Two color background elimination detector

Claim 1

TWO COLOR BACKGROUND ELIMINATION DETECTOR APPARATUS COMPRISING, IN COMBINATION, FIRST DETECTOR MEANS, SECOND DETECTOR MEANS DISPOSED ADJACENT THE FIRST DETECTOR MEANS AND ELECTRICALLY INSULATED THEREFROM, RADIANT ENERGY FROM THE SUN AND A TARGET SOURCE ARRIVING AT THE SECOND DETECTOR MEANS ONLY AFTER PASSING THROUGH THE FIRST DETECTOR MEANS, SAID SECOND DETECTOR MEANS GENERATING A SIGNAL IN RESPONSE TO ENERGY LYING IN A PREDETERMINED BAND OF THE SPECTRUM OF ENERGY LYING IN A PREDETERMINED EMITTED BY THE TARGET SOURCE ALSO LYING IN SAID BAND, THE FIRST DETECTOR MEANS ABSORBING RADIANT ENERGY OVER A PORTION OF SAID BAND AND GENERATING A SIGNAL WHILE ENERGY IN SAID PORTION IS ABSORBED THEREBY, THE RADIANT ENERGY FROM THE TARGET SOURCE LYING OUTSIDE OF SAID PORTION, SAID FIRST DETECTOR MEANS PASSING TO THE SECOND DETECTOR MEANS RADIANT ENERGY IN THE REMAINDER OF SAID BAND OUTSIDE OF SAID PORTION WHICH ARRIVES AT THE FIRST DETECTOR MEANS, SAID SECOND DETECTOR MEANS BEING RESPONSIVE TO THE PASSED RADIANT ENERGY AND GENERATING A SIGNAL WHILE ENERGY IN SAID REMAINDER IMPINGES THEREON, SIGNAL CANCELLATION MEANS, AND MEANS FOR APPLYING THE SIGNALS DEVELOPED BY THE FIRST DETECTOR MEANS AND THE SECOND DETECTOR MEANS IN PHASE OPPOSITION TO THE SIGNAL CANCELLATION MEANS, THE SIGNAL CANCELLATION MEANS BEING ADJUSTABLE IN A MANNER WHEREBY SIGNAL COMPONENTS OF THE FIRST AND SECOND DETECTOR MEANS PROVIDED BY RADIATION FROM THE SUN ARE BALANCED OUT IN THE SIGNAL CANCELLATION MEANS AND ONLY A SIGNAL COMPONENT RESULTING FROM RADIANT ENERGY FROM THE TARGET SOURCE STRIKING THE SECOND DETECTOR MEANS PROVIDES A SIGNAL OUTPUT.