Rapid-start single-ended high-pressure discharge lamp

Abstract

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.