Heat treatable coated glass

• US 20010003628A1
• Filed: 01/03/2001
• Published: 06/14/2001
• Est. Priority Date: 07/07/1999
• Status: Active Grant

• Current Assignee: Hulya Demiryont
• Original Assignee: Hulya Demiryont
• Inventors: Demiryont, Hulya
• Granted Patent: US 6,412,307 B2
• Time in Patent Office: Days
• US Class Current: 428/630
• CPC Class Codes: C03C 17/36 at least one coating being a metal
• CPC Class Codes: C03C 17/3618 Coatings of type glass/inorganic compound/other inorganic layers, at least one layer being metallic
• CPC Class Codes: C03C 17/3644 the metal being silver
• CPC Class Codes: C03C 17/3652 the coating stack containing at least one sacrificial layer to protect the metal from oxidation
• CPC Class Codes: C03C 17/366 Low-emissivity or solar control coatings
• CPC Class Codes: C03C 17/3681 the multilayer coating being used in glazing, e.g. windows or windscreens
• CPC Class Codes: C03C 2217/78 Coatings specially designed to be durable, e.g. scratch-resistant
• CPC Class Codes: C23C 14/086 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 14/185 by cathodic sputtering
• CPC Class Codes: Y10T 428/12549 Adjacent to each other
• CPC Class Codes: Y10T 428/12597 Noncrystalline silica or noncrystalline plural-oxide component [e.g., glass, etc.]
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

A heat-treatable coated glass article comprises a substantially transparent substrate with a substantially transparent dual-function coating on a surface of the substrate. The coating provides low emissivity and high anti-solar performance properties. It comprises a first anti-reflection layer of dielectric material, preferably tungsten oxide. An infra-red reflective layer of silver metal and/or copper metal overlies the anti-reflection dielectric layer. A buffer layer, such as a chromium buffer layer, is positioned between the anti-reflection layer and the infra-red reflective layer. Also, optionally, a color control layer may be used, preferably being positioned between the anti-reflection layer and the substrate. A second buffer layer directly overlies the infra-red reflective layer. A second anti-reflection layer overlies the second buffer layer. In accordance with a method of manufacturing the coated article, each of the layers of the coating is deposited in turn by D.C. magnetron sputtering in a multi-station sputtering chamber. Passing the transparent substrate through the sputtering chamber a second time to produce a double-layer coating structure is found to provide especially high quality performance characteristics.

Claims

1. A heat-treatable coated glass article comprising a substantially transparent glass substrate with a substantially transparent coating on a surface of the glass substrate, the substantially transparent coating comprising:

a first anti-reflection layer of dielectric material overlying the glass substrate,

a first chromium buffer layer overlying the first anti-reflection layer,

an infra-red reflective layer of metal selected from silver metal, copper metal and a mixture of both, directly overlying the first buffer layer,

a second chromium buffer layer directly overlying the infra-red reflective layer,

and

a second anti-reflection layer of dielectric material overlying the second buffer layer.

2. The coated article of manufacture according to

claim 1

wherein the infra-red reflective layer is silver metal and the first and second anti-reflection layers each is SnO₂.

3. The heat-treatable coated glass article according to

claim 2

wherein the thickness of each chromium buffer layer is 10% to 30% of the thickness of the infra-red reflective layer of silver metal.

4. The heat-treatable coated glass article according to

claim 2

wherein the thickness of each chromium buffer layer is 1 nm to 5 nm and the thickness of the infra-red reflective layer of silver metal is 6 nm to 13 nm.

5. The heat-treatable coated glass article according to

claim 4

wherein the first and second anti-reflection layers of SnO₂ each has a substantially uniform thickness from 20 nm to 50 nm.

6. The heat-treatable coated glass article according to

claim 1

wherein said glass is not heat-treated and, when the glass has a thickness of about 2.2 mm to 6 mm, has the following characteristics:

grey-blue color and substantially free of haze;

visible transmittance of 40% to 70%; and

sheet resistance of not more than 7 ohms/sq.

7. The heat-treatable coated glass article according to

claim 1

wherein said glass is heat-treated clear glass and, when the glass has a thickness of about 2.5 mm to 6 mm, has the following characteristics after heat-treatment:

substantially free of haze;

visible transmittance of 50% to 80%; and

sheet resistance of not more than 5 ohms/sq.

8. The heat-treatable coated glass article according to

claim 1

wherein the first anti-reflection layer lies directly on the surface of the glass.

9. The heat-treatable coated glass article according to

claim 8

wherein the first chromium buffer layer lies directly on the first anti-reflection layer.

10. The heat-treatable coated glass article according to

claim 9

wherein the infra-red reflective layer directly overlies the first chromium buffer layer.

11. The heat-treatable coated glass article according to

claim 10

wherein the second chromium buffer layer directly overlies the infra-red reflective layer.

12. The heat-treatable coated glass article according to

claim 11

wherein the second anti-reflection layer directly overlies the second buffer layer.

13. The heat-treatable coated glass article according to

claim 1

wherein the substantially transparent glass substrate is soda-lime-silica glass.

