Capacitive sensing device and method of use

Abstract

The sensing device includes a first electrode, a second electrode surrounding the first electrode, and a sensing module configured to sense a capacitance of the material by applying a voltage between the first electrode and the second electrode while the first electrode and the second electrode are adjacent to the material. A method of operating the sensing device includes applying a voltage between the first electrode and the second electrode while the first electrode and the second electrode are disposed adjacent to the material. The second electrode surrounds the first electrode. The method further includes sensing the capacitance of the material based on a response of the material to the voltage.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is an international application claiming priority to U.S. Provisional Application No. 63 / 142,739, filed January 28, 2021, which claims priority to U.S. Application No. 17 / 511,152, filed October 26, 2021, the contents of both of which are incorporated herein by reference.

[0002]

[0002] The present disclosure relates generally to sensing instruments and methods for using them, and more particularly to sensing instruments and methods for sensing the capacitance of materials. [Background technology]

[0003] Some aircraft include structural components made of aluminum and / or aluminum-containing alloys. Many of these structural components are regularly exposed to ambient environmental conditions, such as wind and rain. Thus, these structural components tend to exhibit corrosion over time, particularly in areas such as riveted joints. Often, the exterior surfaces of these structural components are covered by a paint layer and / or one or more passivation layers, which can make corrosion detection difficult. For example, the paint layer and / or passivation layer can be removed via grinding or other means, and corrosion can be detected by visual inspection. However, this is a time-consuming and labor-intensive process. Therefore, there is a need for devices and methods that facilitate less invasive and more rapid detection of corrosion in structural components. Summary of the Invention

[0004] One aspect of the present disclosure is a sensing device that includes a first electrode, a second electrode surrounding the first electrode, and a sensing module configured to sense the capacitance of a material by applying a voltage between the first electrode and the second electrode while the first electrode and the second electrode are adjacent to the material.

[0005] Another aspect of the present disclosure is a method of operating a sensing device. The method includes applying a voltage between a first electrode and a second electrode while the first electrode and the second electrode are disposed adjacent to a material, where the second electrode surrounds the first electrode. The method further includes sensing a capacitance of the material based on a response of the material to the voltage.

[0006] Yet another aspect of the present disclosure is a method of operating a sensing device. The method includes applying a first voltage between a first electrode and a second electrode while the first electrode and the second electrode are disposed adjacent to a first region of a material, where the second electrode surrounds the first electrode. The method further includes detecting a first capacitance of the material based on a first response of the material to the first voltage, and applying a second voltage between a third electrode and a fourth electrode while the third electrode and the fourth electrode are disposed adjacent to a second region of the material, where the fourth electrode surrounds the third electrode. The method further includes detecting a second capacitance of the material based on a second response of the material to the second voltage, and applying a third voltage between a fifth electrode and a sixth electrode while the fifth electrode and the sixth electrode are disposed adjacent to a third region of the material. In that case, the sixth electrode surrounds the fifth electrode. The method further includes sensing a third capacitance of the material based on a third response of the material to a third voltage.

[0007]

[0007] The terms "about" or "substantially" when referring to a quantity or measurement described in this specification mean that the referenced characteristic, parameter, or value need not be exactly achieved, but that deviations or variations, including, for example, tolerances, measurement errors, measurement accuracy limits, and factors known to those skilled in the art, may occur to an extent that the influence of the characteristic cannot be eliminated.

[0008]

[0008] The use of broader terms such as comprise, include, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. The use of terms such as "optionally," "may," "might," "possibly," etc. with respect to any element of an embodiment means that the element is not required or, alternatively, that the element is required, and both options are within the scope of the embodiment(s).

[0009]

[0009] The use of ordinal numbers such as "first," "second," "third," etc., is not intended to indicate a particular order or importance of those elements, but rather to distinguish one element from another.

[0010]

[0010] The above-described features, functions, and advantages may be realized individually in various embodiments or may be combined into further embodiments, further details of which may be understood by reference to the following description and drawings.

[0011]

[0011] The novel features believed characteristic of the embodiments are set forth in the appended claims. However, exemplary embodiments, as well as preferred modes of use, further objects, and explanations thereof, will best be understood by reading the following detailed description of illustrative embodiments of the present disclosure in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1]

[0012] FIG. 1 is a block diagram of a sensing device according to one embodiment. [Figure 2]

[0013] FIG. 2 is a block diagram of a detection module, according to one embodiment. [Figure 3]

[0014] 1 is a perspective view of an aircraft, according to one embodiment; [Figure 4]

[0015] FIG. 10 is a bottom view of a circuit board and electrodes according to one embodiment. [Figure 5]

[0016] FIG. 2 is a top view of a circuit board according to one embodiment. [Figure 6]

[0017] FIG. 1 is a cross-sectional view of an electrode set, material, and spacer according to one embodiment. [Figure 7]

[0018] FIG. 1 is a cross-sectional view of an electrode set, material, and spacer according to one embodiment. [Figure 8]

[0019] 1 is a cross-sectional view of a material and a circuit board according to one embodiment. [Figure 9]

[0020] 1 is a cross-sectional view of a material and a circuit board according to one embodiment. [Figure 10]

[0021] FIG. 1 illustrates a top view of a region of material, according to one embodiment. [Figure 11]

[0022] FIG. 10 is a bottom view of a row of electrode sets of a sensing device on a circuit board, according to one embodiment. [Figure 12]

[0023] 1 is a cross-sectional view of a row of electrode sets and materials for a sensing device, according to one embodiment. [Figure 13]

[0024] FIG. 10 is a bottom view of a row of electrode sets of a sensing device on a circuit board, according to one embodiment. [Figure 14]

[0025] 1 is a cross-sectional view of a row of electrode sets and materials for a sensing device, according to one embodiment. [Figure 15]

[0026] FIG. 1 illustrates a top view of a circuit board and materials according to one embodiment. [Figure 16]

[0027] FIG. 1 illustrates a top view of a circuit board and materials according to one embodiment. [Figure 17]

[0028] 1 illustrates a display component of a user interface, according to one embodiment. [Figure 18]

[0029] 1 is a cross-sectional view of a circuit board and material according to one embodiment. [Figure 19]

[0030] 1 is a block diagram of a method according to one embodiment. [Figure 20]

[0031] 1 is a block diagram of a method according to one embodiment. [Figure 21]

[0032] 1 is a block diagram of a method according to one embodiment. [Figure 22]

[0033] 1 is a block diagram of a method according to one embodiment. [Figure 23]

[0034] 1 is a block diagram of a method according to one embodiment. [Figure 24]

[0035] 1 is a block diagram of a method according to one embodiment. [Figure 25]

[0036] 1 is a block diagram of a method according to one embodiment. [Figure 26]

[0037] 1 is a block diagram of a method according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013]

[0038] As discussed above, there is a need for instruments and methods that facilitate less invasive and more rapid detection of corrosion in structural components. Often, the exterior surfaces of these structural components are covered with a layer of paint and / or one or more passivation layers. Unlike conventional instruments and methods, the instruments and methods disclosed herein can be used to detect corrosion without removing the paint or passivation layers.

