Robert Boschgmbh

Kurt Spitzenberger

Gunther Stecher

Herbert Zimmermann

Klaus D Muller

Wolfgang Leibfried

Klaus Steinle

Hans Hecht

Guenther Stecher

Heinz Walter

Manfred Nitsch

Fedor Modic

Hans J Glas

Alfred Grob

Karl Rampmaier

Cicuit and process of manufacturing the circuit

High pressure sensor

A pressure measuring element includes a plate-shaped substrate of ceramic material and a membrane deformable in response to pressure fluctuations. The membrane is made of ceramic material and is mounted to the upper side of the substrate. A pressure-sensitive resistor for measuring pressure is positioned inside the membrane. A heating resistor element is positioned on the underside of the substrate, which maintains the temperature of the substrate constant. A temperature sensor is also arrayed on the upper side of the substrate near the membrane.

Pressure measuring element

Very fine solder-coated conduction paths are made on ceramic, glass or enamel substrates by the combination of a first step in thick-film technology followed by the photo-masking and etching steps typical of thin-film technology, after which galvanic reinforcement of the initial calcined copper paste layer is performed in the locations where the initial layer is exposed by the developed mask. A lead-tin solder layer is then galvanically deposited, which is thicker than the mask, after which the mask is removed and the newly exposed portions of the initial copper layer are etched away. A reflow treatment of the solder layer pattern consolidates the solder layer by melting on top of the boundaries of the unetched initial copper layer. It is possible to obtain conduction path spacings down to 50 .mu.m with conduction paths coated with solder that have excellent adhesion to ceramic, glass or enamel substrates.

Process of producing galvanic layers of solder of precise contour on

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 obtained by applying either a metallic layer cover the membrane and utilizing the capacity of the metallic layer with respect to a counter electrode, or applying strain-compression sensitive resistors on the membrane. The membrane, after the electrodes or resistors are applied, is coated with a protective glass glaze (6). The pressure transducer is particularly for determining the pressure conditions in the induction pipe of an internal combustion engine.

Pressure sensor

Growing community of inventors

Weil der Stadt, Germany

Kurt Spitzenberger