| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 91 === An excimer laser micro-machining technique was used to fabricate a micro pressure sensor, 0.7 mm in diameter, on a piezoelectric polyvinylidene fluoride (PVDF) film. The PVDF film is known for its large piezoelectric stress coefficient, high frequency response, and the capability to sustain large impact pressure. These properties make it a good candidate for dynamic measurement. Meanwhile, the excimer laser micro-machining technique is characterized by its high precision and high working energy density and is particularly fit in our fabrication purpose.
In order to increase the efficiency of the laser machining, a chrome plated optical mask was employed to fabricate the sensor. The sensor was then dynamically calibrated using a pencil breaking method and was applied to measure the impulse pressure associated with the collapse of a cavitation bubble near a solid boundary. It is demonstrated that the PVDF piezoelectric sensor is very suitable for measuring the impulse pressure of high amplitude and short duration.
To construct a complete system for multi-channel pressure measurement, we also carefully designed a signal processing circuit consisting of operational amplifiers connected to the sensor array. Signal from all the independent sensing units were then sampled simultaneously to a personal computer using fast-sampling A/D cards.
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