Flexible sensors and applications

• US 10,282,011 B2
• Filed: 08/30/2016
• Issued: 05/07/2019
• 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): Mercedes, Dismery
• Application Number:
  US15/251,772
• Publication Number:
  US 20170038881A1
• Time in Patent Office: 980 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. A sensor, comprising:

piezoresistive fabric, the piezoresistive fabric having two opposing surfaces;

a sensor trace pattern including two or more conductive traces of the sensor on a same one of the surfaces of the piezoresistive fabric, wherein resistance between the conductive traces varies with bending or stretching of the piezoresistive fabric;

a plurality of stiffeners attached to or integrated with the piezoresistive fabric in a vicinity of the sensor trace pattern, the plurality of stiffeners including first and second stiffeners positioned relative to each other such that the piezoresistive fabric bends as a hinge along a particular axis in the vicinity of the sensor trace pattern, wherein the plurality of stiffeners are also configured to reduce sensitivity of the sensor to a particular type of force; and

circuitry configured to receive one or more sensor signals from the conductive traces, and to generate one or more force signals representing the bending or stretching of the piezoresistive fabric based on the one or more sensor signals.

2. The sensor of claim 1, wherein the piezoresistive fabric is a stretchable piezoresistive material.

3. The sensor of claim 1, wherein the conductive traces comprise conductive ink printed on the piezoresistive fabric.

4. The sensor of claim 3, wherein the conductive ink comprises an elastomeric ink having conductive particles suspended therein.

5. The sensor of claim 1, wherein the conductive traces comprise conductive paint deposited on the piezoresistive fabric.

6. The sensor of claim 1, wherein the plurality of stiffeners include a plastic film, a fabric, or a cured stiffening agent.

7. The sensor of claim 1, wherein the plurality of stiffeners are configured such that the piezoresistive fabric stretches along a particular axis in a plane of the piezoresistive fabric in a region of the piezoresistive fabric in the vicinity of the sensor trace pattern.

8. The sensor of claim 1, further comprising circuitry configured to receive a first signal from the sensor trace pattern, and to generate a second signal based on the first signal, the second signal being representative of a magnitude and a time-varying characteristic of the bending or stretching of the piezoresistive fabric.

9. A sensor, comprising:

piezoresistive fabric;

a sensor trace pattern including two or more conductive traces of the sensor on the piezoresistive fabric, wherein resistance between the conductive traces varies with bending or stretching of the piezoresistive fabric; and

a plurality of stiffeners attached to or integrated with the piezoresistive fabric in a vicinity of the sensor trace pattern, the plurality of stiffeners including first and second stiffeners, the first stiffener providing a channel in which the second stiffener slides along a particular axis parallel to a plane of the piezoresistive fabric.

10. The sensor of claim 9, wherein the piezoresistive fabric is a stretchable material.

11. The sensor of claim 9, wherein the plurality of stiffeners are further configured to reduce sensitivity of the sensor to a particular type of force.

12. The sensor of claim 9, wherein the plurality of stiffeners include a plastic film, a fabric, or a cured stiffening agent.

13. The sensor of claim 9, wherein the first and second stiffeners are configured such that the piezoresistive fabric stretches along the particular axis in a region of the piezoresistive fabric in the vicinity of the sensor trace pattern.

14. The sensor of claim 13, wherein the first and second stiffeners are further configured to resist distortion or deformation of the region of the piezoresistive fabric out of the plane of the piezoresistive fabric.

15. The sensor of claim 9, further comprising circuitry configured to receive a first signal from the sensor trace pattern, and to generate a second signal based on the first signal, the second signal being representative of a magnitude and a time-varying characteristic of the bending or stretching of the piezoresistive fabric.

16. The sensor of claim 9, wherein the conductive traces comprise conductive ink printed on the piezoresistive fabric.

17. The sensor of claim 16, wherein the conductive ink comprises an elastomeric ink having conductive particles suspended therein.

18. The sensor of claim 9, wherein the conductive traces comprise conductive paint deposited on the piezoresistive fabric.

19. The sensor of claim 9, further comprising circuitry configured to receive one or more sensor signals from the conductive traces, and to generate one or more force signals representing the bending or stretching of the piezoresistive fabric based on the one or more sensor signals.