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:
Dec. 25, 1990
Filed:
Feb. 22, 1989
Keiji Matsui, Ooguchi, JP;
Kabushiki Kaisha Okuma Tekkosho, Nagoya, JP;
Abstract
An averaged diffraction moire position detector has a pair of diffraction gratings. One of the gratings has two grating portions arranged with an offset of half a pitch of the transit portions and the non-transit portions for light. The intensities of light passing through respective grating portions are added to cancel any error component is displacement signals produced when two parts of, for example, a machine tool move. Another averaged diffraction moire position detector uses offset in phase of respective error components contained in the diffracted light of plus and minus of the same number-order. Thus, the intensities of respective diffracted light are added to cancel respective error components, resulting in correct displacement signals being produced.