用于共聚焦显微镜物镜微调压电Z轴定位平台设计

Design of Fine Tuning Piezoelectric Z-axis Positioning Platform Used for Objective Lens of Confocal Microscope

针对共聚焦显微镜检测系统光学成像中物镜成像质量不稳定,要求定位精度高、安装空间小等问题,设计了一个基于倒圆角直梁型柔性铰链的压电Z轴物镜定位平台。采用带有应变片传感器的压电陶瓷作为动力驱动,单平行四杆机构为放大机构对压电陶瓷产生的位移进行高线性放大。通过计算出倒圆角直梁型柔性铰链的刚度,推导出物镜定位平台的输出位移以及系统容许设计最大刚度,利用ANSYS对物镜定位平台进行了静力学、模态分析验证。文中选用PZT压电陶瓷规格5 mm×5 mm×36 mm,利用压电控制器BP-303检测陶瓷实时位移以及提供0~150 V电压斜坡信号,物镜定位平台输出端位移由传感器测得,实际输出位移与理论计算结果、仿真分析结果分别相差2.02%、3.8%,定位台输出端最大输出位移为101.4μm,最小调节分辨率为0.33 nm,系统谐振频率为618.84 Hz,满足物镜的快速聚焦和定位需求。

A piezoelectric z-axis objective lens positioning platform based on fillet straight beam flexure hinge was designed to solve the problems of unstable imaging quality,high positioning accuracy and small mounting space in optical imaging of confocal microscope detection system.Piezoelectric ceramic with strain gauge sensor was used as power drive.The single parallel four-bar mechanism amplified the displacement generated by the piezoelectric ceramic for the amplifying mechanism with high linearity.By calculating the stiffness of the fillet straight beam type flexible hinge,the output displacement of the objective lens positioning platform and the maximum allowable design stiffness of the system were calculated,the static and modal analysis of the objective lens positioning platform were validated by ANSYS.In this paper,PZT piezoelectric ceramic specifications 5 mm×5 mm×36 mm was adopted,piezoelectric controller BP-303 was used to detect real-time ceramic displacement and provide 0~150 V voltage ramp signal,the displacement of the output of the objective lens positioning platform was measured by the sensor,the actual output displacement and theory.The actual output displacement differs from the theoretical calculation result and the simulation analysis result by 2.02% and 3.8% respectively.The maximum output displacement of the output of the positioning stage is 101.4 μm,the minimum adjustment resolution is 0.33 nm and the system resonant frequency is 618.84 Hz,which meets the fast focusing and positioning of the objective lens.