Patent ID: 6388279
Filing Date: 2002-05-14
Classification: B81C,G01L

Abstract:
A semiconductor pressure sensor comprising:a diaphragm which deflects in response to pressure acting on a main surface thereof; a pressure reference chamber provided on a side of a rear surface of the diaphragm, an inside of the pressure reference chamber being in a state of reduced pressure; and a detecting device for detecting the pressure acting on the main surface of the diaphragm based on an amount of deflection of the diaphragm, wherein, a thickness of the diaphragm is set so that a maximum value of deflection of the diaphragm which is derived from a thickness, a side length, an elastic modulus determined from a material of the diaphragm and a pressure uniformly acting on the main surface of the diaphragm is equal to or lower than the thickness of the diaphragm, and the maximum value W (mm) of deflection of the diaphragm is expressed by the following equation, W=0.014Ã—(PÃ—L4)/(EÃ—H3) in which P (kgf/mm2) is a pressure acting on the diaphragm which is determined by a difference between a pressure Po (kgf/mm2) acting on the main surface thereof and a pressure Ps (kgf/mm2) acting on the rear surface thereof, L (mm) is a side length of the diaphragm having a square shape, E (kfg/mm2) is an elastic modulus determined by the material and H is a thickness dimension of the diaphragm.