Video display device

Abstract

This video display device comprises: a display that displays, on a display surface, a first image to be visually recognized by a first eye and a second image to be visually recognized by a second eye; an optical element that limits a first eye position in which the first image can be visually recognized and a second eye position in which the second image can be visually recognized; a position acquisition unit that acquires the first eye position and the second eye position; and a display control unit that determines a first image display pixel range and a second image display pixel range by using the first eye position and the second eye position each independently, and controls the display so that the first image is allocated to pixels included in the first image display pixel range and the second image is allocated to pixels included in the second image display pixel range. The display control unit determines a both-eye overlapping range that can be visually recognized by both the first eye and the second eye in the first image display pixel range and the second image display pixel range, and, upon determining that there is the both-eye overlapping range, controls the display so as to decrease luminance with respect to one or more pixels included in the both-eye overlapping range.

Description

Video display device

[0001] The present invention relates to an image display device. This application claims priority to Japanese Patent Application No. 2022-198604, filed on December 13, 2022, the contents of which are incorporated herein by reference.

[0002] Research and development has been progressing on displays that allow viewers to view stereoscopic images without using 3D glasses, 3D goggles, etc. One example of such a display is the 3D display device disclosed in Patent Document 1. Research and development has also been progressing on multi-viewpoint displays that allow multiple viewers to view different images when the viewers view the display from different positions.

[0003] Japanese Patent Application Laid-Open No. 2022-020434

[0004] The above-mentioned three-dimensional display device can provide appropriate stereoscopic vision even when the observer moves, as long as the interocular distance between the observers is equal to the average human interocular distance and the observer's eyes are parallel to the display surface. However, there is a possibility that appropriate stereoscopic vision cannot be provided for observers who do not meet these conditions. Furthermore, the above-mentioned multi-viewpoint display may not be able to provide appropriate viewing for each of the multiple observers if the distance between the multiple observers is not equal to a predetermined distance or if the multiple observers are not parallel to the display surface.

[0005] The present invention has been made in consideration of the above circumstances, and its object is to provide an image display device that can improve the visibility of an image even when the observer's eyes are not positioned in a predetermined position.

[0006] One aspect of the present invention is a display having a display surface including a plurality of pixels, the display surface displaying a first image to be viewed by a first eye and a second image to be viewed by a second eye; an optical element limiting a first eye position, which is the position of the first eye at which the first image can be viewed, and a second eye position, which is the position of the second eye at which the second image can be viewed; a position acquisition unit acquiring the first eye position and the second eye position; and a display unit that independently uses the first eye position and the second eye position to determine a first image display pixel range for displaying the first image based on the first eye position and to display the second image based on the second eye position. and a display control unit that determines a second image display pixel range in which to display the first image, and controls the display so that the first image is assigned to pixels included in the first image display pixel range and the second image is assigned to pixels included in the second image display pixel range, wherein the display control unit determines a binocular overlap range in the first image display pixel range and the second image display pixel range that is visible to both the first eye and the second eye, and when it determines that a binocular overlap range exists, controls the display to reduce the brightness of one or more pixels included in the binocular overlap range.

[0007] According to the present invention, it is possible to obtain an effect that the visibility of an image can be improved even when the observer's eyes are not positioned at a predetermined position.

[0008] FIG. 1 is a diagram illustrating an example of a stereoscopic display device according to an embodiment. FIG. 2 is a flowchart illustrating an example of a procedure in a design stage of a method for controlling a stereoscopic display device according to an embodiment. FIG. 3 is an explanatory diagram illustrating a barrier end face overlap pixel range according to an embodiment. FIG. 4 is an explanatory diagram illustrating an example of a method for determining a brightness reduction method according to an embodiment. FIG. 5 is a flowchart illustrating an example of a procedure in an operation stage of a method for controlling a stereoscopic display device according to an embodiment. FIG. 6 is an explanatory diagram illustrating an example of a method for controlling a stereoscopic display device according to an embodiment. FIG. 7 is an explanatory diagram illustrating an example of a method for controlling a stereoscopic display device according to an embodiment. FIG. 8 is an explanatory diagram illustrating an example of a method for controlling a stereoscopic display device according to an embodiment. FIG. 9 is an explanatory diagram illustrating an example of a method for controlling a stereoscopic display device according to an embodiment. FIG. 10 is an explanatory diagram illustrating an example of a method for controlling a stereoscopic display device according to an embodiment. FIG. 1 is an explanatory diagram for explaining a luminance uniformization process according to an embodiment. FIG. 2 is an explanatory diagram for explaining a luminance uniformization process according to an embodiment. FIG. 3 is a diagram showing an example of a stereoscopic display device according to a modified example of an embodiment. FIG. 4 is an explanatory diagram for explaining an example of a control method for a stereoscopic display device according to a modified example of an embodiment. FIG. 5 is an explanatory diagram for explaining an example of a control method for a stereoscopic display device according to a modified example of an embodiment. FIG. 6 is an explanatory diagram for explaining an example of a control method for a stereoscopic display device according to a modified example of an embodiment.

[0009] (Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a diagram showing an example of a stereoscopic display device according to an embodiment. As shown in Fig. 1, the stereoscopic display device 100 includes a display 101, an optical element 102, a display control unit 103, a storage unit 104, and a position acquisition unit 105. In the following description, three-dimensional Cartesian coordinates defined by the X-axis, Y-axis, and Z-axis shown in Fig. 1 will be used as appropriate.

[0010] The display 101 has a display surface including a plurality of pixels arranged along a first direction and a second direction. The first direction is, for example, the X direction shown in FIG. 1 . The second direction is a direction intersecting the first direction, for example, the Y direction shown in FIG. 1 . The display 101 is parallel to the XY plane and displays a pair of a right-eye image MR and a left-eye image ML on the display surface, on a plane perpendicular to the Z axis, for every n pixels (n is a positive integer greater than or equal to 2m, and m is a positive integer). Each of the right-eye image MR and the left-eye image ML has a size of m pixels. The right-eye image MR is an image to be viewed by the right eye ER of the observer P. The left-eye image ML is an image to be viewed by the left eye EL of the observer P. The pair of the right-eye image MR and the left-eye image ML is a parallax image. When the pair of the right-eye image MR and the left-eye image ML is correctly viewed by the right eye ER and the left eye EL of the observer P, normal stereoscopic vision can be provided to the observer P. 1 is for convenience of explanation. The display 101 is, for example, a self-luminous display.

[0011] The pixels arranged on the display surface of the display 101 correspond to any one of the colors R (Red), G (Green), and G (Blue). One pixel may be configured by a set of three pixels of R, G, and B. When one pixel is configured by a set of three pixels of R, G, and B, the pixel corresponding to any one of the colors of R, G, and B is also referred to as a subpixel. Therefore, one pixel may be configured by a set of three subpixels of R, G, and B. In this case, the first direction is, for example, the direction in which multiple subpixels that make up one pixel are arranged. The second direction is, for example, the direction in which subpixels corresponding to the same color are arranged.

[0012] The optical element 102 is, for example, a parallax barrier having a light-blocking region and a transmissive region. The optical element 102 limits the positions of the right eye ER and the left eye EL by the light-blocking region and the transmissive region. The optical element 102 is, for example, a parallax barrier having linear slits inclined at a predetermined angle (tilt angle) with respect to the X-axis and the Y-axis. In this embodiment, a parallax barrier having one opening for n pixels is used as an example of the optical element 102. The optical element 102 limits the positions of the right eye ER and the left eye EL at which the right-eye image MR and the left-eye image ML can be viewed, respectively. Also, as shown in FIG. 1 , in order for the right eye ER and the left eye EL of the viewer P to view the entire screen with normal stereoscopic vision, the viewer P needs to view from a position that is an optimal viewing distance OVD away from the optical element 102. The openings are an example of a transmissive region. The areas of the parallax barrier other than the openings are an example of a light-blocking region.

