The resolution and precision of an optical encoder are determined by three factors: (1) the distance between the photodetector and the slit disk, (2) the ratio of the width of the active area of the photodetector to the width of the slit of the slit disk, and (3) the concentricity of the photodetector and the slit disk. A quantitative analysis of these factors generally requires a grasp of sophisticated analytical techniques, including an incoherent spectrum, the optical system of the light emitting diode (LED), and diffraction. We propose a breadboard system and techniques for obtaining the same output signal as that of the actual encoder using the image data of the light intensity as it permeates the slit disk of the encoder, without the aid of the advanced analytical techniques generally required. We then compare the analytical result obtained with this technique with the output signal from the actual encoder to confirm the validity of this breadboard system and technique.
"Breadboard system and techniques to optimize the optical system of an encoder," Optical Engineering 40(2), (1 February 2001). https://doi.org/10.1117/1.1336526