Laser class testing device and method for at least partially automated verification of a laser class

Abstract

To simplify and automate the verification of a laser class of a laser module (2), a laser class testing device (1) is proposed, which comprises a movable optical measuring device (7) such that a light power measuring unit (10) and a sensor (11) for detecting a 2D laser pattern (9) generated by the laser module (2) can each be automatically positioned in the beam path of the laser module (2). Therefore, both a local light power measurement and a local beam profile measurement can be carried out automatically using the laser class testing device (1). Based on these two measurements, the laser class testing device (1) can automatically check whether the laser module (2) complies with the specified laser class or not.In addition, the laser class testing device (1) can comprise an accommodation optics (12) with the aid of which the 2D laser pattern (9) to be measured can be imaged onto the sensor (11) at different magnifications during the beam profile measurement in order to simulate different accommodation states.

Description

[0001] The invention relates to a laser class testing device that is intended and configured to perform at least partially (or fully) automated verification of a laser class with respect to a laser module to be measured. During the actual measurement, the laser module is naturally inserted into the testing device, more precisely into a holder for inserting and aligning the laser module of the testing device. In other words, the laser class testing device can thus independently verify whether the optical properties of a laser beam emitted by the laser module are still within the standard specified for a specific laser class. In addition to the holder, the laser class testing device also comprises an optical measuring device for measuring a 2D laser pattern, such as a laser line, wherein the 2D laser pattern is generated by / the laser beam emitted by the laser module to be measured.Furthermore, the laser class testing device comprises at least one controller for the automated control of the optical measuring device.

[0002] This controller can be implemented, for example, in the form of or as part of a control and regulation system, for example, using a commercially available computer (PC) and / or a microcontroller (µC). If a PC is used as the main controller, it can control and regulate numerous other subordinate controllers, such as microcontrollers in actuators. The PC can, in a conventional manner, provide the user with a graphical user interface for operating the laser class testing device and / or for visualizing measurement results. The task of the controller is therefore to control the laser class testing device in such a way that it can automatically verify the laser class of the laser module by automatically performing optical measurements.

[0003] The invention further relates to a method for at least partially automated determination and / or verification of a laser class of a laser module to be measured. In this method, the laser module to be measured is manually or automatically inserted into a receptacle of a laser class testing device, and a laser beam to be measured is generated with the laser module.

[0004] The state of the art already offers a variety of approaches to verifying the respective laser class of, for example, a line laser module. An important background here is standard 60825-1, which was last updated in 2022 as a German standard, and which specifies exactly how the beam profile of a laser must be measured to determine which laser class it belongs to.

[0005] Often, however, this simply involves simulating the laser's beam behavior, which is permitted by the standard. However, a safety margin of 20-50% must typically be applied to the simulation, preventing the laser from operating at the high power level that would be fundamentally possible for the respective laser class. Accordingly, the laser line will be less bright. Another frequently pursued approach is to classify the laser in a higher laser class, e.g., Class 3B. In this case, however, the manufacturer no longer guarantees that the laser is eye-safe.

[0006] In principle, it is also possible to guarantee high reliability in meeting the laser class requirements by applying a very tight product design. However, a tight product design, i.e., strict specifications regarding the quality of the optical components and their tolerances, typically results in particularly expensive manufacturing or a complex and therefore expensive selection and selection of individual components. This is therefore also not an approach that can be used to provide very bright and simultaneously eye-safe laser modules cost-effectively.

[0007] However, there is a strong demand in the market for eye-safe laser devices. Customers particularly want to see evidence that the eye-safe lasers have been measured very precisely and that the laser power in the laser module is therefore set high enough to produce the brightest possible laser line. In other words, the respective laser class must be utilized to the greatest possible extent to achieve the brightest possible laser. This can be achieved by approaching the maximum permissible power at which the respective laser class is just barely complied with, without considering safety factors.

[0008] A second problem is that laser class verification is often performed manually on optical measurement benches with multiple degrees of freedom, meaning that typically only a few trained and experienced users are eligible to perform such individual or complex measurements. While 100% testing, i.e., testing all manufactured lasers, would be desirable, manual testing is not cost-effective.

[0009] DE 10 2020 203 831 A1, for example, discloses a system for qualifying laser light sources, which includes a telescopic beam-shaping optics system that can be adapted by exchanging individual components. This device can be used to determine the laser safety class of a laser beam with an elliptical or simply astigmatic beam profile.

[0010] From DE 10 2021 202 947 A1, an at least partially automated method for carrying out a system test of a laser processing system is previously known, with which the system is prepared for laser processing to be carried out with the system, in particular by checking the correct function of a scanning device with which a laser beam used for material processing is deflected.

[0011] Based on this background, the present invention is based on the object of providing a measuring station, more specifically a laser class testing station or a laser class testing device, with which a 100% test of fully assembled laser modules can be carried out quickly and efficiently at the end of production. Furthermore, the invention also aims to provide an associated method with which an at least partially automated verification of the laser class can be carried out quickly and efficiently.

[0012] To achieve this object, the invention proposes a laser class testing device, i.e., a device, according to claim 1. In particular, to achieve the object, the invention proposes, for a laser class testing device as described above, that its optical measuring device comprises the following components: a light power measuring unit for determining a light power (for example, measured in mW); a sensor for at least partially detecting the 2D laser pattern (therefore, the entire pattern does not necessarily have to be detected); and finally, accommodation optics, with which an optical image of the 2D laser pattern can be adapted to an active sensor surface of the sensor.Furthermore, to achieve the object, it is provided that the optical measuring device and / or the holder are designed to be movable, in such a way that a relative movement between the optical measuring device and the laser module held by the holder, controlled by the controller, can be carried out automatically.

