Wide angle retrofocus objective lens - has 5 successive lens groups with positive and negative focal widths in alternation and defined optical parameters

摘要

The lens comprises 5 component gps. (S1...S5) positioned one after the other along an optical axis each contg. one or more lens elements. The component gps. exhibit positive and negative focal widths in alternation, starting with a positive focal width. The lenses of the first and second gp. each have a convex front surface and a common negative focal width, the 'Abbe' number for the second gp. being less than 44. The third lens gp. has convex outer lens surfaces and a refractive index of less than 1.63. The fourth lens gp. has concave outer lens surfaces. The fifth gp. has a convex rear lens surface. The ratios between the common focal width of the first 2 gps. and the thickness and focal width are defined by given inequalities. USE/ADVANTAGE - For use with liq. crystal display panel in high definition television. Focal distance of over 2.35 f is possible. Extensive correction of whole image faults.