【作者】 刘东；

【导师】 杨甬英；

【作者基本信息】 浙江大学 ， 光学工程， 2010， 博士

【摘要】 由于非球面比球面可以提供更大的自由度,所以在光学系统中使用非球面可以缩小系统整体外形尺寸,减轻系统重量,改善像质等,从而提高系统的整体性能。然而,由于非球面形状及光学特性各异,非球面检测系统历来都是个难题。非球面的检测方法很多,主要有零位干涉检测法、非零位干涉检测法、轮廓法等。零位干涉检测法中的零位补偿透镜法及计算全息法等都是“一对一”型检测,虽然精度较高但无法实现通用化检测,且检测周期长,造价高；仅针对二次曲面的无像差点法需要至少一块口径大于被测非球面的辅助镜,虽具有一定通用性但辅助镜也极大地限制了其的应用。轮廓法的检测效率较低,并且接触式轮廓仪很容易将被测表面划伤。目前的非零位检测法,如长波长法、双波长法、剪切法等虽然一定程度上可以实现通用化检测,但由于非零位检测具有较大的回程误差,而大多都没有进行非零位误差校正,故精度较低。本论文主要研究可用于非球面通用、数字化的非零位干涉体系、波前补偿、面形重构、测量数据及图像处理技术等。该研究对非球面检测技术,特别是非球面的非零位通用、数字化检测技术具有重要的意义。主要研究内容有：论述了非球面检测,特别是通用化、数字化检测技术在光学测试及仪器等领域的重要意义。对国内外各种非球面加工及检测技术做了系统分析,提出了研究可用于非球面通用化、数字化检测技术的必要性。针对非零位检测中返回波前往往具有较大畸变的特点,提出了利用部分零位透镜对一定范围内非球面进行部分补偿。详细论述了部分零位镜的设计过程,分析了部分零位镜的特性,并进而建立一整套可实现非球面通用化检测的部分零位镜体系。研究了非球面非零位干涉检测中的回程误差问题。详细分析并推导了回程误差的表现形式及其对检测结果的影响。提出了初步校正非球面非零位检测中的回程误差的方法,并进行了实验验证。建立了能对被测非球面状态进行全面描述的状态矩阵,提出了基于最小二乘算法的非球面面形逆向迭代优化重构技术。并通过大量仿真计算,研究了该重构技术在面形检测方面的能力。提出了可用于非球面通用、数字化检测的光路布局及处理流程。对整个检测系统进行了系统建模,并通过大量计算机仿真实验,分析了应用逆向迭代优化及部分零位镜补偿进行数字化非球面非零位检测的误差问题,为实际检测系统的建模精度控制提供了有力指导。建立了基于Twymann-Green干涉体系的实验装置,对实际口径为159mm,顶点球半径为818.952mm的抛物面进行了检测,精度RMS值优于1/30波长,达到了预期的效果,并对整个处理过程进行了误差分析。对本文所做工作进行了总结,并分析了目前研究中存在的不足之处,对下一步的研究方向及方法提出了建议。更多还原

【Abstract】 Aspherics can provide more degrees of freedom for aberration control. Use of aspherics helps to reduce the system size and weight while improving image quality. But due to their varieties of shapes and optical characteristics, aspheric testing has always been a great challenge for optical researchers.There are a good deal of aspheric testing methods, null interferometric test, nonnull interferometric test, profilometer, etc, for instance. Null compensator method and computer generated holograms method, which belong to null test, require one unique null optics for one asphere. They can both obtain high accuracy measurement, but the challenge in design, fabrication and certification of the null optics greatly limit their application. Aberration free methods, which employ auxiliary reflecting mirror, can perform general test for conics. However, the auxiliary mirror usually should have larger aperture than the test aspheric, and its surface figure limits the overall test accuracy. The profilometer is time consuming and also has the danger of damage the surface of the test aspheric. Nonnull tests, which employ long wavelength, multi-wavelength, shearing methods, etc, can also perform general test. But the retace error with nonnull configuration can greatly reduce the test accuracy.This dissertation mainly research on a general & digitizing nonnull interferometric aspheric testing system, include wavefront compensation, figure reconstruction, experimental data and image processing, etc. This research is of great contribution for aspheric testing, especially the general & digitizing aspheric testing method. The content of this dissertation include:After review of the various applications and the current fabrication methods of the aspherics, there is also a review over the current aspheric testing methods. And these reviews reflects the necessity of establishing a general & digitizing aspheric testing system.A type of novel partial null lens(PNL) is proposed to compensate for a range of aspherics. The design process of the PNL is discribed in detail and also the characteristics of the PNL are analyzed. The idea of using a series of PNLs to compensate for a larger range of aspherics is proposed and realized.The retrace error in nonnull interferometric aspheric testing system is analyzed in detail. The performance and its influence to the testing result are also analyzed and the correcting method is present.A matrix is proposed to represent the status of the aspheric under test. A reverse optimization figure reconstruction(ROR) process is proposed, which is based on system modeling and employs reverse optimization to reconstruct the figure of the aspheric form the wavefront detected on the detector. The performance of the ROR process is analyzed with lots of simulation.An interferometric system, which employs partial null lens and reverse optimization reconstruction process, is proposed to perform general aspheric testing. The system layout and figure construction process are present. System modeling and error analysis basing on the system model are also carried out. The error analysis provides important information for the modeling accuracy control of real experiment system.The validation experiment of the general & digitizing interferometric aspheric testing system has been established and the testing experiment for real paraboloid of 159mm aperture and 818.952mm vertex radius has been carried out with an accuracy of 1/30wave RMS. This dissertation is of great value for the accuracy enhancement of nonnull general aspheric testing.更多还原