Transparent conductive films containing carbon nanotubes and touch panel

• US 8,741,434 B2
• Filed: 10/07/2008
• Issued: 06/03/2014
• Est. Priority Date: 08/14/2008
• Status: Expired due to Fees

• Current Assignee: Korea Electrotechnology Research Institute
• Original Assignee: Korea Electrotechnology Research Institute
• Inventors: Han, Joong Tark, Lee, Geon Woong, Jeong, Hee Jin, Woo, Jong Seok
• Primary Examiner(s): Shosho, Callie
• Assistant Examiner(s): Fung, Coris
• Application Number:
  US12/247,005
• Publication Number:
  US 20100040887A1
• Time in Patent Office: 2,065 Days
• Field of Search: None
• US Class Current: 428/411.1
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: C08K 3/34 Silicon-containing compounds
• CPC Class Codes: C08K 7/06 Elements
• CPC Class Codes: C09D 5/24 Electrically-conducting paints conductive materials H01B1/00
• CPC Class Codes: C09D 7/62 modified by treatment with other compounds
• CPC Class Codes: C09D 7/70 characterised by shape, e.g. fibres, flakes or microspheres
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: H10K 85/221 Carbon nanotubes
• CPC Class Codes: Y10T 428/29 Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31507 Of polycarbonate

Abstract

Disclosed herein is a transparent conductive polycarbonate film coated with carbon nanotubes, including a transparent conductive layer formed by applying a mixed solution of carbon nanotubes and a binder on one side or both sides of a transparent polycarbonate film, and a touch panel using the transparent conductive polycarbonate film as a lower transparent electrode. The present invention provides a transparent conductive polycarbonate film coated with a mixed solution of carbon nanotubes and a binder, by which a touch panel having high transmissivity can be manufactured by directly forming a transparent conductive layer on a polycarbonate film used as a protective film of a liquid crystal display using carbon nanotubes, without using a polyethylene terephthalate (PET) substrate used for a transparent electrode of a conventional touch panel, by which the production cost of the touch panel can be decreased, and by which a thin touch panel can be manufactured.

Claims

1. A transparent conductive polycarbonate film, comprising a multi-layered transparent conductive layer formed on at least one side of a transparent polycarbonate film, wherein the multi-layered transparent conductive layer comprises an adhesive layer disposed on one surface of the transparent polycarbonate film, a protective layer, and a primary conductive layer interposed between the adhesive layer and the protective layer, wherein the primary conductive layer, the adhesive layer and the protective layer each each comprise double-wall or multi-wall carbon nanotubes with carboxylic groups introduced at the end and surface of the carbon nanotubes and a binder, and wherein the primary conductive layer, the adhesive layer and the protective layer have different amount of binder mixed therein.

2. The transparent conductive polycarbonate film of claim 1, wherein the transparent conductive polycarbonate film has a surface resistance of 1×

10³ Ω

/sq or less and a transmissivity of 70% or more in a wavelength of 540˜

560 nm.

3. The transparent conductive polycarbonate film of claim 2, wherein an amount of the binder included in the adhesive layer is 20˜

99.9 parts by weight based on 100 parts by weight of a mixture of the carbon nanotubes and binder, an amount of the binder included in the primary conductive layer is 0.1˜

50 parts by weight based on 100 parts by weight of the mixture of the carbon nanotubes and binder, and an amount of the binder included in the protective layer is 20˜

99.9 parts by weight based on 100 parts by weight of the mixture of the carbon nanotubes and binder, and wherein the binder is selected from the group consisting of photo-curable resins, silane compounds, titanium compounds, copolymers, self-assembled resins, and combinations thereof.

4. A touch panel, comprising:

a transparent polycarbonate substrate for protecting a directly adjacent liquid crystal display screen;

a lower transparent electrode formed on the transparent polycarbonate substrate;

an upper transparent electrode; and

a spacer interposed between the lower transparent electrode and the upper transparent electrode, wherein the lower transparent electrode is a multi-layered transparent conductive layer including an adhesive layer, a protective layer and a primary conductive layer interposed between the adhesive layer and the protective layer, in which each of the adhesive layer, the protective layer and the primary conductive layer comprises carbon nanotubes with carboxylic groups introduced at the end and surface of the carbon nanotubes and different amount of a binder from each other mixed therein.

5. The touch panel of claim 4, wherein an amount of the binder included in the adhesive layer is 20˜

99.9 parts by weight based on 100 parts by weight of a mixture of the carbon nanotubes and binder, an amount of the binder included in the primary conductive layer is 0.1˜

50 parts by weight based on 100 parts by weight of the mixture of the carbon nanotubes and binder, and an amount of the binder included in the protective layer is 20˜

99.9 parts by weight based on 100 parts by weight of the mixture of the carbon nanotubes and binder, and wherein the binder is selected from the group consisting of photo-curable resins, silane compounds, titanium compounds, copolymers, self-assembled resins, and combinations thereof.

6. The touch panel of claim 5, wherein the lower transparent electrode has a surface resistance of 1×

10³ Ω

/sq or less and a transmissivity of 70% or more in a wavelength of 540˜

560 nm.