Fig. 1: Hourglass-shaped microstructured capacitive sensors as tactile sensory receptors for energy-efficient near-sensor computing.

a Conceptual illustration of a pressure sensor with a microstructured dielectric layer, mimicking the surface of the starfish, Astropecten polyacanthus, designed for energy-efficient near-sensor computing. b Applications of tactile near-sensor computing with high energy efficiency. c A flexible dielectric layer featuring hourglass-shaped microstructures. Polydimethylsiloxane (PDMS) was used as the dielectric material. Scale bar, 1.5 cm. The inset image shows the microstructures on the film, observed using field emission scanning electron microscopy. Scale bar, 400 μm. d Normalized capacitive responses of pressure sensors with single and double dielectric layers incorporating hourglass-shaped microstructures, and a conventional flat layer. e Numerical simulation results of mechanical stresses at the microstructures of the sensor with a single dielectric layer in response to deformation. To accurately reflect the real device structure, where the microstructured pattern is periodically repeated across the sensor, and more precisely analyze the stress concentration, we incorporated periodic boundary conditions in the finite element simulation.