Patent Publication Number: US-7716861-B2

Title: Outdoor display sign

Description:
RELATED APPLICATIONS 
   None 
   FIELD OF THE INVENTION 
   The present invention relates generally to the field of signs and more particularly to an outdoor display sign. 
   BACKGROUND OF THE INVENTION 
   Outdoor variable message signs are used to provide information to motorists. One example of these signs are the variable message signs used by highway departments to tell motorists, what lanes are open and short messages such as accident ahead. It is the goal of highway departments to provide motorist with more information on the state of the highway ahead. Variable message signs require controllers, drivers, and a number of environmental control systems. These environmental control systems include filters that have to be replaced, fans to blow air through the sign and in some cases air conditioners. This increases the cost of variable message signs and limits the number of places that these signs are utilized. 
   Thus there exists a need for a simpler, less expensive outdoor variable message sign. 
   SUMMARY OF INVENTION 
   An outdoor display sign that overcomes these and other problems has a display enclosure. The display enclosure has a number shades that reduce the solar loading on the display enclosure. The outdoor display sign has shades covering the top, back, sides and parts of the front of the sign. The shades may be offset from the display enclosure to allow natural airflow between the shade and the display enclosure. In one embodiment, the display enclosure is completely sealed and does not have any environmental control equipment. This is because the shades provide adequate shading of the sun so that no environmental control equipment is required. Occasionally, the sealed display enclosure has a detached controller and/or power supplies. In one embodiment, the display enclosures are modular and may be used to build a larger sign out of a number of one line modules. The sign may have a mask that provides contrast enhancement for the display and provides additional protection from solar loading when the sun is low in the sky. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective drawing of an outdoor display sign in use on a highway in accordance with one embodiment of the invention; 
       FIG. 2  is a side view of an outdoor display sign in accordance with one embodiment of the invention; 
       FIG. 3  is a cross section of an outdoor display sign in accordance with one embodiment of the invention; 
       FIG. 4  is a perspective view of a display enclosure in accordance with one embodiment of the invention; 
       FIG. 5  is a perspective view of the modular nature of a display enclosure in accordance with one embodiment of the invention; 
       FIG. 6  is a cross section of an outdoor display sign in accordance with one embodiment of the invention; and 
       FIG. 7  is a cross section of a display enclosure showing a mask in accordance with one embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE DRAWINGS 
   The present invention is directed to an outdoor variable message display sign that is inexpensive to build and maintain. A key to building an inexpensive variable message sign was to eliminate the need for an active cooling system. These outdoor variable message signs use LEDs (Light Emitting Diodes) or other electrical/electronic light sources. When these light sources and their associated electronics get too hot it reduces their lifetime. The outdoor variable message display sign described herein keeps the electronics cool using a passive system of shades. The electronics and lights are placed in a display enclosure. The display enclosure has shades that block the light from hitting the top, back, sides and front of the display enclosure. The shade facing north may be eliminated because the sun will not shine on the north side of the sign in the northern hemisphere. Of course the opposite is true in the southern hemisphere. Since the sun&#39;s solar loading is the biggest factor effecting the internal temperature of a sign, using the shades allows a display to have no active cooling or at least significantly reduces the cooling system requirements. The structure to hold the shades may be designed so that air may freely travel between the display enclosure and the shades. This allows natural breezes to cool the display enclosure and associated electronics and allows for natural convention to pull cool air past the display enclosure. As a result, of this passive cooling system the outdoor display sign is easier and less expensive to build than actively cooled signs. In addition, the sign may have a mask that provides contrast enhancement for the display and provides additional protection from solar loading when the sun is low in the sky. 
     FIG. 1  is a perspective drawing of an outdoor display sign  10  in use on a highway in accordance with one embodiment of the invention. The sign  10  in this case is mounted below a standard static highway sign  12 . The outdoor display sign  10  has a controller  14  which may be pole mounted or may be on the ground. The controller  14  is in communication with the sign  10  and directs the sign to display various messages  16 ,  18 ,  20 . In this case the sign  10  is a one line sign and is just displaying an “X”  16  for a closed lane and an arrow  18  &amp;  20  for an open lane. 
     FIG. 2  is a side view of an outdoor display sign  30  in accordance with one embodiment of the invention. It is important to note that the invention is directed to electronic signs where cooling is an issue due to solar loading. This view shows that the sign enclosure (shown in  FIG. 3 ) is shaded by a top shade  32 , back shade  34 , side shade  36  and front shade  38 . The shades  32 ,  34 ,  36 ,  38  form a shade system that block direct sunlight from impinging on the display enclosure except on the face of the display enclosure when the sun is low in the sky. “Low in the sky” can be defined as only 25 degrees above the horizon or lower. 
