Patent ID: 6975078

Claim:
A dimming-control lighting apparatus for an incandescent electric lamp, the apparatus controlling the dimming to light a lighting device that uses the incandescent electric lamp as a light source by means of a dimming power source employing ignition phase angle control, comprising: the lighting device including a first filament in which the rated voltage is less than the maximum output voltage of the dimming power source, and a second filament, having the same rated voltage as the maximum output voltage of the dimming power source; a first power control unit connected to the first filament; a second power control unit connected to the second filament; and control means for controlling the first and second power control units connected to the first and second filaments, respectively, based on a sawtooth voltage that is supplied from the dimming power source and changed by adjusting the dimming, wherein the control means, while maintaining a dimming characteristic of the dimming power source, is arranged to control the first and second power control units so as to first light the first filament, to start lighting the second filament after the color temperature of light emitted from the first filament reaches a predetermined value, to compensate for degradation of the total color temperature due to the lighting start of the second filament by means of further increase of supply voltage for the first filament, and to increase the supply voltages for both the first and second filament in conformity with the dimming characteristic.