Three-dimensional display device, head-up display system, and mobile body

Abstract

To enable a three-dimensional image to be suitably viewed by users.SOLUTION: A three-dimensional display device 2 includes: a display panel 5 having a display surface including sub-pixels; a parallax barrier 6 having a translucent region 62 and a shield region 61; a position acquisition unit 3 for acquiring the positions of the user's eyes; and a controller 7 for synthesizing a mixed image to be displayed on the display surface. The controller 7 successively allocates a first image or a second image having parallax with respect to the first image to n sub-pixels arranged in accordance with the parallax barrier 6. The numerical aperture of the parallax barrier 6 is 0.5+m / 2n, where m denotes an integer of 0 or more and less than n. The controller 7 causes a sub-pixel observed across one end of the translucent region 62 and a sub-pixel observed across the other end of the translucent region 62 to display a low-luminance image. The number of sub-pixels by which the low-luminance image is displayed is the same on the one end side and the other end side of the translucent region 62.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a three-dimensional display device, a head-up display system, and a moving body.

Background Art

[0002] Conventionally, in order to perform three-dimensional display without using glasses, a three-dimensional display device including an optical element that allows a part of the light emitted from a display panel to reach the right eye and another part of the light emitted from the display panel to reach the left eye is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the three-dimensional display device as described above, it is required to appropriately allow a user to view a three-dimensional image.

[0005] The present disclosure provides a three-dimensional display device, a head-up display system, and a moving body that can appropriately allow a user to view a three-dimensional image.

Means for Solving the Problems

[0006] The three-dimensional display device of the present disclosure includes a display panel, a parallax barrier, a position acquisition unit, and a controller. The display panel has a display surface including a plurality of sub-pixels arranged along a first direction and a second direction intersecting the first direction. The parallax barrier defines the light ray direction of the image light emitted from the display surface. The position acquisition unit acquires the position of at least one of the first eye and the second eye of the user. The controller synthesizes a mixed image including a first image and a second image having a parallax with respect to the first image, which is to be displayed on the display surface, based on the position of at least one of the first eye and the second eye acquired by the position acquisition unit. The parallax barrier has a plurality of strip-shaped light-transmitting regions and a plurality of strip-shaped light-blocking regions, and the light-transmitting regions and the light-blocking regions are alternately arranged along the first direction. The controller continuously assigns the first image or the second image to n sub-pixels arranged according to the tilt angle of the parallax barrier with respect to the second direction. When the aperture ratio x of the parallax barrier is such that m is an integer of 0 or more and less than n, x = 0.5 + m / 2n. The controller causes the sub-pixels observed by one of the first eye and the second eye to cross one end of the light-transmitting region and the sub-pixels observed by the one of the first eye and the second eye to cross the other end of the light-transmitting region among the n sub-pixels to display a low-luminance image with the luminance equally reduced. The number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region.

[0007] The head-up display system of the present disclosure includes a display panel, a parallax barrier, a position acquisition unit, an optical member, and a controller. The display panel has a display surface including a plurality of sub-pixels arranged along a first direction and a second direction intersecting the first direction. The parallax barrier defines a light ray direction of image light emitted from the display surface. The position acquisition unit acquires the position of at least one of a first eye and a second eye of a user. The optical member causes the user to visually recognize the image light emitted from the display surface as a virtual image. The controller synthesizes a mixed image including a first image and a second image having a parallax with respect to the first image, which are to be displayed on the display surface, based on the position of at least one of the first eye and the second eye acquired by the position acquisition unit. The parallax barrier has a plurality of strip-shaped light-transmitting regions and a plurality of strip-shaped light-shielding regions, and the light-transmitting regions and the light-shielding regions are arranged alternately along the first direction. The controller continuously assigns the first image or the second image to n sub-pixels arranged according to the tilt angle of the parallax barrier with respect to the second direction. When the aperture ratio x of the parallax barrier is such that m is an integer of 0 or more and less than n, x = 0.5 + m / 2n. The controller causes a low-luminance image with an equally reduced luminance to be displayed on the sub-pixels observed across one end of the light-transmitting region by one of the first eye and the second eye, and on the sub-pixels observed across the other end of the light-transmitting region by the one of the first eye and the second eye, among the n sub-pixels. The number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region.

[0008] The mobile body of the present disclosure includes a head-up display system. The head-up display system includes a display panel, a parallax barrier, a position acquisition unit, an optical member, and a controller. The display panel has a display surface including a plurality of sub-pixels arranged along a first direction and a second direction intersecting the first direction. The parallax barrier defines the light ray direction of the image light emitted from the display surface. The position acquisition unit acquires the position of at least one of the first eye and the second eye of the user. The optical member causes the user to visually recognize the image light emitted from the display surface as a virtual image. The controller synthesizes a mixed image including a first image and a second image having a parallax with respect to the first image, which are to be displayed on the display surface, based on the position of at least one of the first eye and the second eye acquired by the position acquisition unit. The parallax barrier has a plurality of strip-shaped light-transmitting regions and a plurality of strip-shaped light-blocking regions, and the light-transmitting regions and the light-blocking regions are alternately arranged along the first direction. The controller sequentially assigns the first image or the second image to n sub-pixels arranged according to the tilt angle of the parallax barrier with respect to the second direction. When the aperture ratio x of the parallax barrier is such that m is an integer of 0 or more and less than n, x = 0.5 + m / 2n. The controller causes a low-luminance image with an equally reduced luminance to be displayed on the sub-pixels that are observed by one of the first eye and the second eye across one end of the light-transmitting region and the sub-pixels that are observed by the one of the first eye and the second eye across the other end of the light-transmitting region among the n sub-pixels. The number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region.

Advantages of the Invention

[0009] According to an embodiment of the present disclosure, it is possible to appropriately cause a user to visually recognize a three-dimensional image.

Brief Description of the Drawings

[0010]

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Embodiments for Carrying Out the Invention

[0011] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0012] As shown in FIG. 1, a three-dimensional display system 100 according to an embodiment of the present disclosure includes a detection device 1 and a three-dimensional display device 2. The three-dimensional display system 100 causes an image to be displayed on a display panel 5 of the three-dimensional display device 2. By blocking a part of the image light emitted from the display panel 5 by a parallax barrier 6, different image lights reach the left eye and the right eye of the user, respectively. Hereinafter, the parallax barrier is also referred to as a barrier. The user can view the image stereoscopically because there is a parallax between the image viewed with the left eye and the image viewed with the right eye. When the user moves, the three-dimensional display device 2 adjusts the image to be displayed on the display panel 5 according to the distance between the user's eyes detected by the detection device 1 and the barrier 6. Thereby, the three-dimensional display system 100 can appropriately display a three-dimensional image to the user regardless of the change in the position of the user.

[0013] The detection device 1 detects the position of the user's eyes. The detection device 1 may detect the position of at least one of the user's left eye and right eye. Hereinafter, one of the user's eyes is also referred to as the first eye. The other eye of the user is also referred to as the second eye. In the present disclosure, the left eye is the first eye and the right eye is the second eye, but the left eye may be the second eye and the right eye may be the first eye. The position of the user's eyes is represented by, for example, coordinates in a three-dimensional space, but is not limited thereto. The detection device 1 may include, for example, a camera. The detection device 1 may photograph the user's face with the camera. The detection device 1 may detect the position of the user's eyes from the photographed image of the user's face. The detection device 1 may detect the position of the user's eyes as coordinates in a three-dimensional space from the photographed image by one camera. The detection device 1 may detect the position of the user's eyes as coordinates in a three-dimensional space from the photographed images by two or more cameras. The detection device 1 outputs the position of at least one of the user's left eye and right eye to the three-dimensional display device 2.

[0014] The detection device 1 does not include a camera and may be connected to a camera outside the device. The detection device 1 may include an input terminal for inputting an imaging signal from a camera outside the device. The camera outside the device may be directly connected to the input terminal. The camera outside the device may be indirectly connected to the input terminal via a shared network. The detection device 1 may detect the position of the user's eyes from the video signal input to the input terminal.

[0015] The detection device 1 may include, for example, a sensor. The sensor may be an ultrasonic sensor or an optical sensor, etc. The detection device 1 may detect the position of the user's head by the sensor and detect the position of the user's eyes based on the position of the head. The detection device 1 may detect the position of the user's eyes as coordinates in a three-dimensional space by one or more sensors.

[0016] The three-dimensional display system 100 may not include the detection device 1. When the three-dimensional display system 100 does not include the detection device 1, the three-dimensional display device 2 may include an input terminal for inputting a signal from a detection device outside the system. The detection device outside the system may be directly connected to the input terminal. The detection device outside the system may be indirectly connected to the input terminal via a shared network. The three-dimensional display device 2 may acquire the position of the user's eyes from the detection device outside the system.

[0017] The three-dimensional display device 2 includes a position acquisition unit (hereinafter also referred to as the acquisition unit) 3, a display panel 5, a barrier 6, and a controller 7. The three-dimensional display device 2 may include an irradiator 4.

[0018] The acquisition unit 3 acquires the position of at least one of the user's left and right eyes detected by the detection device 1. The acquisition unit 3 may determine the distance between the user's eyes and the barrier 6 from the acquired position of the user's eyes. The distance between the user's eyes and the barrier 6 may be the distance between at least one of the user's left and right eyes and the barrier 6. Hereinafter, the distance between the user's eyes and the barrier 6 is also referred to as the user's viewing distance.

[0019] The irradiator 4 can irradiate the display panel 5 over its entire surface. The irradiator 4 may be configured to include a light source, a light guide plate, a diffusion plate, a diffusion sheet, and the like. The irradiator 4 emits irradiation light by the light source, and equalizes the irradiation light in the surface direction of the display panel 5 by the light guide plate, the diffusion plate, the diffusion sheet, and the like. The irradiator 4 can emit the equalized light to the display panel 5.

[0020] The controller 7 is connected to each component of the three-dimensional display system 100 and can control each component. The controller 7 is configured as, for example, a processor. The controller 7 may include one or more processors. The processor may include a general-purpose processor that reads a specific program and executes a specific function, and a dedicated processor specialized for a specific process. The dedicated processor may include an application-specific integrated circuit (ASIC). The processor may include a programmable logic device (PLD). The PLD may include a field-programmable gate array (FPGA). The controller 7 may be either a system-on-a-chip (SoC) or a system in a package (SiP) in which one or more processors cooperate. The controller 7 may include a storage unit and store various types of information or a program for operating each component of the three-dimensional display system 100 in the storage unit. The storage unit may be configured as, for example, a semiconductor memory. The storage unit may function as a work memory of the controller 7.

[0021] The display panel 5 is, for example, a display panel such as a transmissive liquid crystal display panel, but is not limited thereto. As shown in FIG. 2, the display panel 5 has a plurality of partition regions on the planar active area 51. The active area 51 displays a mixed image. The active area 51 is also referred to as a display surface. The mixed image includes a left-eye image and a right-eye image having a parallax with respect to the left-eye image. Hereinafter, the left-eye image is also referred to as a first image. The right-eye image is also referred to as a second image. The partition region is a region partitioned by a grid-like black matrix 52 in a first direction and a second direction orthogonal to the first direction. The direction orthogonal to the first direction and the second direction is referred to as a third direction. The first direction may be referred to as a horizontal direction or a parallax direction. The second direction may be referred to as a vertical direction. The third direction may be referred to as a depth direction. The first direction, the second direction, and the third direction are not limited to these respectively. In the drawing, the first direction is represented as the x-axis direction, the second direction is represented as the y-axis direction, and the third direction is represented as the z-axis direction.

[0022] Each of the partition regions corresponds to one subpixel. Therefore, the active area 51 includes a plurality of subpixels arranged in a grid along the horizontal direction and the vertical direction.

[0023] Each subpixel may be configured such that one pixel is composed of a set of three subpixels of R (Red), G (Green), and B corresponding to any one of the colors of R, G, and B. One pixel is also referred to as one picture element. The horizontal direction is, for example, the direction in which a plurality of subpixels constituting one pixel are arranged. The vertical direction is, for example, the direction in which subpixels of the same color are arranged. The display panel 5 is not limited to a transmissive liquid crystal panel and may be other display panels such as an organic EL (Electro Luminescence). When the display panel 5 is a self-emitting display panel, the three-dimensional display device 2 does not have to include the irradiator 4.

[0024] The plurality of sub-pixels arranged in the active area 51 may form a sub-pixel group Pg. The sub-pixel group Pg is the minimum unit for the controller 7 to perform control for displaying an image in the active area 51. The controller 7 causes a left-eye image or a right-eye image to be displayed on the plurality of sub-pixels included in one sub-pixel group Pg. In one sub-pixel group Pg, the number of sub-pixels for displaying a left-eye image and the number of sub-pixels for displaying a right-eye image may be the same.

[0025] In the active area 51, the sub-pixel groups Pg may be repeatedly arranged in the horizontal direction. In the vertical direction, the sub-pixel groups Pg may be repeatedly arranged adjacent to each other at positions shifted by one sub-pixel in the horizontal direction. The sub-pixel group Pg may include sub-pixels in a predetermined row and column. Specifically, the sub-pixel group Pg may include 2×n / b×b sub-pixels P(1) to P(2×n×b) continuously arranged in b (b rows) in the vertical direction and 2×n / b (2×n / b columns) in the horizontal direction. n may be the number of sub-pixels constituting a monocular image. In the example shown in FIG. 2, n = 6 and b = 1. In the active area 51, a sub-pixel group Pg including 12 sub-pixels P1 to P12 continuously arranged in 1 in the vertical direction and 12 in the horizontal direction is arranged.

[0026] The sub-pixels P(1) to P(2×n / b×b) included in all the sub-pixel groups Pg may be collectively controlled by the controller 7. For example, when the controller 7 switches the image to be displayed on the sub-pixel P1 from a left-eye image to a right-eye image, the images to be displayed on the sub-pixels P1 included in all the sub-pixel groups Pg may be simultaneously switched from a left-eye image to a right-eye image.

[0027] As shown in FIG. 1, the barrier 6 is formed by a plane along the active area 51 and is arranged at a predetermined distance (gap) g from the active area 51. The barrier 6 may be located on the side opposite to the irradiator 4 with respect to the display panel 5.

[0028] The barrier 6 defines the ray direction of the image light emitted from the display panel 5. As shown in FIG. 3, the barrier 6 has a plurality of light-shielding surfaces 61 that shield the image light. The plurality of light-shielding surfaces 61 define a light-transmitting region 62 between the adjacent light-shielding surfaces 61. The light-transmitting region 62 has a higher light transmittance than the light-shielding surfaces 61. The light-shielding surfaces 61 have a lower light transmittance than the light-transmitting region 62. Hereinafter, the light-transmitting region 62 is also referred to as the first light-transmitting region. The light-shielding surfaces 61 are also referred to as the second light-transmitting region.

[0029] The light-transmitting region 62 is a portion that transmits the light incident on the barrier 6. The light-transmitting region 62 may transmit light at a first transmittance. The first transmittance is, for example, approximately 100%, but is not limited thereto, and may be a value within a range in which the image light emitted from the display panel 5 can be clearly visually recognized. The first transmittance may be, for example, 80% or more, or 50% or more.

[0030] The light-shielding surface 61 is a portion that blocks the light incident on the barrier 6 and hardly transmits it. That is, the light-shielding surface 61 blocks the image displayed in the active area 51 of the display panel 5 from reaching the user's eyes. The light-shielding surface 61 may transmit light at a second transmittance. The second transmittance is, for example, approximately 0%, but is not limited thereto, and may be a value greater than 0% and close to 0%, such as 0.5%, 1%, or 3%. The first transmittance may be several times or more, for example, 10 times or more greater than the second transmittance. Hereinafter, the light-shielding surface 61 is also referred to as a light-shielding region.

[0031] In the barrier 6, the light-transmitting region 62 may be a plurality of strip-shaped regions extending in a predetermined direction in the plane. The light-transmitting region 62 defines the ray direction, which is the direction in which the image light emitted from the sub-pixel propagates. The predetermined direction is a direction that forms a predetermined angle other than 0° or 90° with the vertical direction. The light-transmitting region 62 and the light-shielding region 61 may extend in a predetermined direction along the active area 51 and be repeatedly arranged alternately in a direction orthogonal to the predetermined direction.

[0032] The line 62b indicating the end of the light-transmitting region 62 extends in a direction inclined at a predetermined angle θ with respect to the vertical direction. The line 62b indicating the end of the light-transmitting region 62 is also referred to as the end line. The predetermined angle θ is also referred to as the barrier tilt angle. The barrier tilt angle θ may be an angle of 0° or more and less than 90°. When the barrier tilt angle θ is greater than 0° (θ > 0°), assuming the horizontal length of the sub-pixel on the display surface is Hp, the vertical length of the sub-pixel on the display surface is Vp, and a and b are natural numbers, the barrier tilt angle θ may be defined by the following formula (1). tanθ=(a×Hp) / (b×Vp) …(1) Here, a and b may be natural numbers equal to each other or different from each other. a and b may be natural numbers that are relatively prime to each other.

[0033] The barrier 6 defines the light ray direction of the image light emitted from the display panel 5 by the light-shielding surface 61 and the light-transmitting region 62. As shown in FIG. 1, by the barrier 6 defining the image light emitted from the sub-pixels arranged in the active area 51, the area on the active area 51 visible to the user's eye is determined. Hereinafter, among the areas within the active area 51, the area within the active area 51 that emits the image light propagating to the position of the user's eye is referred to as the visible area 51a. Also, the area within the active area 51 that emits the image light propagating to the position of the user's left eye is referred to as the left visible area 51aL. The left visible area 51aL is also referred to as the first visible area. The area within the active area 51 that emits the image light propagating to the position of the user's right eye is referred to as the right visible area 51aR. The right visible area 51aR is also referred to as the second visible area.

