Two-dimensional sensor arrays

• US 9,652,101 B2
• Filed: 07/15/2015
• Issued: 05/16/2017
• 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): Mercedes, Dismery
• Application Number:
  US14/800,538
• Publication Number:
  US 20150331524A1
• Time in Patent Office: 671 Days
• Field of Search: None
• CPC Class Codes: A43B 3/34 with electrical or electronic arrangements
• CPC Class Codes: A61B 2090/064 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/6804 Garments; Clothes
• CPC Class Codes: A61B 5/6807 Footwear
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• 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 5/0019 by using strain gages, piezoelectric, piezo-resistive or other ohmic-resistance based sensors
• CPC Class Codes: G01L 9/0052 of piezoresistive elements circuits therefor G01L9/06
• CPC Class Codes: G01L 9/06 of piezo-resistive devices
• CPC Class Codes: G06F 1/16 Constructional details or arrangements
• CPC Class Codes: G06F 2203/04102 Flexible digitiser, i.e. constructional details for allowing the whole digitising part of a device to be flexed or rolled like a sheet of paper
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• 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 3/04146 using pressure sensitive conductive elements delivering a boolean signal and located between crossing sensing lines, e.g. located between X and Y sensing line layers
• 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: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/045 : using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

Sensors incorporating piezoresistive materials are described. One class of sensors includes piezoresistive material that is held or otherwise supported adjacent conductive traces on a substrate. Another class of sensors includes conductive traces formed directly on the piezoresistive material. Two-dimensional sensor arrays incorporating piezoresistive materials are also described.

Claims

1. A sensor system, comprising:

piezoresistive fabric having a first side and a second side opposite the first side;

a first substrate in contact with the first side of the piezoresistive fabric, the first substrate having a plurality of conductive routing traces and a plurality of conductive trace groups formed thereon, the conductive routing traces, the conductive trace groups and the piezoresistive fabric forming a two-dimensional sensor array in which each of the conductive trace groups is near an intersection of a corresponding pair of the conductive routing traces, and forms a sensor in the sensor array with a corresponding portion of the piezoresistive fabric, each of the conductive trace groups including two or more conductive sensor traces having complementary shapes in contact with the first side of the corresponding portion of the piezoresistive fabric;

a second substrate in proximity to the sensor array, the second substrate having a surface; and

sensor circuitry configured to receive a sensor signal from each of the conductive trace groups, and, using the sensor signals, to generate data representing locations and magnitudes of force relative to the surface of the second substrate resulting from an object in contact with the sensor system.

2. The sensor system of claim 1, wherein the sensor circuitry is further configured to generate successive frames of the data for the sensor array, and to compare the successive frame of the data to improve reliability of the data.

3. The sensor system of claim 1, wherein the conductive routing traces include first conductive routing traces arranged in a first parallel array, and second conductive routing traces arranged in a second parallel array oriented at 90 degrees to the first array, the sensor circuitry being configured to sequentially drive the first conductive routing traces of the first array to energize the sensors of the sensor array, and to sequentially read the second conductive routing traces of the second array to receive the sensor signals.

4. The sensor system of claim 1, wherein the complementary shapes of each conductive trace group comprise interdigitated extensions of the two or more conductive sensor traces of the conductive trace group.

5. The sensor system of claim 1, wherein the complementary shapes of each conductive trace group comprise clover and cruciform shapes.

6. The sensor system of claim 1, wherein electrical resistance between the conductive sensor traces in each of the conductive trace groups varies with force applied to the surface of the second substrate in a vicinity of the conductive trace group, and wherein each of the sensor signals corresponds to one of the conductive trace groups.

7. The sensor system of claim 1, wherein the piezoresistive fabric is a calendared material.

8. The sensor system of claim 1, further comprising a wireless transceiver configured to transmit the data to a remote system.

9. The sensor system of claim 1, wherein one or more characteristics of the conductive trace groups are configured to achieve a particular dynamic range for the sensor system, the one or more characteristics including one or more of (1) shapes of the conductive sensor traces of each conductive trace group, (2) distances between the conductive sensor traces of each conductive trace group, or (3) conductivity of the conductive sensor traces of each conductive trace group.

10. The sensor system of claim 1, further comprising one or more of (1) force focusing elements configured to focus the force relative to the surface of the second substrate toward corresponding sensors of the sensor array, (2) structural elements configured to resist the force relative to the surface of the second substrate, or (3) cutouts in the piezoresistive fabric.

11. The sensor system of claim 1, wherein the sensor circuitry is configured to determine each of the locations and magnitudes of force using contributions from more than one of the sensor signals.

