Apparatus for indicating presence of predetermined color in sample

Claim 1

COLOR DETECTING AND SIGNALING APPARATUS FOR PROVIDING A FIRST CHARACTERISTIC SIGNAL WHENEVER THE OBSERVED COLOR OF A SAMPLE FALLS ANYWHERE WITHIN A SHARPLY DEFINED COLOR ELEMENT AND FOR PROVIDING ANOTHER CHARACTERISTIC SIGNAL AT ALL OTHER TIMES, COMPRISING A PLURALITY OF PHOTOELECTRIC TRANSDUCERS, EACH RESPONSIVE TO A CHROMATICALLY DIFFERING COMPONENT OF LIGHT FROM A SAMPLE AND EACH PROVIDING A SEPARATE OUTPUT WHICH VARIES SUBSTANTIALLY IN ACCORDANCE WITH THE INTENSITY OF THE ASSOCIATED SAID CHROMATIC COMPONENT RECEIVED FROM SAID SAMPLE, MEANS FOR APPLYING LIGHT FROM SAID SAMPLE TO EACH OF SAID TRANSDUCERS, A SEPARATE BAND PASS CIRCUIT CONNECTED TO RECEIVE THE OUTPUT OF EACH OF SAID TRANSDUCERS AND EACH HAVING A BAND PASS THE WIDTH OF WHICH EFFECTIVELY DEFINES ONE DIMENSION OF SAID COLOR ELEMENT AND THE ACCEPTANCE LEVEL OF WHICH IN RELATION TO THE OUTPUT OF THE ASSOCIATED SAID TRANSDUCER DEFINES THE POSITION OF SAID COLOR ELEMENT IN THE CORRESPONDING DIMENSION OF COLOR SPACE AND EACH OPERABLE TO PROVIDE AN OUTPUT WHICH REMAINS SUBSTANTIALLY INVARIANT AS LONG AS THE INPUT THERETO FROM THE ASSOCIATED TRANSDUCER REMAINS WITHIN SAID PASS BAND, AND A COINCIDENCE CIRCUIT HAVING SEPARATE INPUTS EACH CONNECTED RESPECTIVELY TO RECEIVE THE OUTPUT OF ONE OF SAID BAND PASS CIRCUITS AND OPERABLE TO FORM SAID FIRST SIGNAL UPON THE OCCURRENCE OF SIMULTANEOUS OUTPUTS FROM EACH OF SAID BAND PASS CIRCUITS SIGNALING THE OCCURRENCE OF A COLOR FROM SAID SAMPLE SOMEWHERE WITHIN SAID COLOR ELEMENT AND FURTHER FORMING SAID ANOTHER SIGNAL AT ALL OTHER TIMES INDICATING THE ABSENCE OF COLOR FROM SAID SAMPLE WITHIN SAID COLOR ELEMENT.