JP2006259058A - Three-dimensional picture display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a three-dimensional picture display device capable of reproducing a three-dimensional picture having a stereoscopic effect with simple configuration. <P>SOLUTION: This three-dimensional picture reproducing device has: a display element 2 displaying an element picture on a two-dimensional plane comprising a plurality of horizontal and vertical parallax pictures 1 including information concerning parallax and pictures in the case of reproducing the three-dimensional stereoscopic picture 7; and a lens 3 forming the element picture displayed by the display element 2 as the three-dimensional stereoscopic picture 7 at a predetermined intersection 5 in space. In the three-dimensional picture reproducing device, the lens 3 diffracts and emits the element picture and forms the three-dimensional picture by a diffraction effect in the case of emitting the element picture from the display element 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a three-dimensional image display device that enables three-dimensional display of an image.

  Conventionally, as a means for displaying a three-dimensional image based on information about the three-dimensional image and for allowing the observer to recognize the three-dimensional image, two images including binocular parallax are displayed with the right eye and the left eye. Autostereoscopic parallelism for viewing the left image, stereoscope for viewing images using glasses with liquid crystal shutters and different lenses for the right and left eyes, red for binocular parallax pictures with different colors of red and blue There was an anaglyph method to look through blue glasses. However, special glasses and training were necessary for an observer to view a three-dimensional image using these methods.

  In recent years, with the development of liquid crystal technology, liquid crystal displays capable of three-dimensional display of images without using special glasses have been announced one after another. Most of the liquid crystal displays are image splitter type glasses-less 3D liquid crystal display elements, that is, 3D image display devices having only a so-called parallax barrier type or lenticular lens type horizontal parallax.

  In a parallax barrier type or lenticular lens type 3D display device, the image light path is spatially separated and supplied so that the right eye image can be seen from the right eye position and the left eye image can be seen from the left eye position. Is caused. Accordingly, image light paths are periodically supplied to the right eye position and the left eye position periodically in the space, and if the position is shifted, the solid is broken. In addition, since an image including a parallax in the horizontal direction is supplied in principle, there is a problem that the solid is broken if the right eye position and the left eye position are deviated from the horizontal direction. For this reason, if stereoscopic viewing is to be performed while maintaining a three-dimensional moving image solid for a long time, it is necessary to fix the right eye position and the left eye position at fixed positions in space.

  For horizontal right-eye position and left-eye position deviations, a method is also devised in which the position of the observer's eyes or face is specified by a sensor, and the image optical path is controlled and corrected according to the specified position deviation. However, the apparatus becomes large and inconvenience that a marker must be attached to the observer in order to sense the position of the eyes and the position of the face.

  In recent years, as a method for solving these problems, M.I. G. The integral photography proposed by Lipmann in 1908 was developed, and a three-dimensional display system using a two-dimensional display panel such as a liquid crystal and a pinhole or fly-eye lens array instead of a film has been proposed ( For example, see Patent Document 1).

M.M. G. In integral photography by Lipmann, a film is placed at the focal position of a fly-eye convex lens array, and an image for each fly-eye convex lens is recorded on the surface of the film. When the recorded image is reproduced, a stereoscopic image is reproduced using the same fly-eye convex lens array as that used for photographing the image of each fly-eye convex lens recorded on the film.
JP 2001-275134 A

  In order to display a smooth high-resolution three-dimensional image by integral photography, it is necessary to arrange different parallax images in one pinhole or lens having a small aperture. At this time, the apparent two-dimensional resolution depends on the diameter of the pinhole or lens array lens, but the apparent three-dimensional image information also depends on the density of the image formed in the depth direction. Therefore, the image information of the apparent three-dimensional image is not uniquely determined by the size of the diameter of the lens of the two-dimensional pinhole or lens array. However, when a human views a three-dimensional image, if the lens outline is clear, the resolution decreases due to the awareness of the size of the outline.

  In the conventional integral photography method or light ray reproduction method, a convex lens array or pinhole array formed of glass or resin is used as a means for forming a two-dimensional image including a parallax image in a space. The outline of the image was clear, and the 2D resolution was hindered by this outline. Also, there is an example in which an integral photography system is realized using a lenticular lens array, but this also hinders the two-dimensional resolution due to the vertical stripe contour of the lenticular lens.

