JP2018124315A - Screen and video display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen for displaying a video on both sides with high transparency, and a video display device including the same.SOLUTION: A screen which reflects video light projected from a video source to display a video on both side includes: first reflection layer parts 131 arranged in a predetermined position along a screen surface in the screen, extending in a band shape in a direction crossing the arrangement direction, and reflecting part of incident light toward a first surface; and second reflection layer parts 132 arranged between adjacent first reflection layer parts 131 to reflect at least a part of the light passing through the first reflection layer parts 131 toward a second surface. The first and second reflection layer parts 131, 132 are formed of a dielectric multiplayer film. A low-refractive index dielectric film with a thickness of at least 0.5 μm is located in the second reflection layer part 132 closest to the second surface in the thickness direction, at least.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a screen that reflects projected image light and displays it on both sides, and an image display device including the screen.

  2. Description of the Related Art Conventionally, various types of reflective screens that display video by reflecting or transmitting video light projected from a video source have been developed (see, for example, Patent Document 1). In particular, translucent screens with transparency have the advantage that the scenery on the other side of the screen can be seen through when not in use when no image light is projected. It is growing.

Japanese Patent Laid-Open No. 9-11003

However, when such a transflective screen is provided with a light diffusing layer containing diffusing particles that diffuse light, the scenery on the other side of the screen may be observed as whitish and blurred. Therefore, improvement of transparency has been a problem.
There has also been a demand for displaying images on both the image source side and the back side of the screen while having transparency.

  Patent Document 1 described above proposes a screen that can be used for both a transmission type and a reflection type. However, this Patent Document 1 does not disclose any measures for improving the transparency. Further, Patent Document 1 does not disclose that an image is displayed on both surfaces of the screen by image light projected on one surface of the screen.

  An object of the present invention is to provide a screen that is highly transparent and capable of displaying images on both sides, and an image display device including the screen.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
A first invention is a screen that displays image on both sides by reflecting image light (L) projected from an image source (LS), the first surface (10a) on which image light is incident, and the first surface A second surface (10b) opposite to one surface is used as both surfaces, and a plurality of light beams are arranged in a predetermined direction along the screen surface in the screen, extend in a band shape in a direction crossing the arrangement direction, and incident light. Of the first reflection layer portion that reflects a part of the first reflection layer to the first surface side and transmits at least a part of the other incident light to the second surface side, and the adjacent first reflection layer portion. A second reflective layer part (132) provided in between for reflecting at least part of the light transmitted through the first reflective layer part to the second surface side, the first reflective layer part and the first reflective layer part 2 In the cross section parallel to the direction of arrangement of the reflective layers and the thickness direction of the screen, The first reflective layer portion forms an angle θ1 with respect to a plane parallel to the screen surface, and the second reflective layer portion forms an angle θ2 larger than the angle θ1 with respect to a plane parallel to the screen surface, The first reflective layer portion and the second reflective layer portion are rough surfaces having irregular irregular shapes on the surface, and a dielectric multilayer film in which a plurality of dielectric films having different refractive indexes are alternately stacked in the thickness direction. Two dielectric films having different refractive indexes at least on the second surface side in the thickness direction of the second reflective layer portion of the first reflective layer portion and the second reflective layer portion. The screen (10) is characterized in that a low-refractive-index dielectric film having a lower refractive index than that of one of the dielectric films is located and has a thickness of 0.5 μm or more.
According to a second aspect of the present invention, in the screen of the first aspect, in the thickness direction of the screen, on the second surface (10b) side of the first reflective layer portion (131) and the second reflective layer portion (132). The adjacent layer (14) has a refractive index of 1.56 to 1.7, and the low refractive index dielectric film has a refractive index of 1.33 to 1.47. (10).
According to a third invention, in the screen of the first invention or the second invention, the low refractive index dielectric that is located closest to the second surface (10b) in the thickness direction of at least the second reflective layer portion (132). The body membrane is a screen (10) characterized in that its thickness is 3.0 μm or less.
According to a fourth invention, in any one of the screens from the first invention to the third invention, in the cross section parallel to the arrangement direction of the second reflective layer portions (132) and the thickness direction of the screen, The screen (10) is characterized in that the angle φ formed by the two reflective layer portions with the direction orthogonal to the screen surface satisfies 0 <φ <2 × (θ1).
According to a fifth aspect of the present invention, in any one of the screens from the first aspect to the fourth aspect, the first surface (121a) on which the image light is incident on the surface on the second surface (10b) side; The first reflective layer portion (131) has an optical shape layer (12) in which a plurality of unit optical shapes (121) having a second surface (121b) facing the first surface are arranged, The screen (10) is provided on at least a part of the first surface, and the second reflective layer portion (132) is provided on at least a part of the second surface. .
A sixth invention is the screen of the fifth invention, wherein the unit optical shape (121) is a partial shape of a perfect circle when viewed from the front direction of the screen, and a plurality of concentric circles are arranged, It is the screen (10) characterized by these.
According to a seventh invention, in any one of the screens from the first invention to the sixth invention, the screen is characterized by not including a light diffusion layer containing diffusion particles having a function of diffusing light. (10).
An eighth invention is a video display device (1) comprising any one screen (10) from the first invention to the seventh invention, and a video source (LS) for projecting video light onto the screen. It is.

  According to the present invention, it is possible to provide a screen having high transparency and capable of displaying an image on both sides, and an image display device including the screen.

