Ultrathin Tactile Sensors with Directional Sensitivity and a High Spatial Resolution

An ultrathin tactile sensor with directional sensitivity and capable of mapping at a high spatial resolution is proposed and demonstrated. Each sensor node consists of two gallium nitride (GaN) nanopillar light-emitting diodes. Shear stress applied on the nanopillars causes the electrons and holes to separate in the radial direction and reduces the light intensity emitted from the nanopillars. A sensor array comprising 64 sensor nodes was designed and fabricated. Two-dimensional directional sensitivity was experimentally confirmed with a dynamic range of 1-30 mN and an accuracy of +/- 1.3 mN. Tracking and mapping of an external force moving across the sensor array were also demonstrated. Finally, the proposed tactile sensor's sensitivity was tested with a fingertip gently moving across the sensor array. The sensor successfully registered the finger movement's direction and fingerprint pattern.

Automated summary

An ultrathin tactile sensor with directional sensitivity, utilizing GaN nanopillar LEDs, demonstrates high spatial resolution mapping. The sensor array exhibits two-dimensional directional sensitivity with a dynamic range of 1-30 mN and an accuracy of +/-1.3 mN. The sensor successfully tracks and maps external force movements, while also registering fingertip movements and fingerprint patterns.