Patent ID: 6675644
Filing Date: 2004-01-13
Classification: G01F

Abstract:
A thermo-sensitive flow rate sensor for measuring a flow rate of a fluid, said thermo-sensitive flow rate sensor comprising:a plate-like substrate having a central portion which is removed so that a cavity is provided therein; a diaphragm portion formed by a thin layer disposed above said cavity in such a manner as to be integral with said plate-like substrate; a heating element formed by a thermo-sensitive electrically resistant film disposed on said diaphragm portion; a temperature measuring element, spaced apart from said diaphragm portion and formed on said plate-like substrate, for detecting a temperature of said fluid to be measured; and a control circuit for controlling a heating current to be supplied to said heating element so that a temperature of said heating element is higher than a temperature of said fluid by a predetermined number of degrees, thereby measuring a flow rate of said fluid according to the heating current for said heating element, wherein a plurality of holes are provided in an outer peripheral portion of said diaphragm portion which is other than a part located upstream of said heating element so as to penetrate said diaphragm portion.