A bioinspired three-dimensional integrated e-skin for multiple mechanical stimuli recognition

Spatiotemporal recognition of multiple mechanical stimuli is essential for electronic skin (e-skin), which can provide more complete and accurate interaction information to enable elaborated functions, such as gesture recognition, object manipulation, and fine tactile discrimination. However, nonspecific sensor response and performance sacrifice for integration limit the perceptual capability of the current systems. Here, we report a bioinspired e-skin that can measure strain, shear and pressure independently with direction information using three-dimensional integrated, mechanically isolated multiple sensors. Novel microstructures of collapsed nanocone clusters, hemi-ellipsoids, and wrinkles are introduced in different sensors to achieve a gauge factor of 6 with a linear working range of 80% (linearity > 0.99) for strain, a sensitivity of 0.1 N−1 for shear force, and a sensitivity of 3.78 kPa−1 for pressure, and all of these sensors possess short response times on the order of 100 ms. The independent, highly sensitive, and fast response of these sensors makes real-time recording and mapping of multiple mechanical stimuli to be achieved. Multi-touch gesture recognition and perception of a red bean (0.065 g) in the hand are demonstrated to illustrate the potential applications in wearables, robotics and bionic prostheses.