P‐15.24: a Vision‐based Wrinkle Characterization Method for Flexible OLED Screens

Abstract

Folding screen phones have a larger display area compared to the traditional form of full‐screen phones, providing users with more usage scenarios. However, as the number of folding times increases, the functional layer of the display module will creep and wrinkles will appear on the surface of the folded screen, affecting the display effect of the screen. Current academic research has made progress in the mechanical simulation of folded screens, and surface flatness and contour curvature are used as quantitative characterization methods for simulation calculations. This paper proposes a quantitative characterization method of optical wrinkling for simulation results based on the basic theory of machine vision, by projecting a circular light spot at an angle of 45° to the screen onto the surface of the flexible screen, and observing the degree of aberration of the light spot at an angle of 135° to the screen as a failure criterion. The corresponding spot aberration value is calculated based on the coordinates of the grating, the coordinates of the light source and the position of the observation camera after CAE(Computer Aided Engineering) simulation. After comparing the experimental results with the simulation results, it is found that the simulation agrees well with the experiment. Finally, the two stacked structures of PET(polyethylene glycol terephthalate) and CPI(Colorless Polyimide), which are the covering layers of the screen, are taken as examples to illustrate that the present method can provide relevant clues for the structural design of the OLED(Organic Light‐Emitting Diode) screen, the selection of materials, and the mechanical problems in the bending process.