[0014]

[0039] Some embodiments disclosed herein include a sensing device that includes a first electrode, a second electrode surrounding the first electrode, and a sensing module configured to sense the capacitance of a material by applying a voltage between the first electrode and the second electrode while the first electrode and the second electrode are adjacent to the material.

[0015]

[0040] Further embodiments disclosed herein include a method of operating a sensing device, the method including applying a voltage between a first electrode and a second electrode while the first electrode and the second electrode are disposed adjacent to a material, the second electrode surrounding the first electrode, and detecting a capacitance of the material based on a response of the material to the voltage.

[0016]

[0041] Additionally or alternatively, the first electrode is coplanar with the second electrode and / or the first and second electrodes are in the form of concentric rings substantially parallel to the outer surface of the material being tested. Generally, the first and second electrodes do not contact the material (e.g., the skin of an aircraft wing) during operation, but an electric field generated between the first and second electrodes penetrates the material. The sensing module may include a signal generator configured to apply a voltage between the first and second electrodes and a meter configured to detect a voltage and / or current response of the material to the applied voltage. The capacitance of the material adjacent the first and second electrodes may be derived based on the response. Since the instrument is used to test various areas of the material, the corrosion area can be inferred from variations in the capacitance detected by the sensing module.

[0017]

[0042] Additionally or alternatively, one- or two-dimensional arrays of electrode sets are formed. That is, several first electrodes and corresponding second electrodes form a single row of electrode sets and / or multiple column and row electrode sets. These devices, having multiple sets of electrodes (e.g., concentric and coplanar), are used to detect the capacitance of a material at many different locations within the material (e.g., simultaneously). This capacitance data collected across a line or area of ​​material can be used to generate an "image" in which pixel intensity or color is mapped to levels of capacitance.

[0018]

[0043] The above-described instruments and methods can be advantageous when compared to conventional instruments and methods because they allow for less invasive and more rapid detection of corrosion in various materials. For example, corrosion detection can be performed without removing paint or passivation layers from the surface of the material being tested and without the need to reapply paint or passivation layers. The above-described instruments and methods can also be used to detect corrosion or other anomalies in materials not covered by paint or passivation layers.

[0019]

[0044] Disclosed embodiments will now be described more fully with reference to the accompanying drawings, in which not all embodiments of the present disclosure are shown. Indeed, several different embodiments are described, but they should not be construed as being limited to the embodiments described herein. Rather, these embodiments are described so that this disclosure will be comprehensive and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0020]

[0045] 1-18 depict components of the aircraft, sensing equipment, and / or material being tested and their associated functions.

[0021]

[0046] 1 is a block diagram of a sensing device 100. The sensing device 100 includes a first electrode 102, a second electrode 104 surrounding the first electrode 102, and a sensing module 106. As described in more detail below, the sensing module 106 is configured to sense a capacitance 108 of a material 110 by applying a voltage 112 between the first electrode 102 and the second electrode 104 while the first electrode 102 and the second electrode 104 are adjacent to the material 110. The first electrode 102, the second electrode 104, and possibly other electrodes are collectively referred to as an electrode set 119A. The sensing device 100 also includes a circuit board 116 on which the first electrode 102, the second electrode 104, and possibly other electrodes are disposed.

[0022]

[0047] 2 is a block diagram of the detection module 106. The detection module 106 includes one or more processors 222, a non-transitory computer-readable medium 224, a communication interface 226, a user interface 230, instruments 236, and a signal generator 238. The components of the detection module 106 are linked together by a system bus, network, or other connection mechanism 232.

[0023]

[0048] The one or more processors 222 may be any type of processor(s), such as a microprocessor, a digital signal processor, a multi-core processor, etc., coupled to a non-transitory computer-readable medium 224 .

[0024]

[0049] The non-transitory computer-readable medium 224 can be any type of memory, such as volatile memory, such as random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), or non-volatile memory, such as read-only memory (ROM), flash memory, magnetic or optical disk, or compact disc read-only memory (CD-ROM), among other devices used to temporarily or permanently store data or programs.

[0025]

[0050] Additionally, the non-transitory computer-readable medium 224 stores instructions 234 that are executable by the one or more processors 222 to cause the detection module 106 to perform any of the functions or methods described herein.

[0026]

[0051] The communications interface 226 includes hardware for enabling communications within the sensing module 106 and / or between the sensing module 106 and one or more other devices. The hardware includes, for example, a transmitter 252, a receiver 254, and an antenna 256. The communications interface 226 is configured to facilitate communications with one or more other devices according to one or more wired or wireless communications protocols. For example, the communications interface 226 is configured to facilitate wireless data communications for the sensing module 106 according to one or more wireless communications standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 801.11 standard, the ZigBee standard, the Bluetooth standard, or the like. In another example, the communications interface 226 is configured to facilitate wired data communications with one or more other devices.

[0027]

[0052] The user interface 230 includes one or more pieces of hardware used to provide data and control signals to the detection module 106. For example, the user interface 230 may include a mouse or pointing device, a keyboard or keypad, a microphone, a touchpad, or a touchscreen, among other possible types of user input devices. Generally, the user interface 230 allows an operator to interact with a graphical user interface (GUI) provided by the detection module 106. The user interface 230 generally includes a display component configured to display data. As one example, the user interface 230 includes a touchscreen display. As another example, the user interface 230 includes a flat panel display, such as a liquid crystal display (LCD) or a light-emitting diode (LED) display.

[0028]

[0053] The sensing module 106 also includes a meter 236 (e.g., a multimeter). The meter 236 includes a first port 240 and a second port 242. The first port 240 is configured to receive an electrical cable or other electrical connector connecting the first electrode 102 to the first port 240, and the second port 242 is configured to receive an electrical cable or other electrical connector connecting the second electrode 104 to the second port 242. The meter 236 is configured to sense steady-state and transient voltages present between the first port 240 and the second port 242. The meter 236 is also configured to sense steady-state and transient currents flowing from the first port 240 to the second port 242.

[0029]

[0054] The sensing module 106 also includes a signal generator 238. The signal generator 238 includes a third port 244 and a fourth port 246. The third port 244 is configured to receive an electrical cable or other electrical connector connecting the first electrode 102 to the third port 244, and the fourth port 246 is configured to receive an electrical cable or other electrical connector connecting the second electrode 104 to the fourth port 246. The signal generator 238 is configured to generate an AC or DC voltage or current between the third port 244 and the fourth port 246 to induce a steady-state voltage and / or current and / or a transient voltage and / or current response in the material being tested. The material's response is sensed, for example, by the meter 236 and used to determine the capacitance of the material.

[0030]

[0055] 3 is a perspective view of an aircraft 700. The aircraft 700 includes a nose 710, wings 720a, 720b, a fuselage 725, and a tail section 730. The aircraft 700 includes a number of areas arranged for the storage of items during flight. In one embodiment, the fuselage 725 includes a storage area below the passenger cabin for storing baggage and other items or supplies. In another embodiment, the passenger cabin within the fuselage 725 includes overhead bins and under-seat areas for storing additional items.

