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:
Mar. 22, 1977
Filed:
Dec. 09, 1974
Tatsuo Harada, Fuchu, JA;
Shigeo Moriyama, Kokubunji, JA;
Toshiaki Kita, Tokyo, JA;
Hidenori Yamaguchi, Hachioji, JA;
Hitachi, Ltd., , JA;
Abstract
A tool for ruling grating grooves is reciprocated on a diffraction grating blank with the tool being restrained within a plane inclined at an arbitrary angle relative to a plane lying in contact with one point on a spherical concave of the diffraction grating blank. Translation for a variable pitch-groove spacing which changes as a function of the groove number or groove position is imparted to the diffraction grating blank in interlocking relationship with the reciprocation, thereby mechanically ruling the desired sphere of the grating blank with the grating grooves, whereby a concave diffraction grating which forms diffracted light of a specific wavelength into a completely stigmatic image at high diffraction efficiency can be manufactured.