The way for cheaper and smaller thermal security cameras is being paved by the work of a team of French researchers, who developed an IR (thermal infrared) with a silicon lens.
The new lens, which is made of a material much cheaper than those widely used today, is the thickness of a fingernail with a diameter smaller than a No. 2 pencil. Although its resolution is not high, it is able to indicate the presence and some general features of a face.
The researchers presented their research results in a paper published in the Optical Society's Optics Letters. The potential applications of this technology are more focused on the surveillance sector, allowing for the development of cheaper security systems in the long term, especially for home use.
“It could detect people in a room, or a street corner, or a dark alley,” says Tatiana Groulois, a PhD candidate at the French aerospace laboratory ONERA, where the prototype was developed in collaboration with researchers from the French company ULIS, the Institut d’Optique and the French National Center for Scientific Research (CNRS). The new camera has a wide 130-degree field of view and very good performance in low-light conditions. It is effective over a wide range of infrared wavelengths (7-14 micrometers), demonstrating high sensitivity to differences in temperature.
The researchers believe their lens could revolutionize thermal infrared (IR) security cameras. “In recent years, great efforts have been made to reduce the price of uncooled long-wavelength IR detectors,” Groulois notes. “Thanks to the thinness of the lens, this work paves the way for inexpensive unconventional materials that have not been used ‘traditionally’.”.
Until now, materials such as silicon could not be used in such lenses because a large percentage of light was absorbed rather than passed through the material. However, the French researchers have made the lens very thin by turning to a special type of lens, called a Fresnel lens, a variant of which is used in lighthouses and cinemas/theaters.
Thermal Infrared naftemporiki.gr
