JP2017067933A - Two-faced corner reflector array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-faced corner reflector array having many two-faced corner reflectors each having two reflective faces perpendicular to each other in a vertical attitude and forming real mirror images by subjecting light rays from an object of observation to plane-symmetric conversion, capable of reducing stray light that would obstruct observation of real mirror images once for each reflective face, namely twice in total.SOLUTION: A two-faced corner reflector array is so configured that the luminosity of reflected light is enabled to be enhanced twice in relative terms by forming a light shield mask in each of two-faced corner reflectors 2 in an area where reflected light does not pass twice in areas from an incidence port 25 to an emission port 26, and reducing stray light such as the reflected light and directly transmitted light once with reflective faces 21 and 22 instead of reducing the transmissivity of reflected light twice.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a two-sided corner reflector array that uses a two-sided corner reflector that forms a real image of an observation object as a basic component and can reduce stray light.

  The present inventor has so far observed in the air by arranging a real mirror image forming optical system (two-sided corner reflector) that forms a real image of an observation object in a space on the observer side as a basic component. A two-sided corner reflector array has been proposed and developed so that a real image of an object can be formed and observed (see, for example, Patent Document 1). A dihedral corner reflector array is a device in which a large number of small unit optical elements are discretely arranged to finely divide a light beam emitted from an observation object, and geometrically collect the divided light beams to form an image. is there. The image (aerial image) imaged by the two-sided corner reflector array is observed at a position determined in the air regardless of the distance and direction in which the image is observed, and has a presence like an actual object (observation target). It can be seen as being.

  The two-sided corner reflector array is configured as a set of two-sided corner reflectors as unit elements having two orthogonal reflecting surfaces as basic components, and virtually shares a common plane perpendicular to the reflecting surfaces of all unit elements. The element surface is used. Each two-sided corner reflector is configured from the optical point of view as a reflecting surface with two side walls that are perpendicular to each other of optical holes through which light passes.

  Then, when a light beam emitted from an observation object arranged in one space across the element surface is transmitted, the light beam that has entered the optical hole is reflected once by each reflection surface, a total of two times, and optically By emitting from a simple hole, the light beam is subjected to plane symmetry conversion on the element surface. Looking at the entire two-surface corner reflector array, the light beam reflected and emitted twice in each optical hole is imaged in the space on the opposite side of the element surface from the observation target, An observer viewing from an oblique direction can observe a real image as if floating in space. Wear special glasses, etc., so that if the observation target is a planar object or video, a planar real image can be observed, and if the observation target is a stereoscopic object or video, a stereoscopic real image can be observed. As an optical device capable of observing aerial images, the two-surface corner reflector array is epoch-making. The real image formed by the two-surface corner reflector array is imaged as a mirror image at a plane symmetrical position of the observation target with respect to the element surface. According to such a two-surface corner reflector array, there is no chromatic aberration due to the basic imaging principle using reflection by the reflecting surface, and there is a specific focal length because the obtained imaging is a mirror image. In addition, since there is no optical axis as a center, it has various features that an object to be observed at an arbitrary position can be imaged without distortion.

  Although the two-sided corner reflector array has the above-described structural and imaging principle features, several structures are acceptable. Optical holes with two reflecting surfaces perpendicular to each other on the side wall are allowed to have a structure such as a square hole-shaped through-hole or a square columnar block body made of transparent resin as long as the light beam is transmitted. Is done. In this case, as long as only the side walls formed by the two reflecting surfaces maintain a vertical relationship, the shape of the through holes and other parts of the block body is not limited, and for example, the cross-sectional shape in the direction parallel to the element surface is The shape may be a sector shape. In addition, the configuration in which the two reflecting surfaces constituting the two-surface corner reflector are arranged at the same height position is not essential, and the two reflecting surfaces are vertically positioned as long as a perpendicular relationship is maintained. (For example, refer to Patent Document 2), an intermediate structure between them, that is, a configuration in which only a part of the two reflecting surfaces exists at the same height position is also allowed.

Japanese Patent No. 4900618 JP 2009-276699 A

  In such a two-sided corner reflector array, light rays that are reflected and transmitted twice (two times reflected light) once by each of the two reflecting surfaces of each two-sided corner reflector contribute to the imaging of the observation target. However, among the light rays emitted from the object to be observed, the light rays that pass through each of the two-surface corner reflectors are emitted only by being reflected once by one of the reflecting surfaces (one-time reflected light). To do. Since this one-time reflected light is a light beam that undergoes line-symmetrical conversion with respect to the normal of the reflecting surface, it becomes stray light having different characteristics with respect to the two-time reflected light that is the surface-symmetric converted light. In addition, light rays that are directly emitted without being reflected by either reflecting surface (directly transmitted light) are obstructive for observation of image formation by twice reflected light. Accordingly, the one-time reflected light and the directly transmitted light become stray light for the real image to be observed by the two-time reflected light, and thus reduction thereof is desired.

