Matrix-addressable 2D eddy current array

Abstract

By applying matrix addressing technology to eddy current (EC) coil elements, the number of multiplexers in a two-dimensional EC probe can be reduced. Then, individual coil elements can be controlled to provide more robust EC testing capabilities. Leakage current issues can be addressed by using diode and biasing techniques.

Description

Technical Field

[0001] [Claim of Priority] This patent application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 493392, filed on March 31, 2023, entitled "ROW-COLUMN ADDRESSED(RCA) 2D EDDY CURRENT ARRAY(ECA)", which is hereby incorporated by reference in its entirety.

[0002] This document generally relates to non-destructive testing devices and techniques, such as facilitating eddy current inspection, and more specifically to devices and techniques comprising an eddy current array (ECA) sensor assembly having individually matrix-addressable sensor elements, although not limited thereto.

Background Art

[0003] Non-destructive testing (NDT) can refer to the use of one or more different techniques for inspecting areas on or within an object, for example, to confirm the presence of flaws or defects in the object being inspected, or to otherwise characterize the object being inspected. Certain non-destructive tests involve the use of an eddy current testing approach where electromagnetic energy is applied to the object by one or more probes, and the resulting induced current is detected on or within the object, and the value of the detected current (or related impedance) provides an indication of the structure of the object during testing such that it indicates the presence of cracks, voids, porosity, or other non-uniformities. Generally, an eddy current (EC) sensor includes one or more sensor elements, such as an induction coil that can be excited using an alternating current (AC) source. Such a coil (or other electromagnetic sensing element such as a Hall sensor) can be used to receive a signal indicative of an induced eddy current on or within the structure.

Summary of the Invention

Means for Solving the Problems

[0004] The examples described herein relate to matrix-addressable (RCA) type eddy current array (ECA) probes. An RCA ECA probe (RCA-type ECA probe) comprises at least one coil array including a plurality of coil elements, a diode array including a plurality of diodes coupled to the plurality of coil elements, and a multiplexer assembly for row and column addressing of the plurality of coil elements.

[0005] Embodiments described herein also relate to a method of activating a first set of coil elements in a matrix-addressable (RCA) type eddy current array (ECA) using a drive signal and a bias signal, wherein the bias signal activates at least one diode coupled to the first set of coil elements to operate in the forward region, and receiving an electrical representation of induced eddy currents using the RCA ECA.

[0006] The embodiments described herein further relate to probe assemblies for eddy current testing. The probe assembly comprises a first layer of a printed circuit board including a first set of metal traces to interleaved coil elements of a first coil array and a second coil array; a second layer of a printed circuit board including a second set of metal traces to interleaved coil elements of a first coil array and a second coil array; and a diode array coupled to the interleaved coil elements of a first coil array and a second coil array. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram illustrating an exemplary portion of a matrix-addressable (RCA) type eddy current array (ECA) probe. [Figure 2] This is a schematic diagram showing an example of an interleaved RCA ECA probe. [Figure 3] This is a schematic diagram showing one embodiment of a multi-input RCA ECA probe. [Figure 4A]This is a schematic diagram showing a first PCB layer having coil elements from two coil arrays. [Figure 4B] This is a schematic diagram showing a second PCB layer having coil elements from two coil arrays. [Figure 4C] This is a schematic diagram showing a two-layer PCB stack. [Figure 5] This is a schematic diagram showing similar parts of an RCE ECA probe. [Figure 6] This figure shows an exemplary portion of a coil array within a single resolution sensor. [Figure 7] This figure shows an exemplary portion of the coil array within a dual-resolution sensor. [Figure 8] This figure shows an example of array addressing for a dual-resolution sensor. [Modes for carrying out the invention]

[0008] The subject matter of this specification can be better understood by referring to the following description in conjunction with the accompanying drawings. The drawings are not intended to limit the claims contained herein. For clarity, not all elements may be labeled in all drawings. The drawings are not necessarily to scale and instead focus on illustrating embodiments, principles, and concepts. Accordingly, the features and advantages of this disclosure will be better revealed by the following detailed description of its embodiments in conjunction with the accompanying drawings.

[0009] Conventional eddy current (EC) systems are typically limited to one dimension. For example, a conventional EC probe with 16 transmitting coils and 16 receiving coils would be operated by two 16:1 multiplexers and associated drive and receive amplifier circuits. To then create a two-dimensional EC probe would require 32 16:1 multiplexers, which can be impractical in terms of cost and space.

