Miniature NIR spectrometer for mobile applications

Abstract

To allow for adoption of optical spectroscopy in mobile and consumer devices, truly miniaturized, low-cost, mass-producible spectrometers are needed. We present such a miniature (4mm x 3.2mm x 3.3mm) LGA packaged CMOS spectrometer in the range of 650-900nm and 720-1000nm. It leverages a wafer-level patterned spectral filter technology. The devices include diffuse optics and integrated spectral calibration and embedded corrections processor for part-to-part stable and repeatable performance across input angles and temperature with 68dB dynamic range, 5nm spectral resolution and up to 70 spectra/s. The run-time spectral corrections allow for plug-and-play operation of the sensor, without any need for recalibration in the field. The sensor enables portable spectroscopic applications in smart agriculture, anti-counterfeit, food analysis and skin sensing. For example, the combination of high sensitivity and speed of the spectrometer enables high sampling rate measurement of PPG signals and accurate measurement of heart rate and blood oxygenation (SpO(2)).