查询词典 diffraction grating

We expect it will benefit the industry field to break through the optical measuring limits at present by offering some new ideas. Optical measuring research based on moire interferometry has developed for several decades. The main idea of this research is to utilize the moire effect caused by two superimposed gratings of identical or similar spatial frequency. One is the reference grating and it is a virtual grating created by a computer program in this research; The other grating is the image of grating projected on the measured surface by the DLP projector, and this grating will distort because of the different sloped profile of the surface. To superimpose the program-created grating and the captured distorted grating will derive the so-called moire effect. This research combined the basic theory of optical interferometry and moire effect to project the different phases of the projected grating fringes by the phase-shifting method and compute the principal value of arguments between -π,π. In the end, the phase unwrapping program based on discrete Fourier transform of solving PDEs is used to unwrap the phase of the measured surface, and finally the surface profile is derived by the optical measuring system.

以叠纹干涉术为基础的光学检测研究之发展早已行之有年，而在本研究中所采用的投影叠纹法(Projection moiré)之主要精神在於藉由两道空间频率相近或相同的光栅相互叠加而成的效应，其中一道为参考光栅，而本研究中的参考光栅是以程式产生可调整不同空间频率的虚拟光栅；另一道则为投影至待测物表面的光栅影像，而在起伏高度不一的待测表面上的光栅影像会受到待测物表面起伏状况不同而在观测方向产生光栅投影条纹影像的歪曲变形，将电脑产生的参考光栅与由影像撷取装置所获取投影於待测物表面的光栅影像作叠合，便会产生所谓的叠纹效应；利用基本的光学干涉理论与叠纹效应结合，本研究中以相移法来改变投影於待测表面的光栅相位，再以相移法的理论反运算出在带有待测面各点高度资讯之介於-π，π相位主幅角，再以离散傅立叶转换解偏微分方程的相位重建程式还原待测面的相位值，以得知待测面之表面轮廓。

Open Linear Encoder includes main grating scale and optical encoder head. This optical encoder head includes LED light source, optical detector module, and secondary phase-grating. LED light will pass through the plano-convex lens and produces parallel light. As the parallel light pass through secondary grating, the quadratic image display on the main grating scale. And the Moire interference will be reflected from the main grating scale and detected by optical detector module, as there is a relative shift between the main and secondary grating. From detecting the periodic sinusoidal signal with phase difference 90°, the period represents the grating pitch, using the counter to detect the number of periodic signals to get the displacement, and we can adapt the technology of electron subdivide further to increase the resolution of measurement .

反射式光学尺包括主光栅尺及光学读头，光学读头包含LED光源、光侦测器模组及相位式副光栅，LED光源经平凸透镜，产生平行光穿透副光栅后，副光栅之二次成像投射在反射主光栅尺上，当主、副光栅因相对运对产生之Moire干涉经主光栅尺反射至光电检测器，检出相位差90°之周期性弦波讯号，其周期代表栅距，因此可用计数器检出周期性讯号数目得到位移量，可进一步采用电子细分割技术提高解析度。

X-ray diffraction is one of the most common and efficient ways to measure a superlattice structure. This dissertation displays the detail results for characterization of Ge〓Si〓/Si superlattices by x-ray diffraction (including x-ray small angle diffraction and double crystal diffraction). It was found, when the growth temperature is lower, the intensities of xray small angle diffraction peaks are modulated by a periodical function, which indicates that both sets of interfaces of the superlattice is highly flat; when the growth temperature is higher, the diffraction peak intensities are simply decay with the increase of diffraction vector, which indicates that one set of interfaces is highly flat but another is not; when the growth temperature is very high, the diffraction peaks are reduced more rapidly, which indicates that both sets of interfaces are not ideal.

本文详细介绍了用X-射线衍射（包括X-射线小角衍射和双晶衍射）方法对Ge〓Si〓/Si超晶格结构特性测试的结果，尤其是发现，当Ge〓Si〓/Si超晶格的生长温度较低时，X-射线小角衍射谱峰的强度随着衍射波矢的增加而周期性调制，表明超晶格的两套界面都十分平整；当生长温度较高时，Ge〓Si〓Si超晶格的X-射线小角衍射谱峰的强度随着衍射波矢呈简单的衰减变化，对应于超晶格内有一套界面不平整的情况；当生长温度进一步提高时，X-射线小角衍射峰明显减少，表明超晶格内两套界面都不理想。

Based on Matlab, simulation program of grating diffraction is complied. By changing adjustable parameters, computer simulations of white light interference and diffraction experiments (i. e., grating diffraction, single slit and double-slit diffraction, double-beam and multi-beam interference experiments) can be achieved.

