液体变焦透镜的响应时间特性分析

Analysis of response time characteristics on liquid variable-focus microlens

为了研究液体透镜响应时间特性,文中通过建立液体透镜系统无量纲参数理论模型,分析液体透镜器件的振荡衰减时间、液体密度、粘滞系数、表面张力系数、镜头内径5个基本参量之间的关系,表明在对数坐标下无量纲振荡衰减时间与无量纲镜头参数之间关系分别为斜率等于1和1/2的两条直线。理论结果与文献实验数据对比证明两条直线分别对应过阻尼和欠阻尼情况,交点对应临界阻尼状态。根据临界阻尼状态具有界面稳定的最小响应时间特点,提出了满足临界阻尼条件的液体变焦透镜的设计新方法,给出了不同镜头内径和液体界面张力下透镜的最佳参数组合。

To solve the problem of the response time characteristics of the liquid lens, a dimensionless parameter theoretical model with dimensionless parameters is built. Using the dimensional analysis, the relationship of the 5 basic parameters, such as response time, liquid density, coefficient of viscosity, surface tension coefficient, and the inner diameter of the lens is analyzed. On a logarithmic scale, the relationships of the dimensionless damping time and the dimensionless lens parameter are two straight lines with slopes as 1 or 1/2. The comparison of theoretical results with experimental data shows that, the two lines are respectively corresponding to under-damped meniscus and over-damped meniscus lens, and the intersection point is corresponding to the critical damping state. According to the characteristics of critical damping oscillation state with minimum response time, the liquid lens design method for meeting the critical damped conditions is presented and the best parameter combination of different inner diameters and interfacial tension is given.