Improvements in and relating to an arrangement for projecting in superposition the images of a work piece and of a reference drawing through an outline projector

摘要

747,680. Optical projection gauges. SOC. GENEVOISE D'INSTRUMENTS DE PHYSIQUE. July 7, 1953 [July 17, 1952], No. 18779/53. Class 106 (2). [Also in Group XX] A reference drawing is projected by the same objective as the outline of an object and with the same magnification, the illumination of the object being episcopic or diascopic. In the form shown the object 1 on a transparent plate 2 is illuminated diascopically by a system 4 and a graticule 6 carrying the reference drawing is illuminated by the system 5. The two beams are combined by a semi-reflecting mirror 7 and superposed projected images are produced by the objective 3. The housing 10 for the mirror 7 and graticule 6 may be rotated through 180 degrees to produce episcopic illumination of the object by light from the system 5 reflected from the upper surface of the mirror 7, the graticule being illuminated by the transmitted light and being backed by a detachable plane mirror. The mirror 7 may be replaced by a pair of rightangled prisms with a semi-reflecting surface at their contacting hypotenuse faces.