iPhone Ultra: How to make the display crease invisible Apfelpatient

According to market research firm TrendForce, a special optical adhesive plays a key role in making the iPhone Ultra's display crease virtually invisible. Combined with ultra-thin glass, this creates a multi-layered system that prevents creasing.

For years, the visible crease in the display was the main reason Apple didn't release a foldable iPhone. While Samsung and other manufacturers had already sold several generations of foldables, the crease was considered unacceptable in Cupertino. Now, the problem appears to be largely solved – but the technical solution is more complex than a single breakthrough. TrendForce has now broken down the various innovations that work together to minimize the crease on the iPhone Ultra.

Creases in foldable displays arise from stress imbalances within the multi-layered display structure. With repeated bending, the so-called neutral layers—the planes where there is no tensile or compressive stress—shift relative to each other. This leads to localized material fatigue, microcracks, and permanent deformation. According to previous reports, Apple had to reject numerous prototypes from display partner Samsung before its own designers were actively involved in finding a solution.

Ultra-thin glass with variable thickness

A key component is the ultra-thin glass (UTG), which in Apple's solution serves more than just as a protective layer. According to TrendForce, Apple uses a variable-thickness design: at the bending axis, the glass is locally thinned to increase flexibility, while it remains thicker in non-bending areas to ensure impact resistance. Chemical reinforcement ensures that the thin glass is still sufficiently durable.

This technique is already known from Apple patents and ensures that the display reacts more flexibly at the folding point without sacrificing durability.

The decisive factor: Optical adhesive

According to TrendForce, the real key technology is a special optically clear adhesive (OCA – Optically Clear Adhesive). This adhesive fulfills several functions in foldable displays that go far beyond simply bonding the components.

The OCA exhibits so-called viscoelastic properties: When bent slowly, it remains soft and reduces fatigue stress in the material. Under sudden force – for example, when the device falls to the ground – its modulus of elasticity temporarily increases, thus providing structural support.

Particularly relevant for wrinkle reduction are the adhesive's microflow properties: it remains sufficiently fluid to fill microscopic irregularities in the display that develop over time. These irregularities would otherwise scatter light and be perceived as visible creases. The OCA evens them out, thus minimizing the optical impression of a crease.

Apple aims to capture 20 percent of the foldable market

TrendForce estimates that Apple could capture around 20 percent of the global foldable phone market in its first year. That would be a remarkable entry into a segment currently dominated by Samsung. The September launch of the iPhone Ultra, priced above $2,000, will reveal whether Apple's meticulous attention to detail in the foldable display provides enough compelling reason to establish itself immediately in the premium foldable phone market.

For a complete overview of all previous iPhone Ultra leaks, you'll find a continuously updated summary of all rumors here. (Image: Shutterstock / tinhkhuong)