An electret switch

Electrets were fabricated in a manner that the Teflon FEP film of 12 μm in thickness with one surface metallized was heated up to 140 °C and this surface was charged by corona. The attractive force and the repulsive force acting between the electret and the movable electrode caused by the surface charges a of the electret were measured. Electrets having a movable electrode of a hinge mechanism were fabricated by way of trial, and resultingly variations of the operating voltage and the returning voltage could be suppressed below about 30% after about a million cycles of operations were DC 150V applied.