JP5565845B2 - Volume scanning type 3D aerial image display - Google Patents

Description

  The present invention relates to a display capable of displaying a stereoscopic aerial image by a volume scanning method.

  In recent years, techniques for enabling viewing of stereoscopic images have been developed. Many of the stereoscopic display devices in practical use currently use only binocular parallax among the stereoscopic factors, but there are technical problems such as focus adjustment and convergence, and eyes can be seen by watching for a long time. There are also problems such as fatigue, and there is a demand for technologies that are easier to use. For example, assuming that a convex lens or a concave mirror is used as the imaging optical system, a two-dimensional display capable of high-speed display is arranged inclined with respect to the optical axis of the optical system, and two-dimensional inclined with respect to the optical axis by a mirror scanner There has been proposed a stereoscopic display method of a three-dimensional image by a volume scanning method in which a three-dimensional image is formed by moving an image and displaying a cross-sectional image of a display object on a two-dimensional display accordingly (non-patent document). Reference 1). According to this method, since a three-dimensional real image is formed, a wearing object such as eyeglasses is unnecessary, and it can be said that it can satisfy all human stereoscopic perception factors.

“Volumetric display system based on three-dimensional scanning of inclined optical image”, Daisuke Miyazaki et al, Optic Express, Vol. 14 Issue 26, pp12760-12769

  In the stereoscopic display method as disclosed in Non-Patent Document 1, since a convex lens or a concave mirror is used as an optical system, distortion occurs in the shape due to the aberration, and it is difficult to completely stabilize the localization. is there.

  On the other hand, the present inventor, as an equal-magnification imaging optical system, uses a real mirror image forming element (hereinafter referred to as “two surfaces” as necessary) which is an optical element provided with a number of two-surface corner reflectors composed of two mirror surfaces. (Referred to as “Corner Reflector Array”) (see Japanese Patent Application No. 2006-080009) and a real mirror image forming optical system using a retro-reflector array having a retroreflective function and a half mirror (Japanese Patent Application No. 2007-163323) Has been proposed). In addition, using an afocal lens array equipped with an afocal optical system with an infinite focal length, the element surface of the afocal lens element is used as a symmetry plane, and the image of the projection object is formed in the opposite space. A real mirror image forming optical system that has been realized has also been proposed (see Japanese Patent Application No. 2005-10755). In addition, the above-described two-surface corner reflector array is configured so that the two-surface corner reflector is directed in a plurality of directions, or in a real mirror image forming optical system using retroreflection, the retroreflector array and the half mirror surround the projection object. In some cases, it has been proposed to make it possible to observe a real mirror image from a plurality of directions by devising a structure such as (see Japanese Patent Application Nos. 2007-054871 and 2007-211992). These real mirror image forming optical systems have a plane-symmetrical position with respect to a symmetry plane (element surface of a two-surface corner reflector array, half mirror surface, element surface of an afocal lens array) in which the projection object is set in the optical system. The image is formed as a real image with the same magnification without distortion, and a two-dimensional real image can be observed if the projection object is two-dimensional, and a three-dimensional real image can be observed if the projection object is three-dimensional. It is.

  Accordingly, the main object of the present invention is to provide a three-dimensional aerial image display based on a volume scanning method using the above-described real mirror image forming optical systems, particularly a distortion-free three-dimensional aerial image display.

That is, the present invention provides a real mirror image forming optical system capable of forming a real image of a projection object as a mirror image at a plane symmetrical position with respect to a certain geometric plane as a symmetry plane, and a lower surface side of the symmetry plane. And a display having a display surface for displaying an image as the projection object on both the front surface and the back surface, and driving means for operating the display so as to perform a motion including a component in a direction perpendicular to the display surface And changing the image displayed on the display surface in synchronization with the operation of the display by the driving means, thereby converting the image into a space on the upper side of the symmetry plane (hereinafter referred to as “stereoscopic aerial image”). A volume-scanning three-dimensional aerial image display device (hereinafter referred to as a “three-dimensional aerial image display device” for the sake of simplicity). Is that).

  In such a three-dimensional aerial image display device, the real mirror image forming optical system forms a real image having no distortion at a plane symmetrical position with respect to the projection object as a mirror image with respect to the symmetry plane. However, the depth of the observed real image is reversed from the depth of the projection object. In addition, the display applied to the present invention includes not only a display device in a general sense of displaying an image on a screen but also an entire display capable of displaying an image such as a screen that projects an image projected by a projector or the like. In other words, the display surface may be a curved surface as well as a flat surface. The drive means and the display make a movement including a component in a direction perpendicular to the display surface, that is, a three-dimensional movement filling the three-dimensional space, so that the drive means and the display are substantially volume scanning type three-dimensional display. Function as. As the driving means, an appropriate mode may be adopted in which the display is operated according to a motion that fills a desired three-dimensional space. Here, it is only necessary for the movement of the display to move so that the display surface fills some three-dimensional space, including vibration in a certain direction, and what kind of component is included as long as it includes a component in a direction perpendicular to the display surface? It may be exercise. However, the expression “three-dimensional movement to fill the three-dimensional space” or “three-dimensional movement” or “three-dimensional movement” does not necessarily mean that the display operates with three degrees of freedom, but one degree of freedom. Even a motion of a degree includes a motion to fill a predetermined three-dimensional space. Note that the display is preferably arranged in a range where the real image of the video displayed on the display surface can be observed from a certain viewpoint on the upper surface side of the symmetry plane, but the image is temporarily invisible during the stereoscopic operation. It is permissible for the display to come in position. According to the three-dimensional aerial image display device of the present invention as described above, a display that makes a three-dimensional motion to fill the three-dimensional space in the space on one side of the symmetry plane using the real mirror image forming optical system, in other words, Then, the real image of the image displayed on the volume scanning type stereoscopic display can be displayed and observed as an aerial stereoscopic image without distortion in the space on the other side.

