A new era of smart displays
“A multifunction display does more than just providing display content—it captures and interacts with its surroundings," says Michaël Pelissier, optoelectronic systems engineer at CEA-Leti and head of the multifunction displays project.
This technology enables remote interaction through gesture recognition, secure access via fingerprint detection across the entire screen surface, and even the extraction of physiological parameters from a person in contact with the display.
At the heart of this innovation lies micro-LED technology, a key differentiator for CEA-Leti.
"Micro-LEDs provide outstanding brightness while maintaining a minimal footprint, leaving room to integrate additional functions and offering the potential for transparent displays," adds Michaël Pelissier. "This project takes a multidisciplinary approach, from system specification to technological implementation, ensuring a comprehensive and cutting-edge solution."
Bridging technologies for seamless integration
The primary technological challenge in developing these multifunction displays is the seamless co-integration of heterogeneous technologies—specifically, micro-LEDs and photodetectors.
"Using microelectronics fabrication processes, we ensure compatibility between these two key components," explains Paolo De Martino, optoelectronic device engineer at CEA-Leti. “We start by preparing a matrix of micro-LEDs, which serve as both the display and illumination source. Then, we integrate a matrix of photodetectors that capture reflected light signals from the illuminated scene."
CEA-Leti's advanced cleanroom facilities enable researchers to achieve scales of precision for micro-LEDs fabrication that are a thousand times smaller than the width of a human hair.
Leveraging CMOS for European sovereignty
Advanced multifunction displays require highly efficient control circuits – a challenge that can be well met by CMOS technology:
"CMOS is used everywhere—from smartphone cameras to computers—because it enables both analog and digital functions through transistors," explains Margaux Vigier, analog circuit design researcher at CEA-Leti. "We see a strong advantage in using CMOS for multifunction displays, not only because of its superior performance, but also because it could support a shift towards European-based manufacturing in a context where most displays today are produced in Asia."
CMOS technology also allows the integration of complex functions within the display itself. Leveraging years of cutting-edge research and expertise, CEA-Leti teams are able to simultaneously power micro-LEDs, capture signals and even add near-sensor processing to reduce data transfer between the circuit and external systems.
"Such efficiency is crucial for optimal data exchange as well as the extraction of valuable insights from the display environment," underlines Margaux Vigier.
Unlocking new health applications
One of the most promising applications of multifunction displays lies in physiological monitoring.
"With this technology, we can measure physiological parameters directly from the person in contact with the display surface," says Emma Villeneuve, signal processing researcher at CEA-Leti. "CEA-Leti brings three core areas of expertise to this field: optics, signal processing and regulatory compliance."
CEA-Leti's expertise in optics is put to good use in order to study how light propagates through human skin using experimental setups, skin models and optical simulators. The organization's expertise in signal processing is applied to develop algorithms capable of extracting heart rate information from optical signals. And finally, regulatory expertise ensures that devices are safe for human use before clinical testing and deployment.
A revolutionary step in display technology
By combining micro-LEDs, advanced photodetection, CMOS design and cutting-edge signal processing, CEA-Leti's multifunction displays mark a significant leap forward in display technology. Their ability to integrate biometric authentication, gesture recognition and health monitoring directly into displays paves the way for for industries ranging from consumer electronics to medical diagnostics. As these technologies move toward commercialization, multifunction displays are set to become a defining feature of next-generation interactive systems.