In the development of a high-precision vertical Fizeau interferometer with a 300-mm aperture, the deformation of the transmission flat because of clamping and gravity must be considered. In this paper, we proposed a ring-point support scheme for the deformation calibration of a large-diameter transmission flat. The calibration theory of the ring-point support system with elastic deformation was derived. The changes in the surface and stress field of the transmission flat were analyzed quantitatively by finite element method modeling, leading to the optimization of the support structure. To validate the proposed calibration approach, we performed an absolute test of the transmission flat using a liquid reference. The test result was compared to a measurement of the Zygo interferometer demonstrating the effectiveness of the proposed ring-point support design. Finally, with the iterative deformation calibration, the accuracy of the transmission flat reached λ/25 (Peak Valley, PV) for a 300-mm aperture.

中文翻译：

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通过300 mm孔径的Fizeau垂直干涉仪上的环形点支撑对传输平面进行迭代变形校准

在开发具有300 mm孔径的高精度垂直Fizeau干涉仪时，必须考虑由于夹紧和重力而导致的传输平面变形。在本文中，我们提出了一种环形点支撑方案，用于大直径传动系统的变形校准。推导了具有弹性变形的环形点支撑系统的标定理论。通过有限元方法建模，定量分析了传动平板的表面和应力场的变化，从而优化了支撑结构。为了验证建议的校准方法，我们使用液体参考液对变速箱进行了绝对测试。将测试结果与Zygo干涉仪的测量结果进行了比较，证明了所提出的环形点支撑设计的有效性。最后，通过迭代变形校准，对于300 mm的孔径，传输平面的精度达到了λ/ 25（Peak Valley，PV）。