73.3:Invited Paper: Four Point Bending of AMLCD Panel

The four-point bend test is used extensively to measure the edge (and surface) strength of AMLCD displays both in panel form and single substrate. The subtleties of four-point bend test for AMLCD panel applications and how one might use additional techniques, such as strain gage, finite element modeling and failure mode analysis, to better understand the data generated are investigated. This paper attempts to show the following: i) the standard four-point bend equation (figure 1) is not applicable to thin AMLCD panels, ii) the edges and surface experience different stress, iii) stresses can be quantified by knowing break location and the appropriate strain level, and iv) failure mode analysis can support the strain analysis and provide valuable information to the experimenter.