It is a figure showing picture display device 1 of an embodiment. It is a figure which shows the layer structure of the screen 10 of embodiment. It is the figure which looked at the 1st optical shape layer 12 of an embodiment from the back side (-Z side). It is a figure explaining the unit optical shape 121, the reflection layer 13, and the 2nd optical shape layer 14 of embodiment. It is a figure which shows the mode of the image light and external light in the screen 10 of embodiment.

Embodiments of the present invention will be described below with reference to the drawings. In addition, each figure shown below including FIG. 1 is the figure shown typically, and the magnitude | size and shape of each part are exaggerated suitably for easy understanding.
In this specification, terms that specify shape and geometric conditions, for example, terms such as parallel and orthogonal, are strictly meanings, have similar optical functions, and can be regarded as parallel and orthogonal It also includes a state having an error of.
In addition, the numerical values such as the dimensions of the respective members and the material names described in the present specification are examples of the embodiment, and are not limited thereto, and may be appropriately selected and used.

In this specification, words such as a plate and a sheet are used. In general, the plates are used in the order of thickness, in the order of plate, sheet, and film, and are used in this specification as well. However, there is no technical meaning in such proper use, so these terms can be replaced as appropriate.
In the present specification, the screen surface indicates a surface in the plane direction of the screen when viewed as the entire screen, and is assumed to be parallel to the screen (display surface) of the screen.

(Embodiment)
FIG. 1 is a diagram showing a video display device 1 of the present embodiment. 1A is a perspective view of the video display device 1, and FIG. 1B is a view of the video display device 1 as viewed from the side.
The video display device 1 includes a screen 10, a video source LS, and the like. The screen 10 of the present embodiment reflects the image light L projected from the image source LS, and can display an image on the image source side screen and the back side screen. Details of the screen 10 will be described later.

Here, for easy understanding, an XYZ orthogonal coordinate system is provided as appropriate in each of the following drawings including FIG. In this coordinate system, the horizontal direction (horizontal direction) of the screen of the screen 10 is the X direction, the vertical direction (vertical direction) of the screen 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 10.
Further, when viewed from the observer O1 positioned in the front direction on the image source side of the screen 10, the direction toward the right side in the horizontal direction of the screen (horizontal direction) is + X direction, and the direction toward the upper side of the screen vertical direction (vertical direction). The direction from the back side (back side) to the image source side in the + Y direction and the thickness direction is defined as the + Z direction.
Further, in the following description, the screen vertical direction, the screen horizontal direction, and the thickness direction are the screen vertical direction (vertical direction), the screen horizontal direction (horizontal direction) in the usage state of the screen 10 unless otherwise specified, The thickness direction (depth direction) is parallel to the Y direction, the X direction, and the Z direction, respectively.

The video source LS is a video projection device that projects the video light L onto the screen 10, and is, for example, a short focus projector.
The video source LS is displayed when the screen (display area) of the screen 10 is viewed from the front direction (normal direction of the screen surface) on the video source side (+ Z side) when the video display device 1 is in use. Is located at the center in the left-right direction of the screen and on the lower side in the vertical direction (−Y side) than the screen of the screen 10.
The image source LS can project the image light L obliquely in a depth direction (Z direction) from a position where the distance from the surface of the screen 10 is significantly closer than that of a conventional general-purpose projector. Therefore, compared with the conventional general-purpose projector, the video source LS has a short projection distance to the screen 10 and a large incident angle at which the projected video light is incident on the screen 10, and its change amount (from the minimum value to the maximum value). The amount of change) is also large.

The screen 10 is a translucent screen having transparency so that the scenery on the other side of the screen 10 can be observed when not in use when no image light is projected. Further, the screen 10 reflects a part of the image light L projected by the image source LS toward the observer O1 located on the image source side (+ Z side), displays an image, and also displays a part of the image light. This is a screen that displays an image by emitting light toward an observer O2 (see FIG. 5) located on the back side (back side), that is, a screen that displays images on both sides.
The screen 10 is a surface on the image source side in the thickness direction, and is a first surface 10a on which the image light L projected by the image source LS is incident and a surface on the back side facing the first surface 10a. The second surface 10b from which a part is emitted is defined as both surfaces.
The screen (display area) of the screen 10 has a substantially rectangular shape in which the long side direction is the left-right direction of the screen (X direction) when viewed from the viewer O1 side on the video source side (+ Z side).
The screen 10 has a screen size of about 40 to 100 inches diagonal and a screen aspect ratio of 16: 9. However, the present invention is not limited to this, and for example, the size may be 40 inches or less, and the size and shape can be appropriately selected according to the purpose of use, the usage environment, and the like.

In general, the screen 10 is a laminated body of thin layers made of a resin, etc., and the screen 10 alone often does not have sufficient rigidity to maintain flatness. Therefore, the screen 10 according to the present embodiment integrally bonds a support plate (not shown) via a bonding layer (not shown) having optical transparency on the back side (−Z side) or the image source side (+ Z side) (or It is preferable that the flatness of the screen be maintained.
Such a support plate is a flat plate member having light transmittance and high rigidity, and a plate member made of resin such as acrylic resin or PC resin, or glass can be used.
The video display device 1 of the present embodiment is applied to a show window such as a store, for example. At this time, it is preferable that the screen 10 is joined with a window glass (glass plate) of the show window as a support plate to maintain the flatness of the screen.
However, the present invention is not limited to this, and the screen 10 may be configured such that its four sides are supported by a frame member (not shown) and the like so as to maintain its flatness.

