Abstract:
An LED display module having features for improvement over prior art devices by providing novel features for improved LED visibility, improved weather and climatological sealing, improved electromagnetic interference (EMI) suppression, improved heat dissipation, and improved airflow.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This patent application is related to patent application Ser. No. 11/271,404 filed Nov. 10, 2005 entitled “Stackable Electronic Sign System And Mounting Structures Therefor,” which is pending. This patent application is also related to patent application Ser. No. 10/688,304 entitled “Electronic Display Module Having a Four-Point Latching System for Incorporation into an Electronic Sign and Process”, filed on Oct. 17, 2003, pending. Patent application Ser. No. 10/688,304 claims priority from the earlier filed U.S. Provisional Application No. 60/647,268 filed Jan. 25, 2005, entitled “Electronic Sign”. The prior applications are hereby incorporated into this application by reference as if fully set forth herein. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention is for an LED display module and, more particularly, an LED display module preferably incorporated into use with a connector framework such as featured in patent application Ser. No. 11/271,404 filed Nov. 10, 2005 entitled “Stackable Electronic Sign System And Mounting Structures Therefor,” by the inventor(s). 
     Description of the Prior Art 
     Small LED Package 
     Prior art LED display modules often incorporated an arrangement of a plurality of different colored LEDs, such as RGB colors, incorporated into a single structure where such an arrangement is known as an LED package. Multiple LED packages, such as four LED packages, were then combined in a spaced square arrangement and viewed through a single louver viewing port being slightly larger than the arrangement of the four LED packages. In the alternative, a smaller LED package could be observed through a single and smaller louver viewing port. In either case, a large visible white area of the LED package sides surrounding the LED packages adversely affects the contrast of the display, especially when viewed from the side and viewability was deemed unacceptable due to the presence of a “halo” effect resulting in viewing and module uniformity inconsistency. The present invention provides a smaller LED package viewable through reduced size single louver view ports and through co-located individual overmold cavity view ports, wherein the visible white area around the edge of an LED is significantly reduced by one-to-one correlation of a single view port to a single overmold cavity view port. Contrast and viewability is enhanced by the use of a support grid having a dark color, such as black, for purposes of example and illustration. 
     Weather Seal 
     The perimeter surface of prior art LED display modules often incorporated a sealant where the module frame came in contact with the louver panel. The sealant attempted to fill in the post-assembly gap left between the frame and the louver panel. After the module had been cycled through expansion and contraction cycles from cold and warm temperatures, the sealant cracked, thereby no longer properly sealing the LED display module. Additionally, the louver panel was designed to fit tightly against the coated surface of the LED printed circuit board, but this arrangement was not watertight and water flowed into the area between the louver panel and the front surface of the LED circuit board where it pooled, causing corrosion of the coating on the LED circuit board and subsequent premature component failure. Prior art louver panels were attached to the module by Mattel pins that extended perpendicularly through the LED printed circuit board and through other components of the module. A small rubber gasket was placed on each Mattel pin near its base to plug the gap between the Mattel pin and the respective hole in the LED printed circuit board but this technique did not reliably serve its purpose since water entered through each respective hole. 
     The present invention overcomes the inadequacies of the prior art by the use of a panel which is overmolded to and in close association with a louver panel. The side panels of the louver panel form a peripheral lip which wraps around and mostly contains the LED printed circuit board and other closely related components to snappingly engage a peripheral lip of a rearwardly located frame. The overmold panel engages and seals to the front surface of the LED printed circuit board in close proximity to the sides of the LED packages. 
     Heat Dissipation 
     The problem with some prior art electronic display modules is that excess heat is produced by the number of LEDs and, therefore, the excess heat is not removed effectively. The heat produced by LED display modules combined with the ambient temperature can produce an unsafe and uneven operating temperature for the LED display modules. In addition, outdoor use of the LED display modules results in even more heat energy being involved due to solar radiation along with extra heat produced by operating the LEDs at an increased intensity to provide proper display brightness for outdoor conditions. Previously, few methods for evenly or effectively removing heat from LED display modules and heat removal in general was accomplished by having as much open area, as possible, at the rear of an LED display module, hoping in most cases for heat dissipation by natural convection. Another ventilation method of cooling electronic display systems is the use of an air conditioning system which is expensive, takes extra installation time, requires more electrical energy to operate, and is noisy. Another ventilation method of cooling electronic display systems is using axial driven fans which are not compact, which are noisy, which produce low pressure, which have a low CFM rating, and which require a large opening. Other ventilation systems, regardless of the type of cooling source, do not have structure on the inside of the panel to force the air over a greater surface area of the panel. 
     The present invention provides heat dissipation structure which evenly cools the LED display module by the use of a thermal conductive pad, a heat distribution plate and heat sinks associatively incorporated to draw and expel heat therefrom. The present invention provides for ventilation by the use of an internally located centrifugal air pump to forcibly extract heat off the non-viewed side of the LED display assemblies including the heat sinks and associated components in an even and effective manner. 
     Electromagnetic Interference 
     Electronic display modules can emit a significant amount of electromagnetic interference (EMI), whereby significant amounts of electromagnetic radiation transmitted from such electronic devices may cause problems such as interference with surrounding electrical devices, such as radios, televisions, cell phones, electronic medical devices and the like, as well as possibly being in violation of FCC regulations for electromagnetic radiations. The present invention provides structure to contain, reduce and suppress any internally generated EMI. One structure is in the form of an electrically grounded rear cover made of a type of plastic having EMI inhibiting qualities which contains, reduces and suppresses EMI. The electrically conductive surfaces within the rear cover are connected to earth ground via a power connection to the LED display assemblies. Other structures, such as, but not limited to, a frame and a louver panel are also constructed of plastic having EMI inhibiting qualities. In the alternative or in addition thereto, the rear support panel and other such structures can be protected with an EMI inhibiting paint or the rear cover and other referenced structures can be expensively fashioned of conductive metal to contain, reduce and suppress any internally generated EMI. However, metal is much heavier than plastic making installation and transportation more difficult. Unlike plastic, metals cannot be as easily formed or molded to various shapes typically beyond block designs and simple radius designs, thereby making the use of components comprising an electronic LED display module having plastic EMI inhibiting qualities a preferred structure. 
