Abstract:
A lighted display panel includes a plurality of illumination layers, with each layer having leading and trailing edges. Each of the layers has a cross section in which the leading and trailing edges are angled toward an upper or lower face of the layer. In some cases, the leading and trailing edges are offset from one another. In other cases, the illumination layer has a wing shape. Lighting elements (e.g., LEDs) are located in the leading edges of the illumination layers. The illumination layers define vents through which air may flow, but which obstruct the passage of light.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application Ser. No. 60/651,204, filed Feb. 10, 2005 and titled “Aerodynamic Lighted Display Panel,” which application is incorporated by reference herein. 

   FIELD OF THE INVENTION 
   The invention relates generally to lighted displays and signs that display custom messages, such as LED panels and the like. More specifically, the invention provides an aerodynamic array configuration for a display panel, thereby reducing wind resistance of the panel. 
   BACKGROUND OF THE INVENTION 
   Lighted display panels, such as LED panels and the like, are used for a variety of purposes, including providing traffic information via signs over highways or in subway stations, scrolling various messages across single or multi-color displays, and presenting information or replays during sporting events in large arenas, among other uses. Lighted display panels are well known in the art, and many patents have been granted for various aspects of their design. 
   However, a common problem in the art is that known lighted display panels inherently have high wind resistance due to their solid surfaces and their considerable sizes that are needed to be visible from long distances. It would thus be an advancement in the art to provide a physical housing configuration, or form factor, for a lighted display panel that provides venting or other physical characteristics to allow wind and elements to pass through the lighted display panel. 
   SUMMARY 
   This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
   In at least some embodiments, a lighted display panel may include a display housing enclosing two or more separately enclosed separated layers of linearly arranged lighting elements. The layers are spaced apart to form a channel through which air can pass, and each layer may include an enclosed layer housing having a leading edge, a trailing edge, a top surface, and a bottom surface, with the leading edge offset from the trailing edge. An intended viewing angle of the display panel may be incident to a top or bottom surface. 
   In other embodiments, each enclosed layer housing may have an airfoil-shaped cross-section. The leading edge and the trailing edge may recede into portions of the layer having equal or different heights. In each layer the linearly arranged lighting elements may be equally spaced. 
   In still other embodiments, a lighted display panel may further include one or more support plates arranged vertically in the display panel where the normal of each support plate is substantially parallel along the length of each layer. The support plate may have cutouts in a shape of the cross-section of each layer thereby providing vertical support within the display panel. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete understanding of the present invention and the advantages thereof may be acquired by referring to the following description in consideration of the accompanying drawings, in which like reference numbers indicate like features, and wherein: 
       FIG. 1  illustrates a cross-sectional view of a light housing that may be used according to an illustrative embodiment of the invention. 
       FIG. 2  illustrates a cross-sectional view of another light housing that may be used according to an illustrative embodiment of the invention. 
       FIG. 3  illustrates a cross-sectional view of yet another light housing that may be used according to an illustrative embodiment of the invention. 
       FIG. 4  illustrates a cross-section of a plurality of the light housings illustrated in  FIG. 1 . 
       FIG. 5  illustrates a cross-section of a plurality of the light housings illustrated in  FIG. 2 . 
       FIG. 6  illustrates an aerodynamic lighted display panel according to an illustrative embodiment of the invention. 
   

   DETAILED DESCRIPTION 
   In the following description of the various embodiments, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration various embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. 
   Aspects of the invention provide an aerodynamic display panel that allows wind and rain to pass through openings or vents in the display panel housing, while still maintaining sufficient contrast to distinguish lit and unlit lighting elements of the display panel forming a message to viewers of the display panel. As described in more detail below, the aerodynamic display panel comprises a plurality of stacked layers, louvers, or wings with sufficient space between layers to provide flow-through vents through which air, rain, and other elements may pass. The layers are shaped in such a manner such that, when viewing the display panel from a typical or intended viewing angle, a viewer cannot see through the flow-through vents, which would cause the viewer to see whatever is behind the display panel, thus causing confusion or an inability to read a message displayed on the display panel. Instead, layers are shaped in such a manner that a viewer sees the housing of the layer above or below the vent, thereby providing sufficient contrast for viewing a message displayed on the display panel. 
     FIG. 1  illustrates a cross-section of a layer  101  that may be used according to an illustrative embodiment of the invention. The dimensions in  FIG. 1  are provided in inches. The cross-sectional view of layer housing  102  illustrates only a single lighting element  103 , e.g., a light emitting diode (LED), located at the position of the cross-section. However, each layer preferably houses a plurality of lighting elements  103  such that when a plurality of layers are configured as described herein, the result is an array of lighting elements as illustrated in  FIG. 6 . While LEDs are commonly used in display panels, any type of lighting element may be used, as is known in the art. In addition, each lighting element may comprise a plurality of individual lights to provide multiple colors or different brightness levels. Electrical circuitry of the display panel may run through a hollow interior  111  of housing  102 , and housing  102  is preferably completely enclosed or encapsulated to provide protection of the electrical components from environmental hazards (e.g., weather, dirt, sand, smog, chemicals, etc.). 