FIG. 2 is a diagram illustrating a layer configuration of the screen 10 according to the present embodiment. In FIG. 2, it passes through a point A (see FIG. 1) that is the screen center (the geometric center of the screen) on the image source side (+ Z side) of the screen 10, and is parallel to the screen vertical direction (Y direction). A part of a cross section perpendicular to the screen surface (parallel to the Z direction which is the thickness direction) is enlarged.
FIG. 3 is a view of the first optical shape layer 12 of the present embodiment as viewed from the back side (−Z side). In order to facilitate understanding, the reflective layer 13, the second optical shape layer 14, the protective layer 15 and the like are omitted.
FIG. 4 is a diagram illustrating the unit optical shape 121, the reflective layer 13, and the second optical shape layer 14 of the present embodiment. FIG. 4 shows a further enlarged cross section of the screen 10 shown in FIG. 2, and only the first optical shape layer 12, the reflective layer 13, and the second optical shape layer 14 are shown for easy understanding. .
As shown in FIG. 2, the screen 10 includes a base material layer 11, a first optical shape layer 12, a reflective layer 13, a second optical shape layer 14, and a protective layer 15 in order from the image source side (+ Z side). ing.

The base material layer 11 is a sheet-like member having optical transparency. As for the base material layer 11, the 1st optical shape layer 12 is integrally formed in the back surface side (back surface side, -Z side). The base material layer 11 is a layer that becomes a base material (base) for forming the first optical shape layer 12.
The base material layer 11 is made of, for example, polyester resin such as PET (polyethylene terephthalate) having high light transmittance, acrylic resin, styrene resin, acrylic styrene resin, PC (polycarbonate) resin, alicyclic polyolefin resin, TAC (triacetyl). Cellulose) resin or the like.

The first optical shape layer 12 is a light-transmitting layer formed on the back side (−Z side) of the base material layer 11. A plurality of unit optical shapes (unit lenses) 121 are arranged on the back surface (−Z side) of the first optical shape layer 12.
As shown in FIG. 3, the unit optical shape 121 is a partial shape (arc shape) of a perfect circle when viewed from the front direction (Z direction), and a point C positioned outside the screen (display area) of the screen 10. A plurality of concentric circles are arranged as the center. That is, the first optical shape layer 12 has a circular Fresnel lens shape having a so-called offset structure with the point C as the center (Fresnel center).
In the present embodiment, as shown in FIG. 3, the point C is located at the center of the screen 10 in the left-right direction (X direction) and below the screen. Further, when the screen 10 is viewed from the front direction, the point C and the point A are located on the same straight line parallel to the screen vertical direction (Y direction) as shown in FIG.

As shown in FIG. 2 and the like, the unit optical shape 121 is a substantially triangular shape in which a cross-sectional shape parallel to the thickness direction of the screen 10 and the arrangement direction of the unit optical shapes 121 is convex on the back side (−Z side). .
The unit optical shape 121 has a first slope (lens surface) 121a on which image light is incident and a second slope (non-lens surface) 121b facing the first slope. In one unit optical shape 121, the second inclined surface 121b is located on the lower side (−Y side) of the first inclined surface 121a with the apex t interposed therebetween.
The first inclined surface 121a and the second inclined surface 121b of the unit optical shape 121 have fine and irregular uneven shapes.

The angle formed by the first slope 121a and a plane parallel to the screen surface is θ1. The angle formed by the second inclined surface 121b and a plane parallel to the screen surface is θ2. The vertex angle of the unit optical shape 121 is θ3. The angles θ1 and θ2 satisfy the relationship θ2> θ1. The apex angle of the unit optical shape 121 is θ3.
The arrangement pitch of the unit optical shapes 121 is P, and the height of the unit optical shapes 121 (the dimension from the vertex t in the thickness direction to the point v that becomes the valley bottom between the unit optical shapes 121) is h.

In order to facilitate understanding, FIGS. 2 and 4 show examples in which the arrangement pitch P and the angles θ 1 and θ 2 of the unit optical shapes 121 are constant in the arrangement direction of the unit optical shapes 121. However, in the unit optical shape 121 of this embodiment, the arrangement pitch P is actually constant, but gradually increases as the angle θ1 moves away from the point C that becomes the Fresnel center in the arrangement direction of the unit optical shapes 121. .
The angles θ1, θ2, the array pitch P, and the like are the projection angle of the image light from the image source LS (the incident angle of the image light to the screen 10), the size of the pixels (pixels) of the image source LS, the screen of the screen 10 You may set suitably according to a size, the refractive index of each layer, etc. For example, the arrangement pitch P and the angles θ1 and θ2 may be changed along the arrangement direction of the unit optical shapes 121.

The first optical shape layer 12 is formed of an ultraviolet curable resin such as urethane acrylate, polyester acrylate, epoxy acrylate, polyether acrylate, polythiol, or butadiene acrylate having high light transmittance. The first optical shape layer 12 has the same or substantially the same refractive index as the second optical shape layer 14 and the base material layer 11 described later (the difference in refractive index is small enough to be regarded as equal), so that the transparency of the screen 10 From the viewpoint of improving the ratio.
The refractive index of the first optical shape layer 12 of the present embodiment is about 1.56 to 1.7.
In the present embodiment, the resin constituting the first optical shape layer 12 will be described using an ultraviolet curable resin as an example, but is not limited thereto, and other ionizing radiation such as an electron beam curable resin is used. You may form with curable resin.