[0010] As will be explained in more detail below, matrix addressing techniques can be applied to EC coil elements to reduce the number of multiplexers in a two-dimensional EC probe. Individual coil elements can then be controlled to provide more robust EC inspection capabilities. Leakage current problems can be addressed by using diode and biasing techniques, which will be explained in more detail below.

[0011] Figure 1 shows an exemplary portion of a matrix-addressable (RCA) eddy current array (ECA) probe 100. The RCA ECA probe (RCA-type ECA probe) 100 includes a coil array 102 containing a plurality of coil elements 102.1 to 102.n, a flexible wiring printed circuit board (PCB) 104 containing a plurality of diodes 104.1 to 104.n, and a multiplexer assembly 106. Figure 1 shows a simplified block diagram and schematic circuit diagram of the RCA ECA probe 100.

[0012] The coil array 102 may include a metallization layer such as a trace and is configured for use in EC testing. For example, the coil array 102 may be excited to generate electromagnetic energy for transmission into the object under test, and the coil array 102 may receive the resulting EC signal induced in the object under test. For example, the EC signal may be used to detect different types of defects in the object under test.

[0013] The coil array 102 includes multiple coil elements 102.1 to 102.n. In an RCA system, current can leak from one coil to another, which may also be called crosstalk. The coil array 102 may be coupled to multiple diodes 104.1 to 104.n provided on the flexible wiring PCB 104 to reduce (or eliminate) leakage current between coils. As shown in Figure 1, each of the diodes 104.1 to 104.n is provided for the corresponding coil among the multiple coil elements 102.1 to 102.n. The multiple diodes 104.1 to 104.n may be provided in series with their respective coil elements 102.1 to 102.n. The multiple diodes 104.1 to 104.n are provided on the flexible wiring PCB 104 to reduce the number of connectors (e.g., number of rows + number of columns).

[0014] The flexible wiring PCB 104 is coupled to a multiplexer assembly 106. The multiplexer assembly 106 may include a column multiplexer 108 and a row multiplexer 110. Individual coil elements 102.1 to 102.n can be addressed using the column multiplexer 108 and the row multiplexer 110. In an embodiment of an 8x8 coil array 102, the column multiplexer 108 may be provided as an 8x1 multiplexer, and the row multiplexer 110 may be provided as an 8x1 multiplexer. The column multiplexer 108 may be used to drive each coil element by providing a drive signal and a bias voltage. The bias voltage may flow through a plurality of diodes 104.1 to 104.n to reduce (or eliminate) leakage current between coils. The bias voltage may allow the full dynamic range of the drive signal within the forward region of the plurality of diodes 104.1 to 104.n. The generation of secondary current loops can be avoided by providing follow-through of the column signal path to the multiplexer assembly 106 of the column return path.

[0015] Figure 1 shows one coil array 102 for illustrative purposes, but multiple coil arrays can be provided. For example, four interleaved coil arrays can be provided, each capable of operating independently.

[0016] Figure 2 shows an example of an interleaved RCA ECA probe 200. As shown in Figure 2, the interleaved RCA ECA probe 200 includes four coil arrays for illustrative purposes, and other numbers of coil arrays may be provided. The coil arrays are RCA coil arrays as described herein. As will be described in more detail below, coil elements in different coil arrays may be provided on the same PCB layer. Also, the coil elements in each coil array may have overlapping footprints. In Figure 2, four coil elements 202-208 are highlighted for illustrative purposes.

[0017] Coil element 202 may be provided in a first coil array. Coil element 204 may be provided in a second coil array. Coil element 206 may be provided in a third coil array. Coil element 208 may be provided in a fourth coil array.

[0018] As shown, the coil element 202 of the first coil array is provided adjacent to the coil element 206 of the third coil array, and the footprint coil element 202 partially overlaps the coil element 204 of the second coil array and the coil element 208 of the fourth coil array. The coil element 204 of the second coil array is provided adjacent to the coil element 208 of the fourth coil array, and the footprint of the coil element 204 partially overlaps the coil element 202 of the first coil array and the coil element 206 of the third coil array. The coil element 206 of the third coil array is provided adjacent to the coil element 202 of the first coil array, and the footprint of the coil element 206 partially overlaps the coil element 204 of the second coil array and the coil element 208 of the fourth coil array. The coil element 208 of the fourth coil array is provided adjacent to the coil element 204 of the second coil array, and the footprint of the coil element 208 partially overlaps the coil element 202 of the first coil array and the coil element 206 of the third coil array.

