Patent Publication Number: US-2007096136-A1

Title: Cladding layer structure of a LED package structure

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to the LED (light emitting diode) field, and more particularly to a cladding layer structure of a LED package structure.  
      2. Description of the Prior Art  
      In the LED (light emitting diode) technology, LED chip is adapted to generate light by cooperating with optical elements. As shown in  FIG. 1 , a conventional LED package structure is illustrated and comprises a substrate  10 , a conductive layer  11 , a chip  12 , a welding wire  13 , a sealing resin  14  and an optical lens  15 .  
      The conductive layer  11  is placed on the substrate  10  and is in electrical contact with both sides of the substrate  10 . The chip  12  is placed one side of the substrate  10  and is connected to the conductive layer  11  by the welding wire  13 , for electrically connecting the chip  12  with outside. The sealing resin  14  is coated on the substrate  10  for covering the chip  12 , the welding wire  13 , and a part of the conductive layer  11 . The optical lens  15  is placed on the sealing resin  14  and includes a concave surface  151  and a convex surface  152 , and the concave surface faces the sealing resin  14 .  
      However, in this conventional LED package structure, the chip is directly adhered in the cup by adhesive agent, and then is sealed with sealing resin. In application, it must use extra circuit to connect the respective LED together, the resultant disadvantage is that the illumination area is too small, which will cause shadow and faculae.  
      The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.  
     SUMMARY OF THE INVENTION  
      The primary objective of the present invention is to provide a cladding layer structure of a LED package structure that have the same luminance as the incandescent lamp or the Fluorescent Lamp.  
      The primary objective of the present invention is to provide a cladding layer structure of a LED package structure, wherein a cladding layer is provided on the substrate, so as to improve the light generating efficiency of the chip.  
      The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiments in accordance with the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  shows a conventional LED package structure;  
       FIG. 2  is a perspective view of showing a cladding layer in accordance with a first embodiment of the present invention;  
       FIG. 3  is a cross sectional view of a LED package structure with the cladding layer of  FIG. 2 ;  
       FIG. 4  is a perspective view of showing a cladding layer in accordance with a second embodiment of the present invention;  
       FIG. 5  is a cross sectional view of a LED package structure with the cladding layer of  FIG. 2 ;  
       FIG. 6  is a perspective view of showing the cladding layer in accordance with a third embodiment of the present invention; and  
       FIG. 7  is a cross sectional view of showing the sealing structure for a white light LED in accordance with the third embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring to  FIGS. 2 and 3 , a cladding layer structure of a LED (light emitting diode) package structure in accordance with the present invention comprises: a base  2 , a chip  22 , a welding wire  23 , a cladding layer  24 , a resin  25  and an optical lens  26 . A printed circuit layer  21  with an electrode-welding pad  211  is placed on the substrate  20  of the base  2 , the chip  22  is located on the surface of the printed circuit layer  21 , and the cladding layer  24  having a through hole  241 : is also arranged on the printed circuit layer  21 . The chip  22  is received in the through hole  241  of the cladding layer  24 . The welding wire  23  has one end connected to the chip  22  and another end connected to the electrode welding pad  211  of the printed circuit layer  22 . The resin  25  is filled in the through hole  241  to seal the chip  22  and the welding wire  23 . The optical lens  26  is larger than the through hole  241  and is mounted on the surface of the cladding layer  24 .  
      The sealing structure for a white light LED (light emitting diode) in accordance with this embodiment utilizes the through hole of the cladding layer to receive the chip.  
      Besides, a plurality of chips are received in the through holes of the cladding layer, and the sidewall of the whole cladding layer is utilized to improve the light generating efficiency of the chip.  
      Referring to  FIGS. 4 and 5 ,  FIG. 4  is a perspective view of showing a cladding layer in accordance with a second embodiment of the present invention, and  FIG. 5  is a cross sectional view of a LED package structure with the cladding layer of  FIG. 4 . This embodiment is slightly different from the previous embodiment shown in  FIGS. 2 and 3 , and the differences are described below:  
      Referring firstly to  FIG. 4 , a recess  441  is formed in the cladding layer  44 , and the recess  341  has a flat bottom  4411 . Six through holes  4421 A,  4421 B,  4421 C,  4421 D,  4421 E and  4421 F are arranged in line and defined in the center of the bottom  4411  of the recess  441 . An elongated through hole  4422 A,  4422 B is defined at either side of the line of the through holes  4421 A,  4421 B,  4421 C,  4421 D,  4421 E and  4421 F.  
