Neutral, high visible, durable low-e glass coating system and insulating glass units made therefrom

• US 5,770,321 A
• Filed: 03/22/1996
• Issued: 06/23/1998
• Est. Priority Date: 11/02/1995
• Status: Expired due to Term

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Lingle, Philip J., Hartig, Klaus W., Larson, Steve L.
• Primary Examiner(s): Zimmerman, John J.
• Application Number:
  US08/611,457
• Time in Patent Office: 823 Days
• Field of Search: 428/622, 428/623, 428/627, 428/630, 428/632, 428/666, 428/673, 428/680, 428/34, 428/46, 52/786.1
• US Class Current: 428/622
• CPC Class Codes: B32B 17/10174 Coatings of a metallic or dielectric material on a constituent layer of glass or polymer
• 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 17/3644 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: E06B 3/66304 Discrete spacing elements, e.g. for evacuated glazing units
• CPC Class Codes: Y10T 428/12542 More than one such component
• CPC Class Codes: Y10T 428/12549 Adjacent to each other
• CPC Class Codes: Y10T 428/12576 Boride, carbide or nitride component
• CPC Class Codes: Y10T 428/12597 Noncrystalline silica or noncrystalline plural-oxide component [e.g., glass, etc.]
• CPC Class Codes: Y10T 428/12611 Oxide-containing component
• CPC Class Codes: Y10T 428/12896 Ag-base component

Abstract

A sputter-coated layer system on a glass substrate particularly useful in insulating glass (IG) units, enables normal emissivity values (E_n) of 0.06 or less, good durability and neutral color. The layer system includes an undercoat of a transparent dielectric having an index of refraction between 2.5-2.6 at a wavelength of 550 nanometers, two layers of Si₃ N₄, and two layers of nichrome sandwiching a layer of silver to achieve its unique low-E, neutral color, non-mirrorlike solar management properties. An optional overcoat of a transparent dielectric material having an index of refraction of 2 at a wavelength of 550 nanometers may be provided.

Claims

1. A sputter-coated glass article comprised of a glass substrate having on a surface thereof, from the glass outwardly, a layer system including:

a) a layer of a transparent dielectric material having an index of refraction (n) of about 2.5-2.6 as measured at a wavelength of 550 nanometers;

b) a layer of Si₃ N₄ ;

c) a layer of nichrome;

d) a layer of silver;

e) a layer of nichrome; and

f) a layer of Si₃ N₄, and wherein

when said glass substrate has a thickness of about 2 mm-6 mm, and wherein said layers are of sufficient thicknesses such that said coated glass substrate has a normal emissivity (E_n) of about 0.06 or less, a hemispherical emissivity (E_h) of about 0.07 or less, a sheet resistance (R_s) of about 5.0 ohms/_sq. or less and having a substantially neutral visible reflected color when viewed from the glass side.

2. A sputter-coated glass article according to claim 1 wherein said dielectric material is selected from TiO₂, Bi₂ O₃, PbO, or mixtures thereof, said coated glass substrate has a visible transmittance of at least about 75%, and the chromium in said layers of nichrome is at least partially nitrided.

3. A sputter-coated glass article according to claim 1 wherein said glass article is heat treatable.

4. A sputter-coated glass article according to claims 1, 2 or 3 wherein the layers have about the following thicknesses:

space="preserve" listing-type="tabular">______________________________________ layer thickness (Å

) ______________________________________ a 100-400 b 20-120 c 7-50 d 75-225 e 7-30 f 50-600 ______________________________________

5. A sputter-coated glass article according to claim 4 wherein said undercoat layer (a) consists essentially of TiO₂.

6. A sputter-coated glass article according to claim 5 wherein said layers are substantially free of stainless steel.

7. A sputter-coated glass article according to claim 4 wherein the layers have about the following thicknesses:

space="preserve" listing-type="tabular">______________________________________ layer thickness (Å

) ______________________________________ a 200-250 b 40-60 c 7-30 d 150-180 e 7-15 f 400-500 ______________________________________

8. A sputter-coated article according to claim 4 wherein said undercoat layer has an index of refraction of about 2.52 at a wavelength of 550 namometers.

9. A sputter-coated article according to claim 8 wherein said undercoat consists essentially of TiO₂ and the layers have about the following thicknesses:

space="preserve" listing-type="tabular">______________________________________ layer thickness (Å

) ______________________________________ a 225 b 50 c 20 d 165 e 7 f 450 ______________________________________

and wherein the glass substrate having said layer system thereon has the following characteristics;

GLASS SIDE

R_G Y is about 13.1

a_h is about 1.4

b_h is about -4.0

FILM SIDE

R_f Y is about 8.6

a_h is about 4.7

b_h is about -12.2

wherein RY is the reflectance and a_h and b_h are the color coordinates as measured in Hunter units, Ill. C., 10°

observer, and wherein said layer system is mechanically and chemically durable and has a visible transmittance of about 76%.

