ROTARY ENCODER

摘要

In a rotary encoder of the present invention, each track of a rotary disk has transmitting parts and non-transmitting parts alternately arranged in the circumferential direction. Each non-transmitting part has a plurality of projecting parts which are arranged side by side in the circumferential direction. Each projecting part has a pair of reflecting surfaces which retro reflect incident light toward a light emitting part. A plurality of tracks include a periodic track where transmitting parts and non-transmitting parts are arranged with a periodic pattern and non-periodic tracks where transmitting parts and non-transmitting parts are arranged in a non-periodic pattern. The periodic track and non-periodic track are respectively arranged at positions in the radial direction. where further reflected light at the light emitting part after retro reflection at the reflecting surfaces of the non-periodic track will not enter the periodic track.

主权项

1. A rotary encoder comprising
a rotary disk which has a rotation axis, and a light emitting part which emits light toward said rotary disk, wherein said rotary disk has a plurality of tracks which extend concentrically about said rotation axis, each of said plurality of tracks has light transmitting parts which transmit incident light to said rotary disk and non-transmitting parts which do not transmit incident light to said rotary disk, said light transmitting parts and said non-transmitting parts being arranged alternately in a circumferential direction about said rotation axis, said non-transmitting parts have pluralities of projecting parts which are arranged along said circumferential direction of said rotary disk, each of said plurality of projecting parts having a pair of reflecting surfaces which retro reflect incident light to said rotary disk toward said light emitting part, said plurality of tracks include a periodic track where said light transmitting parts and said non-transmitting parts are arranged in said circumferential direction with a periodic pattern and a non-periodic track where said light transmitting parts and said non-transmitting parts are arranged in said circumferential direction with a non-periodic pattern, and said periodic track and said non-periodic track are arranged in a radial direction of said rotary disk at positions where further reflected light at said light emitting part after retro reflection at said reflecting surfaces of said non-periodic track will not enter said periodic track.