JP2012208224A - Display instrument and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To average densities of parallax images seen from each position in right and left directions.SOLUTION: A display device is so composed that mutually different images can be seen from N number of view positions. In the display device, a pair of diffraction gratings, consisting of two diffraction gratings, are formed to correspond to displayed pixels for the same position in two images intended to be recognized from neighboring view positions. Now, let the difference of peristaltic rotational angle between the two diffraction gratings be an angle difference P. Consider (N-2M+2) number of kinds of images that are to be seen from each of the view positions from the M-th view position (M is a rounded up natural number of N divided by 3) on the viewer's left to the M-th view position on the viewer's right. With these images, (N-2M+2-1) number of pairs of diffraction gratings are assumed, each diffraction grating being formed corresponding to a displayed pixel on the same position. Then diffraction grating panels 13, 13A, and 13B are formed in such a manner that, of the (N-2M+2-1) number of pairs of diffraction gratings, at least one pair of diffraction gratings have an angle difference P smaller than the average of angle differences P of all pairs of diffraction gratings.

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.

  For example, Japanese Patent Application Laid-Open No. 2003-140083 discloses a stereoscopic display device that displays images three-dimensionally by displaying different images from different viewpoint positions in the horizontal direction (left-right direction) so as to be visible. Has been. This stereoscopic display device is a two-dimensional image display device array (hereinafter referred to as a “display portion array”) in which a plurality of two-dimensional image display devices (hereinafter also referred to as “image display portions” to be distinguished from the stereoscopic display devices) are arranged. ”), A lens array in which a plurality of lenses are arranged corresponding to each image display section, and a plurality of openings for defining the display angle range of the image for each image display section. An aperture array, a shared lens that distributes light that has passed through each aperture of the aperture array in the horizontal direction, and a vertical diffusion plate that diffuses the light that has passed through the shared lens in the vertical direction (vertical direction) are configured. .

  In this stereoscopic display device, as shown in FIG. 44, each light Lx emitted from each image display unit of the display unit array (light for visually recognizing an image at each viewpoint position) is converted into a lens and an aperture array of the lens array. After passing through the apertures in this order, the light enters the shared lens. In the figure, the lens array, the aperture array, and the vertical diffusion plate are not shown. At this time, each light Lx is incident on each part of the shared lens according to the position of each image display part in the display part array. Thereby, each light Lx emitted from each image display unit is distributed toward each viewpoint position in the horizontal direction according to the incident position with respect to the shared lens. Each light Lx distributed in the horizontal direction is diffused in the vertical direction by the vertical diffusion plate. As a result, different images displayed on the image display units are visually recognized within a predetermined range in the vertical direction at different viewpoint positions in the horizontal direction.

JP 2003-140083 (page 5-8, FIG. 1-15)

  However, the conventional stereoscopic display device has the following problems. That is, in the conventional stereoscopic display device, each light Lx emitted from each image display unit and passing through the lens array and the aperture array in this order is distributed in the horizontal direction by the shared lens, so that each viewpoint position in the horizontal direction is divided. A configuration in which different images are visually recognized is employed. In this case, in the display unit array in the conventional stereoscopic display device, the image display units are arranged at equal intervals in the horizontal direction as illustrated in FIGS. Therefore, as shown in FIG. 44, each light Lx emitted from each image display unit is relative to the interface on the display unit array side in the shared lens (the interface on the back side of the stereoscopic display device: the upper surface in the figure). Are incident at equal intervals. Further, in a conventional stereoscopic display device, a spherical lens (in the example disclosed in the above publication) is used as a shared lens. Therefore, in the conventional stereoscopic display device, each light Lx incident on each part of the rear-side interface of the shared lens is converted into an interface on the vertical diffusion plate side of the shared lens (an interface on the front side of the stereoscopic display device: After being emitted from the side surface), it passes through one point (focal point) according to the optical design of the shared lens.

  For this reason, in the conventional stereoscopic display device, the emission angle of the light Lx of the image to be visually recognized by a person positioned near both ends in the horizontal direction (left and right sides toward the stereoscopic display device: left and right sides in the figure) The emission angle interval of the light Lx of the image (the same figure) for the person who is positioned closer to the center in the horizontal direction (the front part of the stereoscopic display device) than the interval (angles θo1, θo2,. The angle θc1, θc2,. Therefore, in the conventional stereoscopic display device, the density of each parallax image viewed near the center in the horizontal direction is lower than the density of each parallax image viewed near both ends in the horizontal direction. Near the center in the direction, the angle range where the same image (the same light Lx) is visually recognized is widened. As a result, when a stereoscopic image based on binocular parallax is visually recognized in a conventional stereoscopic display device, a situation in which one parallax image is not visually recognized by one eye and is not visually recognized as a stereoscopic image, or stereoscopic motion due to motion parallax is caused. When visually recognizing an image, each parallax image is roughly switched near the center in the horizontal direction.

  The present invention has been made in view of such problems, and has as its main object to provide a display and a display device that can average the density of parallax images at each position in the left-right direction.

  In order to achieve the above object, a display device according to the present invention is a display device including a light diffraction unit that diffracts light from a light source, and is opposed to the display device, and is different in the left-right direction of the display device. N kinds of images can be displayed so that images different from each other can be viewed from N viewpoints (N is a natural number of 4 or more), and the light diffracting unit is a diffraction grating for each display pixel. And is configured to diffract the light from the light source in each of the diffraction gratings in a predetermined direction, and from the left side toward the display, the M-th position (M is N equal to 3). (The natural number obtained by rounding up the value divided by 1) as the first viewpoint position, the Mth viewpoint position from the right side toward the display as the second viewpoint position, and in the left-right direction. Two types of images to be viewed at adjacent viewpoint positions In the diffraction grating set composed of the two diffraction gratings respectively formed corresponding to the two display pixels located at the same position in FIG. In addition, when the average value of the angle differences P of each of the (N-1) sets of diffraction grating sets is a first average value, the second viewpoint from the first viewpoint position in the left-right direction. (N−2M + 2) number of (N−2M + 2) types of images that are visually recognized at the corresponding viewpoint position up to the position in the (N−2M + 2) types of the images, corresponding to the display pixels located at the same position. The angle difference P of at least one of the (N−2M + 2-1) sets of diffraction grating sets including the diffraction gratings is configured to be smaller than the first average value. It has been.

  The display according to the present invention includes a light diffracting unit that diffracts light from a light source, and is configured to be able to display one display pixel in one image with a plurality of types of colored light having different wavelengths. The N images are different from each other in the N positions (N is a natural number of 4 or more) facing the display and differing in the left-right direction of the display. An image can be displayed, and the light diffracting unit has a diffraction grating formed corresponding to each color light for displaying the one display pixel, and the color light is defined in advance for each diffraction grating. The position of the viewpoint at the Mth position (M is a natural number obtained by rounding up a fraction of a value obtained by dividing N by 3) from the left side toward the display is defined as the first viewpoint. Position to the display Thus, the M viewpoint position from the right side is set as the second viewpoint position, and two of the display pixels located at the same position in the two types of the images to be viewed at the viewpoint positions adjacent in the left-right direction are selected. An angle difference P is defined as an angular difference P of each of the two diffraction gratings in a diffraction grating set including the two diffraction gratings respectively formed corresponding to the color lights of the same color, and (N−1) ) When the average value of the angle difference P of each of the diffraction grating sets in the set is defined as a first average value, (N−) from the first viewpoint position to the second viewpoint position in the left-right direction. 2N + 2) (N-2M + 2) types of (N-2M + 2) types of images that are visually recognized at the corresponding viewpoint positions, which are respectively formed corresponding to the same color light of the display pixels located at the same position. The angle difference P of at least one of the (N−2M + 2-1) sets of the diffraction grating sets including the respective diffraction gratings is set to be smaller than the first average value. It is configured.

  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 the display device according to the present invention, the light diffracting unit may have an average value of the angle differences P of the (N-2M + 2-1) sets of the diffraction grating sets as a second average value. The second average value is configured to be smaller than the first average value.

  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 device according to the present invention is configured to display N types of images so that different images can be viewed from N viewpoints (natural numbers of 4 or more) that differ in the left-right direction, and an optical diffraction unit However, the viewpoint position at the Mth position (natural number obtained by rounding up the value obtained by dividing N by 3) from the left side toward the display is the first viewpoint position, and the Mth viewpoint from the right side toward the display Two display pixels positioned at the same position in two types of images viewed at adjacent viewpoint positions in the left-right direction with the position as the second viewpoint position (colored light of the same color among the two display pixels positioned at the same position) ) Is defined as an angle difference P, and (N−1) sets of diffraction grating sets. Of each angle difference P Same as in (N-2M + 2) types of images that are viewed at (N-2M + 2) viewpoint positions from the first viewpoint position to the second viewpoint position in the left-right direction when the value is the first average value. (N-2M + 2-1) diffraction gratings (N-2M + 2) each formed corresponding to a display pixel located at a position (colored light of the same color of two display pixels located at the same position). ) The angle difference P of at least one of the set of diffraction grating sets is configured to be smaller than the first average value.

  In addition, the 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 and displays an image on the display.

  Therefore, according to the display device and the display device according to the present invention, at least a part of each image to be visually recognized by a person positioned near the center in the left-right direction (front portion of the display device) As a result of being able to sufficiently reduce the emission angle interval from the light diffraction section, it is possible to approach the state where the density of each parallax image at each position in the left-right direction is averaged. Thus, when viewing a stereoscopic image due to binocular parallax, different parallax images can be viewed with both eyes at any position in the left-right direction, and also when viewing a stereoscopic image due to motion parallax. As a result, it is possible to avoid the situation where the switching of the parallax images becomes rough near the center in the left-right direction. As a result, a stereoscopic image due to motion parallax can be visually recognized without a sense of incongruity.

