Reliability assurance in foldable displays: Design of experiment-based testing strategy for market-ready products

Abstract

Foldable displays have many moving parts and can operate in different environments. These conditions lead to potential interactions between diverse failure mechanisms and stresses, making reliability assurance a major challenge. Ensuring reliability while considering all these potential failure mechanisms and stresses is very challenging. This paper introduces a method for efficiently evaluating the reliability and lifespan of foldable displays. First, potential failure modes associated with foldable displays were identified, and corresponding influencing factors were determined. In addition to the fundamental stress factor of repetitive folding, temperatures, humidity, and temperature changes were chosen as influencing factors. To assess the influence of these factors on the display performance, two levels of stress severity were selected. Using these three factors and two stress levels, experiments were conducted using the design of experiments (DOE) method. The test results intuitively revealed the principal effects of each stress factor on the final quality and performance of the display. We found that low temperatures and temperature changes can affect the catastrophic failure of the display panel, and the number of folds impacts the degradation of the hinge parts. The proposed DOE-based evaluation method provides an efficient and economical approach for assessing the reliability of foldable displays.