The Design Of Mechanical Passive Athermal Infrared Lens Based On The Structure-Thermal-Optical Integrated Analysis

With the development of integrated manufacturing industry,people make higher requirements for the design of the infrared lens.When the mechanical passive athermal infrared lens comes to designing,the relationship among refractive index of the optical element,lens interval,lens center thickness and temperature variation should be fully considered.Therefore,in order to ensure the rationality of the design of the mechanical passive athermal infrared lens and get the common optical performance of the lens,we need to design it by the method of structure thermal optical integrated analysis.This research is based on the basis of the design theory of mechanical passive athermal infrared lens to analyse thermal deformation displacement with regards to three kinds of thermal compensation materials by ANSYS's structural analysis module.POM,which was relatively stable in the process of thermal expansion and had a better simulation,was chosen as a kind of compensation material According to the Pro-e structure design module,the structure of mechanical passive athermal infrared lens has been designed.With the purpose of verifying whether the mechanical passive athermal infrared lens was designed to meet the operating requirement,the method of structure thermal optical integrated analysis should be taken.In ANSYS,the finite element model of the infrared lens was established.In order to get the equivalent displacement data and thermal stress data of the lens,the highest and lowest temperature in the normal temperature range of infrared lens were selected as a loading applied to the infrared lens to do the thermal stress analysis.According to the results of finite element analysis,whether the theoretical compensation quantity of lens meets the requirement and the deformation of lens at high and low temperature could be judged.Then,through the separation of rigid body displacement and fitting of mirror surface shape,the relevant data can be added into the Zemax for optical performance,thus,imaging quality of the lens at high or low temperature can be obtained.The analysis results indicate that the optical performance of the athermal infrared lens was the best when at 20 ?.No matter at high or fow temperature,the image quality are both reduced to a certain extent,the decline was more obvious at low temperature.In general,the optical performance of the lens can meet the operating requirements.At the end of this research,the model of the infrared lens we designed have had the high and low temperature experiments as well as the MTF test.The results shows that the design method of structure thermal optical integrated analysis is feasible.In addition,the structure thermal optical analysis results approximately agree with the experimental results.Therefore,the design of mechanical passive athermal infrared lens based on the structure thermal optical integrated analysis could be used in engineering practice,which has a certain guiding significance for optomechanical integrated design of infrared lens as well.