How Non-contact infrared thermometer works

What to use to measure human body temperature?

Since the beginning of modern medicine, body temperature has been an essential vital sign to our physical status. In the past glass thermometers including the mercury or alcohol were used --- whether they were oral or rectal type. They are reliable. However, for many reasons including the risk of broken glass, some countries have already stopped using them officially in the last decade. Since the millennium, ear thermometers have crowded the market. Though accurate, the discomforts made it difficult with young children feeling irritating. Most of the time, it is almost impossible to measure the temperature without waking up a sleeping baby or children.

Further technological advancement with semiconductor comes with the non-contact infrared thermometer (NCIT). Nowadays almost every clinic utilizes it for taking patient’s temperature because of its quick wake up time, fast reading and its non contact feature, making it a perfect for measuring large population under potential wildly spread disease.

How the temperature is being measured by NCIT?

In many ways a NCIT is very similar to the ear-thermometer in measuring technique. They differ with more sophisticated technologies applied, and NCIT is a very handy tool in reading the body temperature! Simply put it in front of the forehead or the temporal regions of the patient, the temperature reading will be measured in two seconds (+/-0.2°C or +/-0.36°F).  A lot of reference clip shown how to use a NCIT correctly.

At times, when reading the forehead or temporal region could be difficult. For example, patients rolling over to one side and the care takers would minimize disturbance, NCIT can also read other warm parts of the body like limbs to produce accurate results.

What used to be an invasive (even ear thermometer) process, it is now a hustle free gesture! Indeed, a very simplified screening procedure for everyone especially during a pandemic.

What is the theory of NCIT?

NCIT is based on thermopile technology. For the last 50 years, semiconductor manufacturing makes a low-cost single chip thermopile possible! Among them Excelitas Technologies, and Heimann Sensors are the two leaders in the industry. When exposing to infrared radiation, the thermopile will induce an electrical signal across. The signal will be captured and processed by a microcontroller system which in turn will display the temperature in a couple of seconds. Refer to Fig 1.

There are compensational ciruit in order to offset the object temperautre with the ambient temperature. That can make the reading more reliable. The combination of the sensor and the microcontroller plays an important role in the accuracy of the thermometer. 

Beside considering the accuracy, the customer service level and the warranty should also be your consideration. Click here to choose the one fit your need.

References:

https://www.heimannsensor.com/aboutus.php

https://www.excelitas.com/company-profile

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