      The through holes  4422 A and  4422 B are adapted to receive the electrode welding pads  411 A and  411 B the printed circuit layer  41 , and the electrode welding pads  411 A and  411 B will protrude out of the through holes  4422 A and  4422 B when the cladding layer  44  is placed on the printed circuit layer  41 .  
      As shown in  FIG. 5 , the difference of this embodiment with respect to the first embodiment as shown in  FIG. 3  is the structure and the arrangement of the cladding layer  44  and the chip  42 .  
      In this embodiment, the cladding layer  44  is located on the printed circuit layer  41  in such a manner that the electrode welding pads  411 A and  411 B protrude out of the through holes  4422 A and  4422 B. The chip  42  is received in the through hole  4421 A. The welding wires  43 A and  43 B each has one end connected to the chip  42  and another end connected to the electrode welding pads  411 A and  411 B on the printed circuit layer  41  via the through holes  4422 A and  4422 B.  
      The resin  45  is filled in the recess  441  and the respective through holes  4421 A,  4422 A and  4422 B to seal the chip  42 , the electrode welding pads  411 A and  411 B, and the welding wires  43 A and  43 B. And an optical lens  46  is placed on the cladding layer  44 .  
      The through hole  4421 A in this embodiment is described above for purposes of example only, and in fact, each of the through holes  4421 A,  4421 B,  4421 C,  4421 D,  4421 E and  4421 F is received with a chip  42 , and each chip  42  is provided with a welding wire  43 A and  43 B.  
      Referring then to  FIGS. 6 and 7 ,  FIG. 6  is a perspective view of showing the cladding layer in accordance with a third embodiment of the present invention, and  FIG. 7  is a cross sectional view of showing the sealing structure for a white light LED in accordance with the third embodiment of the present invention. This embodiment is slightly different from the first embodiment, and the differences are described as follows:  
      As shown in  FIG. 6 , a first recess  641  with a predetermined depth is defined in the surface of the cladding layer  64 , and a second recess  642  smaller than first recess  641  is formed in the bottom  6411  of the first recess  642 . Four through holes  6431 A,  6431 B,  6431 C and  6431 D are arranged in line and defined in the center of the bottom  6421  of the second recess  642 . A rectangular through hole  6432 A and  6432 B is defined at either side of the line of the through holes  6431 A,  6431 B,  6431 C and  6431 D.  
      As shown in  FIG. 7 , two electrode welding pads  611 A and  611 B are arranged on the surface of the printed circuit layer  61  and are located correspondingly to the rectangular through holes  6432 A and  6432 B, and the electrode welding pads  611 A and  611 B will protrude out of the through holes  6432 A and  6432 B when the cladding layer  64  is placed on the surface  61  of the printed circuit  602 .  
      The chip  62  is positioned in the through hole  6431 A and is connected to the electrode welding pads  611 A and  611 B by the welding wires  63 A and  63 B, respectively. The resin  65  is filled in the second recess  642  and the through holes  6431 A,  6431 B,  6431 C and  6431 D, so as to seal the bottom  642 , the welding wires  63 A and  63 B, and the chip  62 . And then an optical lens  66  larger than the first recess  641  is placed on the cladding layer, thus forming a LED package structure.  
      According to the abovementioned cladding layer structure of the LED package structure, the cladding layer having through holes are located on the base, and the chips are received in the through holes. By such arraignments, a single LED structure has a plurality of light emitting chips, and it will have the same luminance as the incandescent lamp or the Fluorescent Lamp. Furthermore, the through holes in the cladding layer are used for holding the chips, thus improving stability.  
      In addition, the inner wall of the through holes for holding the chips can be inclined, so that the light generated by the chips will be reflected, and thus the luminance of the chips will be improved to the same level as the incandescent lamp or the Fluorescent Lamp.  
      While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.