Determining position of tool in working area of adhesion tester

Abstract

A system for determining a tool-to-camera distance in a working area of an adhesion tester, comprising:-a light source positioned on a side of the working area, configured to emit a light beam to illuminate the tool from the side; -a camera positioned laterally of the work area opposite the light source, configured to take an image of the light source and the tool; -a processor communicatively coupled with the camera and configured for processing images received from the camera, where, in use, the tool is positioned within a light beam emitted from the light source to the camera, and where the tool is positioned within the light beam emitted from the light source to the camera; the processor is configured to determine positioning data of the tool by evaluating a local difference in light intensity on an image taken by the camera while viewing the light source and the tool.

Description

Technical Field

[0001] The present invention relates to a system and method for determining the position of a tool in a working area of ​​a bond tester. Background Art

[0002] A bond tester is a device used to test the properties (e.g. bond strength) of components such as contacts mounted to a substrate (usually a printed circuit board). As the components to be tested, as well as the tools used, become smaller, it becomes increasingly important to determine the position of the tool with high precision. Whereas previously an accuracy in the sub-millimeter range was considered sufficient, today a bond tester operator may require an accuracy of less than 1nm.

[0003] Current systems for determining the relative position of a tool rely on a camera mounted above the working area of ​​the tool, the tool itself, a fiducial, an operator, and a microscope. In current systems, the distance between the camera and the tool is (assumed) fixed. The camera mounted above the working area of ​​the tool looks straight down and can be moved to a position above the fiducial. The processor stores the relative position of the camera. Next, the tool is moved to a position above the fiducial. This is done by the operator, who uses a microscope to observe the tool / fiducial / working area and moves the tool until it is precisely above the fiducial. The operator provides input that the tool is above the fiducial, and the relative position of the tool is also stored by the processor. The distance between the camera and the tool can be obtained by comparing the relative position of the tool when it is above the fiducial with the relative position of the camera when it is above the fiducial. When using a bond tester, each time a test is performed, the camera is first positioned above the object to be tested (automatically), and then the tool is moved according to the tool to camera distance so that the tool is above the object to be tested. The process of determining the tool to camera distance can be called "calibration" of the bond tester.

[0004] There are some disadvantages to this current system. While the tool-to-camera distance is assumed to be constant / fixed, this is not actually the case. When the base to which both the tool and camera are mounted is heated, this can change the tool-to-camera distance by a micron or a few microns. Also, when another tool is put in place, the position of that tool may be slightly different from the original tool, requiring recalibration to determine the tool-to-camera distance again. Also, the current system is relatively slow because the operator must calibrate while viewing the system through a microscope, and the calibration can be imprecise / requires an experienced operator. Summary of the invention

[0005] The object of the present invention is to ameliorate at least one of these disadvantages.

[0006] Therefore, a first aspect of the present invention relates to a system for determining the position of a tool in a working area of ​​a bond tester, the system comprising:

[0007] - a first light source, which is positioned to the side of the working area and is configured to emit a light beam for illuminating the tool from the side;

[0008] - a side camera positioned on the side of the working area opposite the first light source, the side camera being configured to directly or indirectly capture an image of the light beam and the tool;

[0009] a processor communicatively coupled to the side cameras and configured to process images received from the side cameras,

[0010] wherein, in use, the tool is positioned within a beam emitted by the first light source to the side camera, and

[0011] Therein, the processor is configured to determine positioning data of the tool by evaluating local differences in light intensity on an image captured by the side camera when observing the light beam and the tool.

[0012] According to a first aspect of the invention, cameras and light sources are placed on both sides of the working area, the camera effectively observing the light source and the light source effectively emitting a light beam towards the camera. In particular, the camera can be directly positioned in the optical path of the light emitted by the light source, or a mirror can ensure that the camera is effectively positioned in the optical path of the light emitted by the light source. The tool is also positioned in the optical path, and the tool is effectively configured between the light source and the camera. Therefore, a portion of the light emitted by the light source is blocked by the presence of the tool, so that the camera sees a "shadow" at the location of the tool. From the image obtained by the camera, by searching for the shadow, the processor can determine the position of the tool, for example, the position in an absolute reference or relative to another object. Therefore, compared with currently known systems, the position of the tool can now be automatically determined without the operator observing the tool via a microscope and manually moving the tool. This allows position determination to be performed not only faster, but also more accurately.

