Device and method for determining focal position

Abstract

The present invention relates to a beam analysis apparatus (10) for determining the axial position of the focal point (71) of an energy beam or a sample beam (70) decoupled from an energy beam, comprising a beam shaping device (12), a detector (40), and an analysis device (45). The beam shaping device (12) is decoupled to release two sub-beams (72, 73) from the sample beam (70) on a plane (19) of the sub-beam release process. The cross-sections of the two sub-beams (72, 73) are defined by sub-apertures (32, 33) that are spaced apart from each other and arranged at a distance k in a first transverse direction (31). A beam shaping device (12) is designed to image two sub-beams (72, 73) to form two beam points (92, 93) on a detector, and to deflect at least one of the two sub-beams (72, 73) in a second lateral direction (37) aligned laterally with the first lateral direction (31) to form a distance w between the two beam points (92, 93) along the second lateral direction (37). An evaluation device (45) is designed to determine the distance a between the two beam points (92, 93) on the detector (40) in the first lateral direction (31), and to determine the axial position of the beam focus (71) based on the distance a and / or to determine the change in the axial position of the beam focus (71) based on the change in the distance a. The invention also relates to a corresponding method for determining the axial position of the beam focus (71).

Description

Invention Field

[0001] This invention relates to an apparatus and method for determining the axial position of the focal point of an energy beam of electromagnetic radiation, and more particularly to an apparatus and method for determining the axial position of the focal point of a beam used to process an optical device. Specifically, the energy beam may be a laser beam. The invention also provides an apparatus and method for determining the position of the focal point of a beam used to process an optical device during laser processing operations. Background Technology

[0002] The central focus in laser material processing is the adjustment and control of the axial focal position of the laser beam relative to the material or workpiece. With optimal process control, the laser beam focal point does not necessarily have to be directly on the workpiece surface. Instead, the optimal positioning of the laser beam focal point relative to the workpiece depends on several factors. For example, the focal point can be located within the workpiece, that is, below the workpiece surface, especially when processing workpieces with high material thickness. Typically, the processing result is sensitive to the exact focal position of the laser beam, which is why the position of the laser beam focal point relative to the workpiece is expected or must remain unchanged during processing.

[0003] In laser cutting, the flow dynamics of the cutting gas have a significant impact on the cutting results; therefore, maintaining a constant distance between the workpiece and the cutting nozzle as much as possible during processing is crucial. This problem can be solved using existing technologies, such as capacitive distance measurement and closed-loop control.

[0004] Typically, the problem of changing the position of the beam focus relative to the workpiece is not detecting or tracking the workpiece position or the workpiece distance relative to the processing optics, but rather detecting the actual position of the beam focus relative to the processing optics.

[0005] Modern laser processing systems use lasers with high brightness and power, typically in the kilowatt range. Due to the material properties of the optical components being processed, the high laser power causes the components to heat up. This creates a radial temperature gradient within the optical component due to the temperature dependence of material parameters such as refractive index, resulting in a change in the refractive power of the optical component. This effect is called thermal focal shift. Although this thermal focal shift can be minimized by selecting appropriate optical component materials (e.g., by using high-purity, low-absorption quartz glass), it is almost always present. Reaction products and particles of various sizes generated during laser material processing enhance this effect; these products and particles can deposit on or on the protective glass of the processed optics, leading to increased absorption. Therefore, in particular, the protective glass often helps to alter the beam focus position of the processed optics.

[0006] Devices for determining workpiece distance or workpiece surface position are known in the prior art; these devices operate, for example, based on the fundamental principles of optical triangulation.

[0007] For example, patent application EP0248479A1 discloses an apparatus for optically measuring the distance between a surface and a reference surface. To this end, the surface is illuminated with a radiation source, and after the reflected radiation has passed through a screen having two off-axis openings, the reflected radiation is guided to a detector by an optical system. The range of the beam dot pattern produced by the screen is a measure of the distance between the surface and the reference surface.

[0008] Patent application DE10142206A1 describes a measuring device for determining the depth of a hole or slot formed in the surface of a substrate. Similar to the previously cited patent, light emitted from a light-emitting point on the substrate surface is also used to obtain depth information. The light passes through two openings in an optical screen to a focusing element and is then directed to a detector. Prior to this, light from at least one opening in the screen is directed to a refractive or reflective optical element to change the beam direction. This allows, for example, the amplification of a deflection effect dependent on the depth of the substrate surface.

