GB911827A - Improvements in or relating to microscopes - Google Patents

Abstract

911,827. Microscopes. COOKE, TROUGHTON & SIMMS Ltd. Oct. 21, 1960 [Oct. 21, 1959], No. 35725/59. Class 97 (1). In a microscope having an arrangement as described in Specification 713,171 and comprising a concave reflecting surface which forms an image of the backfocal plane of the objective in the optical path between said surface and the eyepiece, said concave reflector surface is formed by the totally reflecting convex surface of a plano-convex lens mirror mounted with its plane surface towards the incident light. As shown in Fig. 3 light from a microscope objective and a lens 2 is directed by a plane reflecting surface 3a on to the plano-convex lens mirror 4 and thence, via a plane mirror 3b, to a lens 5 which re-images the intermediate image 7 of the object in the focal plane of the eyepiece (not shown). The mirror 4 forms at 8 an image of the backfocal plane of the microscope objective and in this plane are disposed diaphragms or polarizing filters so as to provide phase contrast, dark ground or differential colour effects. The diaphragms or filters are mounted on a slide whereby a selected diaphragm or filter may be interposed in the light path, this slide also being mounted on a rack whereby it may be moved in the direction of the optical axis so as to correctly position the slide in the image plane 8. The mirror 4 can be tilted with respect to the light incident thereon and the distance of this mirror from the intermediate image 7 determined by the actual thickness and refractive index of the mirror according to a table of data given in the Specification. In another form the two plane mirrors 3a and 3b may be formed by the adjacent surfaces of a prism.