Design And Micromachining Technology Of Surface Bionic Compound Eye Imaging System

As optical technology has found more and more applications,requirements on optical imaging systems become more and more stringent.Single-aperture imaging systems are now unable to meet the needs on applications with requirements on large-field imaging,targeted positioning and detecting due to their limitation on small field of view.Due to the merits of small volume,large field of view and sensitive to fast moving objects,bionic compound eyes have been receiving more and more attentions from researchers for the past few decades.The compound eye consists of a large number of ommatidia which are closely arranged.Since the compound eye can image the target object by a plurality of ommatidia simultaneously and it also possesses a high degree of centralized processing of the neural network,therefore moving objects can be positioned and detected accurately at a large field of view.However,it is found that one of the great challenge on the research of compound eyes is that it is difficult to realize the curved microlens array as well as curved bionic compound eye imaging system based on which due to the traditional planar micromachining technology.To surpass this problem,this paper proposes and develops a novel micromachining technology which is able to fabricate microlens array on curved surface.Based on the fabricated curved microlens array,a bionic curved compound eye imaging system is then designed,prototyped and tested.The main research work includes the following aspects:Firstly,a new soft lithography replication method is proposed which is able to realize the fabrication of curved microlens array on curved substrates.Then the optical imaging experiments were carried out on the fabricated curved microlens array,which is the core device and the base for the design and formation of the curved bionic compound eye imaging system.Secondly,a prototype system of curved bionic compound eye imaging system was built by integrating an optical relay system,the fabricated curved microlens array and the image sensor together.The main function of the optical relay system is the image surface transformation.By designing the optical relay system,the curved focal plane formed by the curved microlens array can be transformed into an planar focal plane to match with the planar surface of the imaging sensor.At the same time,the aberration of the optical system is also corrected by the optical relay system.The optical imaging experiment shows that the formed prototype curved compound eye has a good imaging quality.Finally,to meet the requirements on the large field of view of the capsule endoscope,the optical design of the bionic compound eye imaging system was incorporated and a 100° large field of view was realized for capsule endoscope imaging system.The novel curved microlens array fabrication method and curved bionic compound eye imaging system developed in this paper are expected to have a great potential applications in medical,military,aerospace and other fields.