Abstract:
A display system, a method of constructing a display system, and a method of displaying an image are provided. In one embodiment, a display system includes a support structure having a plurality of attachment members and a plurality of tiles. Each of the plurality of tiles is attached to a corresponding attachment member of the plurality of attachment members. The support structure is configured to structurally support each of the plurality of tiles, and at least one of the plurality of tiles includes at least one connection configured to removably connect and align the at least one of the plurality of tiles with another one of the plurality of tiles.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation of U.S. patent application Ser. No. 12/424,338, filed Apr. 15, 2009, issued as U.S. Pat. No. 8,384,616 on Feb. 26, 2013, which claims priority to U.S. provisional application 61/045,230, filed Apr. 15, 2008, which are incorporated by reference. 
     This application is also related to U.S. patent application Ser. No. 12/424,360, filed Apr. 15, 2009, issued as U.S. Pat. No. 8,007,121 on Aug. 30, 2011, which is incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This disclosure generally relates to display units and particularly to a display system comprising groups of light emitting elements mounted to a support structure such that the display system may be easily installed and/or reconfigured while retaining both strength and positional accuracy. 
     Display systems for entertainment, architectural, and advertising purposes have commonly been constructed of numbers of light emitting elements such as LEDs or incandescent lamps mounted onto flat tiles. The light emitting elements can be selectively turned on and off to create patterns, graphics, and/or video displays for both informational and aesthetic purposes. It is well known to construct these displays as tiles or large panels which are assembled in position for a specific entertainment show or event or as an architectural or advertising display. Examples of such systems are disclosed in U.S. Pat. Nos. 6,813,853, 6,704,989, and 6,314,669, the disclosures of which are incorporated by reference herein for all purposes. 
     It can be a requirement of an event or theatrical production to use such a display but to have the display easily removable, for example in between scenes of a play or theatrical event, as the needs of the production dictate. Systems may use a tile based structure where a tile, typically around 2 ft×2 ft, can be lifted by hand and positioned. Accurate positioning of the tiles may be a time consuming and complex process involving skilled personnel. 
     Displays of these types may be constructed at different resolutions where the spacing between the light emitting elements can be varied. It may also be a requirement to change this spacing at different points on the display. Such systems are disclosed in U.S. Pat. Nos. 5,410,328, 7,102,601 and 7,071,620, the disclosures of which are incorporated by reference herein for all purposes. Further prior art systems, such as the VersaPixel manufactured by Element Labs, Inc. or the MiSphere system manufactured by Barco, may use suspended light emitting elements to be used as a ceiling or roof to an area. It would be advantageous to have a support and installation structure for such displays that is simple to install and that facilitates use in differing resolutions and on different planes through a single structure. 
     Small errors in the positioning of the pixels within tiles and tiles within a display can be cumulative and may lead to large errors in overall pixel alignment accuracy. At the same time the display support system must be strong enough to support a large area of display tiles and to withstand side loads from wind and weather if used outside. The goal of simultaneous strength, rigidity and accuracy is one that is commonly not achieved in prior art systems and the user typically has to accept a reduced accuracy in order to achieve the required strength. Accordingly, there exists a need for a display system that may be easily installed and/or reconfigured while retaining both strength and positional accuracy. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows pixels of a prior display system. 
         FIG. 2  shows a portion of a prior modular display system. 
         FIG. 3  shows a prior modular display system. 
         FIG. 4  shows a display system in accordance with embodiments of the present disclosure. 
         FIG. 5  shows an isometric view of a tile of a display system in accordance with embodiments of the present disclosure. 
         FIG. 6  shows a rear view of a tile of a display system in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows pixels of a display system in accordance with the prior art. Each pixel  101   a ,  101   b ,  101   c ,  101   d  may be constructed from three LEDs; e.g., red (R), green (G) and blue (B). The distance  103  and  102  between the center of a pixel and its adjacent pixels is referred to as the pixel pitch. The x-axis pixel pitch  103  may be substantially the same as the y-axis pixel pitch  102 . 
     In a large display with a large number of pixels it is critical that the pixel pitch is controlled within tight tolerances. Errors in the pixel pitch across the display are very apparent to the viewer and adversely affect the image quality. 
       FIG. 2  illustrates a portion of a modular display system  110  in accordance with the prior art, where display modules  112 ,  114 ,  116 ,  118  are mounted adjacent to each other to form a single display. Methods to control pixel alignment and pitch within a single module are well known in the art through such means as accurate component placement on a printed circuit board within the module housing. The modules may be constructed from plastic, and be sufficiently small that the tolerances within the modules can be tightly controlled. 
     However the pitch  119  between the pixels on adjacent modules is controlled by the accurate mechanical alignment and spacing of the individual modules. If this alignment and spacing is not accurately maintained gaps may appear in the display which appear darker when the screen is set to black. Additionally, banding can appear due to perceived luminance errors. For example, if the pixel pitch between modules is greater than the pixel pitch within the module, then the effective area subtended to the viewer by the pixels at the boundary is larger than those within the module. This increased effective area causes the perceived luminance of the pixels at the boundaries of the modules to be lower than the pixels within the module causing an apparent band or stripe in the image. 
     In the prior art, modular display systems may include a number of display modules mounted onto a larger tile in which these tiles are connected together to form the entire screen. The tiles are typically constructed from folded sheet metal, and are large compared to the modules. These tiles and their interconnection provide both the alignment of the display modules and the structural support and strength to form the mechanical infrastructure of the screen. If a screen is intended for an outdoor application then it must further be able to withstand wind loadings producing significant sideways forces. 