10. A sputter-coated article according to claim 9 wherein said layer system is heat treatable.

11. A sputter-coated glass article according to claim 1 wherein said layer system consists essentially of said undercoat layer (a) and said layers (b)-(f) and said layers have about the following thicknesses:

space="preserve" listing-type="tabular">______________________________________ layer thickness (Å

) ______________________________________ a 100-400 b 20-120 c 7-50 d 75-225 e 7-30 f 50-600 ______________________________________

12. A sputter-coated article according to claim 11 wherein the layers have about the following thicknesses:

space="preserve" listing-type="tabular">______________________________________ layer thickness (Å

) ______________________________________ a 200-250 b 40-60 c 7-30 d 150-180 e 7-15 f 400-500 ______________________________________

13. A sputter-coated article according to claim 12 wherein said layer system is chemically and mechanically durable.

14. A sputter-coated article according to claim 13 wherein said layers have about the following thicknesses:

space="preserve" listing-type="tabular">______________________________________ layer thickness (Å

) ______________________________________ a 225 b 50 c 20 d 165 e 7 f 450 ______________________________________

and wherein said glass substrate having said layer system thereon has a visible transmittance greater than about 75%.

15. A sputter-coated article according to claim 14 wherein said glass substrate having said layer system thereon has the following characteristics:

GLASS SIDE

R_G Y is about 13.1

a_h is about 1.4

b_h is about -4.0

FILM SIDE

R_f Y is about 8.6

a_h is about 4.7

b_h is about -12.2

wherein RY is the reflectance and a_h and b_h are the color coordinates as measured in Hunter units, Ill. C., 10°

observer and has a visible transmittance of about 76%.

16. A sputter-coated article according to claim 15 wherein said layer system is heat treatable.

17. A sputter-coated article according to claim 1 which further includes an overcoat layer above said layer (f) of a transparent dielectric material.

18. A sputter-coated article according to claim 17 wherein said overcoat layer is selected from the group consisting of SnO₂, ZnO, In₂ O₃ and mixtures thereof.

19. A sputter-coated article according to claim 17 wherein said thickness of said overcoat layer is about 50 to 500 Å

, and has a refractive index (n) of about 1.8-2.2 at a wavelength of 550 nanometers, and wherein said layer (f) of Si₃ N₄ has a thickness of at least about 50 Å

.

20. An insulating glass unit comprised of at least two substantially parallel, spaced sheets of glass wherein at least one sheet of glass is a sputter-coated sheet of glass according to claim 1.

21. An insulating glass unit according to claim 20 wherein said two sheets of glass are sealed together at their peripheral edges thereby to define an insulating chamber therebetween, and wherein said layer system is located on a surface of one of said glass sheets within said insulating chamber, and the reflectance and color characteristics when viewed from outside are:

R_G Y about 14 to 20

a_h about -2 to +2

b_h about 0 to -10

and when viewed from the inside are;

R_f Y about 11 to 18

a_h about 0 to +4

b_h is about 0 to -10

and the visible transmittance is at least about 65%.

22. An insulating glass unit according to claim 21 wherein said unit is an insulating glass window, door or wall and the visible transmittance is at least about 69%.

23. An insulating glass unit comprised of at least two substantially parallel, spaced sheets of glass sealed together at their peripheral edges thereby to define an insulating chamber therebetween, wherein at least one of said glass sheets is a sputter-coated sheet of glass according to claim 4 wherein said layer system is located within said insulating chamber.

24. An insulating glass unit comprised of at least two substantially parallel, spaced sheets of glass and sealed together at their peripheral edges thereby to define an insulating chamber therebetween, wherein at least one of said glass sheets is a sputter-coated sheet of glass according to claim 5 wherein said layer system is located within said insulating chamber.

25. An insulating glass unit comprised of at least two substantially parallel, spaced sheets of glass heat sealed together at their peripheral edges and defining a substantially air-free insulating chamber therebetween, wherein at least one of said glass sheets is a sputter-coated sheet of glass according to claim 9, wherein said layer system is located within said insulating chamber.

26. An insulating glass unit comprised of at least two substantially parallel, spaced sheets of glass sealed together at their peripheral edges thereby to define an insulating chamber therebetween, wherein at least one of said glass sheets is a sputter-coated sheet of glass according to claim 10 wherein said layer system is located within said insulating chamber.

27. An insulating glass unit comprised of at least two substantially parallel, spaced sheets of glass and sealed together at their peripheral edges thereby to define an insulating chamber therebetween, wherein at least one of said glass sheets is a sputter-coated sheet of glass according to claim 13 wherein said layer system is located within said insulating chamber.

28. An insulating glass unit comprised of at least two substantially parallel, spaced sheets of glass heat sealed together at their peripheral edges and defining a substantially air-free insulating chamber therebetween, wherein at least one of said glass sheets is a sputter-coated sheet of glass according to claim 19, wherein said layer system is located within said insulating chamber.