BEAM MODE FLUORESCENT LAMP WITH DUAL CATHODE OF SAME POTENTIAL AT BOTH ENDS OF EACH CATHODE

摘要

A beam mode lamp has two thermionic electrodes (33, 34) which when energized by AC power function alternately as cathode and anode. Electrodes emitted from a cathode are shaped by the anode into electron beams (e) which excite a gaseous mixture into radiating ultraviolet light and seconary electrons. A phosphor coating (37) on the envelope (31) of the lamp connects the ultraviolet radiation into visible light. During start the electrodes (33, 34) are connected in series. During operation the electrodes (33, 34) are disconnected from each other. The ends of each electrode are then connected making the two ends of an electrode at substantially the same electrical potential. This arrangement results in improved luminous output efficacy and longer operating life of the lamp.