[0013] The detection device 3 detects the positions of the right eye ER and the left eye EL of the viewer P and outputs the detected positions to the stereoscopic display device 100. Here, the detection device 3 detects the positions of the right eye ER and the left eye EL individually. The detection device 3 includes a sensor such as a camera. For example, the detection device 3 includes a camera and detects the positions of the right eye ER and the left eye EL from an image of the viewer P's face captured by the camera. The detection device 3 outputs the detected three-dimensional coordinates of the positions of the right eye ER and the left eye EL of the viewer P to the stereoscopic display device 100. Note that the detection device 3 may be included in the stereoscopic display device 100 or may be a device separate from the stereoscopic display device 100. The detection device 3 is an example of a viewpoint detection unit that detects the first eye position and the second eye position individually.

[0014] The position acquisition unit 105 acquires the positions of the right eye ER and the left eye EL of the observer P. Specifically, the position acquisition unit 105 acquires the three-dimensional coordinates of the positions of the right eye ER and the left eye EL of the observer P, which are input from the detection device 3 to the stereoscopic display device 100. The position acquisition unit 105 acquires the positions of the right eye ER and the left eye EL, which are individually detected by the detection device 3.

[0015] The display control unit 103 determines the right-eye image display pixel range of the right-eye image MR to be assigned to the position of the observer P's right eye ER and the left-eye image display pixel range of the left-eye image ML to be assigned to the position of the left eye EL, and controls the display 101 to display the right-eye image MR in the right-eye image display pixel range and the left-eye image ML in the left-eye image display pixel range.

[0016] Note that allocating an image to the position of the eye of observer P means allocating the image to pixels included in the range visible to that eye on the display surface of display 101. Display control unit 103 uses the positions of the right eye ER and the left eye EL independently to determine a right-eye image display pixel range for displaying the right-eye image MR based on the position of the right eye ER, and determines a left-eye image display pixel range for displaying the left-eye image ML based on the position of the left eye EL, and controls display 101 so that the right-eye image MR is allocated to pixels included in the right-eye image display pixel range, and the left-eye image ML is allocated to pixels included in the left-eye image display pixel range. Here, allocating an image to a pixel means assigning a luminance value based on the image to the pixel.

[0017] The display control unit 103 also determines a left-right overlapping range that can be seen by both the right eye ER and the left eye EL of the observer P in the right-eye image display pixel range and the left-eye image display pixel range, and if the determination determines that there is a left-right overlapping range, controls the display 101 to reduce the luminance of one or more pixels included in the left-right overlapping range. An example of a method for reducing luminance is black display. Note that the right eye ER is an example of the first eye, and the left eye EL is an example of the second eye. The left-right overlapping range is also an example of a range overlapping both eyes.

[0018] The storage unit 104 stores various types of data and is accessed by the display control unit 103.

[0019] The display control unit 103 is realized, for example, by a display control program stored in a storage medium being read and executed by a CPU (Central Processing Unit) or the like. Alternatively, the display control unit 103 may be realized by hardware including circuitry such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit). Alternatively, the display control unit 103 may be realized by a combination of software and hardware. These pieces of hardware may be integrated into one unit or may be separated into multiple units.

[0020] The storage unit 104 may also be configured as a non-volatile memory such as a hard disk device, a magneto-optical disk device, or a flash memory, a read-only recording medium such as a CD-ROM, a volatile memory such as a DRAM (Dynamic Random Access Memory), or a combination of these.

[0021] An example of a control method for the stereoscopic display device 100 according to this embodiment will be described below.

[0022] The control method for the stereoscopic display device 100 according to this embodiment has a design stage and an operation stage. The design stage is performed when the stereoscopic display device 100 is designed. The operation stage is performed when the viewer P uses the stereoscopic display device 100.

[0023] [Design Stage] The design stage of the control method for the stereoscopic display device 100 according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a flowchart showing an example of the procedure of the design stage of the control method for the stereoscopic display device according to this embodiment.

[0024] (Step S101) The number of pixels m, which is the size of the right-eye image MR and the left-eye image ML, is determined. A method for determining this number of pixels m will now be described. On the display surface of the display 101, regions (pixel regions) corresponding to n pixels, each of which is observed at the center of the X-axis direction of the opening of the optical element 102 as viewed from an observer P at the optimal viewing distance OVD, are continuously present at equal intervals in the X-axis direction. In this case, m≦n / 2, and the width A of the m pixel regions in the X-axis direction is A≒E, where E is the average human interocular distance. From this relationship, the number of pixels m can be calculated by dividing the average human interocular distance E by the design width of one pixel region in the X-axis direction of the display 101. The relationship m≦n / 2 indicates that some of the n pixels may be completely invisible to the observer P at the optimal viewing distance OVD. In FIG. 1, pixels 0 through 1 are shown as these completely invisible pixels. Hereinafter, a pixel region on the display surface of the display 101 may be simply referred to as a pixel. When the pixel region is simply referred to as a pixel, the pixel refers to the sub-pixel described above.

[0025] (Step S102) The number of pixels (number of pixels per eye) q in the range of pixels observed by one eye (one-eye pixel range) is determined from the designed aperture ratio of the optical element 102. The aperture ratio of the parallax barrier serving as the optical element 102 is defined by the formula "(m-k) / n, k<m". k is the number of pixels out of m pixels that cannot be seen by the observer P at the optimum observation distance OVD. When "k=0" and "2m=n", the "aperture ratio=50%". From the above aperture ratio, the number of pixels per eye q is "q=m-k". Note that although "k≧0" is usually true, "k<0" may also be true.

[0026] (Step S103) Of the n pixels on the display surface of the display 101, the number r of pixels in the range that overlaps with the end surface of the parallax barrier serving as the optical element 102 (barrier end surface overlapping pixel range) as seen from the viewer P is determined. FIG. 3 is an explanatory diagram of the barrier end surface overlapping pixel range according to this embodiment. FIG. 3 shows pixels 200 in the barrier end surface overlapping pixel range that overlap with the barrier end surface 210 of the parallax barrier serving as the optical element 102. The pixels 200 in the barrier end surface overlapping pixel range are pixels that can be seen by both the right eye ER and the left eye EL of the viewer P. Therefore, the barrier end surface overlapping pixel range may be seen by both the right eye and the left eye, which can cause crosstalk. For this reason, the barrier end surface overlapping pixel range is a range in which it is preferable to perform the luminance reduction process described below. The number r of pixels in the barrier end surface overlapping pixel range is calculated using the formula "r = a + b - 1" when the formula is "tan θ = a × Hp / (b × Vp)." θ is the tilt angle of the parallax barrier. Here, the tilt angle θ of the parallax barrier is an angle equal to or greater than 0° and less than 90°, and when the tilt angle θ of the parallax barrier is greater than 0° (θ>0°), in the above formula, the length of the pixel on the display surface of the display 101 in the X direction is Hp, the length of the pixel on the display surface in the Y direction is Vp, and a and b are natural numbers.

[0027] As described above, the display control unit 103 determines the range (in this embodiment, the barrier end surface overlap pixel range) that is the end (in this embodiment, the barrier end surface 210) of the range observed from the first eye position (in this embodiment, the position of the right eye ER) through the optical element 102 and that is the end (in this embodiment, the barrier end surface 210) of the range observed from the second eye position (in this embodiment, the position of the left eye EL) through the optical element 102 as the both-eye overlap range (in this embodiment, the left-right overlap range).

[0028] (Step S104) A brightness reduction method is determined, and the determined brightness reduction method is stored in the storage unit 104. The method for determining the brightness reduction method will be described below. Of the number r of pixels in the barrier end surface overlapping pixel range, the number p of pixels that may be subjected to brightness reduction processing is determined. The brightness reduction processing is, for example, black display. FIG. 4 is an explanatory diagram of an example of a method for determining the brightness reduction method. In FIG. 4, the interior of the barrier opening is between the barrier end surface 210a and the barrier end surface 210b of the parallax barrier serving as the optical element 102. FIG. 4 shows pixels 211a, 212a, and 213a in the barrier end surface overlapping pixel range on the barrier end surface 210a, and pixels 211b, 212b, and 213b in the barrier end surface overlapping pixel range on the barrier end surface 210b. In the example of FIG. 4, r=3. Furthermore, in the example of FIG. 4, the aperture ratio is 50%, m=9, and q=9. When all the pixels in the barrier edge overlap pixel range are displayed in black, for example, p = r = 3. Note that p≦r. Furthermore, when r is an even number, p may be an even number, and when r is an odd number, p may be an odd number. For example, when r is an even number, p may be two, and when r is an odd number, p may be one.

