Inspection device and method for verifying alignment and / or protuberance of test probes in respect of PCB test points

Abstract

The present disclosure relates to an inspection device and method for verifying the alignment and / or protuberance of an assembly of test probes with corresponding test points on a previously probed printed circuit board (PCB). The device comprises a base for receiving the PCB, a camera for capturing images above the PCB, and a linear motion mechanism enabling camera, or PCB, movement along a two-dimensional X-Y plane. An electronic data processor controls the motion mechanism to move the camera, or the PCB, along a predefined image acquisition path, actuates the camera to capture images of each test point, and outputs the captured images for alignment verification. The device ensures precise alignment of test probes with test points, improving subsequent testing accuracy and reducing errors in PCBs. This device enhances quality control by providing a reliable and automated method for verifying probe alignment, thereby optimizing manufacturing efficiency and reducing defects in PCB testing processes.

Description

D E S C R I P T I O NINSPECTION DEVICE AND METHOD FOR VERIFYING ALIGNMENT AND / OR PROTUBERANCE OF TEST PROBES IN RESPECT OF PCB TEST POINTSTECHNICAL FIELD

[0001] The present invention relates to the field of printed circuit board (PCB) testing, and more particularly to a device and method for verifying test probes in their positioning, protuberance, and / or alignment with corresponding test points (TPs) on a PCB, by way of verification of the positioning and / or depth of corresponding indentation marks made by the test probes on the TPs.BACKGROUND

[0002] The continuous advancement of technology in the electronics sector has led to the accelerated miniaturization of printed circuit boards (PCBs), resulting in increased complexity and a higher number of components. Consequently, there has been a significant rise in the density of test points required for performing functional and connectivity tests. This evolution, combined with the growing complexity of electronic system functionalities and the demand for high-quality standards, has introduced new challenges in the development and inspection of testing systems, such as test presses and in-circuit test (ICT) bed-of-nails fixtures.

[0003] To ensure proper functionality and connectivity, PCBs undergo various testing processes, including in-circuit testing, functional testing, and boundary scan testing. Among these, ICT is one of the most widely used methods due to its ability to quickly and efficiently verify electrical connections, component values, and circuit integrity.

[0004] In-circuit testing is a widely used method for assessing the functionality and integrity of electronic circuits, ensuring compliance with design specifications and quality standards. This non-destructive testing technique involves applying electrical probes to specific test points on a printed circuit board (PCB) to verify component placement, continuity, resistance, capacitance, and potential defects such as opencircuits, short circuits, or faulty components. ICT plays a crucial role in quality control during manufacturing, reducing the likelihood of defective products reaching the market. ICT systems usually rely on test fixtures with an array of spring-loaded probe nails (or needles or pins) that make contact with predefined test points on the PCB. The accuracy of these contact points is crucial for obtaining reliable test results. However, as PCBs become more complex, the density of TPs has increased significantly, making precise alignment of ICT probes a growing challenge.

[0005] One of the primary issues in ICT is ensuring that the test probes align accurately with the designated TPs on a PCB. Even minor misalignments can lead to test failures, generating false negatives or unreliable readings. Misalignment can be caused by various factors, including mechanical tolerances in fixture manufacturing, PCB warping, or inconsistencies in PCB fabrication. Since each bed-of-nails is personalized for each PCB, its production is still a very manual labour, which is prone to human errors that can lead to misalignments. Such inaccuracies not only increase manufacturing costs but also reduce the overall reliability of the testing process, leading to defective units being misclassified or requiring rework. This results in production inefficiencies, increased scrap rates, and higher operational costs.

[0006] In addition, another significant issue in ICT is ensuring that the test probes are positioned at an appropriate vertical height, i.e. their protuberance, so as to apply a correct and controlled contact force to the PCB. Insufficient contact force may result in unstable electrical connections and unreliable measurements, whereas excessive probe pressure can damage the PCB by removing or deforming conductive layers, protective coatings, or structural materials. Such damage may be irreversible and can compromise the electrical integrity and long-term reliability of the PCB, thereby causing substantial production losses and associated economic impact, particularly in situations where the internal spring mechanism of the test probes does not operate correctly.

