WO2012161073A1

WO2012161073A1 - Display device

Info

Publication number: WO2012161073A1
Application number: PCT/JP2012/062632
Authority: WO
Inventors: 前川　聡; 杉山　貴
Original assignee: 独立行政法人情報通信研究機構; スタンレー電気株式会社
Priority date: 2011-05-25
Filing date: 2012-05-17
Publication date: 2012-11-29
Also published as: JP2012247458A

Abstract

[Problem] To provide a display device with which it is possible to easily view a real image which is formed by a real mirror video image forming optical assembly. [Solution] A display device comprises: a real mirror video image forming optical assembly, further comprising a semi-translucent base which separates a display-side space and an observed object-side space, said real mirror video image forming optical assembly forming a real image of an observed object in the display-side space via the base; and a semi-translucent plate which is positioned between the base and the real image of the observed object.

Description

Display device

The present invention relates to a display device that uses a real mirror image forming optical system to form a real image (real mirror image) of an object to be observed in the air.

A display device has been proposed in which a real image (real mirror image) of an object to be observed is formed in the air using a real mirror image forming optical system so that it can be seen by an observer (Patent Document 1). ,reference).

Such a display device includes an observation object arranged in a space opposite to the observer side, and a real mirror image imaging optical system that forms a real image of the observation object in the observer side space. It is a display device, and forms a real image of an object to be observed at a symmetrical position with respect to a symmetrical plane (element plane) of a real mirror image forming optical system.

WO2007-116639

In the method shown in Patent Document 1, an optical element that forms a real mirror image forming optical system (hereinafter referred to as a real mirror image optical element) is manufactured as a base such as a square, and a real mirror image is formed as shown in FIG. The optical element 5 is used by being incorporated in a display device in a state where the optical element 5 is fitted in the frame 8 that is one size larger. Therefore, the boundary BL between the real mirror image optical element 5 and the frame 8 is formed. When the observer observes the display device, he / she sees the frame, the real mirror image optical element, and the real mirror image formed in the space before the real mirror image optical element.

At this time, if the real mirror image is near the center of the real mirror image optical element, the observer can easily view it as an aerial image, but the real mirror image is near the end of the real mirror image optical element, that is, the frame. It is difficult to visually recognize the aerial image when it is in the vicinity of the boundary. As a result of repeating various experiments, it was found that it is difficult to visually recognize an aerial image when the boundary between the real mirror image, the real mirror image optical element, and the frame is observed at the same time and at a close position.

That is, the viewing angle range in which a real mirror image can be easily viewed as an aerial image is limited to a narrow range depending on the size of the real mirror image optical element and the size of the object to be observed.

Therefore, an object of the present invention is to provide a display device capable of easily viewing a real image formed by a real mirror image forming optical system.

The display device of the present invention has a semi-transparent base that partitions a display-side space that can be visually recognized by an observer and an object-side space in which the object is placed, and is provided in the display-side space via the base. It includes a real mirror image forming optical system for forming a real image of the object to be observed, and a translucent plate disposed between the base and the real image of the object to be observed.

In other words, the present invention has been conceived in order to widen the viewing angle range in which a real mirror image can be easily viewed as an aerial image. Specifically, a real image (real mirror image) of an object to be observed is observed by an observer. A real mirror image forming optical system that forms an image in a space on the side, and an object to form the real image disposed in a space opposite to the observer side of the real mirror image forming optical system; This is realized by the real mirror image forming optical system and the semi-transmissive plate disposed between the real images.

In other words, the viewing angle range is widened by making it difficult to see the boundary between the real mirror image optical element and the frame by the translucent plate disposed between the real mirror image forming optical system and the displayed real image. is there. That is, it is advantageous that the translucent plate is larger than the real mirror image forming optical system (actual mirror image optical element) because the boundary can be surely hidden and difficult to see.

In the present invention, as the translucent plate, for example, a translucent acrylic plate (plate) dyed with a black pigment, or an opaque portion printed on a transparent plate in the form of dots, the area ratio between the transparent portion and the opaque portion A plate that adjusts the transmittance can be used. Also, a thin metal film provided on a permeable substrate can be used. As an example of the translucent plate with a metal thin film, there is a so-called half mirror or the like in which a thin film is formed by vapor-depositing a metal such as chromium on a glass substrate. However, a simple half mirror is not preferable because there is reflection of an object on the observation side such as the face of the observer. In this case, the reflectivity of the observer-side metal thin film should be kept low. In the example of the translucent plate, the upper or lower portion of the chromium thin film can be used as a chromium oxide film to suppress reflection (look black). By adjusting how to suppress the reflection of the translucent plate and causing a slight reflection of an object on the viewer side, the boundary of the display device can be reliably hidden and can be difficult to see. It turns out that there is.

The transmissivity of the semi-transparent plate should be about 20% to about 80%, more preferably about 30% to about 60%, assuming that the transmittance when there is nothing is 100%. As a result of observation.

In the present invention, the anisotropic semipermeable plate is, for example, a semipermeable plate having a fine slit shape. The slits are parallel slits or mesh-shaped, and are inclined toward the observer side with respect to the element surface. By using an anisotropic semi-transmissive plate, light from other than the viewer direction cannot pass through the anisotropic semi-transmissive plate, and the boundary can be reliably hidden and difficult to see. And found that the aerial image can be brightened.

