Patent Publication Number: US-8994759-B2

Title: Display

Description:
BACKGROUND 
     The present technology relates to a display performing stereoscopic display by a naked-eye system with use of a parallax separation structure such as a parallax barrier. 
     Techniques of performing stereoscopic display include a glass system with use of glasses for stereoscopic vision and a naked-eye system capable of achieving stereoscopic vision by naked eyes without glasses for stereoscopic vision. A typical glass system is a shatter glass system using shutter glasses with a left-eye shutter and a right-eye shutter. In the shutter glass system, a left-eye parallax image and a right-eye parallax image are alternately displayed on a two-dimensional display panel at high speed in a frame-sequential manner. Then, the left-eye shutter and the right-eye shutter are alternately opened and closed in synchronization with switching of the parallax images to allow only the left-eye parallax image and the right-eye parallax image to enter a left eye and a right eye of a viewer, respectively, thereby achieving stereoscopic vision. 
     On the other hand, typical naked-eye systems include a parallax barrier system and a lenticular lens system. In the parallax barrier system and the lenticular lens system, parallax images for stereoscopic vision (a right-eye parallax image and a left-eye parallax image in the case of two perspectives) which are spatially separated from one another are displayed on a two-dimensional display panel, and the parallax images are separated by parallax in a horizontal direction by a parallax separation structure to achieve stereoscopic vision. In the parallax barrier system, as the parallax separation structure, a parallax barrier having slit-like openings is used. In the lenticular system, as the parallax separation structure, a lenticular lens including a plurality of cylindrical split lenses arranged in parallel is used. 
     SUMMARY 
     In a naked-eye system using a parallax separation structure, there is an issue that when a view position of a viewer is out of a predetermined design region, proper stereoscopic vision is not achievable. Moreover, Japanese Unexamined Patent Application Publication No. H9-50019 discloses a display capable of reducing a preferred viewing distance in design; however, too short preferred viewing distance may cause a too narrow space between a parallax separation structure and a display section displaying an image, thereby causing difficulty in manufacturing. 
     It is desirable to provide a display capable of performing optimum stereoscopic display according to a view position. 
     According to an embodiment of the technology, there is provided a display including: a display section including a plurality of first pixels to a plurality of nth pixels, where n is an integer of 4 or more, and displaying a plurality of perspective images assigned to the first to nth pixels; a detection section detecting a view position of a viewer; and a display control section varying the number of the plurality of perspective images assigned to the first to nth pixels and varying a correspondence relationship between the first to nth pixels and the perspective images, according to the view position of the viewer. 
     In the display according to the embodiment of the technology, control is performed to vary the number of the plurality of perspective images assigned to the first to nth pixels and vary a correspondence relationship between the first to nth pixels and the perspective images, according to the view position of the viewer. 
     In the display according to the embodiment of the technology, the number of the plurality of perspective images assigned to the first to nth pixels and the correspondence relationship between the first to nth pixels and the perspective images are varied according to the view position of the viewer; therefore, optimum stereoscopic display according to the view position is allowed to be performed. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the technology as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the specification, serve to explain the principles of the technology. 
         FIG. 1  is a block diagram illustrating an example of a whole configuration of a display according to an embodiment of the technology. 
         FIG. 2  is a sectional view illustrating a configuration example in the case where stereoscopic display with four perspectives is performed in the display illustrated in  FIG. 1 . 
         FIG. 3  is a sectional view illustrating a reference example in the case where stereoscopic display with two perspectives is performed. 
         FIG. 4  is an explanatory diagram of a preferred viewing distance. 
         FIG. 5  is an explanatory diagram of viewable pixels in the case where a view position of a viewer is located in a first light-convergence region when stereoscopic display with four perspectives illustrated in  FIG. 2  is performed. 
         FIG. 6  is an explanatory diagram of viewable pixels in the case where the view position of the viewer is located in a predetermined distance range from the first light-convergence region when stereoscopic display with four perspectives illustrated in  FIG. 2  is performed. 
         FIG. 7  is an explanatory diagram of viewable pixels in the case where the view position of the viewer is located in a predetermined distance range from the first light-convergence region and a fourth light-convergence region when stereoscopic display with four perspectives illustrated in  FIG. 2  is performed. 