[0009] Patent application DE102013210078A1 discloses an apparatus and method for determining the focal position of an energy beam. Among other things, the apparatus includes an image acquisition device and an imaging optics unit. The image acquisition device is designed to form at least two observation beams, and the imaging optics unit is used to generate at least two images of an area to be monitored or a reference profile. On one hand, a change in the lateral distance between the two images of the area to be monitored on the workpiece surface can be used to infer the deviation of the focal position relative to the workpiece. On the other hand, a change in the focal length of the focusing element can be determined based on a change in the lateral distance between the two images of a reference structure, which can be formed by, for example, the internal profile of a laser processing nozzle, thus allowing the inference of the change in the focal position. Since light emitted or reflected by the workpiece or reference structure is also used to generate images in this apparatus, the focal position of the energy beam cannot be measured in a strictly defined sense. Changes in the beam focal position are not caused by the focusing element, but rather by, for example, collimating optics, and cannot be determined using the disclosed apparatus.

[0010] Patent application EP2886239A1 discloses a method and apparatus for monitoring and controlling the processing path during laser bonding. The processing head described in this published patent, among other things, has a distance sensor in the form of a double-slit sensor with an imaging device and a double-slit screen. The distance sensor can be used to determine the distance between the processing head and the workpiece surface.

[0011] In all the published patents cited above, the position or distance to the workpiece surface is ultimately determined optically. On the other hand, the aforementioned devices and methods cannot determine the focal position of the light beam pointing onto the workpiece surface, or can only determine it with low precision. To determine the actual focal position of the machining beam, it is necessary to directly measure the machining beam, or to decouple a sample beam from the machining beam and measure the sample beam.

[0012] The apparatus and method for processing materials using electromagnetic radiation are known from published patent WO2012 / 041351A1. A device for generating patterns (e.g., shadow masks) is envisioned here, rotated into an electromagnetic beam focused on the material. A partially reflective surface is arranged in front of the focal point such that an image of the pattern generated by a pattern generator is reflected back from the partially reflective surface and reaches a detector via a beam splitter. The image on the detector is processed by a computer, generating an electrical signal dependent on the focal point position. The disclosed method is intended for use in ophthalmic surgery. However, this method is not suitable or is less suitable for general applications in laser material processing because it is generally not possible to permanently arrange the partially reflective surface directly in front of the beam focal point, and furthermore, arranging a shadow mask in a high-power laser beam is disadvantageous.

[0013] In the apparatus for monitoring a laser beam disclosed in WO2015 / 185152A1, radiation is reflected back by a plate arranged at an angle within the laser beam and detected by a spatially resolved detector. Changes in laser beam divergence can be determined by detecting the shift in the focal position of the sub-beam imaged on the detector. This apparatus is particularly useful for analyzing and monitoring driver laser devices used to generate EUV radiation.

[0014] Patent application DE102011007176A1 describes an apparatus for focusing a laser beam and a method for monitoring laser processing. For this purpose, laser radiation is reflected back from a transmission optical element, particularly from a protective glass, and the reflected radiation is detected by a detector to determine the focal position. The protective glass is arranged at an angle so that the reflected radiation is directly deflected to the side, eliminating the need for further beam separation. A screen is provided to shield the radiation reflected from one side of the protective glass. The focal position of the laser beam is determined by evaluating the size or diameter of the incident area of ​​the reflected laser radiation on the detector.

[0015] Patent DE102013227031A1 discloses an apparatus and method for analyzing a light beam incident on a substrate and for correcting focal length shift. In the disclosed apparatus, a component of the light beam reflected by a protective glass is deflected into a measurement beam path on a sensor for beam analysis. The component reflected from the protective glass is guided through a screen in the measurement beam path, thereby masking interference beams reflected from other parts of the apparatus. To achieve the desired interference beam masking, the protective glass is tilted and / or a wedge is used to deflect the reflected beam. As a sensor, the published patent indicates the use of a CCD camera or a CMOS camera, which can be used for measurement according to DIN ISO 11146. Furthermore, it is envisioned that the actual focal length is determined by calculation using an ABCD matrix.

[0016] The apparatus and method for determining the focal position of a laser beam in a laser processing system, as disclosed in patent application DE102018105364A1, operate in a manner very similar to the apparatus in DE102011007176A1. In the method of DE2018105364A1, it is envisioned that calibration data, including a beam diameter measured as a function of laser power, is used to determine the focal position. Therefore, the determination of the focal position is also based on the method described herein, which is based on determining the diameter of the intensity distribution on the detector.