  As a kind of real mirror image forming optical system suitable for use in the present invention, a plurality of two-surface corner reflectors composed of two mirror surfaces perpendicular to each other perpendicular to a predetermined element plane are arranged on the element plane. In addition, a two-sided corner reflector array whose element plane is the plane of symmetry can be mentioned. If it is such, when the light from the image which is a projection object permeate | transmits an element plane, it reflects once by the two mirror surfaces of each two-surface corner reflector, and the component of the light parallel to an element plane Is retro-reflected to form an image as a real image in the air at a symmetrical position on the upper surface of the element plane. That is, the observer can observe a real image of the image formed by reflection by the two-surface corner reflector in which the inner angles of the two mirror surfaces face the line-of-sight direction, that is, a stereoscopic aerial image.

  Here, in order to allow a stereoscopic aerial image to be observed from a plurality of viewpoints, a plurality of two-surface corner reflectors that are formed in a plurality of directions in a rotation direction having a rotation axis perpendicular to the element plane is adopted. Thus, it is possible to configure a three-dimensional aerial image display device that can form a stereoscopic image in a space on the same side as the stereoscopic image with respect to the element plane and observe it from a plurality of directions. More specifically, it is only necessary that each of the two-surface corner reflectors has an opening in the direction of the stereoscopic scanning type stereoscopic display arranged on the lower surface side of the element plane that is a symmetrical plane. Specifically, as a real mirror image forming optical system using a two-surface corner reflector, a two-surface corner reflector array is configured by a set of a plurality of two-surface corner reflector arrays sharing an element plane. In such a case, for example, a two-sided corner having a two-sided corner reflector facing in the same direction as compared with a mode in which a two-sided corner reflector is formed simultaneously in a plurality of directions on a single element plane. A plurality of reflector arrays can be combined in a planar manner so as to function as a single two-sided corner reflector array, thereby making it possible to reduce manufacturing ease and cost. In addition, a plurality of two-surface corner reflector arrays each having a two-surface corner reflector facing a predetermined point may be combined in a plane so as to face different directions so as to function as a single two-surface corner reflector array. it can.

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

  To simply describe the structure of the dihedral corner reflector array, a large number of mirror surfaces substantially perpendicular to the element plane are arranged on the element plane. The problem as a structure is how to support and fix the mirror surface on the element plane. As a more specific method of forming a mirror surface, for example, a two-sided corner reflector array is provided with a base that divides a predetermined space, and one plane passing through the base is defined as an element plane. The reflector can be used as an optical hole assumed in a direction penetrating the element plane, and the inner wall of the hole formed in the substrate can be used as a mirror surface. The hole formed in the substrate only needs to be transparent so that light can pass through, 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 one or more mirror surfaces not acting on the same plane for acting as a unit optical element, and the light reflected by the mirror surface can pass through the holes. It is possible to take a complicated shape in which each hole is connected or a part of the hole 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 two-surface 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. As for the shape of the cylindrical body, as long as the inner wall has one or more mirror surfaces not included in the same plane for acting as a two-surface corner reflector, and the light reflected by the mirror surface can pass through the cylindrical body It is possible to take any shape, and although it is referred to as a cylindrical body, it may be a complicated shape in which each cylindrical body is connected or partly missing.

  Here, as the optical hole, a shape in which the adjacent inner wall surfaces are all 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 direction of the projection object.

  When there are a plurality of mirror surfaces in the two-sided corner reflector, there is a possibility that there is multiple reflected transmitted light that causes 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. In addition, since the presence of a transparent and flat substrate does not hinder the function of the optical element, the substrate can be arbitrarily used as a support member / protective member.

  Furthermore, in order to increase the brightness of a real mirror image, that is, a stereoscopic aerial image, it is desirable to arrange a plurality of two-sided corner reflectors on the element plane as far as possible from each other, for example, in a grid pattern. It is effective to do. Further, in this case, there is an advantage that manufacture is also facilitated. As a mirror surface in a two-sided corner reflector, regardless of whether it is solid or liquid, it reflects on a flat surface formed of a glossy substance such as metal or resin, 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.

  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, or 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. In the case where the two-surface corner reflector array is configured as a real mirror image forming element, a two-surface corner reflector with two orthogonal mirror surfaces is required. Therefore, one unit optical element has two orthogonal mirror surfaces. Must be formed. The two mirror surfaces that are orthogonal to each other are not necessarily in contact with each other. When light is transmitted from one side of the element plane to the other side, it is only necessary to reflect the two mirror surfaces once. Either a mode in which the mirror surfaces are in contact with each other or a mode in which they are separated is allowed.

  Further, as another real mirror image forming optical system applied to the present invention, it comprises a retroreflector array that retroreflects light rays and a half mirror having a half mirror surface that reflects and transmits light rays, The half mirror surface may be a symmetrical surface in the real mirror image forming optical system, and the retroreflector array may be arranged in the same space as the projection object with respect to the half mirror. 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. Such a retroreflector arranged in an array is a retroreflector array, and when 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 need to be on the same plane, and the retroreflectors may be three-dimensionally scattered. 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.

  As the retro reflector, one composed of three adjacent mirror surfaces (which can be called a “corner reflector” in a broad sense) or a cat's eye retro reflector can be used. 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 such a multi-viewpoint aerial image display optical system using a retroreflector array and a half mirror, the light emitted from the projection object 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. And the observation of the formed real image can be observed from the direction opposite to the light beam transmitted through the half mirror surface, and since the half mirrors are set at an angle of less than 180 degrees on the real image side, The real image of the projection object can be observed from a plurality of viewpoints corresponding to the number of half mirrors.

