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:
Sep. 09, 2014
Filed:
Nov. 30, 2011
Takuya Noguchi, Tokyo, JP;
Hajime Nakajima, Tokyo, JP;
Takeshi Musha, Tokyo, JP;
Yoshinao Tatei, Tokyo, JP;
Takashi Hirai, Tokyo, JP;
Takuya Noguchi, Tokyo, JP;
Hajime Nakajima, Tokyo, JP;
Takeshi Musha, Tokyo, JP;
Yoshinao Tatei, Tokyo, JP;
Takashi Hirai, Tokyo, JP;
Mitsubishi Electric Corporation, Tokyo, JP;
Abstract
An optical encoder includes: an optical scale having periodical optical patterns and can be relatively and angularly displaced; a projector for irradiating the optical scale with light; a light receiver for receiving light from the optical scale; and a calculator for calculating an absolute rotation angle θ of the optical scale in accordance with a signal from the light receiver. The optical patterns include a plurality of light shielding portions and a plurality of light transmitting portions, each of the portions being located alternately. When a pitch of an n-th light shielding portion in a predetermined circumferential direction is denoted by Pn and a width of the n-th light shielding portion is denoted by Wn, a transmissivity T(θn) corresponding to an angle θn of the n-th light shielding portion and the pitch Pn of the light shielding portion satisfy predetermined equations, and the width Wn of the light shielding portion in the optical pattern varies in accordance with a function of the pitch Pn of the light shielding portion.