         FIG. 8  is a first explanatory diagram of viewable pixels in the case where the view position of the viewer is located at a distance Z 0 / 2  equal to a half of a preferred viewing distance (a second distance Z 0 ) with four perspectives when stereoscopic display with four perspectives illustrated in  FIG. 2  is performed. 
         FIG. 9  is a second explanatory diagram of viewable pixels in the case where the view position of the viewer is located at the distance Z 0 / 2  equal to a half of the preferred viewing distance (the second distance Z 0 ) with four perspectives when stereoscopic display with four perspectives illustrated in  FIG. 2  is performed. 
         FIG. 10  is an explanatory diagram, where a part (A) illustrates pixel numbers viewable by a right eye and a luminance distribution in a viewing state illustrated in  FIG. 9 , and a part (B) illustrates pixel numbers viewable by a left eye and a luminance distribution in the viewing state illustrated in  FIG. 9 . 
         FIG. 11  is an explanatory diagram, where a part (A) illustrates a correspondence relationship between a plurality of sub-regions configured to allow stereoscopic display with two perspectives at the distance Z 0 / 2  in a configuration where stereoscopic display with four perspectives is achievable at the distance Z 0  and pixel numbers to which a right-eye image is assigned in each of the sub-regions, and a part (B) illustrates a correspondence relationship between a plurality of sub-regions configured in a manner similar to the case of the part (A) and pixel numbers to which a left-eye image is assigned in each of the sub-regions. 
         FIG. 12  is an explanatory diagram illustrating a luminance distribution of each pixel in two adjacent sub-regions in the case where stereoscopic display illustrated in  FIG. 11  is performed. 
         FIG. 13  is an explanatory diagram of viewable pixels in the case where the view position of the viewer is located at a distance Z 0 / 2  equal to a half of a preferred viewing distance with five perspectives when stereoscopic display with five perspectives is performed. 
         FIG. 14  is an explanatory diagram, where a part (A) illustrates pixel numbers viewable by a right eye and a luminance distribution in a viewing state illustrated in  FIG. 13 , and a part (B) illustrates pixel numbers viewable by a left eye and a luminance distribution in the viewing state illustrated in  FIG. 13 . 
         FIG. 15  is an explanatory diagram, where a part (A) illustrates a correspondence relationship between a plurality of sub-regions configured to allow stereoscopic display with two perspectives at the distance Z 0 / 2  in a configuration where stereoscopic display with five perspectives is achievable at the distance Z 0  and pixel numbers to which a right-eye image is assigned in each of the sub-regions, and a part (B) illustrates a correspondence relationship between a plurality of sub-regions configured in a manner similar to the case of the part (A) and pixel numbers to which a left-eye image is assigned in each of the sub-regions. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A preferred embodiment of the present technology will be described in detail referring to the accompanying drawings. 
     [Whole Configuration of Display] 
       FIG. 1  illustrates a configuration example of a display according to an embodiment of the technology. The display includes a detection section  1 , a display control section  4 , an image production section  5 , and a display section  6 . The detection section  1  includes an image pickup section  2  and a view position evaluation section  3 . 
     The display section  6  is configured of a two-dimensional display such as a liquid crystal display panel, an electroluminescence display panel or a plasma display. A plurality of pixels are two-dimensionally arranged on a display screen of the display section  6 . Images are displayed on the display screen of the display section  6  according to a stereoscopic display system of the display. First to nth (where n is an integer of 4 or more) numbers corresponding to first to nth perspectives, respectively, in stereoscopic display are assigned to the plurality of pixels (or sub-pixels) of the display section  6 . 
     The display performs stereoscopic display by a naked-eye system, and the stereoscopic display system is a system using a parallax separation structure such as a parallax barrier system or a lenticular lens system. In the case of the lenticular lens system, as the parallax separation structure, for example, a lenticular lens including a plurality of cylindrical split lenses arranged in parallel is used. A parallax composite image created by combining parallax images (perspective images) corresponding to a plurality of perspectives in one screen is displayed on the display section  6 . In other words, a plurality of perspective images are spatially separated and displayed. As will be described later, the display varies the number of perspective images displayed on the display section  6  according to a view position of a viewer. For example, in the case where the view position of the viewer is located at a first distance Z 0 / 2  (refer to  FIG. 9  or the like which will be described later), a left-eye image and a right-eye image which are parallax images corresponding to two perspectives, i.e., left and right perspectives are displayed as the plurality of perspective images. Moreover, for example, in the case where the view position of the viewer is located at a second distance Z 0  which is a normal preferred viewing distance, parallax images corresponding to a plurality of perspectives, for example, first to fourth perspective images are displayed as the plurality of perspective images (refer to  FIG. 2  or the like which will be described later). 
