Flexible Micro-Scale Sensor Array for Non-Contact Electric Potential Imaging

Non-contact imaging of electric potentials with micro-metre resolution can provide relevant insights in material characterisation, electrostatic charge imaging and bio-sensing applications. However, scanning electric potential microscopes have been confined to rigid and single-probe devices, making them slow, prone to mechanical damage and complex to fabricate. In this work, we present a novel 5-element flexible array of electric potential probes with spatial resolution down to $20 \mu \mathrm{m}$ which reduces the scanning time by a factor of 5 when compared to a single probe device. This was achieved by combining flexible thin-film probes for active guarding and shielding with state-of-the art discrete conditioning circuits. The potential of this approach is showcased by using the fabricated array to image latent fingerprints deposited on an insulating surface by contact electrification. This is the first example of a micro-scale array of electric potential sensors.