[0034] As shown in FIG. 1, it is assumed that the left eye and the right eye of the user are positioned at a distance of the viewing distance d from the barrier 6. The viewing distance d is referred to as the OVD (Optimum Viewing Distance). The barrier pitch Bp, which is the arrangement interval in the horizontal direction of the light-transmitting region 62, and the gap g between the active area 51 and the barrier 6 are defined such that the following equations (2) and (3) using the horizontal length Hp of the sub-pixel, the number n of sub-pixels constituting the monocular image, the viewing distance d, and the interpupillary distance E hold. E:d=(n×Hp / b):g …(2) d:Bp=(d+g):(2×n×Hp / b) …(3)

[0035] The viewing distance d is the distance between at least one of the left eye and the right eye of the user and the barrier 6 when the aperture ratio of the barrier is 50% and the horizontal length of the visible region 51a is equal to n sub-pixels. The interpupillary distance E is the distance between the left eye and the right eye of the user. The interpupillary distance E may be a value calculated from the positions of the user's eyes or may be a preset value. When preset, the interpupillary distance E may be, for example, a value in the range of 61.1 mm to 64.4 mm calculated by the research of the National Institute of Advanced Industrial Science and Technology.

[0036] The barrier 6 may be composed of a member having a second transmittance. The barrier 6 may be composed of, for example, a film or a plate-like member. In this case, the light-shielding surface 61 is composed of a film or a plate-like member. The light-transmitting region 62 is composed of an opening provided in the film or the plate-like member. The film is composed of, for example, resin, but is not limited thereto. The plate-like member is composed of, for example, resin or metal, but is not limited thereto. The barrier 6 may be composed of a light-shielding base material or may be composed of a base material containing a light-shielding additive.

[0037] The barrier 6 may be composed of a liquid crystal shutter. The liquid crystal shutter can control the light transmittance according to the applied voltage. The liquid crystal shutter is composed of a plurality of pixels, and the light transmittance in each pixel may be controlled. The liquid crystal shutter can form a region with a high light transmittance or a region with a low light transmittance in an arbitrary shape. When the barrier 6 is composed of a liquid crystal shutter, the light-transmitting region 62 may be a region having a first transmittance. When the barrier 6 is composed of a liquid crystal shutter, the light-shielding surface 61 may be a region having a second transmittance.

[0038] By having the configuration described above, the barrier 6 allows the image light emitted from some of the sub-pixels in the active area 51 to pass through the light-transmitting region 62 and propagate to the user's right eye. The barrier 6 allows the image light emitted from some other sub-pixels to pass through the light-transmitting region 62 and propagate to the user's left eye. When the image light propagates to each of the user's left and right eyes, the image visible to the user's eyes will be described in detail with reference to FIGS. 4 and 5.

[0039] As described above, the left visible region 51aL shown in FIG. 4 is the region on the active area 51 that the user's left eye can see when the image light passing through the light-transmitting region 62 of the barrier 6 reaches the user's left eye. The left invisible region 51bL is the region that the user's left eye cannot see because the image light is blocked by the light-shielding surface 61 of the barrier 6. In FIG. 4, the left visible region 51aL includes half of the sub-pixel P1, the entire sub-pixels P2 to P6, and half of the sub-pixel P7.

[0040] As shown in FIG. 5, the right visible region 51aR is the region on the active area 51 that the user's right eye can see when the image light from some other sub-pixels passing through the light-transmitting region 62 of the barrier 6 reaches the user's right eye. The right invisible region 51bR is the region that the user's right eye cannot see because the image light is blocked by the light-shielding surface 61 of the barrier 6. In FIG. 5, the right visible region 51aR includes half of the sub-pixel P7, the entire sub-pixels P8 to P12, and half of the sub-pixel P1.

[0041] When the left-eye image is displayed on sub-pixels P1 to P6 and the right-eye image is displayed on sub-pixels P7 to P12, the left eye and the right eye visually recognize the images respectively. The left-eye image and the right-eye image are parallax images having a parallax with each other. Specifically, the left eye visually recognizes half of the left-eye image displayed on sub-pixel P1, the entire left-eye image displayed on sub-pixels P2 to P6, and half of the right-eye image displayed on sub-pixel P7. The right eye visually recognizes half of the right-eye image displayed on sub-pixel P7, the entire right-eye image displayed on sub-pixels P8 to P12, and half of the left-eye image displayed on sub-pixel P1. In FIGS. 4 and 5, the sub-pixels displaying the left-eye image are marked with the symbol "L", and the sub-pixels displaying the right-eye image are marked with the symbol "R".

[0042] In this state, the area of the left-eye image visually recognized by the user's left eye is maximized, and the area of the right-eye image is minimized. The area of the right-eye image visually recognized by the user's right eye is maximized, and the area of the left-eye image is minimized. The situation where the user's left eye visually recognizes the right-eye image or the user's right eye visually recognizes the left-eye image is also referred to as crosstalk. The user can visually recognize the three-dimensional image in a state where crosstalk is reduced.

[0043] As described above, when the left-eye image and the right-eye image having a parallax with respect to each other are displayed on the sub-pixels included in the left visible region 51aL and the right visible region 51aR, respectively, a user located at the appropriate viewing distance d can visually recognize the image displayed on the display panel 5 as a three-dimensional image. In the above-described configuration, the left-eye image is displayed on the sub-pixels where more than half is visually recognized by the left eye, and the right-eye image is displayed on the sub-pixels where more than half is visually recognized by the right eye. Not limited to this, the sub-pixels for displaying the left-eye image and the right-eye image may be appropriately determined based on the left visible region 51aL and the right visible region 51aR so that crosstalk is reduced according to the design of the active area 51, the barrier 6, and the like. For example, according to the aperture ratio of the barrier 6 or the like, the left-eye image may be displayed on the sub-pixels where a predetermined ratio or more is visually recognized by the left eye, and the right-eye image may be displayed on the sub-pixels where a predetermined ratio or more is visually recognized by the right eye.

[0044] FIG. 6 shows an example of sub-pixels observed by the left eye and the right eye of a user located at the appropriate viewing position. In FIG. 6, the sub-pixel B crossed by the end line 62b of the light-transmitting region 62 is shown shaded. When the user is located at the appropriate viewing position, the active area 51 is separated into a left visible region 51aL observed by the left eye and a right visible region 51aR observed by the right eye with the end line 62b as a boundary. Since the image displayed on the sub-pixel B is observed by both eyes, the sub-pixel B can be a cause of crosstalk. The controller 7 needs to perform crosstalk reduction processing for reducing crosstalk on the sub-pixel B.

[0045] The number of sub-pixels B that need to be subjected to crosstalk reduction processing is at least p. As shown in FIG. 6, p is a natural number that satisfies the following formula (4). 1 ≦ p ≦ a + b - 1 …(4)

[0046] The crosstalk reduction process may be a brightness reduction process that causes the sub-pixel B to display a low-brightness image. The brightness reduction process may be a process of reducing the brightness of the sub-pixel to be processed to 60%, 50%, or 40% of the normal brightness. The brightness reduction process may be a process of causing the sub-pixel to be processed to display a black image. Hereinafter, causing the black image to be displayed may be described as performing black display or the like.

[0047] The light-transmitting region 62 may have a width based on Hp. That is, the light-transmitting region 62 may have a width that is a natural number multiple of Hp in the horizontal direction. Thereby, when the user moves in the horizontal direction, it is possible to suppress the user from recognizing moiré. The low-brightness image displayed on the sub-pixel B may be a black image.

[0048] FIG. 7A shows an example of a sub-pixel observed by the right eye of a user located at the fixation position through the light-transmitting region 62. The fixation position may be, for example, an observation position where the distance between the user and the barrier 6 is the fixation distance d and the right eye observes the central portion of the right visible region 51aR in the parallax direction. In FIG. 7A, for simplicity, the barrier tilt angle θ is set to 0°. The monocular image is composed of 8 sub-pixels. A black image for reducing crosstalk is displayed on the sub-pixel B that crosses the end line 62b of the light-transmitting region 62. FIG. 7B shows the right visible region 51aR observed by a user who has moved in the parallax direction with respect to the barrier 6 from the observation position of FIG. 7A. In FIGS. 7A and 7B, the configuration of the monocular image is the same. When the light-transmitting region 62 has a width that is a natural number multiple of Hp, as shown in FIGS. 7A and 7B, even when the user moves in the parallax direction, the left eye or the right eye of the user always observes a black image for one sub-pixel within one light-transmitting region 62, so the area of the black image observed by the user does not change. Thereby, when the user moves in the parallax direction, it is possible to suppress the user from recognizing moiré.

[0049] When the distance between the barrier 6 and the user's left and right eyes changes, the range of the left visible region 51aL observed by the left eye and the range of the right visible region 51aR observed by the right eye change. FIG. 8A shows an example of the left visible region and the right visible region when the user's viewing distance is the appropriate viewing distance d. In the case shown in FIG. 8A, since there is no binocular visible region 51aLR where the left visible region 51aL and the right visible region 51aR overlap, the user can view the 3D image with reduced crosstalk.

[0050] FIG. 8B shows an example of the left visible region and the right visible region when the user's viewing distance is longer than the appropriate viewing distance d. In the case shown in FIG. 8B, a binocular visible region 51aLR where a part of the left visible region 51aL and a part of the right visible region 51aR overlap may occur. The binocular visible region 51aLR may occur at the central boundary between the left visible region 51aL and the right visible region 51aR observed through one light-transmitting region 62. FIG. 8C shows an example of the left visible region and the right visible region when the user's viewing distance is shorter than the appropriate viewing distance d. In the case shown in FIG. 8C, the binocular visible region 51aLR may occur. The binocular visible region 51aLR may occur at the both-end boundary between the left visible region 51aL observed through one light-transmitting region 62 and the right visible region 51aR observed through a light-transmitting region 62 adjacent to the one light-transmitting region 62. The binocular visible region 51aLR that may occur when the distance between the barrier 6 and the user's left and right eyes is different from the appropriate viewing distance d causes crosstalk. Therefore, the controller 7 needs to perform crosstalk reduction processing on the sub-pixels included in the binocular visible region 51aLR.

[0051] As shown in FIGS. 8B and 8C, when the distance between the barrier 6 and the user's left and right eyes is different from the appropriate viewing distance d, a binocular non-visible region 51bLR that does not overlap with either the left visible region 51aL or the right visible region 51aR may occur. The binocular non-visible region 51bLR can also be said to be a region where a part of the left non-visible region 51bL and a part of the right non-visible region 51bR overlap.

[0052] When there is a binocular visible region 51aLR, there may be sub-pixels that are determined to be left sub-pixels for displaying a left-eye image included in the left visible region 51aL and that are determined to be right sub-pixels for displaying a right-eye image included in the right visible region 51aR. Hereinafter, sub-pixels that are determined to be left sub-pixels and that are determined to be right sub-pixels are also referred to as third sub-pixels. The third sub-pixels are also referred to as a third display region. Although details will be described later, the number of third sub-pixels included in the sub-pixel group Pg can be calculated based on the appropriate viewing distance d, the observer's viewing distance of the user, and the number of sub-pixels that constitute a monocular image. Hereinafter, the number of third sub-pixels may be simply described as t.

[0053] FIG. 8D shows an example of a left visible region and a right visible region when the observer's viewing distance of the user is the appropriate viewing distance d and the aperture ratio of the barrier 6 is greater than 50%. When the aperture ratio of the barrier 6 exceeds 50%, as shown in FIG. 8D, even if the distance between the barrier 6 and the left and right eyes of the user is the appropriate viewing distance d, a binocular visible region 51aLR may occur. For this reason, the controller 7 needs to perform crosstalk reduction processing on the sub-pixels included in the binocular visible region 51aLR. Hereinafter, the aperture ratio of the barrier 6 is also referred to as the barrier aperture ratio.

[0054] Hereinafter, control of each component of the three-dimensional display system 100 by the controller 7 will be described.

[0055] [When tanθ = Hp / Vp] A case where natural numbers a and b that define the barrier tilt angle θ are a = 1 and b = 1 will be described. According to Equation (4), the number of sub-pixels that need to be subjected to crosstalk reduction processing is at least one.

[0056] (When the barrier aperture ratio is 50%) Assume that the barrier aperture ratio x is 50%. The barrier aperture ratio x is defined by the following equation (5) using the number n of sub-pixels that constitute a monocular image and an integer m that is 0 or more and less than n. x = 0.5 + m / (2 × n) …(5) That is, when m = 0, the barrier opening ratio x becomes 50%.

[0057] The sub-pixel group Pg will be described as being composed of 16 sub-pixels P1 to P16 that are arranged continuously in 1 row vertically and 16 columns horizontally. The controller 7 assigns a right-eye image or a left-eye image to each of the sub-pixels P1 to P16 based on the position of the user's eyes.

[0058] FIG. 9A shows an example of sub-pixels observed by the left and right eyes of a user located at the appropriate viewing position. The appropriate viewing position may be, for example, a viewing position where the distance between the user and the barrier 6 is the appropriate viewing distance d, and the right eye observes the center of the right visible region 51aR in the parallax direction. FIG. 9A shows the case of t = 0 where there is no overlap between the left visible region 51aL and the right visible region 51aR. In FIG. 9A, a right-eye image is continuously assigned to the sub-pixels P1 to P8, and a left-eye image is continuously assigned to the sub-pixels P9 to P16. Therefore, the number n of sub-pixels constituting a monocular image is 8. The right visible region 51aR includes a part of sub-pixels P16, P1, the entire sub-pixels P2 to P7, and a part of sub-pixels P8, P9. The left visible region 51aL includes a part of sub-pixels P8, P9, the entire sub-pixels P10 to P15, and a part of sub-pixels P16, P1. FIG. 9A extracts and shows a part of the right visible region 51aR and the left visible region 51aL, shows the regions observed by the left and right eyes through the light-transmitting region 62 in a shaded manner, and shows the sub-pixels P1 to P16 with their numbers "1" to "16". These illustrate the sub-pixels observed by the left and right eyes of the user, and the same applies to the following drawings. Hereinafter, the areas of the sub-pixels P1 to P16 in the active area 51 may be described as S1 to S16.

[0059] When shown in Fig. 9A, the image displayed on sub-pixel P9 is observed by both eyes simultaneously. The controller 7 may perform a brightness reduction process on sub-pixel P9. Thereby, crosstalk can be reduced. Hereinafter, the user observing the image displayed on the sub-pixel may simply be described as the user observing the sub-pixel and the like. Sub-pixel P9 is a sub-pixel observed by the right eye across one end of the light-transmitting region 62. Sub-pixel P9 is a sub-pixel observed by the left eye across one end of the light-transmitting region 62.

[0060] When shown in Fig. 9A, for sub-pixel P9, more than half of the area S9 is observed by the left eye, and less than half of the area S9 is observed by the right eye. Therefore, when a brightness reduction process is performed on sub-pixel P9, the brightness of the image light reaching the left eye decreases compared to the brightness of the image light reaching the right eye. As a result, the brightness of the image light observed by the user becomes non-uniform, and moiré may occur. The controller 7 may perform the same brightness reduction process on sub-pixel P1 that is displaced by (n + m) (i.e., 8) sub-pixels from sub-pixel P9. In other words, when reducing the brightness of sub-pixel P9 to 50%, the brightness of sub-pixel P1 located (n + m) sub-pixels away from sub-pixel P9 may be reduced to 50%. Thereby, it is possible to suppress the difference in the brightness of the image light observed by the left eye and the brightness of the image light observed by the right eye. Therefore, moiré can be reduced. Sub-pixel P1 is a sub-pixel observed by the right eye across the other end of the light-transmitting region 62. Sub-pixel P1 is a sub-pixel observed by the left eye across the other end of the light-transmitting region 62.

[0061] FIG. 9B shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the parallax direction with respect to the barrier 6 from the viewing position. In FIG. 9B, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the viewing position. In the case shown in FIG. 9B, crosstalk and moiré can be reduced by displaying low-luminance images with the luminance equally reduced on the sub-pixels P1 and P9. In the case shown in FIG. 9B, the areas observed by the right eye of the sub-pixels P1 and P9 are equal to each other, and the areas observed by the left eye are equal to each other. The observation position in FIG. 9B is the observation position corresponding to the head tracking boundary. When the controller 7 determines that the user has moved further in the parallax direction from the observation position in FIG. 9B, the controller 7 may change the configuration of the parallax image. The controller 7 may assign the left-eye image to the sub-pixel P1 and the right-eye image to the sub-pixel P9. Thereby, the user can appropriately view the three-dimensional image.

[0062] Also, in FIG. 9B, half of the area of the sub-pixels P1 and P9 causes crosstalk. The controller 7 may determine that the influence of crosstalk is significant with respect to the number of dots n (8 dots) constituting the monocular image. In this case, the luminance reduction process may be set to black display.

[0063] FIG. 9C shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the depth direction from the viewing position with respect to the barrier 6. FIG. 9C shows the case where the left and right eyes of the user move in a direction away from the barrier 6 along the depth direction. As described above, when the distance between the barrier 6 and the left and right eyes of the user is greater than the viewing distance d, a binocular visible region 51aLR in which a part of the left visible region 51aL and a part of the right visible region 51aR overlap may occur at the central boundary between the left visible region 51aL and the right visible region 51aR observed through one light-transmitting region 62. FIG. 9C shows the case where t = 1 and the overlap between the left visible region 51aL and the right visible region 51aR is exactly the area of one sub-pixel. In FIG. 9C, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the viewing position.

