70‐3: Research on reliability bulging of carbon fiber bracket based on folding products

Abstract

Carbon fiber bracket can greatly reduce the weight of foldable display modules, making a significant contribution to the lightweight of foldable mobile phones. This article takes OLED display modules as the research object, and fully reveals the bulging mechanism of carbon fiber bracket through disassembly analysis, infrared analysis, SEM analysis of pre impregnated materials, FIB slicing analysis after boiling carbon fiber boards, and verification of process parameters. The results indicate that the bulging delamination interface mainly occurs between FEP adhesive and carbon fiber board, and the fundamental reason is that the carbon fiber board releases gas. Further analysis indicates that carbon fiber board contains a curing agent, which contains a dicyandiamide component. Under high temperature and humidity conditions, dicyandiamide reacts chemically, releasing ammonia gas and damaging the interface between the colloid and carbon fiber board, resulting in delamination between FEP adhesive and carbon fiber board, and bulging in the reliability testing.