DIMMING METHOD FOR DISCHARGE LAMP AND DISCHARGE LAMP LIGHTING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a dimming method for a discharge lamp improving a dimming control range and preventing flickering by controlling the number of times of lighting of the discharge lamp of an outer electrode type, and to provide a discharge lamp lighting device. SOLUTION: The dimmer control circuit 20 receives a dimming signal Sig which is an indication signal directing increasing/lowering of the light emitting luminance of the discharge lamp and generates a control signal S1 according to the dimming signal Sig to output it to a rectangular wave signal generating circuit 40. The rectangular wave signal generating circuit 40 generates a rectangular wave signal Vp of a frequency according to the control signal S1 to output it to a driving signal generating circuit 50.The frequency of the rectangular wave signal Vp is adjusted in a range of 5-30 kHz according to the dimming signal Sig. The frequency of a rectangular wave voltage Vr2 applied between the electrodes of a rare gas discharge lamp 80 is increased/decreased by increasing/decreasing the frequency of the rectangular wave signal Vp to control the number of times of discharge per unit time. Thereby, the light emitting luminance of the rare gas discharge lamp 80 can be controlled to a desired value. COPYRIGHT: (C)2005,JPO&NCIPI