Patent ID: 7688204
Filing Date: 2010-03-30
Classification: B60N,B60R

Abstract:
1. A double-electrode capacitive sensor for detecting a detection object made of dielectric material, the sensor comprising: an electrode assembly having a first electrode, a second electrode and an insulation substrate; and a detection circuit electrically coupled with the first and second electrodes, wherein the first electrode faces the detection object, the first and second electrodes are overlapped, and the second electrode is coupled with a ground, the insulation substrate has a first surface and a second surface, the first electrode is disposed on the first surface, and the second electrode is disposed on the second surface, so that the second electrode faces the first electrode in parallel to the first electrode through the insulation substrate, the detection circuit applies an alternating voltage between the ground and one of the first and second electrodes, the detection circuit detects an electric potential of the other one of the first and second electrodes, or controls the electric potential of the other one of the first and second electrodes to follow the alternating voltage of the one of the first and second electrodes, the detection circuit detects a capacitance change between the first electrode and the ground when the detection object approaches the first electrode, the detection circuit determines whether the detection object approaches the first electrode based on the capacitance change, and the second electrode has a periphery, which is substantially opposite to a periphery of the first electrode.