[0019] The coil array is coupled to a flexible wiring PCB 210. The flexible wiring PCB 210 may include a plurality of diodes corresponding to the coil elements in the coil array to block leakage current, as discussed above.

[0020] The flexible wiring PCB 210 is coupled to a multiplexer assembly that includes column and row multiplexers for each coil array. For the first coil array (including coil element 202), column multiplexer 212 and row multiplexer 222 may be provided. For the second coil array (including coil element 204), column multiplexer 214 and row multiplexer 224 may be provided. For the third coil array (including coil element 206), column multiplexer 216 and row multiplexer 226 may be provided. For the fourth coil array (including coil element 208), column multiplexer 218 and row multiplexer 228 may be provided. The multiplexer assembly can be capable of collecting data for multi-directional orthogonal sensors. Each coil element within each array can be individually controlled using matrix addressing. Each coil array may be configurable in bridge (transmit and receive) mode and receive-only mode. In the receive-only mode, the bias voltage may be lower.

[0021] Figure 3 shows an example of a multi-input RCA ECA probe 300. The multi-input RCA ECA probe 300 includes, for illustrative purposes, two inputs that provide two sensors in this embodiment, and other numbers of inputs may be provided. The multi-input RCA ECA probe 300 may include four coil arrays (RCA coil arrays), namely, coil array 302, coil array 304, coil array 306, and coil array 308. The coil arrays 302 - 308 may be coupled to a plurality of diodes (not shown) corresponding to the coil elements within the coil array to block leakage current, as discussed above.

[0022] The coil elements in coil arrays 302 to 308 can be individually addressed as RCA arrays. Coil array 302 can be coupled to column multiplexer 312 and row multiplexer 322. Coil array 304 can be coupled to column multiplexer 314 and row multiplexer 324. Coil array 306 can be coupled to column multiplexer 316 and row multiplexer 326. Coil array 308 can be coupled to column multiplexer 318 and row multiplexer 328.

[0023] Each column multiplexer can be driven with a different signal. Column multiplexers 312, 314, 316, and 318 can be coupled to a drive multiplexer 332. The drive multiplexer 332 can drive each coil array 302-308 in three states: (1) drive + bias, (2) receive bias, and (3) ground (disabling each coil array).

[0024] In this embodiment, two inputs are provided. A first input multiplexer 340 may be coupled to each of the coil arrays 302-308 to provide a first input (IN#1). A second input multiplexer may be coupled to each of the coil arrays 302-308 to provide a second input (IN#2). Thus, the multi-input RCA ECA probe 300 can be configured to provide two configurable sensors in each time slot.

[0025] As described herein, coil arrays can be interleaved so that multiple coil arrays can share the same PCB layer. Figures 4A–4C show exemplary portions of two interleaved coil arrays.

[0026] Figure 4A shows a first PCB layer having coil elements from two coil arrays. Coil elements 402.1 to 402.8 belong to the first coil array, and coil elements 404.1 to 404.8 belong to the second coil array. The first PCB layer may be used to provide row addressing. In this embodiment, coil elements in the same row of the same coil array can share a common signal trace for row addressing. With respect to the first coil array, trace 406 is coupled to coil elements 402.1 and 402.2, trace 410 is coupled to coil elements 402.3 and 402.4, trace 414 is coupled to coil elements 402.5 and 402.6, and trace 418 is coupled to coil elements 402.7 and 402.8. With respect to the second coil array, trace 408 is coupled to coil elements 404.1 and 404.2, trace 412 is coupled to coil elements 404.3 and 404.4, trace 416 is coupled to coil elements 404.5 and 404.6, and trace 420 is coupled to coil elements 404.7 and 404.8.

[0027] Figure 4B shows a second PCB layer having coil elements from two coil arrays. Coil elements 402.1-402.8 from the first coil array and coil elements 404.1-404.8 from the second coil array are shown. The second PCB layer may be used for column addressing. In this embodiment, each coil element has its own independent signal trace for column addressing.