[0013] With such a testing device, the laser class of a laser module can be checked or verified automatically. Time-consuming and costly manual verification becomes unnecessary.

[0014] The laser class testing device according to the invention can, of course, also include the laser module inserted into the holder. The use of such a testing device makes it possible, in particular, to design and manufacture laser modules very close to the maximum permissible power, because such a testing device enables 100% testing, so that the laser class can be reliably maintained for each individual laser module manufactured. As a result, laser modules can be produced that are eye-safe and simultaneously exhibit approximately the maximum possible (within the scope of eye safety) brightness of the 2D laser pattern / laser line emitted by the laser module.

[0015] This test device is primarily intended and designed for measuring static 2D laser patterns, in particular a laser line generated by a laser module. Laser lines can be generated, for example, using cylindrical lenses in the laser module. However, if the laser module includes a diffractive optical element (DOE), the laser pattern can also be more complex (e.g., as a cross, a circular line, or a geometric pattern such as a point cloud or a regular laser line grid).

[0016] However, a laser class testing device according to the invention can also be used to measure dynamic 2D laser patterns, which can be obtained, for example, by actively deflecting a laser beam generated by a laser module. In this case, the laser module itself can, in particular, comprise such an active beam deflection unit, which can then be controlled by the controller of the laser class testing device or, for example, activated automatically when the laser module is switched on.

[0017] The laser class testing device can of course also include a suitable voltage and / or power supply as well as the necessary electrical connection means for operating the respective laser module to be measured.

[0018] The holder can be designed in the form of a mount, particularly as a "tray" and / or with markings and mechanical stops. This ensures that the respective laser module can only be inserted into the holder in a specific, predefined orientation and position. This allows a rough alignment of the 2D laser pattern relative to the test fixture without the need for large actuators. In particular, this may make it possible to dispense with a laser beam rotation actuator, as explained in more detail below (as an optional feature of the test fixture).

[0019] Accommodation is usually understood as the adjustment of the human eye to different object distances. This is achieved by actively increasing the refractive power of the eye's dioptric apparatus. The maximum amount by which the refractive power can be increased (measured in diopters) is referred to as the amplitude of accommodation. The accommodation optics can therefore be designed in particular to simulate an optical imaging of the laser pattern onto the retina through a lens in a human eye, with the (typically flat) active sensor surface of the sensor then simulating the (curved) retina.

[0020] With the testing device according to the invention, parameters relevant to eye safety of the laser module, such as the so-called C6 factor required for determining / verifying the laser class according to standard 60825-1, can be determined quickly and at least partially or fully automated. This makes it economically possible, for example, to implement a 100% laser class test of manufactured laser modules with the testing device.

[0021] The laser class testing device can, for example, be implemented as a compact optical measuring station, which can also be designed as a mobile device, which can be easily and safely operated by persons with only rudimentary training and without in-depth knowledge of optics in order to carry out a semi- or fully automated verification of the laser class of a laser module.

[0022] To increase user safety, the laser class testing device can include an openable housing that prevents laser light from escaping from the housing into the environment during automated measurements. This creates a safe laser class testing station that can be operated without laser goggles.

[0023] The laser class testing device according to the invention described above can be further developed as follows: For example, it can be provided that the accommodation optics are designed to be variable in their focal length or position. Preferably, the focal length and / or position of the accommodation optics can be automatically adjusted by the controller using a control signal.

[0024] In principle, it is also preferable if the controller of the laser class testing device is designed to implement a method according to the invention as described herein or according to one of the method claims, which are explained in more detail below.

[0025] In the simplest case, the accommodation optics can comprise a single lens that can be moved in space using an actuator controlled by the controller, allowing for automated adjustment of the image of the 2D laser pattern onto a sensor surface of the sensor. It is also conceivable to implement the accommodation optics with multiple optical lenses that can be moved relative to one another. However, embodiments such as those described below with at least one tunable lens are preferred, because in this case, the tunable lens does not need to be moved spatially, which is advantageous for fast, efficient, and accurate measurements with low vibration.

[0026] The accommodation optics can comprise a tunable optical lens, i.e., a lens with a variable focal length. This makes it possible to automatically adjust the image of the 2D laser pattern through the accommodation optics onto a sensory surface of the sensor by tuning the tunable lens. In other words, the accommodation optics can thus comprise adaptive optics with which a power density occurring on the retina (intensity in mW / mm 2 ) can be reproduced.

[0027] The tunable lens can be designed, for example, as a tunable membrane lens and / or a tunable liquid lens and / or a tunable liquid crystal lens. Tunable liquid crystal lenses offer the advantage of a very compact design while simultaneously allowing very efficient and motionless tuning of the optical focal length. They can be used particularly in laser applications because the optical dispersion of the liquid crystals plays a less significant role in the measurement due to the very narrow wavelength range of the laser radiation.

[0028] The sensor used to measure the beam profile of the 2D laser pattern can, in the simplest case, be configured as a 1D line sensor, i.e., in particular, based on a 1D sensor array. However, preferred sensor configurations are 2D sensors, i.e., preferably based on a two-dimensional active sensor surface. Such a sensor surface can allow the sensor to simultaneously detect at least two different beam widths.

[0029] When using a 1D sensor, the 2D laser pattern can be optically scanned, for example, by scanning the 2D laser pattern along at least one axis (e.g., the x-axis) with the 1D sensor. A relative movement between the laser module and the 1D sensor can be performed for this scanning. It is preferred if the axis of the 1D sensor (e.g., the y-axis) runs perpendicular to the scan axis (e.g., the x-axis). This allows, for example, a local y-line width for different x-values of a laser line of the laser module aligned along the x-direction to be measured automatically using the test device.

