Transparent conductors including metal traces and methods of making same

• US 10,564,780 B2
• Filed: 08/17/2016
• Issued: 02/18/2020
• Est. Priority Date: 08/21/2015
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Hao, Encai, Stay, Matthew S., Everaerts, Albert I., Ali, Mahfuza B., Wang, Yizhong, Lewandowski, Kevin M., Radloff, Corey J.
• Primary Examiner(s): Rosario, Nelson M
• Application Number:
  US15/747,958
• Publication Number:
  US 20180217697A1
• Time in Patent Office: 1,280 Days
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: H05K 1/0274 Optical details, e.g. printed circuits comprising integral optical means H05K1/0269 takes precedence; coupling light guides with opto-electronic components G02B6/42
• CPC Class Codes: H05K 1/09 Use of materials for the conductive, e.g. metallic pattern
• CPC Class Codes: H05K 1/097 Inks comprising nanoparticles and specially adapted for being sintered at low temperature H05K1/095 takes precedence
• CPC Class Codes: H05K 2201/0108 Transparent
• CPC Class Codes: H05K 2201/026 Nanotubes or nanowires
• CPC Class Codes: H05K 2201/0338 Layered conductor, e.g. layered metal substrate, layered finish layer or layered thin film adhesion layer
• CPC Class Codes: H05K 2201/09245 Crossing layout
• CPC Class Codes: H05K 2201/10151 Sensor
• CPC Class Codes: H05K 2203/0143 Using a roller; Specific shape thereof; Providing locally adhesive portions thereon
• CPC Class Codes: H05K 2203/0315 Oxidising metal
• CPC Class Codes: H05K 2203/0759 Forming a polymer layer by liquid coating, e.g. a non-metallic protective coating or an organic bonding layer
• CPC Class Codes: H05K 2203/0783 Using solvent, e.g. for cleaning; Regulating solvent content of pastes or coatings for adjusting the viscosity
• CPC Class Codes: H05K 2203/125 Inorganic compounds, e.g. silver salt
• CPC Class Codes: H05K 3/105 by conversion of non-conductive material on or in the support into conductive material, e.g. by using an energy beam
• CPC Class Codes: H05K 3/285 Permanent coating compositions

Abstract

A transparent conductor is provided, including a visible light transparent substrate and metal traces disposed on the substrate, and a layer of a second metal deposited on at least a portion of the metal traces. The transparent conductor further includes a layer of a second metal, which conforms to the surface structure of the metal traces on which it is deposited. Optionally, the transparent conductor also includes a coating layer disposed on a portion of the metal traces and the substrate surface. The coating layer includes a polymer prepared from a polymerizable composition containing at least one ionic liquid monomer. A method of forming a transparent conductor is also provided, including obtaining a visible light transparent substrate having metal traces disposed on the substrate and applying a coating composition on a portion of the metal traces and substrate. The coating composition contains at least one noble metal salt and at least one polymerizable ionic liquid monomer.

Claims

1. A transparent conductor comprising:

a visible light transparent substrate;

a plurality of metal traces disposed on a major surface of the substrate, the metal traces comprising a first metal;

a layer of a second metal deposited on a portion of the plurality of metal traces; and

a coating layer disposed on the layer of the second metal and at least a portion of the visible light transparent substrate, the coating layer comprising a polymer prepared from a polymerizable composition comprising at least one ionic liquid monomer, the at least one ionic liquid monomer comprising at least one onium salt having an anion, the anion being a fluoroorganic anion, wherein the polymerizable composition comprises a noble metal salt of the second metal in an amount between 1 parts per million (ppm) and 90 ppm of the polymer.

2. The transparent conductor of claim 1, wherein the layer of the second metal is a reaction product of the first metal and the noble metal salt of the second metal by applying the polymerizable composition on a portion of the plurality of metal traces and at least a portion of the visible light transparent substrate.

3. The transparent conductor of claim 1, wherein the coating layer further comprises a salt of the first metal.

4. The transparent conductor of claim 1, wherein the noble metal salt of the second metal comprises HAuCl₄, PdCl₂, or H₂PtCl₆.

5. The transparent conductor of claim 1, wherein the coating layer is disposed on the portion of the plurality of metal traces in a pattern.

6. The transparent conductor of claim 1, wherein the at least one ionic liquid monomer comprises a polymerizable anion and a cation of the formula:

7. The transparent conductor of claim 6, wherein the polymerizable anion comprises an ethylenically unsaturated polymerizable group and an acidic group selected from a carboxylic acid group (—

COOH), a sulfonic acid group (—

SO₃H), a sulfate group (—

SO₄H), a phosphonic acid group (—

PO₃H₂), a phosphate group (—

OPO₃H), or a salt thereof.

8. The transparent conductor of claim 1, wherein the at least one ionic liquid monomer comprises trimethylacryloxyethyl ammonium bis(trifluoromethyl)sulfonamide.

9. The transparent conductor of claim 1 having an optical haze that is less than 1.6%.

10. The transparent conductor of claim 1 having a surface resistivity of less than or equal to 100 ohms per square.

11. The transparent conductor of claim 1, wherein the noble metal salt is capable of oxidizing the first metal.

12. A method of forming a transparent conductor comprising:

obtaining a visible light transparent substrate comprising a plurality of metal traces disposed on a major surface of the substrate; and

applying a coating composition on a portion of the plurality of metal traces and at least a portion of the visible light transparent substrate, the coating composition comprising at least one noble metal salt and at least one polymerizable ionic liquid monomer,

wherein the applying the coating composition comprises applying the coating composition on a portion of the plurality of metal traces in a pattern, and

wherein the at least one polymerizable ionic liquid monomer comprises at least one of;

(i) trimethylacryloxyethyl ammonium bis(trifluoromethyl)sulfonamide; and

(ii) a polymerizable anion and a cation of the formula;

13. The method of claim 12, wherein the coating composition comprises less than 1% of solvent.

14. The method of claim 12, wherein the plurality of metal traces comprise a metal mesh.

15. A transparent conductor comprising:

a visible light transparent substrate;

a plurality of metal traces disposed on a major surface of the substrate, the metal traces comprising a first metal;

a layer of a second metal deposited on a portion of the plurality of metal traces; and

a coating layer disposed on the layer of the second metal and at least a portion of the visible light transparent substrate, the coating layer comprising a polymer prepared from a polymerizable composition comprising at least one ionic liquid monomer, the at least one ionic liquid monomer comprising at least one of;

(i) trimethylacryloxyethyl ammonium bis(trifluoromethyl)sulfonamide; and

(ii) a polymerizable anion and a cation of the formula;

16. The transparent conductor of claim 15, wherein the at least one ionic liquid monomer comprises trimethylacryloxyethyl ammonium bis(trifluoromethyl)sulfonamide.

17. The transparent conductor of claim 15, wherein the at least one ionic liquid monomer comprises the polymerizable anion and the cation.