[0013] In an embodiment, the system comprises a second light source, which is positioned to the side of the working area and is configured to emit a light beam for illuminating the tool from the side, wherein one of the first light source and the second light source is configured substantially along the transverse direction of the working area, and wherein the other of the first light source and the second light source is configured substantially along the longitudinal direction of the working area. In particular, the two light sources can be configured at a 90 degree angle relative to each other. When a single camera can only determine the position of the tool in one dimension, the use of two cameras enables the system to determine the position of the tool in two dimensions, especially when the mutual positions of the cameras are judiciously chosen - such as the mentioned 90 degree angle relative to each other. As will be explained below, when a mirror is used to manipulate the path of the light beam emitted by the light source, the tool can be observed twice in one camera image - so only a single camera is needed to determine the position of the tool in two dimensions. However, alternatively, the system may include two cameras, one associated with each light source, wherein preferably each camera determines the position of the tool in one dimension.

[0014] In an embodiment, the system further comprises at least one mirror configured to reflect light beams emitted by one or more light sources toward the side camera. As will be explained in more detail below, when the mirrors are used effectively, light emitted by two light sources can be captured with a single camera - making the system simpler and cheaper.

[0015] In an embodiment, the field of view of the side camera is configured at an angle relative to both the longitudinal and transverse directions of the working area, and the light beams emitted by the first light source and the second light source are indirectly emitted to the side camera. In this embodiment, substantially the same object distance for the two captured images can be achieved, so that both images are clear and can be processed with higher accuracy; resulting in a more accurate determination of the tool position.

[0016] In an alternative embodiment, the side cameras are arranged substantially in the transverse direction or in the longitudinal direction of the working area, the light beam emitted by one of the light sources is sent directly to the side camera, and the light beam emitted by another of the light sources is sent indirectly to the side camera. Direct observation of at least one light source has the advantage that the image is not obstructed by mirror defects and / or mirror deviations.

[0017] In an embodiment, the optical path length from the first light source to the side camera is substantially equal to the optical path length from the second light source to the side camera. As described above, this will result in the clearest image and the most accurate position determination.

[0018] In an embodiment, the system further comprises a beam splitter positioned in the optical path of at least one of the light sources, the beam splitter being configured to selectively project light of one of the two light sources, for example in an alternating manner, onto the side camera. In particular, it is advantageous to provide a beam splitter when the system comprises two light sources and relies on a single camera to capture the light of the two light sources. The beam splitter can ensure that the images do not overlap, resulting in optimal results in terms of image clarity and tool detection accuracy.

[0019] In an embodiment, the side camera is configured as a reference side camera, preferably an automatic reference side camera. The reference camera can directly calculate the absolute position of the tool, so there is no need to determine the relative position with respect to another element that may not be in the field of view.

[0020] In an embodiment, the side camera includes a telecentric lens. Such a lens is best suited to capture the shadow of the tool with minimal distortion, resulting in the clearest view and most accurate position determination, regardless of the distance between the lens and the tool / the distance between the lens and the light source.

[0021] In an embodiment, the light source is associated with a collimator so that a collimated light beam is emitted from the light source. For this particular application, the collimated light beam will result in minimal distortion so that the shadow of the tool can be best captured.

[0022] It is particularly advantageous to use both a collimator that emits a collimated light beam and a telecentric lens in front of the camera to capture the collimated light beam. This results in the clearest view of the light-blocking tool in one part of the image.

[0023] In an embodiment, the light source emits light of a single wavelength, for example having a wavelength between 575nm and 585nm. When emitting light of a single wavelength, the extent to which the light beam is refracted by the tool will be minimized. When the light and tool are photographed using a CCD camera, light with this particular wavelength results in the clearest image, although other wavelengths may also work well.

