Three-dimensional image display device

Abstract

To provide a three-dimensional image display device capable of switching a portrait / landscape mode with a simplified configuration.SOLUTION: A three-dimensional image display device 1 includes: an original image generation section; an element image group generation section; an element image group output section; and a three-dimensional image display section 10. The three-dimensional image display section 10 includes an element image group display section 20 for displaying an element image group and a high-function lenticular lens 30 on which emission light of the element image group display section 20 impinges. The element image group display section 20 is constituted of a pixel with right circularly polarized light as emission light and a pixel with left circularly polarized light as emission light. The high-function lenticular lens 30 functions as a lenticular lens with a period in either a first direction or a second direction according to a rotation direction of incident circularly polarized light. The element image group output section switches an element image group with parallax in the first direction and an element image group with parallax in the second direction and outputs it to the three-dimensional image display section 10 on the basis of the direction of the three-dimensional image display section 10.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a three-dimensional image display device. [Background technology]

[0002] Conventionally, the parallax barrier method and the lenticular lens method are known as high-resolution naked-eye 3D image display methods that utilize the parallax between the two eyes. The parallax barrier method and the lenticular lens method are 3D image display methods that present parallax in the horizontal direction. The parallax barrier method places a light-shielding slit in front of a display device such as a liquid crystal display (LCD), and the lenticular lens method places a lenticular lens with cylindrical lenses arranged in one direction in front of the display device, and can present different images to the left and right eyes. However, these methods do not allow switching between portrait mode, which is a vertically long display, and landscape mode, which is a horizontally long display (hereinafter referred to as portrait / landscape display switching), as is done on the screens of smartphone terminals and tablet terminals, for example. To enable this vertical / horizontal display switching, Patent Document 1 proposes a method using a liquid crystal parallax barrier, and Patent Document 2 proposes a method using a liquid crystal lenticular lens. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-119634 A [Patent Document 2] JP 2012-198435 A [Non-patent literature]

[0004] [Non-Patent Document 1] J. Kim, Y. Li, MN Miskiewicz, C. Oh, MW Kudenov, and MJ Escuti, “Fabrication of ideal geometric-phase holograms with arbitrary wavefronts,” Optica, Vol. 2, No. 11, pp. 958-964 (2015) [Non-Patent Document 2] C. van Berkel and JA Clarke, “Characterization and optimization of 3D-LCD module design,” Proc. Of SPIE, Vol. 3012, pp. 179-187 (1997) Summary of the Invention [Problem to be solved by the invention]

[0005] Liquid crystal parallax barriers and liquid crystal lenticular lenses are liquid crystal elements that are driven by applying voltage, and require components such as electrodes and driving circuits for driving, which creates the problem of making the structure of 3D image display devices complicated. An object of the present invention is to provide a three-dimensional image display device that is capable of switching between portrait and landscape modes with a simplified configuration, without the need for a liquid crystal parallax barrier or a liquid crystal lenticular lens. [Means for solving the problem]

[0006] A three-dimensional video display device according to an embodiment is a three-dimensional video display device that uses an element image group having parallax in a first direction and an element image group having parallax in a second direction perpendicular to the first direction, and includes an original image generation unit that generates an original image used to generate the element image group, an element image group generation unit that generates the element image group, an element image group output unit that outputs the generated element image group, and a three-dimensional video display unit that displays a three-dimensional video using the element image group. The three-dimensional video display unit includes an element image group display unit that displays the element image group, and an element image group output unit that outputs the generated element image group. The present invention is characterized in that it has a high-performance lenticular lens onto which output light is incident, the elemental image group display unit is composed of pixels that output right-handed circularly polarized light and pixels that output left-handed circularly polarized light, the high-performance lenticular lens functions as a lenticular lens having a period in either the first direction or the second direction depending on the rotation direction of the incident circularly polarized light, and the elemental image group output unit switches between an elemental image group having parallax in the first direction and an elemental image group having parallax in the second direction based on the orientation of the 3D video display unit, and outputs them to the 3D video display unit. Effect of the Invention

[0007] According to the present invention, it is possible to provide a three-dimensional image display device capable of switching between portrait and landscape modes with a simplified configuration. [Brief description of the drawings]

[0008] [Figure 1A] 1 is a front view illustrating an outline of a three-dimensional image display device according to an embodiment. [Figure 1B] 1 is a front view illustrating an outline of a three-dimensional image display device according to an embodiment. [Diagram 2] 1 is a side view illustrating an outline of a three-dimensional image display unit according to an embodiment. [Figure 3A] 2 is a front view illustrating an outline of an elemental image group display unit according to the embodiment; FIG. [Figure 3B] 2 is a front view illustrating an outline of an elemental image group display unit according to the embodiment; FIG. [Figure 4A]1 is a front view illustrating an outline of a patterned optical film of an elemental image group display portion according to an embodiment; [Figure 4B] 1 is a front view illustrating an outline of a patterned optical film of an elemental image group display portion according to an embodiment; [Figure 5A] 1 is a side view illustrating an outline of a high-performance lenticular lens according to an embodiment; [Figure 5B] 1 is an exploded perspective view illustrating an outline of a high-performance lenticular lens according to an embodiment; [Figure 6A] 1 is a top view illustrating an outline of incident light and exit light of a high-performance lenticular lens according to an embodiment; [Figure 6B] 1 is a side view illustrating an outline of incident light and exit light of a high-performance lenticular lens according to an embodiment; [Figure 7A] 1 is a top view illustrating an outline of incident light and exit light of a high-performance lenticular lens according to an embodiment; [Figure 7B] 1 is a side view illustrating an outline of incident light and exit light of a high-performance lenticular lens according to an embodiment; [Figure 8] 1 is a block diagram illustrating an outline of a three-dimensional image display device according to a first embodiment. [Figure 9] 13 is a side view illustrating an outline of a high-performance lenticular lens according to a modified example. FIG. [Figure 10] FIG. 13 is a block diagram illustrating an outline of a control unit according to a second embodiment; [Figure 11] FIG. 11 is a top view illustrating an example of viewpoint numbers and viewpoint directions. [Figure 12] 1 is a top view illustrating a virtual camera and a common imaging plane in generating a horizontal multi-view image. [Figure 13A] 13 is a top view illustrating the positional relationship between a pattern image and a multi-directional image in the second embodiment. FIG. [Figure 13B] 13 is a side view illustrating the positional relationship between a pattern image and a multidirectional image in the second embodiment. FIG. [Figure 14] 13 is a flowchart illustrating a flow of a generation process of an elemental image group in a control unit of a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [First embodiment] A 3D image display device 1 according to a first embodiment will be described with reference to Fig. 1A to Fig. 8. The 3D image display device 1 is a device capable of displaying 3D images that present parallax in the horizontal direction, which is the direction in which both eyes are aligned. As illustrated in Fig. 1A and Fig. 1B, the three-dimensional image display device 1 includes a three-dimensional image display section 10. Fig. 1A and Fig. 1B are views of the three-dimensional image display device 1 as seen from the front, and the three-dimensional image display section 10 is observed from the outside as a screen 15 on which a three-dimensional image is displayed. Here, the screen 15 is rectangular having long and short sides. The direction of the short side of the screen 15 is defined as a first direction D1, and the direction of the long side is defined as a second direction D2. The second direction D2 is perpendicular to the first direction D1.

[0010] The 3D image display device 1 has a function of switching between portrait and landscape display. As shown in Fig. 1A, in portrait mode, which is a vertically long display, the orientation of the 3D image display unit 10 with respect to the observer watching the screen 15 is vertical, and the 3D image is displayed so that the short side of the screen 15 is horizontal. On the other hand, as shown in Fig. 1B, in landscape mode, which is a horizontally long display, the orientation of the 3D image display unit 10 with respect to the observer is horizontal, and the 3D image is displayed so that the long side of the screen 15 is horizontal. The three-dimensional image display device 1 displays three-dimensional images using an element image group having parallax in a first direction D1 and an element image group having parallax in a second direction D2. Here, the element image group having parallax in the first direction D1 is used in portrait mode, and the element image group having parallax in the second direction D2 is used in landscape mode. The element image group is a set of element images that are images corresponding to individual element lenses of a high-performance lenticular lens, and includes element images in the same number as the number of element lenses. In addition, in the parallax presentation direction, each element image includes pixels in the same number as the viewpoint. The element image group having parallax in the first direction (second direction) refers to an element image group having an image for presenting parallax in the first direction (second direction). The element image group is displayed on an element image group display unit described later.

