A flexible capacitive pressure sensor array for pulse diagnosis

Pulse diagnosis is one of major methods used in traditional Chinese medicine to evaluate a patient's health conditions. Development of a pulse diagnosis apparatus can lead to modernization and advancement of the field by providing more objective and accurate evaluations. This study aims at demonstrating real-time pulse measurement by using the developed flexible capacitive pressure sensors. A 5 × 5 sensor array of 0.75 cm × 1 cm in size was implemented by using flexible printed circuit boards and integrated with CMOS (complementary metal oxide semiconductor) switched-capacitor readout circuits. The sensing membrane has a 1.2-mm diameter and a 6-μm electrode gap. The measured average output sensitivity was 1.57 mV/mmHg. Real-time pulse measurement has been successfully demonstrated.