Abstract:
Disclosed are various lenticular display systems that include either a color filter array (CFA) or a colored lens array that is spaced from the pixels of an underlying display panel. In an embodiment, the CFA of a lenticular display may be operable to provides a locally ‘static color’ reproduction of images as a function of viewing angle. It may also enable the resolution of the CFA to be relatively coarse. Both separating the CFA from the panel and reducing the resolution significantly may reduce the system cost and allow higher resolution to be realized.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Appl. Ser. No. 61/105,397, entitled “Autostereoscopic display with offset color filter array,” filed on Oct. 14, 2008, which is hereby incorporated by reference in its entirety for all purposes. 
     
    
     TECHNICAL FIELD 
       [0002]    The disclosed embodiments relate generally to lenticular display systems and, more specifically, to lenticular display systems comprising a color filter array in spaced relation with an underlying panel. 
       BACKGROUND 
       [0003]    Autostereoscopic displays have a long history dating back many decades. The basic principle of autostereoscopic display includes inserting a micro-optical array between a 2D display and the viewer so as to provide angularly dependent images. These underlying pixels include spatially-separated modulating elements of different colors (e.g. red, green, and blue). Relying on the refractive property of the lenses in the optical array, the optical array is operable to “hide” certain pixels at any given viewing angle and provide an image only with those pixels that remain visible. As such, the visible pixels are selectively chosen to create effective pixels for each view. 
         [0004]    Conventional autostereoscopic displays typically include a conventional LCD panel and a cylindrical lens array. Display pixels include a triad of rectangular red (R), green (G) and blue (B) subpixels aligned in contiguous columns. A cylindrical lens array is introduced directly in front of the display to provide multiple views by selectively imaging the pixels in the plane of the viewer. 
       SUMMARY 
       [0005]    Provided in the present disclosure is an exemplary embodiment of a lenticular display system including a display panel having a plurality of pixels operable to output light. The lenticular display system further includes a plurality of lenses disposed in the light paths of the light output by the plurality of pixels and a color filter array disposed between the plurality of pixels and the plurality of lenses, the color filter array may be adjacent to the plurality of lenses and spaced from the plurality of pixels. 
         [0006]    Another embodiment provided in the present disclosure is directed to a lenticular display system including a display panel having a plurality of pixels operable to output light. This embodiment further includes a plurality of colored lenses disposed in the light paths of the light output by the plurality of pixels, the plurality of colored lenses being in spaced relation with the plurality of pixels. 
         [0007]    The present disclosure also provides a method of manufacturing a lenticular display system, including providing a display panel having a plurality of pixels operable to output light. The method further comprises disposing a plurality of lenses in the light paths of the light output by the plurality of pixels and disposing a color filter array between the plurality of pixels and the plurality of lenses, the color filter array being adjacent to the plurality of lenses and spaced from the plurality of pixels. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Embodiments are illustrated by way of example in the accompanying figures in which: 
           [0009]      FIG. 1A  is a schematic diagram illustrating a slanted pixel array with an overlying cylindrical lenticular element, in accordance with the present disclosure; 
           [0010]      FIG. 1B  is a schematic diagram illustrating the effect of the cylindrical lenticular element, in accordance with the present disclosure; 
           [0011]      FIG. 2  is a schematic diagram illustrating front and top views of effective pixels as seen from different viewing angles, in accordance with the present disclosure; 
           [0012]      FIGS. 3A and 3B  are schematic diagrams illustrating top view cross-sections of a lenticular based autostereoscopic displays, in accordance with the present disclosure; 
           [0013]      FIG. 4A  is a schematic diagram illustrating a cross-sectional top view of an exemplary embodiment, in accordance with the present disclosure; 
           [0014]      FIG. 4B  is a schematic diagram illustrating a front view of the exemplary embodiment shown in  FIG. 4A , in accordance with the present disclosure; 
           [0015]      FIG. 5  is a schematic diagram illustrating front views of an alternate color mapping for underlying pixels, in accordance with the present disclosure; 
           [0016]      FIG. 6  is a schematic diagram illustrating a front view of an exemplary embodiment, in accordance with the present disclosure; and 
           [0017]      FIG. 7  is a schematic diagram of a cross-sectional top view illustrating an exemplary embodiment, in accordance with the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]      FIG. 1A  is a schematic frontal view of a lenticular autostereoscopic display system  100 . The basic operation of lenticular autostereoscopic display systems is provided herein with respect to the display system  100 . The display system  100  comprises a pixel array  102  and lenses  106  disposed over the pixel array  102 . In an embodiment, pixel array  102  may include pixels  104  that are slanted relative to the lenses  106  as illustrated in  FIG. 1A . In another embodiment, the pixel array  102  may include pixels  104  that are vertically aligned and the lenses  106  are oriented at an oblique angle relative to the vertically aligned pixels  104 . These oblique orientations of the pixels  104  relative to the lenses  106  allow for reducing angular and spatial intensity variation as explained in U.S. patent application Ser. No. 12/541,895, which is hereby incorporated by reference in its entirety for all purposes. 