  Further, according to the display device and the display device according to the present invention, when the average value of the angle difference P of each of the (N−2M + 2-1) diffraction grating sets is the second average value, By configuring the light diffracting unit so that the average value is smaller than the first average value, the density of each parallax image can be made closer to the averaged state at any position in the left-right direction.

It is a block diagram which shows the structure of the display apparatuses 1 and 1C (display 2 and 2C). 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 L4 emitted in the case of an image display. Sectional drawing for demonstrating the relationship of arrangement | positioning of the optical path change panel 12 (12c), the diffraction grating panel 13 (13c), the diffusion plate 14, and the light source 3 (3C) in the indicator 2 (2C) of the display apparatuses 1 and 1C. It is. It is a block diagram which shows the structure of display apparatus 1A, 1B, 1AC, 1BC (display 2A, 2B, 2AC, 2BC). It is a top view for demonstrating the relationship between indicator L2A, 2B (2AC, 2BC) and light source 3 (3C) of display apparatus 1A, 1B (1AC, 1BC), and the light L4 emitted in the case of an image display. . It is sectional drawing for demonstrating the relationship of arrangement | positioning of the diffraction grating panel 13A (13Ac) and the diffusion plate 14, and the light source 3 (3C) in the indicator 2A (2AC) of display apparatus 1A, 1AC. It is sectional drawing for demonstrating the relationship of arrangement | positioning of the diffraction grating panel 13B (13Bc) and the diffusion plate 14, and the light source 3 (3C) in the indicator 2B (2BC) of the display apparatuses 1B and 1BC. 3 is a front view of a light source 3. FIG. 3 is a front view of an optical path changing panel 12. FIG. It is a front view of the diffraction grating panels 13, 13A, 13B. It is the perspective view which looked at the diffraction grating panels 13, 13A, and 13B 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. It is sectional drawing of the diffraction grating panel 13B (13Bc). It is sectional drawing which looked at the diffusion plate 14 from the side. From the respective diffraction grating panels 13, 13A, 13B (13c, 13Ac, 13Bc) and the respective diffraction grating panels 13, 13A, 13B (13c, 13Ac, 13Bc) in the display devices 2, 2A, 2B (2C, 2AC, 2BC) It is explanatory drawing for demonstrating the relationship with the emitted light L3. 6 is an explanatory diagram for explaining a relationship between a normal line L14 of the panel surface F4 of the diffusion plate 14 and an incident direction of the light L2 with respect to the diffraction grating surface F3 of the diffraction grating panel 13. FIG. The relationship between the normal line L14 of the panel surface F4 of the diffusion plate 14 and the incident direction of the light L2 with respect to the diffraction grating surface F3 of the diffraction grating panel 13, and the relationship between the normal line L14 and the emission direction of the light L3 from the diffraction grating surface F3. FIG. 18 is a diagram illustrating the diffraction grating surface F3, the panel surface F4, the normal line L14, and the lights L2 and L3 in the direction of the arrow M in FIG. The relationship between the normal line L14 of the panel surface F4 of the diffusion plate 14 and the incident direction of the light L2 with respect to the diffraction grating surface F3 of the diffraction grating panel 13, and the relationship between the normal line L14 and the emission direction of the light L3 from the diffraction grating surface F3. FIG. 18 is a diagram illustrating the diffraction grating surface F3, the panel surface F4, the normal line L14, 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 L14 of the panel surface F4 in the diffuser plate 14, 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 F4, and the method It is the figure which looked at the lines L13 and L14 in the direction of the arrow M in FIG. It is another explanatory drawing for demonstrating the relationship between the normal line L14 of the panel surface F4 in the diffusion plate 14, 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 F4. It is the figure which looked at normal line L13 and L14 in the direction of the arrow N in FIG. It is explanatory drawing for demonstrating the grating | lattice line of each diffraction grating 30 in the diffraction grating panels 13, 13A, 13B (13c, 13Ac, 13Bc). 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. 24 is an explanatory diagram for viewing the diffraction grating surface F3, the panel surface F4, 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. 24 is another explanatory diagram for viewing the diffraction grating surface F3, the panel surface F4, 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 L14 of the panel surface F4 in the diffusion plate 14, and the output direction of the light L3 from the diffraction grating surface F3. It is a front view of light source 3C. It is a front view of the optical path change panel 12c. It is explanatory drawing for demonstrating the structure of the optical path change panel 12c. It is a front view of diffraction grating panel 13c, 13Ac, 13Bc. It is explanatory drawing for demonstrating the structure of the diffraction grating panel 13Bc. It is explanatory drawing for demonstrating an example of the indicator 2C. It is explanatory drawing for demonstrating an example of indicator 2AC. It is explanatory drawing for demonstrating an example of the indicator 2BC. 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. The angular difference of the respective perist rotation angles of the two diffraction gratings formed corresponding to the display pixels of the image viewed at the viewpoint positions adjacent in the left-right direction is the same angular difference in any diffraction grating set. It is explanatory drawing for demonstrating the relationship between the formed diffraction grating panel and the light Lz radiate | emitted from the diffraction grating panel. It is explanatory drawing for demonstrating the relationship between the display part array (each image display part) and the shared lens in the conventional stereoscopic display apparatus, the light Lx radiate | emitted from the display part array, and the light Lx deflected by the shared lens. .

  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, the display device 1 </ b> A shown in FIGS. 4 to 6, and the display device 1 </ b> B shown in FIGS. 4, 5, and 7 are all configured to be able to display stereoscopic images based on parallax. A display device (“configured to be able to display N types of images so that different images can be visually recognized from N viewpoints (natural numbers of 4 or more) that are different in the horizontal direction of the display”) Example), the display device 1 is configured to include the display device 2, the light source 3, and the control unit 4, the display device 1A is configured to include the display device 2A, the light source 3, and the control unit 4, and the display device 1B is configured to include the display device 1B. The display 2B, the light source 3 and the control unit 4 are provided.

  In the actual display devices 1, 1 </ b> A, and 1 </ b> B, as an example, 81 parallaxes defined in correspondence with the respective viewpoint positions in the left and right 81 directions (N = 81 viewpoint positions) on the front side of the display apparatus 1. N = 81 types of “horizontal × vertical = 1920 × 1080 pixels” RGB color images that are different from each other can be visually recognized, but the “display” and “display device” In order to facilitate the understanding of the configuration, 81 types of “horizontal × vertical = 1920 × 1080 pixels” single-color images that are different from each other from the respective parallax regions for the respective viewpoint positions in the left and right 81 directions correspond to each other. Configuration for visually recognizing 81 pixels (an example of “display pixels located at the same position in each image”) (displays one display pixel group in a monochromatic image group composed of 81 types of monochromatic images) The configuration of the eye) 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, a portion for displaying one display pixel group (a group of 81 display pixels corresponding to each other (located at the same position) in each image) in the single color image group includes: As shown in FIG. 8, “horizontal × vertical = 9 × 9 = 81 places” light emitting portions 10A1 to 10I9 (hereinafter, also referred to as “light emitting portion 10” when not distinguished) are provided. That is, in the light source 3 in the display devices 1, 1 </ b> A, 1 </ b> B configured to display a monochromatic image, one light emitting unit 10 is provided for each of the display pixels constituting one monochromatic image. As shown in FIGS. 3, 6, and 7, the light source 3 is perpendicular to the panel surface F <b> 1 (a surface parallel to the substrate surface of the substrate), for example, according to the control signal S from the control unit 4. The light L1 parallel to each other 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, and the diffusion plate 14 are arranged in this order toward the right side of FIG. 2, the lower side in FIG. In this case, as shown in FIG. 3, in the display device 1 configured with the display device 2, the emission direction of the light L <b> 1 from each light emitting unit 10 in the light source 3 is the optical path changing panel 12 in the display device 2. The normal direction of the panel surface F 2, the normal line of each diffraction grating surface F 3 of the diffraction grating panel 13, and the normal line of the panel surface F 4 of the diffusion plate 14. In the display device 1, the panel surface F 2 of the optical path changing panel 12, each diffraction grating surface F 3 of the diffraction grating panel 13, and the panel surface F 4 of the diffusion plate 14 are parallel to the panel surface F 1 of the light source 3. These are arranged so as to be.

  As shown in FIGS. 4 to 6, the display 2 </ b> A extends from the rear side (left side in FIGS. 4 and 6, upper side in FIG. 5) to the front side (right side in FIGS. 4 and 6, lower side in FIG. 5). The diffraction grating panel 13A and the diffusion plate 14 are arranged in this order. In this case, as shown in FIG. 6, in the display device 1 </ b> A configured to include the display 2 </ b> A, the emission direction of the light L <b> 1 from each light emission unit 10 in the light source 3 is on the panel surface F <b> 4 of the diffusion plate 14. It is configured to be parallel to the normal. Further, in this display device 1A, the panel surface F4 of the diffusion plate 14 is parallel to the panel surface F1 of the light source 3, and each diffraction grating surface F3 of the diffraction grating panel 13A is the panel surface F1 of the light source 3 and These are arranged so as to be non-parallel to the panel surface F4 of the diffusion plate 14.