     These above methods will work alone to prevent electromagnetic noise from escaping the electronic sign displays if the rear support panel has no openings or gaps sizeable enough to let a significant amount of electromagnetic noise escape. A problem arises because many of these panels have openings used for ventilation intake and the size of the openings is large enough for significant electromagnetic noise to escape. The present invention provides for EMI protection at any such openings where grounded mesh-like metal screen or EMI material protective screens are placed at the air intake enclosure and centrifugal air pump enclosure to block electromagnetic noise from escaping. In the alternative, use of gaskets having anti-EMI qualities can be used at multiple component contact locations in order to prevent electromagnetic noise from escaping through these areas. 
     SUMMARY OF THE INVENTION 
     The general purpose of the present invention is to provide an LED display module having features for improvement over prior art devices by offering novel features for improved visibility of the LEDs, improved weather and climatological sealing, improved EMI (electromagnetic interference) suppression, improved heat dissipation and improved airflow. The LED display module of the present invention includes multiple LED display assemblies having a rear cover secured to the back side thereof. 
     The LED display module features a plastic louver panel preferably of a dark color having a layer of overmold material such as a thermoplastic elastomer for weather sealing against an LED printed circuit board in close association about individual LED packages. Louver panel view ports having a continuous angled surface and a continuous sub-lip are located along and about a support grid of the louver panel. The visible white area around an LED is significantly reduced by the use of the individual sub-lips, thereby increasing the contrast and improving viewability of the LED packages. A peripheral lip of the louver panel having molded latches wraps around the edges of the LED printed circuit boards and other components and snaps over, about and onto the peripheral lip of a frame having molded-in catches, and further sealed by application of a suitable sealing material at the louver panel frame splice seam. The frame, which is preferably made of plastic having EMI protective material, encases, houses and surrounds the LED printed circuit board, as well as surrounding a thermal conductive pad and a heat distribution plate. The frame has an open front, four solid perimeter sides, a peripheral lip and a back that has a structure to allow for rigidity while having openings allowing electronics from the LED printed circuit board and heat sinks to pass through. 
     The plastic louver panel with the overmold panel is substantially a unitary structure, but shown herein as separate structures for the purpose of clarity. The overmold panel provides a plurality of single overmold cavity viewing ports. The planar portion of the overmold panel seals against the LED printed circuit board. The overmold cavity viewing ports align in close proximity to and about individual LED packages. 
     A dedicated heat dissipation structure evenly cools the electronic LED display module. Three static components are used to draw and expel heat from the modules. First, a thermal conductive pad that is not electrically conductive is placed directly on the rear surface of the LED printed circuit board. Second, a heat distribution plate is preferably made of electrically conductive aluminum and is placed over the thermal conductive pad. The combination of the thermal conductive pad and heat distribution plate help dissipate heat from the LED printed circuit board and evenly distribute the heat across the whole volume of the LED display module. Thirdly, heat sinks are secured on the rear of the heat distribution plate to increase the surface area and expedite heat dissipation. 
     The invention uses a centrifugal air pump to provide cooling air in and out of the LED display module. The air is pulled through and along the interior of the rear cover on a given path to flow over as much surface area of the back of the upper and lower LED display assemblies and along and about the components of the rear cover of the LED display module as possible. The air is forced in a circuitous path because panels in the panel cover extend preferably perpendicularly and forwardly from the interior surface of the rear cover to the rear surface of the rear cover, thus preventing the cooling air from being drawn in through the air intake enclosure inlet and then directly to the centrifugal air pump intake without properly entraining and removing heat residing along the entire interior of the LED display module. 
     The rear cover includes integral portions consisting of a rear support panel, a rear enclosure panel, an air intake enclosure, and a centrifugal air pump enclosure which are closely associated with and in close proximity to the rear of the LED display assemblies. The rear cover provides EMI protection in one of two main ways. Preferably, the plastic comprising the rear cover can be made of an EMI protective material or, in the alternative, the plastic rear cover can be painted with EMI protective paint. EMI protection may also be provided in the form of screens located in the centrifugal air pump enclosure and in the air intake enclosure. Alternatively, gaskets which can have EMI protection qualities can also be incorporated at multiple locations where the structures mate. 
     According to one or more embodiments of the present invention, there is provided an LED display module including a louver panel with an overmold panel of thermoplastic elastomer material, LED display assemblies, a frame containing EMI protective material which accommodates and is used for mounting of an LED printed circuit board, a heat distribution plate, a heat distribution plate and a thermal conductive pad, a plurality of heat sinks secured to the back of the heat distribution plate, multiple sealing gaskets having EMI protective material, a one-piece rear cover containing EMI protective material including a support panel, an enclosure panel, an air intake enclosure, a centrifugal air pump enclosure, a centrifugal air pump, an LED display module latching system, as well as numerous other components. 
     One significant aspect and feature of the present invention is an LED display module for use in indoor and outdoor electronic displays. 
     Another significant aspect and feature of the present invention is the use of a louver panel of a dark contrasting color to increase the contrast and viewability of LED packages in an LED display assembly. 
     Another significant aspect and feature of the present invention is the use of a continuous sub-lip included in louver panel view ports to mask the edges of white colored LED packages from view, thereby increasing the contrast and viewability of LED packages in an LED display assembly. 
     One significant aspect and feature of the present invention is the use of a single LED package within a single louver panel view port to create a perceived doubling effect of the contrast by viewers by greatly reducing the white space about an LED package. 
     Still another significant aspect and feature of the present invention is the use of overmold panel material which is soft and flexible which can be aggressively molded in very close proximity to an LED package without incurring LED package damage. 
     Yet another significant aspect and feature of the present invention is the use of an overmold panel to effect a seal between the hard plastic louver panel and an LED printed circuit board, as well as closely about LED packages. 
