Led device

Abstract

An LED device comprises a substrate, an LED chip and a luminescent conversion layer. The substrate comprises a first electrode, a second electrode and a reflector located on top faces of the first and the second electrodes. The LED chip is disposed on the first electrode and electrically connected to the first and the second electrodes. The luminescent conversion layer is located inside the reflector and comprises a first luminescent conversion layer and a second luminescent conversion layer with different specific gravities.

What is claimed is: 
     
         1 . An LED (light emitting diode) device, comprising:
 a substrate, comprising a first electrode, a second electrode and a reflector located on top faces of the first and the second electrodes;   an LED chip, located on the first electrode inside the reflector and electrically connecting to the first and the second electrodes, comprising positive light within an angle range; and   a luminescent conversion layer, located inside the reflector and covering the LED chip, comprising a first luminescent conversion layer and a second luminescent conversion layer with different specific gravities;   wherein the first luminescent conversion layer corresponds to the LED chip and the second luminescent conversion layer surrounds the first luminescent conversion layer.   
     
     
         2 . The LED device as claimed in  claim 1 , wherein the first luminescent conversion layer is a cylinder covering the LED chip. 
     
     
         3 . The LED device as claimed in  claim 2 , wherein the first luminescent conversion layer meets the following condition: 
       
         
           
             
               D 
               = 
               
                 [ 
                 
                   
                     2 
                     × 
                     
                       ( 
                       
                         tan 
                          
                         
                             
                         
                          
                         
                           θ 
                           · 
                           H 
                         
                       
                       ) 
                     
                   
                   + 
                   d 
                 
                 ] 
               
             
           
         
         
           
             
               θ 
               = 
               
                 
                   ( 
                   
                     180 
                     - 
                     ψ 
                   
                   ) 
                 
                 2 
               
             
           
         
         wherein D is a diameter of the cylinder, θ is an angle of laterally-emitting light of the LED chip, H is a depth of the cylinder, d is a width of the LED chip and ψ is an angle of the positive light from the LED chip. 
       
     
     
         4 . The LED device as claimed in  claim 3 , wherein the angle of the positive light ψ is between 100˜130 degrees. 
     
     
         5 . The LED device as claimed in  claim 1 , wherein the reflector is made of polymer, polyphthalamide (PPA) or plastic.