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:
May. 28, 2013
Filed:
Jun. 22, 2011
Hirohisa Tanaka, Kumagaya, JP;
Hiroyuki Hirota, Sagamihara, JP;
Hirohisa Tanaka, Kumagaya, JP;
Hiroyuki Hirota, Sagamihara, JP;
Nikon Corporation, Tokyo, JP;
Abstract
According to one embodiment, an illumination optical system comprises an optical integrator which forms a secondary light source on an illumination pupil plane in an illumination optical path of the illumination optical system with incidence of exposure light from a light source device thereinto; a first transmission filter arranged in an optical path of the exposure light emitted from a first surface illuminant of the secondary light source and having a transmittance characteristic varying according to angles of incidence of the exposure light; a second transmission filter arranged in an optical path of the exposure light emitted from a second surface illuminant of the secondary light source and having a transmittance characteristic varying according to the angles of incidence of the exposure light; and a rotation mechanism which rotates the first and second transmission filters so as to vary an angle of inclination thereof relative to the optical axis of the illumination optical system.