A Hybrid Index Grating for Finer Installment Tolerance of Exposed-Type Linear Encoder

Abstract

With the development of industrial 4.0, higher accuracy is required for optical linear encoder which serves as an important type of displacement sensor. The mounting error is a great impediment to this quest, especially for exposed-type encoders. This paper presents a novel approach based on the theory of multi-slit diffraction to increase the mounting tolerance. A model of the amplitude-phase grating is designed and simulated on MATLAB and Virtual Lab Fusion. The result shows that the sample encoder is functional when the gap between the reading head and reflective tape is within the 0.35-Imm range, which is superior to previous types of literature study. Furthermore, this design on index grating is economical and without increasing complexity for assembly; therefore, it is applicable for real-life industrial mass production.