Flexible sensors and applications

• US 9,753,568 B2
• Filed: 03/27/2015
• Issued: 09/05/2017
• Est. Priority Date: 05/15/2014
• Status: Active Grant

• Current Assignee: BeBop Sensors, Inc.
• Original Assignee: BeBop Sensors, Inc.
• Inventors: McMillen, Keith A.
• Primary Examiner(s): Thompson, Timothy
• Assistant Examiner(s): Patel, Amol
• Application Number:
  US14/671,821
• Publication Number:
  US 20150331533A1
• Time in Patent Office: 893 Days
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/227 Sensors with electrical connectors
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: G01L 1/146 for measuring force distributions, e.g. using force arrays G01L1/148 takes precedence
• CPC Class Codes: G01L 1/18 using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
• CPC Class Codes: G01L 1/205 using distributed sensing elements
• CPC Class Codes: G01L 1/26 Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload
• CPC Class Codes: G01L 15/00 Devices or apparatus for measuring two or more fluid pressure values simultaneously
• CPC Class Codes: G01L 17/005 using a sensor contacting the exterior surface, e.g. for measuring deformation
• CPC Class Codes: G01L 9/0052 of piezoresistive elements circuits therefor G01L9/06
• CPC Class Codes: G06F 1/16 Constructional details or arrangements
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: H03K 17/964 Piezoelectric touch switches
• CPC Class Codes: H03K 17/9643 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2017/9602 characterised by the type or shape of the sensing electrodes
• CPC Class Codes: H03K 2217/96019 using conductive paint
• CPC Class Codes: Y10T 29/49156 with selective destruction of conductive paths

Abstract

Sensors incorporating piezoresistive materials are described. One class of includes conductive traces formed directly on or otherwise integrated with the piezoresistive material.

Claims

1. An assembly, comprising:

a printed circuit board assembly (PCBA) including a plurality of pads;

piezoresistive fabric having a plurality of conductors printed thereon, the plurality of conductors being aligned with the plurality of pads;

conductive adhesive providing electrical connections between the pads of the PCBA and the conductors on the piezoresistive fabric; and

a plurality of mechanical members extending through apertures in the PCBA and the piezoresistive fabric, the mechanical members being in contact with the piezoresistive fabric and being deformed to secure the PCBA to the piezoresistive fabric.

2. The assembly of claim 1, wherein the mechanical members comprise one of plastic posts, plastic rivets, metal rivets, or sonic welds.

3. The assembly of claim 1, further comprising a substrate disposed adjacent a side of the piezoresistive fabric opposite the PCBA, the mechanical members extending from the substrate toward the PCBA.

4. The assembly of claim 1, wherein the PCBA includes second pads disposed on a side of the PCBA facing away from the piezoresistive fabric, the assembly further comprising a flexible substrate including a plurality of conductors, the conductors of the flexible substrate being aligned with the second pads of the PCBA, a second conductive adhesive providing electrical connections between the second pads of the PCBA and the conductors of the flexible substrate, the mechanical members also securing the flexible substrate to the piezoresistive fabric.

5. A method for connecting a printed circuit board assembly (PCBA) including a plurality of pads to a piezoresistive fabric having a plurality of conductors printed thereon, comprising:

depositing a conductive adhesive on one or both of the pads of the PCBA and the conductors of the piezoresistive fabric;

aligning the pads of the PCBA with the conductors of the piezoresistive fabric, thereby making electrical connections between the pads of the PCBA and the conductors of the piezoresistive fabric via the conductive adhesive;

inserting mechanical members through apertures in the PCBA and the piezoresistive fabric, the mechanical members being in contact with the piezoresistive fabric; and

deforming the mechanical members to secure the PCBA to the piezoresistive fabric.

6. The method of claim 5, wherein the mechanical members are plastic posts, and wherein deforming the mechanical members comprises heat staking the plastic posts.

7. The method of claim 5, wherein the mechanical members extend from an additional substrate, and wherein inserting the mechanical members comprises placing the additional substrate adjacent a side of the flexible substrate opposite the PCBA.

8. The method of claim 5, wherein the PCBA includes second pads disposed on a side of the PCBA facing away from the piezoresistive fabric, the method further comprising:

depositing a second conductive adhesive on one or both of the second pads of the PCBA and conductors of a flexible substrate;

aligning the conductors of the flexible substrate with the second pads of the PCBA, thereby making electrical connections between the second pads of the PCBA and the conductors of the flexible substrate via the second conductive adhesive; and

inserting the mechanical members through apertures in the flexible substrate;

wherein deforming the mechanical members also secures the flexible substrate to the piezoresistive fabric.