  In addition, when a 3D image is displayed using a fly-eye lens array, a lenticular lens array, or a pinhole array, the display data of the 2D display unit set to display with the adjacent lens or pinhole is connected. Crosstalk occurs. For this reason, attempts have been made to reduce crosstalk by using a lens with a short focal length to make it difficult to geometrically display the display data of the adjacent lens geometrically. In order to realize a short focal length with an optical system having a simple structure, it is effective to reduce the radius of curvature of the lens, but it is very difficult to efficiently produce a lens array having a small radius of curvature. Attempts have also been made to optically insulate each lens with a shielding mask, but there is a problem that the three-dimensional reproduction image becomes dark and the contour effect of the shielding mask impedes the three-dimensional reproduction. It was.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a three-dimensional image display device capable of reproducing a three-dimensional image having a stereoscopic effect with a simple configuration.

  In order to solve the above problems, a 3D image display apparatus according to the present invention displays a component image on a 2D plane composed of a plurality of viewpoint images including information on parallax and images when reproducing a 3D image. And a lens for forming each element image displayed on the display unit as a three-dimensional image at a predetermined intersection in the space, the lens emits each element image from the display unit Further, each element image is diffracted and emitted, and a three-dimensional image is formed by a diffraction effect.

  According to the present invention, the apparent resolution of the three-dimensional image display is improved, the image quality is improved, and it is possible to reproduce a three-dimensional image having a stereoscopic effect.

  A first three-dimensional image display apparatus according to the present invention includes a display unit that displays an element image on a two-dimensional plane including a plurality of viewpoint images including information on parallax and images when reproducing a three-dimensional image, and a display unit In a three-dimensional image display device having a lens that forms each element image displayed by a lens at a predetermined intersection in space as a three-dimensional image, the lens is configured to output each element image from the display unit when each element image is emitted. The image is diffracted and emitted, and a three-dimensional image is formed by the diffraction effect. With this configuration, when each element image is emitted from the display unit, the lens forms a three-dimensional image on each element image by the diffraction effect, so that the apparent resolution of the three-dimensional image display is improved with a simple configuration. At the same time, the image quality can be improved.

  A second three-dimensional image display device according to the present invention is the first three-dimensional image display device including a zone plate in which a lens alternately forms a concentric transparent region ring and an opaque region ring. Has been. With this configuration, since the zone plate reproduces each element image, it is possible to make it difficult for the observer of the three-dimensional image to be aware of the lens outline.

  The third three-dimensional image display device of the present invention is the first three-dimensional image display device, wherein the lens includes a binary optical element having a blazed cross-sectional shape. With this configuration, since the binary optical element reproduces each element image, it is possible to make it difficult for an observer of the three-dimensional image to be aware of the lens outline.

  According to a fourth three-dimensional image display device of the present invention, in the third three-dimensional image display device, the binary optical element is a Fresnel lens. With this configuration, since the Fresnel lens reproduces each element image, it is possible to make it difficult for the observer of the three-dimensional image to be aware of the lens outline.

  The fifth three-dimensional image display device of the present invention is configured to include a holographic lens in which the lens is formed of a hologram in the first three-dimensional image display device. With this configuration, since the holographic lens reproduces each element image, it is possible to make it difficult for the observer of the three-dimensional image to be aware of the lens outline.

  The sixth three-dimensional image display device of the present invention is configured by including a kinoform whose lens is a phase hologram in the first three-dimensional image display device. With this configuration, since the kinoform reproduces each element image, it is possible to make it difficult for the observer of the three-dimensional image to be aware of the outline of the lens.

(Embodiment 1)
Hereinafter, the three-dimensional image display apparatus according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram for explaining the configuration of the three-dimensional image display apparatus according to the first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a horizontal / vertical parallax image displayed by the three-dimensional image display device, 2 denotes a display element that displays a horizontal / vertical parallax image 1, and 3 denotes a lens that forms each parallax image of the horizontal / vertical parallax image 1 in space. Reference numeral 4 denotes a lens array in which the lenses 3 are assembled in a planar shape.

  A three-dimensional image display device including a horizontal / vertical parallax image 1, a display element 2, and a lens array 4 composed of a plurality of lenses 3 displays a three-dimensional image by an integral photography method. Note that the horizontal / vertical parallax image 1 here is an element image serving as an element of reproduction, and a three-dimensional image is displayed by reproduction by the three-dimensional image display device. Further, the horizontal / vertical parallax image 1 is different depending on the image information on the color, gloss, texture, shape, etc. of the object when reproduced as a three-dimensional image, and the position of the line of sight of the image. Contains information about the shape.