     Hereinafter, in the embodiment, the case where stereoscopic display by the parallax barrier system is performed will be described. In the case of the parallax barrier system, for example, as illustrated in  FIG. 2 , as the parallax separation structure, a barrier element  7  is used. The barrier element  7  has opening sections  8  allowing light to pass therethrough and shielding sections  9  shielding light. The barrier element  7  may be a fixed parallax barrier or a variable parallax barrier. In the case of the fixed parallax barrier, for example, a parallax barrier formed by forming a pattern including the opening sections  8  and the shielding sections  9  with use of metal in a thin-film shape on a surface of a transparent plane parallel plate (base) is allowed to be used. In the case of the variable parallax barrier, for example, patterns of the opening sections  8  and the shielding sections  9  are allowed to be selectively formed with use of, for example, a display function (a light modulation function) by backlight system liquid crystal display elements. It is to be noted that  FIG. 2  illustrates an example in which the barrier element  7  is disposed on a display plane of the display section  6 ; however, the barrier element  7  may be disposed on a back plane of the display section  6 , and, for example, in the case where a backlight system liquid crystal display panel is used as the display section  6 , the barrier element  7  may be disposed on the back plane of the liquid crystal display panel between a backlight and the liquid crystal display panel. 
     The image pickup section  2  takes an image of a viewer. The view position evaluation section  3  evaluates the view position of the viewer (a position in an in-plane direction parallel to the viewing distance from the display section  6  and the display plane) by analyzing the image taken by the image pickup section  2 . The view position is allowed to be detected by the detection section  1  with use of, for example, a face tracking technique. It is to be noted that the viewing distance is typically the distance from a display plane of the display section  6  to a central position between both eyes of the viewer. 
     The display control section  4  controls an image displayed on the display section  6  according to the view position of the viewer detected by the detection section  1 . As will be described later, in the case where the view position of the viewer is located at the first distance Z 0 / 2  from the display section  6 , the display control section  4  performs display control on pixels in each of a plurality of sub-regions  31  (refer to  FIG. 11  or the like which will be described later) of the display section  6 , independently, thereby to vary the correspondence relationship between the first to nth pixels and the perspective images (a left-eye image and a right-eye image) for each of the sub-regions  31 . As will be described later, in the case where the view position of the viewer is located at the second distance Z 0 , the display control section  4  assigns the first to nth perspective images as a plurality of perspective images to the first to nth pixels in an entire screen. 
     The image production section  5  produces image data including a plurality of perspective images according to the view position of the viewer in response to control by the display control section  4  to supply the image data to the display section  6 . The display control section  4  allows the display section  6  to display the image data produced by the image production section  5 . 
     [Principle of Stereoscopic Display at Normal Preferred Viewing Distance (Second Distance Z 0 )] 
       FIG. 2  illustrates a principle in the case where stereoscopic display with four perspectives is performed in the display. A display principle in the example in  FIG. 2  is basically similar to a principle of stereoscopic display with four perspectives by a parallax barrier system in related art. First to fourth numbers corresponding to four perspectives are assigned to a plurality of pixels (or sub-pixels) of the display section  6 . The display control section  4  assigns first to fourth perspective images as a plurality of perspective images to the first to fourth pixels, respectively, in the entire screen of the display section  6 . Light beams from the first to fourth pixels of the display section  6  are separated by the opening sections  8  of the barrier element  7 . The separated light beams reach first to fourth light-convergence regions  11  to  14  located at the second distance Z 0 , respectively. In other words, for example, all light beams from the first pixels in the entire screen reach the first light-convergence region  11  located at the second distance Z 0  by a separation function of the barrier element  7 . Likewise, all light beams from the second to fourth pixels in the entire screen reach light-convergence regions to which corresponding numbers are assigned, respectively. 
     The width of each of the first to fourth light-convergence regions  11  to  14  is equal to a pupillary distance E (typically 65 mm). Therefore, a right eye  10 R and a left eye  10 L of the viewer are located in different light-convergence regions, and view different perspective images to achieve stereoscopic vision. For example, in the example in  FIG. 2 , the right eye  10 R of the viewer is located in the second light-convergence region  12 , and the left eye  10 L of the viewer is located in the third light-convergence region  13 . In this case, stereoscopic vision is achieved with an image (the second perspective image) created by light from the second pixels and an image (the third perspective image) created by light from the third pixels. In the case where the view position is moved in a horizontal direction, different perspective images corresponding to the moved position are viewed to achieve stereoscopic vision. 
