JP2017134315A - Screen and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen that is highly transparent and capable of displaying images on both sides thereof, and to provide an image display device having the same.SOLUTION: A screen 10 includes: a first optical shape layer 12 having a plurality of unit optical shapes 121 arranged on a rear surface thereof, each unit optical shape comprising a first sloped surface 121a that directly receives image light and a second sloped surface 121b facing the first sloped surface, the first sloped surface 121a and the second sloped surface 121b having fine rugged patterns formed thereon; a semi-transmissive reflective layer 13 formed on the unit optical shapes 121 and configured to reflect a portion of the incident light and transmit the rest; and a second optical shape layer 14 laminated to fill troughs between the unit optical shapes 121. A reflective surface of the reflective layer 13 interfacing with the respective unit optical shape 121 has a fine rugged pattern thereon. The first sloped surface 121a and the second sloped surface 121b are at angles θ1, θ2 (θ2>θ1) with a plane parallel to a screen surface, respectively, and an angle φ between the second sloped surface 121b and a direction normal to the screen surface satisfies 0<φ<2×(θ1).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a reflective screen that reflects and displays video light, and a video display device including the same.

  Conventionally, various reflection screens that reflect and display image light projected from an image source have been developed (see, for example, Patent Document 1). In particular, the transflective reflective screen can be used as a reflective screen that allows a good image to be visually confirmed when used by being attached to a highly translucent member such as a glass plate. There is an advantage that the scenery on the other side of the screen can be seen through when not in use, etc. when not projecting.

Japanese Patent Laid-Open No. 9-11003

However, when such a transflective reflective screen is provided with a diffusion layer containing diffusing particles or the like, the scenery on the other side of the screen may be observed as whitish and blurred, resulting in deterioration in design. Therefore, improvement of transparency has been an issue.
There is also a demand for displaying images on both the image source side and the back side of the transflective screen while having transparency.
Furthermore, it is always required to reduce the thickness of various screens and display good images with high contrast.

  Patent Document 1 described above proposes a screen that can be used for both a transmissive type and a reflective type, and can transmit light from the back side. However, this Patent Document 1 does not disclose any measures for improving the transparency. Further, Patent Document 1 does not disclose that video is displayed on both sides of the screen by video light projected from one direction.

  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.
The invention of claim 1 is a reflective screen that reflects the image light projected from the image source and displays the image on both sides, the first surface (121a, 221a) on which the image light is directly incident, A plurality of unit optical shapes each having a second surface (121b, 221b) opposite to the first surface and a fine uneven shape on the first surface and the second surface are arranged on the rear surface. A first optical shape layer (12, 22), a semi-transmissive reflective layer that reflects part of incident light and transmits others; a first reflective layer portion formed on the first surface; A reflection layer (13) provided with a second reflection layer portion formed on the second surface, and having light transmission properties, the unit optics on the opposite side of the reflection layer from the first optical shape layer. A second optical shape layer (14) laminated to fill valleys between shapes, and the reflective layer The reflective surface serving as the interface with the coordinate optical shape has a concavo-convex shape corresponding to the concavo-convex shape, and the first surface forms an angle θ1 with respect to a plane parallel to the screen surface, and the second surface Forms an angle θ2 larger than an angle θ1 with respect to a plane parallel to the screen surface, and an angle φ between the second surface and a direction orthogonal to the screen surface satisfies 0 <φ <2 × (θ1). A screen (10, 20) characterized by filling.
According to a second aspect of the present invention, in the screen according to the first aspect, the second reflective layer portion (132) has a higher reflectance than the first reflective layer portion (131). 10, 20).
The invention according to claim 3 is the screen according to claim 1 or 2, wherein the angle φ is equal to or substantially equal to the angle θ1.
According to a fourth aspect of the present invention, in the screen according to any one of the first to third aspects, the light passes through the first reflective layer portion (131) and enters the second reflective layer portion (132). The screen (10, 20) is characterized in that the region (B) through which the transmitted light passes through the first reflective layer portion has a higher transmittance than the other regions of the first reflective layer portion.
According to a fifth aspect of the present invention, in the screen according to any one of the first to fourth aspects, the refractive index of the second optical shape layer (14) is that of the first optical shape layer (12). A screen (10, 20) characterized by being equal to or substantially equal to the refractive index.
According to a sixth aspect of the present invention, in the screen according to any one of the first to fifth aspects, a specular region in which the uneven shape is not formed per unit area of the first reflective layer portion (131). The screen (10, 20) is characterized in that the percentage occupied by is 5% or less.
The invention according to claim 7 is the screen according to any one of claims 1 to 6, wherein the screen (10, 20) is characterized by not comprising a diffusion layer containing diffusion particles. is there.
According to an eighth aspect of the present invention, in the screen according to any one of the first to seventh aspects, the unit optical shape (121, 221) of the first optical shape layer (12, 22) is formed. The screen (10, 20) is characterized in that a substrate layer (11) serving as a substrate for forming the first optical shape layer is provided on the surface opposite to the surface.
The invention of claim 9 is an image display comprising the screen (10, 20) according to any one of claims 1 to 8 and an image source (LS) for projecting image light onto the screen. Device (1).

