光栅尺关键技术研究
文献类型：学位论文
| 作者 | 卢炎聪 |
| 文献子类 | 博士 |
| 导师 | 周常河 |
| 关键词 | 光栅干涉仪 grating interferometer 标尺光栅 grating scale 光学细分 optical subdivision 信号探测 signal acquisition 位移测量 displacement measurement |
| 其他题名 | Research on Key Technologies of Grating Ruler |
| 英文摘要 | 光栅尺作为微纳米精密位移测量的重要工具，不仅具有亚微米级的分辨率和精度，而且能够进行数百毫米甚至米级的长程测量，相对于位移激光干涉仪，具有抗干扰能力强、成本低等优点，广泛应用于精密机床加工、机器人技术、半导体制造等领域。同时，工业制造在一定程度上标志着一个国家的发展水平，精密制造的飞速发展对测量精度和分辨率提出了新的要求，光栅尺作为制造的眼睛受到了许多研究人员的关注，广大学者提出了各种新型光学结构、信号解调方法等以提升光栅尺的性能。 本博士论文主要是针对光栅尺的关键技术进行深入的研究，分别对光栅尺的五个基本组成部分进行分析，包括光源、标尺光栅、光学结构、探测结构和探测器、信号处理技术，具体内容包括： 1、标尺光栅的设计制作和检测 标尺光栅是光栅干涉仪的核心部件，其质量和尺寸直接决定了系统的精度和量程。首先介绍设计标尺光栅的基础理论，包括标量衍射理论和矢量衍射理论。由于本研究的光栅尺结构要求标尺光栅在入射角度偏离利特罗角度入射时依然保持着高衍射效率，根据矢量衍射理论对1780线的标尺光栅进行优化，得到了符合要求的光栅结构。在光栅制作之后，还需对其进行检测。传统的光学衍射法和扫描显微镜技术已能够对小周期的标尺光栅进行评估，但在推广到大周期的标尺光栅时则存在耗时、成本高等缺点。为此，我们提出了一套测量系统，该系统结合显微物镜和CCD图像采集的特点，采取相关处理方法，得到亚像素级的测量重复精度，这不仅能够对大周期标尺光栅的均匀性进行评估，而且能得到高精度的结果，为计量光栅的评估奠定了基础。 2、基于对称利特罗装置的二自由度光栅干涉仪 光栅干涉仪是一种能够进行纳米级测量的光栅尺。光学结构是光栅干涉仪的重要组成部分，其决定了光栅干涉仪的分辨率和稳定性。我们提出了一种基于利特罗角度入射的二自由度光栅干涉仪结构，充分利用了双频激光光源和利特罗角度入射的特点，使得测量光束和参考光束不共径的区域减到最小以增强结构的抗干扰能力。同时，由于该结构分别对两个测量光束得到的信号分开处理，巧妙地解调出标尺光栅在水平方向和竖直方向上的位移。在传统的光栅干涉仪结构中，一维的标尺光栅只能进行一维的测量，要进行二维的测量只有采用二维的标尺光栅，此结构在增强系统稳定性的同时，打破了这个传统，基于一维的标尺光栅，能够同时得到二自由度的位移信息。 3、高光学细分的光栅干涉仪结构 分辨率是计量系统的一个重要指标，光栅干涉仪作为微纳米精密测量的一个重要工具，分辨率至关重要。光栅干涉仪的分辨率主要取决于光栅周期、电子细分倍数和光学细分倍数。对于确定的标尺光栅，光栅周期是确定，而电子细分倍数是由信号处理技术决定的。我们设计了多种光栅干涉仪的结构，大大地提升了光栅干涉仪的光学细分倍数。并对基于特殊棱镜的高光学细分光栅干涉仪进行了详细的设计分析和制作，通过高光学细分光栅干涉仪的测量结果与商用位移激光干涉仪的测量结果进行对比，从实验上验证了理论设计的可行性。另外，值得注意的是，本实验中设计的特殊棱镜实现的是8倍光学细分，这些高光学细分模块可以设计成更高的光学细分倍数，如12倍、24倍，甚至36倍等，高光学细分倍数仅仅受限于标尺光栅的尺寸和衍射效率。如此高的光学细分倍数，将大幅度地提高光栅干涉仪的分辨率，有利于提高光栅干涉仪的性能，拓展其在各领域中应用。 4、信号探测结构及信号处理技术 信号探测结构为信号处理提供了保证，我们总结了信号探测的若干个结构，分析了每个结构运行的机理，为探测结构的设计和改进奠定了基础。最后，为了解调位移信号，我们介绍了实验中使用的椭圆拟合方法，以降低解调误差。; Grating ruler plays an important role in industrial field such as high precision manufacture, robot technique and semi-conductor fabrication, as it not only provides high resolution up to nanometers with large measuring range up to meters, but also has a better immunity to the surroundings when comparing with displacement laser interferometer. To some extent, industrial fabrication is a symbol of development of a country. With the rapid development of industry, grating ruler is considered as the eyes of fabrication, and attracts incremental researchers to improve its performance. The measuring resolution needs to reach nanometer level and the measuring range gets longer and longer. In this dissertation, the key technologies of grating ruler are investigated. As is known, the grating ruler mainly includes five parts: light source, grating scale, optical structure, detectors and signal processing. Therefore, we improve the stability and resolution of the grating ruler according to these five parts. 1. The design, fabrication and evaluation of grating scale Grating scale is the key component of grating ruler. The uniformity of grating scale determines the accuracy of measurement. We describe two techniques to design the grating scale, including scalar diffraction theory and rigorous vector diffraction theory. As the grating scale used in our measurement should be with high diffraction efficiency at the incident angle close but not equal to the Littrow angle, the grating should be designed specially. After the grating scale being fabricated, the grating period uniformity needs to be evaluated. The classical techniques, such as optical diffraction technique and scanning microscopy, have