Samsung Electronics and Apple are considering cover glass for foldable displays that is thinner only in the center, for products due in 2028, ZDNet Korea reported on November 4. The two companies are reportedly discussing specifications with their respective suppliers, and nothing has been finalized. The design under consideration varies thickness by location: about 40μm in the central area that bends, and 100μm or more in the peripheral areas that do not.
The component in question is the ultra-thin glass (UTG) that covers the surface of a foldable display. The aim is to secure flexibility in the center while improving protection at the edges. However, thinning the glass in one area is not enough on its own. Challenges remain, including how to handle the recesses created by processing and the boundaries where thickness changes. This approach also serves a different role from the support structure placed beneath the OLED, so improvements to the two should be considered separately.
About 40μm in the center, 100μm or more at the edges
What stands out in this report is the idea of varying thickness between the part that folds and the parts that don't, rather than using the uniform thickness of conventional designs. The center is thinned to about 40μm to prioritize bendability, while the periphery keeps a thickness of 100μm or more. Rather than thinning the whole screen evenly, the design adjusts thickness to the role each area plays.
According to ZDNet Korea, the thicker periphery is also intended to improve surface hardness. However, the 100μm-or-more figure is a specification under discussion, not the result of measuring scratch resistance or drop durability. Likewise, the roughly 40μm center thickness is a value under consideration this time, not a statement of the physical limit of bendable glass. Glass hardness and durability are not determined by thickness alone; they also depend on material composition, strengthening treatments, and the support structure of the display as a whole.
In an August 4 report, ZDNet Korea also introduced a technology called "CTG" that thins only the center by etching. Etching is a processing technique that removes part of a material using chemicals or similar means. In this design, thickness differences would be created by selectively removing material from the center, but the processed surface develops steps and recesses. That makes techniques for finishing the display surface flat just as important as adjusting thickness.
Filling the recesses to make a flat screen
According to the August report, development was moving forward on filling the thinned center with a filler material to even out the surface height, and on bringing the optical properties of the filler close to those of the surrounding glass. The November report also cited filling the removed area and tuning optical properties as challenges. In other words, even if the center of the glass can be made thinner, that alone does not make a finished product. Reflections and the visibility of boundaries where different materials meet must be suppressed so that display quality is not degraded.
One example of a processing technique that can create such thickness differences is the published patent KR20250039870A, filed by Chemtronics. Published on March 21, 2025, it describes a method of forming a thick flat area, a sloped area, and a thin flat area by etching while peeling away a protective film attached to a glass substrate. By adjusting factors such as the peeling speed of the protective film, the shape of the slope connecting the thick and thin areas can be controlled.
The patent also describes an embodiment in which the folding portion is placed at the center of the glass. It also explains that the slope shape in the area where thickness changes relates to light reflection and how visible the boundary is. This shows that simply cutting the glass is not enough; connecting the areas of different thickness smoothly is also important for ensuring display quality.
That said, there is no evidence that this patent will be used in products being considered by Samsung Electronics or Apple. It is only one example of a processing technique that could be used to make partially thinned glass, and the publication of a patent cannot be linked to the establishment of mass-production technology or a decision to adopt it in products. Read together with the reports, what emerges is that, in addition to the process of adjusting glass thickness, the process of smoothing out steps and optical properties after processing is also a key challenge on the way to practical use.
The surface glass and the support structure under the OLED are separate technologies
Glass flexibility and durability depend not only on thickness but also on the properties of the material itself. Glassmaker SCHOTT explains that material composition and chemical strengthening are important for improving the flexibility and strength of ultra-thin glass. A design that varies thickness between the center and the edges concerns which part of the glass to thin, which is a different technical issue from the choice of materials and strengthening methods.
Samsung's "Flex Titanium," officially announced on July 15, 2026, is a structure that places a titanium alloy film and a titanium plate beneath the OLED. According to the company, these components support the display from the inside, balancing thinness with flexibility and strength. It improves a different part from cover glass that is thinned only in the center, and the two are not successor or alternative versions of the same technology.
The parts each technology targets, and their roles, can be summarized as follows.
| Target | Change | Aim / challenge | What can be confirmed now |
|---|---|---|---|
| Surface glass thickness | About 40μm at center, 100μm or more at edges | Balance bendability at the center with protection at the edges | A proposal reported by ZDNet Korea; product specifications not finalized |
| Thickness boundary and filling | Control of slope shape; use of filler in recesses | Flatten the surface; improve reflections and boundary visibility | Chemtronics' published patent is one example of a processing technique; the August report described the state of filling-technology development |
| Glass material | Material composition and chemical strengthening | Improve flexibility and strength | SCHOTT's technical explanation; does not indicate the materials to be used this time |
| Support structure under the OLED | Titanium alloy film and titanium plate | Support the display from the inside | The Flex Titanium configuration announced by Samsung |
These are technical improvements to different parts and processes, and the sources listed in the table do not compare the performance of the same product. For example, strengthening the support structure under the OLED does not necessarily solve the problems related to the filler and optical properties of the surface glass. Nor is it appropriate to regard CTG as a successor or alternative to Flex Titanium. To evaluate the durability of a foldable display, it is necessary to distinguish the role each component plays and what each improvement actually enhances.
What to watch on the way to 2028
The outlook on timing changed between the August and November reports. In August, there were expectations that the technology could be applied as early as 2027, but the November report said specification discussions are underway with an eye toward adoption in 2028. Industry sources also suggested that a final decision on adoption would come between October and December 2027. Products in 2027 are expected to continue using conventional UTG of uniform thickness.
However, these are not product plans formally announced by Samsung Electronics or Apple, but industry sources' outlooks on development trends. It therefore cannot be asserted that the adoption timing has formally been postponed from 2027 to 2028. At this point, the target models and prices are unknown, and no specific measurement results on mass-production yield or durability have been published.
The key question going forward is whether glass with different thicknesses at the center and edges can be turned into a product without sacrificing display quality or durability. In particular, it will be necessary to confirm, along with specific test conditions, how noticeable the boundary between the filler and the glass is and what effects appear after repeated folding. Whether varying the thickness partially actually improves visibility and protection in real products will be important in deciding whether to adopt the design.