  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 which shows the video display apparatus 1 of 1st Embodiment. It is a figure which shows the layer structure of the screen 10 of 1st Embodiment. It is the figure which looked at the 1st optical shape layer 12 of a 1st embodiment from the back side (-Z side). It is a figure explaining the unit optical shape 121 of 1st Embodiment. It is a figure which shows the mode of the image light and external light on the screen 10 of 1st Embodiment. It is a figure explaining the screen 20 of 2nd Embodiment. It is a figure which shows the video display apparatus 1A of a deformation | transformation form. It is a figure explaining the relationship between 1/2 angle | corner (alpha), incident angle (theta) a of image light, and angle (theta) 1 of the 1st slope 121a.

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 (substantially equal state).
In the present specification, numerical values such as dimensions and material names of each member to be described 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.

(First embodiment)
FIG. 1 is a diagram illustrating a video display device 1 according to the first 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.
In the present embodiment, as an example, the video display device 1 is applied to a shop show window, and the screen 10 is fixed to the glass of the show window.

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 (left-right direction) of the screen 10 is the X direction, the vertical direction (up-down direction) is the Y direction, and the thickness direction of the screen 10 is the Z direction. The screen of the screen 10 is parallel to the XY plane, and the thickness direction (Z direction) of the screen 10 is orthogonal to the screen 10.
Further, the direction toward the right side in the horizontal direction when viewed from the observer O1 positioned in the front direction on the image source side of the screen 10 is the + X direction, the direction toward the upper side in the vertical direction is the + Y direction, and the back side (back side) in the thickness direction. ) To the video source side is defined as + 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 enters the screen 10.

The screen 10 reflects a part of the image light L projected by the image source LS toward the observer O1 side located on the image source side (+ Z side) and displays an image, and one of the other image lights. Is a screen that displays an image by being emitted toward an observer O2 (see FIG. 5) positioned on the back side (back side), and beyond the screen 10 when not using image light. This is a transflective reflective screen that allows you to observe the side scenery.
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 when viewed from the viewer O1 side on the video source side (+ Z side).
The screen 10 has a large screen with a diagonal size of about 80 to 100 inches, and the aspect ratio of the screen is 16: 9. However, the present invention is not limited to this. For example, the size may be about 40 inches or less, and the size and shape can be appropriately selected according to the purpose of use and the use environment.

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, as shown in FIG. 1, the screen 10 of this embodiment is joined (or partially fixed) to the support plate 50 integrally on the back side of the screen 10 via a light-transmitting joining layer 51, thereby improving the flatness of the screen. Is maintained.
The support plate 50 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 support plate 50 of this embodiment is a window glass of a show window such as a store. 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 first 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. In FIG. 2, the support plate 50 and the like are omitted for easy understanding.
FIG. 3 is a view of the first optical shape layer 12 of the first embodiment 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 according to the first 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.
Moreover, the base material layer 11 can change the thickness according to screen sizes etc., and the thickness in this embodiment is about 100 micrometers.

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, a plurality of unit optical shapes 121 are arranged concentrically around a point C located outside the screen (display area) of the screen 10. That is, the first optical shape layer 12 has a circular Fresnel lens shape on the back side.
The circular Fresnel lens shape of the first optical shape layer 12 is a circular Fresnel lens shape having a so-called offset structure with the point C as the center (Fresnel center). Therefore, as shown in FIG. 3, when the first optical shape layer 12 is viewed from the back side in the normal direction of the screen surface, a unit optical shape (unit lens) 121 having a partial shape (arc shape) of a perfect circle is formed. Observed as multiple arrays.

