Engineer Develops Eyeball-Like Image Sensor Based On Kirigami Art

A mechanical engineer has developed a camera with what is described as a “curved” and eyeball-like adaptable imaging sensor that is based on the Japanese art of cutting and folding paper (kirigami) which, according to him, could improve the quality of certain types of cameras.

Modern image sensors use a conventional rigid, flat surface to record light and translate it into images and use glass or plastic elements in lenses of varying sizes to correct visual aberrations. Corn University of Houston Professor of Mechanical Engineering Cunjian Yu has developed a sensor that can bend like a human eye and work with a single lens while correcting visual aberrations, while providing other benefits such as a wide viewing angle and size. compact.

“Existing curved imagers are either flexible but not compatible with adjustable focal surfaces, or expandable but with low pixel density and pixel fill factors,” Yu writes in Natural electronics. “The new kirigami design imager has a high pre-stretch pixel fill factor of 78% and can retain its optoelectronic performance while biaxially stretched by 30%.”

Yu bends the sensors using an array of extremely fine silicon pixels with a kirigami design using what’s called a Conformal Additive Pad Printing (CAS) process, a manufacturing technology that was invented in his lab. The University of Houston describes the CAS printing process as one where an “elastomeric” – or stretchy – balloon with a sticky coating is inflated and used as a stamping medium to press down on a pre-made device to pick up electronics and print on curved surfaces.

Kirigami is a method of Japanese paper art that differs from origami in that cutting is incorporated rather than simply folding the paper. The same principles are used in Yu’s process which makes fine cuts in the sensor sheet to allow it to stretch and bend. Thin cuts form a sort of “mesh” that gains flexibility without sacrificing pixel density.

“The new adaptive imager can achieve focused views of objects at different distances by combining a concave-shaped camera printed on a magnetic rubber sheet with an adjustable lens,” Yu explains. “Adaptive optical focus is achieved by adjusting both the focal length of the lens and the curvature of the imager, which enables far and near objects to be clearly imaged with low aberration.”

Yu thinks the sensor design will be particularly useful for endoscopes, night-vision goggles, artificial compound eyes, or fish-eye cameras. The complete article on optoelectronic pixels with kirigami design is published on Nature Electronique.

Picture credits: The header image shows a diagram of a stretched kirigami sheet, via the University of Houston.

Michael C. Garrison