       FIG. 3  illustrates a principle in the case where stereoscopic display with two perspectives is performed by a related-art system as a reference example in comparison with  FIG. 2 . The principle is basically the same as that in the case of stereoscopic display with four perspectives illustrated in  FIG. 2 , except for the number of perspectives is two. In the display section  6 , as a plurality of pixels, sub-pixels of RGB are alternately arranged, and first and second numbers are assigned to respective sub-pixels. A first perspective image (a right-eye image) and a second perspective image (a left-eye image) are assigned to the first sub-pixels and the second sub-pixels, respectively, in the entire screen of the display section  6 , and the first and second perspective images are displayed. Light beams from the first sub-pixels and the second sub-pixels in the display section  6  are separated by the opening sections  8  of the barrier element  7 . The separated light beams reach the first and second light-convergence regions  11  and  12  located at the second distance Z 0 , respectively. In other words, all light beams from the first pixels in the entire screen reach the first light-convergence region  11  located at the second distance Z 0  by the separation function of the barrier element  7 . Likewise, all light beams from the second pixels in the entire screen reach the second light-convergence region  12  located at the second distance Z 0 . The width of each of the first and second light-convergence regions  11  and  12  is equal to the pupillary distance E (typically 65 mm). Therefore, the right eye  10 R and the left eye  10 L of the viewer are located in different light-convergence regions, and view different perspective images to achieve stereoscopic vision. 
     [Normal Preferred Viewing Distance (Second Distance Z 0 ) in Design] 
     Referring to  FIG. 4 , a preferred viewing distance (the second distance Z 0 ) in design in the case where stereoscopic display based on the display principle illustrated in  FIGS. 2 and 3  is performed will be described below. In an example illustrated in  FIG. 4 , the display section  6  is, for example, a backlight system liquid crystal display panel, and a backlight  80  is disposed on the back plane of the display section  6 . The display section  6  includes a first transparent substrate  61  and a second transparent substrate  62  which face each other, and includes a pixel section  63  between the substrates  61  and  62 . The barrier element  7  is, for example, transmissive type variable parallax barrier element, and includes a first transparent substrate  71  and a second transparent substrate  72  which face each other, and has opening sections  8  and shielding sections  9  between the substrates  71  and  72 . In addition, the display section  6  and the barrier element  7  each include a polarizing plate or an adhesive layer on both surfaces or one surface thereof. 
     In  FIG. 4 , the pupillary distance is E, a pitch between pixels (or sub-pixels) in the display section  6  is P. A gap between the pixel section  63  of the display section  6  and the opening sections  8  and the shielding sections  9  of the barrier element  7  is G. Moreover, a refractive index of a substrate or the like disposed between the pixel section  63  and the opening sections  8  and the shielding sections  9  is n. A distance from a central portion of a surface of the barrier element  7  to a central position between the left eye  10 L and the right eye  10 R of the viewer is A. In this case, the following relational expression is established in design. In the case where stereoscopic display is performed based on the display principle illustrated in  FIGS. 2 and 3 , the normal preferred viewing distance (the second distance Z 0 ) in design has a value according to the following relational expression.
 
 A:E=G/n:P  
 
[Relationship Between View Position and Pixel to be Viewed]
 
       FIG. 5  illustrates viewable pixels in the case where the view position of the viewer is located in the first light-convergence region  11  when stereoscopic display with four perspectives illustrated in  FIG. 2  is performed. Moreover,  FIG. 6  illustrates viewable pixels in the case where the view position of the viewer is located in a predetermined distance range from the first light-convergence region  11 . It is to be noted that in  FIGS. 5 and 6 , the barrier element  7  is not illustrated. In  FIG. 7  and the following drawings, the barrier element  7  is not illustrated. 
     As illustrated in  FIG. 5 , in the case where the view position of the viewer is located in the first light-convergence region  11 , all light beams from the first pixels in the entire screen reach the right eye  10 R (or the left eye  10 L) of the viewer. Moreover, as illustrated in  FIG. 6 , in the case where the view position is located in a predetermined region  20  within a predetermined distance range from the first light-convergence region  11 , all light beams from the first pixels in the entire screen reach the right eye  10 R (or the left eye  10 L) of the viewer. 