基于Matlab软件编写出白光光栅衍射仿真程序，通过改变可调参数实现白光干涉、衍射实验（包括：光栅衍射、单缝及双缝衍射、双光束及多光束干涉等）的计算机仿真。

The camera length of electron diffraction in transmisson electron microscopy is one of the main technical parameters in designing electron microscope and the electron diffraction analysis to microcrystal sample. According to Bragg law, the formula of calculating TEM electron diffraction camera length is derived from the research on the ray path of electron diffraction images in TEM and the comparison on electron diffraction with ordinary electronic diffractometer. The difference of physical significance of electron diffraction camera length between TEM and ordinary electronic diffractometer is discussed.

透射式电子显微镜(Transmisson Electron Microcopy， TEM)中的电子衍射相机长度，是电子显微镜设计和对微晶体样品进行电子衍射分析的主要技术参数之一依据布拉格定律，经对TEM中电子衍射成像光路的探讨与研究，并通过TEM与普通电子衍射仪的电子衍射的对比分析，导出了TEM电子衍射相机长度的精确计算公式，阐述了TEM和普通电子衍射仪的电子衍射相机长度所表征的物理意义的区别。

With given parameters of the fiber grating, the transmission spectrum of the long-period fiber grating was obtained by simulation with Matlab. As a result, the position of the resonant wavelength of the long-period fiber grating is decided by the grating′s period. The attenuation changes with the length and refractive index of the grating.

在设定的光纤光栅参数条件下，通过Matlab进行模拟得到了最终需要的长周期光纤光栅透射谱，并由此得出：长周期光纤光栅谐振波长出现的位置主要由光栅的周期决定，损耗大小可以通过调节光栅长度和折射率来实现。

Base on the analysis of the grating linear displacement measurement theory,t he measure errors especially the subdivision error of the grating scale,this paper focuses on the theory of switch and merge of dual grating scales'signals,builds the design criteria of high speed high precision displacement measurement by using dual grating sales,designs the switch picking reference with high precision and fast switch and merge method,analyses the errors brought in by switch and merge of the duals grating scales.

针对光栅尺的电子细分信号具有细分误差的特性，本文提出了对莫尔条纹信号不细分的方法以提高双光栅尺信号切换合成值的精度。经过对双光栅计数切换基准、切换与合成特征和规律的探讨，本文设计了实现双光栅尺双重测量、计数值切换合成法的硬件电路，主要通过可编程芯片FPGA，设计了双光栅尺信号处理的各电路模块，如双光栅尺信号四倍频辨向模块、速度判断模块、切换模块、计数值合成处理模块。

Laser-based metrology and grating-based metrology are two main ultra-precision tools of dimension measurement. However, very few research work has been done on grating-based nanometrology compared with laser-based nanometrology till now because many people, including some grating researchers and specialists, hold the idea that the accuracy of grating-based measurement is lower than the laser's and can only reach micrometre or sub-micrometre level. They consider that it is unfeasible to get nanometer-scale accuracy using grating-based sensors.

激光技术和光栅技术是毫米级以上量程的精密几何量测量的两种最主要手段，目前，用激光进行纳米测量的研究已经很多，但光栅纳米测量技术的研究却很少；很多人，包括很多光栅研究者和测量专家，都认为，光栅测量的精度不如激光，其精度还只是停留在微米量级上，用光栅来进行更高精度的测量以至纳米测量是难以实现的。

In aspect of investigation on the binary phase splitting grating, Dammann grating, rectangle grating and also coordinate-phase modulate grating have been studied respectively. Detail analysis shows that the grating phase angle can inflect greater than coordinate to the splitting efficiency and equality rate.

在对二元位相型光学分束光栅的研究方面，在本论文对Dammann光栅、矩形孔径光栅以及坐标位相调制型光栅分别进行了研究，通过对光栅设计参数的变化对分束效率、分束均匀度的影响的分析可以发现光栅位相角对分束效率及分束均匀度的影响要比突变点坐标的影响大得多。

Based on the principle of grating diffraction, by using television measuring system to measure the offset between the imaging of incident laser and the optical axis to confirm the angle of incidence and the angle of diffraction of the grating, a method of measuring incident laser wavelength in far field with grating is brought up.

依据光栅衍射原理，采用电荷耦合器件CCD作为探测器，通过测量入射激光成像点在电视靶面坐标系中的脱靶量，确定光栅的入射角和衍射角，提出了一种利用固定式平面反射光栅测量远场未知方位入射激光波长的方法。

The teacher likes the honeymouthed little girl very much.

老师很喜欢这个嘴甜的小姑娘。

Mr. Notker Bien's interests are traveling, spending quality time with the family and long-distance-running.

诺特卡·柏恩先生热爱旅游，长跑，以及和家人一起共度美好时光。