  Further, as shown in FIGS. 4, 5, and 7, the display 2B is arranged from the rear side (left side in FIGS. 4 and 7, upper side in FIG. 5) to the front side (right side in FIGS. 4 and 7, lower side in FIG. 5). ), The diffraction grating panel 13B and the diffusion plate 14 are arranged in this order. In this case, as shown in FIG. 7, in the display device 1 </ b> B configured to include the display 2 </ b> B, the emission direction of the light L <b> 1 from each light emission unit 10 in the light source 3 is the diffraction grating of the diffraction grating panel 13 </ b> B. The normal direction of the surface F3 and the normal line of the panel surface F4 of the diffusion plate 14 are configured to be parallel to each other. Further, in the display device 1B, the diffraction grating surfaces F3 of the diffraction grating panel 13B and the panel surface F4 of the diffusion plate 14 are arranged so as to be parallel to the panel surface F1 of the light source 3. .

  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. 9, the optical path changing panel 12 has prisms 20A1 to 20I9 (hereinafter also referred to as “prisms 20” when not distinguished) arranged in “horizontal × vertical = 9 × 9 = 81 places”. 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.

  As shown in FIG. 3, in the display device 2, an inclined surface is formed on the surface of the optical path changing panel 12 that faces the diffraction grating panel 13 so as to gradually protrude toward the diffraction grating panel 13 toward the lower side. Each prism 20 (200) is configured (configured (disposed) so that the light L1 enters perpendicularly to the surface (panel surface F2) facing each light source 3 in each prism 20 (200). ing)). In addition, in the display device 2 (display device 1) of the present example, a configuration is adopted in which an inclined surface is formed on the front surface side of the optical path changing panel 12 to function as a “prism”. It is also possible to adopt a configuration in which a slope 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, so that a diffraction grating panel, which will be described later. The light L2 is obliquely incident on each of the 13 diffraction grating surfaces F3. In this case, since the “optical path changing element” is configured by the prism 20 (200) in the display device 2, the “optical path changing portion” can be easily manufactured using a resin material, glass, or the like. Is sufficiently reduced.

  The diffraction grating panels 13, 13 </ b> A, and 13 </ b> B are examples of “light diffraction units”, and as shown in FIGS. 3, 6, and 7, the diffraction grating panel 13 diffracts the light L <b> 2 emitted from the optical path changing panel 12. The diffraction grating panels 13A and 13B are configured to diffract the light L1 emitted from the light source 3 and to emit the light L3. In the diffraction grating panels 13, 13A, 13B, as shown in FIG. 10, the display pixels of the stereoscopic image to be displayed correspond to the display pixels of one of the monochrome image groups. Thus, “horizontal × vertical = 9 × 9 = 81” diffraction gratings 30A1 to 30I9 (hereinafter also referred to as “diffraction grating 30” when not distinguished) are formed (one diffraction grating for each display pixel). Example of formed configuration).

  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 panels 13, 13 </ b> A, 13 </ b> B in the displays 2, 2 </ b> A, 2 </ b> B configured to display a monochromatic image, one diffraction grating 30 corresponds to one light emitting unit 10 in the light source 3. One diffraction grating 30 is defined for each of the display pixels constituting one monochrome image. In FIG. 10, the grating lines of each diffraction grating 30 are shown at a pitch wider than the actual grating formation pitch. As shown in FIG. 11, each of the diffraction grating panels 13, 13A, 13B diffracts the light L2 or the light L1 in the 81 directions defined in advance for each diffraction grating 30 and emits the light. It is configured. In FIG. 11, the emission direction of the light L2 or the diffracted light (light L3) of the light L1 is indicated by arrows.

  3 and 6, as an example, the diffraction grating panels 13 and 13A are formed with each diffraction grating 30 defined on a surface facing the optical path changing panel 12 (that is, the back surface of the diffraction grating panel 13). An uneven pattern (lattice pattern) in which a plurality of parallel convex portions 31 in a plan view and a plurality of parallel concave portions 32 in a plan view are formed at a predetermined formation pitch for each region is formed. The concavo-convex pattern functions as a phase type diffraction grating 30, and is configured to diffract light L2 from the optical path changing panel 12 or light L1 from the light source 3 in a predetermined direction. In this case, as the “diffraction grating”, not only the “phase type diffraction grating” such as the diffraction grating panels 13 and 13A described above, but also the “amplitude type diffraction grating” or a diffraction grating panel 13B described later. There is a “blazed diffraction grating”.

  In addition, in the diffraction grating panels 13 and 13A having the diffraction grating 30, the light is incident obliquely on the diffraction grating surface F3 of the diffraction grating 30, so that +1 next time of the light L3 diffracted by the diffraction grating 30. Either one of the folded light and the minus first-order diffracted light has a larger output amount (light quantity) than the other output amount (the other output amount becomes smaller than either one of the output amounts).

  Therefore, as shown in FIG. 3, in the display device 2 having the diffraction grating panel 13, the traveling direction of the light L <b> 1 from the light source 3 is changed in the vertical direction by the prisms 20 of the optical path changing panel 12. The light L2 from the optical path changing panel 12 is incident obliquely on the diffraction grating surface F3 of the diffraction grating 30 in FIG. In the diffraction grating panel 13 of the display device 2, as an example, the diffraction grating surface F3 of each diffraction grating 30 is positioned on the same plane (that is, each diffraction grating surface F3 is flush), Each diffraction grating surface F3 is configured to be parallel to the panel surfaces F1, F2, and F4.

  In this case, the display having the optical path changing panel 12 in which each prism 20 is configured by forming an inclined surface 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 device 2, 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.

  On the other hand, as shown in FIG. 6, in the diffraction grating panel 13A of the display 2A configured to directly enter the light L1 from the light source 3 with respect to the diffraction grating 30 (diffraction grating surface F3), each diffraction grating 30 is provided. In order to make the light L1 incident obliquely with respect to the diffraction grating surface F3, as an example, the direction and magnitude of the inclination with respect to the panel surfaces F1 and F4 for each diffraction grating 30 (each formation region of each diffraction grating 30). And the diffraction grating surfaces F3 are formed so as to be inclined with respect to the panel surfaces F1 and F4.

  The diffraction grating panels 13 and 13A employ a configuration in which the uneven pattern formed on the back surface thereof functions as the diffraction grating 30. However, the front surface side of the diffraction grating panels 13 and 13A (opposite the diffusion plate 14). A configuration in which a concave-convex pattern is formed on the surface (the side on which the person who visually recognizes the image exists) to function as a diffraction grating can be employed (not shown). Further, in the present specification, the surfaces including the center lines in the width direction (vertical direction in FIGS. 3 and 6) of the protruding end surfaces of the convex portions 31 constituting the diffraction grating 30 in the diffraction grating panels 13 and 13A (FIGS. 3 and 6). 6 is a diffraction grating plane F3. Further, even when the cross-sectional shape of the convex portion 31 is different from that of the diffraction grating panel 13 as in the diffraction grating panel 13a shown in FIG. 12 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. 22 and the like) is also referred to as a lattice line.

  As shown in FIG. 7, as an example, the diffraction grating panel 13 </ b> B has each diffraction grating 30 defined on a surface facing the diffusion plate 14 (that is, the front surface of the diffraction grating panel 13 </ b> B: the right surface in FIG. 7). A concave / convex pattern (lattice pattern) having a sawtooth cross section is formed in each formation region, and this concave / convex pattern functions as a blazed diffraction grating 30 to diffract light L1 from the light source 3 in a predetermined direction. It is configured as follows. Also, in this diffraction grating panel 13B, a plurality of V-shaped recesses 32b (grating grooves) that are parallel to each other are formed, so that a plurality of chevron shapes are formed so that the tops 31p are parallel to each other in a straight line in plan view. The convex portions 31b are formed at a predetermined formation pitch, and the above-described concave / convex pattern (lattice pattern) is formed.

In this case, in the diffraction grating panel 13B having the blazed diffraction grating 30, the diffraction grating 30 is formed so that the formation pitch and height of each convex portion 31b satisfy a predetermined condition, so that the diffraction grating surface F3 is Even if the light to be diffracted is not incident obliquely, either the + 1st order diffracted light or the −1st order diffracted light out of the light L3 diffracted by the diffraction grating 30 is larger than the other output amount. (The emission amount of the other is smaller than the emission amount of either one). Specifically, the wavelength of the light L2 to be diffracted is “λ”, the refractive index of the “diffracting target light L2” of the optical material constituting each diffraction grating 30 is “n ₁ ”, and the formation of each convex portion 31b. When the pitch is “d (see FIG. 14)”, the height “H (see FIG. 14)” of each convex portion 31b is “H = λ / {n ₁ −√ [1− (λ / d) ^2]. ]} ”Is formed so as to satisfy the conditional expression“]} ”, the emission amount (light quantity) of either the + 1st order diffracted light or the −1st order diffracted light is maximized.

  The diffraction grating panel 13B of this example employs a configuration in which the concave / convex pattern formed on the front surface functions as the diffraction grating 30. However, the concave / convex pattern is formed on the back side of the diffraction grating panel 13B as a diffraction grating. A functioning structure can also be employed (not shown). Further, in this specification, a surface including the top 31p of each convex portion 31b constituting the diffraction grating 30 in the diffraction grating panel 13B is defined as a diffraction grating surface F3. Furthermore, in the following description, the top portion 31p or a line segment parallel to the top portion 31p (a line indicated by a solid line Lb in FIG. 22 and the like) is also referred to as a lattice line.

