Aspheric single-element lens using birefringent material for miniaturized imaging system

Abstract

An aspheric single-element lens made of birefringent material is proposed in this paper. This lens is capable of suppressing aliasing artifacts in a captured image, which is caused by inability of the image sensor to detect fine patterns with higher spatial frequency than the Nyquist frequency of the sensor array. At the same time, this lens possesses converging capability like a conventional convex lens and tolerable optical aberrations by employing aspheric surfaces. Compared to conventional imaging systems that use multi-lens structure to tackle optical aberrations and realize aliasing suppression by stacking up more than two optical low pass filters (OLPFs), an imaging system using our lens can greatly reduce the lens stack height and manufacturing cost. Image capturing simulation using the proposed lens indicates that aliasing artifacts are effectively reduced. This lens is expected to be used in miniaturized imaging system such as smartphone cameras and laptop cameras.