Spherical imaging array based on bioelectronic photoreceptors

Abstract

The performance of wide field-of-view (FOV) and omni-directional sensors are often limited by the complex optics used to project three-dimensional world points onto the planar surface of a charged-couple device (CCD) or CMOS array. Recent advances in the design and development of a spherical imaging system that exploits the fast photoelectric signals generated by dried bacteriorhodopsin (bR) films are described in this paper. The bendable, lightweight and durable bRbased photocell array is manufactured on an indium-tin-oxide (ITO) coated plastic film using Electrophoretic Sedimentation technique (EPS). The effective sensing area of each pixel in the preliminary prototype is 2×2 mm 2 , separated by 1mm and arranged in a 4×4 array. When exposed to light, the differential response characteristic is attributed to charge displacement and recombination within the bR molecule, as well as loading effects of the attached amplifier. The peak spectral response occurs at 568nm and is linear over the tested light power range of 200µW to 12mW. Response remains linear at the other tested wavelengths, but at reduced signal amplitude. Excess material between the bR sensing elements can be cut from the plastic substrate to increase structure flexibility and permit the array of photodetectors to be wrapped around the exterior, or adhered to the interior, of a sphere.