[0030] However, if a 2D sensor is used, especially in the same way, two beam widths (e.g. x-width and y-width) can be detected simultaneously by the 2D sensor at different points of the 2D laser pattern.

[0031] The accommodation optics, in particular the aforementioned tunable lens, can thus comprise an electrical actuator for adjusting an optical focal length of the accommodation optics (in particular for the optical accommodation of the accommodation optics). It is preferred if the accommodation optics comprises a temperature sensor so that the accommodation can be carried out with temperature compensation.

[0032] As already mentioned at the beginning, in the laser class testing device according to the invention, the optical measuring device and / or the aforementioned receptacle in which the laser module is held is designed to be movable, specifically in such a way that the said relative movement between the optical measuring device and the laser module held by the receptacle can be carried out automatically, namely controlled by the controller. For example, for this purpose, the optical measuring device can be moved automatically in space, preferably along at least two axes (x, y axes) that run perpendicular to a z-propagation direction of the laser beam. This makes it possible to optically scan the 2D laser pattern using the optical measuring device. Furthermore, it is possible to optically scan a laser line generated by the laser module at different spatial scanning positions using the sensor.

[0033] The aforementioned light power measuring unit can be implemented, for example, using a photoelectric sensor such as a calibrated photodiode. It is particularly preferred if the light power measuring unit is implemented as an integrating sphere, as this enables more robust and accurate measurements of the light power.

[0034] The light power measuring unit can have an optical aperture with a diameter of at least 5 mm; however, it is preferred if the diameter is no more than 10 mm. This optical aperture can then be used to optically scan the 2D laser pattern.

[0035] It can further be provided that a z-distance (along the light propagation direction of the laser beam) between the holder and the light power measuring unit is at least 100 mm. This is advantageous for capturing measurement parameters relevant for verification. Furthermore, said z-distance can also be configured to be variable, for example, by automatically moving the holder together with the laser module along the z-direction. A corresponding z-actuator, for example in the form of a linear motor stage, can be provided for this purpose.

[0036] The sensor used to perform the beam profile measurement can be implemented as a beam profiler. It can also include an image sensor.

[0037] The sensor, in particular the aforementioned beam profiler / 2D sensor, can further be configured to automatically evaluate sensor-detected intensity values based on an algorithm and to determine at least one local beam width, in particular a (y-) line width of the 2D laser pattern / laser line. It is particularly preferred if the sensor is configured to determine two orthogonal beam widths, in particular a local beam diameter.

[0038] A further embodiment provides that the laser class testing device comprises a pneumatic actuator that can be controlled by the controller. The pneumatic actuator can be used to automate a relative movement between the optical measuring device and the laser module inserted in the holder, with the pneumatic actuator moving the measuring device and / or the holder in space for this purpose.

[0039] In particular, the pneumatic actuator can be designed in the form of a linear axis or a linear actuator. In this case, the actuator can execute a linear relative movement between the optical measuring device and the laser module inserted in the holder. The direction of this relative movement can preferably be oriented transversely, in particular perpendicularly, to a beam direction of the laser beam emitted by the laser module.

[0040] Preferably, the pneumatic actuator can also be configured to move the optical measuring device back and forth between a first end position and a second end position. In the first end position, the light power measuring unit can be located in the beam path of the laser module, and in the second end position, the said sensor of the optical measuring device can be located.

[0041] The pneumatic actuator thus allows for rapid switching between optical power measurement and beam profile measurement. Reaching the respective end positions can be automatically detected by the controller using end position sensors. This design is advantageous because, on the one hand, such a pneumatic system is easy to implement and thus cost-effective, while at the same time operating reliably. On the other hand, the invention recognizes that precise adjustment along an x-axis perpendicular to the propagation direction of the laser beam is not necessary because the respective apertures of the optical power meter and the accommodation optics can be selected so large that high travel accuracy is not required to achieve a reliable measurement.

[0042] The laser class testing device can preferably further comprise a pivot actuator, which can also be controlled by the controller and can preferably be implemented by means of a motor. The pivot actuator can automatically pivot the mount and thus the laser module inserted therein about a y-pivot axis. This makes it possible to automatically perform a beam profile measurement of the 2D laser pattern. An advantage of such a configuration is that when pivoting the laser module, a distance between the laser module and the optical measuring device can be essentially or even exactly maintained, which simplifies the optical measurement.

[0043] Finally, the laser class testing device can comprise a laser beam rotation actuator, which can also be controlled by the controller and with which a laser beam emitted by a laser module inserted into the holder can be rotated about its z-propagation direction. More precisely, the rotation actuator rotates the holder and / or the laser module inserted therein, so that the laser beam emitted by the laser module is rotated about its z-propagation direction. With such a configuration, the 2D laser pattern / laser line to be measured can be automatically aligned relative to the optical measuring device by the controller. Depending on the laser pattern and the manufacturing precision of the laser module used, such a rotation actuator may be dispensed with under certain circumstances, particularly if the holder already allows for a rough manual alignment of the laser module relative to the optical measuring device.

[0044] As mentioned, the laser class testing device can also comprise a z-actuator with which a z-distance between the measuring device and the holder can be adjusted, preferably in an automated / controlled manner via the controller.

