Method of making stretchable interconnect using magnet wires

• US 9,674,949 B1
• Filed: 04/30/2014
• Issued: 06/06/2017
• Est. Priority Date: 08/27/2013
• Status: Active Grant

• Current Assignee: Flextronics America LLC (Flextronics International Limited)
• Original Assignee: Flextronics America LLC (Flextronics International Limited)
• Inventors: Liu, Weifeng, Feng, Zhen, Mohammed, Anwar
• Primary Examiner(s): Patel, Ishwarbhai B
• Assistant Examiner(s): PAGHADAL, PARESH H
• Application Number:
  US14/266,700
• Time in Patent Office: 1,133 Days
• CPC Class Codes: H05K 1/028 Bending or folding regions of flexible printed circuits H05K1/0283 takes precedence
• CPC Class Codes: H05K 1/0283 Stretchable printed circuits
• CPC Class Codes: H05K 1/09 Use of materials for the conductive, e.g. metallic pattern
• CPC Class Codes: H05K 1/11 Printed elements for providing electric connections to or between printed circuits
• CPC Class Codes: H05K 1/118 specially for flexible printed circuits, e.g. using folded portions
• CPC Class Codes: H05K 1/145 Arrangements wherein electric components are disposed between and simultaneously connected to two planar printed circuit boards, e.g. Cordwood modules
• CPC Class Codes: H05K 2201/0137 Materials
• CPC Class Codes: H05K 2201/0162 Silicon containing polymer, e.g. silicone
• CPC Class Codes: H05K 2201/032 Materials
• CPC Class Codes: H05K 2201/05 Flexible printed circuits [FPCs]
• CPC Class Codes: H05K 2201/10287 Metal wires as connectors or conductors

Abstract

A stretchable wire assembly includes a metal wire coupled between two elastic substrates. The two elastic substrates are selectively coupled together, and the metal wire is attached to one or both elastic substrates at select locations. The form of the metal wire is such that when the elastic substrates are in a relaxed, or non-stretched, state the metal wire forms a tortuous path, such as a waveform, along the coupled elastic substrates. The tortuous path of the metal wire provides slack such that as the elastic substrates are stretched the slack is taken up. Once released, the elastic substrates move from the stretched position to the relaxed, non-stretched position, and slack is reintroduced into the metal wire in the form of the original tortuous path.

Claims

1. A stretchable metal wire assembly comprising:

a. a first elastic substrate having a relaxed, non-stretched state, wherein the first elastic substrate is configured to be stretched along at least a first direction when a stretching force is applied along the first direction, and to return to the non-stretched state when the stretching force is removed, further wherein the first elastic substrate has a first perimeter edge and a second perimeter edge;

b. a metal wire coupled to the first elastic substrate, wherein the metal wire forms a tortuous path relative to at least the first direction when the first elastic substrate is in the non-stretched state thereby enabling bending of the metal wire along at least the first direction upon application and removal of the stretching force;

c. one or more adhesion joints wherein each adhesion joint fixedly attaches a portion of the metal wire to a corresponding portion of the first elastic substrate; and

d. a second elastic substrate coupled to the first elastic substrate such that the metal wire is positioned between the first elastic substrate and the second elastic substrate, further wherein the second elastic substrate has a first perimeter edge and a second perimeter edge, wherein the second elastic substrate is fixedly attached to the first elastic substrate proximate the first perimeter edges of each of the first elastic substrate and the second elastic substrate, and the second elastic substrate is fixedly attached to the first elastic substrate proximate the second perimeter edges of each of the first elastic substrate and the second elastic substrate, wherein the second elastic substrate is further fixedly attached to the first elastic substrate along one or more select cross-sections extending from the first perimeter edges and the second perimeter edges, each cross-section intersecting one of the adhesion joints, thereby forming regions each bounded by the fixedly attached first perimeter edges, the fixedly attached second perimeter edges, and two fixedly attached cross-sections, within each region the first elastic substrate and the second elastic substrate are unattached and the metal wire moves freely relative to the first elastic substrate and the second elastic substrate.

2. The stretchable metal wire assembly of claim 1 wherein the second elastic substrate has a relaxed, non-stretched state, further wherein the second elastic substrate is configured to be stretched along at least the first direction when the stretching force is applied along the first direction, and to return to the non-stretched state when the stretching force is removed.

3. The stretchable metal wire assembly of claim 2 wherein the first elastic substrate and the second elastic substrate are configured to be stretched along a second direction different than the first direction and the metal wire forms the tortuous path relative to the first direction and the second direction.

4. The stretchable metal wire assembly of claim 1 wherein the portion of the metal wire is fixedly attached to the corresponding portion of the first elastic substrate at the adhesion joint using an adhesive material.

5. The stretchable metal wire assembly of claim 1 wherein the portion of the metal wire is fixedly attached to the corresponding portion of the first elastic substrate at the adhesion joint using stitching.

6. The stretchable metal wire assembly of claim 1 wherein the first elastic substrate is fixedly attached to the second elastic substrate proximate the first perimeter edges and the first elastic substrate is fixedly attached to the second elastic substrate proximate the second perimeter edges using an adhesive material.

7. The stretchable metal wire assembly of claim 1 wherein the first elastic substrate is fixedly attached to the second elastic substrate proximate the first perimeter edges and the first elastic substrate is fixedly attached to the second elastic substrate proximate the second perimeter edges using stitching.

8. The stretchable metal wire assembly of claim 1 wherein the first elastic substrate is fixedly attached to the second elastic substrate along the select one or more cross-sections using an adhesive material.

9. The stretchable metal wire assembly of claim 1 wherein the first elastic substrate is fixedly attached to the second elastic substrate along the select one or more cross-sections using stitching.

10. The stretchable metal wire assembly of claim 1 further comprising one or more additional metal wires positioned adjacent to the metal wire and electrically isolated from each other, where each additional metal wire forms the tortuous path.

11. The stretchable metal wire assembly of claim 1 wherein the first elastic substrate and the second elastic substrate comprise one or more of an elastomer, silicone, urethane, latex and elastane.

12. The stretchable metal wire assembly of claim 1 wherein the metal wire comprises one or more of gold, silver, copper, nickel and their alloys.

13. The stretchable metal wire assembly of claim 1 wherein the metal wire comprises a magnet wire.