Photosensitive device for indicating position and intensity with centrally located electrode

Claim 1

A LIGHT SENSITIVE DETECTOR COMPRISING AN ELEMENT HAVING TWO INTIMATELY UNITED LAYERS OF MATERIALS CHARACTERIZED BY HAVING DIFFERENT CONDUCTIVITY CHARACTERISTICS, ONE OF SAID LAYERS HAVING A SURFACE DEFINING AN OBSERVATION FIELD, A PLURALITY OF PAIR OF ELECTRODES ATTACHED TO SAID ONE LAYER IN POSITIONS SPACED ABOUT THE FIELD OF OBSERVATIONS MEANS FOR FOCUSING LIGHT FROM A REMOTE LIGHT SOURCE INTO A SPOT ON SAID ONE LAYER IN THE OBSERVATION FIELD, MEANS CONNECTED BETWEEN SELECTED PAIR OF SAID ELECTRODE INCLUDING MEANS FOR SENSING ELECTRIC SIGNALS THAT VARY IN RESPONSE TO THE LOCATION IN THE OBSERVATION FIELD WHERE THE LIGHT SPOT IMPINGES RELATIVE TO THE SAID SELECTED PAIR OF ELECTRODES, ANOTHER ELECTRODE ATTACHED TO THE ELEMENT LAYER ON THE OPPOSITE SIDE OF THE ELEMENT, SAID OTHER ELECTRODE BEING CENTRALLY LOCATED RELATIVE TO THE OBSERVATION FIELD, AND MEANS FOR MEASURING THE INTENSITY OF THE LIGHT SPOT IMPINGING ON THE OBSERVATION FIELD CONNECTED BETWEEN SAID OTHER ELECTRODE AND AT LEAST ONE OF THE AFORESAID SPACED ELECTRODES, SAID INTENSITY MEASURING MEANS INCLUDING MEANS SENSING SIGNAL THAT VARY IN RESPONSE TO THE INTENSITY OF THE LIGHT SPOT IMPINGING ON THE OBSERVATION FIELD.