http://www.usa.canon.com/cusa/semiconductor/products/encoder_optolectronic_components/laser_rotary_encoder/r_1so_r_1sl_r_1p32?pageKeyCode=writeReviewPage
R-1SO, R-1SL, R-1P32
Overview
Canon R-1 series Laser Rotary Encoders offer high performance (high resolution, accuracy, & precision) in a very compact 36mm diameter body. All models utilize semiconductor laser diode, high precision grating disk, and diffraction & intereference position sensing methodology.