JP2018180344A - Imaging optical system and video display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging optical system in which a real mirror video is properly imaged and a degree of freedom in apparent design is enhanced.SOLUTION: An imaging optical system 1 includes an imaging optical member 2 which has an element flat surface 2S for partitioning one space from the other space and allows the light emitted from a projected object to penetrate for imaging an unmagnified video of the projected object, and a first optical member 3a and a second optical member 3b provided on both sides of the element flat surface 2S respectively. Incident light to the first optical member 3a and an outgoing light from the second optical member 3b are arranged for parity symmetry relationship except for advancing direction of beam. With this configuration, since a projected object (point light source o) focuses on a position p which is opposite to the element flat surface 2S, a real mirror video P can be imaged on the position. A physical interface that is viewed by an observer is a light outgoing surface of the globular second optical member 3b, and which can employ an arbitrary shape, for enhanced freedom degree in apparent design.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an imaging optical system that images a real mirror image of a projection object disposed in one space in the other space, and an image display apparatus using the same.

  An optical element is proposed which arranges a projection object on one surface side of a flat body that divides a certain space, and forms a mirror image of the projection object at a position that is plane symmetric in the space on the other surface side. . As this type of optical element, there is known an optical element having a structure in which a plurality of two-surface corner reflectors each consisting of two minute mirror surfaces (reflecting surfaces) orthogonal to each other are collected in plan (for example, Patent Document 1).

  The patent document 1 discloses an optical element having a dihedral corner reflector array in which a plurality of dihedral corner reflectors are arranged in a grid on one plane. In this optical element, each mirror surface which forms a biplanar corner reflector is disposed perpendicularly to the element plane of the optical element. Therefore, the light emitted from the projection object disposed on one side of the element plane is reflected twice by the two-surface corner reflector when passing through the optical element and is bent, and the other surface without the projection object Image as a real image in the space on the side. As a result, the real image is imaged such that the object to be projected exists at a symmetrical position with respect to the element plane of the optical element.

JP, 2011-191404, A

  However, in an imaging optical system using an optical element as described above, a real mirror image is formed at a plane symmetrical position of a projection object through a flat plane of symmetry which physically exists. Therefore, when this real mirror image is observed as an aerial image, the physical boundary surface viewed by the observer is a flat surface, and the degree of freedom in the appearance design of the apparatus using the imaging optical system is limited. However, when the physical boundary surface is a non-flat surface such as a curved surface or a spherical surface, for example, aberration occurs due to the influence of refraction, and it becomes difficult to appropriately form a real mirror image.

  The present invention solves the above-mentioned problems, and a physical boundary surface in which a real mirror image is appropriately imaged and viewed from an observer can be a non-flat surface, and the degree of freedom in appearance design It is an object of the present invention to provide an imaging optical system that can make the image height high and an image display apparatus using the same.

  In order to solve the above problems, the present invention is an imaging optical system which forms an image of a real mirror image of a projection object disposed in one space in the other space, and the one space and the other space An imaging optical member having an element plane for partitioning light and transmitting light emitted from the object to form an equal-magnification image of the object, and first optical elements respectively provided on both sides of the element plane A member and a second optical member, and the incident light to the first optical member and the outgoing light from the second optical member have a parity symmetry relationship except for the traveling direction of the light beam. Do.

  In the image forming optical system, it is preferable that the first optical member and the second optical member are physically and symmetrically arranged with respect to the element plane.

  In the above-mentioned image forming optical system, it is preferable that a physical boundary surface visually recognized by an observer among the second optical members is a non-flat surface.

  In the above imaging optical system, the imaging optical member is formed of a combination of one or more optical elements for forming a real mirror image of an object to be projected by any one or a combination of refractive, reflective or diffractive optical systems. Preferably.

  In the image forming optical system, the image forming optical member is preferably a two-surface corner reflector array in which a plurality of two-surface corner reflectors composed of two reflecting surfaces disposed substantially perpendicular to each other are arranged.

  In the image forming optical system, the image forming optical member has two or more slit mirror arrays formed by arranging in parallel a plurality of slit mirrors arranged perpendicularly to the element surface, and the array of the slit mirrors is orthogonal to each other It may be a laminated slit mirror array configured to face each other.

  In the imaging optical system, the imaging optical member may include a beam splitter that transmits and reflects incident light, and a retroreflector that retroreflects light reflected by the beam splitter.

