Patent ID: 7137298
Filing Date: 2006-11-21
Classification: G01F

Abstract:
1. A thermal air flowmeter, comprising: a flat substrate constructed of a heat conducting material, on the surface of which an insulating film is disposed and a rectangular thermal insulating area is provided as a rectangular space; a heating element formed on said insulating film in said thermal insulating area; and two temperature detectors formed on both sides of said heating element on said insulating film in said thermal insulating area along the direction of air flow, wherein said thermal insulating area in said rectangular space is formed by etching said substrate, on the surface of which said insulating film is disposed, such that the length of the sides of said thermal insulating area parallel to the axis of air flow is greater than the length of the sides of said thermal insulating area perpendicular to the axis of air flow, wherein in the thermal insulating area, the area of the heating element is larger than the area of one of the temperature detectors.