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:
Feb. 10, 1998
Filed:
Dec. 27, 1994
Tetsuo Kikuchi, Tokyo, JP;
Nikon Corporation, , JP;
Abstract
An illumination optical apparatus for setting the illuminance on an illuminated object as high as possible at or below the upper limit of illuminance. When the illumination state changing unit changes the illumination state of illumination light, for example, when the numerical aperture is decreased to lower the illuminance on the illuminated object, the power supplied to the light source is increased; inversely, when the numerical aperture is increased to enhance the illuminance on the illuminated object, the power supplied to the light source is decreased so that the illuminance is kept at or below the predetermined upper limit. This can maintain the illuminance on the illuminated object high and nearly constant even with a change of the illumination state.