[0017] In recently cited published patents, the focal position is typically determined by measuring the size or diameter of the beam spot on the detector. While this method can theoretically determine the focal position if the beam parameters are known, it is disadvantageous for several reasons: firstly, the detected beam diameter also changes with the divergence and / or diameter of the processing laser beam; secondly, particularly in the beam waist region, the change in diameter has minimal impact on the focal position. Both of these factors contribute to considerable uncertainty in determining the axial focal position. Finally, based on measurements of the optimal focal position, it is impossible to detect in which direction the beam focal point shifts, since the diameter increases in both directions.

[0018] Later-published patent DE102019004337A1 discloses a beam analysis apparatus for determining the focal position of a beam. It includes an imaging device, a detector unit with a spatially resolved photosensitive detector, and an evaluation unit. Four selection devices generate four sub-beams from a measurement beam. The first and second selection devices are arranged at a first distance along the y-direction, extending laterally to the beam direction of the measurement beam. The resulting first and second sub-beams are imaged onto the detector through a sub-aperture lens, and thus deflected in the y-direction. As the focal position changes, the distance between the beam points of the first and second sub-beams changes along the y-direction on the detector. Based on this change in distance, the evaluation unit can determine the change in the focal position. However, in some cases, the first distance can become very small or even zero. Then, the beam points of the first and second sub-beams are no longer distinguishable, and a definitive evaluation cannot be performed. Third and fourth selection devices are arranged at a second distance along the x-direction, which extends laterally to the beam direction of the measurement beam and is perpendicular to the y-direction. The resulting third and fourth sub-beams are imaged onto the detector through a sub-aperture lens, and thus deflected in the x-direction. When the focal position changes, the distance between the beam points of the third and fourth sub-beams changes along the x-direction on the detector. Based on this change in distance, the evaluation unit can determine the change in the focal position. In some cases, the second distance can also become very small or even zero. Then, the beam points of the third and fourth sub-beams can no longer be distinguished. Summary of the Invention

[0019] Therefore, the object of the present invention is to advantageously develop the principles of optical triangulation, and in particular, to enable it to measure the focal position of a laser beam guided in laser processing optics without resorting to radiation emitted or reflected by the workpiece, thereby enabling particularly precise determination of the focal position. The object of the present invention also is to provide particularly robust, accurate, versatile, and compact apparatus and methods for determining the focal position, and, where applicable, for determining other beam parameters.

[0020] This purpose is achieved through the features listed in this article.

[0021] According to the present invention, a beam analysis apparatus for determining the axial position of a beam focal point is provided, comprising a beam shaping device, a detector, and an evaluation device. Here, the beam focal point is either the focal point of an energy beam of electromagnetic radiation or the focal point of a sample beam decoupled from the energy beam.

[0022] The beam shaping device is configured to release (at least) two sub-beams from an energy beam or from a sample beam decoupled from the energy beam, in a plane of release, wherein the two sub-beams are a first sub-beam and a second sub-beam. The cross-sections of the two sub-beams in the plane of release are defined by corresponding sub-apertures. The sub-apertures are separated from each other. The center points of the sub-apertures are spaced apart by a distance k, wherein a first lateral direction is defined by the distance k between the sub-apertures. The term "lateral" refers to a direction in a plane perpendicular to the respective local optical axis. The beam shaping device is also configured to shape an intensity distribution having (at least two) beam points on a detector, and to image the two sub-beams onto the detector by forming at least one beam point from each of the two sub-beams (i.e., from at least one beam point from the first sub-beam and at least one beam point from the second sub-beam), and to deflect and / or offset at least one of the two sub-beams in a second lateral direction, thereby forming a distance w between the beam points on the detector along the second lateral direction. Here, the second lateral direction is oriented laterally to the first lateral direction, and the two beam points are at least one beam point of the first sub-beam and at least one beam point of the second sub-beam.

[0023] The detector includes a light-sensitive, two-dimensional spatially resolved sensor configured to convert the intensity distribution incident on the detector into an electrical signal. The detector is positioned at a distance s behind the sub-beam release plane along the propagation paths of the two sub-beams.

