JPS5684862A - Metal vapor discharge lamp - Google Patents

Abstract

PURPOSE:To make the absorption ability of a getter most efficient, as well as prevent any rise in the starting voltage and increased the duration of the luminous flux, by accommodating a getter in a tubing protruding out of the luminous tube and heating the getter so that it may perform the dssigned absorption. CONSTITUTION:A luminous tube 1 of a metal halide lamp or the like is provided with the projection of a tubing 6, inside which a getter, such as a titanium getter, is contained. An electrode 4b, an electric wire, a heater 10 which heats the tubing 6, and the tubing 6 are connected in series, in that order. Voltage applied across the electrode 4b and a starting auxiliary electrode 5, causes discharge to be initiated. The rise in temperature which results from the discharge opens a bimetal switch 14, a sine voltage from a stabilizer 17 is added with the kick voltage of the bimetal 14, and the main discharge is shifted upon the discharge between the main electrodes 4a and 4b. From this point on, the discharge current flows through the heater 10, the getter is heated, and H2 gas or the like which might flow into the luminous tube 1 can be effectively absorbed.