In the present invention, the real mirror image forming optical system is capable of observing a real mirror image of an object to be observed from a viewpoint from an oblique direction with respect to a symmetry plane (base). Can include a real mirror image-forming optical system composed of a two-surface corner reflector array. A two-surface corner reflector array is a set of a plurality of two-surface corner reflectors composed of two orthogonal mirror surfaces in a plane, and a common plane perpendicular to all the mirror surfaces is observed on the object to be observed. And an element surface which is a plane of symmetry with respect to the real image. This two-sided corner reflector array reflects the light emitted from the object to be observed once by the two mirror surfaces of each two-sided corner reflector and transmits the element surface to thereby change the element surface of the two-sided corner reflector array. As a symmetry plane, it has an action of forming an image of a real mirror image of the object to be observed at a plane symmetrical position of the object to be observed.

Here, considering the two-sided corner reflector array, in order to transmit light through the element surface while appropriately reflecting and bending the light at each two-sided corner reflector, the two-sided corner reflector is assumed to pass through the element surface. It can be considered that the inner wall of the optical hole is used as a mirror surface. However, such a two-sided corner reflector is conceptual and does not necessarily reflect the shape determined by the physical boundary, for example, optical holes are not independent of each other. It can be connected.

The structure of the two-sided corner reflector array is simply described by arranging a large number of mirror surfaces substantially perpendicular to the element surface on the element surface. The problem as a structure is how to support and fix the mirror surface to the element surface. As a more specific method of forming the mirror surface, for example, a two-sided corner reflector array is provided with a base that divides a predetermined space, and a single plane passing through the base is defined as an element surface. The corner reflector can be used as an optical hole assumed in a direction penetrating the element surface, and an inner wall of the hole formed in the base can be used as a mirror surface. The hole formed in the substrate only needs to be transparent so that light can be transmitted, and may be, for example, a vacuum filled with a transparent gas or liquid. Also, the shape of the hole may be any shape as long as the inner wall has a mirror surface that is not included in one or more coplanar surfaces to serve as a unit optical element, and the light reflected by the mirror surface can pass through the hole. It may be a complicated shape in which each hole is connected or a part thereof is missing. For example, an aspect in which individual mirror surfaces stand on the surface of the base can be understood as connecting holes formed in the base.

Alternatively, the double-sided corner reflector may use a cylindrical body formed of a solid such as transparent glass or resin as an optical hole. In addition, when each cylindrical body is formed of solid, these cylindrical bodies may be brought into close contact with each other and serve as a support member for the element, and project from the surface of the base as having a base. You may take the aspect which did. The cylindrical body also has one or more mirror surfaces not included in the same plane for acting as a two-surface corner reflector on its inner wall, and the light reflected by the mirror surface can pass through the cylindrical body. As long as it can take any shape, it may be a cylindrical body, but it may be a complicated shape in which each cylindrical body is connected or partially missing.

Alternatively, as disclosed in PCT / WO2009-131128 and PCT / WO2009-136578, the dihedral corner reflector is a mirror array (slit mirror array) in which a number of elongated mirror bodies having light reflecting surfaces in the vertical direction are arranged. You may utilize what was piled up so that it might mutually orthogonally cross.

Here, as the optical hole, a shape in which all adjacent inner wall surfaces are orthogonal, such as a cube or a rectangular parallelepiped, can be considered. In this case, the distance between the two-surface corner reflectors can be minimized, and a high-density arrangement is possible. However, it is desirable to suppress reflection on surfaces other than the two-surface corner reflector that faces the object to be observed.

When there are a plurality of mirror surfaces in the two-sided corner reflector, there is a possibility that there are multiple reflected transmitted lights that cause reflection more than the expected number of times. As a countermeasure against this multiple reflection, when two mirror surfaces orthogonal to each other are formed on the inner wall of the optical hole, the surfaces other than these two mirror surfaces are made non-mirror surfaces so that light is not reflected, By providing an angle or providing a curved surface so as not to be vertical, it is possible to reduce or eliminate multiple reflected light that causes three or more reflections. In order to obtain a non-mirror surface, it is possible to employ a configuration in which the surface is covered with an antireflection coating or a thin film, or a configuration in which the surface roughness is roughened to cause irregular reflection. It should be noted that even a transparent and flat substrate does not hinder the function of the optical element, so that the substrate can be arbitrarily used as a support member / protective member.

Furthermore, in order to increase the brightness of the actual mirror image, it is desirable to arrange a plurality of two-sided corner reflectors on the element surface with as little space as possible. For example, it is effective to arrange them in a grid pattern. is there. Further, in this case, there is an advantage that manufacture is also facilitated. As a mirror surface in a two-sided corner reflector, a mirror that reflects a flat surface formed of a glossy substance such as a metal or a resin regardless of whether it is solid or liquid, or between transparent media having different refractive indexes. A material that reflects or totally reflects on a flat boundary surface can be used. Further, when the mirror surface is configured by total reflection, undesired multiple reflection by a plurality of mirror surfaces is likely to exceed the critical angle of total reflection, so that it can be expected to be naturally suppressed. Further, the mirror surface may be formed on a very small part of the inner wall of the optical hole as long as there is no functional problem, and may be constituted by a plurality of unit mirror surfaces arranged in parallel. In other words, the latter aspect means that one mirror surface may be divided into a plurality of unit mirror surfaces. In this case, the unit mirror surfaces do not necessarily have to be on the same plane as long as they are parallel to each other. Further, each unit mirror surface is allowed to be either in contact with or apart from each other.

