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:
Mar. 20, 1990
Filed:
Oct. 14, 1987
Fred C Sittler, Excelsior, MN (US);
James H Crabtree, Long Beach, CA (US);
Rosemount Inc., Eden Prairie, MN (US);
Abstract
A thermal effect sensing device comprises a semiconductor substrate supporting an insulating layer which has a thin film of platinum deposited on it. Holes are etched through the semiconductor substrate and the insulating layer. The platinum film is shaped to provide a serpentine resistive element suspended over one of the holes. The serpentine element is suspended from the rim of the hole, but is otherwise unsupported. The resistive element has a low thermal mass and there is a low thermal resistance between the element and fluid in the sensor. The sensor senses thermal properties of the fluid in the sensor, such as mass flow or thermal conductivity. A second conductive film is insulatingly deposited on the first film to provide a resistive sensor electrically isolated from a resistive heating element.