Osram Sylvania Inc.

Harry S Mackel

George C Wei

The present invention is a ceramic discharge vessel for use in high-intensity-discharge (HID) lamps. The discharge vessel has a ceramic body and at least one seal region comprised of an aluminum oxynitride material. The seal region further has a surface layer for contacting a frit material wherein the surface layer is less reactive than the aluminum oxynitride material with respect to the molten frit during sealing. Preferably, the surface layer has a lower nitrogen content than the aluminum oxynitride material. The less reactive surface acts to minimize the formation of bubbles in the sealing frit during the sealing operation.

Method of treating a ceramic discharge vessel

The present method uses a methane-containing nitrogen gas sintering atmosphere to sinter aluminum nitride (AlN) to a high transmittance. The methane gas replaces the solid carbon charge material used in prior art sintering methods as the source of gaseous carbon. The amount of carbon in the methane-containing nitrogen gas is easily controlled by varying the partial pressure of methane in the nitrogen gas. In addition, the methane flow is stopped prior to the end of the sintering cycle to prevent darkening of the sintered part.

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Pepperell, MA, United States of America

Harry S Mackel