       FIG. 7  illustrates viewable pixels in the case where the view position of the viewer is located out of the predetermined region  20  in  FIG. 6 , but in the predetermined distance range from the first light-convergence region  11  and the fourth light-convergence region  14 . In this case, light beams from the first pixels in a first display region  6 A of the display section  6  and light beams from the fourth pixels in a second display region  6 B reach the right eye  10 R (or the left eye  10 L) of the viewer. In other words, in this case, the right eye  10 R (or the left eye  10 L) of the viewer views not only light beams from the first pixels (the first perspective image) but also light beams from the fourth pixels (the fourth perspective image). 
     Viewable pixels (a perspective image) in the case where, as illustrated in  FIG. 7 , the view position of the viewer is located out of the predetermined region  20  is determined by analyzing which light-convergence regions light beams having reached an eye are supposed to reach. 
       FIGS. 8 and 9  illustrate viewable pixels in the case where the view position of the viewer is located at a distance (a first distance Z 0 / 2 ) equal to a half of the preferred viewing distance (the second distance Z 0 ) with four perspectives. The right eye  10 R is located in a first region  21  at the first distance Z 0 / 2 , and the left eye  10 L is located in a second region  22  at the first distance Z 0 / 2 . The width of the first region  21  and the width of the second region  22  are each equal to the pupillary distance E (typically 65 mm). 
     In the case where the view position is located at the first distance Z 0 / 2 , as illustrated in  FIG. 8 , pixels (perspective images) viewed by the right eye  10 R and the left eye  10 L of the viewer are different by two perspectives from those in the case where the view position is located on the preferred viewing distance (the second distance Z 0 ) in design. Moreover, as illustrated in  FIG. 9 , light beams from the first to fourth pixels (the first to fourth perspective images) reach each of the right eye  10 R and the left eye  10 L. 
     A part (A) in  FIG. 10  illustrates pixel numbers viewable by the right eye  10 R and a luminance distribution in a viewing state illustrated in  FIG. 9 . A part (B) in  FIG. 10  illustrates pixel numbers viewable by the left eye  10 L and a luminance distribution in the viewing state illustrated in  FIG. 9 . In the viewing state illustrated in  FIG. 9 , the right eye  10 R and the left eye  10 L view pixels (perspective images) different from one of four regions to another in the display section  6 . The width of each of the four regions is equal to the pupillary distance E (typically 65 mm). More specifically, as illustrated in the part (A) in  FIG. 10 , the right eye  10 R views the third pixel (the third perspective image), the second pixel (the second perspective image), the first pixel (the first perspective image), and the fourth pixel (the fourth perspective image) in order from an end of the display screen. Moreover, as illustrated in the part (B) in  FIG. 10 , the left eye  10 L views the first pixel (the first perspective image), the fourth pixel (the fourth perspective image), the third pixel (the third perspective image), and the second pixel (the second perspective image) in order from the end of the display screen. 
     [Optimized Stereoscopic Display Method in the Case Where View Position is Located at first distance Z 0 / 2 ] 
     Next, referring to  FIGS. 11 and 12 , an optimized stereoscopic display method in the case where the view position is located at the first distance Z 0 / 2  will be described below. It is obvious from the above description referring to  FIGS. 8 to 10  that in the case where the view position is located at the first distance Z 0 / 2 , proper stereoscopic vision is not achieved while four perspective images, i.e., the first to fourth perspective images are displayed on the display section  6 . Therefore, in the embodiment, in the case where the view position is located at the first distance Z 0 / 2 , the display control section  4  controls the display section  6  to display two perspective images, i.e., a right-eye image and a left-eye image instead of the first to fourth perspective images. 
     A part (A) in  FIG. 11  illustrates a correspondence relationship between a plurality of sub-regions  31  configured to allow stereoscopic display with two perspectives at the first distance Z 0 / 2  in a configuration where stereoscopic display with four perspectives is achievable at the second distance Z 0  (refer to  FIG. 2 ) and pixel numbers to which the right-eye image is assigned in each of the sub-regions  31 . A part (B) in  FIG. 11  illustrates a correspondence relationship between a plurality of sub-regions  31  configured in a manner similar to the case of the part (A) in  FIG. 11  and pixel numbers to which the left-eye image is assigned in each of the sub-regions  31 . 