[0011] In the following, the horizontal direction in the observer's space is defined as the x-direction, and the direction from left to right is defined as positive. The direction parallel to screen 15 and perpendicular to the horizontal direction is defined as the y-direction, and the direction from top to bottom is defined as positive. The direction perpendicular to screen 15 is defined as the z-direction, and the direction from 3D image display unit 10 toward the observer is defined as positive. In the following description, unless otherwise specified, the three-dimensional image display device 1 will be described as being in portrait mode (vertical display).

[0012] (3D image display section) The three-dimensional image display unit 10 is a device capable of presenting different images depending on the line of sight. The three-dimensional image display unit 10 displays three-dimensional images using an elemental image group output from an elemental image group output unit of a control unit, which will be described later. As illustrated in Fig. 2, the three-dimensional video display unit 10 has an elemental image group display unit 20 that displays an elemental image group, and a high-performance lenticular lens 30 into which light emitted from the elemental image group display unit 20 is incident. Here, the three-dimensional video display unit 10 further has a spacer 12. Note that Fig. 2 is a side view illustrating the three-dimensional video display unit 10. The three-dimensional video display unit 10 will be described below, and then the configuration other than the three-dimensional video display unit 10 will be described.

[0013] (Elemental image group display section) The elemental image group display unit 20 is a planar element that displays an elemental image group. As illustrated in Fig. 3A and Fig. 3B, the elemental image group display unit 20 is composed of a pixel 25R that outputs right-handed circularly polarized light and a pixel 25L that outputs left-handed circularly polarized light. The elemental image group display unit 20 has a display device 21 and a patterned optical film 23. The display device 21 can be a direct-view type display device such as a liquid crystal display or an organic electroluminescence display, and a general direct-view type display device such as a smartphone terminal or a tablet terminal can be used as it is.

[0014] The patterning optical film 23 is a film-like member that controls the polarization state of light passing through it. The patterning optical film 23 covers the emission surface of the display device 21 and is disposed in close contact with the display device 21 with no gaps. The display device 21 and the patterning optical film 23 are each partitioned to correspond to the pixels of the elemental image group display section 20. The light emitted from the display device 21 passes through the patterning optical film 23 and becomes the light emitted from the elemental image group display section 20 in which the rotation direction of circularly polarized light is set for each pixel.

[0015] 3A and 3B, the elemental image group display unit 20 has pixels 25 aligned in a first direction D1 and a second direction D2 perpendicular to the first direction D1, and each pixel 25 emits either right-handed circularly polarized light or left-handed circularly polarized light to display the elemental image group. Here, whether the emitted light from each pixel 25 is right-handed circularly polarized light or left-handed circularly polarized light is set in advance and stored in the storage unit 50. Note that FIGS. 3A and 3B are front views illustrating the elemental image group display unit 20, and also illustrate the polarization state of the emitted light from the pixels 25. It is preferable that half of the pixels 25 in the elemental image group display section 20 are pixels 25R that emit right-handed circularly polarized light, and the remaining half are pixels 25L that emit left-handed circularly polarized light. The pixels 25 in the elemental image group display section 20 have the same pixel pitch (pixel size) and number of pixels as the pixels in the display device 21. Note that one pixel in the display device 21 is a set of sub-pixels of red, green, and blue (RGB), for example, and the elemental image group display section 20 can display a full-color elemental image group.

[0016] As shown in FIG. 3A, the right-handed and left-handed circularly polarized pixels 25 may be arranged in a line-by-line manner in which rows of right-handed circularly polarized pixels 25R and rows of left-handed circularly polarized pixels 25L are arranged alternately. Alternatively, as shown in FIG. 3B, the pixels 25 may be arranged in a staggered manner in the row and column directions so that the pixels 25 are not aligned in the same direction of rotation. The arrangement of the right-handed and left-handed circularly polarized pixels 25 is not particularly limited, but an arrangement with little bias is preferable. An arrangement with little bias is, for example, an arrangement in which the ratio of the number of right-handed circularly polarized pixels 25R to the number of left-handed circularly polarized pixels 25L in 16 pixels 25 arranged in 4 rows and 4 columns is in the range of 4:6 to 6:4. Note that right-handed circularly polarized light refers to a state in which the electric field vector rotates clockwise when viewed in the direction of light travel from the light source, and left-handed circularly polarized light refers to a state in which the electric field vector rotates counterclockwise. Also, the right-handed circularly polarized pixel 25R is used to display 3D images in portrait mode (vertical display), and the left-handed circularly polarized pixel 25L is used to display 3D images in landscape mode (horizontal display).

[0017] Here, the configuration of the patterned optical film 23 will be described using the line-by-line method as an example. When the light emitted from the display device 21 is linearly polarized light, the patterned optical film 23 is composed of a quarter-wave plate, and the inclination of the fast axis of the quarter-wave plate is made different for each line. If the light emitted from the display device 21 is linearly polarized light whose electric field oscillates in the x-direction, as illustrated in FIG. 4A, the fast axis of the quarter-wave plate corresponding to the odd lines OL is inclined 45 degrees counterclockwise with respect to the x-axis as viewed from the observer side, and the fast axis of the even lines EL is inclined 45 degrees clockwise, thereby forming an elemental image group display section 20 in which right-handed circularly polarized pixels 25R are arranged on the odd lines OL and left-handed circularly polarized pixels 25L are arranged on the even lines EL in a line-by-line manner. Note that FIGS. 4A and 4B are front views of the patterned optical film 23. In addition, the odd-numbered lines OL are the lines that are odd-numbered when the top row as seen by the observer is numbered 1, and numbers are assigned downward as 2, 3, ..., and the even-numbered lines EL are the lines that are even-numbered.

[0018] If the light emitted from the display device 21 is linearly polarized light whose electric field oscillates in the y direction, then the fast axis of the quarter-wave plate corresponding to the odd lines OL can be tilted 45 degrees clockwise with respect to the x-axis when viewed from the observer's side, and the fast axis of the even lines EL can be tilted 45 degrees counterclockwise to create an elemental image group display unit 20 in which right-handed circularly polarized pixels 25R are arranged for the odd lines OL and left-handed circularly polarized pixels 25L are arranged for the even lines EL in a line-by-line manner. In the case where the light emitted from the display device 21 is randomly polarized, a linear polarizing plate is placed between the display device 21 and the patterning optical film 23 to make the light emitted from the display device 21 linearly polarized, and the patterning optical film 23 is constructed from a 1 / 4 wavelength plate.

[0019] On the other hand, when the light emitted from the display device 21 is right-handed circularly polarized light, the patterned optical film 23 may be configured so that the region corresponding to the even lines EL acts as a half-wave plate and the odd lines OL do not act as a wave plate, as illustrated in Fig. 4B. When the light emitted from the display device 21 is left-handed circularly polarized light, the region corresponding to the odd lines OL is made into a half-wave plate and the even lines EL do not act as a wave plate.

[0020] (High-performance lenticular lens) The high-performance lenticular lens 30 is a lens that changes the direction in which it functions as a lenticular lens depending on the rotation direction of the incident circularly polarized light. The light emitted from the elemental image group display unit 20 is incident on the high-performance lenticular lens 30. The high-performance lenticular lens 30 is disposed at a focal length f away from the elemental image group display unit 20 so as to cover the display surface on which the pixels of the elemental image group display unit 20 are arranged.

[0021] The high-performance lenticular lens 30 functions as a lenticular lens having a period in either the first direction D1 or the second direction D2 depending on the rotation direction of the incident circularly polarized light. Here, when the rotation direction of the incident circularly polarized light is right, i.e., when the incident light is right-handed circularly polarized light, the high-performance lenticular lens 30 functions as a lenticular lens having a period in the first direction D1. On the other hand, when the rotation direction of the incident circularly polarized light is left, i.e., when the incident light is left-handed circularly polarized light, the high-performance lenticular lens 30 functions as a lenticular lens having a period in the second direction D2. The high-performance lenticular lens 30 can function as a lenticular lens having a period in the first direction D1, for example, by selecting and displaying the right-handed circularly polarized pixels 25R in the element image group display unit 20 and setting the pixel value of the left-handed circularly polarized pixels 25L to 0. Note that having a period in a certain direction means that element lenses of the same shape are lined up in that direction. The element lenses are individual lenses arranged in a lenticular lens or a lens array. For example, in a typical lenticular lens, plano-convex cylindrical lenses are lined up in a direction with a period.