         [0019]      FIG. 1B  is a schematic frontal view of the display system  100  having effective pixels  112 . In the illustrated embodiment, the slanted pixels  104  of the display system  100  may be viewed through the cylindrical lenses  106 , which selectively reveal some of the underlying pixels  104 . The resultant effective pixels  112  vary as a function of viewing position and angle, which provides angle-varying images for stereoscopic 3D visualization. Effective pixels  112  can be determined at any given angle from the projection of the lens center line  108  onto the pixel array  102 , as shown in  FIG. 1A . In operation, light  110  passing though the center of any lens does not get deflected and hence, the pixels  104  intersected by the projected center line  108  may be viewed as if the lenses  106  were not present. The remainder of the lens  106  deflects light from the same central regions toward the viewer, giving the impression of light stretched from the center to the lens edges and forming effective pixels  112 . In this manner, only the light  110  close to the projected center line  108  is seen. The pixels  102  not intersecting the projected center line  108  are hidden. 
         [0020]      FIG. 2  includes a schematic frontal view of a lenticular display system  200  and a corresponding schematic top view of the lenticular display system  200 .  FIG. 2  shows how the effective pixels  212  change as a function of the viewing position, and hence, the viewing angle. Geometry dictates the movement of the projected center lines  210  of the lenses  206  since the lenses  206  are spaced from the plane of the pixel array  202  at a fixed distance. This results in the effective pixels  212  shown in  FIG. 2  and illustrates the transition of the views as a function of viewing angle from 0°to θ, and from θ to 2θ. 
         [0021]    Different views appear continuously at different viewing angles until individual lenses image the pixels under their adjacent lenses, which would result in a replication of the views. The region containing a complete set of views is the “viewing zone.” The number of views within a viewing zone is substantially equal to the number of pixels that lie beneath a lens  206  in the horizontal direction. The size of viewing zone may be determined by the focal length of the lens  206 , but to provide stereoscopic images, at least two views may be included in the angle subtended by the viewer&#39;s eyes. A desirable large viewing zone is typically provided by increasing the number of pixels  204  beneath each lens  206  to increase the views. To provide for this, smaller and smaller pixels are being fabricated. 
         [0022]      FIG. 3A  is a schematic diagram illustrating a cross-sectional top view of a lenticular display system  300  with a RGB columnar color filter array (CFA)  302 . The CFA  302  may comprise any color filters known in the art and may be configured to provide the desired color mapping for the lenticular display system  300 . Here, the CFA  302  is configured such that colors alternate as a function of viewing angle. Lenses  306  may be disposed on a lens substrate  310  and may be positioned in the light paths  312  of light emanating from the underlying pixels  304 . To ensure that each pixel  304  corresponds to one of the alternating colors, the CFA  302  may be disposed immediately adjacent to the pixels  304  between panel substrates  308 . Such a close proximity of the CFA  302  and the pixels  304  may ensure that light passing through a pixel  304  would also pass through the color filter above it and may not leak into the color filter for adjacent pixel  304 . In other words, by properly aligning and disposing the CFA  302  adjacent to the pixels  304 , horizontal parallax can be substantially reduced. Properly aligning the CFA  302  with the underlying pixels  304 , however, is an expensive, low-yield step that may increase the cost of manufacturing the display system  300 . One method of reducing cost is to fabricate panels with contiguous color columns. 
