US Patent 7294966 Variable thickness EL lamp

An EL panel on a rigid substrate is thinned in selected areas, or overall, to provide a backlight for keypads and other applications that would otherwise require a more flexible panel or additional structure. Lamp materials are deposited on one side of a rigid substrate and then substrate material is ablated with a suitable tool, working from the opposite side of the substrate as the lamp materials. The depth of cut can be constant or variable, enabling one to tailor the flexibility of an area to the desired tactile response for a keypad or to provide clearance in close quarters. The invention is compatible with known process for making an EL panel.