Jan 23 2020
Human skin is an interesting, multifunctional organ. It has exclusive properties that arise from its compliant and flexible nature. It includes lots of receptors interconnected with the nervous system, which enable interaction with the external physical environment.
Flexible electronic skin equipped with an array of giant magneto-resistance sensors and complex electronics circuit designed and developed for sensing distribution of magnetic field. Image Credit: Masaya Kondo.
For a long time, researchers have been making efforts to confer artificial skin with these features, for use in robotic applications. The working of robotic systems is strongly dependent on electronic and magnetic field sensing capabilities needed for positioning and orientation in space. Considerable research and development have gone into the implementation of these capabilities in a compliant and flexible form.
The latest developments in the area of organic electronics and flexible sensors provided essential preconditions. These devices have the ability to function on soft and elastic surfaces. Meanwhile, sensors identify several physical properties and convey them through readout circuits.
However, if natural skin must be closely replicated, it is essential to interconnect a large number of individual sensors. This difficult task proved to be the main obstacle in developing electronic skin. First-ever demonstrations were performed using a series of individual sensors addressed separately. This inevitably led to a huge number of electronic connections.
Researchers had to take a crucial technology step to reduce the necessary wiring. That step was to realize fully integrated devices by combining complex electronic circuits—like amplifiers, shift registers, switches, and current sources—with individual magnetic sensors.
Scientists from Dresden, Chemnitz, and Osaka were able to solve the problem by developing a cutting-edge, active-matrix magnetic sensor system. They have described the system in an article published recently in the Science Advances journal. The sensor system is equipped with a 2 x 4 magnetic sensors array, organic signal amplifiers, and an organic bootstrap shift register that controls the sensor matrix.
The unique aspect is that all electronic components of the system are based on organic thin-film transistors and built inside a single platform. The team has shown that the system exhibits high magnetic sensitivity and has the ability to obtain the two-dimensional magnetic field distribution in real time.
In addition, the system exhibits high strength against mechanical deformation, like kinking, creasing, or bending. Apart from the complete integration of the system, the use of organic bootstrap shift registers is a highly crucial development step that could help realize active matrix electronic skin for wearable and robotic applications.
Elaborating about the next steps of the research, Prof. Dr Oliver G. Schmidt, Director at the Leibniz Institute for Solid State and Materials Research Dresden, and Dr Daniil Karnaushenko stated, “Our first integrated magnetic functionalities prove that thin-film flexible magnetic sensors can be integrated within complex organic circuits.”
The researchers continued, “Ultra-compliant and flexible nature of these devices is indispensable feature for modern and future applications such as soft-robotics, implants and prosthetics. The next step is to increase the number of sensors per surface area as well as to expand the electronic skin to fit larger surfaces.”