碩士 / 國立臺灣海洋大學 / 電機工程學系 / 101 / The main objective of this paper is the research and improvement on ultrasonic array imaging system. Research is going to be focused on the sensor device of imaging system of the ultrasonic imaging system so as to reach the goal of enhancing the reflective wave signal intensity of the sensor device and improving the signal sensing distance.
The sensor devices prepared in this paper are respectively the ultrasonic sensor device made up of piezoelectric piece with resonant frequency of 600 KHz and micro-bridge structure ultrasonic sensor device using MEMS process technology. In the ultrasonic sensor device part, the sensor device is prepared respectively in the ways of in-parallel circuit, in-series circuit, or a combination of in-parallel and in-series circuit. In micro-bridge structure ultrasonic sensor device aspect, 32×1, 32×2, 32×4, 32×8, 32×16, 32×31 in-parallel piezo-electric layer PZT thin film micro-bridge structure ultrasonic sensor devices are formed respectively.
Among the ultrasonic sensor devices prepared in this paper, sensor device with 64 in-parallel devices is the optimal device for receiving reflective wave signal, which has resonant frequency of 6.73MHz, anti-resonant frequency of 41.07MHz; remanent polarization is 18.5 uC/cm2, coercive electric field is 3.63 V/cm. In the underwater test, the signal sensing distance is 16 meters, then after amplification of 60dB, the sensing signal intensity is 0.53V; at 600KHz, the detection sensitivity is -208.32 dBreV/uPa; in the sound field aspect, the sound field graph at low frequency is more directional, and the sensing signal right at -10°~+10°in front of the sensing target is better, and at 600KHz and high frequency, the sound field graph approximates a round shape, and there is no specific directionality, in the mean time, along with the increase of the test frequency, the sensed signal intensity is also better than that at low frequency.
Among the micro-bridge structure ultrasonic sensor devices prepared in this paper, 32X31 micro-bridge structure ultrasonic sensor device is the optimal device of reflective wave signal, which has resonant frequency of 4.39MHz, anti-resonant frequency of 25.79MHz; the remanent polarization is 7.02 uC/cm2, coercive electric field is 7.6 kV/cm.
In the underwater test, the detection sensitivity is -205.99 dBreV/uPa at 600KHz; in the sound field aspect, the sound field graphs of low frequency, high frequency and 600KHz approximate round shape, and there is no specific directionality; in the mean time, as the test frequency increases, the sensed signal intensity is also better than that at low frequency.
| Identifer | oai:union.ndltd.org:TW/101NTOU5442063 |
| Date | January 2013 |
| Creators | Te-En Hsu, 許得恩 |
| Contributors | Chung-Cheng Chang, Yeong-Chin Chen, 張忠誠, 陳永欽 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 92 |
Page generated in 0.0086 seconds