Electronic Imager Using an Impedance Sensor Grid Array and Method of Making

• US 20110176037A1
• Filed: 01/15/2010
• Published: 07/21/2011
• Est. Priority Date: 01/15/2010
• Status: Active Grant

• Current Assignee: IDEX Biometrics ASA
• Original Assignee: Picofield Technologies, Inc.
• Inventors: Benkley, Fred G. III
• Granted Patent: US 8,421,890 B2
• Time in Patent Office: Days
• US Class Current: 348/294
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing

Abstract

An novel impedance sensor is provided having a plurality of substantially parallel drive lines configured to transmit a signal into a surface of a proximally located object, and also a plurality of substantially parallel pickup lines oriented substantially perpendicular to the drive lines and separated from the pickup lines by a dielectric to form intrinsic electrode pairs that are impedance sensitive at each of the drive and pickup crossover locations.

Claims

1. An impedance sensor, comprising:

a plurality of substantially parallel drive lines configured to transmit a signal to a proximally located object; and

a plurality of substantially parallel pickup lines oriented substantially perpendicular to the drive lines and separated from the pickup lines by a dielectric to form intrinsic electrode pairs that are impedance sensitive at each drive and pickup crossover location.

2. An impedance sensor according to claim 1, wherein the dielectric is a flexible substrate having both the drive and pickup lines located thereon.

3. An impedance sensor according to claim 1, wherein the dielectric is a flexible substrate having both the drive and pickup lines formed together on a surface wherein said surface is folded to form a grid of said crossover locations.

4. An impedance sensor according to claim 1, wherein the drive lines and pickup lines are coated with a dielectric material and the flexible substrate is folded with the dielectric coating interior to the fold in such way that the dielectric coating forms an insulating layer separating the drive and pickup lines.

5. An impedance sensor according to claim 1, wherein the drive lines and pickup lines are configured on a single flexible dielectric substrate that is folded back to back with the substrate interior to the fold in such a way that the substrate becomes the insulating layer separating the drive and pickup lines

6. An impedance sensor according to claim 1, wherein the drive lines and pickup lines are configured on a single flexible substrate that is folded with the drive and pickup lines interior to the fold and electrically separated with a dielectric spacer to form a multi-layer device.

7. An impedance sensor according to claim 1, wherein the drive lines and pickup lines are configured on separate layers of a substrate.

8. An impedance sensor according to claim 1, wherein the drive lines and pickup lines are configured on separate layers, where at least one of the layers is made of one of a flexible substrate, a rigid substrate, glass, ceramic, and rigid board.

9. An impedance sensor according to claim 1, wherein the drive lines and pickup lines are configured on separate sides of a substrate.

10. An impedance sensor according to claim 1, wherein the drive lines and pickup lines are configured on separate sides of one of a flexible, rigid, glass, and ceramic substrate.

11. A sensor according to claim 1 where the drive and the pickup crossover locations are spaced at a pitch sufficient to resolve the topological features of a proximally located object

12. A sensor according to claim 1 wherein the drive and the pickup crossover locations are spaced at a pitch to form a matrix of focused impedance locations which can differentiate localized variations in dielectric composition of a proximally located object.

13. An impedance sensor according to claim 1 wherein each drive and pickup line crossover location defines a pixel location, where electric fields extend from the crossing drive line to the crossing pickup line to sense the magnitude and/or phase of the radiated electric field at said pixel location.

14. An impedance sensor according to claim 13, wherein a portion of an electric field radiating from the drive line crossing the pixel location is partially absorbed by an object proximate to said pixel location.

15. An impedance sensor according to claim 1, wherein said drive and pickup crossover locations form individual pixels configured to capture image information at the focused sensing locations created at each crossover location.

16. An impedance sensor according to claim 1 wherein the drive lines and pickup lines are configured on a single flexible substrate that is folded over about itself to form a two-layer device, the sensor further comprising:

scanning logic configured to acquire the signal at each formed crossover location.

17. An impedance sensor according to claim 1 wherein the intrinsic electrode pairs formed by the crossover locations are used to sense a local impedance about each crossover location.

18. An impedance sensor according to claim 17, wherein the crossover locations of each drive and pickup line form individual pixels configured to capture a single pixel of image information at the focused sensing location created at the crossover location.

19. An impedance sensor according to claim 17, wherein the crossover locations of each drive and pickup line form individual pixels configured to capture a plurality of pixels of image information.

20. An impedance sensor according to claim 17, further comprising a signal generator configured to generate an AC signal communicated to a drive line, and a signal processor configured to process a resultant signal from a pickup line, wherein said drive and pickup crossover locations form individual pixels configured to capture a plurality of pixels of image information.

21. An impedance sensor according to claim 20, wherein the signal generator is configured to generate multiple excitation frequencies, in any form of simultaneous multitone, sequences of individual tones, or as a chirp.

22. An impedance sensor according to claim 20 wherein the signal generator is configured to transmit a signal to at least one drive line at a time.

23. An impedance sensor according to claim 20, wherein the signal generator is configured to transmit a signal to at least one drive line at a time, and wherein the remaining drive lines are grounded while the signal is being transmitted.

24. An impedance sensor according to claim 20, wherein the signal generator is configured to transmit a signal to a plurality of drive lines substantially simultaneously.

25. An impedance sensor according to claim 20, wherein the signal generator is configured to transmit a signal to at least one drive line at a time, and where the signal processor is configured to receive a resultant signal from a plurality of pickup lines when a drive line is active.

26. An impedance sensor according to claim 28, wherein the signal generator is configured to receive signals from a plurality of pickup lines from a scanning process.

27. An impedance sensor according to claim 1, further comprising a signal generator configured to transmit a signal to at least one drive line at a time, and where the signal processor is configured to receive a resultant signal from a plurality of pickup lines when at least one drive line is active.

28. An impedance sensor according to claim 1, further comprising a signal generator configured to transmit a signal to at least one drive line at a time, and wherein the remaining drive lines are grounded while the signal is being transmitted, wherein at least one pickup line is configured to receive a resultant signal and wherein the remaining pickup lines are grounded while any pickup lines are receiving a resultant signal.

29. An impedance sensor according to claim 1, wherein the signal generator is configured to transmit a signal to at least one drive line at a time, and wherein the remaining drive lines are grounded while the signal is being transmitted, wherein at least one pickup line is configured to receive a resultant signal and wherein adjacent pickup lines are grounded while any pickup lines are receiving a resultant signal.

30. An impedance sensor according to claim 29, wherein adjacent pickup lines are within a range of 10 pickup lines near a pickup line while it is receiving a resultant signal.

31. An impedance sensor according to claim 1, further comprising a detection system configured to subtract the signal on a pickup plate in contact with the object being sensed from the signal on a pickup plate that is isolated from the object being sensed prior to further processing.