Research On The Optical Coupling Technology Of Infrared Target Simulator

Hardware in the loop simulation system is mainly used to test the tracking ability of the seeker, by using indoor simulation method instead of outdoor field experiment. Infrared target / jar imaging simulator is an important component of hardware in the loop simulation system. With the development of technology about missile, the type of infrared simulation system has also undergone a corresponding change. Now, the infrared target simulator should not only simulate the characteristics of targets, but also should simulate the characteristics of many disturbances. These disturbances are often generated by using an independent optical method, furthermore each independent source is ultimately compound to provide to the seeker to receive. All the decoys and objectives that are simulated should enter and fill the entrance pupil. That involves the technology of the coupling and expanding of multiple beams. According to the general design, because of the low temperature of resistance matrix, it is necessary to reduce the transmission rate of optical interference to ensure the energy of objectives. And the compound projection methods produce another new problem: there are two stops in the light path, leading to the aperture of the follow-up optical system can not be filled with the beam of the front optical system. Therefore, in order to ensure the authenticity of seeker tracking targets, it is necessary to couple the multiple beams and expand beams to fill the aperture of follow-up optical system. Optical coupling technology of infrared target simulator has been research in this paper. The author also analyzes the various factors on the coupling effect and the impact of energy utilization. The main contents include the following three parts.(1) Elements of infrared target / jar imaging simulator have been introduced in this paper. The key technology is turn the multiple fine-beams coupled and expanded to a broad-beam, and then provide to the seeker to receive. The author lists many coupling beam expander device that netted mirror, optical fiber cable, light scattering devices, and microlens array. Their principles of coupling and expanding beams have been analyzed in this paper. According to dimensions of infrared target simulator, simulation accuracy and requirements of energy utilization of coupling and expanding system, the microlens array will be used as infrared target / jar simulator coupling element.(2) The author also studies the distribution and energy utilization when the beam of light through the microlens. The coupling beam model is used to design micro-lens. Microlens aperture ( D ? 20μm), and focal length ( f微' ?28μm) are initially identified. Then the parameters of microlens and field lens have been put into the optical design software. In accordance with the requirements for the maximum of energy utilization of coupling system, this article optimizes parameters of the microlens. The results are: the microlens aperture is D ? 20μm, and the focal length is f微' ?37μm. Which makes the energy utilization of the center field is ? =0.73 and the energy utilization of the edge field are ? =0.488 and ? =0.171, which are all met the requirements (? >0.15). This article also analyzes the microlens radius, the substrate thickness and the processing error of substrate thickness, environmental temperature, and the different microlens position of light spot falls on the influence of the energy utilization, ensures that the above factors on errors of energy utilization are less than 0.1.(3) Existed mature technology for the domestic, this paper uses melting photoresist to make microlens. The author calculates the parameters of microlens when the photoresist processing, then analyzes the accuracy of these two effects that the photoresist thickness in the adhesive process and height of spherical in the etching process. Finally, the necessary microlens processing parameters and processing errors on the system energy utilization have been discussed in this paper.By studying, this paper proofs that the microlens as the optical coupling device of infrared target simulator is feasible in principle and in processing technology. The results can be used for energy distribution of microlens array of the follow-up works.