Design and analysis of an optical zoom system-based on super-elastic film liquid lens

As a new type of zoom element, the liquid lens has the characteristics of fast response, no wear, and small size, which brings new ideas to the design of the zoom system. This paper proposes a liquid-solid composite zoom optical system without mechanical movement. In the system, two liquid lenses are used as the zoom group and the compensation group of the system, so that the image plane position is always stable during the zooming process of the system. Based on the Gaussian theory, the relationship between the focal length of the system and the focal length of a single liquid lens is derived, and a multi-layer traversal algorithm is proposed to solve the initial structure parameters of the system. The optimized design of the zoom optical system and image quality analysis was completed by using ZEMAX software. The results show that the system can achieve continuous zoom in the range of 20-60mm, the zoom ratio of the system is 3, and the image quality is good. The modulation transfer function of each focal length of the zoom system at a spatial frequency of 50lp/mm is greater than 0.2, and the RMS value of wave aberration is greater than 0.3 times the wavelength of the probe light, which meets the design requirements.