Improvements in or relating to illuminating devices for episcopic projection apparatus

摘要

559,971. Optical-projection apparatus. SOC. GENEVOISE D'INSTRUMENTS DE PHYSIQUE. Sept. 10, 1942, No. 12764. Convention date, Jan. 28. [Class 97 (i)] In episcopic projection apparatus, means for producing perpendicular illumination of the object, and means producing oblique illumination of the object, are so mounted that either may be brought into operative position. As shown in vertical section in Fig. 2, and in plan in Fig. 4, a semi-transparent plate 6 and mirrors 7, 8 are mounted on a slide 9 movable rectilinearly on a collar 18, carried by the tube 2 around an objective 1, to bring either the plate or mirrors into position beneath an object 4 on a table 3. The plate 6 is adjustable in inclination to reflect a parallel beam from an external source perpendicularly on to the surface of the object 4. The mirrors 7, 8 are adjustable towards and from one another, and in inclination, to effect light ground or dark ground illumination by a beam from the external source, details of construction of such means, and of stops for limiting the movements, being described. A modification is described in which the slide 9 is replaced by a plate rotatable about a spindle having its axis parallel to the optical axis of the objective.