Polarizing microscope having bertrand lens

Claim 1

A polarizing microscope operable in conoscopic and orthoscopic modes comprising in combination: a source of light; a polarizer for directing the polarized light rays along a predetermined path to an object plane; an objective means in optical alignment along a common optical axis for focusing said polarized light rays coming from said object plane for producing an image; an ocular means in said path for observation of the image; a Bertrand lens insertable in said path between said objective and ocular means; a diaphragm means disposed in said path and insertable with said Bertrand lens, the diaphragm means being physically adjacent thereto; the diaphragm means and Bertrand lens being insertable during said conoscopic mode; an analyzer disposed in said path of the focused light between said ocular means and said Bertrand lens for controlling the polarized light transmitted toward said ocular means; an additional lens means insertable in said path between said objective and Bertrand lens during said conoscopic mode; the focal length of said additional lens means selected to produce an image of the object in the plane of said diaphragm means, whereby the object remains in focus between the orthoscopic and conoscopic modes.