基于 Alvarez 透镜的紧凑型红外连续变倍系统设计

In this study, a transverse moving infrared optical continuous zoom system based on the Alvarez lens is proposed to address the challenges associated with the complex structure and large volume of traditional axial-moving mechanical optical zoom systems. The system consists of two sets of Alvarez lenses, apertures, focusing lenses, and infrared detectors. Herein, two sets of Alvarez lenses adopt a Kepler-type telescope structure, where the first set of Alvarez lenses functions as the zoom group and the second set of Alvarez lenses serves as the compensation group. The infinitely far incident light passes through two sets of Alvarez lenses and exits, the emitted parallel light is then focused and imaged onto the target surface of the infrared detector through a fixed focal lens. Utilizing Zemax software for optical simulation, our designed optical zoom system covers the 8?12 μm long wave infrared band, with a maximum field of view angle of 6°, a maximum pupil diameter of 6 mm, an F-number of 2, distortion of <2.1%, and a total optical length of ~74 mm. The Alvarez lens only requires to be horizontally moved by ~1 mm to achieve continuous optical magnification from 5× to 15×. Moreover, the modulation transfer function of the proposed optical zoom system can attain up to 0.5@17 lp/mm, assuming a resolution of 320×240 and pixel sizes of 30 μm for the infrared detector. The simulation results indicate that the system has the advantages of high magnification, a compact structure, and high imaging quality, making it a promising candidate for applications in the field of miniaturized infrared zoom imaging.