Method for coating phosphor, apparatus to perform the method, and light emitting diode comprising phosphor coating layer

Abstract

A method of forming a phosphor coating layer on a light emitting diode (LED) chip using electrophoresis includes separating phosphor particles in a suspension according to a particle size, and coating the phosphor particles on a surface of the LED chip by sequentially depositing the separated phosphor particles on the surface of the LED chip according to the particle size. An apparatus to form a phosphor coating layer on an LED chip includes an electrophoresis bath to accommodate a suspension containing phosphor particles separated into layers according to a particle size, and electrodes disposed inside the electrophoresis bath. The electrodes may include a cathode electrode on which the LED chip may be arranged, and an anode electrode.

What is claimed is: 
     
         1 . A light-emitting diode (LED) comprising:
 a phosphor coating layer arranged on a surface of an LED chip, the phosphor coating layer comprising:
 first phosphor particles arranged on the surface of the LED chip; and 
 second phosphor particles comprising a smaller size than a size of the first phosphor particles and arranged on the first phosphor particles and the surface of the LED chip, 
   wherein the second phosphor particles fill gaps between the first phosphor particles so that at least one of the first phosphor particles contacts at least one of the second phosphor particles, and   wherein at least one of the second phosphor particles is disposed directly between at least one of the first phosphor particles and the surface of the LED chip in a direction substantially perpendicular to the surface of the LED chip.   
     
     
         2 . The LED of  claim 1 , wherein the first phosphor particles comprise a different kind of phosphor than the second phosphor particles. 
     
     
         3 . The LED of  claim 2 , wherein a combination of the first phosphor particles and the second phosphor particles are continuously arranged across the surface of the LED chip. 
     
     
         4 . The LED of  claim 3 , wherein the first phosphor particles and the second phosphor particles are mixed together vertically and horizontally. 
     
     
         5 . A light-emitting diode (LED) comprising:
 a phosphor coating layer arranged on a surface of an LED chip, the phosphor coating layer comprising:
 first phosphor particles arranged on the surface of the LED chip; and 
 second phosphor particles comprising a smaller size than a size of the first phosphor particles and arranged on the first phosphor particles and the surface of the LED chip, 
   wherein the second phosphor particles fill gaps between the first phosphor particles,   wherein at least one of the second phosphor particles is disposed directly between at least one of the first phosphor particles and the surface of the LED chip in a direction substantially perpendicular to the surface of the LED chip, and   wherein a combination of the first phosphor particles and the second phosphor particles are continuously disposed directly on the surface of the LED chip.   
     
     
         6 . The LED of  claim 5 , wherein the first phosphor particles comprise a different kind of phosphor than the second phosphor particles. 
     
     
         7 . The LED of  claim 6 , wherein the first phosphor particles and the second phosphor particles are mixed together vertically and horizontally. 
     
     
         8 . A light-emitting diode (LED) comprising:
 a phosphor coating layer arranged on a surface of an LED chip, the phosphor coating layer comprising:
 first phosphor particles continuously arranged across the surface of the LED chip; and 
 second phosphor particles comprising a smaller size than a size of the first phosphor particles and continuously arranged across the surface of the LED chip, wherein the second phosphor particles fill gaps between the first phosphor particles. 
   
     
     
         9 . The LED of  claim 8 , wherein the first phosphor particles comprise a different kind of phosphor than the second phosphor particles. 
     
     
         10 . The LED of  claim 9 , wherein the first phosphor particles and the second phosphor particles are mixed together vertically and horizontally.