Obscured feature detector with advanced trace properties

• US 8,791,708 B2
• Filed: 03/03/2011
• Issued: 07/29/2014
• Est. Priority Date: 03/04/2010
• Status: Active Grant

• Current Assignee: Franklin Sensors Inc.
• Original Assignee: Franklin Sensors Inc.
• Inventors: Dorrough, David M.
• Primary Examiner(s): NGUYEN, HOAI AN D
• Application Number:
  US13/040,206
• Publication Number:
  US 20110215815A1
• Time in Patent Office: 1,244 Days
• Field of Search: 324/663, 324/658, 324/649, 324/600, 324/66, 324/67, 324/326, 333/54, 333/32, 332/86, 336/66
• US Class Current: 324/663
• CPC Class Codes: G01N 27/22 by investigating capacitance
• CPC Class Codes: G01N 27/221 by investigating the dielectric properties using microwaves G01N22/00; measuring loss factors or dielectric constants per se G01R27/26
• CPC Class Codes: G01R 27/26 Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G01V 3/08 operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices with electromagnetic waves G01V3/12
• CPC Class Codes: G01V 3/15 specially adapted for use during transport, e.g. by a person, vehicle or boat

Abstract

A surface-conforming obscured feature detector includes a plurality of sensor plates, each having a capacitance that varies based on the dielectric constant of the materials that compose the surrounding objects and the proximity of those objects. A sensing circuit is coupled to the sensor plates 32 to measure the capacitances of the sensor plates. A controller is coupled to the sensing circuit to analyze the capacitances measured by the sensing circuit. One or a plurality of indicators are coupled to the controller, and are selectively activated to identify the location of an obscured feature behind a surface.

Claims

1. An obscured feature detector comprising:

a plurality of sensor plates, each having a capacitance that varies based on;

(a) the proximity of the sensor plates to one or more surrounding objects, and (b) the dielectric constant(s) of the surrounding object(s);

a sensing circuit coupled to the sensor plates by a plurality of electrically conductive traces, the sensing circuit being configured to measure the capacitances of the sensor plates; and

wherein the electrically conductive traces have a physical trace length defined by the distance along the traces between the sensor plates and the sensing circuit, and the physical trace lengths of two or more of the electrically conductive traces are substantially the same.

2. The obscured feature detector of claim 1, wherein two or more of the electrically conductive traces have a width which is substantially the same.

3. The obscured feature detector of claim 1, wherein the electrically conductive traces comprise a first segment and a second segment, wherein the first segment has a constant first width, and the second segment has a constant second width.

4. The obscured feature detector of claim 1, wherein each of the sensor plates has a length defined by the distance from a first surface to an opposite second surface of a plate;

further wherein each sensor plate has substantially the same length.

5. The obscured feature detector of claim 4, wherein each of the sensor plates has a width defined by the distance from a third surface to an opposite fourth surface of a plate;

further wherein each sensor plate has substantially the same width.

6. The obscured feature detector of claim 1, wherein each of the sensor plates has a thickness defined by the distance from a top surface to a bottom surface of a plate;

further wherein each sensor plate has substantially the same thickness.

7. The obscured feature detector of claim 1, wherein a portion of the electrically conductive path comprises a copper trace on a printed circuit board.

8. The obscured feature detector of claim 1, further comprising:

a controller coupled to the sensing circuit, the controller being configured to analyze the capacitance in the area surrounding each sensor plate measured by the sensing circuit; and

one or a plurality of indicators coupled to the controller, each indicator capable of toggling between a deactivated state and an activated state,

wherein the controller is configured to activate one or more of the indicators to identify a location of an obscured feature.

9. A method of using an obscured feature detector having a plurality of sensor plates to determine the location of an obscured feature behind a surface, the method comprising:

placing the obscured feature detector on the surface;

transmitting a value from the plurality of sensor plates along a plurality of electrically conductive traces to a sensor circuit, wherein a physical trace length of at least two of the conductive traces is substantially equal;

measuring capacitance readings sensed in a plurality of regions, each region corresponding to an area surrounding one or more of the sensor plates and represented by the value transmitted from the plurality of sensor plates; and

identifying, based on the capacitance readings, a location of the obscured feature behind the surface.

10. The method of claim 9, further comprising activating one or more indicators to indicate the location of the obscured feature behind the surface.

11. The method of claim 9, wherein the sensor plates each have a length that is substantially the same.

12. The method of claim 9, wherein the sensor plates each have a width that is substantially the same.

13. The method of claim 9, wherein the sensor plates each have a thickness that is substantially the same.

14. The method of claim 9, wherein a portion of the electrically conductive path comprises a copper trace on a printed circuit board.

15. The method of claim 9, wherein a first segment of an electrically conductive trace is located on a first layer of a printed circuit board, and a second segment of an electrically conductive trace is located on a second layer of a printed circuit board.

16. The method of claim 9, wherein two or more of the electrically conductive traces have substantially the same width.

17. The method of claim 9, wherein the electrically conductive traces have a first segment and a second segment, the first segment having a substantially constant first width, and the second segment having a substantially constant second width.