Dual high-pressure discharge lamp projector with multi-waveform current generation for greater luminous flux change control and extended lamp life

摘要

The projector uses two lamps, which are high-pressure discharge lamps with the same rated power, as light sources. The projector includes: a first alternating-current generator configured to generate a lamp current to be supplied to one of the lamps, based on an input control signal; a second alternating-current generator configured to generate a lamp current to be supplied to the other lamp, based on an input control signal; and a controller configured to control the lamp currents to have a same period and to be out of phase, by inputting a control signal to each of the first and the second alternating-current generators.

主权项

1. A projector using first and second high-pressure discharge lamps as light sources, each high-pressure lamp having an arc tube in which a pair of electrodes are disposed to face each other, the projector comprising:
a first alternating-current generator configured to generate a first alternating current to be supplied to the first high-pressure discharge lamp, a frequency of the first alternating current changing according to a first control signal; a second alternating-current generator configured to generate a second alternating current to be supplied to the second high-pressure discharge lamp, a frequency of the second alternating current changing according to a second control signal; and a controller configured to input the first and the second control signals to the first and the second alternating-current generators respectively, and thereby control the first and the second alternating currents to have a same waveform and to be out of phase, wherein the waveform of each of the first and the second alternating currents is composed of a first section, a second section, a third section, and a fourth section following each other in consecutive order, the first section consisting of a positive half-cycle of a first waveform having a first frequency, the second section consisting of one or more cycles of a second waveform having a second frequency, the third section consisting of a negative half-cycle of the first waveform having the first frequency, and the fourth section consisting of one or more cycles of the second waveform having the second frequency, and the first frequency being lower than the second frequency.