Optical distance detecting devices

Claim 1

A DISTANCE SENSITIVE DEVICE WHICH COMPRISES, IN COMBINATION, A CASING, AN OBJECTIVE CARRIED BY SAID CASING AND CAPABLE OF FORMING, IN A GIVEN IMAGE PLANE HAVING A FIXED POSITION IN SAID CASING AND DIFFERENT FROM THE IMAGE FOCAL PLANE OF SAID OBJECTIVE, A SHARP REAL IMAGE OF ONLY OBJECTS LOCATED IN AN OBJECT PLANE CONJUGATE OF SAID IMAGE PLANE WITH RESPECT TO SAID OBJECTIVE AND LOCATED AT A GIVEN FINITE DISTANCE AHEAD OF SAID OBJECTIVE, AT LEAST ONE PAIR OF PHOTO-ELECTRIC ELEMENTS CARRIED BY SAID CASING INSIDE IT, SAID TWO PHOTO-ELECTRIC ELEMENTS HAVING EACH A LIGHT RECEIVING SURFACE, THE RESPECTIVE LIGHT RECEIVING SURFACES OF SAID TWO ELEMENTS BEING LOCATED IN SAID IMAGE PLANE SO AS TO RECEIVE SIMULTANEOUSLY THE LIGHT RAYS TRANSMITTED AT ANY GIVEN INSTANT THROUGH SAID OBJECTIVE, SAID TWO LIGHT RECEIVING SURFACES BEING AT A DISTANCE FROM EACH OTHER SMALLER THAN THE MINIMUM DISTANCE THAT CAN EXIST IN A BLURRED IMAGE BETWEEN A LIGHT POINT AND A DARK POINT THEREOF, ELECTRICAL MEANS HAVING INPUT TERMINALS AND OUTPUT TERMINALS FOR PRODUCING A SIGNAL ACROSS SAID OUTPUT TERMINALS IN RESPONSE TO A VOLTAGE DIFFERENCE PRODUCED ACROSS SAID INPUT TERMINALS, AND MEANS FOR CONNECTING