Mitsubishi Materials Corporation (President: Hiroshi Yao, Capital: 119.4 billion yen) has led the world in developing a flexible thermistor sensor which functions even when bent and is the thinnest in the world at 100µm or less.
Thermistor sensors detect temperature and are widely used in a variety of technology found in daily life. Examples include electronics such as smartphones and computers, home appliances such as air conditioning, and automobiles.
In recent years, in order to realize even more accurate control for temperature change in electronics, there is strong need for thermistor sensors which are compact, thin and offer high-speed thermal response. Our company is conducting R&D for products which will satisfy these needs.
Conventional thermistor elements are made from oxide materials. It is necessary to fire at high temperatures of 600°C and more. Since thin thermistor is easy to be broken without a supporting substrate, it is normally formed on top of a hard ceramic plate made of material such as alumina. On the other hand, conventional thermistor sensors with protective film and lead wires attached to elements have a minimum thickness of about 500µm. As such, realizing thinner sensors has been an R&D theme.
Our company has developed a flexible thermistor sensor for which has a thin thermistor film of 0.1µm to 0.2µm is formed directly on top of a polyimide film with a thickness of 50µm. The total thickness of sensors including electrodes and protective film is 70µm , making it the world's thinnest thermistor sensor.
Furthermore, although it had been difficult to bend conventional thermistor sensors, we have confirmed the function of our new sensor even when bent to a 6mm radius of curvature. Moreover, thanks to its exceptional thinness, our sensor realizes high-speed thermal response which is approximately 6 times faster than conventional thermistors. We have also confirmed an operation temperature range of -40°C to 200°C, which exceed the conventional range of -40°C to 125°C.
The flexibility and thinness of our thermistor sensor enables installation in small gaps and curved areas of mobile devices, locations where installation had previously been difficult. This enables a variety of design for devices and makes it possible to use the sensor in a broad range of fields.
In the future, in addition to thermistor sensors, our company will continue to utilize our unique technology to develop, manufacture and sell products which contribute to the growth of the information electronics field.
Diagram: 6mm radius of curvature