Patent ID: 6977472

Claim:
An electrodeless self-ballasted fluorescent lamp comprising: an electrodeless fluorescent lamp; a ballast circuit for applying a high-frequency voltage to the electrodeless fluorescent lamp; and a lamp base electrically connected to the ballast circuit, wherein the electrodeless fluorescent lamp, the ballast circuit and the lamp base are formed as one unit, wherein the ballast circuit comprises: an AC-DC converter for converting a phase-controlled AC voltage into a DC voltage; a DC-AC converter for converting the DC voltage into a high-frequency voltage, the DC-AC converter being formed so as to intermittently drive the electrodeless fluorescent lamp due to the existence of an operating period during which the high-frequency voltage is applied to the electrodeless fluorescent lamp so that the electrodeless fluorescent lamp is operated, and an extinguishing period during which the generation of the high-frequency voltage is stopped so that the electrodeless fluorescent lamp is extinguished; and a dimming controller formed so as to detect the turn-on of the phase-controlled AC voltage and output an intermittent command signal that changes the ratio between the operating period and the extinguishing period to the DC-AC converter, and wherein the dimming controller is formed so as to output a signal for extinguishing the electrodeless fluorescent lamp before the operation thereof becomes unstable.