An automatic focusing system, method, and 3D printing equipment for 3D printing.

Abstract

An automatic focusing system and printing method for 3D printing equipment are disclosed. The system includes a laser, a collimator, a beam splitter, a galvanometer system, a first focusing module, a second focusing module, a photodetector, and a control system. The laser emitted by the laser sequentially enters the collimator and the beam splitter, and after transmission through the beam splitter, it enters the galvanometer system and the second focusing module. After deflection by the galvanometer system and focusing by the second focusing module, the laser light enters a working plane that reflects the laser. The reflected light from the working plane returns to the beam splitter after deflection by the galvanometer system and focusing by the second focusing module. Reflected by the beam splitter, the light enters the first focusing module for focusing. The photodetector collects the laser output from the first focusing module and converts it into an electrical signal. This invention can more accurately detect the light spot on the actual working surface, offering advantages such as high precision, online operation, and real-time capability in determining the focusing position of the light spot.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, and in particular to an automatic focusing system, method and 3D printing equipment for 3D printing. Background Technology

[0002] Additive manufacturing is a rapid manufacturing technology that uses a laser to scan and stack layers to form a three-dimensional object. The process is as follows: First, the three-dimensional model of the workpiece is sliced ​​to obtain the cross-sectional information of each layer. Powdered material is then evenly spread onto the surface of the work platform, and the laser selectively melts the powder according to system instructions. After one cross-section is completed, a new layer of material is added, and the process continues to selectively scan based on the cross-sectional information corresponding to the three-dimensional object. This method is repeated for the next cross-section, ultimately resulting in the three-dimensional object.

[0003] In the aforementioned technologies, focal plane calibration of the laser beam is a fundamental step in the application of industrial additive manufacturing. Ensuring that the laser's working plane aligns with the designated printing plane, or adjusting the laser's working plane to a predetermined position, is essential for guaranteeing print quality. Current focal plane calibration methods involve adjusting the substrate to the target working height and placing a beam measuring device with a reflector on the substrate to redirect the laser beam to the beam measuring instrument for measurement of the beam's state (including beam size and shape). The beam measuring instrument works by using slit scanning to filter the beam and then using a photodetector of the appropriate wavelength for photoelectric conversion to acquire beam data. However, this method relies solely on the substrate as a reference, and the placement of the beam measuring device can easily introduce height errors, meaning the focused plane cannot be guaranteed to coincide with the actual working plane. Furthermore, beam measuring instruments are expensive and have high after-sales costs. Summary of the Invention

[0004] To address the aforementioned problems in existing technologies, this invention provides an automatic focusing system, method, and 3D printing equipment. In this automatic focusing system, method, and 3D printing equipment, the photodetector used for detection does not need to be placed on the working plane, allowing for flexible placement and avoiding excessive manual operation on the working plane. Laser focus adjustment is also convenient. Furthermore, because the adjustment position is not limited by the working cavity space, this invention easily achieves focus detection at any position across the entire surface and reduces errors caused by the placement of the detection equipment. It can more accurately detect the light spot condition on the actual working surface, offering advantages such as high precision, online operation, and real-time capability in determining the light spot focus position.

[0005] To achieve the above objectives, the present invention provides an automatic focusing system for 3D printing equipment, comprising a laser, a collimator, a beam splitter, a galvanometer system, a first focusing module, a second focusing module, a photodetector, and a control system. The laser emitted by the laser sequentially enters the collimator and the beam splitter, and after transmission through the beam splitter, enters the galvanometer system and the second focusing module. After deflection by the galvanometer system and focusing by the second focusing module, the laser light enters a working plane that has a reflective function. This ensures that the reflected light, at least from the working plane, returns to the beam splitter after deflection by the galvanometer system and focusing by the second focusing module. The reflected light then enters the first focusing module and is focused. The photodetector collects the laser light output from the first focusing module and converts it into an electrical signal.

[0006] The control system receives electrical signal data from the photodetector in real time and automatically adjusts the position of the collimator and / or the height of the working plane to cause variations in the strength of the received electrical signal data. Adjustment stops when the received electrical signal is at its strongest, completing automatic focusing. The first focusing module of this application should have focusing or imaging capabilities so that the working plane and the photodetector receiving surface become each other's image; for example, it can be a separate focusing lens or a lens group.

