Yu Qing, Zhang Kun, Cui Changcai, Zhou Ruilan, Cheng Fang, Ye Ruifang, Zhang Yi
Appl Opt. 2018 Nov 20;57(33):9722-9728. doi: 10.1364/AO.57.009722.
In this paper, a new method for measuring the thickness of transparent specimens using chromatic confocal microscopy (CCM) is presented. The conventional CCM thickness measurement model relies on capturing the focal points on the upper and lower surfaces of a transparent specimen. This model has strict specimen placement tolerance and a limited measurement range. In order to overcome these limitations, a new thickness measurement model was developed by adding an auxiliary reflector below the specimen. The thickness of the specimen can be determined by comparing the wavelengths of light focused on the auxiliary reflector before and after placing the measurement specimen. Theoretical analysis and simulation showed that the proposed method has twice the measurement range of the conventional model. In order to verify the proposed CCM measurement model, a laboratory thickness measurement system was developed by the authors' team. A commercial laser scanning confocal microscope (Carl Zeiss LSM780) was used as the reference system. A set of quartz glasses was measured using both the proposed system and the reference system. Experimental comparison showed that the proposed method was able to achieve a measurement accuracy of 0.25 μm. In addition, repeated measurements conducted at different heights showed negligible variation. Thus, it can be concluded that the specimen placement tolerance was improved significantly compared with the conventional model.
本文提出了一种利用彩色共聚焦显微镜（CCM）测量透明样品厚度的新方法。传统的CCM厚度测量模型依赖于捕获透明样品上下表面的焦点。该模型对样品放置的公差要求严格且测量范围有限。为了克服这些限制，通过在样品下方添加一个辅助反射镜开发了一种新的厚度测量模型。通过比较放置测量样品前后聚焦在辅助反射镜上的光的波长，可以确定样品的厚度。理论分析和模拟表明，该方法的测量范围是传统模型的两倍。为了验证所提出的CCM测量模型，作者团队开发了一个实验室厚度测量系统。使用商用激光扫描共聚焦显微镜（卡尔蔡司LSM780）作为参考系统。使用所提出的系统和参考系统对一组石英玻璃进行了测量。实验比较表明，该方法能够达到0.25μm的测量精度。此外，在不同高度进行的重复测量显示变化可忽略不计。因此，可以得出结论，与传统模型相比，样品放置公差得到了显著改善。