     Yet another significant aspect and feature of the present invention is a louver panel designed to allow for 140° viewing in all directions. 
     Yet another significant aspect and feature of the present invention is a louver panel provided to protect the LED packages from abuse. 
     Yet another significant aspect and feature of the present invention is the use of an overmold panel having a plurality of overmold cavity view ports which are in close proximity to the plurality of LED packages. 
     Yet another significant aspect and feature of the present invention is the use of co-located louver panel view ports and overmold cavity view ports. 
     Yet another significant aspect and feature of the present invention is the use of overmold cavity view ports for protection of LED packages. 
     A still further significant aspect and feature of the present invention is a louver panel having intersecting angled surfaces on a support grid to provide rigidity and LED package protection. 
     Yet another significant aspect and feature of the present invention is the use of a louver panel having a support grid which acts to decrease visible module seams. 
     Another significant aspect and feature of the present invention is a louver panel having side, top and bottom panels forming a peripheral lip which extends over and about the frame and which snappingly engages the peripheral lip of the frame, as well as to positionally fix and capture the LED printed circuit board, the thermal conductive pad and the heat dissipation plate. 
     Another significant aspect and feature of the present invention is to provide even and effective cooling of electronic LED display modules which can be run in higher ambient temperatures without incurring heat related problems. 
     Another significant aspect and feature of the present invention is to provide a more efficient way of removing heat from components on the LED printed circuit board. 
     Another significant aspect and feature of the present invention is the use of a thermal conductive pad, a heat distribution plate and a plurality of heat sinks combined and secured to the back of LED printed circuit boards to draw heat off the back of LED printed circuit boards and to remove heat from components on the LED printed circuit board and evenly dissipate such heat across the entire volume of the LED display module. 
     Another significant aspect and feature of the present invention is the use of an internally located centrifugal air pump to provide fresh cooling air to the LED display module to forcibly draw heat from the combined thermal conductive pad, heat distribution plate and plurality of heat sinks and forcibly exhaust such heat externally. 
     Another significant aspect and feature of the present invention is the reduction in operating noise compared to the use of an air conditioning system with an LED display module. 
     Another significant aspect and feature of the present invention is the compact, low profile size ventilation system. 
     Another significant aspect and feature of the present invention is to promote airflow to take place over as much surface area of the LED display module as possible. 
     Another significant aspect and feature of the present invention is the incorporation of sealing and other features to eliminate EMI (electromagnetic interference). 
     Another significant aspect and feature of the present invention is the use of EMI paint over a rear cover, the frame or other components or molding EMI material into a rear cover, the frame or other components. 
     Another significant aspect and feature of the present invention is an LED electronic display module having EMI protection which is lighter than previous EMI protected LED electronic display modules. 
     Another significant aspect and feature of the present invention is the use of screens, or in the alternative, the use of screens having EMI protective material at an air intake enclosure and at a centrifugal air pump enclosure. 
     Another significant aspect and feature of the present invention is an LED display module which can easily include a variety of shapes that increases aesthetics, increases ease of handling, and that can have verbiage, directions, and logos easily inscribed on the surface thereof. 
     Having thus briefly described embodiments of the present invention and having mentioned some significant aspects and features of the present invention, it is the principal object of the present invention to provide an LED display module. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects of the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein: 
         FIG. 1  is a front view of an LED display module, the present invention; 
         FIG. 2  is a rear view of the LED display module; 
         FIG. 3  is a semi-exploded rear view of the LED display module; 
         FIG. 4  is an exploded front view of the upper LED display assembly; 
         FIG. 5  is an exploded rear view of the upper LED display assembly; 
         FIG. 6  is a rear view of a louver panel distanced from a frame; 
         FIG. 7  is a front view of the louver panel distanced from the frame; 
         FIG. 8  is a front view of a rear cover; 
         FIG. 9  is an exploded side view of the upper LED display assembly showing the alignment of the components forming the LED display assembly; 
         FIG. 10  is an exploded partial front view of some components of the LED display assembly comprising the upper left corner of the louver panel showing a partial front view of components located in close relationship to the louver panel; 
         FIG. 11  is an assembled partial view and partially exploded view incorporating many of the components of  FIG. 10 ; 
         FIG. 12  is an exploded and partial view showing some of the components closely associated with the upper left corner of the LED display assembly and in close relationship to the louver panel; 
         FIG. 13  is an assembled view of the components of  FIG. 12 ; 
         FIG. 14  is a cross section view of the upper LED display module along line  14 - 14  of  FIG. 3  showing the close and intimate relationship of the heat sinks to the heat distribution plate, the thermal conductive pad, and the LED printed circuit board; 
         FIG. 15  is a rear view of the rear cover showing the lower structures of the air intake enclosure and the centrifugal air pump enclosure; 
         FIG. 16  is an exploded front view of the rear cover showing the filter assembly, the centrifugal air pump, the framed filter and associated components distanced from the rear cover; and, 
         FIG. 17  shows the rear cover of the LED display module showing airflow along the inner regions and components thereof. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a front view of an LED (light emitting diode) display module  10 , the present invention, and  FIG. 2  is a rear view of the LED display module  10 . Fully or partially visible components as shown in  FIG. 1  and/or  FIG. 2  include an upper LED display assembly  12 , a lower LED display assembly  14 , and a configured one-piece rear cover  16  made preferably from polycarbonate combined with EMI protective material. The rear cover  16  includes a top panel  18 , opposed side panels  20  and  22 , a bottom panel  24 , a support panel  26  extending between the rear edges of the top panel  18 , the opposed side panels  20  and  22 , and the bottom panel  24 , an enclosure panel  28  extending from the support panel  26 , an air intake enclosure  30  extending from the support panel  26 , and a centrifugal air pump enclosure  32  extending from the support panel  26  for housing an internally located centrifugal air pump  34 . Also located at the rear of the support panel  26  is an LED display module latching system  36  transversely located upon the central portion of the support panel  26  incorporated to removably attach the other components of the LED display module  10  to a connector framework, such as described in patent application Ser. No. 11/271,404 filed Nov. 10, 2005, entitled “Stackable Electronic Sign System And Mounting Structures Therefor,” which is pending, as well as being closely related to patent application Ser. No. 10/688,304 entitled “Electronic Display Module Having a Four-Point Latching System for Incorporation into an Electronic Sign and Process” filed Oct. 17, 2003. The LED display module latching system  36  includes a framework  38  and framework mounted components including, but not limited to, a centrally located actuator mechanism  40  which is accessible from the front or the back, opposed actuator arms  42   a  and  42   b  extending in opposite directions from and operated in opposing directions from and by the actuator mechanism  40 , and latch housings  44   a  and  44   b  at the outer ends of the framework  38  for housing pivotable latches  46   a  and  46   b  which are pivotally operated by the outer ends of the actuator arms  42   a  and  42   b , respectively. The pivotable latches  46   a  and  46   b  engage catches located at the forward edges of connector frameworks or other catch devices as referred to in the previously referenced patent applications. A handle  48  is also included at the lower portion of the enclosure panel  28 . A heat sink  50  extends through the lower portion of the support panel  26  between the air intake enclosure  30  and the centrifugal air pump enclosure  32  with the aid of a gasket  52  ( FIG. 3 ) to intimately contact and to draw heat from an electronics module  54  shown in  FIG. 8 . A plurality of alignment posts  56  extend rearwardly from the support panel  26  for alignment with connector frameworks. 
