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:
Oct. 09, 1984
Filed:
Jun. 30, 1982
Robert Bosch GmbH, Stuttgart, DE;
Abstract
An etched metal membrane has its rim laser-welded or electron-beam-welded to a ring made of the same kind of metal within which a central electrode is held by a metal-to-glass seal. The welding is done in vacuum to avoid the necessity of later evacuation. The pressure sensor capacitance thus formed is connected through an impedance converter to an oscillator circuit which provides an output frequency that varies with the sensed pressure. The inner surface of the central electrode is flush with the surface of the rim to which the membrane is welded to reduce variations in capacitance of the sensor, and any residual variations are compensated by a resistance balance in the evaluation circuit. The insensitivity of the system to temperature and its service life make it suitable for sensing the intake air pressure of an internal combustion engine.