Optical Design Of Infrared Target Simulator Based On Telecentric Structure

Infrared target simulator plays an important role in infrared target detection recognition,hardware in the loop simulation and other fields.The hardware in the loop simulation system is composed of scene generator,infrared thermograph,five axis turntable and so on,which can simulate the infrared target and evaluate the detection device performance.The infrared target simulator using the resistor array as the scene generator is most widely used in the present time.However,some infrared target simulator optical systems have the cold reflection of the resistance array in the use of the normal design structure,which seriously affects the system image quality.In order to solve this problem,this paper proposes a design method of infrared target simulator based on image space telecentric system.Firstly,the current situation of infrared target simulator and cold reflection based on resistance array is analyzed,and a new idea is proposed to solve the cold reflection of resistance array by using the structure of the image space telecentric system.Then the system design index is put forward according to the user's request,and the optical system design of two sets of target simulators is completed by Zemax software.Then give the tolerance and judge the image quality.The system entrance pupil diameter is 50 mm,the field angle is ±4 degree,the wave band is 3~5?m,the focal length is 180 mm.The distortion and modulation transfer functions of two optical system meet the design requirements,and the tolerance range meet the processing requirements.After completing the system design,the key component-the resistance array is analyzed,selected and modeled.The structure of infrared thermal imager is analyzed,and the overall system design method based on the maximum efficiency of the cold stop is put forward.On this basis,the cause of the cold reflection problem of the resistor array and the specific process of solving the problem by using the image space telecentric system are analyzed.Then Tracepro software is used to complete the modeling and simulation of the overall cold reflection of the two systems.Compared the results of the two system simulation and calculation,it is proved that the image space telecentric system can solve the practical problems of the cold reflection of the resistance array,and has the application value.Finally,the structure of the lens tube is modeled and the stray radiation is analyzed for the whole system.The calculation method of the glare index and the temperature difference of the image surface used to evaluate the influence of the stray light is given.The integral radiation transmission rate analysis shows the necessity of the lens coating processing.The stray light analysis gives the proportion of the contribution of the stray light of the system structure.The calculation shows that the stray light coefficient and the temperature difference of image surface meet the actual requirements.The ghost image analysis shows that there is no ghost image in the optical system.The stray radiation of the designed system meets the requirement of index.