Transparent Conductive Formed Article for a Touch Panel and Touch Panel

• US 20080029292A1
• Filed: 04/19/2005
• Published: 02/07/2008
• Est. Priority Date: 04/20/2004
• Status: Active Grant

• Current Assignee: Takiron Company Limited (Itochu Corporation)
• Original Assignee: Takiron Company Limited (Itochu Corporation)
• Inventors: Ito, Hidemi, Takayama, Ryuji, Nakanishi, Junichi, Masago, Hitoshi
• Granted Patent: US 7,956,287 B2
• Time in Patent Office: Days
• US Class Current: 174/126.4
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

There are provided a transparent conductive formed article for a touch panel, having a conductive layer which is excellent in abrasion resistance and elasticity, shows little change in surface resistivity at the time of the use of a touch panel, and does not change hues of the transmitting light, and a touch panel that use the same.

The transparent conductive formed article for a touch panel is prepared by forming a transparent conductive layer 12 comprising ultra fine conductive fibers 4 on at least one side of a transparent substrate 11, and the touch panel is prepared using the aforementioned transparent conductive formed article as an electrode. The ultra fine conductive fibers of the transparent conductive layer 12 are dispersed without aggregation and dispersed and contacted with one another in a state in which said fibers are separated one by one or in a state in which a bundle formed by the gathering of two or more fibers is separated from other bundles. Accordingly, the surface resistivity can be easily controlled to 10⁴Ω/□ or less, and the light transmittance of the conductive layer at a wavelength of 550 nm to 75% or more.

Claims

1. A transparent conductive formed article for a touch panel, wherein a transparent conductive layer comprising ultra fine conductive fibers is formed on at least one side of a transparent substrate.

4. The transparent conductive formed article for a touch panel according to any one of claim 1 to claim 3, wherein the aforementioned ultra fine conductive fibers are carbon nanotubes.

5. The transparent conductive formed article for a touch panel according to any one of claim 1 to claim 4, wherein the aforementioned ultra fine conductive fibers are multi-wall carbon nanotubes which are dispersed and contacted with one another in a state of separated individual fibers.

6. The transparent conductive formed article for a touch panel according to any one of claim 1 to claim 4, wherein the aforementioned ultra fine conductive fibers are single-wall carbon nanotubes which are dispersed and contacted with one another in the form of individual bundles in which each bundle is formed by the gathering of two or more fibers.

7. The transparent conductive formed article for a touch panel according to any one of claim 1 to claim 4, wherein the aforementioned ultra fine conductive fibers are double or triple wall carbon nanotubes which are dispersed and contacted with one another in the form of individual bundles in which each bundle is formed by the gathering of two or more fibers.

8. The transparent conductive formed article for a touch panel according to any one of claim 1 to claim 7, wherein the aforementioned conductive layer has a surface resistivity of 10⁴Ω

/□

or less.

9. The transparent conductive formed article for a touch panel according to any one of claim 1 to claim 7, wherein the aforementioned conductive layer has a surface resistivity of 10⁴Ω

/□

or less, and the light transmittance at a wavelength of 550 nm is 75% or more.

10. The transparent conductive formed article for a touch panel according to any one of claim 1 to claim 9, wherein surface resistivity of the aforementioned conductive layer is increased by a factor of 1.3 or less after its bending at a curvature radius of 3 mm.

11. The transparent conductive formed article for a touch panel according to any one of claim 1 to claim 10, wherein both of the transmission hues a* and b* of the transparent conductive formed article in the L*a*b* color system established by JIS Z8729 are within the range from −

2.5 to 2.5.

12. A touch panel, wherein the transparent conductive formed article described in any one of claim 1 to claim 11 is used as an electrode.

2. A transparent conductive formed article for a touch panel, wherein a transparent conductive layer comprising ultra fine conductive fibers is formed on at least one side of a transparent substrate, and wherein the aforementioned ultra fine conductive fibers are dispersed and contacted with one another without aggregation.

3. A transparent conductive formed article for a touch panel, wherein a transparent conductive layer comprising ultra fine conductive fibers is formed on at least one side of a transparent substrate, and wherein the aforementioned ultra fine conductive fibers are dispersed and contacted with one another, in a state of separated individual fibers or in a state under which a bundle formed by the gathering of two or more fibers is separated from other bundles.