US 2007/0164688 A1 · DISCHARGE LAMP IGNITION DEVICE AND PROJECTOR

Abstract

To avoid the phenomenon of unsightly flickering in images projected by the projector, in high pressure discharge lamps—especially in high intensity discharge lamps, such as high pressure mercury lamps, metal halide lamps, and xenon lamps—that are used in projectors, even in the presence of the phenomenon of cyclical modulation of the lamp voltage by the returning the light spectrum when the light reflected by the dynamic color filter returns back through the optical system to the lamp, at least during steady operation of the discharge lamp (Ld), a target lamp current signal generation circuit (Up) acquires multiple lamp voltage detection signal (Sv) over a period that is at least as long as the color order cycle of the dynamic color filter (Of) and generates a target lamp current signal (St) based on the multiple lamp voltage detection signals (Sv) that were acquired.

Claims17

Dependent claims

A discharge lamp ignition device for starting and lighting a discharge lamp in a projector that projects and displays images using a dynamic color filter to replace the luminous flux produced by the discharge lamp with a color ordered luminous flux, comprising:

a feeder circuit to supply power to the discharge lamp,
a voltage detection means that detects the voltage of the discharge lamp and generates a lamp voltage detection signal,
a current detection means that detects the current of the discharge lamp and generates a lamp current detection signal,
a target lamp current signal generation circuit that acquires the lamp voltage detection signal and generates a target lamp current signal, and
a feeder capacity control circuit that provides feedback control of the feeder circuit so as to minimize any disparity between the target lamp current signal and the lamp current detection signal,
wherein, at least during steady operation of the discharge lamp, the target lamp current signal generation circuit is adapted to acquire multiple lamp voltage detection signals over a period of time that is at least as long as a color order cycle of the dynamic color filter and then generate the target lamp current signal on the basis of the multiple lamp voltage detection signals that were acquired.

3 more elements

A method of starting and lighting a discharge lamp in a projector that projects and displays images using a dynamic color filter to replace the luminous flux produced by the discharge lamp with a color ordered luminous flux, using a discharge lamp ignition device comprising:

a feeder circuit to supply power to the discharge lamp,
a voltage detection means that detects the voltage of the discharge lamp and generates a lamp voltage detection signal,
a current detection means that detects the current of the discharge lamp and generates a lamp current detection signal,
a target lamp current signal generation circuit that acquires the lamp voltage detection signal and generates a target lamp current signal, and
a feeder capacity control circuit that provides feedback control of the feeder circuit so as to minimize any disparity between the target lamp current signal and the lamp current detection signal,
wherein, at least during steady operation of the discharge lamp, the target lamp current signal generation circuit acquires multiple lamp voltage detection signals over a period of time that is at least as long as a color order cycle of the dynamic color filter and then generates the target lamp current signal on the basis of the multiple lamp voltage detection signals that were acquired.

3 more elements

Dependencies are inferred from the claim text.

Discharge lamp ignition device and projector

Life of this patent

Discharge lamp ignition device and projector

Life of this patent

Abstract

Claims17