[0007] Traditionally, the verification of probe alignment regarding TPs has been performed manually by operators using microscopes. This approach involves visually inspecting the placement of the test probes relative to the TPs. However, this method presents several drawbacks. First, it is highly dependent on the experience and skill of the operator, making it inherently subjective and prone to human error. Second, as PCBcomplexity increases and the number of TPs grows into the hundreds or even thousands, manual verification becomes increasingly impractical and time-consuming. Third, the manual process does not provide a systematic and objective way to record and analyse alignment deviations, making it difficult to track performance trends and optimize test fixture designs over time. With this manual approach, reaching the needed detail level would take a considerable amount of time, in the magnitude of several days per PCB.

[0008] Additionally, as PCBs evolve with smaller components, higher densities, and more intricate designs, the margin for error in probe alignment continues to decrease. In high-volume production environments, the inability to quickly and accurately verify probe alignment can lead to significant delays and production bottlenecks. Any undetected misalignment in the testing phase may result in defective products reaching the market, potentially leading to customer dissatisfaction, product recalls, or compliance failures in highly regulated industries such as automotive, aerospace, and medical devices.

[0009] Given these limitations, there is a clear need for an automated solution that can accurately and objectively verify the alignment of probes in a scalable manner, before production start. An automated approach would eliminate the inconsistencies associated with manual inspection, reduce dependence on skilled labour, and enable real-time data collection for quality control and process optimization. By integrating automation into the TP alignment verification process, manufacturers can enhance testing efficiency, reduce false negatives, improve product reliability, and lower overall production costs.

[0010] The present invention addresses these challenges by providing a novel device and method for the automated verification of probe alignment in ICT systems. The proposed solution ensures that test probes are precisely positioned before functional and connectivity tests are performed, thereby improving the accuracy and reliability of subsequent testing processes. This innovation represents a significant advancement in PCB manufacturing and quality control, enabling greater efficiency, consistency, and scalability in electronic testing environments.

[0011] Document KR20220128206A discloses a method for testing PCB chips using a flying probe tester. This flying probe tester automatically moves to X, Y, and Z axes toautomatically measure inductance, capacitance, and resistance of each chip for a PCB to which a chip is mounted and includes a pin tool for automatically exchanging a contact pin for measuring various chips such as a type, direction, and the like of chips to be measured.

[0012] Document CN114353676A discloses a device for automatically measuring the height of a surface-mounted chip. The device comprises a base configured to support a printed circuit board (PCB) to be measured, a laser range finder positioned above the PCB, a charge-coupled device (CCD) camera arranged above the laser range finder, a programmable logic controller (PLC), and a host computer. More than three reference mark points are provided on the base, defining an area in which the PCB under test is positioned. The document further discloses a method for automatically measuring the height of a mounted chip using the above device. The method and device enable automated chip height measurement after chip mounting. In addition, the device may be used to detect PCB warpage.

[0013] Document CN114022436B discloses a method, apparatus, inspection equipment, and storage medium for inspecting printed circuit boards (PCBs). The disclosed PCB inspection method comprises acquiring, via an image acquisition device, a test image of a PCB to be inspected, the test image including a plurality of reference points. A standard image corresponding to the test image is then determined, and an offset of the reference points is calculated based on a comparison between the test image and the standard image. The position of the test image relative to the standard image is subsequently adjusted according to the calculated offset.

[0014] These facts are disclosed in order to illustrate the technical problem addressed by the present disclosure.GENERAL DESCRIPTION

[0015] The present disclosure relates to the field of printed circuit board (PCB) testing, and more particularly to a device and method for verifying test probes in their positioning, protuberance, and / or alignment with corresponding test points (TPs) on a PCB, by way of verification of the positioning and / or depth of corresponding indentationmarks made by the test probes on TPs, prior to mass production involving functional, in-circuit, or parametric testing, thereby improving the efficiency and accuracy of the production line. The disclosure enables probe-to-test-point alignment / protuberance control to establish reliable electrical connections, thereby improving the efficiency and accuracy of subsequent automated testing procedures.

