Air puff tonometer

Claim 1

A NON-CONTACTING TONOMETER COMPRISING A LIGHT SOURCE MEANS, A LIGHT DETECTOR FOR PRODUCING AN OUTPUT SIGNAL IN ACCORDANCE WITH THE LIGHT ENERGY IMPINGING THEREON, MEANS DEFINING A CONTROLLED OPTICAL PATH BETWEEN SAID LIGHT SOURCE MEANS AND SAID DETECTOR DEFINING A SENSING LIGHT BEAM, SAID OPTICAL PATH DEFINING MEANS INCLUDING MEANS DEFINING A SENSING ZONE INTO WHICH AN OBJECT UNDER TEST EXTENDS, SAID OPTICAL PATH BEING TRANSVERSE OF SAID SENSING ZONE WITH RESPECT TO SAID OBJECT WHEREAT SAID BEAM IS PARTIALLY OBSCURED BY SAID OBJECT, AND MEANS FOR DIRECTING A CALIBRATED PUFF OF AIR INTO SAID SENSING ZONE, SUBSTANTIALLY NORMAL TO SAID OPTICAL PATH THEREIN AND TOWARD THE SURFACE OF SAID OBJECT WHEREBY TO PRODUCE A MOMENTARY DEFORMATION OF SAID OBJECT IN ACCORDANCE WITH THE INTERNAL PRESSURE OF SAID OBJECT, SAID DEFORMATION OF SAID OBJECT PRODUCING A CORRESPONDING CHANGE IN THE OBSCURATION OF SAID BEAM WHEREBY TO PRODUCE A CHANGE IN SAID OUTPUT SIGNAL OF SAID DETECTOR IN ACCORDANCE WITH SAID DEFORMATION.