Pressure transducer utilizing a transduction element
First Claim
1. A transduction element comprising a diaphram plate defining at least one diaphragm zone and made of semiconductor material having at least one piezoresistance, an insulating plate to which said diaphragm plate is secured, and a base plate secured to the surface of the insulating plate remote from the diaphragm plate, the material and dimensions of said base plate being balanced in relation to the diaphragm plate so that with temperature changes the deformation forces exerted by the diaphragm plate and the base plate on the insulating plate are substantially equal, said materials of the base plate and diaphragm plate having substantially equal coefficients of thermal expansion, whereby the transduction element has a symmetrical stress status.
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Accused Products
Abstract
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.
38 Citations
17 Claims
- 1. A transduction element comprising a diaphram plate defining at least one diaphragm zone and made of semiconductor material having at least one piezoresistance, an insulating plate to which said diaphragm plate is secured, and a base plate secured to the surface of the insulating plate remote from the diaphragm plate, the material and dimensions of said base plate being balanced in relation to the diaphragm plate so that with temperature changes the deformation forces exerted by the diaphragm plate and the base plate on the insulating plate are substantially equal, said materials of the base plate and diaphragm plate having substantially equal coefficients of thermal expansion, whereby the transduction element has a symmetrical stress status.
- 12. A pressure transducer incorporating a transduction element, comprising a plate defining at least one diaphragm zone and made of semiconductor material having at least one piezoresistance, an insulating plate to which the diaphragm plate is secured, and a base plate secured to the surface of the insulating plate remote from the diaphragm plate, the material and dimensions of said base plate being balanced in relation to the diaphragm plate so that with temperature changes the deformation forces exerted by the diaphragm plate and the base plate on the insulating plate are substantially equal, whereby the transduction element has a symmetrical stress status, said transduction element being secured directly, or by means of an intermediate support secured to the base plate, onto a holder arranged in the transducer housing.
Specification