[0031]

[0056] Additionally or alternatively, sensing device 100 may be used to determine the capacitance of various areas of structural components (e.g., skin panels) that form various components of aircraft 700. Capacitance that changes significantly from a baseline is typically assumed to indicate areas of corrosion (e.g., subsurface areas of corrosion) because changes in capacitance generally indicate changes in material composition.

[0032]

[0057] Although aircraft are used herein as an example, the sensing device 100 may also be used to measure the capacitance of materials and / or detect material anomalies within other structures, such as buildings, bridges, boats, ships, and railroad cars, or other vehicles.

[0033]

[0058] 4 is a bottom view of the circuit board 116 and the electrodes. Electrode set 119A includes a first electrode 102, a second electrode 104, and a third electrode 114. The first electrode 102, the second electrode 104, and the third electrode 114 are conductive (e.g., metallic) and are printed or otherwise formed on a first side 118 (e.g., the bottom side) of the circuit board 116.

[0034]

[0059] The first electrode 102 has a cylindrical shape, although other examples are possible. The second electrode 104 and the third electrode 114 each have a ring shape, although other examples are possible. The second electrode 104 surrounds the first electrode 102, and the third electrode 114 surrounds both the second electrode 104 and the first electrode 102. The first electrode 102, the second electrode 104, and the third electrode 114 each have a thickness measured in a normal direction from the first side surface 118 ranging from 1 μm to 1 mm. The thicknesses of the first electrode 102, the second electrode 104, and the third electrode 114 are generally substantially equal to one another.

[0035]

[0060] Both the first electrode 102 and the second electrode 104 have mirror symmetry and rotational symmetry. Therefore, the first electrode 102, the second electrode 104, and the third electrode 114 also have rotational symmetry and mirror symmetry. The first electrode 102, the second electrode 104, and the third electrode 114 are also coplanar. The rotational symmetry, mirror symmetry, and coplanar electrodes help to eliminate undesirable electric field fringing during use.

[0036]

[0061] The circuit board 116 may be a printed circuit board (PCB) or another type of circuit board. Generally, the circuit board 116 will have an electrically insulating core with a conductive circuit printed on it.

[0037]

[0062] FIG. 5 is a top view of circuit board 116. Circuit board 116 includes a metal shielding layer 120 on a second side 122 of circuit board 116 opposite a first side 118. The metal shielding layer 120 can serve to insulate the circuit board 116 from an external electric field.

[0038]

[0063] FIG. 6 is a cross-sectional view of electrode set 119A, material 110, and spacer 124. In FIG. 6, spacer 124 takes the form of a piece of an electrical insulating material such as a foam or another low-k dielectric material (e.g., 1.0 < k < 3.0). For ease of use, spacer 124 will typically be formed of a lightweight material. Spacer 124 maintains a minimum distance 126 (substantially equal to the thickness of spacer 124) between (i) first electrode 102 or second electrode 104 and (ii) material 110. The minimum distance 126 can range from 0.05 mm to 3 mm, although other examples are possible. The minimum distance 126 is generally selected such that an electric field generated between first electrode 102 and second electrode 104 passes through material 110 without causing a short circuit between first electrode 102 and second electrode 104. Material 110 is, for example, a part of nose 710, wing 720a, wing 720b, fuselage 725, or tail 730 of aircraft 700. Additionally or alternatively, the minimum distance 126 can be implemented to be approximately equal to the diameter d3 of electrode set 119A (see FIG. 16).

[0039]

[0064] FIG. 7 is a cross-sectional view of another embodiment of electrode set 119A, material 110, and spacer 124. In FIG. 7, spacer 124 includes platform 125 and three studs 123. The studs 123 have equal depths corresponding to the vertical direction in FIG. 7. The equal depths define a plane. The depth of stud 123 added to the depth of platform 125 equals minimum distance 126. Stud 123 may be formed of plastic, although other examples are possible. In some implementations, stud 123 is replaced by a wheel having an equal thickness. The three studs 123 define a plane that allows electrode set 119A to maintain a substantially constant distance (e.g., minimum distance 126) from material 110. This helps maintain accuracy and / or consistency of capacitance measurements.

[0040]

[0065] 8 is a cross-sectional view of material 110 and circuit board 116. A signal generator 238 of sensing device 100 applies a voltage 112 (e.g., AC and / or DC) between first electrode 102 and second electrode 104 while the first electrode 102 and second electrode 104 are positioned adjacent to material 110. As shown, second electrode 104 surrounds first electrode 102.

[0041]

[0066] The first electrode 102 and the second electrode 104 being "adjacent" to the material 110 may mean that the first electrode 102 and the second electrode 104 are sufficiently close to the material 110, based on the voltage 112 and the geometry of the first electrode 102 and the second electrode 104, so that a majority of the electric field 113 generated by the voltage 112 penetrates the material 110. For example, "adjacent" may generally mean that the first electrode 102 and the second electrode 104 are sufficiently close to the material 110 (e.g., not touching) so that the capacitance of the material 110 can be accurately sensed. In some embodiments, the term "adjacent" refers to a separation between the material 110 and the first electrode 102 or the second electrode 104 ranging from 0.05 mm to 3 mm, although other examples are possible. A person skilled in the art would be able to determine the appropriate distance between the material 110 and the first electrode 102 and / or the second electrode 104 based on the voltage 112 and the geometry of the first electrode 102 and / or the second electrode 104.

[0042]

[0067] The meter 236 then detects the capacitance 108 of the material 110 based on the response V1 of the material 110 to the voltage 112. The response V1 is generally detected by the meter 236 between the first electrode 102 and the second electrode 104, although other examples are possible. The response V1 may take the form of, for example, a transient or steady voltage or current having a particular amplitude or magnitude and / or a particular decay constant or phase relative to the voltage 112. The amplitude, magnitude, decay constant, and / or phase are used to determine the capacitance 108. Note that the signal generator 238 has a finite series resistance, which typically causes the response V1 to be different from the voltage 112 because some of the voltage generated by the signal generator 238 drops across the series resistance and does not drop completely between the first electrode 102 and the second electrode 104.

[0043]

[0068] 9 is a cross-sectional view of material 110 and a version of circuit board 116 that includes third electrode 114. Signal generator 238 applies first voltage 112 between first electrode 102 and second electrode 104 while simultaneously applying second voltage 135 between first electrode 102 and third electrode 114. Second voltage 135 is applied while third electrode 114 is also positioned adjacent to material 110. As shown, third electrode 114 surrounds second electrode 104. Signal generator 238 applying second voltage 135 generally shapes the electric field 113 generated between first electrode 102 and second electrode 104. For example, changing the magnitude and / or polarity of second voltage 135 typically changes the depth to which the majority of electric field 113 penetrates into material 110. By varying the depth of the electric field 113, capacitance measurements or anomalies can be made within different depth ranges in the material 110.

