Patent Publication Number: US-2006012298-A1

Title: LED chip capping construction

Description:
BACKGROUND OF THE INVENTION  
      (a) Field of the Invention  
      The present invention is related to an LED chip capping technology, and more particularly, to one that effectively eliminate diaphragm of strange color.  
      (b) Description of the Prior Art  
      As illustrated in  FIG. 1  of the accompanying drawings for a schematic view of a construction of a light emitting diode (LED) providing specific light color effects by having the light emission from the chip incorporated with wave length of fluorescent material, the LED relates to a packaging containing conductors  10  of different polarities and a carrier  20 . The carrier  20  is fixed with a chip  30  and a fluorescent material  40  while an electrode layer  31  of the chip  30  and the conductors  10  are connected by means of a golden plated wire  50 .  
      Once the conductors  10  are conducted, light emitted from the chip  30  passing through the fluorescent material  40  is incorporated with the wavelength of the fluorescent material  40  to create a specific light color. For example, the white light LED of the prior art has its chip to emit blue light through yellow fluorescent material to provide white light effects. Whereas the LED of the prior art as illustrated in  FIG. 1 , the space above the chip  30  is not capped by the fluorescent material; the light emitted straight up from the chip  30  is not subject to the incorporation of wavelength with the fluorescent material as those lights reflected from the peripheral of the chip  30  and is vulnerable to create significant diaphragm of strange color.  
      An improvement is made by having capping the surface of the chip  30  a comparatively thick while insulation glue in the hope to mitigate the diaphragm of strange color by taking advantage of the light transmission of the white insulation glue. However, the phenomenon of diaphragm of strange color still presents though at a lesser degree. Furthermore, the capping on the chip with the white insulation glue also reduces the luminance of the LED.  
     SUMMARY OF THE INVENTION  
      The primary purpose of the present invention is to provide a chip capping construction for a light emitting diode that effectively inhibit the creation of diaphragm of strange color. To achieve the purpose, additional to the basic construction of having fixed a chip and a fluorescent material to the carrier of the LED and a golden plated wire to connect the electrode layer of the chip and the conductors, a transparent transition layer is capped on the top of the chip, and a functional layer mixed with fluorescent material is further capped on the transition layer. The thickness of the functional layer at where in relation to the top layer of the chip is greater than that in relation to the peripheral of the chip so that the convex functional layer balances the incorporation of wavelength of the lights on the top layer of the chip and on the peripheral of the chip respectively with that of the fluorescent material. Of course, another convex light penetration layer may further cap on the functional layer to provide proper protection for the functional layer, the transitional layer and the chip. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic view of a construction of a light emitting diode of the prior art.  
       FIG. 2  is a schematic view of a construction of a light emitting diode of a first preferred embodiment of the present invention.  
       FIG. 3  is a schematic view showing a magnified construction of the capping layer of the LED of the present invention.  
       FIG. 4  is a schematic view of a construction of a light emitting diode of a second preferred embodiment of the present invention.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring to  FIG. 2  for a basic construction of a light emitting diode of the present invention, a packaging  70  contains multiple conductors  10  of different polarities and a carrier  20 . The packaging  70  is made of epoxy or a transparent material. A chip  30  and a fluorescent material  40  are placed in the carrier. A golden plated wire  50  connects an electrode layer  31  of the chip  30  and those conductors  10 . Accordingly, once those conductors  10  are conducted, the light emitted form the chip  30  passing through the fluorescent material is incorporated with the wavelength of the fluorescent material  40  to form a specific light color. Also as illustrated in  FIG. 3 , the top of the chip  30  is capped with a transparent transitional layer  62 . The top of the transparent transition layer  62  is capped with a functional layer  63  mixed with fluorescent material  40 . In the preferred embodiment, the transparent transition layer  62  is related to a convex structure of hardened transparent insulation glue; and the functional layer  63  is related to an admixture of powders of fluorescent material  40  and epoxy also hardened into a convex structure. The top of the functional  63  may be further capped with another hardened, convex layer  64  pervious to light of the same transparent insulation glue to protect the chip and avoid creating the phenomenon of diaphragm of strange color.  
      The present invention is essentially characterized by that the thickness of the capping layer at where the functional layer  63  is in relation to the top layer of the chip  30  is greater than that of the functional layer  63  in relation to the peripheral of the chip  30 . Accordingly, the convex functional layer  63  balances the wavelength incorporation of the fluorescent material  40  respectively with the top and the peripheral of the chip  30  to effectively inhibit the creation of the diaphragm of strange color.  
      In the preferred embodiment as illustrated in  FIGS. 2 and 3 , the carrier is disposed at the bowl structure on the conductors  10  and the bottom of the chip  30  is separately provided with the fluorescent material  40 . The fluorescent material  40  provided at the bottom of the chip  30  is related to an admixture of fluorescent powders and the adhesive agent used to fix the chip  30 . Therefore, the fluorescent material  40  can be coated at the base layer of the carrier  20  with the bottom of the chip  30  buried into the fluorescent material for a certain section to fix both of the chip  30  and the carrier  20  in place.  
      Now referring to  FIG. 4  for a second preferred embodiment of the present invention, the LED is directly constructed on a circuit plate  80 . The carrier  20  preset with a recess is provided on the circuit board  80 . Each conductor (not illustrated) is directly laid on the circuit contact of the circuit board  80 . The fluorescent material  40 , the chip  20 , the transitional layer, the functional layer and the light permeable layer are constructed in sequence in the recessed carrier  20  to become the LED on the circuit board  80 .  
      The present invention for providing an improved capping structure for the chip in an LED, this application for a utility patent is duly filed accordingly. However, it is to be noted that that those preferred embodiments disclosed in the specification and the accompanying drawings are in no way limiting the present invention. Therefore, any construction, installation, or characteristics that is same or similar to that of the present invention should fall within the scope of the purposes and claims of the present invention.