Abstract: The present invention is directed to horizontally burning formed-body arc tubes and arc tube blanks for high intensity discharge lamps. The bottom portion of the light emitting chamber of the arc tubes is flattened in an area between the electrodes to reduce the distance between the bottom wall of the arc tube and the arc, and to increase the surface area of the pool of condensed halides during operation of a metal halide lamp. The flattened bottom of the arc tubes may be generally planar, slightly arcuate longitudinally and/or transversely, or slightly v-shaped longitudinally and/or transversely. The top portion of the arc tube conforms generally to the shape of the arc during operation of the lamp.

Abstract: A method of making an electric lamp having a gas filled outer jacket wherein the space enveloped by the jacket may be flushed and filled with the desired fill gas without the use of a mechanical evacuation system including an exhaust pump. The space may be flushed and filled to obtain a controlled atmosphere within the space by inserting a gas dispensing probe into the space to displace the uncontrolled atmosphere with the fill gas. The final pressure of the fill gas which is sealed within the space may be controlled by controlling the temperature of the fill gas during the flush/fill procedure until the outer jacket is sealed.