Ceramic arc tube of metal vapor discharge lamps and a method of producing the same

摘要

The disclosed ceramic arc tube of metal vapor discharge lamps has an arc discharge portion with electrode-holding end portions integrally formed at opposite ends thereof. The outside diameter of the arc discharge portion is larger than that of the electrode-holding end portions. The ceramic arc tube is made by placing a tubular green body in a fusiform cavity of a die, inflating the middle portion of the green body more than end portions thereof, and firing the thus shaped green body.