压电谐振式微质量测量系统

基于压电晶体的正、逆压电效应,对压电谐振器的构成原理及压电晶片谐振频率的质量敏感原理(Sauerbrey方程)进行了分析。基于Sauerbrey测量原理,设计了压电谐振式微质量测量系统,对该系统的设计方案进行了分析。为减小温度等环境因素对压电晶体检测性能的影响,系统采用两个相同的石英晶体振荡电路构成双谐振式的压电晶体振荡器。采用模块化设计思想,对该测量系统各模块进行了设计与实现,并对系统性能进行了测试。结果表明,当测量端加载的质量越大,系统测量出的谐振差频值则越大,实验结果与理论分析结果吻合较好。相对于线性的理论结果,该实验结果的非线性误差为5.5%。该系统实现了压电谐振频率的变化与被测微质量之间的变换,能够实现对微质量进行测量。

Micro mass Measurement System Based on Piezoelectric Resonance

Based on direct and converse piezoelectric effects of piezoelectric crystal, the construction principle of piezoelectric resonator and the mass sensitivity principle of piezoelectric wafer resonant frequency (Sauerbrey equation) are analyzed in this paper. According to the Sauerbrey equation,a micro mass measurement system based on piezoelectric resonance is designed,and its design scheme is analyzed.To reduce the influence of environmental factors on the piezoelectric crystal detection,the system consists of a dual resonant piezoelectric crystal oscillator which uses two same quartz oscillation circuits.By the method of modular design, each of modules in the system is designed and implemented, and the performance of the system is tested.The results show that when the loading quality at the measuring end increases,the resonance frequency difference measured by the system is greater,and the experimental results are consistent with the theoretical analysis results.Compared with the linear theoretical results,the nonlinear error of experimental results is 5.5%.The system implements the transformation between the change of the piezoelectric resonant frequency and the measured micro mass, and can achieve the micro mass measurement.