[0024] In an embodiment, the processor is further configured to obtain tool dimensional data by evaluating local differences in light intensity on an image captured by at least one side camera when viewing the light source and the tool. In particular, the processor can determine the width of the tool and / or the tip shape of the tool based on the dimensional data of the tool. This functionality allows the system to verify that the correct tool is selected for the selected task and / or to monitor tool wear over time and / or to evaluate and correct the concentricity of the tool.

[0025] In an embodiment, the system further comprises a top camera associated with the tool, the top camera taking images from the work area from above and being communicatively coupled to the processor, the processor also being configured to determine the relative position of the tool with respect to the top camera based on images of the fiducials taken by the top camera and images of the fiducials and the tool taken by the side cameras. When the top camera is implemented in addition to the side cameras, not only the position of the tool can be determined, but also the tool-to-(top) camera distance can be determined - but more accurately than before, so that when operating the adhesion tester, the tool-to-top camera distance can be used again for quick testing, and the position of the tool does not need to be determined before each test cycle. Thus, calibration using the side cameras and the top camera can be performed once or several times a day and / or each time a different tool is selected, depending on the tool-to-top camera distance when operating the adhesion tester.

[0026] A second aspect of the invention relates to an adhesion tester comprising the above system. It is worth noting that the technical advantages that can be obtained with this adhesion tester are the same as those that can be obtained with the system described as the first aspect of the invention.

[0027] A third aspect of the present invention relates to a method for determining the position of a tool of an adhesion tester, wherein, using an adhesion tester comprising the tool, the method comprises the following steps:

[0028] - Position the tool above the work area;

[0029] - illuminating the tool using a light source arranged on the side of the working area;

[0030] - capturing the image with a side camera that directly or indirectly views the light source and the tool, and the side camera is positioned to the side of the work area opposite the light source so that the tool is placed in an emitted beam of light traveling from the light source toward the camera;

[0031] - Processing the images obtained with the camera by evaluating local differences in light intensity over the captured images in order to obtain positioning data for the tool.

[0032] It is noteworthy that the technical advantages that can be obtained using this method are the same as the technical advantages that can be obtained using the system described as the first aspect of the present invention and the adhesion tester described as the second aspect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] These and other aspects of the present invention will now be elucidated with reference to the accompanying drawings, in which similar or identical elements are indicated by the same reference numerals. In these drawings:

[0034] Figure 1schematically shows an isometric view of a currently known bond tester including a tool, a tool working area and a camera;

[0035] Figure 2A Schematically shows a top view of a first embodiment of a system for determining the position of a tool in a working area of ​​an adhesion tester according to the invention;

[0036] Figure 2B Schematic diagram showing the use of Figure 2A images available to the system;

[0037] Figure 3 Schematically shows a top view of a second embodiment of the system for determining the position of a tool in a working area of ​​an adhesion tester according to the invention;

[0038] Figure 4A Schematically shows a top view of a third embodiment of a system for determining the position of a tool in a working area of ​​an adhesion tester according to the present invention;

[0039] Figure 4B Schematically shows Figure 4A a more detailed view of the system shown;

[0040] Figure 5A Schematically shows the Figure 3 A top view of a system, wherein a reference part is present in the working area;

[0041] Figure 5B schematically showing an isometric view of the work area, reference pieces and tools; and

[0042] Figure 5C Schematically shows the use of Figure 5A Images obtained with the system setup shown. DETAILED DESCRIPTION

[0043] Figure 1A portion of a currently known bond tester is shown. A set of tools 200 is shown, with one tool pointing downwardly toward a tool working area 300. By rotating the tool 200 about an axis generally pointing inward or outward from the paper, a different tool 200 can be selected for testing purposes. Also shown on the tool working area 300 is a reference piece 400, which is used for calibration purposes as described below. The bond tester also includes a top camera 7. The top camera and the set of tools 200 are mounted on the same base; when one moves, the other moves as well. When the top camera 7 looks down, it can see what is directly below it, but not the tool. Therefore, when a person is testing an object to be tested in the working area 300 with a tool 200, they are actually working in a blind area, i.e., without a direct line of sight. Therefore, it is critical to accurately calibrate the bond tester. Today, calibration of a bond tester is usually performed in the following manner. First, the top camera 7 is moved until it is above the reference piece 400. By analyzing the image captured by the top camera 7, it can be determined when the top camera 7 is above the reference piece 400. Then, the top camera 7 and a set of tools 200 are moved until the tool 200 is located above the reference piece 400. By observing the working area 300 with a microscope, it can be determined when the tool 200 is located above the reference piece 400. The movement distance (in both the lateral and longitudinal directions) when the tool 200 is moved above the reference piece is tracked, and the tool-to-camera distance can be obtained from the movement distance. The above process is called calibrating the adhesion tester, thereby obtaining the tool-to-camera distance. Each time a test is to be performed, the top camera 7 is first positioned above the object to be tested, and then the top camera 7 and the tool set 200 are moved according to the tool-to-camera distance, assuming that the tool 200 is located above the object to be tested after the movement. Preferably, calibration is performed at least each time (and every day) a different tool 200 is selected. The disadvantage of this calibration method is that it is relatively slow and relies on human operators who may make mistakes and / or require training and experience.

