Abstract:
A lamp includes a shell and an LED bulb including a heat sink enclosed by the shell. The shell defines at least a hole at a lower portion of the shell and at least an aperture at an upper portion of the shell. The LED bulb includes a heat sink enclosed by the shell. At least an LED is mounted at a bottom of the heat sink. The heat sink includes a plurality of fins extending from top to bottom. The fins define a plurality of channels therebtween. The channels are in flow communication with at least hole and the at least aperture of the shell.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to an LED lamp, and particularly to an LED lamp having a heat sink and a shell enclosing the heat sink for heat dissipation. 
         [0003]    2. Description of Related Art 
         [0004]    The technology of light emitting diode (LED) has been 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. Nevertheless, the rate of heat generation increases with the illumination intensity. This issue has become a challenge for engineers to design the LED illumination, i.e. the LED lamp. 
         [0005]    A related LED lamp includes a heat sink and a plurality of LED modules including LEDs, attached to an outer surface of the heat sink to enable dissipation of heat generated by the LEDs. In order to provide a high brightness, a reflector is mounted on the LED lamp to cover the heat sink, whereby light generated by the LEDs is repeatedly reflected by the reflector downwardly. However, ambient air around the heat sink is heated to flow upwardly, and then accumulates at a top of the reflector, making dissipation of the heat become problematic. 
         [0006]    What is needed, is an LED lamp which has greater heat-transfer and heat dissipation capabilities, whereby the LED lamp can operate normally for a sufficiently long period of time. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Many aspects of the disclosure 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 disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0008]      FIG. 1  is a side view of an LED lamp in accordance with a first embodiment of the present disclosure, wherein a cross-sectional of a shell of the LED lamp is shown. 
           [0009]      FIG. 2  is a view similar to  FIG. 1 , but showing an LED lamp in accordance with a second embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Referring to  FIG. 1 , an LED (light emitting diode) lamp  10  in accordance with a first embodiment of the disclosure is illustrated. The LED lamp  10  comprises an LED bulb  12  and a shell  16  enclosing the LED bulb  12 . The LED bulb  12  includes a heat sink  121 , an LED module  120  mounted at a bottom of the heat sink  121 , and a connector  124  engaging at a top of the heat sink  121 . A lamp holder  14  is installed in the shell  16  for electrically engaging the connector  124  of the LED bulb  12 . In this embodiment, the shell  16  has a height larger than that of the whole LED bulb  12 . 
         [0011]    The heat sink  121  comprises a heat conducting body (not labeled), and a plurality of radial partition fins  1210  extending from an outer surface of the body. The radial partition fins  1210  extend along a direction from top to bottom. Two neighboring fins  1210  are spaced apart from one another with a channel therebetween. The LED module  120  comprises a plurality of LEDs (not labeled) installed at the bottom of the heat conducting body. A hemispherical, transparent cover  125  is engaged with the bottom of the heat sink  121  and covers the LED module  120 . The transparent cover  125  is so dimensioned and positioned that bottom intakes of the channels between the fins  1210  are exposed downward to the surrounding air, without being blocked by the cover  125 . Thus, air can easily flow upwardly along the cover  125  into the channels between the fins via the bottom intakes thereof. 
         [0012]    The shell  16  is inverted frustum-shaped and comprises a top plate  161 , a bottom plate  163  and a lateral wall  162  interconnecting with the top plate  161  and the bottom plate  163 . The lamp holder  14  is mounted at the top plate  161  for connecting the connector  124  of the LED bulb  12 . The lateral wall  162  is around the LED bulb  12  and has an angled inner surface  164  defined at an acute angle with respect to the bottom plate  163 . The lateral wall  162  can be made of metal material which can reflect light. The bottom plate  163  is transparent. A part of light generated by the LED module  120  radiates downwardly directly through the transparent bottom plate  163 . Another part of the light generated by the LED module  120  is reflected by the inner surface  164  of the lateral wall  162  to radiate downwardly through the transparent bottom plate  163 . The lateral wall  162  defines a plurality of apertures  160  at a top portion thereof near a top of the heat sink  121 ; in other words, the apertures  160  is near outlets of the channels of the heat sink  121 . The bottom plate  163  defines a plurality of holes  1630  near an edge thereof. The holes  1630  corresponds to the channels defined between the fins  1210 . 
         [0013]    According to the present disclosure, heat produced by the LED module  120  can be quickly transferred to the heat sink  121  via a thermal connection between the LED module  120  and the heat conducting body. The heat is transferred to the fins  1210 , and is then dissipated away to ambient air via the fins  1210 . Air in the channels defined between the fins  1210  is heated. The channels each function as a chimney for guiding the heated air to flow upwardly and outwardly to the apertures  160  of the lateral wall  162 . The heated air is replaced by outside cooler air flowing from the holes  1630  of the bottom plate  163  into the shell  16  and toward the channels. By the provision of the channels in flow communication with the lower holes  1630  and the upper apertures  160 , a natural air convection through the channels between the fins  1210  can be established, whereby the heat dissipation efficiency of the heat sink  121  can be improved. Thus, the heat produced by the LEDs can be removed by the heat sink  121  very quickly, thereby enabling the LED module  120  to work within a required temperature range. 
         [0014]    Alternatively, the holes  1630  can be defined at a bottom portion of the lateral wall  162 . The connector  124  can be designed to insert in the holder  14  to electrically connect the holder  14 . The connector  124  of the LED bulb  12  can be standard component and available in the market, such as E26, E27, GU10, PAR30 or MR16. Furthermore, when the LED lamp  10  is used in an inverted position, the heated air in the channels among the fins  1210  flows upwardly and outwardly to the holes  1630  of the lateral walls  160 , and replaced by outside cooler air flowing through the apertures  1630  of the bottom plate  163  into the shell  16 . 
         [0015]    Referring to  FIG. 2 , an LED lamp  20  in accordance with a second embodiment of the disclosure is illustrated. The LED lamp  20  comprises an LED bulb  22  and a shell  26  enclosing the LED bulb  22 . The LED bulb  22  includes a heat sink  221 , an LED module  220  with a plurality of LEDs (not labeled) mounted at a bottom of the heat sink  221 , a transparent cover  225  covering the LED module  220 , and a connector  224  engaging at a top of the heat sink  221 . The heat sink  221  has a plurality of radial partition fins  2210 . The shell  26  is inverted frustum-shaped and comprises a top plate  261 , a bottom plate  263  and a lateral wall  262  interconnecting with the top plate  261  and the bottom plate  263 . The lateral wall  262  defines a plurality of apertures  260  at a top portion thereof, and the bottom plate  263  defines a plurality of holes  2630  near an edge of thereof. 
         [0016]    Different from the LED lamp  10  of the first embodiment, the LED module  220  and the cover  225  of the LED lamp  20  extend through the bottom plate  263  of the shell  26 . The heat sink  221  is received in the shell  26 . The bottom plate  263  of the shell  26  is installed between the heat sink  221  and the LED module  220 . In other words, the shell  26  has a height less than that of the whole LED bulb  22 . Heat produced by the LED module  220  can be quickly transferred to the fins  2210 . The air in the channels defined between the fins  2210  is heated to flow out of the apertures  260  and replaced by cooler air flowing into the shell  26  from the holes  2630 . Since the shell  26  has a height less than that of the whole LED bulb  22 , air flowing through the shell  26  from bottom to top thereof is more quick than air flowing through the shell  16  of the first embodiment. 
         [0017]    It is to be understood, however, that even though numerous characteristics and advantages of various embodiments have been set forth in the foregoing description, together with details of the structures and functions 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 disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.