考虑封装结构的AT切石英晶体谐振器的有限元分析

发布时间：2018-07-15 08:35

【摘要】：随着工业智能化水平的不断发展,在线监测系统对石英晶体谐振器的性能要求变得越来越高,主要表现在器件的准确性、精密性、稳定性等方面。已有的石英晶体谐振器的研究,大多数是根据Mindlin板或Lee板理论,计算晶体板共振的频率和主要的性能参数,同时可以得到简化问题的解析解。但对于频率较高的基频、三次泛音、五次泛音等高阶泛音谐振器,得出这些精确的解析解是很困难的。石英晶体谐振器是典型的动态结构组件,目前对它的研究主要是在准静态条件和直行波假设下进行的,一般合理地忽略了宽度方向的振动模态。但是,这样的设计方法容易引起宽度方向的寄生模态的忽略,难以满足实际的工程产品设计需求。在设计产品时,设计者一般需要结合实验数据的经验等,利用有限元软件进行计算。本文应用一阶Mindlin板理论,分析了矩形石英晶体板的振动,得到了包含厚度剪切模态、弯曲模态和面切变模态的振动解。为了研究寄生模态对石英板振动的影响,我们应用COMSOL软件,在耦合三个模态和五个模态的条件下,得到了板的振动频率和沿板的长度和宽度方向的中线处的位移。通过编写脚本文件,应用MATLAB和COMSOL软件进行联合仿真,考虑了不同电极质量比等参数,得到了长厚比和宽厚比的频谱关系图,这些结果与已有文献的结果一致。本文还研究了石英晶体谐振器的不同的封装结构因素,如电极尺寸、导电胶直径、导电胶位置、封装上盖等对石英晶体谐振器共振频率和厚度切变模态的影响。石英晶体板的分析基于Mindlin板理论,加上谐振器的完整结构模型,可以详细分析上述变量因素对振动位移和器件特性的影响程度,而这些分析结果为石英晶体谐振器的参数优化设计提供了重要参考。
[Abstract]:With the development of industrial intelligence, the performance requirements of quartz crystal resonator are becoming higher and higher in the on-line monitoring system, which is mainly reflected in the accuracy, precision and stability of the device. Most of the existing researches on quartz crystal resonators are based on the Mindlin plate or Lee plate theory to calculate the resonance frequency and main performance parameters of the crystal plate. At the same time the analytical solution of the simplified problem can be obtained. But for high-order overtone resonators such as base frequency, cubic overtone and quintic overtone, it is very difficult to obtain these exact analytical solutions. Quartz crystal resonator is a typical dynamic structure component. At present, the research of quartz crystal resonator is mainly carried out under the quasi-static condition and the assumption of straight traveling wave, and the vibration mode in width direction is generally and reasonably ignored. However, this design method is easy to cause the parasitic modes in width direction to be ignored, so it is difficult to meet the actual design requirements of engineering products. When designing products, designers generally need to combine the experience of experimental data and use finite element software to calculate. In this paper, the vibration of rectangular quartz crystal plate is analyzed by using the first order Mindlin plate theory, and the vibration solutions including thickness shear mode, bending mode and plane shear mode are obtained. In order to study the effect of parasitic modes on the vibration of quartz plate, we use COMSOL software, under the condition of coupling three modes and five modes, we obtain the vibration frequency of the plate and the displacement along the midline along the direction of the length and width of the plate. By writing the script file, using MATLAB and COMSOL software to carry on the joint simulation, considering the different electrode mass ratio and other parameters, the spectrum relation diagram of the ratio of length to thickness and the ratio of width to thickness is obtained. These results are consistent with the results of the previous literature. The effects of different packaging structure factors such as electrode size, conductive adhesive diameter, conductive adhesive position and package cover on the resonant frequency and thickness shear mode of quartz crystal resonator are also studied in this paper. The analysis of quartz crystal plate is based on Mindlin plate theory and the complete structure model of the resonator can be used to analyze the influence of the above variables on the vibration displacement and device characteristics in detail. These results provide an important reference for the optimization design of quartz crystal resonator.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN752.2

【参考文献】