Mirrors and their production
AssigneePilkington United Kingdom Limited
InventorTimothy Jenkinson
Life of this patent
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Abstract
The green reflection color of back surface mirrors produced by deposition of a reflecting layer over two reflection enhancing layers on a glass substrate is controlled by selection of the layer materials and thicknesses to provide a reflection color having an a* value greater than -6, with a light reflection of at least 65%, preferably at least 70%. The inner reflection enhancing layer and reflecting layer are preferably of silicon, with the inner reflection enhancing layer having an optical thickness less than 125 nm; the intermediate reflection enhancing layer, which may be of silicon oxide, preferably has an optical thickness greater than 125 nm. The mirror may be produced by depositing the successive layers on a hot ribbon of glass during the glass production process.
Claims14
A back surface mirror comprising a glass substrate having a thickness of greater than 2 mm carrying a reflecting coating comprising a reflecting layer and at least two reflection enhancing layers, the thicknesses and refractive indices of the layers of said reflecting coating being selected to provide a visible light reflection of at least 65% with a reflection colour having an a* value greater than -6;
- wherein the reflection enhancing layer closest to said glass substrate is a silicon layer having an optical thickness of less than 125 nm.
A back surface mirror comprising a glass substrate carrying an inner reflection enhancing layer of silicon of optical thickness less than 100 nm, an intermediate reflection enhancing layer of silicon oxide of optical thickness greater than 140 nm and an outer reflecting layer of silicon.
A method of producing back surface mirrors comprising depositing onto a ribbon of hot glass of thickness greater than 2 mm during the glass production process an inner reflection enhancing layer of silicon having an optical thickness less than 125 nm and a second reflection enhancing layer followed by a reflecting layer, the resulting mirrors have a visible light reflection of at least 65% with a reflection colour having an a* value of greater than -6.
Dependencies are inferred from the claim text.