Infrared binoculars and cameras are often used by the military to see at night. These devices distinguish objects by the infrared radiation that they emit, with radiation level depending on the object's type and temperature. Although very effective, there is one major disadvantage: the detectors have to be cooled to about -258°F, which requires them to have a cryogenic cooling system. This leads to limited battery life, and relatively high weight and price.
For this reason, researchers from France's LETI (the Laboratory for Electronics, Technology, and Instrumentation) Laboratories are creating prototype infrared binoculars called "Bolide" that operate without a cryogenic cooling system. The binoculars use a detector devised at LETI's infrared laboratory, in CEA/Grenoble, southeastern France. The project is being developed in collaboration with French companies Sagem and Sofradir within the General Armanent Commission program.
With the new binoculars, cooled detectors are replaced with microbolometers that work at ambient temperatures. Bolometer sensors are used to measure infrared radiation or any other form of radiant energy. These microbolometers work in two stages using two superimposed materials: an absorber that converts the incident infrared radiation into a higher temperature, and a temperature sensor that converts this increase into electrical signals. These signals are then read using an integrated circuit that processes them. Each detector consists of a matrix of some 76,800 microbolometers measuring less than 50 micrometers in size. Each microbolometer is linked with a picture element (pixel) in the final image.
Although not able to perform as well as existing equipment in terms of range, Bolide night binoculars are said to be both lighter and less expensive. Initially, they will be used in military and space applications, as well as in the civil sector for preventive maintenance or monitoring industrial processes.
