light is projected from a point located at the center (236 mm downward from the bottom edge of the screen) and 447 mm away from the viewer side (+Z side) along the normal direction of the screen surface. Further, the angle α at the lower end of the screen in the vertical direction of the screen is 5.2°, and the angle α at the upper end of the screen is 21.8°. In the screen of each measurement example, the incident angle of the image light in the vertical direction of the screen at point A was 58.9°.

FIG. 6 is a diagram schematically showing the cross-sectional shape of the unit lens 131 at point A, which is the center of the screen in Measurement Examples 1 to 8. In FIG. 6, the unit lens 131 is shown in a cross section similar to that in FIG. 3(b), and only the lens layer 13 is shown for easy understanding.
6(a) corresponds to the unit lens 131 of the screen in measurement examples 1 to 3, FIG. 6(b) corresponds to the unit lens 131 of the screen in measurement example 4, and FIG. 6(c) corresponds to the unit lens 131 of the screen in measurement examples 1 to 3. 6(d) corresponds to the unit lens 131 of the screens of Measurement Examples 7 and 8.

In the screens of Measurement Examples 1 to 3, the non-lens surface 133 has a first curved surface portion 134 and a planar region 136, but does not have a second curved surface portion 135. The screen of measurement example 1 has a ratio W1/P of 60%, the screen of measurement example 2 has a ratio W1/P of 80%, and the screen of measurement example 3 has a ratio W1/P of 95%. .
In the screen of measurement example 4, the non-lens surface 133 has a first curved surface portion 134 and a second curved surface portion 135, and the ratio W1/P is 95%.
The screens of measurement examples 1 to 4 described above correspond to the screens of the examples of this embodiment.

In the screens of Measurement Examples 5 and 6, the non-lens surface 133 does not have the first curved surface portion 134 but has a planar region 136 and a second curved surface portion 135. The screen of Measurement Example 5 has a W1/P of 80%, and the screen of Measurement Example 6 has a W1/P of 95%.
In the screens of Measurement Examples 7 and 8, the non-lens surface 133 is planar and does not have the first curved surface portion 134 and the second curved surface portion 135. The screen of Measurement Example 7 has a ratio W1/P of 98%, and the screen of Measurement Example 8 has a ratio W1/P of 99%.
The screens of measurement examples 5 to 8 described above correspond to the screens of comparative examples of this embodiment.

In addition, for the screens of Measurement Examples 1 to 8, the speckle value at the geometric center was measured for nine areas obtained by dividing the screen into three in the vertical direction of the screen and in the horizontal direction of the screen. The standard deviation σ of the speckle values in the nine regions was determined.
FIG. 7 is a diagram showing each area of the screen when calculating the standard deviation σ of the speckle values. FIG. 7 shows a view of the screen as seen from the normal direction of the screen, and the nine areas are labeled S1 to S9.
In each of the screens of Measurement Examples 1 to 8, the lens layer 13 is a circular Fresnel lens in which unit lenses 131 are arranged concentrically around a point C (see FIG. 3(a)) outside the display area of the screen. It has a shape. In such a screen, regions S3 and S9 shown in FIG. 7 may have a small contribution to reducing the reflection of images on the ceiling etc. from the viewpoint of the arrangement direction of the unit lenses 131, etc., but the regions S3 and S9 shown in FIG. Since it is expected to be effective in reducing glare, the standard deviation σ for all nine areas was used.

Here, the speckle value is a value that serves as an index for evaluating glare in an image, and is a value obtained by the following equation (1).
Formula (1) S [%] = 100 x σa [cd/m ² ]/M [cd/m ² ]
Here, σa in equation (1) is the intersection point of a predetermined measurement area centered on the geometric center of each area of the screen, and line segments drawn at a predetermined pitch within the measurement area. is the standard deviation of the brightness at each measurement point when a white image is displayed on the screen. The measurement area is 40 mm in the vertical direction of the screen and 60 mm in the horizontal direction of the screen. Furthermore, the line segments have a pitch of 255 μm in the vertical direction of the screen and in the horizontal direction of the screen. Moreover, M indicates the average value of each luminance of the above-mentioned measurement points.

This speckle value is determined by measuring the speckle value by moving the measuring instrument (Dr.SPECKLE/SM01VS09 manufactured by Oxide Co., Ltd.) from point A, which is the center of the screen (geometric center of the screen), to the screen surface in a dark room environment. The speckle contrast Cs was obtained by arranging it at a position 1.0 m away from the viewer (+Z side) in the linear direction and measuring the speckle contrast Cs.
Also, at this time, the image source LS (75L9S manufactured by Hisense Co., Ltd.) was observed from point A on the screen of each measurement example 741 mm below the screen in the vertical direction (-Y side) along the normal direction of the sheet surface. It was placed at a position 447 mm away from the person's side (+Z side).

