Patent ID: 8827504

Claim:
A light bulb comprising: a first light guide configured as a hollow body surrounding an internal volume, the first light guide being open at a proximal end and a distal end, opposite the proximal end, and comprising an inner surface, an outer surface and an end surface at the proximal end that provides a light input edge; a solid-state light source optically coupled to the light input edge such that light from the solid-state light source travels in the light guide by total internal reflection; a housing at the proximal end of the light guide, the solid-state light source being thermally coupled to the housing, the housing defining vents for air flow and convection cooling through the internal volume; and light-extracting optical elements at least one of the inner surface and the outer surface of the light guide for extracting light from the light guide; and a second light guide comprising an inner surface facing toward the internal volume; wherein the second light guide is configured as a hollow body surrounding the internal volume, the second light guide being open at a proximal end and a distal end, opposite the proximal end, the second light guide comprises an outer surface and an end surface at the proximal end of the second light guide that provides a light input edge, wherein one of the light guides is positioned in the other light guide with an air gap between the light guides; a second solid-state light source is optically coupled to the light input edge of the second light guide such that light from the second solid-state light source travels in the second light guide by total internal reflection, the second solid-state light source being thermally coupled to the housing; and additional light-extracting optical elements are at least one of the inner surface and the outer surface of the second light guide to extract light from the second light guide.