Patent Publication Number: US-7722222-B2

Title: LED lamp assembly

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an LED lamp assembly, and more particularly to an LED lamp assembly emitting light at opposite sides thereof. 
   2. Description of Related Art 
   The technology of light emitting diodes has rapidly developed in recent years from indicators to illumination applications. With the features of long-term reliability, environment friendliness and low power consumption, the LED is viewed as a promising alternative for future lighting products. 
   A conventional LED lamp comprises a heat sink and a plurality of LED modules having LEDs attached to an outer surface of a heat sink to dissipate heat generated by the LEDs. The outer surface of the heat sink generally is a plane and the LEDs are arranged close to each other. When the LED lamp works, the LEDs mounted on the planar outer surface of the heat sink only form a flat light source, whereby the illumination area of the LED lamp is limited. In addition, the heat sink of the conventional LED lamp cannot efficiently dissipate the heat generated by the LEDs. 
   What is needed, therefore, is an LED lamp assembly having a large illumination area. Furthermore, the LED lamp assembly has a high heat dissipation efficiency. 
   SUMMARY OF THE INVENTION 
   An LED lamp assembly includes a pair of LED lamps. Each of the LED lamps includes a heat sink having a heat absorbing portion and a heat dissipating portion. The heat absorbing portion has a first surface and a second surface opposite to the first surface. The heat dissipating portion extends rearwards from the first surface of the heat absorbing portion. An outmost end of the heat dissipating portion defines a plurality of apertures and is located beyond an outmost end of the heat absorbing portion. The heat absorbing portions of the heat sinks of the LED lamps are located at opposite sides of the LED lamp assembly. The heat dissipating portions of the heat sinks are oriented towards each other. A channel is between the heat dissipation portions and communicates with the apertures. The LED modules are mounted at the second side the heat absorbing portions. Heat generated by the LED modules is transmitted to the heat absorbing portions of the heat sinks and then dissipated to a surrounding air through the apertures and the channel via the heat dissipating portions. 
   Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
       FIG. 1  is a front elevational view of a lamp assembly in accordance with a preferred embodiment of the present invention; 
       FIG. 2  is an exploded view of  FIG. 1 ; and 
       FIG. 3  is an inverted view of  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 1-2 , an LED lamp assembly (not labeled) comprises a pair of LED lamps (not labeled) symmetrical about each other. Each LED lamp comprises a heat sink  10 , a plurality of LED modules  20  mounted on the heat sink  10 , a reflector  30  mounted on the heat sink  10  and surrounding the LED modules  20 , a transparent envelope  40  mounted around a periphery of the heat sink  10  to enclose the LED modules  20  and the reflector  30  therein. A lamp holder  50  is located at a top of the LED lamp assembly. A receiving member  60  is located at a bottom of the LED lamp assembly. The lamp holder  50  is configured for connecting with a supporting post so that the lamp assembly can be used as a suspension lamp. A driving circuit module (not shown) is received in the receiving member  60  for electronically connecting with the LED modules  20 . A pair of S-shaped strips  80  is mounted on opposite sides of the LED lamp assembly to decorate the LED lamp assembly. 
   Referring to  FIG. 3  also, the heat sink  10  of the LED lamp comprises a heat absorbing portion  11 , an elongated connecting portion  15  extending outwardly from a centre of a rear surface (not labeled) of the heat absorbing portion  11 , and a heat dissipating portion  13  extending from the rear surface of the heat absorbing portion  11  and around the connecting portion  15 . 
   The heat absorbing portion  11  comprises a circular heat absorbing plate  111  and an annular sidewall  113  extending outwardly from an edge of the heat absorbing plate  111 . The LED modules  20  are mounted on a front surface (not labeled) of the heat absorbing plate  111 . The LED modules  20  are horizontally arranged from a top to a bottom of the front surface with a predetermined distance defined between two neighboring LED modules  20 . The sidewall  113  encloses the LED modules  20  therein. The sidewall  113  forms a plurality of protruding portions  115  from an inner surface thereof. The protruding portions  115  are equidistantly spaced from each other and provided for engaging with the envelope  40 . 
