Area-varying capacitive sensor, and self compensation and signal linearization method thereof

Abstract

An area varying capacitive sensor for substantially reducing a drift and an offset without performing a complicated process by linearizing a signal while automatically compensating the offset and the drift by additionally disposing an electrode and performing a simple signal process without applying complicated signal processing to an area varying capacitive sensor having a periodic electrode, a self compensation and signal linearization method of the area varying capacitive sensor are provided. A self compensation and signal linearization method of the sensor having four electrode sets that are disposed to generate a phase difference signal of 90 degrees comprises: controlling the four electrode sets to respectively output a signal with a phase difference of 90 degrees; acquiring two signals from which common signal components including a drift and an offset are eliminated by subtracting the signals that have opposite phases from among the signals that are output by the four electrode sets; controlling peak values of the two signals from which the common signal components are eliminated to have the same size, and acquiring two signals from which absolute values are taken; and comparing sizes of the two signals from which the absolute values are taken, taking a lesser value, and acquiring a linearized triangular wave.