PURPOSE: To reduce the starting voltage while suppressing the stray light by providing an ionizing electrode near the shrunk end of a discharge path.
CONSTITUTION: A discharge path limiter 5 inserted between an anode 9a and a cethode 2 and shrinking one end on the cathode side of a discharge path arranged in response to the number of anodes, a fluorescent film 8 coated on the surface facing the discharge path of the discharge path limiter 5 or a bulb 1, and an ionizing electrode 13 arranged near the shrunk end of the discharge path 7a are provided. The ionizing electrode 13 is inserted between the cathode 2 and the anode 9a and also arranged near the shrunk end of the discharge path provided to prevent the stray light, thus an ionization state occurs between the cathode 2 and the anode 9a by the excitation of the ionizing electrode 13, the impedance near the shrunk end of the discharge path 7a is reduced, and the starting voltage between the cathode 2 and the anode 9a can be reduced while the stray light is prevented.
YUGE YOJI
NAKAJIMA JUNICHI
TOSHIBA ELECTRIC EQUIP