Biologically Inspired Ultrathin Contact Imager for High-Resolution Imaging of Epidermal Ridges on Human Finger

Compound eyes exhibit compelling vision schemes due to their unique visual ultrastructures. Here, a biologically inspired ultrathin contact imager (BUCI) for high-resolution contact fingerprint imaging is reported. The BUCI contains ultrathin arrayed camera, light-emitting diode arrays, and light guide plate (LGP). The ultrathin arrayed camera is fully packaged with microlens arrays, variable micropinhole arrays (MLA-VMA), and a single complementary metal oxide semiconductor image sensor. The ultrathin arrayed camera shows a large field of view of 77.3 degrees and a constant MTF50 of 89.4 cycles mm(-1), relatively higher than a comparable single lens camera at the distance less than 36.8 mm. The channel images of a human fingertip are directly obtained by using frustrated total internal reflection and stitched to a single and high-resolution full-field image for a fingertip of 5.7 mm x 4.9 mm. The BUCI provides a new platform for high-resolution contact imaging in biometric or healthcare applications.