JP2012189947A - Display and display unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display a clear image without ghost image due to zeroth-order diffraction light emitted from a diffraction grating.SOLUTION: A display 2 has an optical reflection panel 14 having a prism 40 provided so that diffraction light can be made incident thereon by an optical material which can transmit the diffraction light emitted from a diffraction grating panel 13, and is constituted such that a plurality of images can be displayed to make mutually different images visible from viewpoint positions facing the display 2 and different in the longitudinal direction of the display 2 by transmitting any of minus first-order diffraction light L3c and plus first-order diffraction light L3b as diffraction light through the prism 40 and emitting it from the prism 40. The optical reflection panel 14 is constituted such that transmissivity of zeroth-order diffraction light L3a is less than that of the plus first-order diffraction light L3b (or the minus first-order diffraction light L3c) due to reflection of the zeroth-order diffraction light L3a at the prism 40.

Description

  The present invention includes a display that includes a light diffracting unit that diffracts light from a light source in a predetermined direction, and displays a plurality of images so that different images can be visually recognized for each viewpoint position, and the display. The present invention relates to a display device configured as described above.

  Japanese Patent No. 3283582 discloses a stereoscopic television (stereoscopic image display device) as a display device configured to include this type of display. This stereoscopic television includes a diffraction grating array, a liquid crystal display element provided on the rear surface of the diffraction grating array, and a color filter layer provided on the rear surface of the liquid crystal display element. Specifically, in this stereoscopic television, the color filter layer selects light of a predetermined wavelength from white incident light, and transmits / blocks the selected light through the liquid crystal display element and transmits through the liquid crystal display element. A configuration is employed in which light is diffracted in a desired direction by a diffraction grating array. In this case, the diffraction grating array described above arranges a plurality of cells composed of diffraction gratings in which curved gratings are formed in parallel and arranged on a planar substrate while changing the grating interval (pitch). These cells are divided in the horizontal direction according to the number of parallax images to be displayed. Thereby, different parallax images are observed from the respective viewpoint positions corresponding to the number of divisions of the cells in the diffraction grating array, and are visually recognized as a stereoscopic image.

Japanese Patent No. 3283582 (page 3-6, FIG. 1-12)

  However, the conventional stereoscopic television has the following problems. That is, in a diffraction grating such as a diffraction grating array in a conventional stereoscopic television, as shown in FIG. 47, not only + 1st order diffracted light and −1st order diffracted light caused by the diffraction phenomenon, but also in the same direction as the traveling direction of incident light. Proceeding 0th order diffracted light is generated. Therefore, originally, in order to make the parallax image visible, one light should be emitted from the diffraction grating toward an arbitrary viewpoint position, and the three lights of the + 1st order diffracted light, the −1st order diffracted light, and the 0th order diffracted light are As a result, the so-called ghost image is displayed and it becomes difficult to display a clear image.

  In this case, the applicant changes the positional relationship between the light source and the diffraction grating (the incident angle of light with respect to the diffraction grating), the optical design of the diffraction grating, etc. It has been found that it can be made smaller or not emitted from the diffraction grating. However, even if the incident angle of the light with respect to the diffraction grating and the optical design of the diffraction grating are changed, the light amount of the 0th-order diffracted light is configured to be sufficiently reduced or not emitted from the diffraction grating. It has become difficult. For this reason, in the conventional stereoscopic television, even if a configuration in which the light amount of the −1st order diffracted light is reduced or the −1st order diffracted light is not emitted from the diffraction grating is used, the ghost image is caused by the presence of the 0th order diffracted light. Is displayed, making it difficult to display a clear image.

  The present invention has been made in view of such problems, and provides a display device and a display device that can display a clear image free from a ghost image caused by zero-order diffracted light emitted from a diffraction grating. Main purpose.

  In order to achieve the above object, a display according to the present invention is a display including a light diffracting unit that diffracts light from a light source, and is an optical material capable of transmitting diffracted light emitted from the light diffracting unit. And a light reflecting portion having a reflective element provided so that the diffracted light can be incident thereon, and transmitting the first-order diffracted light of the −1st order diffracted light and the + 1st order diffracted light as the diffracted light through the reflective element. By emitting from the reflecting element, a plurality of images can be displayed so that different images can be viewed from different viewpoint positions that face the display and are different in the horizontal direction of the display. The reflection unit reflects the 0th-order diffracted light as the diffracted light at the reflective element, so that the 0th-order diffracted light at the reflective element is higher than the transmittance of any of the first-order diffracted light at the reflective element. Better transmittance of diffracted light is configured to be smaller.

  The above-mentioned “diffracting light from the light source” only diffracts light from the light source at the light diffracting unit in a configuration in which light emitted from the light source (illuminant) is directly incident on the light diffracting unit. In addition, another optical component (an optical path changing unit such as a prism or a mirror, a light modulation element, and a polarizing panel) is disposed between the light source (light emitter) and the light diffracting unit, and the light source (light emitter). In the configuration in which the light emitted from the optical component passes (transmits), or is reflected by these optical components and then enters the light diffraction section, the light that has passed (transmitted) the optical components, or This corresponds to the case where the light reflected by the optical component is diffracted by the light diffraction section. In addition, the “transmittance” described above means that “the intensity of the light emitted from the [interface on the front side of the display (one side opposite to the light diffraction part side) in the reflective element] (the amount of emitted light) It means a value divided by the intensity (incident light amount) of light incident on the reflecting element from the back side interface (one surface on the light diffraction part side)].

  In the display according to the present invention, the light reflecting portion is configured so that the 0th-order diffracted light is totally reflected at an interface of the reflective element on the front side of the display.

  In addition, the display device according to the present invention is configured to be able to display one display pixel with a plurality of types of color light having different wavelengths, and the light reflecting unit is configured to display each color light for displaying the one display pixel. Correspondingly, the reflective element is provided, and at least one of the optical material and the shape of the reflective element corresponding to each color light for displaying the one display pixel is different from each other.

  In addition, the display device according to the present invention is configured to be able to display one display pixel with a plurality of types of color light having different wavelengths, and the light reflecting unit is configured to display each color light for displaying the one display pixel. Correspondingly, the reflection element is provided, and the reflection elements corresponding to the respective color lights for displaying the one display pixel are formed of the same optical material and have the same shape. .

  Moreover, the display apparatus which concerns on this invention is provided with the display in any one of said, the said light source, and the control part which controls lighting of the said light source and displays the said image on the said display.

  The display according to the present invention includes a light reflecting portion having a reflecting element provided so that diffracted light can be incident by an optical material capable of transmitting diffracted light emitted from a light diffracting portion that diffracts light from a light source, and Each of the first-order diffracted light and the + 1st-order diffracted light as the diffracted light is transmitted through the reflecting element and emitted from the reflecting element, thereby facing the display and different in the left-right direction of the display A plurality of images can be displayed so that images different from each other can be visually recognized from the viewpoint position, and by reflecting the 0th-order diffracted light at the reflecting element, the diffraction at the reflecting element is higher than the transmittance of any of the first-order diffracted lights. The light reflecting portion is configured so that the transmittance of 0th-order diffracted light as light becomes smaller.

  Further, in the display according to the present invention, the light reflecting portion is configured such that the 0th-order diffracted light is totally reflected at the interface on the front surface side of the display in the reflective element.

  A display device according to the present invention includes the above-described display, a light source, and a control unit that controls lighting of the light source to display an image on the display.

  Therefore, according to the display and the display device according to the present invention, the light reflecting portion sufficiently reflects the 0th-order diffracted light and suppresses the emission of the 0th-order diffracted light to the front side of the display (display device). Due to the presence of the 0th-order diffracted light emitted from the diffractive portion, a so-called ghost image can be suppressed and a clear image can be displayed.

  According to the display device of the present invention, a reflective element is provided corresponding to each color light for displaying one display pixel, and a reflective element corresponding to each color light for displaying one display pixel is provided. By forming the light reflecting portion by forming at least one of the optical material and the shape different from each other, it is possible not only to suppress the situation where a ghost image due to the presence of the 0th-order diffracted light is displayed, Since the emission angles of the first-order diffracted light of each color emitted from the reflection unit can be made the same angle, for example, a configuration that does not include a diffusion plate for diffusing light transmitted through the light reflection unit in the vertical direction of the display In this case, it is possible to avoid a situation in which the color image is blurred in the vertical direction.

  According to the display device of the present invention, a reflective element is provided corresponding to each color light for displaying one display pixel, and a reflective element corresponding to each color light for displaying one display pixel is provided. Since the light reflecting portion is formed by using the same optical material and having the same shape, the light reflecting portion can be easily designed and manufactured. Can be reduced.

It is a block diagram which shows the structure of the display apparatus 1 (display 2). It is a top view for demonstrating the relationship between the indicator 2 (2C) and light source 3 (3C) of the display apparatus 1 (1C), and the light L5 emitted in the case of an image display. Section for explaining the relationship of the arrangement of the optical path changing panel 12 (12c), the diffraction grating panel 13 (13c), the light reflecting panel 14 (14c), the diffusion plate 15 and the light source 3 (3C) in the display 2 (2C). FIG. 3 is a front view of a light source 3. FIG. 3 is a front view of an optical path changing panel 12. FIG. 3 is a front view of a diffraction grating panel 13. FIG. It is the perspective view which looked at the diffraction grating panel 13 from diagonally upward. It is sectional drawing of the diffraction grating panel 13a which concerns on other embodiment. It is sectional drawing of the diffraction grating panel 13b which concerns on other embodiment. 2 is a front view of a light reflecting panel 14. FIG. It is sectional drawing which looked at the light reflection panel 14 from the side. It is sectional drawing of the light reflection panel 14a which concerns on other embodiment. It is sectional drawing of the light reflection panel 14b which concerns on other embodiment. It is sectional drawing which looked at the diffusion plate 15 from the side. 6 is an explanatory diagram for explaining a relationship between a normal line L15 of the panel surface F5 in the diffusion plate 15 and an incident direction of the light L2 with respect to the diffraction grating surface F3 in the diffraction grating panel 13. FIG. The relationship between the normal L15 of the panel surface F5 in the diffusion plate 15 and the incident direction of the light L2 with respect to the diffraction grating surface F3 in the diffraction grating panel 13, and the relationship between the normal L15 and the emission direction of the light L3 from the diffraction grating surface F3. FIG. 16 is an explanatory diagram for explaining the diffraction grating surface F3, the panel surface F5, the normal line L15, and the lights L2 and L3 in the direction of the arrow M in FIG. The relationship between the normal L15 of the panel surface F5 in the diffusion plate 15 and the incident direction of the light L2 with respect to the diffraction grating surface F3 in the diffraction grating panel 13, and the relationship between the normal L15 and the emission direction of the light L3 from the diffraction grating surface F3. FIG. 16 is a diagram illustrating the diffraction grating surface F3, the panel surface F5, the normal line L15, and the lights L2 and L3 in the direction of the arrow N in FIG. It is explanatory drawing for demonstrating the relationship between the normal line L15 of the panel surface F5 in the diffusion plate 15, and the normal line L13 of the diffraction grating surface F3 in the diffraction grating panel 13, Comprising: The diffraction grating surface F3, the panel surface F5, and the method It is the figure which looked at the lines L13 and L15 in the direction of the arrow M in FIG. It is another explanatory drawing for demonstrating the relationship between the normal line L15 of the panel surface F5 in the diffuser plate 15, and the normal line L13 of the diffraction grating surface F3 in the diffraction grating panel 13, Comprising: It is the diffraction grating surface F3 and the panel surface F5. It is the figure which looked at normal line L13 and L15 in the direction of the arrow N in FIG. FIG. 6 is an explanatory diagram for explaining a grating line of each diffraction grating 30 in the diffraction grating panel 13. It is explanatory drawing for demonstrating the relationship between the normal line L13 of the diffraction grating surface F3 in the diffraction grating panel 13, and the incident direction of the light L2 with respect to the diffraction grating surface F3. The relationship between the normal L13 of the diffraction grating surface F3 in the diffraction grating panel 13 and the incident direction of the light L2 with respect to the diffraction grating surface F3, and the relationship between the normal L13 and the emission direction of the light L3 from the diffraction grating surface F3 will be described. FIG. 22 is an explanatory diagram for viewing the diffraction grating surface F3, the panel surface F5, the normal line L13, and the lights L2 and L3 in the direction of the arrow M in FIG. The relationship between the normal L13 of the diffraction grating surface F3 in the diffraction grating panel 13 and the incident direction of the light L2 with respect to the diffraction grating surface F3, and the relationship between the normal L13 and the emission direction of the light L3 from the diffraction grating surface F3 will be described. FIG. 22 is another explanatory diagram for viewing the diffraction grating surface F3, the panel surface F5, the normal line L13, and the lights L2 and L3 in the direction of the arrow N in FIG. 4 is an explanatory diagram for explaining a relationship between a normal line L13 of the diffraction grating surface F3 in the diffraction grating panel 13 and an extending direction (solid line La) of each convex portion 31, and a formation pitch of each convex portion 31. FIG. FIG. 11 is another explanatory diagram for explaining the relationship between the normal line L13 of the diffraction grating surface F3 and the extending direction (solid line La) of each convex portion 31 in the diffraction grating panel 13, and the diffraction grating surface F3 and each convex portion. It is the figure which looked at the continuous line La which shows the extending direction of 31 in the direction of the arrow N shown in FIG. It is explanatory drawing for demonstrating the relationship between the normal line L13 of the diffraction grating surface F3 in the diffraction grating panel 13, and the output direction of the light L3 from the diffraction grating surface F3. It is explanatory drawing for demonstrating the relationship between the normal line L15 of the panel surface F5 in the diffusion plate 15, and the output direction of the light L3 from the diffraction grating surface F3. It is explanatory drawing for demonstrating the relationship between the + 1st order diffracted light L3b (-1st order diffracted light L3c) from the diffraction grating panel 13, and the + 1st order diffracted light L3b (-1st order diffracted light L3c) from the light reflection panel 14, It is the figure which looked at the diffraction grating panel 13 and the light reflection panel 14 in the same direction as the direction of the arrow N shown to FIG. FIG. 15 is an explanatory diagram for explaining the relationship between the 0th-order diffracted light L3a from the diffraction grating panel 13 and the 0th-order diffracted light L3a from the light reflecting panel 14, and the diffraction grating panel 13 and the light reflecting panel 14 are shown in FIGS. , 26, and 27, viewed in the same direction as the arrow N. It is a block diagram which shows the structure of the display apparatus 1C (display 2C and light source 3C) which concerns on other embodiment. It is a front view of light source 3C. It is a front view of the optical path change panel 12c. It is a front view of the diffraction grating panel 13c. It is a front view of the light reflection panel 14c. It is explanatory drawing for demonstrating the indicator 2C. It is explanatory drawing for demonstrating the other indicator 2C. It is explanatory drawing for demonstrating other display 2C. FIG. 36 is an explanatory diagram for explaining the transmittance of the + 1st order diffracted light L3b (−1st order diffracted light L3c) and the transmittance of the 0th order diffracted light L3a in the pixel E5 of the display 2C shown in FIG. It is explanatory drawing for demonstrating the transmittance | permeability of + 1st order diffracted light L3b (-1st order diffracted light L3c) in the pixel E5 of the display 2C shown in FIG. 36, and the transmittance | permeability of 0th order diffracted light L3a. FIG. 38 is an explanatory diagram for explaining the transmittance of the + 1st order diffracted light L3b (−1st order diffracted light L3c) and the transmittance of the 0th order diffracted light L3a in the pixel E5 of the display 2C shown in FIG. 37. It is a front view of the diffraction grating panel 13d which concerns on other embodiment. It is the front view which expanded one of each diffraction grating 30 in the diffraction grating panel 13d. It is sectional drawing of the diffraction grating panels 13e and 13h which concern on other embodiment. It is sectional drawing of the diffraction grating panels 13f and 13i which concern on other embodiment. It is sectional drawing of the diffraction grating panels 13g and 13j which concern on other embodiment. It is sectional drawing of the diffraction grating panel 13k which concerns on other embodiment. It is explanatory drawing for demonstrating the relationship between the incident light with respect to a diffraction grating, and the + 1st order diffracted light by a diffraction grating, a -1st order diffracted light, and a 0th order diffracted light.