  As described above, in the three-dimensional aerial image display apparatus to which the real mirror image forming optical system using the retro reflector array and the half mirror is applied, the retro reflector is displayed on the display together with the half mirror at least on the back surface side of the half mirror. If the plane is arranged so as to surround it three-dimensionally, a stereoscopic aerial image can be observed from a plurality of viewpoints.

  In addition to the above, as another real mirror image forming optical system applied to the present invention, an afocal lens in which a plurality of afocal lenses having an optical axis perpendicular to a predetermined element plane are arranged on the element plane. An array having an element plane as a plane of symmetry can be mentioned. An afocal lens has an infinite focal length, and can be composed of, for example, two lenses having an optical axis perpendicular to the element plane and spaced apart from each other. An afocal lens array can be configured by arranging a number of afocal lenses arranged side by side on the element plane. As a configuration of the afocal lens, a convex lens, an optical fiber lens, or the like can be employed.

In 3D floating image display device of the present invention as mentioned above, the display, it is intended to comprise a display surface on both sides of the front and back. If configured in this way, especially when the display is arranged with both display surfaces upright with respect to the symmetry plane within a range where the stereoscopic aerial image of the images on both display surfaces can be confirmed when viewed from the viewpoint on the upper surface side of the symmetry plane Since the images displayed on both display surfaces can be viewed from the facing direction, a stereoscopic aerial image can be multi-viewpointed. When the same image is displayed on both display surfaces, it is possible to observe the same stereoscopic image from multiple viewpoints and to actively use the fact that different images can be displayed on both display surfaces. For example, it is possible to display and observe a three-dimensional aerial image viewed from the same direction or a completely different three-dimensional aerial image even when viewed from the opposite side. Further, when different images are displayed on both display surfaces, the front and back surfaces of the stereoscopic aerial image can be individually displayed, and the stereoscopic aerial image that does not become a perspective image can be displayed. Furthermore, since the depth of the image by the real mirror image forming optical system used in the present invention is reversed, in order to display a normal three-dimensional aerial image, it is necessary to reverse the depth of the projection object in advance. By using a double-sided display, the depths of the front and back surfaces can be displayed separately. However, when an afocal lens array is applied as a real mirror image forming optical system, a stereoscopic aerial image can hardly be seen if the display surface is perpendicular to the element surface which is a symmetrical surface.

  In addition, in the three-dimensional aerial image display device of the present invention, the display is arranged with its display surface facing the symmetry plane of the real mirror image forming optical system (when the display surface is perpendicular to the symmetry plane). Except), the driving means may be configured to operate the display so as to make a motion including a component perpendicular to the plane of symmetry. In this way, since video for each viewpoint cannot be displayed, only a perspective video can be displayed. However, even if the display has only one display surface, a stereoscopic aerial video can be multi-viewed.

According to the present invention, a real mirror image forming optical system that forms a real image of a projection object at a plane-symmetrical position with respect to a certain geometric plane (symmetric plane), a double-sided display that functions as a volume scanning stereoscopic display, and a drive New 3D aerial image display that allows the image displayed on the volume scanning display to be imaged as a 3D aerial image without distortion in the space opposite to the symmetry plane. It is possible to provide a method and an observation method.

1 is a perspective view schematically showing a basic configuration of a three-dimensional aerial image display device according to a first embodiment of the present invention. The top view which shows typically the 2 surface corner reflector array which is a real mirror image formation optical system applied to the embodiment. The perspective view which expands and schematically shows a part of the same 2 side corner reflector array. The figure which shows typically the image formation mode by the same 2 surface corner reflector array. The figure which shows typically the relationship between the image | video of the display in the same three-dimensional aerial image display apparatus, and its three-dimensional aerial image | video. The perspective view which shows roughly the three-dimensional aerial image display apparatus which applied the double-sided display as the same embodiment, and performed multi-viewpoint. The perspective view which shows roughly the three-dimensional aerial image display apparatus which performed multi-viewpoint as a modification of the embodiment. The schematic perspective view which shows the other example of the 2 surface corner reflector array applied to the embodiment. The side view which shows schematically the basic composition of the three-dimensional aerial image display apparatus of 2nd Embodiment of this invention. The schematic front view which expands and shows a part of retro reflector array which is a real mirror image formation optical system applied to the embodiment. The figure which shows typically the mode of the reflection of the light ray by the retro-reflector array. The side view which shows roughly the three-dimensional aerial image display apparatus which applied the double-sided display as the same embodiment, and performed multi-viewpoint. The side view which shows roughly the three-dimensional aerial image display apparatus of 3rd Embodiment of this invention. The figure which shows typically the structure of the afocal lens array which is a real mirror image formation optical system applied to the embodiment, and an image formation style.

  Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment First, a first embodiment of the present invention will be described with reference to FIGS. A basic configuration of a volume scanning type 3D aerial image display device (hereinafter abbreviated as “3D aerial image display device”) X1 according to the present embodiment is as shown in FIG. As one type, a real mirror image forming element (hereinafter referred to as a “two-sided corner reflector array”) 2 in which a large number of two-sided corner reflectors 1 are formed, and a display 3 having a display surface 31 for displaying an image, The display 3 is provided with driving means 4 for causing a three-dimensional movement. In other words, the image O sequentially displayed on the display surface 31 of the moving display 3 forms the stereoscopic aerial image P as a real image (real mirror image) of the mirror image by the two-surface corner reflector array 2A in this embodiment. Is the projection object. Hereinafter, each part will be described.

