Photo-electrical sensitometric measuring apparatus

Claim 1

AN ILLUMINATING OPTICAL MEASURING HEAD FOR USE WITH PHOTOMETRIC INSTRUMENTS, AND PARTICULARLY DENSITOMETERS, IN TRANSMISSION AS WELL AS REFLECTION DENSITY MEASUREMENTS OF A SPECIMEN STRIP UNDER INVESTIGATION, COMPRISING A SUPPORT HAVING AN APERTURE, MEANS FOR HOLDING SAID STRIP ON SAID SUPPORT AND OVER SAID APERTURE, A FIRST ELECTRIC LIGHT SOURCE MOUNTED BELOW SAID SUPPORT AND TO ONE SIDE OF SAID APERTURE, OPTICAL MEANS FOR DIRECTING THE LIGHT THEREFROM IN A DIRECTION PERPENDICULAR TO SAID SUPPORT AND AT SAID APERTURE, A SECOND ELECTRIC LIGHT SOURCE MOUNTED ABOVE SAID SUPPORT, A CONCAVE ANNULAR MIRROR DISPOSED IN PARALLEL TO SAID SUPPORT AND SAID CONCAVE ROUND SAID SECOND LIGHT SOURCE, A CONICAL ANNULAR MIRROR DISPOSED IN PARALLEL TO SAID SUPPORT AND SAID CONCAVE ANNULAR MIRROR AND INTERPOSED BETWEEN SAID CONCAVE MIRROR AND SAID SUPPORT IN CONCENTRIC ALIGNMENT WITH SAID CONCAVE MIRROR, A WALL PERPENDICULAR TO SAID SUPPORT AND ON THE SIDE OF SAID ANNULAR MIRRORS ABOVE SAID FIRST LIGHT SOURCE, AN EXIT OPENING IN SAID WALL, A LIGHT DEFLECTING ELEMENT INTERPOSED BETWEEN SAID SUPPORT AND SAID SECOND LIGHT SOURCE AND INCLUDING A FIRST TUBULAR PORTION EXTENDING THROUGH SAID CONICAL ANNULAR MIRROR AND DISPOSED PERPENDICULAR TO SAID SUPPORT AND IN COAXIAL RELATIONSHIP TO SAID APERTURE AND SAID ANNULAR MIRRORS, AND A SECOND TUBULAR PORTION EXTENDING AT RIGHT ANGLE TO SAID FIRST TUBULAR PORTION AND IN PARALLEL TO SAID SUPPORT AND SAID ANGULAR MIRRORS, TOWARD SAID EXIT OPENING, AND A PHOTOTUBE MOUNTED ON THE SIDE OF SAID WALL, IN THE PATH OF LIGHT PASSING THROUGH SAID EXIT OPENING, WHEREBY LIGHT EMITTED BY SAID FIRST LIGHT SOURCE AND FOCUSSED ON THE APERTURE FROM BELOW, FOR TRANSILLUMINATION OF THE SPECIMEN HELD OVER SAID APERTURE, AS WELL AS LIGHT EMITTED BY SAID SECOND LIGHT SOURCE AND FOCUSSED, BY MEANS OF SAID ANNULAR MIRRORS, ON THE APERTURE FROM ABOVE, FOR REFLECTION FROM THE SPECIMEN, IS CONVEYED IN A SINGLE BEAM THROUGH SAID DEFLECTING ELEMENT AND SAID EXIT OPENING ON TO SAID PHOTOTUBE.