Light emitting device and fabrication method thereof

Abstract

A light emitting device fabrication method. The fabrication method of the light emitting device comprises providing a light emitting semiconductor device; positioning a plurality of luminescent particles at the optical path of the light emitting semiconductor device; and reducing the distance between the luminescent particles to enhance the molecular attraction between the luminescent particles, than the luminescent particles is coagulated to a luminescent powder layer by the molecular attraction.

1 . A light emitting device, comprising:
 a light emitting semiconductor device; and   a luminescent powder layer which is adhesive material free, disposed on an optical path of the light emitting semiconductor device, wherein at least a part of the luminescent powder layer is coagulated.   
     
     
         2 . The light emitting device as claimed in  claim 1 , wherein the luminescent powder layer comprises a plurality of luminescent particles, and the luminescent particles are coagulated by attraction of molecular interaction. 
     
     
         3 . The light emitting device as claimed in  claim 1 , wherein the luminescent particles comprise powder phosphors. 
     
     
         4 . The light emitting device as claimed in  claim 2 , wherein the luminescent powder layer is adhered to the light emitting semiconductor device. 
     
     
         5 . A light emitting device fabrication method, comprising:
 dispersing a plurality of luminescent particles in a liquid to form a mixture, wherein the liquid is adhesive material free;   positioning a substrate into the mixture for a period of time such that the luminescent particles precipitate on the substrate; and   removing the liquid to coagulate the luminescent particles as a luminescent powder layer adhering to the substrate.   
     
     
         6 . The light emitting device fabrication method as claimed in  claim 5 , wherein the liquid comprise water or volatile solvent, which are free of epoxy resin and glue. 
     
     
         7 . The light emitting device fabrication method as claimed in  claim 6 , wherein the volatile solvent comprises ethers, alcohols, ketones or combinations thereof. 
     
     
         8 . The light emitting device fabrication method as claimed in  claim 5 , wherein the liquid is removed by a baking step, the baking step controlled at a temperature such that a perturbation of the liquid caused by the baking does not affect the arrangement of the luminescent particles on the substrate. 
     
     
         9 . The light emitting device fabrication method as claimed in  claim 5 , wherein the method further comprises:
 forming a first passivation layer at least cover a top surface of the luminescent powder layer; and   forming a second passivation layer at least cover the first passivation layer and the substrate.   
     
     
         10 . The light emitting device fabrication method as claimed in  claim 5 , wherein the substrate comprises a light emitting diode. 
     
     
         11 . A fabrication system of the light emitting device, comprising:
 a container;   a disposal device for disposing a substrate to the container;   a liquid supply device for injecting a liquid into the container to a level higher than the substrate, wherein the liquid is free of adhesive;   a stirring device for uniformly dispersing a plurality of the luminescent particles in the liquid to form a mixture; and   a liquid removing device for removing the liquid after the luminescent particles precipitate on the substrate, thereby coagulating the luminescent particles adhering to the substrate.