Area-variable type capacitive displacement sensor having mechanical guide

An area-variable type capacitive displacement sensor, comprising:

• a stationary element having a stationary member, a first conductive pattern being formed on the stationary member;
• a movable element having a movable member, a second conductive pattern being formed on the movable member such that the second conductive pattern of the movable element faces the first conductive pattern of the stationary element, so that when the movable element moves in parallel to the stationary element, an overlapped area between the first and second conductive patterns is varied;
• an elastic member for providing a force biasing one of the stationary element and the movable member towards a remaining one thereof in a direction perpendicular to a driving direction so that the stationary element and the movable member are maintained in close contact with each other;
• a power supply for supplying power to one of the first and second conductive patterns of the stationary element and the movable member to generate an output signal depending on a variation in capacitance between the stationary element and the movable member;
• a signal detecting circuit connected to a remaining one of the first and second conductive patterns of the stationary element and the movable member to detect the variation in capacitance between the stationary element and the movable member and then output the variation in capacitance as an electric signal;
• and
• a guide means for correcting an initial alignment error and reducing an operation alignment error between the stationary element and the movable element.