  In this case, in the displays 2, 2 </ b> A, 2 </ b> B configured to include the diffraction grating panels 13, 13 </ b> A, 13 </ b> B, the inclination (perist rotation angle) of the grating line with respect to the horizontal direction is made different for each diffraction grating 30. The exit direction of the diffracted light by the diffraction grating panels 13, 13A, 13B is made different for each diffraction grating 30, and thereby, N = 81 different viewpoint positions that are different in the left-right direction of the indicators 2, 2A, 2B. Thus, a configuration is employed in which light for visually recognizing different images (in this example, light L4 transmitted through the diffusion plate 14) is emitted. Specifically, in the diffraction grating panels 13, 13A, and 13B, the grating peristaltic angle of each diffraction grating 30 (the grating line of each grating when viewed from the surface on which the light L2 or the light L1 is incident). 22 (a line indicated by a solid line Lb in FIG. 22) is a horizontal state (a state parallel to the line indicated by a solid line Lc in FIG. 22) is 0 degree, and the rotation angle at which the lattice line of each lattice is left-down is plus, The rotation angle at which the grating line of the grating is lowered to the right is formed so as to be different from each other according to the direction in which the diffracted light should be emitted.

  In addition, the diffraction grating panels 13, 13A, 13B have 27th viewpoint positions (examples of “M = 81/3 = 27”) from the left side toward the displays 2, 2A, 2B. "Viewpoint position", and the 27th viewpoint position from the right side toward the display devices 2, 2A, 2B is set as the "second viewpoint position", and the same position in two types of images that are viewed at adjacent viewpoint positions in the horizontal direction The angle difference of the respective perist rotation angles of the two diffraction gratings 30 in the “diffraction grating set” composed of the two diffraction gratings 30 respectively formed corresponding to the two display pixels located at is “angle difference P”. In addition, when the average value of each “angle difference P” of “diffraction grating set” of 80 sets (example of “N-1 = 81-1 = 80”) is set to “first average value”, left and right From “first viewpoint position” to “second viewpoint position” The 29 pixels formed in correspondence with the display pixels located at the same position in the 29 types of images visually recognized at the 29 viewpoints (example of “N−2M + 2 = 81-2 · 27 + 2 = 29”). The “diffraction grating set” of at least one of the “diffraction grating sets” of 28 sets (examples of “N-2M + 2-1 = 81-2 · 27 + 2-1 = 28”) of the diffraction gratings 30 of “ It is configured to satisfy the condition that the “angle difference P” is smaller than the “first average value” (hereinafter also referred to as “first condition”).

  Further, the diffraction grating panels 13, 13 </ b> A, and 13 </ b> B are configured to calculate the average value of the “angle difference P” of the “diffraction grating set” of the above 28 sets (an example of “(N−2M + 2-1) set”). 2 ”is set to satisfy the condition that the“ second average value ”is smaller than the“ first average value ”(hereinafter also referred to as“ second condition ”). Yes. In addition, the diffraction grating panels 13, 13A, and 13B have all the “angle differences P” of the “diffraction grating set” of the above 28 sets (an example of “(N−2M + 2-1) set”) as “first”. It is configured to satisfy a condition that the value is smaller than the “average value” (hereinafter also referred to as “third condition”). Further, the diffraction grating panels 13, 13 </ b> A, and 13 </ b> B include at least one set of “angle difference P” among the “diffraction grating sets” of the above 80 sets (an example of “(N−1) set”). The “diffraction grating set” satisfies the condition (hereinafter also referred to as “fourth condition”) that exists in the “diffraction grating set” of the above 28 sets (an example of “(N-2M + 2-1) set”). It is configured as follows. Further, in the diffraction grating panels 13, 13 </ b> A, and 13 </ b> B, when the “diffractive grating set” of one or a plurality of “diffraction grating sets” continuously adjacent to each other in the center in the left-right direction, the “angular difference P” decreases stepwise. (Hereinafter, also referred to as “fifth condition”).

  The diffusion plate 14 is an example of a “light transmission panel”, and is a “light diffusion portion” that diffuses the light L3 diffracted by the diffraction grating panels 13, 13A, and 13B in the vertical direction of the indicators 2, 2A, and 2B. As an example, it is composed of a lenticular lens formed in a flat plate shape with a resin material having optical transparency. As shown in FIG. 15, as an example, the diffusion plate 14 includes 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). Further, in the display units 2, 2 </ b> A, 2 </ b> B, as an example, the above-described convex lens is formed so that a plurality of convex lenses are positioned per one diffraction grating 30 in the diffraction grating panels 13, 13 </ b> A, 13 </ b> B. Is configured. As a result, in the indicators 2, 2A, 2B, the light L3 diffracted by the diffraction grating panels 13, 13A, 13B is transmitted through the diffusion plate 14 and diffused in the vertical direction (vertical direction) by the convex lenses. It is emitted as L4.

  In this case, in this specification, the surface of the diffusion plate 14 that faces the diffraction grating panels 13, 13A, 13B (that is, the back surface of the diffusion plate 14) is defined as a panel surface F4. 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 reflecting panel) (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 F4.

  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 displays 2, 2 </ b> A, 2 </ b> B, thereby causing each light emitting unit 10 in the light source 3 to be stereoscopically displayed. It is turned on according to the brightness of each display pixel of the visual image. The actual display devices 1, 1 </ b> A, and 1 </ b> B include an image processing unit that processes image data and image signals output from an external device, and the control unit 4 includes data and signals processed by the image processing unit. The stereoscopic image is displayed on the display device 2 based on the above, but in order to facilitate understanding of the “display device” and the “display device”, other than the display devices 2, 2 A, 2 B, the light source 3 and the control unit 4. Descriptions and illustrations regarding the components are omitted.

  When displaying a stereoscopic image by the display devices 1, 1 </ b> A, 1 </ b> B (display devices 2, 2 </ b> A, 2 </ b> B), the control unit 4 outputs a control signal S to the light source 3, whereby each stereoscopic image to be displayed is displayed. Each light emitting unit 10 is turned on with brightness according to the brightness of the display pixel. At this time, as shown in FIG. 3, in the display device 1 (display device 2), each light emitting portion 10 of the light source 3 is parallel to the normal line of the diffraction grating surface F <b> 3 of each diffraction grating 30 in the diffraction grating panel 13. Each light L <b> 1 emitted in the direction 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. As shown in FIG. 6, in the display device 1 </ b> A (display 2 </ b> A), as described above, each diffraction grating 30 of the diffraction grating panel 13 </ b> A is relative to the panel surface F <b> 4 of the diffusion plate 14 and the panel surface F <b> 1 of the light source 3. Accordingly, 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 panel surface F4 of the diffusion plate 14 is the diffraction grating of the diffraction grating panel 13. Incidently incident on the surface F3. Further, as shown in FIG. 7, in the display device 1B (display device 2B), the light emitting sections 10 of the light source 3 are oriented in parallel to the normal line of the diffraction grating surface F3 of each diffraction grating 30 in the diffraction grating panel 13B. Each emitted light L1 enters perpendicularly to the diffraction grating surface F3.

  The light L2 or light L1 incident on the diffraction grating panels 13, 13A, 13B (diffraction grating surface F3) is diffracted by each diffraction grating 30, and emitted as light L3 (diffracted light). At this time, in the display devices 1, 1A, 1B (displays 2, 2A, 2B), as described above, the diffraction gratings 30 in the diffraction grating panels 13, 13A, 13B should emit the light L3. In accordance with the direction, the inclination of the lattice line (perist rotation angle) is defined and formed. As a result, as shown in FIG. 11, the light L3 from each diffraction grating 30 is emitted from the diffraction grating panels 13, 13A, 13B so as to spread radially in the left and right 81 directions at predetermined intervals.

  At this time, in the displays 2 and 2A, as described above, the light L2 or the light L1 is incident obliquely on the diffraction grating surface F3 of each diffraction grating 30 in the diffraction grating panels 13 and 13A. Further, in the display device 2B, the light L1 from the light source 3 enters the blazed diffraction grating 30. Therefore, in the indicators 2, 2A and 2B, when the light L2 or the light L1 is diffracted by each diffraction grating 30, the intensity of the + 1st order diffracted light is sufficiently increased, and the diffraction grating panel 13, The -1st order diffracted light is not emitted from 13A, 13B to the diffuser plate 14 side, or the amount of the -1st order diffracted light emitted to the diffuser plate 14 side is extremely small, and only the + 1st order diffracted light and the 0th order diffracted light are diffused. 14 is emitted. For this reason, in the displays 2, 2A, 2B, the utilization efficiency of the light L1 from the light source 3 is sufficiently improved, and the + 1st order diffracted light having a sufficiently large amount of light is used as light for visually recognizing a stereoscopic image. By using the display pixel, the display pixel corresponding to the + 1st order diffracted light is visually recognized sufficiently brightly.

