Thermal imaging sensors, which detect and record the temperature of the human body, have recently begun to be used in thermostats to check the temperature without contact.
Under these conditions, the smartphone industry is actively looking into the possibility of including such sensors portable in order to obtain an additional function of real-time temperature measurement.
A research team led by Dr. Won Jung Choi of the Center for Optoelectronic Materials and Devices at the Korea Institute of Science and Technology (KIST) has developed a thermal imaging sensor that can operate at temperatures up to 100 ° C without a cooling device: times lower than analogs, so it can be massively used in smartphones and autonomous vehicles.
To integrate with the equipment of smartphones and autonomous vehicles, the sensors must operate stably at high temperatures: 85 ° C and 125 ° C, respectively. In order for conventional thermal imaging sensors to meet this criterion, they need an independent cooling unit. However, high-quality cooling devices are expensive and also do not make the sensor suitable for temperatures up to 85 ° C. Therefore, the usual method does not work.
In new work, the authors have created a device based on a vanadium dioxide (VO2) -B film, which is stable at 100 ° C. This device detects and converts infrared light generated by heat into electrical signals; this eliminates the need for cooling devices, which account for more than 10% of the cost of thermal imaging sensors.
The device was able to receive the same level of infrared signals at 100 ° C as at room temperature. In addition, thermal signatures were detected with three times the sensitivity. The device operates with a response of 3 milliseconds, which is 3-4 times faster than usual. These fast response rates allow the device to capture thermal images at 100 frames per second, well above the typical 30-40 frames per second.