Organic Pressure-Sensing Surfaces Fabricated by Lamination of Flexible Substrates

This paper presents the design and experimental characterization of large-area active matrixes on foil for pressure-sensing applications. Front-end circuits based on organic thin-film transistors on a flexible substrate are laminated with a foil hosting screen-printed PDVF-TrFE piezo sensors to create the complete flexible sensing systems with 6×10 sensing elements on a 16.5 cm×27.5 cm area. After defining the specifications based on the application scenarios, and designing two different front-end matrixes (A and B), the performance of the sensing surface B has been investigated in simulation. Numerical results show a readout speed of 5 kframe/s and 78.6 dB maximum signal-to-noise ratio with impact forces up to 50 kN. Experiments made with a prototype based on front end A confirm that the system can correctly reconstruct the impact profile of forces up to 50 kN obtained in a drop tower setup. Measurements of the front end circuit B show an input equivalent noise of 451 μV
_rms
and a 5% settling time of 13.8 μs, both adequate for the specified applications.