Condenser optical system and illumination optical apparatus provided with the optical system
AssigneeNikon Corporation
InventorsYutaka Suenaga, Kouichi Hiraga, Masato Kumazawa
Life of this patent
Estimating the term…
Abstract
A condenser optical system obtains a predetermined, desired optical characteristic in a simple structure having a small number of lenses. A condenser optical system having an entrance focal plane and an exit focal plane, and that forms an image at the exit focal plane of an object located at the entrance focal plane, includes in order from an object side, a first lens group having a negative lens having a concave surface that faces the object side, a second lens group having a positive lens, and a third lens group. The first lens group has at least one aspherical lens surface.
Claims12
A condenser optical system having an entrance focal plane and an exit focal plane, and that forms an image at the exit focal plane of an object located at the entrance focal plane, the condenser optical system comprising:
- in order from an object side, a first lens group having a negative lens having a concave surface that faces the object side, a second lens group having a positive lens, and a third lens group, wherein the first lens group has at least one aspherical lens surface.
Dependencies are inferred from the claim text.