[0045] To achieve the object, a method according to claim 15 is further proposed, wherein it is preferred if a laser class testing device according to the invention is used, as described above or according to one of the device claims. In particular, in a method for achieving the object as mentioned above, it is proposed according to the invention that a 2D laser pattern generated by the laser beam, i.e., in particular, a laser line, is optically scanned with an optical measuring device of the laser class testing device. For this purpose, at least one relative movement between the optical measuring device and the laser module is carried out automatically (by the laser class testing device).

[0046] Through optical scanning, a hotspot of the 2D laser pattern / laser line can first be automatically identified in terms of light output. Such a hotspot can be defined as a local maximum in light output. Subsequently, a beam profile measurement can be performed at the location of the hotspot using the optical measuring device, preferably also automated, in particular to automatically verify the laser class of the laser module.

[0047] Alternatively or in addition to the previously explained feature, the method according to the invention can also provide that a beam width minimum B min a local beam width of the 2D laser pattern is automatically identified and at the location of this beam width minimum B minAn optical power measurement is performed with the optical measuring device, whereby this optical power measurement is also preferably controlled automatically by the controller. The laser class of the laser module can also be verified in this way, whereby the verification can also preferably be carried out automatically by the controller of the laser class testing device. Both of these approaches can be considered technically equivalent alternatives according to the invention.

[0048] It is further preferred if, during the verification of the laser class, said controller of the laser class testing device automatically determines a ratio P max / B HS from a laser power P max in the hotspot and a local beamwidth in hotspot B HS calculated and taken into account.

[0049] Alternatively or in addition to this, the controller can also use a ratio P SM / B min from a laser power PSM at the location of the previously explained beam width minimum B min and the local beamwidth minimum B min calculate and take into account.

[0050] The described (partially) automated laser class verification method according to the invention can be further developed as follows: It can be provided that, as part of the beam profile measurement, an accommodation optics of the measuring device is automatically detuned, in particular as already described above with reference to the laser class testing device. This is because, preferably, several beam profile measurements can be performed in different accommodation states of the accommodation optics. In other words, a minimum B min (B HS ) = Min(B HS) of a / the local beam width in the hotspot can be determined and / or at least two different local beam widths (e.g. B HS,x and B HS,y ) in the hotspot.

[0051] The quotient of P max / B min (B HS) can be viewed as a worst-case estimate of the C6 factor for the laser module being measured and evaluated accordingly, i.e. automatically evaluated to verify the laser class. The controller can also carry out these processes automatically and thus output / generate a digital test result (laser class complied with YES / NO). As a result, the method according to the invention, in particular using a test device according to the invention, can be used to quickly and efficiently verify whether the laser-under-test (LuT), i.e. the laser module being measured, produces a C6 factor or a laser beam that is still within the standard specified / specified for the laser class to be verified.

[0052] In the optical scanning described above, the recording can remain static in space, at least temporarily or permanently, while the optical measuring device is moved automatically relative to the static laser module.

[0053] However, alternatively or additionally, during optical scanning, the measuring device can remain static in space, at least temporarily, while the laser module is automatically moved relative to the measuring device. Both of these solutions can be considered technically equivalent and, according to the invention, can be used in combination, in particular.

[0054] In the method according to the invention, the hotspot can be determined based on light power values that are recorded with a light power measuring unit (in particular as described above) of the laser class testing device (this recording can also be carried out in particular as described above). In this case, the 2D laser pattern, i.e. in particular the aforementioned laser line, can preferably be automatically scanned along at least one scanning direction (for example, along the x-direction) by means of a first relative movement between the light power measuring unit and the laser module, and a laser light power is measured continuously or at least at regular intervals with the light power measuring unit. In this way, a continuous laser light power profile along the scanning direction can be automatically recorded. Before the first relative movement is carried out, the light power measuring unit should be moved into the beam path of the laser module.This can be done automatically, for example with the help of a pneumatic actuator, as already explained.

[0055] During the beam profile measurement, a sensor of the measuring device, which can in particular be designed as described above, can be automatically placed in the beam path of the laser module and / or it can be provided that this sensor is automatically positioned relative to the 2D laser pattern to be measured by means of a second relative movement between the 2D sensor and the laser module. The second relative movement can in particular be achieved by pivoting the laser module in space. In this way, a respective local beam width of the 2D laser pattern or the laser line can be determined at different points of the 2D laser pattern / laser line. Such a local beam width can in particular be a local beam diameter or a local line width. Before the second relative movement is carried out, the sensor, in particular the beam profiler / 2D sensor, should be moved into the beam path of the laser module.This can also be done automatically, for example with the help of the pneumatic actuator mentioned above.

[0056] During beam profiling, the fixture and thus the laser module installed within it can be automatically pivoted around a y-axis, as previously explained. It is preferable for the y-axis to be orthogonal to the z-axis propagation direction of the laser beam. This allows for a precise x-scan of the laser line to be performed very easily.

[0057] As already mentioned, said at least one relative movement between the optical measuring device and the laser module can preferably be carried out by means of a pneumatic actuator. This applies to both the first relative movement between the light power measuring unit and the laser module and / or the aforementioned second relative movement between the sensor and the laser module. As previously mentioned, such an actuator can be used to move the optical measuring device back and forth between two end positions very easily and efficiently. In other words, it is preferred if the pneumatic actuator moves the measuring device and / or the holder in space. It is important that the described relative movement between the optical measuring device and the laser module can be carried out by the actuation, so that both the light power measuring unit and the sensor can be alternately placed in the beam path of the laser beam of the laser module.

[0058] The invention will now be described in more detail using exemplary embodiments, but is not limited to these embodiments. Further developments of the invention can be derived from the following description of a preferred embodiment in conjunction with the general description, the claims, and the drawings.