     In the case where the view position of the viewer is located at the first distance Z 0 / 2 , the display control section  4  performs display control on the first to fourth pixels in each of the sub-regions  31  (refer to  FIG. 11 ) of the display section  6 , independently, and performs control to vary the correspondence relationship between the first to fourth pixels and the perspective images (the right-eye image and the left-eye image) for each of the sub-regions  31 . In this case, the display control section  4  assigns the right-eye image and the left-eye image to the first to fourth pixels in each of the sub-regions  31 , and in the case where the view position of the viewer is located at the first distance Z 0 / 2 , the display control section  4  assigns the right-eye image to pixels which correspond to first to fourth light-convergence regions  11  to  14  and are viewable from the position of the right eye  10 R, and assigns the left-eye image to pixels which correspond to the first to fourth light-convergence regions  11  to  14  and are viewable from the position of the left eye  10 L. In the display section  6 , each sub-region includes first pixels to fourth pixels. The display control section  4  assigns the right-eye image to two adjacent pixels of the first pixel to the fourth pixel and assigns the left-eye image to other two adjacent pixels of the first pixel to the fourth pixels, in each sub-region. Moreover, a combination of the two adjacent pixels to which the right-eye image is assigned and a combination of the other two adjacent pixels to which the left-eye image is assigned vary from one sub-region to another. 
     More specifically, as illustrated in  FIG. 11 , for example, in a first sub-region  31 - 1 , the display control section  4  assigns the right-eye image to the first and second pixels, and assigns the left-eye image to the third and fourth pixels. Moreover, in a second sub-region  31 - 2  adjacent to the first sub-region  31 - 1 , the display control section  4  assigns the right-eye image to the second and third pixels, and assigns the left-eye image to the first and fourth pixels. 
     Moreover, the display control section  4  performs control to move positions in a horizontal direction of respective sub-regions (borders  30  between a plurality of sub-regions  31 ) in response to movement in a horizontal direction of the view position of the viewer. 
       FIG. 12  schematically illustrates a luminance distribution of each pixel in two adjacent sub-regions  31 - 1  and  31 - 2  in the case where stereoscopic display as illustrated in the parts (A) and (B) in  FIG. 11  is performed. In the case where the view position of the viewer is located at the first distance Z 0 / 2 , the display control section  4  performs display control to allow luminance of the first pixel and the third pixel to be relatively lowest with respect to that of the second pixel when a boundary portion between the first sub-region  31 - 1  and the second sub-region  31 - 2  is viewed from the position of the right eye  10 R and to allow luminance of the first pixel and the third pixel to be relatively lowest with respect to that of the fourth pixel when the boundary portion is viewed from the position of the left eye  10 L. 
     [Modifications] 
     In the above description, the case of stereoscopic display with four perspectives is described as an example; however, the display according to the embodiment is applicable to the case where stereoscopic display with five or more perspectives is performed.  FIGS. 13 to 15  illustrate an example in the case where stereoscopic display with five perspectives is performed. In this case, first to fifth numbers are assigned to a plurality of pixels (or sub-pixels) of the display section  6 . In the case where the view position of the viewer is located at a preferred viewing distance (the second distance Z 0 ) with five perspectives, the display control section  4  assigns first to fifth perspective images as a plurality of perspective images to first to fifth pixels in the entire screen of the display section  6 , and displays the perspective images. 
       FIG. 13  illustrates viewable pixels in the case where the view position of the viewer is located at a distance (the first distance Z 0 / 2 ) equal to a half of the preferred viewing distance (the second distance Z 0 ) with five perspectives when stereoscopic display with five perspectives is performed. The right eye  10 R is located in the first region  21  at the first distance Z 0 / 2 , and the left eye  10 L is located in the second region  22  at the first distance Z 0 / 2 . The width of each of the first region  21  and the second region  22  is equal to the pupillary distance E (typically 65 mm). 
     In the case where the view position is located at the first distance Z 0 / 2 , as illustrated in  FIG. 13 , light beams from the first to fifth pixels (first to fifth perspective images) reach the right eye  10 R and the left eye  10 L. 
