基于液晶空间光调制器的复用透镜焦深延拓方法研究

发布时间：2018-03-08 12:46

本文选题：复用透镜　切入点：焦深延拓　出处：《湖北工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：长焦深的光学元件在激光直写、快速成形、激光雕刻、打孔、切割、焊接等工程领域具有广阔的应用前景。目前,虽然有多种方法能够实现长焦深,但在实际应用中仍然存在着许多技术瓶颈。液晶空间光调制器具有灵活的可编程特性,将其应用到长焦深光学元件的研究中,将赋予长焦深光学元件更多的灵活性和自主性。本论文研究了一种基于液晶空间光调制的复用透镜焦深延拓方法。主要研究工作包括:总结对比了几种常见的液晶空间光调制器相位调制测量方法,选用马赫—曾德干涉光路对XGA2型液晶空间光调制器的相位调制特性进行了测量。获得了干涉条纹图像,并通过图像处理结合最大概率原则的方法提取了条纹的相对移动量及周期,利用最小二乘多项式拟合的方法得到了液晶空间光调制器的相位调制特性曲线。研究了利用液晶空间光调制器加载菲涅尔透镜的原理,并对菲涅尔透镜的抽样问题以及衍射效率问题进行了分析。利用Matlab编程将多个不同焦距的菲涅尔透镜与液晶闪耀光栅镶嵌在一起,通过随机采样的方法同时写入到液晶空间光调制器上,根据每个透镜轴向焦点相互交叠的原则,延长了焦深,同时制作了焦深范围为1000mm~1040mm的复用透镜灰度图。基于Matlab仿真模拟了复用透镜聚焦实验,介绍了模拟实验实现的原理,并对仿真的结果进行了分析。搭建了多焦复用透镜聚焦实验光路,分别将复用透镜灰度图和单透镜灰度图加载到液晶空间光调制器上,通过CCD得到了不同位置处的聚焦光斑,并从聚焦光斑的大小和强度两个方面对实验结果进行了比较和分析。实验结果表明,相比于单透镜,复用透镜的焦深范围得到了有效的延长,并且在整个焦深范围内,其分辨率基本保持不变且与单透镜接近,验证了该焦深延拓方法的可行性。
[Abstract]:Optical elements with long focal depth have broad application prospects in laser direct writing, rapid prototyping, laser engraving, drilling, cutting, welding and other engineering fields. However, there are still many technical bottlenecks in practical application. The liquid crystal spatial light modulator has flexible programmable characteristics and is applied to the study of optical elements in the long focus depth. In this paper, we study a method of reusing lens depth extension based on liquid crystal spatial light modulation. The main research work includes: summarizing and comparing several kinds of common liquid. Phase Modulation Measurement method of Crystal Spatial Light Modulator, The phase modulation characteristics of XGA2 liquid crystal spatial light modulator are measured by using Mach Zende interferometer. The interference fringe images are obtained. The relative movement and period of stripes are extracted by image processing and maximum probability principle. The phase modulation characteristic curve of liquid crystal spatial light modulator is obtained by least square polynomial fitting. The principle of Fresnel lens loading with liquid crystal spatial light modulator is studied. The sampling problem and diffraction efficiency of Fresnel lens are analyzed. Several Fresnel lenses with different focal lengths are embedded with liquid crystal blazed grating by Matlab programming. The method of random sampling is used to write to the liquid crystal spatial light modulator at the same time. According to the principle that the axial focus of each lens overlaps with each other, the focal depth is prolonged. At the same time, the multiplex lens grayscale map with the focal depth of 1000mm and 1040mm is made. The focusing experiment of the multiplexed lens is simulated based on Matlab, and the principle of the simulation experiment is introduced. And the simulation results are analyzed. The experimental optical path of multi-focal multiplexing lens focusing is built. The grayscale map and single lens grayscale image are loaded into the liquid crystal spatial light modulator respectively, and the focusing spot at different positions is obtained by CCD. The experimental results are compared and analyzed in terms of the size and intensity of the focusing spot. The experimental results show that compared with the single lens, the range of focal depth of the multiplexed lens is effectively prolonged, and the range of focal depth of the multiplexed lens is extended effectively in the whole focal depth range. The resolution of the method is invariant and close to that of a single lens, which verifies the feasibility of the method.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN761;TH74

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