| 摘要 |
PROBLEM TO BE SOLVED: To provide a rotary encoder capable of suppressing the reduction of detection accuracy caused by retro-reflection light from a non-transparent part of a rotary disk.SOLUTION: In a rotary encoder, each track of a rotary disk 1 has a transparent part and non-transparent part 14 alternately arranged in a circumferential direction. The non-transparent part 14 has a plurality of projections aligned and arranged in a radial direction, and each projection has a pair of reflective surfaces for retro-reflecting incident light toward a light-emitting part 2. The plurality of tracks include a periodic track Ta having the transparent part and the non-transparent part 14 arranged with a periodic pattern and an aperiodic track Tb1 having the transparent part and the non-transparent part 14 arranged with an aperiodic pattern. The periodic track Ta and the aperiodic track Tb1 are respectively arranged at positions in the radial direction without entering light further reflected in the light-emitting portion 2 into the periodic track Ta after being retro-reflected on the reflective surface of the aperiodic track Tb1.SELECTED DRAWING: Figure 4 |