[0007] As a further preferred embodiment of the present invention, the automatic focusing system of the 3D printing equipment further includes a drive system for adjusting the position of the collimator and adjusting the height of the working plane.

[0008] As a further preferred embodiment of the present invention, the automatic focusing system of the 3D printing equipment further includes a quarter-wave plate, which is disposed between the beam splitter and the galvanometer system, or between the beam splitter and the second focusing module, for changing the polarization state of the reflected light.

[0009] As a further preferred embodiment of the present invention, the laser emits laser power of 1-30W.

[0010] As a further preferred embodiment of the present invention, the second focusing module is a field lens or a focusing lens. When the second focusing module is a focusing lens, the second focusing module is disposed between the beam splitter and the galvanometer system; when the second focusing module is a field lens, the second focusing module is disposed in the optical path between the galvanometer system and the working plane.

[0011] As a further preferred embodiment of the present invention, the automatic focusing system of the 3D printing equipment further includes an attenuation mirror and a filter. The attenuation mirror and the filter are sequentially disposed between the first focusing module and the beam splitter, so that the laser emitted by the beam splitter is attenuated and filtered in sequence to adjust the optical intensity to the detection range of the optical detector, and after being converged by the first focusing module, it is collected by the photodetector.

[0012] As a further preferred embodiment of the present invention, the photodetector is a photodiode, a photomultiplier tube, a CCD or CMOS, an avalanche photodiode, or a single-photon detector.

[0013] The present invention also provides a 3D printing device, which includes the 3D printing device autofocus system described in any of the above claims.

[0014] The present invention also provides an autofocusing method for the autofocusing system of the 3D printing equipment described in any one of the above claims, which includes the following steps:

[0015] The laser is adjusted to a preset power to emit light, and the photodetector collects at least the laser light reflected by the working plane;

[0016] The control system receives reflected light collected by the photodetector in real time and converts it into electrical signal data. By adjusting the position of the collimator and / or the height of the working plane, the intensity of the received electrical signal data changes until the electrical signal received by the control system is the strongest. At this point, the control system stops adjusting the position of the collimator and / or the height of the working plane, and the automatic focusing is completed.

[0017] As a further preferred embodiment of the present invention, adjusting the position of the collimator and / or the height of the working plane to cause variations in the strength of the received electrical signal data specifically includes:

[0018] The collimator position is fixed, and the working plane is adjusted vertically via the drive system; or the working plane height is fixed, and the collimator position is adjusted via the drive system to cause variations in the strength of the received electrical signal data.

[0019] The automatic focusing system, method, and 3D printing equipment of the present invention, by adopting the above technical solutions, have the following beneficial technical effects:

[0020] 1. In the automatic focusing system of the 3D printing equipment of the present invention, the photoelectric detector used for detection does not need to be placed on the working plane, and the position can be flexibly placed, thereby avoiding too much manual operation on the working plane and making laser focus adjustment convenient.

[0021] 2. Compared with the prior art, the present invention does not require the detection device to be placed on the working plane, thus it is not limited by the placement position, and can realize focus detection at any position on the full-width surface; moreover, compared with the detection devices of the prior art, which may cause errors due to the position deviation of the working plane, the present invention can more accurately detect the light spot situation on the real working surface, that is, it has the advantages of high precision, online and real-time when determining the light spot focusing position.

[0022] 3. This invention uses a sensitive photoelectric detection method to obtain high-precision real-time detection data. Combined with automatic collimator position adjustment and / or working plane height adjustment, automatic focusing of the laser working plane can be achieved, thereby improving the debugging efficiency and automation level of 3D printing equipment.

[0023] 4. This invention directly adjusts the working plane (i.e. the actual printing plane) of the 3D printing equipment or directly adjusts the position of the collimator of the optical path system in the 3D printing equipment for focusing. Once the focus is successful, 3D printing can be carried out directly, thus ensuring the accuracy of the 3D printing equipment calibration.

