The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 03, 2004
Filed:
Nov. 29, 2000
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A heat generation type flow sensor of an enhanced output sensitivity which is destined for use, for example, as an air flow sensor employed in an engine control system of a motor vehicle. The heat generation type flow sensor includes a silicon substrate ( ), a diaphragm ( ) disposed on the silicon substrate ( ) and having a cavity ( ) formed in a surface thereof, a flow rate detecting element ( ) provided on the diaphragm ( ) and including a heat generating resistor ( ) for outputting an electric signal indicative of a heating current flowing through the heat generating resistor ( ), a supporting member ( ) for supporting the flow rate detecting element ( ) on the diaphragm ( ) in such a deposition that one surface of the diaphragm ( ) is exposed to a fluid for measurement while the fluid for measurement is difficult to flow into the cavity ( ) formed in the other surface of the diaphragm ( ), and a control unit for performing such control that temperature of the heat generating resistor ( ) is sustained higher by a predetermined temperature than that of the fluid for measurement, wherein the heat generating resistor ( ) and the diaphragm ( ) are so dimensioned that ratio of a width of the heat generating resistor ( ) to that of the diaphragm ( ) is in a range from 0.4 to 0.6 inclusive and that ratio of a length (Yh) in a longitudinal direction of the heat generating resistor ( ) to that (Yd) of the diaphragm ( ) is in a range from 0.4 to 0.6 inclusive.