{"id":4549,"date":"2026-03-23T08:57:57","date_gmt":"2026-03-23T08:57:57","guid":{"rendered":"https:\/\/saiweiglass.com\/?p=4549"},"modified":"2026-03-23T09:02:34","modified_gmt":"2026-03-23T09:02:34","slug":"foldable-glass","status":"publish","type":"post","link":"https:\/\/saiweiglass.com\/es\/blog\/foldable-glass\/","title":{"rendered":"C\u00f3mo cambi\u00f3 el vidrio plegable los tel\u00e9fonos inteligentes \u00ab Samsung UTG, Corning y SCHOTT comparados"},"content":{"rendered":"
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Quick Specs<\/h3>\n\n\n\n\n\n\n\n\n
Material<\/td>\nUltra-thin glass (UTG), chemically strengthened<\/td>\n<\/tr>\n
Thickness Range<\/td>\n25 \u2013 100 \u00b5m (foldable applications)<\/td>\n<\/tr>\n
Minimum Bend Radius<\/td>\n<1 mm (SCHOTT UTG after processing)<\/td>\n<\/tr>\n
Fold Endurance<\/td>\n200,000 \u2013 300,000+ cycles<\/td>\n<\/tr>\n
Key Suppliers<\/td>\nSamsung Display, SCHOTT AG, Corning Inc., Nippon Electric Glass<\/td>\n<\/tr>\n
Optical Transmittance<\/td>\n91 \u2013 92% (visible spectrum)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Every foldable phone sold today faces the same engineering tension: make the display glass thin enough to bend without snapping, yet strong enough to survive drops and daily pocket friction. Three companies \u2014 Samsung Display, Corning Incorporated, and SCHOTT AG \u2014 have taken fundamentally different paths to solving that problem. Below, we break down their ultra-thin glass<\/a> technologies side by side, using published specifications and real device data rather than marketing claims.<\/p>\n

What Is Foldable Glass and How Does Bendable Glass Work?<\/h2>\n

\"What<\/p>\n

Foldable glass is ultra-thin glass \u2014 typically between 25 and 100 micrometers thick \u2014 that bends repeatedly without cracking. At that thickness range, a sheet of ultra-thin bendable glass behaves more like a flexible polymer film than the rigid panels in conventional smartphones. A 2026 study published in the Journal of the American Ceramic Society<\/a> concluded that ultra-thin flexible glass with reduced Young’s modulus can achieve the mechanical compliance needed for foldable display applications while retaining the optical and surface properties that separate glass from plastic.<\/p>\n

Behind bendable glass technology sits one principle: surface stress. When a sheet of glass bends, the outer surface stretches under tension while the inner surface compresses. Cracks start on the tension side.<\/p>\n

The thinner the glass, the less strain the outer surface experiences at any given bend radius \u2014 which is why a 30 \u00b5m piece of glass can fold flat while a 500 \u00b5m piece shatters.<\/p>\n

But thickness alone does not explain foldable glass durability. Manufacturers reinforce ultra-thin glass through chemical strengthening, an ion-exchange process that can transform the material’s surface properties \u2014 the glass is immersed in a molten potassium nitrate (KNO\u2083) bath at approximately 410\u00b0C. During this process, smaller sodium ions (Na\u207a) in the glass surface are replaced by larger potassium ions (K\u207a), creating a compressive stress layer.<\/p>\n

Research published by the Korean Ceramic Society<\/a> shows this process generates peak compressive stresses between 300 and 2,000 MPa \u2014 enough to withstand crack propagation during repeated folding cycles.<\/p>\n

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\ud83d\udcd0 Engineering Note<\/strong><\/p>\n

Critical relationship: bend radius (R) = thickness (t) \/ (2 \u00d7 surface strain). For a 30 \u00b5m glass with a maximum allowable surface strain of 0.5%, the theoretical minimum bend radius is 3 mm. Chemical strengthening shifts the neutral axis, allowing radii below 1 mm after processing \u2014 per SCHOTT published specifications.<\/p>\n<\/div>\n

