Patent Publication Number: US-2012043885-A1

Title: Led lamp with circling led modules and encapsulation

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure generally relates to LED lamps, and particularly to a LED lamp with an encircled LED modules and encapsulation 
     2. Description of the Related Art 
     Light emitting diodes (LEDs) have many advantages, such as high luminosity, low operational voltage, low power consumption, compatibility with integrated circuits, easy driving, long-term reliability, and environmental friendliness. All of these reasons have promoted the LEDs as a widely used light source. Light emitting diodes are commonly applied in lighting applications. 
     LED illumination apparatuses must overcome heat dissipation challenges. An LED lamp is commonly arranged with LED lighting module on the top and heat dissipation element at the periphery. The heat dissipation efficiency of LED lamp is limited. This will reduce the lifespan of the LED lamp. Also, the LED lamp will be too hot to touch during disconnection. This adds to the inconvenience of using the LED lamp. 
     What is needed, therefore, is an LED lamp, which can improve heat dissipation efficiency and convenience of using the lamp, and ameliorate the described limitations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the disclosure can be better understood with reference to the drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the LED lamp. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the views. 
         FIG. 1  is a schematic cross section of an LED lamp in accordance with a first embodiment. 
         FIG. 2  is a schematic cross section of an LED lamp in accordance with a second embodiment. 
         FIG. 3  is a schematic cross section of an LED lamp in accordance with a third embodiment. 
         FIG. 4  is a schematic cross section of an LED lamp in accordance with a fourth embodiment. 
         FIGS. 5-7  are schematic front views of heat dissipation elements. 
         FIG. 8  is a schematic cross section of an LED lamp in accordance with a fifth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of an LED lamp as disclosed are described in detail here with reference to the drawings. 
     Referring to  FIG. 1 , an LED lamp  10  in accordance with a first embodiment includes at least one LED module  12 , an electrical sleeve  14 , a heat dissipation element  16 , and an encapsulation  18 . The at least one LED module  12  is arranged evenly on the surface of the heat dissipation element  16  for thermally conducting the heat from the at least one LED module  12  to the heat dissipation element  16 . The heat dissipation element  16  includes one fixable end  162  for fixing to the electrical sleeve  14  and one heat dissipation end  164  opposite to the fixable end  162  and exposed to air. 
     In this embodiment, the heat dissipation end  164  is planar and is at the top portion of the LED lamp  10 , and the heat dissipation element  16  is an inverted trapezoidal hollow body. The heat dissipation element  16  can be Cu, Sn, Al, Au, Ag, Mo, W, Mg, or an alloy thereof, or ceramic material such as AlO, AlN, or BeO. The heat dissipation element  16  can also be high radiant material, such as Alumite, with emissivity exceeding 0.7. The electrical sleeve  14  connects to an electrical connection base (not shown), for example, a bulb socket, for power supply. The electrical sleeve  14  can be E14, E17, E26, E27, GU10, PAR30, or MR16 type. 
     The encapsulation  18  encircles the at least one LED module  12  on the heat dissipation element  16  and covers a part of the heat dissipation element  16 . The encapsulation  18  connects to the electrical sleeve  14  near the fixable end  164  of the heat dissipation element  16 . The encapsulation  18  includes a top end  182  opposite to the electrical sleeve  14 . The top end  182  is a plane and coplanar with the heat dissipating end  164  of the heat dissipation element  16 . The encapsulation  18  can be resin, epoxy, silicone, polycarbonate (PC), noryl, polybutylene terephthalate (PBT), polyphthalamide (PPA), polypropylene (PP), polymethyl methacrylate (PMMA), glass fiber, TiO 2 , CaCO 3 , or a combination thereof. The encapsulation  18  is not thermal conductive so that the temperature of the encapsulation  18  will be lower than that of the heat dissipation element  16 . 
     The at least one LED module  12  is electrically connected to the electrical sleeve  14  through a circuit board (not shown) for supplying power. Thus, the electrical conductive path and the thermal conductive path of the LED lamp  10  are separated. The encapsulation  18 , which is not thermal conductive will be the main contact (gripping) part of the LED lamp when disconnecting the LED lamp from the power supply. The heat dissipating end  164  of the heat dissipation element  16  is exposed to air for heat dissipation. 
     Referring to  FIG. 2 , an LED lamp  10 A in accordance with a second embodiment includes at least one LED module  12 , an electrical sleeve  14 , a heat dissipation element  16 , and an encapsulation  18 . The only difference from the LED lamp  10  of  FIG. 1  is that the heat dissipation element  16  is an inverted trapezoidal solid body for improving heat dissipation efficiency. The heat dissipation element  16  of  FIG. 1  is hollow for reducing a weight thereof. 
     Referring to  FIG. 3 , an LED lamp  10 B in accordance with a third embodiment includes at least one LED module  12 , an electrical sleeve  14 , a heat dissipation element  16 , and an encapsulation  18 . The only difference from the LED lamp  10  of  FIG. 1  is that the heat dissipation element  16  is a rectangular hollow body. 
     Referring to  FIG. 4 , an LED lamp  10 C in accordance with a fourth embodiment includes at least one LED module  12 , an electrical sleeve  14 , a heat dissipation element  16 , and an encapsulation  18 . The only difference from the LED lamp  10  of  FIG. 1  is that the heat dissipation element  16  is a trapezoidal solid body. 
       FIGS. 5-7  are schematic front views of heat dissipation elements. The heat dissipation element  16  is a conical body with the at least one LED module  12  arranged in column in  FIG. 5 . The heat dissipation element  16  is a stepped cylinder in  FIG. 6 . The heat dissipation element  16  is a funnel with curved surface in  FIG. 7 . The heat dissipation element  16  can be polyhedron with multiple LED modules  12  arranged symmetrically thereon. 
     Referring to  FIG. 8 , an LED lamp  10 D in accordance with a fifth embodiment includes at least one LED module  12 , an electrical sleeve  14 , a heat dissipation element  16 , and an encapsulation  18 . The only difference from the LED lamp  10  of  FIG. 1  is that the encapsulation  18  further includes a reflection or refraction element  184 . The reflection or refraction element  184  can be at the outer surface or inner surface of the encapsulation  18 . In this embodiment, the reflection or refraction element  184  is at the outer surface of the encapsulation  18 . 
     It is to be understood, however, that even though numerous characteristics and advantages of the disclosure have been set forth in the foregoing description, together with details of the structures and functions of the embodiment(s), 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 disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.