Research of aberration control in human-eye inspired vari-focal liquid lens

Abstract

In the case of an optical system using a solid lens, mechanical movement is required to vary the focus because it is focused only at a specific distance, and there are physical distance restriction when applied to various application. Liquid lens have the merit of changing the focal length because they can change the shape of the lens freely unlike the solid lens with fixed shape. But commercially available liquid lenses are basically aberrated compared to solid lens. Some attempts have been made to correct the aberration at a specific focal length by making the surface membrane of the liquid lens into a lens shape, but the aberration varies even if the focal length changes slightly. This paper proposes a system that pull the lens surface membrane vertically and horizontally by getting ideas from the lens and ciliary body of the human eye. As the ciliary body of the eye contracts and relaxes to adjust the thickness of the lens, the thickness of the lens surface film can be continuously changed while attracting the lens surface film. This allows control of aberration caused by changes in the focal length of the focus variable lens. In the proposed system, the hydraulic method is used to change the focal length of the lens. The surface of the lens is made of elastic material. Depending on the specific shape, the thickness of the lens surface can be changed and the aberration controlled.