[0022] As illustrated in Figures 5A and 5B, the high-performance lenticular lens 30 can be formed by overlapping a first polarizing diffractive lens 31 in which element lenses 31E are arranged in a first direction D1, a second polarizing diffractive lens 32 in which element lenses 32E are arranged in a second direction D2, and a lens array 33 in which convex lenses are arranged in the first direction D1 and the second direction D2. Note that Figure 5A is a side view of the high-performance lenticular lens 30, and Figure 5B is a perspective view of an exploded view of a portion in which eight element lenses 31E and 32E are arranged. The element lenses 31E and 32E can be lenses that function as cylindrical lenses. The lens array 33 has element lenses 33E arranged in the first direction D1 and the second direction D2. The element lenses 33E may be plano-convex spherical lenses.

[0023] The first polarizing diffractive lens 31 and the lens array 33 have the same lens pitch in the first direction D1, and the second polarizing diffractive lens 32 and the lens array 33 have the same lens pitch in the second direction D2. The element lenses 33E of the lens array 33 are aligned with the element lenses 31E in the first direction D1, and aligned with the element lenses 32E in the second direction D2. The lens pitch is the width of the element lenses in the direction in which the lenses are arranged. When corresponding element lenses are aligned, the lens pitches are said to be equal or aligned.

[0024] The first polarizing diffractive lens 31 and the second polarizing diffractive lens 32 have the same absolute value of the focal length, and the sign of the focal length is reversed between right-handed circularly polarized incident light and left-handed circularly polarized incident light. That is, the first polarizing diffractive lens 31 and the second polarizing diffractive lens 32 switch the positive and negative focal lengths of the element lenses 31E and 32E depending on the rotation direction of the incident circularly polarized light. Then, they switch between a state where they function as a lenticular lens composed of convex element lenses and a state where they function as a lenticular lens composed of concave element lenses. 5B, the first polarizing diffractive lens 31 functions as a lenticular lens with a period in the x direction, and the second polarizing diffractive lens 32 functions as a lenticular lens with a period in the y direction. Furthermore, element lenses 31E and 32E function as a convex lens with a focal length of a when right-handed circularly polarized light is incident, and as a concave lens with a focal length of -a when left-handed circularly polarized light is incident.

[0025] Furthermore, the first polarizing diffractive lens 31 and the second polarizing diffractive lens 32 have opposite rotation directions of circularly polarized light between incident light and outgoing light. That is, when right-handed circularly polarized light is incident, the outgoing light becomes left-handed circularly polarized light, and when left-handed circularly polarized light is incident, the outgoing light becomes right-handed circularly polarized light. Furthermore, the absolute values ​​of the focal lengths of the first polarizing diffractive lens 31 and the second polarizing diffractive lens 32 are set to be the same as the focal length of the lens array 33. That is, the absolute values ​​of the focal lengths of the first polarizing diffractive lens 31, the second polarizing diffractive lens 32, and the lens array 33 are the same. For example, when the focal lengths of the first polarizing diffractive lens 31 and the second polarizing diffractive lens 32 are ±a, the focal length of the lens array 33 is set to a.

[0026] Here, the point that the direction in which the high-performance lenticular lens 30 functions as a lenticular lens is switched depending on the rotation direction of the circularly polarized light of the incident light will be described with reference to Figures 5A to 7B. The incident light is assumed to be a parallel light of circular polarization. The focal length of the first polarizing diffractive lens 31 is f1, the focal length of the second polarizing diffractive lens 32 is f2, the focal length of the lens array 33 is f3, and the focal length of the high-performance lenticular lens 30 is f. FIG. 6A illustrates the outgoing light in a top view when the incident light is right-handed circularly polarized light. First, when right-handed circularly polarized light is incident on the first polarizing diffractive lens 31, the element lens 31E acts as a convex lens with a focal length of f1=a. As illustrated in FIG. 5A, the incident light is incident on the first polarizing diffractive lens 31. The second polarizing diffractive lens 32 does not bend the light in the x direction. The lens array 33 is a convex lens with a focal length of f3=a. Therefore, the high-performance lenticular lens 30 is a composite lens of the first polarizing diffractive lens 31 and the lens array 33, and functions as a lenticular lens with a positive focal length of f=a / 2. The element lens 30E of the high-performance lenticular lens 30 has a structure in which the first polarizing diffractive lens 31, the second polarizing diffractive lens 32, and the lens array 33 are overlapped.

[0027] FIG. 6B illustrates the exiting light in a side view when the incident light is right-handed circularly polarized. The first polarizing diffractive lens 31 does not bend light in the y direction. However, the first polarizing diffractive lens 31 exits left-handed circularly polarized light with the opposite rotation direction. The second polarizing diffractive lens 32 receives left-handed circularly polarized light, and the element lens 32E acts as a concave lens with a focal length f2=-a. The lens array 33 is a convex lens with a focal length f3=a. As a result, the lens effects are offset, and the high-performance lenticular lens 30 transmits light like a glass plate. 7A illustrates the outgoing light in a top view when the incident light is left-handed circularly polarized light. First, when left-handed circularly polarized light is incident on the first polarizing diffractive lens 31, the element lens 31E acts as a concave lens with a focal length of f1=-a. The second polarizing diffractive lens 32 does not bend the light in the x-direction. The lens array 33 is a convex lens with a focal length of f3=a. Therefore, the lens actions are offset, and the high-performance lenticular lens 30 transmits light like a glass plate.

[0028] FIG. 7B illustrates the outgoing light in a side view when the incident light is left-handed circularly polarized light. The first polarizing diffractive lens 31 does not bend light in the y direction. However, the first polarizing diffractive lens 31 outputs right-handed circularly polarized light with the rotation direction reversed. The second polarizing diffractive lens 32 receives right-handed circularly polarized light, and the element lens 32E acts as a convex lens with a focal length f2=a. The lens array 33 is a convex lens with a focal length f3=a. Therefore, the high-performance lenticular lens 30 becomes a composite lens of the second polarizing diffractive lens 32 and the lens array 33, and functions as a lenticular lens with a positive focal length f=a / 2. In this way, the high-performance lenticular lens 30 switches between a state in which it functions as a lenticular lens with periodicity in the x direction and a state in which it functions as a lenticular lens with periodicity in the y direction, depending on the rotation direction of the circularly polarized light that is incident on it.

[0029] The first polarizing diffractive lens 31 and the second polarizing diffractive lens 32 can be, for example, polarizing diffractive elements made of periodically oriented liquid crystal polymers, and can be manufactured by conventional technology (Non-Patent Document 1). The liquid crystal polymer has a thickness of about several μm, and can be manufactured to be thin. The lens array 33 can be a general convex lens array or a diffractive lens array. 5A, the first polarizing diffractive lens 31, the second polarizing diffractive lens 32, and the lens array 33 are arranged in close contact with each other. The high-performance lenticular lens 30 can be manufactured by separately producing the first polarizing diffractive lens 31, the second polarizing diffractive lens 32, and the lens array 33, and bonding them together using an adhesive material.

[0030] (Spacer) The spacer 12 is a member that separates the display device 21 and the high-performance lenticular lens 30 by a predetermined distance. As exemplified in Fig. 2, the spacer 12 is disposed between the elemental image group display section 20 and the high-performance lenticular lens 30. Here, the predetermined distance is the focal length f of the high-performance lenticular lens 30. By separating them by the focal length f, it is possible to make the light emitted from the high-performance lenticular lens 30 into parallel light. The spacer 12 is a transmissive spacer, and a glass plate, an acrylic plate, or the like can be used.

[0031] Next, the configuration of the three-dimensional image display device 1 other than the three-dimensional image display unit 10 will be described. As illustrated in Fig. 8, the three-dimensional image display device 1 includes, in addition to the three-dimensional image display unit 10, a control unit 40 that performs calculations such as generating elemental image groups. Here, the three-dimensional image display device 1 further includes a storage unit 50 and an attitude detection unit 60. Each of these components will be described below.