       FIG. 3  is a semi-exploded rear view of the LED display module  10  showing the upper LED display assembly  12  which includes an upper weather seal  58  and a larger upper weather seal  60  and the lower LED display assembly  14  which includes a lower weather seal  62  and a larger lower weather seal  64 , all of which components are shown separated and distanced from the rear cover  16 . The upper weather seals  58  and  60  and the lower weather seals  62  and  64  seal against the upper LED display assembly  12  and the lower LED display assembly  14 , respectively, in a double sealing arrangement involving the effecting of multiple seals with the rear cover  16 . A connector plate  65  is secured to the frame  80  of the upper LED display assembly  12  and to the frame  80  of the lower LED display assembly  14 , thereby connecting the upper LED display assembly  12  to the lower LED display assembly  14 . The heat sink  50  and the weather seal  52  are shown in distanced alignment to an access opening  66  in the support panel  26  of the rear cover  16 . 
       FIG. 4  is an exploded front view of the upper LED display assembly  12 , and  FIG. 5  is an exploded rear view of the upper LED display assembly  12 . The lower LED display assembly  14  is similar to the upper LED display assembly  12  and is not described separately for the purpose of brevity. The major components of the upper LED display assembly  12  include a louver panel  68  preferably of a dark contrasting color, an overmold panel  70  which is transparent or which can be translucent and which is later molded to but which is shown separately from the louver panel  68 , an LED printed circuit board  72  (PCB) containing LED packages and other electronic components and associated features forming a unitary structure, as described later in detail, a thermal conductive pad  74 , a heat distribution plate  76  preferably of aluminum or other highly heat conductive material which preferably is electrically conductive and grounded as an anti-EMI feature, a weather seal  78 , a configured frame  80 , a previously shown weather seal  58 , a previously shown weather seal  60 , and a plurality of heat sinks  82   a - 82   n . Portions of the LED packages mounted on the printed circuit board  72  are shown at or near one vertical edge of the printed circuited board  72  for purposes of brevity and clarity. The overmold panel  70 , the LED printed circuit board  72 , the thermal conductive pad  74 , the heat distribution plate  76  and the weather seal  78  are intimately and closely assembled and forcibly held and contained within forward facing cavity  142  ( FIG. 7 ) of the configured frame  80  by the louver panel  68 , the assembly of which is shown in  FIG. 3 , and which is also shown in cross section in  FIG. 13 . The previously described weather seals  58  and  60  ( FIG. 3 ) interface between the rear portion of the frame  80  in a double sealing arrangement with structure of the rear cover  16 , as do weather seals  62  and  64  with respect to the lower LED display assembly  14 . 
       FIG. 6  is a rear view of the louver panel  68 , shown in cutaway view, distanced from the frame  80  which is also shown as a rear view. The louver panel  68  includes a top panel  84 , a side panel  86 , a side panel  88 , and a bottom panel  90 , as well as other components as described herein. The interior surfaces of the top panel  84 , the side panel  86 , the side panel  88 , and the bottom panel  90  include a plurality of spaced latches  92 , each having one or more sloped surfaces distributed along and thereabout, whereby each of the latches  92  is raised above and extends inwardly from the respective interior surface. A support grid  93  is formed of a plurality of vertical aligned supports  94   a - 94   n  extending between the top panel  84  and the bottom panel  90  which mutually and multiply intersect a plurality of horizontally aligned supports  96   a - 96   n  extending between the side panel  86  and the side panel  88  substantially delineating and supporting a plurality of louver panel view ports  100   a - 100   n  extending therethrough and being arranged in grid fashion. The louver panel  68  can be formed of any suitable plastic or other material and can be coated preferably with a low reflection paint in order to inhibit a shiny or reflective quality and to improve contrast. In the alternative, the louver panel can be formed of surfaces which are nonreflective in nature. A feature, such as stippling, etching, or the like, can be used in order to reduce a reflective glare. LED packages  170   a - 170   n  ( FIG. 10 ) are aligned in close relationship to the rear of the louver panel view ports  100   a - 100   n , whereby such LED packages are visible through features of the transparent overmold panel  70  ( FIG. 11 ) which is aligned with and intimately engages the support grid  93  surrounding the louver panel view ports  100   a - 100   n , as described later in detail. The front of the one-piece louver panel  68 , as shown in  FIGS. 10 and 11 , includes the front portion of the support grid  93  which collectively surrounds the front of each of the surrounding louver panel view ports  100   a - 100   n , as well as overmold cavity view ports  174   a - 74   n  of the overmold panel  70  which extend through the louver panel view ports  100   a - 100   n . The collective front surface portions of the support grid  93  surrounding each of the surrounding louver panel view ports  100   a - 100   n  are angled to form a plurality of louvers for the purpose of protection of LED packages and for shading of the LED packages, as described later in detail. A plurality of engagement pins  102   a - 102   n  are located at and extend rearwardly from various locations on the support grid  93 . The engagement pins  102   a - 102   n  align and extend through the overmold panel  70 , the LED printed circuit board  72  and some closely associated components thereof, the thermal conductive pad  74 , the heat distribution plate  76 , and also align with, extend into and engage pin receiver posts  140   a - 140   n  ( FIG. 7 ) located in the front facing portion of the frame  80 . Opposed semi-circular notches  103  and  105  are included in the top panel  84  and the bottom panel  90 , respectively, for alternate operation of the LED display module latching system  36  ( FIG. 2 ) through adjacent stacked upper and lower LED display assemblies  12  and  14 , respectively, as applicable. 
