Patent ID: 8598801
Filing Date: 2013-12-03
Classification: H05B

Abstract:
1. An electric supply device for a high pressure discharge lamp for supplying alternating current to the high pressure discharge lamp used as a light source of a liquid crystal projector apparatus, comprising: an electric supply device control unit configured to switch between a steady lighting mode, in which first electric power that is not less than 70% of a rated power is supplied to the high pressure discharge lamp, and a low power lighting mode, in which second electric power lower than the first electric power is supplied to the high pressure discharge lamp, by performing constant electric power control, thereby lighting the high pressure discharge lamp, wherein the electric supply device control unit is configured to, while in the low power lighting mode, (i) continuously supply a predetermined base current to the high pressure discharge lamp, (ii) send a current supply command signal so that boost current, which is obtained by superimposing current having a predetermined magnitude on the base current, is periodically supplied to the high pressure discharge lamp, and (iii) send a luminance control signal to adjust the luminance of a video signal of the liquid crystal projector apparatus according to a magnitude of operation power of the high pressure discharge lamp, which is operated responding to the supply of the boost current.