   Layer housing  102  may include one or more horizontal support receivers  105  and/or one or more vertical support receivers  107 . A dowel, rod or other support beam may be inserted through vertical support receiver  107  and/or horizontal support receiver  105  to hold the layer  101  in position and/or provide rigidity to the layer  101  where the layer housing is otherwise constructed of a flexible material. Each support beam may be attached at either end to a display housing  603  ( FIG. 6 ). Layer housing  102  is preferably dark in color to provide contrast to the lighting elements  103  of each layer. A leading edge  108  of each layer housing  102  may be clear or otherwise translucent to allow each lighting element  103  to be visible external to the display panel. 
   Layer housing  102  is preferably configured such that the layer turns, curves, or arcs in a direction crossing an intended viewing angle  109  of the display panel, thus making layer housing  102  incident to the intended viewing angle. While the layer housing  102  could ultimately cross the intended viewing angle by turning in either of two directions (i.e., up or down), the layer housing  102  preferably turns, curves, or arcs in the direction requiring the smallest turn angle in order to cross the intended viewing angle in a given amount of space. For example, most display panels are viewed horizontally or from an angle below horizontal (i.e., the viewer is typically even with or at a lower elevation than the display panel), thus each layer housing  102  should turn, curve or arc downward from its leading edge  108  such that the trailing edge  110  is offset below the leading edge  108 . In the instances where the display panel is viewed from above, each layer housing  102  may turn, curve or arc upward from its leading edge  108 . A trailing edge  110  of the layer housing  102  may be configured such that wind passing from behind the display panel can pass with the same reduced resistance as from the front of the display panel. The distance from leading edge to trailing edge is referred to as the layer width, whereas the thickness of each layer is referred to as the layer height. The length of each layer is the distance from one side of the display panel to the other, and it is the distance that primarily limits the number of lighting elements that may be housed in each layer. The form factor illustrated in  FIG. 1  creates equal wind loading in either wind direction, i.e., front to back and back to front. 
     FIG. 2  illustrates a cross-section of an alternative form factor that may be used according to an illustrative embodiment of the invention. In  FIG. 2 , layer  201  has a dark colored, wing-shaped housing  202  having hollow interior  211 , lighting elements  203  (only one shown), horizontal support receivers  205   a ,  205   b , leading edge  208  with a clear or translucent cover, and trailing edge  210 . In  FIG. 2 , an intended viewing angle  209  is similar to that of  FIG. 1 .  FIG. 2  illustrates a configuration using two horizontal supports and no vertical supports. 
     FIG. 3  illustrates a cross-section of an alternative form factor that may be used according to an illustrative embodiment of the invention. The dimensions in  FIG. 3  are provided in inches. In  FIG. 3 , layer  301  has a dark colored, S-wedge housing  302  having hollow interior  311 , lighting elements  303  (only one shown), horizontal support receiver  305 , leading edge  308  with a clear or translucent cover, and trailing edge  310 . In  FIG. 3 , an intended viewing angle  309  is similar to that of  FIG. 1 .  FIG. 3  illustrates a configuration using only a single horizontal support and no interior vertical supports (vertical support is provided at either end of layer housing  302 , or using support plates  609 , further described below and shown in  FIG. 6 ). 
   In any of the embodiments illustrated in  FIGS. 1-3 , vertical supports  107  as described above might not be used, and instead optionally replaced with one or more pieces of vertical sheet metal (e.g., 0.80″ thick aluminum sheet) plates  609  ( FIG. 6 ) in which holes are cut equal to the outer profile (cross-sectional shape) of the layer with the desired vertical pitch (in one embodiment, 0.69″). In embodiments using vertical plates  609 , the number of plates used may depend on the length of each layer. The vertical plates  609  may be attached to the display housing, integrated with the display housing, or be separate altogether. The width of each plate  609  may be 0.1″-0.2″ larger than the profile, and each plate  609  might be located between two LEDs&#39; openings in the layers. The vertical plates  609  therefore only minimally block air flow and also only minimally affect the visual characteristics of the display, if at all. The length of the plates  609  may depend on the number of layers used in the display panel. The holes in each plate  609  may be cut using a lathe cut CNC machine. Punch or press techniques may alternatively be used. Once each layer is inserted into the vertical plates  609 , the layers are thereby prevented from twisting. 
   Also in any of the embodiments illustrated in  FIGS. 1-3 , an alternative configuration may be used where horizontal receiver  105 ,  205 ,  305  is used for running cabling and installing internal components of the layer housing. In such a configuration, each layer is fixed to the display housing at each layer&#39;s ends and optionally supported using plates  609 . In any embodiment, in order to reduce weight, each layer might be divided into two portions: a head portion using aluminum extruded housing for electronic and electric components; and a tail portion using plastic extrusion for blocking stray light from the back of the sign. The two portions may be joined together by sliding gripping features of one portion inside of retaining slots of the other. The hole in the aluminum extrusion may be used for attaching the sealing caps at the edges of each layer. 
