Dual silver layer Low-E glass coating system and insulating glass units made therefrom

• US 5,557,462 A
• Filed: 01/17/1995
• Issued: 09/17/1996
• Est. Priority Date: 01/17/1995
• 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., Larson, Steven L., Hartig, Klaus W.
• Primary Examiner(s): Dzierzynski, Paul M.
• Assistant Examiner(s): Schuberg, Darren E.
• Application Number:
  US08/373,085
• Time in Patent Office: 609 Days
• Field of Search: 359/359, 359/360, 359/580, 359/584, 359/585, 359/589, 359/588
• US Class Current: 359/585
• 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 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

Abstract

A sputter-coated glass layer system particularly useful in insulating glass units ("IGs"), which includes dual layers of silver separated by a layer of Si₃ N₄ having a thickness of about 700 Å-1,100 Å and further including an undercoat and an overcoat of Si₃ N₄ having thicknesses of about 300 Å-550 Å and about 350 Å-700 Å respectively, such that a glass so coated achieves normal emissivity values (E_n '"'"'s) of less than about 0.02-0.09 with good durability and very low reflectance.

Claims

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

a) a layer of Si₃ N₄ having a thickness of about 300 Å

-500 Å

;

b) a layer of nickel or nichrome having a thickness of about 7 Å

or less;

c) a layer of silver having a thickness of about 70 Å

-130 Å

;

d) a layer of nickel or nichrome having a thickness of about 7 Å

or less; and

e) a layer of Si₃ N₄ having a thickness of about 700 Å

-1,100 Å

;

f) a layer of nickel or nichrome having a thickness of about 7 Å

or less;

g) a layer of silver having a thickness of about 70 Å

-190 Å

, wherein said layer (g) is thicker than said layer (c);

h) a layer of nickel or nichrome having a thickness of about 7 Å

or less; and

i) a layer of Si₃ N₄ having a thickness of about 350 Å

-700 Å

;

wherein

when said glass substrate has a thickness of about 2 mm-6 mm, said coated glass substrate has a visible transmittance of about 70% or greater, a normal emissivity (E_n) of about 0.02 -0.09, a hemispherical emissivity (E_h) of about 0.03-0.12, a sheet resistance (R_s) of about 2-10 ohms/_sq. and having the following reflectance and color coordinates wherein the glass side characteristics are;

R_G Y, less than about 10

a_h is about -3 to +5

b_h is about 0 to -10

and wherein the film side characteristics are;

R_F Y, less than about 10

a_h is about -3 to +5

b_h is about 0 to -10

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

observer.

2. An article according to claim 1, wherein:

the thickness of layer (a) is about 350 Å

-450 Å

, the thickness of layer (c) is about 100 Å

-125 Å

, the thickness of layer (e) is greater than about 900 Å

-1,000 Å

, the thickness of layer (g) is about 140 Å

-170 Å

, and the thickness of layer (i) is about 400 Å

-500 Å

.

3. An article according to claim 2, wherein:

each of said layers (b), (d), (f), and (h) is less than about 7 Å

.

4. An article according to claim 3 having a visible transmittance of 72% -76%;

a normal emissivity (E_n) of about 0.03-0.06;

a hemispherical emissivity (E_h) of about 0.03 to 0.08, a sheet resistance of about 3-5, and having the following reflectance and color coordinates;

space="preserve" listing-type="tabular">______________________________________GLASS SIDER.sub.G Y, about 4-7a.sub.h, about +2.5 to +4.5b.sub.h, about -4 to -8FILM SIDER.sub.F Y, about 3-7a.sub.h, about 0.0 to +2.0b.sub.h, about 0.0 to -2.0______________________________________

5. An article according to claim 1, wherein said visible transmittance is about 72%-73%, said E_n is about 0.05-0.06, said E_h is about 0.060 and said R_s is about 3.0-4.0 ohms/_sq.

6. An article according to claim 5, wherein said layers have the following thicknesses:

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

)______________________________________ a about 400 b about 7 c about 110 d about 7 e about 950 f about 7 g about 155 h about 7 i about 450______________________________________

7. An article according to claim 5, having the following characteristics:

Ty, about 72.4

a_h, about -2.59

a_b, about -2.57

R_G Y, about 4.91

a_h, about +4.13

a_b, about -7.62

R_F Y, about 3.43

a_h, about +1.64

a_b, about -0.69

8. An article according to claim 1, wherein said layer system is chemically and mechanically durable.

9. An article according to claim 1, wherein said coated substrate when viewed from the glass side, the article has a color appearance within the range of neutral to slightly blue.

10. An insulating glass unit comprised of at least two substantially parallel, spaced sheets of glass wherein at least one sheet of glass is a glass article according to claims 1, 2, 3, 4, 5, 6, 7, 8, or 9.

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

12. An insulating glass unit according to claim 11, 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.

13. An insulating glass unit according to claim 12, wherein said unit is an insulating glass window, door or wall.

14. An insulating glass unit according to claim 11, wherein said layer system has the following thicknesses:

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

)______________________________________a about 350-450b about 7 or lessc about 100-125d about 7 or lesse about 900-1,000f about 7 or lessg about 140-170h about 7 or lessi about 400-500______________________________________

15. An insulating glass unit according to claim 14, wherein said layers have the following thicknesses:

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

)______________________________________a about 400b about 7c about 110d about 7e about 950f about 7g about 155h about 7i about 450______________________________________

wherein said layer system is located on the surface of the outside glass sheet within said insulating chamber and has the following approximate characteristics;

space="preserve" listing-type="tabular">______________________________________T.sub.visible 66R.sub.vis. outside 9R.sub.vis. inside 11T.sub.solar 36R.sub.solar 32Shading Coeff. 0.46S.H.G.C. 0.392U.sub.Winter 0.25U.sub.Summer 0.24E.sub.n 0.054E.sub.h 0.060Relative Heat Gain 94R.sub.s 3.39Ty 65.7 a* -3.2 b* +2.76R.sub.Y Y 8.8(outside) a* +1.81 b* -6.4R.sub.F Y(inside) a* +0.46 b* -1.1______________________________________

wherein said asterisk (*) indicates measurement by the Ill. C 2°

observer ASTM technique.

16. An insulating glass unit according to claim 14, wherein said layers have the following thicknesses:

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

)______________________________________a about 400b about 7c about 110d about 7e about 950f about 7g about 155h about 7i about 450______________________________________

wherein said layer system is located on the surface of the inside glass sheet within said insulating chamber and has the following approximate characteristics;

space="preserve" listing-type="tabular">______________________________________T.sub.visible 66R.sub.vis. outside 11R.sub.vis. inside 9T.sub.solar 36R.sub.solar 36Shading Coeff. 0.61S.H.G.C. 0.522U.sub.Winter 0.25U.sub.Summer 0.24E.sub.n 0.054E.sub.h 0.060Relative Heat Gain 125R.sub.s 3.39Ty 65.7 a* -3.2 b* +2.76R.sub.G Y 10.8(outside) a* +0.46 b* -1.1R.sub.F Y 8.8(inside) a* +1.81 b* -6.4______________________________________

wherein said asterisk (*) indicates measurement by the Ill. C 2°

observer ASTM technique.

17. An insulating glass unit according to claims 15 or 16, wherein said layer system is chemically and mechanically durable.