Highly durable first surface silver based optical coatings and method of making the same
View Patent ↗A highly durable, environmentally and thermally stable Silver coating for mirrors, Infrared thin-film filters, or other optical coatings having very high reflection values over a large spectral and angular range where the enhanced durability and thermal stability are achieved through the selection and layer sequence of materials, which provide good chemical and environmental protection to Silver. Of particular importance are the layers directly below the Silver, and directly above the Silver (nucleation layer and barrier layer). It is important that the materials of those two layers provide diffusion barriers for Oxygen, water vapour and other corrosive gases, and are compatible in such a way that the layer below the Silver provides a good nucleation bed for Silver assuring that Silver will grow dense and highly reflective, and in some cases, when deposited in very thin layers, highly transparent in the visible spectrum, and the material of the layer directly above the Silver layer has to be compatible with Silver in a sense that it grows dense on the top of Silver, does not reduce the reflectivity of Silver, and also provides a good nucleation layer for the next layer being deposited.
1. A coated article comprising a vacuum deposited layer system supported by a glass, metal, ceramic or plastic substrate having a nucleation layer below a Silver layer comprising:
a vacuum deposited nucleation layer comprising YF 3 ; and,
a vacuum deposited Silver layer above said YF 3 comprising layer.
2. A coated article comprising a vacuum deposited layer system supported by a glass, metal, ceramic or plastic substrate having a nucleation layer below a Silver layer and a barrier layer above the Silver layer comprising:
a vacuum deposited nucleation layer comprising YF 3 ;
a vacuum deposited Silver layer; and,
a vacuum deposited barrier layer comprising YF 3 or MgF 2 .
3. The coated article of claim 2 wherein said vacuum deposited barrier layer is a YF 3 comprising layer and further comprising at least one MgF 2 and/or AIF 3 , TiO 2 , Nb 2 O 5 , Ta 2 O5, ZrO 2 , or HfO 2 comprising layer above said barrier layer YF 3 comprising layer.
4. The coated article of claim 3 wherein said MgF 2 and/or AIF 3 , TiO 2 , Nb 2 O 5 , Ta 2 O5, ZrO 2 , or HfO 2 comprising layer is directly above and adjacent to said barrier layer YF 3 comprising layer.
5. The coated article of claim 2 comprising a vacuum deposited nucleation layer comprising YF 3 , and having one or more of the metals Titanium, Niobium, Zirconium, Molybdenum, Chromium, alloys such as NiCr, and/or their Nitrides, Oxides, sub-Oxides or alloys, noble metals, and/or MgF2 comprising layer below said nucleation layer.
6. The coated article of claim 2 further comprising multiple additional Silver layers deposited above said vacuum deposited barrier layer comprising YF 3 or MgF 2 with spacer layers between said additional Silver layers, said spacer layers further comprising YF 3 , or YF 3 /MgF 2 /YF 3 , or YF 3 /ALF 3 /YF 3 .