Method of making a double-ended high-pressure discharge lamp

摘要

To make a small high-pressure discharge lamp, for example of 50 W rating or less, and suitable, for example, for automotive applications, a quartz glass tube is heated, formed with constrictions, and a gas passed therebetween to expand the portion of the tube between the constrictions into olive shape to form the discharge vessel (6). A preformed first electrode system is introduced through one of the constrictions. The electrode system preferably has a zig-zag lead (9) slightly larger than the internal diameter of the tube to provide for self-centering. The tube is then isolated from atmosphere, for example by being placed in a glove box or coupled to a pumping head (15), for introduction therein of a fill substance, for example in pellet form, of a metal halide and, if desired, mercury; and a fill gas, such as argon or, preferably, xenon, preferably after cleaning and flushing the tube. A second electrode system is then introduced, for example within the glove box, and the end of the tube sealed off, with the fill substance therein. A second pinch seal (18) can then be formed externally of the glove box, or while the tube is still connected to a pumping head, and excess end pieces of the tube and the electrodes are cut off.