Miniaturized lens design based on free-form surface for micro intelligent instrument

With the development of miniaturization of smart devices, smart device imaging systems require lenses wit h extremely small size, optimal imaging quality and developability. The difficulty in the design of a small lens is how to design a lens with a longer focal length within the limit of the shorter total system length. The design should fit the optimal spatial resolution of the object while ensuring the maximum field of view, and on this basis, avoid large vision distortion caused by the field and other off-axis images. In this paper, a small lens for smart devices with a field of view of 68 degrees and a total length of less than 5mm based on actual engineering is designed and the influence of lens length and lens focal length is analyzed. According to the needs of use, a design method combining spherical, aspheric and free-form surfaces is adopted. The spherical surface is made of glass, and the aspheric and free-form surfaces are molded by plastics, realizing a small lens design with processing feasibility and low cost. The lens will be combined with a focusing module and correction algorithm to be applied to micro intelligent instrument.