Furthermore, as another specific example applicable as a real mirror image forming optical system in the present invention, there is provided a retroreflector array that retroreflects light rays and a half mirror having a half mirror surface that reflects and transmits light rays. This is a mirror image forming optical system. In this real mirror image forming optical system, the retroreflector array is arranged at a position where the half mirror surface is a symmetric surface and the light beam reflected or transmitted by the half mirror among the light rays emitted from the observed object can be retroreflected. Yes. The retro-reflector array is disposed only in the space on the same side as the object to be observed (observed object-side space) with respect to the half mirror, and is provided at a position where the light reflected by the half mirror is retroreflected. Here, “retroreflection”, which is the action of the retroreflector, refers to a phenomenon in which the reflected light is reflected (reversely reflected) in the direction in which the incident light is incident. The incident light and the reflected light are parallel and opposite to each other. Become. A plurality of such retroreflectors arranged in an array is a retroreflector array. If the individual retroreflectors are sufficiently small, the paths of incident light and reflected light can be regarded as overlapping. In this retroreflector array, the retroreflectors do not have to be on a plane, may be on a curved surface, and do not have to be on the same plane, and each retroreflector is scattered three-dimensionally. It does not matter. The half mirror refers to a mirror having both a function of transmitting light and a function of reflecting light, and preferably has a transmittance and a reflectance of approximately 1: 1.

The retro-reflector can be composed of three adjacent mirror surfaces (which can be called “corner reflector” in a broad sense) or a cat's eye retro-reflector. The corner reflector includes a corner reflector composed of three mirror surfaces orthogonal to each other, two of the angles formed by the three adjacent mirror surfaces are 90 degrees, and the other angle is 90 / N degrees (N May be an acute angle retroreflector or the like in which the angles formed by the three mirror surfaces are 90 degrees, 60 degrees, and 45 degrees.

In the case of a real mirror imaging optical system that uses such a retroreflector array and a half mirror, the light emitted from the object to be observed is reflected by the half mirror surface, and then retroreflected by the retroreflector array to ensure the original direction. Returning to FIG. 2, the image is transmitted through the half mirror surface, so that the shape and position of the retroreflector array are not limited as long as the reflected light from the half mirror is received. The observed real image can be observed from the direction opposite to the light beam that passes through the half mirror surface.

Here, in addition to a fixed display such as a neon sign or a display panel (a combination of a light source and a display panel such as an emergency light), the object to be observed is an electronic device such as a liquid crystal display, a CRT display, or an organic EL display. Images displayed on the display surface of the display can be used. It is effective that the size of the image on the image surface changes with time. It is also effective to change the position of the image on the image plane with time. The temporal change of the image may be continuous or discontinuous. A display surface of an electronic display can be used as the image surface.

Furthermore, the image plane is effective with respect to the aspect that the three-dimensional display of the image gives an impact. If the object to be observed is a three-dimensional image displayed on the display surface of an electronic display capable of displaying a three-dimensional image, the real mirror image also becomes a three-dimensional image. The object to be observed may be an image that dynamically changes over time. Use of a moving image or a three-dimensional image is more preferable because an effect such as giving an impact to an observer can be obtained.

According to the present invention, the translucent plate disposed between the real mirror image forming optical system and the real image (real mirror image) makes it difficult to see the boundary between the real mirror image optical element and the frame. It is possible to widen a viewing angle range in which an image can be easily viewed as an aerial image.

It is a schematic perspective view for demonstrating the state which engage | inserted the real mirror image optical element in the flame | frame. It is a schematic perspective view for demonstrating the principal part of the display apparatus of embodiment by this invention. It is a schematic side view which shows typically the state which looked at the principal part of the display apparatus of the embodiment from the side. It is a schematic perspective view which shows typically the image formation style of the 2 surface corner reflector array single-piece | unit applied to the embodiment. It is the schematic plan view (a) and partial notch perspective view (b) which show typically the example of a specific structure of the 2 surface corner reflector layout applied to the display apparatus of the embodiment. It is a schematic plan view which shows typically the imaging style by the 2 surface corner reflector array applied to the display apparatus of the embodiment. It is a schematic side view which shows typically the imaging style by the 2 surface corner reflector array applied to the display apparatus of the embodiment. It is a schematic perspective view for demonstrating the case where it observes so that the aerial image by the 2 surface corner reflector array single-piece | unit applied to the embodiment may exist in the center vicinity of a 2 surface corner reflector array. Schematic for explaining a case where the observation position of the observer is changed and observation is performed so that an aerial image by the single-sided corner reflector array applied to the embodiment exists near the end of the double-sided corner reflector array. It is a schematic perspective view shown. It is a schematic side view which shows typically the state which looked at the principal part of the display apparatus of other embodiment of this invention from the side. It is a schematic side view which shows typically the state which looked at the principal part of the display apparatus of further another embodiment of this invention from the side. It is a schematic perspective view which shows typically the aspect of the retroreflection of the light ray by the retroreflector array applied to the real mirror image formation optical system which shows further another embodiment of this invention, and the other example of a retroreflector. FIG. 4 is a schematic partial plan view (a) of a retroreflector array applied to the real mirror image forming optical system, and a schematic partial plan view (b) schematically showing a mode of retroreflection of light rays by an example of the retroreflector. is there. Schematic partial plan view of another retroreflector array applied to the real mirror image-forming optical system (a) and a schematic partial plan view schematically showing a mode of retroreflection of light rays by another example of the retroreflector (B). It is a schematic side view which shows typically the state which looked at the principal part of the display apparatus at the time of applying to digital signage as other embodiment of this invention from the side.