The reflective layer 13 is a layer having a function of reflecting light, and is formed on the unit optical shape 121 (on the first slope 121a and the second slope 121b). The reflective layer 13 includes a first reflective layer portion 131 formed on the first slope 121a and a second reflective layer portion 132 formed on the second slope 121b.
The reflection layer 13 is a so-called half mirror that reflects a part of incident light and transmits at least a part of other incident light.
As described above, the first inclined surface 121a and the second inclined surface 121b are formed with fine and irregular uneven shapes, and the reflective layer 13 is formed following the uneven shape. The film is formed while maintaining it. Therefore, the surface on the first optical shape layer 12 side and the surface on the second optical shape layer 14 side of the reflective layer 13 are rough surfaces having fine and irregular irregular shapes.
The reflective layer 13 has a function of diffusing and reflecting a part of incident light by this uneven shape and transmitting at least a part of other incident light without diffusing.

The reflective layer 13 includes two dielectric films having different refractive indexes, that is, a dielectric film having a high refractive index (hereinafter referred to as a high refractive index dielectric film) and a dielectric film having a low refractive index (hereinafter referred to as a low refractive index dielectric). And a dielectric multilayer film formed by alternately laminating a plurality of layers.
The high refractive index dielectric film is formed of, for example, TiO ₂ (titanium dioxide), Nb ₂ O ₅ (niobium pentoxide), Ta ₂ O ₅ (tantalum pentoxide), or the like. The refractive index of the high refractive index dielectric film is about 2.0 to 2.6.
The low refractive index dielectric film is formed of, for example, SiO ₂ (silicon dioxide), MgF ₂ (magnesium fluoride), or the like. The refractive index of the low refractive index dielectric film is about 1.33 to 1.47.

The reflective layer 13 (the first reflective layer portion 131 and the second reflective layer portion 132) has 2-10 layers of high-refractive index dielectric films and low-refractive index dielectric films alternately having a film thickness of about 5 to 100 nm. It is formed by stacking. In the second reflective layer portion 132, the thickness of the second optical shape layer 14 side (the second surface 10b side) is thicker than other high refractive index dielectric films and low refractive index dielectric films. A refractive index dielectric film is located.
The low refractive index dielectric film located closest to the second optical shape layer 14 has a film thickness from the viewpoint of efficiently totally reflecting the image light at the interface between the second reflective layer portion 132 and the second optical shape layer 14. Is preferably 0.5 μm or more. Further, from the viewpoint of maintaining a fine and irregular uneven shape on the surface of the reflective layer 13 and sufficiently diffusing reflected light at the interface, the thickness is preferably 3.0 μm or less.

By providing the dielectric multilayer film so that such a thick low refractive index dielectric film is located closest to the second optical shape layer 14, the second optical shape layer 14 side (second surface 10b side) is provided. ) Efficiently reflects the image light (including total reflection) at the interface between the low refractive index dielectric film and the second optical shape layer 14 and directs the image light to the viewer side located on the back side (−Z side). Can be directed.
In the present embodiment, in addition to the second optical shape layer 14 side (second surface 10b side) of the second reflective layer portion 132, the second optical shape layer 14 side of the first reflective layer portion 131 (second surface). A low-refractive-index dielectric film having a thickness of 0.5 μm or more is also formed on the surface 10 b side). It is good also as a form formed only in the 2nd surface 10b side).

In the present embodiment, the reflective layer 13 has a reflectance of about 5 to 45% and a transmittance of about 55 to 85% with respect to light having a wavelength range of 400 to 800 nm.
In addition, the reflective layer 13 of the present embodiment alternately includes a high refractive index dielectric film formed of a metal oxide film such as TiO ₂ (titanium dioxide) and a low refractive index dielectric film formed of SiO _2. It is formed of a dielectric multilayer film formed by laminating a plurality.
In the present embodiment, the high refractive index dielectric film and the low refractive index dielectric multilayer film as described above are alternately deposited on the unit optical shape 121 (on the first slope 121a and the second slope 121b), or Each film is sequentially laminated with a predetermined thickness by sputtering or the like to form a dielectric multilayer film, and the reflective layer 13 is formed. Various conditions such as vapor deposition are appropriately adjusted for the low refractive index dielectric film having a film thickness of 0.5 μm or more located on the second optical shape layer 14 side (second surface 10b side) closest to the second reflective layer portion 132. And so on.

The reflective layer 13 is not limited to this, and for example, a highly light reflective metal such as aluminum, silver, or nickel is deposited, a highly light reflective metal is sputtered, or a metal foil is transferred. It may be formed by, for example.
As in this embodiment, the reflective layer 13 formed of a dielectric multilayer film has higher transparency than a reflective layer formed of a metal deposition film such as aluminum, Absorption loss is small and high reflectance can be realized.

As shown in FIG. 4, among the image light La incident on the first inclined surface 121 a of the unit optical shape 121, a part of the image light Lb is reflected by the first reflection layer portion 131, and the image source side (+ Z side) ) To the observer O1 side. At this time, the image light Lb reflected by the first reflective layer 131 is diffused by a fine and irregular uneven shape of the reflection surface.
Further, a part of the image light Lc incident on the first inclined surface 121a is transmitted through the reflective layer 13 and is emitted above the screen on the back side (−Z side).