[0059] In the following description of various preferred embodiments of the invention, elements which correspond in function are given the same reference numbers even if they have a different design or shape.

[0060] It shows: Fig. 1 a schematic top view of a laser class testing device designed according to the invention, Fig. 2 the laser class testing facility of Fig. 1 seen from the side and Fig. Figure 3 illustrates the intensity profile and the beam width of a laser beam emitted by a laser module.

[0061] The Fig. Figure 1 shows a top view, in a highly schematic form, of a laser class testing device 1 designed according to the invention, which comprises an optical measuring device 7 for measuring a laser line 8, wherein the measuring device 7 is controlled automatically by means of the controller 14 shown. The laser class testing device 1 also comprises a holder 3 in the form of a tray 27, which is mounted on a carriage 25 with a motorized rotation unit, as can be clearly seen in the side view of Fig. 2 can be recognized.

[0062] A laser module 2 is inserted into the holder 3, which comprises a laser light source 5 for generating a laser beam 4 and an associated beam shaping optics 6. As can be clearly seen from the side view of the Fig. 2, the laser module 2 emits the laser beam 4 along the z-direction, whereby this propagation direction is determined by pivoting the holder 3 and thus the laser module 2 inserted therein by the Fig. 2 is possible using a pivot actuator 24. The pivot actuator 24 is formed by a motorized rotation unit of the carriage 25 and can be controlled by the controller 14 via a control line 32.

[0063] Under the supervision of the Fig. 1 clearly shows that the beam-shaping optics 6 generates a laser beam 4 that fans out along the Z-direction, so that a laser line 8 (as a possible 2D laser pattern 9) is generated at some distance from the laser module 2, the optical properties of which are to be measured with the laser class testing device 1. This optical measurement ultimately serves to verify whether the laser module 2, or more precisely its laser beam 4 or the laser line 8, complies with the specifications of a standardized laser class or not. Due to manufacturing variations, the shape of the laser line 8 and / or the optical power generated by the laser light source 5 may vary.

[0064] Under the supervision of the Fig. 1, it can also be clearly seen that the optical measuring device 7 comprises a light power measuring unit 10 and a sensor 11, which are arranged next to each other on the x-axis shown. In the side view of the Fig. 2, the light power measuring unit 10 is therefore not visible, as it is covered by the sensor 11 in front of it. However, a pneumatic actuator 19 can be seen there, with which the entire optical measuring device 7 is moved along the x-direction by an amount Δx (compare Fig. 1). To do this, the controller 14 controls the actuator 19, so that it moves the optical measuring device 7 between a first end position and a second end position. In the first end position, the light power measuring unit 10, or more precisely its optical aperture 18, which is defined by the illustrated diaphragm 29A, is located in the beam path of the laser beam 4.

[0065] In the second end position, which is Fig. 1, the optical aperture 30 of the sensor 11 is located in the beam path of the laser module 2.

[0066] While the light power measuring unit 10 can be used to detect a light power locally in a specific area of the laser line 8, the sensor 11, which in the example of the Fig. 1 is designed as a two-dimensional sensor, more precisely as a beam profiler 15, to detect the laser line 8 as a 2D laser pattern 9. As can be seen in Fig. 1, the sensor 11 does not detect the entire laser line 8, but, due to the restriction by the optical aperture 30, always only a specific section of the laser line 8 in the area of a specific scanning position 16 along the laser line 8.

[0067] The Fig. The situation depicted in Figure 1 corresponds approximately to the situation that could occur if the laser beam 4 emitted by the laser module 2 strikes the retina of an observer. In such a situation, however, the imaging apparatus of the human eye is located in front of the retina, which can lead to the laser radiation being focused onto the retina. This accommodation process is simulated in the laser class testing device using accommodation optics 12, which are arranged in the beam path directly in front of the sensor 11, but still behind the optical aperture 30, as can be clearly seen in Fig. 1 recognizes.

[0068] In the preferred Fig. 1, the accommodation optics 12 is positioned at a specific, non-variable / constant distance from the sensor 11. This means that the accommodation optics 12 are not moved relative to the sensor 11 here. However, the accommodation optics 12 comprises a tunable optical lens 13, the focal length of which can be changed using an electrical actuator 17 controlled by the controller 14. As a result, by appropriately controlling the actuator 17, the lens 13 can be tuned and thus an image of the laser line 8 can be adapted to the sensor surface of the sensor 11. This allows different accommodation states to be simulated and a corresponding measurement to be carried out with the sensor 11. In the example shown, the lens 13 is implemented as a tunable liquid lens, which can be electrically actuated using the electrowetting effect.Technically equivalent to this would be the use of a tunable membrane lens or, for example, a tunable liquid crystal lens, since such concepts also allow the focal length of the lens 13 to be tuned in very fine gradations.

[0069] The beam profiler 15 comprises a two-dimensional active sensor surface 35 and is therefore designed as a 2D sensor.

[0070] The light power measuring unit 10, on the other hand, is implemented in the form of an integrating sphere 31, has an optical aperture 18 between 5-10 mm and a calibrated photodiode 33 with which the 2D laser pattern 9 / laser line 8 can be optically scanned.

[0071] The optical measuring device 7 can not only be moved along the x-direction using the pneumatic actuator 19, but the accommodation optics 12 can also be adjusted / adjusted in its y-height, for example. The holder 3 is also designed to be movable in its y-height. Furthermore, the laser class testing device 1 includes a motorized linear axis 26, with which the z-distance between the laser module 2 held in the holder 3 and the measuring device 7 can be adjusted. The motorized linear axis 26 thus forms a z-actuator 23.