Hereinafter, a display device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic perspective view schematically showing the main part of the display device of the embodiment, and FIG. 3 is a schematic side view schematically showing the state of the main part of the display device of the embodiment viewed from the side. It is.

As shown in FIGS. 2 and 3, the display device forms a real mirror image that partitions a space (observed object side space) in which the observed object 2 is arranged and a space on the observer V side (display side space). A dihedral corner reflector array 6 which is an optical system is included. The double-sided corner reflector array 6 forms a real image 3 (an aerial image which is a real mirror image) of the observation object floating in the display-side space. The display device further includes a semi-transmissive plate 4 disposed between the two-surface corner reflector array 6 and the aerial image 3 in the viewer-side display-side space. The two-sided corner reflector array 6 is fitted into the frame 8.

A part of the light emitted from the object to be observed 2 is reflected twice by the semi-transmissive two-surface corner reflector array 6 and travels toward the observer V, and a part of the light is semi-transmissive. Although reflected or absorbed by the plate 4, the light transmitted through the semi-transmissive plate 4 forms an aerial image 3 as a real mirror image on the line of sight of the observer V.

In the first place, the boundary between the two-surface corner reflector array 6 and the frame 8 which is a real mirror image optical element is visually recognized because the two-surface corner reflector array 6 and the frame 8 are visually recognized. The light is scattered and reflected at different intensities in the two-surface corner reflector array 6 and the frame 8, and the intensity difference is visually recognized as a boundary. The semi-transmissive plate 4 works to suppress the influence of light from the space on the observer side as much as possible, and the light from the object 2 through the two-surface corner reflector array 6 passes through the semi-transmissive plate 4. The light from the space on the observer side is used to pass through the semi-transmissive plate 4 twice while passing only once.

For example, when the transmissivity of the semi-transparent plate 4 is R (<1), the light from the space on the viewer side is reflected by the two-sided corner reflector array 6 and the frame 8, so that the semi-transparent plate 4 , The light from the object to be observed 2 passing through the two-surface corner reflector array 6 passes through the semi-transmissive plate 4 only once, while being attenuated to R ^2. To attenuate. As a result, the ratio of the reflected light to the imaging light becomes R times smaller, and the reflected light becomes relatively weak. That is, if R is reduced, reflected light (that is, the boundary between the two-surface corner reflector array 6 and the frame 8 is observed) can be reduced accordingly.

However, since the brightness of the image formation is also 1 / R, if R is reduced, it is necessary to brighten the object 2 to be observed. Therefore, the brightness is limited by a request for practical brightness.

In order to explain the above imaging mode in more detail, first, the configuration and operation of the two-sided corner reflector array alone will be described, and then the operation when the semi-transmissive plate 4 is added will be described.

As schematically shown in FIG. 4, the single unit of the two-surface corner reflector array 6 is a set of a large number of two-surface corner reflectors 61 each comprising two

mirror surfaces

61a and 61b orthogonal to each other on the base 60. A plane substantially perpendicular to each of the two

mirror surfaces

61a and 61b constituting the entire two-surface corner reflector 61 is defined as an element surface 6S, and the real image of the object to be observed is in a plane-symmetric position with the element surface 6S as a symmetry plane. 3 can be imaged. As the object to be observed, an image 72 displayed on the display surface 71 of the display 7 can be used. If the display 7 is operated and the image 72 displayed on the display surface 71 is moved, the real mirror image 3 also becomes a moving image, which is effective in giving an impact to the observer. In the present embodiment, the two-surface corner reflector 61 is very small (μm order) compared to the overall size (cm order) of the two-surface corner reflector array 6, and therefore the two-surface corner reflector 61 of FIG. The entire set is represented in gray, the direction of the inner angle at which the mirror surface opens is represented by a V shape, and the two-surface corner reflector 61 is exaggerated.

FIG. 5 shows a schematic plan view of the two-sided corner reflector array 6 in FIG. 5 (a), and FIG. 5 (b) shows a partial perspective view. However, in FIG. 5, the two-surface corner reflector 61 and the mirror surfaces 61 a and 61 b are greatly exaggerated as compared with the entire two-surface corner reflector array 6.

