Device for applying a liquid medium which is exposed to uv radiation to a substrate

Abstract

An apparatus for applying a liquid medium irradiated with UV radiation onto a substrate is disclosed, the apparatus comprising: a housing having an elongated chamber, at least one inlet opening, which opens into the chamber, and at least one slit shaped outlet opening opposite the inlet opening, which extends over the length of the chamber, a tube element, which extends in a longitudinal direction through the chamber, the tube element being at least partially transparent to UV radiation, wherein the tube element is arranged in the chamber such that a flow space is formed between the tube element and the wall of the chamber, the flow space being symmetric with respect to a longitudinal centre plane of the chamber, the longitudinal centre plane dissecting the outlet opening in its middle, and such that the tube element extends into the slit shaped outlet opening in the housing and thereby forms two longitudinally extending outlet slits between the tube element and the housing, and at least one UV-radiation source in the tube element, which is arranged to emit UV-radiation in the direction of the flow space and through the outlet opening out of the housing. The apparatus is distinguished by means for causing UV radiation to be emitted primarily in a first wavelength range through a first section of the tube member into the flow space and for causing UV radiation to be emitted primarily in a second wavelength range through a second section of the tube member through the outlet opening of the housing and optionally into an end region of the flow space adjacent to the outlet slits. The first and second wavelength ranges differ, and wherein for at least one of the sections, a maximum of 20%, preferably a maximum of 5%, of the radiation power emitted through the respective section comes from the other wavelength range.