The KAIST research team created a new structure that reduces foldable display creases. This technology does not attach the display and support plate completely, and instead attaches only the edges. The team explained that this helps keep force from concentrating too much in the middle folding area. In tests, almost no creases appeared even after folding the screen tens of thousands of times. They also said the structure is fairly simple, so it is easy to apply to existing manufacturing processes. The team believes it can be used not only for smartphones but also for large-screen devices like tablets and laptops. They have also filed domestic and overseas patents, raising the possibility of commercialization. This study got attention because it solved the crease problem, known as a major weakness of foldable devices, through structural design.
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Why did one crease become such big news
From the outside, it just looks like one line in the middle of the screen. But in foldables, that line almost works like a symbol of how complete the technology is. If the crease looks deep, even an expensive device can feel unfinished, and if you can feel the folding spot every time you swipe with your finger, you start to worry about durability too.
This is why the KAIST study is getting attention. Until now, the industry tried to reduce creases by changing the shape of the hinge, or by improving ultra-thin glass, UTG(a very thin glass layer). But this time, the key difference is that the focus is not on 'how it folds' but on 'what parts are attached and what parts are attached less'.
In other words, they looked at the problem not as user habit or simple repeated fatigue, but as structural stress. To put it simply, the force that the whole screen should share was gathering on the center fold line, creating the crease, so the idea was to redesign the path of that force. If this is right, it means the foldable challenge was not just a hinge problem, but a problem of the whole layered structure.
A crease is not just a looks issue. It is a sign that shows the completeness and reliability of a foldable.
The key point of this study is that it tried to solve the problem by changing the adhesive structure, not the hinge.
Foldables started folding from 2018, but the crease kept staying
The history of foldables is the history of a 'folding screen,' but at the same time, it is also the history of 'how to make the center crease less visible.'
2018: First, a folding screen appeared
Early products like the Royole FlexPai were shocking just because 'the screen folds.' But at that time, proving the possibility came before perfection, and the crease problem was also shown almost as it was.
2019: Galaxy Fold showed the crease to the public
Samsung's first Galaxy Fold seriously opened the foldable era, but at the same time, it also showed that the center crease(folding mark) was a weakness consumers noticed right away. With the protective layer problem and hinge gap issues happening together, the crease became a symbol of 'technology that is still not fully finished.'
2020~2022: They started improving glass and hinges together
The industry expanded the use of UTG and kept adjusting the support plate, protective layer, and hinge structure. The screen looked stronger and flatter, but because the glass, plastic, and adhesive layers all had to move together, stress control became an even more delicate challenge.
2023: Waterdrop hinges became the main trend
Waterdrop or teardrop hinges make the folding radius larger, so the center does not bend too sharply. Simply put, instead of folding paper exactly in half, it feels more like rolling it in a round shape before folding, which reduces stress from gathering on one line.
2025~2026: Now they are looking at adhesive layers and layered structures too
Recently, more people think that just improving the hinge has limits. It has moved to a competition to redesign the actual 'path the force takes' by also adjusting adhesive layers like OCA (optically clear adhesive), support plates, and even the neutral plane design of the stack. KAIST research is right in this trend too.
If you look closely at why wrinkles appear on foldable screens
| Factor | What it means | Why it makes wrinkles worse |
|---|---|---|
| Small folding radius | A structure where the screen bends sharply with a tight curve | Force gathers in a very short section, so the center mark can get deeper more easily |
| Difference in stacked materials | UTG, polymer, adhesive layers, and support plates each stretch and bend differently | Even when they fold together, they do not deform at the same speed, so stress builds up between the layers |
| Wide-area bonding | A method that widely bonds several layers with OCA and ties them together like one body | It is good for stability, but it reduces freedom at the center folding area, so force can concentrate in one place |
| Support plate structure | The design of the layer that supports the shape from behind the screen | If the support plate is too stiff or movement is limited, the fold line can stand out more |
| Repeated folding fatigue | A usage environment where the same spot is folded and unfolded tens of thousands of times | If the tiny deformation that appears first keeps building up, it can grow into visible wrinkles and a different feel to the touch |
What is different between the usual full-surface bonding and the KAIST-style edge bonding
| Comparison item | Usual full-surface bonding | Edge bonding and flexible center structure |
|---|---|---|
| Basic concept | Secure stability and optical quality by widely bonding the overall stack | It supports mainly around the edges and lets the center move more freely |
| Constraint at the folding center | Relatively large | Relatively small |
| Stress distribution | A peak tends to form on the center line | A design that spreads it over a wider area to reduce local concentration |
| Screen feel | Wrinkle reflection and a strange fingertip feel can easily remain | May reduce wrinkle visibility and touch differences |
| Risk | Limit in suppressing wrinkles | In actual mass production, integration checks with the touch layer, cover window, and hinge are needed |
Why does it wrinkle less if the middle is attached less?