         [0023]      FIG. 3B  is a schematic diagram of a cross-sectional top view of a lenticular display system  350  comprising a coarser CFA  352  that provides a ‘static color’ solution where color remains substantially the same at any given image pixel position for different viewing angles. In this embodiment, the underlying pixels may be grouped horizontally such that those situated directly beneath any one lens element output substantially the same colored light. This allows the effective pixels of the different angular views to retain substantially the same color at any given position, which may reduce the viewer&#39;s sensation of noise due to cycling of colors as a function of head position. Horizontal grouping of the pixels also may improve the ease of manufacturing and reduce the cost of the overall display system. Although the CFA  352  may be disposed immediately adjacent to the pixels  354 , it is to be appreciated that the reduction of horizontal parallax is much less of a concern regardless where the CFA  352  is placed. Indeed, due to the ‘static color’ configuration, horizontal parallax may be substantially reduced by the selective nature of the coarser CFA  352 . 
         [0024]      FIG. 4A  is a schematic diagram illustrating a cross-sectional top view of a lenticular display system  400  in accordance with the present disclosure, and  FIG. 4B  is a schematic diagram showing a frontal view of the lenticular display system  400 . The lenticular display system  400  includes a display panel  402  comprising a plurality of pixels  404  operable to output light along light paths  406 . The panel  402  may be a monochrome panel comprising monochrome pixels  404 , and the pixels  404  may be disposed between substrates  408 , which may be made of glass or other suitable materials, such as polymeric materials. The lenticular display system  400  may further include a lens sheet  410  proximate to the panel  402  for directing light from the pixels  404  to a viewer. The lens sheet  410  may include a plurality of lenses  412  disposed on a lens substrate  414  and may be oriented such that the lenses  412  are in the light paths  406  of the light output by the pixels  404 . 
         [0025]    To allow for colored light, an embodiment of the display system  400  may include a color filter array (CFA)  416  disposed between the pixels  404  and the lenses  412 . The CFA  418  may be configured to allow “static color” with coarse effective pixels  418 . As such, the leakage of light between the CFA  416  and the pixels  404  may not compromise the performance of the display system  400 , and accordingly, the CFA  416  may be disposed adjacent to the lenses  412  and spaced from the pixels  404 . This embodiment may allow for the elimination of the costly, low-yield step of disposing the CFA  416  immediately next to the pixels  404  and aligning CFA  416  and the pixels  404 . 
         [0026]    In another embodiment, the lenses  412  of display system  400  may themselves be filtered (i.e., colored) by applying RGB stripes of conventional absorbing filter material directly beneath the lens array. In one exemplary embodiment, a single stripe may be associated with each cylindrical lens element. 
         [0027]    In some embodiments, the pixels  404  of the display system  400  may include light-modulating elements, such liquid crystal cells. The pixels  404  may be oriented at oblique orientations as shown in  FIG. 4B . For example, a pixel array of the display system  400  may comprise a plurality of pixels  404  arranged in a plurality of rows and columns according to a Herring-bone pattern. 
         [0028]    In the embodiment illustrated in  FIG. 4B , the horizontal pitch of the pixels px would be ˜lp/(3(N−δ)), where lp is the lens pitch and therefore the effective horizontal pixel pitch, and N is the number of views in the viewing zone. δ is typically close to 0.5 in order to reduce unwanted pattern noise in the form of moire fringes and is dependent on specific pixel structure. In some embodiments, vertical pixel pitch py may be equivalent to the lens pitch lp to provide square effective pixels. The oblique angle θ of the pixels may be between 
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         [0000]    with the exact angle chosen again to remove moire effects. To avoid spatial color breakup, the lens pitch may be typically less than 0.3 mm for a 60″ diagonal display. Using current lithography techniques, the horizontal pixel pitch of the panel can be as small as 10 μm, making the approximate total number of views to be 30, which is compatible with a viewing zone of approximately 40°. 
         [0029]      FIG. 5  is a schematic view of the color mapping of two display systems  500  and  550 . Display system  500  comprises a slanted-pixel panel structure with a CFA immediately adjacent to the panel. The color mapping of the display system  500  is the uniform colored effective pixels  502  as discussed above. The display system  550  comprises grey monochrome pixels overlayed by filtered lenses. As shown in  FIG. 5 , the effective pixels  552  of the display system  550  is substantially equivalent to the effective pixels  502 . This equivalence allows the CFA to be defined in the plane of the lenses without appreciable performance reduction within the viewing zone while providing significant cost advantages. 
