Technology has been developed for low-cost thermal imaging sensors that work well at temperatures up to 100 ° C. Probably active use in thermal imaging applications in smartphones and autonomous vehicles
Thermal imaging sensors that detect and take pictures of the thermal signatures of human bodies and other objects have recently been used in thermostats to check facial temperatures to check for COVID-19 at multiple building entrances without contact. Under these circumstances, the smartphone industry is actively considering integrating such sensors as wearable functions to provide the additional function of real-time temperature measurement. In addition, applying such technology to autonomous vehicles can enable safer autonomous driving.
A research team led by Dr. Won Jun Choi at the Center for Opto-Electronic Materials and Devices of the Korea Institute of Science and Technology (KIST) announced the development of a thermal imaging sensor that overcomes the existing price and operational problems – temperature limitations through convergence research with the team of Prof. Jeong Min Baik from Sungkyunkwan University (SKKU). The sensor developed in this thesis can be operated without a cooling device at temperatures of up to 100 ° C and should be more cost-effective than commercially available sensors, which in turn would pave the way for use in smartphones and autonomous vehicles.
In order to be integrated into the hardware of smartphones and autonomous vehicles, sensors must work stably at high temperatures of 85 ° C or 125 ° C without any problems. In order for conventional thermal imaging sensors to meet this criterion, an independent cooling device would be required. However, high-end refrigerators that promise quality cost over two million Korean won; Even such devices do not make the sensor suitable for operation at temperatures up to 85 ° C. Therefore, the conventional thermal imaging sensors have not been applied to these fields.
A joint research team from KIST and SKKU has developed a device with a vanadium dioxide (VO2) -B film that is stable at 100 ° C. This device detects and converts the infrared light generated by heat into electrical signals; This eliminates the need for cooling devices, which make up over 10% of the cost of thermal imaging sensors and consume a lot of electricity. The device was able to obtain the same infrared signals at 100 ° C as at room temperature. In addition, by making and using an infrared absorber that can absorb as much external infrared light as possible, heat signatures have been detected and converted into electrical signals with three times greater sensitivity. Even at 100 ° C, the device shows a response time of around 3 milliseconds, which is around 3-4 times faster than conventional devices. These high response speeds enable the device to take thermal images at 100 frames per second, which is well above the conventional level of 30 to 40 frames per second. This also makes the device interesting for use in autonomous vehicles.
Dr. Choi of KIST said, “Through our work with convergence research in this study, we have developed technology that could dramatically reduce the cost of producing thermal imaging sensors. Our device has superior responsiveness and operating speed compared to more conventional devices. We expect this to accelerate the use of thermal imaging sensors in the military supply, smartphone and autonomous vehicle industries. “
This research was carried out as an institutional R&D project of the KIST, supported by the Ministry of Science and ICT (MSIT), and as a project of the KIST-UNIST Ulsan Center for Convergent Materials. It was in the current issue of “Applied surface science ”(In the top 3.28% of the JCR field).