[0064] In the case shown in FIG. 9C, for the sub-pixel P8 that displays the right-eye image, more than half of the area S8 is observed by the right eye, and more than half of the area S8 is observed by the left eye. Since the sub-pixel P8 causes crosstalk, the controller 7 causes a black image to be displayed on the sub-pixel P8. Thereby, crosstalk can be reduced. The sub-pixel P8 is a sub-pixel observed by the right eye across one end of the light-transmitting region 62. The sub-pixel P8 is a sub-pixel observed by the left eye across one end of the light-transmitting region 62. The controller 7 causes a black image to be displayed on the sub-pixel P16 that is displaced by (n + m) (that is, 8) sub-pixels from the sub-pixel P8. Thereby, it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye. Therefore, moiré can be reduced.

[0065] FIG. 9D shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the parallax direction with respect to the barrier 6 from the observation position of FIG. 9C. In FIG. 9D, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the proper viewing positions. In the case shown in FIG. 9D, for the sub-pixel P8 that displays the right-eye image, more than half of the area S8 is observed by the right eye, and more than half of the area S8 is observed by the left eye. Since the sub-pixel P8 causes crosstalk, the controller 7 causes a black image to be displayed on the sub-pixel P8. Thereby, crosstalk can be reduced. Further, the controller 7 causes a black image to be displayed on the sub-pixel P16 that is displaced by (n + m) (i.e., 8) sub-pixels from the sub-pixel P8. Thereby, since it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye, moiré can be reduced. The sub-pixel P8 is a sub-pixel that is observed by the left eye across one end of the light-transmitting region 62. The sub-pixel P16 is a sub-pixel that is observed by the left eye across the other end of the light-transmitting region 62.

[0066] In the case shown in FIG. 9D, for the sub-pixel P9 that displays the left-eye image, more than half of the area S9 is observed by the right eye, and more than half of the area S9 is observed by the left eye. Since the sub-pixel P9 causes crosstalk, the controller 7 causes a black image to be displayed on the sub-pixel P9. Thereby, crosstalk can be reduced. Further, the controller 7 causes a black image to be displayed on the sub-pixel P1 that is displaced by (n + m) sub-pixels from the sub-pixel P9. Thereby, it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye, and moiré can be reduced. The sub-pixel P9 is a sub-pixel that is observed by the right eye across one end of the light-transmitting region 62. The sub-pixel P1 is a sub-pixel that is observed by the right eye across the other end of the light-transmitting region 62.

[0067] The transition from the state of FIG. 9C to the state of FIG. 9D is due to the movement in the parallax direction and is continuously observed by the user. Therefore, from the state of FIG. 9C, black display may be performed on sub-pixels P8, P16, P9, and P1. Thereby, with respect to the movement of the user, there is no change in the number of black displays, and flicker of the screen can be suppressed.

[0068] FIG. 9E shows an example of sub-pixels observed by the left eye and the right eye of a user who has moved in the parallax direction with respect to the barrier 6 from the observation position of FIG. 9D. In FIG. 9E, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left eye and the right eye of the user are at the appropriate viewing positions. In the case shown in FIG. 9E, by displaying a low-luminance image with the luminance equally reduced on sub-pixels P1 and P9, and displaying a low-luminance image with the luminance equally reduced on sub-pixels P8 and P16, crosstalk and moire can be reduced. In the case shown in FIG. 9E, the areas observed by the left eye of sub-pixels P8 and P16 and sub-pixel P10 are equal. Also, the areas observed by the right eye of sub-pixels P2 and P10 and sub-pixel P8 are equal. The observation position of FIG. 9E is the observation position corresponding to the head tracking boundary. When the controller 7 determines that the left eye and the right eye of the user have further moved in the parallax direction from the observation position of FIG. 9E, it may display a black image on sub-pixels P2 and P10 without displaying a black image on sub-pixels P8 and P16. Thereby, it becomes possible to change the configuration of the right-eye image and the configuration of the left-eye image without changing the luminance and crosstalk of the screen, and for the further movement of the user in the parallax direction, the user can appropriately view the three-dimensional image.

[0069] FIG. 9F shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the depth direction with respect to the barrier 6 from the observation position in FIG. 9C. FIG. 9F shows the case where the left and right eyes of the user have further moved in a direction away from the barrier 6 along the depth direction. FIG. 9F shows the case of t = 2 where the overlap between the left visible region 51aL and the right visible region 51aR is exactly two sub-pixels. In FIG. 9F, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the appropriate viewing positions.

[0070] In the case shown in FIG. 9F, for the sub-pixel P9 that displays the left-eye image, more than half of the area S9 is observed by the right eye and more than half of the area S9 is observed by the left eye. Since the sub-pixel P9 causes crosstalk, the controller 7 causes a black image to be displayed on the sub-pixel P9. Thereby, crosstalk can be reduced. Further, the controller 7 causes a black image to be displayed on the sub-pixel P1 that is displaced by (n + m) (that is, eight) sub-pixels from the sub-pixel P9. Thereby, it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye, and moiré can be reduced. The sub-pixel P9 is a sub-pixel observed by the right eye across one end of the light-transmitting region 62, and the sub-pixel P1 is a sub-pixel observed by the right eye across the other end of the light-transmitting region 62. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0071] In the case shown in FIG. 9F, for the sub-pixel P7 that displays the right-eye image, more than half of the area S7 is observed by the right eye, and more than half of the area S7 is observed by the left eye. Since the sub-pixel P7 causes crosstalk, the controller 7 causes a black image to be displayed on the sub-pixel P7. Thereby, crosstalk can be reduced. Further, the controller 7 causes a black image to be displayed on the sub-pixel P15 that is displaced by (n + m) sub-pixels from the sub-pixel P7. Thereby, it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye, and moiré can be reduced. The sub-pixel P7 is a sub-pixel observed by the left eye across one end of the light-transmitting region 62, and the sub-pixel P15 is a sub-pixel observed by the left eye across the other end of the light-transmitting region 62. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0072] In the case shown in FIG. 9F, for the sub-pixel P8, the entire area S8 is observed by the left eye, and the entire area S8 is observed by the right eye. Since the sub-pixel P8 causes crosstalk, the controller 7 causes a black image to be displayed on the sub-pixel P8. Thereby, crosstalk can be reduced. Further, the controller 7 may cause a black image to be displayed on the sub-pixel P16 that is displaced by (n + m) sub-pixels from the sub-pixel P8. In the case shown in FIG. 9F, since the area S8 observed by the right eye and the area S8 observed by the left eye are equal for the sub-pixel P8, even if a black image is displayed on the sub-pixel P8, it is less likely to cause moiré. Therefore, the controller 7 does not have to cause a black image to be displayed on the sub-pixel P16.

[0073] Figures 10A, 10B, and 10C are diagrams for explaining the luminance reduction process performed by the controller 7 on sub-pixels P1 to P16. Figure 10A corresponds to the case of t = 0 shown in FIGS. 9A and 9B, Figure 10B corresponds to the case of t = 1 shown in FIGS. 9C, 9D, and 9E, and Figure 10C corresponds to the case of t = 2 shown in FIG. 9F. In FIGS. 10A, 10B, and 10C, the sub-pixels for displaying a black image to reduce crosstalk and moire are shown shaded. Also, in FIGS. 10A, 10B, and 10C, for ease of illustration, the left visible region 51aL and the right visible region 51aR are shown separately.

[0074] As shown in FIG. 10A, in the case of t = 0, the controller 7 causes the sub-pixel P9 observed by the right eye across one end of the light-transmitting region 62 and the sub-pixel P1 observed by the right eye across the other end of the light-transmitting region 62 to display a black image. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62. In other words, the number of sub-pixels displaying the black image is the same on one end side and the other end side of the right visible region 51aR observed by the right eye through one light-transmitting region 62. The sub-pixel P1 is a sub-pixel displaced by (n + m) (i.e., 8) sub-pixels from the sub-pixel P9. By performing the same luminance reduction process on the sub-pixels P1 and P9, crosstalk and moire can be reduced. The sub-pixel P9 is a sub-pixel observed by the left eye across one end of the light-transmitting region 62. The sub-pixel P1 is a sub-pixel observed by the left eye across the other end of the light-transmitting region 62. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the left visible region 51aL observed by the left eye through one light-transmitting region 62. The images to be displayed on the sub-pixels P1 and P9 may be low-luminance images with the luminance reduced equally.

[0075] As shown in FIG. 10B, as the distances between the user's left and right eyes and the fixation position increase, the number of sub-pixels included in the binocular visible region 51aLR at the central boundary between the left visible region 51aL and the right visible region 51aR increases. When t = 1, the controller 7 adds k (1) black displays to the binocular visible region. A black image is displayed on the sub-pixel P9 observed by the right eye across one end of the light-transmitting region 62 and the sub-pixel P1 observed by the right eye across the other end of the light-transmitting region 62. Thereby, crosstalk and moiré can be reduced. The number of sub-pixels displaying the black image is the same on both the one-end side and the other-end side of the light-transmitting region 62.

[0076] Also, the controller 7 adds k (1) black displays to the binocular visible region 51aLR in the left eye. A black image is displayed on the sub-pixel P8 observed by the left eye across one end of the light-transmitting region 62 and the sub-pixel P16 observed by the left eye across the other end of the light-transmitting region 62. Thereby, crosstalk and moiré can be reduced. The number of sub-pixels displaying the black image is the same on both the one-end side and the other-end side of the light-transmitting region 62.

[0077] As shown in FIG. 10C, as the distances between the user's left and right eyes and the fixation position increase, the number of sub-pixels included in the binocular visible region 51aLR at the central boundary between the left visible region 51aL and the right visible region 51aR increases. When t = 2, the controller 7 adds k (2) black displays to the binocular visible region 51aLR. A black image is displayed on the sub-pixel P9 observed by the right eye across one end of the light-transmitting region 62 and the sub-pixel P1 observed by the right eye across the other end of the light-transmitting region 62. Thereby, crosstalk and moiré can be reduced. The number of sub-pixels displaying the black image is the same on both the one-end side and the other-end side of the light-transmitting region 62.

[0078] Also, as shown in FIG. 10C, the controller 7 adds k (2) black displays to the binocular visible region 51aLR in the left eye. A black image is displayed on the sub-pixel P7 observed by the left eye across one end of the light-transmitting region 62 and the sub-pixel P15 observed by the left eye across the other end of the light-transmitting region 62. This can reduce crosstalk and moiré. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0079] As shown in FIG. 10A, when the user's left and right eyes are at the proper viewing positions, the binocular visible region 51aLR exists on one end side and the other end side of the light-transmitting region 62. The controller 7 displays a black image on at least (m + 1) (i.e., at least 1) sub-pixels P1 included in the binocular visible region 51aLR on one end side of the light-transmitting region 62 and at least (m + 1) sub-pixels P9 included in the binocular visible region 51aLR on the other end side of the light-transmitting region 62. This can reduce crosstalk and moiré.

[0080] As shown in FIGS. 10B and 10C, as the distance between the user's left and right eyes and the proper viewing position increases, the number of sub-pixels included in the binocular visible region 51aLR at the central boundary between the left visible region 51aL and the right visible region 51aR increases. The controller 7 may increase the number of sub-pixels displaying the black image for the sub-pixels included in the binocular visible region 51aLR at the central boundary. In other words, when the user's left and right eyes are not at the proper viewing positions, the controller 7 may display a black image on k sub-pixels out of the sub-pixels included in the binocular visible region 51aLR at the central boundary. k may be a natural number greater than (m + 1). This can reduce crosstalk and moiré even when the user's left and right eyes move from the proper viewing positions.

[0081] (When the barrier aperture ratio is 56.25%) A case where the barrier aperture ratio x is 56.25% will be described. In Equation (5), when n = 8 and m = 1, the barrier aperture ratio x becomes 56.25%. The barrier tilt angle θ, the arrangement of sub-pixels P1 to P16, and the assignment of the right-eye image and the left-eye image to the sub-pixels P1 to P16 shall be the same as the arrangement and assignment shown in FIG. 9A. According to Equation (4), the number of sub-pixels that need to be subjected to crosstalk reduction processing is at least one.

[0082] FIG. 11A shows an example of sub-pixels observed by the left eye and the right eye of a user located at the appropriate viewing position. The appropriate viewing position may be, for example, an observation position where the distance between the user and the barrier 6 is the appropriate viewing distance d, and the right eye observes the central part of the right visible region 51aR in the parallax direction. When the barrier aperture ratio x exceeds 50%, even if the distances between the barrier 6 and the left eye and the right eye of the user are the appropriate viewing distance d, binocular visible regions 51aLR may occur.

[0083] In the case shown in FIG. 11A, for the sub-pixel P9 that displays the left-eye image, more than half of the area S9 is observed by the right eye, and more than half of the area S9 is observed by the left eye. Since the sub-pixel P9 causes crosstalk, the controller 7 causes a black image to be displayed on the sub-pixel P9. Thereby, crosstalk can be reduced. Further, the controller 7 causes a black image to be displayed on the sub-pixel P16 that is displaced by (n + m) (i.e., 9) sub-pixels from the sub-pixel P9. Thereby, it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye, and moiré can be reduced. The sub-pixel P9 is a sub-pixel observed by the right eye across one end of the light-transmitting region, and the sub-pixel P16 is a sub-pixel observed by the right eye across the other end of the light-transmitting region. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0084] In the case shown in FIG. 11A, for the sub-pixel P8 that displays the right-eye image, more than half of the area S8 is observed by the right eye, and more than half of the area S8 is observed by the left eye. Since the sub-pixel P8 causes crosstalk, the controller 7 causes a black image to be displayed on the sub-pixel P8. Thereby, crosstalk can be reduced. Further, the controller 7 causes a black image to be displayed on the sub-pixel P1 that is displaced by (n + m) sub-pixels from the sub-pixel P8. Thereby, it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye, and moiré can be reduced. The sub-pixel P8 is a sub-pixel that is observed by the left eye across one end of the light-transmitting region. The sub-pixel P1 is a sub-pixel that is observed by the left eye across the other end of the light-transmitting region. The number of sub-pixels that display a black image is the same on one end side and the other end side of the light-transmitting region 62.

[0085] FIG. 11B shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the parallax direction from the observation position in FIG. 11A. In FIG. 11B, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the appropriate viewing positions. In FIG. 11B, by displaying a black image on the sub-pixels P1, P8, P9, and P16, crosstalk and moiré can be reduced. In the case shown in FIG. 11B, the areas of the sub-pixel P8 and the sub-pixel P2 observed by the left eye are equal to each other. When the controller 7 determines that the left and right eyes of the user have further moved in the parallax direction from the observation position in FIG. 11B, the controller 7 may not display a black image on the sub-pixel P8 and may display a black image on the sub-pixel P2. In the case shown in FIG. 11B, the areas of the sub-pixel P16 and the sub-pixel P10 observed by the right eye are equal to each other. The observation position in FIG. 11B corresponds to the head tracking boundary. When the controller 7 determines that the left and right eyes of the user have further moved in the parallax direction from the observation position in FIG. 11B, the controller 7 may not display a black image on the sub-pixel P16 and may display a black image on the sub-pixel P10.

[0086] FIG. 11C shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the depth direction from the viewing position with respect to the barrier 6. FIG. 11C shows the case where the left and right eyes of the user move in a direction away from the barrier 6 along the depth direction. FIG. 11C shows the case of t = 1 where the increase in the overlap of the left visible region and the right visible region is exactly the area of one sub-pixel. In FIG. 11C, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the viewing position.

[0087] In the case shown in FIG. 11C, for sub-pixel P7, more than half of the area S7 is observed by the right eye, and more than half of the area S7 is observed by the left eye. For sub-pixel P9, more than half of the area S9 is observed by the right eye, and more than half of the area S9 is observed by the left eye. Since sub-pixels P7 and P9 cause crosstalk, the controller 7 causes black images to be displayed on sub-pixels P7 and P9. Thereby, crosstalk can be reduced. Further, the controller 7 causes a black image to be displayed on sub-pixel P16 that is displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P9. Thereby, it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye. Therefore, moiré can be reduced. Sub-pixel P16 is also a sub-pixel that is displaced by (n + m) sub-pixels from sub-pixel P7. The number of sub-pixels on which black images are displayed is the same on one end side and the other end side of the light-transmitting region 62.

[0088] When shown in Fig. 11C, for sub-pixel P8, the entire area S8 is observed by the right eye and the entire area S8 is observed by the left eye. Since sub-pixel P8 is a cause of crosstalk, controller 7 causes a black image to be displayed on sub-pixel P8. Thereby, crosstalk can be reduced. Controller 7 may cause a black image to be displayed on sub-pixels P1 and P15 which are displaced from sub-pixel P8 by (n + m) sub-pixels. When shown in Fig. 11C, since the same area is observed by both eyes for sub-pixel P8, even if a black image is displayed on sub-pixel P8, it is less likely to cause moiré. Therefore, controller 7 does not have to cause a black image to be displayed on sub-pixels P1 and P15. Thereby, the luminance of the three-dimensional image observed by the user can be improved.