[0072] As explained, a relative movement between the measuring device 7 and the inserted laser module 2 can be carried out automatically with the actuator 19, whereby for this purpose the actuator moves the measuring device 7 in space.

[0073] Using the swivel actuator 24, the controller 14 can swivel the laser module 2 in a swivel movement 34 about the y-axis 28. As the top view of the Fig. 1 shows, when the laser module 2 is pivoted clockwise, the laser line 8 can be continuously optically scanned by the sensor 11 in the scanning direction 20 shown (to the left in the figure). In other words, a relative movement between the measuring device 7 and the laser module 2 can be carried out automatically, controlled by the controller 14. The sensor 11 can thus optically scan the laser line 8 generated by the laser module 2 at different spatial scanning positions 16 along the laser line 8.

[0074] During this optical scanning, the beam profiler records 15 intensity values (e.g. measured in mW / mm 2) and evaluates these automatically based on an algorithm to determine a local beam width 21, as described in Fig. 3 is illustrated: For example, the y-width 21 of the Fig. 3 shown laser beam 8 along the x-direction and also the intensity (measured in mW / mm 2 ) also fluctuate along the x-direction. The dotted line illustrates the outer boundary of the laser beam 8, defined by the intensity drop to the value 1 / e 2 the maximum intensity.

[0075] In Fig. 1, the dashed box also indicates that the laser class testing device can / could also include a laser beam rotation actuator 22 in order to be able to rotate the laser beam 4 about its z-propagation direction, which can be useful for complex 2D laser patterns 9.

[0076] Based on the Fig.1 to 3 also clearly illustrate the method according to the invention, which can be used to verify (at least partially automatically) whether the laser module 2 to be measured actually complies with the intended laser class. To do so, the laser module 2 must first be inserted into the receptacle 3 of the laser class testing device 1 (e.g., manually or automatically using a robot) in order to generate the laser beam 4 to be measured after appropriate electrical contacting of the laser module 2. Subsequently, the laser line 8 generated by the laser beam 4 is optically scanned using the optical measuring device 7 of the laser class testing device 1.For this purpose, the laser class testing device 1 independently and automatically carries out a relative movement between the measuring device 7 and the laser module 2 by pivoting the holder 3 together with the laser module 2 inserted therein about the pivot axis 28 using the pivot actuator 24.

[0077] The actual verification of the laser class can basically be achieved in two different ways: First, the controller 14 can first introduce the light power measuring unit 10 of the measuring device 7 into the beam path of the laser module 2 by appropriately controlling the pneumatic actuator 19. Subsequently, the controller 14 continuously records the local light power (in mW) of the laser line 8 by pivoting the laser module 2 about the pivot axis 28 as previously explained, and automatically identifies a maximum of this light power as a hotspot. The controller 14 then stores the x-coordinate of this hotspot, subsequently moves the sensor 11 into the beam path of the laser module 2 using the actuator 19, and then automatically performs a beam profile measurement using the sensor 11 at the previously identified x-position of the hotspot by pivoting the laser module 2 again. From the previously sensor-detected laser power P max in the hotspot and the local beam width B determined during the beam profile measurement HSAt the location of the hotspot (HS), the controller 14 can then verify compliance with the laser class.

[0078] As an alternative to this procedure, or in addition, for example as an additional safeguard, the controller 14 can also be configured to first automatically identify a local beam width 21 of the laser line 8 using the sensor 11 by optically scanning the laser line 8 using the sensor 11. The controller can then then determine the laser power P SM at the location of this beam width minimum B min using the light power measuring unit 10, whereby the controller 14 determines the x-coordinate of the beam width minimum B min and determines the laser power at this x-position using the light power measuring unit 10. The controller 14 can then use the ratio P SM / B minalso verify whether the laser class is complied with.

[0079] In the previously explained variants of an at least partially automated laser class verification according to the invention using the laser class testing device 1 shown in the figures, the controller 14 can also control the accommodation optics 12 within the scope of the beam profile measurement using the sensor 11 and thereby tune it. In this way, the controller 14 can perform several beam profile measurements in different accommodation states, but for example, each at the same location x mthe laser line 8. This allows, for example, the local beam width 21 at this x-location to be determined even more precisely in the sense of a minimum, because the beam width 21 will change accordingly depending on the accommodation state of the accommodation optics 12, so that generally a minimum of the local beam width 21 will only be observed for a specific accommodation state / focal length of the accommodation optics 12.

[0080] By means of the previously explained first relative movement between the light power measuring unit 10 and the laser module 2, namely when the light power measuring unit 10 is located in the beam path of the laser module 2 and the latter is pivoted about the pivot axis 28, a laser light intensity of the laser line 8 can thus be continuously recorded.

[0081] For the beam profile measurement to be carried out, the sensor 11 is then automatically placed in the beam path of the laser module 2 and then, by means of a second relative movement between the sensor 11 and the laser module 2, which is again achieved by pivoting the laser module 2, the respective local beam width 21 is determined, in each case at different x-positions of the laser line 8.