[0044]

[0069] It should also be noted that first voltage 112 and second voltage 135 can be generated in ways other than those depicted in FIG. 9. For example, first voltage 112 and second voltage 135 can both have their negative terminals at a common ground connection. Other examples are possible. Meter 236 then senses capacitance 108 of material 110 as described above with reference to FIG. 8. However, second voltage 135 generally affects capacitance 108 as sensed by meter 236, for example, by changing the volume of material 110 that capacitance 108 actually represents (e.g., by changing the shape of electric field 113).

[0045]

[0070] 10 is a top view of material 110, illustrating regions 150, 152, 154, 156, 158, 190, 192, 194, 196, and 198 of material 110. As described below with reference to FIGS. 11-14, sensing device 100 is used to determine the respective capacitances corresponding to regions 150, 152, 154, 156, 158, 190, 192, 194, 196, and 198 of material 110.

[0046]

[0071] Figure 11 is a bottom view of a row of electrode sets 119A, 119B, 119C, 119D, and 119E of sensing device 100 on circuit board 116. Although five electrode sets are shown in Figure 11, any number of electrode sets may be included as part of circuit board 116. Additional electrode sets provide an additional element of independent control during testing of the material and may also reduce the amount of time required to inspect a given area and / or volume of material.

[0047]

[0072] The sensing device 100 includes an electrode set 119B on the first side 118 of the circuit board 116. The electrode set 119B includes a third electrode 128 and a fourth electrode 130 that surrounds the third electrode 128.

[0048]

[0073] The sensing device 100 also includes an electrode set 119C on the first side 118 of the circuit board 116. The electrode set 119C includes a fifth electrode 132 and a sixth electrode 134 that surrounds the fifth electrode 132.

[0049]

[0074] Sensing device 100 also includes electrode set 119D and electrode set 119E, both of which generally have all of the characteristics of electrode sets 119A-C (e.g., two or three concentric and / or coplanar electrodes).

[0050]

[0075] As shown, first electrode 102, third electrode 128, and fifth electrode 132 are collinear. The center points of second electrode 104, fourth electrode 130, and sixth electrode 134 are also collinear. Thus, electrode sets 119A, 119B, 119C, 119D, and 119E form a line that can be scanned across material 110 to make capacitance measurements across a two-dimensional area.

[0051]

[0076] The signal generator 238 applies a second voltage 136 between the third electrode 128 and the fourth electrode 130 while the third electrode 128 and the fourth electrode 130 are adjacent to the material 110 (not shown in FIG. 11 ). The signal generator 238 may, for example, apply the second voltage 136 simultaneously with applying the first voltage 112.

[0052]

[0077] The signal generator 238 also applies a third voltage 138 between the fifth electrode 132 and the sixth electrode 134 while the fifth electrode 132 and the sixth electrode 134 are adjacent to the material 110 (not shown in FIG. 11 ). This voltage applied between the electrodes is used to measure the capacitance of the material 110 under each electrode.

[0053]

[0078] FIG. 12 is a cross-sectional view of a row of electrode sets 119A, 119B, 119C, 119D, and 119E of sensing device 100 on circuit board 116. As shown in FIG.

[0054]

[0079] A signal generator 238 applies a first voltage 112 between the first electrode 102 and the second electrode 104 while the first electrode 102 and the second electrode 104 are positioned adjacent to a first region 150 of the material 110. As shown, the second electrode 104 surrounds the first electrode 102. The circuit board 116 is manually or automatically positioned such that the first electrode 102 and the second electrode 104 are positioned adjacent to the first region 150.

[0055]

[0080] The meter 236 senses the first capacitance 108 of the material 110 (eg, the first region 150) based on the first response V1 of the material 110 to the first voltage 112.

[0056]

[0081] A signal generator 238 applies a second voltage 136 between the third electrode 128 and the fourth electrode 130 while the third electrode 128 and the fourth electrode 130 are positioned adjacent to a second region 152 of the material 110. As shown, the fourth electrode 130 surrounds the third electrode 128. When the circuit board 116 is positioned so that the first electrode 102 and the second electrode 104 are adjacent to the first region 150, the circuit board 116 is also positioned so that the third electrode 128 and the fourth electrode 130 are adjacent to the second region 152.

[0057]

[0082] The meter 236 senses a second capacitance 161 of the material 110 (eg, the second region 152) based on a second response V2 of the material 110 to the second voltage 136.

[0058]

[0083] The signal generator 238 applies a third voltage 138 between the fifth electrode 132 and the sixth electrode 134 while the fifth electrode 132 and the sixth electrode 134 are positioned adjacent to a third region 154 of the material 110. As shown, the sixth electrode 134 surrounds the fifth electrode 132. When the circuit board 116 is positioned so that the first electrode 102 and the second electrode 104 are adjacent to the first region 150, the circuit board 116 is also positioned so that the fifth electrode 132 and the sixth electrode 134 are adjacent to the third region 154.

[0059]

[0084] The meter 236 senses a third capacitance 163 of the material 110 (eg, the third region 154) based on a third response V3 of the material 110 to the third voltage 138.

[0060]

[0085] The signal generator 238 applies the first voltage 112, the second voltage 136, and the third voltage 138 simultaneously, although other examples are possible. Generally, the first voltage 112, the second voltage 136, and the third voltage 138 are substantially equal in magnitude, timing, phase, and / or waveform. However, there may be situations in which the first voltage 112, the second voltage 136, and / or the third voltage 138 having different amplitudes, timing, phases, and / or waveforms may be beneficial.

[0061]

[0086] FIG. 13 is a bottom view of a row of electrode sets 119A, 119B, 119C, 119D, and 119E of sensing device 100 on circuit board 116. FIG.

[0062]

[0087] Figure 14 is a cross-sectional view of a row of electrode sets 119A, 119B, 119C, 119D, and 119E of sensing device 100 on circuit board 116. In Figure 14, circuit board 116 has been manually or automatically moved to a different position relative to material 110 than the position depicted in Figure 12.

[0063]

[0088] The signal generator 238 applies a fourth voltage 512 between the first electrode 102 and the second electrode 104 while the first electrode 102 and the second electrode 104 are positioned adjacent to the fourth region 190 of the material 110. The fourth voltage 512 can be, but is not required to be, the same as the first voltage 112.

[0064]

[0089] The meter 236 senses a fourth capacitance 508 of the material 110 (eg, the fourth region 190) based on a fourth response V4 of the material 110 to the fourth voltage 512.

[0065]

[0090] The signal generator 238 applies a fifth voltage 536 between the third electrode 128 and the fourth electrode 130 while the third electrode 128 and the fourth electrode 130 are positioned adjacent to a fifth region 192 of the material 110. When the circuit board 116 is positioned so that the first electrode 102 and the second electrode 104 are adjacent to the fourth region 190, the circuit board 116 is also positioned so that the third electrode 128 and the fourth electrode 130 are adjacent to the fifth region 192.

