Patent ID: 6842015

Claim:
A capacitance type sensor comprising: a substrate for determining an XY plane in a defined XYZ three-dimensional coordinate system; a detective member being opposite to said substrate; a conductive member disposed between said substrate and said detective member, said conductive member being displaceable in a Z-axis direction as said detective member is displaced in a Z-axis direction; a reference electrode formed on said substrate and electrically connected with said conductive member, said reference electrode being grounded or kept at a fixed potential; a first electrode formed on said substrate; a second electrode formed on said substrate to constitute a first capacitance element with said conductive member; and a third electrode disposed at a distance from said first electrode so that said third electrode can be brought into contact with said first electrode as said conductive member is displaced, wherein: the displacement of said detective member on the basis of a detection, using a signal input to said second electrode, of a change in capacitance value of said first capacitance element caused by a change in distance between said conductive member and said second electrode, and a judgment as to whether said first and third electrodes are in contact with each other, can both be recognized, and during the displacement of said detective member toward said conductive member, said conductive member starts to displace toward said second electrode before said first and third electrodes are brought into contact with each other.