[0032] (Control unit) The control unit 40 performs calculations to generate an elemental image group from externally input 3D scene data in accordance with the specification values ​​of the 3D video display unit 10. In addition, the control unit 40 outputs the elemental image group to the 3D video display unit 10 so as to be in portrait mode or landscape mode. The control unit 40 includes an original image generation unit 41, an elemental image group generation unit 42, and an elemental image group output unit 46.

[0033] (Original image generation unit) The original image generating unit 41 is a means for generating an original image used to generate the element image group. The original image generating unit 41 generates and outputs, as original images, a multi-viewpoint image corresponding to the number of viewpoints of the 3D video from the input 3D scene data. As the 3D scene data, general 3D data composed of polygons or point clouds (3D point clouds) can be used. The multi-viewpoint image is a set of images with different viewpoints. The number of viewpoints of the 3D video is the same as the number of pixels of the pixels 25 of the element image group display unit 20 corresponding to the element lenses 31E and 32E of the high-performance lenticular lens 30. For example, if the lens pitch of the high-performance lenticular lens 30 is 500 μm and the pixel pitch of the pixels 25 of the element image group display unit 20 is 25 μm, the original image generating unit 41 generates 20 viewpoints in the horizontal direction, that is, 20 original images.

[0034] (Elemental image group generation unit) The element image group generating unit 42 is a means for generating an element image group. The element image group generating unit 42 performs an element image group generation process for generating an element image group in, for example, a portrait mode as one image from an input original image, and sends the element image group to the element image group output unit 46. This element image group generation process can be performed in the same manner as the image generation process performed in a conventional general lenticular lens type three-dimensional image display device. However, unlike conventional techniques, the element image group is displayed only with the corresponding pixels 25 depending on whether the element image group is in portrait mode or landscape mode. For example, when displaying a 3D image in portrait mode, the element image group is displayed only with pixels for portrait mode, and the pixel values ​​of the pixels for landscape mode are set to 0. Here, the pixels for portrait mode are right-handed circularly polarized pixels, and the pixels for landscape mode are left-handed circularly polarized pixels. The element image group generator 42 generates two types of element image groups, an element image group having parallax in the first direction and an element image group having parallax in the second direction, from the original image.

[0035] The element image group generation unit 42 generates an element image group by setting the pixel value of one of the right-handed circularly polarized pixels and the left-handed circularly polarized pixels of the element image group display unit 20 to 0 so as to display an element image group having parallax in the first direction. Here, the element image group having parallax in the first direction is an element image group in portrait mode. The element image group generation unit 42 generates an element image group by setting the pixel value of the left-handed circularly polarized pixels to 0 so as to display an element image group having parallax in the first direction using right-handed circularly polarized pixels. Furthermore, the element image group generation unit 42 generates an element image group by setting the pixel value of one of the right-handed circularly polarized pixels and the left-handed circularly polarized pixels of the element image group display unit 20 to 0, and using the other to display an element image group having parallax in the second direction. Here, the element image group having parallax in the second direction is an element image group in landscape mode. The element image group generation unit 42 generates an element image group by setting the pixel value of the right-handed circularly polarized pixels to 0, and using the left-handed circularly polarized pixels to display an element image group having parallax in the second direction.

[0036] (Element image group output section) The elemental image group output unit 46 is a means for outputting the generated elemental image group. Based on the orientation of the 3D video display unit 10, the elemental image group output unit 46 switches between an elemental image group having parallax in the first direction and an elemental image group having parallax in the second direction and outputs the switched elemental image group to the 3D video display unit 10. The element image group generation unit 42 generates two types of element image groups, an element image group having parallax in a first direction which is an element image group in portrait mode, and an element image group having parallax in a second direction which is an element image group in landscape mode, and sends them to the element image group output unit 46. Then, the element image group output unit 46 switches between the two types of element image groups based on the orientation of the 3D video display unit 10, i.e., whether it is portrait mode or landscape mode, and outputs them to the element image group display unit 20 of the 3D video display unit 10. Whether the mode is portrait mode or landscape mode can be specified from outside the control unit 40. Here, it is specified by an orientation detection signal from the orientation detection unit 60. The element image group output unit 46 can output an element image group having parallax in the horizontal direction to the element image group display unit 20 so that parallax can be presented in the horizontal direction.

[0037] (Storage part) The storage unit 50 is a means for storing the specification values ​​of the three-dimensional video display unit 10. The storage unit 50 stores information such as the number of pixels of the elemental image group display unit 20, the pixel pitch, the polarization state for each pixel, the lens pitch and focal length of the high-performance lenticular lens 30, and the positional relationship between the elemental image group display unit 20 and the high-performance lenticular lens 30, and can be used for generating original images and elemental image groups in the control unit 40. The storage unit 50 can also store the generated original images and elemental image groups.

[0038] (Posture detection section) The attitude detection unit 60 is a means for detecting the attitude of the 3D image display unit 10 and designating either the first direction D1 or the second direction D2 as the horizontal direction. The attitude detection unit 60 can detect the rotation angle when the normal direction of the plane on which the pixels 25 of the elemental image group display unit 20 are arranged is set as the rotation axis by a signal from an acceleration sensor or the like, and sends an attitude detection signal that designates either the first direction D1 or the second direction D2 as the horizontal direction to the control unit 40 based on the detection result. The attitude detection unit 60 may have an acceleration sensor or the like, and may use a signal from an acceleration sensor inside or outside the 3D image display device 1. Then, the element image group output unit 46 outputs the element image group having parallax in the first direction or the second direction specified in the horizontal direction. That is, the element image group output unit 46 outputs the element image group having parallax in the direction specified in the horizontal direction to the element image group display unit 20.

[0039] The 3D image display device 1 having the above configuration is composed of pixels that emit right-handed circularly polarized light and pixels that emit left-handed circularly polarized light, and is a combination of an element image group display unit 20 that emits either right-handed or left-handed circularly polarized light for each pixel, and a high-performance lenticular lens 30 that functions as a lenticular lens that has a period in a first direction when the incident light is right-handed circularly polarized light and has a period in a second direction when the incident light is left-handed circularly polarized light, thereby enabling portrait / landscape mode switching to be realized simply by switching the element image group displayed on the element image group display unit 20. Specifically, for example, when a 3D image in portrait mode is displayed, the element image group is displayed only by the right-handed circularly polarized pixels 25R of the element image group display unit 20, and the pixel value of the left-handed circularly polarized pixels 25L is set to 0. On the other hand, when a 3D image in landscape mode is displayed, the element image group is displayed only by the left-handed circularly polarized pixels 25L of the element image group display unit 20, and the pixel value of the right-handed circularly polarized pixels 25R is set to 0.

[0040] The high-performance lenticular lens 30 can be thinned by stacking the first polarizing diffractive lens 31, the second polarizing diffractive lens 32, and the lens array 33, which have the same lens pitch. The first polarizing diffractive lens 31 and the second polarizing diffractive lens 32 have the same focal length, and the signs of the focal lengths of the right-handed and left-handed circularly polarized incident light are inverted, and the rotation direction of the circularly polarized light is reversed between the incident light and the outgoing light. The first polarizing diffractive lens 31, the second polarizing diffractive lens 32, and the lens array 33 have the same absolute focal length, and therefore the lens can switch between a state where the lens functions as a lenticular lens having a period in the x direction and a state where the lens functions as a lenticular lens having a period in the y direction depending on the rotation direction of the circularly polarized light that is incident. This allows the three-dimensional image display device 1 to have a simple configuration that does not require a liquid crystal parallax barrier or a liquid crystal lenticular lens controlled by voltage application. The three-dimensional image display device 1 includes the orientation detection unit 60, and thus can switch between portrait and landscape modes by switching the element image group displayed on the element image group display unit 20 in accordance with the orientation detection result.

[0041] The three-dimensional image display device 1 can have the same functions and configuration as a general mobile terminal such as a smartphone terminal or a tablet terminal. That is, it can have a processor such as a central processing unit (CPU), a storage device including semiconductor memory such as ROM and RAM, an input interface (I / F), a communication I / F, a battery, an acceleration sensor, etc. The function of the control unit 40 can be performed by a processor, and the function of the storage unit 50 can be performed by a storage device. The attitude detection unit 60 can use a signal from an acceleration sensor, etc., provided in the three-dimensional image display device 1. Furthermore, the three-dimensional image display device 1 may be an independent display device, or may be incorporated in a mobile terminal. The direction of the long side of the screen may be the first direction. Also, if the screen is square, the direction of one of the sides can be the first direction.

