Antireflection coatings

An antireflective composite having a visible light reflectance below 8% comprising

• a polyester substrate having an index of refraction of from about 1.4 to 1.7 and a surface having an inherent reflection of about 12%, said surface having adhered thereto a discontinuous 70 to 170 nm thick antireflection layer of oolitic-dendritic aggregates of a transparent inorganic metal compound, said aggregates having a diameter of 5-250 nm and a packing density of 0.2 to 0.7, said layer having an index of refraction of from 1.7 to 2.7, and said transparent inorganic metal compound being selected from the group consisting of oxides and nitrides of tantalum, titanium, niobium, hafnium, tungsten and zirconium.

An antireflective composite comprising a solid organic polymer substrate having adhered thereto a discontinuous 10-300 nm thick antireflection material, said material having a first layer of oolitic-dendritic aggregates of a first transparent inorganic metal oxide or oxynitride, said aggregates having a diameter of 5-250 nm and a second layer of oolitic-dendritic aggregates of a second transparent inorganic metal oxide or oxynitride, said aggregates having a diameter of 5-250 nm and being adhered to and built upon the first layer and wherein each of the first and second layers has an index of refraction which is greater than the index of refraction of the polymer substrate the antireflection material as a whole has a packing density of 0.1 to 0.7.

An antireflective composite having a visible light reflectance below 8% comprising

• a polyester substrate having an index of refraction of from about 1.4 to 1.7 and having an inherent reflectance of about 12% and having adhered thereto a first layer of a 25 to 100 nm thick, discontinuous antireflection material, said first layer having oolitic-dendritic aggregates of a first transparent inorganic metal compound selected from the group consisting of oxides and oxynitrides of tantalum, titanium, niobium, hafnium, tungsten and zirconium, said aggregates having a diameter of 5-250 nm and a second layer of oolitic-dendritic aggregates of a second transparent inorganic metal compound selected from the group consisting of oxides and oxynitrides of zinc, tin and indium, said aggregates having a diameter of 5-250 nm and being adhered to and built upon the first layer and wherein each of the first and second layers has an index of refraction of 1.7 to 2.7 and the antireflection material as a whole has a packing density of 0.2 to 0.7.

A process for imparting antireflection properties to a composite material comprising sputter-depositing upon a solid organic polymer substrate a 10-300 nm thick discontinuous antireflection layer of oolitic-dendritic aggregates of a transparent inorganic metal oxide or oxynitride, said aggregates having a diameter of 5-250 nm and a packing density of 0.1 to 0.7, said antireflection layer having an index of refraction greater than the index of refraction of the substrate.

A process for imparting antireflection properties to a composite material comprising sputter-depositing upon a solid organic polymer substrate a 10-300 nm thick discontinuous antireflection material said material having a first layer of oolitic-dendritic aggregates of a first transparent inorganic metal oxide or oxynitride, said aggregates having a diameter of 5-250 nm and a second layer of oolitic-dendritic aggregates of a second transparent inorganic metal oxide or oxynitride, said aggregates having a diameter of 5-250 nm and being adhered to and built upon the first layer and wherein each of the first and second layers has an index of refraction which is greater than the index of refraction of the polymer substrate and the antireflection material as a whole has a packing density of 0.1 to 0.7.