Surface parallelism alignment equipment - has telescope with double cross:hairs above surface reflector

摘要

The optical alignment equipment for checking surface parallelism consists of an optical bench (12) on which the specimen stands (10), and on which is a vertical stand (24) supporting a hinged feeler arm (18) which is placed on top of the specimen. The upper surface of the arm has a plane mirror reflector (19). Above the table is a viewer comprising an optical telescope with upper eye-piece (28) and object lens (29). Between the two lenses, is a target screen (51) fitted with cross-hairs and concentric rings. A second glass screen with a simple cross-hairs (31) is enclosed in a tubular housing on the lower end of the telescope. This housing is attached to an X-Y coordinate slide mechanism. Any non-parallelism between the surfaces of the specimen cause parallax error in the telescope viewer and indicated by non-coincidence of the two sets of cross-hairs.