Patent ID: 7768207

Claim:
A high intensity lamp comprising a visible-light-transmissive polycrystalline alumina envelope material that is modified by combination of said material with a composite metal oxide coating, source, or dopant, having: (i) an oxide of at least one of zinc, indium, tin, zirconium, hafnium, tungsten, lanthanum, lutetium, silicon, or other oxide with melting point exceeding about 1300° C.; (ii) a binary or ternary or high-order alloy of an oxide of (i); (iii) any of (i) or (ii) doped with one or more of zinc, aluminum, indium, tin, zirconium, hafnium, tungsten, silicon, or other dopant resulting in a composite coating having a melting point exceeding about 1300° C.; or (iv) combinations thereof, wherein said lamp exhibits total hemispherical emittance of greater than 0.20 at 1300° K. due to the void-free and compactness of the coating.