Alkali metal diffusion barrier layer
First Claim
1. An article comprising:
- a glass substrate having alkali metal ions in a surface;
a medium over and spaced from the surface of the substrate, the medium characterized in that predetermined concentrations of alkali metal ion deteriorates the function of the medium, and between the surface and the medium a sputtered amorphous layer of a metal oxide having a thickness of less than 180 Angstroms and having a density equal to or greater than 75% of its crystalline density to provide an alkali metal ion barrier layer between the glass substrate and the medium.
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Accused Products
Abstract
Amorphous metal oxide barrier layers of titanium oxide, zirconium oxide and zinc/tin oxide are effective as alkali metal ion barrier layers at thicknesses below 180 Angstroms. The amorphous metal oxide barrier layers are most effective when the density of the layer is equal to or greater than 75% of the crystalline density. The barrier layers prevent migration of alkali metal ions such as sodium ions from glass substrates into a medium e.g. electrolyte of a photochromic cell, liquid material of a liquid crystal display device contacting the glass surface and a photocatalytic coating. The properties of the medium, particularly electroconductive metal oxide coatings, are susceptible to deterioration by the presence of sodium ions migrating from the glass.
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Citations
15 Claims
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1. An article comprising:
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a glass substrate having alkali metal ions in a surface;
a medium over and spaced from the surface of the substrate, the medium characterized in that predetermined concentrations of alkali metal ion deteriorates the function of the medium, and between the surface and the medium a sputtered amorphous layer of a metal oxide having a thickness of less than 180 Angstroms and having a density equal to or greater than 75% of its crystalline density to provide an alkali metal ion barrier layer between the glass substrate and the medium. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An article comprising:
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a glass substrate having a predetermined transmission at 550 nanometers, an index of refraction and alkali metal ions in a surface;
a medium over and spaced from the surface of the substrate, the medium characterized in that predetermined concentration of alkali metal ion deteriorates the function of the medium, and between the surface and the medium a sputtered layer of a metal oxide having a thickness less than 180 Angstroms, an index of refraction higher than the index of refraction of the glass substrate and the layer when applied directly on the glass does not lower the transmission of the substrate at 550 nanometers more than 10%.
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Specification