  Embodiments of a display and a display device according to the present invention will be described below with reference to the accompanying drawings.

  The display device 1 shown in FIGS. 1 to 3 is a 3D display device configured to be able to display a stereoscopic image based on parallax (“a plurality of images that are different from each other from different viewpoint positions in the left-right direction of the display device. It is an example of a configuration that “can display an image”, and includes a display 2, a light source 3, and a control unit 4. In the actual display device 1, as an example, 81 types of “horizontal x” that are different from each other in 81 parallax regions defined corresponding to the respective viewpoint positions in the left and right 81 directions on the front side of the display device 1. An RGB color image of “vertical = 1920 × 1080 pixels” is configured to be visually recognized. In order to facilitate understanding of the configurations of “display” and “display device”, the left and right 81 directions will be described below. Configuration for visually recognizing 81 pixels (display pixels) corresponding to each other in 81 different types of “horizontal × vertical = 1920 × 1080 pixels” monochromatic images from each parallax region for each viewpoint position A configuration for displaying one display pixel group in a single color image group composed of 81 types of single color images will be described.

  In this case, as an example, the light source 3 has a plurality of light emitting portions (LEDs, etc.) arranged on the surface of a flat substrate corresponding to each display pixel of the stereoscopic image to be displayed, and has a flat plate shape as a whole. Is formed. Further, in the light source 3, as shown in FIG. 4, as shown in FIG. 4, “horizontal × horizontal X” is displayed in one display pixel group (a group of 81 display pixels corresponding to each other) of the single color image group. Light emitting units 10A1 to 10I9 (hereinafter, also referred to as “light emitting unit 10” when not distinguished) are provided. That is, in the light source 3 in the display device 1 configured to display a monochromatic image, one light emitting unit 10 is provided for each display pixel constituting one monochromatic image. According to the control signal S from the control unit 4, the light source 3, as shown in FIG. 3, as an example, lights perpendicular to and parallel to the panel surface F 1 (surface parallel to the substrate surface of the substrate). L1 is emitted for each light emitting unit 10.

  On the other hand, as shown in FIGS. 1 to 3, the display 2 has a front side (side on which an image viewer is present: FIGS. 1 and 3) from the back side (left side in FIGS. 1 and 3 and the upper side in FIG. 2). The optical path changing panel 12, the diffraction grating panel 13, the light reflecting panel 14, and the diffusing plate 15 are arranged in this order toward the right side in FIG. 2, the lower side in FIG. As shown in FIG. 3, in the display device 1, as an example, the panel surface F1 of the light source 3 includes the panel surface F2 of the optical path changing panel 12, each diffraction grating surface F3 of the diffraction grating panel 13, and diffusion. These are arranged so as to be parallel to the panel surface F5 of the plate 15.

  The optical path changing panel 12 is an “optical path changing unit” that changes the traveling direction of the light L1 from the light source 3, and is provided with a prism (optical path changing element) corresponding to each display pixel of the stereoscopic image to be displayed. As shown in FIG. 2, it is formed in a flat plate shape as a whole and is disposed between the light source 3 and the diffraction grating panel 13. In this case, as shown in FIG. 5, the optical path changing panel 12 is arranged with “horizontal × vertical = 9 × 9 = 81 places” prisms 20A1 to 20I9 (hereinafter also referred to as “prism 20” when not distinguished). Is provided. That is, in the display device 2 in the display device 1 configured to display a monochromatic image, one optical element 20 is provided for each of the display pixels constituting one monochromatic image, and the optical path changing panel 12 is configured. Yes. In the present specification, “one optical path changing element” means “one light emitting element” among optical elements (optical elements that refract incident light) configured to change the optical path of incident light. It means a part defined corresponding to “part”.

  Further, in the optical path changing panel 12 of this example, as an example, there is no physical boundary between the nine prisms 20 arranged in the horizontal direction, and these nine prisms 20 are continuously integrated as one prism. Is formed. Hereinafter, a prism in which a plurality of prisms 20 are integrally formed continuously is also referred to as a “prism 200”. That is, the optical path changing panel 12 is formed so that nine prisms 200-1 to 200-9 that are long in the horizontal direction are arranged in the vertical direction. In this case, in the case of adopting a configuration in which the “optical path changing elements” are prisms, the number of “optical path changing elements” that are integrally formed continuously is not limited to “9 in the horizontal direction”, but one One “prism 20” can be formed independently for each “optical path changing element”, or a plurality of “optical path changing elements” arranged in the vertical direction can be constituted by one prism 200, or a plurality can be arranged in the horizontal direction. These “optical path changing elements” and a plurality of “optical path changing elements” arranged in the vertical direction can also be configured by one prism 200.

  Further, as shown in FIG. 3, in this display device 2, the surface (panel surface F <b> 2) facing the light source 3 in the optical path changing panel 12 is formed (arranged) in parallel with the panel surface F <b> 1 of the light source 3. Each of the prisms 20 (200) is formed on the surface of the optical path changing panel 12 facing the diffraction grating panel 13 so as to form a slope that gradually protrudes toward the diffraction grating panel 13 toward the lower side ( The light L1 is configured (disposed) perpendicularly to the surface (panel surface F2) facing the light source 3 in each prism 20 (200)). In this example, a configuration is adopted in which an inclined surface is formed on the front surface of the optical path changing panel 12 (the side on which an image viewer is present) to function as a “prism”. It is also possible to adopt a configuration in which an inclined surface is formed on the side facing the light source 3 to function as a “prism” (not shown).

  In this case, in the optical path changing panel 12, all of the 81 prisms 20 (that is, the nine prisms 200 arranged in the vertical direction) are formed of the same optical material and have the same shape. Yes. Specifically, in this optical path changing panel 12, each prism 20 (200) is the same type of “resin material having optical transparency (for example, polymethyl methacrylate, polycarbonate, polypropylene, PET resin, etc.)” The prisms are formed so that the apex angle (angle θp shown in FIG. 3) is 40 °. This optical path changing panel 12 changes the traveling direction of the light L1 emitted from each light emitting part 10 of the light source 3 to the vertical direction (vertical direction) of the display 2 by each prism 20, and the diffraction grating panel 13 described later. The light L2 is obliquely incident on each of the diffraction grating surfaces F3. In this case, since the “optical path changing element” is composed of the prism 20 (200), the “optical path changing portion” can be easily manufactured using a resin material, glass, or the like. It is possible to reduce.

  The diffraction grating panel 13 is an example of a “light diffracting unit”. As shown in FIG. 3, the diffraction grating panel 13 diffracts the light L2 emitted from the light source 3 and whose optical path is changed by the optical path changing panel 12, and + 1st order diffracted light L3b (or -1st order diffracted light L3c) is emitted. In this case, the diffraction grating panel 13 also emits the 0th-order diffracted light L3a when diffracting the light L2. In the following description, when the 0th-order diffracted light L3a, the + 1st-order diffracted light L3b, and the -1st-order diffracted light L3c are not distinguished, they are also referred to as light L3. In this diffraction grating panel 13, as shown in FIG. 6, “horizontal” is displayed corresponding to the display pixel of the stereoscopic image to be displayed on the part for displaying one display pixel group of the monochromatic image group. X vertical = 9 x 9 = 81 "diffraction gratings 30A1 to 30I9 (hereinafter also referred to as" diffraction grating 30 "when not distinguished) are formed (one diffraction grating is formed for each display pixel) Example).

  In the present specification, “one diffraction grating” means a portion defined corresponding to “one light emitting portion” among optical elements configured to be able to diffract incident light. In this case, in the diffraction grating panel 13 in the display device 2 configured to display a monochromatic image, one diffraction grating 30 is defined corresponding to one light emitting unit 10 in the light source 3, and one monochromatic image is obtained. One diffraction grating 30 is defined for each of the display pixels constituting the. In FIG. 6, the grating lines of each diffraction grating 30 are shown at a pitch wider than the actual grating formation pitch. As shown in FIG. 7, the diffraction grating panel 13 is configured to diffract and emit the light L2 from the optical path changing panel 12 in each of the predetermined 81 directions for each diffraction grating 30. In FIG. 7, the directions in which the light L2 is diffracted and emitted are indicated by arrows.

  In this case, as shown in FIG. 3, the diffraction grating panel 13 has, as an example, each formation region of each diffraction grating 30 defined on the surface facing the optical path changing panel 12 (that is, the back surface of the diffraction grating panel 13). A concavo-convex pattern (lattice pattern) is formed in which a plurality of convex portions 31 that are linear in plan view and a plurality of concave portions 32 that are linear in plan view are formed at a predetermined pitch. Functions as a phase type diffraction grating 30, and is configured to diffract the light L2 from the optical path changing panel 12 in a predetermined direction. In addition, in this example, although the structure which makes the uneven | corrugated pattern formed in the back surface of the diffraction grating panel 13 function as the diffraction grating 30 is employ | adopted, the front side of the diffraction grating panel 13 (side where the person who visually recognizes an image exists) It is also possible to adopt a configuration in which a concavo-convex pattern is formed on the substrate to function as a diffraction grating (not shown).

  In the present specification, a surface including each center line in the width direction (vertical direction in FIG. 3) of each protrusion 31 constituting the diffraction grating 30 in the diffraction grating panel 13 (each center 31o in FIG. (Including plane) is defined as a diffraction grating plane F3. Further, even when the cross-sectional shape of the convex portion 31 is different from the diffraction grating panel 13 as in the diffraction grating panel 13a shown in FIG. 8 or the diffraction grating panel 13b shown in FIG. A surface including each center line in the width direction on the protruding end surface of each convex portion 31 (a surface including each center 31o in the figure) is defined as a diffraction grating surface F3. Furthermore, in the following description, the center line or a line segment parallel to the center line (a line indicated by a solid line Lb in FIG. 20 and the like) is also referred to as a lattice line.

  In this case, as shown in FIG. 3, an optical path in which each prism 20 is configured by forming a slope in a direction gradually projecting toward the diffraction grating panel 13 toward the lower side on the surface facing the diffraction grating panel 13. In the display 2 having the change panel 12, the light L1 from the light source 3 is refracted downward and is incident on the diffraction grating panel 13 (the diffraction grating surface F3 of each diffraction grating 30) as light L2. Therefore, in this display device 2, the incident position of the light L 2 emitted from the optical path changing panel 12 on the diffraction grating panel 13 is the incident position of the light L 1 on the optical path changing panel 12 or the outgoing light L 2 from the optical path changing panel 12. The position is shifted below the position. For this reason, in the display device 2, the diffraction grating 30 of the diffraction grating panel 13 is arranged so as to be displaced downward with respect to the light emitting units 10 of the light source 3 and the prisms 20 of the optical path changing panel 12. Is adopted.

  The light reflecting panel 14 is an example of a “light reflecting portion”, and transmits the + 1st order diffracted light L3b (or −1st order diffracted light L3c) emitted from the diffraction grating panel 13 and emits it to the diffusion plate 15 side. At the same time, the transmission of the 0th-order diffracted light L3a to the diffusion plate 15 side is suppressed by reflecting the 0th-order diffracted light L3a and emitting it from the vertical end face of the light reflecting panel 14 or the surface on the diffraction grating panel 13 side. To do. The light reflecting panel 14 is provided with a prism (an example of a “reflecting element”) corresponding to each display pixel of a stereoscopic image to be displayed, and is formed in a flat plate shape as shown in FIG. The diffraction grating panel 13 and the diffusion plate 15 are disposed.

  In this case, as shown in FIG. 10, prisms 40 </ b> A <b> 1 to 40 </ b> I <b> 9 (hereinafter also referred to as “prisms 40” when not distinguished) are arranged on the light reflecting panel 14. Is provided. That is, in the display device 2 in the display device 1 configured to display a monochromatic image, the light reflecting panel 14 is configured by providing one prism 40 for each of the display pixels constituting one monochromatic image. Yes. In this specification, “one reflective element” refers to a portion defined corresponding to “one light emitting portion” among optical elements configured to reflect incident zeroth-order diffracted light L3a. means.

