A photometer for use with a microscope having an object plane an image plane and an optical axis between said planes. The photometer includes an optical dividing means adapted to be disposed in the optical axis between the microscope object and image planes, and a reflective element having a reflecting...http://www.google.se/patents/US4712889?utm_source=gb-gplus-sharePatent US4712889 - Photometer for use with a microscope