  In the two-surface corner reflector array 2A, an element plane S1 is a plane substantially perpendicular to each of the two mirror surfaces 11 and 12 constituting the entire two-surface corner reflector 1, and the element plane S1 is a symmetry plane. A real mirror image of the image O, which is the projection object, is formed at the plane-symmetric position, and the stereoscopic aerial image P is observed. In this embodiment, since the two-surface corner reflector 1 is very small compared to the entire two-surface corner reflector array 2A, the entire set of the two-surface corner reflectors 1 is shown in gray in FIG. The direction is represented by a V-shape. As shown in FIG. 2, the two-sided corner reflector array 2 </ b> A includes a flat plate-like base 21, and a plurality of holes 22 penetrating the wall thickness perpendicular to the flat base surface are formed on the base 21. In order to use the inner wall surface of the hole 22 as the two-surface corner reflector 1, the mirror surfaces 11 and 12 are respectively formed on two orthogonal inner wall surfaces of the hole 22.

  The base 21 is a thin plate having a thickness dimension of, for example, 50 to 200 μm, and in the present embodiment, 100 μm, and a square in plan view having a side of about 5 cm is applied. The dimensions can be appropriately set without being limited to these. As shown in FIG. 3 by enlarging part A of FIG. 2, each two-sided corner reflector 1 is formed using physical and optical holes 22 formed in the base 21 to transmit light. It is. In the present embodiment, first, a large number of holes 22 having a substantially rectangular shape in plan view (specifically, a square shape in the present embodiment) are formed in the base 21, and smooth mirror surfaces are formed on two adjacent inner wall surfaces orthogonal to each other among the holes 22. The mirror surfaces 11 and 12 are processed to form a two-surface corner reflector 1 that functions as a reflecting surface. In addition, it is preferable to suppress a part of the inner wall surface of the hole 22 other than the two-surface corner reflector 1 from being subjected to mirror surface treatment so that light cannot be reflected, or to prevent multiple reflected light by providing an angle. . Each two-surface corner reflector 1 is formed on the base 21 so that the inner angles formed by the mirror surfaces 11 and 12 are all in the same direction. Hereinafter, the direction of the inner angle of the mirror surfaces 11 and 12 may be referred to as the direction (direction) of the dihedral corner reflector 1. In forming the mirror surfaces 11 and 12, in the present embodiment, a metal mold is first created, and the inner wall surface on which the mirror surfaces 11 and 12 are to be formed is subjected to nanoscale cutting processing to form the mirror surfaces. The surface roughness is 10 nm or less, and the surface is uniformly mirrored with respect to the visible light spectrum region.

  Specifically, each of the mirror surfaces 11 and 12 constituting each two-sided corner reflector 1 has a side of, for example, 50 to 200 μm, and in this embodiment, 100 μm corresponding to the thickness of the base 21. A plurality of substrates are formed at a predetermined pitch on a single substrate 21 by a nanoimprint method or an electroforming method in which the conventional press method is applied to the nanoscale. In this embodiment, each side that forms a V shape on the element plane S of each two-sided corner reflector 1 is rotated 45 degrees with respect to the width direction or depth direction of the base 21 and all the two-sided corner reflectors 1 are rotated. Are aligned on regular lattice points assumed on the element plane S1 so as to face the same direction. In addition, the transmittance | permeability can be improved by setting the separation | spacing dimension of adjacent 2 surface corner reflectors 1 as small as possible. In addition, a portion of the base 21 other than the portion where the two-surface corner reflector 1 is formed is subjected to a light shielding process, and a transparent reinforcing material having a thin plate shape (not shown) is provided on the upper and lower surfaces of the base 21. In the present embodiment, a two-surface corner reflector array 2A in which tens of thousands to hundreds of thousands of such two-surface corner reflectors 1 are provided on the base 21 is employed.

  In addition, when the base | substrate 21 is formed with metals, such as aluminum and nickel, by the electroforming method, if the surface roughness of a metal mold | die is small enough, it will become a mirror surface naturally by it. When the substrate 21 is made of resin or the like using the nanoimprint method, it is necessary to perform mirror coating by sputtering or the like in order to create the mirror surfaces 11 and 12.

  The double-sided corner reflector 1 formed on the base 21 in this way reflects light entering the hole 22 from the front surface side (or back surface side) of the base 21 by one mirror surface (11 or 12) and further reflects the reflected light. Is reflected by the other mirror surface (12 or 11) and passes to the back surface side (or front surface side) of the base plate 21. The light entrance path and the light emission path are symmetrical with respect to the base plate 21. Therefore, by forming a large number of two-sided corner reflectors 1 on the base 21 as described above, the two-sided corner reflector array 2A functions. That is, the element plane S1 of the two-surface corner reflector array 2A (assuming a plane that passes through the central portion of the thickness of the base 21 and is orthogonal to each mirror surface and is indicated by an imaginary line in FIG. It becomes a symmetric plane that forms a real image of the projection object on the side as a mirror image (real mirror image) at a plane symmetric position on the other side.

  Here, an image formation mode by the two-surface corner reflector array 2A will be briefly described along with a path of light emitted from the point light source o as a projection object. 4 (a) is a schematic plan view, and FIG. 4 (b) is a schematic side view. As shown in FIG. 4 (b), light emitted from a point light source o (indicated by an arrow and a solid line). The two-sided corner reflector 1 travels from the back side to the front side of the sheet when passing through a hole 22 (omitted in the figure) formed in the base 21 (omitted in the figure) of the two-sided corner reflector array 2A. Is reflected by one mirror surface 11 (or 12) constituting the light source and further reflected by the other mirror surface 12 (or 11) and then transmitted through the element plane S1 (the light beam of the transmitted light is indicated by a broken line), a two-surface corner reflector array The point light source o passes through the element plane S1 of 2A (omitted in the figure) while spreading in a plane symmetrical position (position o in the figure). That is, in the end, the transmitted light gathers at a plane symmetric position of the point light source o with respect to the element plane S1, and forms an image as a real mirror image p.

