Multilayer structure for hard coating

A film layer stack, comprising:

• an anti-reflective layer having single-layer or multilayer structure or sub-structure and uniform or nonuniform structure or sub-structure;
• a hard overcoat layer having single-layer or multilayer structure or sub-structure and uniform or nonuniform structure or sub-structure;
• and
• an adhesion layer having single-layer or multilayer structure or sub-structure and uniform or nonuniform structure or sub-structure;
• wherein the anti-reflective layer, the hard overcoat layer or the adhesion layer comprises at least one graded index of refraction layer having index of refraction graded through a layer thickness.

A film layer stack, comprising:

• a plurality of first and second layers, each of the second layers sandwiched by such first layers, such first layers having lower index of refraction than such second layers;
• each of the second layers comprising a cation oxynitride material layer;
• and
• each of the second layers having a graded index of refraction through a thickness of the second layer, comprising:
• an upper portion of the thickness of the second layer, having a lower index of refraction of the graded index of refraction;
• a middle portion of the thickness of the second layer, having a higher index of refraction of the graded index of refraction;
• and
• a lower portion of the thickness of the second layer, having a lower index of refraction of the graded index of refraction.

A method of making a film layer having a graded index of refraction through a thickness of the film layer, comprising:

• using a sputtering source and physical vapor deposition (PVD) to deposit the film layer;
• and
• varying gas flows over time during the physical vapor deposition, with oxygen gas flow decreasing while nitrogen gas flow is increasing followed by the nitrogen gas flow decreasing while the oxygen gas flow is increasing, to deposit:
• an upper portion of the thickness of the film layer, having a lower index of refraction of the graded index of refraction;
• a middle portion of the thickness of the film layer, having a higher index of refraction of the graded index of refraction;
• and
• a lower portion of the thickness of the film layer, having a lower index of refraction of the graded index of refraction.

A method of making a film layer having a graded index of refraction through a thickness of the film layer, comprising:

• using at least one sputtering source and physical vapor deposition (PVD) to deposit the film layer on a substrate;
• and
• positioning or moving the substrate, relative to the at least one sputtering source, during the physical vapor deposition, in a first zone having lower index of refraction material deposition, a second zone having higher index of refraction material deposition, and a third zone having lower index of refraction material deposition, to deposit:
• an upper portion of the thickness of the film layer, having a lower index of refraction of the graded index of refraction;
• a middle portion of the thickness of the film layer, having a higher index of refraction of the graded index of refraction;
• and
• a lower portion of the thickness of the film layer, having a lower index of refraction of the graded index of refraction.