[0082] In summary, to simplify and automate the verification of a laser class of a laser module 2, a laser class testing device 1 is proposed. This device comprises a movable optical measuring device 7, so that a light power measuring unit 10 and a sensor 11 for detecting a 2D laser pattern 9 generated by the laser module 2 can each be automatically positioned in the beam path of the laser module 2. Therefore, the laser class testing device 1 can automatically perform both a local light power measurement and a local beam profile measurement. Based on these two measurements, the laser class testing device 1 can automatically check whether the laser module 2 complies with the specified laser class or not.In addition, the laser class testing device 1 can comprise an accommodation optics 12, with the aid of which the 2D laser pattern 9 to be measured can be imaged at different magnifications onto the sensor 11 during the beam profile measurement in order to simulate different accommodation states. List of reference symbols 1 laser class testing device (in particular designed as a partially or fully automated optical measuring station) 2 laser modules (includes 5 and 6) 3 Recording (from 1 to insert / hold 2) 4 Laser beam (generated by 2) 5 Laser light source (of 2) 6 beam shaping optics (of 2) 7 optical measuring device 8 laser lines 9 2D laser patterns 10 Light output measuring unit 11 Sensor (e.g. 1D line sensor, but preferably designed as a 2D sensor, in particular as an image sensor or beam profiler) 12 tunable accommodation optics (with tunable focal length) 13 optical tunable lens (in particular designed by means of a tunable membrane lens or as a tunable liquid lens) 14 Controller (particularly as part of a control and regulation system and / or implemented by means of a PC or a µC) 15 beam profilers 16 scanning positions (along 8) 17 electric actuator (of 12 and / or 13) 18 optical aperture (out of 10) 19 pneumatic actuator 20 Scanning direction 21 local beam width (e.g. in y-direction) 22 Laser beam rotation actuator 23 z-actuator 24 Swivel actuator 25 carriages with motorized rotation unit 26 motorized linear axes 27 trays 28 Swivel axis (y-axis) 29 aperture 30 optical aperture (out of 11) 31 Ulbricht sphere 32 control line 33 Photodiode 34 Swivel movement 35 active sensor area (of 11 / 15)