14. A motor vehicle windshield comprising a polymer sheet sandwiched between a first heat-treated glass substrate bent to a curved shape, a second heat-treated glass substrate bent to a matching curved shape, and a substantially transparent coating on a surface of at least one of the heat-treated glass substrates, the substantially transparent coating comprising:

a first anti-reflection layer of SnO₂ overlying the glass substrate and having a thickness of about 39 nm;

a first chromium buffer layer overlying the first anti-reflection layer and having a thickness of about 2 nm;

an infra-red reflective layer of silver metal directly overlying the first buffer layer and having a thickness of about 95 nm;

a second chromium buffer layer directly overlying the infra-red reflective layer and having a thickness of about 2.5 nm; and

a second anti-reflection layer of SnO₂ overlying the second buffer layer and having a thickness of about 39 nm;

wherein, when the first heat-treated glass substrate and the second heat-treated glass substrate each is substantially clear soda-lime-silica glass having a thickness of about 2.2 mm, the windshield has the following spectral properties;

visible light transmittance greater than 75%;

total solar energy transmittance less than 50%; and

total solar reflectance (IR region) of at least 25%.

15. A heat-treatable coated glass article comprising a substantially transparent glass substrate with a substantially transparent coating on a surface of the glass substrate, the substantially transparent coating comprising:

a first anti-reflection layer of dielectric material overlying the glass substrate,

a first buffer layer overlying the first anti-reflection layer,

a first infra-red reflective layer of silver metal directly overlying the first buffer layer, a second buffer layer directly overlying the infra-red reflective layer,

a second anti-reflection layer of dielectric material overlying the second buffer layer, a third buffer layer overlying the second anti-reflection layer,

a second infra-red reflective layer of silver metal directly overlying the third buffer layer, a fourth buffer layer overlying the second infra-red reflective layer of silver metal, and a third anti-reflection layer of dielectric material overlying the fourth buffer layer.

16. The heat-treatable coated glass article of

claim 15

wherein each of the anti-reflection layers is SnO₂ and the buffer layers each is a chromium buffer layer.

17. A motor vehicle windshield having low reflectance of visible light and high transmittance of visible light, comprising a polymer sheet sandwiched between a first heat-treated glass substrate bent to a curved shape, a second heat-treated glass substrate bent to a matching curved shape, and a substantially transparent coating on a surface of at least one of the heat-treated glass substrates, the substantially transparent coating comprising:

a first anti-reflection layer of dielectric material overlying the glass substrate,

a first buffer layer overlying the first anti-reflection layer,

a first infra-red reflective layer of silver metal directly overlying the first buffer layer, a second buffer layer directly overlying the infra-red reflective layer,

a second anti-reflection layer of dielectric material overlying the second buffer layer, a third buffer layer overlying the second anti-reflection layer,

a second infra-red reflective layer of silver metal directly overlying the third buffer layer, a fourth buffer layer overlying the second infra-red reflective layer of silver metal, and

a third anti-reflection layer of dielectric material overlying the fourth buffer layer.

18. The motor vehicle windshield in accordance with

claim 17

wherein the polymer sheet is sandwiched between the concave side of the first heat-treated glass substrate and the convex side of the second heat-treated glass substrate, the substantially transparent coating being on the concave side of the first heat-treated glass substrate.

19. The motor vehicle windshield in accordance with

claim 17

wherein the first and second anti-reflection layers are SnO₂, the buffer layers are chromium buffer layers, the thickness of each chromium buffer layer is 1 nm to 4 nm and the thickness of the infra-red reflective layer of silver metal is 6 nm to 13 nm, and wherein the windshield, when the glass is clear soda-lime-silica glass having a thickness of 2.2 mm to 3.5 mm, has the following spectral characteristics:

visible light transmittance greater than 75%;

total solar energy transmittance less than 50%; and

total solar reflectance (IR region) of at least 25%.

20. The motor vehicle windshield in accordance with

claim 19

wherein the first buffer and the second buffer have the same thickness.

21. The motor vehicle windshield in accordance with

claim 19

wherein the first buffer layer has a thickness less than that of the second buffer layer.

22. The motor vehicle windshield in accordance with

claim 19

wherein each of the buffer layers is a chromium buffer layer.

23. The motor vehicle windshield in accordance with

claim 19

wherein the first buffer layer is at least 1.5 nm thick.

24. A method of manufacturing a heat-treatable coated glass article comprising a substantially transparent glass substrate with a substantially transparent coating on a surface of the glass substrate, comprising the steps of:

providing a substantially transparent glass substrate; and

forming a substantially transparent coating on a surface of the substrate by;

A) depositing a first anti-reflection layer of dielectric material,

B) subsequently depositing a first chromium buffer layer overlying the first anti-reflection layer;

C) subsequently depositing silver metal or copper metal over the first chromium buffer layer to form a first infra-red reflection layer,

D) subsequently depositing a second chromium buffer layer directly onto the infra-red reflective layer, and

E) subsequently depositing a second anti-reflection layer of dielectric material over the second buffer layer to form a second anti-reflection layer.

25. The method of manufacturing a heat-treatable coated glass article according to

claim 24

wherein the first anti-reflection layer is deposited directly onto the surface of the glass substrate.

26. The method of manufacturing a heat-treatable coated glass article according to

claim 24

wherein the layers of steps (A) through (E) are deposited in that order by magnetron sputtering at a corresponding series of stations within a sputtering chamber as the glass substrate moves continuously from station to station within the sputtering station.

27. The method of manufacturing a heat-treatable coated glass article according to

claim 25

wherein the substantially transparent glass substrate is soda-lime-silica glass and the method further comprises, subsequent to step (E), bending the glass substrate in tandem with a second glass substrate.