Pick-up device detecting changes of the volume of mucous membranes in the mouth

Claim 1

A pickup device for sensing changes in the volume of mucous tissue membranes in the mouth comprising a holder adapted to be inserted within the mouth a first electrode comprising a flexible conductive plate adapted to conform to the shape of the portion of the mouth to be sensed, said first electrode being coated with an insulating material, at least two insulated members projecting from one side of said first electrode adapted to engage said mouth to space said first electrode a fixed distance from the tissue thereof, a second electrode secured exteriorly of said insulated coating on the other side of said first electrode for screening said first electrode, said second electrode being secured to said holder, means for connecting said first electrode to a live potential and said second electrode to ground, said first electrode and said mouth forming a capacitor, one plate of which is the first electrode, the other plate of which is the tissue of the mouth to be sensed and dielectric of which is the ambient air therebetween, and means electrically connected to said first electrode for sensing changes in capacitance.