       FIG. 3  shows a modular display system in accordance with the prior art. A plurality of display modules  124  are assembled onto a support structure  126  to form tile  120 , and a second plurality of display modules  130  are assembled onto support structure  128  to form a second tile  122 . Support structures  126  and  128  are interconnected to support and align the two tiles. The alignment of the display modules  124  on tile  120  with display modules  130  on tile  122  are affected by multiple and cumulative tolerances: tolerance  2  between tile  120  and support structure  126 , tolerance  4  between support structure  126  and support structure  128 , and tolerance  6  between support structure  128  and tile  122 . 
     In the prior art system such tolerances may accumulate and produce a total positional error as high as ±8.25 percent (total 16.5 percent) resulting in visible and objectionable luminance difference between the pixels at the tile boundaries and the pixels within the tile. Such a gap between tiles will be noticeable to an observer and detract from a cohesive look. Although here we are referring to tolerances in a single axis, it is also important to note that these tolerances may be present and important in all three perpendicular axes x, y, and z. 
     The prior art uses the support structure  126 ,  128  to provide both: 
     alignment—ensuring that the tiles align to form a cohesive display; and 
     structural support—ensuring that the screen can support itself safely as well as endure additional forces, such as from wind loading in outdoor situations. 
     Alignment accuracy is the primary requirement for display quality, but the large structural parts needed to simultaneously achieve the strength goals may hinder that accuracy. Achieving the tight tolerances needed with large structural components can be difficult and expensive, and almost always involves large amounts of time consuming and expensive machining. 
     The present disclosure improves on the prior art and discloses means for assembling a modular display which isolate the alignment and structural requirements/functionality from each other.  FIG. 4  shows a display system  150  in accordance with embodiments of the present disclosure. Multiple display modules  124  are assembled onto a plurality of tiles  120  (without the use of support structures  126 ,  128 ). Tiles  120  may connect to adjacent tiles through at least one connection that may include clips or clamps which provide accurate and improved alignment without having a requirement (or a substantially low requirement) to provide support or strength to the system. Substantially removing the strength requirement from these components allows smaller, more accurately manufactured parts to be used and ensure highly accurate alignment. The tiles may be manufactured using injection molding or other techniques well known in the art which have inherently high levels of accuracy, as compared to the sheet metal and machining techniques used in the prior art. Thus, the video display will be accurately aligned and cohesive in its appearance. 
     Structural support and strength is provided though a secondary structural support  152  which is connected to the display tiles through attachment member  154  such that the alignment of the display tiles remains uncompromised. In one example, attachment member  154  includes an interconnecting member, such as a rod, and a spigot at the end of the rod, which operably couples to a tile  120 . The secondary structural support  152  provides the strength required to support itself and the display tiles and to resist other applied forces such as wind loading. 
     To ensure that any inaccurate alignment of structural support  152  does not compromise or affect the alignment of the display tiles  120 , the attachment members  154  may be constructed so as to take up or nullify any tolerance difference between the accurately aligned display tiles  120  and the structural support  152 . Alignment accuracies up to an order of magnitude better than the prior art system can be provided by the separation of the functions of alignment and support. For example, in one embodiment, the attachment member  154  may be moveable or deformable in any direction with respect to the structural support  152 . 
       FIG. 5  shows an isometric view of a tile  160  of a display system in accordance with embodiments of the present disclosure. A plurality of pixels  166  are mounted onto a display tile  160 . Display tile  160  is accurately constructed to very tight tolerances and may use injection molding or other inherently accurate manufacturing technique. The strength requirement for tile  160  is minimal, as it only needs to support itself and the attached pixels and associated circuitry. There is no requirement to provide support for adjacent tiles. Alignment between adjacent tiles  160  is provided through connections such as clips  162  and receptacles  164  in one example. Clips  162  and receptacles  164  provide highly accurate alignment of adjacent tiles  160  with no or a substantially low requirement to transmit support or strength between those tiles. This allows the use of accurate construction to very tight tolerances which may use injection molding or other inherently accurate manufacturing technique. 
       FIG. 6  shows a rear view of a tile of a display system in accordance with embodiments of the present disclosure. Clips  162  on the top of a tile may connect to receptacles  165  on the bottom of the adjacent tile. Similarly clips  163  on the right of a tile may connect to receptacles  164  on the left side of the adjacent tile. Strength and support for tile  160  is provided through center attachment point  168  which connects to the attachment member  154  ( FIG. 4 ) back to the structural support  152  ( FIG. 4 ). Through such means a modular display of any size may be quickly and accurately constructed. 
     In certain embodiments, the tiles (e.g., tiles  120  or  160 ) may include a Printed Circuit Board (PCB) that allows a plurality of light emitting elements to be electronically connected to the tile. Further, in certain embodiments, the display system  150  ( FIG. 4 ) may also include a power unit and/or a main processor that is electronically connected to the plurality of light emitting elements. As such, the power unit and/or the main processor may send a data and/or power signal to the plurality of light emitting elements disposed on the tiles. Based on the power signal, the plurality of light emitting elements may be selectively powered on and off or emit light with varying intensities, and based on the data signal, the plurality of light emitting elements may selectively emit light of different colors. 
     Advantageously, the present disclosure provides a comprehensive display system and support structure capable of providing both strength and rigidity while also presenting a high level of accuracy for tile and pixel placement. 
     This description of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications. This description will enable others skilled in the art to best utilize and practice the invention in various embodiments and with various modifications as are suited to a particular use. The scope of the invention is defined by the following claims.