Inkjet Printing Next-Generation Three-Dimensional Touch Device
The proposed touch two-terminal sensor is poised to revolutionize the field of input device architectures.
Researchers from Yonsei University have developed a groundbreaking 3D touch-sensor device with a simplified, easy-to-produce, cost effective, and durable design.
Photo credits: Sergey Nivens from Shutterstock
Touch-sensitive devices are an integral part of our daily lives. Central to these devices are "crossbar arrays," which are electrical components capable of accurately pinpointing the touch location. It is complicated to design such arrays, often requiring various components such as multiple electrodes, which facilitate the flow of electric current within the device circuit. Therefore, the fabrication and setup of theses devices can be challenging. Is there a simpler alternative to this ubiquitous technology?
Addressing this question, a research team led by Professor Wooyoung Shim from the Department of Materials Science and Engineering at Yonsei University in Korea has now developed a simplified touch-sensor device with only two electrodes. Their work was published in Advanced Materials on 24 August 2023.
The team had initially planned to create a conventional 2D crossbar-type pressure sensor, which would cover a large area and maintain high resolution. Sensitivity over a large area was achieved with an inkjet printer known for its simplicity and affordability. However, ensuring high touch accuracy required placing the electrodes very close together on a thin line, posing a significant challenge. To tackle this issue, the researchers adopted an innovative approach.
They designed a remarkably simple yet ingenious device, featuring only two electrodes. The simplicity of this two-terminal device thus presents an opportunity to potentially revolutionize the production of touch sensors. Prof. Shim emphasizes: “This work has great research value as it does not merely attempt to address technical aspects like thinly printing electrodes over a wide area to achieve the goal, but instead devises a new measurement system itself.”
The actual device fabrication utilizes “time difference measurement” and “gradient electrodes” to enable 3D touch sensitivity, based on resistance change as a function of distance, resistance variation dependent on the electrode composition, and capacitance fluctuation due to changes in the thickness of the dielectric layer in the device. Furthermore, this device also employs transparent electrodes and has shown durability against folding.
This touch-sensor holds promise in various applications spanning a wide domain. It can be used as a low-cost sensor in disposable instruments used to diagnose various diseases. In the long term, this innovation can lead the way for the design of accurate pressure sensors spread over a wide area by overcoming the challenges associated with electrode printing. “Notably, the time difference measurement and gradient electrode concepts are not limited to pressure sensors but are technologies that can be expanded to other areas currently using 2D crossbar arrays,” highlights Prof. Shim.
The device designed by this team thus yields a precise 3D touch sensor with only two terminals, making it easy and low-cost to manufacture, while greatly simplifying the construction of devices with accurate touch sensitivity.
Find out more:
Title of original article: Three-Dimensional Touch Device with Two Terminals
Journal: Advanced Materials
Contact corresponding author: Prof. Wooyoung Shim (email@example.com)
Professor Jong-Hyun Ahn
Professor Seong Chan Jun
Professor Donghyun Kim