  The present invention mainly focuses on the problems of such a two-surface corner reflector array and provides a two-surface corner reflector array that is devised to reduce stray light caused by one-time reflected light or directly transmitted light as much as possible. It is what.

  That is, the present invention is a two-surface corner reflector array having a configuration in which a plurality of two-surface corner reflectors having two reflecting surfaces arranged in a standing posture are arranged along one plane as unit optical elements, The corner reflector is arranged so that the two reflecting surfaces are perpendicular to each other, and an entrance is formed at the lower end and an exit is formed at the upper end so that light can be transmitted in the vertical direction. , Wherein a light-shielding mask is formed in a region where the twice reflected light that is incident from the incident port and is reflected twice by the two reflecting surfaces once in total, and is emitted from the exit port does not pass through. It is.

  The basic configuration of the two-surface corner reflector array is a set of two-surface corner reflectors which are unit optical elements, and has a configuration in which a large number of two-surface corner reflectors are arranged along one plane. First, the basic configuration and imaging principle of the two-surface corner reflector array and the two-surface corner reflector will be described with reference to FIGS.

  A two-sided corner reflector array 1 illustrated in FIG. 1 has a thin flat plate 10 formed with a large number of rectangular through holes. Each through-hole is a two-surface corner reflector 2 as a unit optical element. As shown in FIGS. 2 and 3, each two-surface corner reflector 2 has two inner walls that are perpendicular to each other, and has a first reflecting surface 21. The second reflecting surface 22 is used. The other two inner walls 23 and 24 are non-reflective surfaces that do not reflect light rays. In this example, a large number of two-surface corner reflectors 2 are arranged in the same direction along a plane 1S that horizontally crosses the thickness direction of the flat plate 10, and this configuration forms the two-surface corner reflector array 1. ing. For convenience of explanation, the plane 1S is illustrated as a plane crossing the central portion in the thickness direction of the flat plate 10, and the plane 1S will be referred to as an “element surface” hereinafter. In each drawing including FIG. 1, the size of each two-sided corner reflector 2 is greatly exaggerated as compared with the two-sided corner reflector array 1.

  In the two-surface corner reflector array 1, the observation object O is disposed obliquely below the flat plate 10 (obliquely below the flat plate 10 toward the inner angle formed by the first reflection surface 21 and the second reflection surface 22 of each two-surface corner reflector 2). In this case, a light beam emitted from the observation object O is transmitted through the two-surface corner reflector array 1 to form an image, and obliquely above the flat plate 10 (the first reflection surface 21 and the second reflection surface 22 of each two-surface corner reflector 2 are The real image P is observed from the viewpoint V of the observer located obliquely above the flat plate 10 toward the inner angle formed. Here, as an example, FIG. 1 shows an observation object O in which an arrow figure displayed on a flat display is adopted, and the arrow figure is observed as a real image P thereof. Specifically, as shown in FIG. 3, a light beam emitted from the observation object O enters from the entrance 25 of each of the two-surface corner reflectors 2 (the incident light is Lin), and the first reflecting surface 21 and the first reflecting surface 21. The two reflecting surfaces 22 are each reflected once twice in total and emitted from the emission port 26 (emitted light is referred to as “Lou”). The real mirror image P is formed at the symmetrical position and is observed from the viewpoint V.

  Next, the principle of image formation by the two-surface corner reflector array 1 will be described. 4 and 5 (FIG. 4 (a) is a schematic projection view in which the second reflecting surface 22 is viewed from the side, and FIG. 4 (b) corresponds to FIG. 4 (a) in which the exit 26 is viewed from the top. 5A is a schematic projection view of the first reflecting surface 21 viewed from the side, and FIG. 5B is a view of the exit 26 facing the view from above. As shown in the corresponding schematic projection view.), The two-surface corner reflector 2 is extracted and shown, and the light rays emitted from the observation object O are incident from the entrance 25 set at the lower end of the two-surface corner reflector 2. The light enters the inside of the surface corner reflector 2, is reflected for the first time at a point (reflection point) r 1 on the first reflection surface 21, and is reflected for the second time at a point (reflection point) r 2 on the second reflection surface 22, The light exits from the exit 26 set at the upper end of the two-surface corner reflector 2 (the optical path of this light beam). Indicated by the one-dot chain line.). Alternatively, the light beam emitted from the observation object O enters the inside of the two-surface corner reflector 2 from the incident port 25, is reflected for the first time at the point (reflection point) r3 on the second reflection surface 22, and the first reflection surface. The light is reflected at a point (reflection point) r4 at 21 for the second time and emitted from an emission port 26 set at the upper end of the two-surface corner reflector 2 (the optical path of this light beam is indicated by a two-dot chain line). As can be understood from FIGS. 4A and 5A, the points r1 and r2 are set for the light rays that are reflected for the first time by the first reflecting surface 21 and for the second time by the second reflecting surface 22. The reflection occurs twice in the plane F1 perpendicular to the paper surface, and the light beam that is reflected for the first time by the second reflection surface 22 and for the second reflection by the first reflection surface 21 Two reflections occur in a plane F2 that passes through r3 and r4 and is perpendicular to the paper surface. As a result of such double reflection of the light beam by the first reflection surface 21 and the second reflection surface 22 in each of the two-surface corner reflectors 2, as a set of the two-time reflection light, the observation surface O of the observation object O with respect to the element surface 1 </ b> S. A real image P is formed as a mirror image (referred to as a real mirror image) at a plane symmetric position, and is observed from an obliquely upper viewpoint V. That is, the light beam emitted from the observation object O is reflected and transmitted twice in the two-surface corner reflector array 1, and is converted into a plane symmetry on the element surface 1 S to form an image as a real mirror image P and observed. It will be. It should be noted that the thickness of the flat plate 10 (for example, 50 to 1000 μm, about 300 μm in this example) is negligibly small with respect to the optical path length (imaging distance) from the observation object O to the real mirror image P. Therefore, from a macro viewpoint, it can be said that the light beam from the observation object O is plane-symmetrically transformed at the element surface S1 and emitted, and is observed from the viewpoint V as the formed real mirror image P.

