Discharge lamp lighting device, control method for the same, and projector

A discharge lamp lighting device comprising:

• a power control circuit that outputs a DC current;
• an AC converter circuit to which the DC current is inputted, the AC converter circuit inverting polarity of the DC current between first polarity and second polarity in predetermined timing, and thereby generates and outputs an AC current for discharge lamp driving;
• and
• a control unit that carries out AC conversion control, current control and repair control, the AC conversion control processing to the AC converter circuit to control a duty ratio by polarity inversion timing of the AC current for discharge lamp driving, the current control processing to the power control circuit to control a current value of the DC current, the repair control conducting the current control processing to change, in a first cyclical pattern, a duty ratio that is a proportion of time of the first polarity in one cycle of the AC current for discharge lamp driving, in predetermined timing, the first cyclical pattern including plural sectional periods in which the duty ratio is maintained at the same value over plural cycles of the AC current for discharge lamp driving, and the duty ratio differs between at least two of the sectional periods.

A discharge lamp lighting device comprising:

• a power control circuit that outputs a DC current;
• an AC converter circuit to which the DC current is inputted, the AC converter circuit inverting polarity of the DC current between first polarity and second polarity in predetermined timing, and thereby generates and outputs an AC current for discharge lamp driving;
• and
• a control unit that carries out AC conversion control, sectional current control and repair control, the AC conversion control processing to the AC converter circuit to control polarity inversion timing of the AC current for discharge lamp driving, the sectional current control processing to the power control circuit to control a current value of the DC current in accordance with the polarity inversion timing section the repair control conducting the sectional current control processing to change, in a first cyclical pattern, a difference in absolute value between a current value in a first polarity section and a current value in a second polarity section of the AC current for discharge lamp driving, in predetermined timing, the first cyclical pattern including plural sectional periods in which the difference in absolute value between the current value in the first polarity section and the current value in the second polarity section of the AC current for discharge lamp driving is maintained at the same value over plural cycles of the AC current for discharge lamp driving, and the difference in absolute value between the current value in the first polarity section and the current value in the second polarity section of the AC current for discharge lamp driving differs between at least two of the sectional periods.

A control method for a discharge lamp lighting device including:

• a power control circuit that outputs a DC current;
• and
• an AC converter circuit to which the DC current is inputted, the AC converter circuit repeating polarity inversion of the DC current between first polarity and second polarity in predetermined timing and thereby generates and outputs an AC current for discharge lamp driving;
• the method comprising:
• carrying out AC conversion control processing to the AC conversion circuit to control polarity inversion timing of the AC current for discharge lamp driving;
• carrying out current control processing to the power control circuit to control a current value of the DC current;
• and
• carrying out repair control to change, in a first cyclical pattern, cumulative energy supplied to each electrode of the discharge lamp during one cycle of the AC current for discharge lamp driving, in predetermined timing, the first cyclical pattern including plural sectional periods in which the cumulative energy is maintained at the same value over plural cycles of the AC current for discharge lamp driving, and the cumulative energy differs between at least two of the sectional periods.