Thick-Layer Piezo-Resistive Pressure Sensor with Freestanding Diaphragm

Publication Number: SI22106A
Application Date: 18. 7. 2005
Assignee/Applicant: HYB d. o. o. [SI], Jožef Stefan Institute [SI]
Inventor: Darko Belavič, Marko Hrovat, Marko Pavlin, Marina Santo Zarnik
Title: Debeloplastni piezouporovni senzor tlaka s prosto stoječo membrano [SL], Thick-Layer Piezo-Resistive Pressure Sensor with Freestanding Diaphragm [EN]
Description: The present invention relates to a thick-layer piezo-resisitve pressure sensor with freestanding diaphragm, made in such a way that the diaphragm inside the enclosure is from one side supported by a supporting ring from hard material, which defines the diameter of the active surface of the diaphragm, and on the other side at the edge of the active surface it is supported by an elastic washer. The washer maintains the shape of a ring, which is of equal diameter than the supporting ring so that both rings together form a flexible fixing of the diaphragm, while upon exposure to pressure the deformation of the diaphragm due to the fixing can be neglected and small specific deformation of the diaphragm are most explicit in its central part. In the area of the largest diaphragm deformation there are on both sides of the diaphragm on each side two symmetrical thick-layer resistors featuring explicit piezo-resistive properties. Upon exposure to pressure these two resistors are expanded, while the two other ones are contracting, therefore the resistivity of the first pair is increasing and that of the second ones decreasing. All four resistors are via conductive links and terminal pads connected to a Wheatston bridge. With equal exposure to pressure such a construction features larger mechanical deformation levels than in cases when the diaphragm is attached to a support, which results in enhanced pressure sensitivity of the sensor.
Category: Nanotechnology and New Materials
Technology application codes: Electronics, IT and telecoms, Measurements and standards
Market application codes: Other electronics related, Industrial products
Patent offices: UIL RS