[0042] Here, the operation of the three-dimensional image display device 1 will be described. First, the original image generating unit 41 of the control unit 40 generates an original image based on 3D scene data input from the outside. Next, the element image group generating unit 42 generates an element image group from the original image. At this time, the original image generating unit 41 and the element image group generating unit 42 refer to the specification values ​​such as the number of pixels and the lens pitch of the three-dimensional image display unit 10 in the storage unit 50. The element image group generating unit 42 generates two types of element image groups, portrait display and landscape display, from the original image and sends them to the element image group output unit 46. For example, the element image group for portrait display is generated only with pixels of right circular polarization, and the pixel value of the left circular polarization is set to 0. The attitude detection unit 60 detects the attitude of the three-dimensional image display unit 10 and sends an attitude detection signal specifying either portrait display or landscape display to the control unit 40. When portrait display is specified, the element image group output unit 46 outputs the element image group for portrait display to the element image group display unit 20.

[0043] Then, the elemental image group display unit 20 displays the elemental image group. The light emitted from the elemental image group display unit 20 is incident on the high-performance lenticular lens 30. The high-performance lenticular lens 30 is disposed at a distance of focal length f from the elemental image group display unit 20. Here, the right-handed circularly polarized incident light causes the high-performance lenticular lens 30 to become a lenticular lens having a period in the short side direction of the screen, and it is possible to present parallax in the short side direction of the screen. From this state, for example, if the screen is rotated 90 degrees and the orientation detection unit 60 specifies landscape display, the element image group output unit 46 switches the element image group in portrait display to an element image group in landscape display and outputs it to the element image group display unit 20. The three-dimensional image display device 1 can switch between vertical and horizontal display of three-dimensional images simply by switching the image data to be displayed on the pixels.

[0044] Next, an example of design values ​​of the 3D image display device 1 will be described. First, the number of pixels in the elemental image group display section 20 is 3000 × 4000 pixels, and the pixel pitch is 25 μm. The polarization state of the light emitted from the pixel 25 of the elemental image group display section 20 differs for each pixel based on the checker sampling method. The first polarizing diffractive lens 31 and the second polarizing diffractive lens 32 have a lens pitch of 500 μm and a focal length of ±2.84 mm. The lens array 33 has a lens pitch of 500 μm and a focal length of 2.84 mm. In this case, the lens pitch p L is 500 μm and the focal length f is 1.42 mm.

[0045] When the above design values ​​are used, the number of pixels and display size of the 3D image displayed by the 3D image display device 1 are 150 x 4000 pixels and 75 mm x 100 mm in portrait mode, and 200 x 3000 pixels and 100 mm x 75 mm in landscape mode. Note that these are expressed in x direction x y direction, with the x direction being the horizontal direction. Also, the viewing angle θ of the 3D image is V θ V =2tan -1 (p L / f), which is about 20 degrees horizontally. In this way, the number of pixels in the horizontal direction of a 3D image is smaller than that in the vertical direction. Conventionally, in a lenticular lens type 3D image display device, it is known that the balance between the number of pixels in the vertical direction of a 3D image and the number of viewpoints in the horizontal direction can be adjusted by slightly tilting the installation angle of the lenticular lens with respect to the display device. When it is desired to increase the number of viewpoints in the horizontal direction in exchange for lowering the vertical resolution of a 3D image, this conventional technology (Non-Patent Document 2) can be applied to the present invention.

[0046] (Modification) Next, a modified example of the high-performance lenticular lens will be described. As illustrated in FIG. 9, the high-performance lenticular lens 30A according to the modified example has a third polarizing diffractive lens 34 arranged instead of the lens array 33. The element lenses of the third polarizing diffractive lens 34 are arranged in the first direction D1 and the second direction D2, similar to the element lenses 33E of the lens array 33. In addition, a linear polarizing plate 35 and a quarter-wave plate 36 are arranged between the second polarizing diffractive lens 32 and the third polarizing diffractive lens 34. The third polarizing diffractive lens 34 has the same lens pitch as the first polarizing diffractive lens 31 and the second polarizing diffractive lens 32, similar to the lens array 33, and has the same absolute value of the focal length. The first polarizing diffractive lens 31 and the second polarizing diffractive lens 32 are the same as those of the high-performance lenticular lens 30.

[0047] Here, the third polarizing diffractive lens 34 is a polarizing diffractive element that functions as a convex lens array when right-handed circularly polarized light is incident thereon and as a concave lens array when left-handed circularly polarized light is incident thereon. The linear polarizing plate 35 and the quarter-wave plate 36 convert the light incident on the third polarizing diffractive lens 34 into right-handed circularly polarized light, causing the third polarizing diffractive lens 34 to function as a convex lens array. This modified example is optically equivalent to the high-performance lenticular lens 30 if the light utilization efficiency is not taken into consideration. The third polarizing diffractive lens 34, like the first polarizing diffractive lens 31 and the second polarizing diffractive lens 32, can be manufactured by conventional technology (Non-Patent Document 1).

[0048] In the high-performance lenticular lens 30A according to the modified example, the first polarizing diffractive lens 31, the second polarizing diffractive lens 32, and the third polarizing diffractive lens 34 can be manufactured using the same manufacturing equipment, so that manufacturing errors in lens pitch, focal length, and the like between these lenses can be reduced. This makes it possible to suppress the occurrence of stray light inside the high-performance lenticular lens. The decrease in transmittance caused by inserting the linear polarizing plate 35 can be compensated for by increasing the amount of light in the elemental image group display section 20.

[0049] [Second embodiment] Next, a 3D image display device according to a second embodiment will be described. The 3D image display device according to the second embodiment is different from the first embodiment in the control unit 40A, but the rest is the same. In the first embodiment, the elemental image group is generated by setting the pixel value of either the right-handed circularly polarized pixels or the left-handed circularly polarized pixels to 0. In contrast, in the second embodiment, the elemental image group is displayed using both the right-handed circularly polarized pixels and the left-handed circularly polarized pixels. The 3D image display device of the second embodiment additively combines a first pattern image and a second pattern image described below, and generates a group of element images based on optimization calculations so as to minimize the error between the 3D image displayed by the 3D image display unit and the original image.

[0050] As illustrated in Fig. 10, the control unit 40A has an original image generating unit 41A, an element image group generating unit 42A, a first pattern image generating unit 43, a second pattern image generating unit 44, a repeat execution unit 45, and an element image group output unit 46. The original image generating unit 41A generates an original image different from that of the first embodiment. The element image group generating unit 42A generates an element image group from a first pattern image and a second pattern image, not from an original image, different from that of the first embodiment. Each configuration of the control unit 40A will be described below. Note that, as in the first embodiment, the case of portrait mode (vertical display) will be described.

[0051] (Original image generation unit) The original image generating unit 41A generates and outputs, as original images, multi-viewpoint images corresponding to the number of viewpoints of the 3D video from the input 3D scene data.H , vertically N V and the original image is N H ×N V It is composed of multi-view images of different viewpoints. It should be noted that the lenticular lens method, which utilizes the parallax between the two eyes, does not present parallax in the vertical direction, but the number of viewpoints is set here for formality's sake.

[0052] The number of viewpoints in one direction is equal to the number of pixels in the elemental image group display section corresponding to one elemental lens of the high-performance lenticular lens. For example, when the lens pitch of the high-performance lenticular lens is 500 μm and the pixel pitch of the elemental image group display section is 25 μm, the number of viewpoints is 20 in both the horizontal and vertical directions. Here, s and t are the viewpoint numbers in the horizontal direction (x direction) and vertical direction (y direction), respectively. The viewpoint numbers are numbers assigned to each viewpoint. The viewpoint numbers s and t are integers or decimals. If the number of viewpoints in the horizontal direction is N, H , the number of viewpoints in the vertical direction is N V Let N H When is an odd number, the viewpoint number s is an integer in increments of 1 that satisfies formula (1).

number

number

[0053] Each pixel in the elemental image group display section can be assigned a viewpoint number. Specifically, among the pixels in the elemental image group display section corresponding to one elemental lens of the high-performance lenticular lens, the pixel with the lowest coordinate value in the x direction is assigned the highest viewpoint number (N H -1) / 2, the pixel with the highest coordinate value has the smallest viewpoint number -(N H -1) / 2 is assigned, and the pixels in between are assigned viewpoint numbers in increments of 1. The same is true for the y direction. Here, when pixel position m in the x direction in the element image group display area is input, the function that returns the viewpoint number assigned to the pixel at position m is defined as D x Similarly, let us define a function that returns the viewpoint number assigned to the pixel at position n when the pixel position n in the y direction is input as D y These functions will be used in the explanation of equations (8) and (9) below.

