Patent ID: 7243545

Claim:
A physical quantity sensor for detecting physical quantity, the sensor comprising: a plurality of springs; a fixed electrode; and a movable electrode connecting to the springs, wherein the springs are movable in accordance with the physical quantity, wherein the fixed electrode and the movable electrode provide a capacitor having a capacitance therebetween so that the physical quantity is detectable on the basis of the capacitance, wherein the springs have different spring constants, respectively, wherein each of the springs is movable in accordance with the corresponding spring constant when the physical quantity is applied to the sensor, wherein the springs include a long spring and a short spring, wherein the long spring includes a pair of long beams, which provide a first loop with a beam distance between the long beams, wherein the short spring includes a pair of short beams, which provide a second loop with a beam distance between the short beams, wherein the springs further include a stopper, which is supported by the short spring, wherein the long spring is configured to be displaceable when the physical quantity is smaller than a predetermined value, wherein displacement of the long beam is limited by the stopper and the short spring is configured to be displaceable when the physical quantity is equal to or larger than the predetermined value.