Samsung UTG vs Corning vs SCHOTT \u2014 Specs at a Glance<\/h2>\n

\"Samsung<\/p>\n

 <\/p>\n

Three distinct approaches dominate the foldable glass market. Samsung Display was the first to commercialize UTG glass for consumer foldable devices. SCHOTT holds the Guinness World Record for producing the thinnest glass on Earth. And Corning Incorporated \u2014 the company behind Gorilla Glass \u2014 is developing a variable thickness glass with its own ion-exchange strengthening process. Here is how their published specifications compare.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
Specification<\/th>\nSamsung Display UTG<\/th>\nSCHOTT UTG<\/th>\nCorning Bendable Glass<\/th>\n<\/tr>\n<\/thead>\n
Thickness<\/td>\n30 \u00b5m (Gen 1) \u2192 50 \u00b5m (Gen 2)<\/td>\n25 \u2013 210 \u00b5m range<\/td>\nVariable thickness (proprietary)<\/td>\n<\/tr>\n
Bend Radius<\/td>\n\u22641.5 mm (Galaxy Z Fold series)<\/td>\n<1 mm after processing<\/td>\n<3 mm (developmental target)<\/td>\n<\/tr>\n
Fold Endurance<\/td>\n>200,000 cycles<\/td>\n>300,000 cycles<\/td>\n>200,000 cycles<\/td>\n<\/tr>\n
Strengthening<\/td>\nProprietary ion injection<\/td>\nChemical ion exchange (4-10\u00d7 edge strength)<\/td>\nPatented ion-exchange process<\/td>\n<\/tr>\n
Manufacturing<\/td>\nIn-house Samsung Display<\/td>\nDown-draw process<\/td>\nFusion draw ($200M+ per machine)<\/td>\n<\/tr>\n
Key Product Line<\/td>\nSamsung UTG (proprietary)<\/td>\nXensation Flex \/ AS 87 neo<\/td>\nGorilla Glass Ceramic 3<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
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\ud83d\udca1<\/span> Pro Tip<\/strong><\/div>\n

Specs alone do not determine which glass performs best in your hand. Samsung’s UTG benefits from vertical integration \u2014 the same company designs the display, the glass, and the hinge mechanism. SCHOTT sells standalone glass substrates to multiple OEMs, giving device manufacturers more flexibility in display stack design.<\/p>\n<\/div>\n

Bend Radius, Thickness, and Fold Endurance<\/h2>\n

\"Bend<\/p>\n

 <\/p>\n

Three numbers define ultra thin glass performance in foldable devices: bend radius, thickness, and fold endurance. These parameters are interdependent \u2014 changing one forces trade-offs in the others.<\/p>\n

Samsung’s decision to increase UTG thickness from 30 \u00b5m to 50 \u00b5m between the Galaxy Z Flip 5 and Z Flip 6 illustrates this trade-off. Thicker glass means a slightly larger bend radius and more visible crease \u2014 but it also means better drop resistance and reduced screen deformation over time. Android Headlines<\/a> reported that the thicker UTG panel in the Z Flip 6 makes the screen harder and more scratch-resistant while reducing the display crease at the center.<\/p>\n

SCHOTT claims the tightest achievable bend radius in the industry: less than 1 mm after chemical strengthening. That figure comes from their Xensation Flex product line, where the glass thickness can be tuned from 25 to 210 \u00b5m depending on the device manufacturer’s requirements. Their published fold endurance of 300,000+ cycles exceeds Samsung’s 200,000+ figure \u2014 though the two companies may use different testing protocols, making direct comparison difficult.<\/p>\n

\n\n\n\n\n\n\n\n\n
Parameter<\/th>\n30 \u00b5m UTG (Gen 1)<\/th>\n50 \u00b5m UTG (Gen 2)<\/th>\nImpact on User Experience<\/th>\n<\/tr>\n<\/thead>\n
Bend Radius<\/td>\n\u22641.0 mm<\/td>\n\u22641.5 mm<\/td>\nSlightly larger fold gap<\/td>\n<\/tr>\n
Crease Visibility<\/td>\nMore pronounced<\/td>\n20% less visible<\/td>\nNoticeable improvement<\/td>\n<\/tr>\n
Scratch Resistance<\/td>\nLower<\/td>\nHigher<\/td>\nFewer micro-scratches in daily use<\/td>\n<\/tr>\n
Drop Survivability<\/td>\nLower<\/td>\nHigher<\/td>\nBetter accidental drop protection<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Looking ahead, TrendForce reports<\/a> that Samsung is developing a dual-UTG structure for the Galaxy Z Fold 8. By layering two sheets of ultra-thin glass with different properties, Samsung aims to reduce crease visibility by another 20% compared to the Z Fold 7 while maintaining fold endurance above 200,000 cycles.<\/p>\n

