Patent ID: 7990159
Filing Date: 2011-08-02
Classification: G01R,G03G

Abstract:
1. A potential measurement apparatus for measuring a surface potential of an object of measurement, which is capable of detecting a change in electric charge induced at an detection electrode due to electrostatic induction by changing a distance between the detection electrode and the object of measurement in accordance with a predetermined period, using a neutral distance as reference, as a signal representing a change in electric current, comprising: a first detection unit for detecting a signal representing a fundamental period of the change in electric current and a signal representing a second harmonic period; a second detection unit for detecting information representing a capacitance between the detection electrode at the neutral distance and the object of measurement; and an arithmetic unit for making calculations according to a detection outcome of the first detection unit and a detection outcome of the second detection unit, the arithmetic unit computationally obtaining information on the surface potential of the object of measurement, with suppressing an component attributable to an influence of the neutral distance and the capacitance.