Patent ID: 7464592

Claim:
A physical quantity sensor, comprising: a container; a sensing element installed in the container for detecting a physical quantity; and a viscous fluid that provides a damping when an external acceleration different from the physical quantity is applied to the sensor element; wherein: the sensing element is supported by the viscous fluid; a viscosity of the viscous fluid is controllable by applying a voltage having an electric field and a magnetic field associated therewith, the voltage proportional to a magnitude of the external acceleration, the voltage changing the viscosity such that when the external acceleration is increased, the viscosity is increased proportionally thereby increasing an effective stiffness of the sensing element; the sensing element includes a rectangular silicon-on-insulator (SOI) substrate having a beam structure, the beam structure including an oscillating body for detecting angular velocity, driving electrodes and detecting electrodes; and the driving electrodes are provided with driving comb teeth and the detecting electrodes are provided with detecting comb shaped teeth.