A microlens array (MLA) is a fundamental optical element, which has been widely applied in the fields of imaging sensing, 3D display, and lighting source. However, it is still a challenge to design the MLAs simultaneously satisfying small size, wide field of view, and high image quality. Herein, a novel type of concave lens array on an aspheric convex substrate (CLAACs) is presented, which is composed of an aspheric substrate and a spherical concave subeye array. The facilely designed method of the CLAACs is described and its geometric model is also established by a numerical example. Furthermore, a fabrication method, which is directly machining the CLAACs on PMMA material, is proposed. To realize the ultra-precision machining of the lens, tool path planning is carried out before fabricating. The profile, surface quality, and imaging performance of the fabricated lens are then characterized to reveal its optical capabilities. The results show that the proposed method can realize the rapid design and fabrication of lenses flexibly and efficiently. The fabricated CLAACs exhibit excellent morphology uniformity, high imaging quality, and focusing performance. The study provides a feasible solution for the design and fabrication of such lens arrays with complex discontinuous surfaces.

This paper presents the design and fabrication of a novel double-sided aspherical Fresnel (DSAF) lens on a curved substrate to tackle the Fresnel lens problems such as long focal length and large volume. This novel lens contains a curved substrate and a bifacial aspherical Fresnel lens. The structural design and nonlinear optimization method of the lens were discussed. Then, the optical characteristics of the DSAF lens were also analyzed by Ray-tracing simulations. Furthermore, to manufacture the DSAF lens, considering the machining accuracy and cost-effectiveness, a combined method of single-point diamond turning (SPDT) and press molding was proposed for generating the DSAF lens with PMMA material. Machining accuracy was used to validate the performance of the molds before production of the DSAF lens, followed by testing of the fabricated DSAF lens. The results show that the DSAF lens has the advantages of more design degree, short focal length, small volume, and good light-gathering, etc. which is suitable for mass production. The study provides a cost-effective method for the design and preparation of ultrathin Fresnel lenses.