Study On Imaging System Of Curved Surface Biomimetic Compound Eye

Nowadays, optical imaging system has been applied more and more widely, and its improvements are required, such as light weight, small size of the whole system, large field of the view and more sensitivity to the moving target. With the development of detectors and computer science, single-aperture optical system is unsatisfactory in automation, image recognition, military target diction and other areas. And hindered by the factors such as diffraction limit, achievements of miniaturization become more and more difficult. Enlightened by the virtue of the insect compound eye, such as small volume, large field of view, sensitivity of high-speed moving objects and etc, researchers proposed biomimetic compound eye imaging system. In fact, the proposal of biomimetic compound eye means that the multi-aperture optical system replace the current widespread single-aperture optical system realizing the miniaturization, lightweight and the larger field of view of the system.In this paper, drosophila’s compound eyes were duplicated by using soft lithography technology successfully. Then the imaging system of curved surface biomimetic compound was designed, and the image of the curved surface was transferred onto a plane through an image-plane transition system.Optical detection of the duplicated compound eyes was carried out. From the PSF, we got that the size of airy spot is about2um. the NA of the ommatidium deduced from diffraction theory is approximate to0.36, which touch the critical value of0.3in nature. The result of the imaging of strip grating through the compound eye indicated that the height of an ommatidium could be6.78um, which is agreement with the measured result of5-7um. In this case, the NA of the ommatidium is0.56, which is almost twice as much as0.298. The difference is caused by micro-nano optics properties.To eliminate the difference affected by detector defocus for different view field angle, the imaging system of curved surface biomimetic compound adopts design of telecentric beam path, in which outgoing rays at different view field are perpendicular to image plane.At601p/mm, the average MTF off axis is higher than0.5, while the average MTF on axis is higher than0.6. This demonstrates that high imaging quality was observed both on axis and off axis. Field curvature and chromatic dispersion are all corrected perfectly, and the distortion of the lens is approximate to1%. Moreover, with the telecentric structure, the illumination uniformity was improved, and the illumination hardly changed with view field.The main contents of the paper are as followed:Chapter1, introduction of the biomimetic compound eye. We propose the background and significance of the study on biomimetic compound eye, summarize the current development of the biomimetic compound eye imaging system, and point out the main existing problems of the study.Chapter2, introduction of detailed physiological structure of the compound eye, the specific classification of the paralle-type compound eye and the overlap compound eye, and the detail of working principle, the detail of their working principle, apaptive changes under different lighting conditions and their structures.Chapter3, the proposal and achievement of the replication of the drosophila compound eyes by virtue of the soft lithography, the detail of materials and process of the experiments, measurement and calculation of important parameters of the replication of the compound eye and the results and discussion.Chapter4, we propose a curved compound eye imaging system based on replicated compound eye using soft lithography and introduce image conversion system converting the curved focal plane to a plane in order to gain imaging on CCD. Finally, ZEMAX simulation of the conversion system and its result are demonstrated.