Photosensitive device to detect bearing deviation

Claim 1

A SENSING DEVICE FOR DETECTING THE DEVIATION OF A BODY ABOUT A PAIR OF AXES FROM A PREDETERMINED ATTITUDE WITH RESPECT TO A REMOTE LIGHT SOURCE COMPRISING: A PAIR OF PHOTOSENSITIVE MEMBERS ON SAID BODY SPACED ALONG A FIRST AXIS AND EACH MEMBER HAVING AN ELECTRICAL CHARACTERISTIC WHICH VARIES IN ACCORDANCE WITH THE ILLUMINATION THEREOF BY SAID LIGHT SOURCE, A THIRD PHOTOSENSITIVE MEMBER ON SAID BODY SPACED FROM SAID FIRST AXIS ALONG A SECOND AXIS NORMAL THERETO AND HAVING AN ELECTRICAL CHARACTERISTIC WHICH VARIES IN ACCORDANCE WITH ILLUMINATION THEREOF BY SAID LIGHT SOURCE, A LIGHT MASK FIXED ON SAID BODY AND INTERPOSED BETWEEN SAID MEMBERS AND SAID LIGHT SOURCE, A PAIR OF SPACED APART OPENINGS IN SAID LIGHT MASK AND ALIGNED WITH SAID PAIR OF PHOTOSENSITIVE MEMBERS, AND A THIRD OPENING IN SAID LIGHT MASK SPACED FROM SAID PAIR OF OPENINGS AND ALIGNED WITH SAID THIRD PHOTOSENSITIVE MEMBERS, A FIRST CIRCUIT MEANS FOR TRANSMITTING A SINGLE SIGNAL INDICATIVE OF A COMPARISON BETWEEN THE VALUES OF THE ELECTRIC CHARACTERISTICS OF SAID PAIR OF PHOTOSENSITIVE NENBERS UPON MOVEMENT OF SAID BODY ABOUT SAID SECOND AXIS, AND