Metal Halide Discharge Lamp and Metal Halide Discharge Lamp System

Abstract

[Problems] To provide a metal halide discharge lamp essentially not having mercury that is lighted stably so that a discharge arc is corrected into the straight state against the gravity induced convection using an acoustic resonance phenomenon, and a metal halide discharge lamp system for lighting the same. [Means of Solving Problems] A metal halide discharge lamp MHL includes a fire-resistant and light-transmitting hermetic vessel 1 with the maximum inner diameter of 2.0 to 12.0 mm, a pair of electrodes 2A, 2B, and a discharge medium containing a halide and a rare gas and essentially not containing mercury and sealed within the hermetic vessel, wherein the discharge arc is stably made into straight even if the lamp is lighted by flowing an electric current superimposed with a ripple current with either of a predetermined frequency in a range of a relatively low first frequency f1 satisfying an equation 1 (unit: kHz) and a relatively high second frequency f2 satisfying an equation 2 (unit: kHz) in the hermetic vessel.

Dependencies are inferred from the claim text.