Liquid crystal shutter for a lighting fixture

摘要

The present invention concerns a high intensity luminaire (15) for stage, theatre and architectural illumination, comprising: means for mounting a high intensity light source (35); an optical system for focusing light from a mounted high intensity light source through an exit aperture of the luminaire; a liquid crystal (LC) panel (70) mounted in the optical path of the luminaire; means for applying a variable voltage to said crystal panel; dichroic means (144) adapted to reduce the effect of heat generated in operation by the high light source on the operation of said panel; and means for controlling the contrast ratio of light emitted by said panel in response to variable ambient conditions; said control means comprising means for providing feedback to said panel either in response to the measured temperature of the panel or to measured contrast ratio of light transmitted through the panel.