2 and 4, the unit optical shape 121 is parallel to the direction orthogonal to the screen surface (Z direction), and the cross-sectional shape in the cross section parallel to the arrangement direction of the unit optical shapes 121 is substantially triangular. Shape.
The unit optical shape 121 is convex on the back side, and has a first inclined surface (lens surface) 121a on which image light is incident and a second inclined surface (non-lens surface) 121b facing the first inclined surface (lens surface) 121b.
In one unit optical shape 121, the second inclined surface 121b is positioned below the first inclined surface 121a with the apex t interposed therebetween.
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 first inclined surface 121a and the second inclined surface 121b of the unit optical shape 121 have a fine uneven shape.

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 221. .
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 may be changed along the arrangement direction of the unit optical shapes 121, and the angles θ1 and θ2 may be changed.

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.
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.

FIG. 8 is a diagram for explaining the relationship between the ½ angle α, the incident angle θa of the image light, and the angle θ1 of the first inclined surface 121a. FIG. 8 shows a further enlarged section of the screen 10 shown in FIG. 2, and the structure in the screen 10 is simplified and the base material layer 11 and the protective layer 15 are omitted for easy understanding. ing. Further, regarding the angles α and θa, the upper side in the vertical direction of the screen is shown as plus and the lower side is shown as minus with respect to the direction orthogonal to the screen surface.
Here, with respect to the angle K of the peak luminance of light (reflected light) incident on the first reflecting layer portion 131 of the first inclined surface 121a and diffusely reflected and emitted from the screen 10, the vertical direction of the screen (unit in FIG. 8). In the arrangement direction of the optical shape 121), the angles at which the luminance is halved are K1 and K2, and the angle change amount from the peak luminance angle K to the angles K1 and K2 at which the luminance is ½ is + α1 (where When K + α1 = K1) and −α2 (K−α2 = K2), the average value of the absolute value of the angle change amount from the peak luminance to the luminance becomes ½ is α (hereinafter referred to as ½ angle). a).

The angle θ1 of the first slope 121a is an angle K at which the image light L is reflected most efficiently to the observer O1 positioned in the front direction on the image source side of the screen 10, that is, the peak brightness of the reflected light. Is designed based on the refractive index of each layer and the like so that the angle becomes 0 °. Further, the range from −α to + α is a range in which it is assumed that an observer located in front of the screen observes the video satisfactorily.
Here, at a certain point in the vertical direction of the screen (the arrangement direction of the unit optical shapes 121 in FIG. 8), the image light L is incident from below the screen 10 at an incident angle θa, and the first optical shape layer 12 having a refractive index n is passed through the first optical shape layer 12. Advancing and entering the first inclined surface 121a that makes an angle θ1 with respect to the screen surface, reflected by the reflective layer 13, and emitted from the screen 10 in a direction perpendicular to the screen surface (exit angle 0 °), the angle θ1 is It is expressed by the following formula.
θ1 = 1/2 × arcsin ((sin (θa)) / n) (Formula 1)

When the image light L is projected from the image source LS onto the screen 10 and reflected by the screen 10 and the image is displayed as a reflective screen, the light source of the image source LS that projects the image light L is reflected, and the image contrast is increased. There may be a problem of degradation. This reflection of the image source is mainly caused by the image light reflected by the surface of the screen reaching the observer O1.
In order to prevent such reflection of the image source, the screen 10 is positioned outside the angle range (−α to + α) that is a range in which the observer O1 mainly observes the image favorably on the surface of the screen 10. It is preferable that the image light reflected on the surface of the light travels. When a part Lr of the image light L incident at the incident angle θa is reflected by the surface of the screen 10, the reflection angle is θa. Therefore, α <θa is preferable in order to prevent the reflection of the image source.

Therefore, from the above (Formula 1), in the vertical direction of the screen (the arrangement direction of the unit optical shapes 121), the ½ angle α is at least a partial region of the screen 10 with respect to the angle θ1 of the first inclined surface 121a. In (for example, the center of the screen), it is preferable to satisfy the following Expression 2.
α <arcsin (n × sin (2 × (θ1))) (Expression 2)
In order to prevent the reflection of the image source, it is more preferable that the half angle α satisfies the above formula 2 over the entire area of the screen 10 with respect to the angle θ1 of the first slope 121a.
When the angle θ1 is a form satisfying the above formula 2 with respect to the half angle α, the direction in which the light reflected by the surface of the screen 10 mainly enters when entering the screen 10 (the direction of + θa) is reflected. The image light reflected by the layer 13 (first reflective layer portion 131) is outside the angle range (−α to + α) mainly emitted from the screen 10 and traveling. Thereby, on the image source side (+ Z side), it is possible to reduce the reflection of the image source LS in the range (angle −α to + α) in which the observer O1 visually recognizes the image and display a good image with high contrast. it can.