9. An assembly, comprising:

a printed circuit board assembly (PCBA) including a plurality of pads;

a piezoresistive fabric having a plurality of conductors printed thereon, the plurality of conductors being aligned with the plurality of pads; and

a plurality of mechanical members extending through apertures in the PCBA between at least some of the pads and corresponding apertures in the piezoresistive fabric between at least some of the conductors, the mechanical members being deformed to secure the PCBA to the piezoresistive fabric;

wherein electrical connections between the pads of the PCBA and the conductors of the piezoresistive fabric are maintained by mechanical force resulting from securing of the PCBA to the piezoresistive fabric.

10. An assembly, comprising:

a circuit board including a plurality of pads arranged at multiple edges of the circuit board;

a fabric substrate including a plurality of conductors, ends of at least some of the conductors being arranged at multiple edges of the fabric substrate corresponding to the edges of the circuit board;

conductive adhesive providing electrical connections between the pads of the circuit board and corresponding ones of the ends of the conductors of the fabric substrate; and

a plurality of mechanical members extending through the circuit board and the fabric substrate, the mechanical members being deformed to secure the edges of the circuit board to the corresponding edges of the fabric substrate.

11. The assembly of claim 10, wherein the fabric substrate comprises a piezoresistive fabric.

12. The assembly of claim 10, wherein the conductors of the fabric substrate comprise conductive traces formed on a surface of the fabric substrate.

13. The assembly of claim 10, wherein the conductors of the fabric substrate comprise conductive threads integrated with the fabric substrate.

14. The assembly of claim 10, wherein the mechanical members comprise one or more of plastic posts, plastic rivets, metal rivets, or sonic welds.

15. The assembly of claim 10, wherein the conductors of the fabric substrate comprise conductive traces printed on a surface of the fabric substrate, and wherein the conductive adhesive is printed on the ends of the conductors.

16. The assembly of claim 10, further comprising an additional substrate disposed adjacent a side of the fabric substrate opposite the circuit board, the mechanical members extending from the additional substrate toward the fabric substrate and the circuit board.

17. The assembly of claim 10, wherein the edges of the fabric substrate at which the ends of the conductors are arranged define at least part of an aperture in the fabric substrate with which the circuit board is aligned.

18. The assembly of claim 10, wherein the circuit board is secured to a first surface of the fabric substrate, the assembly further comprising:

a second circuit board including a second plurality of pads arranged at one or more edges of the second circuit board; and

second conductive adhesive providing electrical connections between the pads of the second circuit board and corresponding ones of the ends of the conductors of the fabric substrate;

wherein the plurality of mechanical members also extending through the second circuit board and secure the second circuit board to a second surface of the fabric substrate opposite the first surface.

19. A method for connecting a circuit board to a fabric substrate, the circuit board including a plurality of pads arranged at multiple edges of the circuit board, the fabric substrate having a plurality of conductors integrated with the fabric substrate, ends of at least some of the conductors being arranged at multiple edges of the fabric substrate, the method comprising:

depositing a conductive adhesive on one or both of the pads of the circuit board and the conductors of the fabric substrate;

aligning the pads of the circuit board with corresponding conductors of the fabric substrate, thereby making electrical connections between the pads at the edges of the circuit board and the conductors at corresponding edges of the fabric substrate via the conductive adhesive;

inserting mechanical members through the circuit board and the fabric substrate; and

deforming the mechanical members to secure the edges of the circuit board to the corresponding edges of the fabric substrate.

20. The method of claim 19, wherein the conductors of the fabric substrate are conductive traces formed on a surface of the fabric substrate, and wherein depositing the conductive adhesive comprises printing the conductive adhesive on the conductive traces.

21. The method of claim 19, wherein the mechanical members are plastic posts, and wherein deforming the mechanical members comprises heat staking the plastic posts.

22. The method of claim 19, wherein the mechanical members extend from an additional substrate, and wherein inserting the mechanical members comprises placing the additional substrate adjacent a side of the fabric substrate opposite the circuit board.

23. The method of claim 19, wherein the circuit board is secured to a first surface of the fabric substrate, the method further comprising:

depositing a second conductive adhesive on one or both of second pads of a second circuit board and the conductors of the fabric substrate;

aligning the conductors of the fabric substrate with the second pads of the second circuit board, thereby making electrical connections between the second pads of the circuit board and the conductors of the fabric substrate via the second conductive adhesive; and

inserting the mechanical members through the second circuit board;

wherein deforming the mechanical members also secures the second circuit board to a second surface of the fabric substrate opposite the first surface.

24. An assembly, comprising:

a circuit board including a plurality of pads arranged at multiple edges of the circuit board;

a fabric substrate including a plurality of conductors, at least some of the conductors being arranged at multiple edges of the fabric substrate corresponding to the edges of the circuit board; and

a plurality of mechanical members extending through apertures in the circuit board between at least some of the pads and corresponding apertures in the fabric substrate between at least some of the conductors, the mechanical members being deformed to secure the edges of the circuit board to the corresponding edges of the fabric substrate;

wherein electrical connections between the pads of the circuit board and the conductors of the fabric substrate are maintained by mechanical force resulting from securing of the circuit board to the fabric substrate.