[0089] Fig. 11D shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the parallax direction with respect to barrier 6 from the observation position of Fig. 11C. In Fig. 11D, the configuration of the parallax image displayed in active area 51 is the same as the configuration when the left and right eyes of the user are at the proper viewing positions. When shown in Fig. 11D, by displaying a black image on sub-pixels P7, P9, and P16, crosstalk and moiré can be reduced. When shown in Fig. 11D, the areas observed by the left eye for sub-pixels P10 and P16 and sub-pixel P7 are equal. Also, when shown in Fig. 11D, the areas observed by the right eye for sub-pixels P1 and P10 and sub-pixel P7 are equal. The observation position in Fig. 11D is an observation position corresponding to the head tracking boundary. When controller 7 determines that the left and right eyes of the user have moved further in the parallax direction from the observation position of Fig. 11D, controller 7 may not cause a black image to be displayed on sub-pixels P7 and P16 and may cause a black image to be displayed on sub-pixels P1 and P10.

[0090] FIG. 11E shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the depth direction with respect to the barrier 6 from the observation position of FIG. 11C. FIG. 11E shows the case where the left and right eyes of the user have further moved in the direction away from the barrier 6 along the depth direction. FIG. 11E shows the case of t = 2 where the increase in the overlap of the left visible region and the right visible region is exactly the area of two sub-pixels. In FIG. 11E, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the proper viewing positions.

[0091] In the case shown in FIG. 11E, for sub-pixel P9, more than half of the area S9 is observed by the right eye, and more than half of the area S9 is observed by the left eye. Since sub-pixel P9 causes crosstalk, the controller 7 causes a black image to be displayed on sub-pixel P9. Thereby, crosstalk can be reduced. Further, the controller 7 causes a black image to be displayed on sub-pixel P16 which is displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P9. Thereby, moire can be reduced. Sub-pixel P9 is a sub-pixel observed by the right eye across one end of the light-transmitting region 62. Sub-pixel P16 is a sub-pixel observed by the right eye across the other end of the light-transmitting region 62.

[0092] In the case shown in FIG. 11E, for sub-pixel P6, more than half of the area S6 is observed by the right eye, and more than half of the area S6 is observed by the left eye. Since sub-pixel P6 causes crosstalk, the controller 7 causes a black image to be displayed on sub-pixel P6. Thereby, crosstalk can be reduced. Further, the controller 7 causes a black image to be displayed on sub-pixel P15 which is displaced by (n + m) sub-pixels from sub-pixel P6. Thereby, moire can be reduced. Sub-pixel P6 is a sub-pixel observed by the left eye across one end of the light-transmitting region 62. Sub-pixel P15 is a sub-pixel observed by the left eye across the other end of the light-transmitting region 62.

[0093] When shown in Fig. 11E, for sub-pixel P7, the entire area S7 is observed by the right eye and the entire area S7 is observed by the left eye. For sub-pixel P8, the entire area S8 is observed by the right eye and the entire area S8 is observed by the left eye. Since sub-pixels P7 and P8 cause crosstalk, controller 7 causes black images to be displayed on sub-pixels P7 and P8. Thereby, crosstalk can be reduced. Controller 7 may cause black images to be displayed on sub-pixel P14 which is displaced by (n + m) sub-pixels from sub-pixel P7, and on sub-pixel P1 which is displaced by (n + m) sub-pixels from sub-pixel P8. When shown in Fig. 11E, since the same area is observed by both eyes for sub-pixels P7 and P8, even if black images are displayed on sub-pixels P7 and P8, it is less likely to cause moiré. Therefore, controller 7 does not have to cause black images to be displayed on sub-pixels P1 and P14. Thereby, the luminance of the three-dimensional image observed by the user can be improved.

[0094] Figs. 12A, 12B, and 12C are diagrams for explaining the luminance reduction process performed by controller 7 on sub-pixels P1 to P16. Fig. 12A corresponds to the case of t = 0 shown in Figs. 11A and 11B, Fig. 12B corresponds to the case of t = 1 shown in Figs. 11C and 11D, and Fig. 12C corresponds to the case of t = 2 shown in Fig. 11E. In Figs. 12A, 12B, and 12C, the sub-pixels on which black images are displayed to reduce crosstalk and moiré are shown shaded. Also, in Figs. 12A, 12B, and 12C, for ease of illustration, the left visible region 51aL and the right visible region 51aR are shown separately.

[0095] As shown in FIG. 12A, when t = 0, the controller 7 causes the sub-pixel P9 observed by the right eye across one end of the light-transmitting region 62 and the sub-pixel P16 observed by the right eye across the other end of the light-transmitting region 62 to display a black image. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62. In other words, the number of sub-pixels displaying the black image is the same on one end side and the other end side of the right visible region 51aR observed by the right eye through one light-transmitting region 62. The sub-pixel P16 is a sub-pixel displaced by (n + m) (i.e., 9) sub-pixels from the sub-pixel P9. By performing the same luminance reduction process on the sub-pixels P9 and P16, crosstalk and moire can be reduced.

[0096] Also, as shown in FIG. 12A, the controller 7 causes the sub-pixel P8 observed by the left eye across one end of the light-transmitting region 62 and the sub-pixel P1 observed by the left eye across the other end of the light-transmitting region 62 to display a black image. Thereby, crosstalk and moire can be reduced. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62. In other words, the number of sub-pixels displaying the black image is the same on one end side and the other end side of the left visible region 51aL observed by the left eye through one light-transmitting region 62. The sub-pixel P1 is a sub-pixel displaced by (n + m) sub-pixels from the sub-pixel P8. By performing the same luminance reduction process on the sub-pixels P8 and P1, crosstalk and moire can be reduced.

[0097] As shown in FIG. 12B, when t = 1, the controller 7 causes the sub-pixel P9 observed by the right eye across one end of the light-transmitting region 62 and the sub-pixel P16 observed by the right eye across the other end of the light-transmitting region 62 to display a black image. Thereby, crosstalk and moire can be reduced. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0098] Further, as shown in FIG. 12B, the controller 7 causes the sub-pixels P7 observed by the left eye across one end of the light-transmitting region 62 and the sub-pixels P16 observed by the left eye across the other end of the light-transmitting region 62 to display a black image. This can reduce crosstalk and moire. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0099] Further, as shown in FIG. 12B, when the distances between the barrier 6 and the user's left and right eyes are greater than the appropriate viewing distance d, the number of sub-pixels included in the binocular visible region 51aLR at the central boundary between the left visible region 51aL and the right visible region 51aR increases. The controller 7 causes the sub-pixels P8 included in the binocular visible region 51aLR at the central boundary to display a low-luminance black image. This can reduce crosstalk. The controller 7 may cause the sub-pixels P1 and P15, which are displaced by (n + m) sub-pixels from the sub-pixels P8, to display a black image, or may not cause the sub-pixels P1 and P15 to display a black image.

[0100] As shown in FIG. 12C, when t = 2, the controller 7 causes the sub-pixels P9 observed by the right eye across one end of the light-transmitting region 62 and the sub-pixels P16 observed by the right eye across the other end of the light-transmitting region 62 to display a black image. This can reduce crosstalk and moire. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0101] Further, as shown in FIG. 12C, the controller 7 causes the sub-pixels P6 observed by the left eye across one end of the light-transmitting region 62 and the sub-pixels P15 observed by the left eye across the other end of the light-transmitting region 62 to display a black image. This can reduce crosstalk and moire. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0102] Also, as shown in FIG. 12C, as the distances between the barrier 6 and the user's left and right eyes increase, the number of sub-pixels included in the binocular visible region 51aLR at the central boundary between the left visible region 51aL and the right visible region 51aR increases. The controller 7 causes black images to be displayed on the sub-pixels P7 and P8 included in the binocular visible region 51aLR at the central boundary. Thereby, crosstalk can be reduced. The controller 7 may or may not cause black images to be displayed on the sub-pixels P1 and P14 that are displaced by (n + m) sub-pixels from the sub-pixels P7 and P8.

[0103] As shown in FIG. 12A, when the user is at the proper viewing position, binocular visible regions 51aLR exist on one end side and the other end side of the light-transmitting region 62. The controller 7 causes black images to be displayed on at least (m + 1) (i.e., at least 2) sub-pixels P16 and P1 included in the binocular visible region 51aLR on one end side of the light-transmitting region 62, and at least (m + 1) sub-pixels P8 and P9 included in the binocular visible region 51aLR on the other end side of the light-transmitting region 62. Thereby, crosstalk and moiré can be reduced.

[0104] As shown in FIGS. 12B and 12C, as the distances between the user's left and right eyes and the proper viewing position increase, the number of sub-pixels included in the binocular visible region 51aLR at the central boundary between the left visible region 51aL and the right visible region 51aR increases. The controller 7 may increase the number of sub-pixels on which black images are to be displayed among the sub-pixels included in the binocular visible region 51aLR at the central boundary. In other words, when the user's left and right eyes are not at the proper viewing position, the controller 7 may cause black images to be displayed on k sub-pixels among the sub-pixels included in the binocular visible region 51aLR at the central boundary. k may be a natural number greater than (m + 1). Thereby, even when the user's left and right eyes move from the proper viewing position, crosstalk and moiré can be reduced.

[0105] [When tanθ = 0] A case where the barrier tilt angle θ is tanθ = 0 will be described.

[0106] The case where the barrier opening ratio x is 50% will be described. In Equation (5), when m = 0, the barrier opening ratio x becomes 50%. The sub-pixel group Pg will be described as being composed of 16 sub-pixels P1 to P16 arranged continuously in one row (vertically) and 16 columns (horizontally). The arrangement of the sub-pixels P1 to P16 and the assignment of the right-eye image and the left-eye image to the sub-pixels P1 to P16 shall be the same as the arrangement and assignment shown in FIG. 9A. Since the dependency of the right visible region 51aR and the left visible region 51aL observed by the user on t is the same as the case where tanθ = 0, here, with reference to FIGS. 13A, 13B, and 13C, the luminance reduction process performed by the controller 7 on the sub-pixels P1 to P16 will be described. FIG. 13A corresponds to the case where t = 0, FIG. 13B corresponds to the case where t = 1, and FIG. 13C corresponds to the case where t = 2. In FIGS. 13A, 13B, and 13C, the sub-pixels for which a black image is displayed to reduce crosstalk and moiré are shown shaded. Also, in FIGS. 13A, 13B, and 13C, for ease of illustration, the left visible region 51aL and the right visible region 51aR are shown separately.

[0107] As shown in FIG. 13A, when t = 0, the controller 7 causes the sub-pixel P9 observed by the right eye across one end of the light-transmitting region 62 and the sub-pixel P1 observed by the right eye across the other end of the light-transmitting region 62 to display a black image. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62. In other words, the number of sub-pixels displaying the black image is the same on one end side and the other end side of the right visible region 51aR observed by the right eye through one light-transmitting region 62. The sub-pixel P1 is a sub-pixel displaced from the sub-pixel P9 by (n + m) (i.e., 8) sub-pixels. By performing the same luminance reduction process on the sub-pixels P1 and P9, crosstalk and moiré can be reduced. The sub-pixel P9 is a sub-pixel observed by the left eye across one end of the light-transmitting region 62. The sub-pixel P1 is a sub-pixel observed by the left eye across the other end of the light-transmitting region 62. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the left visible region 51aL observed by the left eye through one light-transmitting region 62.

[0108] As shown in FIG. 13B, as the distances between the user's left and right eyes and the proper viewing position increase, the number of sub-pixels included in the binocular visible region 51aLR at the central boundary between the left visible region 51aL and the right visible region 51aR increases. When t = 1, the controller 7 adds k (1) black displays to the binocular visible region. The controller 7 causes the sub-pixel P9 observed by the right eye across one end of the light-transmitting region 62 and the sub-pixel P1 observed by the right eye across the other end of the light-transmitting region 62 to display a black image. Thereby, crosstalk and moiré can be reduced. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0109] Also, the controller 7 adds k (1) black displays to the binocular visible region 51aLR in the left eye. A black image is displayed on the sub-pixel P8 observed by the left eye across one end of the light-transmitting region 62, and the sub-pixel P16 observed by the left eye across the other end of the light-transmitting region 62. Thereby, crosstalk and moiré can be reduced. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0110] As shown in FIG. 13C, as the distances between the user's left and right eyes and the fixation position increase, the number of sub-pixels included in the binocular visible region 51aLR at the central boundary between the left visible region 51aL and the right visible region 51aR increases. When t = 2, the controller 7 adds k (2) black displays to the binocular visible region. A black image is displayed on the sub-pixel P9 observed by the right eye across one end of the light-transmitting region 62, and the sub-pixel P1 observed by the right eye across the other end of the light-transmitting region 62. Thereby, crosstalk and moiré can be reduced. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0111] Also, as shown in FIG. 13C, the controller 7 adds k (2) black displays to the binocular visible region 51aLR in the left eye. A black image is displayed on the sub-pixel P7 observed by the left eye across one end of the light-transmitting region 62, and the sub-pixel P15 observed by the left eye across the other end of the light-transmitting region 62. Thereby, crosstalk and moiré can be reduced. The number of sub-pixels displaying the black image is the same on one end side and the other end side of the light-transmitting region 62.

[0112] As shown in FIG. 13A, when the left and right eyes of the user are at the proper viewing positions, binocular visible regions 51aLR exist on one end side and the other end side of the light-transmitting region 62. The controller 7 causes a black image to be displayed on at least (m + 1) (i.e., at least one) sub-pixels P1 included in the binocular visible region 51aLR on one end side of the light-transmitting region 62, and at least (m + 1) sub-pixels P9 included in the binocular visible region 51aLR on the other end side of the light-transmitting region 62. Thereby, crosstalk and moire can be reduced.

[0113] As shown in FIGS. 13B and 13C, as the distances between the left and right eyes of the user and the proper viewing position increase, the number of sub-pixels included in the binocular visible region 51aLR at the center boundary between the left visible region 51aL and the right visible region 51aR increases. The controller 7 may increase the number of sub-pixels for which a black image is to be displayed among the sub-pixels included in the binocular visible region 51aLR at the center boundary. In other words, when the left and right eyes of the user are not at the proper viewing positions, the controller 7 may cause a black image to be displayed on k sub-pixels among the sub-pixels included in the binocular visible region 51aLR at the center boundary. k may be a natural number greater than (m + 1). Thereby, even when the left and right eyes of the user move from the proper viewing positions, crosstalk and moire can be reduced.

[0114] [When tanθ = Hp / (2×Vp)] A case where natural numbers a and b that define the barrier tilt angle θ are a = 1 and b = 2 will be described. According to Equation (4), the number of sub-pixels that need to be subjected to crosstalk reduction processing is at least two.

[0115] (When the barrier aperture ratio is 50%) A case where the barrier aperture ratio x is 50% will be described. In Equation (5), when n = 8 and m = 1, the barrier aperture ratio x becomes 50%.

[0116] The sub-pixel group Pg will be described as being composed of 16 sub-pixels P1 to P16 arranged continuously in 2 (2 rows) in the vertical direction and 8 (8 columns) in the horizontal direction. The sub-pixels P1 to P16 may be arranged such that the numbers decrease in the row direction and increase in the column direction. The row direction refers to the direction from left to right in FIG. 12A. The column direction refers to the direction from top to bottom in FIG. 12A. The controller 7 assigns a right-eye image or a left-eye image to each of the sub-pixels P1 to P16 based on the position of the user's eyes. Hereinafter, a right-eye image is continuously assigned to the sub-pixels P2 to P9, and a left-eye image is continuously assigned to the sub-pixels P10 to P16 and P1. Therefore, the number n of sub-pixels constituting a monocular image is 8.

[0117] FIG. 14A shows an example of sub-pixels observed by the left and right eyes of a user located at the proper viewing position. The proper viewing position may be, for example, an observation position where the distance between the user and the barrier 6 is the proper viewing distance d and the right eye observes the central part of the right visible region 51aR in the parallax direction. FIG. 14A shows the case of t = 0 where there is no overlap between the left visible region 51aL and the right visible region 51aR. In FIG. 14A, a right-eye image is continuously assigned to the sub-pixels P2 to P9, and a left-eye image is continuously assigned to the sub-pixels P10 to P16 and P1. Therefore, the number n of sub-pixels constituting a monocular image is 8. The right visible region 51aR includes a part of the sub-pixels P1 and P2, the entire sub-pixels P3 to P8, and a part of the sub-pixels P9 and P10. The left visible region 51aL includes a part of the sub-pixels P9 and P10, the entire sub-pixels P11 to P16, and a part of the sub-pixels P1 and P2. According to Equation (4), the number of sub-pixels that need to be subjected to the luminance reduction process is at least 2.

[0118] In the case shown in FIG. 14A, since the sub-pixel P2 is observed by both eyes simultaneously, the controller 7 may perform a luminance reduction process on the sub-pixel P2. Thereby, crosstalk can be reduced. For the sub-pixel P2, more than half of the area S2 is observed by the right eye, and less than half of the area S2 is observed by the left eye. Therefore, when the luminance reduction process is performed on the sub-pixel P2, the luminance of the image light reaching the right eye becomes lower than the luminance of the image light reaching the left eye. As a result, the luminance of the image light observed by the user becomes non-uniform, and moire may occur. The controller 7 may display an image in which the luminance is equally reduced on the sub-pixel P2 and the sub-pixel P10 that is displaced by (n + m) (i.e., 8) sub-pixels from the sub-pixel P2. The controller 7 may, for example, display an image in which the luminance is reduced to 50% on the sub-pixel P2 and the sub-pixel P10. Thereby, it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye. Therefore, moire can be reduced.

