Low-e coating with high visible transmission

• US 6,830,817 B2
• Filed: 12/21/2001
• Issued: 12/14/2004
• Est. Priority Date: 12/21/2001
• Status: Expired due to Fees

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Stachowiak, Grzegorz
• Primary Examiner(s): Morris, Terrel
• Assistant Examiner(s): Piziali, Andrew T
• Application Number:
  US10/024,613
• Publication Number:
  US 20030170466A1
• Time in Patent Office: 1,089 Days
• Field of Search: 428/426, 428/432, 428/448, 428/450, 428/469, 428/472, 428/697, 428/698, 428/699, 428/701, 428/702, 428/704
• US Class Current: 428/432
• 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 2217/73 Anti-reflective coatings with specific characteristics
• CPC Class Codes: C03C 2217/734 comprising an alternation of high and low refractive indexes

Abstract

Coated articles are provided with an anti-reflection system(s) which enables high visible transmission and/or low visible reflection. Neutral color is also achievable in certain example embodiments. In certain example embodiments, the anti-reflection system(s) is used in conjunction with a double silver (Ag) layer stack which provides low sheet resistance and/or emissivity.

Claims

1. A coated article including a coating supported by a glass substrate, the coating comprising:

top, middle and bottom dielectric coating portions having effective or average indices of refraction n_T, n_M and n_B, respectively;

first and second infrared (IR) reflecting layers comprising silver (Ag), wherein the first IR reflecting layer comprising Ag is located between the bottom and middle dielectric coating portions, and the second IR reflecting layer comprising Ag is located between the middle and top dielectric coating portions, and wherein the top, middle and bottom dielectric coating portions do not include the IR reflecting layers and also do not include contact layers which contact the IR reflecting layers;

the bottom dielectric coating portion comprising a first dielectric layer comprising titanium oxide provided between the first IR reflecting layer and the glass substrate;

the middle dielectric coating portion comprising a second dielectric layer having an index of refraction 1.8<

=n<

=2.2 provided between the first and second IR reflecting layers, wherein the second dielectric layer has an index of refraction n less than the index of refraction n of the first dielectric layer;

the top dielectric coating portion comprising a third dielectric layer comprising titanium oxide provided over the first and second IR reflecting layers and a fourth dielectric layer comprising silicon oxide provided over the third dielectric layer comprising titanium oxide;

wherein the coated article has a visible transmission of at least 70%; and

wherein the average or effective indices of refraction n_T, n_M and n_B of the top, middle and bottom dielectric coating portions respectively have values so that n_T<

n_M<

n_B.

2. The coated article of claim 1, wherein the second dielectric layer comprises tin oxide.

3. The coated article of claim 1, the middle dielectric coating portion further comprising another dielectric layer comprising titanium oxide located between the first and second IR reflecting layers.

4. The coated article of claim 3, wherein the another dielectric layer comprising titanium oxide is located under the second dielectric layer.

5. The coated article of claim 3, the top dielectric coating portion further comprising another dielectric layer comprising tin oxide located between the third dielectric layer comprising titanium oxide and the fourth dielectric layer comprising silicon oxide.

6. The coated article of claim 1, wherein each of the first and second IR reflecting layers comprising Ag is sandwiched between and contacts a pair of contact layers, and wherein at least one of the contact layers adjacent each IR reflecting layer comprises at least one of NiCr, an oxide of NiCr, and a nitride of NiCr.

7. The coated article of claim 3, the bottom electric coating portion further comprising another dielectric layer comprising silicon nitride located between the first dielectric layer comprising titanium oxide and the first IR reflecting layer comprising Ag.

8. The coated article of claim 1, wherein the first dielectric layer comprising titanium oxide includes TiO₂, and wherein the silicon oxide comprises SiO₂.

9. The coated article of claim 3, wherein the coated article is characterized by a visible transmission of at least 75%, a sheet resistance (R_S) of no greater than 10 ohms/square, and a glass side visible reflectance <

=9%.

