Laser read-write system for the production of engravings

Abstract From the Canadian patent

Engraving apparatus with particular reference to a plate to be engraved having a photosensitive surface in which a write laser beam exposes ? surface by scanning the same in conjunction with a read optical path associated with a copy board positioned proximate the plate. Means for example, such a read laser beam scans the copy board, the reflection therefrom being noted and used to control the intensity of the write beam. The optical scanning elements of both the read optical path and the write beam are common to each so that positional error due to vibrations in the optical components is eliminated. Provision is made for read-right conversion to read-wrong during preparation of a plate, …