Method of making flexible electronic circuitry

• US 6,493,933 B1
• Filed: 10/18/2000
• Issued: 12/17/2002
• Est. Priority Date: 10/18/1999
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Post, E. Rehmi, Gershenfeld, Neil
• Primary Examiner(s): Arbes, Carl J.
• Application Number:
  US09/691,739
• Time in Patent Office: 790 Days
• Field of Search: 298/46, 298/52, 298/25, 298/32
• US Class Current: 29/846
• CPC Class Codes: H01L 2224/05554 being square
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 23/4985 Flexible insulating substrates H01L23/49572 and H01L23/49855 take precedence
• CPC Class Codes: H01L 23/49861 Lead-frames fixed on or encapsulated in insulating substrates H01L23/4985, H01L23/49805 take precedence
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01L 2924/30111 matching
• CPC Class Codes: H05K 1/0283 Stretchable printed circuits
• CPC Class Codes: H05K 1/038 Textiles used as reinforcing materials for organic insulating substrates H05K1/0366
• CPC Class Codes: H05K 3/103 by bonding or embedding conductive wires or strips
• CPC Class Codes: H05K 3/326 the printed circuit having integral resilient or deformable parts, e.g. tabs or parts of flexible circuits H05K3/365 takes precedence
• CPC Class Codes: H05K 7/06 on insulating boards , e.g. wiring harnesses for printed circuits H05K1/18, H05K3/30
• CPC Class Codes: Y10T 29/49117 : Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/4913 : Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49155 : Manufacturing circuit on or in base

Abstract

Stitchable electrical components have flexible, conductive leads and are encased, at least partially, in sealed packages. Conductive threads, yarns, or fiber bundles are patterned onto a flexible substrate (e.g., a textile panel). To form a circuit, the component leads are conductively stitched, spot welded, or otherwise joined to a textile panel so as to form connections between at least some of the stitched leads so as to form an electrical circuit. Alternatively, leads stitched into or otherwise joined to a textile pattern may be welded or otherwise permanently joined to flexible or non-flexible component leads to form a circuit. Multiple panels of circuitry so formed may then be physically and electrically joined at various locations by a combination of stitching, welding, and/or other joining means, preferably with interposed insulating layers, to form a multilayer flexible circuit.

Claims

1. A method of creating an electric circuit on a textile, the method comprising the steps of:

a. providing at least one electrical component comprising;

i. an electronic element comprising a plurality of terminals;

ii. connected to each terminal, a flexible conductive fiber lead for establishing electrical connection to the terminal, the leads having lengths; and

iii. a package surrounding at least a portion of the element and a portion of the lengths of the leads;

b. conductively joining the leads to the textile in a pattern affording insulation space between the leads; and

c. joining conductive traces between at least some of the stitched leads so as to form an electrical circuit.

2. The method of claim 1 wherein at least some of the components comprise round packages, the leads extending radially from the package and being stitched in a radial pattern on the textile.

3. The method of claim 1 wherein at least some of the components comprise polygonal packages having a plurality of straight sides from which leads extend, the leads originating with each side of the package being stitched in parallel on the textile so as to extend transversely from said side.

4. The method of claim 1 wherein the package has a perimeter, the leads being spaced around the perimeter at least 0.05 inch from each other.

5. The method of claim 1 wherein the leads comprise bundles of corrosion-resistant metal fibers each no greater than 10 μ

m in diameter, the leads having insufficient stiffness to retain bends and resisting fatigue under repeated flexure.

6. The method of claim 5 wherein the fibers are steel.

7. The method of claim 1 wherein the traces are stitched with thread comprising conductive fibers and nonconductive fibers, the thread having insufficient stiffness to retain bends and resisting fatigue under repeated flexure.

8. The method of claim 1 wherein the leads comprise, and the traces are stitched with, thread spun from short conductive fibers, the thread having insufficient stiffness to retain bends and resisting fatigue under repeated flexure.

9. The method of claim 1 wherein at least some of the components are assembled according to steps comprising:

a. providing an integrated circuit having a plurality of bond-out pads;

b. disposing the integrated circuit on a leadframe comprising a plurality of stubs;

c. connecting each bond-out pad to a leadframe stub;

d. connecting each of the leads to a bond-out pad connected to a leadframe stub; and

e. hermetically encapsulating the leadframe within a polymeric carrier.

10. The method of claim 9 wherein the leads are welded to the bond-out pads.

11. The method of claim 1 wherein steps (a)-(c) are carried out on a first textile panel, and further comprising the steps of:

a. creating a second circuit on a second textile panel, the circuit comprising stitched conductive traces;

b. bringing the panels into alignment;

c. disposing a nonconductive sheet between the panels; and

d. establishing electrical connections between the traces of the first panel and the traces of the second panel at selected points of overlap therebetween by conductively stitching the traces together at said points.

12. The method of claim 1 wherein the traces are stitched with conductive thread comprising an insulating coating thereon, at least some of the traces crossing other traces without electrical communication therebetween.

13. The method of claim 1 wherein at least some of the electrical components are processors, the traces linking the processors together as a computer network.

14. The method of claim 1 further comprising the step of powering the electrical elements using current generated by triboelectric charging.

15. The method of claim 1 further comprising the step of powering the electrical elements by means of a battery removably connected to the circuit.

16. The method of claim 1 further comprising the step of powering the electrical elements by means of a sealed battery connected to the circuit.

17. The method of claim 1 further comprising the step of powering the electrical elements by means of current transmitted from a power source through a wearer'"'"'s body to the circuit.

18. The method of claim 1 wherein the traces are stitched and the leads are stitched to the traces.

19. The method of claim 1 wherein the traces are stitched and the leads are welded to the traces.