10. The coated article of claim 3, wherein the coated article has a visible transmission of at least 76.5%.

11. An IG window unit comprising the coated article of claim 1.

12. A coated article including a coating supported by a glass substrate, the coating comprising:

top, middle and bottom dielectric coating portions having effective or average indices of refraction n_T, n_M and n_B, respectively;

first and second infrared (IR) reflecting layers each comprising at least one of silver (Ag) and gold (Au), wherein the first IR reflecting layer is located between the bottom and middle dielectric coating portions, and the second IR reflecting layer is located between the middle and top dielectric coating portions, and wherein the top, middle and bottom dielectric coating portions do not include the IR reflecting layers and also do not include contact layers which contact the IR reflecting layers;

the bottom dielectric coating portion comprising a first dielectric layer comprising titanium oxide provided between the first IR reflecting layer and the glass substrate;

the middle dielectric coating portion comprising a second dielectric layer comprising titanium oxide provided between the first and second IR reflecting layers and a third dielectric layer having an index of refraction 1.8<

=n<

=2.2 provided between the first and second IR reflecting layers, wherein the third dielectric layer has an index of refraction n less than the index of refraction n of at least one of the first and second dielectric layers;

the top dielectric coating portion comprising a fourth dielectric layer comprising silicon oxide provided over the first and second IR reflecting layers;

wherein the coated article has a visible transmission of at least 70%; and

wherein the average or effective indices of refraction n_T, n_M and n_B of the top, middle and bottom dielectric coating portions respectively have values so that n_T<

n_M<

n_B.

13. The coated article of claim 12, wherein the third dielectric layer comprises tin oxide.

14. The coated article of claim 12, the top dielectric coating portion further comprising another dielectric layer comprising silicon nitride provided between the second IR reflecting layer and the fourth dielectric layer comprising silicon oxide.

15. The coated article of claim 12, the top dielectric coating portion further comprising another dielectric layer comprising titanium oxide provided between the second IR reflecting layer and the fourth dielectric layer comprising silicon oxide.

16. The coated article of claim 12, the top dielectric coating portion further comprising another dielectric layer comprising tin oxide provided between the second IR reflecting layer and the fourth dielectric layer comprising silicon oxide.

17. The coated article of claim 12, the bottom dielectric coating portion further comprising another dielectric layer comprising silicon nitride located between the first dielectric layer comprising titanium oxide and the first IR reflecting layer.

18. The coated article of claim 12, wherein each of the first and second IR reflecting layers comprises Ag and is sandwiched between and contacts a pair of contact layers, and wherein at least one of the contact layers adjacent each IR reflecting layer comprises at least one of NiCr, an oxide of NiCr, and a nitride of NiCr.

19. The coated article of claim 12, wherein the first and second dielectric layers comprising titanium oxide each include TiO₂.

20. The coated article of claim 12, wherein the coated article is further characterized by a visible transmission of at least 75%, a sheet resistance (R_S) of no greater than 10 ohms/square, and a glass side visible reflectance <

=9%.

21. The coated article of claim 20, wherein the coated article has a visible transmission of at least 76.5%.

22. A window comprising the coated article of claim 12.

23. A coated article including a coating supported by a glass substrate, the coating comprising:

top, middle and bottom dielectric coating portions having effective or average indices of refraction n_T, n_M and n_B, respectively;

first and second infrared (IR) reflecting layers each comprising at least one of silver (Ag) and gold (Au), wherein the first IR reflecting layer is located between the bottom and middle dielectric coating portions, and the second IR reflecting layer is located between the middle and top dielectric coating portions;

the bottom dielectric coating portion comprising a first dielectric layer comprising titanium oxide provided between the first IR reflecting layer and the glass substrate;

the middle dielectric coating portion comprising a second dielectric layer comprising titanium oxide provided between the first and second IR reflecting layers, and a third dielectric layer having an index of refraction 1.8<

=n<

=2.2 provided between the first and second IR reflecting layers, wherein the third dielectric layer has an index of refraction n less than the index of refraction n of at least one of the first and second dielectric layers;

the top dielectric coating portion comprising a fourth dielectric layer comprising at least one of silicon nitride and silicon oxynitride provided over the first and second IR reflecting layers;

wherein the coated article has a visible transmission of at least 70%; and

wherein the average or effective indices of refraction n_T, n_M and n_B of the top, middle and bottom dielectric coating portions respectively have values so that n_T<

n_M<

n_B.

24. The coated article of claim 23, wherein the fourth dielectric layer comprises silicon oxynitride.

25. The coated article of claim 24, wherein the fourth dielectric layer comprising silicon oxynitride is at least one of oxidation graded and nitrogen graded, so that an index of refraction n of the fourth dielectric layer comprising silicon oxynitride changes from a first value in a first portion of the fourth dielectric layer a smaller second value in a second portion of the fourth dielectric layer, wherein the second portion of the fourth dielectric layer comprising silicon oxynitride with the smaller index of refraction n is further from the IR reflecting layers than is the first portion of the fourth dielectric layer.