Researchers develop color night vision device
Normal night vision devices translate infrared radiation into a monochromatic green image. Technology from a Chinese university is set to make darkness visible in multiple colors in the future.
Researchers in Beijing have developed night vision goggles that translate infrared radiation into a multi-colored image – instead of the typical green monochrome optics of classic image intensifiers. The system from the Beijing Institute of Technology combines infrared-sensitive quantum dots with a two-layer OLED display. It is designed to extract more details from darkness than previous technology.
At its core is a layer of mercury telluride quantum dots. These particles, about four nanometers in size, absorb infrared light up to two micrometers in wavelength. Unlike conventional semiconductor detectors, they do not provide a broad, uniform signal, but rather react depending on the wavelength and intensity of the incoming light. Longer wavelengths generate fewer charge carriers, shorter ones more. This creates a signal that contains information about the spectral distribution and brightness of the incident radiation.
This signal flows into a two-layer OLED display behind the detector layer. The first OLED layer consists of red-emitting phosphor, the second of a cyan phosphor. An energy barrier lies between them. If few positive charge carriers arrive, they remain in the red layer and the pixel glows dark red. If the number of charge carriers increases, the barrier saturates and more charges reach the second layer. Then the pixel also emits in cyan. The mixture and brightness of the light shift gradually. This creates a color image that carries both intensity and spectral information of the infrared light.
AR Glasses and Cyborg Implants
In laboratory tests, the system achieved a sensitivity, according to the study, that can resolve brightness differences in the infrared range about 200 times finer than a monochrome night vision device. The researchers integrated the technology into semi-transparent glasses with an active field of view of 3.6 square centimeters. Visible light passes through the structure largely unhindered. In an augmented reality mode, infrared information can be superimposed over normal vision. With an additional filter, a pure infrared mode would also be possible. The team also tested an application in implants. Night vision cyborgs, here we come.
The technology is still far from being a finished product. The glasses require an external power supply and have not been tested in everyday scenarios. It remains unclear how well the color coding works when many infrared sources with different temperatures and materials are simultaneously in the image. In addition, there is the material risk: mercury telluride is a heavy metal semiconductor. This raises questions about long-term stability and safety in case of skin contact. Before the system can become everyday night vision goggles or visual prostheses, further material studies, miniaturization, and long-term tests are needed.
My fingerprint often changes so drastically that my MacBook doesn't recognise it anymore. The reason? If I'm not clinging to a monitor or camera, I'm probably clinging to a rockface by the tips of my fingers.
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