Patent Publication Number: US-2012038261-A1

Title: Heat-dissipating structure and lighting module having the same

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates to a heat-dissipating structure of a lighting module; in particular, a heat-dissipating structure with a main body having external surfaces and heat pipes and a lighting module having the same. 
     2. Description of the Related Art 
     As technology advances in favor of more energy-efficient lighting devices, the conventional incandescent light bulbs are gradually being replaced by light-emitting diodes (LEDs). 
     LEDs possess many advantages over the traditional incandescent light sources including lower energy consumption, longer lifetime, improved robustness, smaller size, faster switching, and greater durability and reliability. Thus, intense research is being conducted in the area of LEDs development. However, like other lighting devices, the performance of LED is temperature dependent. For example, if the junction temperature or the temperature of the semiconducting material is too high due to heat escalation, loss of efficiency would occur. Therefore, proper thermal management of the LED device is required to maintain optimal lighting performance. 
     To improve heat dissipation capacity, a current technique is to dispose LEDs onto an external heat sink. However, such setup is not adequate enough to dissipate heat effectively. 
     To address the above issue, the inventor proposes the following solution. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a heat-dissipating structure for lighting modules. 
     Another object of the present invention is to provide a lighting module having the heat-dissipating structure to maintain the lighting performance. 
     To achieve the primary object, the instant disclosure provides a heat-dissipating structure having a main body with a plurality of external surfaces; at least one heat pipe connecting to the main body, wherein each heat pipe has a hot end and a cold end, with the hot end being embedded in the main body and the cold end extending to expose from an external surface to define a contacting surface; and at least one external heat sink connecting to the contacting surface. 
     To achieve the other object, the instant disclosure provides a lighting module having said heat-dissipating structure and at least one light source disposed on the main body. 
     The instant disclosure presents the following advantages. First, the main body and each heat pipe are formed integrally in one piece. Second, when applied to the lighting module, said heat-dissipating structure can efficiently dissipate heat generated by each light source to prevent overheating. 
     In order to further appreciate the characteristics and technical contents of the instant disclosure, references are hereunder made to the detailed descriptions and appended drawings in connection with the instant disclosure. 
     However, the appended drawings are merely shown for exemplary purposes, rather than being used to restrict the scope of the instant disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is an isometric view of a heat-dissipating structure of lighting for a first embodiment. 
         FIG. 1B  is a schematic view of a heat-dissipating structure of lighting for a first embodiment. 
         FIG. 2A  is an isometric view of a heat-dissipating structure of lighting for a second embodiment. 
         FIG. 2B  is a side view of a heat-dissipating structure of lighting for a second embodiment. 
         FIG. 2C  is a schematic view of a heat-dissipating structure securing to an external heat sink of a second embodiment. 
         FIG. 2D  is a schematic view of an external heat sink. 
         FIG. 3  is a schematic view of a lighting module. 
         FIG. 4  is a schematic view of a light source securing to a heat-dissipating structure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The instant disclosure provides a heat-dissipating structure for lighting to increase the thermal management performance. 
       FIG. 1A  shows a first embodiment of the instant disclosure. The heat-dissipating structure comprises a main body  10  thermally coupled to a heat pipe  11 . The main body  10  has a plurality of external surfaces, such as top surface (not labeled), side surfaces  100  and a bottom surface  102 . Specifically, the main body  10  comprises a plurality of polygonal external surfaces to increase external surface area, thereby maximizing the heat dissipating capabilities of the lighting module. Moreover, each side surface  100  may form a fixing area  101 , which can have a flat, stepped or curved surface, or any other surface configuration for hosting a light source device, an electronic device, or being used for light reflecting purposes. As shown in  FIG. 3 , each fixing area  101  can further form a slot  103  to ensure the light source or electronic device, such as a light-emitting diode  20 , is firmly mounted. The slot  103  is not restricted in size, shape, and quantity. 
     Referring back to  FIG. 1A , the heat pipe  11  has a hot end  111  embedded in the main body  10  and a cold end  112  forming a contacting surface  113 . To maximize the heat transfer area, the heat pipe  11  has at least one bent surface. For example, the hot end  111  is bended from a vertical position and extended annularly in forming the cold end  112 . In the first embodiment, the contacting surface  113  of the cold end  112  is flushed with the bottom surface  102  of the main body  10 . Alternatively, as shown in  FIGS. 2A and 2B , the cold end  112  can be seated outside of the main body  10 . 
     To provide better heat transfer, the pre-fabricated heat pipe  11  is sintered to the main body  10  in forming a single unit. In other words, the heat pipe  11  is thermally coupled to the main body  10 , for example, the heat pipe  11  is physically contact the main body  10 . Meanwhile, the main body  10  is made using material of high thermal conductivity, such as aluminum, copper, ceramics, or graphite. 
     As shown in  FIG. 1B , the flushed contacting surface  113  is then secured onto an external heat sink  30 . The external heat sink  30  has a receiving surface  301  for mating to the bottom surface  102  and the contacting surface  113 . Thus, heat released by the cold end  112  can be dissipated via the external heat sink  30 . 
     On the other hand, where the cold end  112  is seated outside the main body  10 , the contacting surface  113  is mated to an external heat sink  30  as follows. A receiving portion  302  is formed on the receiving surface  301  of the external heat sink  30  for connecting with the contacting surface  113 . As shown in  FIGS. 2C and 2D , the receiving portion  302  can be a groove for mating to the cold end  112 . Adhesives or sintering process can be used to connect the receiving portion  302  and contacting surface  113 , further to ensure the external heat sink  30  is firmly secured. 
     Thereby, the heat generated by the light source or electronic device is passed onto the main body  10 . The embedded hot end  111  of the heat pipe  11  absorbs the heat from the main body  10  and releases the latent heat at the cold end  112  to the external heat sink  30  for heat dissipation. 
     As shown in  FIG. 4 , the instant disclosure further provides a lighting module having a light source and said heat-dissipating structure. The light source, such as a light-emitting diode  20 , is disposed on the main body  10  of the heat-dissipating structure. In particular, an adhesive layer  21  with high thermal conductivity can be used to fix the light-emitting diode  20  onto the slot  103  of the main body  10 . The slot  103  is shaped to reflect the light generated by the light source. Electrically connected to conductive blocks  22 , the light-emitting diode  20  can be of different types and colors. Furthermore, the lighting module can be placed into a light bulb as a LED lamp. 
     In summary, the instant disclosure presents the following advantages. First, the heat pipe of the heat-dissipating structure transfers heat more effectively to the external heat sink versus the light source alone. Secondly, the lighting module having said heat-dissipating structure has better thermal management, which allows the lighting module to have longer service life and better lighting quality. 
     The descriptions illustrated supra set forth simply the preferred embodiments of the instant disclosure; however, the characteristics of the instant disclosure are by no means restricted thereto. All changes, alternations, or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the instant disclosure delineated by the following claims.