[0066]

[0091] Meter 236 senses a fifth capacitance 561 of material 110 (eg, fifth region 192) based on a fifth response V5 of material 110 to fifth voltage 536.

[0067]

[0092] The signal generator 238 applies a sixth voltage 538 between the fifth electrode 132 and the sixth electrode 134 while the fifth electrode 132 and the sixth electrode 134 are positioned adjacent to a sixth region 194 of the material 110. When the circuit board 116 is positioned so that the first electrode 102 and the second electrode 104 are adjacent to the fourth region 190, the circuit board 116 is also positioned so that the fifth electrode 132 and the sixth electrode 134 are adjacent to the sixth region 194.

[0068]

[0093] Meter 236 senses a sixth capacitance 563 of material 110 (eg, sixth region 194) based on a sixth response V6 of material 110 to sixth voltage 538.

[0069]

[0094] Although the signal generator 238 applies the fourth voltage 512, the fifth voltage 536, and the sixth voltage 538 simultaneously, this is not required.

[0070]

[0095] The fifth voltage 536 and sixth voltage 538 can be the same as the fourth voltage 512, but this is not required.

[0071]

[0096] 15 is a top view of circuit board 116 and material 110. Circuit board 116 is automatically or manually moved or scanned in direction 159 to systematically probe various regions of material 110 using electrode sets 119A, 119B, 119C, 119D, and 119E. During or after such scanning, sensing module 106 measures baseline capacitance C b represents the average expected capacitance of the material 110 in the absence of substantial anomalies, such as corrosion. In one example, electrode set 119A is positioned at some point over an anomaly 146 (e.g., an area of ​​corrosion) in the material 110. The sensing module 106 determines whether the capacitance 108 of the material 110 (e.g., anomaly 146) exceeds a threshold difference C t beyond the baseline capacitance C b In FIG. 15, the capacitance 108 is determined to be different from C xy In some embodiments, the threshold difference C t is the baseline capacitance C b The threshold difference C can be 1%, 2%, 3%, 5%, 10%, or 15% of the threshold. t is selected to represent a variation in capacitance large enough to provide some degree of certainty that an anomaly has been detected. Those skilled in the art will recognize how to select a threshold difference that accurately represents an anomaly in material 110 (e.g., via a diagnostic test).

[0072]

[0097] The sensing module 106 measures the capacitance 108 (e.g., C xy ) is the threshold difference C t beyond the baseline capacitance C b In response to determining that the measured values ​​differ from the measured values, the user interface 230 provides an indication 144 that an anomaly 146 exists beneath the first electrode 102 and the second electrode 104. This is shown in FIG. 17 and described in more detail below.

[0073]

[0098] After inspecting the anomaly 146, the circuit board 116 is moved in a direction 169 so that the electrode set 119A is over the test area 148 of the material 110. The electrode set 119A senses (e.g., continuously) the capacitance of the material 110 while the first electrode 102 and the second electrode 104 are moved over the material 110, away from the anomaly 146 and adjacent to the test area 148. The sensing module 106 low-pass filters the sensed capacitance as the first electrode 102 and the second electrode 104 are moved in the direction 169. The low-pass filter helps to ignore changes in capacitance that may occur due to slow changes in the distance between the electrode set 119A and the material 110 while the circuit board 116 is moved in the direction 169. This change in distance may be due, for example, to user error or non-idealities in the spacer 124. The low-pass filter allows for focus on more rapid changes in capacitance, which are more likely to represent changes in the composition of the material 110. Gradual changes in capacitance that occur while the circuit board 116 is moving can therefore be ignored, as they are more likely to reflect non-idealities in the sensing device 100 and less likely to reflect changes in the composition of the material 110.

[0074]

[0099] Additionally, the sensing module 106 detects using the electrode set 119C that the capacitance of the material 110 corresponding to the anomaly 147 is greater than or equal to a threshold difference C t beyond the baseline capacitance C b and, in response, provides an indication 149 via user interface 230 that an anomaly 147 exists under electrode set 119C, as shown in FIG. 17 and described in more detail below.

[0075]

[0100] Figure 16 is a top view of another embodiment of circuit board 116 and material 110. As shown, first electrode 102, third electrode 128, and fifth electrode 132 are not collinear in this embodiment. Figure 16 shows a three-dimensional array of electrode sets 119A, 119B, 119C, 119D, 119E, 119F, 119G, 119H, 119I, and 119J. A three-dimensional array can be useful for quickly testing large volumes and / or areas of material 110.

[0076]

[0101] Circuit board 116 is automatically or manually moved or scanned in direction 159 to systematically probe various regions of material 110 using one or more of electrode sets 119A, 119B, 119C, 119D, 119E, 119F, 119G, 119H, 119I, and 119J. During or after such scanning, sensing module 106 measures the baseline capacitance C b represents the average expected capacitance of the material 110 in the absence of substantial anomalies, such as corrosion. In one example, electrode set 119F is positioned at some point over an anomaly 146 (e.g., an area of ​​corrosion) in the material 110. The sensing module 106 determines whether the capacitance 108 of the material 110 (e.g., anomaly 146) exceeds a threshold difference C t beyond the baseline capacitance C b In FIG. 16, the capacitance 108 is determined to be different from C xy In some embodiments, the threshold difference C t is the baseline capacitance C b The threshold difference C can be 1%, 2%, 3%, 5%, 10%, or 15% of the threshold difference C, but other examples are also possible. t is chosen to represent a variation in capacitance large enough to provide some certainty that an anomaly has been detected.

[0077]

[0102] The sensing module 106 measures the capacitance 108 (e.g., C xy ) is the threshold difference C t beyond the baseline capacitance C bIn response to determining that the difference is from the fifth electrode 132, the user interface 230 provides an indication 144 that an anomaly 146 exists beneath the fifth electrode 132 and the sixth electrode 134. This is shown in FIG. 17 and described in more detail below.

[0078]

[0103] Additionally, the sensing module 106 detects using the electrode set 119C that the capacitance of the material 110 corresponding to the anomaly 147 is greater than or equal to a threshold difference C t beyond the baseline capacitance C b and, in response, provides an indication 149 via user interface 230 that an anomaly 147 exists under electrode set 119C, as shown in FIG. 17 and described in more detail below.

[0079]

[0104] As shown in FIG. 16 , electrode sets 119A-E are each separated from electrode sets 119F-J by a distance d1. In another axis, electrode sets (e.g., electrode set 119D and electrode set 119E) are separated by a distance d2. In general, distances d1 and d2 may be selected and implemented based on the size of the anomaly of interest and / or the expected anomaly. For example, if the anomaly of interest has a diameter on a similar scale to diameter d3 of electrode sets 119A-J, d1 and d2 may be implemented to be approximately half of d3. (d1, d2, and d3 are not necessarily drawn to scale in FIG. 16 .) In some embodiments in which third electrode 114 is used to electromagnetically isolate electrode set 119A from the other electrode sets, electrode sets 119A-J may substantially abut one another.

