Patent ID: 11899371
Assignee: NIKON CORPORATION
Field: nan (nan)
Classification: CPC nan | IPC G

Claim 24:
25. A catoptric system having a reference axis and comprising:
a first pair of reflector elements that are symmetric to one another about the reference axis, each surface of the first pair of reflectors having a convex surface;
a second pair of reflector elements that are symmetric to one another about the reference axis, each surface of the second pair of reflectors having a concave surface, wherein reflecting surfaces of the reflector elements from the first pair and face reflecting surfaces of the reflector elements from the second pair; and
an illumination element disposed on the reference axis between the first pair of reflector elements and the second pair of reflector elements,
the catoptric system configured to:
receive, at the surfaces of the first pair of reflectors, optical radiation in a form of two diffracted beams of radiation delivered thereto from between the second pair of reflector elements, and
form an image of an object by irradiating an image plane with optical radiation after the optical radiation has been reflected from the surfaces of the second pair of reflectors and after the optical radiation has passed between the first pair of reflectors,
wherein the illumination element is situated to reflect an illumination radiation to the object, the two diffracted beams of radiation are generated at a substantially one-dimensional (1D) diffractive structure defined by the object in response to the illumination radiation received from the illumination element, and the illumination element is situated to block light passing between the two diffracted beams of radiation originating at the object.