Reflectors in the automotive, indoor lighting and decorative industry are often manufactured by vacuum metallization of plastic parts. Handling and mechanical stress during assembly, distribution and installation cause scrap due to wiping and scratching damage. Consequently, there is a demand to equip the reflective coating with a wipe or abrasion protection. Previous approaches involve lacquering with its disadvantages, while vacuum processes - mainly Plasma-CVD- did not gain commercial success yet. Leybold Optics follows the vacuum approach by combining vacuum metallization with Plasma-CVD hard coat layers in a single process, possible on common reflector coating machines. One challenge is to maintain the reflectivity and color impression (brilliance) of the reflector, which is affected by protection layers either underneath or on top of the metal layer. Therefore, careful stack design is required to balance those influences. Wipe resistivity scales with layer thickness, however cycle times have to be comparable to the standard processes in order to keep the additional layer features economically attractive. This poses additional challenges to speed up the process without entering unwanted regimes like dust formation during Plasma-CVD. The paper describes a solution that achieves a major improvement in wipe protection while maintaining the reflectivity, brilliance, reasonable cycle times and coating costs.
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