[0119] In the case shown in FIG. 14A, when the area S2 observed by the right eye and the area S10 observed by the right eye are summed up, it amounts to one sub-pixel. When the area S2 observed by the left eye and the area S10 observed by the left eye are summed up, it amounts to one sub-pixel. Therefore, as described above, it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye. Therefore, moire can be reduced.

[0120] Regarding sub-pixels P1 and P9 as well, it is the same as sub-pixels P2 and P10. The controller 7 may display an image in which the luminance is equally reduced on the sub-pixel P1 simultaneously observed by both eyes and the sub-pixel P9 displaced by (n + m) sub-pixels from the sub-pixel P1. Thereby, crosstalk and moiré can be reduced. Sub-pixels P1 and P2 are sub-pixels observed by the right eye across one end of the light-transmitting region 62, and sub-pixels P9 and P10 are sub-pixels observed by the right eye across the other end of the light-transmitting region 62. The number of sub-pixels subjected to the luminance reduction process is the same on one end side and the other end side of the light-transmitting region 62 observed by the right eye. Sub-pixels P1 and P2 are sub-pixels observed by the left eye across one end of the light-transmitting region 62, and sub-pixels P9 and P10 are sub-pixels observed by the left eye across the other end of the light-transmitting region 62. Therefore, the number of sub-pixels subjected to the luminance reduction process is the same on one end side and the other end side of the light-transmitting region 62 observed by the left eye.

[0121] As described above, when the barrier aperture ratio is 50% and the left-eye image and the right-eye image are each composed of n sub-pixels, when performing the luminance reduction process on one sub-pixel, moiré can be reduced by performing the same luminance reduction process on the sub-pixel displaced by (n + m) sub-pixels from the one sub-pixel. The luminance reduction process may be a process of displaying a black image.

[0122] Figures 14B and 14C each show an example of sub-pixels observed by the left and right eyes of a user who has moved in the parallax direction with respect to the barrier 6 from the observation position in Figure 14A. The parallax direction is the horizontal direction in Figures 14B and 14C. The moving directions of the user in Figures 14B and 14C are different. In Figures 14B and 14C, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the proper viewing positions. The observation positions in Figures 14B and 14C are the observation positions corresponding to the head-tracking boundary. When the controller 7 determines that the positions of the left and right eyes of the user have further moved along the parallax direction, the controller 7 may change the configuration of the parallax image.

[0123] In the cases shown in Figures 14A, 14B, and 14C, the sub-pixel P1 that displays the left-eye image is observed by both eyes. More than half of the area S1 is observed by the left eye, and the area S1 observed by the right eye is half of the entire area S1. The sub-pixel P10 that displays the left-eye image is observed by both eyes. More than half of the area S10 is observed by the left eye, and the area S10 observed by the right eye is half of the entire area S10. The controller 7 may determine that the influence of the sub-pixels P1 and P10 on the occurrence of crosstalk is small with respect to the number of dots (8 dots) constituting the left-eye image. The controller 7 may display a left-eye image with the brightness reduced to 60%, 50%, or 40% etc. without displaying a black image on the sub-pixels P1 and P10.

[0124] When shown in FIGS. 14A, 14B, and 14C, the sub-pixel P2 that displays the right-eye image is observed by both eyes, but more than half of the area S2 is observed by the right eye, and the area S2 observed by the left eye is half of the entire area S2. The sub-pixel P9 that displays the right-eye image is observed by both eyes, but more than half of the area S9 is observed by the right eye, and the area S9 observed by the left eye is half of the entire area S9. The controller 7 may determine that the influence of the sub-pixels P2 and P9 on the occurrence of crosstalk is small with respect to the number of dots (8) constituting the right-eye image. The controller 7 may display a left-eye image with the brightness reduced to 60%, 50%, or 40% etc. instead of displaying a black image on the sub-pixels P1 and P10.

[0125] When shown in FIG. 14A, when the controller 7 reduces the brightness of the sub-pixels P1, P2, P9, and P10 to 50%, the right eye observes 25% of the area S1 and 25% of the area S10. Therefore, the crosstalk rate of the right eye, that is, the ratio of the brightness of the left-eye image observed by the right eye to the brightness of the right-eye image observed by the right eye, is given by (0.5×0.5) / (6 + 2×0.5), which is approximately 3.6%. It can be said that the crosstalk rate of approximately 3.6% is at a level that does not pose a problem. Also, when shown in FIG. 14B, the crosstalk rate of the right eye is approximately 3.6%, and it can be said that it is at a level that does not pose a problem. The ratio of reducing the brightness is not limited to 50%. An upper limit value of the allowable crosstalk rate may be determined, and based on the determined upper limit value, the ratio of reducing the brightness may be determined.

[0126] Figure 14D shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the depth direction from the viewing position with respect to the barrier 6. Figure 14D shows the case where the left and right eyes of the user have further moved in the direction away from the barrier 6 along the depth direction. As described above, when the distance between the barrier 6 and the left and right eyes of the user is greater than the viewing distance d, the binocular visible region 51aLR where a part of the left visible region 51aL and a part of the right visible region 51aR overlap may occur at the central boundary between the left visible region 51aL and the right visible region 51aR observed through one light-transmitting region 62. Figure 14D shows the case of t = 1 where the increase in the overlap between the left visible region 51aL and the right visible region 51aR is exactly the area of one sub-pixel. Figure 14E shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the parallax direction from the observation position of Figure 14D with respect to the barrier 6. In Figures 14D and 14E, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the viewing position.

[0127] In the cases shown in Figures 14D and 14E, for the sub-pixel P9, more than half of the area S9 is observed by the right eye, and more than half of the area S9 is observed by the left eye. Since the sub-pixel P9 causes crosstalk, the controller 7 causes a black image to be displayed on the sub-pixel P9. In the case shown in Figure 14D, the same area is observed by both eyes for the sub-pixel P9, but in the case shown in Figure 14E, since the area observed by the right eye and the area observed by the left eye are different, moiré due to the black display may occur. The controller 7 also causes a black image to be displayed on the sub-pixel P1 that is displaced by (n + m) (i.e., 8) sub-pixels from the sub-pixel P9. Thereby, moiré caused by the display of the black image can be suppressed.

[0128] When shown in FIGS. 14D and 14E, the sub-pixel P1 is a sub-pixel observed by the right eye across one end of the light-transmitting region 62, that is, a sub-pixel to which a luminance reduction process is applied. When the sub-pixel to be processed is a sub-pixel to which a luminance reduction process is applied and is a sub-pixel for displaying a black image, the controller 7 may display a black image on the sub-pixel to be processed. Thereby, crosstalk and moiré can be reduced.

[0129] When shown in FIGS. 14D and 14E, since the sub-pixel P10 is observed by both eyes simultaneously, the controller 7 may apply a luminance reduction process to the sub-pixel P10. For the sub-pixel P10, less than half of the area S10 is observed by the right eye, and more than half of the area S10 is observed by the left eye. Since the sub-pixel P10 is mainly observed by the left eye, when a low-luminance image is displayed on the sub-pixel P10, the luminance of the image light reaching the left eye decreases. The controller 7 may display a low-luminance image with the luminance equally reduced on the sub-pixel P2 observed across one end of the light-transmitting region 62 and the sub-pixel P10 observed across the other end of the light-transmitting region 62. Thereby, it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye. Therefore, moiré can be reduced.

[0130] When shown in FIGS. 14D and 14E, when the area S10 of the sub-pixel P10 observed by the right eye and the area S2 of the sub-pixel P2 observed by the right eye are summed, it becomes equivalent to the area of one sub-pixel. When the area S10 of the sub-pixel P10 observed by the left eye and the area S2 of the sub-pixel P2 observed by the left eye are summed, it becomes equivalent to the area of one sub-pixel. Therefore, since the luminance reduction process for the sub-pixels P2 and P10 is a luminance reduction process equivalent to one sub-pixel for both eyes, the luminance uniformity is maintained.

[0131] When shown in FIGS. 14D and 14E, since the sub-pixel P8 is observed simultaneously by both eyes, the controller 7 may perform a luminance reduction process on the sub-pixel P8. For the sub-pixel P8, more than half of the area S8 is observed by the right eye, and less than half of the area S8 is observed by the left eye. Since the sub-pixel P8 is mainly observed by the right eye, when a low-luminance image is displayed on the sub-pixel P8, the luminance of the image light reaching the right eye decreases. The controller 7 may display a low-luminance image with the luminance equally reduced on the sub-pixel P8 observed across one end of the light-transmitting region 62 and the sub-pixel P16 observed across the other end of the light-transmitting region 62. Thereby, it is possible to suppress the difference between the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye. Therefore, moiré can be reduced.

[0132] When shown in FIGS. 14D and 14E, when the area S8 of the sub-pixel P8 observed by the right eye and the area S16 of the sub-pixel P16 observed by the right eye are summed up, it becomes equivalent to the area of one sub-pixel. When the area S8 of the sub-pixel P8 observed by the left eye and the area S16 of the sub-pixel P16 observed by the left eye are summed up, it becomes equivalent to the area of one sub-pixel. Therefore, since the luminance reduction process for the sub-pixels P8 and P16 is a luminance reduction process for one sub-pixel for both eyes, the luminance uniformity is maintained.

[0133] FIG. 14F shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the depth direction with respect to the barrier 6 from the observation position of FIG. 14D. FIG. 14F shows the case where the left and right eyes of the user have moved in a direction away from the barrier 6 along the depth direction. FIG. 14F shows the case of t = 2 where the increase in the overlap between the left visible region 51aL and the right visible region 51aR is exactly the area of two sub-pixels. FIG. 14G shows an example of sub-pixels observed by the left and right eyes of a user who has moved along the parallax direction from the observation position shown in FIG. 14F. In FIGS. 14F and 14G, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the appropriate viewing positions.

[0134] When shown in FIGS. 14F and 14G, for sub-pixel P8, more than half of area S8 is observed by the right eye, and more than half of area S8 is observed by the left eye. For sub-pixel P9, more than half of area S9 is observed by the right eye, and more than half of area S9 is observed by the left eye. Since sub-pixels P8 and P9 cause crosstalk, controller 7 causes black images to be displayed on sub-pixels P8 and P9. Thereby, crosstalk can be reduced. Since the areas observed by the right eye and the areas observed by the left eye of the two sub-pixels combining sub-pixel P8 and sub-pixel P9 are different, moiré due to black display may occur. Controller 7 causes black images to be displayed on sub-pixel P16 which is displaced by (n + m) (i.e., 8) sub-pixels from sub-pixel P8, and on sub-pixel P1 which is displaced by (n + m) sub-pixels from sub-pixel P9. Thereby, moiré can be reduced.

[0135] When shown in FIGS. 14F and 14G, since sub-pixel P7 is observed by both eyes simultaneously, controller 7 may perform a luminance reduction process on sub-pixel P7. For sub-pixel P7, more than half of area S7 is observed by the right eye, and less than half of area S7 is observed by the left eye. Since sub-pixel P7 is mainly observed by the right eye, when a low-luminance image is displayed on sub-pixel P7, the luminance of the image light reaching the right eye decreases. Controller 7 may display a low-luminance image with the luminance equally reduced on sub-pixel P7 observed across one end of light-transmitting region 62 and on sub-pixel P15 observed across the other end of light-transmitting region 62. Thereby, it is possible to suppress the difference between the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye. Therefore, moiré can be reduced.

[0136] When shown in FIGS. 14F and 14G, when the area S7 of the sub-pixel P7 observed by the right eye and the area S15 of the sub-pixel P15 observed by the right eye are summed up, it amounts to one sub-pixel. When the area S7 of the sub-pixel P7 observed by the left eye and the area S15 of the sub-pixel P15 observed by the left eye are summed up, it also amounts to one sub-pixel. Therefore, the luminance reduction process for the sub-pixels P7 and P15 is a luminance reduction process for one sub-pixel for both eyes, so the luminance uniformity is maintained.

[0137] When shown in FIGS. 14F and 14G, since the sub-pixel P10 is observed simultaneously by both eyes, the controller 7 may perform a luminance reduction process on the sub-pixel P10. For the sub-pixel P10, less than half of the area S10 is observed by the right eye, and more than half of the area S10 is observed by the left eye. Since the sub-pixel P10 is mainly observed by the left eye, when a low-luminance image is displayed on the sub-pixel P10, the luminance of the image light reaching the left eye decreases. The controller 7 may display a low-luminance image with the luminance equally reduced on the sub-pixel P10 observed across one end of the light-transmitting region 62 and the sub-pixel P2 observed across the other end of the light-transmitting region 62. Thereby, it is possible to suppress the difference in the luminance of the image light observed by the left eye and the luminance of the image light observed by the right eye. Therefore, moiré can be reduced.

[0138] When shown in FIGS. 14F and 14G, when the area S10 of the sub-pixel P10 observed by the right eye and the area S2 of the sub-pixel P2 observed by the right eye are summed up, it amounts to one sub-pixel. When the area S10 of the sub-pixel P10 observed by the left eye and the area S2 of the sub-pixel P2 observed by the left eye are summed up, it also amounts to one sub-pixel. Therefore, the luminance reduction process for the sub-pixels P2 and P10 is a luminance reduction process for one sub-pixel for both eyes, so the luminance uniformity is maintained.

[0139] Figures 15A, 15B, and 15C are diagrams for explaining the luminance reduction process performed by the controller 7 on sub-pixels P1 to P16. Figure 15A corresponds to the case of t = 0 shown in Figures 14A, 14B, and 14C. Figure 15B corresponds to the case of t = 1 shown in Figures 14D and 14E. Figure 15C corresponds to the case of t = 2 shown in Figures 14F and 14G. In Figures 15A, 15B, and 15C, the sub-pixels for displaying a black image are shown hatched in dots. In Figures 15A, 15B, and 15C, the sub-pixels to which the luminance reduction process is applied are shown hatched in oblique lines. Further, in Figures 15A, 15B, and 15C, for ease of illustration, the left visible region 51aL and the right visible region 51aR are shown separately.

[0140] As shown in Figure 15A, in the case of t = 0, the controller 7 causes the sub-pixels P9 and P10, which are observed by the right eye across one end of the light-transmitting region 62, and the sub-pixels P1 and P2, which are observed by the right eye across the other end of the light-transmitting region 62, to display a low-luminance image with the luminance equally reduced. The number of sub-pixels for displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region 62. In other words, the number of sub-pixels for displaying the low-luminance image is the same on one end side and the other end side of the right visible region 51aR observed by the right eye through one light-transmitting region 62. The sub-pixel P1 is a sub-pixel displaced by (n + m) (i.e., 8) sub-pixels from the sub-pixel P9. The sub-pixel P2 is a sub-pixel displaced by (n + m) (i.e., 8) sub-pixels from the sub-pixel P10. By applying the same luminance reduction process to the sub-pixels P1, P2, P9, and P10, crosstalk and moiré can be reduced. The sub-pixels P9 and P10 are sub-pixels observed by the left eye across one end of the light-transmitting region 62. The sub-pixels P1 and P2 are sub-pixels observed by the left eye across the other end of the light-transmitting region 62. It can be said that the number of sub-pixels for displaying the low-luminance image is the same on one end side and the other end side of the left visible region 51aL observed by the left eye through one light-transmitting region 62.

[0141] As shown in FIG. 15B, when t = 1, the controller 7 causes the sub-pixels P9 and P10, which are observed by the right eye across one end of the light-transmitting region 62, and the sub-pixels P1 and P2, which are observed by the right eye across the other end of the light-transmitting region 62, to display a low-luminance image with the luminance equally reduced. Thereby, crosstalk and moire can be reduced. The sub-pixel P1 is a sub-pixel displaced by (n + m) sub-pixels from the sub-pixel P9, and the sub-pixel P2 is a sub-pixel displaced by (n + m) sub-pixels from the sub-pixel P10. The number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region 62.

[0142] As shown in FIG. 15B, the controller 7 causes the sub-pixels P8 and P9, which are observed by the left eye across one end of the light-transmitting region 62, and the sub-pixels P16 and P1, which are observed by the left eye across the other end of the light-transmitting region 62, to display a low-luminance image with the luminance equally reduced. Thereby, crosstalk and moire can be reduced. The sub-pixel P16 is a sub-pixel displaced by (n + m) sub-pixels from the sub-pixel P8, and the sub-pixel P1 is a sub-pixel displaced by (n + m) sub-pixels from the sub-pixel P9. The number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region 62.

[0143] As shown in FIG. 15B, the controller 7 causes the sub-pixel P9, in which more than half of the area is observed by the right eye and more than half of the area is observed by the left eye, to display a black image. Further, the controller 7 also causes the sub-pixel P1, which is displaced by (n + m) sub-pixels from the sub-pixel P9, to display a black image.

[0144] As shown in FIG. 15C, when t = 2, the controller 7 causes the sub-pixels P9 and P10 observed by the right eye to cross one end of the light-transmitting region 62, and the sub-pixels P1 and P2 observed by the right eye to cross the other end of the light-transmitting region 62, to display a low-luminance image with the luminance equally reduced. This can reduce crosstalk and moire. The sub-pixel P1 is a sub-pixel displaced by (n + m) sub-pixels from the sub-pixel P9, and the sub-pixel P2 is a sub-pixel displaced by (n + m) sub-pixels from the sub-pixel P10. The number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region 62.

