In this paper, a laser triangulation sensor (LTS) with improved measurement accuracy via integrating a diffraction grating was proved. Compared to conventional LTS that only has the information of one light spot, the diffraction grating generates several diffraction light spots on CMOS image sensor. This enables to obtain multiple results of the object displacement simultaneously during one sampling period. Thus, it is achievable to obtain a higher measurement accuracy by averaging operation, due to the averaging-error effect. The operating principle of the proposed method is explained in detail, and a prototype LTS is developed. Contrastive experiments are performed to evaluate the nonlinearity and repeatability of the developed LTS, which are generally combined to present the measurement accuracy of LTS. In the full-scale measurement range of 20 mm (F.S. = 20 mm), the results show that the measurement nonlinearity and repeatability of the developed LTS with diffraction grating are 0.113% of F.S. and 0.89 μm respectively, which are significantly improved compared to that without diffraction grating.

本文证明了通过集成衍射光栅可以提高测量精度的激光三角测量传感器（LTS）。与仅具有一个光点信息的常规LTS相比，衍射光栅在CMOS图像传感器上产生多个衍射光点。这使得能够在一个采样周期内同时获得物体位移的多个结果。因此，由于平均误差效应，可以通过平均操作获得更高的测量精度。详细说明了该方法的工作原理，并开发了原型LTS。进行对比实验以评估已开发LTS的非线性和可重复性，通常将它们组合起来以提供LTS的测量精度。