针对红外搜索及跟踪系统中折反式光学系统结构复杂，装调困难及成本高的问题，采用了一种一体式折反结构的透镜。在单片透镜的前后表面进行分区域加工，分别镀上内反射膜和增透膜，形成两个反射面和两个透射面，构成折反一体式透镜。将整个光学系统集成在一片透镜上，降低了系统的复杂度和装调难度，提高了系统的稳定性和可靠性。设计了适用于中波红外的紧凑型成像光学系统，远射比达0.62，结果表明该系统像质优良；各视场光学传递函数均大于0.55，接近衍射极限，并且利用二元衍射光学元件在-40 ℃~60 ℃实现光学被动消热差；最后利用单点金刚石车床加工出的样机在不同温度下进行成像实验，结果表明在不离焦的情况下，各温度下成像清晰，满足实际加工和应用需求。

In order to solve the problems when the R-C reflect IR system and the stability of the second mirror is installed, a compact integer structure is presented. The front and rear surface of lens are machined. Then inner reflect films are coated on two surfaces. At last the two mirrors are assembled in one lens which makes the installation of the two mirrors easier and the structure of the second mirror more stable. Reflection and antireflection films are coated on different surfaces respectively. Then two reflective surfaces and two transmission surfaces are produced on single lens. The entire optical system is integrated on a lens. It can not only effectively reduce system complexity and the difficulty of alignment, but also improve the stability and reliability of the system. A design of medium wave infrared (MWIR) compact optical system is presented. It has good imaging capability with modulation transfer function (MTF) of all field of view more than 0.55 which is very close to the diffraction limitation. The optics system realizes athermal between -40 ℃~60 ℃by binary diffractive optical element. Finally a real lens is manufactured by a single point diamond turning machine and imaging experiments is carried out at different temperatures. The results show that the optical system performance well without defocus. The system meets the actual processing and application requirements.