  The display 3 may be a curved surface, but an appropriate known display can be used as long as the display surface 31 is substantially flat. In the present embodiment, as shown in FIG. 1, a display 3 having a flat display surface 31 is employed, and the display surface 31 is perpendicular to the element plane S1 in the space on the lower surface side of the two-surface corner reflector array 2A. Placed in. The arrangement orientation of the display 3 is not necessarily limited to this, and a real image of the video O displayed on the display surface 31 can be seen when viewed from a certain viewpoint on the upper surface side of the two-surface corner reflector array 2A. If it is a posture, it can be set appropriately.

  The driving means 4 gives a three-dimensional operation to the display 3 and is an appropriate configuration using a motor, a spring, a gear, a gear, a rail or the like as long as it is a mechanism or device for driving other objects. Things are available. In the present embodiment, as shown in FIG. 1, the driving means 4 is arranged so that the display 3 (and the display surface 31) is parallel to the element plane S1 in the space on the lower surface side of the element plane S1 of the two-sided corner reflector array 2A. A configuration that vibrates (reciprocates) is adopted. As the driving means 4 for causing the display 3 to perform such reciprocating motion, for example, a rail (not shown) parallel to the element plane S1 of the two-sided corner reflector array 2 and a motor (not shown) that reciprocates the display 3 along this rail. A driving device such as can be applied. The video O displayed on the display surface 31 of the display 3 is sequentially changed corresponding to the change in the position of the display 3 by the driving unit 4. As described above, since the display 3 is three-dimensionally moved by the driving unit 4, the display 3 and the driving unit 4 function as a volume scanning type three-dimensional display.

  Here, the movement of the display 3 is a reciprocating movement while keeping the display surface in parallel, but it is not necessarily required to be parallel. Further, it is not always necessary to consider the relationship with the element plane for the direction of motion. Furthermore, although vibration (reciprocating motion) is used as the motion, it is not always necessary to reciprocate, and a circular motion in one direction is also possible.

Next, in the three-dimensional aerial image display device X1 of the present embodiment, the image O sequentially displayed on the display surface 31 of the display 3, and the stereoscopic aerial image P formed by the two-surface corner reflector array 2A of the image O, Will be described with an example. In this example, an image O in which a sphere is drawn by the display 3 being half of the reciprocating movement (outward and backward) is sequentially displayed on the display surface 31, and accompanying this, a three-dimensional aerial image P of a sphere that is a real image (however, Indicates that the depth is inverted). The positional relationship between the dihedral corner reflector array 2A and the display 3 as shown intermittently over time in FIG. 5 (a), the display 3 during one reciprocation, in the drawing at time t ₁ ~t ₉ each position shown, i.e. to start the oscillation at time t _1, reaches the amplitude other end at the position of t _5, it is assumed to return to the same position as t ₁ at the position of t _9. At each time t _{1 to} t ₉ , as shown in FIG. 5B, circle figures having a constant center position and different diameters are sequentially displayed on the display surface 31 of the display 3. Correspondingly, as shown in FIGS. 4A and 4C, the real mirror image P of the image O at each time is located at a plane symmetrical position with respect to the element plane S1 of the two-surface corner reflector array 2A of the display surface 31. As shown in FIG. Since the actual movement of the display 3 is continuous, the stereoscopic aerial image P can be seen as a perspective image of a sphere from the observer's viewpoint V1. Note that this sphere has a stereoscopic image created by the movement of the display 3 and an inverted depth.

  As described above, according to the three-dimensional aerial image display device X1 of the present embodiment, the display 3 and the driving unit 4 function as a substantial three-dimensional display, and images continuously displayed on the display surface 31 of the display 3 are displayed. O can be imaged as a real 3D aerial image P with no distortion at the plane of symmetry with respect to the element plane S1 through the two-surface corner reflector array 2A, so it floats in the air and moves the viewpoint vertically and horizontally In contrast, it is possible to provide a new 3D video presentation style called 3D aerial video that is completely stationary in the air.

In addition, when the two-surface corner reflector array 2A composed of the two-surface corner reflectors 1 facing the same direction is used, the viewpoint is limited to a certain direction, but the orientation of the two-surface corner reflector 1 is set in a plurality of directions. By using the two-surface corner reflector array 2A directed to the three-dimensional aerial image display device X1 ′ capable of observing the stereoscopic aerial image P from a plurality of viewpoints. That is , as shown in FIG. 6, the three-dimensional aerial video display device X1 ′ of the present embodiment has two components having the same configuration as the two-surface corner reflector array 2A used in the basic configuration of the above-described embodiment (see FIG. The two-plane corner reflector arrays 2A and 2B) are arranged so that the respective element planes S1 and S1 ′ are flush with each other and the two-plane corner reflector 1 faces each other, and the display has display surfaces 31 and 31 on both sides. The two-sided display 3 ′ is operated three-dimensionally by the driving means 4, and the images O displayed on both display surfaces 31 and 31 are synchronized with the display position as the same on both sides, so that the two perspectives V1 and V1 ′ have the same shape. The stereoscopic aerial image P can be observed simultaneously. In addition, a two-surface corner reflector array 2A in which the two-surface corner reflector 1 is directed in a plurality of directions in another manner is adopted, and a plurality of displays 3 or display surfaces 31 are arranged in accordance with the direction of the two-surface corner reflector 1. The three-dimensional aerial image P can be made multi-viewpoint by appropriately operating them by the driving means 4. Note that the images O displayed on both display surfaces 31 and 31 can be different. For example, if the front and back surfaces of a stereoscopic aerial image are individually displayed, a stereoscopic aerial image that does not become a perspective image is displayed. Is possible. Furthermore, since the depth of the image by the real mirror image forming optical system used in the present invention is reversed, in order to display a normal three-dimensional aerial image, it is necessary to reverse the depth of the projection object in advance. By using both sides as the display surface, it is possible to display the front and back surfaces separately in depth-reversed display.