[0029] Next, the number of evaluation pixels inside the barrier opening is set to "q + p," and the number of central pixels in the right-eye image MR and the left-eye image ML is determined. If the number of evaluation pixels "q + p" is an even number, the number of central pixels is two. On the other hand, if the number of evaluation pixels "q + p" is an odd number, the number of central pixels is one. For example, if "p = 1" is set for "r = 3" in FIG. 4, the number of evaluation pixels is "q + p = 9 + 1 = 10," which is an even number, so the number of central pixels is two.

[0030] In this embodiment, a right-eye evaluation pixel range with "q+p" number of evaluation pixels and a left-eye evaluation pixel range with "q+p" number of evaluation pixels are used to determine the right-eye overlap range that can be viewed by both the right eye ER and the left eye EL of the observer P in the right-eye image display pixel range and the left-eye image display pixel range. In the operation stage described below, the positions of the right eye ER and the left eye EL of the observer P are acquired, and a right-eye evaluation pixel range with "q+p" number of evaluation pixels to be assigned to the acquired right-eye ER position and a left-eye evaluation pixel range with "q+p" number of evaluation pixels to be assigned to the acquired left-eye EL position are determined, and the overlap range (evaluation overlap range) of the determined right-eye evaluation pixel range and left-eye evaluation pixel range is determined. In this design stage, a luminance reduction method for the evaluation overlap range where the right-eye evaluation pixel range and left-eye evaluation pixel range overlap is determined, and the determined luminance reduction method is stored in the storage unit 104.

[0031] A method for reducing brightness in the evaluation overlap range will be described. First, the brightness of the evaluation overlap range is reduced. When the number of pixels in the evaluation overlap range is less than or equal to a predetermined first threshold (e.g., 2p), the brightness of at least one pixel (barrier edge brightness-reduced pixel) among the p pixels in the barrier edge overlap pixel range is reduced. Furthermore, as a moiré prevention process, the brightness of pixels that are separated from the at least one barrier edge brightness-reduced pixel by a single eye's number q of pixels is also reduced. On the other hand, when the number of pixels in the evaluation overlap range for one eye exceeds a predetermined second threshold (e.g., 2p), only the brightness of the excess number of pixels is reduced, and no moiré prevention process is performed. This is because the number of pixels exceeding the second threshold are not present on the end face of the parallax barrier and therefore do not cause moiré due to the barrier edge. One example of a method for reducing brightness is to display black.

[0032] The above-described moire prevention processing needs to be performed only when it is determined that moire will occur due to the design of the stereoscopic display device 100.

[0033] Note that if the number of pixels whose brightness is reduced by displaying black or the like on the display surface of the display 101 using the above-described brightness reduction method increases, uneven brightness on the display surface of the display 101 becomes noticeable, or the display surface of the display 101 becomes dark overall. For example, when reducing the brightness of pixels whose number exceeds the second threshold, the number of pixels on which the brightness reduction process is performed may differ depending on the state of the observer P. This may result in noticeable uneven brightness on the display surface of the display 101. To address such cases, a brightness uniformization process is set to be performed to uniformize brightness across the entire display surface of the display 101.

[0034] The above-described brightness reduction methods are determined for all possible cases in the design of the stereoscopic display device 100 and are stored in the storage unit 104 .

[0035] [Operation Stage] The operation stage of the control method for the stereoscopic display device 100 according to this embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of the procedure of the operation stage of the control method for the stereoscopic display device according to this embodiment.

[0036] (Step S201) The position acquisition unit 105 acquires the three-dimensional coordinates of the positions of the right eye ER and the left eye EL of the viewer P input from the detection device 3 to the stereoscopic display device 100.

[0037] (Step S202) The display control unit 103 determines a right-eye evaluation pixel range of "q+p" evaluation pixels to be assigned to the position of the right eye ER and a left-eye evaluation pixel range of "q+p" evaluation pixels to be assigned to the position of the left eye EL, based on the three-dimensional coordinates of the position of the right eye ER and the three-dimensional coordinates of the position of the left eye EL of the observer P acquired by the position acquisition unit 105. Here, the display control unit 103 determines the right-eye evaluation pixel range and the left-eye evaluation pixel range independently using the three-dimensional coordinates of the position of the right eye ER and the three-dimensional coordinates of the position of the left eye EL of the observer P.

[0038] (Step S203) The display control unit 103 determines the range where the right-eye evaluation pixel range and the left-eye evaluation pixel range determined in step S202 overlap (evaluation overlap range). The evaluation overlap range changes depending on the actual interocular distance E' of the observer P and the observation state of the observer P (posture of the observer P, such as tilt of the head or upper body). If the determination in step S203 shows that there is an evaluation overlap range (step S203, YES), the process proceeds to step S205. On the other hand, if there is no evaluation overlap range (step S203, NO), the process proceeds to step S204.

[0039] (Step S204) If it is determined in step S203 that there is no evaluation overlap range, the display control unit 103 controls the display 101 to display the right-eye image MR using one-eye pixel range (number of pixels "q") including the center pixel of the right-eye evaluation pixel range (number of pixels "q+p") as the right-eye image display pixel range, and to display the left-eye image ML using one-eye pixel range (number of pixels "q") including the center pixel of the left-eye evaluation pixel range (number of pixels "q+p") as the left-eye image display pixel range. Then, the process proceeds to step S207. In this case, the brightness reduction process is not performed.

[0040] As described above, the display control unit 103 determines whether or not there is an overlap range between the eyes (in this embodiment, the evaluation overlap range), and if it determines that there is no overlap range between the eyes, it determines the area that is visible from the first eye position (in this embodiment, the position of the right eye ER) but not from the second eye position (in this embodiment, the position of the left eye EL) as the first image display pixel range (in this embodiment, the right eye image display pixel range), determines the area that is visible from the second eye position but not from the first eye position as the second image display pixel range (in this embodiment, the left eye image display pixel range), and controls the display 101 so that the first image (in this embodiment, the right eye image MR) is assigned to the pixels included in the first image display pixel range, and the second image (in this embodiment, the left eye image ML) is assigned to the pixels included in the second image display pixel range.

[0041] (Step S205) If it is determined in step S203 that there is an evaluation overlap range, the display control unit 103 acquires from the storage unit 104 a brightness reduction method corresponding to the determination result.

[0042] (Step S206) The display control unit 103 controls the display 101 to display the right-eye image MR by setting the one-eye pixel range (number of pixels "q") including the center pixel of the right-eye evaluation pixel range (number of pixels "q+p") as the right-eye image display pixel range, and to display the left-eye image ML by setting the one-eye pixel range (number of pixels "q") including the center pixel of the left-eye evaluation pixel range (number of pixels "q+p") as the left-eye image display pixel range, and also controls the display 101 using the brightness reduction method obtained from the memory unit 104.

[0043] (Step S207) The display control unit 103 determines whether or not there is partial non-uniformity in the brightness reduction process across the entire display surface of the display 101. If the result of this determination indicates that there is partial non-uniformity in the brightness reduction process, the process proceeds to step S208; if not, the process of FIG. 5 ends.

[0044] (Step S208) The display control unit 103 executes a predetermined luminance uniformization process, and then ends the process in FIG.

[0045] Here, the luminance uniformization process will be described. As described in the design stage above, for example, when the luminance of pixels exceeding the second threshold is reduced, the number of pixels on the display surface of the display 101 that are subjected to the luminance uniformization process may differ depending on the state of the viewer P. For example, as illustrated in FIG. 20 , the viewer P's eyes are not parallel to the display surface of the display. In such a case, as illustrated in FIG. 21 , the number of pixels on the display surface of the display 101 that are subjected to the luminance uniformization process may differ, resulting in a difference in the number of pixels displayed in each region (number of pixels n) on the display surface of the display. For example, in the first region, out of the "8" number of pixels observed by both eyes of the viewer P, the display number is "4" due to black display as the luminance uniformization process, whereas in the second region, out of the "8" number of pixels observed by both eyes of the viewer P, the display number is "2" due to black display as the luminance uniformization process. This results in partial luminance uniformity across the entire display surface of the display 101, and a luminance uniformization process is performed to address this issue.