   The connecting portion  15  is mounted on the rear surface of the heat absorbing plate  115  and opposite ends thereof connects with the lamp holder  50  and the receiving member  60 . The connecting portion  15  defines an elongated groove (not labeled) at a centre thereof. The groove of the connecting portion  15  communicates with the receiving member  60 . Thus, wires (not shown) of the driving circuit module extend through the groove of the connecting portion  15  to electronically connect with the LED modules  20 . The connecting portion  15  forms a plurality of mounting members  151  at opposite sides thereof. The connecting portions  15  of the heat sinks  10  are oriented towards each other. A plurality of screws (not shown) extends through the mounting members  151  of the heat sinks  10  to assemble the two LED lamps together. An rear side  153  of the connecting portion  15  is located in rear of a rear side (not labeled) of the heat dissipating portion  13 . Thus, the heat dissipating portions  13  of the heat sinks  10  of the LED lamps are spaced from each other when the rear sides  153  of the connecting portions  15  of the two heat sinks  10  are abuttingly assembled together. Accordingly, a channel is defined between the heat dissipating portions  13  of the heat sinks  10  and around the connecting portions  15 . An airflow can flow from a bottom to a top of the channel between the heat dissipating portions  13  of the heat sinks  10  of the LED lamp assembly to dissipate heat generated by the LED modules  20 . 
   The heat dissipating portion  13  comprises a plurality of radial fins  131  and a sidewall  133  connecting the fins  131  and enclosing outmost ends of the fins  131  therein. The fins  131  are mounted on the rear surface of the heat absorbing plate  111  of the heat absorbing portion  11  and spaced from each other. Inner ends of the fins  131  are near to the opposite lateral sides of the connecting portion  15 . The outmost ends of the fins  131  extend outwardly beyond an outmost edge (not labeled) of the heat absorbing plate  111  of the heat sink  10 . Thus, an annular area (not labeled) is formed between the sidewall  133  and the outmost edge of the heat absorbing plate  111  of the heat absorbing portion  11 . A plurality of apertures  135  is defined in the annular area. Each aperture  135  is defined between two neighboring fins  131 , the outmost edge of the heat absorbing plate  111  and the sidewall  133 . The apertures  135  are communicated with and guide airflow into the channel between the heat sinks  10 . 
   Each LED module  20  comprises an elongated printed circuit board  22  and a plurality of spaced LEDs  24  evenly mounted on a side of the printed circuit board  32 . The LEDs  24  of each LED module  20  are arranged along a longitudinal direction of the printed circuit board  22 . Each LED module  20  is mounted in a thermally conductive relationship with the front surface of the heat absorbing plate  111  of the heat absorbing portion  11  and electronically connects with the driving circuit module. 
   Each reflector  30  has a circular configuration and comprises a mounting portion  33  and a reflecting portion  31  located within the mounting portion  33 . 
   The mounting portion  33  is a circular plate and enclosed in the sidewall  113  of the heat absorbing portion  11 . Screws extend through the edges of the mounting portion  33  and engage with the heat absorbing portion  11  to mount the reflector  30  on the heat sink  10 . The reflecting portion  31  comprises a rectangular plate  313  with a row of through holes  311 . A plurality of linear reflecting plates  315  each extends downwardly and frontwards from a corresponding rectangular plate  313  with a predetermined distance. Each through hole  311  corresponds to a corresponding LED  24 . Each reflecting plate  315  has a length similar to that of the LED module  20  and reflects light emitted from the LED module  20  to enhance the illumination of the LED lamp. 
   The envelope  40  has a disc-like configuration and is made of glass or transparent plastic. The envelope  40  defines a plurality of through holes  41  corresponding to the protruding portions  115  of the heat absorbing portion  11 . Screws (not shown) extend through the through holes  41  of the envelope  40  and engage with the protruding portions  115  of the heat absorbing portion  11  to mount the envelope  40  on the heat absorbing portion  11 . The envelope  40  and the heat absorbing portion  11  define a space (not labeled) accommodating the LED modules  20  and the reflector  30  therein, whereby the LED modules  20  can have a sufficient protection for avoiding a damage caused by an unexpected force acting on the LED lamp. A gasket  70  is sandwiched between the envelope  40  and the sidewall  113  of the heat absorbing portion  11  to provide the space with a waterproof capability. 
   In use, when the LEDs  24  emit light, the light is reflected by the reflector  30 . Heat generated by the LEDs  24  is absorbed by the heat absorbing portions  11  of the heat sinks  10 . The heat is then transferred to the heat dissipating portions  13 . Finally the heat is dispersed into ambient cool air through the fins  131 . The air in the apertures  135  at the annular periphery of each of the heat sinks  10  and in the channel between the heat sinks  10  is heated. The heated air becomes lighter than the cool air, so that the heated air floats upwardly due to buoyancy and is replaced by the outside cooler air flowing upwardly from the bottom to the top of the heat sinks  10  into the heat sinks  10 . The apertures  135  in the annular area of the heat sink  10  guide the airflow into the channel between the heat sinks  10 , whereby the heat of the heat sinks  10  and accordingly the heat generated by the LEDs  24  of the LED module  20  can be effectively dissipated. Thus, the LED lamp assembly in accordance with the present invention has an improved heat dissipating efficiency for preventing the LEDs from overheating. 
   It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.