  The three-dimensional image display device projects a horizontal / vertical parallax image 1 onto an imaging point 5 in space. The horizontal / vertical parallax image 1 projected onto the imaging point 5 by the three-dimensional image display device enters the observer's eye 6 as a three-dimensional image, and becomes a three-dimensional stereoscopic image 7 including a plurality of horizontal / vertical parallaxes. Specifically, each parallax image of the horizontal / vertical parallax image 1 displayed on the display element 2 of the three-dimensional image display device is imaged at an imaging point 5 in the space using the diffraction effect by the lens 3.

  The horizontal / vertical parallax image 1 is an image from which the three-dimensional stereoscopic image 7 is formed. The horizontal / vertical parallax image 1 is recorded in advance by placing a film at the focal position of the lens 3 and recording an image of each lens 3 on the surface of the film. The display element 2 is an element that displays the horizontal / vertical parallax image 1 and includes, for example, a liquid crystal panel.

  Here, the integral photography method will be described in detail. FIG. 2 is a diagram for explaining the principle of the integral photography system. Integral photography G. This is a 3D image reproduction method proposed by Lipmann in 1908.

  In integral photography, a film is placed at the focal position of a fly-eye convex lens array, and an image of each fly-eye convex lens is recorded on the surface of the film. When the recorded image is reproduced, a stereoscopic image is reproduced using the same fly-eye convex lens array as that used for photographing the image of each fly-eye convex lens recorded on the film.

  As shown in FIG. 2, when the reproduction element image 8 is displayed on the display element 9 for displaying the reproduction element image 8 so as to correspond to each convex lens 11 of the convex lens array 10 having a fly-eye shape, the reproduction element image 8 is displayed. Through each convex lens 11, an image is formed at an image forming point 12 corresponding to the pixel position on the original image surface. For this reason, when a light ray 13 is actually generated from the imaging point 12 and the light ray 13 enters the observer's eye 14, a three-dimensional stereoscopic image 15 having a stereoscopic effect is reproduced to the observer.

  Since the observer actually has the imaging point 12 in the space, even if the angle at which the three-dimensional image display device is installed or the angle at which the observer views the three-dimensional stereoscopic image 15 is changed, or the position of the eye is moved. The three-dimensional stereoscopic image 15 having a three-dimensional feeling can be stably viewed. In the first embodiment, a zone plate which is a kind of lens using a diffraction effect is used instead of the fly-shaped convex lens array 10.

  Here, the zone plate used in the three-dimensional image display apparatus of Embodiment 1 will be described. FIG. 3 is a diagram for explaining the concept of the zone plate included in the three-dimensional image display apparatus according to the first embodiment.

  In FIG. 3, 16 is the overall shape of the zone plate. The zone plate 16 is an optical element that collects light rays at one point and forms an image by bending the light traveling direction using the light diffraction phenomenon.

  The zone plate 16 is formed by alternately forming concentric transparent region rings and opaque region rings on the substrate, and each ring diameter is proportional to, for example, the square root of a natural number counted from the center. Many are drawn. For example, the radius r of the ring constituting the zone plate 16 can be calculated by r = √nλf where f is a focal length, λ is a wavelength of incident light, and n is a natural number.

  As the zone plate 16, a ring shape obtained by a predetermined calculation in advance is printed on a photograph or a photosensitive resin. When parallel incident light 17 is incident in a direction perpendicular to the burned surface of the zone plate 16, the incident light 17 is diffracted by the diffracting portion 18 of the zone plate and emerges as emitted light 19 whose traveling direction is bent. Go. The emitted light 19 forms an image at a focal point 21 on the optical axis 20 passing through the center of the ring pattern of the zone plate 16, so that the zone plate 16 functions as a lens.

  Further, the details of the zone plate 16 will be described with reference to FIG. 1. In the present invention, the lens 3 using the zone plate 16 has a diameter of 1 mm, for example, and is a liquid crystal panel that is a display element 2 for displaying a horizontal / vertical parallax image 1 For example, a resolution of 200 dpi is used.