Furthermore, at least a part of the image light Ld incident on the region B near the point v serving as the valley bottom in the first inclined surface 121a and transmitted through the first reflective layer 131 is the second inclined surface of the adjacent unit optical shape 121. Incident on 121b. In the second reflective layer portion 132, the low refractive index dielectric film having a thickness of 0.5 μm or more is located closest to the second optical shape layer 14 side. Accordingly, the image light Ld is reflected (including total reflection) at the interface between the second reflective layer portion 132 and the second optical shape layer 14, and is observed in the front direction on the back side (−Z side) of the screen 10. The person O2 (see FIG. 5 described later) emits the image in a direction in which the image can be visually recognized. At this time, the image light Ld reflected by the second reflective layer portion 132 is diffused by a fine and irregular uneven shape on the surface of the second reflective layer portion 132.
In addition, in the second reflective layer portion 132, the low refractive index dielectric film located closest to the second optical shape layer 14 has a thickness of 0.5 μm or more, and most of the image light Ld is in the second reflective layer portion. Total reflection is performed at the interface between the second optical shape layer 14 and 132. Therefore, it is possible to increase the amount of the image light Ld toward the back side and display a bright and good image on the back side.

The image light Ld incident on the region B and transmitted through the first reflective layer 131 is incident on the second inclined surface 121b, reflected by the second reflective layer 132, and located on the back side (−Z side). When the light is emitted to the O2 side and the focal point is infinite, the angle φ formed by the second inclined surface 121b with respect to the direction orthogonal to the screen surface is preferably 0 <φ <2 × (θ1), where φ is More preferably, it is substantially equal to θ1 (a state having an error that can be regarded as equal), and more preferably φ is equal to θ1.
When the angle φ is 0 °, the image light reflected by the second reflective layer portion 132 is emitted to the lower side of the back surface, and thus does not reach the observer O2. Further, when the angle φ is 2 × (θ1) or more, the image light reflected by the second reflective layer portion 132 does not enter the second inclined surface 121b, moves upward on the back surface, and does not reach the observer O2. Therefore, the angle φ is preferably in the above range.

Also, as the angle φ approaches the angle θ1, the apex angle θ3 approaches 90 °, and when the angle φ is equal to the angle θ1, the apex angle θ3 is equal to 90 °. When the apex angle θ3 = 90 °, the region B is a region having a dimension S1 = Psin (θ1) tan (θ1) from the point v along the first slope 121a toward the apex t.
When the focus position of the image light Ld emitted to the back side is not infinite and is a predetermined position, the relationship between the angle φ and the angle θ1 is not limited to the above. Also, the size of the apex angle θ3 may be appropriately selected according to the position of the focus of the image light Ld.

The second optical shape layer 14 is a light-transmitting layer provided on the back side (−Z side) of the first optical shape layer 12 and the reflection layer 13. The second optical shape layer 14 is provided so as to fill the concave and convex valleys of the unit optical shape 121, and the first optical shape layer 12 and the back surface side (−Z side) of the reflection layer 13 are flat. The surface on the image source side (+ Z side) of the second optical shape layer 14 is formed by arranging a plurality of substantially reverse shapes of the unit optical shapes 121 of the first optical shape layer 12.
By providing the second optical shape layer 14 as described above, the reflective layer 13 can be protected, the protective layer 15 and the like can be easily laminated on the back side, and the joining to the support plate and the like is facilitated.

The refractive index of the second optical shape layer 14 is larger than the refractive index of the low refractive index dielectric film located closest to the second optical shape layer 14 of the second reflective layer portion 132, and this low refractive index dielectric film and From the viewpoint of efficiently reflecting image light at the interface with the second optical shape layer 14, it is preferably about 1.56 to 1.7.
The second optical shape layer 14 is preferably formed using an ultraviolet curable resin such as urethane acrylate or epoxy acrylate.

The protective layer 15 is a light-transmitting layer provided on the back side (−Z side) of the second optical shape layer 14, and has a function of protecting the back side (−Z side) of the screen 10. ing.
The protective layer 15 is preferably a sheet-like member formed of a highly light transmissive resin. For example, the protective layer 15 may be a sheet-like member formed using the same material as the base material layer 11 described above.
As described above, the screen 10 of the present embodiment does not include a light diffusion layer containing a diffusing material such as particles having a diffusing action for diffusing light, and the light reflected by the reflective layer 13 is fine on the surface. And it is diffused by irregular uneven shape.

The screen 10 is manufactured by the following manufacturing method, for example.
A base material layer 11 is prepared, and on one surface thereof, a molding die for shaping the unit optical shape 121 is laminated in a state filled with an ultraviolet curable resin, and the resin is cured by irradiating ultraviolet rays. The first optical shape layer 12 is formed. At this time, fine and irregular concavo-convex shapes are formed on the surfaces on which the first inclined surface 121a and the second inclined surface 121b of the mold for forming the unit optical shape 121 are formed. This uneven shape can be formed by performing surface treatment a plurality of times on the surfaces that shape the first inclined surface 121a and the second inclined surface 121b of the mold. This surface processing is, for example, plating, etching, blasting, or the like. Further, the surface processing may be performed a plurality of times by changing various conditions.

