Patent ID: 8169210

Claim:
A contactless system for sensing electrostatic potential on a chargeable surface comprising: a first circuit for charging the chargeable surface to receive and hold a first voltage charge; a scanner probe having a probe surface, the probe surface being displaced a distance from the chargeable surface; second circuit for biasing the scanner probe to a scanner probe bias voltage within a predetermined voltage threshold of the first voltage charge; a capacitor formed of the chargeable surface, a dielectric material between the scanner probe surface and the chargeable surface, and the scanner probe surface, wherein the scanner probe senses a potential associated with an applied charge on the chargeable surface; a device for inducing an oscillating current in the scanner probe that results in the scanner probe vibrating; a third circuit for sensing the vibration-induced oscillating current in the scanner probe; a processor; and a charge determination module including programmable instructions executable by the processor for determining a potential of a specific location on the chargeable surface based on the scanner probe reading and the vibration-induced oscillating current in the scanner probe, including charge migration on the chargeable surface, and adjusting the scanner probe bias voltage to null the vibration-induced oscillating current in the scanner probe.