[0024] 5. The automatic focusing system of the 3D printing equipment of the present invention adds a beam splitter and a photodetector to the existing optical path system of the 3D printing equipment. Based on the coaxial optical system, the laser wavelength reflected by the coaxial optical path can be separated from the main optical path to achieve independent detection of the target laser signal. The focusing position is determined by searching the detection signal intensity when the optical path moves, thereby realizing the focusing function. That is, the overall system cost is low, the modification is small, and the space occupied by the equipment cavity is small. Attached Figure Description

[0025] Figure 1 This is a structural block diagram of an embodiment of the automatic focusing system for 3D printing equipment of the present invention;

[0026] Figure 2 This is a structural block diagram of Embodiment 2 of the automatic focusing system for the 3D printing equipment of the present invention;

[0027] Figure 3 This is a structural block diagram of Embodiment 3 of the automatic focusing system for the 3D printing equipment of the present invention;

[0028] Figure 4 An optical schematic diagram of Embodiment 3 of the automatic focusing system of the 3D printing equipment of the present invention;

[0029] Figure 5 This is a structural block diagram of Embodiment 4 of the automatic focusing system for the 3D printing equipment of the present invention;

[0030] Figure 6 This is a structural block diagram of Embodiment 5 of the automatic focusing system for the 3D printing equipment of the present invention;

[0031] Marked in the image:

[0032] 1. Laser; 2. Collimator; 3. Beam splitter; 4. First mirror; 5. Second mirror; 6. Field mirror; 7. Working plane; 8. Attenuation filter group; 9. First focusing module; 10. Photodetector; 11. Control system; 12. Quarter-wave plate. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0034] Example 1

[0035] like Figure 1 As shown, the automatic focusing system of the 3D printing equipment in this embodiment includes a laser 1, a collimator 2, a beam splitter 3, a galvanometer system (also referred to as a galvanometer), a second focusing module, a first focusing module 9, a photodetector 10, and a control system 11. The laser emitted by the laser 1 sequentially enters the collimator 2 and the beam splitter 3, and after transmission through the beam splitter 3, it enters the galvanometer system and the second focusing module. After deflection by the galvanometer system and focusing by the second focusing module, it enters the working plane 7, which has a reflective function for the laser. The reflected light, after deflection by the galvanometer system and focusing by the second focusing module, returns to the beam splitter 3 and, after reflection by the beam splitter 3, enters the first focusing module 9 for focusing. The photodetector 10 collects the focused laser light and converts it into an electrical signal.

[0036] The control system 11 receives electrical signal data from the photodetector 10 in real time and adjusts the position of the collimator 2 and / or the height of the working plane 7 to vary the strength of the received electrical signal data until the electrical signal received by the control system 11 is at its strongest. At this point, the adjustment of the collimator 2 position and / or the height of the working plane 7 is stopped, and automatic focusing is completed. The position of the collimator 2 and the height of the working plane 7 at this time are the optimal positions, and subsequent 3D printing can be performed according to these positions. The working plane 7 in this application is the actual 3D printing working surface, which allows for more accurate detection of the light spot on the actual printing surface, providing advantages such as high precision, online operation, and real-time capability in determining the light spot focusing position.

[0037] It should be noted that the photodetector 10 mainly utilizes the reflected signal from the working plane 7 for detection. The detection target is consistent with the actual working area of ​​the laser. In fact, the detection signal is mainly the laser signal reflected by the working plane 7, and may also include the optical radiation signal formed after the laser acts on the working plane. The working plane 7 of this application needs to have the function of reflecting the laser emitted by the laser 1. In specific implementations, the powder material or the substrate or base plate without powder generally has the function of reflection. Preferably, the working plane 7 is a metal substrate or powder material, which has a better reflection effect.

[0038] In a specific implementation, the 3D printing equipment's automatic focusing system also includes a drive system for adjusting the position of the collimator 2 and the height of the working plane 7. For example, the position of the focused light spot on the detection plane can be obtained by searching for the position of the strongest light intensity detected on the working plane 7.

[0039] Specifically, the laser 1 emits a low-power laser, preferably with a power of 1-30W. The control system 11 can be a host computer or a device with processing and control functions, and there are no restrictions on its application. The main function of the beam splitter 3 is to separate the laser emitted by the laser 1 from the laser reflected by the working plane 7. For example, when the laser is transmitted from the laser 1 to the working plane 7 (forward direction), approximately 50% of the light intensity can be transmitted, while when the laser is transmitted from the working plane 7 to the beam splitter 3 (reverse direction), more than 99% of the reflected light can be reflected.

