Processes for forming transparent substrate with diffuser surface

• US 6,440,491 B1
• Filed: 06/30/2000
• Issued: 08/27/2002
• Est. Priority Date: 07/29/1994
• Status: Expired due to Term

• Current Assignee: TPK Touch Solutions (Xiamen) Inc. (TPK Holding Co., Ltd.)
• Original Assignee: Donnelly Corporation (Magna International Incorporated)
• Inventors: Varaprasad, Desaraju V., Dornan, Craig A., Getz, Catherine A.
• Primary Examiner(s): CAMERON, ERMA C
• Application Number:
  US09/607,216
• Time in Patent Office: 788 Days
• Field of Search: 427/387, 427/164, 427/165, 427/168, 427/169, 427/407.2
• US Class Current: 427/168
• CPC Class Codes: C03C 17/25 by deposition from the liquid phase
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/211 SnO2
• CPC Class Codes: C03C 2217/216 ZnO
• CPC Class Codes: C03C 2217/231 In2O3/SnO2
• CPC Class Codes: C03C 2217/24 Doped oxides
• CPC Class Codes: C03C 2218/11 from solutions or suspensions
• CPC Class Codes: H01J 29/868 Screens covering the input or output face of the vessel, e.g. transparent anti-static coatings, X-ray absorbing layers
• CPC Class Codes: H01J 29/896 Anti-reflection means, e.g. eliminating glare due to ambient light

Abstract

Processes for making a transparent substrate having a glare reducing diffuser surface coating on its outer surface are disclosed to provide a faceplate such as for attachment to a screen for a cathode ray tube or other display device. Preferably, the coating has a thickness of less than about 3 microns and/or a gloss less than about 80 gloss units. The method includes spraying a precursor solution onto the substrate to form a preliminary coating, at least partially densifying that preliminary coating, spraying another coating of precursor solution onto the preliminary coating, and firing the coating to form a diffuser surface coating. Alternately, a precursor solution of an inorganic metal oxide dissolved in an organic solvent is sprayed on the substrate and fired at a temperature within the range of from about 250° C. to about 600° C. to form the diffuser surface coating.

Claims

1. A method of forming a diffuser coating on a transparent substrate, said method comprising:

spraying at least one layer of a precursor solution onto a transparent substrate to form a preliminary coating;

at least partially densifying said preliminary coating;

spraying a further layer of a precursor solution onto said preliminary coating; and

firing said preliminary coating and said further layer to form a diffuser surface coating on said substrate;

said method including at least one of a) forming said coating to have a gloss reading less than about 80 gloss units, b) forming said coating to have a resolution of at least 3 lines per millimeter, c) forming said coating to have a thickness of less than about 3 microns, and d) firing said preliminary coating and said further layer at a temperature in the range of from about 250°

C. to about 600°

C.

2. The method of claim 1 including forming said diffuser surface coating to have a gloss reading in the range of about 30 to 80 gloss units and a resolution in the range of about 3 lines to about 15 lines per millimeter.

5. The method of claim 1 further comprising bending said substrate having said diffuser surface coating thereon.

6. The method of claim 1 including forming said diffuser surface coating to have a resolution in the range of about 4 to about 12 lines per millimeter.

7. The method of claim 1 including forming said diffuser surface coating to have a gloss reading in the range of about 40 to about 70 gloss units.

8. The method of claim 1 wherein said diffuser surface coating has a thickness of less than about 3 microns.

9. The method of claim 1 wherein said precursor solution comprises a single metal oxide precursor.

10. The method of claim 1 wherein said precursor solution comprises a silica precursor.

11. The method of claim 1 wherein said firing is performed by heating said preliminary coating and said further layer to a temperature in the range of from about 250°

C. to about 600°

C.

12. The method of claim 11 wherein said firing is performed by heating said preliminary coating and said further layer to a temperature in the range of from about 350°

C. to about 550°

C.

13. The method of claim 12 wherein said firing is performed by heating said preliminary coating and said further layer to a temperature in the range of from about 500°

C. to about 520°

C.

14. The method of claim 11 wherein said firing is performed by heating said preliminary coating and said further layer for a time period of from about 3 minutes to about 3 hours.

15. The method of claim 1 wherein said partial densification of said preliminary coating is performed by exposure to infrared heating.

21. The method of claim 1 further comprising coating said transparent substrate with a transparent conductor coating prior to forming said preliminary coating and said further layer of precursor solution.

22. The method of claim 21 wherein said transparent conductor coating is selected from the group consisting of indium tin oxide, tin oxide, doped tin oxide, and doped zinc oxide.

3. A method of forming a diffuser coating on a transparent substrate, said method comprising:

spraying at least one layer of a metal oxide precursor solution onto a transparent substrate to form a preliminary coating;

at least partially densifying said preliminary coating;

spraying a further layer of a metal oxide precursor solution onto said preliminary coating; and

firing said preliminary coating and said further layer at a temperature in the range of from about 250°

C. to about 600°

C. to form a diffuser surface coating on said transparent substrate having a thickness of less than about 3 microns, a gloss reading in the range of about 30 to about 80 gloss units, and a resolution in the range of about 3 lines to about 15 lines per millimeter; and

overcoating said diffuser surface coating on said transparent substrate with a transparent conductor coating.

4. The method of claim 3 wherein said transparent conductor coating is selected from the group consisting of indium tin oxide, tin oxide, doped tin oxide, and doped zinc oxide.

16. A method of forming a diffuser coating on a transparent substrate, said method comprising:

providing a precursor solution comprising a precursor of an metal oxide dissolved in an organic solvent;

spraying at least one layer of said precursor solution onto said transparent substrate; and

firing said at least one layer at a temperature within the range of from about 250°

C. to about 600°

C. to form a diffuser surface coating having a thickness less than about 3 microns, a gloss reading of about 30 to about 80 gloss units, and a resolution in the range of about 3 lines to about 15 lines per millimeter.

17. The method of claim 16 wherein said precursor is selected from the group consisting of one or more metal alkoxides, metal halides, metal oxyhalides, metal acetates, metal peroxyesters, metal nitrates, and combinations thereof.

18. The method of claim 16 wherein said spraying of said at least one layer is performed while the temperature of said precursor solution and said substrate is at about ambient temperature.

19. The method of claim 16 wherein said spraying of said at least one layer is performed at a relative humidity of from about 25% RH to about 60% RH.

20. The method of claim 16 wherein said spraying of said at least one layer is performed utilizing an average spray discharge rate of from about 0.01 liters per minute to about 1.0 liters per minute.

23. The method of claim 16 further comprising overcoating said diffuser surface coating on said transparent substrate with a transparent conductor coating.

24. The method of claim 23 wherein said transparent conductor coating is selected from the group consisting of indium tin oxide, tin oxide, doped tin oxide, and doped zinc oxide.

25. The method of claim 16 further comprising coating said transparent substrate with a transparent conductor coating prior to spraying said at least one layer of said precursor solution.

26. The method of claim 25 wherein said transparent conductor coating is selected from the group consisting of indium tin oxide, tin oxide, doped tin oxide, and doped zinc oxide.