  On the other hand, the light L3 (+ 1st order diffracted light and 0th order diffracted light) emitted from the diffraction grating panels 13, 13A, 13B is vertically transmitted by a lenticular lens constituting the diffusion plate 14, as shown in FIGS. As shown in FIGS. 2 and 5, the light is diffused in the direction and emitted as light L4 toward the front of the display devices 2, 2A, 2B (display devices 1, 1A, 1B). Thereby, the viewing area in the vertical direction (vertical direction) is expanded for each parallax area in the left and right 81 directions, and a predetermined height in the vertical direction is set for each position in the left and right 81 directions in front of the display devices 1, 1A, 1B. Within the range, an image corresponding to each viewpoint position (an image having each light L4 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, the direction of the arrows A1 and A2 shown in FIGS. 2 and 5 (left and right direction) while a person who views the image visually recognizes the image displayed on the display devices 1, 1A and 1B (displays 2, 2A and 2B). ), The images displayed on the display devices 1, 1A, 1B (displays 2, 2A, 2B) are recognized as stereoscopic images by motion parallax. The

  In this case, two diffraction gratings in a diffraction grating set formed of two diffraction gratings respectively formed corresponding to two display pixels located at the same position in two types of images viewed at adjacent viewpoint positions in the left-right direction. In a display (display device) having a diffraction grating panel formed so that the angle difference between the respective perist rotation angles is the same in any diffraction grating set, the light emitted from each image display unit is transmitted. In the same manner as a conventional stereoscopic display device (see FIG. 44) in which a configuration in which a shared lens is distributed in the horizontal direction is adopted, as shown in FIG. 43, both end portions in the left-right direction (on the left and right sides toward the display: According to the emission angle interval (angles θo1, θo2,..., Shown in the figure) of the light Lz of the image to be viewed by a person located on the left or right side in the figure from the diffraction grating panel. In addition, the emission angle interval of the light Lz of the image from the diffraction grating panel for viewing by a person located near the center in the left-right direction (front part of the display) (angles θc1, θc2,. Is bigger.

  Therefore, in a display (display device) having a diffraction grating panel formed so that the angle difference of the peristaltic rotation angle of each diffraction grating set is the same in any diffraction grating set, both end portions in the left-right direction The density of each parallax image viewed near the center in the left-right direction is lower than the density of each parallax image viewed near. For this reason, the angle range in which the same image (the same light Lz) is visually recognized becomes wider near the center in the left-right direction. As a result, when viewing a stereoscopic image by binocular parallax, one parallax image is obtained in one eye. When a stereoscopic image due to motion parallax is viewed without being visually recognized as a stereoscopic image, switching between parallax images becomes coarser near the center in the left-right direction.

  On the other hand, as shown in FIG. 16, in the display devices 1, 1 </ b> A, 1 </ b> B (display devices 2, 2 </ b> A, 2 </ b> B), the left and right sides toward the display devices 2, 2 </ b> A, 2 </ b> B : Light L3 of the image (in this example, light L4 diffused in the vertical direction by the diffuser plate 14) from the diffraction grating panels 13, 13A, 13B to be viewed by a person located on the left or right side in the figure The diffraction grating panel 13 of the light L3 (L4) of the image to be viewed by a person positioned near the center in the left-right direction (displays 2, 2A, 2B) and the emission angle interval (angle θ shown in the figure) The output angle interval from 13A and 13B (angle θ shown in the figure) is equal to or substantially equal to each other.

  Therefore, in the display devices 1, 1 </ b> A, 1 </ b> B (displays 2, 2 </ b> A, 2 </ b> B), the density of each parallax image viewed near both ends in the left-right direction and each parallax image viewed near the center in the left-right direction. Are equal to each other or nearly equal to each other. For this reason, the angle range in which the same image is viewed is the same at any position in the left-right direction. As a result, when viewing a stereoscopic image due to binocular parallax at any position in the left-right direction, Even when different parallax images are visually recognized and a stereoscopic image due to motion parallax is visually recognized, a situation in which the switching of the parallax images becomes coarse near the center in the left-right direction is avoided.

  Next, the diffraction grating surfaces F3 of the diffraction grating panels 13, 13A, 3B and the panel surface F4 of the diffusion plate 14 in the above-described displays 2, 2A, 2B, and the light L2 from the optical path changing panel 12 (or from the light source 3). The relationship between the light L1) and the light L3 diffracted by the diffraction grating panels 13, 13A, 13B will be described with reference to the drawings.

  As described above, in the display 2, the light L1 from the light source 3 is deflected downward by the optical path changing panel 12 and is incident on the diffraction grating surface F3 of the diffraction grating 30 as light L2, whereas the display 2A 2B, the light L1 from the light source 3 is directly incident on the diffraction grating surface F3 of the diffraction grating 30, but the light (diffracted light) incident on the diffraction grating surface F3 of the diffraction grating 30 is light. The relationship between the diffraction grating surface F3 and the panel surface F4, and the light L2 and L1 to be diffracted and the light L3 diffracted by the diffraction grating 30 is different depending on whether the light is L2 or light L1. 2 and the indicators 2A and 2B are basically the same, and an example of the indicator 2 will be described below in order to facilitate understanding of these relationships. In addition, the display 2 configured with the diffusion plate 14 will be described as an example. However, in the display configured with the “light transmission panel” other than the “diffusion plate (light diffusion portion)”, The “light transmissive panel” and “light transmissive panel surface” in the display device correspond to “diffuser plate 14” and “panel surface F4” in the following description.

In this display device 2, an X component (diffusion) at an angle formed by the normal line L 14 of the panel surface F 4 of the diffusion plate 14 and the incident direction of the light L 2 incident on the diffraction grating surface F 3 of each diffraction grating 30 of the diffraction grating panel 13. It is a component corresponding to the horizontal direction of the plate 14, 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 F4 obliquely to the right is defined as plus. , The angle in which the incident direction of the light L2 intersects diagonally leftward with respect to the panel surface F4 is defined as “αX (see FIGS. 17 and 18)”,
The normal line L14 of the panel surface F4 in the diffusion plate 14 (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 diffuser plate 14, and the incident direction of the light L 2 is relative to the panel surface F 4 when viewed from the surface on which the light L 2 is incident). “ΑY (see FIGS. 17 and 19)” is an angle in which the angle of the state of crossing diagonally downward is positive, and the angle of incidence of the light L2 in the state of crossing diagonally upward to the panel surface F4 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 L14 of the panel surface F4 (a component corresponding to the horizontal direction of the diffuser plate 14 when viewed from the surface on the light incident side) The angle when the normal line L13 of the diffraction grating surface F3 intersects diagonally leftward with respect to the panel surface F4 is positive, and the normal line L13 of the diffraction grating surface F3 intersects diagonally rightward with respect to the panel surface F4. The angle that makes the angle minus) is “γX (see FIG. 20)”,
The Y component (the component corresponding to the vertical direction (vertical direction) of the diffusing plate 14 and the light L2 incident surface) at the inclination angle of the normal line L13 of the diffraction grating surface F3 with respect to the normal line L14 of the panel surface F4 When viewed, the angle of the state in which the normal line L13 of the diffraction grating surface F3 intersects diagonally upward with respect to the panel surface F4 is positive, and the normal line L13 of the diffraction grating surface F3 is diagonally downward with respect to the panel surface F4. The angle in which the angle of the intersecting state is minus) is “γY (see FIG. 21)”,
The perist rotation angle (the line indicated by the solid line Lb in FIG. 22) of each grating in the diffraction grating plane F3 of the diffraction grating 30 in the diffraction grating plane F3 is horizontal when viewed from the surface on which the light L2 is incident. (A state parallel to the line indicated by the solid line Lc in FIG. 22) is 0 degree, the rotation angle at which the lattice line of each lattice is lowered to the left is positive, and the rotation angle at which the lattice line of each lattice is downward is negative. Angle) is “ε (see FIG. 22)”,
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. 23 and 24)”, which is an angle in which the incident angle in the direction 30 is negative), and 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. 23 and 25)”, 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 FIGS. 26 and 14)”,
The y component (diffraction grating plane 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. 26) 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 of (negative angle) is “δy (see FIGS. 26 and 27)”,
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. 28 and 24)” 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. 28 and 25)” 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, the X component (the component corresponding to the left-right direction of the diffusion plate 14) in the angle formed by the normal L14 of the panel surface F4 and the emission direction of the light L3 emitted from the diffraction grating surface F3, the light L3 being the diffusion plate 14, the angle of the state in which the emission direction of the light L <b> 3 intersects obliquely leftward with respect to the diffuser plate 14 when viewed from the surface on the incident side toward the plane 14 is plus, and the emission direction of the light L <b> 3 is relative to the diffuser plate 14. “ΒX (see FIGS. 29 and 18)”, which is an angle in a state of crossing diagonally rightward, and the normal line L14 of the panel surface F4 and the light L3 emitted from the diffraction grating surface F3. Y component in the angle formed by the direction (the component corresponding to the vertical direction (vertical direction) in the diffuser plate 14), and when viewed from the surface on the side where the light L3 enters the diffuser plate 14, the emission direction of the light L3 Is against the diffuser 14 “ΒY (see FIGS. 29 and 19)” 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 indicators 2, 2A, 2B, the light beams are incident on the diffraction grating 30 in the diffraction grating panel 13 based on the above six formulas so that the above-mentioned “βX” and “βY” are at desired angles. “ΑX”, “αY”, “ε”, “d”, “γX”, and “γY” may be appropriately adjusted according to “λ” of the light L2 or the light L1 to be generated. In this case, as the absolute value of “αy” becomes larger than 0 °, the −1st order diffracted light (or + 1st order diffracted light) decreases, and the light is not emitted when the condition described later is satisfied. Further, as the −1st order diffracted light (or + 1st order diffracted light) decreases, the + 1st order diffracted light (or −1st order diffracted light) increases.

  17 to 19, 23 to 25, 28, and 29, 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 F4, and the actual light path in the display 2 Are shown in different states. In each of these drawings, as an example, “Pelist rotation angle ε ≠ 0 °” and “the inclination angle of the normal L13 of the diffraction grating surface F3 with respect to the normal L14 of the panel surface F4 is 0 ° (γX = 0 °). , ΓY = 0 °) ”.

