Advances in optically clear adhesive (OCA) will be a key factor in Apple’s ability to provide a foldable iPhone with a near-invisible crease in its display, according to TrendForce.
The supply chain intelligence firm outlined the technologies in a new report on foldable display innovation. It also notes that Apple’s patents will contribute to the “crease-free” foldable display.
Creases originate from the misalignment of the neutral layer within the panel stack, which causes localized tensile stress, leading to micro-cracks or permanent deformation under stress concentration. The core solution lies in precise control of stress distribution and neutral layer positioning within the multilayer structure.
In next-generation foldable devices, ultra-thin glass (UTG) is no longer just a surface protection layer. As indicated in Apple’s patents, a variable thickness design combined with chemical strengthening allows the folding area to be locally thinned at the bending axis to improve bendability, while non-folding regions retain greater thickness for impact resistance.
TrendForce says the single most important factor is OCA. No longer limited to a bonding function, OCA now exhibits pronounced viscoelastic properties through optimized modulus design and material composition. It remains soft during gradual bending to reduce fatigue stress, while under sudden external force, its modulus temporarily increases to provide localized structural support.
Apple’s first foldable iPhone is expected to debut alongside Apple’s iPhone 18 Pro lineup in September.
