| With the development of new detection technologies,the detection band of the seeker is becoming wider and wider.The conventional infrared dual-band scene projection system is unable to meet the simulation needs.A collimated projection that can work in multiple infrared bands and has good imaging quality has been concerned by researcher.The reflective system has become the focus of the current broad band imaging system research because of the characteristics of no chromatic aberration,wide working band,easy availability of materials,high coefficient of utilization of light energy and simple structure.In this thesis,we study the reflective infrared multi-band projection system,which mainly includes the following contents:Firstly,the technical characteristics and advantages and disadvantages of the reflective projection system are analyzed through making research on the status of the reflective projection system.Combining with the simulation environment of the five-axis flight simulator,a projection system is proposed with large exit pupil distance,large field of view,small volume and weight.The reflective multi-band projection system is based on an off-axis three-mirror system.A plane mirror is established between the secondary mirror and the tertiary mirror to avoid acoustic image and meet engineering requirements.The light emitting surface light source and the infrared detector of the whole system are analyzed,and related parameters are obtained.Secondly,based on geometrical optics and the theory of primary aberration,the calculation method of the initial structure of the coaxial three-mirror system is analyzed.According to technical parameters of the reflective projection system,relevant parameters are calculated and a coaxial three-mirror system is established.Diaphragm off-axis and field off-axis are combined to design the system,and the ZPL macro is edited to further optimize the system volume.The exit pupil diameter is 60 mm.The focal length is 360 mm.The field of view is ±4°.The exit pupil distance is 1300 mm.The working band is 1 to 12 μm.The image quality evaluation and tolerance analysis are performed after finishing the design of system.Finally,the typical lens cone form of the off-axis reflection system is analyzed,and the lens cone of the projection system is selected as an all-metal frame type structure.Based on the structure size of the reflective projection system,the lens cone model is established in Solid Works and maked to stress analysis.After combining the lens cone,reflective projection system and seeker system,stray lightanalysis was performed on the entire system.The stray light analysis mainly includes the calculation of the transmittance of infrared radiation,the analysis of stray light coefficient,the ghost image analysis,and the analysis of the stray light emitted by the system.The analysis results show that the stray light in the system has little influence on the seeker imaging and the design of the reflective projection system meets the requirements. |
PDF Full Text Request