Pressure capacitive sensor is insensitive to temperature variations.

摘要

The present invention relates to a capacitive sensor of pressure of the type comprising a support plate 19, a fixed capacitor 7 mounted on the support plate 19 and a silicon wafer 13 willing on the support plate 19 so as to surround the fixed capacitor 7, the central part of the silicon wafer having been flattened in order to form a membrane 16, which plays the role of a plate of capacitor in the bottom of a cap 14 has a vacuum. / p & & p & the support plate is constituted of a silicon layer 21 and a layer of glass 20 fixed on the latter and mounted on the silicon plate 13, this layer of glass being appreciably thinner than the layer of silicon. Thus, in the plate stratified 20, 21 thus obtained, the difference of thermal expansion between the plate stratified 20, 21 of the silicon membrane 16 is considerably reduced because of the coefficients of elasticity and to the thermal expansion coefficients of the various layers 20 and 21.