B3.4 - Amplitude Response of an Overload-Resistant Pressure Sensor
- SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
- Proceedings SENSOR 2011
- B3 - Mechanical Sensors I
- T. Kober, R. Werthschützky - Technische Universität Darmstadt (Germany)
- 267 - 270
Differential pressure sensors with silicon diaphragms provide a nominal measuring range of 10 mbar. An additional external overload protection mechanism is required to achieve an overload reserve up to 160 bar.
To integrate the overload protection at the wafer level, a micromechanical overload protection is needed. Such a micromechanical overload protection for differential pressure sensors can be produced from heat-treated glass.
Here, we demonstrate an overload capability reaching 50 bar for a silicon diaphragm with a nominal measuring range of 10 mbar and a diaphragm thickness of 30 μm. With theoretical network analysis and applied load tests, reliable and robust overload protected pressure sensors are available. Depending on the capillary diameter, the dynamic overload capability corresponds to the frequency response of the silicon diaphragm and the acoustic system. This correlation will be investigated with dynamic pressure calibration. The preferred dynamic pressure source consists of a network analyser and a piezoelectric stack actuator, which is driven by a high voltage amplifier up to 1000 V. The amplitude response of the diaphragm deflection has a low pass characteristic. The influence of the diaphragm offset deflection and the capillary tube diameter will be discussed.