Patent Publication Number: US-2010128484-A1

Title: Led heat dissipation structure

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to heat dissipation technology and more particularly, to a LED heat dissipation structure, which dissipates waste heat from light-emitting diode devices rapidly. 
     2. Description of the Related Art 
     Conventional lamps have the drawback of high power consumption and do not meet power-saving and environmental protection requirements. Nowadays, LED (light emitting diode) illumination technology has been intensively used to substitute for conventional lighting fixtures, thereby saving power consumption and improving environmental protection. However, LED has the drawback of high percentage, about 89˜90% energy loss of input power that generates waste heat. This waste heat must be quickly dissipated, avoiding lowering LED&#39;s luminous efficiency and working life. Therefore, it is important in the LED industry to find a measure to dissipate LED waste heat efficiently. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a LED heat dissipation structure, which eliminates accumulation of waste heat in the LED devices, improving the LED devices&#39; luminous efficiency and prolonging the LED devices&#39; working life. 
     To achieve this and other objects of the present invention, a LED heat dissipation structure comprises a heat sink having a base block and radiation fins, LED devices bonded to the flat top wall of the base block of the heat sink with a thermal compound, and a substrate affixed to the base block of the heat sink with screws to hold down the LED devices. The substrate has a circuit layer located on the bottom wall thereof and electrically connected with the LED devices to provide the necessary working power supply to the LED devices, and a plurality of through holes that accommodate epoxy lenses of the LED devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an oblique top elevation of a LED heat dissipation structure in accordance with the present invention. 
         FIG. 2  is an elevational, partially in section, of the LED heat dissipation structure in accordance with the present invention. 
         FIG. 3  is a sectional side view of the LED heat dissipation structure in accordance with the present invention. 
         FIG. 4  is a perspective view of an alternate form of the present invention. 
         FIG. 5  is a perspective view of another alternate from of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1˜3 , a LED heat dissipation structure in accordance with the present invention is shown comprising a heat sink  1 , a substrate  2  and LED (light emitting diode) devices  3 . 
     The heat sink  1  is prepared from a high thermal conductivity metal material, having a base block  11 , a plurality of radiation fins  12  radially extended from the periphery of the flat base block  11  and a plurality of screw holes  111  located on the flat top wall of the base block  11 . The base block  11  may be prepared in any of a variety of shapes. According to this embodiment, the base block  11  has a rectangular configuration. 
     The substrate  2  has a circuit layer (not shown) arranged on the bottom wall thereof, a plurality of through holes  21  cut through the top and bottom walls at selected locations and a plurality of mounting holes  22  corresponding to the screw holes  111  of the heat sink  1 . 
     The LED devices  3  each comprise a body  31 , an epoxy lens  32  covering the top side of the body  31  through which light emitted by the light emitting chip(s) (not shown) in the body  31  passes to the outside and positive pole and negative pole lead wires  33  bilaterally extended out of the body  31 . 
     During installation, a thermal compound  4  is applied to the flat top wall of the base block  11  of the heat sink  1  corresponding to the locations for the LED devices  3 , and then the prepared LED devices  3  (the number of the LED devices  3  is equal to the number of the through holes  21  of the substrate  2 ) are respectively positioned on the applied thermal compound  4  at the flat top wall of the base block  11  of the heat sink  1  to keep the bottom wall of the body  31  of each LED  3  in positive contact with the applied thermal compound  4 , and then the substrate  2  is covered on the LED devices  3  over the flat top wall of the base block  11  of the heat sink  1  to have the epoxy lenses  32  of the LED devices  3  be inserted into the through holes  21  of the substrate  2  and the peripheral edge of each through hole  21  be abutted against the surface of the body  31  of the associating LED device  3 , and then the positive pole and negative pole lead wires  33  of the LED devices  3  are respectively bonded to respective contacts at the circuit layer of the substrate  2 . Thereafter, tie screws  5  are respectively mounted in the mounting holes  22  of the substrate  2  and threaded into the screw holes  111  of the heat sink  1  to affix the substrate  2  to the heat sink  1  and to have the LED devices  3  be secured firmly between the heat sink  1  and the substrate  2 . The thermal compound  4  fills up the gap between the body  31  of each LED  3  and the base block  11  of the heat sink  1 , assuring quick and efficient transfer of waste heat from the LED devices  3  to the heat sink  1  for quick dissipation into the outside open air through the radiation fins  12 . 
     During operation of the present invention, the necessary power supply is transmitted by the circuit layer of the substrate  2  to the LED devices  3 , causing the LED devices  3  to emit light. During operation of the LED devices  3 , waste heat produced by the LED devices  3  is transferred from the bottom side of the body  31  of each LED device  3  through the applied thermal compound  4  to the base block  11  of the heat sink  1  and then the radiation fins  12  for dissipation into the outside open air. Because the invention uses the substrate  2  to hold down the LED devices  3  on the heat sink  1 , the bodies  31  of the LED devices  3  are kept in direct contact with the heat sink  1  for quick transfer of waste heat to the heat sink  1  during operation, therefore the invention prevents accumulation of waste heat in the LED devices  3 , improving the luminous efficiency of the LED devices  3  and prolonging their working life. 
     Further, the substrate  2  can be an aluminum substrate or metal-composite substrate that absorbs and dissipates waste heat from the LED devices  3 , enhancing heat dissipation. 
     Further, each LED device  3  can be a single-piece light emitting diode, or a LED module.  FIG. 4  shows an alternate form of the present invention. According to this embodiment, each LED device  3  comprises multiple epoxy lenses  32  located on the top side of the body  31  thereof corresponding to respective LED chips (not shown) in the body  31 . 
       FIG. 5  shows another alternate form of the present invention. According to this embodiment, each LED device  3  comprises a plurality of power contacts  34  located on the top side of the body  31  outside the epoxy lens  32  for bonding to the respective contacts at the circuit layer of the substrate  2 . 
     Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.