Coating technology PVD coating


The coating technology employed by S1 Optics is the PVD (physical vapour deposition) coating process. PVD coating describes a coating process in thin-film technology which takes place in a vacuum and in which the layer is formed on the substrates through condensation of a material vapour.

This coating technology is used for producing optical coatings on glass or metal substrates. PVD processes for optical coatings on plastic substrates are possible using a plasma source, as this allows good layer properties to be achieved despite low temperatures.

The PVD process can be used to deposit a variety of metals, oxides, nitrides and semiconductors. If reactive gases such as oxygen (O2) or nitrogen (N2) are added, it is also possible to deposit oxides or nitrides in stoichiometric form. These thin layers are used primarily in the electrical industry, in medical technology and in lighting technology, but also for creating optical coatings. The thicknesses of such layers are in the nanometre (nm) range. They are usually vapour-deposited one on top of another to create a multi-layer system with total layer thicknesses up to a few microns (µm), giving a very high layer quality. This creates dense, homogeneous and ductile layers which cannot be achieved by conventional methods.

PVD coating essentially passes through three stages:

  • 1. The layer material is converted to the gaseous state
  • 2. The vapour is transported through the low-pressure gas atmosphere between source and substrate.
  • 3. The vapour condenses, on the surface of the substrate in particular, to form a thin layer.

The PVD process is used for coating (electron beam physical vapour deposition, resistance vapour deposition, ion-assisted deposition (IAD) processes).

Use is made of modern coating units with high-quality features in terms of vacuum, sources of evaporation and plasma, system control, optical monitor etc.

This method is characterized by high layer density and thus high mechanical strength, by low drift on change of temperature and by optical properties with outstanding climate stability and long-term stability overall.