  By the way, as shown in FIG.4 and FIG.5, in the light ray which injects into the two-surface corner reflector 2 from the entrance 25, either the 1st reflective surface 21 or the 2nd reflective surface 22 reflects only once. One-time reflected light exits from the exit port 26. In the illustrated example, the optical path of the one-time reflected light is indicated by a broken line, the reflection point on the second reflection surface 22 is indicated by a point r5, and the reflection point on the first reflection surface 21 is indicated by a point r6. Such one-time reflected light becomes stray light and causes a reduction in the sharpness and brightness of the real mirror image P formed by the two-time reflected light. Therefore, it is possible to shield the reflected light as much as possible. This is desirable.

  On the other hand, regarding each of the two-surface corner reflectors 2, FIG. 6A (a) is a schematic projection view of the second reflection surface 22 from the side, and FIG. 6B is the first reflection surface 21 from the side. As shown in FIG. 2, a schematic projection view of the first and second reflection surfaces.), The light is emitted from the observation object O and is incident on the incident port 25, and is reflected twice by the first reflecting surface 21 and the second reflecting surface 22 once. There is a region where the twice reflected light cannot pass. In the projection view of FIG. 2A, two diagonal lines d1 connecting the end edge of the entrance port 25 and the end edge of the exit port 26 of the two-surface corner reflector 2 projected in plane and shown in a rectangle are shown. Among the areas defined by d2, the light ray reflected by the first reflecting surface 21 passes through the isosceles triangular area N1 (shown by gray shading) near the right side (inner wall 23) in FIG. This is an area that cannot be obtained. Similarly, with reference to the projection view of FIG. 5B, two diagonal lines d3 connecting the edge of the entrance 25 and the edge of the exit 26 of the two-face corner reflector 2 projected in plan and shown in a rectangle. , D4, the isosceles triangle region N2 (shown by gray shading) near the left side (inner wall 24) in FIG. 4B passes the light reflected by the second reflecting surface 22. This is an area that cannot be done. In other words, since the twice reflected light is reflected by both the first reflecting surface 21 and the second reflecting surface 22, the shaded areas in the internal space of the two-surface corner reflector 2 are shaded in FIGS. A region excluding both of the attached regions N1 and N2 is a region through which reflected light can pass twice. In the case of this example, the two-surface corner reflector 2 as a solid indicated by a rectangular parallelepiped will be described. A solid made by a light ray that enters from the entrance 25 and reaches the first reflecting surface 21 and the first reflecting surface 21 are reflected and emitted. The solid union formed by the light rays emitted from the mouth 26, the solid produced by the light rays incident from the entrance port 25 and reaching the second reflecting surface 22, and the light rays reflected by the second reflecting surface 22 and emitted from the exit port 26 are obtained. The product set (see the solid abcdmonleftgh shown in FIG. 11) with the union of the solids to be created is a region where the reflected light can pass twice, and the region other than the product set cannot pass the reflected light twice. It is an area. However, in the above description, the region where the twice reflected light cannot pass is for all the light rays that can be reflected twice, and in fact, the arrangement position of the two-surface corner reflector 2, the observation object O, and the viewpoint V. Depending on the relationship, only some of these rays are used for observation. In addition, although the region where the reflected light can pass twice and the region where it cannot pass are different depending on the shape of the two-sided corner reflector 2, the case where each two-sided corner reflector 2 has a rectangular parallelepiped shape for convenience of explanation here. This is just an example.