[0016] Also, the disclosure improves in damage detection caused by incorrect probe configuration, including removal or deformation of conductive layers, protective coatings, or structural materials, which may be irreversible and can compromise the electrical integrity and long-term reliability of the PCB.

[0017] The disclosed technology is particularly relevant in quality control, automated test equipment (ATE) calibration, and PCB manufacturing processes across various industries, including consumer electronics, automotive, telecommunications, and aerospace.

[0018] In the context of the present disclosure, verifying a test probe's protuberance may include determining whether the probe projects by an insufficient amount (e.g. because the probe is too short to establish a stable and reliable electrical contact with the corresponding test point) and / or whether the probe projects by an excessive amount (e.g. because the probe is too long or because its internal spring mechanism does not retract properly). In the latter, the probe may exert an excessive contact force on the PCB, which can damage conductive tracks, pads, protective layers, or other structural portions of the board, thereby compromising its integrity and reliability.

[0019] An aspect of the present disclosure relates to an inspection device for verifying the alignment and / or protuberance of an assembly of test probes with corresponding test points on a PCB previously probed with said assembly of test probes, comprising: a base for receiving the PCB;a camera for capturing images and / or depth of the PCB from above the PCB;a linear motion mechanism for movement of the camera along a two-dimensional X-Y plane in respect of the PCB, or a linear motion mechanism for movement of the PCB along a two-dimensional X-Y plane in respect of the camera; andan electronic data processor configured to:operate the linear motion mechanism to move the camera, or the PCB, along an acquisition path within the two-dimensional X-Y plane;actuate the camera to capture a plurality of images and / or a plurality of depth measurements, each image and / or depth measurement comprising one or more test points along the acquisition path; andoutput the captured images and / or depth measurements for verification of the alignment and / or protuberance of the assembly of test probes with the corresponding test points on the PCB.

[0020] In an embodiment, the electronic data processor is further configured to process a captured image and / or depth measurement of each test point to be verified for recognition of an indentation mark left by a test probe on said each test point.

[0021] In an embodiment, the electronic data processor is further configured to process the captured image and / or depth measurement of each test point to be verified for recognition of the location of the indentation mark.

[0022] In an embodiment, the electronic data processor is further configured to apply a machine-learning model to the outputted captured images and / or depth measurements for recognising the indentation mark left by a test probe on said each test point.

[0023] In an embodiment, the electronic data processor is configured to calculate a distance between a centre of each test point and the location of the indentation mark on said each test point.

[0024] In an embodiment, the electronic data processor is further configured to compare the distance between a centre of each test point and the location of the indentation mark with a predetermined distance threshold.

[0025] In an embodiment, the test point is classified as non-compliant if the distance meets or exceeds the predefined threshold; and compliant if the deviation is below the threshold.

[0026] In an embodiment, the electronic data processor is further configured to process the depth measurement of said each test point for recognition of a maximum depth of the indentation mark.

[0027] In an embodiment, the electronic data processor is further configured to compare the maximum depth of each said test point with a predetermined depth threshold, in particular configured to compare the maximum depth of each said test point against a predetermined depth threshold range.

[0028] In an embodiment, the camera is an optical camera, in particular a camera with telecentric lens.

[0029] In an embodiment, the camera is a 3D camera, in particular a laser camera configured to provide a 3D-point cloud.

[0030] In an embodiment, the electronic data processor is further configured for simultaneous or sequential verification of alignment and protuberance of the assembly of test probes.

[0031] In an embodiment, the inspection device further comprises a user interface for receiving manual user input, in particular for receiving an alignment and / or depth threshold.

[0032] In an embodiment, the inspection device further comprises a display, wherein the electronic data processor is configured to present in said display to a user, a calculated distance and / or depth of the indentation mark for each test point.

[0033] In an embodiment, the electronic data processor is further configured to generate a graphical overlay on each captured image, said graphical overlay visually indicating the calculated distance and / or depth for each test point.

[0034] In an embodiment, the electronic data processor is further configured to generate a report comprising a calculated distance and / or depth of the indentation mark for each test point; preferably comprising an indication of whether the calculated distance exceeds a predetermined distance threshold and / or an indication of whether the depth exceeds a predetermined depth threshold.