  Moreover, in this light reflection panel 14, as an example, there is no physical boundary between the nine prisms 40 arranged in the horizontal direction, and the nine prisms 40 are integrally formed continuously as one prism. ing. Hereinafter, a prism in which a plurality of prisms 40 are integrally and continuously formed is also referred to as “prism 400”. That is, the light reflecting panel 14 is formed so that nine prisms 400-1 to 400-9 that are long in the horizontal direction are arranged in the vertical direction. In this case, in the case of adopting a configuration in which the “reflecting elements” are prisms, the number of “reflecting elements” that are integrally formed continuously is not limited to “9 in the horizontal direction”, but one “reflecting element”. One prism 40 can be formed independently for each element, or a plurality of “reflecting elements” arranged in the vertical direction can be formed by one prism 400, or a plurality of “reflecting elements” arranged in the horizontal direction can be formed. ”And a plurality of“ reflective elements ”arranged in the vertical direction can be configured by one prism 400.

  Further, as shown in FIG. 11, in this light reflecting panel 14, as an example, the surface of the light reflecting panel 14 facing the diffraction grating panel 13 (interface F4a: “interface on the back side of the display”): The left surface in FIG. 4 is formed with a slope that gradually protrudes toward the diffraction grating panel 13 toward the upper side, and a surface facing the diffusion plate 15 in the light reflecting panel 14 (interface F4b: “display”). An example of the “front-side interface”: the right side surface in the same figure) is formed with an inclined surface that gradually protrudes toward the diffusion plate 15 toward the lower side, thereby constituting each prism 40 (400). In addition, like the light reflection panel 14a shown in FIG. 12, the facing surface (interface F4a) with the diffraction grating panel 13 is formed in parallel with the diffraction grating surface F3 of the diffraction grating panel 13, and the facing surface with the diffusion plate 15. It is also possible to employ a configuration in which a slope that gradually protrudes toward the diffusion plate 15 side is formed on the (interface F4b) so as to function as the prism 40 (400). Further, as in the light reflecting panel 14b shown in FIG. 13, a slope is formed on the surface facing the diffraction grating panel 13 (interface F4a) so as to gradually protrude toward the diffraction grating panel 13 toward the lower side. Further, it is also possible to adopt a configuration in which a slope that gradually protrudes toward the diffusion plate 15 side is formed on the surface facing the diffusion plate 15 (interface F4b) so as to function as the prism 40 (400). .

  In the light reflecting panels 14, 14a, and 14b, all of the 81 prisms 40 (that is, the nine prisms 400 arranged in the vertical direction) are the same type of optical material (“resin material having light transmission property: as an example). , Polymethyl methacrylate, polycarbonate, polypropylene, PET resin, etc.) ”and are formed to have the same shape. In this case, since the “reflecting element” is composed of the prism 40 (400), the “light reflecting portion” can be easily manufactured using a resin material, glass, or the like, and thus the manufacturing cost of the display 2 is sufficiently reduced. It is possible to do. The incident angle of the light L3 with respect to each prism 40 (400) of the light reflecting panels 14, 14a, 14b, the emission (reflection) angle of the light L3 from the light reflecting panel 14, and the angles θa, F of the interfaces F4a, F4b described above. The relationship between θb and the refractive index of the optical material constituting the light reflecting panels 14, 14a, 14b will be described in detail later.

  The diffusion plate 15 is an example of a “light transmission panel”, and is a “light diffusion unit” that diffuses the light L3 transmitted through the light reflection panel 14 in the vertical direction of the display 2. It is composed of a lenticular lens formed in a flat plate shape with a resin material. As shown in FIG. 14, as an example, the diffusion plate 15 has a plurality of convex lenses that are long in the lateral direction on the front surface side (side on which a person who views an image is present). In addition, in the display device 2, as an example, the diffusing plate 15 is configured by forming the convex lens so that a plurality of convex lenses are positioned per one diffraction grating 30 in the diffraction grating panel 13. Thereby, in this display device 2, the light L3 transmitted through the light reflecting panel 14 is transmitted through the diffusion plate 15, diffused in the vertical direction (vertical direction) by each convex lens, and emitted as light L5.

  In this case, in this specification, the surface of the diffusion plate 15 that faces the diffraction grating panel 13 (that is, the back surface of the diffusion plate 15) is referred to as a panel surface F5. The “diffusing plate” may be formed by forming a concave lens instead of the convex lens (not shown). In addition, a plurality of convex lenses or a plurality of concave lenses can be formed on the back side (the side of the surface facing the light reflection panel 14) (not shown). In this case, when a configuration in which a convex lens or a concave lens is formed on the back side is adopted, the front surface of the diffuser plate is defined as a panel surface F5.

  In the display device 2, as will be described later, the normal line of the panel surface F2 of the optical path changing panel 12, the normal line of each diffraction grating surface F3 of the diffraction grating panel 13, and the normal line of the panel surface F5 of the diffusion plate 15 are parallel. The light L1 is emitted from each light emitting portion 10 of the light source 3 in any direction. Further, in the display device 2, the light L1 emitted from the light source 3 is refracted in the vertical direction (downward in this example) by each prism 20 of the optical path changing panel 12, and is emitted from the optical path changing panel 12 as light L2. As shown in FIG. 3, it is configured to be incident obliquely on the diffraction grating surface F3 of the diffraction grating 30. Furthermore, in this example, the optical path changing panel 12 and the diffraction grating panel 13 are configured so that one of the + 1st order diffracted light L3b and the −1st order diffracted light L3c is not emitted from the diffraction grating panel 13 (hereinafter referred to as a diffraction grating panel). 13 will be described as + 1st order diffracted light L3b (an example of “any one order diffracted light” is emitted and −1st order diffracted light L3c is not emitted). In this example, the 0th-order diffracted light L3a emitted from the diffraction grating panel 13 and incident on each prism 40 of the light reflecting panel 14 from the interface F4a is totally reflected at the interface F4b in each prism 40, and thus the 0th-order diffracted light. A configuration is adopted in which L3a is not emitted to the diffusion plate 15 side.

  On the other hand, the control unit 4 outputs the control signal S to the light source 3 in accordance with the image data of the stereoscopic image to be displayed on the display device 2, thereby causing each light emitting unit 10 in the light source 3 to each of the stereoscopic images. Lights up according to the brightness of the display pixel. Note that the actual display device 1 includes an image processing unit that processes image data and image signals output from an external device, and the control unit 4 displays based on the data and signals processed by the image processing unit. Although the stereoscopic image is displayed on the display 2, in order to facilitate understanding of the “display” and the “display device”, description and illustration regarding the constituent elements other than the display 2, the light source 3, and the control unit 4 are omitted. To do.

  When the stereoscopic image is displayed by the display device 1 (display device 2), the control unit 4 outputs a control signal S to the light source 3, whereby the brightness corresponding to the brightness of each display pixel of the stereoscopic image to be displayed. Now, each light emitting unit 10 is turned on. At this time, as shown in FIG. 3, each light L1 emitted from each light emitting portion 10 of the light source 3 in a direction parallel to the normal line of the diffraction grating surface F3 of each diffraction grating 30 in the diffraction grating panel 13 is emitted. The light is refracted when passing through each prism 20 of the optical path changing panel 12. As a result, the refracted light L2 is incident obliquely on the diffraction grating surface F3 of the diffraction grating panel 13. Further, the light L2 incident on the diffraction grating panel 13 (diffraction grating surface F3) is diffracted by each diffraction grating 30 and emitted as light L3 (diffracted light). At this time, in this display device 1, the diffraction line 30 in the diffraction grating panel 13 defines the inclination of the grating line, the formation pitch of the convex portions 31, and the like according to the direction in which each light L 3 should be emitted. Is formed. As a result, as shown in FIG. 7, the light L3 from each diffraction grating 30 is emitted from the diffraction grating panel 13 so as to spread radially in the left and right 81 directions at predetermined intervals.

  At this time, in the display 2, as described above, the light L 1 from the light source 3 is refracted by each prism 20 in the optical path changing panel 12, and this light L 2 is reflected in each diffraction grating 30 of the diffraction grating panel 13. The optical characteristics (material and shape (prism angle)) of the optical path changing panel 12 and the positional relationship between the optical path changing panel 12 and the diffraction grating panel 13 so as to be incident obliquely on the diffraction grating surface F3. Is defined and configured. Therefore, in the display 2, when the light L2 from the optical path changing panel 12 is diffracted by the diffraction grating 30 of the diffraction grating panel 13, the intensity of the + 1st order diffracted light L3b is sufficiently increased, as shown in FIG. In addition, the −1st order diffracted light L3b and the 0th order diffracted light L3a are emitted to the light reflecting panel 14 side without the −1st order diffracted light L3c being emitted from the diffraction grating panel 13 to the light reflecting panel 14 side. For this reason, in the display 2, the use efficiency of the light L1 from the light source 3 is sufficiently improved, and the + 1st order diffracted light L3b having a sufficiently large amount of light is used as light for visually recognizing a stereoscopic image. Thus, the display pixel corresponding to the + 1st order diffracted light L3b is viewed sufficiently brightly.

  Of the + 1st order diffracted light L3b and 0th order diffracted light L3a emitted from the diffraction grating panel 13, the + 1st order diffracted light L3b is incident on each prism 40 (400) of the light reflecting panel 14 from the interface F4a. The light passes through the prism 40 (400), is emitted from the interface F4b, and enters the diffusion plate 15. On the other hand, the 0th-order diffracted light L3a is incident on each prism 40 (400) from the interface F4a of the light reflecting panel 14 and totally reflected at the interface F4b. Further, the 0th-order diffracted light L3a totally reflected at the interface F4b travels toward the interface F4a, and is totally reflected at the interface F4a as an example. In this way, the 0th-order diffracted light L3a incident on each prism 40 (400) from the interface F4a is sequentially totally reflected at the interface F4b and the interface F4a and travels through the light reflecting panel 14, and finally, The light is emitted to the outside of the light reflection panel 14 from an end portion in the vertical direction (or an end portion in the left-right direction) in the light reflection panel 14.

  In the above example, the 0th-order diffracted light L3a has been described as being emitted from the end in the vertical direction (or left-right direction) in the light reflecting panel 14 through a plurality of total reflections at the interfaces F4a and F4b. However, depending on the optical design of each prism 40 (400) (the angles θa and θb of the interfaces F4a and F4b and the refractive index of the optical material constituting them), after the first total reflection at the interface F4b, or the interface Immediately after the first total reflection at F4a, the light is emitted from the end in the vertical direction (or left-right direction), or when entering the interface F4b, a part of the light is emitted from the interface F4b to the diffusion plate 15 side, When the light enters the interface F4a, a part of the light is emitted from the interface F4a to the diffraction grating panel 13 side. However, by reflecting at least part of the 0th-order diffracted light L3a at each prism 40 (400), the transmittance of the 0th-order diffracted light L3a at each prism 40 (400) is more than the transmittance of the + 1st-order diffracted light L3b at each prism 40 (400). In this display device 2 including the light reflection panel 14 configured so that the transmittance is smaller, there is no ghost image due to the 0th-order diffracted light L3a emitted from the diffraction grating panel 13, or the ghost A clear image in which the image is difficult to be visually recognized is visually recognized.

  On the other hand, the + 1st order diffracted light L3b emitted from the light reflecting panel 14 is diffused in the vertical direction by the lenticular lens constituting the diffusion plate 15 as shown in FIGS. 3 and 14, and as shown in both figures and FIG. The light is emitted as light L5 toward the front of the display 2 (display device 1). Thereby, the viewing area in the vertical direction (vertical direction) is expanded for each parallax area in the left and right 81 directions, and within a predetermined height range in the vertical direction for each position in the left and right 81 directions in front of the display device 1. An image corresponding to each viewpoint position (an image having each light L5 as a display pixel) is visually recognized.

  Therefore, in a state where the left eye and the right eye of the person viewing the image are located in different parallax regions (viewpoint positions), the parallax image viewed by the left eye and the parallax image viewed by the right eye are Since they differ depending on the position, the displayed image is recognized as a stereoscopic image (recognized as a stereoscopic image by binocular parallax). In addition, each person viewing the image visually recognizes the image displayed on the display device 1 (display 2), and each parallax region (each viewpoint position) in the directions (left and right directions) of arrows A1 and A2 shown in FIG. The images displayed on the display device 1 (display device 2) are recognized as stereoscopic images by motion parallax.

  Next, the relationship between the diffraction grating surface F3 of the diffraction grating panel 13 and the panel surface F5 of the diffusion plate 15 in the display 2 and the light L2 from the optical path changing panel 12 and the light L3 diffracted by the diffraction grating panel 13 is shown. , And the incident angle of the light L3 with respect to each prism 40 (400) of the light reflecting panel 14, the angles θa and θb of the interfaces F4a and F4b of each prism 40 (400), the refractive index of the prism 40 (400), and the prism 40 The relationship between the emission angles of the 0th-order diffracted light L3a and the + 1st-order diffracted light L3b from (400) will be described with reference to the drawings.

  In order to facilitate the understanding of the transmission and reflection of the light L3 by the prisms 40 (400) of the light reflecting panel 14, first, a display device having a configuration in which the light reflecting panel 14 does not exist in the display device 2 described above. Hereinafter, in order to distinguish from the display device 2 described above, a display device in which the light reflection panel 14 does not exist is assumed to be referred to as “display device 2A”, and thereafter, the light reflection panel 14 (the prism 40 (400 )), How the optical path of the light L3 (+ 1st order diffracted light L3b (or −1st order diffracted light L3c) or 0th order diffracted light L3a) is changed will be described. Therefore, in FIG. 15, 21, 26, 27, etc., illustration of the light reflection panel 14 (interfaces F4a, F4b) is omitted. The display 2 and 2A configured with the diffusion plate 15 will be described as an example. In the display configured with a “light transmissive panel” other than the “diffusion plate (light diffusion unit)”. The “light transmissive panel” and “light transmissive panel surface” in the display device correspond to “diffuser plate 15” and “panel surface F5” in the following description.

