WANG ZHIJING, LI YUANKANG, JIANG JIANZHONG. A lithographic optical system having only one symmetric plan[J]. Acta Optica Sinica, 1984, 4(4): 322
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Optical system having only one symmetric plan is difficult to correct aberrations. We consider the imaging properties of ellipsoid near the focus and of concentric spheric surface,, and appropriately combine it. An optical system having field diameter 50~ 70mm, N. A. 0.15-0.1, and imago qualities near diffraction limit is obtained.