A Compact Compound-eye Imaging Module Based On Fresnel Microlens Array

With the development of optical imaging systems,its application area is expanding as well.In some specific applications,such as medical detection,intelligent weapon optical guidance,identification,and military target detection,the traditional single-aperture optical system is not meet demand.And hindered by the factors such as diffraction limit,achievements of miniaturization became more and more difficult.It has been found that the insect compound eyes in the biological world have a series of advantages such as miniaturization,wide field of view and sensitive moving objects,therefore,a bionic compound eye imaging system is proposed.Unlike a monocular imaging system such as the human eye,a biological compound eye consists of a number of small eyes arranged in a curved surface,each small eye is equivalent to a single aperture imaging system,and these single aperture systems are combined into a multi-aperture system and simultaneously acquire imaging information,which makes the system miniaturized,lightweight and achieves the purpose of increasing the field of view.It is also one of the future development directions of optical imaging technology.In this paper,we successfully used the maskless gray lithography technology to fabricate Fresnel microlens array devices which can be applied to planar compound eye imaging system.The isolation array layer in the conventional compound eye imaging system is removed by an image reconstruction algorithm,by this way,we reduced the fabrication of the isolation layer and the cumbersome steps of aligning the microlens array with the isolation aperture.The feasibility of the scheme is verified by constructing a compound eye imaging system for human fingerprint recognition experiments.In addition,a compound eye imaging system with a flexible Fresnel microlens array is fabricated using PDMS material,which provides an idea for constructing a variable-focus curved compound eye imaging system.