Dependence of substrate deflection on spacer pitch in emissive flat panel displays

To obtain optimum spacer configurations in the panel for flat panel display application, the stress and deflection distributions in the substrates were calculated by the finite element method. For the panels having different configurations of spacers, such as shape and distance between spacers, the dependence of substrate deflection on these variables were calculated and measured. The spacing of spacers was varied from 5 to 40 mm in the vacuum-sealed panel, where the face and base plates were made of soda lime glasses having thicknesses of 1.1 mm. The results of deflection values in the substrate agree closely between those by the simulation and experimental measurement for the ball-type spacer. Also in comparison of spacers using the bar-type and ball-type, the maximum stress and deflection values are always smaller in the former than the latter. When the spacer pitch is below 15 mm, the maximum substrate deflection is below 5 μm for both types of spacers.