The two-sided corner reflector array 6 has a number of physical and optical holes penetrating the thickness perpendicular to the flat surface of the flat base 60 so that light can be transmitted while being bent, for example. In order to form and use the inner wall surface of each hole as the two-sided corner reflector 61, it is possible to employ one in which mirror surfaces 61a and 61b are respectively formed on two orthogonal inner wall surfaces of the hole. Accordingly, as shown in FIGS. 5A and 5B, light having a substantially rectangular shape (for example, square shape) in plan view is transmitted through the thin flat plate-like substrate 60 so that the substrate 60 is at least semi-transmissive. A large number of physical and optical holes (for example, one side of 50 to 200 μm) are formed, and two inner wall surfaces that are adjacent and orthogonal to each other are subjected to smooth mirror surface processing to form mirror surfaces 61a and 61b. Thereby, the two-surface corner reflector 61 in which these two

mirror surfaces

61a and 61b function as reflecting surfaces can be obtained. It should be noted that it is preferable to suppress the multiple reflected light by making the surface of the inner wall surface of the hole that does not constitute the two-sided corner reflector 61 into a surface that is not mirror-reflected and cannot reflect light, or is angled. . In addition, each of the two-surface corner reflectors 61 is preferably formed on a regular lattice point so that the inner angles formed by the mirror surfaces 61a and 61b are all in the same direction on the base 60. Therefore, in each two-surface corner reflector, it is preferable that the intersection line CL of two orthogonal mirror surfaces is orthogonal to the element surface 6S. Hereinafter, the direction of the inner angle of the mirror surfaces 61a and 61b may be referred to as the direction (direction) of the two-surface corner reflector 61.

In forming the mirror surfaces 61a and 61b, for example, a metal mold is first prepared, and the inner wall surface on which the mirror surfaces 61a and 61b are to be formed is subjected to nano-scale cutting processing or a pressing method using the mold to the nano-scale. It is preferable that the mirror surface is formed by processing by the applied nanoimprint method or electroforming method, and that the surface roughness is 10 nm or less so that the surface is uniformly mirrored in the visible light spectrum region. In addition, when the base 60 is formed of a metal such as aluminum or nickel by an electroforming method, the mirror surfaces 61a and 61b naturally become mirror surfaces if the surface roughness of the mold is sufficiently small. However, the nanoimprint method is used. When the substrate 60 is made of resin or the like, it is necessary to perform mirror coating by sputtering or the like in order to create the mirror surfaces 61a and 61b. Moreover, the transmittance | permeability can be improved by setting the separation | spacing dimension of adjacent 2 surface corner reflectors 6 as small as possible. Moreover, it is preferable to perform a process such as applying a low-reflecting agent on the upper surface (the surface visible to the observer) of the two-sided corner reflector array 6. However, the configuration of the two-surface corner reflector array 6 is not limited to that described above, and a large number of two-surface corner reflectors 61 are formed by two orthogonal mirror surfaces 61a and 61b, and each of the two-surface corner reflectors 61 is an optical hole. As long as it transmits light, an appropriate configuration and manufacturing method can be adopted.

In the double-sided corner reflector array 6, each double-sided corner reflector 61 reflects light entering the hole from the back side by one mirror surface 61a (or 61b), and further reflects the reflected light to the other mirror surface 61b (or 61a) has a function of reflecting the light and passing it to the surface side, and the light entrance path and the light exit path are symmetrical with respect to the element surface 6S. That is, the element surface 6S of the two-surface corner reflector array 6 (assuming a surface passing through the center in the height direction of each mirror surface and orthogonal to each mirror surface) is a real image of the object 2 to be observed and an aerial image at a plane-symmetric position ( This is a plane of symmetry to be imaged as (real mirror image) 3.

Here, the image formation mode by the two-surface corner reflector array 6 will be briefly described along with the path of light emitted from the point light source o as an object to be observed.

FIG. 6 is a schematic plan view and FIG. 7 is a schematic side view. As shown in FIG. 7, light emitted from a point light source o (indicated by a one-dot chain line arrow. When the light passes through the two-surface corner reflector array 6, it is reflected by one of the mirror surfaces 61a (or 61b) constituting the two-surface corner reflector 61 and further the other mirror surface 61b (or 61a). After passing through the element surface 6S (FIGS. 7, 4, and 5B), the point light source o passes through the element surface 6S of the two-surface corner reflector array 6 while spreading in a plane-symmetrical position. In FIG. 6, the incident light and the reflected light are shown to be parallel, but this is because the dihedral corner reflector 61 is greatly exaggerated with respect to the point light source o in FIG. 6. Actually, each of the two-sided corner reflectors 61 is extremely small, and therefore, when the two-sided corner reflector array 6 is viewed from above as shown in FIG. In FIG. 6, the path of light that first strikes each of the two mirror surfaces (61 a and 61 b) of the two-surface corner reflector 61, that is, two paths are illustrated. However, in FIG. Only the first light hitting one of the mirrors is drawn). That is, in the end, transmitted light gathers at a position symmetrical with respect to the element surface 6S of the point light source o, and forms an image as a real mirror image at a position p in FIGS.

In the present invention, a semi-transmissive plate (not shown) is disposed between the two-sided corner reflector array 6 and the aerial image 3, but the semi-transmissive plate 4 simply adjusts the light transmittance. Therefore, an aerial image is formed as a real mirror image by the above basic action.

When a half-mirror type semi-transmissive plate is used, part of the light is reflected to adjust the transmittance, and this reflected light is different from the aerial image of the light transmitted through the semi-transmissive plate. (If it is reflected by another object before being imaged, an image cannot be formed), but this image formation is not observed by the observer.

