A light emitting head for use in copiers or printers, the light emitting head having an illuminated length, e.g. a print width or copy width, and including a rigid carrier structure provided from a bulk material that spans at least the illuminated length of the head, the bulk material having a coefficient of thermal conduction larger than 100 W/mK and a coefficient of thermal expansion; a plurality of blocks of light elements arranged in a longitudinal array, the blocks having a coefficient of thermal expansion, each of the blocks of light elements having a first and a second surface, each of the blocks of light elements including a plurality of light-emitting elements exposed on a first surface on the block, the plurality of blocks being physically attached to the carrier structure by a conductive adhesive at substantially the second surfaces, and wherein the bulk material has a coefficient of thermal expansion that differs from the thermal expansion coefficient of the block material by a maximum of 5*10−6/K.