Korea develops full-screen fingerprint scanning technology with FBI-levels of security
According to the Daily Mail reported on July 3, the design of modern smartphones has gradually turned to the full screen, but the problem with this design is how to place a fingerprint scanner on the mobile phone. On the full-screen iPhone X, Apple completely abandoned the scanner and switched to its face recognition solution, FaceID. At the same time, competitors add mobile phones to move the fingerprint sensor to the back of the phone.
Researchers now offer mobile phone manufacturers an ideal solution thanks to a new technology that turns the entire display into a huge sensor. They said the findings match the fingerprinting criteria set by the FBI, and the technology may give in the next 12 months.
Experts from the Ulsan National Institute of Science and Technology in Korea have developed a transparent sensor that can simultaneously detect real pressure and skin temperature. Researchers say the ability to identify heat and stress ensures a safer system.
The secret of ultra-thin design is the creation of new transparent electrodes based on a network of interconnected ultra-long silver nanofibers and fine silver nanowires. These components are tiny, and once embedded in the display, they are almost invisible and can simultaneously maintain enough power to scan the user’s fingerprint for authentication.
Dr Jang-Ung Park, who participated in the study, said in an interview: “As people begin to seek borderless phones with a maximised screen size, they can’t find a spot for the fingerprint sensor that usually sits within the home button of a phone. We developed “transparent” fingerprint sensors, aiming to detect a fingerprint placed anywhere on the display of a phone. Our transparent fingerprint sensors achieved the resolution criteria set by the FBI.“
Human fingerprints consist of unique ridges and valleys. One way to detect fingerprints is to sense the change in charge, which is caused by the gap between the peak and the valley. However, traditional transparent materials—indium tin oxide (ITO) used to make touch-sensitive modern smartphone screens are not up to the task. The resistance of ITO is too massive to detect small changes in the charge required by the fingerprint sensor.
The team solved this problem by combining fine silver nanowires that have excellent transparency and silver fibres that have lower resistance. The researchers say the configuration is 17 times more sensitive to charge changes than ITO.
This flexible array is also extremely resistant to bending, making it extremely wear-resistant for applications such as smartphones and tablets.