FIG. 8 is a diagram showing a table summarizing the evaluation results of image reflection on the screen ceiling and image glare in Measurement Examples 1 to 8.
Regarding the reflection of the image on the ceiling and the glare of the image, in a darkroom environment, the observer should move 3 degrees along the normal direction of the screen surface from point A, which is the center of each screen, to the observer side (+Z side). Evaluation was made by visually observing the display surface of the ceiling and screen at a position of .2 m.
In the table shown in Figure 8, the evaluation of the image reflection on the ceiling is ``weak'' if the reflection on the ceiling is weak and unclear, and can be used in good condition; Those that are stronger than "weak" but still usable are designated as "medium," and those that have a strong and clear reflection on the ceiling and are not suitable for use are designated as "strong."
In addition, in the evaluation of video glare (visibility of speckles), "weak" means that the video glare is weak and hardly visible, and can be used in good condition. The rating was ``medium'' if it was strong but usable, and the rating was ``strong'' if the image had strong glare and was not suitable for use.

As shown in the table of FIG. 8, the screens of measurement examples 1 to 4 that have the first curved surface part 134 have a higher degree of image reflection on the ceiling than the screens of measurement examples 5 to 8 that do not have the first curved surface part 134. was weak and reduced. In contrast, the screens of measurement examples 5 and 6 which do not have the first curved surface part 134 on the non-lens surface 133 and have the second curved surface part 135, and the screens of measurement examples 5 and 6 which do not have the first curved surface part 134 on the non-lens surface 133, The screens of Measurement Examples 7 and 8, which did not have any of these, had strong and clear reflection on the ceiling.
Furthermore, even in Measurement Example 1, where the ratio W1/P of the lens surface 132 to the arrangement pitch P is smaller than that of the screens of other measurement examples, a good bright image is displayed, and in all Measurement Examples 1 to 4, The image was displayed with sufficient brightness.
Therefore, the screen 10 has the first curved surface portion 134 in which the unit lens 131 is convex toward the first surface side, and the ratio W1/P is 60% or more and 95% or less to prevent the image from reaching the ceiling. This is preferable from the viewpoint of reducing glare.

Furthermore, as shown in the table of FIG. 8, the screens of Measurement Examples 1 to 4 in which the standard deviation σ of the speckle value was 1.38 or less had reduced glare (speckle) in the image. On the other hand, in the screens of measurement examples 5 to 8 where the standard deviation σ of the speckle value was larger than 1.38, glare in the images was visually recognized.

As described above, according to the present embodiment, the non-lens surface 133 has the first curved surface portion 134, and the ratio W1/P of the lens surface 132 to the arrangement pitch P is 60% or more and 95%. Since it is as follows, it is possible to suppress the reflection of the image on the ceiling while displaying a bright and good image.
Furthermore, according to the present embodiment, the screen has a standard deviation σ of speckle values in each of the nine divided areas of the screen, which is 1.38 or less, so that glare in the image can be reduced.

(Deformed form)
Various modifications and changes are possible without being limited to the embodiments described above, and these are also within the scope of the present invention.

(1) In the embodiment, the surface layer 11 has been described with reference to an example having a hard coat function and an anti-glare function, but the surface layer 11 is not limited to this. The layer may have one or more of various functions such as antifouling function and antistatic function, or may be formed by laminating a plurality of layers having the desired function. Further, a touch panel layer or the like may be provided as the surface layer 11.

(2) In the embodiment, the lens surface 132 may have a shape composed of a plurality of planes (so-called folded surface shape), or may have a curved shape that is convex toward the second surface side (-Z side). good.

(3) In the embodiment, the screen 10 may include a highly rigid transparent substrate layer made of glass or resin and having light transmittance, from the viewpoint of improving the flatness of the screen.
Further, a highly rigid support plate (not shown) or the like may be integrally laminated on the second surface side (-Z side) to improve the flatness of the screen.

(4) In the embodiment, the screen 10 may be flexible enough to be rolled up and stored when not in use.

(5) In the embodiment, the screen 10 shows an example in which the back protective layer 15 has light absorbing properties; however, the present invention is not limited to this, and the screen 10 has a form in which the back protecting layer 15 does not have light absorbing properties, and the second surface thereof is not limited to this. A form may be adopted in which a light-shielding curtain made of cloth or resin that does not easily transmit light, a layer that improves scratch resistance, etc. is laminated on the side (-Z side). In addition, if the environment in which the screen is used is such that a reduction in contrast due to external light from the second surface side is unlikely to occur, the screen 10 may have a form in which the back surface protective layer 15 does not have light absorbing properties, and the screen 10 may be configured as described above. It is also possible to adopt a form that does not include a light-shielding curtain or the like.
The back protection layer 15 may be made of paper, nonwoven fabric, resin sheet, etc., and may be laminated on the second surface side of the reflective layer 14 via a bonding layer formed of an adhesive or an adhesive (not shown). good.

(6) In the embodiment, the image source LS is arranged below the screen 10 (on the −Y side) in the vertical direction, but the present invention is not limited to this. It may be located above the screen 10 (on the +Y side). In this case, similarly to the video source LS, the screen 10 is used with its vertical direction reversed so that the Fresnel center point C is located on the upper side in the vertical direction.

