Brightness shutter for image projectors

摘要

The shutter can be so moved into the projector beam path that the originally unobstructed light flux is reduced gradually up to full blocking without need to move the projection screen or to change its colour. The shutter is optically widely spaced from the object and image plane on insulation. It comprises an intermediate zone in the region of the gradual light flux reduction, in which the transparency against the movement direction is almost uniformly reduced. Pref. the shutter is inserted between the projection lamp and transparency.