  Similarly, assuming that two two-surface corner reflector arrays 2A1 and 2A2 are used, the display surface 31 of the display 3 is an element plane S1 that is a symmetric surface as in the three-dimensional aerial image display device X1 ″ shown in FIG. , S1 ′, the display 3 can be three-dimensionally moved in the direction perpendicular to the element planes S1 and S1 ′ by the driving means 4. In this case, even when the display surface 31 is one, observation from multiple viewpoints (two viewpoints of viewpoints V1 and V1 ″ in the illustrated example) is possible. However, in this case, since the video cannot be changed for each viewpoint, only the perspective stereoscopic image can be displayed.

  Further, the two-surface corner reflector constituting the two-surface corner reflector array only needs to have two orthogonal reflecting surfaces, and this reflecting surface includes a mirror surface accuracy flatness of a material that reflects light such as metal. It is possible to use phenomena such as reflection by an end face or film having a thickness, and total reflection at a boundary having a mirror surface accuracy flatness between transparent media having different refractive indexes. More specifically, for example, in the above-described embodiment, in the two-surface corner reflector array 2A, the square-shaped hole 22 is formed in the thin plate-like base 21, and two adjacent two of the inner peripheral walls of the hole are used as two. Although the surface corner reflector is formed, instead of such a configuration, as shown in an enlarged view in FIG. 8, the two-surface corner reflector 1 ′ is provided on each of the transparent cylindrical bodies 23 protruding in the thickness direction of the base 21. It is good also as 2 side corner reflector array 2A 'which formed and formed many such cylindrical bodies 23 in the grid shape. In this case, the two-surface corner reflector 1 ′ can be formed also by an aspect in which two orthogonal surfaces among the inner wall surfaces of each cylindrical body 23 are mirror surface elements 11 ′ and 12 ′. In this case, similarly to the above-described embodiment, the light reflected twice by the two-surface corner reflector 1 ′ passes through a point that is plane-symmetric with respect to the surface direction of the substrate 21, that is, the element plane S 1 ′. A three-dimensional aerial image can be formed in a space opposite to the object plane S1 ′.

  It should be noted that the inner wall surface other than the mirror surface elements 11 ′ and 12 ′ of the cylindrical body 23 is not a mirror surface, or an angle other than perpendicular to the element plane S ′ is provided, thereby eliminating excessive reflection and making it clearer. A good image can be obtained. The two mirror surfaces 11 ′ and 12 ′ constituting the two-surface corner reflector 1 ′ can use total reflection or can use reflection by a reflection film. In particular, when the total reflection of the mirror surfaces 11 ′ and 12 ′ is used, it can be expected that multiple reflections are less likely to occur because there is a critical angle for total reflection. Furthermore, it is also possible to attach a metal reflection film to two surfaces of a cylindrical body on which a mirror surface is to be formed, and bond the cylindrical bodies to each other. In this case, it is necessary to take measures against multiple reflections such as non-specularization to a surface other than the mirror surface, but a two-surface corner reflector array having a high aperture ratio and a high transmittance can be obtained.

  In addition, the two specular elements constituting the two-surface corner reflector may be arranged with a gap between each other without being in contact with each other as long as two orthogonal reflecting surfaces can be formed. The specific configuration of each part is not limited to the above-described embodiment, such as the shape of the display optical system or the two-surface corner reflector array can be freely set, and various modifications can be made.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. The basic configuration of the three-dimensional aerial image display device X2 according to the present embodiment uses the real mirror image forming optical system in the first embodiment from the two-surface corner reflector array 2A, the half mirror 5 and the retro reflector array 6. It has a configuration in place of the real mirror image forming optical system 2B. The configurations of the display 3 and the driving means 4 are the same as those in the first embodiment. As shown in FIG. 9, the real mirror image forming optical system 2B applied in the present embodiment is arranged in the space on the lower surface side of the half mirror surface 51 with the half mirror surface 51 of the half mirror 5 as the symmetry plane S2. The image O displayed on the display surface 31 of the display 3 is reflected by the half mirror surface 51, is further retroreflected by the retroreflector array 6, returns to the incident direction, and passes through the half mirror surface 51. The mirror image is imaged as a three-dimensional aerial image P at a plane symmetrical position with respect to the half mirror surface 51 as the symmetry plane S2 of the set over time.

  As the half mirror 5 which is a component of such a real mirror image forming optical system 2B, for example, a thin reflective film coated on one surface of a transparent thin plate such as a 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 P from being doubled. In addition, on the actual upper surface of the half mirror 5, a visual field control film or a visual field is used as a visual line control means that transmits a light beam in a specific direction and blocks a light beam in another specific direction or diffuses only a light beam in a specific direction. An optical film 52 such as a corner adjusting film can be attached and provided. Specifically, the optical film 52 prevents the light directly transmitted through the half mirror 5 from reaching the position other than the viewpoint V2 by the optical film 52, so that the display surface of the display 3 is displayed from other than the viewpoint V2 through the half mirror 5. 3 is prevented from being directly observable, while only being reflected by a half mirror 5 to be described later, retroreflected by a retroreflector array 6, and then transmitting only light rays in a direction that passes through the half mirror 6. Thus, only the stereoscopic aerial video P that is a set of real images of the video O can be observed from the specific viewpoint V2.