(7) In the embodiment, the surface layer 11 may have a shape in which unit optical shapes (not shown) convex toward the first surface are arranged in the horizontal direction of the screen, with the vertical direction of the screen being the longitudinal direction. This unit optical shape has, for example, a partial circular cross-sectional shape parallel to the arrangement direction and the thickness direction of the screen, and the surface layer 11 has a so-called lenticular lens shape on the first surface side. You can also use it as Further, the unit optical shape may have a cross-sectional shape that is a partial shape of an ellipse, or a shape that is a combination of a plurality of curved lines.
Further, the unit optical shape of the surface layer 11 is not limited to the above example, and may be a triangular shape in which the cross-sectional shape in a cross section parallel to the arrangement direction and the thickness direction of the screen is convex toward the first surface side.
By providing such a surface layer 11, the image light L is diffused in the horizontal direction of the screen by the unit optical shape, and the screen 10 can secure a sufficient viewing angle in the horizontal direction (X direction) of the screen.

(8) In the embodiment, the image source LS is an example in which a laser light source is used. A DLP projector using a mercury lamp may be used, or an image source using another light source such as an LED may be used.

(9) In the embodiment, the video display device 1 includes a windshield (not shown) that causes the screen 10 to reflect the video light L projected from the video source LS and further reflects the reflected light toward the viewer O. It is good also as a form provided. At this time, the windshield has the function of reflecting image light in addition to the function of a transparent window glass. Such a video display device is suitable as a head-up display mounted on a moving object such as an automobile. With conventional reflective screens, some unintended light (stray light) generated by reflection off the surface of the screen reaches the windshield or the ceiling inside the car, causing unintended projected images to be observed. , which could obstruct the driver's view. However, by using the screen 10 of the above-described embodiment in such a video display device, such unintended projected images can be suppressed and a good visibility can be ensured.

Note that this embodiment and the modified embodiments can be used in combination as appropriate, but a detailed explanation will be omitted. Furthermore, the present invention is not limited to the embodiments described above.

1 Video display device 10 Screen 11 Surface layer 12 Base layer 121 Light diffusion layer 122 Colored layer 13 Lens layer 131 Unit lens 132 Lens surface 133 Non-lens surface 134 First curved surface portion 135 Second curved surface portion 136 Planar region 14 Reflection Layer 15 Back protective layer LS Image source

Claims

A reflective screen that reflects and displays image light projected from an image source,
In the thickness direction of the reflective screen, the surface side on which the image light is projected is the first surface side, and the back surface side is the second surface side,
a lens layer having a Fresnel lens shape on the second surface side, in which unit lenses having a lens surface and a non-lens surface and convex on the second surface side are arranged;
a reflective layer formed on the unit lens and reflecting light;
Equipped with
The non-lens surface has a curved first curved surface portion at an end on the first surface side,
The first curved surface portion is located in a region adjacent to the lens surface of the adjacent unit lens on the non-lens surface,
The ratio of the dimension of the lens surface in the arrangement direction of the unit lenses to the arrangement pitch of the unit lenses is 60% or more and 95% or less;
A reflective screen featuring
The reflective screen according to claim 1,
The reflective screen has a screen divided into three areas in the vertical direction and the horizontal direction of the screen in the usage state to form a total of nine areas, and the standard deviation σ for the speckle value S of the nine areas is 1.38 or less. Something.
A reflective screen featuring
The reflective screen according to claim 1,
The non-lens surface has a curved second curved surface portion at an end on the second surface side,
The radius of curvature of the first curved surface portion is larger than the radius of curvature of the second curved surface portion;
A reflective screen featuring
The reflective screen according to claim 3,
The non-lens surface has a planar region between the first curved surface portion and the second curved surface portion,
The angle corresponding to the apex angle of the unit lens and at which the extension direction of the lens surface and the extension direction of the planar area intersect is an acute angle;
A reflective screen featuring
The reflective screen according to claim 1,
In a cross section parallel to the arrangement direction of the unit lenses and the thickness direction of the reflective screen, the angle corresponds to the apex angle of the unit lens, and is the closest to the first surface in the extension direction of the lens surface and the non-lens surface. The angle at which the tangential direction intersects the point equidistant from the point closest to the second surface is an acute angle;
A reflective screen featuring
The reflective screen according to claim 1,
The lens layer has a circular Fresnel lens shape in which the unit lenses are arranged concentrically around a point located outside the display area of the reflective screen;
A reflective screen featuring
The reflective screen according to claim 1,
providing a colored layer colored to a predetermined density on the first surface side relative to the reflective layer;
A reflective screen featuring
The reflective screen according to claim 1,
Providing a light diffusion layer that diffuses incident light on the first surface side relative to the reflective layer;
A reflective screen featuring
The reflective screen according to any one of claims 1 to 8,
an image source that projects image light onto the reflective screen;
A video display device comprising: