An overlay surface for a user interface of a device comprises a lower light-diffusing semitransparent layer affixed to an upper transparent layer. Graphics printed on the bottom surface of the transparent layer are protected from wear by the overlying transparent layer, while light sources back-illuminating the graphics from below are diffused by the semitransparent layer before they reach the graphics. The graphics of the surface may be provided by an opaque mask having transparent or translucent cutouts. The multilayer surface enables the graphics to be evenly back-illuminated while at the same time being protected from external wear without the need for additional light-diffusing elements such as light pipes.