     FIG. 3  is a cross section of an outdoor display sign  30  in accordance with one embodiment of the invention. The sign  30  contains a display enclosure  40 . The display enclosure  40  holds the electronic/electric light sources and associated drive electronics. In one embodiment, the display enclosure  40  is completely sealed. This means that essentially no air or water enters or leaves the display enclosure  40 . In addition, it means that the light sources are enclosed in the display enclosure. In one embodiment, the display enclosure  40  has a transparent glazing in front of the light sources. A mask (see  FIG. 7 ) may be used to further reduce the solar loading when the sun is low in the sky and impinging on the front of the sign. The display enclosure  40  is mounted to a back mounting plate  34 , which acts as a back shade. The support members  42  are shown as dashed lines. The support members  42  do not significantly impede the airflow between the back of the display enclosure  32  and the mounting plate  34 . A top shade  32  is mounted to the mounting plate  34 . The top shade  32  is offset from the top of the display enclosure  40  and keeps the sunlight from directly hitting the top of the display enclosure  40 . A display shade  38  is offset from the display enclosure  40  and is coupled to the mounting plate  34  by supports  42 . Again the supports do not extend the length of the display enclosure  40  and therefore do not impede the airflow between the shades  32 ,  34 ,  38  and display enclosure  40  or between the display enclosure  40  and the mounting plate  34 . Note that the display shade  38  is sloping instead of horizontal to shed snow. In environments that do not have snow, the front shade  38  may be horizontal instead of sloping. 
     FIG. 4  is a perspective view of a display enclosure  40  in accordance with one embodiment of the invention. In this case the display enclosure  40  is a single line display. Commonly, the display enclosure  40  has a plurality of LEDs (Light Emitting Diodes) that are used to form the display “Accident Ahead”  44 . Note that the display  44  is considered the front of the display enclosure. In one embodiment, the display enclosure  40  is sealed. This means that the display enclosure  40  does not allow exchange of water, dirt or air between the interior of the enclosure and the exterior of the enclosure. 
     FIG. 5  is a perspective view of the modular nature of a display enclosure in accordance with one embodiment of the invention. A pair of display enclosures  50  &amp;  52  are placed next to each other to form a coherent single display  54 . Each of the display enclosures  50  &amp;  52  are controlled by a single controller to form the display “ICE ON ROAD.” Note that the display enclosure can also be placed side by side to form a long horizontal sign. 
     FIG. 6  is a side view of an outdoor display sign  60  in accordance with one embodiment of the invention. This sign  60  is a multi-line display. The display enclosure  62  has four lines  64 ,  66 ,  68 ,  70  of display. The sign  60  has a top shade  72  and a number of display shades  74 ,  76 ,  78 ,  80  and has a back shade  82 . Note that the display sign  60  may also have side shades similar to that shown in  FIG. 2 . The display shades  76 ,  78 ,  80  are positioned between the display lines  64 ,  66 ,  68 ,  70  of the display. The shades  72 ,  74 ,  76 ,  78 ,  80  are offset from the display enclosure  62  and held in place by structural supports. This shading reduces or eliminates the need for active cooling systems. 
   Computer simulations have shown that the single line variable message display sign similar to the one in  FIGS. 2 &amp; 3  will actually have lower temperatures for the control electronics in most cases than actively cooled signs. 
     FIG. 7  is a cross section of a display enclosure  90  showing a mask  92  in accordance with one embodiment of the invention. The mask  92  has a number of holes  94 ,  96 ,  98 ,  100 ,  102 ,  104 ,  106  that are generally circular. The front  108  of the mask  92  is a mat black which enhances the contrast ratio of the sign  90 . The mask  92  is held to a glazing  110  by insulating foam adhesive strips  112 . The adhesive strips  112  hold the mask  92  offset from the glazing  110 . As a result, air can flow between the holes  94 ,  96 ,  98 ,  100  and  102 ,  104 ,  106 . The air flow between the holes helps to keep the sign enclosure  90  cool. In addition, the offset prevents thermal conduction from the mask to the glazing  110 . The holes  94 ,  96 ,  98 ,  100 ,  102 ,  104 ,  106  are aligned with the display elements  114 . Thus, there has been described an outdoor variable message sign that provides maximum protection from solar loading. As a result, the sign enclosure generally does not require active cooling systems. 
   While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alterations, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alterations, modifications, and variations in the appended claims.