[0145] As shown in FIG. 15C, the controller 7 causes the sub-pixels P7 and P8 observed by the left eye to cross one end of the light-transmitting region 62, and the sub-pixels P15 and P16 observed by the left eye to cross the other end of the light-transmitting region 62, to display a low-luminance image with the luminance equally reduced. This can reduce crosstalk and moire. The sub-pixel P15 is a sub-pixel displaced by (n + m) sub-pixels from the sub-pixel P7, and the sub-pixel P16 is a sub-pixel displaced by (n + m) sub-pixels from the sub-pixel P8. The number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region 62.

[0146] As shown in FIG. 15C, the controller 7 causes the sub-pixels P8 and P9, where more than half of the area is observed by the right eye and more than half of the area is observed by the left eye, to display a black image. Further, the controller 7 also causes the sub-pixels P16 and P1, which are displaced by (n + m) sub-pixels from the sub-pixels P8 and P9, to display a black image.

[0147] As shown in FIGS. 15B and 15C, as the distances between the left and right eyes of the user and the appropriate viewing position increase, the number of sub-pixels included in the binocular visible region 51aLR at the central boundary between the left visible region 51aL and the right visible region 51aR increases. The controller 7 may increase the number of sub-pixels for which a black image is to be displayed among the sub-pixels included in the binocular visible region 51aLR at the central boundary. In other words, when the left and right eyes of the user are not at the appropriate viewing position, the controller 7 may display a black image on k sub-pixels among the sub-pixels included in the binocular visible region 51aLR at the central boundary. k may be a natural number greater than (m + 1). Thereby, even when the left and right eyes of the user move from the appropriate viewing position, crosstalk and moiré can be reduced.

[0148] (When the barrier aperture ratio is 56.25%) The case where the barrier aperture ratio x is 56.25% will be described. In Equation (5), when n = 8 and m = 1, the barrier aperture ratio x becomes 56.25%. The arrangement of the sub-pixels P1 to P16 is the same as the arrangement when the barrier aperture ratio x is 50%. The assignment of the left-eye image or the right-eye image to the sub-pixels P1 to P16 is the same as the assignment when the barrier aperture ratio x is 50%. According to Equation (4), the number of sub-pixels that need to be subjected to the luminance reduction process is at least 2.

[0149] FIG. 16A shows an example of sub-pixels observed by the left and right eyes of a user located at the appropriate viewing position. In the case shown in FIG. 16A, for sub-pixel P1, more than half of area S1 is observed by the right eye, and more than half of area S1 is observed by the left eye. For sub-pixel P9, more than half of area S9 is observed by the right eye, and more than half of area S9 is observed by the left eye. Sub-pixels P1 and P9 are the causes of crosstalk. Controller 7 causes black images to be displayed on sub-pixels P1 and P9. Thereby, crosstalk can be reduced. Further, controller 7 causes black images to be displayed on sub-pixels P8 and P10 that are displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P1. Also, controller 7 causes black images to be displayed on sub-pixels P2 and P16 that are displaced by (n + m) sub-pixels from sub-pixel P9. Thereby, moiré can be reduced. Sub-pixels P9 and P10 are sub-pixels observed by the right eye across one end of the light-transmitting region 62, and sub-pixels P16 and P1 are sub-pixels observed by the right eye across the other end of the light-transmitting region 62. Sub-pixels P1 and P2 are sub-pixels observed by the left eye across one end of the light-transmitting region 62, and sub-pixels P8 and P9 are sub-pixels observed by the left eye across the other end of the light-transmitting region 62.

[0150] FIG. 16B shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the parallax direction from the observation position of FIG. 16A. In FIG. 16B, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the appropriate viewing positions. In FIG. 16B, by displaying a black image on sub-pixels P16, P1, P2, P8, P9, P10, crosstalk and moiré can be reduced. In the case shown in FIG. 16B, the areas of sub-pixel P3 and sub-pixel P8 observed by the left eye are equal to each other. As for the right eye, the entire area of both is being observed. The observation position in FIG. 16B is the observation position corresponding to the head tracking boundary. When the controller 7 determines that the left and right eyes of the user have further moved in the parallax direction from the observation position of FIG. 16B, it may display a black image on sub-pixel P3 instead of on sub-pixel P8. In the case shown in FIG. 16B, the areas of sub-pixel P16 and sub-pixel P11 observed by the right eye are equal to each other. As for the left eye, the entire area of both is being observed. When the controller 7 determines that the left and right eyes of the user have further moved in the parallax direction from the observation position of FIG. 16B, it may display a black image on sub-pixel P11 instead of on sub-pixel P16. Through the above processing, it becomes possible to move the configuration of the right-eye image and the configuration of the left-eye image by one sub-pixel without changing the luminance.

[0151] FIG. 16C shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the depth direction with respect to the barrier 6 from the observation position of FIG. 16A. FIG. 16C shows the case where the left and right eyes of the user have moved in the direction approaching the barrier 6 along the depth direction. FIG. 16C shows the case of t = 1 where the increase in the overlap of the left visible region 51aL and the right visible region 51aR is exactly the area of one sub-pixel. In FIG. 16C, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the appropriate viewing positions. In the case shown in FIG. 16C, the number of sub-pixels included in the binocular visible region 51aLR where a part of the left visible region 51aL and a part of the right visible region 51aR overlap increases.

[0152] In the case shown in FIG. 16C, for sub-pixel P16, more than half of area S16 is observed by the right eye, and more than half of area S16 is observed by the left eye. For sub-pixel P1, more than half of area S1 is observed by the right eye, and more than half of area S1 is observed by the left eye. Sub-pixels P16 and P1 are the causes of crosstalk. Controller 7 causes black images to be displayed on sub-pixels P16 and P1. Thereby, crosstalk can be reduced. Controller 7 causes black images to be displayed on sub-pixels P9 and P9 that are displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P16 and on sub-pixel P2 that is displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P9. Also, controller 7 causes black images to be displayed on sub-pixels P8 and P8 that are displaced by (n + m) sub-pixels from sub-pixel P1 and on sub-pixel P15 that is displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P8. Thereby, moiré can be reduced. Sub-pixels P8 and P9 are sub-pixels that are observed by the right eye across one end of light-transmitting region 62, and sub-pixels P15 and P16 are sub-pixels that are observed by the right eye across the other end of light-transmitting region 62. The number of sub-pixels on which black images are displayed is the same on one end side and the other end side of light-transmitting region 62. Sub-pixels P1 and P2 are sub-pixels that are observed by the left eye across one end of light-transmitting region 62, and sub-pixels P8 and P9 are sub-pixels that are observed by the left eye across the other end of light-transmitting region 62. The number of sub-pixels on which black images are displayed is the same on one end side and the other end side of light-transmitting region 62.

[0153] FIG. 16D shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the parallax direction from the observation position in FIG. 16C. In FIG. 16D, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the appropriate viewing positions. In FIG. 16D, crosstalk and moiré can be reduced by displaying a black image on sub-pixels P15, P16, P1, P2, P8, and P9. In the case shown in FIG. 16D, the areas of sub-pixel P3 and sub-pixel P8 observed by the left eye are equal to each other. As for the right eye, the entire area of both is being observed. The observation position in FIG. 16D is the observation position corresponding to the head tracking boundary. When the controller 7 determines that the left and right eyes of the user have further moved in the parallax direction from the observation position in FIG. 16D, it may display a black image on sub-pixel P3 instead of on sub-pixel P8. In the case shown in FIG. 16D, the areas of sub-pixel P15 and sub-pixel P10 observed by the right eye are equal to each other. As for the left eye, the entire area of both is being observed. When the controller 7 determines that the left and right eyes of the user have further moved in the parallax direction from the observation position in FIG. 16D, it may display a black image on sub-pixel P10 instead of on sub-pixel P15. Through the above processing, it becomes possible to move the configuration of the right-eye image and the configuration of the left-eye image by one sub-pixel without changing the luminance.

[0154] FIG. 16E shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the depth direction with respect to the barrier 6 from the observation position in FIG. 16C. FIG. 16E shows the case where the left and right eyes of the user have moved in the direction approaching the barrier 6 along the depth direction. FIG. 16E shows the case of t = 2 where the increase in the overlap between the left visible region 51aL and the right visible region 51aR is exactly the area of two sub-pixels. In FIG. 16E, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the appropriate viewing positions. In the case shown in FIG. 16E, the number of sub-pixels included in the binocular visible region 51aLR where a part of the left visible region 51aL and a part of the right visible region 51aR overlap increases.

[0155] In the case shown in FIG. 16E, for sub-pixel P15, more than half of the area S15 is observed by the right eye, and more than half of the area S15 is observed by the left eye. For sub-pixel P16, more than half of the area S16 is observed by the right eye, and more than half of the area S16 is observed by the left eye. For sub-pixel P1, more than half of the area S1 is observed by the right eye, and more than half of the area S1 is observed by the left eye. Sub-pixels P15, P16, and P1 are the causes of crosstalk. Controller 7 causes a black image to be displayed on sub-pixels P15, P16, and P1. Thereby, crosstalk can be reduced. Controller 7 causes a black image to be displayed on sub-pixel P8 which is displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P15. Thereby, moiré can be reduced. Sub-pixel P8 is a sub-pixel that is displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P1.

[0156] In the case shown in FIG. 16E, for sub-pixel P14, less than half of the area S14 is observed by the right eye, and more than half of the area S14 is observed by the left eye. For sub-pixel P2, more than half of the area S2 is observed by the right eye, and less than half of the area S2 is observed by the left eye. Controller 7 causes a low-luminance image with the luminance equally reduced to be displayed on sub-pixel P14 and sub-pixel P7 which is displaced by (n + m) sub-pixels from sub-pixel P14. Controller 7 causes a low-luminance image with the luminance equally reduced to be displayed on sub-pixel P2 and sub-pixel P9 which is displaced by (n + m) sub-pixels from sub-pixel P2. Thereby, crosstalk and moiré can be reduced.

[0157] Figure 16F shows an example of sub-pixels observed by the left and right eyes of a user who has moved in the parallax direction from the observation position in Figure 16E. In Figure 16F, the configuration of the parallax image displayed in the active area 51 is the same as the configuration when the left and right eyes of the user are at the proper viewing positions. In the case shown in Figure 16F, by displaying a black image on sub-pixels P15, P16, P1, and P8, and a low-luminance image with the luminance equally reduced on sub-pixels P14, P2, P7, and P9, crosstalk and moiré can be reduced. In the case shown in Figure 16F, the areas observed by the left eye of sub-pixel P14, sub-pixel P3, and sub-pixel P10 are equal. The observation position in Figure 16F is the observation position corresponding to the head tracking boundary. When the controller 7 determines that the left and right eyes of the user have further moved in the parallax direction from the observation position in Figure 16F, instead of displaying a low-luminance image on sub-pixel P14, a low-luminance image may be displayed on sub-pixel P3 and sub-pixel P10 that is displaced by (n + m) sub-pixels from sub-pixel P3. Also, the areas observed by the left eye of sub-pixel P15, sub-pixel P2, and sub-pixel P9 are equal to each other. Instead of displaying a black image on sub-pixel P15, a black image may be displayed on sub-pixel P2 and sub-pixel P9. In the case shown in Figure 16F, the areas observed by the right eye of sub-pixel P7 and sub-pixel P14 and sub-pixel P3 are equal to each other. When the controller 7 determines that the left and right eyes of the user have further moved in the parallax direction from the observation position in Figure 16F, instead of displaying a low-luminance image on sub-pixels P7 and P14, a low-luminance image may be displayed on sub-pixel P3. Also, the areas observed by the right eye of sub-pixel P8 and sub-pixel P15 and sub-pixel P2 are equal to each other. Instead of displaying a black image on sub-pixels P8 and P15, a black image may be displayed on sub-pixel P2. By performing the above-described processing on the low-luminance image and the black image, it becomes possible to shift the configuration of the right-eye image and the configuration of the left-eye image by one sub-pixel without changing the luminance.

[0158] Figures 17A, 17B, and 17C are diagrams for explaining the luminance reduction process performed by the controller 7 on sub-pixels P1 to P16. Figure 17A corresponds to the case of t = 0 shown in FIGS. 16A and 16B, Figure 17B corresponds to the case of t = 1 shown in FIGS. 16C and 16D, and Figure 17C corresponds to the case of t = 2 shown in FIGS. 16E and 16F. In FIGS. 17A, 17B, and 17C, the sub-pixels for displaying a black image are shown shaded in dots. In FIGS. 17A, 17B, and 17C, the sub-pixels to which the luminance reduction process is applied are shown shaded in oblique lines. Further, in FIGS. 17A, 17B, and 17C, for ease of illustration, the left visible region 51aL and the right visible region 51aR are shown separately.

[0159] As shown in FIG. 17A, in the case of t = 0, the controller 7 performs m (1) black displays at both ends of the barrier opening in the binocular visible region. In the case shown in FIG. 17A, the sub-pixels for which the black display is performed are sub-pixels P1 and P9. Further, sub-pixels P9 and P10 observed across one end of the light-transmitting region 62 by the right eye, and sub-pixels P16 and P1 observed across the other end of the light-transmitting region 62 by the right eye are caused to display a black image with the luminance equally reduced. The number of sub-pixels for displaying the black image is the same on one end side and the other end side of the light-transmitting region 62. In other words, the number of sub-pixels for displaying the black image is the same on one end side and the other end side of the right visible region 51aR observed through one light-transmitting region 62 by the right eye. Sub-pixel P16 is a sub-pixel displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P9. Sub-pixel P1 is a sub-pixel displaced by (n + m) (i.e., 8) sub-pixels from sub-pixel P10. By applying the same black display to sub-pixels P16, P1, P9, and P10, crosstalk and moiré can be reduced.

[0160] The controller 7 causes black images to be displayed on sub-pixels P8 and P9 that are observed by the left eye across one end of the light-transmitting region 62, and sub-pixels P1 and P2 that are observed by the left eye across the other end of the light-transmitting region 62. The number of sub-pixels displaying black images is the same on one end side and the other end side of the light-transmitting region 62. In other words, the number of sub-pixels displaying black images is the same on one end side and the other end side of the left visible region 51aL that is observed by the left eye through one light-transmitting region 62. Sub-pixel P1 is a sub-pixel displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P8. Sub-pixel P2 is a sub-pixel displaced by (n + m) sub-pixels from sub-pixel P9. By applying the same black display to sub-pixels P1, P2, P8, and P9, crosstalk and moire can be reduced.

[0161] As shown in FIG. 17B, the controller 7 causes low-luminance images to be displayed on sub-pixels P8 and P9 that are observed by the right eye across one end of the light-transmitting region 62, and sub-pixels P15 and P16 that are observed by the right eye across the other end of the light-transmitting region 62. Thereby, crosstalk and moire can be reduced. Sub-pixel P15 is a sub-pixel displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P8, and sub-pixel P16 is a sub-pixel displaced by (n + m) sub-pixels from sub-pixel P9. The number of sub-pixels displaying black images is the same on one end side and the other end side of the light-transmitting region 62.

[0162] As shown in FIG. 17B, the controller 7 causes the sub-pixels P1 and P2, which are observed by the left eye across one end of the light-transmitting region 62, and the sub-pixels P8 and P9, which are observed by the right eye across the other end of the light-transmitting region 62, to display a low-luminance image. Thereby, crosstalk and moiré can be reduced. The sub-pixel P8 is a sub-pixel displaced by (n + m) (i.e., 9) sub-pixels from the sub-pixel P1, and the sub-pixel P9 is a sub-pixel displaced by (n + m) sub-pixels from the sub-pixel P2. The number of sub-pixels displaying a black image is the same on one end side and the other end side of the light-transmitting region 62.

[0163] Here, since the sub-pixels P16 and P1 are pixels observed by both eyes and thus black display is performed, the sub-pixel P9, which is displaced by (n + m) sub-pixels from the sub-pixel P16 in the right eye, and further the sub-pixel P2, which is displaced by (n + m) sub-pixels from the sub-pixel P9 in the left eye, become black display, and the sub-pixel P8, which is displaced by (n + m) sub-pixels from P1 in the left eye, and further the sub-pixel P15, which is displaced by (n + m) sub-pixels from the sub-pixel P8 in the right eye, become black display.

[0164] As shown in Fig. 17C, when t = 2, the controller 7 performs k (3) black displays at both ends of the barrier opening in the binocular visible region. In the case shown in Fig. 17C, the sub-pixels where the black display is performed are sub-pixels P15, P16, and P1. Low-luminance images with the luminance equally reduced are displayed on sub-pixels P7, P8 observed across one end of the light-transmitting region 62 by the right eye, and sub-pixels P14, P15 observed across the other end of the light-transmitting region 62 by the right eye. Thereby, crosstalk and moire can be reduced. Sub-pixel P14 is a sub-pixel displaced by (n + m) (i.e., 9) sub-pixels from sub-pixel P7, and sub-pixel P15 is a sub-pixel displaced by (n + m) sub-pixels from sub-pixel P8. The number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region 62.

[0165] As shown in Fig. 17C, the controller 7 displays low-luminance images with the luminance equally reduced on sub-pixels P1, P2 observed across one end of the light-transmitting region 62 by the left eye, and sub-pixels P8, P9 observed across the other end of the light-transmitting region 62 by the left eye. Thereby, crosstalk and moire can be reduced. Sub-pixel P8 is a sub-pixel displaced by (n + m) sub-pixels from sub-pixel P1, and sub-pixel P9 is a sub-pixel displaced by (n + m) sub-pixels from sub-pixel P2. The number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region 62.