The half angle α preferably satisfies 5 ° ≦ α ≦ 45 °.
If α <5 °, the viewing angle for displaying a good image for the observer O1 becomes too narrow and the image becomes difficult to see, which is not preferable. Further, when α <5 °, the specular reflection component in the reflected light increases, and the reflection of the image source occurs, which is not preferable.
When α> 45 °, the viewing angle for displaying a good image for the observer O1 becomes wide, but the brightness of the image decreases, the blur of the image increases, The contrast of the image is lowered by reflection, which is not preferable.
Accordingly, the ½ angle α is preferably in the above range.

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 is a so-called half mirror that reflects a part of incident light and transmits the other part. Therefore, the reflective layer 13 has a function of diffusing and reflecting a part of incident light by the fine uneven shape of the reflecting surface and transmitting other light that does not reflect without diffusing.

As described above, the first inclined surface 121a and the second inclined surface 121b are formed with fine uneven shapes, and the reflective layer 13 is formed following the fine uneven shapes. In addition, the thickness of the reflective layer 13 is sufficiently thinner than the fine irregularities. Therefore, the reflection surface of the reflection layer 13 (the surface of the reflection layer 13 on the first optical shape layer 12 side) and the surface of the second optical shape layer 14 side are mat surfaces having fine irregularities.
The surface roughness of the reflecting surface of the reflecting layer 13 (that is, the surface roughness of the first inclined surface 121a) is such that the arithmetic average roughness Ra is about 0.15 to 0.3 μm. It is preferable from the viewpoint of displaying. The arithmetic average roughness Ra, which is the surface roughness of the reflecting surface of the reflecting layer 13 (that is, the surface roughness of the first inclined surface 121a), may be appropriately selected according to the desired optical performance and the like.

The ratio of the reflectance and transmittance of the reflective layer 13 can be set as appropriate in accordance with the desired optical performance. However, while reflecting the image light well, light other than the image light (for example, from outside such as sunlight) From the viewpoint of transmitting light well, it is desirable that the transmittance is 30 to 80% and the reflectance is 5 to 60%.
Here, the reflective layer 13 has 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 first reflective layer portion 131 and the second reflective layer portion 132 have different reflectances, and the reflectance of the second reflective layer portion 132 is larger than the reflectance of the first reflective layer portion 131.
In the present embodiment, the first reflective layer portion 131 has a transmittance of about 60% and a reflectance of about 30%, and the second reflective layer portion 132 has a transmittance of about 30% and a reflectance of about 60%. It is.

Further, in the first inclined surface 121a, a region that is not a rough surface, that is, a region where a fine uneven shape is not formed, and the reflection surface of the first reflection layer 131 has a mirror surface, and incident video light is a mirror surface. The reflecting mirror surface area is 5% or less per unit area of the first reflecting layer portion 131, which is necessary for sufficiently diffusing video light and obtaining a good viewing angle, and is 0%. Ideal.
If the mirror surface area that is not a rough surface exceeds 5% per unit area of the first reflective layer 131, a bright line is generated due to the component of the image light that is reflected without being diffused and reaches the image source side, and the viewing angle is increased. It is not preferable because it decreases.

The reflective layer 13 is formed of a metal having high light reflectivity, such as aluminum, silver, nickel, etc., and the thickness thereof is about several tens of millimeters. The first reflective layer portion 131 and the second reflective layer portion 132 have different thicknesses, and the second reflective layer portion 132 is formed thicker than the first reflective layer portion 131. The reflective layer 13 of this embodiment is formed by evaporating aluminum.
The reflective layer 13 is not limited to this, and may be formed, for example, by sputtering a metal with high light reflectivity, transferring a metal foil, or applying a paint containing a metal thin film, For example, it may be formed by depositing a dielectric multilayer film. At this time, the second reflective layer portion 132 is formed to have a higher reflectance than the first reflective layer portion 131.

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 reflection layer 131 is diffused by the fine uneven shape of the reflection surface.
Further, a part Lc of the video light La 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. 121b, reflected by the second reflective layer 132, and emitted in a direction in which an image can be viewed by an observer O2 (see FIG. 5 described later) positioned in the front direction on the back side (-Z side) of the screen 10. To do. At this time, the image light Ld reflected by the second reflecting layer portion 132 is diffused by the fine uneven shape of the reflecting surface.

