大视场反射式施密特光学系统设计与检测

Optical design and detection for reflective Schmidt system with large field of view

  • 摘要: 大视场、低成本、高性能天文望远镜是当前研究和开发的热点。基于像差平衡原理,在正入射施密特矫正板基础上推导出斜入射反射式施密特矫正板方程,针对焦距1 700 mm,成像视场角4°,波段为0.4 μm~0.9 μm,F数为4.25的光学系统,求解出施密特矫正板方程,并作为初始结构参数代入Zemax软件进一步优化。设计结果表明,在全视场范围内,该系统在奈奎斯特频率100 lp/mm处的调制传递函数MTF大于0.35,畸变小于2.5%,成像质量达到了衍射极限。优化设计后施密特矫正板与最近球面最大偏差为0.005 mm,采用特制的补偿器结合干涉仪可完成面形高精度检测。该施密特系统的设计为大视场、宽波段天文望远镜的开发提供了参考。

     

    Abstract: The astronomical telescope of large field of view, low-cost and high-performance is the focus of current research and development. According to the aberration balance principle, the oblique incident reflective Schmidt correction plate equation was derived based on the normal incident Schmidt correction plate. For an optical system with the focal length of 1 700 mm, the imaging field angle of 4°, the operating wavelength of 0.4 μm to 0.9 μm, and the F number of 4.25, the Schmidt correction plate equation was solved and further optimized by using ZEMAX software as the initial structural parameter. The design results show that, the modulation transfer function (MTF) of this system is more than 0.35 at the Nyquist frequency of 100 lp/mm in the full field of view, and the distortion is less than 2.5 %, which indicates that the imaging quality is close to the diffraction limit. After the optimized design, the maximum deviation between Schmidt correction plate and near spherical surface is 0.005 mm, and the special compensator can complete the surface shape high-precision detection combined with the interferometer. The design of the Schmidt system can provide references for the development of astronomical telescopes with large field of view and wide spectrum.

     

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