Patent Number: 6,252,759

Title: Capacitive pressure sensors or capacitive differential pressure sensors

Abstract: In order to avoid short-circuits between the electrodes, the pressure sensor comprises: a substrate (11) made of ceramic material, on one surface of which an electrode (13) and a glass layer (14) formed from an original glass frit are disposed; a diaphragm (12) made of ceramic material, which is permanently joined and pressure-sealed to the substrate by means of the original glass frit acting as a spacer (17) holding the diaphragm and the substrate from each other to form a cavity (16), and which on the cavity side is provided with an electrode (15); and leads (18, 19) which extend inwards and/or through the diaphragm (12) to the electrodes (13, 15) in the region of the spacer (17). The differential pressure sensor is formed in a mirror-inverted arrangement in relation to the centre plane of the substrate, so that it carries two pressure sensors. These are pressure-linked by a hole (41) filled with oil and connecting the two cavities and leading through the substrate and outwards. In a further development, thin insulating layers (20; 40, 40') made of the material of the ceramic of the substrate or of a high-temperature glass can be fixed on the glass layer(s), respectively.

Inventors: Lange; Jurgen (Vellmar, DE), Gill; Norbert (Vellmar, DE)

Assignee: Endress + Hauser GmbH + Co.

International Classification: G01L 9/00 (20060101); H01G 007/00 ()

Expiration Date: 06/26/2018