[0028] The central coil vias 412.1 to 412.8 and 414.1 to 414.8 connect the first PCB layer to the second PCB. For example, the central coil via 412.1 of the first coil element 402.1 of the first array connects the first PCB layer to the second PCB layer, and the central coil via 414.1 of the first coil element 404.1 of the second array connects the first PCB layer to the second PCB layer, and so on.

[0029] Figure 4C shows a two-layer PCB stack. As shown in Figure 4C, the first and second coil arrays are interleaved on the two-layer PCB stack. Parallel row and column addressing traces can be provided in close proximity to reduce noise.

[0030] By routing signals from multiple sides of the PCB stack, PCB routing is simplified, and the distance between row and column traces can be kept to a minimum. Figure 5 shows an exemplary portion of the RCE ECA probe 500. The RCE ECA probe 500 includes a PCB stack 502. The PCB stack 502 may include multiple interleaved coil arrays, as described above with reference to Figures 4A to 4C.

[0031] A first flexible wiring PCB 504 may be provided on one side of the PCB stack 502. The first flexible wiring PCB 504 may include a plurality of diodes corresponding to a subset (e.g., half) of the coil elements in the PCB stack 502. A first connector 504 may be coupled to the first flexible wiring PCB 504. The first connector 504 may be coupled to a multiplexer assembly (not shown) as described above.

[0032] A second flexible wiring PCB 508 may be provided on the other side of the PCB stack 502. The second flexible wiring PCB 508 may include a plurality of diodes corresponding to a subset (e.g., half) of the coil elements in the PCB stack 502. A second connector 510 may be coupled to the second flexible wiring PCB 508. The second connector 510 may be coupled to a multiplexer assembly (not shown) as described above.

[0033] Figure 6 shows an exemplary portion of a composite sensor structure. The first sensor structure comprises a coil element 602 of a first coil array, a coil element 604 of a second coil array, a coil element 606 of a third coil array, and a coil element 608 of a fourth coil array. The second sensor structure comprises a coil element 612 of a first coil array, a coil element 614 of a second coil array, a coil element 616 of a third coil array, and a coil element 618 of a four-coil array. In some embodiments, a drive multiplexer can be used to energize any of the four coil elements simultaneously or individually on different time slots, and the four coil elements can be used in reception. A typical configuration of these four coil assemblies is to use opposing coils in transmission and the other two coils in differential reception to produce a single composite sensor with a sensitive spot at the center of the four coil elements. A composite sensor can be generated from this coil assembly using other techniques, such as transmitting alternately through each of the four coil elements and acquiring the received signal through each of the four coil elements for each transmission coil selection, in order to capture the complete interaction matrix between the four coil elements. Once the complete interaction matrix is ​​obtained, any sensor configuration with the four coil elements can be obtained through signal processing.

[0034] As described herein, RCA ECA probes may be offered in different resolutions. Figure 6 shows an exemplary portion of a coil array in a single-resolution probe 600. A single-resolution probe 600 may include four coil arrays, with two coil arrays sharing a two-layer PCB stack. Thus, a single-resolution probe 600 may include a first two-layer PCB stack for the first and second coil arrays (e.g., as shown in Figures 4A-4C), and a single-resolution probe 600 may include a second two-layer PCB stack for the third and fourth coil arrays (e.g., as shown in Figures 4A-4C). The combined sensitive regions may have sufficient overlap between the coil elements to ensure good coverage within the probe.

[0035] Some defects, such as short circuits, may be suitable for detection by a dual-resolution probe. Figure 7 shows an exemplary portion of a coil array within a dual-resolution probe 700. The dual-resolution probe 700 may be supplied on eight PCB layers and four PCB stacks. The dual-resolution probe 700 may include four coil arrays distributed on four PCB stacks. A first coil array may be supplied using coil components on a first PCB stack and a second PCB stack. A second coil array may be supplied using coil components on a first PCB stack and a second PCB stack. A third coil array may be supplied using coil elements on a third PCB stack and a fourth PCB stack. A fourth coil array may be supplied using coil elements on a third PCB stack 826 and a fourth PCB stack.

