【作者】 乔杨；

【导师】 徐熙平；

【作者基本信息】 长春理工大学 ， 仪器科学与技术， 2013， 博士

【摘要】 红外制导导弹以其探测手段的隐蔽性及抗干扰能力强等优点不断受到人们的重视,随着成像制导导弹的不断发展,红外目标模拟器作为测试与评估导引头的有效手段亦随之不断更新。红外光学引擎是红外目标模拟器的重要组成部分,其设计的合理性直接影响整个系统成像的照度均匀性、对比度、分辨率等因素。本文通过分析对比各景象生成器件的性能,最终选用DMD(Digital Micro mirror Devices)作为景象生成器件,并设计了一套双视场红外目标模拟器的光学引擎。文中分析了基于DMD光学引擎的结构特点及设计难点,详细讨论了光学系统中使用的远心光路结构的组成部分,及各组份之间的关系。由于红外目标模拟器光学引擎是一个集光、机、电、算一体化的技术,对于光学引擎的设计要同时考虑到光源与照明光学系统的光瞳匹配,照明光学系统经TIR(全内反射,Totally Internally Reflect)棱镜入射到DMD上的入射角与DMD偏角之间的关系。为实现在DMD微反射镜“开”状态时所有入射光都能入射到投影系统光瞳处,且“关”状态和“平”状态所有入射光都不能进入到投影系统光瞳,在设计TIR棱镜时要特别计算棱镜各参数的量值。此外为使红外目标模拟器与导引头相匹配,在设计投影光学系统时要考虑到导引头的技术参数,同时还应满足投影系统的入瞳与照明光学系统的出瞳相匹配。文中以某双视场导引头为例,设计了一套与之匹配的红外光学引擎。由于选用远心光路结构,设计过程中可以将照明光学系统与投影光学系统分开单独设计。首先对照明光学系统进行设计。通过分析光源、DMD等技术参数,利用光学扩展量,确定照明光学系统的结构为临界照明,并拟定照明光学系统的设计参数。此外根据TIR棱镜的特点及其在照明光学系统所中起的作用,综合考虑照明光束入射角度与DMD偏转角度之间的关系,满足在DMD微反射镜“关”状态时没有光线入射到投影光学系统中,以此确定TIR棱镜的各项参数。对设计参数分析完成后,进行了照明光学系统设计。并利用Light Tools软件分析照明光学系统的照明均匀性等技术指标。分析结果表明,照明光学系统基本满足设计要求,像面均匀性良好。然后对双视场投影光学系统进行设计。由于投影光学系统要与某双视场导引头相匹配,故在确定投影光学系统的设计参数前首先讨论了双视场导引头的技术参数。同时,为保证照明光学系统与投影光学系统匹配,应满足拉赫不变量相等,据此确定投影光学系统的设计参数。通过对MTF,弥散斑,畸变等分析,表明投影光学系统设计满足成像要求。文中对投影光学系统的公差进行了分析,保证了投影光学系统的倾斜、偏心、厚度等参数在满足公差要求较为宽松的同时,双视场投影光学系统仍可以清晰成像,达到设计要求。最后文中对整个光学引擎的结构及光学性能进行了分析,讨论了仿真温度与黑体工作温度之间的函数关系,并计算了整个结构的能量损耗系数。最后得出,本红外目标模拟器光学引擎设计合理,与双视场导引头匹配,实现双视场目标模拟功能。更多还原

【Abstract】 Due to the advantage of difficult to discover and strong anti-interference, people have paid more and more attention to infrared guided missile. With the development of infrared imaging guidance missile, infrared scene projector (IRSP) as the most effective method to evaluate the seeker’s performance has made great progress. Infrared optical engine is one of the most important parts of IRSP. The design of the IR optical engine directly affects the performance of the whole system, including illumination uniformity, contrast ratio, resolution and so on.In this dissertation, a duel field optical engine of IRSP is designed. Compared with the performance of numbers of IRSP technologies, DMD is chosen as the scene generator.This dissertation has analyzed the structure characteristic and design difficulties of optical engine based on DMD. In this dissertation, the component of telecentric structure used in DMD optical engine has been discussed. And the relationship between each component has also been analyzed. The optical engine of IRSP is an integration technology which associated with optic, mechanic, electron and compute. During the design of the optical engine, some problems need to be considered. First of all, the pupil of the illumination optical system should be matched with the light source. Secondly, the relationship of the incident angle and reflected angle for the chief ray of incident light bundle on each mirror of DMD should be considered. Thirdly, in order to ensure that all of the rays that transmitted by the illumination optical system should be guided to the pupil of the projection optical system when the mirrors of DMD is on state, and are prevented to enter the pupil when the mirrors is off state, the parameters of TIR prism requires precisely computation. Last but not the least; the IRSP should be matched with the seeker. Because of this, during the projection optical design, the seeker’s parameters should be considered. Meanwhile, the projection pupil should be matched with the illumination optical system.This dissertation has taken one duel-field seeker as an example, and designed one optical engine of IRSP for the seeker. Because of the structure chosen in this dissertation is telecentric structure, the light path of the projection and illumination optical system (for prism design) can be designed independently.First of all, the illumination optical system has been designed. By analysis of the light source, DMD and other technical parameters, the etendue was first calculated. Then we have analyzed the light source and the technical specifications of DMD and chosen critical illumination as the illumination mode. Finally the design specifications for the illumination optical systems have also been determined. In addition, in order to compute the parameters of TIR prism, some problems need to be considered. Based upon the characteristic of TIR prism used in illumination optical system, the relation between illumination angle and the mirror-tilt angle of DMD should be considered first. Secondly it is also necessary to make sure that the whole light of off state could not enter the projection optical system. After the analysis of all the technical parameters, the TIR prism system has been designed. The illumination uniformity of the illumination optical system is evaluated by Light Tools. The analysis results showed that the illumination system designed in this dissertation meets the design requirements. The illumination uniformity is good and the system could modulate the light reflection of DMD.One duel-field projection optical system has been designed. Because of the projection system should be matched with the duel-field seeker, the technical parameter of the seeker has been discussed before the design of the whole IRSP optical system. Meanwhile, in order to ensure that the illumination optical system is matched with the projection optical system, the projection optical system has been designed with the consideration that the Lagrange Invariant of the illumination and projection optical system should be equal. The MTF, spot radius and distortion have been analyzed to evaluate the projection optical system. The results have shown that the projection optical system met the design requirements. Finally, he tolerance of the projection optical system has been discussed. Analysis have shown that with relatively loose tolerances of tilt, decenter, thickness etc., this duel field projection optical system could still have a good imaging quality, which means that the optical design is fairly good.At the last part of the letter, the structure of the whole optical engine and its optical performances has been analyzed. The relation between simulating temperature and the working temperature of the illumination blackbody was also discussed. The energy loss coefficient of the whole optical engine has been computed. Finally, it has been shown that the optical engine of IRSP designed in this dissertation is designed rationally, and it is matched with the duel field seeker. It could achieve the function of duel field simulation.更多还原