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摘要: 超精密位移测量技术不仅是精密机械加工的基础,在以摩尔定律飞速发展的芯片制造行业中也起到决定性的作用。以光栅栅距为测量基准的光栅位移测量系统被广泛应用于多维测量系统,光栅位移测量系统与激光位移测量系统相比,大大降低了对使用环境的湿度、温度和气压的要求。本文主要介绍了近年来国内外基于二维光栅的位移传感系统光学结构的发展现状,从零差式和外差式光栅干涉测量原理入手,综述了基于单块二维光栅的光学结构到多块二维光栅耦合设计的光学结构发展历程,对比分析了几种二维光栅位移测量系统的优缺点,并展望了二维光栅位移测量系统发展趋势,总结了二维光栅位移测量系统的工程化进程。Abstract: Ultra-precision displacement measurement technology is not only the basis of precision machining, but also plays a decisive role in the chip manufacturing industry that is rapidly developing in Moore's Law. The grating displacement measurement system based on the grating pitch is widely used in multidimensional measurement system. Compared with the laser displacement measurement system, grating displacement measurement system greatly reduces the environmental requirements for humidity, temperature and pressure. In this paper, the development status of the optical structure of displacement sensing system based on two-dimensional grating in recent years is introduced. The principles of zero-difference and heterodyne grating interferometrys are introduced. The optical structure based on single-block two-dimensional grating is reviewed. The development history of the optical structure in single-block two-dimensional grating to coupling designs of multi-block two-dimensional gratings is summarized, the advantages and disadvantages of several two-dimensional grating displacement measurement systems are compared and analyzed, and the development trend of two-dimensional grating displacement measurement system is prospected. The engineering process of two-dimensional grating displacement measurement system is summarized.
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表 1 基于二维光栅位移测量系统性能对比表
Table 1. Performance comparison of two-dimensional grating displacement measurement system
光栅分类 研究单位/公司/
研究者X与Y向分辨率/nm 光学传感器尺寸/
测量范围系统稳定性 特点 单二维光栅 华中科技大学王选择等学者 − 50 mm×50 mm − 同时进行X和Y向测量,在空间位置上实现同向测量。 国防科技大学林存宝等学者 分辨率优于0.125 nm;往返10 μm内,X向和Y向达2.35 nm和3.24 nm。 X向与Y向测量幅度可达:9.981 μm和9.978 μm。 在10分钟内的系统稳定性分别优于4 nm和6 nm。 同时实现高对比度和高信噪比;可获得八倍光学细分,未考虑因偏振分离性能引起的周期非线性误差的影响。 哈尔滨工业大学谭久彬等学者 分辨率优于0.122 nm。 125 mm×125 mm:可对X和Y方向上30 μm的位移进行测量。 机械振动引起的实时测量误差不超过0.15 μm,且测量重复性优于±57 nm。 成本低,可实现两次衍射;可消除周期非线性误差;增强测头的角度容差,不过信噪比较低,受振动影响较大。 双二维光栅 日本Gao.W等学者 X轴与Y轴分辨率均在1 nm以上。 光学传感器尺寸约为50 mm (X)×50 mm (Y)×30 mm (Z)。 X、Y和Z方向上的峰谷振幅误差分别为±10 nm、±10 nm和±3 nm。 系统原理简单,分别可实现三维位移测量和三维角度测量,受自准直单元尺寸限制,未考虑非线性误差分量的影响。 日本Li.X等学者 可分辨ΔX、ΔY、ΔZ方向上的2 nm步进运动;θX、θY方向上的0.1角秒步进运动;θZ方向上0.3角秒步进运动。 传感器头的尺寸为95 mm(X) ×90 mm(Y) ×25 mm(Z)。 X、Y和Z方向上,偏振间误差的峰谷振幅分别为±6 nm、±7 nm和±6 nm。 测量范围大,可实现六维测量,且对远程测量系统稳定性不佳。 多二维光栅 中国台湾国立中央大学Hsieh等学者 两轴分辨率优于3 nm,实现六维测量,位移和角度测量分辨率分别为2 nm和0.05 μrad。 闭环配置驱动压电平台,可实现X,Y和Z方向上1 μm的移动距离。 在1小时内分辨率稳定性可达14 nm。 同时实现六维测量和长行程测量,测量精度高,且结构复杂,稳定性较差,测量范围小。 哈尔滨工业大学林杰、陆振刚等学者 X向和Y向实现光学2细分,不进行电学细分下,检测分辨力为$2\sqrt 2 $ μm。 两方向运动范围均为100 μm,Z向的运动范围为20 mm。 稳定性较好 杂散光影响小 -
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