To achieve the human sense of touch, a strain sensor needs to be coupled with a pressure sensor to identify the compliance of the contacted material. However, monitoring the pressure-strain signals simultaneously and ensuring no coupling effect between the two signals is the technical bottleneck for the flexible tactile sensor to. Herein, a composite flexible sensor based on microstructures of lotus leaf is designed and manufactured, which integrates the capacitive pressure sensor and the resistance strain sensor into one pixel to realize the simultaneous detection of pressure and strain. The electrode layer of the capacitance sensor also plays the role of the resistance strain sensor, which greatly simplifies the structure of the composite flexible sensor and obtains the compact size to integrate more easily. The device can simultaneously detect pressure and deformation, and more importantly, there is no coupling effect between the two kinds of signals. Here, the sensor has high pressure sensitivity (0.784 kPa-1 when pressure less than 100 kPa), high strain sensitivity (gauge factor = 4.03 for strain 0-40%), and can identify materials with different compliance, which indicates the tactile ability as the human skin performs.
Keywords: compliance; composite flexible sensors; coupling effects; lotus leaves.
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