[0035] In an embodiment, said base is positioned within a support frame.

[0036] In an embodiment, the inspection device further comprises a PCB mounting for holding the PCB in place; wherein the PCB mounting is fixed to the base.

[0037] In an embodiment, the PCB mounting is adjustable for different PCB dimensions.

[0038] In an embodiment, the inspection device further comprises an illumination module attached to the camera and configured for moving with the camera for enhancing quality of the image captured.

[0039] In an embodiment, the illumination module is an adjustable light source configured to adapt its intensity based on ambient lighting conditions.

[0040] In an embodiment, the inspection device further comprises a PCB feeding system for automatic positioning of the PCB within the base for inspection.

[0041] In an embodiment, the inspection device further comprises a second camera positioned opposite to the first camera in respect of the PCB, wherein the electronic data processor is configured to actuate simultaneously the two cameras to capture images of two opposite faces of the PCB during inspection.

[0042] In an embodiment, the camera is positioned above the PCB and is configured to capture a single image covering an entire PCB upper surface for inspection.

[0043] In an embodiment, the second camera is positioned below the PCB and is configured to capture a single image covering an entire PCB lower surface for inspection.

[0044] In an embodiment, the linear motion mechanism comprises:linear rails for providing a guided path for linear motion along a X direction;a transverse guide mounted on the linear rails and comprising a support movable along a Y direction within said transverse guide;at least one motor-driven actuator for movement of the transverse guide along the linear rails and for moving the camera along a Y direction within said transverse guide.

[0045] In an embodiment, the camera is mounted onto the support.

[0046] In an embodiment, the PCB is mounted onto the support.

[0047] In an embodiment, the assembly of test probes is an ICT bed-of-nails test probe assembly.

[0048] An aspect of the present disclosure also relates to a method for verifying the alignment and / or protuberance of an assembly test probes with corresponding test points on a PCB previously probed with said assembly of test probes, comprising:providing an inspection device;operating the linear motion mechanism to move the camera, or the PCB, along an acquisition path within the two-dimensional X-Y plane;actuate the camera to capture an image and / or depth measurement comprising one or more test points along the acquisition path; andoutput the captured images and / or depth measurements for verification of the alignment and / or protuberance of the assembly of test probes with the corresponding test points on the PCB.BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The following figures provide preferred embodiments for illustrating the disclosure and should not be seen as limiting the scope of invention.

[0050] Figure 1: Schematic representation of an embodiment of an inspection device for verifying the correct alignment of test probes with corresponding test points on a PCB, wherein:1 represents an inspection device;2 represent a support frame;3 represents a base;4 represents a PCB mounting;5 represents a linear motion mechanism;6 represents a camera.

[0051] Figure 2: Schematic representation of a printed circuit board (PCB) and an in-circuit test (ICT) probe, specifically illustrating a bed-of-nails fixture making electrical contact with designated test points for ICT; wherein:7 represents a bed-of-nails test probe assembly;8 represents a single test probe of the bed-of-nails test probes;9 represents a printed circuit board (PCB);10 represents a test point.

[0052] Figure 3: Schematic representation, in an embodiment of the present disclosure, of the generic steps of the method for operating an inspection device to verify the correct alignment of test probes with corresponding test points on a printed circuit board (PCB).

[0053] Figure 4: Illustration of the results obtained from the inspection device, specifically: (a) a correctly aligned test point and test probe; and (b) a misalignment condition where the test point and test probe are not properly aligned, exceeding (or meeting) the admitted tolerance.

[0054] Figure 5: Schematic illustration of a positioning detection configuration of an inspection device according to the disclosure.

[0055] Figure 6: Schematic illustration of a depth measurement configuration of an inspection device according to the disclosure.DETAILED DESCRIPTION

[0056] The present disclosure relates to an inspection device and method for verifying the alignment of an assembly of test probes with corresponding test points on a previously probed printed circuit board (PCB). The device comprises a base for receiving the PCB, a camera for capturing images above the PCB, and a linear motion mechanism enabling camera, or PCB, movement along a two-dimensional X-Y plane. An electronic data processor controls the motion mechanism to move the camera, or the PCB, along a predefined image acquisition path, actuates the camera to capture images of each test point, and outputs the captured images for alignment verification. The device ensures precise alignment of test probes with test points, improving subsequent testing accuracy and reducing errors in PCBs. This device enhances quality control by providing a reliable and automated method for verifying probe alignment, thereby optimizing manufacturing efficiency and reducing defects in PCB testing processes.