  Therefore, the present invention provides a light-shielding mask for blocking the passage of light in part or all of the areas N1 and N2 (generally denoted by reference numeral N) where the reflected light does not pass twice in the two-surface corner reflector 2. Is going to form. If a light-shielding mask is formed even in a part of the region N where the reflected light does not pass twice, the light is incident from the entrance 25 of each of the two-surface corner reflectors 2 and is either 1 on the first reflecting surface 21 or the second reflecting surface. One-time reflected light that is reflected once and exits from the exit port 26, or directly transmitted light that enters the entrance port 25 and exits from the exit port 26 without being reflected by either the first reflecting surface 21 or the second reflecting surface 22. Among them, since the light beam originally passing through the portion where the light shielding mask exists can be shielded, stray light caused by the reflected light or the directly transmitted light can be reduced correspondingly. Specifically, when the light shielding mask is formed in the region N1, the light beam reflected only once at the point r5 of the second reflecting surface 22 can be shielded, and when the light shielding mask is formed in the region N2, the first reflection is performed. A light beam reflected only once at the point r6 on the surface 21 can be shielded. In addition, since the image formation by the twice reflected light is not hindered by the light shielding mask, the real mirror image P of the observation object O that has been imaged does not have a defect and the luminance is reduced, and the reflected light can be reflected once or directly. Only stray light such as transmitted light can be reduced. In forming the light-shielding mask, various means such as application of translucent ink, formation of a translucent area by processing of the member surface by etching, etc., arrangement of a translucent sheet or block body, etc. Can be selectively used, and the light-impermeable portion formed in this manner can be used as a light-shielding mask.

  In particular, in the case of the two-surface corner reflector array 1 in which the light-shielding mask is formed at a position where the region N where the reflected light does not pass twice is completely shielded, while satisfying the condition of maximally transmitting the reflected light twice, Since the transmission of the once reflected light and the directly transmitted light can be suppressed to the maximum, the clearest real mirror image P can be observed.

  In addition, in the region from the entrance to the exit of each two-sided corner reflector, the inner peripheral surface excluding the two reflecting surfaces is a non-reflecting surface, thereby reducing stray light due to light rays other than the twice reflected light. This contributes to improving the clarity and brightness of the observed real mirror image P.

  In the two-surface corner reflector array according to the present invention, the light incident from the entrance of each two-surface corner reflector is reflected once by the two reflecting surfaces of the two-surface corner reflector that are perpendicular to each other, twice in total. In this way, a real mirror image is formed by plane-symmetrical conversion of the light beam emitted from the observation object, and as a result, the image can be observed, but the light beam incident on each two-surface corner reflector. Among them, a light shielding mask is formed in an area where the reflected light does not pass twice. With this configuration, the light-shielding mask reflects the light only on one of the two reflective surfaces of each of the two-sided corner reflectors without being disturbed by the light-shielding mask. In order to block a part of the reflected light and the directly transmitted light that is not reflected by either reflecting surface and is transmitted through the two-surface corner reflector, the ratio of the twice-reflected light to the light transmitted through the two-surface corner reflector is relative. As a result, it is possible to observe a real mirror image in which stray light is reduced as compared with a conventional two-sided corner reflector array without a light shielding mask.

