Wavelength-converting casting composition and white light-emitting semiconductor component

Abstract

The wavelength-converting casting composition is based on a transparent epoxy casting resin with a luminous substance admixed. The composition is used in an electroluminescent component having a body that emits ultraviolet, blue or green light. An inorganic luminous substance pigment powder with luminous substance pigments is dispersed in the transparent epoxy casting resin. The luminous substance is a powder of garnets, thiogallates, aluminates, or orthosilicates doped with rare earths, and preferably Ce-doped phosphors. The luminous substance pigments have particle sizes≦20 μm and a mean grain diameter d 50 <5 μm.

We claim:  
     
         1 . A wavelength-converting casting composition, comprising: 
 a transparent casting resin;    an inorganic luminous substance pigment powder dispersed in said transparent casting resin, said pigment powder comprising luminous substance pigments selected from the group consisting of garnets doped with rare earths; thiogallates doped with rare earths; aluminates doped with rare earths; and    orthosilicates doped with rare earths; and said luminous substance pigments having grain sizes≦20 μm and a mean grain diameter d 50 <5 μm.    
     
     
         2 . The casting composition according to  claim 1 , wherein said luminous substance pigments are substantially spherical particles.  
     
     
         3 . The casting composition according to  claim 1 , wherein said luminous substance pigments are flakelike particles.  
     
     
         4 . The casting composition according to  claim 1 , wherein the mean grain diameter d 50  of said luminous substance pigments is between one and two micrometers.  
     
     
         5 . The casting composition according to  claim 1 , which comprises the following components: 
 a) epoxy casting resin≧60% by weight;    b) luminous substance pigments>0 and ≦25% by weight;    c) thixotropic agent>0 and ≦10% by weight;    d) mineral diffusor>0 and ≦10% by weight;    e) processing adjuvant>0 and ≦3% by weight;    f) hydrophobic agent>0 and ≦3% by weight; and    g) adhesion promoters>0 and ≦2% by weight.    
     
     
         6 . The casting composition according to  claim 1 , wherein said luminous substance pigments are Ce-doped garnets.  
     
     
         7 . The casting composition according to  claim 1 , wherein said luminous substance pigments are YAG:Ce based particles.  
     
     
         8 . The casting composition according to  claim 1 , which comprises a content of iron≦20 ppm.  
     
     
         9 . The casting composition according to  claim 1 , wherein said luminous substance pigments are formed with a silicon coating.  
     
     
         10 . The casting composition according to  claim 1 , wherein said luminous substance pigment powder and said casting resin are adjusted to convert a wavelength of ultraviolet, blue, or green light into a relatively longer wavelength.  
     
     
         11 . The casting composition according to  claim 1 , wherein said luminous substance pigments are formed of a material from a phosphorus group having the general formula A 3 B 5 X 12 :M, where A is at least one element selected from the group consisting of Y, Gd, Lu, Sc, and La; B is at least one element selected from the group consisting of Al and Ga; X is O; M is at least one element selected from the group consisting of Ce, Eu, Cr, Nd, Er, and Tb.  
     
     
         12 . The casting composition according to  claim 1 , which comprises light-scattering particles added to said casting resin.  
     
     
         13 . A light-emitting semiconductor component, comprising: 
 a semiconductor body formed of a semiconductor layer sequence and being capable; during an operation of the semiconductor component, of emitting electromagnetic radiation in a first spectral range selected from ultraviolet, blue, and green;    a wavelength-converting casting composition disposed in a vicinity of said semiconductor body and formed of a transparent casting resin and an inorganic luminous substance pigment powder dispersed in said transparent casting resin;    said pigment powder comprising luminous substance pigments selected from the group consisting of garnets doped with rare earths; thiogallates doped with rare earths; aluminates doped with rare earths; and orthosilicates doped with rare earths; and    said luminous substance pigments having grain sizes≦20 μm and a mean grain diameter d 50 ≦5 μm and converting a portion of the radiation originating from said semiconductor component into radiation of a higher wavelength, such that the semiconductor component emits mixed radiation including the higher-wavelength radiation and radiation from the first spectral range.    
     
     
         14 . The light-emitting semiconductor component according to  claim 13 , wherein said casting composition encloses at least a part of said semiconductor body.  
     
     
         15 . The light-emitting semiconductor component according to  claim 13 , wherein said semiconductor body is adapted to emit radiation in a blue spectral range having a maximum luminescence intensity at λ=430 nm or at λ=450 nm.  
     
     
         16 . The light-emitting semiconductor component according to  claim 13 , which further comprises an opaque base housing having a recess formed therein, said semiconductor body being disposed in said recess and said recess being at least partially filled with said casting composition.  
     
     
         17 . The light-emitting semiconductor component according to  claim 13 , wherein said casting composition is provided with various kinds of luminous substance pigments in respect to a host lattice distribution and a type and extent of doping.  
     
     
         18 . The light-emitting semiconductor component according to  claim 13 , wherein said semiconductor body is a blue light emitting semiconductor body, and said luminous substance pigments are Ce-doped phosphors adapted to shift some of the blue light emitted by said semiconductor body into a yellow spectral range, whereby the semiconductor component emits white light.  
     
     
         19 . The light-emitting semiconductor component according to  claim 13 , wherein said semiconductor body is a blue light emitting semiconductor body, and said luminous substance pigments shift some of the blue light emitted by said semiconductor body into a green and red spectral range, whereby the semiconductor component emits white light.  
     
     
         20 . The light-emitting semiconductor component according to  claim 13 , wherein said pigment are formed of a material from a phosphorus group having the general formula A 3 B 5 X 12 :M, where A is at least one element selected from the group consisting of Y, Gd, Lu, Sc, and La; B is at least one element selected from the group consisting of Al and Ga; X is O; M is at least one element selected from the group consisting of Ce, Eu, Cr, Nd, Er, and Tb.  
     
     
         21 . The light-emitting semiconductor component according to  claim 13 , wherein the mean grain diameter d 50  of said luminous substance pigments is between one and two micrometers.  
     
     
         22 . The light-emitting semiconductor component according to  claim 13 , which comprises light-scattering particles added to said casting resin.  
     
     
         23 . The light-emitting semiconductor component according to  claim 13 , wherein said luminous substance pigment powder is a tempered pigment powder.