Patent ID: 6093928
Filing Date: 2000-07-25
Classification: G01D

Abstract:
An incremental encoder comprising:a rotor having a peripherally disposed main scale and a plurality of circumferential indices;a stator having a first subscale disposed for optical communication with said main scale and a second subscale disposed for optical communication with said indices; anda detecting means comprising a light source unit and a light-receiving unit disposed with the rotor and the stator there between;wherein, from a zero reference point on the rotor, the indices are spaced according to a first relationship in a first direction and according to a different second relationship in an opposite second direction,wherein said first relationship and said second relationship are both chosen from the group comprising(a) relationships of consistently increasing interval; and(b) relationships of consistently decreasing interval;and wherein said first relationship and said second relationship are both the same with respect to whether they are consistently increasing or consistently decreasing;but wherein the magnitude of said intervals of said first relationship and said second relationship are not identical.