Therefore, when the observer observes only the aerial image 3, the presence or absence of the translucent plate simply changes the brightness of the aerial image.

Next, the operation when a semi-transparent plate is additionally arranged between the two-surface corner reflector array 6 in the display side space and the aerial image 3 will be described.

First, the state of observation of the aerial image 3 when there is no translucent plate is described. Since there is no translucent plate, the observer observes the aerial image 3 as well as the dihedral corner reflector array 6 behind it and the frame 8 for incorporating it.

As shown in FIG. 8, when observing the aerial image 3 so that it is present near the center of the two-sided corner reflector array 6, the eye can be easily focused on the aerial image 3 so that the aerial image can be visually recognized. Cheap.

However, by changing the observation position of the observer, as shown in FIG. 9, the aerial image 3 is in the vicinity of the end portion of the two-surface corner reflector array 6, that is, the portion near the boundary BL between the two-surface corner reflector array 6 and the frame 8. In addition to the aerial image 3, in addition to the aerial image 3, a target for focusing the eye on the boundary BL is created. Therefore, it is difficult to visually recognize the aerial image 3 as an aerial image when focusing on the boundary BL. I found out that

Next, how the aerial image 3 is observed when a semi-transparent plate, which is a feature of the present invention, is added will be described. Due to the added translucent plate, it becomes difficult to observe the boundary BL of the two-sided corner reflector array 6 and the frame 8 for incorporating the same, and not only at the observation position shown in FIG. Even at the observation position shown in FIG. 5, the eyes can be easily focused on the aerial image 3, and the number of observation directions that are easily visible as an aerial image can be increased.
In FIG. 3, the semi-transmissive plate 4 is arranged in the space between the two-surface corner reflector array 6 and the aerial image 3, but the present invention is not limited to this. For example, the semi-transmissive plate 4 may be installed in the form of being bonded to the two-sided corner reflector array 6 and the frame 8 into which it is fitted. Further, the arrangement in the space is not limited to the angle shown in FIG. 3, but can be set at a free angle as long as the effect of the present invention can be exhibited by the semi-transmissive plate.

Furthermore, other embodiments relating to the semi-permeable plate which is a feature of the present invention will be described.

If all the light from the space on the viewer side can be absorbed by the translucent plate, the reflected light from the two-surface corner reflector array and the frame of the real mirror image optical element can be eliminated. It is possible to prevent the boundary from being visually recognized. However, in this case, light from the object to be observed through the two-surface corner reflector array is also absorbed, which makes it impossible to observe an aerial image, which is inconvenient.

Therefore, the inventor considered using an anisotropic translucent plate that passes light from the object to be observed through the two-sided corner reflector array and does not pass other light.

FIG. 10 is an overview diagram showing another embodiment of a display device to which the present invention is applied. Such a display device has the same configuration as the display device of the above-described embodiment except that the anisotropic translucent plate 4a is used instead of the translucent plate 4 (FIG. 3). If the anisotropic semi-transmissive plate 4a is used, the light from the viewer's direction out of the light from the viewer-side space passes through the anisotropic semi-transmissive plate 4a and is a two-sided corner reflector array 6. However, since the light from outside the viewer direction cannot pass through the anisotropic semi-transmissive plate 4a, the two surfaces of the light are not visible. The phenomenon in which the boundary between the corner reflector array 6 and the frame 8 is visually recognized can be prevented, and the effect of making the boundary difficult to see than when an isotropic semi-transmissive plate is used as a whole can be brought out more remarkably. it can. As the anisotropic semi-transmissive plate 4a, for example, a semi-transmissive plate having a fine slit shape can be considered. The slit 4s is a parallel slit or a mesh, and is inclined toward the viewer with respect to the element surface. Moreover, it is preferable that the wall itself which forms a slit is a thing which fully absorbs a light ray. Since the slit is inclined, the transmitted light has directionality, that is, is anisotropic. Specifically, for example, a viewing angle limiting film manufactured by Shin-Etsu Polymer Co., Ltd., trade name VC-FILM has such a function and can be used.

The direction in which light from the space on the viewer side enters the dihedral corner reflector array 6 and the frame 8 by the inclined slit is limited to the viewer's line-of-sight direction V. The observation of the two-surface corner reflector array 6 and the frame 8 and the boundary between them by this light is the light attributed to the viewer due to the scattered reflection from them. Here, if the surfaces of the two-sided corner reflector array 6 and the frame 8 are in a mirror-like state, no scattering reflection occurs, and the light reflected by the surface goes to the opposite side of the observer, It is absorbed by the slit. In other words, the border is not visible, which is more convenient.

As an example of the display device shown in FIG. 10, an example was prepared in which VC-FILM (product number VC-908518) manufactured by Shin-Etsu Polymer Co., Ltd. was used for the anisotropic translucent plate 4a. The anisotropic semi-transmissive plate 4a used in this example has an inclined parallel slit structure, and light from the viewer direction can pass through the anisotropic semi-transmissive plate 4a. Light from other than the observer direction cannot pass through the anisotropic semi-transmissive plate 4a.

