The researchers have developed a sensor sheet with a wide measurement range and high-sensitivity temperature detectors arranged on a film surface. The sheet was fabricated using printing technology in all processes, and large-area and low-cost fabrication can also be possible.

There is increasing focus on temperature measurement of the interior of sealed containers and objects hidden on the back of other objects. Previously developed temperature distribution sensor sheets had temperature detectors arranged on the surface of a thin plate, but measurable temperature ranges were narrow and there were also issues with measurement accuracy. Therefore, development of a flexible sensor sheet capable of measuring wide temperature distributions with high precision was demanded.

The developed sensor sheet consists of X electrode lines, Y electrode lines, insulating films, and printed thermistors. An ink material with an electrical resistance that changes significantly relative to temperature was developed for the temperature-sensitive printed thermistors, and an ink material that exhibits stable electrical resistance relative to temperature changes was developed for the electrode lines. This expanded the measurable temperature range up to 140°C, which is twice that of previous sheets, and achieved measurement accuracy of ±1°C, which is sufficient for practical application. The measurable temperature difference is 0.3°C, which enabled obtainment of high-definition temperature distributions.

The researchers aim at practical application of the developed technology by promoting widespread collaboration with companies.