IR Thermometer- one of the weapons against COVID-19

Coronavirus is a zoonotic disease that allows human to human transmission and raised global health concerns. Common symptoms due to this virus are cough, tiredness, cold and fever. No any particular vaccine is available to prevent this spread. The sudden rise in number of coronavirus cases has caused the nations across the globe to take steps to stop the spread. For this, there has been a need of checking body temperatures regularly. In such cases, mercury thermometers are not used. So, it is advisable to use forehead thermometers known as infrared (IR) thermometers.

Infrared thermometers are used to detect body temperature by not contacting the patient’s body. It checks the human temperature by sensing the infrared energy radiated by the body. Infrared sensor detectors are of two types-

• Photon detector- radiation absorption process directly produces measurable effect i.e. provides reading on screen
• Thermal detector- first convert absorbed incident radiation into heat and then produce measurable effect.

   

   Photon detectors consist of materials which are difficult to grow and fabricate and hence are not much effective. Pyroelectric, bolometer, thermopiles are the sensors belong to the category of thermal detectors. Pyroelectric materials have much higher responsivity and specific detectivity, which is not preferable. Most of the companies manufacture thermopile based thermometers. The sensitivity of this sensor depends upon photosensitive area. Whereas bolometric detectors are independent of photosensitive area, which is its plus point. These detectors show high performance in lower cost. Bolometric materials have large temperature coefficient to resistance ratio (TCR) and low noise equivalent power (NEP) and because of these properties, they are preferred to be used in IR thermometers. 

   Infrared bolometric detectors operated at room temperature offer a large number of competitive advantages in terms of cost, operational convenience, higher reliability, reduced power consumption, small footprint and reduced weight.