Views: 0 Author: Site Editor Publish Time: 2026-02-12 Origin: Site
On January 21st, news broke that the CEA-Leti Institute in France has developed a novel optical sensing architecture that combines Micro LED and organic photodetector (OPD).
This solution integrates device design, electronics, and modeling techniques, aiming to enable multifunctional sensing applications for display screens without sacrificing image quality. The researchers specifically optimized the device for green light wavelengths, which are most suitable for extracting photoplethysmographic (PPG) signals, a biological signal commonly used for heart rate monitoring.
To verify this scheme, the research team designed a dedicated electronic platform capable of end-to-end evaluation of the entire signal chain, from the driving and emission of Micro LEDs, through the object under test, to the photoelectric detection and circuit readout.
The platform employs "lock-in amplifier technology" which can effectively suppress constant interference signals in the system, thereby significantly improving the signal-to-noise ratio. This is particularly important for biosensing detection as it helps extract weak effective signals from strong background noise.
During the system verification phase, researchers utilized a specially designed optical phantom to mimic the absorption and scattering properties of real biological tissues, thereby assessing its biosensing capabilities in a controlled and reproducible environment. By integrating experimental outcomes with theoretical analysis, the team deduced a mathematical model that effectively correlated the operating conditions of Micro LEDs, the sensitivity of the detector, and the reflectivity of the tested object with the ultimately detected signal.
The test results indicate that the co-packaged Micro LED device can achieve an optical power of 12 mW at a wavelength of 525 nm. In terms of detection, by precisely adjusting the thickness of the active layer material, the researchers optimized the responsivity of the detector to perfectly match the emission peak of the Micro LED, thereby achieving efficient signal reception at the target wavelength.
