Abstract:
A flat panel display structure is disclosed that can support significant loads on the viewing surface without fracturing or permanently damaging the video display. A rigid body is fitted in a peripheral frame and situated behind the viewing surface. When a load is applied to the video display, the load is transferred to the rigid body, which absorbs and distributes the load to the peripheral frame.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. Provisional Patent Application Ser. No. 61/193,103, filed on Oct. 28, 2008, the contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to flat panel displays. 
       DESCRIPTION OF THE PRIOR ART 
       [0003]    Flat panel displays, such as Liquid Crystal Displays (LCDs), have become a popular choice for displaying video. Such displays are generally much thinner and lighter than traditional video displays that employ cathode ray tubes, and are therefore suited for a wide variety of applications. 
         [0004]    Traditionally, flat panel displays have been mounted in a vertical position for use in products such as televisions, computers, billboards, and the like. Such displays do not expect, and are not designed to accommodate significant loads on their viewing surface. However, it is becoming increasingly popular to consider utilizing flat panel displays in applications in which the display is mounted in a non-vertical position. For example, the flat panel display may be integrated into a floor space to be used for advertising in shopping centers, or it may be integrated into a table top to provide information or entertainment to patrons occupying the table. In such applications, the display device would be expected to accommodate significant loads on or above the viewing surface. Such loads could be dynamic (e.g., pedestrians walking on the display), or could be static (e.g., books, glasses, etc. being placed on the display). 
         [0005]    Flat panel displays currently used in such applications generally rely on an external housing structure with the display located within the housing. This acts to protect the viewing surface from direct loading. For example, U.S. Pat. No. 7,145,469 discloses an electronic display device housed within an external supporting structure, which is capable of being placed on a horizontal surface and walked over. The disadvantage of using an external housing structure is that the viewing window is generally comprised of relatively thick glass or plastic, which results in a poor viewing experience due to the problems of parallax and limited viewing angle. In particular, the thicker the protective surface, the greater the refraction of light, and hence the greater the parallax. Such a visual offset diminishes the effectiveness of the display, 
         [0006]    U.S. Pat. No. 5,606,438 discloses a ruggedized LCD in which a rigid transparent material such as acrylic is mounted across the back face of the LCD. This arrangement however is provided to enhance the integrity of the display itself but does not contribute to its ability to resist loads in a direction normal to the viewing area. 
         [0007]    Many of the LCDs available require backlighting to provide a display with acceptable clarity and visibility. The backlighting is often provided by fluorescent tubes located behind the LCD. Such tubes are inherently fragile and easily damaged if loaded directly by external forces. However, any protective structure used to protect the tubes may also introduce obstructions that interfere with uniform backlighting of the LCD. 
         [0008]    It is an object of the present invention to provide a structure in which at least one of the above disadvantages is obviated or mitigated. 
       SUMMARY OF THE INVENTION 
       [0009]    In general terms, the following provides a flat panel display structure that can support significant loads on the viewing surface without fracturing or permanently damaging the video display. 
         [0010]    In one embodiment, there is provided a flat panel video display comprising a peripheral frame having opposite side members and a base extending between the side members to define a housing. A rigid body fitted in the housing and supported by the peripheral frame. One or more video display layers are stacked on the rigid body and supported across the extent of the base by the rigid body, such that when a load is applied to the surface of the video layers, the force of the load is transferred to the rigid body and distributed to the peripheral frame. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Exemplary embodiments will now be described by way of example only with reference to the accompanying drawings, in which: 
           [0012]      FIG. 1  is a perspective view of a flat panel video display device in which video display layers of the stack are exposed; 
           [0013]      FIG. 2  is a cross-sectional view along line A-A of  FIG. 1 ; and 
           [0014]      FIG. 3  is an alternative embodiment of the flat panel display device shown in  FIGS. 1 and 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Referring therefore to  FIGS. 1 and 2 , a flat panel video display structure  10  has a peripheral frame  12 . The frame  12  has opposite side members  14 ,  16  and a base  18  extending between the side members  14 ,  16  to define a housing. The frame  12  and base  18  may be made from a reinforced resin that is molded to shape or may be fabricated from sheet material if preferred. 
         [0016]    The side members  14 , 16  each have inwardly directed faces  20 ,  22  that are inwardly inclined toward the base  18 . A recess  24  is formed around the upper edge of the side members. 
         [0017]    The frame  12  accommodates a backlit liquid crystal display (LCD) unit. The unit has an LCD  28  that is standard in the art and includes a liquid crystal layer sandwiched between two polarizing filters. The LCD  28  further includes a transparent front protective sheet  34  such as thin glass. 
         [0018]    The edges of the protective sheet  34  are supported in the recess  24  so as to be flush with the upper surface of the frame  12 . 
         [0019]    If necessary, situated behind the LCD  28  is a light transmissive layer of material  36  for filling any void that may be present in the stack, for example due to the shape of frame  12 . As an example, filling material  36  may comprise elastomer, glass, or virtually any other suitable material that is light transmissive. As will be described below, the purpose of the filling material  36  is to fill any voids in the stack so that there are substantially no voids between the LCD  28  and the rigid support  40 , such that when a load is applied to the LCD  28 , it may be transferred to the support  40 . 