[0054] As illustrated in Figure 11, the direction of each viewpoint (viewpoint direction) is defined as the direction connecting the center position of each pixel 25 of the element image group display section 20 and the center position of the element lens 30E of the high-performance lenticular lens 30 corresponding to each pixel 25. 11 illustrates an example of the viewing direction in the xz plane when the high-performance lenticular lens 30 functions as a lenticular lens having a period in the x direction. One element lens 30E of the high-performance lenticular lens 30 corresponds to 20 pixels 25 of the elemental image group display unit 20. Spacers are not shown.

[0055] The viewpoint direction is the direction connecting the center position of each pixel 25 of the elemental image group display section 20 and the center position of the elemental lens 30E corresponding to each pixel 25. Since the number of pixels of the elemental image group display section 20 corresponding to one elemental lens 30E is equal to the number of viewpoints, the number of viewpoints is 20. Each viewpoint is assigned a viewpoint number in increments of 1. In the example of Fig. 11, the number of viewpoints is 20, which is an even number, so according to formula (2), the minimum viewpoint number is -9.5 and the maximum viewpoint number is 9.5. Fig. 11 shows three viewpoint directions with viewpoint numbers s = -9.5, 0.5, and 9.5.

[0056] In addition, the number of pixels and pixel pitch of each viewpoint image of the multi-viewpoint image are made the same as those of the elemental image group display unit, and the depth position (position in the z direction) of the display surface of the original image is made the same as the depth position of the high-performance lenticular lens surface. The original image generating unit 41A generates a multi-viewpoint image having parallax only in the horizontal direction from the 3D scene data. H Viewpoint, 1 vertical viewpoint, N in total HA multi-viewpoint image is generated for each viewpoint. Hereafter, this multi-viewpoint image is called a horizontal multi-viewpoint image. s Here, i and j are pixel positions in the x and y directions in the horizontal multi-viewpoint image, and correspond to the x and y coordinate values ​​on the high-performance lenticular lens surface that serves as the display surface. s (i,j) can be regarded as a function that returns the pixel value of a horizontal multi-viewpoint image when viewpoint number s and pixel position (i,j) are input.

[0057] Horizontal multi-view image V s A method of generating (i,j) will be described. As illustrated in FIG. 12, a horizontal multi-viewpoint image can be generated by placing a 3D model in a virtual space and photographing it from each viewpoint with a virtual camera VC. Assuming that there is a display surface DS (high-performance lenticular lens surface) of the three-dimensional image display unit 10 in the virtual space, this display surface DS is set as a common shooting surface to be photographed by the virtual camera VC. FIG. 12 illustrates an example of the positional relationship between the 3D model and the virtual camera VC when photographing an image corresponding to the viewpoint number s=-9.5 in FIG. 11. The 3D model is placed near the common shooting surface. The width (x direction) and height (y direction) of this common shooting surface are set to be equal to the width and height of the high-performance lenticular lens surface that becomes the display surface DS. The space including this common shooting surface is photographed by the virtual camera VC at a predetermined shooting angle corresponding to the viewpoint number s=-9.5.

[0058] When shooting, the virtual camera VC is placed directly opposite the common shooting surface, and then pointed in the direction of the shooting angle to shoot the space including the common shooting surface with oblique projection (a projection method that is a diagonal projection of orthogonal projection). Alternatively, the virtual camera itself can be tilted in the direction of the shooting angle to shoot the space including the common shooting surface with orthogonal projection. The shot image obtained in this way is called image V corresponding to viewpoint number s = -9.5. -9.5 (i,j). For other viewpoints, the virtual camera position and shooting angle are changed and the space including the common shooting plane is shot in the same manner. Note that the shooting angle corresponding to the viewpoint number s is φ s =θ s +π[rad], where φ s and θ sare the shooting angle and the viewpoint angle corresponding to the viewpoint number s when the clockwise direction is the positive rotation direction with respect to the positive direction of the z axis. In Figs. 11 and 12, the viewpoint angle θ -9.5 and the shooting angle φ -9.5 The following is an example.

[0059] As described above, the horizontal multi-viewpoint image is an image obtained by setting the high-performance lenticular lens surface as the common shooting surface and shooting with a virtual camera. When the horizontal multi-viewpoint image is displayed in a virtual space, light rays traveling in the opposite direction to when the image was shot are reproduced. Therefore, the position of the display surface of the horizontal multi-viewpoint image is the same as the position of the high-performance lenticular lens surface, and the horizontal multi-viewpoint image can be considered to be an image whose appearance changes depending on the viewpoint. In addition, since the original image is generated from the horizontal multi-viewpoint image, the position of the display surface of the original image can also be considered to be the same as the position of the high-performance lenticular lens surface.

[0060] The original image generating unit 41A generates a horizontal multi-viewpoint image V s The image at each viewpoint (i,j) is also copied to the vertical viewpoint to obtain the original image V s,t (i,j), where V s,t (i,j) can be regarded as a function that returns the pixel value of a multi-view image when viewpoint numbers s, t and pixel positions (i,j) are input. In other words, for all viewpoints s and t, V s,t (i,j)=V s Generate an original image so that (i,j) holds. This creates an original image V s,t (i,j) has disparity only in the horizontal direction and no disparity in the vertical direction. H ×N V The original image generator 41A generates the original image V s,t (i,j) is output. If the number of pixels in the element image group display section is different between the first direction D1 and the second direction D2, the original images may be generated separately for portrait display and landscape display. If the number of pixels in the element image group display section is the same between the first direction D1 and the second direction D2, the same original image may be used for portrait display and landscape display.

[0061] (Pattern image generation section) The first pattern image generating unit 43 is a means for generating a first pattern image. The first pattern image generating unit 43 generates a first pattern image displayed on the element image group display unit using one of right-handed circularly polarized pixels and left-handed circularly polarized pixels, and a second pattern image displayed on the other, using difference information between the image displayed by the 3D video display unit and the original image. Here, the first pattern image is displayed using right-handed circularly polarized pixels, and the second pattern image is displayed using left-handed circularly polarized pixels. The second pattern image generating unit 44 is a means for generating a second pattern image. The second pattern image generating unit 44 generates the second pattern image by using difference information between the original image and the image displayed by the 3D video display unit based on the first pattern image.

[0062] The first pattern image and the second pattern image are images that form part of the element image group displayed in the element image group display section, and the element image group is generated in the element image group generation section 42A by additively combining the pixel values ​​of each image. The first pattern image is an image displayed by right-handed circularly polarized pixels of the elemental image group display unit and is used to display a 3D image with horizontal parallax, while the second pattern image is an image displayed by left-handed circularly polarized pixels of the elemental image group display unit and is used to improve the horizontal resolution characteristics of the 3D image.

[0063] The first pattern image is T A (m,n), the second pattern image is T B (m,n), where m and n are the pixel positions in the x and y directions in the pattern image, respectively. A (m,n), T B (m,n) can be regarded as a function that returns the pixel value of the pattern image when a pixel position is input. T A (m,n) returns a pixel value of 0 or more only if the pixel at pixel position (m,n) in the element image group display section is right-handed circularly polarized light, and always returns a pixel value of 0 if the pixel is left-handed circularly polarized light. B(m,n) returns a pixel value of 0 or more only when the pixel at pixel position (m,n) in the element image group display section is left-handed circularly polarized light, and when it is right-handed circularly polarized light, it always returns a pixel value of 0. In other words, the first pattern image can be considered to be an image displayed only with right-handed circularly polarized pixels in the element image group display section, and the second pattern image can be considered to be an image displayed only with left-handed circularly polarized pixels in the element image group display section.

