Achromatic aplanatic condenser

An achromatic aplanatic condenser having a numerical aperture of 1.30 which is well corrected for spherical and chromatic aberrations and capable of uniformly filling a field of about 2.4mm in diameter which comprises, a double convex doublet consisting of a double convex singlet cemented to a concavo-convex singlet as the first component, a meniscus lens as the second component and a convex plano doublet as the third component all being aligned along an optical axis and having a front pupil plane external to said condenser, having the following parameters:

• ______________________________________ Refrac- Thick- tive Abbe Lens Radius ness Space Index No. ______________________________________ S.sub.1 = 1.526 R.sub.1 = 38.54 T.sub.1 = ND.sub.1 = .gamma..sub.1 = 8.73 1.6203 60.3 I R.sub.2 = 24.33 t.sub.2 = ND.sub.2 = .gamma..sub.2 = 1.50 1.786 25.5 R.sub.3 = -169.084 S.sub.2 = 0.10 R.sub.4 = 13.48 II T.sub.3 = ND.sub.3 = .gamma..sub.3 = 4.77 1.6203 60.3 R.sub.5 = 32.96 S.sub.3 = 0.10 R.sub.6 = 7.77 T.sub.4 = ND.sub.4 = .gamma..sub.4 = 6.13 1.651 55.8 III R.sub.7 = 00 T.sub.5 = ND.sub.5 = .gamma..sub.5 = 4.12 1.786 25.5 R.sub.8 = 00 ______________________________________
• wherein the values for radii, thicknesses, and air spaces are in mm and the refractive indices and Abbe numbers are absolute values.