Dispersion for preventing electrification antistatic film and image display device

• US 20040058148A1
• Filed: 03/10/2003
• Published: 03/25/2004
• Est. Priority Date: 09/11/2000
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Mikami, Akira, Tabata, Hitoshi, Ito, Takeo, Oyaizu, Tsuyoshi
• Granted Patent: US 6,992,431 B2
• Time in Patent Office: Days
• US Class Current: 428/328
• CPC Class Codes: C08K 3/22 of metals
• CPC Class Codes: C09D 7/61 inorganic
• CPC Class Codes: C09D 7/67 Particle size smaller than 100 nm
• CPC Class Codes: C09K 3/16 Anti-static materials
• CPC Class Codes: H01B 1/08 oxides
• CPC Class Codes: H01J 2229/8635 Antistatic shielding
• 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: Y10T 428/256 Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/259 Silicic material
• CPC Class Codes: Y10T 428/2995 Silane, siloxane or silicone coating

Abstract

This dispersion for preventing electrification contains as a primary component high-resistance fine particles having a specific resistivity of 10⁶ to 10⁹Ω·cm. This dispersion is applied by a simple and easy method such as spray coating or brushing and baked to obtain an antistatic film having a reduced dependency of a resistance value on a thickness of a film and environments and having stable antistatic properties.

The high-resistance fine particle is fine particle which is composed of antimony pentoxide (Sb₂O₅) having a pyrochlore crystal structure or has a core layer which is composed of at least one semiconducting substance selected from SnO₂, In₂O₃, Sb₂O₅ and ZnO₂ and a covering layer which is composed of at least one insulating substance selected from SiO₂, TiO₂, Al₂O₃ and ZrO₂.

An image display device which has such an antistatic film formed on the surface of an insulating member in a vacuum envelope is free from deterioration of display characteristics caused by a change of the track of electrons emitted by the application of voltage, a spark in a tube or a leakage current, and exhibits stable and good display characteristics.

Claims

1. A dispersion for preventing electrification, comprising high-resistance fine particles having a specific resistivity of 10⁶ to 10⁹Ω

·

cm as a primary component.

2. The dispersion for preventing electrification as set forth in claim 1, wherein the high-resistance fine particle is composed of antimony pentoxide (Sb₂O₅) having a pyrochlore crystal structure.

3. The dispersion for preventing electrification as set forth in claim 1, wherein the high-resistance fine particle includes a core layer which is composed of at least one semiconducting substance selected from SnO₂, In₂O₃, Sb₂O₅ and ZnO₂ and a covering layer which is formed on the core layer and composed of at least one insulating substance selected from SiO₂, TiO₂, Al₂O₃ and ZrO₂.

4. The dispersion for preventing electrification as set forth in claim 1, wherein the high-resistance fine particle has a particle diameter of 5 to 100 nm.

5. An antistatic film, which is formed on the surface of an insulating substrate held in a vacuum, comprising mainly high-resistance fine particles having a specific resistivity of 10⁶ to 10⁹ Ω

·

cm.

6. The antistatic film as set forth in claim 5, wherein the high-resistance fine particle is composed of antimony pentoxide (Sb₂O₅) having a pyrochlore crystal structure.

7. The antistatic film as set forth in claim 5, wherein the high-resistance fine particle includes a core layer which is composed of at least one semiconducting substance selected from SnO₂, In₂O₃, Sb₂O₅ and ZnO₂ and a covering layer which is formed on the core layer and composed of at least one insulating substance selected from SiO₂, TiO₂, Al₂O₃ and ZrO₂.

8. The antistatic film as set forth in claim 5, wherein the high-resistance fine particle has a particle diameter of 5 to 100 nm.

9. An image display device, comprising a vacuum envelope which has a light transmissible panel and its inside held vacuum, a phosphor layer which is formed on the inside surface of the light transmissible panel, an electron emission means and an insulating member which are disposed within the vacuum envelope, wherein the insulating member has the antistatic film as set forth in claim 5 on the surface thereof.

10. The image display device as set forth in claim 9, wherein the antistatic film has a thickness of 50 to 1000 nm.

11. The image display device as set forth in claim 9, wherein the antistatic film is formed to cover 20% or more of the surface area of the insulating member.