  On the other hand, any type of retroreflector array 6 can be applied as long as it strictly reflects back incident light, 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 as shown in FIG. 9, or may be a flat surface. For example, the retroreflector array 6 shown in FIG. 10 (a) 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 the body corner. The individual retro-reflectors 61 form a regular triangle when the mirror surfaces 61a, 61b, 61c forming three isosceles right-angled isosceles triangles are gathered at one point and viewed from the front. The mirror surfaces 61a, 61b, 61c are orthogonal to each other to form a corner cube. In addition, the retroreflector array 6 shown in an enlarged part of the front view in FIG. 5B is also a corner cube array that is a set of corner cubes that use one corner of the body corner. Each retroreflector 61 forms a regular hexagon when the mirror surfaces 61a, 61b, 61c forming three squares of the same shape and the same size are gathered at one point and viewed from the front, and these three mirror surfaces 61a, 61b and 61c are orthogonal to each other. The retroreflector array 6 is different in shape from the retroreflector array 6 shown in FIG. 11A and 11B, the retroreflector array 6 shown in FIGS. 10A and 10B will be described as an example. Light incident on one of the mirror surfaces (for example, 61a) By reflecting on the other mirror surfaces (61b, 61c), the light is reflected in the original direction in which the light has entered the retroreflector 61. The paths of the incident light and the outgoing light with respect to the retroreflector array 6 are not strictly overlapping but are parallel to each other. However, when the retroreflector 61 is sufficiently smaller than the retroreflector array 6, the paths of 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 corner cube array described above, a retroreflector array 6 that retroreflects light rays with three mirror surfaces (“corner reflector” in a broad sense) can be employed. 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) And acute angle retroreflectors having angles of 90 degrees, 60 degrees, and 45 degrees formed by the adjacent mirror surfaces of the three mirror surfaces are suitable as the retroreflective element 3 applied to the present embodiment. In addition, a cat's eye retro reflector or the like can be used as a unit retroreflective element. These retro-reflector arrays may be planar or bent or curved. In the example of FIG. 9, the retroreflector array 6 having a partially spherical shape is arranged outside the display 3, but it is possible to retroreflect light emitted from the image O on the display surface 31 and reflected by the half mirror 5. The shape and arrangement position of the retro reflector array 6 can be set as appropriate.

  Also in the three-dimensional aerial image display device X2 having such a configuration, as in the case of the first embodiment, the actual mirror image imaging optical system 2B always has its actual mirror image at a plane symmetrical position with respect to the symmetry plane S2 of the projection object. Therefore, the display 3 is moved three-dimensionally by the driving means 4 and the image O on the display surface 31 is sequentially changed in accordance with the operation, so that a set of real mirror images of the image O is obtained. The three-dimensional aerial image P can be imaged and observed in the space on the upper surface side of the half mirror 5.

Then , by changing the arrangement configuration of the retroreflector array 6 described above and using the double-sided display 3 ′ having the display surfaces 31 and 31 on both sides described as the first embodiment, the stereoscopic aerial image P can be converted to multiple viewpoints, that is, In the second embodiment of the present invention, the stereoscopic aerial image P as a real mirror image of the image O can be observed from a number of directions at the same time. FIG. 12 is a schematic longitudinal sectional view showing an example of a three-dimensional aerial image display device X2 ′ that realizes multi-viewpoints. In this three-dimensional aerial image display device X2 ′, a real mirror image forming optical system 2B ′ surrounding the double-sided display 3 ′ by a retroreflector array 6 ′ having a hemispherical shape on the lower surface side of the disk-shaped half mirror 5 ′. Is applied. The half mirror 5 ′ is the same as the above-described half mirror 5 except for the shape, and the half mirror surface 51 ′ is a symmetric surface S2 ′. On the upper surface of the half mirror 5 ′, a visual field control film or a viewing angle is used as a line-of-sight control means that transmits a light beam in a specific direction and blocks a light beam in another specific direction or diffuses only a light beam in a specific direction. An optical film 52 ′ such as an adjustment film is attached and provided. On the other hand, the retro-reflector array 6 ′ has a curved shape in which a large number of retro-reflectors 61 are formed on the inner surface side, similar to the above-described retro-reflector array 6. The bottom of the retroreflector array 6 ′, which is directly below the display 3, is not used for retroreflection of light rays. Therefore, the retroreflector 61 is not formed. Absent.

  In this case, light emitted in various directions from the image O displayed on the display surfaces 31 and 31 of the double-sided display 3 ′ is reflected by the half mirror 5 ′, and the retro-reflector array 6 on the lower surface side of the half mirror 5 ′. The image is retroreflected in the same direction at 'and further linearly transmitted through the half mirror 5', thereby forming an image at a plane-symmetrical position in the space above the upper surface of the half mirror 5 '. In addition, since the light which went out directly from the image O and reflected by the half mirror 5 ′ returns to the position of the original image O again, it is not retroreflected by the retroreflector array 6 ′. For this reason, The bottom of the retro reflector array 6 ′ will not be used for retroreflection. Therefore, the stereoscopic aerial image P, which is a set of imaging points, can be observed at the same time as the viewpoints V2 and V2 ′ at least two places on the surface side of the half mirror 5 ′, except just above the image O. Become. In addition, in the image O, light that is directly transmitted without being reflected by the half mirror 5 ′ does not reach the viewpoint by the optical film 52, so that the image O can be directly observed from the viewpoint on the upper surface side of the half mirror 5 ′. Is prevented.

