Microfabrication of bioinspired curved artificial compound eyes: a review

Eyes are one of the most important organs for natural creatures to perceive external information. The curved compound eyes of insects endowing with merits of a wide field of view (FOV), high sensitivity and detecting quick moving targets have aroused extensive concern. There are mainly two categories of compound eyes in nature. One is apposition eyes which can avoid light crosstalk and the other is superposition ones with higher sensitivity. With the rapid development of micron and nano machining technologies, the fabrication techniques of compound eyes have experienced changes from waveguide self-writing initially to advanced femtosecond laser method through thermal reflow and other processes. The diameters of compound eyes varies from the original several hundreds micrometers to the smallest 5 µm currently, which is much closer to the natural ones. Therefore, a critical review is presented to systematically summary and compare the micromachining processes of curved artificial compound eyes in recent years from the perspective of microfabrication technology. Finally, we describe a broad applications including navigation and location, digital camera and rapid detection of moving objects as well as existing challenges and future perspective of curved artificial compound eyes. It is hoped that this review can help researchers to gain a better overall understanding of microfabrication in this field and push forward it to a new stage.