基于数字微镜器件的并行彩色共聚焦测量系统

Parallel chromatic confocal measurement system based on digital micromirror device

彩色共聚焦技术因其高分辨率、高测速的特点,在表面形貌测量领域备受关注,然而现有的彩色共聚焦技术多为单点测量,一定程度上限制了测量效率。本文在彩色共聚焦技术的基础上,以DMD作为光分束器件,结合自主研发的大口径色散管镜,利用面阵彩色相机作为光电接收器件,研究和建立了基于数字微镜器件的并行彩色共聚焦实验平台,实现了对被测物面上多个探测点的并行图像处理。最终,利用所搭建的并行彩色共聚焦测量系统,对50μm高的台阶和自制台阶进行了测量,并对硬币的表面形貌进行了三维恢复。实验结果表明,该测量系统的轴向测量范围为300μm,测量精度达到微米级;同时,能够较好地恢复硬币的表面形貌特征,具有较好的测量效率与可靠性。

The chromatic confocal technique has garnered much attention in the field of surface topography measurement due to its high accuracy,resolution,and rapidity of operation.However,the existing chromatic confocal methods are mostly based on single-point measurement,which restricts their measuring efficiencies.To address this shortcoming,parallel chromatic confocal measurement system based on the chromatic confocal technique was proposed and studied in this paper.In this experimental system,DMD was used as an optical beam splitter,a self-developed dispersive tube lens was applied to produce axial dispersion,and a color camera was used as a photoelectric receiving device.A self-developed color conversion algorithm was also used to simultaneously obtain spectral information from multi-confocal-points.Finally,a parallel chromatic confocal measurement experimental platform was constructed,the experimental measurements corresponding to 50μm high steps and self-made steps were performed,and the surface topography restoration experiments were conducted.The experimental results indicate that the axial measuring range of the system is 300μm,and the measuring accuracy is able to achieve micron level.Further,as a 3D measurement system,the proposed technique was verified to be capable of reconstructing the surface topography of a coin based on one-shot.