Research Of Opto-Mechanical Thermal Compensation For Infrared Zoom Optical System

When optical instruments are used outdoors,the working temperature of the system changes in a wide range.The change of working temperature will have an great impact on system performance.For an infrared optical system,defocus will emerge when the working temperature changes, the optical performance will decrease.So it is necessary to compensate the change caused by the temperature variance, which is called thermal compensation.In this paper the current zoom optical system has been analyzed, and the necessity to make the thermal compensation on the system has been proposed. Several kinds of thermal compensation methods are analyzed,mechanical passive and electromechanical active thermal compensation methods are used. Mechanical passive compensation can’t satisfy the requirements,and the electromechanical active compensation is reasonable.Based on the principle of electromechanical active method, the focusing mechanism has been adopted to realize the thermal compensation of IR zoom optical system,and the focusing structure has been designed.The thermal compensation method has been simulated, and the result show that the compensation effect is favorable.Mechanical structure are designed for the optical system and alignment program are proposed.