Infrared Telescope Automatic Temperature Compensation Technology Research

Most of optical instruments, especially for military application, are required to operate in a wide ambient temperature range. As temperature changes, the curvature and thickness of optical parts as well as the distance between optical parts will change, the refractive index of the material and the refractive index of the transmission media also follow the change. Meanwhile, the body of the instrument expands or contracts with varying temperature, which causes imaging plane shifting from the focus. Therefore, the system performance is degraded. Because refractive index temperature coefficient dn/dT of the infrared material is one order larger than that of the visible material, the imaging plane drift in transmission infrared optical system is also one order larger that that of the latter one. Ambient temperature imposes a significant impact on infrared optical system. In order to ensure infrared optical system to operate properly in wide temperature dynamic range, an active or passive compensation mechanism is introduced in infrared imaging system to compensate the system performance degradation caused by imaging plane drift resulted from temperature variations.The paper analyses the effect of the environment temperature on the infrared optics system. The temperature auto-compensation technology for infrared telescope is investigated thinking about the factual engineering task. The paper gives out the designed circuits of temperature measuration and temperature auto-compensation. The software flowchart for infrared telescope temperature auto-compensation is given as well. Debugging the circuits is done at last and gets the experiment result.The investigation and experiment indicate that the designed circuits can well do the temperature auto-compensation for the imaging plane drifting of the infrared telescope, which bases on mechanical-electrical initiative compensating principle.