     As also shown in  FIG. 7 , the frame  80  includes a top panel  104 , a side panel  106 , a side panel  108 , and a bottom panel  110 , as well as other components as described herein. A continuous peripheral lip  112  extends rearwardly from the top panel  104 , the side panel  106 , the side panel  108 , and the bottom panel  110 , and includes a plurality of catches  114  (also shown in  FIG. 9 ) distributed along and about the outer surfaces of the peripheral lip  112  where each catch  114  is in the form of an inwardly extending cavity having one or more sloped surfaces. Additionally and collectively, the top panel  104 , the side panel  106 , the side panel  108 , and bottom panel  110  of the frame  80  include a forwardly extending peripheral lip  115  for mating with a segmented peripheral outer lip  148  ( FIGS. 8 ,  12  and  13 ) of the rear cover  16 . A central panel  116  ( FIGS. 7 and 14 ) extends between the top panel  104 , the side panel  106 , the side panel  108 , and the bottom panel  110 , and is interrupted by a plurality of openings  118   a - 118   n  through which components extend or through which access cable connections and the like are available. Opposed semi-circular notches  120  and  122  ( FIG. 7 ) are included in the top panel  104  and the bottom panel  110 , respectively, for alternate operation of the LED display module latching system  36  ( FIGS. 2 ,  3  and  15 ) through adjacent stacked upper and lower LED display assemblies  12  and  14 , respectively, as applicable. A plurality of pins  124   a - 124   n  ( FIGS. 6 and 14 ) extend rearwardly from the central panel  116  some of which can be accommodated by a connector plate  65 , shown in  FIG. 3 . A continuous weather seal channel  126  ( FIGS. 12 ,  13  and  14 ) is located near the periphery of the central panel  116  and just inboard of the top panel  104 , the side panel  106 , the side panel  108 , and the bottom panel  110  for sealed accommodation of the weather seal  60  between the frame  80  and the rear cover  16 . A plurality of recessed threaded inserts  128   a - 128   n  ( FIG. 7 ) are suitably secured along and about the periphery of the central panel  116  ( FIG. 7 ) to receive fasteners, preferably screws, which are incorporated in cooperation with fastener housings  130   a - 130   n  or  132   a - 132   n  located in the rear cover  16  ( FIG. 8 ) to secure the rear cover  16  and components located on the rear cover  16  to the frame  80  of the upper LED display assembly  12  and to the frame  80  of the lower LED display assembly  14 . The upper LED display assembly  12  and the lower LED display assembly  14  are interchangeable. 
       FIG. 7  is a front view of the louver panel  68  distanced from the frame  80  also shown as a front view. Shown in general in the louver panel  68  is the location of the view ports  100   a - 100   n  on the front portion thereof. Structure of the frame  80  is also shown including a support grid  134  formed by a plurality of vertically aligned supports  136   a - 136   n  extending between the top panel  104  and the bottom panel  110  and along various portions of the central panel  116 , and a plurality of horizontally aligned supports  138   a - 138   n  extending between the side panel  106  and the side panel  108  and along various portions of the central panel  116  which supports mutually intersect and which are in close association with the plurality of the various shaped openings  118   a - 118   n . The plurality of forwardly facing pin receiver posts  140   a - 140   n  are located at many of the intersections of the vertically aligned supports  136   a - 136   n  and the horizontally aligned supports  138   a - 138   n  to accommodate and frictionally engage the engagement pins  102   a - 102   n  ( FIG. 6 ) of the louver panel  68 . The expansive cavity  142  accommodates the closely associated overmold panel  70 , the LED printed circuit board  72 , the thermal conductive pad  74 , the heat distribution plate  76 , and the weather seal  78 , and is bounded in general by the peripheral lip  112 , by the forward facing edges of the support grid  134 , and by the forward facing portions of the pin receiver posts  140   a - 140   n . The louver panel  68 , including the closely associated overmold panel  70 , is incorporated to contain the LED printed circuit board  72 , the thermal conductive pad  74 , the heat distribution plate  76 , and the weather seal  78  within the cavity  142 , whereby the engagement pins  102   a - 102   n  of the louver panel  68  extend through the overmold panel  70 , the LED printed circuit board  72 , the thermal conductive pad  74 , and the heat distribution plate  76  to frictionally engage the receiver posts  140   a - 140   n  of the frame  80 . Simultaneously, the top panel  84 , the side panels  86  and  88 , and the bottom panel  90  of the louver panel  68 , which form the peripheral lip  91 , closely engage over and about and are brought into intimate contact with the peripheral lip  112  of the frame  80  during which time the latches  92  of louver panel  68  snappingly engage the catches  114  of the frame  80  to complete yet another method of fastening, in addition to the first method of fastening involving the engagement of engagement pins  102   a - 102   n  of the louver panel  68  within the pin receiver posts  140   a - 140   n  of the frame  80 . The described mating of the louver panel  68  with the frame  80  with the addition of a suitable bead of weatherproof sealant or adhesive  184  about the already tightly configured joinment, as shown in  FIG. 13 , offers weatherproofing between the louver panel  68  and the frame  80 , thereby protecting the components enclosed therein. Weatherproofing between the louver panel  68  and the LED printed circuit board  72  and the closely associated thermal conductive pad  74  and the heat distribution plate  76  is provided by the overmold panel  70 , as described later in detail. 