[0044] Now turn to Figure 2A , shows a novel system 100 in a top view, which allows obtaining the absolute position of a tool 200 in a working area 300. It should be noted that for the purpose of determining the relative position of the tool 200 with respect to the top camera 7, the effective working area 300 may be much smaller than the working area in which the tool can operate. In an embodiment, the effective working area 300 for determining the relative position of the tool 200 with respect to the top camera overlaps with the tool working area. The system 100 relies on a light source 1, a camera 2 and a processor 3. Figure 1Compared to the prior art bonding tester described, the camera 1 of the new system 100 is placed on the side of the working area 300 and illuminates the tool 200 from the side by emitting a light beam 11 during use. The side camera 2 is also placed on the side of the working area 300 opposite the light source 1 and observes the tool 200 and the light source 1 so as to capture the light emitted by the light source 1. Therefore, when observing the light path of the light beam 11 from the light source 1 to the camera 2, the tool 200 is located within the light beam 11. Preferably, the light source 1 can be associated with a collimator 12 so that the light source 1 emits a collimated light beam. Further preferably, the camera includes a telecentric lens 21 and operates as an automatic reference camera. In particular, in this arrangement, when the camera 2 observes the tool 200 and the light source 1, the tool 200 will block the light beam 11 emitted by the light source 1, so that the image captured by the camera 2 has a different light intensity depending on the position of the tool 200. Figure 2B 2 shows a view of a camera image obtained in this way, in which the edge 201 of the tool 200 is clearly visible, so that the position of the tool 200 can be automatically determined by a processor associated with the camera 2. Figure 2A In the arrangement shown, the camera 2 directly views the tool 200, the work area 300 and the light source 1 without any intermediate mirrors or the like.

[0045] from Figure 2B As can be seen, images obtained in this way can be so clear and accurate that tool dimensional data can even be determined by evaluating local differences in light intensity – opening the door to predictive tool maintenance procedures and checking the correctness of tool selection.

[0046] although Figure 2A The schematic arrangement shown in allows the position of the tool 200 to be determined in one direction (i.e., longitudinally) and the tool 200 to be oriented in said direction, but it may be necessary to add a second light source to the system 100 in order to also determine the position of the tool 200 in another direction (i.e., transversely). Although the simplest solution may be to add another light source and another camera (e.g., in said other direction) Figure 2A ), thereby forming a system with two light sources and two cameras, but such a system may become relatively expensive and lead to further calibration problems between the two cameras.

[0047] Using one or more mirrors, light emitted by the first and second light sources may be projected onto the lens of a single camera. Figure 3 and Figure 4A Two such systems 100 are shown.

[0048] exist Figure 3 In the system 100 shown, Figure 2ACompared to the arrangement of , a second light source 4 is added, and a collimator 42 associated therewith is also added. Compared to the first light source 1 arranged along the longitudinal direction of the working area 300, the second light source 4 is arranged in a vertical orientation, so that the second light source 4 is arranged along the transverse direction of the working area 300. Therefore, the second light source 4 is also located on the side of the working area 300 and illuminates the tool 200. As shown in more detail, the light emitted by the second light source 4 is reflected by the mirror and the beam splitter 6 and projected into the lens of the camera 2, while the light emitted by the first light source 1 can pass through the beam splitter 6. In the present embodiment, for this purpose, the beam splitter 6 is arranged at a 45 degree angle relative to the horizontal / lateral direction. However, those skilled in the art will understand that other configurations are also entirely possible, especially when more than one mirror is used. In this way, the camera 2 directly receives the light emitted by the first light source 1 and indirectly receives the light emitted by the second light source 4.