The key here is stress distribution. It sounds hard, but the meaning is simple. The force does not disappear. It just does not gather at one point and spreads through a wider path. When the screen folds, instead of the center line taking all the load alone, the areas around it share the load together.
Think of it like this. If cars all crowd into a road with only one lane, traffic gets very bad. But if more lanes open on the side, the same number of cars can move with less traffic. A foldable screen is similar. If the old structure was like 'a road where force crowds into one center lane,' then the edge-bonding structure makes 'a road where force splits into several lanes.'
A wrinkle is usually explained as buckling (when something bends suddenly after being pressed), when a thin film cannot handle compression and starts to ripple. So if compressive stress gathers at the center beyond the critical point, the screen can bend a little, and if that happens again and again, it can become a visible wrinkle. This design is best understood as an approach that tries to make it harder to go past that 'critical point.'
Fixing wrinkles is not really a technology that removes force. It is closer to a technology that redraws the path the force takes.
There are numbers like this between lab success and product launch
The number of folding tests is not an absolute warranty. It is a number that shows the lower limit of basic reliability.
Commercialization does not end just because the technology is good
| Factor | Why it matters | Problems you face in real life |
|---|---|---|
| Durability testing | It can be released only if it can withstand repeated folding, impact, temperature, and humidity | Lab numbers do not fully guarantee the real user environment |
| Manufacturing process | Even a small problem in hinge alignment, layer precision, or bonding quality can cause defects | Even if the technology is good, if the yield rate is low, the cost goes up too much |
| Patents | They are needed for technology protection, license negotiation power, and keeping competitors in check | Filing alone is not enough, actual registration and the scope of rights are important |
| Component integration | Even if the panel is good, if it does not fit with the touch layer, cover window, and hinge, the product quality becomes lower | The best value for each separate technology may be different from the best value for the whole product |
Why is the foldable market taking a short pause now
This is based on the Counterpoint forecast. In 2024, it is the actual growth rate, and in 2025~2026, they are forecast values, so even if they are on the same line, the meaning is a little different.
Why it needs to go beyond smartphones to tablets and laptops
| Device | Value for consumers | Why solving the crease is becoming more important |
|---|---|---|
| Smartphone | The experience of carrying a screen bigger than a premium phone in your pocket | On a small screen, the crease is annoying too, but there are still some buyers who can accept it for now. |
| Tablet | The value of reducing videos, documents, and multitasking into one device | When opened, the bigger the screen gets, the more noticeable the center line becomes, and it also affects the writing experience. |
| Laptop | The possibility of a new form factor that gives both portability and productivity | If creases and reflection distortion remain on a large screen, it becomes less convincing as a work device. |
So this is why this research really matters
We cannot say for sure that this research will remove creases from all foldable phones as soon as next year. For lab results to become real products, they still have to pass many more folding tests, mass production checks, and integration tests with other parts. But the important point is that it showed a clue for solving the problem in a different way, which the industry has been struggling with for a long time.
Looking a little bigger, foldables are now standing between a 'cool device' and a 'really comfortable device.' The price is high, durability still feels uncertain, and the app experience is not completely smooth yet. In this situation, if the crease also looks very visible, buyers will not open their wallet easily. So improving the crease is more than just making the screen pretty. It is closer to a condition for market growth.
If this innovation in adhesive structure really leads to mass production, foldables may become more than products competing only inside the smartphone market. They could become devices that shake the boundary with tablets and laptops too. In the end, the point of this news is not just 'will one line disappear,' but that we have moved one step closer to the question, can foldable screens finally become normal everyday tools.
The core of the crease problem is not just one hinge, but stress control across the whole layered structure.
This research matters because even if the road to commercialization is long, it changed the direction of the solution.
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