Patent Publication Number: US-8109657-B2

Title: LED lamp

Description:
BACKGROUND 
     1. Technical Field 
     The disclosure relates to illumination devices and, particularly, to an LED (light-emitting diode) lamp having a good waterproof performance 
     2. Description of Related Art 
     LEDs are well known solid state light sources, in which current flows in a forward direction through a junction of two different semiconductors. Electrons and cavities combine at the junction to generate light. LEDs provide advantages of resistance to shock and practically limitless lifetime under specific conditions. When deployed in a lamp, LEDs offer a cost-effective yet high quality alternative to incandescent and fluorescent light fixtures. 
     When the LED lamp is used outdoors for illumination, dust and moisture may enter the LED lamp, causing current leakage or short circuit, or contamination of the LEDs. 
     What is needed, therefore, is an LED lamp which can overcome the described limitations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present apparatus 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 apparatus. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an isometric, assembled view of an LED lamp in accordance with an embodiment of the disclosure. 
         FIG. 2  is an exploded view of the LED lamp of  FIG. 1 . 
         FIG. 3  is an inverted, exploded view of the LED lamp of  FIG. 1 . 
         FIG. 4  is an enlarged, inverted view of a combination of a heat sink and a cover plate of the LED lamp of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , an LED lamp in accordance with an embodiment of the disclosure can be applied outdoors for illumination and has a good waterproof performance. The LED lamp comprises a hollow lamp housing  10 , a heat sink  20  received in the lamp housing  10 , an LED module  30  mounted on the heat sink  20 , and a transparent envelope  40  mounted on the heat sink  20  and correspondingly covering the LED module  30 . 
     Referring to  FIGS. 3 and 4  also, the lamp housing  10  has a configuration like a rectangular lantern and defines a cavity  12  inside the lamp housing  10 . The lamp housing  10  is cuboid-shaped and comprises four upright lateral plates  120  and a cover plate  14 . The four lateral plates  120  are hollowed out. The hollow-out four lateral plates  120  each define a light-emergent window  17 , for light emitted by the LED module  30  radiating out of the lamp. Four transparent boards  16  are further provided to the lamp housing  10  and secured to the four lateral plates  120 , respectively. The transparent boards  16  correspondingly cover the light-emergent windows  17 , respectively. The transparent boards  16  are disposed in the cavity  12  inside the lamp housing  10 . Four hollow-out decorated brackets  18  extend outwardly and diagonally from joints of every two adjacent lateral plates  120 , respectively. The cover plate  14  defines a rectangular opening  140  at a center thereof. 
     The cover plate  14  further comprises four spaced first mounting members  100  extending downwardly from a circumference of the cover plate  14 . Four screws (not shown) are extended through the four first mounting members  100 , and then screwed into the lateral plates  120 , for securing the cover plate  14  on the lateral plates  120 . The cover plate  14  further comprises four spaced second mounting members  200  extending downwardly from the cover plate  14  around the opening  140 . Each of the second mounting members  200  is L-shaped and comprises a first arm (not labeled) extending perpendicularly from the cover plate  14  and a second arm (not labeled) extending perpendicularly from the first arm. The heat sink  20  is fixed on and supported by the second arms of the four second mounting members  200 , whereby the heat sink  20  is securely received in the opening  140  of the cover plate  14  and the cavity  12  of the lamp housing  10 . Additionally, a driving module (not labeled) is fixed on a bottom face of the cover plate  14 . 
     The heat sink  20  is integrally made of a metal with good heat conductivity such as aluminum, copper or an alloy thereof. The heat sink  20  comprises a rectangular base  22  and a plurality of fins  24  extending outwardly from the base  22 . The base  22  is a rectangular plate. An annular receiving groove  220  is defined on a bottom face of the base  22  for correspondingly receiving an annular gasket  300  therein. A circular mounting portion  222  is formed at a central area of the base  22  and surrounded by the receiving groove  220 . The LED module  30  is attached on the mounting portion  222  and thermally connects therewith. The base  22  has a size substantially the same as that of the opening  140  of the cover plate  14 . When the heat sink  20  is assembled to the lamp housing  10 , the base  22  of the heat sink  20  is fittingly fixed on the four second mounting members  200  of the cover plate  14 , and the fins  24  are extended through the opening  140  of the cover plate  14  and exposed in an outer environment. 
     The LED module  30  comprises a circular printed circuit board  32  and a plurality of LEDs  34  mounted on the printed circuit board  32 . The printed circuit board  32  is attached on the mounting portion  222  of the heat sink  20 . The LEDs  34  are soldered on the printed circuit board  32  and spaced evenly from each other. 
     The envelope  40  is integrally formed of a transparent or semitransparent material such as glass, resin or plastic. The envelope  40  comprises a recessed body  41  and an engaging flange  42  extending outwardly and horizontally from a periphery of the body  41 . The engaging flange  42  of the envelope  40  has a size slightly larger than that of the receiving groove  220  of the heat sink  20 , whereby the receiving groove  220  is fittingly covered by the engaging flange  42 . When the envelope  40  is assembled to the heat sink  20 , the gasket  300  is sandwiched between the engaging flange  42  and the base  22  defining the receiving groove  220 , so that the envelope  40  is hermetically connected to the heat sink  20  and a receiving chamber (not labeled) for accommodating the LED module  30  is cooperatively defined between the heat sink  20  and the envelope  40 . A plurality of screws (not shown) are used to extend through the engaging flange  42  and threadedly engage in the bottom face of the base  22 . 
     A tubular mounting seat  400  is further provided to the LED lamp, for mounting the LED lamp to a lamp post (not shown) securely mounted at, for example, a roadside. The mounting seat  400  is fixed to the heat sink  20  and located at a top side of the LED lamp to be hung to a lamp pole. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the apparatus and function of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.