[0080]

[0105] 17 illustrates a display component of user interface 230. As described above, user interface 230 provides an indication 144 that an anomaly 146 exists beneath first electrode 102 and second electrode 104. For example, indication 144 may include darkening, lightening, or changing the color of an area of ​​the display component corresponding to anomaly 146. In a similar manner, user interface 230 also provides an indication 149 that an anomaly 147 exists beneath electrode set 119C or electrode set 119H.

[0081]

[0106] The capacitance corresponding to anomaly 147, when compared to the capacitance corresponding to anomaly 146, is the baseline capacitance C b Therefore, display 149 may indicate this through differences in brightness or color when compared to display 144. For example, lower pixel intensity may correlate to greater variation from the baseline capacitance, or a color scale may be used to indicate the difference in baseline capacitance C b The capacitance values ​​may be mapped to different levels of difference from the measured capacitance. In some examples, the actual capacitance values ​​may be displayed in the respective regions within the user interface 230. Other examples are possible. These concepts may also be applied in three dimensions to achieve a three-dimensional mapping of anomalies within the material 110. Such mapping may be obtained periodically over time to identify degradation trends in the material 110.

[0082]

[0107] 18 is a cross-sectional view of the circuit board 116 and the material 110. The sensing module 106 detects whether the first capacitance 108 of the material 110 is greater than or equal to a threshold difference C t beyond the baseline capacitance C band accordingly identifies a depth 171 of the anomaly 146 under the first electrode 102 and the second electrode 104 (e.g., electrode set 119A) based on the first capacitance 108, the second capacitance 161, and the third capacitance 163. Further, the user interface 230 provides an indication (e.g., a numerical indication) of the depth 171 of the anomaly 146 under the first electrode 102 and the second electrode 104. In some examples, a crosstalk phenomenon exists in which electrode set 119A, electrode set 119B, and electrode set 119C all detect the anomaly 146, and the baseline capacitance C b Each deviation of the capacitance from is inversely proportional to the distance of the electrode set from the anomaly 146. In this manner, triangulation techniques can be applied to the first capacitance 108, the second capacitance 161, and the third capacitance 163 to determine the depth 171 and / or size 173 (e.g., diameter) of the anomaly 146. Accordingly, the user interface 230 provides an indication (e.g., a numerical indication) of the size 173 and / or depth 171.

[0083]

[0108] 19-26 are block diagrams of methods 200, 201, 203, 205, 300, 301, 303, and 305 for operating a sensing device. Methods 200, 201, 203, 205, 300, 301, 303, and 305 provide examples of methods that may be used with sensing device 100 and material 110 shown in FIGS. 1-18. As shown in Figures 19-26, methods 200, 201, 203, 205, 300, 301, 303, and 305 include one or more operations, functions, or acts as illustrated by blocks 202, 204, 206, 208, 210, 212, 214, 302, 304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324, 326, 328, 330, 332, 334, and 336. While the blocks are shown sequentially, these blocks may also be performed in parallel and / or in a different order than described herein. Additionally, various blocks may be combined into fewer blocks, divided into additional blocks, and / or eliminated based on a desired implementation.

[0084]

[0109] FIG. 19 is a block diagram of the method 200.

[0085]

[0110] In block 202, the method 200 includes applying a first voltage 112 between the first electrode 102 and the second electrode 104 while the first electrode 102 and the second electrode 104 are disposed adjacent to the material 110. In this context, the second electrode 104 surrounds the first electrode 102.

[0086]

[0111] At block 204 , the method 200 includes sensing the capacitance 108 of the material 110 based on the response V 1 of the material 110 to the first voltage 112 .

[0087]

[0112] FIG. 20 is a block diagram of the method 201.

[0088]

[0113] In block 206, the method 201 includes applying a second voltage 135 between the first electrode 102 and the third electrode 114 simultaneously with applying the first voltage 112. The second voltage 135 is applied while the third electrode 114 is disposed adjacent to the material 110. The third electrode 114 surrounds the second electrode 104.

[0089]

[0114] FIG. 21 is a block diagram of the method 203.

[0090]

[0115] In block 208, the method 203 determines whether the first capacitance 108 of the material 110 exceeds a threshold difference C t beyond the baseline capacitance C b This includes determining that the value is different from the value of the original value.

[0091]

[0116] In block 210, the method 203 includes, in response to the determination, providing an indication 144 via the user interface 230 that an abnormality 146 exists beneath the first electrode 102 and the second electrode 104.

[0092]

[0117] FIG. 22 is a block diagram of the method 205.

[0093]

[0118] In block 212, the method 205 includes detecting the first capacitance 108 of the material 110 while moving the first electrode 102 and the second electrode 104 over the material 110 adjacent to the test area 148 of the material 110.

[0094]

[0119] At block 214, the method 205 includes low-pass filtering the sensed first capacitance 108 while moving the first electrode 102 and the second electrode 104.

[0095]

[0120] FIG. 23 is a block diagram of the method 300.

[0096]

[0121] At block 302, the method 300 includes applying a first voltage 112 between the first electrode 102 and the second electrode 104 while the first electrode 102 and the second electrode 104 are disposed adjacent to a first region 150 of the material 110. In this context, the second electrode 104 surrounds the first electrode 102.

[0097]

[0122] At block 304 , the method 300 includes sensing the capacitance 108 of the material 110 based on the response V 1 of the material 110 to the first voltage 112 .

[0098]

[0123] At block 306, the method 300 includes applying a second voltage 136 between the third electrode 128 and the fourth electrode 130 while the third electrode 128 and the fourth electrode 130 are disposed adjacent to the second region 152 of the material 110. In this context, the fourth electrode 130 surrounds the third electrode 128.

[0099]

[0124] At block 308, the method 300 includes sensing a second capacitance 161 of the material 110 based on a second response V2 of the material 110 to the second voltage 136.

[0100]

[0125] At block 310, the method 300 includes applying a third voltage 138 between the fifth electrode 132 and the sixth electrode 134 while the fifth electrode 132 and the sixth electrode 134 are disposed adjacent to the third region 154 of the material 110. In this context, the sixth electrode 134 surrounds the fifth electrode 132.

[0101]

[0126] At block 312, the method 300 includes sensing a third capacitance 163 of the material 110 based on a third response V3 of the material 110 to the third voltage 138.

[0102]

[0127] FIG. 24 is a block diagram of the method 301.

[0103]

[0128] At block 314, the method 301 determines whether the first capacitance 108 of the material 110 exceeds a threshold difference C t beyond the baseline capacitance C b This includes determining that the value is different from the value of the original value.

[0104]

[0129] In block 316, the method 301 includes, in response to the determination, determining a depth 171 of the anomaly 146 below the first electrode 102 and the second electrode 104 based on the first capacitance 108, the second capacitance 161, and the third capacitance 163.

[0105]

[0130] At block 318 , the method 301 includes providing, via the user interface 230 , an indication of the depth 171 of the abnormality 146 below the first electrode 102 and the second electrode 104 .

[0106]

[0131] FIG. 25 is a block diagram of the method 303.