been successfully used in measurement of line width of gratings. However, these techniques have some disadvantages of time consuming and high-cost when used for those grating scale with large grating period. What’s worse, they cannot provide the period information of the whole grating though most of them are with high accuracy. We proposed a novel technique based on the digital image correlation to measure the grating period. This technique is able to measure the periods of the whole grating with high accuracy, which should be interesting in evaluating the quality of gratings. 2. Two-degree-freedom grating interferometer based on Littrow configuration Grating interferometer is one kind of grating ruler that is able to measure displacement with high accuracy. Optical structure plays an important role in grating interferometer. A good optical structure should provide high resolution and high stability for the measurement system. We proposed an optical structure for grating interferometer based on the Littrow configuration. The different optical length is diminished to the least to enhance the ability of resisting disturbance. What is more, thanks to the signals processed independently for the two measuring light, the system is able to measure two dimensional displacement at the same time, which is very different from the classical grating interferometers. Usually, one dimensional measurement is based on the one dimensional grating scale, and two dimensional measurement is based on the two dimensional grating scale. Applying our optical structure, the grating interferometer provides two dimensional displacement based on one dimensional grating scale. That should be interesting in extending the applications of grating interferometer. 3. The grating interferometer with high optical subdivision The resolution is an important character for the measurement system. Grating interferometer is considered as the crucial tool to measure displacement with high resolution. The resolution of grating interferometer is dependent on the grating period, electronic subdivision and optical subdivision. For a certain grating scale, the grating period is a constant, and electronic subdivision is related to the signal process, the optical subdivision is related to the optical structure. The growing optical subdivision helps to obtain higher measuring resolution. We proposed several novel optical structures for the grating interferometers. That is able to increase the optical subdivision, resulting in high resolution. The installation errors of every optical components also be analyzed in theory. At last, we compare the measurement results obtained by the home-made grating interferometer and that by commercial displacement laser interferometer. The identical results verify the feasibility of the novel optical structures. 4. Signal acquisition and processing Signal acquisition and processing are the last steps for the displacement measurement. We analyze the principle of different structures for signal acquisition. That helps to improve the performance and analyze the error sources. At last, we introduce the circle fitting to decrease the installation error. |
| 学科主题 | 光学工程 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/30980]  |
| 专题 | 中国科学院上海光学精密机械研究所 |
| 作者单位 | 中国科学院上海光学精密机械研究所 |
| 推荐引用方式 GB/T 7714 | 卢炎聪. 光栅尺关键技术研究[D]. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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