According to a report by industry research firm TrendForce, Apple’s thinking on folding devices is significantly different from existing manufacturers. It is treating the folding problem as a material science topic and manages stress distribution by redesigning the adhesive layer inside the screen, rather than simply focusing on the hinge structure.
Foldable phones have been on the market for many years, but screen creases have always been an unavoidable core compromise compared with traditional straight-format phones. In the early days, manufacturers mainly used hinges, support plates, and mechanical stretching structures to try to flatten the screen as much as possible when it was opened. These methods improve durability to a certain extent, but they cannot completely eliminate deformation.
TrendForce pointed out that the root cause of the crease lies in the high concentration of stress in the bending area, not just the macro phenomenon of "the screen is folded". With repeated opening and closing, the position of the so-called "neutral layer" inside the display panel will continue to shift, causing strain and microscopic deformation in local areas, eventually evolving into a "broken line" visible to the naked eye. Current complex hinge designs can disperse external forces to a certain extent, but cannot directly control how stress is conducted and released within multi-layer materials.
After multiple generations of product iterations, even with more sophisticated hinge systems, screen creases on foldable devices are still common. Improvements at the hardware level have indeed reduced the degree of creases, but they have not really touched on the essential issue of "how laminated materials respond under repeated stress."
In this context, "Optically Clear Adhesive" (OCA) used to bond display structures has begun to be regarded as a key breakthrough. OCA has always played the role of a transparent adhesive layer, used to firmly bond various layers of display components together. Now engineers are trying to give this glue layer more functions than just "clear glue."
TrendForce reports that the new generation of OCA behaves more like a deformable "flexible cushion": During the normal folding process, the material remains soft, helping to spread stress over a larger area and avoid long-term accumulation at a single folding point. When encountering a momentary impact or large external force, the same material can become stronger locally and provide necessary support in the bending area to maintain the shape of the display structure.
As the device is used over time, OCA will also "displace" slightly on a microscopic scale, filling in subtle unevenness between layers, reducing the scattering of light in the folded area, and making the creases less visually obvious. The current priority of manufacturers is shifting from simply designing hinges to finely regulating the bending, stretching and rebound behavior of each layer of material inside the display module to achieve a panel with more uniform overall stress and avoid stress concentration on a single fold line.
Judging from Apple’s public patent information, the company’s material strategy focuses on variable thickness glass and targeted material matching to better manage stress distribution on the screen. Thinner glass is used in the fold area to improve flexibility, while areas away from the fold line maintain thicker material for increased durability.
This design idea points to the "controllable deformation" of the entire panel, rather than relying entirely on the "hard resistance" of structural strength. Combined with Apple's consistent rhythm of "entering new product categories on a large scale after key technical constraints are significantly alleviated", folding devices seem to be gradually approaching what Apple considers to be a mature window.
If Apple significantly reduces the visibility of creases through material improvements, its strategy of prioritizing durability and consistency on foldable phones may actually lower consumers' psychological expectations for "creases" in the early stages of the market. At the same time, improvements in materials will directly improve the long-term fatigue performance of panels, which has always been a key concern in the lifespan and reliability of folding devices.
Compared to the hinge appearance, which is more easily perceived and marketed by consumers, the most important progress in folding devices is actually happening inside the screen stack structure. With the advancement of adhesive material engineering and stress management technology, the industry is expected to further improve the durability and look and feel of products in daily use while maintaining the folded form, laying the foundation for a new generation of folding devices including the rumored “iPhone Fold”.