Shutterless cine camera and projector - use rotating disc mirror with surface shaped so that reflected image has constant place w.r.t. frames on moving film

摘要

The light coming through the lens is projected on to the film by a rotating disc mirror, whose surface is so shaped that the reflected image keeps the same plate w.r.t. frames on the moving strip of film. Along one radius of the disc there is a step (elsewhere the gradient changes continuously). When the light from the lens crosses this step, a new, separate image is formed on the film. The disc rotation is synchronised with the film movement (which may be very fast), but neither a shutter nor a sprocket drive is required. Only a sector of the disc need be used (the pictures are then separated by time intervals). Conversely, the whole gradient can be contained in a sector, and several such sectors contained within the circle (then several film frames correspond to a single rotation of the disc).