Device for depositing a coating on an internal surface of a container

Abstract

Device for depositing a coating on an internal surface of a container, of the type in which the deposition is carried out by means of a low-pressure plasma created inside the container by excitation of a precursor gas by microwave-type electromagnetic waves. An injection tube is provided that dips into the container to a length of between one quarter and one half of the total height of the container in question, between the top and the bottom of the container said length of the injection tube constituting a longitudinal antenna capable of picking up a UHF electromagnetic wave generated by said generator and of propagating the HT ignition signal, a UHF short-circuit in the form of a plate being provided on the injection tube in such a way that the face of said plate on the cavity side defines a point of zero amplitude of the electromagnetic wave propagating along said injection tube, the length between said short-circuit and the free end of said injection tube corresponding to an odd number of quarter-wavelengths so as to obtain a maximum amplitude, that is to say an antinode, at the free end of the injection tube.