基于并行共聚焦显微系统的物方差动轴向测量

差动共聚焦显微成像技术可以获得很高的轴向测量精度,然而已有的差动共聚焦测量技术主要适用于激光扫描共聚焦,还不能满足微纳加工过程中对工件进行非接触式的在线、在位测量的要求。本文在分析差动共聚焦显微成像系统能够实现轴向测量原理的基础上,提出了适用于并行共聚焦技术的轴向测量方法。该方法利用均匀白光照明,在像方只需要使用一台相机做探测器,在物方通过移动载物台分别对样品在焦前和焦后两次成像,根据预先刻度好的差动曲线就可以得出物体表面的高度。理论模拟与实验结果均表明,该方法可以实现高精度的轴向测量,对500nm的台阶样品测量的平均误差为2.9nm,相对误差为0.58%。该方法简单、廉价、测量精度高,可以用于普通显微镜,易于实现样品的三维快速形貌还原与测量。

Object-side based differential axial measurementbased on parallel confocal microscopy

The differential confocal microscopic imaging technology can obtain high axial measurement accuracy.However,existing differential confocal microscopic imaging techniques mainly employed to laser scanning confocal microscopy can not satisfy requirements of non-contact online and on-site measurement for workpieces during micro-nano machining processes.Axial measurement methods that were applicable to parallel confocal technology were proposed based on the analysis that differential confocal microscopic imaging system could realize axial measurement principle.In the method,a uniform white light illumination was used.The image space only needed a camera as detector,and the object space made twice imaging of samples before and after the focal point by moving the objective table,then the height of the object surface could be obtained according to the scaled differential curve in advance.Both the theoretical simulation and experimental results are indicated that the method can realize axial measurement with high accuracy.For the measurement of step samples with 500 nm,the average error is 2.9 nm and the relative error is 0.58%.The method is simple and low-cost with high measurement accuracy,thus can be used for general microscope and be easy to realize rapid restoration and measurement of three-dimensional images for samples.