FLIR 614004898, Руководство оператора

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Figure 13.4 Samuel P. Langley (1834–1906)
The improvement of infrared-detector sensitivity progressed slowly. Another major
breakthrough, made by Langley in 1880, was the invention of the bolometer. This
consisted of a thin blackened strip of platinum connected in one arm of a Wheatstone
bridge circuit upon which the infrared radiation was focused and to which a sensitive
galvanometer responded. This instrument is said to have been able to detect the heat
from a cow at a distance of 400 meters.
An English scientist, Sir James Dewar, first introduced the use of liquefied gases as
cooling agents (such as liquid nitrogen with a temperature of -196 °C (-320.8 °F)) in
low temperature research. In 1892 he invented a unique vacuum insulating container
in which it is possible to store liquefied gases for entire days. The common ‘thermos
bottle’, used for storing hot and cold drinks, is based upon his invention.
Between the years 1900 and 1920, the inventors of the world ‘discovered’ the infrared.
Many patents were issued for devices to detect personnel, artillery, aircraft, ships –
and even icebergs. The first operating systems, in the modern sense, began to be
developed during the 1914–18 war, when both sides had research programs devoted
to the military exploitation of the infrared. These programs included experimental
systems for enemy intrusion/detection, remote temperature sensing, secure commu-
nications, and ‘flying torpedo’ guidance. An infrared search system tested during this
period was able to detect an approaching airplane at a distance of 1.5 km (0.94 miles),
or a person more than 300 meters (984 ft.) away.
The most sensitive systems up to this time were all based upon variations of the
bolometer idea, but the period between the two wars saw the development of two
revolutionary new infrared detectors: the image converter and the photon detector.
At first, the image converter received the greatest attention by the military, because
it enabled an observer for the first time in history to literally ‘see in the dark’. However,
the sensitivity of the image converter was limited to the near infrared wavelengths,
and the most interesting military targets (i.e. enemy soldiers) had to be illuminated
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Publ. No. 1 557 544 Rev. a121 – ENGLISH (EN) – October 6, 2005