The typical perspective view showing the example of basic composition of the 2nd page corner reflector array concerning the present invention. The top view which expands and schematically shows a part of the same 2 side corner reflector array. The typical perspective view which shows the mode of the twice reflection of a light beam by extracting the single 2 surface corner reflector in the 2 surface corner reflector array. (A) The projection figure which shows the mode of the reflection of the light ray in the same 2 side corner reflector, seeing a 2nd reflective surface from the side, and facing. (B) The top view which shows typically the mode of the reflection of the light beam in a 2 surface corner reflector. (A) The projection figure which shows the mode of the reflection of the light beam in the same 2 side corner reflector, seeing the 1st reflective surface from the side, and facing. (B) The top view which shows typically the mode of the reflection of the light beam in the 2nd surface corner reflector. (A) The projection figure which shows the mode of the reflection of the light beam in the same 2 side corner reflector together with the area | region which 2nd reflected light cannot pass, and the 2nd reflective surface from the side facing directly. (B) The projection figure which shows typically the state of the reflection of the light beam in the same 2 side corner reflector by facing the 1st reflective surface from the side with the area | region which 2 times reflected light cannot pass through. The partial expansion perspective view which shows typically the 2 surface corner reflector array which concerns on one Embodiment of this invention. The partial enlarged plan view which shows a two-plane corner reflector array typically. The typical perspective view which shows the mode of the reflection of a light beam by extracting the single 2 surface corner reflector in the 2 surface corner reflector array. The typical perspective view which decomposes | disassembles and shows the same 2 surface corner reflector array. The typical perspective view which shows the other single 2 surface corner reflector applicable to the same 2 surface corner reflector array. The partial expansion perspective view which shows typically the other 2 surface corner reflector array in the same embodiment. (A) The projection figure which shows the mode of the reflection of a light beam by extracting the single 2 surface corner reflector in the 2 surface corner reflector array, and seeing the 1st reflective surface from the side facing. (B) The top view which shows typically the mode of the reflection of the light beam in the 2nd surface corner reflector. (A) The projection figure which typically shows the state of reflection of a light beam by extracting a single two-surface corner reflector in the two-surface corner reflector array, with the second reflection surface facing from the side. (B) The top view which shows typically the mode of the reflection of the light beam in the 2nd surface corner reflector.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The two-surface corner reflector array 1 according to the present embodiment has the basic configuration and the imaging principle shown in FIGS. 1 to 5, and reflects twice in each two-surface corner reflector 2 as shown in FIG. 6. A light shielding mask M is formed in a region N where light is not transmitted. FIG. 7 (schematic partial perspective perspective view) and FIG. 8 (schematic plan view) are schematic views of some of the two-sided corner reflectors 2 extracted from the entire two-sided corner reflector array 1 of the present embodiment. FIG. 9 shows a schematic diagram obtained by extracting the single two-surface corner reflector 2. Each of the two-surface corner reflectors 2 in the two-surface corner reflector array 1 has a square incident port 25 and an emission port 26 each having the same dimension as the height dimension h (300 μm in this example) of the flat plate 10. Are formed from a hollow hole (refractive index 1) of a physical / optical cubic shape formed on the bottom surface and the top surface of the first reflecting surface 21. The second reflection surface 22 is used, and the two inner walls 23 and 24 facing the first reflection surface 21 and the second reflection surface 22 are non-reflection surfaces. Of the horizontal plane that crosses the two-surface corner reflector 2, that is, the plane that intersects perpendicularly to the first reflecting surface 21 and the second reflecting surface 22, the surface that intersects the center in the height direction (in the same plane as the element surface 1S), It is set as the element surface 1S of the two-surface corner reflector array 1. The two-surface corner reflector array 1 is formed by forming a large number of two-surface corner reflectors 2 formed of such holes on the flat plate 10.

  In the present embodiment, an L-shape in plan view is formed at the center in the height direction of each two-surface corner reflector 2 so as to avoid the inner corner formed by the first reflecting surface 21 and the second reflecting surface 22. The light shielding mask M is formed horizontally. The light shielding mask M is formed over the entire width dimension of the inner walls 23 and 24, and is formed over exactly half of the width dimension of the first reflecting surface 21 and the second reflecting surface 22. Assuming that the two-surface corner reflector 2 is cut horizontally at the height position of the light shielding mask M, the first reflection surface 21 and the second reflection surface 22 of the two-surface corner reflector 2 are adjacent to each other at this height position. Only the matching inner corner is opened in a square shape. In such a light shielding mask M, the twice reflected light does not pass so as to completely shield the entire region N (N1, N2) where the twice reflected light shown in FIG. 6 does not pass through the two-surface corner reflector 2. The region N is formed at the center in the height direction of the two-surface corner reflector 2 having the maximum horizontal dimension.

  As shown in FIG. 9, each vertex of the two-surface corner reflector 2 will be described with the symbols a, b, c, d, e, f, g, h, and the entrance 25 is formed by a square abcd. The exit 26 is formed by a square efgh. The midpoints of the sides ae, bf, cg, dh are i, j, k, l, the midpoint of the line segment il is m, the midpoint of the line segment kl is n, and the intersection of the horizontal diagonal lines ik and jl is o In this case, the light shielding mask M has a horizontal L shape surrounded by the point ijknom. Of the light rays (incident light Lin) that enter the two-surface corner reflector 2 from the incident port 25, the light is reflected by the second reflecting surface 22 (in-plane point r3) and reflected by the first reflecting surface 21 (in-plane point r4). Thus, the light beam (emitted light Lout) emitted from the emission port 26 passes through the quarter surface lmon in the area of the surface ijkl that horizontally traverses the two-surface corner reflector 2. Similarly, the light beam reflected by the first reflecting surface 21 and reflected by the second reflecting surface 22 and exiting from the exit port 26 always passes through the surface lmon. From the above, the light shielding rate of the twice reflected light by the light shielding mask M is zero. On the other hand, the first reflected light that is incident on the incident port 25 and is reflected by either the first reflecting surface 21 or the second reflecting surface 22 and is emitted from the emitted light 26 or the first reflected light that is incident from the incident port 25. A part of the directly transmitted light that is emitted from the emitted light 26 without being reflected by the surface 21 and the second reflecting surface 22 is transmitted through the surface lmon, but a part of the once reflected light and the directly transmitted light is shielded by the light shielding mask M. Therefore, the transmittance of the once reflected light or the directly transmitted light is reduced to about half. For this reason, the brightness of the twice reflected light that forms the real mirror image P observed from the viewpoint V after the light beam emitted from the observation object O is plane-symmetrically converted by the two-surface corner reflector array 1 is relatively high. Therefore, the clearness of the real mirror image P is improved as compared with the case where the light shielding mask M is not provided.