         [0020]    Behind the layer of filling material  36  are one or more layers of diffusers  38 . Such diffusers  38  are well-known in the art and are utilized to diffuse the backlight such that the intensity and/or brightness of the backlight is uniform across the back of the LCD  28 . The number of layers of diffusers  38  will vary depending on the LCD  28  and may be reduced or eliminated depending on the amount of diffusion provided by rigid support  40  (as will be explained below). Three layers of diffusers  38  are shown in  FIG. 1  for illustrative purposes only. 
         [0021]    Located behind the diffusers  38  is a light transmissive rigid support  40  made of a rigid body. The support  40  has a planar top surface  42  in engagement with the diffusers  38  and a rear surface  44  abutting the base  18 . The rear surface  44  has part cylindrical channels  46  integrally formed and house fluorescent bulbs or tubes  48 , which supply backlighting. The fluorescent tubes  48  are mounted to the backlighting unit (not shown), as is standard in the art. 
         [0022]    The outer edges  50 ,  52  of the support  40  are sloped inwardly so as to be complementary to the inwardly directed faces  20 ,  22  of side members  14 ,  16 . When the support  40  is installed, the edges  50 ,  52  snugly engage the faces  20 ,  22  as the rear surface  44  engages the base  18 . 
         [0023]    The support  40  is thus fully supported around its edges  50 ,  52  by the frame  12  and is positioned to provide support across the full area of the LCD  28 . The protective glass sheet  32 , LCD  28 , optional filling material  36 , and diffusers  38  are also supported by the recess  24  around the periphery of the frame  12 . The channels  46  also provide protection for the tubes  48 . 
         [0024]    Advantageously, the material of the support  40  may be chosen to have the desired optical characteristics that allow the light from the tubes  48  to be diffused and/or uniformly distributed across the diffusers  38 . For example, a surface finish may be added into the mold used to form the support  40  or applied after the casting process to facilitate diffusion of the backlighting as the light from the backlighting it transmitted through and/or exits support  40 . Such a finish may be provided by sand blasting, casting, acid etching, or any other techniques that create the desired diffusing effect. Whilst not required, such a finish complements the diffusers  38  in the stack and helps ensure that the light intensity and/or brightness is uniform across the back of the video display. It may even be possible to reduce or eliminate the diffusers  38  in some embodiments. 
         [0025]    In use, when a load is applied to the display structure  10  in a direction normal to the LCD  28 , for example, when a pedestrian walks on the protective sheet  34 , the load is transferred through layers  36  and  38  to the rigid support  40 , which acts to absorb and distribute the load uniformly to the base  18  and sides  14 ,  16  of the frame. The provision of the support  40  integrated into the stack of the flat panel display  10  allows the display to support significant loads without utilizing an external support or housing. This avoids the disadvantages associated with an external support structure, such as having an external viewing window of thick glass or plastic covering the display. Also, such a structure is particularly well-suited to embodiments in which touch-screen applications are supported since the touch screen sensor may he placed directly on the display device itself. 
         [0026]      FIG. 3  shows an alternative embodiment in which like components are denoted by like reference numerals with a suffix ‘a’ added for clarity. In this embodiment, the base  18   a  of frame  12   a  does not bear any of the load applied to support  40   a.  Instead, support  40   a  acts like a beam and transfers the full force of its load to the sides  14   a,    16   a  of the frame  12   a.  This is achieved by sloping the inwardly directed faces  20   a,    22   a  of frame  12   a  and cooperating outer edges  50   a,    52   a  of support  40   a  to prevent the support  40   a  from abutting base  18   a.  Therefore, when a load is applied, the support  40   a  acts to distribute the load uniformly to sides  14   a,    16   a  of the frame  12   a.  In this embodiment, backlighting (not shown) and/or other components may be placed in void  54  between base  18   a  and support  40   a.    
         [0027]    It will be understood that in the above-described embodiments, the panel display  10  will incorporate the normal controls and power supplies within the construction, but that these have been omitted for clarity. 
         [0028]    Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing from the spirit and scope of the invention as outlined in the claims appended hereto. 
         [0029]    For example, the specific arrangement of the layers of the stack described above is only one particular way of arranging the layers, It will be appreciated that the stack layers may be arranged differently without departing from the spirit or scope of the invention, provided that the provision of the rigid support  40  is included to absorb any load applied to the display structure  10 . As an example, one may wish to have an LCD polarizing filter sandwiched between two layers of diffusers. Such a modification, and others of a similar nature, do not affect the object of the invention, 
         [0030]    It will be appreciated that the rigid support  40  may be applied to a variety of video display technologies that are utilized in flat panel display stack systems. For example, in a flat panel display using plasma video display technology, the support  40  is situated behind the plasma display layer with (if necessary) appropriate filling material  36  intermediate the plasma display and the support  40 . In operation, the support  40  provides the same functionality as when an LCD is used, that is as a load is applied to the plasma display, the force is transferred through the filling material  36  (if present) and to the support  40 , which acts to distribute the load uniformly to the frame  12 . To this end, it will be appreciated that the provision of the rigid support  40  is independent of the video display technology and therefore may be integrated into a wide variety flat panel video displays.