[0057] Figure 1 shows in an embodiment according to the present disclosure, an inspection device (1) for verifying the correct alignment of test probes, such as an ICT bed-of-nails. The inspection device is designed to ensure precise positioning and alignment of the test probes through image capturing and processing. Figure 2 depictsa schematic representation of a bed-of-nails test probe assembly (7) probing a PCB (9), in particular on a PCB test point (10), which leaves a minute indentation visible under high magnification.

[0058] In an embodiment, and referring to Figure 1, the inspection device (1) includes a support frame (2), which serves as a main structural element for housing and supporting the components of the inspection device. A base (3) is positioned within the support frame and forms the inspection work area for the PCB during the inspection process. To securely hold the PCB in place, a PCB mounting (4) is fixed to the base structure. In this embodiment, the PCB mounting ensures that the PCB remains stationary during inspection, minimizing misalignment and improving inspection accuracy.

[0059] In an embodiment, to enable controlled movement of a camera (6) for capturing images along a two-dimensional X-Y plane above the PCB fixture, the device is equipped with a linear motion mechanism (5). In an embodiment, this mechanism comprises linear rails, which provides a guided path for motion, at least one motor-driven actuator, which facilitates precise positioning, and a transverse guide, which moves along the X-axis rails and supports the camera (6). The combination of these components allows the image capturing system to move accurately over the PCB, scanning all the test points, ensuring comprehensive test probe alignment verification.

[0060] In a preferred embodiment, the camera (6) captures high-resolution images of the indentation marks on the test points of the PCB, and attached to it the device further comprises an illumination module, which provides optimized lighting conditions for accurate image analysis. The coordinated motion of the vision system ensures that each test point of the PCB under inspection is inspected. The inspection device is configured to accommodate PCBs of various shapes and widths such as of up to 500 mm, thereby ensuring comprehensive coverage. Furthermore, the device is designed to adapt to PCBs composed of different materials and colours, including those with diverse surface treatments.

[0061] In an alternative embodiment, the inspection device (1) features a configuration wherein the camera (6) remains fixed in position above the PCB (9), while the linear motion mechanism (5) is adapted to move the PCB (9) along the two-dimensional X-Y plane beneath the camera. The electronic data processor is configured to control themovement of the PCB (9) to sequentially position each test point (10) within the camera's field of view. As the PCB (9) is moved, the processor actuates the camera (6) to capture images of each test point (10) along the image acquisition path.

[0062] In an embodiment, the linear motion mechanism (5) includes linear rails that define a guided path for motion along the X direction, ensuring stable and accurate positioning. Mounted and movable on these linear rails along a X direction is a transverse guide, which incorporates a (camera or PCB) support that is movable within said transverse guide along the Y direction. To automate and control these movements, the mechanism is equipped with at least one motor-driven actuator. This actuator is responsible for driving the transverse guide along the linear rails in the X direction and for moving the (camera or PCB) support along the Y direction within the transverse guide. This configuration allows for systematic and precise positioning of the camera, or PCB, ensuring optimal inspection coverage and accuracy.

[0063] In a further embodiment, the inspection device (1) includes a second camera positioned below the PCB (9), in addition to the primary camera (6) located above the PCB. The second camera may be fixed in position or configured to move along the two-dimensional X-Y plane, similar to the primary camera (6). When the second camera is movable, an additional linear motion mechanism may be provided to ensure synchronized or independent movement of both cameras, allowing for greater flexibility in image acquisition. This dual-camera configuration enables efficient verification of the alignment of test probes (8) with corresponding test points (10) on both sides of the PCB (9) without requiring repositioning or flipping of the PCB. The captured images from both cameras are then processed and outputted for verification, ensuring precise assessment of the alignment across both PCB surfaces.

