High-linearity flexible capacitive pressure sensor array for cervical spine motion monitoring

： The prevalence of sedentary lifestyles has made cervical spondylosis a common chronic disease. Flexible sensing devices are developing toward higher force resolution and wider force detection ranges. This paper presents a flexible capacitive pressure sensing system designed for continuous monitoring of cervical spine motion. Ecoflex was selected to fabricate the dielectric layer, and a conical microstructure dielectric layer was designed to create a capacitive sensor array with high force resolution and high linearity. Test results demonstrate that the fabricated4×4capacitive pressure sensor array exhibits a full-scale sensitivity of 0.00167 kPa −1 within the range of 0～50kPa, with R 2 =0.9989. The loading time is 60 ms and the unloading time is 420 ms. Under a 10 kPa load, the maximum difference in capacitance change rate among individual pixels is only 0.19%. The sensor can resolve minute force variations as small as 0.1 kPa. Human wearable tests confirm that the system can accurately distinguish four typical cervical spine motions: raising the head, lowering the head, and left/right rotation. This sensing system provides a novel technological solution for wearable cervical spine health monitoring and rehabilitation assessment.