Patent ID: 8356521

Claim:
A pressure sensor device, comprising: a substrate having a first section and a second section being adjacent to the first section and thinner than the first section; a piezoelectric film having flexibility and disposed on the second section; an upper electrode formed on the piezoelectric film and including: a center electrode disposed at a substantially center of the second section in plan view; and a peripheral electrode disposed apart from the center electrode so as to surround the center electrode; a lower electrode formed between the second section and the piezoelectric film and disposed so as to face the upper electrode; and a detection circuit including a differential circuit electrically connected to the center electrode and the peripheral electrode, wherein the detection circuit detects a difference between a first voltage caused between the center electrode and the lower electrode in response to the piezoelectric film being distorted, and a second voltage caused between the peripheral electrode and the lower electrode in response to the piezoelectric film being distorted, and a first polarity of a first charge generated in the center electrode in response to the piezoelectric film being distorted is different from a second polarity of a second charge generated in the peripheral electrode in response to the piezoelectric film being distorted.