  After the first optical shape layer 12 is formed on one surface of the base material layer 11, a dielectric multilayer film is formed on the first inclined surface 121a and the second inclined surface 121b by vapor deposition or sputtering, and the reflective layer 13 is formed. To do. At this time, as described above, by appropriately setting various conditions such as vapor deposition and sputtering, the film thickness is at least 0.5 μm at least on the second optical shape layer 14 side of the second reflective layer portion 132. A low refractive index dielectric film can be formed.

Thereafter, an ultraviolet curable resin is applied from above the reflective layer 13 so as to fill the concave and convex valleys of the unit optical shape 121, the protective layer 15 is laminated, and the ultraviolet curable resin is cured to form the second optical shape. The layer 14 and the protective layer 15 are integrally formed. Thereafter, the screen 10 is completed by cutting into a predetermined size.
The base material layer 11 and the protective layer 15 may be a single wafer shape or a web shape.

Conventionally, as a method for forming a fine and irregular concavo-convex shape on the surface of the reflective layer 13, for example, a diffusion particle or the like is applied on the first slope 121 a and the second slope 121 b, and the reflective layer 13 is formed thereon. Or a method of forming the reflective layer 13 after blasting the first slope 121a and the second slope 121b is known. However, in such a manufacturing method, dispersion | variation in the diffusion characteristic, quality, etc. in each screen 10 is large, and stable manufacture cannot be performed.
On the other hand, as described above, after the fine and irregular uneven shape of the first inclined surface 121a and the second inclined surface 121b is formed by the mold, the reflective layer 13 is formed on the first inclined surface 121a and the second inclined surface 121b. By forming a film, it is possible to easily form fine irregular irregular shapes on the surface of the reflective layer 13, and even when a large number of screens 10 are manufactured, there is little variation in diffusion characteristics and quality, and the manufacturing is stable. it can.

FIG. 5 is a diagram illustrating a state of the image light and the external light on the screen 10 of the present embodiment. In FIG. 5, a part of a cross section is enlarged through a point A that is the center of the screen 10 and parallel to the arrangement direction (Y direction) of the unit optical shapes 121 and the thickness direction (Z direction) of the screen. Show. Further, in FIG. 5, there is no difference in refractive index between the base layer 11 and the first optical shape layer 12 and between the second optical shape layer 14 and the protective layer 15 for easy understanding. Shown as a thing.
Among the image light L1 projected from the image source LS located below the screen 10 and obliquely incident on the screen 10 from below, a part of the image light L2 is reflected on the surface of the screen 10 and travels upward. The observer O1 positioned in the front direction on the image source side of the screen 10 does not reach. Of the image light L1, the image light L3 incident on the screen 10 is incident on the first inclined surface 121a of the unit optical shape 121, is diffusely reflected by the reflective layer 13 (first reflective layer portion 131), and is on the image source side. The light is emitted to the observer O1 side located in the (+ Z side) front direction. Therefore, the observer O1 can visually recognize an image having a good viewing angle.

Of the image light incident on the first inclined surface 121a, a part of the image light L4 that has not been reflected by the reflective layer 13 is transmitted through the reflective layer 13 (first reflective layer portion 131), and the back side (− The light is emitted upward from the Z side. Therefore, the video light L4 does not reach the observer O2 located in the front direction of the screen 10 on the back side.
The image light L5 incident on the region B in the vicinity of the point v serving as the valley bottom of the first inclined surface 121a is partially diffused and reflected by the first reflective layer 131 and emitted to the observer O1 side. In addition, a part of the image light L7 out of the image light L5 transmits the reflection layer 13 (first reflection layer portion 131) and is adjacent to the second reflection layer portion 132 and the second optical shape layer of the second inclined surface 121b. Most of the light is totally reflected at the interface with 14. At this time, the light is diffused in a fine and irregular shape on the surface of the second reflective layer portion 132, and is emitted to the viewer O2 side positioned in the front direction of the screen on the back side. With this video light L7, the viewer O2 on the back side can visually recognize a bright and good video.

  In the present embodiment, the image light L5 is projected from below the screen 10, and the angle θ2 (see FIG. 2, FIG. 4, etc.) is the incident angle of the image light at each point in the screen vertical direction of the screen 10. Bigger than. Therefore, the image light does not directly enter the second reflective layer portion 132 without passing through the first reflective layer portion 131.

Next, light from the outside such as sunlight other than the image light incident on the screen 10 from the back side (−Z side) or the image source side (+ Z side) (hereinafter referred to as external light) will be described.
As shown in FIG. 5, out of the external lights G1 and G5 that are incident on the screen 10 from above, some of the external lights G2 and G6 are reflected by the surface of the screen 10 and travel downward to the screen 10, respectively. Further, a part of the external light G3 is reflected by the reflective layer 13 and is emitted above the screen on the image source side. A part of the external light G7 is reflected by the reflective layer 13 and is emitted below the screen 10 on the back side. Also, some of the external lights G4 and G8 are transmitted through the reflective layer 13 and emitted to the lower side of the screen 10 on the back side and the video source side, respectively.
Therefore, since the external lights G3, G4, G7, and G8 do not reach the observers O1 and O2, it is possible to suppress a decrease in image contrast due to external light.

  Further, since the screen 10 is not provided with a light diffusing layer containing diffusing particles or the like that diffuses light, external light G9 and G10 incident on the screen surface at a small incident angle pass through the screen 10 without being diffused. . Therefore, when the observers O1 and O2 observe the scenery on the other side of the screen 10 through the screen 10 from the image source side and the rear side, the scenery on the other side of the screen 10 does not blur or blur in white. It can be observed with high transparency.