  The two-sided corner reflector array 1 provided with such a light shielding mask M is manufactured, for example, as follows. First, as shown in FIG. 10 corresponding to FIG. 8, two congruent two-sided corner reflector arrays 1 </ b> A and 1 </ b> B whose height dimension is half that of the two-sided corner reflector array 1 of FIG. 1 are manufactured. Corresponding to the two-surface corner reflector array 1, the two-surface corner reflector array 1A has a large number of two-surface corner reflectors 2A (first reflecting surface 21A, second reflecting surface 22A), and the two-surface corner reflector array 1B. Has a number of two-surface corner reflectors 2B (first reflecting surface 21B, second reflecting surface 22B). For example, the following method can be used to manufacture the two-sided corner reflector arrays 1A and 1B. First, metal molds corresponding to the flat plates 10A and 10B (thickness of the flat plate 10 are half) constituting the two-sided corner reflector arrays 1A and 1B are created. Since the two-sided corner reflector arrays 1A and 1B are congruent, only one mold is sufficient. Then, the mirror surface is formed by subjecting the surface on which the first reflecting surface 21A and the second reflecting surface 22A (or the first reflecting surface 21B and the second reflecting surface 22B) are to be formed to a nano-scale cutting process. These surface roughnesses are set to 10 nm or less so as to have a uniform mirror surface with respect to the visible light spectrum region. Specifically, in the present embodiment, the first reflecting surface 21 and the second reflecting surface 22 constituting the two-surface corner reflector 2 are 150 μm in height corresponding to the thickness of the two-surface corner reflector arrays 1A and 1B, The width is 300 μm corresponding to one side of the emitted light 26, and a plurality of plates are formed at a predetermined pitch on each flat plate by a nanoimprint method or an electroforming method in which the press method using the previously created mold is applied to the nanoscale. Become. In the present embodiment, all the two-surface corner reflectors 2A and 2B are arranged on regular lattice points so as to face the same direction. In addition, an aperture ratio can be raised and the transmittance | permeability of a light ray can be improved by setting the space | interval dimension of 2B corner reflectors 2A adjacent and 2B as small as possible. Then, in the flat plate, in portions other than the portions where the first reflecting surface 21B and the second reflecting surface 22B of the two-sided corner reflector 2B are formed, the first reflecting surface 21A and the second reflecting surface 22A of the two-sided corner reflector 2A. Performs a shading process. In this embodiment, the two-surface corner reflector arrays 1A and 1B are formed by providing tens of thousands to several hundreds of thousands of such two-surface corner reflectors 2A and 2B on each flat plate. In addition, when a flat plate is formed with a metal such as aluminum or nickel by an electroforming method, each of the reflecting surfaces 21A, 22A, 21B, and 22B naturally becomes a mirror surface if the surface roughness of the mold is sufficiently small. Further, when the flat plate is made of resin or the like by using the nanoimprint method, it is necessary to perform mirror coating by sputtering or the like in order to create the reflecting surfaces 21A, 22A, 21B, and 22B.

  Then, the two two-sided corner reflector arrays 1A and 1B manufactured in this way are bonded or pressure-bonded by sandwiching a thin film F in which a large number of light-shielding masks M are formed between them and overlapping them vertically. A two-sided corner reflector array 1 as shown in FIG. 8 is manufactured. The thin film F can be manufactured by a method such as printing a large number of L-shaped shapes at a predetermined pitch with a light-shielding paint or the like on a portion where the light-shielding mask M is to be formed. In the two-surface corner reflector array 1 including the two-surface corner reflector arrays 1A and 1B, the first mirror surface 21A and the first mirror surface 21B form the first mirror surface 21 when the two-surface corner reflectors 2A and 2B are continuous in the vertical direction. The second mirror surface 22 is formed by the two mirror surfaces 22A and 22B. Then, the light shielding mask M in each of the two-surface corner reflectors 2 is formed just at the position that becomes the element surface 1S.

