Solid state light emitter with pumped nanophosphors for producing high cri white light

Abstract

A solid state white light emitting device includes a semiconductor chip producing near ultraviolet (UV) energy. The device may include a reflector forming and optical integrating cavity. Phosphors, such as doped semiconductor nanophosphors, within the chip packaging of the semiconductor device itself, are excitable by the near UV energy. However the re-emitted light from the phosphors have different spectral characteristics outside the absorption ranges of the phosphors, which reduces or eliminates re-absorption. The emitter produces output light that is at least substantially white and has a color rendering index (CRI) of 75 or higher. The white light output of the emitter may exhibit color temperature in a range along the black body curve.

1 - 19 . (canceled) 
     
     
         20 . A solid state light emitting device, comprising:
 a semiconductor chip for producing electromagnetic energy in a range of 380-420 nm;   a package enclosing the semiconductor chip and configured to allow emission of light as an output of the device; and   a plurality of doped semiconductor nanophosphors within the package enclosing the semiconductor chip, each of the doped semiconductor nanophosphors:
 including nanocrystals formed of semiconductor materials which are doped with an impurity, 
 being of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting visible light of a different spectrum having substantially no overlap with absorption spectra of the doped semiconductor nanophosphors, and 
 for together producing visible light in the output of the device when the doped semiconductor nanophosphors are excited by electromagnetic energy from the semiconductor chip, 
   wherein:
 (a) the visible light output produced during the excitation of the doped semiconductor nanophosphors is at least substantially white; 
 (b) the visible light output produced during the excitation of the doped semiconductor nanophosphors has a color rendering index (CRI) of 75 or higher; and 
 (c) the visible light output produced during the excitation of the doped semiconductor nanophosphors has a color temperature in one of the following ranges:
 2,725±145° Kelvin; 
 3,045±175° Kelvin; 
 3,465±245° Kelvin; 
 3,985±275° Kelvin; 
 4,503±243° Kelvin; 
 5,028±283° Kelvin; 
 5,665±355° Kelvin; and 
 6,530±510° Kelvin. 
 
   
     
     
         21 . A solid state light emitting device, comprising:
 a semiconductor chip for producing electromagnetic energy in a range of 380-420 nm;   a package enclosing the semiconductor chip and configured to allow emission of light as an output of the device; and   a plurality of doped semiconductor nanophosphors within the package enclosing the semiconductor chip, each of the doped semiconductor nanophosphors:
 including nanocrystals formed of semiconductor materials which are doped with an impurity, 
 being of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting visible light of a different spectrum having substantially no overlap with absorption spectra of the doped semiconductor nanophosphors, and 
 for together producing visible light in the output of the device when the doped semiconductor nanophosphors are excited by electromagnetic energy from the semiconductor chip, 
   wherein:
 (a) the visible light output produced during the excitation of the doped semiconductor nanophosphors is at least substantially white; 
 (b) the visible light output produced during the excitation of the doped semiconductor nanophosphors has a color rendering index (CRI) of 75 or higher; and 
 (c) the visible light output produced during the excitation of the doped semiconductor nanophosphors has a color temperature in one of the following ranges:
 2,725±145° Kelvin; 
 3,045±175° Kelvin; 
 3,465±245° Kelvin; 
 3,985±275° Kelvin; 
 4,503±243° Kelvin; 
 5,028±283° Kelvin; 
 5,665±355° Kelvin; and 
 6,530±510° Kelvin, and 
 
   wherein the plurality of doped semiconductor nanophosphors comprises:   a doped semiconductor nanophosphor of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting orange light;   a doped semiconductor nanophosphor of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting blue light; and   a doped semiconductor nanophosphor of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting green light.   
     
     
         22 . The solid state light emitting device of  claim 21 , wherein the plurality of doped semiconductor nanophosphors further comprises a doped semiconductor nanophosphor of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting yellowish-green or greenish-yellow light. 
     
     
         23 . The solid state light emitting device of  claim 21 , wherein the visible light output produced during the excitation of the doped semiconductor nanophosphors has a CRI of at least 80. 
     