       FIG. 8  is a front view of the rear cover  16 . The pluralities of fastener housings  130   a - 130   n  and  132   a - 132   n  are shown extending forwardly from the support panel  26 . A continuous inner lip  144  extends forwardly from the support panel  26  in a parallel and spaced relationship with the upper portion of the side panel  20 , with the top panel  18 , and with the upper portion of the side panel  22 , and is supportingly connected to the fastener housings  130   a - 130   h  and  130   m - 130   n  and to the upper portion of the side panel  20 , the top panel  18 , and the upper portion of the side panel  22 . In a similar fashion, another continuous inner lip  146  extends forwardly from the support panel  26  in a parallel and spaced relationship with the lower portion of the side panel  20 , with the bottom panel  24 , and with the lower portion of the side panel  22 , and is supportingly connected to the fastener housings  132   a - 132   h  and  132   m - 132   n  and to the lower portion of the side panel  20 , the bottom panel  24 , and the lower portion of the side panel  22 . A segmented peripheral outer lip  148  extends forwardly along, about and from the top panel  18 , the side panels  20  and  22 , and the bottom panel  24 . The inner lip  144  intimately and sealingly engages the weather seal  60  and in a similar fashion the inner lip  146  intimately and sealingly engages the weather seal  64  as shown in  FIGS. 12 and 13 . Corresponding portions of the segmented peripheral outer lip  148  intimately and sealingly engage major portions of the weather seals  58  and  62 . 
     A filter assembly  150 , including a framed filter  152  consisting of mesh-like metal screen or EMI protective screen material or other such suitable material containing EMI protective material, is located in the air intake enclosure  30  to inhibit EMI emissions. Also visible is the centrifugal air pump  34  residing in the centrifugal air pump enclosure  32 . The front edge of a framed filter  154  having a mesh-like metal screen or EMI protective screen material or other such suitable material containing EMI protective material is visible just below the centrifugal air pump  34 . The framed filter  152  and the framed filter  154  are also useful for excluding insects from the interior of the LED display module  10 . 
     A cooling fan  156  mounts to an enclosure  158  which surrounds the electronics module  54 . Provision is also made for dedicated and directed air flow along and about the interior of the LED display module  10  incorporating a plurality of configured panels where some have air passage cutouts for managing airflow. A vertically oriented panel  160  including an air passage cutout  162  extends outwardly from the enclosure panel  28  and another vertically oriented panel  164  located adjacent to the air intake enclosure  30  extends outwardly from the support panel  26 . A plurality of horizontally oriented support panels  167   a - 167   c  extend substantially between the opposed sides  20  and  22  and along the support panel  26  to act as support structure for the LED display module latching system  36  and conveniently include interrupted air passage cutouts  169   a ,  169   b  and  169   c  located in close proximity to the fastener housings  130   k ,  130   l ,  130   m ,  132   k ,  132     1   and  132   m , and also include interrupted air passage cutouts  171   a ,  171   b  and  171   c  located in close proximity to the fastener housings  130   h ,  130   i ,  130   j ,  132   h ,  132   i  and  132   j  to assist in cooling air flow from an air intake enclosure inlet  190  ( FIG. 16 ), through the air intake enclosure  30 , through the framed filter  152 , through the air passage cutouts  169   a ,  169   b  and  169   c , through the upper part of the rear cover  16  containing an electronic assembly  166 , through the passage cutout  162 , through the upper part of the rear cover  16  containing an electronic assembly  168 , through the air passage cutouts  171   a ,  171   b  and  171   c , and through the centrifugal air pump  34  and the framed filter  154 , and thence overboard through an centrifugal air pump enclosure outlet  194  ( FIGS. 15 and 16 ) in the centrifugal air pump enclosure  32 . Such dedicated and directed airflow is also shown and described in  FIG. 17 . 
       FIG. 9  is an exploded side view of the upper LED display assembly  12  showing the alignment of the components forming the LED display assembly  12 . 
       FIG. 10  is an exploded partial view of some components of the LED display module  12  comprising the upper left corner of the louver panel  68  showing a partial view of components located in close relationship to the louver panel  68 , including, but not limited to, the overmold panel  70 , the LED printed circuit board  72 , and other components or features closely related thereto.  FIG. 11  is an assembled partial view and partially exploded view incorporating many of the components of  FIG. 10  showing part of the louver panel  68 , some of the view ports  100   a - 100   n , a portion of the support grid  93 , a portion of the overmold  70 , an LED package  170   a  shown distanced from the LED printed circuit board  72  and the view port  100   a , and an overmold cavity  174   a  separated from and distanced from the underlying overmold panel  70 . Part of the frame  80  is also shown. With reference to  FIG. 10  and/or  FIG. 11 , such components or features are now described. The LED printed circuit board  72  includes a plurality of forwardly oriented LED packages  170   a - 170   n , preferably surface mounted LED packages, mounted thereto. The LED packages  170   a - 170   n  can include one or more internally located LEDs, preferably of different colors, where there are multiple LEDs incorporated. Preferably, the body of the LED packages  170   a - 170   n , with the exception of the front portion which can be clear or translucent, is of a dark color, such as black, in order to contribute to display contrast and to minimize lateral light transmission. The transparent overmold panel  70  includes a plurality of forward extending overmold cavity view ports  174   a - 174   n  which are open to the rear to closely accommodate the forward portion of the plurality of LED packages  170   a - 170   n  for viewing therethrough. The general and planar structure of the overmold panel  70  is molded to the rear support grid  93  of the louver panel  68 , whereby the overmold cavity view ports  174   a - 174   n  extend through and project outwardly from and are viewable through the louver panel view ports  100   a - 100   n . The overmold cavity view ports  174   a - 174   n  are slightly smaller than the dimension of an opening  180  ( FIG. 10 ) of the continuous sub-lip  178  central to the louver panel view ports  100   a - 100   n , each being correspondingly co-located within the support grid  93 . A continuous angled surface  176  including four angled portions is located on the forward facing portion of the support grid  93 , whereby each continuous angled surface  176  forms part of each of the individual louver panel view ports  100   a - 100   n . The continuous sub-lip  178 , being part of and continuous with the support grid  93 , forms part of each of the individual louver panel view ports  100   a - 100   n  and extends inwardly from the inner periphery of each of the continuous angled surfaces  176  to create the opening  180  through which a greater part of the co-located LED packages  170   a - 170   n  and the overmold cavity view ports  174   a - 174   n  extend. The continuous angled surface  176 , the sub-lip  178 , and the opening  180  together form units of the louver panel view ports  100   a - 100   n . Both the overmold cavity view ports  174   a - 174   n  and the louver panel view ports  100   a - 100   n  are visible along the support grid  93 , whereby the overmold cavity view ports  174   a - 174   n  are viewable within the louver panel view ports  100   a - 100   n . Also, the combination of multiple angled surfaces  176  distributed along and about the front portion of the support grid  93 , along with the support grid  93 , forms a plurality of substantially similar louvers  179  distributed along and about the louver panel  68  for the purpose of physical and light shading protection of the LED packages  170   a - 170   n , as well as providing the same protective features for the overlying co-located overmold cavities view ports  174   a - 174   n.    