  The two-sided corner reflector array having a two-sided corner reflector having a hollow inside has been described above, but the two-sided corner reflector array having a two-sided corner reflector made of an optical hole although not physically having a hole. It is also possible. In this case, for example, a structure in which a large number of two-face corner reflectors are embedded inside a flat plate made of transparent resin, glass, or the like can be used. As a specific manufacturing method, for example, a transparent thin plate having a thickness of 0.3 mm and a reflective film formed on one side are laminated and bonded, and then sliced to a thickness of about 0.4 mm in a direction perpendicular to the laminated surface. . By mirror-polishing both surfaces of the sliced thin plate, a slit mirror array in which thin plate mirrors having a thickness of 0.3 mm between mirrors having a thickness of 0.3 mm are arranged. A reflective film is further formed on one surface of the slit mirror array and laminated in the same direction, and then sliced to a thickness of about 0.4 mm in a direction perpendicular to the laminated surface and the slit mirror. A two-sided corner reflector array having a thickness of 0.3 mm can be manufactured by mirror-polishing both surfaces of the sliced thin plate. When two two-sided corner reflector arrays prepared in this way are prepared and stacked one above the other, either the bottom surface of the upper two-sided corner reflector array or the upper surface of the lower-side two-sided corner reflector array is etched or A light-shielding mask similar to the above can be formed by forming a light-shielding mask using a pattern forming technique such as printing, aligning the upper and lower two-surface corner reflectors, and bonding or pressure-bonding the two sheets. Is obtained. For example, if the refractive index of a flat plate material is about 1.5, a two-sided corner reflector array having the same length and thickness of one side of the entrance and the emitted light can be produced and superimposed to obtain an appropriate view. The maximum transmittance of the reflected light twice can be maximized in the region.

  The light shielding mask M is not limited to a planar one, but may be a three-dimensional one. For example, in FIG. 11, when a single two-surface corner reflector 2 (the symbol is the same as that in FIG. 9) is extracted and shown corresponding to FIG. 9, the two-surface corner reflector 2 represents the two-surface corner reflector 2. Inside the cube abcdefgh to be formed, there is a light shielding mask M protruding so as to leave an intermediate opening monl inward from the entrance 25 and the outgoing light 26. Such a shape can be produced by transfer using a mold. For example, a die for releasing the quadrangular frustum abcdmon downward from a mold for forming the flat plate 10 and a square frustum efghmonl are provided. It is obtained by pulling out the respective punches that release upward. The surfaces abom, bcno, efom, and fgno can be effectively used as a drawing taper at the time of mold release. A reflective film is formed on the first reflective surface 21 and the second reflective surface 22 to function as a reflective surface. Further, it is desirable that the surfaces abom, bcno, efom, and fgno be subjected to non-reflective and opaque processing. In this case, these surfaces abom, bcno, efom, fgno constitute a light shielding mask M. Even in each of the two-sided corner reflector arrays manufactured in this way, each two-sided corner reflector 2 transmits the reflected light twice at the maximum with a light shielding rate of zero, while most of the reflected light and the directly transmitted light are the most. Since the light is shielded by the three-dimensional light shielding mask M, a clear real mirror image P can be observed in the same manner as the two-surface corner reflector array 1 having the planar light shielding mask M.

  Moreover, the 1st reflective surface and 2nd reflective surface which comprise a 2 surface corner reflector may be arrange | positioned in a different height position. For example, a two-sided corner reflector array 100 shown in FIG. 12 is composed of a large number of thin plate-like mirrors 110. The mirror 110 has one surface as a reflecting surface and the other portions as non-reflecting surfaces. The two-sided corner reflector array 100 is formed by stacking up and down in a posture in which the reflecting surface is raised. Is configured. The plurality of mirrors 110 in the lower stage 110A are arranged at a predetermined pitch with the reflecting surface 121 facing in the same direction, and the plurality of mirrors 110 in the upper stage 110B change the direction around the vertical axis by 90 degrees. The mirrors 110 are arranged at a predetermined pitch with the reflecting surface 122 facing in the same direction. With this configuration, a large number of square-shaped spaces communicating in the vertical direction are formed in alignment, and each of these spaces constitutes a two-sided corner reflector 200. That is, in each double-sided corner reflector 200, as shown in FIGS. 13 and 14 corresponding to FIGS. 4 and 5, the reflecting surface 121 of the mirror 110 in the lower stage 110A becomes the first reflecting surface, and the mirror 110 in the upper stage 110B. The reflection surface 122 becomes the second reflection surface. The opening at the lower end of each of the two-surface corner reflectors 200 becomes the entrance 125, and the opening at the upper end becomes the exit 126 (see FIG. 13).