Claims

[1] Laser class testing device (1) for the at least partially automated verification of a laser class with respect to a laser module (2) to be measured, comprising - a holder (3) for inserting and aligning the laser module (2), - an optical measuring device (7) for measuring a 2D laser pattern (9) such as a laser line (8) generated by a laser beam (4) emitted by the laser module (2), and - a controller (14) for automatically controlling the optical measuring device (7), characterized by , - that the optical measuring device (7) comprises the following components: - a light output measuring unit (10) for determining a light output; - a sensor (11) for at least partially detecting the 2D laser pattern (9); and - an accommodation optics (12) with which an optical image of the 2D laser pattern (9) can be adapted to an active sensor surface of the sensor (11); and - that the optical measuring device (7) and / or the holder (3) are designed to be movable, in such a way that - that a relative movement between the optical measuring device (7) and the laser module (2) held by the holder (3), controlled by the controller (14), can be carried out automatically. [2] Laser class testing device (1) according to claim 1, wherein the accommodation optics (12) are designed to be variable in their focal length or in their position, - and preferably the focal length and / or the position of the accommodation optics (12) can be automatically adjusted by means of a control signal from the controller (14) and / or - that the controller (14) is configured to implement a method according to one of claims 15 to 21. [3] Laser class testing device (1) according to claim 1 or 2, wherein the accommodation optics (12) comprises a tunable, i.e. variable in its focal length, optical lens (13), - preferably such that by tuning the tunable lens (13) an image of the 2D laser pattern (9) through the accommodation optics (12) onto a sensory surface of the sensor (11) can be automatically adapted. [4] Laser class testing device (1) according to claim 3, wherein the tunable lens (13) is - a tunable membrane lens and / or as - a tunable liquid lens and / or as - a tunable liquid crystal lens is designed. [5] Laser class testing device (1) according to one of the preceding claims, wherein the sensor (11) is - a 1D line sensor, in particular based on a 1D sensor array, or as - a 2D sensor, preferably based on a two-dimensional active sensor surface (35), is designed. [6] Laser class testing device (1) according to one of the preceding claims, wherein the accommodation optics (12), preferably the tunable lens (13), comprises an electrical actuator (17) for adjusting an optical focal length of the accommodation optics (12) / for the optical accommodation of the accommodation optics (12), - preferably wherein the accommodation optics (12) comprises a temperature sensor so that the accommodation can be carried out in a temperature-compensated manner. [7] Laser class testing device (1) according to one of the preceding claims, wherein, to carry out the relative movement, the optical measuring device (7) is automatically positioned in space, - preferably movable along at least two axes (x, y) which run perpendicular to a z-propagation direction of the laser beam (4), - in particular in order to optically scan the 2D laser pattern (9) with the aid of the optical measuring device (7) and / or - preferably in order to be able to optically scan a laser line (8) generated by the laser module (2) at different spatial scanning positions (16) with the sensor (11). [8] Laser class testing device (1) according to one of the preceding claims, wherein the light power measuring unit (10) - by means of a photoelectric sensor such as a calibrated photodiode (33) and / or - is realized as an integrating sphere (31) and / or - an optical aperture (18) with a diameter of at least 5 mm, preferably and at most 10 mm, for optically scanning the 2D laser pattern (9) and / or - wherein a z-distance between the holder (3) and the light power measuring unit (8) is at least 100 mm and / or is designed to be variable. [9] Laser class testing device (1) according to one of the preceding claims, wherein the sensor (11) - is realized by means of a beam profiler (15) and / or - includes an image sensor. [10] Laser class testing device (1) according to one of the preceding claims, wherein the sensor (11), in particular the beam profiler (15) / the 2D sensor (11), is designed to automatically evaluate intensity values detected by sensors on the basis of an algorithm and from this - at least one local beam width (21), in particular a (y-)line width, - preferably to determine two orthogonal beam widths, in particular a local beam diameter, of the 2D laser pattern (8) / the laser line (8). [11] Laser class testing device (1) according to one of the preceding claims, wherein the laser class testing device (1) comprises a pneumatic actuator (19) which can be controlled by the controller (14) and with which a relative movement between the optical measuring device (7) and the laser module (2) inserted in the holder (3) can be carried out automatically, wherein the pneumatic actuator (19) for this purpose moves the measuring device (7) and / or the holder (3) in space, - preferably wherein the pneumatic actuator (19) is designed to move the optical measuring device (7) back and forth between a first end position and a second end position, - particularly preferably wherein in the first end position the light power measuring unit (10) and in the second end position the sensor (11) / the beam profiler (15) are located in the beam path of the laser module (2). [12] Laser class testing device (1) according to one of the preceding claims, wherein the laser class testing device (1) comprises a pivot actuator (24) which can be controlled by the controller (14), preferably implemented by means of a motor, with which the holder (3) and thus the laser module (2) inserted therein can be pivoted automatically about a y-pivot axis (28), - preferably to carry out such a beam profile measurement automatically. [13] Laser class testing device (1) according to one of the preceding claims, wherein the laser class testing device (1) comprises a laser beam rotation actuator (22) which can be controlled by the controller (14) and with which a laser beam (4) emitted by a laser module (2) inserted into the holder (3) can be rotated about its z-propagation direction, - in particular so that the 2D laser pattern / laser line (8) to be measured can be aligned relative to the optical measuring device (7) automatically by the controller (14). [14] Laser class testing device (1) according to one of the preceding claims, wherein the laser class testing device (1) comprises a z-actuator (23) with which a z-distance between the measuring device (7) and the holder (3) can be adjusted, preferably in an automated / controlled manner via the controller (14). [15] Method for at least partially automated determination and / or verification of a laser class of a laser module (2) to be measured, - wherein the laser module (2) is inserted manually or automatically into a receptacle (3) of a laser class testing device (1), in particular designed according to one of the preceding claims, and - wherein a laser beam (4) to be measured is generated with the laser module (2), characterized by , - that a 2D laser pattern (9), in particular a laser line (8), generated by the laser beam (4) is optically scanned with an optical measuring device (7) of the laser class testing device (1), wherein for this purpose at least one relative movement between the optical measuring device (7) and the laser module (2) is carried out automatically, - that by optical scanning, a hotspot of the 2D laser pattern (9) / laser line (8) is first automatically identified with respect to a light output and at the location of the hotspot, a beam profile measurement is carried out with the optical measuring device (7), preferably automatically, in order to verify the laser class of the laser module (2) and / or - that the optical scanning initially produces a beam width minimum B mina local beam width (21) of the 2D laser pattern (9) is automatically identified and an optical power measurement is carried out at the location of this beam width minimum with the optical measuring device (7), preferably automatically, in order to verify the laser class of the laser module (2), - preferably wherein the verification is automated by a controller (14) of the laser class testing device (1) - a ratio P max / B HS from a laser power P max in the hotspot and a local beamwidth (22) B HS and / or - a ratio P SM / B min from a laser power P SM at the location of the beam width minimum and the local beam width minimum B min calculated and taken into account. [16] Method according to the preceding claim, wherein an accommodation optics (12) of the measuring device (7) is automatically detuned within the scope of the beam profile measurement, - preferably and thus several beam profile measurements are carried out at different accommodation states of the accommodation optics (12) and / or - whereby in this way a minimum B min (B HS ) a / the local beam width (21) in the hotspot is determined and / or - whereby, within the scope of the beam profile measurement, at least two different local beam widths (B HS,x , B HS,y ) in the hotspot. [17] Method according to claim 15 or 16, wherein in the optical scanning - the recording (3), at least temporarily or permanently, remains static in space, while the optical measuring device (7) is moved automatically relative to the static laser module (2) and / or - the measuring device (7) remains static in the room at least temporarily, while the laser module (2) is automatically moved relative to the measuring device (7) in the room. [18] Method according to one of claims 15 to 17, - wherein the hotspot is determined on the basis of light power values recorded by a light power measuring unit (10) of the laser class testing device (1), - preferably wherein for this purpose the 2D laser pattern (9) / the laser line (8) is automatically scanned along at least one scanning direction (20) by means of a first relative movement between the light power measuring unit (10) and the laser module (2) and a laser light power is measured continuously or at regular intervals with the light power measuring unit (10), - in particular so that a continuous laser light power curve along the scanning direction (20) is automatically recorded. [19] Method according to one of claims 15 to 18, - wherein during the beam profile measurement a sensor (11) of the measuring device (7) - automatically placed in the beam path of the laser module (2) and / or - is automatically positioned relative to the 2D laser pattern (9) to be measured by means of a second relative movement between the 2D sensor (11) and the laser module (2), in particular wherein the second relative movement is achieved by pivoting the laser module (2), - preferably in order to determine a respective local beam width (21), in particular a local beam diameter or a local line width, of the 2D laser pattern (9) / the laser line (8) at different locations of the 2D laser pattern (9) / the laser line (8). [20] Method according to one of claims 15 to 19, - during the beam profile measurement, the holder (3) and thus the laser module (2) inserted therein are automatically pivoted about a y-swivel axis, - preferably wherein the y-pivot axis is orthogonal to the z-beam propagation direction of the laser beam (4). [21] Method according to one of claims 15 to 20, - wherein the at least one relative movement between the optical measuring device (7) and the laser module (2), - in particular the first relative movement between the light power measuring unit (10) and the laser module (2) and / or - the second relative movement between the sensor (11) and the laser module (2) is carried out by means of a pneumatic actuator (19), - preferably wherein the pneumatic actuator (19) moves the measuring device (7) and / or the holder (3) in space.

Images