     FIG. 4  illustrates a plurality of layers  101   a ,  101   b ,  101   c , and  101   d  (collectively,  101 ) arranged for use in a display panel housing (not shown), according to an illustrative embodiment of the invention. The plurality of layers, each housing a plurality of lighting elements, form an array of lighting elements that may be selectively turned on and off to form a lighted message on the display panel. The layers are arranged with space between each layer to form pass-through vents  401   a ,  401   b , and  401   c  (collectively,  401 ). Air, wind, rain, sleet, snow, etc can more easily pass through vents  401  than through previously known display panels, while the display panel maintains sufficient contrast for a viewer to view a message displayed on the display panel. 
     FIG. 5  illustrates an alternative plurality of layers  201   a ,  201   b ,  201   c , and  201   d  (collectively,  201 ) arranged for use in a display panel housing (not shown), according to an illustrative embodiment of the invention. The plurality of layers, each housing a plurality of lighting elements, form an array of lighting elements that may be selectively turned on and off to form a lighted message on the display panel. The layers are arranged with space between each layer to form pass-through vents  501   a ,  501   b , and  501   c  (collectively,  501 ). The wing-shaped design, e.g., indicated by section B, reduces wind effects on each layer. Air, wind, rain, sleet, snow, etc can more easily pass through vents  501  than through previously known display panels, while the display panel maintains sufficient contrast for a viewer to view a message displayed on the display panel. Further, the complete environmental encapsulation, e.g., as indicated at Section D, protects the lighting elements from external conditions such as rain, wind, debris, and the like. 
   Each leading edge of each layer housing, or at a minimum a portion of the leading edge covering each lighting element, may be made of a clear or translucent polycarbonate impact resistant cover, e.g., as shown by arrow A, thereby allowing viewers to see each lighting element while providing sufficient protection of each lighting element. The cover may also reduce glare to a viewer to the display panel. As indicated above, each layer housing is preferably made of a dark color or a color that provides contrast, e.g., as shown by arrow C, with lit lighting elements. At a minimum, each layer preferably has the dark or contrasting color at the locations incident to the intended viewing angle of the display panel. In embodiments using a wing or airfoil type design, the repeated airfoil layers may act to counteract effects of lift resulting from the airfoil design. However, the airfoil design may still be unsuitable in areas receiving high winds. In such areas a form factor utilizing countervailing top and bottom slat surfaces, such as are illustrated in  FIGS. 1 ,  2  and  4 , may be used. 
   The dimensions of each layer can vary depending on the size of each lighting element, components inside each layer and their composition, the size of the display panel, and based on other needs of the user of the display panel. Dimensions may also be limited by the pitch of each layer and the value of the required angle to limit stray light when viewed from within an intended viewing angle or range of angles. In one illustrative embodiment of the invention, the width of each layer is approximately two (2) inches. 
     FIG. 6  illustrates a display panel  601  having display housing  603  and a plurality of layers  605 . Wiring and circuitry may be run internal to layers  605  and/or housing  603 . Each layer  605  houses one or more lighting elements  607  that can be selectively turned on and off by a display panel controller (not shown) to create a message or picture for display on the display panel  601 . Each layer  605  is preferably substantially the same as other layers, and utilizes a housing form factor such as is illustrated in  FIGS. 1-3 , or any other form factor as described herein. Portions of each layer may be made of plastic to decrease the overall weight of each display panel. 
   The aerodynamic display panel described herein preserves life and reduces risk by encapsulating each LED in an environmentally secure housing to survive in extreme conditions. The array of lighting elements, arranged in a plurality of separated layers, reduces resistance to wind and water by allowing them to pass through the display panel. According to some embodiments of the invention, the layers may be simultaneously louvered to a desired angle to provide optimum wind resistance. The display panel design described herein also supports effective heat dissipation by encouraging convective air currents to pass over and through the array (similar to a radiator) to dissipate heat. Because the life of an LED is directly related to removal of heat from the LED junction, this also helps preserve the longevity of each LED (or other lighting device) in the display panel. Getting the heat onto the aluminum extrusion very quickly facilitates rapid heat dissipation. 
   The display panel may be scaled up or down accordingly to an appropriate size for the desired use. In addition to use on fixed variable message signs, for example those over highways and on other fixed structures, the display panel may also be adapted to connect to or be permanently attached to a display stand, thereby allowing portability of the display panel to various locations as needed. The wind resistant qualities of the display panel described herein help to offset the often minimal wind resistant strength of portable stands. The stand may be a folding tripod or similar device, and may include one or more anchors for tying down or hammering into a surface on which the stand is placed. Similarly, a portable battery may be included with the display stand to negate the need for a gas-powered or other electrical generator. 
   The present invention includes any novel feature or combination of features disclosed herein either explicitly or any generalization thereof. While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques. Thus, the spirit and scope of the invention should be construed broadly as set forth herein.