  In the imaging optical system, the imaging optical member may be an afocal lens array in which a plurality of afocal lenses having an optical axis perpendicular to the element plane are arranged.

  The imaging optical system is preferably used for an image display device.

  According to the present invention, the object to be projected is condensed at a position opposite to the element plane, so that a real mirror image can be formed at this position. In addition, the physical boundary surface visually recognized by the observer is the light exit surface of the spherical second optical member, and any shape can be adopted for this, so the degree of freedom in appearance design can be increased. it can.

FIG. 1 is a schematic perspective view showing a configuration example of an image display apparatus using an image forming optical system according to a first embodiment of the present invention. The side sectional view of the above-mentioned picture display device. FIG. 5 is a schematic perspective view showing a configuration example of an imaging optical member used in the imaging optical system. (A) and (b) are figures which show the imaging mode by an imaging optical member typically. (A) and (b) are perspective views which show the structural example of a 2 surface corner reflector array as said imaging optical member. FIG. 7 is a perspective view showing a configuration example of a laminated slit mirror array used as the imaging optical member. (A) and (b) are side views for demonstrating the imaging principle of the said imaging optical system. The side view which shows notionally the structural example of the imaging optical system which concerns on the modification of the said embodiment. The side view which shows notionally the structural example of the imaging optical system which concerns on the modification of the said embodiment. (A) thru | or (c) is a side view which shows notionally the structural example and display principle of the imaging optical system which concern on another modification of the said embodiment. (A) is a side view which shows notionally the structural example of the imaging optical system which concerns on the 3rd Embodiment of this invention, (b) is an afocal lens array as an imaging optical member used for the said imaging optical system The side view showing roughly the example of composition of a.

  An imaging optical system and an image display apparatus using the same according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 7. As shown in FIGS. 1 and 2, the image display apparatus 10 according to the present embodiment includes a box 12 having an opening 11 on the upper surface, an imaging optical member 2 attached to the opening 11, and a box 12. And a video display unit 13 provided in the internal space. The imaging optical member 2 has an element plane 2S that divides one space (the inner space of the box 12) and the other space (the outer space of the box 12), and transmits light emitted from the object to be projected To form an equal-magnification image of the object to be projected. The image display apparatus 10 further includes a first optical member 3 a and a second optical member 3 b provided on both sides of the element plane 2 S of the imaging optical member 2. The imaging optical system 1 applied to the image display apparatus 10 of the present embodiment is mainly configured by the imaging optical member 2, the first optical member 3a and the second optical member 3b.

  The imaging optical member 2 is a flat plate having translucency, and when transmitting light emitted from an object to be projected in the internal space of the box 12, any one of a refraction, reflection, and diffraction optical system or By combining them, an equal-magnification real image of the object to be projected is formed in the other space.

  In the present embodiment, two transparent spheres are provided as the first optical member 3a and the second optical member 3b in plane symmetry with respect to the one-element plane 2S. The first optical member 3a and the second optical member 3b in the illustrated example are formed of materials having the same refractive index, and all have the same shape and the same size. In addition, one first optical member 3a is provided at a position facing the image display unit 13 in the box 12, and the other second optical member 3b is physically present with respect to the first optical member 3a and the element plane 2S. Are arranged in plane symmetry.

  The image display unit 13 uses, for example, a liquid crystal display device, and is held in a predetermined inclined posture in the box 12. Further, as shown in the figure, on the image display unit 13, a predetermined image (here, the letter "A") is displayed in an inverted posture upside down (corresponding to the point light source o in FIG. 2). The box 12 is not limited to the illustrated configuration example as long as the box 12 can maintain the positional relationship between the imaging optical member 2, the image display unit 13, the first optical member 3a, and the second optical member 3b. Any shape may be employed.

  In the configuration example shown in FIGS. 1 and 2, the light emitted from the image display unit 13 is refracted and transmitted by the first optical member 3a, and then bent and reflected by the imaging optical member 2, and further the second optical member 3b. Through the lens to form a real mirror image. When the observer looks into the second optical member 3b with the viewpoint set at the obliquely upper position of the second optical member 3b (corresponding to the position p in FIG. 2), the viewer sees a real mirror image of the letter "A" It can be viewed as

  The imaging optical member 2 used in the imaging optical system 1 of the present embodiment, as shown in FIG. 3, comprises reflecting surfaces (vertical surfaces 22 and 23) perpendicular to the base 21 and substantially orthogonal to each other. A two-surface corner reflector array 20S in which a plurality of two-surface corner reflectors 20 are arranged is preferably used. The two-surface corner reflector array 20S is configured by arranging a plurality of two-surface corner reflectors 20 in a grid shape on one plane of the base 21.