The video light Ld that has entered the region B and has passed through the first reflective layer portion 131 is incident on the second inclined surface 121b, reflected by the second reflective layer portion 132, and emitted to the viewer O2 side located on the back side. For this purpose, it is preferable that the angle φ formed with respect to the direction orthogonal to the screen surface of the second inclined surface 121b is 0 <φ <2 × (θ1), and φ is substantially equal to θ1 (so that it can be regarded as equal). More preferably, the state having an error is more preferably equal to θ1.
When this 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.

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. The second optical shape layer 14 is provided to flatten the back side (−Z side) surface of the first optical shape layer 12, and is formed so as to fill valleys between the unit optical shapes 121. Yes. Accordingly, the image source side (+ Z side) surface 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, and the protective layer 15 and the like can be easily laminated on the back surface of the first optical shape layer 12 of the screen 10. Also, joining to the support plate 50 and the like is facilitated.
The refractive index of the second optical shape layer 14 is preferably equal to or substantially equal to the refractive index of the first optical shape layer 22 (the difference in refractive index is small enough to be regarded as equal). It is preferable to use the same ultraviolet curable resin as the first optical shape layer 12 described above. The refractive index of the second optical shape layer 14 of the present embodiment is equal to the refractive index of the first optical shape layer 12.

The protective layer 15 is a light-transmitting layer formed 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 made of a resinous sheet-like member having high light transmittance. 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 this embodiment does not include a light diffusion layer containing a diffusing material such as particles having a diffusing action, and the diffusing action is caused by fine irregularities on the reflecting surface of the reflecting layer 13. Only the shape.

The screen 10 is formed 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, a fine uneven shape is formed on the surface forming the first inclined surface 121a and the second inclined surface 121b of the mold for forming the unit optical shape 121. This fine concavo-convex shape can be formed by repeating plating under different conditions twice or more on the surface forming the first inclined surface 121a and the second inclined surface 121b of the mold or performing an etching process.
After the first optical shape layer 12 is formed on one surface of the base material layer 11, the reflective layer 13 is formed on the first slope 121a and the second slope 121b by vapor deposition or the like. At this time, the deposition direction is set so that the reflectance of the second reflective layer portion 132 formed on the second slope 121b is larger than the reflectance of the first reflective layer portion 131 formed on the first slope 121a. The reflective layer 13 is formed while adjusting the thickness of the first reflective layer 131 and the second reflective layer 132 by changing the thickness.

After that, an ultraviolet curable resin is applied from above the reflective layer 13 so as to fill the valleys between the unit optical shapes 121 and form a flat surface, and the protective layer 15 is laminated to cure the ultraviolet curable resin. The second optical shape 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. When the base material layer 11 and the protective layer 15 are formed in a web shape, the screen 10 in a state before cutting can be continuously manufactured, which can improve the production efficiency of the screen 10 and reduce the production cost. it can.

  Further, for example, as a method of forming rough surfaces on the first inclined surface 121a and the second inclined surface 121b, diffusing particles or the like are applied on the first inclined surface 121a and the second inclined surface 121b, and the reflective layer 13 is formed thereon. A method of performing blasting on the first slope 121a and the second slope 121b after forming the first optical shape layer 12 is known. However, when the reflective surface of the reflective layer 13 is roughened by such a manufacturing method, there are large variations in diffusion characteristics, quality, and the like on the individual screens 10, and stable production cannot be performed. On the other hand, as described above, by forming the fine concavo-convex shapes of the first inclined surface 121a and the second inclined surface 121b of the unit optical shape 121 with a molding die, a large number of first optical shape layers 12 and screens 10 are formed. Also in the case of manufacturing, there is an advantage that quality can be stably manufactured with little variation in quality.

FIG. 5 is a diagram illustrating a state of image light and external light on the screen 10 of the first embodiment. In FIG. 5, a part of a cross section in a cross section parallel to the arrangement direction (Y direction) of the unit optical shapes 121 and the thickness direction (Z direction) of the screen is shown enlarged. Further, in FIG. 5, for easy understanding, it is assumed that there is no refractive index difference at the interface of each layer in the screen 10.
Part of the image light L2 projected from the image source LS located below the screen 10 and incident on the screen 10 is reflected by the surface of the screen 10 and travels upward. Accordingly, the observer O1 positioned in the front direction on the image source side of the screen 10 does not reach. Further, a part of the image light L3 enters 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 exits to the viewer O1 side.

