Design Of Off-axis Reflecting Collimator With 350mm Aperture

In combination with the research topic of "self-propelled XX dynamic test simulation target",this paper designed an off-axis three-mirror collimator with large diameter and long focal length,and combined with DMD(digital micromirror device)target generator,which can provide static and dynamic simulation target for the calibration of measured optoelectronic equipment carried by large armored vehicles.It is mainly used in static and dynamic simulation of objects at a certain distance or infinity.When designing the optical system,the influence of stray light on the imaging quality is taken into account.When stray light enters the optical system,the image contrast and SNR of the system will be reduced.Considering the actual situation,there is a distance of more than 10 m between the detected equipment and the simulation equipment,so the detected photoelectric equipment cannot detect the simulation target when the stray light is serious.Therefore,the design of the stray light suppression mechanism is an essential and important link.In addition,in the installation and adjustment of the optical system,we need to consider not only reducing the difficulty of installation and adjustment,but also ensuring the installation and adjustment accuracy within the allowable range of the design.Based on the above considerations,this paper carries out theoretical research on off-axis three-mirror optical system,optical system design and mechanical structure design,stray light suppression structure design and computer simulation aided installation and adjustment research.Mainly completing the following research works:(1)Design of collimator optical system.By comparing the structures of various optical systems and combining the requirements of large field of view,long focal length and compact structure,the off-axis three-mirror optical system was selected to carry out the research.According to the subject index,the relevant parameters of the optical system were calculated,and an off-axis three-mirror optical system with an entrance pupil diameter of 350 mm,a focal length of 2800 mm and a full field of view of 2° was designed by using the software.image quality evaluation and tolerance analysis were carried out for the optical system,and reasonable tolerance allocation results were obtained.(2)Structure design of collimator optical machine.On the basis of optical design,the mechanical structure is designed,combined with structural design software,the shape changes of the primary mirror and the primary mirror components under the action of gravity are analyzed by finite element method,and then using MATLAB to analyze the deformation data,calculate the PV value of surface shape change and RMS values.In addition,the parametric design and optimization of the primary mirror is carried out,and the related structural parameters of the fixed hole of the primary mirror are improved,so that the surface shape variables are reduced under their own gravity.primary(3)Stray light analysis and suppression structure design of the system.In this paper,the sources of stray light,the mechanism of energy transfer,the analysis methods and evaluation indexes of the inhibition performance are introduced in detail.The position of the blocking ring of contour type and gradient type is determined by the combination of geometric drawing and computer programming.Based on the optical system in this paper,two suitable models of stray light suppression structure are designed,namely,conical contour hood and cylindrical gradient hood.(4)Computer aided installation and adjustment technology.The sensitivity matrix method and reverse optimization method are used to simulate the optical system in this paper.Through MZDDE software package,MATLAB and ZEMAX software are related to simulate the effect of the imbalance amount in the process of loading and adjusting on the image quality of the system.At the same time,comparing the results of each kind of analog modulation with the results of design results,and it has certain guiding significance to the actual modulation of optical system.