[0064] Figure 3 shows a schematic representation of the generic steps of the method for operating an inspection device to verify the correct alignment of test probes with corresponding test points on a printed circuit board. In a prior step, the PCB is subjected to probing using testing probes, such as an ICT bed-of-nails test assembly. During this probing step, the test probes make contact with designated test points (TPs) on the PCB leaving minute indentations on said test points, which serves as a reference for subsequent inspection.

[0065] In an embodiment, and after creating the minute indentations, the PCB (9) is placed onto the PCB mounting (4), which secures it in a fixed position on the base (3) within the support frame (2). This ensures stability during the inspection process.

[0066] Next, the device is calibrated by the operator using at least two test points (10) on the PCB (9). This calibration step establishes a reference framework for the inspection device, allowing the device to accurately map the location of all test points (10) within the Cartesian coordinate system of the physical PCB (9). The calibration ensures that any variations in PCB placement are accounted for before proceeding with the inspection and gives a reference to find the positioning of the other TPs, as a function of the type / size of the given PCB under inspection.

[0067] Following calibration, an electronic data processor receives input data from the calibration step and computes transformation matrices to convert the coordinates of the test points (10) into the reference system used by the inspection device (1). These matrices enable the accurate mapping of each test point (10) for image acquisition.

[0068] The linear motion mechanism (5) then sequentially moves the camera (6) to each test point (10) on the PCB (9). At each test point (10), the camera (6) captures multiple images using different acquisition parameters to enhance contrast and detect the indentation left by the pre-probing step.

[0069] In a further embodiment, the camera (6) captures an image of the full PCB (9) by performing a scanning operation across the surface of the PCB (9).

[0070] The electronic data processor is thereafter configured to output the captured image of each test point for verification of the alignment of the assembly of test probes with the corresponding test points on the PCB.

[0071] In an embodiment, the acquired images are transmitted to the electronic data processor, which executes different sets of image processing algorithms (that are in a later stage compared in order to find the best one), such as the ones relying on traditional feature extraction techniques, from low-pass filtering, adaptive thresholding, edge detection, mathematical morphology, circularity check, to identify: (i) the test point (10) and its centre; and (ii) the indentation left by the corresponding probe from the bed-of-nails test probe assembly (7).

[0072] In an alternative embodiment where the PCB (9) moves while the camera (6) or cameras remain fixed, a similar process occurs. The PCB (9) is mounted on a movable support coupled to the linear motion mechanism (5), ensuring controlled movement along the X-Y plane. The PCB (9) is moved sequentially beneath the fixed camera (6) or cameras, which capture images of each test point (10). If a second camera) is present, it simultaneously captures the opposite face of the PCB (9). The processor analyses the images to verify probe alignment, applying image processing techniques to identify test points (10), their centres, and any indentations from the probing process.

[0073] In an embodiment, the image processing can be performed using artificial intelligence (Al) algorithms, such as deep learning-based object detection and pattern recognition techniques trained on a dataset of previously acquired images of indentation marks of known location and / or depth. These Al-driven approaches enhance the robustness of the analysis by automatically adapting to variations in lighting conditions, surface textures, and PCB layouts, thereby improving accuracy and repeatability. Machine learning models can also be trained to detect anomalies in the indentation patterns, further optimizing the inspection process and reducing false positives or negatives.

[0074] The electronic data processor then calculates a distance (i.e. deviation) between the centre of the test point (10) and the centre of the indentation. If the measured deviation exceeds (or meets) a predefined threshold, said threshold value depending on the characteristics of the given PCB and tolerance requirements, the test point (10) is classified as non-compliant, indicating potential misalignment of the test probes. Said threshold is dependent on the design characteristics of the given PCB and tolerance requirements of the PCB manufacturer.

[0075] Figure 4 illustrates two results outputted from the inspection device, specifically: (a) a correctly aligned test point and test probe; and (b) a misalignment condition where the test point and test probe are not properly aligned, exceeding the admitted tolerance. The tolerances are chosen depending on the manufacturer requirements.

[0076] In an embodiment, the electronic data processor generates a detailed inspection report consolidating the results for all test points (10). The report includes positional deviation measurements, classification of each test point (10) as compliant or non-compliant, and corresponding images of the analysed test points (10). The report provides comprehensive traceability and facilitates corrective actions if necessary.

