碩士 / 國立臺灣海洋大學 / 電機工程學系 / 106 / This paper uses semiconductor process technology to fabricate ultrasonic sensing components for underwater environments. It mainly uses the electro-mechanical conversion characteristics of piezoelectric material lead zirconate titanate Pb(〖Zr〗_0.52 〖Ti〗_0.48) O_3to transmit and receive ultrasonic waves under the water surface. The main structure of the self-made component includes a lower electrode, a buffer layer, a piezoelectric layer, an upper electrode, and a waterproof layer, and the intensity of the transmitted signal is changed by adjusting the surface area of the piezoelectric layer of the element and improve the receiving intensity of sound waves by changing the number of component arrays, adjusting the film thickness of the piezoelectric layer, and improving the component yield.
The ultrasonic emission component produced in this paper consists of 1 by 64 single elements. An array of elements in the component is connected in parallel to analyze the surface area of the piezoelectric layer of the transmitting element. Comparing the total surface area of the piezoelectric layer of the emitting end element is 64 mm^2and 48 mm^2. The ultrasonic receiving component compares the array number to include 2880 (48*60) elements and 3360 (48*70) elements to form a parallel array. After the ultrasonic wave receiving component is completed, the underwater component is measured in water, received signal intensity measurement, sound field measurement, component sensitivity measurement, etc. The electrical measurement part includes the measurement of the resonance and anti-resonance frequency, the dielectric constant quantity measurement, the measurement of the isoelectric circuit, the electromechanical coupling coefficient measurement and the hysteresis curve measurement, etc.
In this paper, the thickness of the lead zirconate titanate film and the number of component arrays of the ultrasonic receiving component are changed to analyze the characteristics of the ultrasonic receiving array. As the thickness of the piezoelectric layer PZT film of the receiving end element increases to 2000 nm, a higher dielectric value and component sensitivity can be obtained, and the intensity of the transmitted and received signals is emitted by the self-made emitting element and received by the self-made sensing element. The strongest signal strength of 1.2V can be received in the 10MHz band.
According to the analysis of the number of component arrays, the resonant frequency of the array number 2880 is 64.97 MHz. When the number of arrays is increased to 3360, the resonant frequency of the measuring component is 48.636MHz. As the number of arrays increases, the resonance and anti-resonance frequencies of the components decrease, but the effect of changing the number of component arrays on the dielectric value is not significant.
| Identifer | oai:union.ndltd.org:TW/106NTOU5442030 |
| Date | January 2018 |
| Creators | Chiu, Yu-Shiang, 邱昱翔 |
| Contributors | Chang, Chung-Cheng, 張忠誠 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 69 |
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