Neutral, high visible, durable low-E glass coating system, insulating glass units made therefrom, and methods of making same

• US 6,059,909 A
• Filed: 02/25/1998
• Issued: 05/09/2000
• 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: Larson, Steve L., Lingle, Philip J., Hartig, Klaus W.
• Primary Examiner(s): Zimmerman, John J.
• Application Number:
  US09/030,361
• Time in Patent Office: 804 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, 156/109, 156/292, 65/58, 204/192.26, 204/192.27, 204/192.28, 204/192.29
• US Class Current: 156/109
• 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. In a method of making an insulating glass unit comprised of at least two sheets of glass sealed at their peripheral edges to each other thereby to define at least one insulating chamber therebetween, said method including the steps of spacing said glass sheets apart, heating said sheets at an elevated temperature, and sealing the peripheral edges of said sheets to each other at or above said elevated temperature, the improvement comprising using as at least one of said glass sheets, a glass sheet having on a surface thereof and extending outwardly therefrom, 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 sheet has a thickness of about 2 mm-6 mm and wherein said layers are of sufficient thicknesses such that said coated glass sheet 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. In a method according to claim 1 wherein said glass sheet having said layer system thereon is heat treatable.

3. In a method according to claim 1 wherein said layer (a) 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 sheet having said layer system thereon has the following characteristics;

space="preserve" listing-type="tabular">______________________________________ GLASS SIDE ______________________________________ R.sub.G Y is about 13.1 a.sub.h is about 1.4 b.sub.h is about -4.0 ______________________________________ FILM SIDE ______________________________________ R.sub.f Y is about 8.6 a.sub.h is about 4.7 b.sub.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%.

4. In a method according to claim 3 wherein said sheet having said layer system thereon is heat treatable.