ACOUSTIC RESONANCE OPERATION FOR XENON-METAL HALIDE LAMPS

摘要

A circuit arrangement and a method of operating a highly desirable discharge lamp for automotive applications are disclosed. The discharge lamp contains a high xenon pressure along with a fill of mercury and a halide typically used for metal halide lamps. The high xenon pressure allows the xenon-metal halide lamp to obtain instantaneous light at a high intensity level which is particularly suited for automotive applications. The circuit related to the present invention provides for acoustic operation of the lamp which substantially eliminates known disadvantages of the high pressure xenon lamp of (1) severe arc bowing of such lamps having electrode spacing greater than two (2) millimeters; (2) increased hot-spot temperatures of such lamps; (3) decreased cold-spot temperatures of said lamps and (4) reduced lamp efficiency and life respectively due to decreased cold spots and increased hot-spot temperatures. The circuit in a preferred embodiment incorporates frequency modulation to broaden the desired operational frequency band of the circuit along with straightening the arc between electrodes of the high-pressure xenon-metal halide lamp.