Patent ID: 7132722
Filing Date: 2006-11-07
Classification: G01P

Abstract:
1. A physical quantity sensor comprising: a substrate; an insulating film having an opening, which is formed to partially expose a main surface of the substrate; a plurality of piezoelectric sensors each having two terminals, wherein each piezoelectric sensor is constituted such that a sensing portion thereof is arranged in the opening while being supported by the two terminals attached onto the insulating film at different positions in a periphery of the opening, and wherein each piezoelectric sensor comprises a first semiconductor layer having a coil-like winding pattern that is elongated from the periphery of the opening of the insulating film inwardly into the opening, a second semiconductor layer having a coil-like winding pattern that is elongated from the periphery of the opening of the insulating film inwardly into the opening, and a conductive weight portion that mutually connects internal ends of the first and second semiconductor layers in the opening, whereby external ends of the first and second semiconductor layers attached onto the insulating film are used to form the two terminals, and the conductive weight portion is supported by the first and second semiconductor layers in a floating manner in the opening so as to realize three-dimensional displacement therewith; and a capacitance electrode layer, which is arranged in a bottom of the opening on the main surface of the substrate so as to establish capacitance between the capacitance electrode layer and the conductive weight portion, whereby the displacement of the conductive weight portion is detected based on variations of resistances of the first and second semiconductor layers and variations of the capacitance.