Design of moiré-free metal meshes using ray tracing for touch screen panels

Using a ray tracing technique, we investigate the dependence of the moire effect on the crossing angles between touch screen panels (TSPs) and display panels, the metal grid structures (spacing and width), and metal grid shapes (non-uniform and random grids). Of those design parameters, adjusting the crossing angle (∼45°), reducing the grid width (∼1 μm), and employing a random grid in the shape of irregular hexagon are found to suppress the moire phenomenon to a great extent. We also provide the simulation scheme that can capture the moire patterns observed experimentally and useful design guidelines for metal grids.