       FIG. 12  is an exploded view of some components closely associated with the upper left corner of the louver panel  68  showing a partial view of such components located in close relationship to the louver panel  68 . Shown in particular and substantially in two illustrations is the summary of relationships of multiple components which are in forced intimate contact to create suitable weather seals between the louver panel  68  to the rear cover  16 .  FIG. 13  is an assembled view of the components of  FIG. 12 . The components are brought together in a forcible fashion by the use of suitable fasteners, such as, but not limited to, screws and the like to cause intimate contact of various sealing surfaces or components. Also shown in particular is the relationship of the LED packages  170   a - 170   n  with a plurality of rearwardly facing openings  182  located within the overmold cavity view ports  174   a - 174   n.    
     One region of sealing is located between the louver panel  68  and the overmold panel  70 . More specifically, the generally planar forward portion of the overmold panel  70  intimately and forcibly contacts the rear portion of the support grid  93  and the continuous sub-lip  178  which are unitary in nature, thereby creating a seal there between. 
     Another region of sealing is located between the overmold panel  70  and the LED printed circuit board  72 . More specifically, the generally planar rearward portion of the overmold panel  70  intimately and forcibly contacts the LED printed circuit board  72  creating a seal therebetween to effectively seal the LED packages  170   a - 170   n  between the overmold panel  70 , including the overmold cavity viewports  174   a - 174   n , and the LED printed circuit board  72 . 
     Another region of sealing is located between the rear of the heat distribution plate  76  and the frame  80 . More specifically, the weather seal  78  is located between the rearward facing portion of the heat distribution plate  76  and the forward facing perimeter of the frame  80  just inside the peripheral lip  112  in intimate and forced contact therebetween. 
     Another region of sealing is located between the louver panel  68  and the frame  80 . More specifically, the peripheral lip  91  formed by the combined top panel  84 , the side panels  86  and  88 , and the bottom panel  90  of the louver panel  68  intimately, forcibly, overlappingly contacts and mutually engages the peripheral lip  112  of the frame  80 , whereby the latches  92  of the peripheral lip  91  of the louver panel  68  intimately and forcibly engage the catches  114  of the frame  80  in an interlocking relationship. Further sealing is accomplished by the addition of a suitable sealant  184  applied at the junction of the peripheral lip  112  and the peripheral lip  91  as shown in  FIG. 13 . 
     A region of double sealing, incorporating an intimate forcible contact, is located between the rear of the frame  80  and the front of the rear cover  16 . More specifically, an outer sealing relationship is provided by the weather seals  58  and  62  located between the rearward facing portion of the frame  80  just inside of the continuous peripheral lips  115  and the segmented peripheral outer lip  148  of the rear cover  16 . An inner sealing relationship is provided by the weather seals  60  and  64  which reside in the weather seal channels  126  of the frame  80  and the inner lip  144 , as well as the inner lip  146  of the upper and lower frames  80 , respectively. 
       FIG. 14  is a cross section view of the upper LED display module  12  along line  14 - 14  of  FIG. 3  showing the close and intimate relationship of the heat sinks  82   a - 82   n  to the heat distribution plate  76 , the thermal conductive pad  74 , and the LED printed circuit board  72 . Such an arrangement conducts and wicks heat from a plurality of various electronic components  186  secured to the LED printed circuit board  72 , from the plurality of LED packages  170   a - 170   n  and from the LED printed circuit board  72  through the thermal conductive pad  74  and the heat distribution plate  76  to the plurality of heat sinks  82   a - 82   n . The heat received by the plurality of heat sinks— 82   a - 82   n  is then dissipated with an evenly improved efficacy as provided by the airflow throughout the interior of the LED display module  10 , as later described in detail herein. 
       FIG. 15  is a rear view of the rear cover  16  showing the lower structure of the air intake enclosure  30  and the centrifugal air pump enclosure  32 . Cooling air  188  is drawn by action of the centrifugal air pump  34  through the air intake enclosure inlet  190  and circulated along a dedicated path within the LED display module  10  to absorb generated interior heat which is then forced outwardly as exhaust air  192  at an elevated temperature through the centrifugal air pump enclosure outlet  194 . Additional interior air flow is shown in  FIG. 17 . 
     The lower portion of the enclosure panel  28  serves as a mount and for accommodating a signal input receptacle  196 , a signal output receptacle  198 , a power receptacle  200 , and for a diagnostic display  202 . 
