基于声表面波传感技术的微液滴检测方法

A Measuring Method of Microdroplet Detection Using Surface Acoustic Wave

为了提高声表面波(SAW)技术用于微液滴体积测量的精度,提出了一种差分面积拟合法.根据声表面波信号的特点分析了差分面积拟合法的合理性,在自行研制的声表面波液滴体积检测系统上对该方法的应用进行了验证.采用两种黏性不同的微液滴,分别为5～9μL的微水滴和微油滴进行了测量.对测得的信号分别采用曲线峰值法和差分面积拟合法与微液滴大小进行回归.实验结果表明,采用差分面积拟合法进行回归得到的模型的相关系数相比采用峰值法提高了4%以上,同时对两种微液滴的预测均方根误差(RMSEP)减小了37%以上,从而证明了该方法的有效性.

A differential-area method was proposed to improve the accuracy of measuring the volume of microdroplets based on a surface acoustic wave（SAW） technique.Firstly,the reasonableness of the differential-area method was analyzed based on the characteristics of SAW signal.Then,the method was validated using a developed liquid droplet volume detection system based on a SAW technique.Two kinds of liquid droplets with different viscosities,5—9 μL micro water droplets and micro oil droplets,were measured.The methods of curve peak and differential-area were applied respectively to build the regression relationship between the SAW signal and the size of microdroplets.With the differential-area method,the squares of correlation coefficients for the two kinds of liquid droplets were improved by 4%.Moreover,the root mean square errors of prediction（RMSEP） were reduced by over 37%.The experimental results show that the proposed differential-area method is efficient in detecting the volume of microdroplet by using SAW technique.