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:
Jun. 24, 1997
Filed:
Aug. 23, 1994
Applicant:
Inventors:
Assignee:
Sharp Kabushiki Kaisha, Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ; G03B / ; G03B / ;
U.S. Cl.
CPC ...
355 71 ; 355 53 ;
Abstract
A spatial filter used in a reduction-type projection printing apparatus includes a central region through which a light beam passes at transmittance of at most a prescribed value, a substantially transparent peripheral region which surrounds the central region, and a phase shifter for producing phase difference of 180.degree. between light beams passing through the central region and the peripheral region.