A light guide for lighting keys of a keypad in handheld devices. The light guide includes a film and a light emitting diode optically coupled to it. The film provides for substantial total internal reflection of light. A surface of the film opposite the keys includes a plurality of discrete areas, and each of the areas has one or more microstructured features such that each of them extract from the film a substantial amount of light incident upon them by reflecting and redirecting the light such that it impinges upon the film beyond the critical angle for total internal reflection. The microstructured features in each of the areas are adjusted such that they obtain substantially uniform extraction of light from the light source. The light guide can provide sufficient illumination of the keys using only a single light emitting diode as the light source.