[0036] Figure 8 shows an exemplary portion of the array addressing of a dual-resolution sensor. The first sensor array 802 may be provided on first and second PCB layers and includes coil connections for the first coil array (RCA#1) and the second coil array (RCA#2), where in this embodiment each coil array is an 8×8 array. As shown, the first sensor array 802 includes rows 1-8 and columns 1,3,5,7 of the first and second coil arrays. A first set of traces 804 may be provided on one side of the first sensor array 802 for rows 1-8 and columns 1,3. A second set of traces 806 may be provided on the second side of the first sensor array 802 for rows 1-8 and columns 5,7.

[0037] A second sensor array 812 may be provided on third and fourth PCB layers and includes coil connections for a first coil array (RCA#1) and a second coil array (RCA#2). The second sensor array 812 includes rows 1-8 and rows 2, 4, 6, and 8 of the first and second coil arrays. A first set of traces 814 may be provided on one side of the second sensor array 812 for rows 1-8 and columns 2 and 4. A second set of traces 816 may be provided on a second side of the second sensor array 812 for rows 1-8 and columns 6 and 8.

[0038] A third sensor array 824 may be provided on fifth and sixth PCB layers and includes coil connections for a third coil array (RCA#3) and a fourth coil array (RCA#4). A third sensor array 822 includes rows 1-8 and columns 2, 4, 6, and 8 of the third and fourth coil arrays. A first set of traces 824 may be provided on one side of the third sensor array 822 for rows 1-8 and columns 2 and 4. A second set of traces 826 may be provided on a second side of the third sensor array 812 for rows 1-8 and columns 6 and 8.

[0039] A fourth sensor array 832 may be provided on the seventh and eighth PCB layers and includes coil connections for a third coil array (RCA#3) and a fourth coil array (RCA#4). As shown, the fourth sensor array 832 includes rows 1-8 and columns 1, 3, 5, and 7 of the third and fourth coil arrays. A first set of traces 804 may be provided on one side of the fourth sensor array 832 for rows 1-8 and columns 1 and 3. A second set of traces 836 may be provided on a second side of the fourth sensor array 832 for rows 1-8 and columns 5 and 7.

[0040] In this embodiment, the overlapping sensor arrays 802, 812, 822, and 832 can share the same coil array connection because the first and second coil arrays may not operate simultaneously. Therefore, even with a dual-resolution array, this embodiment can use only four independent and interleaved coil arrays.

[0041] The processing (for example, performing one or more of the methods described herein) may be implemented in hardware, software, or a combination of both. The processing may be performed in a computer program running on a programmable computer / machine, each including a processor, a storage medium, or other products readable by the processor (including volatile and non-volatile memory and / or memory elements), at least one input device, and one or more output devices. The program code may be applied to data input using the input devices to perform the processing and generate output information. Memory may include a machine-readable medium storing one or more sets of data structures or instructions (e.g., software) that embody or utilize one or more of the techniques or functions described herein.

[0042] In some embodiments, the system may be embodied by one or more programmable processors that execute one or more computer programs to perform the functions of the system. In some other embodiments, all or part of the system may be implemented as special-purpose logic circuits (e.g., field-programmable gate arrays (FPGAs) and / or application-specific integrated circuits (ASICs)). In some other embodiments, all or part of the system may be implemented using electronic hardware circuits that include, for example, at least one of electronic devices such as a processor, memory, programmable logic devices, or logic gates.

[0043] In one embodiment, the methods described herein are not limited to the specific examples described. In further embodiments, rather, any of the method steps may be rearranged, combined, deleted, or performed in parallel or sequentially, as necessary, to achieve the above results.

[0044] In some embodiments, the system may be executed by a data processing device (e.g., a programmable processor, a computer, or multiple computers) or implemented to control the operation of a data processing device (e.g., a programmable processor, a computer, or multiple computers) via a computer program product (e.g., a non-temporary machine-readable storage medium such as a non-temporary computer-readable medium). In certain embodiments, each such program may be implemented in a high-level procedural programming language or an object-oriented programming language for communication with the computer system. However, in certain other embodiments, the program may be implemented in assembly or machine language. In some embodiments, the language may be a compiled or interpreted language and may be deployed in any form, including as a standalone program or as modules, components, subroutines, or other units suitable for use in a computing environment. In some other embodiments, the computer program may be deployed to run on one or more computers at one site, or distributed across multiple sites and interconnected by a communication network.