  When the projection object O is disposed on one surface side of the imaging optical member 2 using the dihedral corner reflector array 20S, the imaging optical member 2 is a real image (real mirror image P) of the projection object O. The image is formed in the space on the other surface side of the element plane 2S. That is, the imaging optical member 2 forms an image of the real mirror image P of the projection object O at a plane symmetrical position where the element plane 2S is a plane of symmetry. The element plane 2S is a virtual plane orthogonal to the two vertical planes 22 and 23 constituting the two-face corner reflector 20. Note that the two-surface corner reflector 20 is finer than the overall size of the imaging optical member 2 in the cm or m order, and in the μm order, and in FIG. It has shown notionally with V shape.

  The imaging mode by the two-surface corner reflector array 20S will be described with reference to FIGS. 4 (a) and 4 (b). In FIG. 4A, light emitted from the point light source o as an object to be projected travels three-dimensionally from the back side to the front side of the paper surface. The light (solid arrow) emitted from the point light source o passes through the imaging optical member 2 (not shown in FIG. 4A), and one mirror surface (vertical surface 22) that constitutes the two-faced corner reflector 20 , And is reflected by the other mirror surface (vertical surface 23), and then passes through the element plane 2S (see FIG. 4B). The light emitted from the imaging optical member 2 in this manner (one-dot and dash line arrow) passes through the element plane 2S while expanding the plane symmetrical position p of the point light source o. That is, the transmitted light of the imaging optical member 2 is focused at a plane symmetrical position p of the point light source o with respect to the element plane 2S, and forms an image as a real mirror image P (see FIG. 3).

  For example, as shown in FIG. 5A, as the imaging optical member 2 using the dihedral corner reflector array 20S, a plurality of transparent quadrangular prism shapes are formed on a substrate 21 formed of a transparent material and forming a plane. The protrusions 2A are arranged in a lattice, and two adjacent outer surfaces of the protrusions 2A are mirror surfaces (vertical surfaces 22 and 23). The protruding portion 2A is not limited to the quadrangular prism in the illustrated example, and may have, for example, a truncated pyramid shape or the like. Further, as shown in FIG. 5B, a plurality of square holes 2B are formed in the base 21 in a lattice shape, and the two inner side surfaces adjacent to the holes 2B are used as reflection surfaces (vertical surfaces 22 and 23). It may be.

  Further, as shown in FIG. 6, the imaging optical member 2 includes two or more slit mirror arrays 24S, 25S formed by arranging in parallel a plurality of slit mirrors 24, 25 arranged perpendicularly to the element plane 2S, It may be a laminated slit mirror array 26 in which the slit mirrors 24 and 25 are arranged to face each other so that the alignments thereof are orthogonal to each other.

  When the imaging optical system 1 is only the imaging optical member 2, the light (solid arrow) emitted from the point light source o is the same as the case described in FIG. After being reflected by the two-surface corner reflector 20, the light transmitted through the element plane 2S and emitted from the imaging optical member 2 has a plane symmetrical position p of the point light source o with respect to the element plane 2S. Pass while spreading. Then, a real mirror image P (see FIG. 3) is formed by the light focused at the plane symmetrical position p with respect to the element plane 2S of the point light source o.

  Here, as shown in FIG. 7A, when only the first optical member 3a is disposed in the traveling direction of the ray of the point light source o, the light emitted from the point light source o passes through the first optical member 3a. Refraction when. Since the outer surface shape of the first optical member 3 a in the illustrated example is convex, the light emitted from the first optical member 3 a is refractively refracted and enters the imaging optical member 2 and is reflected by the imaging optical member 2. Because they are dispersed when being focused, they do not converge at the plane-symmetrical position p '. Therefore, in this case, a real mirror image is not formed.

