The investigation of buckling, deformation and interaction of elastic films for touch panel applications

Thin ITO-based PET conductive membranes are the major sensing structure in resistive touch panels for network phones or other applications. However, device failures or malfunctions such as early touch and disagreement between force-applied and touched locations have been reported. By examining the surface profiles, it was found that these membranes have considerable initial out of plane deformation. This could be a sign of membrane buckling since the clamped design could causing additional in-plane compression which could triggering the structural buckling. It is important to analyze the buckling behavior of ITO/PET membranes due to initial imperfection, residual stress, or assembly issues, for developing engineering solutions for quality assurance. In this work, both finite element analyses and essential experimental characterizations are performed as the first step toward solving this problem. In conjunction with our previous study [1], this work mainly focuses on the buckling behavior by considering the effect of the compliance of double side glues and the associated post-buckling behavior. In parallel, several experimental investigations have been conducted for characterizing material properties of the adhesion tapes and the panel surface profile for supporting the buckling and post buckling analyses. By both simulation and experimental investigations, the major control factor for causing malfunction of touch panel could be identified and the corresponding engineering solutions would be developed for enhancing the device reliabilities.