The other image light L4 that has not been reflected among the image light incident on the first inclined surface 121a is transmitted through the reflective layer 13 (first reflective layer portion 131) and from the back side (−Z side) of the screen 10 to above the screen. To exit. Therefore, the video light L4 does not reach the observer O2 located in the front direction of the screen 10 on the back side.
In addition, the image light L5 incident on the region B near the point v serving as the valley bottom of the first slope 121a is partially reflected by the first reflection layer 131 and emitted toward the observer O1. In addition, a part of the image light L7 out of the image light L5 is diffused and reflected by the second reflection layer portion 132 of the second inclined surface 121b that passes through the reflection layer 13 (first reflection layer portion 131) and is adjacent thereto. The light is emitted to the observer O2 side positioned in the front direction of the screen on the back side. With this video light L7, the back side observer O2 can also visually recognize the video.
In the present embodiment, the image lights L1 and L5 are 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. Therefore, the image light does not directly enter the second inclined surface 121b.

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, a part of the external light G <b> 2 and G <b> 6 out of the external light G <b> 1 and G <b> 5 incident on the screen 10 is reflected by the surface of the screen 10 and travels downward to the screen 10. Also, some of the external lights G3 and G7 are reflected by the reflection layer 13, and are emitted above the screen on the video source side and below the screen 10 on the back side, respectively. Further, 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 (−Z side) and the video source side (+ Z 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 does not contain a diffusing material containing diffusing particles, the external lights G9 and G10 transmitted through the screen 10 are not 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.

Here, in a conventional transflective reflective screen with a diffusing layer containing diffusing particles, external light is also diffused by the diffusing particles, so the scenery on the other side of the screen is blurred or whitened. Or the contrast of the image is lowered. In addition, since the image light is diffused twice before and after reflection by the reflection layer, there is a problem that a good viewing angle can be obtained while the brightness is lowered and the resolution of the image is lowered.
However, since the screen 10 of this embodiment has no diffusing action except that the reflective surface of the reflective layer 13 is rough, the image light is diffused only when reflected by the reflective layer 13. Moreover, in the screen 10 of this embodiment, only the light reflected by the reflective layer 13 is diffused, and the transmitted light is not 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 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. A good video 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, the scenery on the other side (+ Z side) of the screen 10 can be seen well 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 transmitted light and has high transparency. Therefore, even when image light is projected on the screen 10, the observers O1 and O2 A part of the scenery on the other side (back side, video source side) of the screen 10 can be visually recognized.
Further, according to the present embodiment, the first optical shape layer 12 has a point C serving as a Fresnel center located outside the display area and on the image source LS side, and has a circular Fresnel lens shape having a so-called 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 a good image with high surface uniformity of brightness Can be displayed.

(Second Embodiment)
FIG. 6 is a diagram illustrating the screen 20 according to the second embodiment. FIG. 6A is a view of the first optical shape layer 22 of the screen 20 as viewed from the back side (−Z side). For easy understanding, the reflective layer 13, the second optical shape layer 14, The protective layer 15 and the like are omitted. FIG. 6B shows an enlarged part of the cross section of the screen 20 of the second embodiment corresponding to the cross section of the screen 10 of the first embodiment shown in FIG.
The screen 20 shown in the second embodiment has the same form as that of the first embodiment, except that the unit optical shape 221 of the first optical shape layer 22 is different. Therefore, parts having the same functions as those of the first embodiment described above are denoted by the same reference numerals or the same reference numerals at the end thereof, and repeated descriptions are appropriately omitted.
The screen 20 of the second embodiment can be used in place of the screen 10 in the video display device 1 of the first embodiment described above.

The screen 20 includes a base material layer 11, a first optical shape layer 22, a reflective layer 13, a second optical shape layer 14, and a protective layer 15.
The first optical shape layer 22 is provided with a plurality of unit optical shapes 221 arranged on the back side (−Z side) surface.
The unit optical shapes 221 extend in the left-right direction (X direction) of the screen 10 and are arranged in a plurality along the vertical direction of the screen (Y direction). The unit optical shape 221 is a so-called prism shape in which the cross-sectional shape in a cross section parallel to the thickness direction (Z direction) of the screen 10 and parallel to the arrangement direction (Y direction) of the unit optical shapes 121 is triangular. .

The unit optical shape 221 has a first inclined surface 221a on which image light is directly incident and a second inclined surface 221b facing the first inclined surface 221a. In one unit optical shape 221, the second inclined surface 221b is located on the lower side (−Y side) than the first inclined surface 221a across the vertex t.
In the present embodiment, as shown in FIG. 6, an example in which the angles θ <b> 1 and θ <b> 2, the arrangement pitch P, and the like are constant is shown. However, the present invention is not limited thereto, and these angles and dimensions may include 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 pixel (pixel) of the image source LS, the screen It may be set as appropriate according to the screen size of 10, the refractive index of each layer and the like. For example, these angles and dimensions may change gradually or stepwise along the arrangement direction of the unit optical shapes 121.