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

  In order to distinguish from the configuration of the display devices 1, 1 </ b> A, 1 </ b> B for displaying monochromatic images, the display devices 1, 1 </ b> A, 1 </ b> B capable of displaying color images are referred to as display devices 1 </ b> C, 1 </ b> AC, 1 </ b> BC. . In addition, the display devices 2C, 1AC, and 1BC in the display devices 2C, 2A, and 2B and the light source 3 are distinguished from the display devices 2 and 2A and 2B and the light source 3 in the display devices 1, 1A and 1B. , 2AC, 2BC and light source 3C. Further, for the optical path changing panel 12 in the display 2C and the diffraction grating panels 13, 13A, 13B in the displays 2C, 2AC, 2BC, the optical path changing panel 12 in the display 2 for monochromatic image display, and for monochromatic image display. In order to distinguish from the diffraction grating panels 13, 13A, 13B in the display units 2, 2A, 2B, the optical path changing panel 12c and the diffraction grating panels 13c, 13Ac, 13Bc are referred to. In addition, constituent elements having the same functions as those of the display devices 1, 1 </ b> A, 1 </ b> B for displaying monochromatic images 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 device 2C) shown in FIGS. 1 to 3, as an example, the shape or material of each prism 20 constituting the optical path changing panel 12c should be refracted (the traveling direction should be changed). The above-mentioned problems relating to color bleeding can be obtained by making the pitches (d) of the convex portions 31 constituting the diffraction gratings 30 different from each other according to the wavelength of the color light to be diffracted. Overcoming. Further, in the display device 1AC (display device 2AC) shown in FIGS. 4 to 6 and the display device 1BC (display device 2BC) shown in FIGS. , 31b are made different from each other in accordance with the wavelength of the color light to be diffracted to overcome the above-mentioned problem of color bleeding.

  In the display devices 2C, 2AC, and 2BC in the actual display devices 1C, 1AC, and 1BC, as an example, from each parallax region for each viewpoint position in the left and right 81 directions on the front side of the display devices 1C, 1AC, and 1BC, 81 types of “horizontal × vertical = 1920 × 1080 pixels” RGB color images that are different from each other depending on the direction can be viewed, but the display devices 1C, 1AC, 1BC and the displays 2C, 2AC are displayed. In order to facilitate understanding of the configuration of 2BC, a configuration for visually recognizing one display pixel of RGB color images for each parallax region for each viewpoint position in the left and right 81 directions will be described.

  In this case, as an example, as shown in FIG. 30, the light source 3C has a light emitting unit 10 (light emitting units 10A1R to 10I9R: red sub-pixels) that emits light L1R (red color light): these are not distinguished below. 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 FIGS. 31 to 37 and FIGS. 1 and 4 to be referred to later, elements related to red (R) are denoted by “R”, and elements related to green (G) are assigned. A symbol “G” is attached, and elements related to blue (B) are attached 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 positions of the prisms 20 for the lights L1R, L1G, and L1B in 12c and the positions of the diffraction gratings 30 for the lights L1R, L1G, and L1B in the diffraction grating panels 13c, 13Ac, and 13Bc are indicated by the light emitting portions 10R and 10G. , 10B can be arranged at arbitrary positions (not shown) by arranging the light emitting units 10R, 10G, 10B for emitting each color light for visually recognizing one display pixel.

  As shown in FIG. 31, the optical path changing panel 12c changes, for example, the traveling direction of the light L1R emitted from each light emitting portion 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 is formed of a resin material having optical transparency so that the apex angle θp of the prisms 20R, 20G, and 20B becomes an angle shown in FIG. Thereby, in this optical path changing panel 12c, the light L2R emission angle from the prism 20R, the light L2G emission angle from the prism 20G, and the light L2B emission angle from the prism 20B are equal to each other (30 in this example). .0 °). In this case, the emission angles of the lights L2R, L2G, and L2B are equal to “αY” described above. For this reason, in the display device 2C provided with the optical path changing panel 12c, the incident angles of the lights L2R, L2G, and L2B to the diffraction gratings 30 in the diffraction grating panel 13c are equal to each other, as shown in FIG.

  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).

  As shown in FIG. 33, the diffraction grating panels 13c, 13Ac, and 13Bc have a diffraction grating 30 for diffracting the light L2R or the light L1R (diffraction gratings 30A1R to 30I9R: hereinafter, “diffraction grating 30R” when they are not distinguished from each other). Diffraction grating 30 for diffracting light L2G or light L1G (diffractive gratings 30A1G to 30I9G: hereinafter also referred to as “diffraction grating 30G”), and light L2B or light L1B are diffracted. Diffraction gratings 30 (diffraction gratings 30A1B to 30I9B: hereinafter also referred to as “diffraction grating 30B” when not distinguished from each other) are arranged in this order in the vertical direction (vertical direction), and one diffraction grating 30R, One color display pixel is visually recognized by one diffraction grating 30G and one diffraction grating 30B. (Example of configuration in which one diffraction grating for each color light is formed for displaying one display pixel) which Configured as color lights diffracted respectively for.

  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 the diffraction grating panels 13c, 13Ac, and 13Bc, one diffraction grating 30 (diffraction grating 30R) corresponding to one light emitting unit 10 (any of the light emitting units 10R, 10G, and 10B) in the light source 3C. , 30G, or 30B), and one diffraction grating 30 (diffraction gratings 30R, 30G, and 30B) for each sub-pixel of each color that constitutes one of the display pixels that constitute one color image. Any one) is prescribed. In addition, the diffraction grating panels 13c, 13Ac, 13Bc are similar to the diffraction grating panels 13, 13A, 13B in the above-described displays 2, 2A, 2B for displaying monochromatic images. It is configured to satisfy.

  Further, in the display devices 2C, 2AC, and 2BC of this example, in order to emit each color light for visually recognizing one color display pixel from the diffusion plate 14 in the same direction in the left-right direction, one color display pixel is displayed. In the state where the inclinations of the diffraction grating surface F3 in the diffraction gratings 30R, 30G, and 30B for diffracting each color light (light L2 or light L1) with respect to the panel surface F4 of the diffusion plate 14 are equal to each other, this one color display pixel For the diffraction gratings 30R, 30G, and 30B that diffract each color light (light L2 or light L1) for displaying the light, a grating formation pitch d (convex portion 31) in the diffraction grating 30 that diffracts the light L2 having a short wavelength λ. , 31b forming pitch d), the grating forming pitch d (convex portion 3) in diffraction grating 30 that diffracts light L2 having a longer wavelength λ The diffraction grating panel 13c is formed so that the formation pitch d) of 1 and 31b is larger.

  Specifically, with respect to the grating formation pitch d (the formation pitch d of the convex portions 31 and 31b), 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. 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 panels 13c and 13Ac, the grating in the diffraction grating 30R that diffracts the light L2R having the “wavelength λ = 633 nm” is the light L2G having the “formation pitch d = 633 nm” and the “wavelength λ = 532 nm”. The grating in the diffraction grating 30G that diffracts λ 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” (“each pitch Example of “configuration in which the pitch of the grating in the diffraction 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.

Further, in the diffraction grating panel 13Bc, the grating in the diffraction grating 30R that diffracts the light L2R is “formation pitch d = 853 nm”, the grating in the diffraction grating 30G that diffracts the light L2G is “formation pitch d = 717 nm”, and the light L2B The grating in the diffraction grating 30B that diffracts the light beam is “formation pitch d = 636 nm”. In this case, in the diffraction grating panel 13Bc of this example, “H = λ / {n ₁ −√ [1− (λ / d) ² ]}” described above according to each color light (light L2) to be diffracted. Each diffraction grating 30R, 30G, 30B is formed so as to satisfy the conditional expression. Specifically, in the diffraction grating panel 13Bc, the formation pitch (d) of the convex portions 31b is determined according to the wavelength (λ) of the diffracted light L2 and the refractive index (n ₁ ) of the light L2 to be diffracted. In addition, the diffraction gratings 30R, 30G, and 30B are formed such that the height (H) of each projection 31b is as shown in FIG. As a result, in this diffraction grating panel 13Bc, the amount of emitted light (amount of light) of either the + 1st order diffracted light or the −1st order diffracted light does not enter the diffraction grating surface F3 obliquely. (The other output amount is smaller than one of the output amounts).

  In the display devices 1C, 1AC, 1BC (display devices 2C, 2AC, 2BC), the light L2 emitted from the light source 3C and refracted by the optical path changing panel 12c or the light L1 emitted from the light source 3C Diffracted by the diffraction grating 30 and distributed in the left and right 81 directions and diffused in the vertical direction (vertical direction) by the diffuser plate 14 to widen the viewing area in the vertical direction (vertical direction) for each parallax region in the left and right 81 directions. A configuration (a configuration in which different parallax images are viewed in the left-right direction and displayed so that the same parallax image is viewed in the vertical direction) is employed.

  In this case, as shown in FIG. 16, in the display devices 1C, 1AC, 1BC (display devices 2C, 2AC, 2BC), as described above, the display devices 1C, 1AC, 1BC (display devices 2C, 2AC, 2BC) ), The image light L3 (diffuse in this example) for viewing by persons located near both ends in the left-right direction (left and right sides of the display units 2C, 2AC, 2BC: left and right sides in the figure). The emission angle interval (angle θ shown in the figure) of the light L4 diffused in the vertical direction by the plate 14 from the diffraction grating panels 13c, 13Ac, and 13Bc and the center in the horizontal direction (displays 2C, 2AC, and 2BC) ) Is equal to the emission angle interval (angle θ shown in the figure) of the light L3 (L4) of the image from the diffraction grating panels 13c, 13Ac, and 13Bc to be viewed by a person located at The angle is almost equal.

