in a character imaging system , a selected one of a plurality of different characters arrayed as windows in an otherwise opaque mask , is projected optically onto a selected location on a working surface . in this manner , laser light can be used to burn an impression into a workpiece , with successive characters spelling out words and sentences . alternatively , the system can be used to project non - coherent light onto photographic film or onto a screen . the improvement in this type of system provided by the invention resides in the avoidance of a need to move the mask , or the working surface , or the final lens that projects the light beam onto such surface . and yet the improved system nevertheless enables sequential selection of different characters in the mask , as necessary to build up words and sentences on the working surface . this improvement is achieved by scanning a light beam that is projected onto an imaging element , while synchronously scanning mirrors that receive the imaged beam in such a manner that the final beam is projected onto the workpiece at a desired location regardless of which character - defining window in the mask is traversed by the beam .