  In this case, the reproduction element image 8 of the lens using one zone plate 16 is composed of an image of 10 × 10 pixels, and the number of parallaxes in the horizontal and vertical directions can reproduce a smooth three-dimensional stereoscopic image with 10 fields of view. It becomes possible. In order to obtain a natural three-dimensional stereoscopic image, for example, it is effective to reproduce the reproduction element image 8 having a resolution of 200 to 700 dpi by the lens array 4 using the zone plate 16 having a diameter of 1 mm or less. The means for displaying the horizontal / vertical parallax image 1 (display element 2) is not limited to a liquid crystal panel, and a plasma display panel, an organic EL panel, or the like may be used.

  As described above, according to the first embodiment, since the reproduction element image 8 is reproduced by the lens array 4 using the zone plate 16, it becomes difficult for the observer to be aware of the outline of the lens, and a lens having a short focal length is used. Thus, crosstalk can be easily reduced. Therefore, the 3D image display apparatus can improve the apparent resolution of 3D image display and improve the image quality with a simple configuration. Thereby, the three-dimensional image display apparatus can perform image reproduction with a stereoscopic effect.

(Embodiment 2)
Next, a projection type three-dimensional display device according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a diagram showing a configuration of the three-dimensional image display apparatus according to the second embodiment of the present invention. In FIG. 4, 22 is a light source, 23 is light emitted from the light source 22, 24 is a condenser lens, 25 is a projection device, 26 is a projection lens, 27 is a prism, 28 is an imaging screen, and 29 is a diffraction effect. The binary optical element 30 is a three-dimensional stereoscopic image.

  The light source 22 is a device that generates the light 23, and includes, for example, a white LED (Light Emitting Diode). The condenser lens 24 condenses the light 23 emitted from the light source 22.

  The projection device 25 is a projection means for controlling the shape of the projection image, and enters the light condensed by the condenser lens 24. The projection device 25 modulates the incident light as a projection image (a modulation pattern formed on the reflection surface of the projection device 25), and adds image information. The projection device 25 includes, for example, a transmissive liquid crystal.

  The projection lens 26 receives the light modulated by the projection device 25 and sends it out to the prism 27. The prism 27 changes the projection angle of the light from the projection lens 26 and projects it onto the imaging screen 28.

  The imaging screen 28 images the light projected from the prism 27 as a projection image. The imaging screen 28 includes, for example, a hologram diffusion plate. The binary optical element 29 is a means for controlling and imaging light in space using the diffraction effect of light, and forms a projection image formed on the imaging screen 28 in space as a three-dimensional stereoscopic image 30.

  Next, a procedure for forming a projection image by the three-dimensional display device will be described. In FIG. 4, the light 23 emitted from the light source 22 is collected by the condenser lens 24 and enters the projection device 25. The projection device 25 modulates the light from the condenser lens 24 into a projection image and adds image information. Thereby, the projection device 25 controls the shape of the projection image.

  The light modulated by the projection device 25 passes through the projection lens 26 and the projection angle is changed by the prism 27. The light whose projection angle has been changed by the prism 27 is projected onto the imaging screen 28 to form a projection image.

  Since the projection image formed on the imaging screen 28 is an integral photography type ray-trace image, it passes through the binary optical element 29 using the diffraction effect as a means for controlling and forming an image in the space. A three-dimensional stereoscopic image 30 can be formed.

  In the second embodiment, a binary optical element is used as means for controlling and forming an element image including image information using the diffraction effect in a space. The binary optical elements 29 are two-dimensionally arranged on a plane parallel to the plane on which the imaging screen 28 forms a projection image, and function as a lens array.

  Here, the binary optical element used in the three-dimensional image display apparatus of Embodiment 2 will be described in detail. FIG. 5 is a diagram for explaining the concept of the binary optical element included in the three-dimensional image display apparatus according to the second embodiment.

  In FIG. 5, reference numeral 31 denotes the overall shape of the binary optical element. The binary optical element 31 is created by approximating a diffractive optical element having a blazed cross-sectional shape such as a Fresnel lens in a stepped shape like the element cross-sectional portion 32.

  The binary optical element 31 having the element cross section 32 forms a diffraction grating having a fine shape on the surface of a substrate on a transparent substrate. The binary optical element 31 collects light at one point and forms an image by bending the light traveling direction using the diffraction phenomenon of light.

  When parallel incident light 33 is incident in a direction perpendicular to the back surface of the element cross section 32 with respect to the surface direction of the binary optical element 31, the incident light 33 is diffracted by the diffraction unit 34 of the binary optical element 31 and travels. The light is emitted from the binary optical element 31 as the outgoing light 35 whose direction is bent.

