Method of making transparent articles utilizing protective layers for optical coatings

• US 6,770,321 B2
• Filed: 01/25/2002
• Issued: 08/03/2004
• Est. Priority Date: 01/25/2002
• Status: Expired due to Term

• Current Assignee: Cardinal CG Company (Cardinal Glass Industries Incorporated)
• Original Assignee: AFG Industries Incorporated (AGC, Inc.)
• Inventors: Maschwitz, Peter A., Hukari, Kyle W., Dannenberg, Rand D.
• Primary Examiner(s): CHEN, BRET P
• Application Number:
  US10/054,973
• Publication Number:
  US 20030143401A1
• Time in Patent Office: 921 Days
• Field of Search: 427/154, 427/164, 427/165, 427/255.394, 427/255.7, 427/166, 204/192.1
• US Class Current: 427/154
• CPC Class Codes: C03C 17/3435 comprising a nitride, oxynitride, boronitride or carbonitride
• CPC Class Codes: C03C 17/3441 comprising carbon, a carbide or oxycarbide
• 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 17/3634 one layer at least containing carbon, a carbide or oxycarbide
• CPC Class Codes: C03C 17/3644 the metal being silver
• CPC Class Codes: C03C 17/366 Low-emissivity or solar control coatings
• CPC Class Codes: C03C 2217/78 Coatings specially designed to be durable, e.g. scratch-resistant
• CPC Class Codes: C03C 2218/355 Temporary coating
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A method is provided for making transparent articles utilizing protective layers for optical coatings. An optical coating on a transparent substrate is provided with a temporary layer of carbon as protection during manufacturing against scratches and corrosive environments. When the optical coating and/or substrate are tempered in an atmosphere reactive to carbon, such as air, the layer of carbon is removed as a carbon-containing gas. For an optical coating with a brittle, glassy, outermost layer furthest from the substrate, additional protection is provided by a scratch propagation blocker layer between the outermost layer and the carbon protective layer.

Claims

1. A method of making a transparent article, the method comprising

forming a protective coating including a layer consisting essentially of carbon on an optical coating on a substrate;

heating the protective coating in a reactive atmosphere;

reacting the layer consisting essentially of carbon with the reactive atmosphere to form a carbon containing gas; and

removing the layer consisting essentially of carbon from the optical coating to form the transparent article.

2. The method according to claim 1, wherein the forming comprises vapor depositing the protective coating.

3. The method according to claim 2, wherein the vapor depositing comprises sputtering.

4. The method according to claim 1, wherein before the heating the layer consisting essentially of carbon is 1 nm to 10 nm thick.

5. The method according to claim 1, wherein the layer consisting essentially of carbon is doped with nitrogen.

6. The method according to claim 1, wherein the layer consisting essentially of carbon consists of carbon and unavoidable impurities.

7. The method according to claim 1, wherein the carbon in the layer consisting essentially of carbon comprises at least one form of carbon selected from the group consisting of diamond-like carbon and graphite.

8. The method according to claim 1, wherein the reactive atmosphere is an atmosphere containing oxygen.

9. The method according to claim 8, wherein the atmosphere containing oxygen is air.

10. The method according to claim 1, wherein the carbon containing gas comprises at least one compound selected from the group consisting of carbon monoxide and carbon dioxide.

11. The method according to claim 1, wherein the heating comprises raising a temperature of the protective coating to at least 400°

C.

12. The method according to claim 1, wherein the heating tempers the optical coating.

13. The method according to claim 1, wherein the heating tempers the substrate.

14. The method according to claim 1, wherein the substrate comprises a glass.

15. The method according to claim 14, wherein the glass is transparent to visible light.

16. The method according to claim 1, wherein the reacting removes all of the layer consisting essentially of carbon from the optical coating.

17. The method according to claim 1, wherein a number of scratches in the optical coating after the removing is no more than 110% of a number of scratches in the optical coating immediately before the forming.

18. The method according to claim 1, wherein the optical coating includes furthest from the substrate a homogeneous outermost layer comprising silicon nitride.

