Light emitting diode package with metal reflective layer and method of manufacturing the same

Abstract

The invention relates to an LED package having a metal reflective layer for focusing and emitting light through a side of the package, and a manufacturing method of the same. The LED package includes a substrate with an electrode formed thereon, a light emitting diode chip disposed on the substrate, and an encapsulant covering the LED chip and the substrate to protect the LED chip. The LED package also includes a metal reflective layer surrounding side surfaces of the encapsulant to form a light transmitting surface on a top surface of the encapsulant. The invention minimizes light loss, improves luminance, can be mass-produced as a PCB type, and adopts EMC transfer molding to minimize irregular color distribution, thereby improving optical quality.

1 . A light emitting diode package for emitting light from a light emitting diode chip in one direction, comprising: 
 a substrate with an electrode formed thereon;    a light emitting diode chip disposed on the substrate;    an encapsulant covering the LED chip and the substrate to protect the LED chip; and    a metal reflective layer surrounding side surfaces of the encapsulant to form a light transmitting surface on a top surface of the encapsulant.    
   
   
       2 . The light emitting diode package according to  claim 1 , wherein the metal reflective layer is formed by depositing or plating metal selected from a group consisting of Al, Au, Ag, Ni, W, Ti and Pt.  
   
   
       3 . The light emitting diode package according to  claim 1 , wherein the substrate comprises a printed circuit board or a ceramic substrate with an electrode formed thereon.  
   
   
       4 . The light emitting diode package according to  claim 1 , wherein the light transmitting surface is disposed in front and in parallel with a plane where the light emitting diode chip is disposed.  
   
   
       5 . The light emitting diode package according to  claim 1 , wherein the encapsulant is made of epoxy molding compound with phosphor mixed and uniformly dispersed therein.  
   
   
       6 . A method of manufacturing a light emitting diode package for emitting light from a light emitting diode chip in one direction, comprising steps of: 
 providing a substrate with an electrode formed thereon;    disposing a light emitting diode chip on the substrate;    forming an encapsulant on the light emitting diode chip and the substrate;    cutting the encapsulant; and    forming a reflective layer on the encapsulant.    
   
   
       7 . The method according to  claim 6 , wherein the step of forming an encapsulant comprises Epoxy Molding Compound (EMC) transfer molding of transparent epoxy molding compound with phosphor mixed therein.  
   
   
       8 . The method according to  claim 6 , wherein the step of cutting the encapsulant comprises dicing or etching only the encapsulant to obtain a desired form of encapsulant for the light emitting diode chip, and exposing a pattern electrode plated on the substrate.  
   
   
       9 . The method according to  claim 6 , wherein the step of forming a reflective layer comprises depositing or plating metal selected from a group consisting of Al, Au, Ag, Ni, W, Ti and Pt.  
   
   
       10 . The method according to  claim 6 , wherein the step of forming a reflective layer comprises forming a sputtered layer made of highly reflective metal around an outer surface of the encapsulant via vacuum sputtering, and removing a portion of the sputtered layer via polishing, thereby forming a light transmitting surface.  
   
   
       11 . The method according to  claim 6 , wherein the step of forming a reflective layer includes cutting the plated reflective layer and the substrate or the sputtered reflective layer and the substrate into individual light emitting diode packages.  
   
   
       12 . The method according to  claim 7 , wherein the EMC transfer molding for forming an encapsulant comprises inserting the substrate and the light emitting diode chip in a mold maintained at a temperature ranging from 150° C. to 190° C., inserting a solid mixture of transparent epoxy molding compound and phosphor maintained at a temperature ranging from 80° C. to 90° C. into the mold, thereby changing a phase of the mixture of transparent EMC and phosphor from solid to liquid to form an encapsulant.  
   
   
       13 . The method according to  claim 12 , further comprising a step of compressing the solid mixture of transparent epoxy molding compound and phosphor into the mold at 500 psi to 1000 psi.  
   
   
       14 . The method according to  claim 13 , wherein the mixture is cured into the encapsulant without precipitation of the phosphor in the transparent epoxy molding compound in order to minimize irregular color distribution.