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:
Feb. 25, 2014
Filed:
Oct. 21, 2010
Emi Kaneko, Kanagawa, JP;
Taizo Nakamura, Tokyo, JP;
Tatsuya Nagahama, Kanagawa, JP;
Atsushi Usami, Kanagawa, JP;
Emi Kaneko, Kanagawa, JP;
Taizo Nakamura, Tokyo, JP;
Tatsuya Nagahama, Kanagawa, JP;
Atsushi Usami, Kanagawa, JP;
Mitutoyo Corporation, Kawasaki, JP;
Abstract
A photoelectric encoder in which light emitted from a light source is modulated by an optical grating and the modulated light is detected by a light receiving element, includes a one-side telecentric optical system which forms an image of the light modulated by the optical grating. The imaging optical system has an aperture through which part of the light modulated by the optical grating is allowed to transmit, the aperture having a size which is required when a cutoff spatial frequency that is a spatial frequency indicating a resolution limit of the imaging optical system due to the light emitted from the light source has a value between a fundamental spatial frequency of the optical grating obtained by a Fourier transformation and a second harmonic of the fundamental spatial frequency.