| 摘要 |
<p>The invention relates to an optical system for forming an image on a concave spherical surface comprising, perpendicularly to the optical axis of the spherical surface, starting from the object side: a first elliptical plano-convex lens (L1) with convexity directed towards the object side; a second aspherical plano-concave lens (L2) whose radius of curvature decreases with distance from the axis, with concavity directed towards the image side, made of a material with a smaller Abbe number than that of the first lens; a parallel-faced plate (S1) on which bear the planar faces of the first and second lenses; a third aspherical plano-convex/concave lens (L3) exhibiting a convex shape in its central part and a concave shape at its periphery.</p> |
