Contamination is blocked from material of a color filter layer provided on a thin-film transistors (TFT) supporting substrate by sealing over the color filter layer with an inorganic insulating layer. During mass production manufacture, a plasma surface cleaning step is employed after the color filter layer is deposited but before the inorganic insulating layer is deposited. A low temperature CVD process is used to deposit the inorganic insulating layer with a substantially uniform thickness conformably over the color filter layer including conformably into openings provided through the color filter layer.