19. The method according to claim 18, wherein

the protective coating further includes a scratch propagation blocker layer between the layer consisting essentially of carbon and the outermost layer; and

the scratch propagation blocker layer is a homogeneous layer comprising a material selected from the group consisting of

Ti, Si, Zn, Sn, In, Zr, Al, Cr, Nb, Mo, Hf, Ta and W;

oxides of Ti, Si, Zn, Sn, In, Zr, Al, Cr, Nb, Mo, Hf, Ta and W;

nitrides of Ti, Si, Zn, Sn, In, Zr, Al, Cr, Nb, Mo, Hf, Ta and W; and

mixtures thereof.

20. The method according to claim 19, wherein the scratch propagation blocker layer consists of unavoidable impurities and a material selected from the group consisting of

Ti, Si, Zn, Sn, In, Zr, Al, Cr, Nb, Mo, Hf, Ta and W;

oxides of Ti, Si, Zn, Sn, In, Zr, Al, Cr, Nb, Mo, Hf, Ta and W;

nitrides of Ti, Si, Zn, Sn, In, Zr, Al, Cr, Nb, Mo, Hf, Ta and W; and

mixtures thereof.

21. The method according to claim 19, wherein the scratch propagation blocker layer has a thickness of from 2 to 8 nm.

22. A method of making a transparent article, the method comprising

providing a substrate having an optical coating including furthest from the substrate a homogeneous outermost layer comprising silicon nitride;

and

forming a scratch propagation blocker layer on the outermost layer, wherein

the scratch propagation blocker layer is a homogeneous layer comprising a material selected from the group consisting of

Ti, Si, Zn, Sn, In, Zr, Al, Cr, Nb, Mo, Hf, Ta and W;

oxides of Ti, Si, Zn, Sn, In, Zr, Al, Cr, Nb, Mo, Hf, Ta and W;

nitrides of Ti, Si, Zn, Sn, In, Zr, Al, Cr, Nb, Mo, Hf, Ta and W; and

mixtures thereof.

23. The method according to claim 22, wherein the outermost layer comprises amorphous silicon nitride.

24. The method according to claim 22, wherein the forming comprises vapor depositing the scratch propagation blocker layer on the outermost layer.

25. The method according to claim 22, wherein

the scratch propagation blocker layer comprises a material selected from the group consisting of TiO₂, SiO₂, ZnO, SnO₂, In₂O₃, ZrO₂, Al₂O₃, Cr₂O₃, Nb₂O₅, MoO₃, HfO₂, Ta₂O₅, WO₃ and mixtures thereof; and

the forming comprises

depositing on the outermost layer a metal, a metal suboxide or a metal subnitride diffusion barrier layer comprising at least one element selected from the group consisting of Ti, Si, Zn, Sn, In, Zr, Al, Cr, Nb, Mo, Hf, Ta and W;

heating the diffusion barrier layer in an atmosphere containing oxygen; and

reacting the diffusion barrier layer with the oxygen to form the scratch propagation blocker layer.

26. The method according to claim 25, wherein the diffusion barrier layer has a thickness of from 2 nm to 8 nm.

27. The method according to claim 25, wherein the atmosphere containing oxygen is air.

28. The method according to claim 25, wherein the heating comprises raising a temperature of the optical coating to at least 400°

C.

29. The method according to claim 25, wherein the heating tempers the optical coating.

30. The method according to claim 25, wherein the heating tempers the substrate.

31. The method according to claim 25, further comprising

depositing a layer consisting essentially of carbon on the diffusion barrier layer before heating the diffusion barrier layer;

and

reacting the layer consisting essentially of carbon with the oxygen to form a carbon containing gas.

32. The method according to claim 31, wherein the carbon containing gas comprises at least one compound selected from the group consisting of carbon monoxide and carbon dioxide.

33. The method according to claim 22, wherein the substrate comprises a glass.

34. The method according to claim 33, wherein the glass is transparent to visible light.