[0040] In one specific implementation, the photodetector 10 is a photodiode, photomultiplier tube, CCD or CMOS, avalanche photodiode, single-photon detector, or other photodetector components. It is used to determine whether the laser is focused at the current working position by acquiring and analyzing the electrical signal after photoelectric conversion. Specifically, the determination method involves adjusting the laser beam to search for and detect the position of the strongest reflected light signal; this position is the focusing position of the laser in the current state.

[0041] Specifically, the second focusing module is a field lens 6 or a focusing lens. When the second focusing module is a focusing lens, the focusing lens is positioned between the beam splitter 3 and the galvanometer system; when the second focusing module is a field lens 6, the field lens 6 is positioned in the optical path between the galvanometer system and the working plane 7, such as... Figure 1 As shown.

[0042] Example 2

[0043] This embodiment is a preferred solution of this application. Compared with Embodiment 1, it adds an attenuation mirror and a filter, and the second focusing module is a focusing mirror. The attenuation mirror and filter installed before the photodetector can filter out stray light outside the laser band and adjust the laser power to a suitable level, thereby making the autofocus of this application more accurate.

[0044] like Figure 2 As shown, the automatic focusing system of the 3D printing equipment in this embodiment includes a laser 1, a collimator 2, a beam splitter 3, a galvanometer system, a first focusing module 9, a focusing lens, a photodetector 10, an attenuator, a filter, and a control system 11. The laser emitted by the laser 1 sequentially enters the collimator 2 and the beam splitter 3, and after transmission through the beam splitter 3, it enters the focusing lens and the galvanometer system. After being focused by the focusing lens and deflected by the galvanometer system, it enters the working plane 7, which has a reflective function for the laser. The reflected light from the working plane 7 returns to the beam splitter 3 after being focused by the focusing lens and deflected by the galvanometer system. Reflected by the beam splitter 3, it sequentially enters the attenuator, the filter, and the first focusing module 9. The photodetector 10 collects the laser output from the first focusing module 9 and converts it into an electrical signal.

[0045] The control system 11 is used to receive electrical signal data from the photodetector 10 in real time, and adjust the position of the collimator 2 and / or the height of the working plane 7 to make the received electrical signal data vary in strength, until the electrical signal received by the control system 11 is the strongest, at which point the adjustment of the position of the collimator 2 and / or the height of the working plane 7 is stopped, and automatic focusing is completed.

[0046] Example 3

[0047] This embodiment is another preferred solution of this application. Compared with embodiment two, a quarter-wave plate 12 is added, and the second focusing module is a field lens 6. The quarter-wave plate 12 is disposed between the beam splitter 3 and the galvanometer system, or between the beam splitter 3 and the second focusing module, to change the polarization state of the reflected light, so that the beam splitter 3 can reflect more laser light to the attenuation mirror.

[0048] like Figure 3 and Figure 4 As shown, the automatic focusing system of the 3D printing equipment in this embodiment includes a laser 1, a collimator 2, a beam splitter 3, a galvanometer system, a first focusing module 9, a field lens 6, a photodetector 10, an attenuator, and a filter. Figure 4The attenuator and filter are collectively referred to as the attenuation filter assembly 8) and the control system 11. The laser emitted by the laser 1 is sequentially incident on the collimator 2 and the beam splitter 3, and after transmission through the beam splitter 3, it is incident on the galvanometer system and the field lens 6. After deflection by the galvanometer system and focusing by the field lens 6, it is incident on the working plane 7, which has a reflective function for the laser. This ensures that the reflected light from the working plane 7 returns to the beam splitter 3 after deflection by the galvanometer system and focusing by the field lens 6. After reflection by the beam splitter 3, it is sequentially incident on the attenuator, the filter, and the first focusing module 9. The photodetector 10 collects the laser output from the first focusing module 9 and converts it into an electrical signal.

