Under Display Ambient Light Sensor for non-Invasive Vital Signs Monitoring

This research details the cutting-edge application of an Ambient Light Sensor (ALS) placed behind an Organic Light Emitting Diode (OLED) display for obtaining biomedical optical signals, leveraging the display's inherent light emission. It is the first instance of an ALS sensor being strategically placed behind a display to measure vital signs, capturing the light from the display as it reflects off the body. This method is designed to simplify integration, reducing both costs and the size of such technology in devices with displays. Performance was quantified by calculating the signal-to-noise ratio (SNR) and estimating heart rate (HR) to benchmark against the gold standard. Initial tests demonstrated an average SNR of 12.88 dB and a root mean square error (RMSE) in HR measurement of 2.65 bpm compared to the gold standard.