[0049] Figure 3 A and Figure 3 A small disadvantage of the arrangement shown in B is that the optical path from the first light source 1 to the camera 2 may be shorter than the optical path from the second camera 4 to the camera 2. This may result in an unclear image of the tool 200 on the image captured by the camera 2. In addition, the positioning of the light sources 1, 4 and the camera 2 may be relatively challenging because Figure 3 The system 100 shown should position the beam splitter 6 behind the tool 200 relative to the second light source 4 and in front of the tool 200 relative to the first light source 1. This results in a smaller useful working area. To address these relative disadvantages, a beam splitter 6 can be used such as Figure 4A and Figure 4B System 100 is shown.

[0050] As shown in the figure, Figure 4A The system 100 comprises two light sources 1, 4, each illuminating a tool 200 in a work area 300 from one side. Each light source 1, 4 is associated with a collimator 12, 42, respectively, so that they emit collimated light 11, 41. The system 100 also comprises a single camera 2, which is arranged at the side of the work area 300 and is generally opposite to the first light source 1 and the second light source 4. The camera 2 is arranged at an angle α relative to the longitudinal axis X of the work area 300.

[0051] The left side of the figure shows an incident light beam 11 emitted by a first light source 1. The light beam 11 illuminates the tool 200 and is reflected by the first mirror 5. In the example shown here, the first mirror 5 is configured at an angle β with respect to the transverse direction, the magnitude of the angle β being 50 degrees. Since the angle of incidence is equal to the angle of incidence, the light beam 11 leaves the first mirror 5 with an orientation of 10 degrees with respect to the transverse direction Y. Subsequently, the light beam 11 is reflected by the beam splitter 6, which in the example embodiment shown is configured to have an angle γ with an orientation of 45 degrees with respect to the transverse direction Y. This ensures that the light beam 11 leaves the beam splitter 6 with an orientation of 10 degrees with respect to the longitudinal direction X. In the embodiment shown, the field of view of the camera 2 is also oriented at 10 degrees with respect to the longitudinal direction, so that the light beam 11 is received by the lens of the camera 2 as if the camera 2 were looking directly at the light source 1 (e.g. Figure 2A shown).

[0052] Following the path of the second light beam 41 (which enters at the bottom of the figure), the second light beam 41 first illuminates the tool 200 and is reflected by the second mirror 8. In the example shown here, the second mirror 8 is configured at an angle δ with respect to the transverse direction, the magnitude of which is 40 degrees. Since the angle of incidence is equal to the angle of exit, the second light beam 41 leaves the second mirror 8 at an orientation of 10 degrees with respect to the horizontal direction X - the same orientation as the first light beam 11 after being reflected by both the mirror 5 and the beam splitter 6. The second light beam 41 then encounters the beam splitter 6, which allows the light beam to pass through it without affecting its characteristics. This also ensures that the second light beam 41 leaves the beam splitter 6 at an orientation of 10 degrees with respect to the longitudinal direction X and enters the camera 2.

[0053] With the arrangement shown in the figure, the light beams 11, 41 may overlap. However, various beam splitters 6 may be used, so that, for example, only half of the light beams 11, 41 may be allowed to pass / reflected by the beam splitter 6, so that half of the camera lens 21 sees the image of one light source, while the other half of the camera lens sees the image of the other light source. Alternatively, the light source may be turned on and off alternately, so that the images of the two light sources are received alternately.

[0054] Understandably, using Figure 4A and Figure 4B In the arrangement shown, the optical paths of the light beams 11 , 41 from the first light source 1 to the camera 2 and from the second light source 4 to the camera 2 are substantially of equal length.