[0077] The inspection device and method, according to the present embodiment substantially reduce operator time and minimizes subjectivity in evaluating whether the indentation is within tolerance. The generated report is highly detailed, providing deviation values with millesimal precision for each test point (10) across the hundreds of test points on the PCB, ensuring accuracy and repeatability in the inspection process.

[0078] In an embodiment, the electronic data processor is configured to process the captured images using an artificial intelligence model; preferably wherein the artificial intelligence model comprises a deep learning model trained to perform object detection and pattern recognition.

[0079] Figure 5 shows a schematic detailed illustration of a positioning detection configuration of an inspection device, comprising a movable camera (6) positioned above the PCB (9) and two movable illumination emitters (11) arranged laterally with respect to the camera (6). The illumination emitters (11) are oriented to project light onto the inspection region of the PCB (9) at predefined incident angles.

[0080] By analysing variations in reflected light intensity and shadow distribution within the captured image, the system determines the location of the indentation.

[0081] Figure 6 shows a schematic detailed illustration of a depth measurement configuration of an inspection device, comprising a movable camera (6) positioned above the PCB (9). A surface indentation characterized by a depression or puncture produces geometric discontinuities relative to the nominal PCB surface plane. The parameter d represents the depth of the detected feature, i.e., a maximum depth, defined as the vertical distance between a reference upper surface level of the PCB (9) and a lowest point of the deformation.

[0082] By analysing laser or structured light illumination points, the depth d of the indentation is obtained, allowing verification of probe protuberance and alignment with the corresponding test points (TPs) and detection of excessive penetration.

[0083] The term "comprising" whenever used in this document is intended to indicate the presence of stated features, integers, steps, components, but not to preclude thepresence or addition of one or more other features, integers, steps, components or groups thereof.

[0084] The disclosure should not be seen in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof. The above-described embodiments are combinable.

[0085] The following dependent claims further set out particular embodiments of the disclosure.

Claims

C L A I M S1. An inspection device (1) for verifying alignment and / or protuberance of an assembly of test probes (8) in respect of corresponding test points (10) on a PCB (9) previously probed with said assembly of test probes (8), comprising:a base (3) for receiving the PCB (9);a camera (6) for capturing images and / or depth of the PCB from above the PCB; a linear motion mechanism (5) for movement of the camera along a two- dimensional X-Y plane in respect of the PCB (9), or a linear motion mechanism for movement of the PCB (9) along a two-dimensional X-Y plane in respect of the camera; andan electronic data processor configured to:operate the linear motion mechanism (5) to move the camera (6), or the PCB (9), along an acquisition path within the two-dimensional X-Y plane;actuate the camera (6) to capture a plurality of images and / or a plurality of depth measurements, each image and / or depth measurement comprising one or more test points (10) along the acquisition path; andoutput the captured images and / or depth measurements for verification of the alignment and / or protuberance of the assembly of test probes with the corresponding test points on the PCB.

2. The inspection device according to the previous claim, wherein the electronic data processor is further configured to process a captured image and / or depth measurement of each test point to be verified for recognition of an indentation mark left by a test probe on said each test point.

3. The inspection device according to the previous claim, wherein the electronic data processor is further configured to process the captured image and / or depth measurement of each test point to be verified for recognition of a location of the indentation mark.

4. The inspection device according to the previous claim, wherein the electronic data processor is configured to calculate a distance between a centre of each test point and the location of the indentation mark on said each test point.

5. The inspection device according to the previous claim, wherein the electronic data processor is further configured to compare the distance between a centre of each test point and the location of the indentation mark with a predetermined distance threshold.

6. The inspection device according to any of the previous claims, wherein the electronic data processor is further configured to apply a machine-learning model to the outputted captured images and / or depth measurements for recognising the indentation mark left by a test probe on said each test point.

7. The inspection device according to the previous claim, wherein the test point is classified as non-compliant if the distance meets or exceeds the predefined threshold; and compliant if the deviation is below the threshold.

