Ceramic envelope device, lamp with such a device, and method of manufacture of such devices
 This invention involves a new type of feedthrough-plug member for metal halide HID lamp using PCA envelopes. The construction of the lamp housing consists of a PCA envelope and specially designed axially graded alumina-metal cermet multi-layers to eliminate cracking in cermet or PCA due to thermal stresses arising from thermal expansion mismatch. The fills are metal halides such as Na--Sc--I, rare earth halides, Hg, Sn, and inert gases. The PCA vessel and directly sealed cermet-feedthrough assemblies allow the metal halide lamps to operate at high wall temperatures with better lumen output, color temperature, and CRI. 
Osram Sylvania Inc.
H H
H01J H01J
inventional inventional
Rodrique G. George C. Stefan John
Thibodeau Wei Juengst Selverian