Method and apparatus for automatic modulation of photo-emitter brightness in an optical encoder

摘要

A code strip, an optical encoder using such a strip and a method thereof are described. The code strip includes a calibration area. Light transmitted from a light source through the calibration area on the code strip is converted into an electrical calibration signal. This signal is a function of the transparency of the calibration area. The brightness of the light source is automatically modulated to compensate for degradation of transparency of the calibration area.