[0166] As shown in Fig. 17C, the controller 7 displays black images on sub-pixels P15, P16, and P1 where more than half of the area is observed by the right eye and more than half of the area is observed by the left eye. The controller 7 also displays black images on sub-pixel P8 which is displaced by (n + m) sub-pixels from sub-pixel P15 in the right eye and displaced by (n + m) sub-pixels from sub-pixel P1 in the left eye. Thereby, crosstalk and moire can be reduced.

[0167] As shown in FIG. 17A, when the left and right eyes of the user are at the proper viewing positions, binocular visible regions 51aLR exist on one end side and the other end side of the light-transmitting region 62. The controller 7 causes at least m (i.e., at least one) sub-pixels P1 included in the binocular visible region 51aLR on one end side of the light-transmitting region 62, and at least m sub-pixels P9 included in the binocular visible region 51aLR on the other end side of the light-transmitting region 62 to display a black image. Thereby, crosstalk and moire can be reduced.

[0168] As shown in FIGS. 17B and 17C, as the distances between the left and right eyes of the user and the proper viewing position increase, the number of sub-pixels included in the binocular visible region 51aLR at the central boundary between the left visible region 51aL and the right visible region 51aR increases. The controller 7 may increase the number of sub-pixels for which a black image is to be displayed among the sub-pixels included in the binocular visible region 51aLR at the central boundary. In other words, when the left and right eyes of the user are not at the proper viewing positions, the controller 7 may cause k sub-pixels among the sub-pixels included in the binocular visible region 51aLR at the central boundary to display a black image. k may be a natural number greater than (m + 1). Thereby, even when the left and right eyes of the user move from the proper viewing positions, crosstalk and moire can be reduced.

[0169] When the sub-pixels for which a black image is to be displayed and the sub-pixels for which a low-luminance image is to be displayed are the same sub-pixels, the controller 7 may cause the black image to be displayed on the sub-pixels. In the case shown in FIG. 17C, the sub-pixels P15, P8, and P1 for which a black image is to be displayed are also the sub-pixels for which a low-luminance image is to be displayed. By causing a black image, instead of a low-luminance image, to be displayed on the sub-pixels P15, P8, and P1, crosstalk and moire can be reduced.

[0170] Next, a method for determining the number of third sub-pixels will be described.

[0171] (When the observation distance is the proper viewing distance) Referring to FIG. 1, the control of each component of the three-dimensional display system 100 by the controller 7 when the user is located at the appropriate viewing distance d will be described. The controller 7 determines the left visible region 51aL and the right visible region 51aR within the active area 51 of the display panel 5 based on the position of at least one of the user's left and right eyes. For example, the controller 7 may determine that the user's right eye is at a position horizontally shifted by a predetermined interocular distance E from the position of the left eye based on the position of the user's left eye. The controller may determine the left visible region 51aL and the right visible region 51aR such that the image light passing through each light-transmitting region 62 reaches the user's left and right eyes.

[0172] When the user's viewing distance is the appropriate viewing distance d, both the left visible region 51aL and the right visible region 51aR in one light-transmitting region 62 have a horizontal length of n sub-pixels. Therefore, as shown in FIG. 1, the left visible region 51aL and the right visible region 51aR do not overlap and are arranged alternately horizontally on the display surface of the display panel 5. The controller 7 determines the sub-pixels included in the left visible region 51aL as left sub-pixels. The left sub-pixels are, for example, sub-pixels in which a predetermined ratio or more is included in the left visible region 51aL. The left sub-pixels are also referred to as first sub-pixels or a first display region. Further, the controller 7 determines the sub-pixels included in the right visible region 51aR as right sub-pixels. The right sub-pixels are, for example, sub-pixels in which a predetermined ratio or more is included in the right visible region 51aR. The left sub-pixels are also referred to as second sub-pixels or a second display region. As shown in FIG. 1, the left sub-pixels and the right sub-pixels do not overlap and are arranged alternately horizontally on the display surface of the display panel 5.

[0173] FIG. 18 is a diagram showing sub-pixels visually recognized from the eyes of a user located at the appropriate viewing distance d by image light that has passed through one light-transmitting region 62a. Hereinafter, it will be described assuming that the sub-pixel group Pg includes 12 sub-pixels P1 to P12 arranged continuously in the horizontal direction. FIG. 18 shows a viewing region 70 in which the right eye or left eye of a user located at a distance d from the barrier 6 can visually recognize a predetermined sub-pixel. In one viewing region 70, six sub-pixels that are continuous in the horizontal direction are visually recognized. In FIG. 18, the range that can be visually recognized by the left and right eyes of the user through the light-transmitting region 62a is represented by a broken line. For example, when the left eye of the user is at the position L1 included in the viewing region 70A, the left eye of the user visually recognizes the sub-pixels P1 to P6 through the light-transmitting region 62a. When the left eye of the user moves horizontally from the position of L1 and moves from the viewing region 70A to the viewing region 70B, the sub-pixels visually recognized by the left eye of the user also change. When the left eye of the user is at the position L2 included in the viewing region 70B, the left eye of the user visually recognizes the sub-pixels P2 to P7 through the light-transmitting region 62a. There is a difference of one sub-pixel between the sub-pixels visually recognized from the eyes of the user in adjacent viewing regions 70.

[0174] As described above, in the three-dimensional display system 100, the barrier pitch Bp and the gap g are defined such that among the 2×n sub-pixels arranged horizontally in the sub-pixel group Pg, different n sub-pixels are visible to the left and right eyes of a user at the appropriate viewing distance d. That is, the three-dimensional display system 100 is configured such that a difference of n sub-pixels occurs in the region of sub-pixels visible to the left and right eyes of a user located at the appropriate viewing distance d. Therefore, in FIG. 18, when the left eye is at the position L1 included in the viewing region 70A for viewing the sub-pixels P1 to P6 through the light-transmitting region 62a, the right eye is at the position R1 included in the viewing region 70C for viewing the sub-pixels P7 to P12. At this time, the controller 7 sets the sub-pixels P1 to P6 as the left sub-pixels and displays the left-eye image visible to the left eye of the user. The controller 7 sets the sub-pixels P7 to P12 as the right sub-pixels and displays the right-eye image visible to the right eye of the user. As a result, when the image light that has passed through the light-transmitting region 62a reaches the left and right eyes of the user, the user can view a three-dimensional image with reduced crosstalk. The interpupillary distance E, which is the distance between the left and right eyes of the user, corresponds to the distance between n viewing regions 70. That is, the width of one viewing region 70 is E / n.

[0175] The controller 7 may change the sub-pixels for displaying the right-eye image or the left-eye image according to the position of the user's eyes acquired by the acquisition unit 3. For example, assume that the user moves horizontally at the appropriate viewing distance d and the left eye of the user moves from the position L1 to the position L2. At this time, the controller 7 determines, for example, from the position of the left eye of the user that the left eye is located in the viewing region 70B for viewing the sub-pixels P2 to P7. The controller 7 determines from the position of the left eye of the user that the right eye, which is at a distance of the interpupillary distance E from the left eye, is located in the viewing region 70D for viewing the sub-pixels P8 to P12 and P1. The controller 7 sets the sub-pixels P2 to P7 as the left sub-pixels and the sub-pixels P8 to P12 and P1 as the right sub-pixels. As a result, the user can view a three-dimensional image with reduced crosstalk.

[0176] (When the observation distance is not the comfortable viewing distance) When the user's observation distance is not the comfortable viewing distance d, the control of each component of the three-dimensional display system 100 by the controller 7 will be described. When the user is located at an observation distance d1 different from the comfortable viewing distance d, as shown in FIG. 8B, there may be a binocular visible region 51aLR in which a part of the left visible region 51aL in one light-transmitting region 62a overlaps with a part of the right visible region 51aR. When the binocular visible region 51aLR exists, there may be sub-pixels that are determined to be left sub-pixels for displaying the left-eye image included in the left visible region 51aL and are also determined to be right sub-pixels for displaying the right-eye image included in the right visible region 51aR. Hereinafter, the sub-pixels determined to be left sub-pixels and also determined to be right sub-pixels are also referred to as third sub-pixels. The third sub-pixels are also referred to as the third display region.

[0177] In the case shown in FIG. 8B, when a right-eye image is displayed on the third sub-pixels included in the binocular visible region 51aLR, the right-eye image that the left eye visually recognizes increases. When a left-eye image is displayed on the third sub-pixels included in the binocular visible region 51aLR, the left-eye image that the right eye visually recognizes increases. Therefore, crosstalk may increase regardless of whether a left image or a right-eye image is displayed on the third sub-pixels. The controller 7 performs control to reduce the crosstalk that occurs when the user located at the observation distance d1 views the three-dimensional surface image.

[0178] The controller 7 determines the third sub-pixels that are left sub-pixels and also right sub-pixels based on the user's observation distance.

[0179] (When the observation distance is longer than the comfortable viewing distance) As shown in FIG. 19, assume that the left eye and the right eye of the user are at positions L8-2 and R8-2, respectively, which are at an observation distance Y1 from the barrier 6. The positions L8-2 and R8-2 are positions that have moved in a direction away from the barrier 6 along the depth direction, further away from the positions L8-1 and R8-1, which are at an appropriate viewing distance d from the barrier 6. In this case, the image light emitted from the display panel 5 and passing through the light-transmitting region 62a travels along the optical paths 71A and 71B and reaches the left eye at position L8-2 and the right eye at position R8-2, respectively. The optical path 71A passes through the position L8-1' included in the viewing region 70B at the appropriate viewing distance d. The viewing region 70B corresponds to the region where the sub-pixels P2 to P7 can be viewed in a plane at an appropriate viewing distance d from the barrier 6. The fact that the optical path 71A intersects the viewing region 70B at the position L8-1' when the left eye is at the position L8-2 indicates that the left eye can view the sub-pixels P2 to P7. That is, even when the left eye is at the position L8-2, the controller 7 can identify the sub-pixels that the left eye can view by calculating the viewing region 70 where the optical path 71A intersects. The left eye at the position L8-2 can view the sub-pixels P2 to P7. The optical path 71B passes through the position R8-1 included in the viewing region 70C at the appropriate viewing distance d. The viewing region 70C corresponds to the region where the sub-pixels P7 to P12 can be viewed in a plane at an appropriate viewing distance d from the barrier 6. The right eye at the position R8-2 can view the sub-pixels P7 to P12. The left eye at the position L8-2 and the right eye at the position R8-2 both view the sub-pixel P7. In FIG. 19, the sub-pixel P7 is shown shaded. The sub-pixel P7 is a sub-pixel located at the center-side boundary between the left sub-pixel and the right sub-pixel that can be viewed from one of the light-transmitting regions 62 among the boundaries between the left sub-pixels and the right sub-pixels.

[0180] In FIG. 19, the ratio of the observation distance Y1 from the barrier 6 to the appropriate viewing distance d corresponds to the ratio of the distances at positions L8-2 and R8-2 to the distances at positions L8-1' and R8-1. It can be considered that the images recognized by the left and right eyes of the user separated by the interpupillary distance E at the observation distance Y1 correspond to the images recognized by the left and right eyes of the user, which are shortened by the width of one recognition region 70, i.e., E / n, from the interpupillary distance E at the appropriate viewing distance d. The observation distance Y1 at which the images that can be recognized by both the left and right eyes of the user become 1 sub-pixel is defined by the following equation (6) using the number n of sub-pixels constituting the monocular image, the appropriate viewing distance d, and the interpupillary distance E. d:(E - E / n)=Y1:E …(6) That is, the observation distance Y1 at which the images that can be recognized by both the left and right eyes of the user become 1 sub-pixel is represented by the following equation (7). Y1=(n×d) / (n - 1) …(7)

[0181] As shown in FIG. 20, assume that the left and right eyes of the user are at positions L9-2 and R9-2, respectively, which are separated from the barrier 6 by an observation distance Y2. The positions L9-2 and R9-2 are positions that have moved in a direction away from the barrier 6 along the depth direction, further away from the positions L9-1 and R9-1, which are separated from the barrier 6 by the appropriate viewing distance d. The observation distance Y2 is a distance greater than the above-described observation distance Y1. In FIG. 20, the left eye of the user at position L9-2 visually recognizes the image light emitted from the display panel 5 and traveling along the optical path 71A. The optical path 71A passes through the position L9-1' included in the viewing region 70D at the appropriate viewing distance d. The viewing region 70D corresponds to a region where the sub-pixels P3 to P8 can be visually recognized within a plane separated from the barrier 6 by the appropriate viewing distance d. The left eye at position L9-2 can visually recognize the sub-pixels P3 to P8. The right eye of the user at position R9-2 visually recognizes the image light emitted from the display panel 5 and traveling along the optical path 71B. The optical path 71B passes through the position R9-1 included in the viewing region 70C at the appropriate viewing distance d. The viewing region 70C corresponds to a region where the sub-pixels P7 to P12 can be visually recognized within a plane separated from the barrier 6 by the appropriate viewing distance d. The right eye at position R9-2 can visually recognize the sub-pixels P7 to P12. The left eye at position L9-2 and the right eye at position R9-2 both visually recognize the sub-pixels P7 and P8.

[0182] The images visually recognized by the left eye at position L9-2 and the right eye at position R9-2 at the observation distance Y2 may be considered to correspond to the images visually recognized by the left eye at position L9-1' and the right eye at position R9-1, which are shortened by (E / n)×2 from the interpupillary distance E at the appropriate viewing distance d. The observation distance Y2 at which the image that can be visually recognized by both the left and right eyes of the user becomes 2 sub-pixels is defined by the following equation (8). Y2=(n×d) / (n - 2) …(8)

[0183] As described above, when the observation distance Y is longer than the appropriate viewing distance d, the controller 7 determines the number of the third sub-pixels as X calculated by the following equation (9) using the observation distance Y of the user, the number n of sub-pixels constituting the monocular image, and the appropriate viewing distance d. Y = (n × d) / (n - X) …(9)

[0184] When the observation distance Y is longer than the appropriate viewing distance d, the controller 7 may determine that the third sub-pixel is generated at the boundary on the center side of the left and right sub-pixels visually recognized from one of the light-transmitting regions 62 among the boundaries between the left and right sub-pixels.

[0185] (When the observation distance is shorter than the appropriate viewing distance) As shown in FIG. 21, assume that the left eye and the right eye of the user are at positions L10-2 and R10-2, respectively, which are at an observation distance Y3 from the barrier 6. The positions L10-2 and R10-2 are positions closer to the barrier 6 along the depth direction than the positions L10-1 and R10-1, which are at an appropriate viewing distance d from the barrier 6. In this case, the image light emitted from the display panel 5 travels along the optical paths 71A and 71B, passes through one light-transmitting region 62a, and reaches the left eye at position L10-2 and the right eye at position R10-2, respectively. The optical path 71A passes through the position L10-1' included in the viewing region 70E at the appropriate viewing distance d. The viewing region 70E corresponds to the region where the sub-pixels P12 and P1 to P5 can be viewed in a plane at an appropriate viewing distance d from the barrier 6. The fact that the optical path 71A intersects the viewing region 70E at the position L10-1' when the left eye is at the position L10-2 indicates that the left eye can view the sub-pixels P12 and P1 to P5. That is, even when the left eye is at the position L10-2, the controller 7 can identify the sub-pixels that the left eye can view by calculating the viewing region 70 where the optical path 71A intersects. The left eye at the position L10-2 can view the sub-pixels P12 and P1 to P5. The optical path 71E passes through the position R10-1 included in the viewing region 70C at the appropriate viewing distance d. The viewing region 70C corresponds to the region where the sub-pixels P7 to P12 can be viewed in a plane at an appropriate viewing distance d from the barrier 6. The right eye at the position R10-2 can view the sub-pixels P7 to P12. The left eye at the position L10-2 and the right eye at the position R10-2 both view the sub-pixel P12. In FIG. 21, the sub-pixel P7 is shown shaded. The sub-pixel P12 is a sub-pixel located at the outer boundary between the left sub-pixel and the right sub-pixel that can be viewed from one light-transmitting region 62 among the boundaries between the left sub-pixel and the right sub-pixel.

[0186] In FIG. 21, the ratio of the observation distance Y3 from the barrier 6 to the comfortable viewing distance d corresponds to the ratio of the distances at positions L10-2 and R10-2 to the distances at positions L10-1' and R10-1. The images viewed by the left and right eyes of a user separated by the interpupillary distance E at the observation distance Y3 may be considered to correspond to the images viewed by the left and right eyes of the user, which are lengthened by the width of one viewing region 70, i.e., E / n, from the interpupillary distance E at the comfortable viewing distance d. The observation distance Y3 at which the images that can be viewed by both the left and right eyes of the user become 1 sub-pixel is defined by the following formula (10) using the number n of sub-pixels constituting the monocular image, the comfortable viewing distance d, and the interpupillary distance E. d:(E + E / n)=Y3:E …(10) That is, the observation distance Y3 at which the images that can be viewed by both the left and right eyes of the user become 1 sub-pixel is expressed by the following formula (11). Y3=(n×d) / (n + 1) …(11)

[0187] As shown in FIG. 22, assume that the user's left and right eyes are at positions L11-2 and R11-2, respectively, which are at an observation distance Y4 from the barrier 6. The positions L11-2 and R11-2 are closer to the barrier 6 along the depth direction than the positions L11-1 and R11-1, which are at an appropriate viewing distance d from the barrier 6. The observation distance Y4 is shorter than the above-described observation distance Y3. In FIG. 22, the left eye of the user at position L11-2 visually recognizes the image light emitted from the display panel 5 and traveling along the optical path 71A. The optical path 71A passes through the position L11-1' included in the viewing region 70F at the appropriate viewing distance d. The viewing region 70F corresponds to the region where the sub-pixels P11 to P12 and P1 to P4 can be visually recognized within a plane at an appropriate viewing distance d from the barrier 6. The left eye at position L11-2 can visually recognize the sub-pixels P11 to P12 and P1 to P4. The right eye of the user at position R11-2 visually recognizes the image light emitted from the display panel 5 and traveling along the optical path 71B. The optical path 71B passes through the position R11-1 included in the viewing region 70C at the appropriate viewing distance d. The viewing region 70C corresponds to the region where the sub-pixels P7 to P12 can be visually recognized within a plane at an appropriate viewing distance d from the barrier 6. The right eye at position R11-2 can visually recognize the sub-pixels P7 to P12. The left eye at position L11-2 and the right eye at position R11-2 both visually recognize the sub-pixels P11 and P12.