[0024] The evaluation device is configured to process electrical signals from the detector, representing the intensity distribution on the detector. Furthermore, the evaluation device is configured to determine a distance 'a' between the positions of two beam points on the detector along a first lateral direction. Additionally, the evaluation device is configured to determine the axial position of the beam focal point based on distance 'a', and / or to determine a change in the axial position of the beam focal point based on a change in distance 'a'.

[0025] A beam analyzer is a particularly robust, accurate, versatile, and compact device for determining the location of a focal point.

[0026] In other words, the beam shaping device is configured to form (at least two) sub-apers in the plane of the sub-beam releaser for releasing a corresponding one of the two sub-beams. In other words, the beam shaping device is configured such that the beam point of one sub-beam and the beam point of the other sub-beam form a distance 'a' between them, with the distance 'k' on the detector along a first lateral direction (in the first lateral direction of the sub-beam release plane) forming a distance 'a' between them along the first lateral direction on the detector, wherein, among other things, distance 'a' depends on the axial position of the beam focus.

[0027] Furthermore, in other words, the beam shaping device is configured such that the beam point of one sub-beam and the beam point of the other sub-beam at the detector are additionally displaced by a distance w relative to each other along a second lateral direction at the detector, due to the deflection and / or displacement of at least one of the two sub-beams, wherein the second lateral direction at the detector is transverse to the first lateral direction at the detector. In some cases, the first distance a can become very small or even zero. Due to the additional distance w between the two beam points at the detector, the two beam points are still distinguishable even in this case. For example, the beam shaping device can be configured such that the distance w is so large that even when the distance a becomes zero, the two beam points only partially overlap (or preferably do not overlap at all).

[0028] The beam analysis apparatus according to the invention may also be optionally improved by one or more of the features listed below.

[0029] The sample bundle can be the same as the energy bundle, especially if the sample bundle is not formed by decoupling from the energy bundle.

[0030] To receive electrical signals from the detector, the evaluation device can be connected to the detector. For example, the evaluation device can be connected to the detector via at least one data line. Optionally or additionally, the evaluation device can be wirelessly connected to the detector to receive electrical signals from the detector. According to another aspect of the invention, the evaluation device and the detector can be designed as a common unit.

[0031] For example, the first lateral direction and the local optical axis between the sub-beam release plane and the detector can be altered in the beam analyzer by beam folding and / or beam redirection. Furthermore, the second lateral direction can be correspondingly altered by beam folding and / or beam redirection. Beam folding and / or beam redirection allow for a more compact beam analyzer, for example, without compromising measurement accuracy.

[0032] The beam shaping device of the beam analysis apparatus can be configured to deflect and / or offset two sub-beams relative to each other, wherein the difference between the deflection and / or offset of the two sub-beams along the second lateral direction is aligned to form a distance w along the second lateral direction between the two beam points on the detector. Specifically, the beam shaping device can be configured to deflect and / or offset the two sub-beams along the second lateral direction, wherein only the difference between the deflection and / or offset of the two sub-beams along the second lateral direction results in the formation of the distance w. This allows for the achievement of a large distance w with minimal impact on the optical axis.

[0033] The beam analysis apparatus may include a decoupling device, wherein the decoupling device includes a beam decoupler for decoupling the sample beam from the energy beam. In this way, beam analysis can be readily applied to existing processing optics. Furthermore, the decoupling device allows measurements to be performed by the beam analysis apparatus during normal operation of the processing optics.

[0034] The beam decoupler of a beam analysis apparatus can be a beam splitter device, configured to decouple the radiation components of the energy beam, ranging from 0.01% to 5%, as a sample beam through reflection and / or transmission. In typical applications, this beam component is sufficient for accurate measurements on the one hand, and the energy beam is significantly attenuated only by decoupling on the other.

[0035] The beam shaping device of the beam analysis apparatus may include an imaging device with at least one optical lens for imaging the sub-beam onto a detector. This, for example, allows for the use of a more compact detector. Optionally or additionally, this can improve measurement accuracy.

[0036] A sub-beam release plane can be set at the image-side focal point (also known as the second focal point) of the imaging device. This makes evaluation particularly easy.

[0037] The evaluation device is configured to determine the axial position of the beam focal point based on the distance 'a' between the two beam points using a linear calculation rule, and / or to determine the change in the axial position of the beam focal point based on the change in the distance 'a' between the two beam points. This enables particularly simple, accurate, and rapid evaluation with minimal computational effort.

