Piezoelectric Pressure Sensors Based On Flexible PZT Thick-Film Composite Device

摘要

In this thesis, piezoelectric diaphragm pressure sensors have been proposed and developed. The piezoelectric Lead Zirconate Titanate (PZT) thick film was used in this sensor as sensing element due to its good piezoelectric property and mechanical flexibility. This kind of PZT thick film was fabricated recently using a tape-casting processing. By this process the PZT film thickness can be controlled in the range from tens to hundreds microns, making the novel flexible PZT diaphragm sensor realizable. Two structures of pressure sensor were designed and fabricated, and the relationship between generated voltage signals to applied pressures of the electromechanical model has been analyzed theoretically. For sandwiched structure sensor, the properties of the sensor to measure low frequency fluctuating pressures have been investigated experimentally. A test setup was designed and applied to generate pulsing fluid pressure waves and calibrate the sensitivities of sensor samples. The proposed pressure sensor exhibited highly sensitive response to low frequency dynamic pressure loading. The effectiveness of this sensor in human arterial pulse monitoring was studied and reported. For pressure sensor with unimorph structure, a blast wave pressure test was conducted using shock tube setup to study its sensing ability to intensive, transient pressure loading. Different sized sensors were tested and showed almost linear relationship to blast pressure in the given range.