[0046] As a brightness equalization process, for example, the display control unit 103 may reduce the brightness of pixels that exist in areas of the display surface of the display 101 that are brighter than other areas by a certain amount, in order to uniformly adjust the brightness of the display surface of the display 101.

[0047] Furthermore, when the proportion of pixels whose luminance is reduced on the display surface of the display 101 is equal to or greater than a certain level, the display control unit 103 may perform control to increase the luminance of the entire display surface of the display 101. An example of control to increase the luminance of the entire display surface of the display 101 is to increase the luminance of a backlight that illuminates the display surface of the display 101.

[0048] 6 to 19 are explanatory diagrams for explaining examples of a control method for the stereoscopic display device according to this embodiment. Examples of a control method for the stereoscopic display device 100 will be described with reference to FIGS. 6 to 19. Here, examples of the design aperture ratio of the parallax barrier serving as the optical element 102 are given, with examples of 50% and 25%. Also, here, black display is performed as an example of brightness reduction processing.

[0049] 6 to 13 are examples in which the parallax barrier serving as the optical element 102 has a designed aperture ratio of 50%. In the examples of Fig. 6 to 13, n = 16, m = 8, k = 0, q = 8, p = 2, p + q = 10 (even numbers), number of central pixels = 2, first threshold = 2p = 4, and second threshold = 2p = 4. These values ​​are determined when the stereoscopic display device 100 is designed.

[0050] Example 1-1 in FIGS. 6 and 7 illustrates a case in which the actual interocular distance E' of the observer P is equal to the average interocular distance E of a person during operation of the stereoscopic display device 100. FIG. 6 is an explanatory diagram illustrating how pixels on the display surface of the display 101 appear to the observer P in Example 1-1. On the right eye side of FIG. 6, the pixels that can be viewed by the right eye ER of the observer P due to the restriction imposed by the parallax barrier serving as the optical element 102 are the 5th to 14th pixels (10 pixels). On the left eye side of FIG. 6, the pixels that can be viewed by the left eye EL of the observer P due to the restriction imposed by the parallax barrier serving as the optical element 102 are the 13th to 15th pixels and the 0th to 6th pixels (10 pixels). The 5th to 6th pixels and the 13th to 14th pixels are pixels that can be viewed by both eyes of the observer P. For this reason, the 5th to 6th pixels and the 13th to 14th pixels are displayed in black.

[0051] 7 is an explanatory diagram for explaining the operation of the display control unit 103 in Example 1-1. Based on the positions of the right eye ER and the left eye EL of the viewer P acquired by the position acquisition unit 105, the display control unit 103 separately determines a right-eye evaluation pixel range "5th to 14th pixels" with the number of evaluation pixels "q + p = 10" to be assigned to the position of the right eye ER, and a left-eye evaluation pixel range "13th to 15th, 0th to 6th pixels" with the number of evaluation pixels "q + p = 10" to be assigned to the position of the left eye EL. Next, the display control unit 103 determines the evaluation overlap ranges "5th to 6th pixels" and "13th to 14th pixels" where the right-eye evaluation pixel range "5th to 14th pixels" and the left-eye evaluation pixel range "13th to 15th, 0th to 6th pixels" overlap. As a result, the display control unit 103 displays the evaluation overlap ranges "5th-6th pixels" and "13th-14th pixels" in black.

[0052] Example 1-2 in FIGS. 8 and 9 illustrates a case in which the actual interocular distance E' of the observer P is shorter than the average interocular distance E of a person during operation of the stereoscopic display device 100. As a result, as shown in FIG. 9 , the distance between the two central pixels on the right eye side and the two central pixels on the left eye side is shorter by one pixel than in Example 1-1 in FIG. 7 described above. FIG. 8 is an explanatory diagram for explaining how pixels on the display surface of the display 101 appear to the observer P in Example 1-2. On the right eye side in FIG. 8 , the pixels that can be viewed by the right eye ER of the observer P due to the limitations imposed by the parallax barrier serving as the optical element 102 are the 4th to 13th pixels (10 pixels). On the left eye side in FIG. 8 , the pixels that can be viewed by the left eye EL of the observer P due to the limitations imposed by the parallax barrier serving as the optical element 102 are the 13th to 15th pixels and the 0th to 6th pixels (10 pixels). The fourth to sixth and thirteenth pixels are pixels that can be seen by both eyes of the observer P. For this reason, the fourth to sixth and thirteenth pixels are displayed in black.

[0053] FIG. 9 is an explanatory diagram for explaining the operation of the display control unit 103 in Example 1-2. Based on the positions of the right eye ER and the left eye EL of the viewer P acquired by the position acquisition unit 105, the display control unit 103 separately determines a right-eye evaluation pixel range "pixels 4-13" with an evaluation pixel count of "q+p=10" to be assigned to the position of the right eye ER, and a left-eye evaluation pixel range "pixels 13-15, 0-6" with an evaluation pixel count of "q+p=10" to be assigned to the position of the left eye EL. Next, the display control unit 103 determines an evaluation overlap range "pixels 4-6, 13" where the right-eye evaluation pixel range "pixels 4-13" and the left-eye evaluation pixel range "pixels 13-15, 0-6" overlap. As a result, the display control unit 103 displays the evaluation overlap range "pixels 4-6, 13" in black. Here, since the number of pixels "4" in the evaluation overlap range is equal to or less than the first threshold value "2p=4", and the luminance is reduced for at least one pixel (the barrier edge surface luminance-reduced pixels "4th to 5th pixels" and "5th to 6th pixels") out of the "p=2" pixels "4th to 5th pixels" and "5th to 6th pixels" in the barrier edge surface overlap pixel range, the display control unit 103 further performs moiré prevention processing by similarly displaying the pixels "12th and 14th pixels" that are one-eye pixel number "q=8" away from the barrier edge surface luminance-reduced pixels "4th to 6th pixels" in black.

[0054] Example 1-3 in FIGS. 10 and 11 illustrates a case in which the actual interocular distance E' of the observer P is shorter than the average interocular distance E of a person during operation of the stereoscopic display device 100. As a result, as shown in FIG. 11 , the distance between the two central pixels on the right eye side and the two central pixels on the left eye side is shorter by two pixels than in Example 1-1 in FIG. 7 described above. FIG. 10 is an explanatory diagram for explaining how pixels on the display surface of the display 101 appear to the observer P in Example 1-3. On the right eye side in FIG. 10 , the pixels that can be viewed by the right eye ER of the observer P due to the limitations imposed by the parallax barrier serving as the optical element 102 are the fourth to thirteenth pixels (10 pixels). Furthermore, on the left eye side in FIG. 10 , the pixels that can be viewed by the left eye EL of the observer P due to the limitations imposed by the parallax barrier serving as the optical element 102 are the fourteenth to fifteenth pixels and the zeroth to seventh pixels (10 pixels). The fourth to seventh pixels are pixels that can be seen by both eyes of the observer P. For this reason, the fourth to seventh pixels are displayed in black.

[0055] FIG. 11 is an explanatory diagram for explaining the operation of the display control unit 103 in Example 1-3. Based on the positions of the right eye ER and the left eye EL of the viewer P acquired by the position acquisition unit 105, the display control unit 103 separately determines a right-eye evaluation pixel range "pixels 4 to 13" with an evaluation pixel count of "q + p = 10" to be assigned to the position of the right eye ER, and a left-eye evaluation pixel range "pixels 14 to 15, 0 to 7" with an evaluation pixel count of "q + p = 10" to be assigned to the position of the left eye EL. Next, the display control unit 103 determines an evaluation overlap range "pixels 4 to 7" where the right-eye evaluation pixel range "pixels 4 to 13" and the left-eye evaluation pixel range "pixels 14 to 15, 0 to 7" overlap. As a result, the display control unit 103 displays the evaluation overlap range "pixels 4 to 7" in black. Here, since the number of pixels "4" in the evaluation overlap range is equal to or less than the first threshold value "2p=4", and the luminance is reduced for at least one pixel (the barrier edge surface luminance-reduced pixels "4th to 5th pixels" and "6th to 7th pixels") out of the "p=2" pixels "4th to 5th pixels" and "6th to 7th pixels" in the barrier edge surface overlap pixel range, the display control unit 103 further performs moiré prevention processing by similarly displaying the pixels "12th to 15th pixels" that are one-eye pixel number "q=8" away from the barrier edge surface luminance-reduced pixels "4th to 7th pixels" in black.

