JP5283041B2 - Optical element and display system - Google Patents

Description

  The present invention relates to an optical element and a display system.

  A transmissive optical element having a micromirror capable of forming a mirror image formed as a virtual image in a mirror, that is, an image formed at a plane-symmetric position as a real image in space, has already been proposed (Patent Literature). 1). By using this optical element, it is possible to create an aerial image (real image) having no distortion on the element at a close distance to the observer.

  Specifically, as shown in FIG. 5, the optical element X ′ has a micromirror array structure in which a large number of two-surface corner reflectors 20 ′ (hereinafter sometimes referred to as “micromirrors 20 ′”) are arranged in a matrix. . Each of the micromirrors 20 ′ is composed of two minute mirror surfaces 21 ′ and 22 ′ orthogonal to each other, and is erected vertically with respect to the element surface S ′.

  Thereby, in the optical element X ′, the in-plane direction component with respect to the element surface S ′ of the incident light on each micromirror 20 ′ is retroreflected, and the vertical direction component of the incident light with respect to the element surface S ′ is transmitted as it is. Have plane-symmetric imaging characteristics. Therefore, in the optical element X ′, the real image of the projection object O arranged in the space on the back surface side of the element surface S ′ is in a plane-symmetrical position with respect to the element surface S ′ in the space on the surface side of the element surface S ′. And has an effect of forming an image as a mirror image P (aerial image P).

WO2007 / 116639 pamphlet

  By the way, the resolution of the mirror image P produced by the optical element X ′ is governed by the size of the minute micromirror 20 ′ in the element surface S ′. If the micromirror 20 'is made small, it can be focused on a small spot in terms of geometric optics, but if it is too small, the resolution deteriorates due to the influence of diffraction. Therefore, the dimension of the micromirror 20 ′ has an optimum value from the viewpoint of increasing the resolution of the mirror image P. In this case, in the region between the micromirrors 20 ', there is a dead space having no optical function, and effective use of such a dead space is desired.

  The present invention has been made in view of such circumstances, and provides an optical element that can effectively use a dead space between micromirrors capable of forming an aerial image, and a display system including the optical element. For the purpose.

  The inventors of the present invention thought that it would be advantageous to improve the expressiveness of the image if a plane image related to the aerial image could be projected onto the dead space between the micromirrors. For example, when creating a three-dimensional human image in the space on the substrate that constitutes the element surface, if two-dimensional shadows of this human image are simultaneously displayed in the dead space on the surface of the substrate, it is compared with conventional optical elements. And you can reproduce the images that are rich in reality.

The present invention has been devised for the first time based on such knowledge, and includes a first region and a second region having different light reflection characteristics, and a substrate partitioned by the first region and the second region. wherein the first region is a region where the light of specular reflection by one or more reflecting surfaces to upright the element surface occurs, the second region, diffused reflection of light by the element plane and parallel reflecting surfaces region der which occurs is, when viewed in plan the element surface, rectangular first regions are arranged interspersed in an island shape, and the second region, the periphery of each of the first region Surrounding, each reflective surface of the first region is provided on an inner wall surface of a rectangular optical hole formed perpendicular to the substrate, and the reflective surface of the second region is the substrate other than the hole Provided is an optical element provided over the entire surface .

In addition, the present invention includes a first region and a second region having different light reflection characteristics, and the first region is a region where specular reflection of light is caused by one or more reflection surfaces standing on the element surface. The second region includes: an optical element that is a region in which irregular reflection of light occurs by a reflecting surface parallel to the element surface; and a projector that irradiates image light toward the surface of the optical element. When the light emitted from the projection object arranged in the space on the back surface side of the light passes through the element surface, the surface of the optical element on the surface side of the optical element is reflected by the specular reflection of the light in the first region. Provided is a display system capable of forming a real image of a projection object and projecting a planar image related to the real image of the projection object onto the second area by irregular reflection of the image light in the second area.

  Here, the second area functions as a screen area for projecting the planar image.

  With the above configuration, the display system of the present invention is beneficial in improving the expressiveness of video. For example, when a three-dimensional human image is created in the space by the first region, if a two-dimensional shadow of this human image is displayed simultaneously in the second region (screen region), it is more realistic than a conventional optical element. Can reproduce rich images.