12. The sensor system of claim 1, wherein the sensor circuitry is configured to determine the locations by comparing each of a plurality of values corresponding to the sensor signals to a threshold.

13. The sensor system of claim 12, wherein the sensor circuitry is configured to determine the threshold using an average of the values.

14. The sensor system of claim 1, wherein the conductive trace groups form a plurality of groups of closely-spaced sensors operating in parallel, and wherein the sensor circuitry is configured to generate the data by averaging values corresponding to the sensor signals for each group of sensors.

15. A sensor system, comprising:

piezoresistive fabric having a first side and a second side opposite the first side;

a plurality of conductive traces integrated with the first side of the piezoresistive fabric, the conductive traces and the piezoresistive fabric forming a two-dimensional sensor array having a plurality of sensors, each sensor including two or more of the conductive traces integrated with the first side of the piezoresistive fabric;

a substrate in proximity to the sensor array, the substrate having a surface; and

sensor circuitry configured to drive first ones of the conductive traces, to receive corresponding signals from second ones of the conductive traces, and, using the signals, to generate data representing locations and magnitudes of force relative to the surface of the substrate resulting from an object in contact with the sensor system.

16. The sensor system of claim 15, wherein the sensor circuitry is further configured to generate successive frames of the data for the sensor array, and to compare the successive frame of the data to improve reliability of the data.

17. The sensor system of claim 15, wherein signal routing portions of the first conductive traces are arranged in a first parallel array, and signal routing portions of the second conductive traces are arranged in a second parallel array oriented at 90 degrees to the first parallel array, the sensor circuitry being configured to sequentially drive the first conductive traces of the first array to energize the sensor array, and to sequentially read the second conductive traces of the second array to receive the signals.

18. The sensor system of claim 17, further comprising a conductive trace pattern proximate each intersection of one of the first conductive traces and one of the second conductive traces, each conductive trace pattern corresponding to one of the sensors and including a first conductive element connected to the corresponding first conductive trace and a second conductive element connected to the corresponding second conductive trace.

19. The sensor system of claim 18, wherein the first and second conductive elements of each conductive trace pattern have complementary clover and cruciform shapes.

20. The sensor system of claim 18, wherein the first and second conductive elements of each conductive trace pattern have interdigitated extensions.

21. The sensor system of claim 15, wherein resistance between the two or more conductive traces of each sensor varies with force applied to the surface of the substrate in a vicinity of the sensor, and wherein each of the signals corresponds to one of the sensors.

22. The sensor system of claim 15, wherein the piezoresistive fabric is a calendared material, and wherein the conductive traces comprise conductive ink printed on the piezoresistive fabric.

23. The sensor system of claim 15, wherein the conductive traces are integrated with only on the first side of the piezoresistive fabric.

24. The sensor system of claim 15, wherein the conductive traces are integrated with both the first and second sides of the piezoresistive fabric.

25. The sensor system of claim 24, wherein at least one of the conductive traces integrated with the first side of the piezoresistive fabric is electrically connected to another one of the conductive traces integrated with the second side of the piezoresistive fabric using a metal via, a metal rivet, or a via through which conductive material has been flowed.

26. The sensor system of claim 15, further comprising an insulating material formed over a portion of at least one of the conductive traces, wherein at least a portion of another one of the conductive traces is formed over the insulating material.

27. The sensor system of claim 15, further comprising a wireless transceiver configured to transmit the data to a remote system.

28. The sensor system of claim 15, wherein one or more characteristics of the conductive traces are configured to achieve a particular dynamic range for the sensor system, the one or more characteristics including one or more of (1) shapes of the conductive traces, (2) distances between the conductive traces, or (3) conductivity of the conductive traces.

29. The sensor system of claim 15, further comprising one or more of (1) force focusing elements configured to focus the force relative to the surface of the substrate toward corresponding sensors of the sensor array, (2) structural elements configured to resist the force relative to the surface of the substrate, or (3) cutouts in the piezoresistive fabric.

30. The sensor system of claim 15, wherein the sensor circuitry is configured to determine each of the locations and magnitudes of force using contributions from more than one of the signals.

31. The sensor system of claim 15, wherein the sensor circuitry is configured to determine the locations by comparing each of a plurality of values corresponding to the signals to a threshold.

32. The sensor system of claim 31, wherein the sensor circuitry is configured to determine the threshold using an average of the values.

33. The sensor system of claim 15, wherein the conductive traces form a plurality of groups of closely-spaced sensors operating in parallel, and wherein the sensor circuitry is configured to generate the data by averaging values corresponding to the signals for each group of sensors.