Patent ID: 7898191
Filing Date: 2011-03-01
Classification: H05B,Y02B

Abstract:
1. A discharge lamp lighting device including: an inverter circuit that includes one or a plurality of switching elements and converts a direct current input into a high frequency alternating current output by switching the switching elements at a high frequency; one or a plurality of resonating inductors and one or a plurality of resonating capacitors, which compose a resonant circuit together with a discharge lamp and are connected between output terminals of the inverter circuit; and a light adjustment control circuit that adjusts high frequency electric power supplied from the inverter circuit through the resonant circuit to the discharge lamp by controlling the switching of the switching elements, wherein the light adjustment control circuit includes: electric power correcting means for controlling the high frequency electric power of the inverter circuit to gradually increase following elapse of an operating time of the discharge lamp during a period from an operation start of the discharge lamp to a predetermined time after the discharge lamp reaches a rated lifetime thereof; and electric power suppressing means for controlling the high frequency electric power of the inverter circuit to become a predetermined value or less on and after the predetermined time, and the predetermined value is a value larger than 1.2 times electric power defined by a tube shape, tube length and tube diameter of the discharge lamp.