  Here, FIG. 13A is a schematic projection view in which the second reflecting surface 122 is viewed from the side, and FIG. 13B is a schematic view corresponding to FIG. 13A in which the exit 126 is viewed from the top. Projection view. FIG. 14A is a schematic projection view in which the first reflecting surface 121 is viewed from the side, and FIG. 14B is a schematic projection view corresponding to FIG. 14A in which the exit 126 is viewed from the top. It is. A light beam emitted from the observation object O (omitted in the figure) enters the inside of the two-surface corner reflector 200 from the entrance 125 set at the lower end of the two-surface corner reflector 200, and a point (reflection) on the first reflecting surface 121. (Point) the first reflection at r101, the second reflection at point (reflection point) r102 on the second reflection surface 122, and the emission from the exit 126 set at the upper end of the two-surface corner reflector 200 (this) The optical path of the light beam is indicated by a one-dot chain line). Alternatively, the light beam emitted from the observation object O enters the inside of the two-surface corner reflector 200 from the incident port 125, and is reflected at the point (reflection point) r103 on the first reflection surface 121 for the first time, and the second reflection surface The second reflection is performed at a point (reflection point) r104 at 122 and the light is emitted from the emission port 126 (the optical path of this light beam is indicated by a two-dot chain line). The optical path of the one-time reflected light is indicated by a broken line, the reflection point on the second reflection surface 122 is indicated by a point r105, and the reflection point on the first reflection surface 121 is indicated by a point r106. When considered similarly to the two-surface corner reflector 2 shown in FIGS. 4 and 5, the two-surface corner reflector 200 having the first reflection surface 121 and the second reflection surface 122 whose height positions are different in the vertical direction is also twice. Only the reflected light is plane-symmetrically converted by passing through the two-sided corner reflector 200, and forms a real mirror image P (not shown in the figure), but of the internal space of the two-sided corner reflector 2, There are still areas (N101 and N102 indicated by gray shading) where the reflected light cannot pass twice. By forming a light-shielding mask similar to that of the two-surface corner reflector 2 in this region, that is, by forming a light-shielding mask in the region N101, it is possible to shield light rays that should be reflected once (point r105) by the second reflecting surface 122. By forming a light shielding mask in the region N102, the light beam reflected once (point r106) by the first reflecting surface 121 can be shielded. That is, it is possible to reduce the once reflected light and the directly transmitted light without blocking the twice reflected light. In the case of this example, if the same mirror is applied to all the mirrors 110 in the lower stage 110A and the upper stage 110B, the element surface 100S may be grasped as a horizontal plane passing through the boundary between the lower stage 110A and the upper stage 110B.

  In addition, an intermediate one between the two-surface corner reflector 2 and the two-surface corner reflector 200, that is, the lower first reflection surface and the upper second reflection surface are partially at the same height position. Even in a configuration in which a vertical shift occurs, a two-sided corner reflector array can be formed in the same manner as described above. Even in such a two-sided corner reflector array that is a set of two-sided corner reflectors, there is a region in which the two-time reflected light cannot pass as a sum set of regions in which each one-time reflected light cannot pass. If an appropriate light shielding mask is formed in a region where the twice reflected light cannot pass, the once reflected light and the directly transmitted light can be reduced, and the transmittance of the twice reflected light can be increased.

  In any of the above-described two-surface corner reflector arrays, how much one-time reflected light or direct light is transmitted changes depending on the positional relationship between the two-surface corner reflector array, the observation target, and the observer's viewpoint. Even in the same two-sided corner reflector array, the light shielding rate with respect to one-time reflected light or directly transmitted light by the light shielding mask is not constant. However, no matter what position the observation object is placed with respect to the two-sided corner reflector array within the range in which a real mirror image can be imaged by the two-sided corner reflector array, the twice reflected light that contributes to the imaging is generated. Since the region that cannot pass is uniquely determined by the configuration and shape of each two-sided corner reflector, the relative brightness of the twice reflected light is always improved by forming a light shielding mask. Therefore, in the present invention, the first reflecting surface and the second reflecting surface maintain a vertical relationship, and the condition that the light incident from the incident port is reflected twice and emitted from the output port is satisfied. For example, the shape and configuration of the two-sided corner reflector including the shape of each reflecting surface are not limited to the above-described examples.

  Further, the light shielding mask may be configured to shield the entire region where the twice reflected light cannot pass or may partially shield the region where the twice reflected light cannot pass. 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.

  INDUSTRIAL APPLICABILITY The present invention can be used as an optical element applied to a display device such as a display that can display a clearer and clearer image in the air.

DESCRIPTION OF SYMBOLS 1,100 ... Two-surface corner reflector array 1S, 100S ... Element surface 2,200 ... Two-surface corner reflector 21, 121 ... First reflective surface 22, 122 ... Second reflective surface 25, 125 ... Incident aperture 26, 126 ... Emission Mouth O ... Observation object P ... Image (actual mirror image)
V ... Viewpoint

Claims (3)

A two-surface corner reflector array having a configuration in which a plurality of two-surface corner reflectors having two reflecting surfaces arranged in a standing posture are arranged as a unit optical element along one plane,
Each of the two-surface corner reflectors is disposed so that the two reflecting surfaces are perpendicular to each other, and an entrance is formed at the lower end and an exit is formed at the upper end so that light can be transmitted in the vertical direction.
In each of the two-sided corner reflectors, a light-shielding mask is formed in a region where the twice reflected light that is incident from the incident port and reflected by the two reflecting surfaces once and total two times and does not pass through the exit port. A two-sided corner reflector array characterized in that 2. The two-surface corner reflector array according to claim 1, wherein the light-shielding mask is formed at a position where the region where the twice reflected light does not pass is completely shielded. 3. The two surfaces according to claim 1, wherein an inner peripheral surface excluding the two reflecting surfaces is a non-reflecting surface in a region from the entrance to the exit of each of the two-surface corner reflectors. Corner reflector array.

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