The way to cheaper and smaller sized thermals cameras ασφαλείας ανοίγει η δουλειά ομάδας γάλλων ερευνητών, που ανέπτυξαν κάμερα IR (thermal infrared) with a silicon lens.
The new lens, which is made from a material much cheaper than those in common use today, is as thick as 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 characteristics of one person.
The researchers presented the results of their research in a paper published in Optıcs Letters of the OSA (Optical Society). The potential applications of this technology are more focused in the field of surveillance, allowing in the long term the development of cheaper security systems, especially for home use.
"It could detect people in a room, or the corner of a street, or a dark alley," says Tatiana Grulois, 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 field of view of 130 degrees and very good performance in low light conditions. It is effective over a wide range of infrared light wavelengths (7-14 micrometers), exhibiting great sensitivity to temperature differences.
The researchers estimate that their lens may revolutionize the field of infrared security cameras (Thermal Infrared). "In recent years, great efforts have been made to reduce the price of uncooled long-wavelength IR detectors," Grulois notes. "Thanks to the small thickness of the lens, this work paves the way for inexpensive unconventional materials that were not 'traditionally' used."
Until now materials such as silicon could not be used in such lenses because much of the light was absorbed instead of passing through the material. The French researchers, however, made the lens very thin by turning to a special type of lens, the so-called Fresnel lens,change of which is used in lighthouses and cinema/theater halls.
Thermal Infrared naftemporiki.gr
