Revolutionizing Night Vision: Meet the Game-Changing OLED Technology!

new efficient night vision technology

New OLED Device Converts Infrared to Visible Light: Lightweight, Efficient Night Vision Technology

The innovative device, measuring narrower than a human hair, adeptly amplifies and transforms near-infrared light into visible light, heralding both energy efficiency and prolonged battery life. Researchers at the University of Michigan have pioneered a novel type of organic light-emitting diode (OLED) that holds the potential to supplant cumbersome night vision goggles with lightweight, cost-effective glasses, enhancing their practicality for prolonged usage.

A notable memory effect observed in these OLEDs may also pave the way for advanced computer vision systems capable of sensing and interpreting incoming light signals and images.

Current night vision technologies depend on image intensifiers, which convert incoming near-infrared light into electrons. These electrons then accelerate through a vacuum into a compact disc with numerous tiny channels. As they traverse these channels, they collide with the walls, resulting in the release of thousands of additional electrons that subsequently strike a phosphor screen, transforming them into visible light. This intricate process amplifies the incoming light by a staggering 10,000 times, allowing users to perceive their surroundings in the dark.

new efficient night vision technology: New OLED Device: Enhanced Efficiency and Portability

The newly engineered OLED device also converts near-infrared light into visible light, achieving more than 100-fold amplification, all while eschewing the heavy weight, high voltage, and bulky vacuum chamber associated with traditional image intensifiers. The researchers assert that further optimization of the device’s design could yield even greater amplification.

“One of the most compelling attributes of this innovative method is its capacity to amplify light within an ultrathin film stack measuring less than a micron in thickness—considerably thinner than a human hair, which typically spans about 50 microns,” explained Chris Giebink, a U-M professor of electrical and computer engineering and physics, and a corresponding author of the study published in Nature Photonics. The reduced voltage requirement compared to traditional image intensifiers significantly diminishes power consumption, thereby enhancing battery longevity.

The device functions through the integration of a photon-absorbing layer that converts infrared light into electrons, combined with a five-layer stack of OLEDs, where those electrons are subsequently transformed into visible light photons. Ideally, each electron that traverses the OLED stack generates five photons.

new efficient night vision technology: Positive Feedback Mechanism for Enhanced Output

Some of the emitted photons are directed towards the user’s eyes, while others are reabsorbed into the photon-absorbing layer, generating additional electrons that cycle through the OLED in a positive feedback loop. This cascading reaction substantially amplifies the output light relative to the input light.

Prior OLEDs were capable of converting near-infrared light to visible light but lacked any gain, resulting in a one-to-one correlation of input to output photons.

“This research signifies the inaugural demonstration of substantial photon gain in a thin film device,” stated Raju Lampande, a U-M postdoctoral research fellow in electrical and computer engineering and the lead author of the study. The device also exhibits memory-like characteristics, which could have implications for computer vision. This phenomenon, known as hysteresis, indicates that its light output at any moment is influenced by the intensity and duration of prior illumination.

“Typically, when you illuminate an upconversion OLED, it produces light, and ceases upon the removal of that illumination. This device, however, can remain ‘on’ and retain information over time, which is quite rare,” remarked Giebink.

While this memory behavior presents certain challenges for night vision applications, it also offers potential for image processing that mirrors the human visual system—where biological neurons transmit signals based on the timing and strength of incoming stimuli. The ability to retain past inputs could position these OLEDs as viable candidates for neuron-like connections, enabling the interpretation and classification of input images without necessitating separate data processing units.

The researchers fabricated the device using readily available materials and methods prevalent in the OLED manufacturing industry, enhancing both the cost-effectiveness and scalability of future applications for this technology.

Reference

“Positive-feedback organic light-emitting diodes and upconverters” by Raju Lampande et al., 13 September 2024, Nature Photonics. DOI: 10.1038/s41566-024-01520-0

This work was conducted in partnership with OLEDWorks, a manufacturer of OLED lighting products, and RTX, an aerospace and defense contractor. The technology is patent-pending by OLEDWorks and Penn State University, where the research initially commenced prior to Giebink’s transition to U-M. Funding for this research was provided by DARPA (Award No. HR0011-22-C-0053).