METHOD AND DEVICE FOR MICROWAVE PLASMA DEPOSITION OF A COATING ON A THERMOPLASTIC CONTAINER SURFACE

摘要

The deposition of a coating on a thermoplastic container surface using low pressure plasma by excitation of a precursor gas with UHF electromagnetic waves in a circular shaped vacuum cavity receiving the container is provided. It includes dimensioning the cavity with respect to the frequency of the UHF electromagnetic waves so as to obtain a coupling mode generating several electromagnetic fields inside the cavity. In particular a TM 120 coupling mode is provided which generates two central fields (4_A, 4_B) inside the cavity, whereby two containers can be simultaneously treated in said cavity.