[0045] The methods and apparatus of this disclosure may take at least partly the form of program code (i.e., instructions) embodied on a tangible, non-temporary medium such as a floppy diskette, CD-ROM, hard drive, random-access or read-only memory, or any other machine-readable storage medium. When the program code is loaded onto and executed on a machine such as the computer shown in Figure 4, the machine becomes an apparatus for practicing examples of the subject matter of the present invention. When implemented on one or more general-purpose processors, the program code, in combination with such processors, provides a unique apparatus that operates similarly to a particular logic circuit. Thus, a general-purpose digital machine can be converted into a dedicated digital machine. In some other embodiments, the non-temporary machine-readable medium may include, but is not limited to, a hard drive, compact disk, flash memory, non-volatile memory, volatile memory, magnetic diskette, etc., but does not include temporary signals themselves.

[0046] The terms “machine-readable medium” or “machine-readable storage medium” may include any medium capable of storing, encoding, or holding instructions for execution by a machine, and capable of causing a machine to perform one or more of the technologies of this disclosure, or storing, encoding, or holding data structures used by or associated with such instructions. Examples of non-limiting machine-readable mediums include solid-state memory, as well as optical and magnetic media. Therefore, machine-readable mediums are not transient propagating signals. Specific examples of aggregated machine-readable mediums include non-volatile memory such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices, magnetic or other phase-shifting or state-shifting memory circuits, magnetic disks such as internal hard disks and removable disks, magneto-optical disks, and CD-ROM and DVD-ROM disks.

[0047] While the above examples have been described in some detail for the purpose of clarifying understanding, it will be clear that certain changes and modifications can be made within the scope of the appended claims. The scope of the present invention is limited only by the claims, and the invention encompasses a number of substitutes, modifications, and equivalents. In order to provide a complete understanding of the invention, many specific details are described in the above specification. These details are provided for illustrative purposes, and the invention can be practiced in accordance with the claims without some or all of these specific details. For clarification, technical materials known in the art related to the invention are not described in detail so as not to unnecessarily obscure the invention. Therefore, the above implementations should be considered illustrative and not limiting, and the invention is not limited to the details given herein and can be modified within the scope of the appended claims and equivalents.

[0048] Various embodiments of the present disclosure are described with reference to the accompanying drawings. It should be understood that these exemplary embodiments are provided solely to enable those skilled in the art to better understand the present disclosure and then to further practice the invention, and are not intended to limit the scope of the present disclosure in any way. It should be noted that these drawings and descriptions are presented only as examples of embodiments, and based on this description, alternative embodiments may be envisioned that may have structures and methods as disclosed herein, and such alternative embodiments may be used without departing from the principles of the present disclosure claimed in this disclosure.

[0049] It should be noted that the flowcharts and block diagrams in the figures may illustrate devices, methods, architectures, functions, and operations that can be executed by computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, program segment, or part of code, which may contain one or more executable instructions for performing a specified logical function. It should be further noted that in some alternative implementations, the functions indicated in the blocks may occur in an order different from the order illustrated in the figures. For example, two blocks shown consecutively may be executed substantially in parallel or in reverse order, depending on the functions involved. It should be further noted that each block and combination of blocks in a block diagram or flowchart may be implemented by a dedicated hardware-based system for performing a specified function or operation, or by a combination of dedicated hardware and computer instructions.

[0050] The terms “equipped with,” “including,” and their derived and similar expressions as used herein should be understood to be open (i.e., “including” is not limited to these). The term “based on” means “at least partially based on,” the term “one embodiment” means “at least one embodiment,” and the term “another embodiment” indicates “at least one further embodiment.” Relevant definitions of other terms are provided.

[0051] In this specification, the term “or” is used to refer to a non-exclusive OR, such that “A or B” includes “A but not B,” “B but not A,” and “A and B.” In this specification, the terms “include” and “therefore” are used as plain English equivalents of the terms “equipped with” and “therefore.” Furthermore, in the claims set forth below, the terms “include” and “equipped with” are not limiting; that is, any system, device, article, composition, formulation, or process that includes elements in addition to those listed after such terms in a claim is still considered to be within the scope of that claim. Moreover, in the claims set forth below, terms such as “first,” “second,” and “third” are used merely as labels and are not intended to impose numerical requirements on their objects.

