The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 22, 2006
Filed:
Jun. 04, 2004
Mitsunori Toyoda, Tokyo, JP;
Osamu Tanitsu, Kumagaya, JP;
Mitsunori Toyoda, Tokyo, JP;
Osamu Tanitsu, Kumagaya, JP;
Nikon Corporation, Tokyo, JP;
Abstract
An illumination optical system having a more simplified structure forms various quadrupole-shaped secondary light sources with two-time rotational symmetry with respect to an optical axis. The apparatus can provide illumination conditions that differ in two perpendicular directions on a radiation-receiving plane. In order to form a secondary light source with a quadrupole-shaped light intensity distribution on an illumination pupil plane, a diffractive optical device is provided in which an entrance light beam is converted into four light beams, and a light beam having a shape of four points centered about the optical axis is formed in a far field. The diffractive optical device is provided with a first diffractive optical member that is rotatable about a first axis parallel to the optical axis, and a second diffractive optical member that is rotatable about a second axis parallel to the optical axis, and that is arranged adjacent to the first diffractive optical member. A refractive optical device having first and second refractive optical members accomplishes similar results.