[0038] The evaluation device is configured to determine the axial position of the beam focal point based on the distance 'a' between the two beam points using at least a partially linear calculation rule, and / or to determine the change in the axial position of the beam focal point based on the change in the distance 'a' between the two beam points. This allows for simple, accurate, and rapid evaluation with minimal computational effort.

[0039] The beam analysis apparatus may include a beam folding device comprising a beam splitter and at least one reflector, and is arranged in the beam path in front of the detector. The at least one reflector is arranged to reflect components of the beam leaving the beam splitter back into the beam splitter, wherein the beam folding device forms a first folded beam path in such a way that the sub-beam release plane of the beam shaping device is arranged in the beam path in front of the beam folding device or in the first folded beam path. Beam folding allows for a more compact design of the beam analysis apparatus without compromising measurement accuracy.

[0040] In another improvement to the beam analysis apparatus, the beam folding device may further include at least one second mirror, wherein the second mirror is arranged to reflect another radiation component leaving the beam splitter back into the beam splitter, wherein the beam folding device forms a second folded beam path in such a way that, for example, other parameters can be measured.

[0041] In a possible variation of the embodiment of the beam analysis apparatus, it is envisioned that the sub-beam release plane of the beam shaping device is arranged in the first folded beam path, and no sub-beam release is arranged in the second folded beam path. In this way, the radiation component of the sample beam (or energy beam) is guided as an unmodulated beam to the detector via the second folded beam path. Here, the evaluation apparatus can be configured to determine the beam diameter and / or beam profile based on the intensity distribution of the beam spot of the unmodulated beam on the detector. This allows for more accurate characterization of the energy beam or sample beam.

[0042] In the second folded beam path, the reflector can be arranged such that it can be axially displaced, and the position of the reflector can be adjusted by a positioning device. The axial displacement of the second reflector can be used, for example, to determine the beam caustics (i.e., the beam envelope) of the energy beam or sample beam. An evaluation device can be accordingly configured to determine the beam caustics. In particular, the evaluation device can be configured to control the axial displacement of the reflector.

[0043] The beam shaping device of the beam analysis apparatus may include a beam splitter device having at least one sub-beam deflection element to form a distance w along the second lateral direction between the two beam points on the detector.

[0044] The beam splitter device may further include at least two sub-beam deflection elements for deflecting and / or shifting the two sub-beams relative to each other. Here, the difference between the deflection and / or shift of the two sub-beams is aligned along the second lateral direction to form a distance w along the second lateral direction between the two beam points on the detector.

[0045] The beam splitter device may include at least one wedge plate as a sub-beam deflection element, which is arranged in front of or behind one of the sub-apertures in the beam direction and is configured to deflect one of the two sub-beams released from the sub-aperture by an angle ranging from 0.02° to 6°.

[0046] The beam splitter device may include at least one inclined plate or prism as a sub-beam deflection element, which is arranged in front of or behind one of the sub-apertures in the beam direction and is configured to shift one of the two sub-beams released from the sub-aperture by an amount ranging from 0.05 mm to 3 mm.

[0047] The beam splitter device can be arranged within the first folded beam path and can include at least two mirrors as sub-beam deflection elements. Each of the at least two mirrors can be aligned in front of or behind one of the sub-apertures in the beam direction; optionally, the periphery or edge of the mirror itself can form the sub-aperture. Each of the two mirrors is configured to reflect back to one of the two sub-beams. The angular difference between the normal directions on the mirror surfaces is in the range of 0.01° to 3°, and the difference between the normal directions on the mirror surfaces is aligned along a second lateral direction.

[0048] Furthermore, the evaluation device can be configured to determine the lateral position of the entire intensity distribution on the detector having (at least) two beam points, and can be configured to:

[0049] ● Used to calculate the lateral position of the sample beam focal point from the lateral position of the entire intensity distribution.

[0050] / or

[0051] ● Used to calculate the change in the lateral position of the beam focal point of the sample beam from the change in lateral position across the entire intensity distribution.

[0052] In possible variations of the embodiment, the beam analysis apparatus may include a beam splitter for separating the sample beam, another imaging device having at least one optical lens, and a second detector. Here, the beam splitter is disposed in the beam path in front of the sub-beam release plane of the beam shaping apparatus, and the beam splitter is positioned between the optical lens of the imaging device and the sub-beam release plane.

[0053] In a possible variation of this embodiment, the other imaging device is arranged between the beam splitter and the second detector to image a magnified beam spot or magnified image of the beam focal point onto the second detector. This allows for more accurate characterization of the energy beam or sample beam.