[0056] Example 1-4 in FIGS. 12 and 13 illustrates a case in which the actual interocular distance E' of the observer P is shorter than the average interocular distance E of a person during operation of the stereoscopic display device 100. As a result, as shown in FIG. 13 , the distance between the two central pixels on the right eye side and the two central pixels on the left eye side is three pixels shorter than in Example 1-1 in FIG. 7 described above. FIG. 12 is an explanatory diagram for explaining how pixels on the display surface of the display 101 appear to the observer P in Example 1-4. On the right eye side in FIG. 12 , the pixels that can be viewed by the right eye ER of the observer P due to the limitations imposed by the parallax barrier serving as the optical element 102 are the fourth to thirteenth pixels (10 pixels). Furthermore, on the left eye side in FIG. 12 , the pixels that can be viewed by the left eye EL of the observer P due to the limitations imposed by the parallax barrier serving as the optical element 102 are the fifteenth and zeroth to eighth pixels (10 pixels). The fourth to eighth pixels are pixels that can be seen by both eyes of the observer P. For this reason, the fourth to eighth pixels are displayed in black.

[0057] FIG. 13 is an explanatory diagram for explaining the operation of the display control unit 103 in Example 1-4. Based on the positions of the right eye ER and the left eye EL of the viewer P acquired by the position acquisition unit 105, the display control unit 103 separately determines a right-eye evaluation pixel range "pixels 4-13" with an evaluation pixel count of "q+p=10" to be assigned to the position of the right eye ER, and a left-eye evaluation pixel range "pixels 15, 0-8" with an evaluation pixel count of "q+p=10" to be assigned to the position of the left eye EL. Next, the display control unit 103 determines an evaluation overlap range "pixels 4-8" where the right-eye evaluation pixel range "pixels 4-13" and the left-eye evaluation pixel range "pixels 15, 0-8" overlap. As a result, the display control unit 103 displays the evaluation overlap range "pixels 4-8" in black. Here, since the number of pixels in the evaluation overlap range "5" exceeds the second threshold "2p = 4", the display control unit 103 only reduces the brightness of the excess pixel "the sixth pixel" and does not perform moiré prevention processing. As a result, as a moiré prevention processing, the display control unit 103 also similarly displays the pixels "the 12th, 13th, 15th, and 0th pixels" that are separated by one-eye pixel number "q = 8" from the barrier edge surface brightness reduction pixels "the 4th, 5th, and 7th, 8th pixels" in black.

[0058] 14 to 19 are examples in which the designed aperture ratio of the parallax barrier serving as the optical element 102 is 25%. In the examples of Fig. 14 to 19, n = 16, m = 8, k = 4, q = 4, p = 2, p + q = 6 (even numbers), number of central pixels = 2, first threshold = 2p = 4, second threshold = 2p = 4. These values ​​are determined when the stereoscopic display device 100 is designed.

[0059] Example 2-1 in FIGS. 14 and 15 illustrates a case in which the actual interocular distance E' of the observer P is equal to the average interocular distance E of a person during operation of the stereoscopic display device 100. FIG. 14 is an explanatory diagram illustrating how pixels on the display surface of the display 101 appear to the observer P in Example 2-1. On the right eye side of FIG. 14 , the pixels that can be viewed by the right eye ER of the observer P due to the restriction imposed by the parallax barrier serving as the optical element 102 are the 7th to 12th pixels (6 pixels). On the left eye side of FIG. 14 , the pixels that can be viewed by the left eye EL of the observer P due to the restriction imposed by the parallax barrier serving as the optical element 102 are the 15th and 0th to 4th pixels (6 pixels). In Example 2-1, there are no pixels that can be viewed by both eyes of the observer P. Therefore, there are no pixels that display black.

[0060] FIG. 15 is an explanatory diagram for explaining the operation of the display control unit 103 in Example 2-1. Based on the positions of the right eye ER and the left eye EL of the viewer P acquired by the position acquisition unit 105, the display control unit 103 separately determines a right-eye evaluation pixel range "pixels 7-12" with an evaluation pixel count of "q+p=6" to be assigned to the position of the right eye ER, and a left-eye evaluation pixel range "pixels 15, 0-4" with an evaluation pixel count of "q+p=6" to be assigned to the position of the left eye EL. Next, the display control unit 103 determines that there is no evaluation overlap range, in which the right-eye evaluation pixel range "pixels 7-12" and the left-eye evaluation pixel range "pixels 15, 0-4" overlap. As a result, the display control unit 103 does not display black because there is no evaluation overlap range.

[0061] Example 2-2 in FIGS. 16 and 17 illustrates a case in which the actual interocular distance E' of the observer P is shorter than the average interocular distance E of a person during operation of the stereoscopic display device 100. As a result, as shown in FIG. 17 , the distance between the two central pixels on the right eye side and the two central pixels on the left eye side is three pixels shorter than in Example 2-1 in FIG. 15 described above. FIG. 16 is an explanatory diagram illustrating how pixels on the display surface of the display 101 appear to the observer P in Example 2-2. On the right eye side in FIG. 16 , the pixels that can be viewed by the right eye ER of the observer P due to the restriction imposed by the parallax barrier serving as the optical element 102 are the sixth to eleventh pixels (six pixels). On the left eye side in FIG. 16 , the pixels that can be viewed by the left eye EL of the observer P due to the restriction imposed by the parallax barrier serving as the optical element 102 are the first to sixth pixels (six pixels). The sixth pixel is a pixel that can be viewed by both eyes of the observer P. Therefore, the sixth pixel is displayed in black.

[0062] FIG. 17 is an explanatory diagram for explaining the operation of the display control unit 103 in Example 2-2. Based on the positions of the right eye ER and the left eye EL of the viewer P acquired by the position acquisition unit 105, the display control unit 103 separately determines a right-eye evaluation pixel range "pixels 6 to 11" with an evaluation pixel count of "q + p = 6" to be assigned to the position of the right eye ER, and a left-eye evaluation pixel range "pixels 1 to 6" with an evaluation pixel count of "q + p = 6" to be assigned to the position of the left eye EL. Next, the display control unit 103 determines an evaluation overlap range "pixel 6" where the right-eye evaluation pixel range "pixels 6 to 11" and the left-eye evaluation pixel range "pixels 1 to 6" overlap. As a result, the display control unit 103 displays the evaluation overlap range "pixel 6" in black. Here, since the number of pixels "1" in the evaluation overlap range is equal to or less than the first threshold value "2p=4" and the luminance is reduced for at least one pixel (the barrier edge surface luminance-reduced pixel "sixth pixel") out of the "p=2" pixels "sixth to seventh pixels" in the barrier edge overlap pixel range, the display control unit 103 further performs moiré prevention processing by similarly displaying the pixels "second and tenth pixels" that are one-eye pixel number "q=4" away from the barrier edge surface luminance-reduced pixel "sixth pixel" in black.

[0063] Example 2-3 in FIGS. 18 and 19 illustrates a case in which the actual interocular distance E' of the observer P is shorter than the average interocular distance E of a person during operation of the stereoscopic display device 100. As a result, as shown in FIG. 19 , the distance between the two central pixels on the right eye side and the two central pixels on the left eye side is four pixels shorter than in Example 2-1 in FIG. 15 described above. FIG. 18 is an explanatory diagram illustrating how pixels on the display surface of the display 101 appear to the observer P in Example 2-3. On the right eye side in FIG. 18 , the pixels that can be viewed by the right eye ER of the observer P due to the limitations imposed by the parallax barrier serving as the optical element 102 are the sixth to eleventh pixels (six pixels). On the left eye side in FIG. 18 , the pixels that can be viewed by the left eye EL of the observer P due to the limitations imposed by the parallax barrier serving as the optical element 102 are the second to seventh pixels (six pixels). The sixth and seventh pixels are pixels that can be seen by both eyes of the observer P. For this reason, the sixth and seventh pixels are displayed in black.

