Non-glaze coating for a cathode ray tube

• US 4,694,218 A
• Filed: 01/13/1986
• Issued: 09/15/1987
• Est. Priority Date: 05/04/1984
• Status: Expired due to Fees

• Current Assignee: Cotek Company
• Original Assignee: Cotek Company
• Inventors: Chao, Paul
• Primary Examiner(s): DEMEO, PALMER
• Application Number:
  US06/817,867
• Time in Patent Office: 610 Days
• Field of Search: 313/478, 313/474, 428/428, 427/160
• US Class Current: 313/478
• CPC Class Codes: C03C 17/25 by deposition from the liquid phase
• CPC Class Codes: C03C 2217/212 TiO2
• CPC Class Codes: C03C 2217/213 SiO2
• CPC Class Codes: C03C 2217/22 ZrO2
• CPC Class Codes: C03C 2217/23 Mixtures
• CPC Class Codes: C03C 2218/113 by sol-gel processes
• CPC Class Codes: G02B 1/111 using layers comprising organic materials
• CPC Class Codes: H01J 29/896 Anti-reflection means, e.g. eliminating glare due to ambient light

Abstract

A coating for reducing specular reflection on optical glass screens comprises a partially hydrolized metal alkoxide polymer. These alkoxides have the general formula M(OR)₄ where M is selected from the group consisting of silicon, titanium and zirconium where R is alkyl with 1 to 6 carbon. The equivalent titanium and/or zirconium oxides is about 15% of total solids by weight. A presently preferred coating mixture is prepared by dissolving tetraethyl orthosilicate in alcohol, at an elevated temperature; gradually adding a mixture of nitric acid and water; gradually adding titanium butoxide and/or zirconium n-propoxide; and, adding and mixing additional water and alcohol. The coating is applied by a method comprising the steps of cleaning the surface of the optical glass screen; preheating the glass screen; coating the solution onto the glass screen; and, baking the glass screen and solution, at a temperature high enough to drive off the solvent and bond the coating mixture to the glass surface.

Claims

1. In a cathode ray tube having an optical glass screen, the improvement wherein said optical glass screen is coated exteriorly with a mixture of a solid of partially hydrolized metal alkoxides, the metal alkoxides having the general formula M(OR)₄ where M is selected form the group consisting of silicon, titanium and zirconium, wherein the metal alkoxides comprise SiO₂ and ZrO₂ and wherein the SiO₂ forms approximately 85% of the solid mixture by weight.

2. A cathode ray tube according to claim 1, wherein the metal alkoxides comprise equivalent titanium and zirconium oxides, the equivalent titanium and zirconium oxides forming approximately 10% of the solid mixture, by molar ratio and wherein the SiO₂ forms approxiamtely 90% of the solid mixture, by molar weight.

3. A cathode ray tube according to claim 1, wherein the metal alkoxides comprise equivalent titanium and zirconium oxides, the equivalent titanium and zirconium oxides forming approximately 15% of the solid mixture, by weight.

4. A cathode ray tube according to claim 1, and a solution, the solution comprising an alcohol and water, the water having a molar ration of 1.3 to 1.6 to SiO₂, the water being used for hydrolysis of M(OR)₄.

5. A cathode ray tube according to claim 4 wherein the solid mixture comprises between 10% and 20% by weight and the solution comprises between 80% and 90% by weight.