  The outgoing light 35 emitted from the binary optical element 31 forms an image at a focal point 37 on the optical axis 36 that passes through the center of the pattern of the binary optical element 31. Thereby, the binary optical element 31 functions as a lens.

  As the binary optical element 31 of the present invention, for example, a binary optical element 31 having a diameter of 1.5 mm is used. In addition, the resolution of a projected image projected and imaged on the imaging screen 28 is, for example, 200 dpi. In this case, the reproduction element image of one binary optical element 31 is composed of an image of 10 × 10 pixels, and it is possible to reproduce a smooth three-dimensional stereoscopic image having 10 fields of view in the horizontal and vertical directions. In order to obtain a natural three-dimensional stereoscopic image, for example, it is effective to reproduce a reproduction element image having a resolution of 200 to 700 dpi with the binary optical element 31 having a diameter of 1.5 mm or less.

  In the second embodiment, the three-dimensional image display device includes a white LED as the light source 22. However, the light source 22 is not limited to the white LED, and each color LED, an organic EL (Electro Luminescence), a halogen lamp, and the like. May be used.

  In the second embodiment, the three-dimensional image display device is configured to include the hologram diffusion plate as the imaging screen 28. However, the imaging screen 28 is not limited to the hologram diffusion plate, and may be an embossed diffusion plate or a hologram screen. Etc. may be used.

  As described above, according to the second embodiment, since the binary optical element 29 using the binary optical element 31 forms a three-dimensional image, it becomes difficult for the observer to be aware of the lens outline, and a lens with a short focal length is used. It is possible to easily reduce crosstalk by using. Therefore, the 3D image display apparatus can improve the apparent resolution of 3D image display and improve the image quality with a simple configuration. Thereby, the three-dimensional image display apparatus can perform image reproduction with a stereoscopic effect.

(Embodiment 3)
Next, a three-dimensional image display apparatus according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a diagram for explaining the configuration of the three-dimensional image display apparatus according to the third embodiment of the present invention. In FIG. 6, reference numeral 1 denotes a horizontal / vertical parallax image displayed by the three-dimensional image display device, 2 denotes a display element that displays the horizontal / vertical parallax image 1, and 43 denotes a lens that forms each parallax image of the horizontal / vertical parallax image 1 in space. , 44 is a lens array in which the lenses 43 are assembled in a planar shape.

  A three-dimensional image display device including a horizontal / vertical parallax image 1, a display element 2, and a lens array 44 including a plurality of lenses 43 displays a three-dimensional image by an integral photography method.

  The three-dimensional image display device projects a horizontal / vertical parallax image 1 onto an imaging point 5 in space. The horizontal / vertical parallax image 1 projected onto the imaging point 5 by the three-dimensional image display device enters the observer's eye 6 as a three-dimensional image, and becomes a three-dimensional stereoscopic image 7 including a plurality of horizontal / vertical parallaxes. Specifically, each parallax image of the horizontal / vertical parallax image 1 displayed on the display element 2 of the three-dimensional image display device is imaged at the imaging point 5 in the space using the diffraction effect by the lens 43.

  The horizontal / vertical parallax image 1 is an image from which the three-dimensional stereoscopic image 7 is formed. The horizontal / vertical parallax image 1 is recorded in advance by placing a film at the focal position of the lens 43 and recording an image of each lens 43 using the diffraction effect on the surface of the film.

  The display element 2 is an element that displays the horizontal / vertical parallax image 1 and includes, for example, a liquid crystal panel. In the third embodiment, the lens array 44 is constituted by a holographic lens, for example.

  Here, the holographic lens used in the three-dimensional image display device of Embodiment 3 will be described. FIG. 7 is a diagram for explaining the concept of the holographic lens included in the three-dimensional image display device according to the third embodiment.

  In FIG. 7, reference numeral 45 denotes the overall shape of the holographic lens. The holographic lens 45 is a diffractive optical element in which a hologram is formed on photosensitive gelatin such as photopolymer or silver halide gelatin.

  The holographic lens 45 is configured on a substrate 46 such as a photopolymer or silver halide gelatin. When the spherical light wave 48 is generated from the focal position of the substrate 46 by the point light source 47 and the parallel light 49 is incident on the substrate 46 from the direction opposite to the incident light direction assumed for image reproduction, the substrate 46 is exposed. A diffraction grating is formed in the inside by a change in refractive index. With this diffraction grating, the light traveling direction can be bent using the light diffraction phenomenon, and the light can be collected at one point to form an image.