[0064] FIG. 19 is an explanatory diagram for explaining the operation of the display control unit 103 in Example 2-3. Based on the positions of the right eye ER and the left eye EL of the viewer P acquired by the position acquisition unit 105, the display control unit 103 separately determines a right-eye evaluation pixel range "pixels 6 to 11" with an evaluation pixel count of "q + p = 6" to be assigned to the position of the right eye ER, and a left-eye evaluation pixel range "pixels 2 to 7" with an evaluation pixel count of "q + p = 6" to be assigned to the position of the left eye EL. Next, the display control unit 103 determines an evaluation overlap range "pixels 6 to 7" where the right-eye evaluation pixel range "pixels 6 to 11" and the left-eye evaluation pixel range "pixels 2 to 7" overlap. As a result, the display control unit 103 displays the evaluation overlap range "pixels 6 to 7" in black. Here, since the number of pixels "2" in the evaluation overlap range is equal to or less than the first threshold value "2p=4", and the luminance is reduced for at least one pixel (the barrier edge surface luminance-reduced pixels "6th to 7th pixels") out of the "p=2" pixels "6th to 7th pixels" in the barrier edge overlap pixel range, the display control unit 103 further performs moiré prevention processing by similarly displaying in black the pixels "2nd to 3rd and 10th to 11th pixels" that are one-eye pixel number "q=4" away from the barrier edge surface luminance-reduced pixels "6th to 7th pixels".

[0065] This completes the description of the example of the control method for the stereoscopic display device 100 according to this embodiment.

[0066] According to this embodiment, the positions of the observer's right eye and the observer's left eye are acquired, a right-eye image display pixel range of the right-eye image to be assigned to the right-eye position and a left-eye image display pixel range of the left-eye image to be assigned to the left-eye position are determined, and the display is controlled to display the right-eye image in the right-eye image display pixel range and the left-eye image in the left-eye image display pixel range. This allows the right-eye image and the left-eye image to be assigned to appropriate pixels, even if the observer moves arbitrarily, thereby providing the observer with appropriate stereoscopic vision. Furthermore, a left-right overlap range that can be viewed by both the observer's right eye and left eye in the right-eye image display pixel range and the left-eye image display pixel range is determined, and if a left-right overlap range is determined, the display is controlled to reduce the luminance of one or more pixels included in the left-right overlap range. This reduces the impact of crosstalk due to the left-right overlap range, even if the right-eye image display pixel range and the left-eye image display pixel range are determined separately according to the observer's right eye and left eye positions, respectively, resulting in a change in the left-right overlap range that can be viewed by both eyes. This makes it possible to provide the viewer with an appropriate stereoscopic view.

[0067] Furthermore, the left-right overlap range changes depending on the actual interocular distance of the observer and the observation state of the observer (such as the posture of observer P, such as the tilt of the head or upper body), but according to this embodiment, by following the changes in the left-right overlap range, it is possible to reduce the effects of crosstalk caused by the left-right overlap range.

[0068] As described above, according to this embodiment, it is possible to obtain an effect that the stereoscopic vision of a viewer who may be moving can be improved.

[0069] On the other hand, a conventional three-dimensional display device (see Patent Document 1) can provide stereoscopic vision only under the conditions that the interocular distance of the observer is equal to the average interocular distance of a human and both of the observer's eyes are parallel to the display surface of the display. In the conventional three-dimensional display device, first, it is assumed that the interocular distance of the observer is equal to the average interocular distance of a human. Therefore, when determining the range visible to the left eye and the range visible to the right eye on the display surface, if the interocular distance is not equal to the average interocular distance, the range visible to the left eye and the range visible to the right eye cannot be correctly determined. Second, even if the interocular distance of the observer is equal to the average interocular distance of a human, if both of the eyes are not parallel to the display surface, the conventional three-dimensional display device does not use the positions of the left eye and the right eye independently to determine the range visible to the left eye and the range visible to the right eye, and therefore cannot correctly determine the range visible to the left eye and the range visible to the right eye. In a conventional 3D display device, even if the positions of the right eye and the left eye are acquired individually, the process of determining the visible range is performed assuming that the position of one eye is horizontally separated from the position of the other eye by a predetermined interocular distance. For example, in a conventional 3D display device, once the position of the left eye is acquired, the process of determining that the position of the right eye is located at a position shifted horizontally from the left eye position by a predetermined interocular distance is permitted. In other words, in a conventional 3D display device, the positions of the left eye and the right eye are not used independently to determine the range visible to the left eye and the range visible to the right eye. On the other hand, in the stereoscopic display device 100 according to the present embodiment, as described in the process of step S202, the three-dimensional coordinates of the positions of the right eye ER and the left eye EL of the viewer P acquired by the position acquisition unit 105 are independently used to determine the right-eye evaluation pixel range and the left-eye evaluation pixel range. Therefore, even if the interocular distance of the observer is not equal to the average interocular distance of a human being, or even if the observer's eyes are not parallel to the display surface of the display, the effects of crosstalk caused by the left-right overlapping range can be reduced by following the changes in the left-right overlapping range.

[0070] (Modification) Modifications of the embodiments of the present invention will be described in detail below with reference to the drawings. In the above-described embodiment, the optical element 102 is a parallax barrier, but the present invention is not limited to this. The optical element 102 may be, for example, a lenticular lens. In this modification, an example in which the optical element 102 is a lenticular lens will be described. The stereoscopic display device according to this modification will be referred to as a stereoscopic display device 100a. Note that the same components as those in the above-described embodiment will be assigned the same reference numerals, and descriptions of the same components and operations may be omitted.

[0071] 22 is a diagram showing an example of a stereoscopic display device 100a according to this modification. As shown in FIG. 1, the stereoscopic display device 100a includes a display 101, a lenticular lens 91, a display control unit 103, a storage unit 104, and a position acquisition unit 105.

[0072] The lenticular lens 91 is an example of an optical element. The lenticular lens 91 is made up of a plurality of cylindrical lenses 92. The lenticular lens 91 is configured by arranging a plurality of cylindrical lenses 92 extending in a second direction in a first direction. Like a parallax barrier, the lenticular lens 91 propagates a portion of image light, which is light emitted from subpixels assigned with a left-eye image ML, so that the light reaches the position of the left eye EL of the observer P. The lenticular lens 91 propagates a portion of image light, which is light emitted from subpixels assigned with a right-eye image MR, so that the light reaches the position of the right eye ER of the observer P. Therefore, the lenticular lens 91 (optical element) limits the left eye position, which is the position of the left eye EL at which the left-eye image ML can be viewed, and the right eye position, which is the position of the right eye ER at which the right-eye image MR can be viewed, by changing the direction in which light from the display surface of the display 101 propagates using the plurality of cylindrical lenses 92.

[0073] Example 3-1 in FIG. 23 is an example of pixels viewed by the viewer P due to limitations imposed by the lenticular lens 91. Because the lenticular lens has a light-condensing effect, only a portion of the multiple pixels constituting the one-eye image (left-eye image ML or right-eye image MR) is often observed. FIG. 23 illustrates a case in which the state of pixels observed through the lenticular lens is the same as the state of pixels observed through a parallax barrier with an aperture ratio equivalent to 25%. In the example of FIG. 23 , n = 16, m = 8, q = 4, p = 2, p + q = 6 (even number), number of central pixels = 2, first threshold = 2p = 4, and second threshold = 2p = 4. These values ​​may be determined during the design of the stereoscopic display device 100, or may be determined by evaluating a manufactured stereoscopic display device 100. When these values ​​are determined by evaluating a manufactured stereoscopic display device 100, for example, the number of pixels per eye, q, is determined by illuminating each pixel of the observed display 101.

