Light source having automatically variable hue, saturation and beam divergence

摘要

A variable light source includes a light (14) which projects a white light beam. Three filters sets (60, 62 and 64) each include three pivotable dichroic filter elements. Each element is rotatable around an axis perpendicular to the light beam in order to vary the angle of incidence to vary the hue of the light beam. Rotation of the filter elements also varies the white light transmitted past the filter elements in order to vary the saturation of the light. The distance between the light source (26) and the reflector (28) may be varied to change the divergence of the light beam.