[0107]

[0132] In block 320, the method 303 determines whether the first capacitance 108 of the material 110 exceeds a threshold difference C t beyond the baseline capacitance C b This includes determining that the value is different from the value of the original value.

[0108]

[0133] In block 322, the method 303 includes, in response to the determination, identifying a size 173 of the anomaly 146 under the first electrode 102 and the second electrode 104 based on the first capacitance 108, the second capacitance 161, and the third capacitance 163.

[0109]

[0134] At block 324 , the method 303 includes providing, via the user interface 230 , an indication of the size 173 of the abnormality 146 under the first electrode 102 and the second electrode 104 .

[0110]

[0135] FIG. 26 is a block diagram of the method 305.

[0111]

[0136] In block 326, the method 305 includes applying a fourth voltage 512 between the first electrode 102 and the second electrode 104 while the first electrode 102 and the second electrode 104 are positioned adjacent to the fourth region 190 of the material 110.

[0112]

[0137] At block 328, the method 305 includes sensing a fourth capacitance 508 of the material 110 based on a fourth response V4 of the material 110 to a fourth voltage 512.

[0113]

[0138] In block 330, the method 305 includes applying a fifth voltage 536 between the third electrode 128 and the fourth electrode 130 while the third electrode 128 and the fourth electrode 130 are positioned adjacent to the fifth region 192 of the material 110.

[0114]

[0139] At block 332, the method 305 includes sensing a fifth capacitance 561 of the material 110 based on a fifth response V5 of the material 110 to the fifth voltage 536.

[0115]

[0140] In block 334, the method 305 includes applying a sixth voltage 538 between the fifth electrode 132 and the sixth electrode 134 while the fifth electrode 132 and the sixth electrode 134 are positioned adjacent to the sixth region 194 of the material 110.

[0116]

[0141] At block 336 , the method 305 includes sensing a sixth capacitance 563 of the material 110 based on a sixth response V 6 of the material 110 to the sixth voltage 538 .

[0117]

[0142] Additionally, the present disclosure includes embodiments according to the following clauses:

[0118]

[0143] Clause 1 1. A sensing device comprising: a first electrode; a second electrode surrounding the first electrode; and a sensing module configured to sense a capacitance of the material by applying a voltage between the first electrode and the second electrode while the first electrode and the second electrode are adjacent to the material.

[0119]

[0144] Clause 2 2. The sensing device of claim 1, wherein the first electrode is coplanar with the second electrode.

[0120]

[0145] Clause 3 3. The sensing device of clause 1 or 2, wherein the first electrode and the second electrode both have mirror symmetry and rotational symmetry.

[0121]

[0146] Clause 4 4. The sensing device of any one of clauses 1 to 3, further comprising a third electrode surrounding the first electrode and the second electrode.

[0122]

[0147] Clause 5 5. The detection device of any one of clauses 1 to 4, further comprising a circuit board, wherein the first electrode and the second electrode are disposed on a first side of the circuit board, and the circuit board comprises a metal shielding layer on a second side of the circuit board opposite the first side.

[0123]

[0148] Clause 6 6. The sensing device of any one of clauses 1 to 5, further comprising a spacer configured to maintain a minimum distance between (i) the first electrode or the second electrode and (ii) the material.

[0124]

[0149] Clause 7 The detection device of any one of clauses 1 to 6, further comprising a third electrode, a fourth electrode surrounding the third electrode, a fifth electrode, and a sixth electrode surrounding the fifth electrode, wherein the first electrode, the third electrode, and the fifth electrode are collinear, and the detection module is further configured to apply a second voltage between the third electrode and the fourth electrode while the third electrode and the fourth electrode are adjacent to the material, and apply a third voltage between the fifth electrode and the sixth electrode while the fifth electrode and the sixth electrode are adjacent to the material.

[0125]

[0150] Article 8 The sensing device of any one of clauses 1 to 6, further comprising a third electrode, a fourth electrode surrounding the third electrode, a fifth electrode, and a sixth electrode surrounding the fifth electrode, wherein the first electrode, the third electrode, and the fifth electrode are not collinear, and the sensing module is further configured to apply a second voltage between the third electrode and the fourth electrode while the third electrode and the fourth electrode are adjacent to the material, and apply a third voltage between the fifth electrode and the sixth electrode while the fifth electrode and the sixth electrode are adjacent to the material.

[0126]

[0151] Article 9 1. A method of operating a sensing device, the method comprising: applying a voltage between a first electrode and a second electrode while the first electrode and the second electrode are positioned adjacent to a material, the second electrode surrounding the first electrode; and sensing a capacitance of the material based on a response of the material to the voltage.

[0127]

[0152] Article 10 10. The method of clause 9, wherein applying the voltage includes applying the voltage while the first electrode and the second electrode are not in contact with the material.

[0128]

[0153] Article 11 11. The method of claim 9 or 10, wherein the voltage is an alternating current (AC) voltage.

[0129]

[0154] Article 12 12. The method of any one of clauses 9 to 11, wherein the voltage is a first voltage, and the method further comprises applying a second voltage between the first electrode and a third electrode simultaneously with applying the first voltage, the second voltage being applied while the third electrode is positioned adjacent to the material, and the third electrode surrounds the second electrode.

[0130]

[0155] Article 13 13. The method of claim 12, wherein applying the second voltage includes applying the second voltage to shape an electric field generated between the first electrode and the second electrode.

[0131]

[0156] Article 14 14. The method of any one of clauses 9 to 13, further comprising: determining that the capacitance of the material differs from a baseline capacitance by more than a threshold difference; and, in response to the determination, providing an indication via a user interface that an anomaly exists beneath the first electrode and the second electrode.

[0132]

[0157] Article 15 15. The method of any one of clauses 9 to 14, further comprising sensing the capacitance of the material while moving the first electrode and the second electrode over the material adjacent to a second region of the material, and low pass filtering the sensed capacitance while moving the first electrode and the second electrode.

[0133]

[0158] Article 16 1. A method of operating a sensing device, comprising: applying a first voltage between a first electrode and a second electrode while the first electrode and the second electrode are disposed adjacent a first region of a material, the second electrode surrounding the first electrode; detecting a first capacitance of the material based on a first response of the material to the first voltage; applying a second voltage between a third electrode and a fourth electrode while the third electrode and the fourth electrode are disposed adjacent a second region of the material; a fourth electrode surrounding the third electrode; applying a second voltage; and detecting a second capacitance of the material based on a second response of the material to the second voltage; applying a third voltage between a fifth electrode and a sixth electrode while the fifth electrode and a sixth electrode are disposed adjacent a third region of the material, the sixth electrode surrounding the fifth electrode; applying a third voltage; and detecting a third capacitance of the material based on a third response of the material to the third voltage.

[0134]

[0159] Article 17 17. The method of claim 16, further comprising: determining that the first capacitance of the material differs from a baseline capacitance by more than a threshold difference; in response to the determination, identifying a depth of an anomaly beneath the first electrode and the second electrode based on the first capacitance, the second capacitance, and the third capacitance; and providing an indication of the depth of the anomaly beneath the first electrode and the second electrode via a user interface.