In the unit optical shape 221, as shown in FIG. 6B, the angle formed by the first inclined surface 221a and the surface parallel to the screen surface is θ1, and the angle formed by the second inclined surface 221b and the surface parallel to the screen surface. Is θ2. The apex angle of the unit optical shape 121 is θ3. At this time, the angles θ1 and θ2 satisfy the relationship θ2> θ1.
In addition, the second inclined surface 121b forms an angle φ with respect to the direction orthogonal to the screen surface. This angle φ is preferably 0 <φ <2 × (θ1), more preferably φ is substantially equal to θ1 (a state having an error that can be regarded as equal), and φ is further equal to θ1. preferable. When the angle φ is equal to the angle θ1, the apex angle θ3 is equal to 90 °.
Further, the angle θ1 satisfies the above-described expression 2 with respect to the half angle α.

Also in the present embodiment, the reflectance of the second reflective layer portion 132 formed on the second slope 221b in the reflective layer 13 is the reflectance of the first reflective layer portion 131 formed on the first slope 221a. Bigger than.
Therefore, a part of the image light incident on the region B of the first slope 221a is transmitted through the first reflection layer 131, and reflected by the second reflection layer 132 of the second slope 221b, and the back side (−Z (Side) toward the observer O2 side. Thereby, the observer O2 who exists in the back side can visually recognize an image | video.

Therefore, according to the present embodiment, as in the first embodiment described above, it is possible to provide a transflective screen and display device that are highly transparent and capable of displaying good images on both sides.
Further, in this embodiment, the unit optical shapes 221 are arranged in the vertical direction of the screen with the horizontal direction of the screen being the longitudinal direction, and the first optical shape layer 22 and the screen 20 can be easily manufactured. 20 can be easily manufactured.

(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 each embodiment, the transmittance of the first reflective layer portion 131 may be larger than that of the second reflective layer portion 132.
Moreover, in each embodiment, the area | region B of the 1st reflection layer part 131 may have a reflectance smaller than the other area | region of 1st slope 121a, 221a, and a transmittance | permeability may be high.
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 each embodiment, the screens 10 and 20 may be configured such that the reflective layer 13 is not provided. In this case, from the viewpoint of efficiently reflecting the image light toward the observer O1 side and the observer O2 side, the second slope 121b between the first slope 121a and the second optical shape layer 14 of the first optical shape layer 12 and It is necessary to provide one or more layers having a refractive index different from the refractive index of the first optical shape layer 12 (for example, an air layer or a layer formed of an organic multilayer film) between the second optical shape layer 14 and the second optical shape layer 14.

(3) In each embodiment, a hard coat layer for the purpose of preventing scratches may be provided on the image source side (+ Z side) surfaces of the screens 10 and 20. The hard coat layer is formed by, for example, applying an ultraviolet curable resin (for example, urethane acrylate) having a hard coat function to the image source side surface of the screens 10 and 20 (the image source side surface of the base material layer 11). It is formed by forming.
Further, not only the hard coat layer but also a layer having necessary functions as appropriate, such as an antireflection function, an ultraviolet absorption function, an antifouling function, an antistatic function, etc., depending on the use environment or purpose of use of the screens 10 and 20. One or more 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.
Such a hard coat layer and the like may be provided on the back side (−Z side) of the screens 10 and 20 depending on the environment in which the screens 10 and 20 are used.

(4) In each 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 screens 10 and 20 and is located on the lower side in the vertical direction. , 20 may be arranged so as to project the image light from the oblique direction light in the horizontal direction of the screen with respect to the screens 10, 20.
FIG. 7 is a diagram showing a modified image display apparatus 1A. FIG. 7 shows an example using the screen 20 shown in the second embodiment.
As shown in FIG. 7, for example, when the video source LS is arranged below the left side of the screen 10 in the left-right direction (−X side), the unit optical shape 221 has the arrangement direction and the longitudinal direction of the video source LS. According to the position, the screen is inclined with respect to the vertical direction of the screen (Y direction) and the horizontal direction of the screen (X direction). By adopting such a form, the position of the video source LS and the like can be freely set.
Even when the first optical shape layer 12 has a circular Fresnel lens shape like the screen 10 shown in the first embodiment, the arrangement direction of the unit optical shapes 221 is inclined according to the position of the image source LS. Thus, such a modification can be applied.

