Pressure sensor

US4382247A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Gunther Stecher · Ludwigsburg, DE
• Kurt Spitzenberger · Laichingen, DE
• Klaus Muller · Tamm, DE

Key dates

• Filing date: Aug 27, 1980
• Grant date: May 3, 1983
• Expiry date: Aug 27, 2000

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L9/0075
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A deformable membrane is made by applying, by thick-film technology, a glass-ceramic paste over a vaporizable or burnable filler material, containing primarily carbon black in a binder which, in turn, is located on a substrate, for example of ceramic, glass, enameled metal or the like. The substrate for example is about 1.5 cm square, the membrane glass ceramic being applied as a circular dot of about 0.5 cm diameter. After solidifying the paste forming the membrane in a protective gas atmosphere, for example at about 950.degree. C., the filler is burned out in an oxidizing atmosphere, to escape through pores in the membrane material. By selecting a membrane material which has a lower thermal coefficient of expansion than that of the substrate, after burning, the membrane will assume a convex shape leaving a hollow space (8) beneath it and the substrate. The membrane is pressure-sensitive, for example when a predetermined quantity of a predetermined gas under a predetermined pressure is sealed therein, or if access to the interior of the space is provided through the substrate, for example by a tiny duct which is connected to a flange or stub connection. Electrical output can be ob…