Did you know? Infrared thermometers were a defence technology that become a household staple

The defence industry is known for creating advanced technologies to solve tough problems, often under high-pressure conditions. One great example of this is the infrared thermometer. Originally developed for military and aerospace use – for improving night vision and detecting heat – this technology has now become a common tool in everyday life. The cutting-edge research and development in the defence sector pushes the boundaries of what's possible, leading to breakthroughs that can eventually find their way into our homes and everyday routines. Whether it's used in healthcare to take quick, contactless temperatures, in kitchens to check if food is cooked, or in homes to maintain heating systems, infrared thermometers show how inventions made for defence can end up benefiting all of us in practical and helpful ways.

Military and aerospace origins of infrared thermometers

The ability to detect infrared radiation was a significant technological advancement in the mid-20th century, with research beginning in the 1940s and 1950s to find ways of making night vision devices and thermal imaging systems for military and aerospace applications. These systems allowed for the detection of heat coming from by objects, enabling visibility in complete darkness, and the ability to detect heat sources from a distance.

As infrared technology advanced, it became possible to measure the temperature of objects based on the infrared radiation they emit. This led to the development of infrared thermometers, which could measure temperature without making physical contact with the object being measured – a huge breakthrough!

How infrared thermometers work

Infrared thermometers work by picking up the infrared radiation (that’s another word for heat) emitted by an object. All objects emit infrared energy, and the amount of this energy increases with the temperature of the object.

The thermometer contains a lens that focuses the infrared radiation onto a detector, called a thermopile. The thermopile converts this radiation into an electrical signal. This signal is then processed by the thermometer's electronics to calculate the temperature, which is displayed on the device.

Why are infrared thermometers useful?

Because they measure temperature from a distance, infrared thermometers are ideal for situations where the object is too hot, dangerous, or difficult to reach. So after their initial use in military and aerospace contexts, infrared thermometers found many uses in other areas.

Medical use: Infrared thermometers became important in the healthcare industry for measuring body temperature without contact. During the COVID-19 pandemic, infrared thermometers became widely used to allow rapid temperature screening of people in public spaces and events, and schools and workplaces.

Manufacturing: In manufacturing, infrared thermometers are used to monitor the temperature of machinery, materials, and processes without needing to interrupt production. This is important in processes where temperature control is needed, such as in metal forging, plastics, and electronics manufacturing.

Car industry: Mechanics can use infrared thermometers to check the temperature of engines, brakes, and other components without needing to disassemble them, allowing for quick diagnostics.

Food safety: Infrared thermometers are being used to make sure refrigerated and frozen food remain at safe temperatures in whilst being transported and stored.

Home safety and efficiency: infrared thermometers are being used to check the performance of heating, ventilation, and air conditioning systems; and can quickly identify temperature imbalances, check for leaks, and check the efficiency of insulation. They are also used to find hotspots and potential safety hazards in electrical systems.

Scientific research: infrared thermometers are being used in environmental monitoring to measure the temperature of surfaces, water, and the atmosphere. They are also used in climate studies to track temperature changes in various ecosystems. And in laboratories, infrared thermometers make it possible to take accurate temperature measurements in experiments where touching the sample could affect the research, or where the sample is hazardous.

Infrared thermometers are one of many technologies that originated in military and aerospace research, and has since become essential in everyday life. Their ability to provide accurate, non-contact temperature measurements has made them invaluable across a wide range of industries; showing how technological innovations developed for specialised uses, often find applicability in broader, more general contexts.