  A specific example will be described with reference to FIGS. 35 to 37, 81 pixels (pixels A1 to I9) corresponding to 81 types of parallax images to be viewed at each of N = 81 viewpoint positions that are different in the left-right direction of the display devices 2C, 2AC, and 2BC. The parameters relating to some of the pixels of “display pixels located at the same position in each image”) are illustrated. In this case, in the display devices 2C, 2AC, 2BC, as an example, the diffraction grating 30 of the pixels A1, B1,..., I1, A2,. And the absolute angle of the peristal rotation angle of the diffraction grating 30 of the pixels I9, H9,..., A5, I8,. The values coincide with each other around the pixel E5 corresponding to the parallax image viewed at the viewpoint position in the center. Therefore, FIGS. 35 to 37 mainly illustrate pixels corresponding to a parallax image that is viewed at a viewpoint position on the right side of the viewpoint position at the center.

  35 to 37, the viewpoint position where the light L3 (L4) corresponding to the pixel I3 is visually recognized corresponds to the “first viewpoint position”, and the light L3 (L4) corresponding to the pixel A7 is visually recognized. The viewpoint position to be performed corresponds to the “second viewpoint position”. Furthermore, in these examples, 80 sets corresponding to 80 sets of pixels A1, B1, B1, C1,..., H1, I1, I1, A2, A2, B2,. Each of the diffraction gratings 30 corresponds to a “diffraction grating set”.

  In the display devices 2C, 2AC, and 2BC (display devices 1C, 1AC, and 1BC) shown in FIGS. 35 to 37, 29 viewpoint positions (center position) from the “first viewpoint position” to the “second viewpoint position” described above. Corresponding to display pixels (in this example, 29 display pixels from the display pixel corresponding to the pixel I3 to the display pixel corresponding to the pixel A7) in 29 types of images visually recognized at the point of view). Thus, at least one “diffraction grating set” out of 28 “diffraction grating sets” composed of 29 diffraction gratings 30 formed in this manner (in this example, all 28 sets are all “diffraction grating sets”). “Angle difference P (value of“ * 1 ”)” is an average value (“first average value” of each of the 80 “diffraction grating sets”) (“first average value”: indicator 2C, In AC, 0.96 °, and in the display 2BC, 1. 3 °) is smaller than the of the "first condition" and the "third condition" is a diffraction grating panel 13c to be filled, 13Ac, 13bc is formed.

  In addition, in the display devices 2C, 2AC, 2BC (display devices 1C, 1AC, 1BC) shown in FIGS. 35 to 37, the average value of the “angle difference P” of each of the 28 “diffraction grating sets” (the “first” 2 ”: 0.88 ° in the display units 2C and AC and 0.93 ° in the display unit 2BC) is smaller than the above“ first average value ”. The diffraction grating panels 13c, 13Ac, and 13Bc are configured so that the “condition” is satisfied.

  Furthermore, in the displays 2C, 2AC, and 2BC (display devices 1C, 1AC, and 1BC) shown in FIGS. 35 to 37, at least one set having the smallest “angle difference P” among the 80 “diffraction grating sets”. (In the display devices 2C and AC, a “diffraction grating set” consisting of a pair of diffraction gratings 30 corresponding to the pixels D5 and E5 and a “diffraction grating set” consisting of a pair of diffraction gratings 30 corresponding to the pixels E5 and F5. In the display BC, two sets of “diffraction grating sets” composed of a pair of diffraction gratings 30 corresponding to the pixels C5 and D5, and “diffraction grating sets” composed of a pair of diffraction gratings 30 corresponding to the pixels D5 and E5, “Diffraction grating set” of “Diffraction grating set” consisting of a pair of diffraction gratings 30 corresponding to the pixels E5 and F5 and “Diffraction grating set” consisting of a pair of diffraction gratings 30 corresponding to the pixels F5 and G5). But the above 28 Grating panel 13c as "fourth condition" that the operating point is present in the "diffraction grating pairs" within are met, 13Ac, it is 13Bc are constituted of.

  In addition, in the display devices 2C, 2AC, and 2BC (display devices 1C, 1AC, and 1BC) shown in FIGS. 35 to 37, one “diffraction grating set” or consecutively adjacent to the above 80 “diffraction grating sets”. The diffraction grating panels 13c, 13Ac, and 13Bc are configured so that the “fifth condition” that the “angle difference P” decreases stepwise toward the center in the left-right direction of the matching “diffraction grating sets”. Yes.

  Therefore, in the displays 2C, 2AC, and 2BC (display devices 1C, 1AC, and 1BC), the diffraction grating panel of the light L3 of the image to be viewed by a person positioned near both end portions in the left-right direction (left side and right side). Output angle intervals from 13c, 13Ac, 13Bc (in this example, the output angle interval of the light L4 diffused in the vertical direction by the diffusion plate 14: the value of “* 2”) and the central portion in the horizontal direction (display Of the light L3 of the image to be visually recognized by a person located in the front part of the light (13c, 13Ac, 13Bc) (in this example, the light L4 emission angle interval: the value of “* 2”). The angular intervals are equal (in this example, 1.0 ° intervals). Thereby, the density of each parallax image visually recognized near the both ends in the left-right direction and the density of each parallax image visually recognized near the center in the left-right direction are equal to each other or substantially equal. .

  In this way, in the indicators 2, 2A, 2B (2C, 2AC, 2BC), they are different from each other from N viewpoints (natural numbers of 4 or more: N = 81 in this example) that are different in the left-right direction. N types of images (81 types in this example) can be displayed so that the images to be viewed can be displayed, and the diffraction grating panels 13, 13A, 13B (13c, 13Ac, 13Bc) are displayed on the display units 2, 2A, The viewpoint position of the Mth position from the left side toward 2B (2C, 2AC, 2BC) (a natural number obtained by rounding up the fraction obtained by dividing N by 3: in this example, the 27th position from the left side) The position of the Mth point from the right side (in this example, the 27th point from the right side) toward the display devices 2, 2A, 2B (2C, 2AC, 2BC) is referred to as a “second viewpoint position”. Visualize at viewpoint positions adjacent in the left-right direction 2 A “diffraction grating set” composed of two diffraction gratings 30 respectively formed corresponding to two display pixels located at the same position in the same image (colored light of the same color in the two display pixels located at the same position) The angle difference P of each of the two peristaltic rotation angles of the two diffraction gratings 30 is defined as an angle difference P, and each of the angle differences P of the (diffraction grating sets) of (N−1) sets (80 sets in this example) When the average value is “first average value”, (N−2M + 2) locations (29 locations in this example) from “first viewpoint position” to “second viewpoint position” in the left-right direction. Corresponds to the display pixels located at the same position (colored light of the same color in two display pixels located at the same position) in (N-2M + 2) types (29 types in this example) of images visually recognized at the viewpoint position (N-2M + ) (N-2M + 2-1) sets (28 sets in this example) each consisting of 29 (29 in this example) diffraction gratings 30 (in this example, at least one set (in this example, The angle difference P of all 28 sets) “diffraction grating sets” is configured to be smaller than the “first average value”.

  Further, in the display devices 1, 1A, 1B (1C, 1AC, 1BC), the display units 2, 2A, 2B (2C, 2AC, 2BC), the light source 3 (3C), and the light source 3 (3C) are provided. And a control unit 4 that controls lighting and displays images on the display units 2, 2A, 2B (2C, 2AC, 2BC).

  Accordingly, the display devices 1, 2A, 2B (2C, 2AC, 2BC) and the display devices 1, 1A, 1B (1C, 1AC) configured to include the display devices 2, 2A, 2B (2C, 2AC, 2BC). , 1BC), at least part of each image to be visually recognized by a person located near the center in the left-right direction (front part of the display), the diffraction grating panels 13, 13A, As a result of being able to sufficiently reduce the emission angle interval from 13B (13c, 13Ac, 13Bc), it is possible to approach the state where the density of each parallax image at each position in the left-right direction is averaged. Thus, when viewing a stereoscopic image due to binocular parallax, different parallax images can be viewed with both eyes at any position in the left-right direction, and also when viewing a stereoscopic image due to motion parallax. As a result, it is possible to avoid the situation where the switching of the parallax images becomes rough near the center in the left-right direction. As a result, a stereoscopic image due to motion parallax can be visually recognized without a sense of incongruity.

  Further, according to the indicators 2, 2A, 2B (2C, 2AC, 2BC), the average value of the angle difference P of each of the (N-2M + 2-1) “diffraction grating sets” is set to “second”. When the diffraction grating panels 13, 13A, 13B (13c, 13Ac, 13Bc) are configured so that the “second average value” is smaller than the “first average value”. In any position in the left-right direction, the density of each parallax image can be made closer to the averaged state.

  In this case, according to the indicators 2, 2A, 2B (2C, 2AC, 2BC), all the angle differences P of the (N−2M + 2-1) “diffraction grating sets” are all “first”. Since the diffraction grating panels 13, 13A, 13B (13c, 13Ac, 13Bc) are configured to be smaller than the “average value”, the density of each parallax image is averaged at any position in the horizontal direction. can do.

  Further, according to the indicators 2, 2A, 2B (2C, 2AC, 2BC), one “diffraction grating set” or a plurality of consecutively adjacent “diffraction grating sets” has an angular difference toward the center in the left-right direction. Since the diffraction grating panels 13, 13A, 13B (13c, 13Ac, 13Bc) are configured so that P gradually decreases, when viewing a stereoscopic image due to motion parallax, from the viewpoint positions at both ends in the left-right direction. It is possible to avoid a situation in which the density of the parallax image changes suddenly when moving toward the central viewpoint position and when moving from the central viewpoint position toward the left and right viewpoint positions. it can.