[0064] The first pattern image generating unit 43 and the second pattern image generating unit 44 generate the first to fourth multi-directional images as intermediate data. The number of pixels and pixel pitch of the multi-directional images are the same as those of the element image group display unit, and the depth position of the display surface is the same as the depth position of the high-performance lenticular lens surface. In other words, it is considered that the pixels displaying the multi-directional images are lined up on the high-performance lenticular lens surface. The first multi-directional image is A s,t (i,j), the second multi-directional image is B s,t (i,j), the third multi-directional image is A´ s,t (i,j), the fourth multi-directional image is B´ s,t (i,j), where s and t are viewpoint numbers, and i and j are pixel positions in the x and y directions in the multi-directional image. s,t (i,j), B s,t (i,j), A´ s,t (i,j), B´ s,t (i, j) can be considered as a function that returns a pixel value of a multidirectional image when a viewpoint number and a pixel position of the multidirectional image are input.

[0065] The first multi-directional image and the second multi-directional image are images that are displayed on the three-dimensional video display device when the first pattern image and the second pattern image are displayed on the element image group display section, respectively. The first and second multidirectional images can be generated from the positional relationships illustrated in FIGS. 13A and 13B according to the following equations (3) and (4).

number

number

[0066] Equation (3) generates a first multidirectional image having the high-performance lenticular lens 30 as its display surface based on a first pattern image having the elemental image group display unit 20 as its display surface. For the first pattern image displayed only with pixels of right-handed circularly polarized light, the high-performance lenticular lens 30 functions as a lenticular lens with a period in the x direction. At this time, in the x direction, light from a pixel of the first pattern image is incident on an elemental lens of the corresponding lenticular lens, and is emitted as parallel light from the elemental lens in a direction connecting the pixel position and the center position of the elemental lens. For this reason, when viewed from above as in FIG. 13A, point P2 (x=C) of the first pattern image corresponds to point L1 (x=i) in the first multidirectional image. x On the other hand, since there is no period in the y direction, when viewed from the side as in Figure 13B, point L3 (y = j) in the first multi-directional image corresponds to point P3 (y = j - δt) in the first pattern image. Furthermore, equation (4) generates the second multidirectional image based on the second pattern image. For the second pattern image displayed only with pixels of left-handed circular polarization, the high-performance lenticular lens 30 functions as a lenticular lens with a period in the y direction. For this reason, when viewed from the side as shown in FIG. 13B, point L3 (y=j) in the second multidirectional image corresponds to point P4 (y=C) in the second pattern image. y On the other hand, since there is no period in the x direction, when viewed from above as in Figure 13A, point P1 (x = i - δs) of the second pattern image corresponds to point L1 (x = i) in the second multidirectional image.

[0067] Then, the first pattern image generation unit 43 and the second pattern image generation unit 44 perform optimization calculations in accordance with the following equation (5) based on the least squares method, so as to minimize the error between the original image and the image obtained by additively synthesizing the first multi-directional image and the second multi-directional image.

number

[0068] Based on equation (5), the first pattern image generation unit 43 and the second pattern image generation unit 44 generate the third multi-directional image, the fourth multi-directional image, the first pattern image, and the second pattern image according to the following equations (6), (7), (8), and (9), respectively.

number

number

number

number

[0069] The horizontal viewpoint number in equation (8) is s = D x (m), the vertical viewpoint number in equation (9) is t=D y Calculated from (n). Although not shown in formulas (8) and (9), when generating the first pattern image, the pixel values ​​of the pixels corresponding to the left-handed circularly polarized pixels in the element image group display section must be set to 0. Similarly, when generating the second pattern image, the pixel values ​​of the pixels corresponding to the right-handed circularly polarized pixels in the element image group display section must be set to 0.

[0070] Referring again to FIG. 10, the first pattern image generating unit 43 generates a pattern image V s,t (i, j) and the second pattern image T B Using (m, n) as input, the first pattern image T A (m, n) and outputs it to the second pattern image generating unit 44. The second pattern image generating unit 44 generates the original image V s,t (i, j) and the first pattern image T A Using (m,n) as input, the second pattern image T B (m, n) is generated and output to the first pattern image generating unit 43. The second pattern image that is the first input to the first pattern image generating unit 43 is arbitrary, and for example, all pixel values ​​can be set to 0. Then, the first pattern image generating unit 43 generates the newly generated second pattern image T B (m,n) is used to generate the first pattern image T A (m, n), and the second pattern image generating unit 44 generates the newly generated first pattern image T A (m,n) is used to generate the second pattern image T B(m, n) is generated. In this manner, by repeating the process of repeatedly generating the first pattern image and the second pattern image, the error between the display image of the three-dimensional image display device and the original image can be gradually reduced.

[0071] (Repeat execution part) The repetitive execution unit 45 is a means for repeatedly executing the generation of the first pattern image and the second pattern image alternately. The repetitive execution unit 45 commands the first pattern image generation unit 43 and the second pattern image generation unit 44 to execute the repetitive process. Here, the repetitive execution unit 45 determines whether the repetitive process has been performed a predetermined number of times, and executes the repetitive process until the predetermined number of times. The predetermined number of iterations can be set in advance. The number of iterations required for the error between the image obtained by synthesizing and displaying the first and second multidirectional images and the original image to converge depends on the configuration of the 3D scene data and the configuration of the three-dimensional image display device, but the error generally tends to converge after several dozen iterations. For this reason, the number of iterations can be set to 30 to 70, for example, 50. The repetition execution unit 45 may make a determination based on the amount of change in pixel values ​​between the first pattern image and the second pattern image, rather than the number of repetitions. For example, the repetition may be repeated until the amount of change in pixel values ​​from the previously generated pattern image becomes equal to or less than a preset threshold.

[0072] (Elemental image group generation unit) The element image group generating unit 42A generates an element image group by additively combining the first pattern image and the second pattern image, and sends the element image group to the element image group output unit 46. The element image group generating unit 42A generates a first pattern image T A (m, n) and the second pattern image T B Using (m,n) as input, generate a portrait mode element image group as one image. The number of pixels and pixel pitch of the element image group are the same as those of the element image group display unit. The element image group is T A (m,n) and T B It can be generated by adding and synthesizing the pixel values ​​of (m,n).

[0073] As in the first embodiment, the element image group generation unit 42A can generate two types of element image groups: an element image group in portrait mode that has parallax in a first direction, and an element image group in landscape mode that has parallax in a second direction. The first pattern image generating unit 43, the second pattern image generating unit 44, and the repetition executing unit 45 also perform the repetition process of repeating the generation of the first pattern image and the second pattern image in the landscape mode. In the landscape mode, for example, the second pattern image is used to display a 3D image having a parallax in the horizontal direction, and the first pattern image is used to enhance the horizontal resolution characteristics of the 3D image. When the number of pixels of the element image group display unit is different between the first direction D1 and the second direction D2, the original image may be generated separately for the portrait display and the landscape display. When the number of pixels of the element image group display unit is the same between the first direction D1 and the second direction D2, the original image common to the portrait display and the landscape display may be used. The element image group generating unit 42A generates an element image group in the landscape mode as a single image by additively synthesizing the first pattern image and the second pattern image. Then, the element image group output unit 46 switches between and outputs two types of element image groups based on the orientation of the 3D image display unit 10, as in the first embodiment.

[0074] The 3D image display device of the second embodiment having the above-mentioned configuration displays an element image group using all pixels of the element image group display unit, and generates the element image group based on an optimization calculation that minimizes the error between the pixel values ​​of the 3D image displayed by the 3D image display device and the pixel values ​​of the original image, thereby improving the horizontal resolution characteristics of the 3D image.

[0075] Next, the operation of the 3D image display device of the second embodiment will be described. The operation of the second embodiment is the same as that of the first embodiment except for the generation process of the elemental image group in the control unit 40A, so the description will be omitted. The generation process of the elemental image group in the control unit 40A will be described with reference to the flowchart shown in FIG. First, the original image generating unit 41A generates an original image from 3D scene data (step S10). Next, the second pattern image generating unit 44 sets an arbitrary initial pixel value to the second pattern image (step S20). The initial pixel value may be set to 0, for example. Thereafter, the process is repeated. First, the first pattern image generating unit 43 generates a first pattern image under the condition that the second pattern image is known (step S30). Next, the second pattern image generating unit 44 generates a second pattern image under the condition that the first pattern image is known (step S40). Then, the repeat execution unit 45 determines whether or not steps S30 and S40 have been repeated a predetermined number of times (step S50). If the number of repetitions is less than the predetermined number of times, the process returns to step S30 and generates a first pattern image. If the number of repetitions is equal to or greater than a predetermined number, the first pattern image generation unit 43 and the second pattern image generation unit 44 output the first pattern image and the second pattern image to the element image group generation unit 42A, and the element image group generation unit 42A generates an element image group (step S60).

