Infrared target simulator can simulate the real target and background infrared imaging in the laboratory, offer the exactly controlled and repeated condition for the testing and evaluation to the performance of the infrared detection equipment, testing each performance index during the development phase. The characteristics of the infrared optical systems were analyzed. The system parameters which worked at long wave with 1024 ×768 DMD were given. An optical system of medium-frequency wave dynamic infrared scene projector based on the digital micromirror device (DMD) was given by using secondary imaging. The optical system was designed with a long distance of exit pupil, large working distance and short focal length .The exit pupil distance of the system could reach 740 mm, the entrance pupil aperture is 26.5 mm, and the field angle is 12°x9°. In order to get better resolution and image quality, an optimization result and the system aberration were obtained by the ZEMAX software. The whole optical system using the materials of Ge and Si consisted of 6 elements. It was designed with a refractive hybrid system to reduce color aberration and thermal aberration in the temperature range of 10-40¬°. The projector optical system takes advantage of high quality image with MTF better than 0.6 at a spatial frequency of 16 lp/mm in the full field of view, and the distortion is better than 0.5% which is operational within the working temperature.
Infrared scene simulator is now widely used to simulate infrared scene practicality in the laboratory, which can greatly reduce the research cost of the optical electrical system and offer economical experiment environment. With the advantage of large dynamic range and high spatial resolution, dynamic infrared projection technology, which is the key part of the infrared scene simulator, based on digital micro-mirror device (DMD) has been rapidly developed and widely applied in recent years. In this paper, the principle of the digital micro-mirror device is briefly introduced and the characteristics of the DLP (Digital Light Procession) system based on digital micromirror device (DMD) are analyzed. The projection system worked at 8~12μm with 1024×768 pixel DMD is designed by ZEMAX. The MTF curve is close to the diffraction limited curve and the radius of the spot diagram is smaller than that of the airy disk. The result indicates that the system meets the design requirements.