[0052] Examples of methods described herein may be at least partially machine or computer implements. Some examples may include computer-readable or machine-readable media encoded with instructions that can be operated to constitute an electronic device and implement the methods described in the above examples. Implementations of such methods may include code such as microcode, assembly language code, or higher-level language code. Such code may include computer-readable instructions for implementing various methods. The code may form part of a computer program product. Furthermore, in one example, the code may be tangibly stored in one or more volatile, non-transient, or non-volatile tangible computer-readable media, such as during execution or at other times. Examples of these tangible computer-readable media include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memory (RAM), and read-only memory (ROM).

[0053] The above description is intended to be illustrative and not restrictive. For example, the examples (or one or more embodiments thereof) described above may be used in combination with one another. Other implementations may be used by those skilled in the art who have considered the above description. The abstract is provided to enable the reader to quickly confirm the nature of the technical disclosure. The abstract is submitted with the understanding that it is not to be used to interpret or limit the scope or meaning of the claims. Also, in the above detailed description, various features may be grouped together in order to streamline the disclosure. This should not be interpreted as meaning that any disclosed features not claimed are essential to any patent claim. Rather, the subject matter of the invention may be less than all the features of a particular disclosed implementation. For this reason, the claims below are incorporated into the detailed description as examples or implementations, and each claim is intended to exist independently as a separate implementation, and such implementations may be combined with one another in various combinations or permutations. The scope of the invention should be determined by referring to the appended claims, together with the entire scope of equivalents to which such claims are entitled. The following is an addendum to this disclosure. [Note 1] A matrix addressable (RCA) type eddy current array (ECA) probe comprising: at least one coil array including a plurality of coil elements; a diode array including a plurality of diodes coupled to the plurality of coil elements; and a multiplexer assembly for addressing the rows and columns of the plurality of coil elements. [Note 2] The diode array is provided on a flexible printed circuit board (PCB) coupled to the at least one coil array, as described in Note 1, for the RCA-type ECA probe. [Note 3] The RCA-type ECA probe of Note 1, wherein the first portion of the diode array is provided on a first flexible printed circuit board (PCB) coupled to the first side of the at least one coil array, and the second portion of the diode array is provided on a second flexible PCB coupled to the second side of the at least one coil array. [Note 4] The RCA-type ECA probe of Note 1, wherein at least one of the plurality of diodes is coupled in series with at least one of the plurality of coil elements. [Note 5] The RCA-type ECA probe of Note 1, wherein the multiplexer assembly is configured in transmission mode to drive a column multiplexer with a drive signal and a bias signal, and at least one of the plurality of diodes is configured to operate in the forward region based on the bias signal. [Note 6] The RCA-type ECA probe of Note 1, wherein the at least one coil array includes a first coil array and a second coil array interleaved on a first layer and a second layer of the PCB. [Note 7] The first layer includes signal traces for row addressing to the coil elements of the first and second coil arrays, as specified in Note 6, for the RCA-type ECA probe. [Note 8] At least two coil elements of the first coil array in the same row use a common signal trace for row addressing, RCA-type ECA probe as described in Note 7. [Note 9] The second layer is an RCA-type ECA probe as described in Note 6, including signal traces for column addressing to the coil elements of the first and second coil arrays. [Note 10] The RCA-type ECA probe according to Note 1, wherein the at least one coil array includes a first coil element and a second coil element, the first footprint of the first coil element at least partially overlaps with the second footprint of the second coil element. [Note 11] The RCA-type ECA probe according to Note 1, wherein the at least one coil array includes four coil arrays. [Note 12] A method comprising using a drive signal and a bias signal to activate a first set of coil elements in a matrix-addressable (RCA) type eddy current array (ECA), wherein the bias signal causes at least one diode coupled to the first set of coil elements to operate in the forward region, and the RCA type ECA to receive an electrical representation of induced eddy currents. [Note 13] The method of Note 12, wherein at least the diode is provided on a flexible printed circuit board (PCB) coupled to the first set of coil elements. [Note 14] The method of Note 12, wherein the coil elements of the first set are provided in a first sensor configuration, and the method further comprises operating the coil elements of the second set in a second sensor configuration. [Note 15] The method of Note 12, wherein at least the diode is coupled in series with one of the coil elements of the first set. [Note 16] The method of Note 12, further comprising connecting the second set of coil elements in the RCA-type ECA to ground. [Note 17] The method of Note 12, wherein the coil elements of the first set are provided in a first coil array and a second coil array interleaved on a first layer and a second layer of the PCB. [Note 18] The method of Note 17, wherein the first layer includes signal traces for row addressing to the coil elements of the first coil array and the second coil array, and at least two coil elements of the first coil array in the same column use a common signal trace for row addressing. [Note 19] A probe assembly for eddy current testing, comprising: a first layer of a printed circuit board including a first set of metal traces for interleaved coil elements of a first coil array and a second coil array; a second layer of the printed circuit board including a second set of metal traces for the interleaved coil elements of the first coil array and the second coil array; and a diode array coupled to the interleaved coil elements of the first coil array and the second coil array. [Note 20] The probe assembly of Note 19, wherein a diode array is provided on a flexible printed circuit board coupled to the printed circuit board.