  When predetermined parallel incident light 50 is incident on the holographic lens 45, the incident light 50 is diffracted by the diffraction grating of the holographic lens 45 and is emitted from the holographic lens 45 as outgoing light 51 whose traveling direction is bent. To do.

  The outgoing light 51 from the holographic lens 45 forms an image at a focal point 53 on the optical axis 52 that passes through the center of the holographic lens 45. As a result, the holographic lens 45 functions as a lens.

  Further, details of the holographic lens 45 will be described with reference to FIG. As the holographic lens 45 of the present invention, for example, a holographic lens 45 having a diameter of 1 mm is used. In addition, a liquid crystal panel that is a display element 2 that displays the horizontal / vertical parallax image 1 has a resolution of, for example, 200 dpi. In this case, the horizontal / vertical parallax image of one holographic lens 45 is composed of an image of 10 × 10 pixels, and the number of parallaxes in the horizontal / vertical direction can reproduce a smooth three-dimensional stereoscopic image 7 with 10 fields of view. Become. In order to obtain a natural three-dimensional stereoscopic image 7, it is effective to reproduce, for example, a horizontal / vertical parallax image 1 having a resolution of 200 to 700 dpi with a holographic lens 45 having a diameter of 1 mm or less.

  In the third embodiment, the three-dimensional image display device includes the holographic lens 45. However, the configuration is not limited to the holographic lens 45, and the three-dimensional image display device may include a kinoform.

  As described above, according to the third embodiment, since the horizontal / vertical parallax image 1 is reproduced by the lens array 44 using the holographic lens 45, it becomes difficult for the observer to be aware of the outline of the lens, and a lens with a short focal length is used. It is possible to easily reduce crosstalk by using. Therefore, the 3D image display apparatus can improve the apparent resolution of 3D image display and improve the image quality with a simple configuration. Thereby, the three-dimensional image display apparatus can perform image reproduction with a stereoscopic effect.

  As described above, the three-dimensional image display device according to the present invention is suitable for three-dimensional display of images.

The figure for demonstrating the structure of the three-dimensional image display apparatus of Embodiment 1 concerning this invention. Diagram for explaining the principle of integral photography The figure for demonstrating the concept of the zone plate with which the three-dimensional image display apparatus of Embodiment 1 is provided. The figure which shows the structure of the three-dimensional image display apparatus of Embodiment 2 concerning this invention. The figure for demonstrating the concept of the binary optical element with which the three-dimensional image display apparatus of Embodiment 2 is provided. The figure for demonstrating the structure of the three-dimensional image display apparatus of Embodiment 3 concerning this invention. The figure for demonstrating the concept of the holographic lens with which the three-dimensional image display apparatus of Embodiment 3 is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Horizontal vertical parallax image 2 Display element 3,43 Lens 4,44 Lens array 5 Imaging point 6,14 Eye 7,15 Three-dimensional solid image 8 Reproduction element image 9 Display element 10 Convex lens array 11 Convex lens 12 Imaging point 13 Light beam 16 Zone plate 17, 33, 50 Incident light 18, 34 Diffraction unit 19, 35, 51 Emission light 20, 36, 52 Optical axis 21, 37, 53 Focus 22 Light source 23 Light 24 Condenser lens 25 Projection device 26 Projection lens 27 Prism 28 Imaging screen 29, 31 Binary optical element 32 Element cross section 46 Substrate 47 Point light source 48 Spherical wave 49 Parallel light

Claims (6)

A display unit that displays an element image on a two-dimensional plane including a plurality of viewpoint images including parallax when reproducing a three-dimensional image and information about the image, and each element image displayed by the display unit is displayed in a predetermined space. In a three-dimensional image reproducing apparatus having a lens that forms an image as a three-dimensional image at an intersection,
The lens, when emitting each element image from the display unit, diffracts and emits each element image to form a three-dimensional image by a diffraction effect. The three-dimensional image display device according to claim 1, wherein the lens includes a zone plate that alternately forms concentric transparent region rings and opaque region rings. The three-dimensional image display device according to claim 1, wherein the lens includes a binary optical element having a blazed cross-sectional shape. The three-dimensional image display device according to claim 3, wherein the binary optical element is a Fresnel lens. The three-dimensional image display device according to claim 1, wherein the lens includes a holographic lens formed of a hologram. The three-dimensional image display device according to claim 1, wherein the lens includes a kinoform that is a phase hologram.

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