In conventional transflective reflective screens with a light diffusing layer that contains diffusing particles that diffuse light, etc., external light is also diffused by the diffusing particles, so that the scenery on the other side of the screen is blurred or whitened. Observed, and the contrast of the image is lowered. In addition, in the conventional transflective reflective screen as described above, the image light is diffused twice before and after reflection by the reflective layer, so that a good viewing angle can be obtained while the brightness is reduced, There is a problem that the resolution of the video is lowered.
However, in the screen 10 of the present embodiment, the image light is diffused when it is reflected (including total reflection) by the fine and irregular uneven shape of the reflection layer 13. Moreover, in the screen 10 of this embodiment, the light which permeate | transmits the reflection layer 13 is not spread | diffused.

Therefore, according to the present embodiment, the screen 10 can display an image having a favorable viewing angle, brightness, and resolution to the observer O1 on the image source side (+ Z side) and in a state where no image light is projected. The scenery on the other side (−Z side) of the screen 10 is not visually blurred or blurred, and can be seen well by the observer O1, and high transparency of the screen 10 can be realized.
Further, according to the present embodiment, the screen 10 is an image that is horizontally reversed with respect to the observer O2 located on the back side (−Z side) by projecting image light from the image source LS. Bright and good images can be displayed. Thereby, it is possible to notify the observer O2 on the back side of the screen 10 of the presence of the image, and to guide the observer O2 to the image source side where the image can be viewed better. In addition, since the screen 10 has high transparency as described above, the scenery on the other side (+ Z side) of the screen 10 is favorably visually recognized by the observer O2 in a state where no image light is projected. .

In addition, according to the present embodiment, the screen 10 does not diffuse the light transmitted through the reflective layer 13 and has high transparency. Therefore, even when image light is projected on the screen 10, the viewer can observe the screen 10. O1 and O2 can partially view the scenery beyond the screen 10 (back side, video source side).
In addition, according to the present embodiment, the first optical shape layer 12 has a point C serving as the Fresnel center located outside the display region and on the image source LS side, so-called a circular Fresnel lens shape having an offset structure. Therefore, even in the case of image light with a large incident angle projected from the short-focus image source LS, the image in the horizontal direction of the screen does not become dark, and the brightness is highly uniform. Video can be displayed.

(Deformation)
The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the scope of the present invention.
(1) In the embodiment, the transmittance of the first reflective layer portion 131 may be larger than that of the second reflective layer portion 132. By adopting such a configuration, the amount of light that is displayed on the back side can be increased, and a good image can be displayed on the back side while displaying a good image on the image source side as a reflective screen. Can be displayed.

(2) In the embodiment, as the reflective layer 13, between the first slope 121a and the second optical shape layer 14 of the first optical shape layer 12, and between the second slope 121b and the second optical shape layer 14, One or a plurality of layers having a refractive index different from the refractive index of the first optical shape layer 12 (for example, a layer formed of an air layer or an organic multilayer film) may be provided.

(3) In the embodiment, a hard coat layer for preventing scratches may be provided on at least one of the image source side (+ Z side) surface and the back side (−Z side) surface of the screen 10. The hard coat layer is, for example, a surface on the image source side of the screen 10 (in the embodiment, a surface on the image source side of the base material layer 11), a surface on the back side (in the embodiment, a surface on the back side of the protective layer 15). In addition, an ultraviolet curable resin (for example, urethane acrylate) having a hard coat function is applied and formed.
Further, not only the hard coat layer but also a layer having a necessary function such as an antireflection function, an ultraviolet absorption function, an antifouling function, an antistatic function, etc., depending on the use environment and purpose of use of the screen 10. One or a plurality may be selected and provided. Further, a touch panel layer or the like may be provided on the image source side of the base material layer 11 or the like.
For example, when an antireflection layer is provided on the image source side surface of the screen 10, in addition to the effect of suppressing the reflection of the image light on the image source side surface when entering the screen 10 and increasing the amount of incident light. A part of the image light reflected by the reflection layer 13 is reflected from the image source side surface of the screen 10 and emitted from the back side, so that the image quality of the image observed by the viewer O2 on the back side is degraded. Can also be suppressed.

(4) In the embodiment, the video source LS has been described by taking an example in which the video source LS is located at the center in the left-right direction of the screen 10 and is located on the lower side in the vertical direction. It is good also as a form which is arrange | positioned at the side etc. and projects image light from the oblique direction light in the screen left-right direction with respect to the screen 10.
At this time, it is preferable that the first optical shape layer 12 has a form in which the point C that is the Fresnel center of the circular Fresnel lens shape is shifted in accordance with the position of the video source LS. By adopting such a form, the position of the video source LS and the like can be freely set.

(5) In the embodiment, the first optical shape layer 12 has been described by taking an example having a circular Fresnel lens shape on the back side surface. It is good also as a form which has a substantially triangular prism shape made into a direction, and has the linear Fresnel lens shape arranged in multiple numbers by the up-down direction of the screen. Further, a plurality of unit prism shapes whose longitudinal direction is the horizontal direction of the screen may be arranged in the vertical direction of the screen.

(6) In the embodiment, the unit optical shape 121 is an example in which the first inclined surface 121a and the second inclined surface 121b are formed by planes. However, the present invention is not limited to this, and for example, a form in which a curved surface and a plane are combined. Alternatively, it may be a folded surface.
In the embodiment, the unit optical shape 121 may be a polygonal column shape formed by a plurality of three or more surfaces.

