Planar touch sensors, as the pivotal component of accessible man-machine interaction system, are capable of recognizing tactile information through monitoring either capacitance or resistive change, and they have promoted the revolutionary development of portable electronics. Recent advances from device design to manufacturing technique endowed the touch sensor with various novel characteristics. For these devices, physical contact between sensors and objects is essential for triggering the response regardless the applied weight and shapes of the objects, e.g., as a contact-mode-based sensors that are “blind” to the approaching objects. To address this issue, proximity sensing as a complemental function can be incorporated into these artificial skin and provide them dual-functional sensing capability, which could expand the applications of common single functional pressure sensors, for instance helpingthe robots to detect objects for collision avoidance and take pre-action in the dark, or enabling the smart phone to sense the hovering fingers with accurate positions and distance from the screen.
Prof. Bin Hu’s group demonstrated the continuous response of pressure and proximity sensing using a highly transparent film, it is capable ofquantitatively detecting and distinguishing the objects in three different states including proximity, contact and pressure-loading by monitoring capacitance change between two transparent electrodes made of silver nanowires (AgNWs) network. The device also shows good multiple points spatial resolution in proximity mode which has rarely been reported.This powerful integrated proximity-contact sensor can be applied in the field like smart phone, game machines and robots, but not limit to these.
This work was supported by the NSFC (No: 61204001), the Fundamental Research Funds for the Central Universities of China (2014QN013), thanks to the facility support of the Center for Nanoscale Characterization & Devices (CNCD), WNLO of HUST.This research was just published in Nano Research(DOI 10.1007/s12274-014-0510-3)