     A part (A) in  FIG. 14  illustrates pixel numbers viewable by the right eye  10 R and a luminance distribution in a viewing state illustrated in  FIG. 13 . A part (B) in  FIG. 14  illustrates pixel numbers viewable by the left eye  10 L and a luminance distribution in the viewing state illustrated in  FIG. 13 . In the viewing state illustrated in  FIG. 13 , the right eye  10 R and the left eye  10 L view pixels (perspective images) different from one of the four regions to another in the display section  6 . The width of each of the four regions is equal to the pupillary distance E (typically 65 mm). More specifically, as illustrated in the part (A) in  FIG. 14 , the right eye  10 R views the third pixel (the third perspective image), the second pixel (the second perspective image), the first pixel (the first perspective image), and the fifth pixel (the fifth perspective image) in order from an end of the display screen. Moreover, as illustrated in the part (B) in  FIG. 14 , the left eye  10 L views the fifth pixel (the fifth perspective image), the fourth pixel (the fourth perspective image), the third pixel (the third perspective image), and the second pixel (the second perspective image) in order from the end of the display screen. 
     It is obvious form the above description referring to  FIGS. 13 and 14  that in the case where the view position is located at the first distance Z 0 / 2 , proper stereoscopic vision is not achieved while five perspective images, i.e., the first to fifth perspective images are displayed on the display section  6 . Therefore, in the case where the view position is located at the first distance Z 0 / 2 , the display control section  4  controls the display section  6  to display two perspective images, i.e., the right-eye image and the left-eye image instead of the first to fifth perspective images. 
     A part (A) in  FIG. 15  illustrates a correspondence relationship between a plurality of sub-regions  31  configured to allow stereoscopic display with two perspectives at the first distance Z 0 / 2  in a configuration where stereoscopic display with five perspectives is achievable at the second distance Z 0  and pixel numbers to which the right-eye image is assigned in each of the sub-regions  31 . A part (B) in  FIG. 15  illustrates a correspondence relationship between a plurality of sub-regions  31  configured in a manner similar to the case of the part (A) in  FIG. 15  and pixel numbers to which the left-eye image is assigned in each of the sub-regions  31 . 
     In the case where the view position of the viewer is located at the first distance Z 0 / 2 , the display control section  4  performs display control on the first to fifth pixels in each of the sub-regions  31  of the display section  6 , independently, and performs control to vary the correspondence relationship between the first to fifth pixels and the perspective images (the right-eye image and the left-eye image) for each of the sub-regions  31 . In this case, the display control section  4  assigns the right-eye image and the left-eye image to the first to fifth pixels in each of the sub-regions  31 , and in the case where the view position of the viewer is located at the first distance Z 0 / 2 , the display control section  4  assigns the right-eye image to pixels viewable from the position of the right eye  10 R and corresponding to first to fifth light-convergence regions  11  to  15 , and assigns the left-eye image to pixels viewable from the position of the left eye  10 L and corresponding to the first to fifth light-convergence regions  11  to  15 . In the display section  6 , each sub-region includes first pixels to fifth pixels. The display control section  4  assigns the right-eye image to two adjacent pixels of the first pixel to the fifth pixel and assigns the left-eye image to other two adjacent pixels of the first pixel to the fifth pixel, in each sub-region. Moreover, a combination of the two adjacent pixels to which the right-eye image is assigned and a combination of the other two adjacent pixels to which the left-eye image is assigned vary from one sub-region to another. A specific method of assigning the images to the pixels is similar to that in the case of the above-described stereoscopic display with four perspectives. 
     [Effects] 
     As described above, in the display according to the embodiment, the number of perspective images assigned to the first to nth pixels and a correspondence relationship between the first to nth pixels and perspective images are varied according to the view position of the viewer; therefore, optimum stereoscopic display according to the view position is allowed to be performed. In the display, display is allowed to be optimized only by image processing, and it is not necessary to make movement or the like of the barrier element  7 , and display is allowed to be easily executed. Moreover, in the case where the view position of the viewer is moved in a horizontal direction while the view position of the viewer is located at the first distance Z 0 / 2 , it is only necessary to perform control to move the boundaries  30  between a plurality of sub-regions  31 , and the control is easily executed. Moreover, optimum display in consideration of the luminance distribution as illustrated in  FIG. 12  is performed; therefore, display with less crosstalk is allowed to be performed. Further, it is difficult to recognize image switching from one of a plurality of sub-regions  31  to another; therefore, natural display for the viewer is allowed to be performed. 