  On the other hand, as shown in FIG. 7B, when the second optical member 3b is provided at the plane symmetrical position of the first optical member 3a sandwiching the element plane 2S of the imaging optical member 2, the light is emitted from the second optical member 3b. The light being collected is refractively condensed. The first optical member 3a and the second optical member 3b are formed of materials having the same refractive index, and since both have the same shape and the same size, the light incident on the first optical member 3a and the second optical member 3b The outgoing light has a parity symmetry relationship except for the traveling direction of the light beam. Therefore, the light emitted from the second optical member 3b is focused at the plane symmetrical position p. As a result, a real mirror image P (see FIG. 3) is formed at the plane symmetrical position p of the point light source o with respect to the element plane 2S. Note that "parity symmetry" means so-called "mirror symmetry", but does not necessarily require a mirror surface to be a symmetry plane, so it is referred to as parity symmetry here by explicitly distinguishing it from mirror symmetry. .

  According to the imaging optical system 1 of the present embodiment, the physical boundary surface visually recognized by the observer is the light emission surface of the spherical second optical member 3b, and any shape including the non-flat surface is used. It can be done. Therefore, the conventional physical boundary surface is not limited to a flat surface, and the degree of freedom in appearance design can be increased, and a real mirror image can be appropriately imaged.

  The conditions under which the real mirror image is formed include light emitted from the object to be projected and incident on the first optical member 3a, and light transmitted through the imaging optical member 2 and emitted from the second optical member 3b. It is a relation of parity symmetry except for the traveling direction of the ray. Although the example of a structure of a spherical body was mentioned as the 1st optical member 3a and the 2nd optical member 3b in the above-mentioned embodiment, as shown in Drawing 7 (a) (b), the 1st optical member 3a and the 2nd The optical member 3b may have, for example, an elliptical shape as long as the above relationship is satisfied, and is not limited to the spherical body as in the above embodiment. Further, the outer surfaces of the first optical member 3a and the second optical member 3b are not limited to the convex shape, but may be a concave shape.

  As in the modification shown in FIG. 8, the outer surfaces of the first optical member 3 a and the second optical member 3 b may have, for example, a corrugated shape. Also in this modification, even if the light emitted from the point light source o (object to be projected) is further refracted after passing through the one first optical member 3a, after being reflected by the imaging optical member 2, the other Since the light is refracted again by the two optical members 3b, it is possible to focus at the plane symmetrical position p and to form a real mirror image P (see FIG. 3). Further, the first optical member 3a and the second optical member 3b are not limited to the configuration example one on each side of the element plane 2S of the imaging optical member 2, and may be two or more. Furthermore, if the incident light to the first optical member 3a and the outgoing light from the second optical member 3b have a parity symmetry relationship except for the traveling direction of the light beam, the first optical member 3a and the second optical member 3b However, even if they have different shapes, they may be different in number, and they do not necessarily have to be physically arranged in plane symmetry with respect to the element plane 2S.

  In addition, although a part or all of the first optical member 3a (or the second optical member 3b) is not physically symmetrical with respect to the element plane 2S of the imaging optical member 2 as a physical arrangement, it is a plane in consideration of a virtual image. It may be arranged symmetrically. Specifically, as in the modified example shown in FIG. 9, when light from a projection target (here, point light source o) is reflected by the mirror 31 and is incident on the first optical member 3a, the point light source o The virtual image position o ′ of the point light source o due to the mirror 31 is in plane symmetry with the position p, although it is not plane symmetrical with the position p where the light is focused.

  As described above, according to the imaging optical system of the embodiment and the modification, the second optical member 3b is not provided at the plane symmetrical position of the first optical member 3a sandwiching the element plane 2S of the imaging optical member 2. In this case, the real mirror image is not formed, and the real mirror image is formed only when the second optical member 3 b is provided. When the second optical member 3b is provided to correspond to the first optical member 3a, a real mirror image is formed.

  Next, a configuration example and display principle of an image forming optical system according to a second embodiment of the present invention will be described with reference to FIG. The imaging optical system 1 according to the present embodiment includes, as the imaging optical member 2, a beam splitter 27 for transmitting and reflecting incident light, and a retroreflector 28 for retroreflecting light reflected by the beam splitter 27. Are used. The other configuration is the same as the above embodiment.