  The configurations of the “display device” and the “display device” are limited to the configurations of the display devices 2, 2A, 2B (2C, 2AC, 2BC) and the display devices 1, 1A, 1B (1C, 1AC, 1BC). Not. For example, all of the “first condition” to “fifth condition” are satisfied, and the emission angle intervals of the light L3 (L4) from the diffraction grating panels 13, 13A, 13B (13c, 13Ac, 13Bc) are mutually different. The example in which the angles are equal or almost equal has been described, but after satisfying all of the “first condition” to “fifth condition”, the diffraction grating panel 13 of the light L3 (L4), The emission angle interval from 13A, 13B (13c, 13Ac, 13Bc) can also be configured to be slightly different within a certain angle range. Further, it may be configured to satisfy only the “first condition” or may be configured to satisfy only two of the “first condition” and the “second condition”. Even when these configurations are employed, the diffraction grating panel 13 of the light L3 of the image is displayed on at least a part of each image to be visually recognized by a person positioned near the center in the left-right direction (front part of the display). , 13A, 13B (13c, 13Ac, 13Bc) can be reduced to some extent.

Further, 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, for example, a plurality of convex portions 31 and 31b that are linear in a plan view and parallel to each other and a plurality of concave portions 32 and 32b that are linear in a plan view are formed at a predetermined formation pitch (lattice pattern). Although the example provided with the diffraction grating panels 13, 13A, 13B (13c, 13Ac, 13Bc) configured to function as the diffraction grating 30 is described, the “diffraction grating” is not limited to this, and as an example, FIG. Like the diffraction grating 30a in the diffraction grating panel 13d shown in Fig. 39, it is 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. A configuration in which an uneven pattern (grating pattern) is formed to function as a “diffraction grating” can be employed. In both figures, as an example, the center of the convex portion in the width direction (phase-type diffraction grating) or the portion corresponding to the top of the convex portion (blazed diffraction grating) is shown by a solid line (curve). Yes.

  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.

  In addition, 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. 39, 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. , 13A, 13B (13c, 13Ac, 13Bc), light L2 (L2R, L2G, L2B) from the optical path changing panel 12 (12c) or light L1 (L1R, L1G from the light source 3 (3C) , L1B) can be diffracted and emitted in any 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 a phase type diffraction grating 30. Then, the light L2 (L2R, L2G, L2B) from the optical path changing panel 12 (12c) or the light L1 (L1R, L1G, L1B) from the light source 3 (3C) is diffracted in a predetermined direction. The display device 2, 2A (2C, 2AC) having the diffraction grating panel 13, 13A (13c, 13Ac) and the display device 1, 1A (1C, 1AC) configured as described above are described as examples. In place of 13, 13A (13c, 13Ac), the light L2 (from the optical path changing panel 12 (12c) can be obtained by any of the diffraction grating panels 13e to 13g shown in FIGS. 2R, may L2G, L2B), or, the light L1 from the light source 3 (3C) (L1R, L1G, also be configured to diffract a predefined direction L1B).

  In this case, the diffraction grating panels 13e to 13g are replaced with a plurality of convex portions 31a and a plurality of convex portions 31a and 13A instead of the grating pattern (concave / convex pattern) formed of the convex portions 31 and the concave portions 32 in the diffraction grating panels 13, 13A (13c, 13Ac). Of the light source L2 (L2R, L2G, L2B) from the optical path changing panel 12 (12c), or the grating pattern functions as the phase type diffraction grating 30b. The light L1 (L1R, L1G, L1B) from the light source 3 (3C) is diffracted in a predetermined direction. In the diffraction grating panels 13e to 13g, the same elements as those of the diffraction grating panels 13 and 13A (13c and 13Ac) described above are denoted by the same reference numerals and redundant description is omitted.

  In this case, as shown in FIGS. 40 and 41, 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. 42, in the diffraction grating 30b of the diffraction grating panel 13g, the extending direction of the convex portion 31a (the direction of the solid line La in FIG. 42) is obliquely intersected with 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 13A (13Ac) where δy ≠ 0 °.

  Also, the light L2 (L2R, L2G, L2B) from the optical path changing panel 12 (12c) or the light L1 (L1R) from the light source 3 (3C) by any of the diffraction grating panels 13h to 13j shown in FIGS. , L1G, L1B) can be configured to diffract in a predetermined direction. In this case, the diffraction grating panels 13h to 13j are 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 panels 13 and 13A (13c and 13Ac) described above. A grating pattern composed of a plurality of high refractive index portions 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 phase type diffraction grating 30c, so that the optical path The light L2 (L2R, L2G, L2B) from the change panel 12 (12c) or the light L1 (L1R, L1G, L1B) from the light source 3 (3C) is diffracted in a predetermined direction. Yes.

  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 a “light diffraction section” similar to the diffraction grating panels 13, 13A, 13a, 13b, 13e to 13f described above.

  Furthermore, the display devices 2C, 2AC, and 2BC (display devices 1C, 1AC, and 1BC) configured to display RGB color images have been described as examples. However, various color images other than RGB color images can be displayed. A “display” and a “display device” can also be configured. In the case of adopting such a configuration, the above “d”, “ε”, and the like 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”.

  In addition, the display 2, 2 </ b> A, 2 </ b> B (2 </ b> C, 2 </ b> AC, 2 </ b> BC) configured with the diffusion plate 14 has been described as an example, but in addition to the “light diffusion portion (diffusion plate 14)”, “light diffusion” The “display” can also be configured by arranging a “protection plate” for preventing scratches on the portion or the like and adhesion of dust, a “decorative plate” subjected to non-glare processing, and the like.

1, 1A, 1B, 1C, 1AC, 1BC Display device 2, 2A, 2B, 2C, 2AC, 2BC Display 3, 3C Light source 4 Control unit 10, 10R, 10G, 10B Light emitting unit 12, 12c Optical path changing panel 13 , 13A, 13B, 13a to 13k, 13Ac, 13Bc Diffraction grating panel 14 Diffusion plate 20, 20R, 20G, 20B, 200 Prism 30, 30R, 30G, 30B, 30a to 30c Diffraction grating F1, F2, F4 Panel surface F3 Diffraction Lattice surface L1-L4, L1R-L4R, L1G-L4G, L1B-L4B Light

Claims (4)

A display device having a light diffraction section for diffracting light from a light source,
N types of images can be displayed so that different images can be seen from N viewpoints (N is a natural number of 4 or more) facing the display and different in the left-right direction of the display. Configured,
The light diffracting unit is configured so that a diffraction grating is formed for each display pixel and diffracts light from the light source in each of the diffraction gratings in a predetermined direction, and is directed toward the display. The viewpoint position at the Mth position from the left side (M is a natural number obtained by rounding up the value obtained by dividing N by 3) is defined as the first viewpoint position, and the Mth viewpoint from the right side toward the display. Two diffraction gratings formed respectively corresponding to the two display pixels located at the same position in the two types of images viewed at the viewpoint positions adjacent to each other in the left-right direction with the position as the second viewpoint position An angular difference P between the respective perist rotation angles of the two diffraction gratings in the diffraction grating set consisting of: and an average value of the angular differences P of the (N-1) sets of diffraction grating sets. 1st average value The (N-2M + 2) types of the images that are visually recognized at (N-2M + 2) locations from the first viewpoint position to the second viewpoint position in the left-right direction. At least one of the (N−2M + 2−1) diffraction grating sets each including (N−2M + 2) diffraction gratings respectively formed corresponding to the display pixels located at least. The display device is configured such that the angle difference P is smaller than the first average value. A display that includes a light diffracting unit that diffracts light from a light source and that can display one display pixel in one image with a plurality of types of colored light having different wavelengths,
N types of the images can be displayed so that the images different from each other can be viewed from each of N viewpoints (N is a natural number of 4 or more) facing the display and differing in the horizontal direction of the display. Composed of
The light diffracting unit is configured such that a diffraction grating is formed corresponding to each color light for displaying the one display pixel, and each color light is diffracted in a predetermined direction for each diffraction grating. At the same time, the viewpoint position at the Mth position (M is a natural number obtained by rounding up a fraction of a value obtained by dividing N by 3) from the left side toward the display is defined as the first viewpoint position, and the display is directed to the display. The second viewpoint position is the Mth viewpoint position from the right side, and the same of two display pixels located at the same position in the two types of images viewed at the viewpoint positions adjacent in the left-right direction. An angle difference P is defined as an angle difference P of each of the two diffraction gratings in the diffraction grating set including the two diffraction gratings respectively formed corresponding to the color lights of color, and (N−1) Pair of said times When the average value of the angle differences P of each lattice set is the first average value, the (N−2M + 2) locations in the left-right direction from the first viewpoint position to the second viewpoint position In each of the (N−2M + 2) types of images visually recognized at the viewpoint position, the (N−2M + 2) diffractions respectively formed corresponding to the same color light of the display pixels located at the same position. A display configured such that the angle difference P of at least one of the (N-2M + 2-1) sets of diffraction gratings made of a grating is smaller than the first average value. vessel.   When the average value of the angle difference P of each of the (N−2M + 2-1) sets of diffraction gratings is set as a second average value, the light diffraction unit has the second average value as the first value. The display according to claim 1 or 2, wherein the display is configured to be smaller than an average value of 1.   4. 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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