Thermal cameras help us “see” heat instead of visible light.
They are used in many everyday technologies, from firefighters searching through smoke to night vision systems, remote temperature sensors, drones, robots and self-driving cars.
Now, researchers have found a simple way to make these cameras much more accurate without making them much more expensive.
The new study, published in Nature Sensors, was led by Professor Fengnian Xia and his research team.
They discovered that adding a very small transistor to existing thermal imaging technology can greatly improve its ability to detect tiny differences in temperature.
Thermal cameras work by detecting the heat that all objects naturally give off. They then turn this heat into an image, allowing people and machines to see things that may be hidden by darkness, smoke or fog.
Today, there are two main types of thermal imaging technology. The first type uses photon detectors.
These sensors are extremely accurate and can detect very small changes in heat. However, they must be cooled to extremely low temperatures to work properly. This makes them very expensive, so they are mostly used by the military, scientists and other specialized industries.
The second type is called a microbolometer. These devices are much cheaper, smaller and easier to carry around. They are widely used in firefighting, building inspections, security cameras and many other everyday applications. However, they are not nearly as sensitive as the more expensive cooled detectors.
One reason is the materials used inside microbolometers. They are usually made from vanadium oxide or amorphous silicon. These materials do not change their electrical resistance very much when their temperature changes. Because of this, they cannot detect small temperature differences as well as more advanced sensors.
Instead of searching for new materials, the researchers took a different approach. They added a tiny electronic component called a two-terminal NPN transistor. A transistor is commonly used in electronic circuits to control or amplify electrical signals.
The transistor creates a special feedback effect that makes the sensor much more sensitive to changes in temperature. It also allows researchers to adjust how strongly the sensor responds to heat.
The improvement was dramatic. The temperature coefficient of resistance, or TCR, increased from about 10% per kelvin to as much as 150% per kelvin. In simple terms, the sensor became far better at detecting small changes in heat, allowing thermal images to become clearer and more detailed.
The research team says the next step is to build working thermal imaging devices using this new technology. They also plan to add components that can detect mid-infrared heat, which could further improve performance. Finally, they hope to build the technology on silicon, the same material widely used to make computer chips.
If successful, this simple improvement could lead to a new generation of affordable thermal cameras that deliver much sharper images without the need for costly cooling systems, making advanced thermal imaging more accessible for many everyday uses.