Claims

1. A matrix-addressable (RCA) type eddy current array (ECA) probe, A coil array comprising multiple coil elements, A diode array including a plurality of diodes coupled to the plurality of coil elements, An RCA-type ECA probe comprising a multiplexer assembly for addressing the rows and columns of the plurality of coil elements.

2. The RCA-type ECA probe according to claim 1, wherein the diode array is provided on a flexible printed circuit board (PCB) coupled to the at least one coil array.

3. The RCA-type ECA probe according to claim 1, wherein a first portion of the diode array is provided on a first flexible printed circuit board (PCB) coupled to the first side of the at least one coil array, and a second portion of the diode array is provided on a second flexible PCB coupled to the second side of the at least one coil array.

4. The RCA-type ECA probe according to claim 1, wherein at least one of the plurality of diodes is coupled in series with at least one of the plurality of coil elements.

5. The RCA-type ECA probe according to claim 1, wherein the multiplexer assembly is configured in transmission mode to drive a column multiplexer with a drive signal and a bias signal, and at least one of the plurality of diodes is configured to operate in the forward region based on the bias signal.

6. The RCA-type ECA probe according to claim 1, wherein the at least one coil array includes a first coil array and a second coil array interleaved on a first layer and a second layer of the PCB.

7. The RCA-type ECA probe according to claim 6, wherein the first layer includes signal traces for row addressing to the coil elements of the first coil array and the second coil array.

8. The RCA-type ECA probe according to claim 7, wherein at least two coil elements of the first coil array in the same row use a common signal trace for row addressing.

9. The RCA-type ECA probe according to claim 6, wherein the second layer includes signal traces for column addressing to the coil elements of the first coil array and the second coil array.

10. The RCA-type ECA probe according to claim 1, wherein the at least one coil array includes a first coil element and a second coil element, and the first footprint of the first coil element at least partially overlaps with the second footprint of the second coil element.

11. The RCA-type ECA probe according to claim 1, wherein the at least one coil array includes four coil arrays.

12. Using a drive signal and a bias signal, the method involves activating a first set of coil elements in a matrix-addressable (RCA) type eddy current array (ECA), wherein the bias signal causes at least one diode coupled to the first set of coil elements to operate in the forward region. A method comprising receiving an electrical representation of an induced eddy current using the aforementioned RCA-type ECA.

13. The method according to claim 12, wherein at least the diodes are provided on a flexible printed circuit board (PCB) coupled to the first set of coil elements.

14. The coil element of the first set is provided in a first sensor configuration, and the method is The method according to claim 12, further comprising operating a second set of coil elements in a second sensor configuration.

15. The method according to claim 12, wherein at least the diode is coupled in series with one of the coil elements of the first set.

16. The method according to claim 12, further comprising connecting a second set of coil elements in the RCA-type ECA to ground.

17. The method according to claim 12, wherein the first set of coil elements are provided in a first coil array and a second coil array interleaved on a first layer and a second layer of the PCB.

18. The first layer includes signal traces for row addressing to the coil elements of the first and second coil arrays. The method according to claim 17, wherein at least two coil elements of the first coil array in the same row use a common signal trace for row addressing.

19. A probe assembly for eddy current testing, A first layer of a printed circuit board including a first set of metal traces for interleaved coil elements of a first coil array and a second coil array, A second layer of the printed circuit board including a second set of metal traces for the interleaved coil elements of the first coil array and the second coil array, A probe assembly comprising a diode array coupled to the interleaved coil elements of the first coil array and the second coil array.

20. The probe assembly according to claim 19, wherein a diode array is provided on a flexible printed circuit board coupled to the printed circuit board.

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