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\u26a0\ufe0f<\/span> Common Misconception<\/strong><\/div>\n

Many buyers assume thinner glass always means a better foldable display. In reality, the opposite holds true \u2014 Samsung deliberately moved to thicker UTG because 50 \u00b5m glass delivers meaningfully better scratch resistance, crease reduction, and drop durability compared to the original 30 \u00b5m panels. Optimal thickness depends on the hinge mechanism, not the glass alone.<\/p>\n<\/div>\n

Scratch Resistance and Surface Hardness<\/h2>\n

\"Scratch<\/p>\n

Scratch resistance is the single most common complaint from foldable phone owners \u2014 and the cause is often misunderstood. Scratches users see on their foldable screen typically come from the soft protective film layered on top of the cover glass, not from the glass itself.<\/p>\n

Chemically strengthened ultra-thin glass reaches a Mohs hardness of 6 to 7, comparable to standard smartphone glass. However, foldable phone manufacturers apply a thin polymer protective layer \u2014 usually thermoplastic polyurethane (TPU) or colorless polyimide (CPI) \u2014 over the UTG to absorb impact and prevent glass fracture.<\/p>\n

That protective film has a pencil hardness of roughly 2H, corresponding to a Mohs rating of just 2 to 3. As The Verge explained in their Z Flip teardown<\/a>, the glass underneath is genuinely scratch resistant \u2014 but the film on top scratches as easily as any plastic surface.<\/p>\n

\n\n\n\n\n\n\n\n
Surface Layer<\/th>\nPencil Hardness<\/th>\nMohs Scale<\/th>\nScratch Source<\/th>\n<\/tr>\n<\/thead>\n
UTG (chemically strengthened)<\/td>\n6H \u2013 7H<\/td>\n6 \u2013 7<\/td>\nSand, quartz, hardened steel<\/td>\n<\/tr>\n
TPU protective film<\/td>\n2H<\/td>\n2 \u2013 3<\/td>\nFingernails, coins, keys<\/td>\n<\/tr>\n
CPI (colorless polyimide)<\/td>\n2H \u2013 3H<\/td>\n2 \u2013 3<\/td>\nFingernails, coins, keys<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

SCHOTT’s chemical strengthening increases edge strength by 4 to 10 times depending on glass composition and processing parameters. Samsung uses a proprietary intensifying process that injects a hardening material into the UTG to achieve consistent hardness throughout the sheet. Both approaches target the same goal: make the glass durable enough that the protective polymer layer becomes the weakest link \u2014 and eventually, unnecessary.<\/p>\n

How Foldable Glass Is Manufactured<\/h2>\n

\"How<\/p>\n

Producing glass thinner than a human hair requires a manufacturing process so precise that only a handful of facilities worldwide can achieve it. Two primary production methods \u2014 down-draw and fusion draw \u2014 each have distinct advantages for foldable screen technology.<\/p>\n

Down-Draw Process (SCHOTT)<\/h3>\n

SCHOTT uses a down-draw process where molten glass flows vertically downward through a forming zone, creating a continuous ribbon. Precise temperature control and draw speed determine the final thickness. SCHOTT’s method produces glass ribbons from 25 to 210 \u00b5m and can be adapted for rollable reel-to-reel processing \u2014 where the glass is wound onto spools like film, enabling high-volume manufacturing.<\/p>\n

Fusion Draw Process (Corning)<\/h3>\n

Corning’s fusion draw process feeds molten glass over a V-shaped trough, where two streams flow down opposite sides and fuse at the bottom. Because the surfaces never contact equipment, the resulting glass needs no polishing \u2014 a critical advantage for optical clarity. According to industry reporting, each fusion draw machine costs upward of $200 million, which helps explain why this innovation has been slower to reach consumer electronics at scale.<\/p>\n