  In the present embodiment, the light emitted from the point light source o is split by the beam splitter 27 into reflected light and transmitted light. The reflected light is retroreflected by the retroreflector 28, and the light transmitted through the beam splitter 27 forms an image at a point P with a point light source o with respect to the beam splitter 27 (element plane 2S in this embodiment). Also in the present embodiment, when only the first optical member 3a is disposed, focusing is not performed at the plane-symmetrical position p ', and a real mirror image is not formed (not shown). On the other hand, when the second optical member 3b is provided at the plane-symmetrical position of the first optical member 3a sandwiching the beam splitter 27 (element plane 2S), it converges at the plane-symmetrical position p, so the real mirror image P (see FIG. 3) Is imaged.

  Next, a configuration example of an imaging optical system according to a third embodiment of the present invention will be described with reference to FIGS. 11 (a) and 11 (b). In the imaging optical system 1 of the present embodiment, an afocal lens array 4S in which a plurality of afocal lenses 4 having an optical axis perpendicular to a predetermined element plane 2S are arranged is used as the imaging optical member 2. The afocal lens 4 is composed of, for example, two lenses 4a and 4b which have an optical axis g perpendicular to the element plane 2S and which are disposed at respective focal distances. As a specific configuration example of the afocal lens 4, a convex lens, an optical fiber lens or the like is adopted. The light incident on the lens 4a from one side of the element plane 2S is respectively emitted from the lens 4b on the other side forming a pair, and is condensed at a position p that is plane symmetrical with the point light source o with respect to the element plane 2S. . Therefore, the real mirror image P (see FIG. 3) can be formed at the point light source o and the plane symmetrical position p as in the above embodiment and modification.

  The present invention is not limited to the above embodiment and various modifications, and various modifications are possible. In the above-described embodiment and modification, the configuration example of the imaging optical member 2, the image display unit 13, the first optical member 3a, and the second optical member 3b, which are the main components of the present invention, has been described. The imaging optical system may be mounted on a casing (not shown) such that only the light exit surface of the second optical member 3b is exposed on the outer surface of the apparatus. Moreover, this casing and the box 12 (refer FIG. 1) shown by the said embodiment may be comprised so that the 1st optical member 3a and the 2nd optical member 3b can be replaced | exchanged suitably.

DESCRIPTION OF SYMBOLS 1 imaging optical system 10 image display apparatus 2 imaging optical member 2S element plane 20 2 plane corner reflector 20S 2 plane corner reflector array 22 and 23 perpendicular surface (reflection surface)
24, 25 Slit mirror 24S, 25S Slit mirror array 26 Multilayer slit mirror array 27 Beam splitter 28 Retro reflector 4 Afocal lens 4S Afocal lens array O Projected object P Real mirror image

Claims (9)

An imaging optical system for imaging a real mirror image of a projection object disposed in one space in the other space, comprising:
An imaging optical member having an element plane for dividing the one space from the other space, transmitting light emitted from the object to form an equal-magnification image of the object, and A first optical member and a second optical member respectively provided on both sides;
An imaging optical system, wherein incident light to the first optical member and outgoing light from the second optical member have a parity symmetry relationship except for the traveling direction of a light beam.   The image forming optical system according to claim 1, wherein the first optical member and the second optical member are arranged in plane symmetry physically with respect to the element plane.   The imaging optical system according to claim 1, wherein a physical boundary surface visually recognized by an observer among the second optical members is a non-flat surface.   The imaging optical member is composed of a combination of one or more optical elements for imaging a real mirror image of an object to be projected by any one or combination of refractive, reflective or diffractive optical systems. The imaging optical system according to any one of claims 1 to 3.   The imaging optical system according to claim 4, wherein the imaging optical member is a two-surface corner reflector array in which a plurality of two-surface corner reflectors composed of two reflecting surfaces disposed substantially perpendicular to each other are arranged. .   The imaging optical member is configured such that two or more slit mirror arrays formed by arranging in parallel a plurality of slit mirrors arranged perpendicularly to the element surface face each other so that the array of the slit mirrors is orthogonal to each other 5. An imaging optical system according to claim 4, which is a laminated slit mirror array.   5. The imaging optics according to claim 4, wherein the imaging optical member has a beam splitter for transmitting and reflecting incident light, and a retroreflector for retroreflecting the light reflected by the beam splitter. system.   5. The imaging optical system according to claim 4, wherein the imaging optical member is an afocal lens array in which a plurality of afocal lenses having an optical axis perpendicular to the element plane are arranged.   An image display apparatus using the imaging optical system according to any one of claims 1 to 8.

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