抄録
In this paper, a compact absolute optical linear encoder is proposed. The index scale of the proposed encoder has the two track (80μm and 2mm pitches), which consist of the pitch-modulated grating and slit-width-modulated grating, respectively. Using the modulated gratings, the harmonic noises of the encoder signals are decreased. Moreover, the respective lines of the slit-width-modulated grating are divided and re-distributed in the index scale to suppress the sensing error due to the contamination on the scale. By fabricating the index scale with silicon photodiode arrays, the proposed advantages are confirmed experimentally.
