Anti-reflective films

• US 5,935,716 A
• Filed: 02/17/1998
• Issued: 08/10/1999
• Est. Priority Date: 07/07/1997
• Status: Expired due to Term

• Current Assignee: Libbey-Owens-Ford Co. (Eaton Corporation PLC.)
• Original Assignee: Libbey-Owens-Ford Co. (Eaton Corporation PLC.)
• Inventors: Soubeyrand, Michel J., McCurdy, Richard J., Goodman, Ronald D.
• Primary Examiner(s): Speer, Timothy M.
• Application Number:
  US09/024,228
• Time in Patent Office: 539 Days
• Field of Search: 428/428, 428/432, 428/701, 428/702, 359/359, 359/586
• US Class Current: 428/428
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 17/3435 comprising a nitride, oxynitride, boronitride or carbonitride
• CPC Class Codes: C03C 2217/734 comprising an alternation of high and low refractive indexes
• CPC Class Codes: G02B 1/115 Multilayers
• CPC Class Codes: G02B 1/116 including electrically conducting layers

Abstract

An anti-reflective glass article including a glass substrate, a first coating of a metal oxide and a second coating of a metal oxide. The first coating of metal oxide is applied over the substrate. The refractive index of the first coating of metal oxide ranges from 1.8 to 2.6. The thickness of the first coating is greater than l/(4*n), wherein l equals a design wavelength in the visible spectrum and n equals the refractive index of said first coating of metal oxide. The second coating of metal oxide is applied over the first coating. The second coating of metal oxide has a refractive index of about 1.45 to about 1.6 and a thickness of less than l/4(n).

Claims

1. An anti-reflective glass article, comprising:

(a) a glass substrate,

(b) a first pyrolytic coating of a metal oxide applied over said substrate, said first coating of metal oxide having a refractive index of 1.8 to 2.6 and a thickness of greater than l/(4*n) wherein l equals a design wavelength in the visible spectrum and n equals the refractive index of said first coating of metal oxide; and

(c) a second pyrolytic coating of a metal oxide applied over said first coating, said second coating of metal oxide having a refractive index of about 1.45 to about 1.6 and a thickness of less than l/(4*n).

2. An anti-reflective glass article as recited in claim 1, wherein said first coating of metal oxide is a doped metal oxide.

3. An anti-reflective glass article as recited in claim 1, wherein said first coating is fluorine doped tin oxide having a refractive index of about 1.82, and said second coating is a silicon oxide having a refractive index of about 1.45.

4. An anti-reflective glass article as recited in claim 3, wherein said first coating is applied at a thickness of about 1000 angstroms, and said second coating of metal oxide is applied at a thickness of about 840 angstroms.

5. An anti-reflective glass article as recited in claim 4, wherein said article exhibits a neutral color in transmission defined in the CIELAB system having an a* value of about -1.76 and a b* value of about 1.88.

6. An anti-reflective glass article as recited in claim 4, wherein said article exhibits a reflected color as defined in the CIELAB system having an a* value of about 3.56 and a b* value of about -9.31.

7. An anti-reflective glass article as recited in claim 1, wherein said article exhibits a neutral color in transmission and reflectance as defined in the CIELAB system having an a* value from about 4 to about -6 and a b* value of about 4 to about -12.

8. An anti-reflective glass article as recited in claim 1, further comprising a barrier layer applied between said glass substrate and said first coating of metal oxide.

9. An anti-reflective glass article as recited in claim 8, wherein said barrier layer is SiO₂ having a thickness of about 100 angstroms.

10. An anti-reflective glass article as recited in claim 1, wherein said glass substrate is a float glass ribbon and said coatings are deposited pyrolytically onto said float glass ribbon.

11. An anti-reflective glass article as recited in claim 1, wherein said coated article exhibits a reflectance of less than 6%.

12. An anti-reflective glass article as recited in claim 1, wherein said coated article exhibits a reflectance of less than 5%.

13. An anti-reflective glass article as recited in claim 1, wherein said article further includes a polished back surface.

14. An anti-reflective glass article, comprising:

(a) a glass substrate,

(b) a first coating of an oxy-nitride applied over said substrate, said first coating having a refractive index of 1.8 to 2.6 and a thickness of greater than l/(4*n)wherein l equals a design wavelength in the visible spectrum and n equals the refractive index of said first coating of oxy-nitride; and

(c) a second coating of a metal oxide applied over said first coating, said second coating of metal oxide having a refractive index of about 1.45 to about 1.6 and a thickness of less than l/(4*n).

15. An anti-reflective glass article, comprising:

(a) a glass substrate,

(b) a first coating of silicon oxide applied over said substrate,

(c) a second coating of fluorine doped tin oxide applied over said first coating, said second coating of fluorine doped tin oxide having a refractive index of 1.8 to 2.6 and a thickness of greater than l/(4*n) wherein l equals a design wavelength in the visible spectrum and n equals the refractive index of said second coating of fluorine doped tin oxide; and

(d) a third coating of a silicon oxide applied over said second coating, said third coating of silicon oxide having a refractive index of about 1.45 to about 1.6 and a thickness of less than l/(4*n).

16. An anti-reflective glass article as recited in claim 15, wherein said article further includes a polished back surface.

17. An anti-reflective glass article as recited in claim 15, wherein said first coating of silicon oxide has a thickness of about 185 angstroms.

18. An anti-reflective glass article as recited in claim 15, wherein said second coating of fluorine doped tin oxide has a thickness of about 1025 angstroms.

19. An anti-reflective glass article as recited in claim 15, wherein said third coating of silicon oxide has a thickness of about 777 angstroms.

20. An anti-reflective glass article as recited in claim 15, wherein said article exhibits a neutral color in transmission defined in the CIELAB system having an a* value of about -1.9 and a b* value of about 2.4.

21. An anti-reflective glass article as recited in claim 15, wherein said article exhibits a neutral color in reflectance defined in the CIELAB system having an a* value of about 5.6 and a b* value of about 12.0.

22. An anti-reflective glass article, comprising:

(a) a glass substrate,

(b) a first coating of a metal oxide applied over said substrate, said first coating of metal oxide having a refractive index of 1.8 to 2.6 and a thickness of greater than l/(4*n) wherein l equals a design wavelength in the visible spectrum and n equals the refractive index of said first coating of metal oxide; and

(c) a second coating of a metal oxide applied over said first coating, said second coating of metal oxide having a refractive index of about 1.45 to about 1.6 and a thickness of less than l/(4*n), wherein n equals the refractive index of said second coating of metal oxide and said glass article exhibits a reflectance of less than 6% and a visible light transmittance of greater than 90%.