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:
Aug. 23, 1994
Filed:
Jun. 05, 1992
Applicant:
Inventors:
Makoto Okai, Tokyo, JP;
Shinji Tsuji, Tokyo, JP;
Akio Ohishi, Tokyo, JP;
Motohisa Hirao, Tokyo, JP;
Hiroyoshi Matsumura, Iruma, JP;
Tatsuo Harada, Tokyo, JP;
Toshiaki Kita, Tokyo, JP;
Hideki Taira, Tokyo, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B32B / ; G03C / ; G02B / ;
U.S. Cl.
CPC ...
428167 ; 428172 ; 428212 ; 430-5 ; 430321 ; 359 34 ; 359290 ; 359321 ; 359569 ; 359575 ;
Abstract
A method of fabricating diffraction gratings wherein a photomask is arranged on a substrate which is coated with a photoresist, light is to be incident thereupon at an acute angle relative to the normal direction of the photomask, and a bright/dark pattern is formed on said photoresist by the interference of the transmission light that has passed through the photomask and the diffraction light. The invention further deals with a photomask used for the above method.