Light gun with coaxially positioned elements

Claim 1

PHOTO-OPTICAL TRANSDUCER APPARATUS COMPRISING, (A) A DEMOUNTABLE SOURCE OF ILLUMINATION, (B) A CONDENSER LENS HAVING AN AXIAL BORE THERETHROUGH, (C) A LENTICULAR OPTICAL ELEMENT LIKEWISE PROVIDED WITH AN AXIAL BORE INTEGRAL WITH SAID CONDENSER LENS, (D) A TARGET FIELD LENS HAVING A CONVEX PORTION THEREON, (E) A PHOTOCELL, (F) MEANS MOUNTING SAID PHOTOCELL INTERMEDIATE SAID CONDENSER LENS AND THE CONVEX PORTION OF SAID TARGET FIELD LENS WITH ONE END OF SAID MOUNTING MEANS DISPOSED AXIALLY THROUGH SAID BORE IN SAID CONDENSER LENS AND THE OPPOSITE END OF SAID MOUNTING MEANS STRADDLING SAID CONVEX PORTION OF SAID TARGET FIELD LENS, (G) MEANS ADJACENT SAID TARGET FIELD LENS AND SAID PHOTOCELL MOUNTING MEANS PROVIDING AN APERTURE THROUGH WHICH PASSES LIGHT FROM SAID SOURCE, (H) AN OBJECTIVE LENS, AND (I) MEANS ADJUSTABLY MOUNTING SAID OBJECTIVE LENS FOR RELATIVE MOVEMENT WITH RESPECT TO SAID TARGET FIELD LENS WHEREBY LIGHT FROM SAID SOURCE IS FOCUSED THROUGH SAID APERTURE AND SAID OBJECTIVE LENS ONTO A TARGET AREA AND DIRECT LIGHT FROM SAID TARGET AREA IS FOCUSSED BACK THROUGH SAID CONVEX PORTION OF SAID TARGET FIELD LENS ONTO SAID PHOTOCELL EFFECTIVE TO PRODUCE A SIGNAL OUTPUT THEREFROM.