Novel system for optical axis on-line calibration

Abstract

Calibration of optical axis is an essential process to ensure the quality of optical systems. Only when the light path center, CCD (Charge Coupled Device) center and rotary center of motor fit each other well, can the system run properly to fulfill the proposed function. However, in most cases, the process is conducted by experienced workers and it is hard to precisely evaluate the coherence of optical axis. So the development of an optical calibrator that can detect the optical axis and calibrate the center automatically is of high priority for precise optical instruments. In this research project, we aim to develop a novel system for optical axis online calibration. The system is based on photoelectric encoder for rotary signal sampling of motor. MCU (Micro Controlling Unit) is used as the main control module instead of PC to miniaturize and simplify the system. CPLD (Complex Programmable Logic Device) is employed to realize high speed data storage and processing. A motor driving circuit and a voltage interval location method are designed to control the motor to rotate precisely. The novel optical calibrator has already been taken into practical application in factories, and proved to be of high stability and resolution.