[0054] The evaluation device can be configured to process the electrical signal generated by the second detector, and the evaluation device can be configured to determine the beam diameter and / or focal diameter based on the intensity distribution on the second detector.

[0055] In another possible variation of the embodiment, the beam analysis apparatus may include a beam splitter for separating the sample beam, another imaging device having at least one optical lens, and a second detector. In this case, the beam splitter is arranged in the beam path in front of the sub-beam release plane of the beam shaping device, and the beam splitter is positioned between the optical lens of the imaging device and the sub-beam release plane. The other imaging device is arranged between the beam splitter and the second detector. The imaging device and the other imaging device together form a combined lens system having a focal plane on the image side. The second detector may be arranged in the image-side focal plane (also referred to as the second focal plane) of the combined lens system.

[0056] The evaluation device can be configured to process the electrical signal generated by the second detector, and the evaluation device can be configured to determine the divergence angle based on the intensity distribution on the second detector.

[0057] In a possible variation of the embodiment, the beam shaping device is configured such that when the axial position of the beam focal point changes, the positions of the two beam points on the detector extend along two paths separated by a distance w from each other.

[0058] Furthermore, a system can be provided that includes a beam analysis device for guiding and focusing an energy beam and processing optics. The processing optics may include a decoupling device for decoupling the sample beam from the energy beam. Additionally, the beam analysis device can be connected to the processing optics for receiving the decoupled sample beam. The beam analysis device can therefore be used in a simple manner to test the energy beam.

[0059] To achieve the objectives of this invention, a beam analysis method for determining the axial position of a beam focal point is also provided. Here, the beam focal point is the focal point of an energy beam of electromagnetic radiation or the focal point of a sample beam decoupled from the energy beam. The method includes at least the following steps:

[0060] - In the sub-beam release plane, at least two sub-beams are released from the energy beam or from a sample beam decoupled from the energy beam, for example by a beam shaping device, wherein the two sub-beams are a first sub-beam and a second sub-beam, and wherein the cross-sections of the two sub-beams in the sub-beam release plane are defined by corresponding sub-apertures. The sub-apertures are spaced apart from each other, and the center points of the sub-apertures are at a distance k from each other. The distance k between the sub-apertures defines a first lateral direction. The term "lateral" refers to a direction in a plane perpendicular to the corresponding local optical axis.

[0061] -Guiding the two sub-beams onto a detector positioned at a distance s behind the sub-beam release plane along the propagation path of the two sub-beams, wherein guiding the two sub-beams onto the detector comprises the following sub-steps:

[0062] ● Image the two sub-beams onto a detector, for example, using a beam shaping device, to form at least one beam point from each of the two sub-beams (that is, at least one beam point from the first sub-beam and at least one beam point from the second sub-beam), so as to form an intensity distribution on the detector having two beam points, wherein the two beam points are at least one beam point from the first sub-beam and at least one beam point from the second sub-beam, respectively.

[0063] ● At least one of the two sub-beams is deflected and / or shifted in the second lateral direction, for example by a beam shaping device, thereby forming a distance w in the second lateral direction between the two beam points on the detector, wherein the second lateral direction is perpendicularly aligned with the first lateral direction.

[0064] - The intensity distribution illuminating the detector is converted into an electrical signal by a two-dimensional spatially resolved sensor that is sensitive to light radiation.

[0065] - The electrical signal of the detector, representing the intensity distribution on the detector, is processed, for example by an evaluation device.

[0066] - Determine the distance 'a' between the positions of the two beam points along the first lateral direction, for example, through the evaluation device.

[0067] - Determine the axial position of the beam focal point based on distance a, or determine the change in the axial position of the beam focal point based on the change in distance a.

[0068] The beam shaping apparatus can be designed in any form according to the described embodiments. The advantages described herein apply accordingly to the beam analysis method.

[0069] In particular, the evaluation apparatus can be designed according to any form of the embodiments described herein. The advantages described herein apply accordingly to the beam analysis method.

[0070] The beam analysis method according to the present invention can also be represented by one or more optional steps listed below.

[0071] The two sub-beams may be deflected and / or offset relative to each other, for example by the beam shaping device, wherein the difference between the deflection and / or offset of the two sub-beams is aligned along the second lateral direction, thereby forming a distance w along the second lateral direction between the two beam points on the detector.