         [0030]    Outside the viewing zone, pixels situated behind any given colored lens are seen through adjacent lenses. Since alternate colored lenses are proposed, this would result in color distortion in the displayed images. For embodiments based on future applications, this may not constitute a problem as the viewing zone is expected to be sufficient for any reasonable viewing environments with super-high resolution panels. For embodiments incorporating currently available panels, the onset of color distorted images would alert the viewer to be repositioned within the viewing zone and could be beneficial for preventing viewing of the confusing images displayed at viewing zone boundaries. For embodiments directed to single-viewer systems, correction data could be applied to the underlying pixels based on the viewer&#39;s position, substantially avoiding all such issues. For example, a lenticular display system of the present disclosure may include a controller for receiving the data related to a viewer&#39;s position and display images based on the viewing zone corresponding to the viewer&#39;s position. In one exemplary embodiment, the controller of the lenticular display system may receive data from a head tracking device. This approach is particularly suitable for systems that allow complete look-around capability without the overhead of displaying multiple images simultaneously and reduces the underlying panel resolution. 
         [0031]      FIG. 6  is a schematic diagram showing a frontal view of an exemplary embodiment of a lenticular display system  600 . The lenticular display system  600  includes a display panel  602  comprising a plurality of pixels  604  operable to output light along light paths. The panel  602  may be a monochrome panel comprising monochrome pixels  604 . The lenticular display system  600  may further include a lens sheet  606  proximate to the panel  602  for directing light from the pixels  604  to a viewer. The lens sheet  606  may include a plurality of lenses  608  and may be oriented such that the lenses  608  are in the light paths of the light output by the pixels  604 . To allow for colored light, an embodiment of the display system  600  may include a CFA (not shown) disposed between the pixels  604  and the lenses  608 . The CFA may be disposed adjacent to the lenses  608  and spaced from the pixels  604 . In another embodiment, the lenses  608  of display system  600  may themselves be color-filtered. 
         [0032]    In the illustrated exemplary embodiment, the pixels  604  are arranged in a pixel array comprising a plurality of rows and columns, and lenses are arranged in a lens array having a plurality of rows and columns that are aligned at oblique angles relative to the rows and columns of the pixel array. In other words, the lens sheet  606  may be tilted relative to the pixels  604  to hide the global imaging of pixel boundaries. 
         [0033]      FIG. 7  is a cross-sectional view of an exemplary embodiment of a lenticular display system  700  in accordance with the present disclosure. The lenticular display system  700  may include a display panel  702  comprising a plurality of pixels  704  operable to output light along light paths  706 . The panel  702  may be a monochrome panel comprising monochrome pixels  704 . The lenticular display system  700  may further include a lens sheet  708  proximate to the panel  702  for directing light from the pixels  704  to a viewer. The lens sheet  708  may include a plurality of lenses  710  and may be oriented such that the lenses  710  are in the light paths of the light output by the pixels  704 . 
         [0034]    To allow for colored light, an embodiment of the display system  700  may include a coarse  712  CFA disposed between the pixels  704  and the lenses  710 . The CFA  712  may be disposed adjacent to the lenses  710  and spaced from the pixels  704 . In another embodiment, the lenses  710  of display system  700  may themselves be filtered. In an embodiment, the display  700  may include a second color filter array  712  disposed between the pixels  704  and the plurality of lenses  710 , and adjacent to the pixels  704  for secondary viewing zone suppression. This embodiment may allow suppression of incorrect viewing zones through complimentary filtering. Light passing through dissimilar filters may be highly attenuated effectively hiding viewing zones showing incorrect images. 
         [0035]    While various embodiments in accordance with the principles disclosed herein have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the invention(s) should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with any claims and their equivalents issuing from this disclosure. Furthermore, the above advantages and features are provided in described embodiments, but shall not limit the application of such issued claims to processes and structures accomplishing any or all of the above advantages. 
         [0036]    Additionally, the section headings herein are provided for consistency with the suggestions under 37 CFR 1.77 or otherwise to provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure. Specifically and by way of example, although the headings refer to a “Technical Field,” the claims should not be limited by the language chosen under this heading to describe the so-called field. Further, a description of a technology in the “Background” is not to be construed as an admission that certain technology is prior art to any invention(s) in this disclosure. Neither is the “Summary” to be considered as a characterization of the invention(s) set forth in issued claims. Furthermore, any reference in this disclosure to “invention” in the singular should not be used to argue that there is only a single point of novelty in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims issuing from this disclosure, and such claims accordingly define the invention(s), and their equivalents, that are protected thereby. In all instances, the scope of such claims shall be considered on their own merits in light of this disclosure, but should not be constrained by the headings set forth herein.