Biologically inspired ultrathin array imager for point of care microscopy applications

Abstract

The very intriguing and unique structures that exist in nature have been a great inspiration for the study of various imaging systems. Among them, the compound eye structure of insects is the most well-known optical structure, and unlike the human eye, it is composed of tens to hundreds of optical units called ‘omatidia’. This optical unit is composed of microlenses and photoreceptor cells and has a wide field of view, low aberrations, and large depth of field. However, in addition, the insect eye has the advantage that it can exist in a very compact structure because the focal length of the microlens is short, and also has the feature of having a short minimum working distance. This study attempted to develop a close-up imaging system based on these characteristics. A reverse microlens array was fabricated by simulating the microlens of an insect eye, and a light absorption layer was placed in front of the lens to prevent optical crosstalk. The manufactured ultrathin array imager obtained high-resolution images at a close distance, and it was possible to observe a wider area compared to the conventional microscope. Fingerprint imaging, microscopic imaging, and fluorescence imaging were performed in this study using this imaging system. The proposed ultrathin array imager can be used as a variety of sensors and is expected to provide a new alternative in conventional microscopes.