Patent Treuhand Gesellschaft Fur Elektrische Gluhlampen Mbh

Patent Treuhand Fur Elektrische Gluhlampen M.b.h.

Richard Kotschenreuther

Jurgen Heider

Dieter Lang

Wolfgang Schade

Hartmuth L Bastian

Stefan Kotter

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.

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

To provide for a long electrode shaft, which insures rapid and reliable sting of the lamp, the electrodes are formed with a straight shaft portion extending from a pinch or press seal (8) and then twisted into a loop (20, 21) which terminates in discharge tips (18, 19), facing each other across the center line of the lamp. The loops, preferably, include a circular portion of about 270.degree., with a radius of greater than the radius of the diameter of the wires--typically of tungsten--and offset with respect to the electrode shaft so that, at cross-over points (24, 25) the looped portion (20, 21) of the respective electrode and the straight or shaft portion (22, 23) of the electrode do not touch each other; a very small spacing, for example 0.05 mm, with electrode wires of 0.2 mm diameter, is sufficient. The electrodes can be identical, so that, in facing positions, the loops will be on opposite sides with respect to a plane passing through the center of the lamp, and the electrodes, then, can be twisted by an angle in the order of about 30.degree., or somewhat less, e.g. 27.degree., so that the electrode wire tips will be in-line (L) with respect to each other to reliably and continuously throughout the lift of the lamp define the discharge zone in a predetermined relation or position with respect to the remainder of the lamp so that, upon inclusion in an optical system (e.g. a reflector) (R), the light emitting zone will, reliably, remain constant in relation to the optical system.

Rapid-start single-ended high-pressure discharge lamp

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Munich, Germany

Richard Kotschenreuther