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. 04, 2003
Filed:
May. 10, 2000
Applicant:
Inventors:
Hiromu Mukai, Kawachinagano, JP;
Shigeto Ohmori, Kawachinagano, JP;
Assignee:
Minolta Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03B 1/324 ; G03B 1/306 ;
U.S. Cl.
CPC ...
G03B 1/324 ; G03B 1/306 ;
Abstract
A focusing screen for use in a camera has a diffusive surface having a plurality of random pattern cells of one or a plurality of types arranged two-dimensionally so as to form a macroscopically flat surface. The random pattern cells are each composed of a plurality of minute rectangular elements having one of two to eight types of heights, and the individual rectangular elements are arranged irregularly so as to constitute a plurality of types of diffraction gratings having different grating pitches.