Vacuum ultraviolet (VUV) excimer light sources (172nm) have a photon energy large enough to break down organic matter, and so are often used for surface modification of plastics, for example, to bond surfaces without using adhesive. However, it takes heat (<100°C) and pressure (<1MPa). In addition, VUV light (172nm) is strongly absorbed by atmospheric oxygen, and one way to overcome this problem is to use vacuum equipment. It is possible to control the reaction chamber by introducing a reactive gas. PTFE, PVDF, etc., the reformer is difficult. However, there are reported to be reformed in this way. Excimer VUV lamps have been used for photo-chemical vapor deposition (CVD), for example, to deposit a-Si: H films, but few cases exist where this is used in commercial products. Nevertheless, recent improvements in excimer lamp performance are expected to lead to increased application in photo-CVD.