Kistler Holding Ag

Kristal Instrumente Ag

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Reto Calderara

Christof Sonderegger

Hans-Conrad Sonderegger

Jochen Von Berg

Alfred Wenger

Jeffrey M Schnellinger

Ulrich Albicker

Peter Meister

A piezoresistive sensor chip element of a pressure sensor has lower face with an outer edge, an adhesion area and a non-adhesion area. The chip has a closed chip cavity for measuring the pressure of a medium flowing around the chip. The upper face of a substrate is fastened only at the adhesion area of the chip. The non-adhesion area extends at least over a circular area arranged centrally on the lower face and covers a third of the lower face's total area and extends over at least one connection area from the circular area to the edge of the lower face. The pressure in the pressure medium can spread through the connection area into a space under the non-adhesion area on the element lower face. The substrate has a recess located centrally under the sensor chip element.

Pressure sensor having a piezoresistive sensor chip element

A piezoresistive transduction element for incorporation into a pressure transducer includes a plate defining a diaphragm zone and preferably of silicon with piezoresistances diffused into it, an insulating plate of a glass material and a base plate. The plates are preferably connected to each other by anodic connections in a series of steps. The base plate is made of a material having substantially the same coefficient of thermal expansion as that of the material of the plate which defines the diaphragm zone. Furthermore, the dimensions of the base plate are matched to those of the diaphragm plate. By these measures the deformation forces exerted by the base plate and diaphragm plate on the insulating plate upon changes in temperature are of substantially the same magnitude and therefore there is minimum bending of the diaphragm plate. A symmetrical transduction element is created which has minimum zero point displacement and minimum sensitivity changes in use. Pressure transducers equipped with such piezoresistive transduction elements are therefore appropriate for high measuring accuracy, particularly in combination with an improved, elastically extensible securement of a holder which carries the transduction element within the transducer housing.

Pressure transducer utilizing a transduction element

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Seuzach, Switzerland

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