Transparent substrate with antireflection coating
First Claim
Patent Images
1. A coated transparent substrate, comprising:
- a transparent substrate including alkali metal ions; and
an antireflection coating on at least one surface of said substrate, wherein said coating is a stack of dielectric material layers having alternating high and low refractive indices, at least one of said layers is a shield layer which prevents diffusion of said alkali metal ions from said substrate through said shield layer, and said shield layer is a high refractive index dielectric material layer selected from the group consisting of silicon nitride and aluminum nitride, and said coated transparent substrate has a light reflection RL of at most 2% and a blue or blue-green color in reflection, with a variation of RL of at most 0.3% and variations of a* and b* in reflection of at most 2.0 after heating.
0 Assignments
0 Petitions
Accused Products
Abstract
The invention relates to a glass substrate having on at least one of its faces an antireflection coating formed by a stack of thin dielectric material layers having alternately high and low refractive indices. To prevent the modification of the optical properties of the coating in the case where the substrate is subject to a heat treatment such as tempering, bending or annealing, the layer or layers of the stack which are liable to deteriorate on contact with alkali ions such as sodium ions are separated form the substrate by at least one layer forming part of the antireflection coating and forming a “shield” with respect to the diffusion of alkali.
-
Citations
31 Claims
-
1. A coated transparent substrate, comprising:
-
a transparent substrate including alkali metal ions; and
an antireflection coating on at least one surface of said substrate, wherein said coating is a stack of dielectric material layers having alternating high and low refractive indices, at least one of said layers is a shield layer which prevents diffusion of said alkali metal ions from said substrate through said shield layer, and said shield layer is a high refractive index dielectric material layer selected from the group consisting of silicon nitride and aluminum nitride, and said coated transparent substrate has a light reflection RL of at most 2% and a blue or blue-green color in reflection, with a variation of RL of at most 0.3% and variations of a* and b* in reflection of at most 2.0 after heating. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
antireflection coating/glass/polyvinylbutyral/glass/antireflection coating.
-
-
25. The coated transparent substrate of claim 1, wherein said shield layer is in contact with the substrate.
-
26. The coated transparent substrate of claim 1, wherein said stack comprises an intermediate refractive index layer in contact with said substrate and a sequence of layers of high and low refractive indices on said intermediate refractive index layer.
-
27. The coated transparent substrate of claim 1, wherein said coating is a stack of four layers having alternating high and low refractive indices or a stack of six layers having alternating high and low refractive indices.
-
28. The coated transparent substrate of claim 1, wherein one of said high refractive index layers is a superposition of two or three different layers.
-
29. The coated transparent substrate of claim 1, wherein said substrate comprises bent glass or tempered glass.
-
30. A process for producing a coated transparent substrate, the process comprising
depositing a first dielectric material layer on a glass substrate by pyrolysis of dielectric material precursors; -
forming a second dielectric material layer on said first material layer by cathodic sputtering; and
forming the coated transparent substrate of claim 1.
-
-
31. The coated transparent substrate of claim 1, wherein said shield layer prevents diffusion of alkali metal ions from said substrate to a layer comprising metallic oxides having multiple valencies.
Specification