     Moreover, in related art, when a space between the parallax separation structure and the display section is too small, it is necessary to perform glass grinding or the like to reduce the thickness of a glass substrate or the like between the parallax separation structure and the display section, thereby causing difficulty in manufacturing. In the display according to the embodiment, the preferred viewing distance Z 0  in design is allowed to be longer; therefore, a load caused by glass grinding is allowed to be reduced. A viewing distance in the case where display with two perspectives is performed in the display is equal to a half of a normal preferred viewing distance Z 0  in design. On the contrary, a preferred viewing distance Z 0  in design is allowed to be twice as long as that in a typical stereoscopic display method with two perspectives (refer to  FIG. 3 ). 
     Other Embodiments 
     The present technology is not limited to the above-described embodiment, and may be variously modified. 
     For example, the technology is allowed to have the following configurations. 
     (1) A display including: 
     a display section including a plurality of first pixels to a plurality of nth pixels, where n is an integer of 4 or more, and displaying a plurality of perspective images assigned to the first to nth pixels; 
     a detection section detecting a view position of a viewer; and 
     a display control section varying the number of the plurality of perspective images assigned to the first to nth pixels and varying a correspondence relationship between the first to nth pixels and the perspective images, according to the view position of the viewer. 
     (2) The display according to (1), in which 
     when the view position of the viewer is located at a first distance from the display section, the display control section performs display control to partition the display section into a plurality of sub-regions and performs display control on pixels in each of the sub-regions, independently, thereby to vary the correspondence relationship between the first to nth pixels and the perspective images for each of the sub-regions. 
     (3) The display according to (2), in which 
     the plurality of perspective images are a right-eye image and a left-eye image. 
     (4) The display according to (3), in which 
     each of the sub-regions includes first pixels to nth pixels, and 
     the display control section assigns the right-eye image to two adjacent pixels of the first pixel to the nth pixel and assigns the left-eye image to other two adjacent pixels of the first pixel to the nth pixel, in each of the sub-regions. 
     (5) The display according to (4), in which 
     a combination of the two adjacent pixels to which the right-eye image is assigned in one sub-region is different from that in another sub-region, and a combination of the other two adjacent pixels to which the left-eye image is assigned in one sub-region is different from that in another sub-regions. 
     (6) The display according to (5), in which 
     when the view position of the viewer is located at the first distance, 
     the display control section assigns the right-eye image to the first and second pixels and assigns the left-eye image to the third and fourth pixels, in a first sub-region, and 
     the display control section assigns the right-eye image to the second and third pixels and assigns the left-eye image to the first and fourth pixels, in a second sub-region adjacent to the first sub-region. 
     (7) The display according to (6), in which 
     when the view position of the viewer is located at the first distance, 
     the display control section performs display control to allow luminance of the first pixel and the third pixel to be lower than that of the second pixel when a boundary portion between the first sub-region and the second sub-region is viewed from a right-eye position, and to allow luminance of the first pixel and the third pixel to be lower than that of the fourth pixel when the boundary portion is viewed from a left-eye position. 
     (8) The display according to any one of (2) to (7), in which 
     the display control section moves positions in a horizontal direction of the respective sub-regions in response to movement in a horizontal direction of the view position of the viewer. 
     (9) The display according to any one of (2) to (7), in which 
     the width of each of the sub-regions is equal to a pupillary distance. 
     (10) The display according to any one of (2) to (9), further including: 
     a separation section separating light beams from the first to nth pixels to allow the separated light beams to reach first to nth light-convergence regions located at a second distance from the display section, respectively, 
     in which when the view position of the viewer is located at the second distance, the display control section assigns first to nth perspective images as the plurality of perspective images to the first to nth pixels in an entire screen of the display section. 
     (11) The display according to (10), in which 
     the width of each of the first to nth light-convergence regions is equal to a pupillary distance. 
     (12) The display according to (10) or (11), in which 
     the first distance is equal to a half of the second distance. 
     (13) The display according to any one of (10) to (12), in which 
     when the view position of the viewer is located at the first distance, a right-eye image is assigned to pixels that correspond to the first to nth light-convergence regions and are viewable from a right-eye position, and a left-eye image is assigned to pixels that correspond to the first to nth light-convergence regions and are viewable from a left-eye position. 
     The present application contains subject matter related to that disclosed in Japanese Priority Patent Application 2011-068153 filed in the Japan Patent Office on Mar. 25, 2011, the entire content of which is hereby incorporated by reference. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations, and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.