Investigation of PDA LCD Screen Failures Under Humidity Cycling and Bending Loads

Abstract

Liquid crystal displays are commonly used in various applications and subjected to numerous environmental and handling conditions that can especially affect the performance and life of these devices. In addition to humidity and temperature exposure, cyclic loadings and handling conditions (bending, repetitive shock, and drop loading) have been shown to cause failures in LCDs. Due to the large number of variable failure modes and use conditions, the question arises: how long can a LCD survive before a failure occurs? Characterizing these failures, along with providing information and techniques to help assess the life expectancy of an LCD are addressed here.

The effects of cyclic humidity exposure and biaxial bending were studied. The resulting failures were analyzed and compared to previous studies to determine common failure modes and relationships that would be useful in providing a rapid product life assessment. Conclusions were made concerning appropriate methodology and testing that can be consistently and efficiently be used to assess LCD assemblies, thus saving time and money in the manufacturing process.