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:
Sep. 03, 1996
Filed:
Mar. 08, 1995
Yoshihiro Hisa, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
In a method of producing a .lambda./4-shifted diffraction grating, an image reversible resist is deposited on a substrate, the image reversible resist is exposed to an interference pattern having an intensity so that the resist is not dissolved when developed, the resist on a first region of the substrate is exposed to an interference light pattern so that only portions of the resist exposed to crests of a light intensity pattern in the interference exposure process are dissolved when developed, the resist on the first region is developed, portions of the resist on the first region remaining after the developing are exposed so that image reversal occurs in these portions when subjected to image reversal baking, the resist on a second region of the substrate is exposed to an interference light pattern so that only portions of the resist exposed opposite crests of a light intensity pattern are image reversed when subjected to image reversal baking, the resist on the first and second regions is subjected to image reversal baking, and the resist on the first and second regions is exposed and developed to remove portions in which image reversal did not occur, thereby forming a mask for a .lambda./4-shifted diffraction grating to be formed in the substrate.