Double silver low-emissivity and solar control coatings

• US 7,632,572 B2
• Filed: 05/07/2007
• Issued: 12/15/2009
• Est. Priority Date: 09/04/2001
• Status: Expired due to Term

• Current Assignee: Cardinal CG Company (Cardinal Glass Industries Incorporated)
• Original Assignee: AGC Flat Glass North America Incorporated (AGC, Inc.)
• Inventors: Glenn, Darin, Dannenberg, Rand, Johnson, Herb, Countrywood, Joe, Sieck, Peter A.
• Primary Examiner(s): Speer; Timothy M
• Application Number:
  US11/745,243
• Publication Number:
  US 20070207327A1
• Time in Patent Office: 953 Days
• Field of Search: None
• US Class Current: 428/434
• 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 17/3626 one layer at least containing a nitride, oxynitride, boronitride or carbonitride
• CPC Class Codes: C03C 17/3639 Multilayers containing at least two functional metal layers
• 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 2217/78 Coatings specially designed to be durable, e.g. scratch-resistant
• CPC Class Codes: G02B 5/282 reflecting for infrared and transparent for visible light, e.g. heat reflectors, laser protection
• CPC Class Codes: Y10T 428/12618 Plural oxides
• 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 low-emissivity multilayer coating includes, in order outward from the substrate, a first layer including a layer containing titanium oxide, a layer containing silicon nitride, or a sublayer layer containing titanium oxide in combination with a sublayer containing silicon nitride; a second layer including Ag; a third layer including at least one layer selected from titanium oxide layers and silicon nitride layers; a fourth layer including Ag; and a fifth layer including silicon nitride. The color of the coatings can be varied over a wide range by controlling the thicknesses of the layers of titanium oxide, silicon nitride and Ag. A diffusion barrier of oxidized metal protects relatively thin, high electrical conductivity, pinhole free Ag films grown preferentially on zinc oxide substrates. Oxygen and/or nitrogen in the Ag films improves the thermal and mechanical stability of the Ag. Dividing the first layer of titanium oxide, the Ag layers, and/or the third layer with a sublayer of oxidized metal can provide greater thermal and mechanical stability to the respective layers.

Claims

1. A low-emissivity coating on a substrate, the coating comprising, in numerical order outward from the substrate,

a first layer including at least one layer selected from titanium oxide layers and silicon nitride layers;

a second layer including Ag;

a third layer including at least one layer selected from titanium oxide layers and silicon nitride layers;

a fourth layer including Ag; and

a fifth layer including silicon nitride, wherein

at least one of the second layer and the fourth layer comprises

a sublayer including Ag, and

a sublayer consisting of a fully oxidized Ni—

Cr alloy directly on, and outward from the substrate from, the Ag of the sublayer including Ag.

2. The coating according to claim 1, wherein the first layer is from 5 to 30 nm thick.

3. The coating according to claim 1, wherein

the first layer includes a titanium oxide layer;

and

the titanium oxide in the first layer is amorphous.

4. The coating according to claim 1, wherein the third layer comprises at least one of a TiO₂ layer and a Si₃N₄ layer.

5. The coating according to claim 1, wherein the third layer comprises a superlattice of titanium oxide and silicon nitride.

6. The coating according to claim 1, wherein at least one of the second layer and the fourth layer consists of, in numerical order outward from the substrate,

a first sublayer, which includes a zinc oxide;

a second sublayer, which includes Ag; and

a third sublayer, which includes a fully oxidized Ni—

Cr alloy.

7. The coating according to claim 6, wherein the zinc oxide comprises nitrogen.

8. The coating according to claim 1, wherein the Ag in at least one of the second layer and the fourth layer further comprises at least one of oxygen and nitrogen.

9. The coating according to claim 1, wherein the Ag in at least one of the second layer and the fourth layer further comprises a means for strengthening the Ag against thermally induced changes.

