The invention relates to A method for a lighting device, in particular for a display device such as a LCD-TV, projector etc., generating radiation including at least visible light for illumination with at least one light-emitting element (1) being a LED (1) or an OLED, emitting radiation comprising an average light intensity for illumination purpose, a controller (2) coupled to the light-emitting element (1) modulating said radiation for a data transfer simultaneously to the illumination purpose, wherein the controller (2) is configured in such a way, that simultaneously data signals are transmitted via the generated radiation of said light-emitting element (1) and said modulation is not visible by an observer, wherein the data signals are transmitted to a detecting unit (3).