Optics for Encoders and Integration

Abstract

Optics for encoders is studied from the point of view of signal improvement and miniaturization. Basis of optical encoder is the superposition of two gratings. Moire encoder consisting of two superimposed gratings is simple but the encoder signal is often affected by the variation of air gap due to the Fourier image effect. In this paper, basic optics of the encoders is summarized and some advanced optics for the Moire encoders are explained to suppress the influence.