News Release
June 27, 2022
Aichi Steel Corporation

Success in Technology Development of a Wide-Range
MI Sensor for the Security and Medical Fields-Commencement of sample sales of wide-range MI sensor
with a wider measurement range in high-sensitivity areas -Aichi Steel Corporation (President: Takahiro Fujioka) is working to improve the performanceof the MI sensor *1 to apply its technology to the security and medical fields (Fig. 1) with thetarget year set as 2030. As a part of the company's development results, Aichi Steel has
succeeded in developing technologies for a wide-range MI sensor that can detect weakmagnetic fields even in environments surrounded by magnetic fields far stronger thangeomagnetism. Accordingly, the company has started selling samples *2.
The MI sensor is an extremely highly sensitive magnetic sensor based on the MI effectdiscovered in 1993 by Dr. Kaneo Mohri, a professor emeritus at Nagoya University, which has
been successfully developed and mass-produced through the application of technologies
relating to materials, magnetic properties, and surface treatment that Aichi Steel has been
improving since its founding. We have delivered more than 140 million MI sensors mainly for
use as electronic compasses for mobile phones.
Due to growing demand for detection of weak magnetic fields in the security and medical
fields in recent years, Aichi Steel has been providing Type DH, a product that is even more
highly sensitive than those used in electronic compasses. There was strong demand from themarket to use MI sensors in environments surrounded by strong magnetic fields. To realize
such a technology, however, we needed to develop a magnetic sensor that would provide bothhigh sensitivity and wide measurement range, which was a technologically difficult challenge.
As a result of taking on this challenge, Aichi Steel has successfully developed a wide-range
MI sensor with an extended measurement range by feeding back a part of the MI sensor output
as magnetism to the amorphous wire. In general, two coils, one for taking care of the MI sensor
output and the other for magnetic feedback, are required to implement this technology.
However, we have achieved both high sensitivity and wide measurement range with a single
coil through the new magnetic feedback technology developed by us this time (Fig. 2).
This technology is expected to be applied to situations such as metal detection near an
MRI examination room that generates strong magnetism, detection of mixed foreign
substances in manufacturing lines and use in magnetic security gates.
As an important product that will contribute to the Smart Company’s target sales ofapproximately 60 billion yen in 2030, Aichi Steel will further improve the performance of theMI sensor and aim to contribute to a safe and secure society through our micro magnetism
sensing technology.
*1 For more information on the MI sensor, see the special website. (https://www.aichi-steel.co.jp/ENGLISH/smart/mi/)*2 The product we developed this time will be displayed at Sensors Coverage Expo & Conference 2022 (US) in June,Sensor Expo Japan in September and Electronica 2022 (Germany) in November.

Fig. 1: Technology Development of an MI Sensor with a Wider Measurement Range
in High-Sensitivity AreasFig. 2: Magnetic Feedback Technology that Extends Measurement Range