In this display 2A, an X component (diffusion) at an angle formed between the normal line L15 of the panel surface F5 of the diffusion plate 15 and the incident direction of the light L2 incident on the diffraction grating surface F3 of each diffraction grating 30 of the diffraction grating panel 13 is used. It is a component corresponding to the horizontal direction in the plate 15, and when viewed from the surface on which the light L2 is incident, the angle when the incident direction of the light L2 intersects the panel surface F5 obliquely rightward is defined as plus. , The angle in which the incident direction of the light L2 intersects obliquely leftward with respect to the panel surface F5 is defined as “αX (see FIGS. 15 and 16)”.
The normal line L15 of the panel surface F5 in the diffusion plate 15 (the normal line of the light transmission panel surface in the light transmission panel) and the incident direction of the light L2 incident on the diffraction grating surface F3 of each diffraction grating 30 in the diffraction grating panel 13 The Y component at the angle formed (a component corresponding to the vertical direction (vertical direction) of the diffusion plate 15, and when viewed from the surface on which the light L 2 is incident, the incident direction of the light L 2 is relative to the panel surface F 5. “ΑY (see FIGS. 15 and 17)” is an angle in which the angle of the state where the light L2 intersects obliquely downward is positive, and the angle in which the incident direction of the light L2 intersects the panel surface F5 obliquely upward is negative. ,
X component at the inclination angle of the normal line L13 of the diffraction grating surface F3 with respect to the normal line L15 of the panel surface F5 (a component corresponding to the horizontal direction of the diffuser plate 15 when viewed from the surface on the side where the light L2 is incident. The angle in a state where the normal line L13 of the diffraction grating surface F3 intersects the panel surface F5 obliquely to the left is positive, and the normal line L13 of the diffraction grating surface F3 intersects the panel surface F5 obliquely to the right. The angle that makes the angle negative is “γX (see FIG. 18)”,
From the Y component (a component corresponding to the vertical direction (vertical direction) of the diffusing plate 15 and the light L2 incident side) in the inclination angle of the normal line L13 of the diffraction grating surface F3 with respect to the normal line L15 of the panel surface F5 When viewed, the angle in a state where the normal line L13 of the diffraction grating surface F3 intersects diagonally upward with respect to the panel surface F5 is positive, and the normal line L13 of the diffraction grating surface F3 is diagonally downward with respect to the panel surface F5. The angle in which the angle of the intersecting state is minus) is “γY (see FIG. 19)”,
The perist rotation angle (the line indicated by the solid line Lb in FIG. 20) of each grating in the diffraction grating surface F3 of the diffraction grating 30 in the diffraction grating plane F3 is horizontal when viewed from the surface on the light L2 incident side. (A state parallel to the line indicated by the solid line Lc in FIG. 20) is 0 degree, the rotation angle at which the lattice line of each lattice is downwardly inclined is positive, and the rotational angle at which the lattice line of each lattice is downwardly downward is negative. Angle) is “ε (see FIG. 20)”.
The x component (the extension direction of the grating line of each grating in the diffraction grating 30 (the perist rotation angle is 0 degree) between the normal line L13 of the diffraction grating surface F3 and the incident direction of the light L2 incident on the diffraction grating surface F3. In the diffraction grating surface F3 on which the diffraction grating 30 is formed, the light L2 is a component corresponding to the left and right direction) and viewed from the surface on which the light L2 is incident. The angle in the state of entering obliquely rightward (direction in the case of the diffraction grating 30 with a perist rotation angle of 0 degree) is positive, and the light L2 is obliquely leftward with respect to the diffraction grating surface F3 (a diffraction grating with a perist rotation angle of 0 degree). “Αx (see FIGS. 21 and 22)” which is an angle in which the incident angle in the direction 30 is negative), the normal line L13 of the diffraction grating surface F3, and the diffraction grating surface F3. With the incident direction of the light L2 The y component at the angle (the direction perpendicular to the grating line of each grating in the diffraction grating 30 in the diffraction grating surface F3 (on the diffraction grating surface F3 on which the diffraction grating 30 having a perist rotation angle of 0 degrees is formed, The light L2 is obliquely downward with respect to the diffraction grating surface F3 (when the diffraction grating 30 has a perist rotation angle of 0 degree), as viewed from the surface on the light incident side. The angle of the incident state in the direction) is positive, and the angle of the state in which the light L2 is incident obliquely upward with respect to the diffraction grating plane F3 (the direction in the case of the diffraction grating 30 having a perist rotation angle of 0 degrees) is negative. “Αy (see FIGS. 21 and 23)”, which is an angle, is expressed by the following two expressions.

αx = tan-1 (tan (αX + γX) · cosε) + tan-1 (tan (αY + γY) · sin (−ε))
αy = tan−1 (tan (αX + γX) · sinε) + tan−1 (tan (αY + γY) · cosε)

Further, the order of the diffracted light is “n”, the wavelength of the light L1 is “λ”, and the grating interval of the diffraction grating 30 (grating formation pitch in the diffraction grating 30: in this example, the formation pitch of the protrusions 31) is set. “D (see FIG. 24)”
The y component (diffraction grating surface F3 with respect to the grating line of each grating in diffraction grating 30) in the inclination angle of the extending direction of each protrusion 31 (the direction indicated by solid line La in FIG. 24) with respect to normal L13 of diffraction grating surface F3 When viewed from the surface on the side on which the light L2 is incident, the component corresponding to the direction orthogonal to the inside (the vertical direction in the diffraction grating surface F3 on which the diffraction grating 30 with a perist rotation angle of 0 degrees is formed). In addition, the angle of the state in which the extending direction of the convex portion 31 intersects obliquely upward with respect to the diffraction grating surface F3 is a plus, and the state in which the extending direction of the convex portion 31 intersects obliquely downward with respect to the diffraction grating surface F3 When the angle is set to “δy (see FIGS. 24 and 25)”,
The x component at the angle formed by the normal line L13 of the diffraction grating surface F3 and the emission direction of the light L3 emitted from the diffraction grating surface F3 (the extension direction of the grating lines of each grating in the diffraction grating 30 (the perist rotation angle is 0 degree) The diffraction grating surface F3 on which the diffraction grating 30 is formed is a component corresponding to the left and right direction, and obliquely leftward from the diffraction grating surface F3 when viewed from the surface on which the light L2 is incident (perist rotation) The angle in the state in which the light L3 is emitted in the direction of the diffraction grating 30 with an angle of 0 degrees is a plus, and is diagonally rightward from the diffraction grating surface F3 (the direction in the case of the diffraction grating 30 with a perist rotation angle of 0 degrees). “Βx (see FIGS. 26 and 22)”, which is a negative angle of the state in which the light L3 is emitted, and the normal line L13 of the diffraction grating surface F3 and the light L3 emitted from the diffraction grating surface F3. With direction The y component in degrees (the direction perpendicular to the grating line of each grating in the diffraction grating 30 in the diffraction grating surface F3 (in the diffraction grating surface F3 on which the diffraction grating 30 having a perist rotation angle of 0 degrees is formed, the vertical direction) ), And when viewed from the surface on which the light L2 is incident, the light L3 is obliquely upward from the diffraction grating surface F3 (the direction in the case of the diffraction grating 30 having a perist rotation angle of 0 degrees). The angle in which the light is emitted is positive, and the angle in which the light L3 is emitted obliquely downward from the diffraction grating surface F3 (the direction in the case of the diffraction grating 30 having a perist rotation angle of 0 degrees) is negative. “βy (see FIGS. 26 and 23)” is expressed by the following two equations.

βx = −αx
βy = sin−1 {(nλ−d · sin αy) / d}

  As is apparent from the above two equations, “βx”, which is an x component in the angle formed by the normal line L13 of the diffraction grating surface F3 and the emission direction of the light L3 emitted from the diffraction grating surface F3, “Βy”, which is the y component at the angle formed by the normal line L13 of the surface F3 and the emission direction of the light L3 emitted from the diffraction grating surface F3, is the extending direction of each convex portion 31 with respect to the normal line L13 of the diffraction grating surface F3. It does not depend on “δy”, which is the y component in the inclination angle.

  Further, an X component at an angle formed by the normal line L15 of the panel surface F5 and the emission direction of the light L3 emitted from the diffraction grating surface F3 (a component corresponding to the horizontal direction of the diffusion plate 15, where the light L3 is the diffusion plate). 15, the angle of the state in which the emission direction of the light L <b> 3 intersects obliquely leftward with respect to the diffusion plate 15 when viewed from the surface on the incident side toward the direction 15 is positive, and the emission direction of the light L <b> 3 is relative to the diffusion plate 15. “ΒX (see FIGS. 27 and 16)”, which is an angle that crosses diagonally rightward, and the normal line L15 of the panel surface F5 and the light L3 emitted from the diffraction grating surface F3. Y component in the angle formed by the direction (a component corresponding to the vertical direction (vertical direction) in the diffusion plate 15, and when viewed from the surface on the side where the light L 3 is incident on the diffusion plate 15), the emission direction of the light L 3 Is against the diffusion plate 15 “ΒY (see FIGS. 27 and 17)” is an angle in which the angle of the state of crossing obliquely upward is positive and the angle of the state in which the emission direction of the light L3 crosses obliquely downward is negative). Is expressed by the following two equations.

βX = tan-1 (tanβx · cosε) + tan-1 (tanβy · sinε) + γX
βY = tan−1 (tan βx · sin (−ε)) + tan−1 (tan βy · cosε) + γY

  Therefore, when designing the display 2A (2), the light L2 (refracted by the optical path changing panel 12 based on the above six formulas so that the above-mentioned “βX” and “βY” have desired angles. “ΑX”, “αY”, “ε”, “d”, “γX”, and “γY” may be appropriately adjusted in accordance with “λ” of the light L2) incident on the diffraction grating panel 13. In this case, as the absolute value of “αy” becomes larger than 0 °, the −1st order diffracted light L3c (or the + 1st order diffracted light L3b) decreases, and the light is not emitted when the condition described later is satisfied. Further, the + 1st order diffracted light L3b (or the −1st order diffracted light L3c) increases as the −1st order diffracted light L3c (or + 1st order diffracted light L3b) decreases.

  15 to 17, 21 to 23, 26, and 27, in order to facilitate understanding of “X component”, “Y component”, “x component”, “y component”, and the like in the above explanation items. The relationship between the incident direction of the light L2 with respect to the diffraction grating surface F3, the emission direction of the light L3 from the diffraction grating surface F3, and the incident direction of the light L3 with respect to the panel surface F5, and the actual light path in the display 2A Are shown in different states. 15 to 17, 21 to 23, 26, and 27, as an example, “Pelist rotation angle ε ≠ 0 °” and “inclination angle of normal line L13 of diffraction grating surface F3 with respect to normal line L15 of panel surface F5” Is 0 ° (γX = 0 °, γY = 0 °) ”.

  On the other hand, as described above, in the display device 2, the light reflection panel 14 is disposed between the diffraction grating panel 13 and the diffusion plate 15. Therefore, the light L3 emitted from the diffraction grating panel 13 in the display 2A is incident on the light reflecting panel 14 before entering the diffusion plate 15. Specifically, the + 1st order diffracted light L3b (or −1st order diffracted light L3c) emitted from the diffraction grating panel 13 is a layer (for example, an air layer) between the diffraction grating panel 13 and the light reflecting panel 14. Is incident on the interface F4a of the light reflection panel 14, passes through the light reflection panel 14, and then exits from the interface F4b to a layer between the light reflection panel 14 and the diffusion plate 15 (for example, an air layer). As a result, the light enters the diffusion plate 15. On the other hand, as described above, when the light L2 from the optical path changing panel 12 enters the diffraction grating panel 13, not only the + 1st order diffracted light L3b (or -1st order diffracted light L3c) but also the 0th order diffracted light L3a 13 is emitted.

  In this case, the refraction of light occurs on the surface (interface) where a substance (gas, liquid, solid) having a different refractive index contacts, such as the interfaces F4a and F4b. Specifically, the incident angle of light with respect to the interface is “θi”, the outgoing angle of light from the interface is “θo”, the refractive index of the substance on the incident side of the interface is “ni”, and the outgoing angle of the interface is When the refractive index of the substance is “no”, the equation “ni · sin θi = no · sin θo” holds.

For this reason, as shown in FIGS. 28 and 29, the Y component at the angle formed by the emission direction of the light L3 emitted from the diffraction grating surface F3 and the normal line L15 of the panel surface F5 is expressed as “β ₁ Y (display 2A). “Same direction as“ βY ”described)”
The Y component at the angle formed by the normal line L14a of the interface F4a of the prism 40 (400) in the light reflecting panel 14 and the normal line L15 of the panel surface F5 of the diffusion plate 15 is defined as “θa”.
The Y component at the angle formed by the normal L14b of the interface F4b of the prism 40 (400) in the light reflecting panel 14 and the normal L15 of the panel surface F5 is “θb”.
The Y component at the angle formed by the normal L14a of the interface F4a and the incident direction of the light L3 incident on the interface F4a is “θ1”.
The Y component at the angle between the traveling direction of the light entering the prism 40 (400) from the interface F4a and traveling toward the interface F4b and the normal L14a of the interface F4a is “θ2”.
The Y component at the angle formed by the traveling direction of the light entering the prism 40 (400) from the interface F4a and traveling toward the interface F4b and the normal L14b of the interface F4b is “θ3”.
The Y component at the angle formed by the normal L14b of the interface F4b and the emission direction of the light L3 emitted from the interface F4b is “θ4”.
The refractive index of the layer between the diffraction grating panel 13 and the light reflecting panel 14 is “n1”,
The refractive index of the optical material constituting the prism 40 (400) is “n2”,
When the refractive index of the layer between the light reflection panel 14 and the diffusion plate 15 is “n3”,
Since the Y component at the angle formed by the normal L15 of the panel surface F5 and the emission direction of the light L3 is “θ4” + “θb”, the Y component “β ₂ Y” is expressed by the following equation. .

