动态生成理想干涉点源阵列的点源发生器的研究

发布时间：2018-06-05 10:59

本文选题：自由曲面 + 点源发生器　；参考：《南京理工大学》2017年硕士论文

【摘要】：光学自由曲面具有能够改善光学系统成像质量、减少透镜使用数、缩小系统尺寸等优点,使其在照明、航空航天、生物医疗等领域被广泛使用。但是由于其表面梯度变化较大,使得其面形检测成为光学领域的一大难题。目前,因倾斜波面干涉法(Tilted-Wave-Interferometry,简称TWI)具有检测精度高、通用强、测量动态范围广等优点,使其在自由曲面面形测量方面备受关注。点源发生器是倾斜波面干涉系统的关键器件,产生用于补偿待测件局部梯度的球面波点源阵列。目前,国内外研究的倾斜波面干涉系统中,点源发生器由针孔阵列、透镜阵列和掩膜板构成。但是由于构成透镜阵列的单透镜具有球差,造成单透镜出射的光束不是理想球面波,进而导致倾斜波面干涉系统在测量中引入误差;其次,透镜阵列制作完成后,无法根据被测件的面形动态生成点源阵列,制约倾斜波面干涉系统的检测通用性。本文提出了基于光纤阵列的点源发生器的新方案,解决基于透镜阵列的点源发生器的上述问题。研究了基于光纤阵列的点源发生器的设计方法,并研制了各个关键器件,制作了用于倾斜波面干涉系统的光纤阵列型点源发生器。为了保证倾斜波面干涉系统的相干性,在设计基于光纤阵列的点源发生器时采用保偏技术,保证点源发生器出射的任意两束球面波之间的相干性。本文设计了基于菲索干涉原理的相干性检测装置,对实际研制的光纤阵列型点源发生器的相干性进行了测试,证明该器件的相干性符合倾斜波面干涉系统的要求。本文对光纤阵列型点源发生器的点源间距误差对倾斜波面干涉系统的影响规律做了仿真分析,得出结论为:纤芯间距误差必须控制在15μm以内才能使引入TWI系统的波面误差小于λ/10。同时设计并搭建了光纤阵列纤芯间距测量系统,采用成像法获得点源发生器出射两束光的光斑图。利用椭圆拟合方法来确定光斑中心位置并计算纤芯间距,得到研制的点源发生器的纤芯间距误差为1.75μm,满足了倾斜波面干涉系统的精度要求。本文分析了基于光纤阵列的点源发生器的任意两个点光源之间的初始光程差对倾斜波面干涉系统测量结果的影响。设计并搭建了基于小数重合法的全光纤马赫曾德干涉测量系统,对实际研制的光纤阵列型点源发生器的各个点源之间由于光纤长度不一致引起的初始光程差进行了测量。计算出相应的误差数据矩阵,作为固有误差引入到倾斜波面干涉系统的误差模型中,以消除点源之间的光程差对TWI系统测量精度的影响。
[Abstract]:Optical free-form surface has the advantages of improving the imaging quality of optical system, reducing the number of lens used and reducing the system size, which makes it widely used in the fields of lighting, aerospace, biomedicine and so on. However, due to the large change of surface gradient, the surface shape detection becomes a difficult problem in the field of optics. At present, Tilted-Wave-Interferometry (TWI) has many advantages, such as high detection accuracy, strong generality and wide dynamic range, so it has attracted much attention in free-form surface measurement. The point source generator is the key device of the tilted wave surface interference system, which produces the spherical wave point source array to compensate the local gradient of the measured part. At present, the point source generator is composed of pinhole array, lens array and mask board. However, due to the spherical aberration of the single lens which constitutes the lens array, the beam emitted by the single lens is not an ideal spherical wave, which leads to the introduction of errors in the measurement of the slanted wave surface interferometer. Secondly, after the lens array is made, The point source array can not be dynamically generated according to the surface shape of the measured piece, which restricts the detection generality of the tilted wave surface interference system. In this paper, a new scheme of point source generator based on optical fiber array is proposed to solve the above problems of point source generator based on lens array. The design method of point source generator based on fiber array is studied, and the key devices are developed. The optical fiber array type point source generator for tilted wave surface interference system is fabricated. In order to ensure the coherence of the tilted wave surface interference system, the polarization maintaining technique is used in the design of the point source generator based on fiber array to ensure the coherence between any two spherical waves emitted by the point source generator. In this paper, a coherence detection device based on Fresso interference principle is designed, and the coherence of the fiber array type point source generator is tested. It is proved that the coherence of the device meets the requirements of tilted wave surface interference system. In this paper, the influence of point source spacing error of fiber array type point source generator on tilted wave surface interference system is simulated and analyzed. It is concluded that the error of fiber core spacing must be controlled within 15 渭 m in order to make the wavefront error of TWI system less than 位 / 10. At the same time, an optical fiber array core spacing measurement system is designed and built, and the spot pattern of two beams emitted from the point source generator is obtained by imaging method. Using the ellipse fitting method to determine the position of the spot center and calculate the fiber core spacing, the error of the fiber core spacing of the developed point source generator is 1.75 渭 m, which meets the precision requirement of the tilted wave surface interference system. In this paper, the influence of the initial optical path difference between any two point light sources of a point source generator based on fiber array on the measurement results of a tilted wavefront interferometric system is analyzed. An all-fiber Mach Zende interferometric system based on fractional multiple method is designed and built. The initial optical path difference caused by the inconsistency of fiber length among the various point sources of the fiber array type point generator developed in practice is measured. The corresponding error data matrix is calculated and introduced into the error model of tilted wave surface interference system as inherent error to eliminate the influence of optical path difference between point sources on the measurement accuracy of TWI system.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH74;TN253

【相似文献】