Vacuum coating apparatus

A box coating apparatus for vacuum coating of substrates, in particular spectacle lens blanks, comprising a vacuum chamber which contains an evaporation source and a substrate holder for holding a plurality of substrates, said substrate holder being formed as a dome disposed relative to said evaporation source and rotatable by a dome rotary drive about an axis of rotation that passes through said evaporation source, so that substrates held by said substrate holder can be moved on circular paths about said axis of rotation with a respective constant spacing relative to said evaporation source, wherein a masking arrangement is located in said vacuum chamber between said evaporation source and said substrate holder for partially shadowing the substrates held by said substrate holder relative to said evaporation source, characterized in that said masking arrangement comprises a fixed masking portion that is stationary in said vacuum chamber, and a plurality of gradient sector portions each carrying gradient shields assigned to the substrates held by said substrate holder, for forming a gradient mask, wherein said gradient sector portions can be rotated about said axis of rotation between a gradient mask open position in which said gradient sector portions are stored behind said fixed masking portion, and a gradient mask closed position in which said gradient sector portions are spread like a fan between said evaporation source and said substrate holder.