(5) In each embodiment, the unit optical shapes 121 and 221 are examples in which the first inclined surfaces 121a and 221a and the second inclined surfaces 121b and 221b are formed as flat surfaces. It is good also as a form with which the plane was combined, and it is good also as a folded surface shape.
In each embodiment, unit optical shape 121, 221 is good also as a polygonal column shape formed by a plurality of three or more surfaces.

(6) In each embodiment, when the first optical shape layers 12 and 22 and the second optical shape layer 14 have sufficient thickness, rigidity, etc., the screens 10 and 20 It is good also as a form which is not provided with the protective layer 15, and is good also as a form which is not provided with either one.
Moreover, in each embodiment, the screens 10 and 20 are 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.

(7) In each 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 screens 10 and 20 at the incident angle θa. At this time, when the incident angle (Brewster angle) at which the reflectance of the image light (P wave) projected onto the screens 10 and 20 is zero is θb (°), the incident angle θa is (θb-10). It is set in the range of not less than 85 ° and not more than 85 °. For example, when the incident angle θb at which the reflectance of the image light projected onto the screens 10 and 20 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 image source LS that projects image light having a P-wave polarization component, even when the incident angle θa to the screens 10 and 20 is large, specular reflection on the surfaces of the screens 10 and 20 is suppressed. It is possible to increase the degree of freedom in designing the projection system, such as the installation position of the image source LS. Further, by using such an image source LS, the reflection of the image light on the screen surface when entering the screens 10 and 20 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 surfaces of the screens 10 and 20 onto 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.

(8) In each embodiment, the video display device 1 has been shown as being disposed in a show window of a store or the like. However, the present invention is not limited to this. For example, the video display device 1 is used for video display in an indoor partition or an exhibition. Is also applicable.

  In addition, although this embodiment and modification can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited by the embodiments described above.

DESCRIPTION OF SYMBOLS 1 Image display apparatus 10,20 Screen 11 Base material layer 12,22 1st optical shape layer 121,221 Unit optical shape 121a, 221a 1st slope 121b, 221b 2nd slope 13 Reflective layer 131 1st reflective layer part 132 2nd Reflective layer portion 14 Second optical shape layer 15 Protective layer LS Image source

Claims (9)

A reflective screen that reflects image light projected from an image source and displays images on both sides,
A unit optical shape having a first surface on which image light is directly incident and a second surface opposite to the first surface, and the first surface and the second surface have fine irregular shapes, A plurality of first optical shape layers arranged on the surface of
A semi-transmissive reflective layer that reflects part of incident light and transmits others; a first reflective layer formed on the first surface; and a second reflective layer formed on the second surface A reflective layer comprising a reflective layer portion;
A second optical shape layer that has optical transparency and is laminated so as to fill valleys between the unit optical shapes on the opposite side of the reflective layer from the first optical shape layer;
With
The reflective surface serving as an interface with the unit optical shape of the reflective layer has a concavo-convex shape corresponding to the concavo-convex shape,
The first surface forms an angle θ1 with respect to a surface parallel to the screen surface;
The second surface forms an angle θ2 larger than the angle θ1 with respect to a surface parallel to the screen surface,
An angle φ formed by the second surface and a direction orthogonal to the screen surface satisfies 0 <φ <2 × (θ1).
A screen characterized by. The screen of claim 1,
The second reflective layer portion has a higher reflectance than the first reflective layer portion;
A screen characterized by. The screen according to claim 1 or 2,
The angle φ is equal to or substantially equal to the angle θ1;
A screen characterized by. In the screen according to any one of claims 1 to 3,
A region where light that is transmitted through the first reflective layer and incident on the second reflective layer is transmitted through the first reflective layer has higher transmittance than other regions of the first reflective layer. ,
A screen characterized by. In the screen according to any one of claims 1 to 4,
The refractive index of the second optical shape layer is equal to or substantially equal to the refractive index of the first optical shape layer;
A screen characterized by. In the screen according to any one of claims 1 to 5,
The proportion of the mirror region in which the uneven shape is not formed per unit area of the first reflective layer portion is 5% or less,
A screen characterized by. The screen according to any one of claims 1 to 6,
Not having a diffusion layer containing diffusing particles,
A screen characterized by. The screen according to any one of claims 1 to 7,
A substrate layer serving as a substrate for forming the first optical shape layer is provided on the surface of the first optical shape layer opposite to the surface on which the unit optical shape is formed;
A screen characterized by. A screen according to any one of claims 1 to 8,
An image source for projecting image light onto the screen;
A video display device comprising:

Images