A Flexible Thin-Film Pressure Sensor Based on Thermal Conduction Mechanism for Pressure, Orientation, and Mapping Signal Acquisition

In recent years, high-performance flexible pressure sensors have boomed with wide applications in touch screens, wearable electronic devices, human–machine interface, real-time physiological signal perception, and other fields, and have drawn extensive research attention in the field of wearable electronic devices and intelligent E-skin. However, because the “function” of sensors is often incompatible with a “simple” manufacturing strategy, the flexible sensor can hardly simultaneously meet the objectives of low cost and excellent performance. Herein, we propose a facile and low-cost flexible thermal resistive pressure sensor (FTRPS) based on the heat transfer sensing mechanism. The device consists of an ultra-thin thermal sensing film (thermal detectors: platinum resistors on Parylene-C film: $20\,\mu \text{m}$ ) and an elastomer pressure converter (Dragon Skin). The pressure value can be transduced via the elastomer deformation and monitored through the heat loss of the thermal sensing film. Leveraging different Young’s modulus of the elastomer, the measurement range of different sensors can be tuned with material selection. The fabricated sensor exhibits high linearity ( ${R}^{2}$ : 0.996) for the whole measurement range and realizes the pressure orientation sensing function with the circular thermal detector design. Furthermore, the single sensor has been validated in chess piece recognition, and the successful application of the sensor matrix in the pressure mapping of a letter protruding indicates that the FTRPS can be a part of wearable devices and human–machine interfaces. The proposed FTRPS can be used in mass production and promotes the application of flexible pressure sensors.