A METHOD OF, AND AN APPARATUS FOR, WRITING MASK PATTERNS ON A PHOTOGRAPHIC MATERIAL, BY MEANS OF LIGTH.

摘要

WE CLAIM (1) A method of writing a mask pattern on photographic material, wherein the light from a source of light is projected through a slit means and onto the photographic material with an optical system, said slit means having two oppositely located boundaries which determine the length of the light spot incident on the photographic material in the direction of writing, characterized in that, one of said boundaries is moved at a variable rate in a path which corresponds to the mask pattern to be written, the other boundary being moved in correspondence with said one boundary after a constant time delay, so that the time elapsed between the forward and rear edges of the light spot past each infinitesimal element of the photographic material is the same.