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:
Jan. 22, 2008
Filed:
Nov. 04, 2004
Shuzo Seo, Saitama, JP;
Shinichi Kakiuchi, Saitama, JP;
Shuzo Seo, Saitama, JP;
Shinichi Kakiuchi, Saitama, JP;
PENTAX Corporation, Tokyo, JP;
Abstract
A light-amount control device includes a plurality of lighting units each of which emits light for illuminating a photographing area of a photographing optical system. Further, the light-amount control device includes a peripheral light amount data calculator and a lighting unit controller. The peripheral light amount data calculator calculates a peripheral light amount data defining ratios of light emission intensities for the lighting units, to make the illuminance of an image plane of a standard object that has a flat surface being perpendicular to the optical axis of the photographing optical system and having a constant reflecting light ratio, constant when the standard object is illuminated by the lighting units. The image plane is formed by reflected light from the surface of the standard object that enters the photographing optical system. The lighting unit controller controls the lighting units so that the intensity of light at a wider illuminating angle to an optical axis of the photographing optical system becomes higher, based on the peripheral light amount data.