Since the anisotropic semi-transmissive plate 4a added also in the present embodiment, the boundary between the two-sided corner reflector array 6 and the frame 8 for incorporating the two-face corner reflector array is difficult to be observed, and at the observation position shown in FIG. Needless to say, the eyes can be easily focused on the aerial image 3 even at the observation position shown in FIG. 9, and the number of observation directions that can be easily viewed as an aerial image can be increased. Furthermore, it was found that the aerial image can be brightened by using the anisotropic semi-transmissive plate 4a.

FIG. 11 is a schematic view showing still another embodiment of a display device to which the present invention is applied. This display device is different from the display device of the above-described embodiment only in the real mirror image forming optical system, and a semi-transparent plate 4 which is a feature of the present invention is combined with a half mirror 91 described later and a real image (real mirror image). ) Between 3). Since the half mirror 91 is fitted into the frame 8 and used, the problem of the boundary is also present in the present display device. Therefore, the problem is solved by adding the semi-transmissive plate 4. The display device includes a real mirror image forming optical system that is a semi-transparent base that partitions a space (observed object side space) in which the observed object 2 is arranged and a space on the viewer V side (display side space). A half mirror 91 is included. The display device of the present embodiment is different from the display device of the above-described embodiment only in the real mirror image forming optical system, and the other configuration is the same, so the same reference numerals using the same reference numerals are used. A description of the configuration is omitted.

The real mirror image forming optical system 9 applied in this embodiment is a combination of a half mirror 91 and a retro reflector array 92 as shown in FIG. And the element surface used as a symmetrical surface becomes the half mirror surface 91S. A display 7 (image 72 displayed on the display surface 71) is arranged as an object to be observed in a space (observed object side space) opposite to the observer V across the half mirror 91, and a retro reflector array 92 is further arranged. The translucent plate 4 is arranged in the observer side space (display side space). The semi-transmissive plate 4 is disposed between the half mirror 91 and the real image (real mirror image) 3.

The light emitted from the object to be observed 2 is reflected by the half mirror 91 and then guided to the retroreflector array 92. Since the retroreflector array 92 has a function of retroreflecting the light from the half mirror 91, the reflected light travels toward the half mirror 91 again. Then, the reflected light passes through the half mirror 91 and then passes through the semi-transmissive plate 4 disposed in the space on the viewer V side, and forms the real mirror image 3 in the space on the line of sight of the viewer V. To do.

As the half mirror 91, for example, a thin reflective film coated on one surface of a transparent thin plate such as transparent resin or glass can be used. By applying anti-reflection treatment (AR coating) to the opposite surface of the transparent thin plate, it is possible to prevent the observed real mirror image 3 from being doubled. As a line-of-sight control means that transmits a light beam in a specific direction and blocks another light beam in a specific direction, or diffuses only a light beam in a specific direction, an optical film (such as a visual field control film or a viewing angle adjustment film) (This is not shown in the figure.) Specifically, this optical film prevents light directly transmitted through the half mirror 91 from reaching any position other than the viewpoint V, thereby allowing the half mirror 91 to pass through. While preventing the observed image on the translucent plate 4 from being directly observable from other than the viewpoint V, it is reflected once by a half mirror 91 (to be described later) and retroreflected. By that transmits only light in a direction through the half mirror 91 after retroreflection by Taarei 92, and can be observed only real mirror image 3 from a particular view point V.

On the other hand, any type of retroreflector array 92 can be applied as long as it reflects incident light strictly, and a retroreflective film or a retroreflective coating may be applied to the surface of the material. Moreover, the shape may be a curved surface or a flat surface. For example, a retroreflector array 92 shown in FIG. 13A with a part of the front view enlarged is a corner cube array that is a set of corner cubes that use one corner of a cubic body corner. Each retroreflector 92A forms a regular triangle when the mirror surfaces 92Aa, 92Ab, and 92Ac that form three isosceles right-angled isosceles triangles are gathered at one point and viewed from the front. The mirror surfaces 92Aa, 92Ab, and 92Ac are orthogonal to each other to form a corner cube (FIG. 13B).

Further, the retroreflector array 92 shown in FIG. 14 (a) by enlarging a part of the front view is also a corner cube array that is a set of corner cubes using one corner of the cubic body. The individual retro reflectors 92B form three regular mirror surfaces 92Ba, 92Bb, 92Bc, which are formed into a single hexagonal shape when the mirror surfaces 92Ba, 92Bb, 92Bc, which form three squares of the same shape and the same size, are viewed from the front. 92Bb and 92Bc are orthogonal to each other (FIG. 14B).

The retroreflector array 92 in FIG. 14 differs from the retroreflector array 92 in FIG. 13A only in shape, and the principle of retroreflection is the same. 13B and 14B, the retroreflector array 92 shown in FIGS. 13A and 14A will be described as an example. Of the mirror surfaces of the

retroreflectors

92A and 92B, FIG. The light incident on one (for example, 92Aa, 92Ba) is sequentially reflected on the other mirror surfaces (92Ab, 92Bb) and further on the other mirror surfaces (92Ac, 92Bc), so that the light has entered the

retroreflectors

92A, 92B. Reflects in the original direction. The paths of the incident light and the outgoing light with respect to the retroreflector array 92 are not strictly overlapping but are parallel to each other. However, when the

retroreflectors

92A and 92B are sufficiently smaller than the retroreflector array 92, the incident light and the outgoing light. May be considered as overlapping. The difference between these two types of corner cube arrays is that the mirror surface is isosceles triangle is relatively easy to create, but the reflectivity is slightly lower, and the mirror surface is square is slightly easier to create than the isosceles triangle. While difficult, it has a high reflectivity.