[0135]

[0160] Article 18 17. The method of claim 16, further comprising: determining that the first capacitance of the material differs from a baseline capacitance by more than a threshold difference; in response to the determination, identifying a size of an anomaly under the first electrode and the second electrode based on the first capacitance, the second capacitance, and the third capacitance; and providing an indication of the size of the anomaly under the first electrode and the second electrode via a user interface.

[0136]

[0161] Article 19 19. The method of any one of clauses 16 to 18, wherein the first electrode, the third electrode, and the fifth electrode are collinear, and the method further comprises applying a fourth voltage between the first electrode and the second electrode while the first electrode and the second electrode are disposed adjacent to a fourth region of the material, and detecting a fourth capacitance of the material based on a fourth response of the material to the fourth voltage; applying a fifth voltage between the third electrode and the fourth electrode while the third electrode and the fourth electrode are disposed adjacent to a fifth region of the material, and detecting a fifth capacitance of the material based on the fifth response of the material to the fifth voltage; applying a sixth voltage between the fifth electrode and the sixth electrode while the fifth electrode and the sixth electrode are disposed adjacent to a sixth region of the material, and detecting a sixth capacitance of the material based on the sixth response of the material to the sixth voltage.

[0137]

[0162] Article 20 19. The method of any one of clauses 16 to 18, wherein the first electrode, the third electrode, and the fifth electrode are not collinear.

[0138]

[0163] The description of the various advantageous configurations has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the examples to the disclosed exemplary forms. Numerous modifications and variations will be apparent to those skilled in the art. Moreover, various advantageous embodiments may exhibit different advantages over other advantageous embodiments. The selected embodiment(s) have been chosen and described to better explain the principles and practical applications of the embodiments and to facilitate others skilled in the art in understanding the disclosure of the various embodiments and various modifications suitable for the particular applications contemplated.

Claims

1. a first electrode; a second electrode surrounding the first electrode; a third electrode; a fourth electrode surrounding the third electrode; a fifth electrode; a sixth electrode surrounding the fifth electrode; and A sensing module configured to perform a function, the function comprising: applying a first voltage between the first electrode and the second electrode while the first electrode and the second electrode are disposed adjacent a first region of a material; sensing a first capacitance of the material based on a first response of the material to the first voltage; applying a second voltage between the third electrode and the fourth electrode while the third electrode and the fourth electrode are disposed adjacent a second region of the material; sensing a second capacitance of the material based on a second response of the material to the second voltage; applying a third voltage between the fifth electrode and the sixth electrode while the fifth electrode and the sixth electrode are disposed adjacent a third region of the material; sensing a third capacitance of the material based on a third response of the material to the third voltage; determining that the first capacitance of the material differs from a baseline capacitance by more than a threshold difference; In response to the determining, determining a size of an anomaly or a depth of the anomaly below the first electrode and the second electrode based on the first capacitance, the second capacitance, and the third capacitance; providing an indication of the size of the abnormality or the depth of the abnormality beneath the first electrode and the second electrode through a user interface; A sensing device comprising a sensing module including:

2. The sensing device of claim 1 , wherein the first electrode is coplanar with the second electrode.

3. The sensing device of claim 1 , wherein the first electrode and the second electrode both have mirror symmetry.

4. The sensing device of claim 1 further comprising a seventh electrode surrounding the first electrode.

5. A detection device as described in claim 4, wherein the seventh electrode surrounds the second electrode.

6. The sensing device of claim 1 , further comprising a circuit board, the first electrode and the second electrode being disposed on a first side of the circuit board.

7. The detection device described in claim 6, wherein the circuit board has a metal shielding layer on a second side of the circuit board opposite the first side.

8. The sensing device of claim 1 , further comprising a spacer configured to maintain a minimum distance between (i) the first electrode or the second electrode and (ii) the material.

9. A detection device as described in claim 1, wherein the first electrode, the third electrode, and the fifth electrode are on the same straight line.

10. A detection device as described in claim 1, wherein the first electrode, the third electrode, and the fifth electrode are not on the same straight line.

11. A detection device as described in claim 1, wherein the first electrode and the second electrode both have rotational symmetry.

12. 1. A method of operating a sensing device, comprising: applying a first voltage between a first electrode and a second electrode while the first electrode and the second electrode are disposed adjacent to a first region of the material, the second electrode surrounding the first electrode; sensing a first capacitance of the material based on a first response of the material to the first voltage; applying a second voltage between a third electrode and a fourth electrode while the third electrode and the fourth electrode are disposed adjacent to a second region of the material, the fourth electrode surrounding the third electrode; sensing a second capacitance of the material based on a second response of the material to the second voltage; applying a third voltage between a fifth electrode and a sixth electrode while the fifth electrode and a sixth electrode are disposed adjacent a third region of the material, the sixth electrode surrounding the fifth electrode; sensing a third capacitance of the material based on a third response of the material to the third voltage; determining that the first capacitance of the material differs from a baseline capacitance by more than a threshold difference; In response to the determining, determining a size of an anomaly or a depth of the anomaly under the first electrode and the second electrode based on the first capacitance, the second capacitance, and the third capacitance; and providing an indication of the size of the abnormality or the depth of the abnormality beneath the first electrode and the second electrode through a user interface.

13. The method of claim 12, wherein applying the first voltage includes applying the first voltage while the first electrode is not in contact with the material.

14. The method of claim 13, wherein applying the first voltage includes applying the first voltage while the second electrode is not in contact with the material.

15. The method of claim 12, wherein the first voltage is an AC voltage.

16. The method of claim 12, further comprising applying a fourth voltage between the first electrode and a seventh electrode simultaneously with applying the first voltage, the fourth voltage being applied while the seventh electrode is positioned adjacent to the material, and the seventh electrode surrounding the second electrode.

17. The method described in claim 16, wherein applying the fourth voltage includes applying the fourth voltage to shape the electric field generated between the first electrode and the second electrode.

18. the first electrode, the third electrode, and the fifth electrode are collinear, and the method includes: applying a fourth voltage between the first electrode and the second electrode while the first electrode and the second electrode are disposed adjacent a fourth region of the material; sensing a fourth capacitance of the material based on a fourth response of the material to the fourth voltage; applying a fifth voltage between the third electrode and the fourth electrode while the third electrode and the fourth electrode are disposed adjacent a fifth region of the material; sensing a fifth capacitance of the material based on a fifth response of the material to the fifth voltage; applying a sixth voltage between the fifth electrode and the sixth electrode while the fifth electrode and the sixth electrode are disposed adjacent a sixth region of the material; and The method of claim 12 , further comprising sensing a sixth capacitance of the material based on a sixth response of the material to the sixth voltage.

19. The method of claim 12 , wherein the first electrode, the third electrode, and the fifth electrode are not collinear.

20. The method of claim 12, wherein the first voltage is an AC voltage.

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