[0072] Specifically, two of the two sub-beams can be deflected and / or offset in the second lateral direction, so that only the difference between the deflection and / or offset of the two sub-beams in the second lateral direction results in the formation of distance w. This makes it possible to achieve a large distance w with minimal impact on the optical axis.

[0073] In another step, the sample beam can be decoupled from the energy beam, for example, by a beam decoupler in a decoupling device.

[0074] As a sample beam, the radiation components of the energy beam in the range of 0.01% to 5% can be decoupled by reflection and / or transmission, for example, by a beam decoupler.

[0075] Imaging of the two sub-beams onto the detector can be accomplished by an imaging device having at least one optical lens arranged in the beam shaping device.

[0076] The release of the sub-beam can occur in the plane located at the image-side focal point of the imaging device.

[0077] Determining the axial position of the beam focal point based on the distance 'a' between two beam points, or determining the change in the axial position of the beam focal point based on the change in the distance 'a' between the two beam points, can be performed using linear calculation rules.

[0078] Determining the axial position of the beam focal point based on the distance 'a' between two beam points, or determining the change in the axial position of the beam focal point based on the change in the distance 'a' between the two beam points, can be performed using at least partially linear calculation rules.

[0079] In another step, a first folded beam path can be formed by a beam folding device, which includes a beam splitter and at least one reflector, and is arranged in the beam path in front of the detector to reflect the beam component leaving the beam splitter back into the beam splitter. Here, the release of the two sub-beams can occur in the beam path in front of the beam folding device or in the first folded beam path.

[0080] In another step, by further including a beam folding device with at least one second reflector, a second folded beam path can be formed by reflecting another radiation component leaving the beam splitter back into the beam splitter at the second reflector.

[0081] An alternative method is also envisioned, in which the release of two sub-beams occurs in the first folded beam path, and no sub-beam release occurs in the second folded beam path, so that the radiation component of the sample beam (or energy beam) is guided onto the detector as an unmodulated beam. Here, for example, by the evaluation apparatus, the beam diameter and / or beam profile can be determined based on the intensity distribution of the beam point of the unmodulated beam on the detector.

[0082] In another alternative method, the axial position of the reflector in the second beam path can be changed by a positioning device, and for each of at least three different positions of the reflector, the intensity distribution of the beam spot of the unmodulated beam can be recorded on the detector. At least one beam parameter of the unmodulated beam can be determined based on the recorded intensity distribution, for example, by the evaluation device.

[0083] In another step, the lateral position of the entire intensity distribution with two beam points on the detector can be determined, and the lateral position of the beam focus of the sample beam can be calculated from the lateral position of the entire intensity distribution, or the change in the lateral position of the beam focus of the sample beam can be calculated from the change in the lateral position of the entire intensity distribution.

[0084] Another possible approach may include the following three steps:

[0085] - The sample beam is separated by a beam splitter located behind the optical lens of the imaging device in the beam path and in front of the sub-beam release plane.

[0086] - The separated sample beam is imaged onto a second detector by another imaging device, the other imaging device including at least one optical lens arranged between the beam splitter and the second detector for forming a magnified image of the beam spot or beam focus on the second detector.

[0087] - Determine the beam diameter or focal diameter based on the intensity distribution on the second detector.

[0088] Another possible approach could include the following three steps:

[0089] - The sample beam is separated by a beam splitter located behind the optical lens of the imaging device in the beam path and in front of the sub-beam release plane.

[0090] A separate sample beam is guided to a second detector via another imaging device, which has at least one optical lens disposed between the beam splitter and the second detector for forming a far-field beam distribution on the second detector. Here, the imaging device and the other imaging device together form a combined lens system with an image-side focal plane. The second detector is disposed in the image-side focal plane of the combined lens system.

[0091] - Determine the far-field beam diameter or divergence angle based on the intensity distribution on the second detector.

[0092] Alternatively, a method could be envisioned in which the energy beam is focused by manipulating optics.

[0093] Alternatively, another approach can be envisioned, in which the axial position of the determined beam focal point or a change in the axial position of the determined beam focal point is used to control the laser processing operation.

[0094] Optionally, a method is provided in which, when the axial position of the beam focus changes, the positions of two beam points on the detector extend along two paths separated by a distance w. Attached Figure Description

[0095] The invention is illustrated in more detail with reference to the following accompanying drawings, but is not limited to the embodiments and forms of the embodiments shown. Rather, forms of embodiments are also contemplated, in which elements and aspects can be combined as shown in the various drawings. Here:

[0096] Figure 1a : A schematic diagram of an embodiment of the beam analysis apparatus according to the present invention is shown.

