| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting apparatus in which an overshoot is controlled at a time of a polarity reversal of an alternative rectangular wave current to light a high-pressure discharge lamp and a light utilization efficiency in forming an image is improved. <P>SOLUTION: A direct-current voltage inputted from a power source 11 is lowered by a converter 12 and supplied to an inverter 15. The inverter 15 converts the inputted direct-current power into an AC power and generates a high pressure voltage at a lamp starting up circuit 16 and supplies to the high-pressure discharge lamp 17 and lights the high pressure-discharge lamp 17. An output pulse d of different frequencies is supplied by a pulse width modulation part 19 which drives the converter 17. An occurrence of an overshoot at switching of switch elements S1, S2, S3, S4 of the inverter 15 can be controlled by synchronizing with a falling and a rising of a driving pulse signal g for switching on-off the switch elements S1 to S4 of the inverter 15 and by driving temporarily the converter 12 at an output pulse d of a high frequency by a switching signal h to change a duty of the pulse width modulation part 19. <P>COPYRIGHT: (C)2008,JPO&INPIT |
