US Patent 7781977 - High temperature photonic structure for tungsten filament

http://ip.com/patent/US7781977

Infrared emission can reduce the energy efficiency of incandescent lamps up to 70%. This patent from GE teaches forming a thin film of metal nanoparticles on a light source in order to suppress the emission of infrared wavelengths. Claim 1 reads:

1. A light source comprising

emissive components having deposited thereon a thin film metal layer in the form of a photonic lattice comprising discreet nano-particles,

the light source exhibiting a suppression of emissions in excess of 900 nm and a shift thereof to wavelengths in the visible or lower infrared spectrum during operation.