[0055] Although the above-described embodiments have a specific arrangement, in general, it is desirable that when the light beam 11 emitted by the first light source 1 and the light beam 41 emitted by the second light source 4 both project onto the lens of the camera 2 at the same angle, the lens of the camera 2 is configured perpendicular to the angle so that it is as if the camera 2 is looking directly at the light sources 1, 4. In general, this can be achieved by using an arrangement as shown above, wherein one of the mirrors 5, 8 is located at the opposite end of the working area compared to where the light beams 11, 41 are incident, the desired mounting angle α of the camera 2 is determined, and the first mirror 5 is mounted at an angle of 45 degrees - 1 / 2α, the second mirrors 5, 8 are mounted at an angle of 45 degrees + 1 / 2α, and the beam splitter 6 is mounted at a position in the optical path after the light beams 11, 41 have been reflected by the first mirror 5 and the second mirror 8 oriented at 45 degrees. However, as Figure 3 As disclosed in the embodiment shown in FIG. 4A , other arrangements are also conceivable that can lead to the same desired effect of using a single camera 2 , two light sources 1 , 4 and reflecting the light beams 11 , 41 emitted by the light sources 1 , 4 into the camera 2 .

[0056] Figure 2 Figure 3 The system 100 shown in FIG. 4 allows the position of the tool 200 to be directly and automatically obtained. Since the position of the object to be tested by the tool on the work area 300 is not always known, the tool-to-camera distance may still have to be determined - it should be noted that the tool-to-camera distance still refers to the distance between the top camera of the bond tester and the tool of the bond tester, rather than the distance between the side camera of the system described herein and the tool. In order to obtain this tool-to-camera distance using the system disclosed herein, it may be necessary to position the tool, the side camera, and the top camera near the reference piece 400 on the work area 300 - see Figure 5A , Figure 5B and Figure 5C It is worth noting that in Figure 5A In the example, the two light sources 1, 4 and the camera 2 are constructed in the same way as Figure 3 A and Figure 3 B, but now the reference element 400 is visible in the working area 300 instead of the tool 200. Since the system is shown in a top view, for example Figure 1The top camera shown in is not visible here. To obtain the tool-to-camera distance, the top camera is positioned above the center position of the reference piece 400. With the top camera positioned above the reference piece 400, the coordinates of the tool 200 can be obtained and stored by the processor 3 associated with the side camera 2. In a second step (which can optionally be performed as the first step), the tool 200 is positioned above or near the reference piece 400, in which position the coordinates of the tool 200 are again obtained and stored by the side camera 2. From these two measurements, the tool-to-camera distance can be obtained, possibly after accounting for the misalignment of the tool 200 above the reference piece 400 by obtaining the position and distance between the edge 401 of the reference piece 400 and the edge 201 of the tool 200. Advantageously, in the second step, the person has visual evidence that the tool 200 is indeed located directly above the reference piece 400. Advantageously, when image recognition technology is used, the above technology allows the person to calculate the tool-to-camera distance without the involvement of an operator.

[0057] Reference numerals list

[0058] 1. The First Light Source

[0059] 11 Beam

[0060] 12 Collimator

[0061] 2 Side cameras

[0062] 21 Telecentric lens

[0063] 3 Processor

[0064] 4 Second light source

[0065] 41 Beam

[0066] 42 Collimator

[0067] 5. Mirror

[0068] 6 Beam splitter

[0069] 7 Top Camera

[0070] 8 Mirror

[0071] 100 Systems

[0072] 200 Tools

[0073] 201 Tool Edge

[0074] 300 working area

[0075] 400 reference parts

[0076] 401 Reference part edge

[0077] α is the angle of the side camera's field of view relative to the longitudinal direction

[0078] β is the angle between the first mirror and the lateral direction

[0079] γ Angle between the directional beam splitter and the transverse direction

[0080] δ is the angle between the second mirror and the lateral direction

Claims

1. A system (100) for determining the position of a tool (200) in a working area (300) of an adhesion tester, the system (100) comprising: - a first light source (1) positioned to the side of the working area (300) and configured to emit a light beam (11) for illuminating the tool (200) from the side; - a side camera (2) positioned on the side of the working area (300) opposite the first light source (1), the side camera (2) being configured to directly or indirectly capture an image of the light beam (11) and the tool (200); - a processor (3) communicatively coupled to the side camera (2) and configured to process images received from the side camera (2), wherein, when in use, the tool (200) is positioned within the light beam (11) emitted by the first light source (1) to the side camera (2), and The processor (3) is configured to determine positioning data of the tool (200) by evaluating local differences in light intensity on an image captured by the side camera (2) when observing the light beam (11) and the tool (200).

