Development of flexible blood pressure sensor using piezoelectric single crystalline PMN-PT

Abstract

Blood pressure sensors in non-invasive methods are now increasing the demand for a healthcare function of wearable devices with an increase in the size of the wearable market and interest in people’s health. Currently, in the case of blood pressure measurement technology used in Samsung Galaxy Watch 3, the pulse wave’s waveform is analyzed and blood pressure is inferred through PPG (photoplethysmography) technology using LED. PPG is used as a medical device due to its high accuracy when measuring on thin-skinned fingertips, however it is difficult to measure accurately on thick-skinned wrists due to differences in LED transmittance. In this paper, we report the study of accurately acquiring pulse wave waveform through flexible piezoelectric device, not the existing used PPG technology, and analyzing the waveform to infer blood pressure. In order to obtain a high-accuracy pulse wave waveform, a high-sensitivity piezoelectric blood pressure sensor is implemented by transferring a single crystal PMN-PT with a high piezoelectric constant manufactured through a solid single crystal growth method onto a flexible substrate. In addition, blood pressure data is established through simultaneous measurement of OMRON's blood pressure meter which are previously certified as medical devices and flexible piezoelectric blood pressure sensor, and accurate blood pressure analogy is reported through PWA (Pulse Wave Analysis) method. This paper presents a blood pressure sensor using flexible piezoelectric material that has not been previously commercialized, and shows its usability as a wearable device of this technology.