[0049] The control system 11 is used to receive electrical signal data from the photodetector 10 in real time, and adjust the position of the collimator 2 and / or the height of the working plane 7 to make the received electrical signal data vary in strength, until the electrical signal received by the control system 11 is the strongest, at which point the adjustment of the position of the collimator 2 and / or the height of the working plane 7 is stopped, and automatic focusing is completed.

[0050] The galvanometer system includes a first reflecting mirror 4 and a second reflecting mirror 5.

[0051] Example 4

[0052] This embodiment is another preferred solution of this application. Compared with embodiment three, the only difference is that the second focusing module is a focusing lens.

[0053] like Figure 5 As shown, the automatic focusing system of the 3D printing equipment in this embodiment includes a laser 1, a collimator 2, a beam splitter 3, a galvanometer system, a first focusing module 9, a focusing lens, a photodetector 10, an attenuator, a filter, and a control system 11. The laser emitted by the laser 1 sequentially enters the collimator 2 and the beam splitter 3, and after transmission through the beam splitter 3, it enters the focusing lens and the galvanometer system. After being focused by the focusing lens and deflected by the galvanometer system, it enters the working plane 7, which has a reflective function for the laser. The reflected light from the working plane 7 returns to the beam splitter 3 after being focused by the focusing lens and deflected by the galvanometer system. Reflected by the beam splitter 3, it sequentially enters the attenuator, the filter, and the first focusing module 9. The photodetector 10 collects the laser output from the first focusing module 9 and converts it into an electrical signal.

[0054] The control system 11 is used to receive electrical signal data from the photodetector 10 in real time, and adjust the position of the collimator 2 and / or the height of the working plane 7 to make the received electrical signal data vary in strength, until the electrical signal received by the control system 11 is the strongest, at which point the adjustment of the position of the collimator 2 and / or the height of the working plane 7 is stopped, and automatic focusing is completed.

[0055] Example 5

[0056] This embodiment is another preferred solution of this application. Compared with embodiment four, the only difference is the addition of a laser absorption pool. Since 50% of the light intensity is transmitted in the forward direction, the rest of the light may be reflected. This embodiment can absorb the reflected light by adding a laser absorption pool, thereby preventing laser leakage and making the automatic focusing system of the 3D printing equipment of the present invention safer.

[0057] like Figure 6 As shown, the automatic focusing system of the 3D printing equipment in this embodiment includes a laser 1, a collimator 2, a beam splitter 3, a galvanometer system, a first focusing module 9, a focusing lens, a photodetector 10, an attenuator, a filter, a laser absorption cell, and a control system 11. The laser emitted by the laser 1 sequentially enters the collimator 2 and the beam splitter 3, and after transmission through the beam splitter 3, it enters the focusing lens and the galvanometer system. After being focused by the focusing lens and deflected by the galvanometer system, it enters the working plane 7, which has a reflective function for the laser. The reflected light from the working plane 7 returns to the beam splitter 3 after being focused by the focusing lens and deflected by the galvanometer system. Reflected by the beam splitter 3, it sequentially enters the attenuator, the filter, and the first focusing module 9. The photodetector 10 collects the laser output from the first focusing module 9 and converts it into an electrical signal. The beam splitter 3 is also connected to a laser absorption cell for absorbing the reflected laser.

[0058] The control system 11 is used to receive electrical signal data from the photodetector 10 in real time, and adjust the position of the collimator 2 and / or the height of the working plane 7 to make the received electrical signal data vary in strength, until the electrical signal received by the control system 11 is the strongest, at which point the adjustment of the position of the collimator 2 and / or the height of the working plane 7 is stopped, and automatic focusing is completed.

[0059] Example 6

[0060] This embodiment provides a 3D printing device, which includes the 3D printing device autofocus system described in any of the above embodiments.

[0061] Example 7

[0062] The autofocusing method of the 3D printing equipment autofocusing system in this embodiment includes the following steps:

[0063] Laser 1 is adjusted to a preset power to emit light, and photodetector 10 collects at least the laser light reflected by the working plane 7;

[0064] The control system 11 receives the reflected light collected by the photodetector 10 in real time and converts it into electrical signal data. By adjusting the position of the collimator 2 and / or the height of the working plane 7, the intensity of the received electrical signal data changes until the electrical signal received by the control system 11 is the strongest. At this point, the control system 11 stops adjusting the position of the collimator 2 and / or the height of the working plane 7, and the automatic focusing is completed.

