A 22-bit image encoder with optoelectronic integrated chip

Abstract

This study aims to design an optoelectronic integrated chip to read absolute code information. A detector array matching the code disk was designed to better realize high-speed low-light detection. For the pseudo-random code channel, the readout circuit adopted a linear array CMOS image sensor architecture, where each pixel corresponded to an independent readout unit, making the readout signal more advantageous in terms of both reading speed and noise. For the incremental code channel, the readout circuit followed a distributed arrangement design, and a two-stage pipelined amplifier architecture was adopted to eliminate the influence of even harmonics and ensure the quality of the read signal. Finally, a high-precision angular displacement sensor test platform based on an optical continuous closed-loop was built to test the encoder prototype equipped with the chip. The results show that an angular resolution of 22 bits and a subdivision accuracy of 5.64″ have been achieved.