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. 06, 2007
Filed:
Mar. 19, 2004
Toshitaka Shimomura, Utsunomiya, JP;
Shingo Nihommori, Kawasaki, JP;
Miyako Mizutani, Kawasaki, JP;
Eric Herbert Altendorf, Edmonds, WA (US);
Joseph Daniel Tobiason, Woodinville, WA (US);
Toshitaka Shimomura, Utsunomiya, JP;
Shingo Nihommori, Kawasaki, JP;
Miyako Mizutani, Kawasaki, JP;
Eric Herbert Altendorf, Edmonds, WA (US);
Joseph Daniel Tobiason, Woodinville, WA (US);
Mitutoyo Corporation, Kawasaki, JP;
Abstract
A displacement measuring device including a scale, and an optical readhead including an index pattern and a light receiving element is provided. A bright/dark pattern arising from a scale grating is detected by the readhead to measure displacement. In various embodiments, a magnification of the pattern is adjusted by the spacing between at least a lens element, aperture element, and detection plane of the readhead. An aperture can be designed to provide a diffraction-limited telecentric imaging configuration that filters an image of the scale grating to provide a sinusoidal intensity pattern that supports highly interpolated measurements. An aperture dimension, selected in relation to the grating pitch and other parameters, can provide a desirable combination of readhead operating characteristics including one or more of a desired depth of field; degree of spatial filtering; and optical signal power.