10. The coating according to claim 1, wherein at least one of the first layer, the second layer, the third layer, and the fourth layer is divided by a layer of an oxidized metal.

11. The coating according to claim 10, wherein the oxidized metal is an at least partially oxidized Ni—

Cr alloy.

12. The coating according to claim 1, wherein at least one layer of the first layer, the second layer, the third layer, and the fourth layer is divided by a layer including a means for strengthening the at least one layer against thermally induced changes.

13. The coating according to claim 1, wherein the silicon nitride comprises less than a stoichiometric amount of nitrogen.

14. The coating according to claim 1, wherein

the first layer includes a layer of SiN_x, where 0<

x≦

1.34;

the third layer includes a layer of SiN_x, where 0<

x≦

1.34; and

the fifth layer includes a layer of SiN_x, where 0<

x≦

1.34.

15. The coating according to claim 14, wherein the first layer includes a layer of SiN_x, where x=1.34.

16. A method of making a low-emissivity coating on a substrate, the method comprising

depositing at least one layer including Ag on the substrate;

and

producing the coating of claim 1.

17. The method according to claim 16, wherein the depositing comprises sputtering.

18. A method of making a low-emissivity coating on a substrate, the method comprising

a step for depositing at least one layer including Ag on the substrate;

and

producing the coating of claim 1.

19. A low-emissivity coating on a substrate, the coating comprising, in numerical order outward from the substrate,

a first layer including at least one layer selected from titanium oxide layers and silicon nitride layers;

a second layer including a first means for reflecting infrared radiation;

a third layer having an index of refraction greater than or equal to 1.9 at a wavelength of 550 nm;

a fourth layer including a second means for reflecting infrared radiation; and

a fifth layer including a means for protecting the coating from abrasion, wherein

at least one of the first means for reflecting infrared radiation and the second means for reflecting infrared radiation comprises

a sublayer including Ag, and

a sublayer consisting of a fully oxidized Ni—

Cr alloy directly on, and outward from the substrate from, the Ag of the sublayer including Ag.

20. The coating according to claim 19, wherein

at least one of the first means for reflecting infrared radiation and the second means for reflecting infrared radiation consists of, in numerical order outward from the substrate, a first sublayer, a second sublayer, which includes Ag, and a third sublayer, which includes a fully oxidized Ni—

Cr alloy; and

the first sublayer includes a means for preferentially orienting a crystal structure of the second sublayer.

21. The coating according to claim 19, wherein

at least one of the first means for reflecting infrared radiation and the second means for reflecting infrared radiation consists of, in numerical order outward from the substrate, a first sublayer, a second sublayer including Ag, and a third sublayer;

the first sublayer includes a zinc oxide; and

the third sublayer includes a means for preventing the Ag in the second sublayer from corroding.

22. The coating according to claim 21, wherein the zinc oxide comprises nitrogen.

24. The coating according to claim 22, wherein

the first layer includes a layer of SiN_x, where 0<

x≦

1.34;

the fifth layer includes a layer of SiN_x, where 0<

x≦

1.34; and

the ninth layer includes a layer of SiN_x, where 0<

x≦

1.34.

25. The coating according to claim 24, wherein the first layer includes a layer of SiN_x, where x=1.34.

23. A low-emissivity coating on a transparent substrate, the coating comprising, in numerical order outward from the substrate,

a first layer including at least one layer selected from titanium oxide layers and silicon nitride layers;

a second layer including a zinc oxide;

a third layer including Ag;

a fourth layer consisting of a first fully oxidized Ni—

Cr alloy directly on the Ag of the third layer;

a fifth layer including at least one layer selected from titanium oxide layers and silicon nitride layers;

a sixth layer including a zinc oxide;

a seventh layer including Ag;

an eighth layer consisting of a second fully oxidized Ni—

Cr alloy directly on the Ag of the seventh layer; and

a ninth layer including silicon nitride.