Chemical Strengthening: The Final Step<\/h3>\n

Regardless of the forming method, all foldable glass undergoes chemical strengthening. A standard process involves immersing the glass in a molten potassium nitrate (KNO\u2083) bath at approximately 410\u00b0C for 4 to 16 hours. During this ion-exchange process, smaller sodium ions in the glass surface swap with larger potassium ions from the salt bath, creating a compressive stress layer on the glass surface \u2014 with published values between 300 and 2,000 MPa depending on glass composition and processing time.<\/p>\n

Research from the Korean Ceramic Society<\/a> notes that spray-based KNO\u2083 application is emerging as an alternative for ultra-thin sheets, since the traditional dipping method can damage glass below 50 \u00b5m due to solution resistance.<\/p>\n

\n

\ud83d\udcd0 Engineering Note<\/strong><\/p>\n

Production yield for sub-100 \u00b5m glass remains below 60% industry-wide due to breakage during forming and handling. Yield challenges are a primary cost driver \u2014 and why ultra-thin glass manufacturing<\/a> demands far more specialized equipment and intensive QC than conventional flat glass production.<\/p>\n<\/div>\n

Which Phones Use Each Type of Foldable Glass?<\/h2>\n

\"Which<\/p>\n

Samsung’s monopoly no longer exists among foldables in the phone market \u2014 the UTG supply chain reflects that shift. Multiple glass suppliers now compete for OEM contracts, with each device manufacturer exploring different device designs, glass sources, and thickness targets.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n
Device<\/th>\nGlass Supplier<\/th>\nUTG Thickness<\/th>\nYear<\/th>\n<\/tr>\n<\/thead>\n
Samsung Galaxy Z Flip<\/td>\nSamsung Display<\/td>\n30 \u00b5m<\/td>\n2020<\/td>\n<\/tr>\n
Samsung Galaxy Z Fold 3<\/td>\nSCHOTT (all UTG)<\/td>\n30 \u00b5m<\/td>\n2021<\/td>\n<\/tr>\n
Xiaomi MIX Fold 2<\/td>\nSCHOTT (Xensation Flex)<\/td>\n30 \u00b5m<\/td>\n2022<\/td>\n<\/tr>\n
Samsung Galaxy Z Flip 6<\/td>\nSamsung Display<\/td>\n50 \u00b5m<\/td>\n2024<\/td>\n<\/tr>\n
Oppo Find N5<\/td>\nBOE (customized UTG)<\/td>\nNot disclosed<\/td>\n2025<\/td>\n<\/tr>\n
Xiaomi MIX Flip 2<\/td>\nNippon Electric Glass (Dinorex UTG)<\/td>\nNot disclosed<\/td>\n2025<\/td>\n<\/tr>\n
Samsung Galaxy Z Fold 7<\/td>\nSamsung Display<\/td>\n50 \u00b5m<\/td>\n2025<\/td>\n<\/tr>\n
Apple Foldable iPhone (expected)<\/td>\nSamsung Display (reported)<\/td>\nTBD<\/td>\n2026<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

One surprise in this supply chain: Samsung does not always use its own glass. Korean industry publication THE ELEC reported<\/a> that SCHOTT supplied all the UTG for the Galaxy Z Fold 3 in 2021. Meanwhile, Nippon Electric Glass entered the market in 2025 with Dinorex UTG \u2014 adding a fourth major supplier and giving OEMs like Xiaomi more sourcing options for their foldable device designs.<\/p>\n

Apple’s anticipated foldable iPhone, widely reported for a September 2026 launch, is expected to use Samsung Display’s screen technology with ultra-thin glass. According to MacRumors<\/a>, Apple is testing ultra-thin flexible glass panels with uneven thickness \u2014 thinner in the fold zone for flexibility, thicker elsewhere for rigidity \u2014 aiming to make the display crease invisible.<\/p>\n

Foldable Glass vs Plastic Displays \u2014 Why Glass Wins<\/h2>\n

\"Foldable<\/p>\n

Before UTG became commercially viable, every foldable phone used colorless polyimide (CPI) as its display cover. Earlier models \u2014 the original Galaxy Fold (2019) and Motorola Razr (2019) \u2014 both relied on plastic. Switching to real glass solved several problems but introduced new constraints that continue to transform the foldable display industry.<\/p>\n

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\u2714 UTG Advantages Over Plastic<\/strong><\/p>\n