Scientists have developed a thermal imager built into a smartphone

Checking body temperature when entering public buildings has become a daily reality since the beginning

pandemics. This leads to queues.Thermal cameras can solve the problem, but they are expensive to install anywhere. Researchers at the Center for Optoelectronic Materials and Devices at the Korea Institute of Science and Technology have solved the problem by adapting bolometer technology for use in smartphones.

A bolometer is a thermal radiation detector thatinvented by Samuel Pierpont Langley in 1878. The new version of the microbolometer showed results close to accurate, even at temperatures of 100 ° C and above. The components of modern smartphones are usually designed to operate in temperatures up to 85 ° C. This means that such a sensor can be installed on the phone.

Traditional non-contact thermometers workconverting infrared radiation, which is emitted by all bodies with temperatures above absolute zero, into electric current. And already its value is subsequently recalculated, and the screen displays degrees Celsius or Fahrenheit. The higher the body temperature, the more intense the infrared radiation.

Modern thermal imagers are based on arraysmicrobolometers, which measure temperature more accurately than simple non-contact thermometers. Infrared radiation acts on the detector, causing a change in the magnitude of the electric current. At the same time, most modern microbolometers operate normally only at temperatures close to room temperature; at higher temperatures, there is a need for a cooling unit.

The most common microbolometers canwork only at or near room temperature, and for high temperature environments a separate cooling device is required. The Korean companies replaced the traditional detector material with a more heat-resistant one, making a film of vanadium dioxide that could show the same changes in electric current from room temperature to 100 ° C.

They also built an absorber into the microbolometerinfrared radiation, which maximized the absorption of infrared radiation by the device and increased its sensitivity by three times. During testing, the microbolometer was able to capture thermal images at 100 frames per second even at 100 ° C, which is about three to four times faster than conventional sensors.

In practice, this means that at a low pricethe microbolometer can not only be installed in telephones, but generally be used everywhere. For example, it will help the on-board systems of cars to detect sources of danger in the dark, in construction, it will allow you to quickly detect flaws in structures, and firefighters will be able to see better in smoke conditions.

Thermal imaging cameras based on inexpensivemicrobolometers that can operate at high temperatures are useful for night vision, detecting hazards in vehicles, structural defects in buildings, and helping firefighters observe smoke.

“Uncooled thermal imagers were initiallydeveloped for military purposes, such as remotely measuring the temperature of military objects or soldiers, said study author Won Joon Choi of the Center for Optoelectronic Materials and Devices at the Korea Institute of Science and Technology. "But now many other applications are possible."

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