Nikon Corporation

The Institute of Physical and Chemical Research

Toyota School Foundation

Teruyoshi Tsunashima

Atsushi Shibayama

Kozo Ando

Kiyoshi Hayashi

Tamio Hara

A catadioptric lens (,) comprising, along an optical axis (AX), a first lens group (L,) having an objectwise concave annular incident surface (SI) upon which light from an object is first incident, and a most imagewise lens surface (,). The catadioptric lens further includes an annular main mirror (MM) arranged imagewise of the first lens group and having an objectwise concave reflective surface (R,) that reflects light objectwise. A secondary mirror (MS) is located objectwise of the annular main mirror and has an imagewise convex reflective surface (R,) that reflects light imagewise. The first lens group has a glass optical path from the incident surface to the main mirror to the secondary mirror and to the most imagewise lens surface of the first lens group. The catadioptric lens may also include a second lens group L,imagewise of the first lens group. The second lens group may include two or more lenses, and preferably includes a cemented doublet (L,, L,). The catadioptric lens also preferably satisfies one or more of a number of design conditions.

Catadioptric lens

Lens systems are disclosed having multiple focal lines and that are operable to form multiple narrow superimposable focal lines. The focal lines typically have linewidths of .ltoreq. approximately 10 .mu.m, formed from an incident light flux from a laser. The superimposed focal lines can have sufficient energy density to serve as a pumping-laser source for an X-ray laser. The lens systems comprise, axially from the incident light side, a wave-surface splitter and a focusing system. The wave-surface splitter splits the wave surface of the incident light into subfluxes. The focusing system focuses the subfluxes into respective linear focal lines that can be superimposed to form a combined focal line having very high energy density. The wave-surface splitter is preferably a prism having multiple facets with respective prism angles; the focusing system preferably comprises multiple cylindrical lenses each having a generation line perpendicular to the ridge lines separating the facets of the prism.

Lens system with multiple focal lines

A zoom lens comprises a first lens group having a positive refractive power and a second lens group having a negative refractive power sequentially from an object to be photographed. The first lens group comprises an aperture, a front group including at least two lens components having a positive refractive power, and a lens component which has a negative refractive power and an object-side lens surface of which has a concave surface directed toward an object side, and a rear group located nearer to an image than the aperture and including at least one lens component having a positive refractive power. The front group is located nearer to the object than the aperture and has a positive refractive power as a whole. The second lens group comprises at least one lens component having a positive refractive power and at least two lens components having a negative refractive power. A relative distance between the first and second lens groups is changed to perform zooming.

Growing community of inventors

Tokyo, Japan

Teruyoshi Tsunashima