There is disclosed a quadrant detector which is characterized by an optical reflector immersed in a high refractive index material to increase the field of view of the detector. The immersed reflector divides the incoming radiation and directs varying portions of this radiation to four separate immersed...http://www.google.fr/patents/US4092531?utm_source=gb-gplus-shareBrevet US4092531 - Immersed reflector quadrant detector