8. The inspection device according to claim 2 or according to claim 2 and any of the claims 3-7, wherein the electronic data processor is further configured to process depth measurements of said each test point for recognition of a maximum depth of the indentation mark.

9. The inspection device according to the previous claim, wherein the electronic data processor is further configured to compare a measured maximum depth of an indentation mark of said each test point with a predetermined depth threshold, in particular configured to compare the maximum depth of an indentation mark of said each test point against a predetermined depth threshold range.

10. The inspection device according to any of the previous claims, wherein the camera (6) is an optical camera, in particular a camera comprising a telecentric lens.

11. The inspection device according to any of the previous claims, wherein the camera is a 3D camera, in particular a laser camera configured to provide a 3D-point cloud.

12. The inspection device according to any of the previous claims, wherein the electronic data processor is further configured for simultaneous or sequential verification of alignment and protuberance of the assembly of test probes.

13. The inspection device according to any of the previous claims, further comprising a user interface for receiving manual user input, in particular for receiving an alignment and / or depth threshold.

14. The inspection device according to any of the previous claims 5-13, further comprising a display; wherein the electronic data processor is configured to present in said display to a user, a calculated distance and / or depth of the indentation mark for each test point.

15. The inspection device according to the previous claim, wherein the electronic data processor is further configured to generate a graphical overlay on each captured image, said graphical overlay visually indicating the calculated distance and / or depth for each test point.

16. The inspection device according to any of the previous claims 5-15, wherein the electronic data processor is further configured to generate a report comprising a calculated distance and / or depth of the indentation mark for each test point; preferably comprising an indication of whether the calculated distance exceeds a predetermined distance threshold and / or an indication of whether the depth exceeds a predetermined depth threshold.

17. The inspection device according to any of the previous claims, wherein said base is positioned within a support frame (2).

18. The inspection device according to the previous claim, further comprising a PCB mounting (4) for holding the PCB in place; wherein the PCB mounting is fixed to the base.

19. The inspection device according to any of the previous claims, further comprising an illumination module attached to the camera (6) and configured for moving with the camera for enhancing quality of the image captured.

20. The inspection device according to the previous claim wherein the illumination module is an adjustable light source configured to adapt its intensity based on ambient lighting conditions.

21. The inspection device according to any of the previous claims, further comprising a PCB feeding system for automatic positioning of the PCB (9) within the base (3) for inspection.

22. The inspection device according to any of the previous claims, further comprising a second camera positioned opposite to the first camera in respect of the PCB (9), wherein the electronic data processor is configured to actuate simultaneously the two cameras to capture images of two opposite faces of the PCB (9) during inspection.

23. The inspection device according to any of the previous claims, wherein the camera (6) is positioned above the PCB (9) and is configured to capture a single image covering an entire PCB (9) upper surface for inspection.

24. The inspection device according to claim 22 or 23, wherein the second camera is positioned below the PCB (9) and is configured to capture a single image covering an entire PCB (9) lower surface for inspection.

25. The inspection device according to any of the previous claims, wherein the linear motion mechanism (5) comprises:linear rails for providing a guided path for linear motion along a X direction;a transverse guide mounted on the linear rails and comprising a support movable along a Y direction within said transverse guide;at least one motor-driven actuator for movement of the transverse guide along the linear rails and for moving the camera along a Y direction within said transverse guide.

26. The inspection device according to the previous claim, wherein the camera is mounted onto the support.

27. The inspection device according to claim 25, wherein the PCB is mounted onto the support.

28. The inspection device according to any of the previous claims, wherein the assembly of test probes is an ICT bed-of-nails test probe assembly.

29. A method for verifying alignment and / or protuberance of an assembly test probes in respect of corresponding test points (10) on a PCB (9) previously probed with said assembly of test probes, comprising:providing an inspection device (1) according to any of the preceding claims; operating the linear motion mechanism (5) to move the camera (6), or the PCB (9), along an acquisition path within the two-dimensional X-Y plane; actuate the camera (6) to capture an image and / or depth measurement comprising one or more test points (10) along the acquisition path; and output the captured images and / or depth measurements for verification of the alignment and / or protuberance of the assembly of test probes with the corresponding test points on the PCB.

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