  The real mirror image forming optical system capable of such multi-viewpoints is not limited to the above-described mode, and as long as the projection object is surrounded by the half mirror and the retroreflective element, their shapes and the like are appropriately changed. can do. In addition, in this embodiment, the real mirror image forming optical system is not limited to the above-described embodiment, and various modifications such as the specific configuration and shape of the half mirror and the retroreflector array can be made. Similarly to the case of the first embodiment, the display surface of the display can be directed in the direction of the symmetry plane, and the display can be operated three-dimensionally in the direction perpendicular to the symmetry plane by the driving means 4. In other words, even when the display surface is one surface, observation from multiple viewpoints is possible. However, in this case as well, as in the case described in the first embodiment, since the video on the display surface cannot be changed for each viewpoint, only a stereoscopic stereoscopic image can be displayed.

  <Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIGS. The three-dimensional aerial image display device X3 according to the present embodiment is one in which an afocal lens array 2C is applied as a real mirror image imaging optical system, and the configurations of the display 3 and the driving means 4 are the display 3 in the first embodiment. Is the same as the modified example (see FIG. 7) in which is arranged in parallel with the symmetry plane. As shown in FIG. 14, the afocal lens array 2C is configured by arranging a large number of afocal lenses 7 on one element plane S3. Specifically, the afocal lens 7 includes two lenses 71 and 72 that share an optical axis g perpendicular to the element plane S3 and are spaced from each other by the focal lengths fs and fe. In this example, convex lenses are applied as the lenses 71 and 72. As a result, light incident on the lenses 71 from one side of the element plane S3 is emitted from the other pair of lenses 72, and collected at a position that is plane-symmetric with respect to the element plane S3. Shine. That is, the image O displayed on the display surface 31 of the display 3 serving as a light source forms an image at a plane symmetric position with respect to the element plane S3. Note that when the afocal lens array 2C is used to form a projection object as a real image at a plane symmetric position with respect to the element plane S3, the viewing angle is limited to a direction close to the element plane S3.

Also in the three-dimensional aerial image display device X3 having such a configuration, as in the case of the first embodiment or the second embodiment, the plane of symmetry of the image O displayed on the display surface 31 of the display 3 that is the projection object. Since the real mirror image is always formed at a plane-symmetrical position with respect to the element plane S3, the display 3 is moved three-dimensionally by the driving means 4 and the image O of the display surface 31 is changed in accordance with the operation. , Ri can der be observed by imaging the three-dimensional floating image P as the set of real mirror image of the image O in the upper face side of the space of the afocal lens array 7, both surfaces having a display surface 31, 31 on both sides by using the display 3 ', the third embodiment is Ru configured.

  In addition, this invention is not limited to embodiment mentioned above. In each of the above-described examples, a mode in which a spherical three-dimensional image is formed in the air as a real mirror image based on a circular image whose diameter changes by oscillating (reciprocating) the display by the driving means is described. However, the image displayed on the display surface of the display and the form of the three-dimensional movement of the display by the driving means can be appropriately set. For example, if the display is arranged so that the display surface is parallel to the symmetry plane of the real image imaging optical system, and the display is driven in the normal direction of the symmetry plane by the driving means, only one side facing the symmetry plane side Even if a display having a display surface is used, it is possible to cope with a multi-viewpoint of a stereoscopic aerial image. In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

X1, X1 ′, X1 ″, X2, X2 ′, X3... Volume scanning type three-dimensional aerial image display device S1, S1 ′, S3.
S2 ... Symmetry plane O ... Projected object P ... Solid aerial image 1,1 '... 2 plane corner reflector 2A (2A1,2A2), 2' ... 2 plane corner reflector array (real mirror image imaging optical system)
2B, 2B '... real mirror image forming optical system 2C ... afocal lens array (real mirror image forming optical system)
3, 3 '... Display 4 ... Driving means 5, 5' ... Half mirror 6 ... Retro reflector array 7 ... Afocal lens 31 ... Display surface 51, 51 '... Half mirror surface 61 ... Retro reflector

Claims (5)

A real mirror image forming optical system capable of forming a real image of the projection object as a mirror image at a plane symmetrical position with respect to a certain geometric plane as a symmetry plane;
A display surface that is arranged on the lower surface side of the symmetrical surface and displays an image as the projection object, a display provided on both the front surface and the back surface ;
Drive means for operating the display so as to perform a motion including a component in a direction perpendicular to the display surface;
A volume characterized in that an image displayed on the display surface is changed in synchronism with an operation of the display by the driving means, thereby forming the image as a stereoscopic image in a space on the upper surface side of the symmetry plane. Scanning 3D aerial image display device. The real mirror image forming optical system is a two-surface corner reflector array in which a plurality of two-surface corner reflectors composed of two mirror surfaces perpendicular to each other perpendicular to a predetermined element plane are arranged on the element plane. The volume scanning type three-dimensional aerial image display device according to claim 1, wherein an element plane is the symmetry plane. The real mirror image forming optical system includes a retroreflector array that retroreflects light rays and a half mirror that has a half mirror surface that reflects and transmits light rays, and the half mirror surface is the symmetry surface, 2. The volume scanning type three-dimensional aerial image display device according to claim 1, wherein the retroreflector array is arranged in a space on the same side as the projection object with respect to the half mirror. 4. The volume scanning type three-dimensional aerial image display device according to claim 3, wherein the retro reflector is disposed so as to three-dimensionally surround the display surface of the display together with the half mirror at least on the back surface side of the half mirror. . The real mirror image forming optical system is an afocal lens array in which a plurality of afocal lenses having an optical axis perpendicular to a predetermined element plane are arranged on the element plane, and the element plane is the symmetry plane. The volume scanning type three-dimensional aerial image display device according to claim 1.

Images