Illuminating apparatus for a microscope system using polarized light

Claim 1

ILLUMINATING APPARATUS FOR A MICROSCOPE SYSTEM INCLUDING AN OBJECTIVE LENS, A REFLECTING SPECIMEN AND VIEWING MEANS WITH AN OPTICAL PATH PASSING THROUGH THE LENS BETWEEN THE SPECIMEN AND VIEWING MEANS, COMPRISING THE IMPROVED COMBINATION OF A SOURCE OF POLARISED LIGHT EXTERNAL TO SAID OPTICAL PATH, A SINGLE SEMI-TRANSPARENT REFLECTOR POSITIONED AT A POSITION ON THE OPTICAL PATH BETWEEN THE OBJECTIVE LENS AND THE VIEWING MEANS, MEANS INSERTING SAID POLARISED LIGHT INTO THE OPTICAL PATH FROM THE SOURCE IN A PATH TWICE PASSING THROUGH SAID POSITION, ONCE BY REFLECTION FROM THE SEMI-TRANSPARENT REFLECTOR AT AN ANGLE OF INCIDENCE NOT GREATER THAN 22.5* AND ONCE BY TRANSMISSION THROUGH THE SEMI-TRANSPARENT REFLECTOR, THEREBY ILLUMINATING THE SPECIMEN FOR OBSERVATION AT SAID VIEWING MEANS DURING PASSAGE THROUGH THE OPTICAL PATH, SAID SYSTEM CONSTITUTING OPTICAL ELEMENTS ARRANGED TO PASS THE POLARISED LIGHT FROM SAID SOURCE THROUGH THE OPTICAL PATH TO THE VIEWING MEANS WITHOUT SIGNIFICANT ROTATION.