Producing a surface-mountable radiation emitting component

Abstract

A radiation-emitting surface-mountable component has a light-emitting diode chip mounted on a leadframe. A molding material encapsulates the leadframe and the light emitting diode chip.

1 . A method for producing a surface-mountable, radiation-emitting component, the method which comprises the following steps:
 mounting a radiation-emitting chip on a leadframe;   preparing a molding material from a resin powder prereacted with curing agent, and optionally added further fillers; and   encasing the leadframe and the radiation-emitting chip with the molding material.   
   
   
       2 . The method according to  claim 1 , wherein the step of preparing the molding material comprises:
 mixing a resin powder, prereacted with curing agent, with a conversion material and, optionally, further fillers; and   blending the mixture to provide a homogeneous powder mixture.   
   
   
       3 . The method according to  claim 2 , wherein the molding material is a plastics compression molding material. 
   
   
       4 . The method according to  claim 1 , which comprises encasing the radiation-emitting chip such that light exit sides of the chip are surrounded by the molding material. 
   
   
       5 . The method according to  claim 1 , wherein the prereacted resin powder consists of epoxy novolak or epoxy-cresol novolak. 
   
   
       6 . The method according to  claim 5 , which comprises utilizing epoxy resin prereacted with at least one of a phenol curing agent and an anhydride curing agent. 
   
   
       7 . The method according to  claim 1 , wherein the conversion material is a luminescent pigment powder containing at least one inorganic phosphor having a phosphor metal center M in a host lattice based on the general formula A 3 B 5 X 12 . 
   
   
       8 . The method according to  claim 7 , wherein the phosphor is YAG:Ce, TAG:Ce, TbYAG:Ce, GdYAG:Ce, GdTbYAG:Ce or a mixture formed therefrom. 
   
   
       9 . The method according to  claim 1 , wherein the conversion material is a luminescent pigment powder containing at a metal center M in a sulfide, oxysulfide, borate, aluminate or metal chelate complex. 
   
   
       10 . The method according to  claim 1 , which comprises pre-drying the luminescent pigment powder before mixing with the resin powder. 
   
   
       11 . The method according to  claim 1 , which comprises providing a resin initially in rod or tablet form, and milling the resin to provide the resin powder. 
   
   
       12 . The method according to  claim 1 , which comprises providing a resin initially in rod or tablet form and milling the resin, prior to mixing with the conversion material, to provide the resin powder. 
   
   
       13 . The method according to  claim 1 , which comprises mixing the resin powder or the resin and the conversion material, and optionally the further fillers, by first mixing the components coarsely and then milling the mixture in a mill to form a very fine, homogeneous powder. 
   
   
       14 . The method according to  claim 13 , which comprises milling the mixture in a ball mill. 
   
   
       15 . The method according to  claim 1 , which comprises milling the resin or the resin powder in a mill prior to mixing with the conversion material, and optional further fillers. 
   
   
       16 . The method according to  claim 15 , which comprises milling the resin or the resin powder in a coffee grinder. 
   
   
       17 . The method according to  claim 1 , which comprises mixing an adhesion promoter with the conversion material. 
   
   
       18 . The method according to  claim 1 , which comprises mixing an adhesion promoter with the resin powder. 
   
   
       19 . The method according to  claim 18 , which comprises mixing the adhesion promoter in liquid form with the conversion material. 
   
   
       20 . The method according to  claim 18 , wherein the adhesion promoter is one of glycidyloxy-propyltrimethoxysilane and further derivatives based on trialkoxysilane. 
   
   
       21 . The method according to  claim 1 , which comprises mixing a wetting agent with the conversion material, for improving a wettability of surfaces of the conversion material 
   
   
       22 . The method according to  claim 1 , which comprises adding at least one monofunctional and polyfunctional polar agent which has carboxyl, carboxylic ester, ether and alcohol groups and improves the wettability of the surfaces of the conversion material for modifying surfaces of the conversion material. 
   
   
       23 . The method according to  claim 1 , which comprises admixing a mold release agent or lubricant. 
   
   
       24 . The method according to  claim 23 , which comprises admixing the mold release agent or lubricant with the resin powder or prior to mixing with the conversion material. 
   
   
       25 . The method according to  claim 23 , wherein the mold release agent is a solid wax-based mold release agent or a metal soap with long-chain carboxylic acids. 
   
   
       26 . The method according to  claim 25 , wherein the mold release agent is a stearate. 
   
   
       27 . The method according to  claim 1 , which comprises admixing inorganic fillers for increasing a refractive index of the plastics compression molding material. 
   
   
       28 . The method according to  claim 27 , which comprises admixing fillers comprising oxides selected from the group consisting of TiO 2 , ZrO 2 , α-Al 2 O 3 , and other metal oxides. 
   
   
       29 . The method according to  claim 1 , which comprises mixing glass particles with the molding material as filler. 
   
   
       30 . The method according to  claim 29 , which comprises admixing glass particles having a mean particle size less than 100 μm. 
   
   
       31 . The method according to  claim 29 , which comprises admixing glass particles having a mean particle size less than 50 μm. 
   
   
       32 . The method according to  claim 29 , wherein a proportion of the glass particles in the molding material lies between 0% by weight and 90% by weight. 
   
   
       33 . The method according to  claim 29 , wherein a proportion of the glass particles in the molding material lies between 10% by weight and 50% by weight. 
   
   
       34 . The method according to  claim 1 , which comprises admixing an antioxidant. 
   
   
       35 . The method according to  claim 34 , wherein the antioxidant is based on one of phosphite and sterically hindered phenols. 
   
   
       36 . The method according to  claim 1 , which comprises admixing a UV light stabilizer. 
   
   
       37 . The method according to  claim 1 , which comprises providing a molding material with the following constituents:
 resin powder ≧60%   conversion material ≧0% and ≦40%   adhesion promoter ≧0% and ≦3%   mold release agent ≧0% and ≦2%   surface modifier ≧0% and ≦5%   antioxidant ≧0% and ≦5%   UV light stabilizer ≧0% and ≦2%   glass particles ≧0% and ≦80%.   
   
   
       38 . The method according to  claim 37 , which comprises adjusting the conversion material in the molding material to >10% and ≦25%. 
   
   
       39 . The method according to  claim 1 , wherein the step of encasing the leadframe comprises injection molding or injection compression molding. 
   
   
       40 . The method according to  claim 39 , which comprises mounting the radiation-emitting chip on a leadframe, introducing the radiation-emitting chip and a portion of the leadframe into an injection mold, liquefying the molding material, and injecting the molding material into the injection mold. 
   
   
       41 . The method according to  claim 39 , which comprises preheating the leadframe prior to the encasing step. 
   
   
       42 . The method according to  claim 1 , wherein the encasing step comprises encapsulating a plurality of leadframes, each having at least one radiation-emitting chip mounted thereon, with a cohesive covering and subsequently dividing into individual components. 
   
   
       43 . The method according to  claim 42 , wherein the dividing step comprises a process selected from the group consisting of breaking, sawing, laser cracking, or water jet sawing.