β ₂ Y = sin−1 ((sin ((sin−1 ((sin (β ₁ Y−θa)) n1 / n2)) − θb + θa)) n2 / n3) + θb

Therefore, when designing the display 2, the light L3 (+ 1st order diffracted light L3b or −1st order diffracted light L3c) to be emitted from the light reflecting panel 14 is incident on the diffusion plate 15 at a desired angle “β _2. In addition to “αX”, “αY”, “ε”, “d”, “γX”, and “γY” described above, based on the above formula, “θa”, “θb”, “N1”, “n2”, and “n3” may be appropriately adjusted.

  Further, in order to prevent the ghost image due to the presence of the 0th-order diffracted light L3a from being displayed, the 0th-order diffracted light L3a is not emitted from the light reflecting panel 14, but is entirely emitted at the interface F4b of each prism 40 (400) of the light reflecting panel 14. What is necessary is just to reflect. In this case, the condition that total reflection of light occurs at the interface such as the interface F4b or the interface F4a is the conditional expression “θi> sin−1 (no / ni)” under the condition “ni> no”. Is when In the light reflecting panel 14, the interface F4b satisfies the condition “ni> no”. Accordingly, in order to totally reflect the light incident on the prism 40 (400) from the interface F4a at the interface F4b, the following conditional expression is satisfied as “θi = θ3”, “no = n3”, and “ni = n2”. Thus, the light reflecting panel 14 (prism 40 (400)) may be designed and manufactured.

sin-1 ((sin ([alpha] Y + [theta] a)) n1 / n2) + [theta] b- [theta] a> sin-1 (n3 / n2)

  Next, a configuration for displaying a color image by the display device 1 will be described with reference to the drawings.

  In addition, in order to distinguish from the structure of the display apparatus 1 for displaying said monochromatic image, the display apparatus 1 which can display a color image is called display apparatus 1C. The display 2 and the light source 3 in the display device 1C are referred to as a display 2C and a light source 3C in order to distinguish them from the display 2 and the light source 3 in the display device 1. Further, the optical path changing panel 12, the diffraction grating panel 13 and the light reflecting panel 14 in the display 2C are distinguished from the optical path changing panel 12, the diffraction grating panel 13 and the light reflecting panel 14 in the display 2 for displaying a monochromatic image. Further, they are referred to as an optical path changing panel 12c, a diffraction grating panel 13c, and a light reflecting panel 14c. In addition, constituent elements having the same functions as those of the display device 1 for displaying a monochromatic image among other constituent elements are given the same reference numerals and redundant description is omitted.

  When a color image is displayed by this type of display device, a plurality of color lights (for example, R = Red = red, G = Green = green, B = Blue = blue, for each display pixel constituting the color image) The color of each display pixel is made visible as an arbitrary color by synthesizing the three color lights (hereinafter also simply referred to as “R, G, B”). In this case, when R, G, B light for displaying one display pixel is incident on the same prism in the same direction, the wavelength λ is caused by the wavelength dependence of the photorefractive phenomenon. Thus, the emission angle from the prism and the reflection angle at the interface are different for each of the different color lights. In addition, when R, G, and B light beams for displaying one display pixel are incident on the diffraction grating surface of the same diffraction grating in the same direction, due to the wavelength dependence of the diffraction phenomenon. In this state, the diffraction angles of the respective color lights having different wavelengths λ are different (that is, the emission angles of the diffracted light from the diffraction grating surface are different).

  For this reason, the + 1st order diffracted light (or -1st order diffracted light) of each color of R, G, and B, which should be viewed as one display pixel, is emitted in different directions. When the image is viewed, there is a risk that the color blur is visible. Further, at a position far from the display device, only one color of the + 1st order diffracted light (or -1st order diffracted light) of each color of R, G, and B to be viewed as one display pixel can be viewed. In such a state, although a color image is displayed, there is a risk of being visually recognized as a red single color image, a green single color image, or a blue single color image.

  In this case, in the “display (display device)” configured to diffuse “each color light from the light diffraction unit” in the vertical direction by the “light diffusion unit”, the emission angle of each color light emitted from the “light diffraction unit” Even if the emission angle of each color light emitted from the “light reflecting portion” is somewhat different in the vertical direction (up and down direction), there is almost no influence on the visual recognition of the display image, but it is emitted from the “light diffraction portion”. When the emission angle of each color light differs in the horizontal direction (left-right direction), the above-described problem may occur. For this reason, when displaying a color image, it is necessary to configure the display so that each color light constituting each display pixel is emitted in substantially the same direction in the left-right direction. In addition, when displaying a color image on a “display (display device)” that does not include a “light diffusing unit”, each color light constituting each display pixel is substantially the same in both the horizontal and vertical directions. It is necessary to configure so that the light is emitted in the direction.

  Therefore, in the display device 1C (display 2C) shown in FIG. 30, as an example, the shape or material of each prism 20 constituting the optical path changing panel 12c is changed to the wavelength of the color light that should be refracted (the traveling direction should be changed). Accordingly, the prisms 40 constituting the light reflecting panel 14c are made different in shape or material according to the wavelength of the color light to be refracted (reflected), and each diffraction grating 30 is constituted. By making the formation pitch of each convex portion 31 different from each other according to the wavelength of the color light to be diffracted, the above-mentioned problems relating to color blur are overcome. In the display device 2C in the actual display device 1C, as an example, 81 types of “horizontal” different from each other in accordance with each direction from each parallax region for each viewpoint position in the left and right 81 directions on the front side of the display device 1C. Although it is configured so that an RGB color image of “× vertical = 1920 × 1080 pixels” can be visually recognized, each viewpoint in the left and right 81 directions is easy to understand the configuration of the display device 1C and the display device 2C. A configuration for visually recognizing one display pixel in the RGB color image for each parallax region for each position will be described.

  In this case, as an example, as illustrated in FIG. 31, the light source 3 </ b> C emits light L <b> 1 </ b> R (red color light), a light emitting unit 10 (light emitting units 10 </ b> A <b> 1 </ b> A <b> 1 to 10 </ b> I <b> 9 </ b> R: red subpixels). Sometimes referred to as “light emitting portion 10R”), light emitting portion 10 that emits light L1G (green color light) (light emitting portions 10A1G to 10I9G: green subpixels: hereinafter, “light emitting portion 10G” when not distinguished from each other) And a light emitting unit 10 that emits light L1B (blue color light) (light emitting units 10A1B to 10I9B: blue subpixels: hereinafter, also referred to as “light emitting unit 10B” when these are not distinguished) These are arranged in the vertical direction (vertical direction) in this order, and are arranged by one light emitting unit 10R, one light emitting unit 10G, and one light emitting unit 10B. One display pixel constituting an image (hereinafter, "color display pixels" and also referred to) is configured to emit respective colors light for viewing the. That is, in the light source 3C, one light emitting unit 10 (light emitting units 10R, 10G, and 10B) is provided for each subpixel of each color constituting one display pixel constituting one color image. Either) is provided.

  In FIG. 32 and FIGS. 32 to 34 referred to later, “R” is assigned to elements related to red (R), and “G” is assigned to elements related to green (G). In addition, elements related to blue (B) are indicated with a symbol “B”. In the following description, when it is necessary to distinguish between red (R), green (G), and blue (B), “R”, “G”, and “B” are added to the end of the reference numerals. . In this light source 3C, the light emitting portions 10R, 10G, and 10B that emit light of each color for visually recognizing one display pixel are arranged so as to be adjacent in the vertical direction (vertical direction). The position of the prism 20 for each light L1R, L1G, L1B in 12c, the position of each diffraction grating 30 for each light L1R, L1G, L1B on the diffraction grating panel 13c, and the position of each light emitting part 10R, 10G, 10B. By arranging according to the above, the light emitting portions 10R, 10G, and 10B that emit light of each color for visually recognizing one display pixel can be arranged at arbitrary positions (not shown).

  As shown in FIG. 32, for example, the optical path changing panel 12c changes the traveling direction of the light L1R emitted from each light emitting unit 10R in the light source 3C (refracts the light L1R) and emits it as light L2R. Prism 20 (prisms 20A1R to 20I9R: hereinafter, also referred to as “prism 20R” when they are not distinguished from each other), the traveling direction of the light L1G emitted from each light emitting unit 10G is changed (refracted by the light L1G). The prism 20 that emits as L2G (prisms 20A1G to 20I9G: hereinafter, also referred to as “prism 20G” when these are not distinguished) and the traveling direction of the light L1B emitted from each light emitting unit 10B are changed (light L1B is changed) Prism 20 (refracted 20A1B to 20I9B: refracted) and emitted as light L2B: “Prism 20B” is provided in this order in the vertical direction (vertical direction when not different), and one color display pixel is visually recognized by one prism 20R, one prism 20G, and one prism 20B. Therefore, the traveling direction of each color light is changed (an example of a configuration in which one prism as an optical path changing element is formed for each color light for displaying one display pixel). That is, in this optical path changing panel 12c, as an example, one prism 20 for each sub-pixel (9 × 9 × 3 = 243 sub-pixel) of each color that constitutes each display pixel constituting one color image. Is provided.

  In this case, in the optical path changing panel 12c, there is no physical boundary between the nine prisms 20R arranged in the horizontal direction, and the nine prisms 20R are integrally formed continuously as one prism. In addition, there is no physical boundary between the nine prisms 20G arranged in the horizontal direction, and the nine prisms 20G are integrally formed continuously as one prism and arranged in the horizontal direction. There is no physical boundary between the nine prisms 20B, and the nine prisms 20B are integrally formed continuously as one prism. That is, in this optical path changing panel 12c, nine prisms 200-1R to 200-9R that are long in the horizontal direction, nine prisms 200-1G to 200-9G that are long in the horizontal direction, and nine prisms 200-1B that are long in the horizontal direction. -200-9B are formed so as to be arranged in the vertical direction (vertical direction).

  Further, in this optical path changing panel 12c, in order to overcome the above-mentioned problems relating to the wavelength dependence of the light refraction phenomenon, the same optical material (for example, the refractive index for the light L1R is 1.514 and the refraction for the light L1G is used. Each prism 20R, 20G, 20B is formed using an optical material having a refractive index of 1.519 and a refractive index of 1.53 for the light L1B, and the shape of the prism 20R (prism angle) and the shape of the prism 20G. (Prism angle) and the shape of the prism 20B (prism angle) are different from each other. Specifically, the optical path changing panel 12c changes the traveling direction of the light L1G when the apex angle θp (see FIG. 3) of the prism 20R that changes the traveling direction of the light L1R is 34.8 °. Each prism 20R, 20G, prism 20R, 20G, prism 20G has an apex angle θp of 34.6 ° and an apex angle θp of the prism 20B that changes the traveling direction of the light L1B is 34.4 °. 20B is formed of a resin material having optical transparency.

  Thereby, in this optical path changing panel 12c, the emission angle of the light L2R from the prism 20R, the emission angle of the light L2G from the prism 20G, and the emission angle of the light L2B from the prism 20B are all 25.0 °. The emission angles of the light L2R, L2G, and L2B from the optical path changing panel 12c are equal to each other. In this case, since the emission angles of the light L2R, L2G, and L2B are equal to the above-described “αY”, the “αY” of the light L2R, L2G, and L2B is equal to each other (that is, each diffraction in the diffraction grating panel 13c). The incident angles of the light L2R, L2G, and L2B to the grating 30 are equal to each other). In addition, instead of the configuration of each prism 20 in the optical path changing panel 12c, an optical material that configures the prism 20R that changes the traveling direction of the light L1R, an optical material that configures the prism 20G that changes the traveling direction of the light L1G, And the optical materials constituting the prism 20B that changes the traveling direction of the light L1B are different (the optical materials are different from each other so that the refractive indexes with respect to the wavelengths of the respective color lights are equal to each other), so that the light L2R, L2G, A configuration in which “αY” of L2B is made equal to each other (incident angles of light L2R, L2G, and L2B to the diffraction gratings 30 in the diffraction grating panel 13c are made to be equal to each other) may be employed (not shown).

  The diffraction grating panel 13c diffracts the light L2G, as shown in FIG. 33, for diffracting the light L2R (diffraction gratings 30A1R to 30I9R: hereinafter, also referred to as “diffraction grating 30R” when not distinguished from each other). Diffraction grating 30 (diffractive gratings 30A1G to 30I9G: hereinafter, also referred to as “diffraction grating 30G” when not distinguished from each other), and diffraction grating 30 for diffracting the light L2B (diffraction gratings 30A1B to 30I9B: hereinafter, these Are also arranged in the vertical direction (vertical direction) in this order, and one color grating 30R, one diffraction grating 30G and one diffraction grating 30B provide one color. Each color light for visually recognizing a display pixel is configured to be diffracted (one display pixel Examples of configurations in which one diffraction grating is formed for each color light to display).

  As described above, in this specification, “one diffraction grating” is defined corresponding to “one light emitting portion” among optical elements configured to be able to diffract incident light. Means the site. Therefore, in this diffraction grating panel 13c, one diffraction grating 30 (diffraction gratings 30R, 30G, 30B) corresponding to one light emitting part 10 (any of the light emitting parts 10R, 10G, 10B) in the light source 3C described above. 1) for each sub-pixel of each color constituting one of the display pixels constituting one color image (any one of the diffraction gratings 30R, 30G, 30B). Is stipulated.

  Further, in the display device 2C of this example, in order to emit each color light for visually recognizing one color display pixel from the diffusion plate 15 in the same direction in the left-right direction, the diffraction grating surface F3 with respect to the panel surface F5 of the diffusion plate 15 Are diffracted with respect to each color light (light L2) for displaying one color display pixel in a state where the inclinations are equal to each other (in this example, each diffraction grating surface F3 is parallel to the panel surface F5). Diffraction for diffraction gratings 30R, 30G, and 30B that diffracts light L2 having a longer wavelength λ than the grating formation pitch d (formation pitch d of projections 31) in diffraction grating 30 that diffracts light L2 having a shorter wavelength λ. The diffraction grating panel 13c is formed so that the grating formation pitch d (formation pitch d of the protrusions 31) in the grating 30 is larger.