  ADVANTAGE OF THE INVENTION According to this invention, the optical element which can utilize effectively the dead space between the micromirrors which can form an aerial image, and a display system provided with this optical element are obtained.

1 is a perspective view schematically showing an overall configuration of a display system according to an embodiment of the present invention. It is an expansion perspective view in the board | substrate edge part of the optical element of FIG. It is an enlarged view of the element surface in the board | substrate edge part of the optical element of FIG. It is an expansion perspective view in the board | substrate edge part of the optical element by the modification of this invention. It is the perspective view which showed typically the optical system containing the conventional optical element.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view schematically showing the overall configuration of a display system according to an embodiment of the present invention. FIG. 2 is an enlarged perspective view of the optical element of FIG. 1 at the substrate end.

  As shown in FIG. 1, the display system 100 of this embodiment includes an optical element X.

  As shown in FIG. 2, the substrate 10 constituting the optical element X is partitioned by a micromirror region S1 (first region) and a screen region S2 (second region).

  First, the configuration and function of the micromirror region S1 will be described.

  In the substrate 10 of the optical element X, two-surface corner reflectors 20 (hereinafter sometimes referred to as “micromirrors 20”) are arranged with a high density for each of a large number of micromirror regions S1 scattered in an island shape. Yes.

  Each of these micro mirrors 20 functions as a micro optical element (unit optical element), and is emitted from an object to be projected O arranged in the space on the back side of the optical element X as shown in FIG. When the light 200 passes through the element surface S of the optical element X, the real image of the projection object O in the space on the surface side of the optical element X (by the specular reflection of the light 200 by each micromirror 20 in the micromirror region S1 ( A mirror image P) can be formed (details will be described later).

  In this specification, as shown in FIG. 2, a plane that passes through the central portion of the thickness of the thin sheet-like substrate 10 and is parallel to the main surface of the substrate 10 (in other words, a micromirror 20 is formed later). Are defined as “element surfaces S” for the sake of convenience, but such element surfaces S do not exist in the product that embodies the present technology, but are only virtual surfaces. Not too much. However, if the element surface S is selected as the reference surface of the optical element X as described above, it is convenient in the description of the configuration of the optical element X. Further, in the product in which the present technology is embodied, a large number of micro-mirrors 20 are formed on the substrate 10, but in the drawing, the size of the micro-mirrors 20 is exaggerated and the number of micro-mirrors 20 is shown. It is omitted to the extent that it can be illustrated.

  By the way, in forming the micromirror array structure (micromirror 20), optical holes formed perpendicular to the substrate 10 can be used as shown in FIG. For example, a plurality of rectangular through holes H (here, square through holes H) penetrating perpendicularly to the main surface of the substrate 10 may be formed in the thickness direction of the substrate 10. That is, the micromirror 20 is formed on the inner wall surfaces 21 and 22 of the four inner wall surfaces 21 to 24 that define the through hole H, and is a two-sided corner reflector that is bent at a right angle (a reflection surface on which specular reflection of light occurs). )It has become. On the other hand, the inner wall surfaces 23 and 24 facing each of the inner wall surfaces 21 and 22 that have been mirror-finished are finished as non-reflective surfaces from the viewpoint of suppressing stray light due to multiple scattering of light, or these inner wall surfaces 23 and 24 may be formed so as not to be perpendicular to the element surface S so as not to be parallel to the mirror surface.

  Here, the hollow through hole H described above is exemplified as the “optical hole”. However, in the present specification, the “optical hole” is not necessarily limited to this and can transmit light. It only has to be a part. For example, by arranging a transparent rectangular solid in the hollow part of such a through hole H, or by filling a transparent gas or liquid in the hollow part of the through hole H, “optical” The function of the “hole” is exhibited, whereby the refractive index of the hollow portion of the through hole H can be adjusted appropriately.

  Next, an example of the design specification of the micromirror array structure will be described.

  In the micromirror array structure described above, the width in two directions of the through hole H used for the micromirror 20 may be set within a range of, for example, 50 μm or more and 1000 μm or less. In this embodiment, the width is set to about 100 μm. Further, the height of the through hole H (corresponding to the thickness of the substrate 10) may be set within a range of 50 μm or more and 1000 μm or less, for example. In this embodiment, the thickness is set to about 100 μm. The width of the above-described through hole H defines the width of the two mirror surfaces used for the micromirror 20, and the height of the above-described through hole H defines the height of the two mirror surfaces used for the micromirror 20. Therefore, in the present embodiment, these mirror surfaces are squares having substantially the same width and height. Thus, in the present embodiment, the micromirror 20 is laid on the substrate 10 of about 5 cm square, so that tens of thousands to hundreds of thousands of micromirrors 20 are incorporated in the substrate 10. Yes.

