【作者】 刘娟；

【导师】 宋光德；

【作者基本信息】 天津大学 ， 精密仪器及机械， 2006， 硕士

【摘要】 在超声领域,压电超声传感器是应用较为广泛的一种声电转换元件。但由于传统的压电传感器存在着空气与普通的压电材料之间严重不耦合现象,所以压电传感器并不是高效率的超声源。当然,为了提高效率可以在空气与压电材料间增加耦合层,但这样又会降低传感器带宽。现在,随着MEMS技术的发展,一种全新的超声传感器已经出现,它就是电容式微加工超声传感器(cMUT)。由于其采用了表面微加工等微加工工艺,很好地克服了压电传感器的许多缺点,且具有易于制造、尺寸小、自身噪声低、工作温度范围大以及易于实现电子集成等众多优点,大有取代压电传感器之势。正是基于以上的这种情况,才提出了本课题的研究。本文根据国外相关的研究经验,设计了一种切实可行的cMUT结构和工艺流程,并对其进行了仿真分析,最后给出了测试系统的总体设计。本文主要完成的工作1.查阅相关文献,了解国内外对cMUT研究的最新动态。主要了解cMUT的基本结构、工作原理、激励方式、结构与性能的关系以及加工方法和工艺流程,并了解对cMUT的建模和仿真方法。2.设计出可用于测试的cMUT结构,并采用表面微加工工艺,设计出适合于结构的加工工艺流程。3.利用有限元分析软件ANSYS对结构进行3D建模和静态、模态的仿真分析,得到结构的固有共振频率和振动图形。4.用ANSYS软件里的耦合场分析模块及参数化设计语言(APDL)进行编程,对结构进行力电耦合模态和谐波仿真,并根据仿真的结果最终确定结构方案。5.对用于cMUT的性能测试的系统进行总体设计。更多还原

【Abstract】 Piezoelectric ultrasonic transducer is sound-electronic converor, which is commonly used in the field of ultrasonic. But the large impedance mismatch of air and ordinary piezoelectric material implies that traditional piezoelectric ultrasonic transducer is inherently an inefficient ultrasonic source. Certainly, in order to improve efficiency, a matching layer is usually placed in between the piezoelectric and air. But the bandwidth is reduced at the same time. As the development of MEMS technology , a new kind of ultrasonic transducer, capacitive micromachined ultrasonic transducers, is designed. cMUT is made using surface micromachining techniques, so the shortcomings of traditional PZT are overcame. What’s more, cMUT is an alternative to the PZT because of being easy prone of manufacture, small dimension, low noise, wide operating temperature range and being easy to integrate with electronics.Based on the description above, the study on cMUT is presented. According to the oversea research information, a practical cMUT structure and its flow of manufacture techniques are designed, then simulated and imitated. Finally, the test system of cMUT’s performance is presented.The following are main achievements of this thesis:1. Study the national and foreign reference and conclude the latest development cMUT. Main concern is basic structure, the operation principle , the excitation methods, the influence on performance by structure parameters, the manufacture techniques and the methods of modeling and simulation.2. Present a kind of cMUT structure, which can be used on test, and its corresponding method of manufacture based on the surface micromachining techniques.3. Create the 3-D model of the structure and simulate with static and modal analysis using finite element analysis software ANSYS. The resonant frequency and the vibration graphs are obtained.4. Using coupling domain of ANSYS and parameter design language (APDL), the structure is simulated by the way of force-electric coupling modal and harmic analysis. Then the structure is confirmed according to the analysis results.5. Present the designing of the system for testing cMUT’s performance.更多还原