[0076] Here, the principle of improving the horizontal resolution characteristic by the element image group generated in the second embodiment will be described. The 3D image display device according to the second embodiment generates the element image group so as to minimize the error between the image obtained by synthesizing and displaying the first and second multidirectional images and the original image. In the above description, the pixel pitch of the first and second multidirectional images is equal to the pixel pitch of the element image group display unit, but this is a convenient explanation for simplifying the mathematical expression. In reality, the first multidirectional image is an image displayed by a lenticular lens with a period in the horizontal direction, so it has a low horizontal resolution and a high vertical resolution. Similarly, the second multidirectional image is an image displayed by a lenticular lens with a period in the vertical direction, so it has a high horizontal resolution and a low vertical resolution.

[0077] If the pixel values ​​of the second pattern image and the second multi-directional image are always forcibly set to 0 and only the first pattern image and the first multi-directional image are generated, the resolution characteristics of the three-dimensional image displayed on the three-dimensional image display device will be equivalent to those displayed in the first embodiment. On the other hand, in the second embodiment, the second pattern image is generated and the second multi-directional image is compositely displayed on the first multi-directional image. Here, since the resolution of the second multi-directional image is higher than that of the first multi-directional image in the horizontal direction, a fine luminance change can be generated in the pixels of the first multi-directional image as a result of the composite display of the second multi-directional image on the first multi-directional image. Since the first multi-directional image and the second multi-directional image are generated by optimization calculation based on Equation (5) on the premise that this luminance change occurs, the horizontal resolution characteristics of the three-dimensional image can be improved compared to the case where only the first multi-directional image is displayed.

[0078] Although the above description is given for the case where the orientation of the 3D image display unit is vertical and in portrait mode, the horizontal resolution characteristics of 3D images can be improved in the same manner in the case of landscape mode.

[0079] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, the right-handed circularly polarized pixels of the element image group display unit are basically used for 3D image display in portrait mode, and the left-handed circularly polarized pixels are basically used for 3D image display in landscape mode, but the correspondence may be reversed. That is, the right-handed circularly polarized pixels may be used for landscape mode, and the left-handed circularly polarized pixels may be used for portrait mode. Similarly, in the second embodiment, the right-handed circularly polarized pixels of the element image group display unit are used to display 3D images with horizontal parallax, and the left-handed circularly polarized pixels are used to improve the horizontal resolution characteristics of the 3D images, but the correspondence may be reversed.

[0080] The order of the first polarizing diffractive lens, the second polarizing diffractive lens, and the lens array may be freely changed in the high-performance lenticular lens 30. However, since there is a general tendency for the polarization of light to be disturbed when it passes through a lens array, it is preferable to place the lens array at the last stage, which can minimize the generation of unnecessary light. In the high-performance lenticular lens 30A according to the modified example, the order of the first polarizing diffractive lens and the second polarizing diffractive lens may be reversed.

[0081] Moreover, the generation of the element image group may be performed not only inside the three-dimensional image display device but also on an external server. In this case, the posture information of the three-dimensional image display device detected by the posture detection unit of the three-dimensional image display device is transmitted to the external server, and the element image group is generated on the external server. Then, the external server transmits the element image group to the three-dimensional image display device, and the three-dimensional image display device can display the element image group on the element image group display unit. In particular, in the second embodiment, since the calculation cost of the generation process of the element image group is high, if the element image group is generated only inside the three-dimensional image display device, the processing time may be long. Therefore, there is an advantage in that the processing time can be shortened by generating the element image group on the external server. The 3D image display device does not have to be a portable display device such as a smartphone terminal or a tablet terminal, but may be a stationary display device such as a monitor of a personal computer (PC). In this case, a PC monitor that can physically rotate the orientation of the display screen by 90 degrees is used, and an acceleration sensor or the like is attached to the PC monitor to detect the posture. The elemental image group can be generated by a PC connected to the PC monitor. [Explanation of symbols]

[0082] 1. Three-dimensional image display device (first embodiment) 10 3D image display unit 12 Spacer 15 screens 20 Element image group display section 21 Display Devices 23 Patterned Optical Film 25 pixels 30 High-performance lenticular lens 30A High-performance lenticular lens (variation) 31 1st polarized diffractive lens 31E Element Lens (First Polarized Diffractive Lens) 32 2nd polarized diffractive lens 32E element lens (second polarized diffractive lens) 33 Lens Array 34 3rd polarized diffractive lens 40 Control section 41 Original image generation section 42 Element image group generation unit 50 Storage section 60 Attitude detection unit

Claims

1. A three-dimensional image display device using an elemental image group having parallax in a first direction and an elemental image group having parallax in a second direction perpendicular to the first direction, an original image generating unit that generates an original image to be used for generating the element image group; an element image group generating unit for generating the element image group; an element image group output unit that outputs the generated element image group; a three-dimensional image display unit that displays a three-dimensional image using the elemental image group, the three-dimensional video display unit includes an elemental image group display unit that displays the elemental image group, and a high-performance lenticular lens onto which light emitted from the elemental image group display unit is incident, the elemental image group display unit is composed of pixels that output right-handed circularly polarized light and pixels that output left-handed circularly polarized light, the high-performance lenticular lens functions as a lenticular lens having a period in either the first direction or the second direction depending on a rotation direction of the incident circularly polarized light, the elemental image group output unit switches between an elemental image group having parallax in the first direction and an elemental image group having parallax in the second direction based on an orientation of the three-dimensional video display unit and outputs the elemental image group to the three-dimensional video display unit. A three-dimensional image display device comprising:

2. The high-performance lenticular lens is formed by overlapping a first polarizing diffractive lens having element lenses arranged in the first direction, a second polarizing diffractive lens having element lenses arranged in the second direction, and a lens array having convex lenses arranged in the first direction and the second direction, the first polarizing diffractive lens and the lens array have an equal lens pitch in the first direction, the second polarizing diffractive lens and the lens array have an equal lens pitch in the second direction, The first polarizing diffractive lens and the second polarizing diffractive lens have a focal length whose sign is inverted between right-handed circularly polarized incident light and left-handed circularly polarized incident light, and the rotation direction of the circularly polarized light is opposite between the incident light and the exiting light, The absolute values ​​of the focal lengths of the first polarizing diffractive lens, the second polarizing diffractive lens, and the lens array are the same.

2. The three-dimensional image display device according to claim 1 .

3. The lens array is formed by overlapping a linear polarizing plate, a quarter-wave plate, and a third polarizing diffractive lens that operates as a convex lens for incident light of right-handed circular polarization.

3. The three-dimensional image display device according to claim 2.

4. a posture detection unit that detects a posture of the three-dimensional image display unit and specifies either the first direction or the second direction as a horizontal direction; the element image group output unit outputs an element image group having parallax in the first direction or the second direction specified in a horizontal direction.

2. The three-dimensional image display device according to claim 1 .

5. The element image group generation unit generating an element image group by setting a pixel value of one of right-handed circularly polarized pixels and left-handed circularly polarized pixels of the element image group display unit to 0 so as to display the element image group having parallax in the first direction; generating the element image group so that one of the pixel values ​​of the right-handed circularly polarized pixels and the left-handed circularly polarized pixels of the element image group display unit is set to 0, and the other is used to display the element image group having parallax in the second direction; 5. The three-dimensional image display device according to claim 1, wherein the three-dimensional image display device is a three-dimensional image display device.

6. a first pattern image generating unit that generates a first pattern image to be displayed on one of right-handed circularly polarized pixels and left-handed circularly polarized pixels on the element image group display unit, and a second pattern image to be displayed on the other of the element image group display unit, using difference information between the image displayed by the three-dimensional video display unit and the original image; a second pattern image generating unit that generates the second pattern image by using difference information between an image displayed by the three-dimensional video display unit based on the first pattern image and the original image; a repeat execution unit that repeats the generation of the first pattern image and the second pattern image alternately, adding and synthesizing the first pattern image and the second pattern image, and generating the element image group based on an optimization calculation so that an error between the three-dimensional image and the original image is minimized; 5. The three-dimensional image display device according to claim 1, wherein the three-dimensional image display device is a three-dimensional image display device.

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