New thermal imaging sensor technology is showing promise for enhancements in smartphone and autonomous vehicle applications.
Developed by a team from the Korea Institute of Science and Technology (KIST) and Sungkyunkwan University (SKKU), both in South Korea, the technology can operate at temperatures up to 100°C. It doesn’t require a cooling device, as it can detect and convert infrared (IR) light generated by heat into electrical signals.1
To maintain stability at that 100°C threshold, the researchers used a vanadium dioxide (VO2)-B film, an IR absorber that can soak in a large amount of external IR light. Thus, heat signatures were detected with about three times more sensitivity and converted into electrical signals, according to the researchers. The team notes that the device can obtain the same level of IR signals at 100°C as it can at room temperature. In fact, the researchers found that heat signatures were detected with 3X more sensitivity and converted into electrical signals, thanks to the IR absorber.
Higher speeds, higher efficiency
The sensor has demonstrated around 3 ms of response time, even at 100°C, which is about 3–4X faster than conventional methods. This allows it to capture thermal images at 100 fps—traditionally, such technology has been able to capture less than 50 fps. Such speed could make the new sensor especially effective in smartphones.
In the wake of the COVID-19 pandemic, and the subsequent need for testing for the virus, thermal imaging sensors are being used to detect and capture images of the body’s heat signatures. Incorporation of such sensors into smartphones as “portable features to create the add-on function of measuring [body] temperature in real time” could make COVID-19 testing even safer and more efficient.
The new thermal imaging sensors also show great promise for safer autonomous vehicles.
According to the researchers, existing systems possess limitations in affordability and with regard to operating temperatures. Integration into smartphones and autonomous vehicles require the sensors to operate at a stable level at temperatures of 85°C (smartphones) and 125°C (autonomous vehicles). Conventional thermal imaging sensors require an independent cooling device, which are not only expensive, the researchers note, but they cannot typically operate well at such high temperatures.
“We have developed a technology that could dramatically reduce the production cost of thermal-imaging sensors,” says lead researcher Dr. Won Jun Choi, of the Center for Opto-Electronic Materials and Devices at KIST, adding that the new sensor is more responsive and quicker than conventional sensors. “We expect this to accelerate the use of thermal imaging sensors in the military supply, smartphone, and autonomous vehicle industries.”
1. H. J. Lee, Appl. Surf. Sci., 547, 149142 (2021); https://doi.org/10.1016/j.apsusc.2021.149142.