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:
Dec. 05, 1989
Filed:
Dec. 23, 1987
Ki W Lee, Williamsburg, VA (US);
Charles R Cook Jr, Newport News, VA (US);
Siemens-Bendix Automotive Electronics L. P., Troy, MI (US);
Abstract
A mass airflow sensor is disclosed which uses a small, thin dielectric diaphragm providing good thermal isolation for thin-film heating and temperature sensing elements, resulting in high flow sensitivity and low current operation of the heating element. The dielectric diaphragm is bounded by a p-etch-stopped silicon rim. The mass airflow sensor includes a primary sensor circuit which maintains a heated primary temperature sensing element and an ambient air temperature sensing element at a constant temperature difference. A slave sensor circuit, which includes a plurality temperature sensing elements, monitors heat loss due to airflow at a particular location on the diaphragm and generates an output signal indicative of airflow which is independent of ambient air temperature.