  Next, an example of a method for manufacturing a micromirror array structure will be described.

  First, a cylindrical body aligned with a metal mold is created by nano machining. Then, a smooth mirror surface having a surface roughness of 50 nm or less is formed on the side surface of the cylindrical body corresponding to the inner wall surfaces 21 and 22 described above. Next, reversal transfer is performed by the nanoimprint method or the electroforming method using the created mold, thereby forming each micromirror 20 using a plurality of through holes H having a predetermined pitch.

  When the substrate 10 is made of a metal such as aluminum or nickel by using an electroforming method, the inner wall surfaces 21 and 22 naturally become mirror surfaces if the surface roughness of the mold is sufficiently small. Further, when the substrate 10 is made of resin using the nanoimprint method, the inner wall surfaces 21 and 22 may be mirror-coated by a sputtering method.

  According to the micromirror array structure described above, the light entering the through hole H from one side (front side or back side) of the substrate 10 is specularly reflected by one mirror surface (one of the inner wall surfaces 21 and 22). Further, the reflected light is mirror-reflected by the other mirror surface (the other of the inner wall surfaces 21 and 22) and passed to the other side (back surface or front surface) of the substrate 10.

  That is, in the optical element X of the present embodiment, when the light passes through the micromirror region S1 of the element surface S, the light from the mirror surfaces (inner wall surfaces 21 and 22) erected perpendicular to the element surface S. Specular reflection occurs twice. Thereby, the element surface S is a surface on which a real image of the projection object O on one side of the substrate 10 is formed as a mirror image P at a plane symmetrical position on the other side.

  Note that the optical function (optical characteristics by twice reflected light) of such a micromirror array structure has already been described in detail in Patent Document 1 described above. Therefore, detailed description of the function of the micromirror array structure is omitted here.

  Next, the configuration and function of the screen area S2 that can project the planar image P1 (see FIG. 1), which is a characteristic part of the display system 100 of the present embodiment, will be described.

  FIG. 3 is an enlarged view of the element surface at the substrate end of the optical element of FIG.

  As shown in FIG. 1, the display system 100 of this embodiment includes a projector 30 that irradiates image light 30 </ b> A toward the surface (front surface) side of the substrate 10 of the optical element X described above. As the projector 30, a known system such as a CRT projector, a liquid crystal projector, or a DLP projector can be used. Therefore, detailed description of the configuration and functions of the projector 30 is omitted here.

  As shown in FIGS. 2 and 3, the optical element X of the present embodiment includes a screen area S2 that has a light reflection characteristic different from that of the micromirror area S1 and is parallel to the element surface S. This is an area where irregular reflection of the image light 30A from the projector 30 occurs.

  As can be understood from the shaded illustration in FIG. 3, when the element surface S is viewed in plan, the screen region S2 of the optical element X is formed on the substrate 10 other than the above-described rectangular (here, square) through-holes H. More specifically, the screen region S2 is formed in two directions parallel to the width direction of the through hole H so as to surround each of the rectangular (here, square) micromirror regions S1. It extends to.

  Thereby, in the optical element X of the present embodiment, a planar image P1 using the image light 30A from the projector 30 is formed in the dead space between the micromirrors 20 that did not have an optical function in the conventional optical element X ′ (FIG. 1) can be effectively used as the screen area S2 on which projection can be performed. In the present embodiment, since the micromirror region S1 of the optical element X is a minute square region of about 100 μm, even when the planar image P1 is projected onto the screen region S2, the micromirror region S1 is not visible in viewing the planar image P1. It doesn't matter.

  In order to form the above-described screen region S2, embossing or the like is preferably performed on the surface of the substrate 10 using a mold so that the image light 30A is appropriately irregularly reflected.

  As described above, the optical element X of the present embodiment includes the micromirror region S1 and the screen region S2 having different light reflection characteristics. The micromirror region S1 is a region where specular reflection of light occurs by the micromirror 20 (reflecting surface) standing on the element surface S. The screen region S2 is a region where irregular reflection of light occurs due to the surface (reflection surface) of the substrate 10 parallel to the element surface S.