(7) In the embodiment, the screen 10 includes the base material layer 11 and the protective layer 15 when the first optical shape layer 12 and the second optical shape layer 14 have sufficient thickness, rigidity, and the like. It is good also as a form which is not provided with either one.
Moreover, in each embodiment, the screen 10 is good also considering the at least one of the base material layer 11 and the protective layer 15 as a plate-shaped member which has light transmittances, such as a glass plate. At this time, the first optical shape layer 12 or the like may be bonded to a glass plate or the like via an adhesive layer or the like.

(8) In the embodiment, the video source LS may be a video source that projects video light having a P-wave polarization component, for example.
The position and angle of the image source LS are set so that the image light is projected onto the screen 10 at the incident angle θa. At this time, the incident angle θa is (θb−10) ° or more when the incident angle (Brewster angle) at which the reflectance of the image light (P wave) projected onto the screen 10 is zero is θb (°). The range is set to 85 ° or less. For example, when the incident angle θb at which the reflectance of the image light projected onto the screen 10 is zero is 60 °, the incident angle θa of the image light is set in the range of 50 to 85 °.
Thus, by using the video source LS that projects video light having a P-wave polarization component, even when the incident angle θa to the screen 10 is large, specular reflection on the surface of the screen 10 can be suppressed. The degree of freedom in designing the projection system, such as the installation position of the video source LS, can be increased. Further, by using such an image source LS, the reflection of image light on the screen surface when entering the screen 10 can be reduced, and the brightness and clearness of the image can be improved.
The angle θb (Brewster angle) varies depending on the material of the surface of the screen 10 on which the image light is projected.
Moreover, in the case of such a form, as the base material layer 11 and the protective layer 15, the TAC sheet-like member is suitable.

(9) In the embodiment, the video display device 1 has been described as being applied to a show window such as a store. However, the present invention is not limited to this. Applicable.

  In addition, although embodiment and a deformation | transformation form can also be used in combination as appropriate, detailed description is abbreviate | omitted. In addition, the present invention is not limited to the embodiment described above.

DESCRIPTION OF SYMBOLS 1 Image display apparatus 10 Screen 11 Base material layer 12 1st optical shape layer 121 Unit optical shape 121a 1st slope 121b 2nd slope 13 Reflection layer 131 1st reflection layer part 132 2nd reflection layer part 14 2nd optical shape layer 15 Protective layer LS Video source

Claims (8)

A screen that reflects image light projected from an image source and displays images on both sides,
A first surface on which image light is incident and a second surface opposite to the first surface are both surfaces,
A plurality of elements are arranged in a predetermined direction along the screen surface in the screen, extend in a band shape in a direction crossing the arrangement direction, reflect a part of incident light toward the first surface side, A first reflective layer that transmits at least part of the light to the second surface side;
A second reflective layer portion that is provided between the adjacent first reflective layer portions and reflects at least part of the light transmitted through the first reflective layer portion to the second surface side;
With
In a cross section parallel to the arrangement direction of the first reflection layer portion and the second reflection layer portion and the thickness direction of the screen,
The first reflective layer portion forms an angle θ1 with respect to a plane parallel to the screen surface,
The second reflective layer portion has an angle θ2 larger than an angle θ1 with respect to a plane parallel to the screen surface,
The first reflective layer portion and the second reflective layer portion are rough surfaces having irregular irregular shapes on the surface, and a dielectric in which two dielectric films having different refractive indexes are alternately stacked in the thickness direction. Formed by multilayer film,
Of the first reflective layer part and the second reflective layer part, at least the second surface side in the thickness direction of the second reflective layer part is one of the two dielectric films having different refractive indexes. A low refractive index dielectric film having a lower refractive index than the dielectric film is located, and the thickness thereof is 0.5 μm or more,
A screen characterized by. The screen of claim 1,
In the thickness direction of the screen, the layer adjacent to the second surface side of the first reflective layer portion and the second reflective layer portion has a refractive index of 1.56 to 1.7,
The low refractive index dielectric film has a refractive index of 1.33 to 1.47,
A screen characterized by. The screen according to claim 1 or 2,
The thickness of the low refractive index dielectric film positioned at the most on the second surface side in the thickness direction of the second reflective layer portion is 3.0 μm or less;
A screen characterized by. In the screen according to any one of claims 1 to 3,
In a cross section parallel to the arrangement direction of the second reflective layer portions and the thickness direction of the screen, an angle φ between the second reflective layer portion and a direction orthogonal to the screen surface is 0 <φ <2 × (θ1) Meeting,
A screen characterized by. In the screen according to any one of claims 1 to 4,
An optical shape layer in which a plurality of unit optical shapes each having a first surface on which image light is incident and a second surface facing the first surface are arranged on the surface on the second surface side;
The first reflective layer portion is provided on at least a part of the first surface;
The second reflective layer portion is provided on at least a part of the second surface;
A screen characterized by. The screen according to claim 5, wherein
The unit optical shape is a partial shape of a perfect circle when viewed from the front direction of the screen, and a plurality of concentric circles are arranged.
A screen characterized by. The screen according to any one of claims 1 to 6,
Not having a light diffusion layer containing diffusing particles having a function of diffusing light;
A screen characterized by. A screen according to any one of claims 1 to 7,
An image source for projecting image light onto the screen;
A video display device comprising:

Images