     
         24 . A solid state light emitting device, comprising:
 a semiconductor chip for producing electromagnetic energy in a range of 380-420 nm;   a package enclosing the semiconductor chip and configured to allow emission of light as an output of the device; and   a plurality of doped semiconductor nanophosphors within the package enclosing the semiconductor chip, each of the doped semiconductor nanophosphors:
 including nanocrystals formed of semiconductor materials which are doped with an impurity, 
 being of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting visible light of a different spectrum having substantially no overlap with absorption spectra of the doped semiconductor nanophosphors, and 
 for together producing visible light in the output of the device when the doped semiconductor nanophosphors are excited by electromagnetic energy from the semiconductor chip, 
   wherein:
 (a) the visible light output produced during the excitation of the doped semiconductor nanophosphors is at least substantially white; 
 (b) the visible light output produced during the excitation of the doped semiconductor nanophosphors has a color rendering index (CRI) of 75 or higher; and 
 (c) the visible light output produced during the excitation of the doped semiconductor nanophosphors has a color temperature in one of the following ranges:
 2,725±145° Kelvin; 
 3,045±175° Kelvin; 
 3,465±245° Kelvin; 
 3,985±275° Kelvin; 
 4,503±243° Kelvin; 
 5,028±283° Kelvin; 
 5,665±355° Kelvin; and 
 6,530±510° Kelvin, and 
 
   wherein the plurality of doped semiconductor nanophosphors comprises:   a doped semiconductor nanophosphor of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting red light;   a doped semiconductor nanophosphor of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting green light; and   a doped semiconductor nanophosphor of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting blue light.   
     
     
         25 . The solid state light emitting device of  claim 24 , wherein the plurality of doped semiconductor nanophosphors further comprises a doped semiconductor nanophosphor of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting yellow light. 
     
     
         26 . The light fixture of  claim 25 , wherein the visible light output produced during the excitation of the doped semiconductor nanophosphors has a CRI of at least 88. 
     
     
         27 . The solid state light emitting device of  claim 20 , wherein the semiconductor chip is configured for producing electromagnetic energy of 405 nm. 
     
     
         28 . The solid state light emitting device of  claim 20 , further comprising:
 at least one reflective surface within the package forming an optical integrating cavity;   wherein the semiconductor chip is positioned and oriented so that at least substantially all direct emissions from the semiconductor chip reflect at least once within the cavity.   
     
     
         29 . The solid state light emitting device of  claim 28 , wherein the at least one reflective surface is diffusely reflective. 
     
     
         30 . The solid state light emitting device of  claim 28 , further comprising:
 a light transmissive solid filling at least a substantial portion of the optical integrating cavity; wherein:   a surface of the light transmissive solid forms an optical aperture of the optical integrating cavity.   
     
     
         31 . A solid state light emitting device, comprising:
 a semiconductor chip for producing electromagnetic energy in a range of 380-420 nm;   a package enclosing the semiconductor chip;   at least one reflective surface forming an optical integrating cavity within the package, wherein the semiconductor chip is positioned and oriented so that at least substantially all direct emissions from the semiconductor chip reflect at least once within the cavity;   a light transmissive solid filling at least a substantial portion of the optical integrating cavity, wherein a surface of the light transmissive solid forms an optical aperture of the optical integrating cavity to allow emission of light from the cavity for a light output of the device; and   a plurality of phosphors, each of the phosphors being of a type excited in response to electromagnetic energy in the range of 380-420 nm for re-emitting visible light of a different spectrum having substantially no overlap with absorption spectra of the phosphors, for together producing visible light in the light output of the device when the phosphors are excited by electromagnetic energy from the semiconductor chip, wherein:
 (a) the visible light output produced during the excitation of the phosphors is at least substantially white; and 
 (b) the visible light output produced during the excitation of the phosphors has a color rendering index (CRI) of 75 or higher. 
   
     
     
         32 . The solid state light emitting device of  claim 31 , wherein the phosphors in the device comprise a plurality of doped semiconductor nanophosphors. 
     
     
         33 . The solid state light emitting device of  claim 32 , wherein emissions of the doped semiconductor nanophosphors cause the visible light output of the device to have a color temperature in one of the following ranges:
 2,725±145° Kelvin;   3,045±175° Kelvin;   3,465±245° Kelvin;   3,985±275° Kelvin;   4,503±243° Kelvin;   5,028±283° Kelvin;   5,665±355° Kelvin; and   6,530±510° Kelvin.