  Specifically, with respect to the grating formation pitch d (projection 31 formation pitch d), the diffraction grating 30G that diffracts the light L2G having a longer wavelength λ than the light L2B is larger than the diffraction grating 30B, and The diffraction gratings 30R, 30G, and 30B are formed so that the diffraction grating 30R that diffracts the light L2R having a longer wavelength λ than the light L2G is larger than the diffraction grating 30G. More specifically, in the diffraction grating panel 13c, the grating in the diffraction grating 30R that diffracts the light L2R having the “wavelength λ = 633 nm” has the “forming pitch d = 633 nm” and the light L2G having the “wavelength λ = 532 nm”. The grating in the diffraction grating 30G that diffracts is “formation pitch d = 532 nm”, and the grating in the diffraction grating 30B that diffracts the light L2B of “wavelength λ = 472 nm” is “formation pitch d = 472 nm” ( Example of “configuration in which the pitch of the grating in the grating is equal to the wavelength λ of the light to be diffracted”). By adopting such a configuration, the diffraction grating panel 13c can be easily designed.

  As shown in FIG. 34, the light reflecting panel 14c includes, as an example, prisms 40A1R to 40I9R (hereinafter also referred to as “prism 40R” when not distinguished from each other) and prisms 40A1G to 40I9G (hereinafter referred to as “prism when not distinguished from each other”. 40G ") and prisms 40A1B to 40I9B (hereinafter also referred to as" prism 40B "when they are not distinguished from each other) are arranged in this order in the vertical direction (vertical direction), and one prism 40R, one prism 40G and one prism 40B are configured to change the traveling direction of each color light for visually recognizing one color display pixel (one reflection for each color light for displaying one display pixel). Example of configuration in which prism as element is formed). That is, in this light reflecting panel 14c, as an example, one prism 40 per one of the subpixels (9 × 9 × 3 = 243 subpixels) of each color constituting each display pixel constituting one color image. Is provided.

  In this case, the prisms 40R, 40G, and 40B emit the + 1st order diffracted light L3b (or the −1st order diffracted light L3c) of each color emitted from the diffraction grating 30R of the diffraction grating panel 13c and incident from the interface F4a to the diffusion plate 15 side. The 0th-order diffracted light L3a of each color emitted from the diffraction gratings 30R, 30G, and 30B and incident from the interface F4a is reflected at the interface F4b (for example, the first incident on the interface F4b). In some cases, it is configured to suppress the transmission of the 0th-order diffracted light L3a of each color to the diffuser plate 15 side in the same manner as the light-reflecting panel 14 (prism 40) for the monochromatic image described above. Yes. In the following description, the red + 1st order diffracted light L3b (or -1st order diffracted light L3c) and the red 0th order diffracted light L3a are also collectively referred to as “light L3R”, and the green + 1st order diffracted light L3b (or -1st order diffracted light L3c) and green 0th order diffracted light L3a are collectively referred to as "light L3G", and blue + 1st order diffracted light L3b (or -1st order diffracted light L3c) and blue 0th order diffracted light L3a are collectively referred to. Also referred to as “light L3B”.

  In the light reflecting panel 14c, there is no physical boundary between the nine prisms 40R arranged in the horizontal direction, and the nine prisms 40R are integrally formed continuously as one prism. In addition, there is no physical boundary between the nine prisms 40G arranged in the horizontal direction, and these nine prisms 40G are integrally formed continuously as one prism, and are arranged in the horizontal direction 9 There is no physical boundary between the prisms 40B, and the nine prisms 40B are integrally formed continuously as one prism. That is, in this light reflection panel 14c, nine prisms 400-1R to 400-9R that are long in the horizontal direction, nine prisms 400-1G to 400-9G that are long in the horizontal direction, and nine prisms 400-1B that are long in the horizontal direction. ˜400-9B are arranged in the vertical direction (vertical direction). In order to facilitate understanding of the reflection of the 0th-order diffracted light L3a by the light reflecting panel 14c and the transmission of the + 1st-order diffracted light L3b (or the −1st-order diffracted light L3c), as an example, θa of the prisms 40R, 40G, and 40B. Will be described as an example (a configuration in which the interface F4a is parallel to the panel surface F5 and the like like the prism 40 in the light reflection panel 14a described above) (refractive indexes and angles θa and θb of the prisms 40R, 40G, and 40B). Will be described in detail later).

In this display device 1C (display device 2C), the light L2 emitted from the light source 3C and refracted by the optical path changing panel 12c is diffracted by each diffraction grating 30 and distributed in the left and right 81 directions, and left and right by each diffraction grating 30. Of the light L3 distributed in the direction, the first-order diffracted light L3b (or-) that reflects the 0th-order diffracted light L3a at the interface F4b of each prism 40 (400) of the light reflecting panel 14c and transmits the light reflecting panel 14c. 1st-order diffracted light L3c) is emitted from the interface F4b and diffused in the vertical direction (vertical direction) by the diffusion plate 15, thereby expanding the viewing area in the vertical direction (vertical direction) for each parallax region in the left and right 81 directions. (Different parallax images are visible in the left-right direction, and the same parallax image is visible in the vertical direction. Configured to display) is employed to. Specific examples are shown in FIGS. 35 to 37 show various parameters related to only five of the 81 color display pixels A1 to I9, that is, the color display pixels A1, C3, E5, G7, and I9. Further, in each example shown in FIGS. 35 to 37, the same configuration is adopted for the other constituent elements except that the shapes (angle θb) of the respective prisms 40R, 40G, and 40B constituting the light reflecting panel 14c are different. Has been. In addition, “βx”, “βy”, “βX”, “β ₁ Y”, and “β ₂ Y” in FIGS. 35 to 37 indicate “the emission angle of the + 1st-order diffracted light L3b”.

  Specifically, in the light reflecting panel 14c of the display device 1C (display device 2C) shown in FIG. 35, the same optical material (for example, the same optical material as that constituting the prisms 20R, 20G, and 20B is used. Each of the prisms 40R, 40G, and 40B is formed using an optical material having a refractive index of 1.514 for L3R, a refractive index of 1.519 for light L3G, and a refractive index of 1.523 for light L3B. The shapes (prism angles) of the prisms 40R, 40G, and 40B are different from each other. Specifically, in the light reflecting panel 14c, the angles θa and θb of the prism 40R are 0.0 ° and 28.0 °, respectively, and the angles θa and θb of the prism 40G are 0.0 ° and The prisms 40R, 40G, and 40B are formed of a resin material having optical transparency so that the angles θa and θb of the prism 40B are 0.0 ° and 27.6 °, respectively, at 27.8 °. . Hereinafter, the light corresponding to the pixel E5 will be described.

  In this case, the 0th-order diffracted light L3a emitted from the diffraction grating panel 13c is transmitted through each diffraction grating 30 in the diffraction grating panel 13, and the incident angles of the light L2R, L2G, and L2B with respect to the diffraction grating surface F3 of each diffraction grating 30 Is emitted from the diffraction grating panel 13 at an angle equal to. Therefore, in the light reflecting panel 14c having the prisms 40R, 40G, and 40B in which the angles θa and θb of the interfaces F4a and F4b are formed as described above, the 0th-order diffracted light L3a incident on the light reflecting panel 14 is red. The 0th-order diffracted light L3a is refracted at the interface F4a of the prism 40R and the angle (θ2) between the normal line L14a of the interface F4a is 16.2 °, and the green 0th-order diffracted light L3a is the interface F4a of the prism 40G. And the angle (θ2) between the normal L14a and the normal L14a is 16.2 °, and the blue zero-order diffracted light L3a is refracted at the interface F4a of the prism 40B and the angle (θ2) between the normal L14a and the normal L14a. 16.1 °. As a result, the incident angle (θ3) with respect to the interface F4b of the prism 40R becomes 44.2 ° for the red 0th-order diffracted light L3a, and the incident angle (θ3) with respect to the interface F4b of the prism 40G for the green 0th-order diffracted light L3a. Is 44.0 °, and for the blue zero-order diffracted light L3a, the incident angle (θ3) with respect to the interface F4b of the prism 40B is 43.7 °.

  Here, according to the conditional expression of total reflection described above, when the red 0th-order diffracted light L3a is incident on the interface F4b of the prism 40R at an incident angle of 41.4 ° or more, the 0th-order diffracted light L3a is With respect to the green 0th-order diffracted light L3a, the 0th-order diffracted light L3a is totally reflected when incident on the interface F4b of the prism 40G at an incident angle of 41.2 ° or more, and the blue 0th-order diffracted light L3a is reflected. With respect to, the zero-order diffracted light L3a is totally reflected when it is incident on the interface F4b of the prism 40B at an incident angle of 41.1 ° or more. Therefore, in the light reflecting panel 14c in which the incident angles of the respective 0th-order diffracted lights L3a with respect to the respective interfaces F4b of the prisms 40R, 40G, and 40B are the above angles, the 0th-order diffracted lights L3a emitted from the diffraction grating panel 13 are emitted. Is totally reflected at the interface F4b of each prism 40 (400) and enters the interface F4a, further totally reflected at the interface F4a, and finally emitted from the lower end face of the light reflecting panel 14c.

  In the “light reflecting portion” that satisfies the condition that the angles θa and θb of the interfaces F4a and F4b of the “reflecting element” are “θa ≦ θb”, the 0th-order diffracted light L3a is reflected at the interface F4b for the first time. When totally reflected, the 0th-order diffracted light L3a is totally reflected even after the second reflection at the interface F4b, or the second-order 0th-order diffracted light L3a is not reflected at the interface F4b (reflected at the interface F4a). The 0th-order diffracted light L3a is not emitted to the interface F4b and is emitted from the vertical end portion (or the horizontal end portion) of the “light reflecting portion” to the outside of the “light reflecting portion”.

  As a result, as shown in FIG. 38, in this light reflecting panel 14c, the transmittance of each of the red, green and blue 0th order diffracted light L3a is 0%, and the 0th order diffracted light L3a of each color toward the diffusion plate 15 side. The emission is suppressed. In FIGS. 39 and 40 to be referred to later, the transmittance of one of the 81 color display pixels A1 to I9 for the color display pixel E5 is illustrated. In this case, unlike the example shown in FIG. 35, for example, even when the light L3a reflected at the interface F4b is not totally reflected at the interface F4a when entering the interface F4a, the light L3a is transmitted from the interface F4a. Since the light is emitted toward the diffraction grating panel 13c, transmission of the 0th-order diffracted light L3a from the diffraction grating panel 13c to the diffusion plate 15 side is sufficiently suppressed as a result.

On the other hand, the + _{1st order} diffracted light L3b emitted from the diffraction grating panel 13c has an emission angle (β ₁ Y) from the diffraction grating panel 13 formed as described above of 35.3 °. Therefore, in the light reflecting panel 14c having the prisms 40R, 40G, and 40B in which the angles θa and θb of the interfaces F4a and F4b are formed as described above, the + 1st order diffracted light L3b incident on the light reflecting panel 14 is red. The + 1st order diffracted light L3b is refracted at the interface F4a of the prism 40R and the angle (θ2) between the normal line L14a of the interface F4a is 22.4 °, and the green + 1st order diffracted light L3b is the interface F4a of the prism 40G. And the angle (θ2) between the normal L14a and the normal L14a is 22.3 °, and the blue first-order diffracted light L3b is refracted at the interface F4a of the prism 40B and the angle (θ2) with the normal L14a is 22.3 °.

As a result, for the red + 1st order diffracted light L3b, the incident angle (θ3) with respect to the interface F4b of the prism 40R is −5.6 °, and for the green + 1st order diffracted light L3b, the incident angle with respect to the interface F4b of the prism 40G is ( θ3) is −5.5 °, and the incident angle (θ3) with respect to the interface F4b of the prism 40B is −5.3 ° for the blue first-order diffracted light L3b. Accordingly, in this light reflecting panel 14c, the + 1st order diffracted light L3b of each color (transmitted through the light reflecting panel 14c) is emitted from the light reflecting panel 14c at an emission angle (β ₂ Y) = 19.5 °. The In this case, as shown in FIG. 38, in the light reflecting panel 14c, the transmittance of each of the red, green, and blue + 1st order diffracted lights L3b exceeds 91%. As described above, in the light reflection panel 14c of the display device 1C (display device 2C) shown in FIG. 35, at least a part of the 0th-order diffracted light L3a is reflected by each prism 40 (400), whereby each prism 40 (400) Since the transmittance of the 0th-order diffracted light L3a in each prism 40 (400) is smaller than the transmittance of the + 1st-order diffracted light L3b, the 0th-order diffracted light L3a of each color emitted from the diffraction grating panel 13c. A ghost image due to the absence of a ghost image or a clear image in which the ghost image is difficult to be visually recognized is visually recognized.

  On the other hand, in the light reflection panel 14c of the display device 1C (display device 2C) shown in FIGS. 36 and 37, the same optical material (as an example, the same material as the optical material constituting the prisms 20R, 20G, and 20B) is used. The prisms 40R, 40G, and 40B are formed using the prisms 40R, 40G, and 40B, and the shapes (prism angles) of the prisms 40R, 40G, and 40B are formed to be equal. Specifically, each of the prisms 40R, 40G, and 40B of the light reflecting panel 14c in the example shown in FIG. 36 has light transmittance so that the angles θa and θb are 0.0 ° and 30.0 °, respectively. 37, each of the prisms 40R, 40G, and 40B of the light reflecting panel 14c in the example shown in FIG. 37 transmits light so that the angles θa and θb are 0.0 ° and 24.9 °, respectively. It is made of a resin material having properties. Hereinafter, the light corresponding to the pixel E5 will be described.