[0074] FIG. 24 is an explanatory diagram for explaining the operation of the display control unit 103 in Example 3-1. Based on the positions of the right eye ER and the left eye EL of the viewer P acquired by the position acquisition unit 105, the display control unit 103 separately determines a right-eye evaluation pixel range "pixels 7-12" with an evaluation pixel count of "q+p=6" to be assigned to the position of the right eye ER, and a left-eye evaluation pixel range "pixels 15, 0-4" with an evaluation pixel count of "q+p=6" to be assigned to the position of the left eye EL. Next, the display control unit 103 determines that there is no evaluation overlap range, in which the right-eye evaluation pixel range "pixels 7-12" and the left-eye evaluation pixel range "pixels 15, 0-4" overlap. As a result, the display control unit 103 does not display black because there is no evaluation overlap range.

[0075] Example 3-2 in FIGS. 25 and 26 illustrates a case in which the actual interocular distance E' of the observer P is shorter than the average interocular distance E of a person during operation of the stereoscopic display device 100a. As a result, as shown in FIG. 26 , the distance between the two central pixels on the right eye side and the two central pixels on the left eye side is three pixels shorter than in Example 3-1 in FIG. 24 described above. FIG. 25 is an explanatory diagram for explaining how pixels on the display surface of the display 101 appear to the observer P in Example 3-2. On the right eye side in FIG. 25 , the pixels that can be viewed by the right eye ER of the observer P due to the limitations imposed by the lenticular lens 91 as an optical element are the sixth to eleventh pixels (six pixels). On the left eye side in FIG. 25 , the pixels that can be viewed by the left eye EL of the observer P due to the limitations imposed by the lenticular lens 91 as an optical element are the first to sixth pixels (six pixels). The sixth pixel is a pixel that can be viewed by both eyes of the observer P. Therefore, the sixth pixel is displayed with reduced brightness (black display).

[0076] FIG. 26 is an explanatory diagram for explaining the operation of the display control unit 103 in Example 3-2. Based on the positions of the right eye ER and the left eye EL of the viewer P acquired by the position acquisition unit 105, the display control unit 103 separately determines a right-eye evaluation pixel range "pixels 6-11" with an evaluation pixel count of "q+p=6" to be assigned to the position of the right eye ER, and a left-eye evaluation pixel range "pixels 1-6" with an evaluation pixel count of "q+p=6" to be assigned to the position of the left eye EL. Next, the display control unit 103 determines an evaluation overlap range "pixel 6" where the right-eye evaluation pixel range "pixels 6-11" and the left-eye evaluation pixel range "pixels 1-6" overlap. As a result, the display control unit 103 displays the evaluation overlap range "pixel 6" with reduced brightness (displayed black). Here, since the number of pixels "1" in the evaluation overlap range is equal to or less than the first threshold value "2p = 4", and the luminance is reduced for at least one pixel (barrier edge surface luminance-reduced pixel "sixth pixel") out of the "p = 2" pixels "sixth to seventh pixels" in the barrier edge overlap pixel range, the display control unit 103 further performs moiré prevention processing by similarly reducing the luminance (displaying black) for the "second and tenth pixels" that are one-eye pixel number "q = 4" away from the barrier edge surface luminance-reduced pixel "sixth pixel".

[0077] The configuration of the display is not limited to the configurations shown in the above-described embodiments and modifications. For example, in the above-described embodiments and modifications, an example has been described in which pixels on the display surface of the display are composed of red subpixels, green subpixels, and blue subpixels, and the pixels are arranged in a grid pattern in the first and second directions. However, the present invention is not limited to this. On the display surface, the pixels may be arranged based on a so-called delta arrangement, in which the pixels are arranged with a half-pitch offset between rows. Alternatively, on the display surface, the pixels may be arranged based on an arrangement called a honeycomb structure. Furthermore, the red subpixels, green subpixels, and blue subpixels may be arranged in stripes oblique to the second direction, rather than in stripes along the second direction.

[0078] Alternatively, the display may have square pixels arranged on the display surface, such as a rear projection display using a one-chip DLP (Digital Light Processing) (registered trademark), and may display red, green, and blue subpixels in a time-division manner. Alternatively, the display may have one pixel configured by three LED elements of RGB colors, such as an LED (light-emitting diode) display.

[0079] Furthermore, in the above-described embodiment and modified examples, an example in which the display is a self-luminous type has been described, but the present invention is not limited to this. A transmissive liquid crystal display and a backlight may be used instead of the self-luminous display 101. When a transmissive liquid crystal display and a backlight are used as the display, the optical element may be disposed in front of the display surface of the liquid crystal display (i.e., on the viewer's side), as in the above-described embodiment and modified examples, or may be disposed between the liquid crystal display and the backlight.

[0080] In the image display devices according to the above-described embodiments and modifications, the first eye is the right eye ER of the observer P, the second eye is the left eye EL of the observer P, the first image is the right-eye image MR, and the second image is the left-eye image ML. The right eye ER observes pixels assigned to the right-eye image MR through the optical element 102, and the left eye EL observes pixels assigned to the left-eye image ML through the optical element 102, thereby allowing the observer P to perceive a stereoscopic image. In other words, in the above-described embodiments and modifications, an example has been described in which the image display device is a stereoscopic display device used for stereoscopic viewing, but this is not limited to this. The configuration of the stereoscopic display device according to each embodiment may be used for applications other than stereoscopic viewing. As an example of another application, the stereoscopic display device may be used to allow multiple observers to view different images when the multiple observers view the display from different positions. In this case, in the image display device, the first eye is the eye of a first observer, the second eye is the eye of a second observer located at a different position from the first observer, the first image is a first observer image that is an image to be observed by the first observer, and the second image is a second observer image that is an image to be observed by the second observer, and the first eye of the first observer observes the pixels assigned to the first observer image through an optical element, and the second eye of the second observer observes the pixels assigned to the second observer image through an optical element, so that the first observer and the second observer each perceive different images.

[0081] The above is a description of an example of a control method for the image display device (stereoscopic display device 100, 100a) according to this embodiment and its modified examples. The image display device (stereoscopic display device 100, 100a) according to this embodiment and its modified examples includes a display 101, an optical element 102, a position acquisition unit 105, and a display control unit 103. The display 101 has a display surface including a plurality of pixels, and displays a first image (in this embodiment, a right-eye image MR) to be viewed by a first eye (in this embodiment, the right eye ER) and a second image (in this embodiment, a left-eye image ML) to be viewed by a second eye (in this embodiment, the left eye EL) on the display surface. The optical element 102 limits a first eye position (in this embodiment, the position of the right eye ER) that is a position at which the first eye (in this embodiment, the right eye ER) can view the first image (in this embodiment, the right-eye image MR) and a second eye position (in this embodiment, the position of the left eye EL) that is a position at which the second eye (in this embodiment, the left eye EL) can view the second image (in this embodiment, the left-eye image ML). The position acquisition unit 105 acquires a first eye position (in this embodiment, the position of the right eye ER) and a second eye position (in this embodiment, the position of the left eye EL). The display control unit 103 uses the first eye position (in this embodiment, the position of the right eye ER) and the second eye position (in this embodiment, the position of the left eye EL) independently to determine a first image display pixel range (in this embodiment, the right eye image display pixel range) in which to display the first image (in this embodiment, the right eye image MR) based on the first eye position (in this embodiment, the position of the right eye ER), and determines a second image display pixel range (in this embodiment, the left eye image display pixel range) in which to display the second image (in this embodiment, the left eye image ML) based on the second eye position (in this embodiment, the position of the left eye EL), and controls the display 101 so that the first image (in this embodiment, the right eye image MR) is assigned to the pixels included in the first image display pixel range (in this embodiment, the right eye image display pixel range), and the second image (in this embodiment, the left eye image ML) is assigned to the pixels included in the second image display pixel range (in this embodiment, the left eye image display pixel range).The display control unit 103 determines a binocular overlap range (in this embodiment, a left-right overlap range) that can be seen by both the first eye (in this embodiment, the right eye ER) and the second eye (in this embodiment, the left eye EL) in the first image display pixel range (in this embodiment, the right eye image display pixel range) and the second image display pixel range (in this embodiment, the left eye image display pixel range), and if it determines that a binocular overlap range (in this embodiment, a left-right overlap range) exists, controls the display 101 to reduce the brightness of one or more pixels included in the binocular overlap range (in this embodiment, the left-right overlap range).