In addition to the above-described corner cube array, a retroreflector array 92 that can retroreflect light rays by three mirror surfaces (“corner reflector” in a broad sense) can be adopted as the retroreflector array 92. Although not shown, for example, as a unit retroreflective element, two mirror surfaces of three mirror surfaces are orthogonal to each other, and another mirror surface is 90 / N degrees with respect to the other two mirror surfaces (where N is an integer) Or an acute-angle retroreflector having angles of 90 degrees, 60 degrees, and 45 degrees formed by three mirror surfaces that are adjacent to each other are suitable as the retroreflective element 3 applied to the present embodiment. In addition, a cat's eye retro reflector or the like can also be used as a unit retroreflective element. These retro-reflector arrays may be planar or bent or curved. Also, the arrangement position of the retroreflector array can be set appropriately as long as the light emitted from the image 72 and reflected by the half mirror 91 can be retroreflected.

In the display device of this embodiment to which the real mirror image forming optical system 9 including the half mirror 91 and the retroreflector array 92 is applied, the half mirror 91 is similar to the display device to which the two-surface corner reflector array is applied. On the other hand, the real mirror image 3 appears to float in the space on the line of sight of the observer viewing from an oblique direction. Also in this display device, the actual mirror image 3 can be changed by changing the display position and size of the observation image.

Also in the display device of the present embodiment, since the semi-transmissive plate 4 merely adjusts the light transmittance, an aerial image is formed as a real mirror image by the above basic action. The case where a half mirror type semi-transmissive plate is used is the same as in the case of the display device. Therefore, also in the case of this display device, when the observer observes only the aerial image 3, the presence or absence of the semi-transmissive plate merely changes the brightness of the aerial image.

Even in this embodiment, the boundary between the half mirror 91 and the frame 7 for incorporating the half mirror 91 is less likely to be observed when the semi-transparent plate is added than when the semi-transparent plate is not added. It was possible to easily focus the eyes on the aerial image 3 and to increase the number of observation directions that are easily visible as an aerial image.

Although the present invention has been described above by the embodiments, the specific configuration of each part of the display device can be changed as appropriate without departing from the spirit of the present invention.
In addition, as an application example of the present display device, not only a simple display device that raises an aerial image but also various devices such as an automobile instrument panel in which a display unit is provided in a deep part. The present invention can be appropriately configured as a display device that causes an aerial image to appear in front of the display unit.

Furthermore, if the translucent plate 4 shown in the present invention is arranged on the wall surface or the surface of the column surface, the aerial image jumps out from the wall surface or the column surface perpendicular to the floor surface to the front space. Therefore, the present invention can be effectively applied to digital signage or the like (see FIG. 15).
FIG. 15 is a schematic view showing still another embodiment of a display device to which the present invention is applied. The display device is different from the display device of the above-described embodiment only in the arrangement of the components, and the semi-transparent plate 4 is set up vertically between the two-surface corner reflector array 6 and the real image (real mirror image) 3. Are arranged. Since the double-sided corner reflector array 6 is used by being fitted into the frame 8, the boundary problem still exists in the present display device, but the problem is solved by the addition of the translucent plate 4. The display device of this embodiment is different from the display device of the above-described embodiment only in the real mirror image forming optical system, and the other configuration is the same. A description of the configuration is omitted.

2 ... Object 3 ... Aerial image (real mirror image)
4 ... Semi-transmissive plate 5 ... Real mirror image optical element 6 ... Two-sided corner reflector array (real mirror image imaging optical system)
6S: Element plane (symmetric plane)
61 ... Two-

surface corner reflectors

61a, 61b ... Mirror surface 7 ... Display 71 ... Display surface 72 ... Object to be observed (image)
8 ... Frame 91 ... Half mirror 91S ... Half mirror surface (symmetrical surface)
92 ...

Retro reflector arrays

92A, 92B ... Retro reflectors 92Aa, 92Ab, 92Ac, 92Ba, 92Bb, 92bc ... Mirror plane CL ... Intersection line of mirror planes

Claims

A real image of the object to be observed is provided in the display side space through the base having a translucent base that partitions the display side space that can be visually recognized by the observer and the object side space on which the object is placed. A real mirror image forming optical system to form an image;
A display device comprising: the base and a translucent plate disposed between the real image of the object to be observed.
The display device according to claim 1, wherein the translucent plate is an anisotropic translucent plate.
3. The display device according to claim 1, wherein the translucent plate has a larger area than the base.
4. The display device according to claim 1, wherein the object to be observed is an image displayed on an image surface having a predetermined shape.
The display device according to claim 4, wherein the image surface is a display surface of an electronic display.
The display device according to claim 4 or 5, wherein the image plane displays the image three-dimensionally.
The display device according to any one of claims 1 to 6, wherein the base of the real mirror image forming optical system is an optical element that functions as a two-surface corner reflector.
The display device according to any one of claims 1 to 6, wherein the real mirror image forming optical system is formed by a combination of a half mirror and a retroreflector array, and the base is the half mirror.