[0188] At the observation distance Y4, the left eye at position L11-2 and the right eye at position R11-2 may be considered to correspond to the distance between the left eye at position L11-1' and the right eye at position R11-1, which is (E / n)×2 longer than the interocular distance E at the appropriate viewing distance d. The observation distance Y4 at which the image that can be visually recognized by both the user's left and right eyes becomes 2 sub-pixels is defined by the following equation (12). Y4=(n×d) / (n + 2) …(12)

[0189] As described above, when the observation distance Y is shorter than the comfortable viewing distance d, the controller 7 determines the number of third sub-pixels as the number X calculated by the following equation (13) using the user's observation distance Y, the number n of sub-pixels constituting the monocular image, and the comfortable viewing distance d. Y = (n × d) / (n + X) …(13)

[0190] When the observation distance Y is shorter than the comfortable viewing distance d, the controller 7 may determine that the third sub-pixel is generated at the outer boundary between the left sub-pixel and the right sub-pixel that is visually recognized from one light-transmitting region 62 among the boundaries between the left sub-pixel and the right sub-pixel.

[0191] The controller 7 may correct the number of third sub-pixels to be an even number so that the number of left sub-pixels visually recognized by the user's left eye is equal to the number of right sub-pixels visually recognized by the user's right eye. FIG. 23 shows a list of the observation distance Y and the number of third sub-pixels after correction. The controller 7 may, for example, as shown by Correction 1 in FIG. 23, use the smallest even number greater than or equal to the number obtained by rounding up the X calculated by equation (9) or equation (13) to an integer as the number of third sub-pixels. The controller 7 may, for example, as shown by Correction 2 in FIG. 23, use the largest even number not exceeding the X calculated by equation (9) or equation (13) or 0 as the number of third sub-pixels. The controller 7 may, for example, as shown by Correction 3 in FIG. 23, use the smallest even number greater than or equal to the number obtained by rounding down the X calculated by equation (9) or equation (13) to an integer or 0 as the number of third sub-pixels.

[0192] Although the above-described embodiments have been described as representative examples, it is obvious to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes are possible without departing from the scope of the claims. For example, it is possible to combine a plurality of constituent blocks described in the embodiments and examples into one, or to divide one constituent block.

[0193] In the above-described embodiment, in the three-dimensional display system 100, the three-dimensional display device 2 and the detection device 1 have been described as being separate, but the present invention is not limited to this. For example, the three-dimensional display device 2 may have the functions provided by the detection device 1. In such a case, the three-dimensional display device 2 detects the position of at least one of the left eye and the right eye of the user.

[0194] As shown in FIG. 24, the three-dimensional display system 100 can be mounted on a head-up display system 400. The head-up display system 400 is also referred to as a HUD (Head Up Display) 400. The HUD 400 includes the three-dimensional display system 100, an optical member 410, and a projection member 420 having a projection surface 430. The HUD 400 causes the image light emitted from the three-dimensional display system 100 to reach the projection member 420 via the optical member 410. The HUD 400 causes the image light reflected by the projection member 420 to reach the left eye and the right eye of the user. That is, the HUD 400 causes the image light to travel from the three-dimensional display system 100 to the left eye and the right eye of the user along the optical path 440 indicated by the dashed line. The user can visually recognize the image light that has reached along the optical path 440 as a virtual image 450.

[0195] As shown in FIG. 25, the HUD 400 including the three-dimensional display system 100 may be mounted on the moving body 10. A part of the configuration of the HUD 400 may be shared with other devices and components provided in the moving body 10. For example, the moving body 10 may also serve as the projection member 420 for the windshield. When a part of the configuration is shared with other devices and components provided in the moving body 10, the other configuration may be referred to as a HUD module or a three-dimensional display component. The HUD 400 and the three-dimensional display system 100 may be mounted on the moving body 10. The "moving body" in the present disclosure includes vehicles, ships, and aircraft. The "vehicle" in the present disclosure includes automobiles and industrial vehicles, but is not limited thereto, and may include railway vehicles, living vehicles, and fixed-wing aircraft traveling on a runway. Automobiles include, but are not limited to, passenger cars, trucks, buses, motorcycles, and trolley buses, and may include other vehicles traveling on the road. Industrial vehicles include industrial vehicles for agriculture and construction. Industrial vehicles include, but are not limited to, forklifts and golf carts. Industrial vehicles for agriculture include, but are not limited to, tractors, tillers, transplanters, binders, combines, and lawn mowers. Industrial vehicles for construction include, but are not limited to, bulldozers, scrapers, shovel cars, crane cars, dump trucks, and road rollers. Vehicles include those that run manually. Note that the classification of vehicles is not limited to the above. For example, automobiles may include industrial vehicles capable of traveling on the road, and the same vehicle may be included in multiple classifications. The "ship" in the present disclosure includes marine jets, boats, and tankers. The "aircraft" in the present disclosure includes fixed-wing aircraft and rotary-wing aircraft.

[0196] The present disclosure can be implemented in the following aspects of configurations (1) to (10). (1) A display panel having a display surface including a plurality of sub-pixels arranged along a first direction and a second direction intersecting the first direction, a parallax barrier that defines a light ray direction of image light emitted from the display surface, a position acquisition unit that acquires the position of at least one of the first eye and the second eye of the user, A controller that synthesizes a mixed image including a first image and a second image having a parallax with respect to the first image, and that is to be displayed on the display surface based on the position of at least one of the first eye and the second eye acquired by the position acquisition unit. The parallax barrier has a plurality of strip-shaped light-transmitting regions and a plurality of strip-shaped light-blocking regions, and the light-transmitting regions and the light-blocking regions are arranged alternately along the first direction. The controller sequentially assigns the first image or the second image to n sub-pixels arranged according to the tilt angle of the parallax barrier with respect to the second direction. When the aperture ratio x of the parallax barrier is such that m is an integer of 0 or more and less than n, x = 0.5 + m / 2n and The controller causes sub-pixels observed by one of the first eye and the second eye across one end of the light-transmitting region and sub-pixels observed by one of the first eye and the second eye across the other end of the light-transmitting region among the n sub-pixels to display a low-luminance image with the luminance equally reduced, and the number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region. A three-dimensional display device.

[0197] (2) When the tilt angle θ with respect to the second direction of the boundary between the light-transmitting region and the light-blocking region on the display surface is such that the size along the first direction of the sub-pixel on the display surface is Hp, the size along the second direction of the sub-pixel on the display surface is Vp, and a and b are natural numbers, tan θ = (a × Hp) / (b × Vp), or tan θ = 0 The three-dimensional display device according to configuration (1), which satisfies the above.

[0198] (3) The tilt angle θ tan θ = (a × Hp) / (b × Vp) The three-dimensional display device according to configuration (2), which satisfies the above, and a and b are different natural numbers.

[0199] (4) The number of sub-pixels for displaying the low-luminance image, observed across one end of the light-transmitting region, is at least p, where p satisfies 1 ≦ p ≦ a + b - 1 The three-dimensional display device according to configuration (2) or (3).

[0200] (5) The controller causes the sub-pixels displaced by (n + m) sub-pixels to display the low-luminance image, in the three-dimensional display device according to any one of configurations (1) to (4).

[0201] (6) When the user is at the proper viewing position, the display surface has binocular visible regions observed by both the first eye and the second eye on one end side and the other end side of the light-transmitting region, The controller causes a black image to be displayed on at least m sub-pixels among the sub-pixels included in the binocular visible region on one end side, and at least m sub-pixels among the sub-pixels included in the binocular visible region on the other end side, in the three-dimensional display device according to any one of configurations (1) to (5).

[0202] (7) The tilt angle θ satisfies tanθ = (a × Hp) / (b × Vp) where a and b are different natural numbers, When the user is at the proper viewing position, the display surface has binocular visible regions observed by both the first eye and the second eye on one end side and the other end side of the light-transmitting region, The controller causes a black image to be displayed on at least m sub-pixels among the sub-pixels included in the binocular visible region on one end side, and at least m sub-pixels among the sub-pixels included in the binocular visible region on the other end side, in the three-dimensional display device according to configuration (2).

[0203] (8) The tilt angle θ satisfies tanθ = Hp / Vp and When the user is at the viewing position, the display surface has binocular visible regions observed by both the first eye and the second eye on one end side and the other end side of the light-transmitting region. The controller causes a black image to be displayed on (m + 1) sub-pixels among the sub-pixels included in the binocular visible region on one end side and (m + 1) sub-pixels among the sub-pixels included in the binocular visible region on the other end side. The three-dimensional display device according to configuration (2).

[0204] (9) When the user is not at the viewing position, the display surface has a binocular visible region observed by both the first eye and the second eye on one end side of the light-transmitting region, and the number of sub-pixels included in the binocular visible region increases as the distance between the user and the viewing position increases. The controller causes a black image to be displayed on k (k is a natural number greater than m) sub-pixels among the sub-pixels included in the binocular visible region. The three-dimensional display device according to any one of configurations (1) to (8).

[0205] (10) When the sub-pixels for displaying the black image and the sub-pixels for displaying the low-luminance image are the same sub-pixels, the controller causes a black image to be displayed on the sub-pixels. The three-dimensional display device according to any one of configurations (6) to (9).

Explanation of Reference Numerals

[0206] 1 Detection device 2 Three-dimensional display device 3 Position acquisition unit 4 Irradiator 5 Display panel 6 Parallax barrier 7 Controller 10 Moving body 51 Active area 51a Visible region 51aL Left visible region 51aR Right visible region 51aLR Binocular visible region 51bL Left invisible region 51bR Right non-visible area 51bLR Both-eyes non-visible area 52 Black matrix 61 Light-shielding surface (light-shielding area) 62, 62a Light-transmitting area 62b End line 70 Visible area 71A Optical path 71B Optical path 100 3D display system 400 Head-up display system 410 Optical member 420 Projection member 430 Projection surface 440 Optical path 450 Virtual image

Claims

1. A display panel having a display surface including a plurality of sub-pixels arranged along a first direction and a second direction intersecting the first direction; A parallax barrier that defines a ray direction of image light emitted from the display surface; A position acquisition unit that acquires the position of at least one of the first eye and the second eye of a user; A controller that synthesizes a mixed image including a first image and a second image having a parallax with respect to the first image, which are to be displayed on the display surface, based on the position of at least one of the first eye and the second eye acquired by the position acquisition unit; and The parallax barrier has a plurality of strip-shaped light-transmitting regions and a plurality of strip-shaped light-blocking regions, and the light-transmitting regions and the light-blocking regions are alternately arranged along the first direction, The controller sequentially assigns the first image or the second image to n sub-pixels arranged according to the tilt angle of the parallax barrier with respect to the second direction, When the aperture ratio x of the parallax barrier is such that m is an integer of 0 or more and less than n, x = 0.5 + m / 2n and The controller causes a low-luminance image with the luminance equally reduced to be displayed on sub-pixels that are observed by one of the first eye and the second eye across one end of the light-transmitting region and sub-pixels that are observed by one of the first eye and the second eye across the other end of the light-transmitting region among the n sub-pixels, and the number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region. A three-dimensional display device.

2. When the tilt angle θ of the boundary between the light-transmitting region and the light-blocking region on the display surface with respect to the second direction is such that the size of the sub-pixel along the first direction on the display surface is Hp, the size of the sub-pixel along the second direction on the display surface is Vp, and a and b are natural numbers, tan θ = (a × Hp) / (b × Vp), or tan θ = 0 The three-dimensional display device according to claim 1, which satisfies the above.

3. The tilt angle θ satisfies tan θ = (a × Hp) / (b × Vp) where a and b are different natural numbers from each other. The three-dimensional display device according to claim 2.

4. The number of sub-pixels displaying the low-luminance image observed across one end of the light-transmitting region is at least p, and p is 1 ≤ p ≤ a + b - 1 The three-dimensional display device according to claim 2 or 3, which satisfies

5. The three-dimensional display device according to any one of claims 1 to 3, wherein the controller causes the sub-pixels obtained by displacing the low-luminance image by (n + m) sub-pixels to be displayed.

6. When the user is at the fixation position, the display surface has binocular visible regions observed by both the first eye and the second eye on both the one end side and the other end side of the light-transmitting region, The three-dimensional display device according to any one of claims 1 to 3, wherein the controller causes a black image to be displayed on at least m sub-pixels among the sub-pixels included in the binocular visible region on the one end side and at least m sub-pixels among the sub-pixels included in the binocular visible region on the other end side.

7. The tilt angle θ satisfies tan θ = (a × Hp) / (b × Vp) where a and b are different natural numbers, When the user is at the fixation position, the display surface has binocular visible regions observed by both the first eye and the second eye on both the one end side and the other end side of the light-transmitting region, The three-dimensional display device according to claim 2, wherein the controller causes a black image to be displayed on at least m sub-pixels among the sub-pixels included in the binocular visible region on the one end side and at least m sub-pixels among the sub-pixels included in the binocular visible region on the other end side.

8. The tilt angle θ satisfies tan θ = Hp / Vp and When the user is at the fixation position, the display surface has binocular visible regions observed by both the first eye and the second eye on both the one end side and the other end side of the light-transmitting region, The three-dimensional display device according to claim 2, wherein the controller causes a black image to be displayed on (m + 1) sub-pixels among the sub-pixels included in the binocular visible region on the one end side and (m + 1) sub-pixels among the sub-pixels included in the binocular visible region on the other end side.

9. When the user is not at the fixation position, the display surface has a binocular visible region observed by both the first eye and the second eye on the one end side of the light-transmitting region, and the number of sub-pixels included in the binocular visible region increases as the distance between the user and the fixation position increases. The 3D display device according to any one of claims 1 to 3, wherein the controller causes a black image to be displayed on k (k is a natural number greater than m) sub-pixels among the sub-pixels included in the binocular visible region.

10. The 3D display device according to claim 6, wherein when the sub-pixel for displaying the black image and the sub-pixel for displaying the low-luminance image are the same sub-pixel, the controller causes the black image to be displayed on the sub-pixel.

11. A display panel having a display surface including a plurality of sub-pixels arranged along a first direction and a second direction intersecting the first direction, A parallax barrier that defines a light ray direction of image light emitted from the display surface, A position acquisition unit that acquires the position of at least one of a user's first eye and second eye, An optical member that causes the user to visually recognize the image light emitted from the display surface as a virtual image, A controller that synthesizes a mixed image including a first image and a second image having a parallax with respect to the first image, which are to be displayed on the display surface, based on the position of at least one of the first eye and the second eye acquired by the position acquisition unit, The parallax barrier has a plurality of strip-shaped light-transmitting regions and a plurality of strip-shaped light-blocking regions, and the light-transmitting regions and the light-blocking regions are alternately arranged along the first direction, The controller continuously assigns the first image or the second image to n sub-pixels arranged according to an inclination angle of the parallax barrier with respect to the second direction, When the aperture ratio x of the parallax barrier is such that m is an integer of 0 or more and less than n, x = 0.5 + m / 2n and The controller displays a low-luminance image with the luminance equally reduced on the sub-pixels observed by one of the first eye and the second eye across one end of the light-transmitting region and the sub-pixels observed by the one of the first eye and the second eye across the other end of the light-transmitting region among the n sub-pixels, and the number of sub-pixels for displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region. A head-up display system.

12. A display panel having a display surface including a plurality of sub-pixels arranged along a first direction and a second direction intersecting the first direction, A parallax barrier that defines a light ray direction of image light emitted from the display surface, A position acquisition unit that acquires the position of at least one of the user's first eye and second eye; An optical member that causes the image light emitted from the display surface to be visually recognized by the user as a virtual image; A controller that synthesizes a mixed image including a first image and a second image having a parallax with respect to the first image, the mixed image being displayed on the display surface based on the position of at least one of the first eye and the second eye acquired by the position acquisition unit; and The parallax barrier has a plurality of strip-shaped light-transmitting regions and a plurality of strip-shaped light-blocking regions, and the light-transmitting regions and the light-blocking regions are arranged alternately along the first direction; The controller continuously assigns the first image or the second image to n sub-pixels arranged according to the tilt angle of the parallax barrier with respect to the second direction; When the aperture ratio x of the parallax barrier is such that m is an integer greater than or equal to 0 and less than n, x = 0.5 + m / 2n where; The controller displays a low-luminance image with the luminance equally reduced on the sub-pixels observed by one of the first eye and the second eye across one end of the light-transmitting region and the sub-pixels observed by one of the first eye and the second eye across the other end of the light-transmitting region among the n sub-pixels, and the number of sub-pixels displaying the low-luminance image is the same on one end side and the other end side of the light-transmitting region. A moving body provided with a head-up display system.

Images