| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce dispersion in the starting characteristics of a discharge lamp resulting from individual difference of discharge lamps. SOLUTION: A lamp lighting circuit 1 comprises a lamp voltage sensing circuit 9 which is to obtain signals about the lamp voltages of discharge lamps 11, 11', a lamp current sensing circuit 8 which is to obtain signals about the lamp currents of the lamps 11, 11', and a voltage-current characteristics control circuit 13 which performs the light-up control of the lamps in conformity to the control curves according to the lamp voltage vs. lamp current characteristics to specify the relation between the lamp voltage and lamp current on the basis of the sensing signals given by the sensing circuits 9 and 8. Among the control curves, the one in a region nearer the lamp voltage axis is made straight parallel with the lamp axis, and the lamp current is controlled approx. constant in this region.</p> |
