Nonintrusive measurement of heart rate using a flexible sensor array

Wide interest in wearable technology has brought progresses in wrist-worn, nonintrusive bio-signal measurement techniques. However, previous wrist-worn devices have rigid form-factors, causing them to be vulnerable to motion artifacts. In this paper, we propose a wrist-worn, nonintrusive heart rate sensing module which has an array of sensors mounted on a flexible band. Its flexibility allows it to fit users with various wrist diameters and improves robustness to motion artifacts. We adopted wire bonding techniques which allowed the resulting module to be small and thin like a wrist watch.