[0082] With this configuration, the image display device (stereoscopic display device 100, 100a) according to this embodiment and the modified example can acquire the position of the observer's eyes and assign the first image and the second image to appropriate pixels, thereby improving the visibility of the image even if the observer's eyes are not positioned at predetermined positions. When the image display device is used for stereoscopic viewing, the observer's eyes may move arbitrarily, or the interocular distance of the observer may not be equal to the average interocular distance of a human. When the image display device is used as a multi-viewpoint display, the observer's eyes may move arbitrarily.

[0083] Although the embodiments of the present invention have been described above with reference to the drawings, the stereoscopic display device is not limited to the above-described embodiments, and various modifications, substitutions, combinations, and / or design changes can be made without departing from the spirit and scope of the present invention.

[0084] Furthermore, the effects of the above-described embodiments of the present invention are described as examples. Therefore, the embodiments of the present invention may also achieve other effects that a person skilled in the art can recognize from the description of the above-described embodiments in addition to the above-described effects.

[0085] 100...stereoscopic display device, 101...display, 102...optical element, 103...display control unit, 104...storage unit, 105...position acquisition unit, 3...detection device

Claims

1. a display having a display surface including a plurality of pixels, the display surface displaying a first image to be viewed by a first eye and a second image to be viewed by a second eye; an optical element that limits a first eye position, which is the first eye position at which the first image can be viewed, and a second eye position, which is the second eye position at which the second image can be viewed; a position acquisition unit that acquires the first eye position and the second eye position; a display control unit that uses the first eye position and the second eye position independently to determine a first image display pixel range in which the first image is to be displayed based on the first eye position, and determines a second image display pixel range in which the second image is to be displayed based on the second eye position, and controls the display so that the first image is assigned to pixels included in the first image display pixel range and the second image is assigned to pixels included in the second image display pixel range; Equipped with the display control unit determines an eye overlap range that can be seen by both the first eye and the second eye in the first image display pixel range and the second image display pixel range, and when it is determined that the eye overlap range exists, controls the display to reduce luminance of one or more pixels included in the eye overlap range; the display surface includes a plurality of pixels arranged along a first direction and a second direction intersecting the first direction; the display displays a set of the first image and the second image, each having a size of m pixels, on the display surface for every n pixels (n is a positive integer equal to or greater than 2m, and m is a positive integer); In order to determine the both-eye overlap range, the display control unit determines a first eye evaluation pixel range of a predetermined number of evaluation pixels to be assigned to the first eye position and a second eye evaluation pixel range of the predetermined number of evaluation pixels to be assigned to the second eye position, determines an evaluation overlap range in which the determined first eye evaluation pixel range and the second eye evaluation pixel range overlap, as the both-eye overlap range, and controls the display to reduce luminance in the evaluation overlap range when it is determined that the evaluation overlap range exists. the optical element is a parallax barrier having a light-blocking region and a light-transmitting region, the number of evaluation pixels is equal to or greater than the number obtained by multiplying the number of n pixels by the aperture ratio of the parallax barrier and is equal to or less than the number obtained by multiplying the number of n pixels by the aperture ratio of the parallax barrier plus the number of pixels included in the eye overlap area, Video display device.

2. a display having a display surface including a plurality of pixels, the display surface displaying a first image to be viewed by a first eye and a second image to be viewed by a second eye; an optical element that limits a first eye position, which is the first eye position at which the first image can be viewed, and a second eye position, which is the second eye position at which the second image can be viewed; a position acquisition unit that acquires the first eye position and the second eye position; a display control unit that uses the first eye position and the second eye position independently to determine a first image display pixel range in which the first image is to be displayed based on the first eye position, and determines a second image display pixel range in which the second image is to be displayed based on the second eye position, and controls the display so that the first image is assigned to pixels included in the first image display pixel range and the second image is assigned to pixels included in the second image display pixel range; Equipped with the display control unit determines an eye overlap range that can be seen by both the first eye and the second eye in the first image display pixel range and the second image display pixel range, and when it is determined that the eye overlap range exists, controls the display to reduce luminance of one or more pixels included in the eye overlap range; In order to determine the both-eye overlap range, the display control unit determines a first eye evaluation pixel range of a predetermined number of evaluation pixels to be assigned to the first eye position and a second eye evaluation pixel range of the predetermined number of evaluation pixels to be assigned to the second eye position, determines an evaluation overlap range in which the determined first eye evaluation pixel range and the second eye evaluation pixel range overlap, as the both-eye overlap range, and controls the display to reduce luminance in the evaluation overlap range when it is determined that the evaluation overlap range exists. the display surface includes a plurality of pixels arranged along a first direction and a second direction intersecting the first direction; the display displays a set of the first image and the second image, each having a size of m pixels, on the display surface for every n pixels (n is a positive integer equal to or greater than 2m, and m is a positive integer); the optical element is a lenticular lens made up of a plurality of cylindrical lenses, the number of evaluation pixels is equal to or greater than the number of pixels included in the eye overlap area; Video display device.

3. the display control unit determines, as the both-eye overlap range, a range that is an end of a range observed from the first eye position through the optical element and that is also an end of a range observed from the second eye position through the optical element.

3. The image display device according to claim 1 or 2.

4. a viewpoint detection unit that detects the first eye position and the second eye position individually; the position acquisition unit acquires the first eye position and the second eye position individually detected by the viewpoint detection unit; 3. The image display device according to claim 1 or 2.

5. the display control unit determines whether or not the eye overlap range exists, and when it determines that the eye overlap range does not exist, determines an area that is viewable from the first eye position and not viewable from the second eye position as the first image display pixel range, determines an area that is viewable from the second eye position and not viewable from the first eye position as the second image display pixel range, and controls the display so that the first image is assigned to pixels included in the first image display pixel range, and the second image is assigned to pixels included in the second image display pixel range.

3. The image display device according to claim 1 or 2.

6. the one-eye pixel range is determined based on an average interocular distance of a person and a ratio of pixels visible by the optical element among n pixels; 3. The image display device according to claim 1 or 2.

7. When the number of pixels in the evaluation overlap range is equal to or less than a predetermined first threshold, when the display control unit reduces the luminance of at least one pixel among the pixels in the both-eye overlap range that may have their luminance reduced, the display control unit further reduces the luminance of pixels that are separated from the at least one pixel by the number of pixels in the one-eye pixel range as a moiré prevention process.

7. The image display device according to claim 6.

8. When the number of pixels in the evaluation overlap range exceeds a predetermined second threshold, the display control unit only reduces the luminance of the pixels in the evaluation overlap range that exceed the second threshold, and does not perform moiré prevention processing.

7. The image display device according to claim 6.

9. the display control unit determines whether or not there is partial non-uniformity in the luminance reduction process across the entire display surface of the display, and if there is partial non-uniformity in the luminance reduction process as a result of the determination, executes a predetermined luminance uniformization process.

3. The image display device according to claim 1 or 2.

10. the display control unit reduces the luminance of pixels present in an area of ​​the display surface that is brighter than other areas by a certain amount or more, in order to uniformly adjust the brightness of the display surface; 10. The image display device according to claim 9.

11. the display control unit performs control to increase the luminance of the entire display surface when the ratio of the pixels whose luminance is to be reduced on the display surface is equal to or greater than a certain value.

3. The image display device according to claim 1 or 2.

12. the optical element is a parallax barrier having a light-blocking region and a light-transmitting region, the optical element limits the first eye position and the second eye position by the light blocking region and the light transmitting region; 3. The image display device according to claim 1 or 2.

13. the optical element is a lenticular lens made up of a plurality of cylindrical lenses, the optical element limits the first eye position and the second eye position by changing a direction in which light from the display surface propagates using the plurality of cylindrical lenses; 3. The image display device according to claim 1 or 2.

14. the first eye is the right eye of the observer, and the second eye is the left eye of the observer; the first image is a right-eye image and the second image is a left-eye image; the right eye observes the pixels to which the right-eye image is assigned through the optical element, and the left eye observes the pixels to which the left-eye image is assigned through the optical element, thereby allowing the viewer to perceive a stereoscopic image.

3. The image display device according to claim 1 or 2.