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. 01, 1987
Filed:
Oct. 03, 1985
Toshiaki Kita, Nishitama, JP;
Tatsuo Harada, Fuchu, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In a method of producing diffraction gratings by feeding either one of a blank or a groove-ruling tool by an amount consisting of the amount of constant transference and the amount of variable transference that is added thereto, or subtracted therefrom, while reciprocally moving the other one of said blank or said groove-ruling tool, in order to rule grooves of irregular intervals on said blank, a method of producing varied line-space diffraction gratings wherein the region of ruling is divided into a plurality of small regions so that the difference between a maximum value and a minimum value of distance between grooves becomes smaller than a predetermined value, and the amount of constant transference is set to the nearly equal to an average distance between grooves in each of said small regions.