Patent ID: 9729838
Date: 2017-08-08
CPC Classifications: G03B,H04N,H05B

Claim:
1. A discharge lamp driver comprising: a discharge lamp drive unit that supplies a drive current for driving a discharge lamp to the discharge lamp; and a control unit that controls the discharge lamp drive unit according to a drive current waveform, wherein the drive current waveform has a mixed frequency drive period including a unit drive period containing a first drive period in which a first drive current is supplied to the discharge lamp and a second drive period provided immediately after the first drive period, in which a second drive current is supplied to the discharge lamp, the first drive current is a half-period alternating current having a frequency higher than 10 Hz and not higher than 300Hz, the second drive current is an alternating current having a frequency higher than 1000 Hz, a length of the second drive period is equal to or longer than a length of the first drive period, the unit drive period contains the first unit drive period in which the first drive current has one polarity and the second unit drive period in which the first drive current has the other polarity, and the mixed frequency drive period contains a first mixed frequency drive period including the first unit drive period and a second mixed frequency drive period including the second unit drive period.