Solid-state light emitting devices with photoluminescence wavelength conversion

Abstract

A solid-state light emitting device comprises a light transmissive thermally conductive circuit board; an array of solid-state light emitters (LEDs) mounted on, and electrically connected to, at least one face of the circuit board; and a photoluminescence wavelength conversion component. The wavelength conversion component comprises a mixture of particles of at least one photoluminescence material (phosphor) and particles of a light reflective material. The emission product of the device comprises the combined light generated by the LEDs and the photoluminescence material. The wavelength conversion component can comprise a layer of the phosphor material and particles of a light reflective material applied directly to the array of LEDs in the form of an encapsulant. Alternatively the photoluminescence component is a separate component and remote to the array of LEDs such as tubular component that surrounds the LEDs.

1 . (canceled) 
     
     
         2 . A method to implement a light emitting device comprising:
 identifying a first amount of at least one photoluminescence material to be included in a photoluminescence wavelength conversion component, where the photoluminescence wavelength conversion component is operable in conjunction with at least one solid-state light emitter operable to generate excitation light to produce light emissions having a given color or intensity; and   identifying an amount of light reflective material to include such that the photoluminescence wavelength conversion component comprises a mixture of particles of a second amount of the at least one photoluminescence material and particles of the light reflective material, where the photoluminescence wavelength conversion component is operable to generate the light emissions having the given color or intensity;   wherein the second amount is less than the first amount of the at least one photoluminescence material.   
     
     
         3 . The method of  claim 2 , wherein an area over which the mixture is distributed is at least fifty times the light emitting area of the light emitter. 
     
     
         4 . The method of  claim 2 , wherein the wavelength conversion component is locatable at a distance of at least 5 mm from the at least one light emitter. 
     
     
         5 . The method of  claim 2 , wherein the light reflective material has a particle size in a range selected from the group consisting of: 0.01 μm to 10 μm; 0.01 μm to 1 μm and 0.1 μm to 1 μm. 
     
     
         6 . The method of  claim 2 , wherein a weight percent loading of light reflective material to the at least one photoluminescence material is in a range selected from the group consisting of: 0.01% to 10%; 0.01% to 1%; 0.1% to 1% and 0.5% to 1%. 
     
     
         7 . The method of  claim 2 , wherein the light reflective material is selected from the group consisting of: magnesium oxide, titanium dioxide, barium sulfate and combinations thereof. 
     
     
         8 . The method of  claim 2 , wherein the wavelength conversion component is selected from the group consisting of: a light transmissive substrate on which the mixture is provided as at least one layer; a light transmissive substrate configured as a light guide and wherein the mixture is provided on at least a part of a face of the light guide; a light transmissive substrate having the mixture is homogeneously distributed throughout its volume and a light reflective surface on which the mixture is provided as at least one layer. 
     
     
         9 . The method of  claim 2 , wherein the at least one solid-state light emitter comprises an LED that is operable to generate blue excitation light having a peak wavelength in a wavelength range 440 nm to 480 nm. 
     
     
         10 . The method of  claim 2 , wherein the mixture of the photoluminescence material and the light reflective material is distributed over an area of at least 0.8 cm 2 . 
     
     
         11 . The method of  claim 2 , wherein the particles of the light reflective material corresponds to a particle size such that the particles of the light reflective material scatter excitation light relatively more than light generated by the at least one photoluminescence material. 
     
     
         12 . The method of  claim 2 , further comprising inclusion of a light diffusing material. 
     
     
         13 . The method of  claim 12 , wherein the light diffusing material is included as a layer that is adjacent to the photoluminescence wavelength conversion component. 
     
     
         14 . The method of  claim 13 , in which the layer having the light diffusing material comprises particles of light reflective material corresponding to a particle size such that the particles of light reflective material scatter excitation light relatively more than light generated by the at least one photoluminescence material. 
     
     
         15 . The method of  claim 14 , wherein the light reflective material has a particle size in a range 100 nm to 150 nm. 
     
     
         16 . The method of  claim 2 , in which the at least one photoluminescence material comprises phosphor or quantum dots. 
     
     
         17 . The method of  claim 2 , wherein the photoluminescence wavelength conversion component is remotely located from the at least one solid-state light emitter. 
     
     
         18 . The method of  claim 2 , wherein the second amount is less than the first amount of the at least one photoluminescence material by about 25%. 
     
     
         19 . The method of  claim 2 , wherein the photoluminescence wavelength conversion component is formed using a technique selected from the group consisting of: screen printing, slot die coating, spin coating, roller coating, drawdown coating, and doctor blading.