A fundamental technology to eliminate the “crease,” the biggest drawback of foldable displays, has been developed in South Korea. The crease has been a major obstacle to market expansion due to the nature of foldable displays, which need to be folded and unfolded repeatedly. Global companies like Samsung Electronics and Huawei have attempted various methods to resolve this issue, but they failed to completely remove the crease, affecting consumer satisfaction and market expansion speed. Therefore, the smartphone industry has long considered “realizing a crease-free foldable display” as a crucial technological challenge. The newly developed technology is expected to enhance the completeness of foldable devices in the global market, accelerating their popularization and growth rate.
KAIST announced on the 20th that Professor Pilseung Lee’s research team from the Department of Mechanical Engineering developed the core technology to fundamentally solve the crease issue occurring at the fold area of foldable smartphone displays and has registered it as a patent.
The research team is currently applying for patents in the United States, China, and the European Union (EU) to secure global technological competitiveness.
Until recently, global smartphone companies have invested heavily in research and development to resolve the crease issue. However, they have not succeeded in completely eliminating the crease, which was perceived as the biggest hindrance to the expansion of the foldable smartphone market.
The research team began their research by addressing the inconvenience experienced firsthand when using foldable phones. After dismantling dozens of used foldable phones and conducting various experiments, they derived a solution by innovatively redesigning the “adhesion area” between the display and the support panel.
The core of the redesign is to avoid concentration of deformation in specific folding areas and instead distribute it to surrounding areas. This approach perfectly demonstrated the possibility of achieving a “crease-free foldable” device while ensuring normal smartphone functionality.
For performance verification, when a straight-line LED light was shone on the prototype, the reflected light maintained a clear straight line without distortion. This improved on the problem seen in commercial products, where light is refracted at fold areas, making the line appear bent.
In particular, the prototype showed no visual distortion even under conditions detecting minute bends with crease depths below 0.1mm.
The technology developed by the research team is significant in that it presents a new design paradigm overcoming the limitations faced by the existing industry. Most importantly, it fundamentally suppresses crease formation and minimizes display deformation over tens of thousands of folds, ensuring excellent durability.
The structure is intuitive and simple, allowing easy application to existing manufacturing processes. This advantage makes it applicable across a range of foldable display devices beyond smartphones, such as tablets and laptops, indicating broad industrial applicability.
Industry insiders anticipate that if the technology developed by the research team is commercialized, it is likely to encourage participation from global companies that hesitated to enter the market due to the crease issue. This is expected to enhance consumer satisfaction and accelerate the growth rate of the stagnant foldable market.
Professor Lee stated, “The research team has successfully solved a problem that even global companies couldn’t address with a relatively simple and clear method. We hope this technology spreads across next-generation displays such as smartphones, laptops, and tablets, strengthening Korea’s technological competitiveness.”
Meanwhile, this research was supported by the ‘2022 Daedeok Innopolis Campus Project.’ The core technology patent acquired through the research was registered in September last year.