2. The system according to claim 1, in, The system (100) comprises a second light source (4) positioned to the side of the working area (300) and configured to emit a light beam (41) for illuminating the tool (200) from the side, wherein one of the first light source (1) and the second light source (4) is substantially arranged along a transverse direction (X) of the working area (300), and wherein the other of the first light source (1) and the second light source (4) is substantially arranged along a longitudinal direction (Y) of the working area (300).

3. The system according to claim 2, further comprising at least one mirror (5, 8) configured to reflect the light beam (11, 41) emitted by the light source (1, 4) towards the side camera (2).

4. The system according to claim 3, wherein: The field of view of the side camera (2) is configured at an angle (α) relative to both the longitudinal direction (Y) and the transverse direction (X) of the working area (300), and the light beams (11, 41) emitted by the first light source (1) and the second light source (4) are indirectly emitted to the side camera (2).

5. The system according to claim 3, wherein: The side camera (2) is basically arranged in the transverse direction (X) or the longitudinal direction (Y) of the working area (300), the light beam (11, 14) emitted by one of the light sources (1, 4) is directly sent to the side camera (2), and the light beam (11, 14) emitted by the other of the light sources (1, 4) is indirectly sent to the side camera (2).

6. A system according to any one of claims 2 to 5, wherein: The optical path length from the first light source (1) to the side camera (2) is substantially equal to the optical path length from the second light source (4) to the side camera (2).

7. A system according to any one of the preceding claims 2 to 6, wherein: The system (100) also includes a beam splitter (6), which is positioned in the optical path of at least one of the light sources (1, 4), and the beam splitter (6) is configured to selectively project the light beam (11, 41) of one of the two light sources (1, 4) onto the side camera (2), for example in an alternating manner.

8. A system according to any one of the preceding claims, wherein: The side camera (2) is designed as a reference side camera, preferably an automatic reference side camera.

9. A system according to any one of the preceding claims, wherein: The side camera (2) comprises a telecentric lens (21).

10. A system according to any one of the preceding claims, wherein: The light source (1, 4) is associated with a collimator (12, 42) such that a collimated light beam (11, 41) is emitted from the light source (1, 4).

11. A system according to any one of the preceding claims, wherein: The light source (1, 4) emits a light beam (11, 41) having a single wavelength, for example a wavelength between 575 nm and 585 nm.

12. A system according to any one of the preceding claims, wherein: The processor (3) is also configured to obtain tool (200) size data by evaluating local differences in light intensity on an image captured by at least one side camera (2) when observing the light beam (11, 41) and the tool (200).

13. The system of any of the preceding claims, further comprising a top camera (7) associated with the tool (200), the top camera (7) capturing images from the work area (300) from above and communicatively coupled to the processor (3), the processor (3) being further configured to determine a relative position of the tool (200) relative to the top camera (7) based on: - an image of the reference point (400) captured by the top camera (7); and - The image of the reference point (400) and the tool (200) captured by the side camera (2).

14. An adhesion tester comprising a system (100) according to any one of the preceding claims.

15. A method for determining the position of a tool (200) of an adhesion tester, wherein: Using an adhesion tester comprising the tool (200), the method comprises the following steps: - positioning the tool (200) above its working area (300); - illuminating the tool (200) by emitting a light beam (11, 41) towards the tool (200) using a light source (1, 4) arranged at the side of the working area (300); - taking an image with a side camera (2), the side camera (2) directly or indirectly viewing the light beam (11, 41) and the tool (200), and the side camera (2) being positioned on the side of the working area (300) opposite the light source (1, 4), so that the tool (200) is placed in the light beam (11, 14) emitted by the light source (1, 4) to the side camera (2); - Processing the images obtained with the side camera (2) to obtain positioning data of the tool (200) by evaluating local differences in light intensity on the captured images.

Images