[0065] Specifically, adjusting the position of the collimator 2 and / or the height of the working plane 7 to cause variations in the strength of the received electrical signal data includes:

[0066] The collimator 2 is fixed in position, and the working plane 7 is adjusted vertically via the drive system; or the working plane 7 is fixed in height, and the collimator 2 is adjusted via the drive system to cause variations in the strength of the received electrical signal data. For example, if the electrical signal weakens when the height of the working plane is continuously adjusted upwards, the height of the working plane is then adjusted downwards, which may strengthen the electrical signal until the electrical signal strength is at its highest, at which point the adjustment is stopped.

[0067] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An automatic focusing system for a 3D printing device, characterized in that, The system includes a laser, a collimator, a beam splitter, a galvanometer system, a first focusing module, a second focusing module, a photodetector, and a control system. The laser emitted by the laser sequentially enters the collimator and the beam splitter, and after transmission through the beam splitter, it enters the galvanometer system and the second focusing module. After deflection by the galvanometer system and focusing by the second focusing module, it enters a working plane that reflects the laser light. The reflected light, after deflection by the galvanometer system and focusing by the second focusing module, returns to the beam splitter, and is then reflected by the beam splitter and focused by the first focusing module. The photodetector collects the laser light output from the first focusing module and converts it into an electrical signal. The control system is used to receive electrical signal data from the photodetector in real time, and adjust the position of the collimator and / or the height of the working plane to make the received electrical signal data change in strength until the electrical signal received by the control system is the strongest, at which point the adjustment of the position of the collimator and / or the height of the working plane is stopped, and automatic focusing is completed. The laser emits laser power of 1-30W, and the working plane is a metal substrate or powder material; The second focusing module is a field lens or a focusing lens. When the second focusing module is a focusing lens, it is located between the beam splitter and the galvanometer system. When the second focusing module is a field lens, it is located in the optical path between the galvanometer system and the working plane.

2. The automatic focusing system for 3D printing equipment according to claim 1, characterized in that, The 3D printing equipment's automatic focusing system also includes a drive system for automatically adjusting the position of the collimator and the height of the working plane.

3. The automatic focusing system for 3D printing equipment according to claim 1, characterized in that, The 3D printing equipment's autofocus system also includes a quarter-wave plate, which is disposed between the beam splitter and the galvanometer system, or between the beam splitter and the second focusing module, to change the polarization state of the reflected light.

4. The automatic focusing system for 3D printing equipment according to claim 1, characterized in that, The 3D printing equipment's autofocus system also includes an attenuation mirror and a filter. The attenuation mirror and the filter are sequentially arranged between the first focusing module and the beam splitter, so that the laser emitted by the beam splitter is attenuated and filtered in sequence to adjust the optical intensity to the detection range of the optical detector, and after being converged by the first focusing module, it is collected by the photodetector.

5. The automatic focusing system for 3D printing equipment according to any one of claims 1 to 4, characterized in that, The photodetector is a photodiode, photomultiplier tube, CCD, CMOS, or single-photon detector.

6. A 3D printing device, characterized in that, Includes the 3D printing equipment autofocus system as described in any one of claims 1 to 5.

7. An automatic focusing method using the automatic focusing system of the 3D printing equipment according to any one of claims 1 to 5, characterized in that, Includes the following steps: The laser is adjusted to a preset power to emit light, and the photodetector collects at least the laser light reflected by the working plane; The control system receives reflected light collected by the photodetector in real time and converts it into electrical signal data. By adjusting the position of the collimator and / or the height of the working plane, the intensity of the received electrical signal data changes until the electrical signal received by the control system is the strongest. At this point, the control system stops adjusting the position of the collimator and / or the height of the working plane, and the automatic focusing is completed.

8. The autofocus method according to claim 7, characterized in that, The intensity of the received electrical signal data can be varied by adjusting the position of the collimator and / or the height of the working plane. Specifically, this includes: The collimator position is fixed, and the working plane is adjusted vertically via the drive system; or the working plane height is fixed, and the collimator position is adjusted via the drive system to cause variations in the strength of the received electrical signal data.

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