摘要 |
PROBLEM TO BE SOLVED: To solve problems with a composite driving method that alternately supplies a high frequency AC current and a low frequency square wave alternating current.SOLUTION: A method of driving a discharge lamp 500 having electrodes 610, 710 oppositely arranged in a cavity part 512 encapsulating a discharge medium supplies an AC current switching between a high frequency and a low frequency between the electrodes 610, 710. The period for which the low frequency AC current is supplied includes: a first interval A in which a first direct current is supplied in positive polarity; a second interval B in which a first alternating current is supplied; a third interval C in which the first direct current is supplied in negative polarity; a fourth interval D in which the first alternating current is supplied; a fifth interval E in which a second direct current is supplied in positive polarity; a sixth interval F in which a second alternating current is supplied; a seventh interval G in which the second direct current is supplied in negative polarity; and an eighth interval H in which the second alternating current is supplied. |