Opt Lett. 2019 Nov 1;44(21):5258-5261. doi: 10.1364/OL.44.005258.
An absolute optical encoder with nanometric positioning repeatability is introduced and investigated. The encoder consists of an improved scale grating and a compact two-probe reading head. The scale grating contains multiple unevenly spaced distance marks that are superimposed onto grating grooves. The two probes, which are located in the sensor head, read the marks and the grating grooves to determine the position and displacement simultaneously. For one of the two probes, a mask with the same code design with the marks on the scale grating generates a pulse signal to locate the position of the marks approximately-with an accuracy of less than about half a grating period (0.5 μm). For the other probe, light beams are configured for grating interferometry to measure displacement with nanometer-scale resolution. In this Letter, high-quality sinusoidal signals of grating interferometry are used to accurately locate the marks on the scale grating, with stable 100-subdivision phase information. The testing results show that the positioning repeatability can reach 10 nm for a motion range of several tens of millimeters.
本文介绍并研究了一种具有纳米级定位重复性的绝对式光学编码器。该编码器由改进的标尺光栅和紧凑的双探头读取头组成。标尺光栅包含多个不均匀间隔的距离标记，这些标记叠加在光栅槽上。两个探头位于传感器头中，读取标记和光栅槽，以同时确定位置和位移。对于两个探头中的一个，具有与标尺光栅上的标记相同编码设计的掩模会生成脉冲信号，以便大致确定标记的位置，精度小于半个光栅周期（0.5μm）。对于另一个探头，光束配置用于光栅干涉测量，以纳米级分辨率测量位移。在本信中，使用高质量的光栅干涉正弦信号准确地定位标尺光栅上的标记，并具有稳定的 100 细分相位信息。测试结果表明，在几十毫米的运动范围内，定位重复性可达到 10nm。
