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:
Jun. 05, 2007
Filed:
Jun. 20, 2005
Eric H. Altendorf, Edmonds, WA (US);
Eric H. Altendorf, Edmonds, WA (US);
Mitutoyo Corporation, Kawasaki-shi, JP;
Abstract
An illumination configuration for imaging-type optical encoders is provided. The illumination configuration generates uniform brightness images of scales and two-dimensional structures when utilizing telecentric imaging optics in the encoder readhead. In one embodiment, a desirable uniform irradiance distribution is created across the field of view by illuminating with a collimated or quasi-collimated beam, but insuring that the illumination is sufficiently incoherent that potential self-images arising from periodic structures on the scale are suppressed. In one embodiment, the ratio of an effective emitter size to a focal length of the collimating lens falls within a selected range, so as to assure relatively uniform illumination across the field of view and still provide sufficiently incoherent illumination. In another embodiment, a diffuser is placed over the collimating lens, which assists in producing uniform illumination even when the direction of illumination varies relative to the scale due to misalignment between the readhead and the scale surface.