  In this case, in the light reflecting panel 14c of the example shown in FIG. 36, the red zero-order diffracted light L3a is refracted at the interface F4a of the prism 40R and the angle (θ2) between the normal L14a of the interface F4a is 16.2. With respect to the green zero-order diffracted light L3a, the angle (θ2) formed by refraction at the interface F4a of the prism 40G and the normal L14a is 16.2 °, and for the blue zero-order diffracted light L3a, the prism 40B The angle (θ2) formed by refraction at the interface F4a and the normal L14a is 16.1 °. Thereby, the incident angle (θ3) with respect to the interface F4b of the prism 40R is 46.2 ° for the red 0th-order diffracted light L3a, and the incident angle (θ3) with respect to the interface F4b of the prism 40G is for the green 0th-order diffracted light L3a. Is 46.2 °, and for the blue zero-order diffracted light L3a, the incident angle (θ3) with respect to the interface F4b of the prism 40B is 46.1 °.

  In this light reflecting panel 14c in which the incident angle of each 0th-order diffracted light L3a with respect to each interface F4b of the prisms 40R, 40G, and 40B is the above angle, the 0th-order diffracted light L3a emitted from the diffraction grating panel 13 is each The prism 40 (400) is totally reflected at the interface F4b and enters the interface F4a. Further, the prism 40 (400) is totally reflected at the interface F4a, and finally is emitted from the lower end face of the light reflecting panel 14c. As a result, as shown in FIG. 39, in this light reflecting panel 14c, the transmittances of the red, green, and blue 0th order diffracted lights L3a are each 0%, and the respective 0th order diffracted lights L3a are emitted to the diffusion plate 15 side. Is suppressed.

On the other hand, the + _{1st order} diffracted light L3b emitted from the diffraction grating panel 13c has an emission angle (β ₁ Y) from the diffraction grating panel 13 formed as described above of 35.3 °. Therefore, in the light reflecting panel 14c having the prisms 40R, 40G, and 40B in which the angles θa and θb of the interfaces F4a and F4b are formed as described above, the + 1st order diffracted light L3b incident on the light reflecting panel 14 is red. The + 1st order diffracted light L3b is refracted at the interface F4a of the prism 40R and the angle (θ2) between the normal line L14a of the interface F4a is 22.4 °, and the green + 1st order diffracted light L3b is the interface F4a of the prism 40G. And the angle (θ2) between the normal L14a and the normal L14a is 22.3 °, and the blue first-order diffracted light L3b is refracted at the interface F4a of the prism 40B and the angle (θ2) with the normal L14a is 22.3 °.

As a result, for the red + 1st order diffracted light L3b, the incident angle (θ3) with respect to the interface F4b of the prism 40R becomes −7.6 °, and for the green + 1st order diffracted light L3b, the incident angle (θ3) with respect to the interface F4b of the prism 40G. ) Is −7.7 °, and for the blue first-order diffracted light L3b, the incident angle (θ3) with respect to the interface F4b of the prism 40B is −7.7 °. Therefore, in this light reflection panel 14c, the + 1st order diffracted light L3b of each color is transmitted through the light reflection panel 14c, and β ₂ Y is reflected at the emission angles of 18.5 °, 18.3 °, and 18.2 °, respectively. The light is emitted from the panel 14c. In this case, as shown in FIG. 39, in the light reflecting panel 14c, the transmittances of the red, green, and blue + first-order diffracted lights L3b each exceed 91%.

As described above, in the light reflecting panel 14c of the display device 1C (display 2C) shown in FIG. 36, at least a part of the 0th-order diffracted light L3a is supplied to each of the light reflecting panels 14c shown in FIG. By reflecting on the prism 40 (400), the transmittance of the 0th-order diffracted light L3a in each prism 40 (400) is smaller than the transmittance of the + 1st-order diffracted light L3b in each prism 40 (400). Therefore, a ghost image due to the 0th-order diffracted light L3a of each color emitted from the diffraction grating panel 13c does not exist, or a clear image in which the ghost image is difficult to be visually recognized is visually recognized. In this case, in the light reflection panel 14c of the example shown in FIG. 36, the emission angles (β ₂ Y) of the + 1st order diffracted light L3b of each color from the light reflection panel 14c are slightly different, but +1 transmitted through the light reflection panel 14c. In the display device 1C in which the next-order diffracted light L3b is diffused in the vertical direction of the display 2C by the diffusion plate 15, this difference in the emission angle (β ₂ Y) of the + 1st-order diffracted light L3b for each color is not a problem. .

  In the light reflecting panel 14c of the example shown in FIG. 37, the red 0th-order diffracted light L3a is refracted at the interface F4a of the prism 40R and the angle (θ2) between the normal line L14a of the interface F4a is 16.2 °. For the green zero-order diffracted light L3a, the angle (θ2) formed by refraction at the interface F4a of the prism 40G and the normal L14a is 16.2 °, and for the blue zero-order diffracted light L3a, the interface of the prism 40B The angle (θ2) formed by refraction at F4a and the normal L14a is 16.1 °. Thereby, the incident angle (θ3) with respect to the interface F4b of the prism 40R becomes 41.1 ° for the red 0th-order diffracted light L3a, and the incident angle (θ3) with respect to the interface F4b of the prism 40G for the green 0th-order diffracted light L3a. Is 41.1 °, and for the blue zero-order diffracted light L3a, the incident angle (θ3) with respect to the interface F4b of the prism 40B is 41.0 °.

  In the light reflection panel 14c in which the incident angles of the respective 0th-order diffracted lights L3a with respect to the respective interfaces F4b of the prisms 40R, 40G, and 40B are the above angles, one of the 0th-order diffracted lights L3a emitted from the diffraction grating panel 13 is provided. Is emitted from the interface F4b of each prism 40 (400) to the diffusion plate 15 side. However, as shown in FIG. 40, the transmittances of the red, green, and blue 0th-order diffracted lights L3a are each less than 40%, and the emission of the 0th-order diffracted lights L3a of the respective colors to the diffusion plate 15 side is sufficiently suppressed. Has been.

On the other hand, the + _{1st order} diffracted light L3b emitted from the diffraction grating panel 13c has an emission angle (β ₁ Y) from the diffraction grating panel 13 formed as described above of 35.3 °. Therefore, in the light reflecting panel 14c having the prisms 40R, 40G, and 40B in which the angles θa and θb of the interfaces F4a and F4b are formed as described above, the + 1st order diffracted light L3b incident on the light reflecting panel 14 is red. The + 1st order diffracted light L3b is refracted at the interface F4a of the prism 40R and the angle (θ2) between the normal line L14a of the interface F4a is 22.4 °, and the green + 1st order diffracted light L3b is the interface F4a of the prism 40G. And the angle (θ2) between the normal L14a and the normal L14a is 22.3 °, and the blue first-order diffracted light L3b is refracted at the interface F4a of the prism 40B and the angle (θ2) with the normal L14a is 22.3 °.

Accordingly, the incident angle (θ3) with respect to the interface F4b of the prism 40R becomes −2.5 ° for the red + 1st order diffracted light L3b, and the incident angle (θ3) with respect to the interface F4b of the prism 40G for the green + 1st order diffracted light L3b. ) Is −2.6 °, and the incident angle (θ3) with respect to the interface F4b of the prism 40B is −2.6 ° for the blue first-order diffracted light L3b. Therefore, in this light reflection panel 14c, the + 1st order diffracted light L3b of each color is transmitted through the light reflection panel 14c, and β ₂ Y is reflected at the emission angles of 21.1 °, 21.0 °, and 20.9 °, respectively. The light is emitted from the panel 14c. In this case, as shown in FIG. 40, in the light reflecting panel 14c, the transmittances of the red, green, and blue + first-order diffracted lights L3b each exceed 91%.

  As described above, in the light reflecting panel 14c of the display device 1C (display device 2C) shown in FIG. 37, at least a part of the 0th-order diffracted light L3a is reflected at each prism 40 (400), so that each prism 40 (400) Since the transmittance of the 0th-order diffracted light L3a in each prism 40 (400) is smaller than the transmittance of the + 1st-order diffracted light L3b, the 0th-order diffracted light L3a of each color emitted from the diffraction grating panel 13c. A clear image in which a ghost image caused by the above is difficult to be visually recognized will be visually recognized.

  Further, in these display devices 1C (display 2C), as shown in FIGS. 35 to 37, light L3 emitted from the diffraction grating panel 13c (each diffraction grating surface F3) in order to make one color display pixel visible. The angle components (βX described above) in the left-right direction of the display 2C at the emission angle of light (L3R, L3G, L3B: see FIG. 30) are equal to each other. Therefore, in the display device 1C (display device 2C), the + 1st-order diffracted light L3b among these lights L3R, L3G, and L3B is diffused in the vertical direction by the diffusion plate 15 and is displayed as the light L5R, L5G, and L5B. The light is emitted in the same direction in the left-right direction toward the front of (display 2C). As shown in both figures, the diffraction grating panel 13c in the display device 1C (display 2C) satisfies the condition “| (−λ−d · sin (αy)) / d | ≧ 1”. Has been. In the diffraction grating panel 13c that satisfies such conditions, the −1st order diffracted light L3c does not exit from the diffraction grating panel 13c, and therefore, the −1st order diffracted light L3c is emitted from the diffraction grating panel 13c (incident on the diffusion plate 15). Thus, a situation where the stereoscopic image (color image) image is blurred is avoided.

  Thus, in the display device 2 (2C), the diffraction grating panel 13 (13c) that diffracts the light from the light source 3 (3C) (in this example, the light L2 whose optical path has been changed by the optical path changing panel 12 (12c)). The prism 40 (400) in which the light L3 can be made incident by an optical material capable of transmitting the diffracted light (light L3: 0th-order diffracted light L3a, + 1st-order diffracted light L3b (or -1st-order diffracted light L3c)). ), And either the + 1st order diffracted light L3b or the −1st order diffracted light L3c as the light L3 is transmitted through the prism 40 (400) and emitted from the prism 40 (400). Thus, a plurality of images are displayed so that different images can be visually recognized from each viewpoint position that is opposite to the display device 2 (2C) and is different in the left-right direction of the display device 2 (2C). By reflecting the 0th-order diffracted light L3a at the prism 40 (400), the prism 40 (400) has 0 as compared with the transmittance of the + 1st-order diffracted light L3b (or -1st-order diffracted light L3c). The light reflecting panel 14 (14c) is configured so that the transmittance of the next diffracted light L3a is smaller. In the display 2 (2C), the light reflection panel 14 (14c) is configured such that the 0th-order diffracted light L3a is totally reflected at the interface F4b of the prism 40 (400). Further, the display device 1 (1C) controls the lighting of the display device 2 (2C), the light source 3 (3C), and the light source 3 (3C) to display an image on the display device 2 (2C). And is configured.

  Therefore, according to the display device 2 (2C) and the display device 1 (1C) provided with the display device 2 (2C), the light reflection panel 14 sufficiently reflects the 0th-order diffracted light L3a to the diffusion plate 15 side. In order to suppress the emission of the 0th-order diffracted light L3a, a situation where a so-called ghost image is displayed due to the presence of the 0th-order diffracted light L3a emitted from the diffraction grating panel 13 (13c) is suppressed, and a clear image is displayed. Can be displayed.

  Furthermore, according to the display 2C (example shown in FIG. 35), the prism 40 (400) is provided corresponding to each color light for displaying one display pixel, and one display pixel is displayed. By forming at least one of the optical material and shape of the prism 40 (400) corresponding to each color light (in this example, the angle θb: shape of the interface F4b) to be different from each other, the light reflecting panel 14c is configured. Not only can the display of a ghost image due to the presence of the 0th-order diffracted light L3a be suppressed, but also the emission of the + 1st-order diffracted light L3b (or -1st-order diffracted light L3c) of each color emitted from the light reflecting panel 14c. Since the angles can be aligned to the same angle, for example, even in a configuration that does not include the diffusion plate 15, it is possible to avoid a situation in which color images are blurred in the vertical direction. It is possible.

  Further, according to the display 2C (examples shown in FIGS. 36 and 37), the prism 40 (400) is provided corresponding to each color light for displaying one display pixel and one display pixel is displayed. The light reflection panel 14c is designed and manufactured by forming the light reflection panel 14c by forming the prisms 40 (400) corresponding to the respective color lights to be the same optical material and having the same shape. As a result of being easily performed, the manufacturing cost of the display 2C can be sufficiently reduced.

The configurations of the “display device” and the “display device” are not limited to the configurations of the display device 2 (2C) and the display device 1 (1C). For example, the display 2 (2C) including the optical path changing panel 12 (12c) having the prism 20 (200) for changing the traveling direction of the light L1 from the light source 3 (3C) has been described as an example. Instead of the optical path changing panel 12 (12c), an “optical path changing element” “an element that changes the traveling direction of light by an electro-optic effect (EO effect): hereinafter also referred to as an“ EO effect element ”” is provided. It is also possible to adopt a configuration in which an optical path changing panel (not shown) configured as described above is provided as an “optical path changing unit”. In this case, as an “EO effect element”, for example, a KTN crystal (a crystal of potassium tantalate niobate (KTa _1-x Nb _x O ₃ )) and an upper surface of the KTN crystal are disposed. It can be composed of an electrode (anode) and an electrode (cathode) disposed on the lower surface of the KTN crystal. This KTN crystal is an oxide having a perovskite crystal structure, and has an “electro-optic effect (EO effect)” in which the refractive index changes when a voltage is applied between the end faces. It has been known. Therefore, by applying a voltage between both electrodes according to the angle at which the light L1 from the light source 3 (3C) should be refracted, the desired angle can be obtained in the same manner as when the light L1 is refracted by the prism 20 (200). Thus, the light L2 can be emitted from the “EO effect element” and incident on the diffraction grating 30 of the diffraction grating panel 13 (13c) obliquely.

