Patent ID: 7105803

Claim:
A rotary optical encoder for outputting phase-changing signals in a permanently magnetized motor comprising a rotating axis and a rotor fixed thereon, the rotary optical encoder including: a code wheel, which is coupled to the rotating axis and has a code track with a plurality of regions, each of which has a first non-transparent part, a first opening, a second opening, a third opening, a fourth opening, and a second non-transparent part, wherein the first non-transparent part, the first opening, and the second opening are symmetric to the second non-transparent part, the fourth opening, and the third opening respectively, the first opening and the fourth opening are one-unit openings, and the second opening and the third opening are two-unit openings; a light emitter, which projects a beam of light on the code wheel; two light sensors, which is located one side of the code wheel opposite to the light emitter for detecting the light intensity through the code wheel; and a processing circuit, which is connected to the light sensors to convert the light intensity into a phase-changing signal for output.