Colour transparency projector using diffraction grating - blurs individual coloured stripes of discrete small colour particles

摘要

A colour transparency is used formed from discrete small particles each representing a colour of the scene and can be made from red, blue and gree dyes to form successive stripes of the three primary colours. Enlargement by projection on to a screen, however, renders visible the individual stripes, as well as dark lines at their edges. To correct this, the present appts. projects through a diffraction grating, pref. placed close against the projector's objective lens. - The grating overlays each colour component of a zero-order image with a first-order image deriving from elsewhere in the transparency. The grating may be a ruled, a transparent pulse phase or a sinusoidal grating.