  Further, the light L1 from the light source 3 (3C) is refracted by the “optical path changing unit” and is incident obliquely on the diffraction grating surface F3 of the diffraction grating 30 of the diffraction grating panel 13 (13c), thereby obtaining the + 1st order diffracted light. The configuration for reducing the light amount of the −1st order diffracted light L3c (or the + 1st order diffracted light L3b) with respect to L3b (or the −1st order diffracted light L3c) has been described. However, the “optical path changing unit” is an essential configuration for the “display”. It is not an element. For example, a configuration in which the light L1 from the light source 3 (3C) is directly incident on the “diffraction grating” of the “light diffraction unit” can be employed. In this case, in the display device 2 (2C), the diffraction grating panel 13 so that the diffraction grating surface F3 of the diffraction grating 30 is parallel to the panel surface F5 of the diffusion plate 15, the panel surface F1 of the light source 3 (3C), and the like. (13c) is configured, but by tilting the diffraction grating surface F3 of the diffraction grating 30 with respect to the panel surface F5 of the diffusion plate 15, the panel surface F1 of the light source 3 (3C), etc., the light source 3 (3C) Can be incident obliquely on the diffraction grating surface F3 (not shown). Even when such a configuration is adopted, the light amount of the −1st order diffracted light L3c (or the + 1st order diffracted light L3b) with respect to the + 1st order diffracted light L3b (or −1st order diffracted light L3c) can be reduced. Similarly to 2 (2C), the utilization efficiency of the light L1 from the light source 3 (3C) can be sufficiently increased.

  In addition, for example, a concavo-convex pattern (grating pattern) in which a plurality of convex portions 31 that are linear in plan view and a plurality of concave portions 32 that are linear in plan view are formed at a predetermined formation pitch is used as a diffraction grating 30. Although the example provided with the diffraction grating panel 13 (13c) configured to function as the “diffraction grating” is not limited to this, as an example, the diffraction grating 30a in the diffraction grating panel 13d shown in FIGS. In this way, a concavo-convex pattern (lattice pattern) composed of a plurality of convex portions in a planar view that do not intersect with each other and a plurality of concave portions in a curved shape in a plan view that do not intersect with each other is formed as “diffraction” A configuration that functions as a “lattice” can be employed. In both figures, as an example, the center of the convex portion in the width direction is shown by a solid line (curve).

  In this case, as described above, in this specification, “one diffraction grating” is defined corresponding to “one light emitting portion” among optical elements configured to be able to diffract incident light. It means the part which was done. Therefore, in a diffraction grating panel in which convex portions having a curved shape in plan view and concave portions having a curved shape in plan view are formed as a grating pattern, one light emitting portion in the light source (one light emitting portion 10 in the light source 3 described above, or An element corresponding to one of the light emitting portions 10R, 10G, and 10B in the light source 3C described above: In other words, in a light source for displaying a monochrome image, one of the display pixels constituting one monochrome image. In the light source for displaying a color image, each sub-pixel corresponding to each color light in one of the display pixels constituting one color image. One diffraction grating 30a (a rectangular region separated by a rough broken line in both drawings) is defined corresponding to one of the optical elements that emits light corresponding to one of them.

  Note that, in the diffraction grating 30a in which convex portions having a curved shape in plan view and concave portions having a curved shape in plan view are formed as a grating pattern, as shown in FIG. 42, as an example, the convex portion as a grating is one end portion of the diffraction grating 30a ( For example, a solid line Lc connecting the intersection point P1 intersecting with the left end portion in the figure and the intersection point P2 where the convex portion intersects with the other end portion of the diffraction grating 30a (in this example, the right end portion in the figure) is represented by a grid line. And Also in the diffraction grating panel 13d having such a configuration, the above-described diffraction grating panel 13 is defined by defining the formation pitch d of each convex portion, the perist rotation angle (rotation angle of the grating line), and the like for each diffraction grating 30a. Similarly to (13c), the light L2 (L2R, L2G, L2B) from the optical path changing panel 12 (12c) can be diffracted and emitted in an arbitrary direction.

  Further, for example, a concavo-convex pattern in which a plurality of convex portions 31 and a plurality of concave portions 32 are formed at a predetermined formation pitch is formed for each formation region of each diffraction grating 30, and this concavo-convex pattern functions as the diffraction grating 30. Display 2 (2C) and display device having diffraction grating panel 13 (13c) configured to diffract light L2 (L2R, L2G, L2B) from optical path changing panel 12 (12c) in a predetermined direction 1 (1C) has been described as an example, but light from the optical path changing panel 12 (12c) is replaced with any of the diffraction grating panels 13e to 13g shown in FIGS. 43 to 45 instead of the diffraction grating panel 13 (13c). L2 (L2R, L2G, L2B) can also be configured to diffract in a predetermined direction.

  In this case, the diffraction grating panels 13e to 13g have a plurality of convex portions 31a and a plurality of concave portions (slits) instead of the grating pattern (concave / convex pattern) including the convex portions 31 and the concave portions 32 in the diffraction grating panel 13 (13c) described above. ) 32a is formed, and this grating pattern functions as the diffraction grating 30b to diffract the light L2 (L2R, L2G, L2B) from the optical path changing panel 12 (12c) in a predetermined direction. It is configured as follows. In addition, in these diffraction grating panels 13e-13g, about the element similar to each element of the diffraction grating panel 13 (13c) mentioned above, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  In this case, as shown in FIGS. 43 and 44, in the diffraction grating 30b of the diffraction grating panels 13e and 13f, the extending direction of the convex portion 31a (the direction of the solid line La in the figure) is relative to the diffraction grating surface F3. The direction intersects perpendicularly (direction parallel to the normal line of the diffraction grating surface F3: δy = 0 °). Accordingly, the diffraction grating 30b of the diffraction grating panels 13e and 13g functions in the same manner as the diffraction grating 30 of the diffraction grating panel 13 (13c) with δy = 0 °. On the other hand, as shown in FIG. 45, in the diffraction grating 30b of the diffraction grating panel 13g, the direction in which the projecting portion 31a extends (the direction of the solid line La in the figure) obliquely intersects the diffraction grating surface F3. (Orientation non-parallel to the normal line of the diffraction grating surface F3: δy ≠ 0 °). Accordingly, the diffraction grating 30b of the diffraction grating panel 13g functions in the same manner as the diffraction grating of the diffraction grating panel (for example, the diffraction grating panel 13 shown in FIG. 24) with δy ≠ 0 °.

  Further, the light L2 (L2R, L2G, L2B) from the optical path changing panel 12 (12c) is diffracted in a predetermined direction by any of the diffraction grating panels 13h to 13j shown in FIGS. You can also. In this case, the diffraction grating panels 13h to 13j are replaced with a plurality of high refractive index materials formed of a high refractive index material in place of the grating pattern (concave / convex pattern) including the convex portions 31 and the concave portions 32 in the diffraction grating panel 13 (13c) described above. A grating pattern composed of a refractive index portion 35 and a plurality of low refractive index portions 36 formed of a low refractive index material is formed, and this grating pattern functions as a diffraction grating 30c, from the optical path changing panel 12 (12c). The light L2 (L2R, L2G, L2B) is diffracted in a predetermined direction. In this case, in the present specification, the high refractive index portions 35 in the diffraction gratings 30c of the diffraction grating panels 13h to 13j are the same components as the convex portions 31 of the diffraction grating 30 and the convex portions 31a of the diffraction grating 30b described above. To do. That is, the “extending direction of the convex portion” in the diffraction grating 30c of the diffraction grating panels 13h to 13j means the extending direction of the high refractive index portion 35 (the direction of the solid line La in each drawing). Even when such a configuration is adopted, it functions as an “optical diffraction section” similar to the diffraction grating panels 13 (13c), 13a, 13b, and 13e to 13f described above.

  Further, instead of the diffraction grating panels 13 and 13a to 13j, an “optical diffraction section” having a blazed diffraction grating such as the diffraction grating panel 13k shown in FIG. 46 may be employed. In this case, in the blazed diffraction grating, the light L1 from the light source 3 (3C) is refracted by the respective prisms 20 (200) of the optical path changing panel 12 (12c), whereby the light is applied to the diffraction grating surface F3 of the diffraction grating 30. The structure in which L2 is incident obliquely, or the light L1 from the light source 3 (3C) is inclined with respect to the diffraction grating surface F3 by tilting the diffraction grating surface F3 of the diffraction grating 30 with respect to the panel surface F1 of the light source 3 (3C). Similar to the configuration in which the light is incident obliquely, the light amount of the −1st order diffracted light L3c (or + 1st order diffracted light L3b) with respect to the + 1st order diffracted light L3b (or −1st order diffracted light L3c) emitted from the diffraction grating is sufficiently reduced. Can be made. In addition, the “optical path changing unit” for refracting the light L1 from the light source 3 (3C) is not necessary, and the diffraction grating surface F3 of the diffraction grating 30 is set to the panel surface F1 of the light source 3 (3C). There is no need to tilt. Therefore, by adopting this blazed diffraction grating, it is possible to manufacture a display device with sufficiently increased utilization efficiency of the light L1 from the light source 3 (3C) at a low cost.

  Further, the configuration including the diffraction grating panels 13 and 13a to 13k having a plurality of “diffraction gratings” having different grating peristaltic rotation angles has been described as an example. However, one “diffraction grating” or a grating interval is described. A panel (not shown) having a plurality of “diffraction gratings” having different values is rotated, for example, along the diffraction grating surface (dynamically rotated by a perist), and each viewpoint position is synchronized with the rotation of the panel. It is also possible to adopt a configuration in which an image to be visually recognized is switched and displayed. Even when such a configuration is adopted, by arranging the “light reflecting portion”, it is possible to suppress the emission of the 0th-order diffracted light emitted from the panel from the “light reflecting portion”. Due to the presence of the 0th-order diffracted light, a situation where a so-called ghost image is displayed can be suppressed and a clear image can be displayed.

  In addition, the usage form for displaying the “stereoscopic image by parallax” has been described as an example, but the “image” displayed by the “display device” and the “display device” is not limited to this. For example, it is possible to adopt a usage form in which a plurality of types of two-dimensional images (for example, news program images, educational program images, and animation program images) are displayed on the “display” as “different images”. it can. In such a usage mode, as an example, the “news program image” is visually recognized from the left side toward the “display”, and the “education program image” is viewed from the front toward the “display”. By making “an image of an animation program” visible from the right side toward the “display”, three viewers can visually recognize different images from one “display device”.

  Further, the display 2C (display device 1C) configured to display RGB color images has been described as an example. However, “display” and “display device” can display various color images other than RGB color images. Can also be configured. In the case of adopting such a configuration, the above-described d and ε may be appropriately adjusted for each display pixel for each color light constituting the color image. In addition, the light source 3 (3C) provided with the LED as the light emitting portion has been described as an example, but the “light source” is not limited to this, and the organic EL, CRT, liquid crystal display, plasma display, and surface conduction are not limited thereto. Various light emitting devices such as a type electron emission device display (SED) can be provided. In this case, when the above-described various light emitting devices are used for a display device for displaying a single color image, the light corresponding to one of the display pixels constituting one single color image in the light emitting device. When the above-described various light emitting devices are used in a display device for displaying a color image, the optical element for emitting light corresponds to a “light emitting portion”. The optical element for emitting the light corresponding to one of the sub-pixels of each color in one of the display pixels constituting the “corresponding” corresponds to the “light emitting part”.

  Further, the display device 2 (2C) configured to include the diffusion plate 15 has been described as an example. However, in addition to the “light diffusion portion (diffusion plate 15)”, the “light diffusion portion” or the like is damaged or dusty. It is also possible to configure a “display device” by disposing a “protection plate” for preventing the adhesion of the light and a “decorative plate” subjected to non-glare treatment.

DESCRIPTION OF SYMBOLS 1,1C display apparatus 2,2C display 3,3C Light source 4 Control part 12,12c Optical path change panel 13,13a-13k Diffraction grating panel 14,14a-14c Light reflection panel 15 Diffusing plate 20,20R, 20G, 20B, 200 Prism 30, 30R, 30G, 30B, 30a-30c Diffraction grating 40, 40R, 40G, 40B, 400 Prism F1, F2, F5 Panel surface F3 Diffraction grating surface F4a, F4b Interface L1-L5, L1R-L5R, L1G- L5G, L1B to L5B Light L3a 0th order diffracted light L3b + 1st order diffracted light L3c -1st order diffracted light L13, L14a, L14b, L15 Normal θa, θb, θp Angle

Claims (5)

A display device having a light diffraction section for diffracting light from a light source,
A light reflecting portion having a reflecting element provided so that the diffracted light can be made incident by an optical material capable of transmitting the diffracted light emitted from the light diffracting portion, and −1st order diffracted light and + 1st order as the diffracted light are provided. The first-order diffracted light of the folded light is transmitted through the reflecting element and emitted from the reflecting element, so that the images are opposed to the display unit and are different from each other from different viewpoint positions in the horizontal direction of the display unit. Is configured to display multiple images so that
The light reflecting portion reflects the 0th-order diffracted light as the diffracted light at the reflective element, so that the 0th-order diffracted light at the reflective element is more than the transmittance of any of the first-order diffracted light at the reflective element. An indicator configured to have a smaller transmittance.   2. The display according to claim 1, wherein the light reflecting portion is configured so that the zero-order diffracted light is totally reflected at an interface of the reflective element on a front side of the display. It is configured to be able to display one display pixel with a plurality of types of colored light having different wavelengths,
The light reflecting portion is provided with the reflective elements corresponding to the color lights for displaying one display pixel, and the reflective elements corresponding to the color lights for displaying the one display pixel. 3. The display device according to claim 1, wherein at least one of the optical material and the shape is different from each other. It is configured to be able to display one display pixel with a plurality of types of colored light having different wavelengths,
The light reflecting portion is provided with the reflective elements corresponding to the color lights for displaying one display pixel, and the reflective elements corresponding to the color lights for displaying the one display pixel. The display according to claim 1, wherein the two are made of the same optical material and have the same shape.   5. A display device comprising: the display according to claim 1; the light source; and a control unit that controls lighting of the light source and causes the display to display the image.

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