Patent Publication Number: US-2011069500-A1

Title: Heat Dissipation Module For Bulb Type LED Lamp

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The invention generally relates to LED lamps, particularly to heat dissipation modules for LED lamps. 
     2. Related Art 
     Light Emitting Diodes (LED) have various advantages such as low energy consumption, low heat, long durability, small size and fast response. Thus the LEDs have been replacing conventional lamps. The LEDs must be placed on a circuit board to form an LED module. Additionally, the LED module is usually associated with a heat sink to prevent from overheating. 
     However, this structure will invite a problem of uneven heat conduction. Because the LED module thermally contacts a part of the heat sink, only that part of the heat sink can provide higher thermal conductivity. Thus the heat from the LED module can not be rapidly dissipated. The interior of the heat sink will receive uneven thermal stress. The heat sink may be damaged by the thermal deformation. Additionally, the durability of the LED module may be shortened due to the insufficient thermal conductivity. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to rapidly and evenly dissipate the heat from the LED module. 
     To accomplish the abovementioned object, the invention provides a heat dissipation module, which comprises a heat dissipation assembly and a heat conducting element. The heat dissipation assembly includes a cylinder provided with a central hole. The central hole tapers off inwards to form two corresponding inclined surfaces. The heat conducting element, which is accommodated in the central hole, has a heat-absorbing section and two heat-releasing sections extending from the heat-absorbing section and being in contact with the inclined surfaces. 
     The heat conducting element has a heat-absorbing section and two heat-releasing sections, so directly thermal contact can be formed between the heat conducting element and LED or heat dissipation assembly. The heat dissipation efficiency can be improved. 
     Additionally, walls of the central hole have the same thickness, so the heat from the LED can be rapidly and effectively released by the walls. 
    
    
     
       BRIEF DESCRIPTION OF THE INVENTION 
         FIG. 1  is an exploded view of the invention; 
         FIG. 2  is a perspective view of the invention; 
         FIG. 3  is a sectional view of the invention; 
         FIG. 4  is a perspective view of the invention in use; 
         FIG. 5  is a sectional view of the invention in use; and 
         FIG. 6  is a sectional view of another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , the heat dissipation module for a bulb type LED lamp of the invention is essentially composed of a heat dissipation assembly  10  and a sheet-shaped heat conducting element  20 . The heat dissipation module can be connected to an LED module  40  by a mounting plate  30 . By this arrangement, the heat from the LED module  40  can be conducted to the heat conducting element  20  through the mounting plate  30 , and then the heat can be dissipated to the outside. Besides, as shown in  FIG. 5 , the LED lamp further includes a transparent cover  50 , a transformer  60  for supplying power to the LED module  40  and a base  70  connected to the bottom of the heat dissipation assembly  10 . 
     Referring to  FIGS. 1-3 , the hear dissipation assembly  10 , which is made by the aluminum die casting process, includes a cylinder  11 . A central hole  12  is provided in the center of the cylinder  10 . The central hole  12  tapers off from its opening to bottom to form two corresponding inclined surfaces  13 . Thus a tapered space is formed in the cylinder  11 . In particular, as can be seen in  FIG. 3 , thickness of the walls having the inclined surfaces  13  is uniform for providing an even effect of heat dissipation. 
     In this embodiment, a plurality of ribs  14  are provided on the outside of the cylinder  11  for adding surface area and increasing heat dissipation efficiency. Additionally, the outside of the cylinder  11  near the top is further provided with an annular groove  15  for being mounted by the transparent cover  50 . The bottom of the cylinder  11  connects to the base  70  by screwing or soldering connection as shown in  FIG. 4 . Thus the base  70  can be fixed in a lamp socket on a wall or ceiling. 
     The heat conducting element  20  is completely accommodated in the central hole  12 . The heat conducting element  20  includes a heat-absorbing section  21  and two heat-releasing sections  22  separately extending from the heat-absorbing section  21 . Both size and shape of the two heat-releasing sections correspond to the inclined surfaces  13  of the heat dissipation assembly  10  so that the heat-releasing sections  22  can contact the inclined surfaces  13 . In the shown embodiment, the heat conducting element  20  is an inverted-U shaped vapor chamber. Because a vapor chamber has a bigger interior space for accommodating more working fluid to make phase change, it can transfer more heat in a unit time. Besides, the vapor chamber having two heat-releasing sections can release heat simultaneously, and all heat contacting areas between the heat conducting element  20  and a heat generating source or the heat dissipation assembly  10  are directly planar contact, so its effect of heat transfer is much better than a heat pipe. 
     The heat-absorbing section  21  of the heat conducting element  20  is attached to the mounting plate  30  to form thermal contact. In this embodiment, the mounting plate  30  is of a shape of disk for matching the shape of the heat dissipation assembly  10 , and two indents  31  are provided at the edge of the mounting plate  30  for being passed through by wires  43 . 
     The LED module  40  includes a substrate  41 , a plurality of LEDs  42  mounted on the substrate  41  and the two wires  43  extending from the substrate  41 . The LED module  40  planarly connects to the mounting plate  30  to form thermal contact. The wires  43  of the LED module  40  pass through the indents  31  and then extend downwards. An inner surface of the heat dissipation assembly  10  is provided with two troughs  16  for accommodating the wires  43 . The wires  43  electrically connect to a circuit board  61  in the transformer  60 . In addition, the other wires  62  in the transformer  60  separately connect to two electrodes of the base  70  for obtaining power via the base  70 . By the arrangement of the troughs  16 , the wires  43  do not retard the thermal contact between the heat dissipation assembly  10  and heat conducting element  20 . 
     Referring to  FIG. 5 , the heat-absorbing section  21  of the heat conducting element  20  can also make thermal contact with the transformer  60 . In other word, the heat from the transformer  60  can be transferred to the heat dissipation assembly  10  by the heat conducting element  20 . 
       FIG. 6  shows another preferred embodiment of the invention. This embodiment retrenches the mounting plate  30  of the abovementioned embodiment. In this embodiment, the substrate  41  of the LED module  40  is enlarged enough to be placed on the opening of the central hole  12  of the heat dissipation assembly  10 . The substrate  41  is directly attached to the heat-absorbing section  21  of the heat conducting element  20  to form thermal contact. 
     It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention as defined by the appended claims.