  With the above configuration, in the display system 100 of the present embodiment, when the light 200 emitted from the projection object O arranged in the space on the back side of the optical element X passes through the element surface S, the micromirror region S1 The real image (mirror image P) of the projection object O can be formed in the space on the surface side of the optical element X by the specular reflection of the light 200 by the micromirror 20. At the same time, the planar image P1 related to the real image of the projection object O can be projected onto the screen region S2 on the surface of the substrate 10 by the irregular reflection of the image light 30A from the projector 30 in the screen region S2.

  In this way, the display system 100 of the present embodiment is beneficial in improving the expressiveness of the video. For example, when a three-dimensional human image is created in the space on the substrate 10 constituting the element surface S, when a two-dimensional shadow of the human image is simultaneously displayed on the screen region S2 on the surface of the substrate 10, Compared with the optical element X ′, it is possible to reproduce an image rich in reality. And, by improving the expressiveness of such video, it can be expected that the display system 100 will be used for various purposes such as entertainment stereoscopic video, exhibition at a museum with stereoscopic video, and product advertisement with stereoscopic video.

(Modification)
In the optical element X of the present embodiment, the micro mirror 20 is formed on the inner wall surfaces 21 and 22 of the hollow through hole H as described above.

  In the optical element XX of this modification, instead of such a micromirror 20, as shown in FIG. 4, a transparent rectangular body that is arranged in a matrix and protrudes from the surface of the substrate 110 in the thickness direction of the substrate 110. A micromirror 120 is formed using D. In this case, the micromirror 120 is formed on the side wall surfaces 121 and 122 among the four side wall surfaces 121 to 124 that define the rectangular body D, and is a two-sided corner reflector that is bent at a right angle (reflection that causes specular reflection of light). Surface). On the other hand, the side wall surfaces 123 and 124 facing the respective side wall surfaces 121 and 122 that have been mirror-finished are finished to be non-reflective from the viewpoint of suppressing stray light due to multiple scattering of light, or these side wall surfaces. 123 and 124 may be formed so as not to be perpendicular to the element surface (not shown) so as not to be parallel to the mirror surface.

  Further, in the formation of the screen region (not shown in FIG. 4), the space between the rectangular bodies D is filled with an appropriate filling member (not shown), and the surface of the filling member becomes an irregular reflection surface. Processing should be done.

  The present invention provides an optical element that can effectively use a dead space between micromirrors capable of forming an aerial image, and a display system including the optical element. Therefore, the present invention can be used for various purposes such as entertainment stereoscopic video, exhibition at a museum with stereoscopic video, and product advertisement with stereoscopic video.

10, 110 Substrate 20, 120 Two-sided corner reflector (micro mirror)
30 Projector 30A Image light 100 Display system O Projected object P Mirror image (aerial image)
P1 plane image S element surface S1 micromirror region (first region)
S2 Screen area (second area)
X, XX Optical element

Claims (3)

A substrate including a first region and a second region having different light reflection characteristics, and partitioned by the first region and the second region;
The first region is a region where specular reflection of light is caused by one or more reflecting surfaces erected with respect to the element surface,
Said second region, Ri region der irregular reflection of light by the element plane and parallel reflecting surfaces occur,
When the element surface is viewed in plan, the rectangular first regions are arranged in an island-like manner, and the second region surrounds each of the first regions,
Each reflective surface of the first region is provided on an inner wall surface of a rectangular optical hole formed perpendicular to the substrate,
The reflection surface of the second region is an optical element provided over the entire surface of the substrate other than the hole . The first region includes a first region and a second region having different light reflection characteristics, and the first region is a region where specular reflection of light is caused by one or more reflection surfaces standing on the element surface, and the second region is An optical element that is a region where irregular reflection of light occurs by a reflecting surface parallel to the element surface ;
A projector for irradiating image light toward the surface of the optical element;
When the light emitted from the projection object arranged in the space on the back surface side of the optical element passes through the element surface, the space on the surface side of the optical element is reflected by specular reflection of the light in the first region. Can form a real image of the projection object,
A display system capable of projecting a planar image related to a real image of the projection object onto the second region by irregular reflection of the image light in the second region. The display system according to claim 2 , wherein the second area functions as a screen area for projecting the planar image.

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