Patent ID: 7405393
Filing Date: 2008-07-29
Classification: B41J,G01D

Abstract:
1. An optical encoder comprising: an optical grating for modulating a beam of light; a sensor for sensing modulated light provided by the optical grating; the optical grating and the sensor being movable relative to each other; and the optical grating including an optical track comprising a series of contiguously adjacent encoder bars that are substantially uniformly spaced center to center so as to have a substantially uniform pitch, the series of contiguously adjacent encoder bars including (a) a plurality of contiguously adjacent first encoder bars and (b) a plurality of second encoder bars, wherein the contiguously adjacent first encoder bars and the second encoder bars have non-linear sides, wherein a first non-linear side of the first encoder bar has substantially the same shape as a first non-linear side of the second encoder bar and a second non-linear side of the first encoder bar has substantially the same shape as a second non-linear side of the second encoder bar, and wherein each of the first encoder bars has a width that is different from the substantially constant second encoder bar width.