How does an Infrared thermometer and is it safe for humans?

How does an Infrared thermometer and is it safe for humans?

Many people assume that infrared thermometers can harm the brain because they emit LASER. However, this statement is not true because the infrared thermometer is quite safe. Thermogun is a type of infrared thermometer for measuring body temperature which is generally pointed at the forehead.

This tool is the mainstay of screening for COVID-19 with fever symptoms, this tool is available at almost every entrance to public places and offices. Visitors or employees with a temperature above 37.5 are prohibited from entering and are asked to go to a health care facility. To get yourself a reliable and high quality infrared thermometer in Sri Lanka, check out

However, in recent days the public has been troubled by viral videos on social media stating that this tool is dangerous because it is considered to use LASER and damages the brain. Is this true?

How does an infrared thermometer work

Unlike the digital thermometer or mercury thermometer which uses the principle of conduction heat distribution. This thermometer uses the principle of heat distribution through radiation. In the principles of medical physics, any object with a temperature greater than 0 Kelvin will release electromagnetic radiation or often called black body radiation (Wien’s Law). 

Kelvin (K) is the standard unit for temperature with a conversion of 0 which is equivalent to 273 K. The range of normal human body temperature (36 – 37.5 ) is in the infrared spectrum when viewed from the range of electromagnetic radiation. 

Radiation energy from the surface of the body is captured and then converted into electrical energy and displayed in a digital number of degrees’ Celsius temperature on the infrared thermometer. Similar technological principles are used in thermal cameras for temperature screening at airports as well as thermal goggles in the military to detect someone’s presence at night.

Infrared thermometers are generally available in the market to detect eardrum temperature (ear thermometer) or forehead temperature (forehead thermometer). The forehead thermometer is more suitable to screen the symptoms of COVID-19 fever because it only needs to be “shot” to the forehead with no need of direct contact with the skin.

This thermometer detects the temperature of the temporal artery on the forehead to forecast the body temperature of someone. One thing you should pay attention to when it comes with the accuracy is that it is influenced by angle and distance of object being measured from the tool. In this case, the result may change when you check it again.

The common parameter to get an accurate result of is the ration between the measuring point and the distance. It should be 12: 1 for the accurate result. It means that if you want to measure ​​1 square cm point, you must put the thermometer 12 cm away from the point. 

It is the actual function of the laser in a thermogun or infrared thermometer. It can assist the user to get the center point where he or she has to measure. However, laser thermogun is usually only used for industrial thermal measurement purposes. However, you can still use it for medical purposes if you want.

What is a LASER?

A laser is an amplification of light through a simulated beam. This monochromatic light has the ultimate reliability of a coherent light beam. As it is also used on CD / DVD player and used as a cutter for medical purposes. However, it has been adjusted based on its function because it is dangerous if it is too great. 

Several industrial infrared thermometers use a laser with low energy. But, the laser feature used is only for a pointer in order to get accurate direction. Thus, it does not correlate the laser and the function to measure the temperature. 

Is the laser harmful to our brain? Since it is only used for a pointer, the laser will not endanger our brain at all. However, you should not shoot the laser light to the eyes because the laser may harm our retina.

Clare Louise