       FIG. 16  is an exploded front view of the rear cover  16  showing the filter assembly  150 , the centrifugal air pump  34 , the framed filter  154  and associated components distanced from the rear cover  16 . The filter assembly  150  includes the framed filter  152 , a seal  204 , and a plate  206  which suitably secures to the structure of the air intake enclosure  30  to assist in securing the framed filter  152  and the seal  204  to the structure of the air intake enclosure  30 . Tabs  208  on the lower edge of the framed filter  152  also assist in securing the framed filter  152  and the seal  204  to the structure of the air intake enclosure  30 . The centrifugal air pump  34  is suitably secured to the front edge of the centrifugal air pump enclosure  32  and the framed filter  154  is suitably secured to the centrifugal air pump enclosure outlet  194 . 
       FIG. 17  shows the rear cover  16  of the LED display module  10  showing airflow along the inner regions and components of the rear cover  16 . Shown in particular is the flow of cooling air  188  from the air intake enclosure  30 , through the framed filter  152 , through the air passage cutouts  169   a ,  169   b  and  169   c , through the upper part of the rear cover  16  containing an electronic assembly  166 , through the passage cutout  162 , through the upper part of the rear cover  16  containing an electronic assembly  168 , through the air passage cutouts  171   a ,  171   b  and  171   c , and thence through the centrifugal air pump  34  and the framed filter  154  in the centrifugal air pump enclosure  32  to exit through the centrifugal air pump enclosure outlet  194  ( FIG. 16 ) as exhaust air  192 , which includes heat drawn and extracted from the interior of the LED display module  10 . Such airflows correspondingly flow along the inner regions and components of the combined upper and lower LED display assemblies  12  and  14 . 
     MODE OF OPERATION 
     Operation of the invention incorporates the use of functions and features described herein, many of which may be viewed as static in nature. Non-static moving parts are incorporated by the use of the cooling fan  156  and the internally located centrifugal air pump  34 , the latter of which is incorporated to entrain and cause forced exit of generated heat from various electrical or electronic devices within the LED display module  10 . Such generated heat is gathered and absorbed by the use of the thermal conductive pad  74 , the heat distribution plate  76 , and is wicked off by the plurality of heat sinks  82   a - 82   n  and ultimately collected and forced externally by the centrifugal air pump  34 . 
     Static features are also included to enhance the functionability of the present invention. Superior weather sealing is incorporated by the use of the transparent overmold panel  70  which seals between the support grid  93  of the louver panel  68  and the LED packages  170   a - 170   n . Weatherability is enhanced by the use of overlapping and snap engagement of the peripheral lip  91  of the louver panel  68  with the peripheral lip  112  of the frame  80  and closely associated sealing by the adhesive  184  and further enhanced by the use of the region of a double sealing incorporating the intimate and forcible contact between the rear of the frame  80  and the front of the rear cover  16 . Viewability is enhanced by the use of the louver panel  68 , whereby each LED package  170   a - 170   n  is viewable on an individual basis through co-located overmold cavity view ports  174   a - 174   n  and louver panel view ports  100   a - 100   n . Electromagnetic interference is inhibited and suppressed by the use of materials, such as the heat distribution plate  76  acting as an RF shield in cooperation with the EMI suppressive qualities of components, such as, but not limited to, the rear cover  16 . 
     Various modifications can be made to the present invention without departing from the apparent scope thereof. 
     LED DISPLAY MODULE 
     PARTS LIST 
     
         
           10  LED display module 
           12  upper LED display assembly 
           14  lower LED display assembly 
           16  rear cover 
           18  top panel 
           20  side panel 
           22  side panel 
           24  bottom panel 
           26  support panel 
           28  enclosure panel 
           30  air intake enclosure 
           32  centrifugal air pump enclosure 
           34  centrifugal air pump 
           36  LED display module latching system 
           38  framework 
           40  actuator mechanism 
           42  actuator arms 
           44  latch housings 
           46  pivotable latches 
           48  handle 
           50  heat sink 
           52  gasket 
           54  electronics module 
           56  alignment posts 
           58  upper weather seal 
           60  upper weather seal 
           62  lower weather seal 
           64  lower weather seal 
           66  connector plate 
           68  access opening 
           70  louver panel 
           72  overmold panel 
           74  LED printed circuit board 
           76  thermal conductive pad 
           78  heat distribution plate 
           80  weather seal 
           82  frame 
           82   a - n  heat sinks 
           84  top panel 
           86  side panel 
           88  side panel 
           90  bottom panel 
           91  peripheral lip 
           92  latch 
           93  support grid (of louver panel  68 ) 
           94   a - n  supports 
           96   a - n  supports 
           100   a - n  louver panel view ports 
           102   a - n  engagement pins 
           103  notch 
           104  top panel 
           105  notch 
           106  side panel 
           108  side panel 
           110  bottom panel 
           112  peripheral lip 
           114  catch 
           115  peripheral lip 
           116  central panel 
           118   a - n  openings 
           120  notch 
           122  notch 
           124   a - n  pins 
           126  weather seal channel 
           128   a - n  threaded inserts 
           130   a - n  fastener housings 
           132   a - n  fastener housings 
           134  support grid (of frame  80 ) 
           136   a - n  supports 
           138   a - n  supports 
           140   a - n  pin receiver posts 
           142  cavity 
           144  inner lip 
           146  inner lip 
           148  segmented peripheral outer lip 
           150  filter assembly 
           152  framed filter 
           154  framed filter 
           156  cooling fan 
           158  enclosure 
           160  panel 
           162  air passage cutout 
           164  panel 
           166  electronic assembly 
           167   a - c  support panels 
           168  electronic assembly 
           169   a - c  air passage cutouts 
           170   a - n  LED packages 
           171   a - c  air passage cutouts 
           174   a - n  overmold cavity view port 
           176  continuous angled surface 
           178  continuous sub-lip 
           179  louvers 
           180  opening 
           182  openings 
           184  sealant 
           186  various electronic components 
           188  cooling air 
           190  air intake enclosure inlet 
           192  heated exhaust air 
           194  centrifugal air pump enclosure outlet 
           196  signal input receptacle 
           198  signal output receptacle 
           200  power receptacle 
           202  diagnostic display 
           204  seal 
           206  plate