Document Type and Number:
Japanese Patent JPS4945578
Kind Code:
A
Abstract:
A high intensity sodium vapor arc lamp utilizing a slender tubular envelope of alumina ceramic having self-heating electrodes mounted at opposite ends and containing an excess pool of liquid sodium-mercury amalgam at the cold spot in the lower end. The electrode at the lower end includes a resistive heater portion and lamp current flowing therethrough provides supplementary heat to the amalgam pool varying according to lamp current. In conjunction with the inductive ballast characteristic this stabilizes the cold spot temperature and amalgam vapor pressure, and counters the tendency to arc voltage rise with life. It also reduces the sensitivity of the lamp to radiant energy reflected back from the fixture.
Application Number:
JP8052873A
Publication Date:
May 01, 1974
Filing Date:
July 19, 1973
Export Citation:
International Classes:
H01J61/24; H01J61/073; H01J61/28; H01J61/52; (IPC1-7): H01J61/74