Patent Publication Number: US-6713956-B2

Title: Display module including a plate for heat dissipation and shielding

Description:
FIELD OF THE INVENTION 
     The present invention relates to a display module, especially to a display module with excellent heat-dissipation effect and more uniform light. 
     BACKGROUND OF THE INVENTION 
     The light emitting diodes (LED) are extensively used in indication and illumination application. The LEDs are generally made of direct-bandgap material with two electrodes. The electrical power is applied through the electrodes to generate electron and hole pair. The electron and hole pair is recombined to emit light. The LED can be roughly classified to visible light LED and infrared LED according to the emitting wavelength thereof. The LEDs have salient properties over the conventional light bulb such as compact volume, lower power consumption, lower thermal radiation and long life. Therefore, the LEDs are extensively used in indication usage in place of light bulb. 
     Moreover, as the advent and maturity of high brightness LED, the application of LEDs is broadened to compass bulletin board. The high brightness LEDs have the advantages of broad view angle, stable picture, easy assembling and thin thickness. The full color high brightness LED is realized as the high brightness LEDs of three primitive colors are successfully developed. 
     FIG. 1 shows the sectional view of prior art LED display panel. The LEDs  11   a  are arranged in 3×3, 4×4, or 4×8 array and assembled to a display module  1   a . A plurality of display modules  1   a  are assembled to a larger display panel. The LEDs  11   a  are packaged by epoxy resin and soldered to a printed circuit board  12   a . Afterward, the LEDs  11   a  are arranged within a shade  13   a  formed by mold ejection and are retained by filling resin  14   a . The shade  13   a  provides a sun blind  131   a  for the LEDs  11   a.    
     However, the display module la has not satisfactory heat dissipation effect such that the heat caused by insolation or driving of the LEDs cannot be easily dissipated. The performance of the display module  1   a  is degraded. 
     SUMMARY OF THE INVENTION 
     It is the object of the present invention to provide a display module with excellent heat-dissipation effect and more uniform light. 
     To achieve above object, the present invention provides a display module comprising a plurality of light emitting elements, a metal plate, a circuit board and a display panel. The light emitting elements and the circuit board are arranged on the metal plate, and the light emitting elements are wire bonded to the circuit board. A lens is formed atop the light emitting element. The metal plate is arranged with the light emitting elements and the circuit board is positioned on lateral side or around the display panel. The metal plate provides excellent heat-dissipation effect and the light emitting elements can emit more uniform light. 
     The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which: 
    
    
     BRIEF DESCRIPTION OF DRAWING 
     FIG. 1 shows the sectional view of prior art LED display panel; 
     FIG. 2 shows the sectional view of the present invention; and 
     FIG. 3 shows the perspective view of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference now to FIGS. 2 and 3, the present invention provides a display module  1  composed of a plurality of light emitting elements  11 , a metal plate  12 , a circuit board  13  and a display panel  14 . The light emitting elements  11  are fitted through holes formed in the circuit board and are pasted in a row to the metal plate  12  by insulative thermal glue  15 . The light emitting elements  11 , for example, can be LEDs and wire bonded to the circuit board  13  by conductive wire  16  such that the LEDs are electrically connected to copper trace on the circuit board. Afterward, the wire bonded LED is encapsulated by epoxy material to form a lens  17  thereon. As shown in FIG. 3, the light emitting elements  11  in a row are arranged on lateral side or around the display panel  14 . The display panel  14  can be made of acrylic or polyethylene material and be of rectangular or circular shape. The display panel  14  may be coated with lacquer or adhesive tapes (not shown) may be pasted to the backside and lateral sides thereof. The adhesive tapes are of black or white acrylic material to block light or reflect light. A plurality of display modules  1  are assembled into a larger display panel. 
     The light from the light emitting elements  11  uniformly impinge into the display panel  14  for display graphic or text on the display panel  14 . The metal plate  12  and the display panel  14  form a T-shape with extension portions of the metal plate being used for sunproof function. The metal plate also dissipates the heat of the light emitting elements  11 . 
     Moreover, the light emitting elements  11  can be of same color or different color such that the light emitting elements  11  have better color mixing effect than conventional LEDs. Moreover, the light emitting elements  11  form non-granular light dot, which is suitable for both near- and far-distance display. 
     In the present invention, the metal plate  12  provides excellent heat-dissipation effect to facilitate the light emitting elements  11  being operated at large current. The light emitting elements  11  can emit more uniform light and the display panel  14  can also uniform the light. 
     To sum up, the LED display module according to the present invention has following advantages: 
     (1). The LEDs are directly bound to the metal plate, thus having excellent heat-dissipation effect. 
     (2). The metal plate also has sunproof function. 
     (3). The LED display module has satisfactory color-mixing effect. 
     Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have suggested in the foregoing description, and other will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.