Osaka University Develops the Thinnest and Lightest Magnetic Sensor Matrix Sheet System

February 06, 2020 by Luke James

A team of Osaka University researchers have developed a thin and light magnetic sensor matrix sheet system that visualizes the two-dimensional distribution of magnetism on various surfaces.

Current magnetic sensor circuits are built using silicon-based hard electronic elements that are integrated on a substrate with a hardness similar to that of glass. This means that they can only be placed on flat surfaces, otherwise they will break. 

In contrast, flexible and soft magnetic sensors have also been developed, however, there is no device integrating a driving circuit, signal processing circuit, sensor scanning mechanism, and wireless measurement unit in the same place, all of which are needed to create a system like that developed by Osaka University researchers in partnership with the Leibniz Institute for Solid State and Materials Research.


A flexible sensor system.

The imperceptible magnetic sensor matrix system. Image used courtesy of Osaka University.


Improving Sensitivity with the Magnetic Sensor System

According to Masaya Kondo, lead author of the study reporting on work done by Osaka and Leibniz researchers, “Fabricating flexible magnetic sensor elements is difficult, and it’s hard to integrate the fabrication process with circuit technology,”. 

The researchers have been able to develop the world’s thinnest and lightest magnetic sensor matrix sheet system which can visualize the two-dimensional distribution of magnetism on various surfaces. Described as “skin-like”, the system integrates flexible electronic elements (‘organic transistors’) and giant magnetoresistive elements on a 1.5-μm-thick plastic film. The circuit fabricated using this process can then be attached to the skin without causing discomfort and can function even when folded. 

The system’s sensitivity is 10 times higher than conventional systems and is able to not only detect and amplify weak magnetic signals but also visualize the two-dimensional distribution of magnetism by scanning magnetic sensor elements arranged in a matrix pattern.


Graphs and a magnetic mapping of the sensor output of a magnetic sensor matrix system.

An image of magnetic field mapping by using a magnetic sensor matrix system. Image used courtesy of Osaka University.


The Benefit and Use of the Mapping Sensor System

On top of physical information, magnetic information that is obtained is much more precise than electrical information. This is because magnetic sensors have higher spatial resolution due to the high permeability of magnetism in substances. A sheet-type sensor system, therefore, provides highly precise information as it can be applied to many objects regardless of shape.

For example, by attaching the sheet-type sensor system to a reinforced structure, such as a building, the damaged locations could be identified precisely and mapped using the distortion of magnetism caused by deteriorating steel beams and bars. Another potential application is in medicine, where the sensor could be used for more precise cardiac diagnoses where electrocardiography is replaced by magnetic mapping.