Method for coating insulating film and glass substrate for image display using the same

• US 6,277,507 B1
• Filed: 06/21/1999
• Issued: 08/21/2001
• Est. Priority Date: 07/06/1998
• Status: Expired due to Fees

• Current Assignee: Nippon Sheet Glass Company Limited
• Original Assignee: Nippon Sheet Glass Company Limited
• Inventors: Anzaki, Toshiaki, Ogino, Etsuo
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): Miranda, Lymarie
• Application Number:
  US09/336,784
• Time in Patent Office: 792 Days
• Field of Search: 428/215, 428/216, 428/426, 428/428, 428/546, 428/698, 428/702
• US Class Current: 428/702
• 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: C23C 14/0036 Reactive sputtering
• CPC Class Codes: C23C 14/0652 Silicon nitride
• CPC Class Codes: C23C 14/0676 Oxynitrides
• CPC Class Codes: C23C 14/10 Glass or silica
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: Y10T 428/12014 having metal particles
• CPC Class Codes: Y10T 428/24967 Absolute thicknesses specified
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick

Abstract

A process for inexpensively producing an insulating substrate suitable for use in image displays fabricated through a high-temperature production step, such as plasma displays and field emission displays (FED). A multilayered insulating film of one member selected from SiO₂, a silicon oxynitride, and a silicon nitride is coated on a surface of a glass plate by reactive sputtering using one or more silicon targets in oxygen or/and nitrogen. The interface between layers in the multilayered insulating film functions to trap sodium ions thermally diffusing from the glass, whereby the amount of sodium ions which dissolve in the insulating film and reach the surface thereof is considerably reduced.

Claims

1. A method for coating a multilayer insulating film on a glass plate containing an alkali component, the method comprising coating an insulating film selected from the group consisting of SiO₂, a silicon oxynitride, and a silicon nitride on the glass plate by reactive sputtering using one or more silicon targets in oxygen or/and nitrogen in a vacuum apparatus in which an atmosphere having a reduced pressure can be adjusted, such that the multilayer insulating film is formed,

wherein one or more interfaces between layers of the insulating film function to trap the alkali component thermally diffusing from the e glass plate so that the concentration of alkali ions on the surface of the insulating film is about 0.2% or less of alkali ions in the glass plate.

2. The method for insulating-film deposition of claim 1, wherein the sputtering is reactive sputtering in which two silicon targets respectively disposed on two closely arranged cathodes are used, and a plasma discharge for which one of the cathodes is used as a negative electrode and the other is used as a positive electrode is generated alternately with a plasma discharge for which said one cathode is used as a positive electrode and said other is used as a negative electrode.

3. A glass substrate for image display, which comprises a glass plate containing an alkali component, and a multilayer insulation film coated on a surface of the glass plate,

wherein the insulating film is selected from group consisting of a SiO₂, a silicon oxynitride, and a silicon nitride and the insulating film is coated by reactive sputtering using one or more silicon targets in oxygen and/or nitrogen in a vacuum apparatus in which and atmosphere having a reduced pressure can be adjusted, such that a multilayer insulating film is formed,

and further wherein one or more interfaces between layers of the insulating film function to trap the alkali component thermally diffusing from the glass plate so that the concentration of alkali ions on the surface of the insulating film is about 0.2% or less of the concentration of alkali in the glass plate.

4. The glass substrate for image display as claimed in claim 3, wherein the concentration of alkali ions on the surface of the insulating film is from about 0.002% to about 0.2% of the concentration of alkali ions in the glass plate.

5. The glass substrate for image display as claimed in claim 3, wherein the insulating film has a thickness of 0.5 μ

m or larger.

6. The glass substrate for image display as claimed in claim 3, wherein the insulating film has a thickness of 2 μ

m or smaller.