[0097] Figure 1b It shows something similar to Figure 1a A schematic diagram of an embodiment of a beam analysis device with an additional decoupling device.

[0098] Figure 2 A schematic diagram of a modulation device for a beam analysis apparatus is shown, along with a schematic diagram of an exemplary intensity distribution in front of and behind the modulation device.

[0099] Figure 3 A schematic example diagram of the beam spot on the detector of the beam analysis device and a schematic diagram of the intensity distribution on the detector are shown.

[0100] Figure 4 :shown as Figure 1a The schematic diagram of the beam analysis apparatus shown includes an additional illustration of the beam path with varying focal positions.

[0101] Figure 5A schematic example diagram of a beam spot on a detector is shown, with additional illustrations showing the change in the position of the beam spot as the focus position changes.

[0102] Figure 6 A schematic, incomplete illustration of a beam analysis apparatus is shown, in which the modulation device is arranged in front of the imaging device. Only those elements essential for determining the focal position are shown.

[0103] Figure 7 This is a schematic, incomplete illustration of a beam analysis apparatus, with the modulation device located behind the imaging apparatus. Only those elements crucial for determining the focal point are shown.

[0104] Figure 8 The diagram shows a variation of an embodiment of the beam analysis apparatus, wherein the modulation device is arranged in the focal plane of the imaging apparatus.

[0105] Figure 9 The diagram illustrates a variation of an embodiment of the beam analysis apparatus, in which the imaging apparatus and the beam splitter apparatus are implemented in a common arrangement.

[0106] Figure 10 This diagram illustrates another embodiment of a beam analysis apparatus with a beam folding device.

[0107] Figure 11a This diagram illustrates a form of another embodiment of a beam analysis apparatus having an arrangement of beam splitter devices in a folded beam path.

[0108] Figure 11b The diagram shows a schematic representation of another embodiment of the beam analysis apparatus, which has an arrangement of beam splitter devices in a folded beam path and uses an alternative beam splitter.

[0109] Figure 12 The diagram shows a schematic representation of another embodiment of a beam analyzer, in which modulation devices and beam splitter devices are arranged in a folded beam path.

[0110] Figure 13 The diagram shows a schematic representation of another embodiment of the beam analysis apparatus, in which the modulation device and the beam splitter device are implemented in a common arrangement.

[0111] Figure 14 The diagram shows a schematic representation of another embodiment of the beam analysis apparatus, which has a beam folding device for forming two different beam paths onto the detector.

[0112] Figure 15aA schematic example illustration of a beam point on a detector of a variant of an embodiment of a beam analysis apparatus having two beam paths is shown.

[0113] Figure 15b A schematic example illustration of a beam point on a detector of a variant of an embodiment of a beam analysis apparatus having two beam paths is shown, with additional illustrations showing the change in the position of the beam point as the focal position changes.

[0114] Figure 16a This diagram illustrates another embodiment of a beam analysis device having two beam paths to the detector and an additional shutter device.

[0115] Figure 16b It shows something similar to Figure 16a A schematic diagram of another variation of an embodiment of a beam analysis device with an additional decoupling device.

[0116] Figure 16c It shows something similar to Figure 16a A schematic diagram of another variation of an embodiment of a beam analysis device with additional decoupling devices and additional beam power measurement.

[0117] Figure 16d It shows something similar to Figure 16c A schematic diagram of another variation of an embodiment of a beam analysis device with a multi-stage decoupling mechanism.

[0118] Figure 17 The diagram illustrates another form of an embodiment of a beam analysis apparatus having two beam paths to the detector, wherein the modulation device is arranged in only one beam path.

[0119] Figure 18 : A schematic diagram of another form of an embodiment of a beam analysis apparatus having two beam paths to a detector is shown, wherein the modulation device is arranged in only one beam path and wherein the unmodulated beam is magnified and imaged onto the detector.

[0120] Figure 19a It shows something similar to Figure 17 A schematic diagram of another variation of an embodiment of the beam analysis device, wherein the beam path length of the unmodulated beam is adjustable.

[0121] Figure 19b It shows something similar to Figure 19a A schematic diagram of another embodiment of a beam analysis device with an additional decoupling device.

[0122] Figure 19c It shows something similar to Figure 19aA schematic diagram of another form of an embodiment of a beam analysis device having an additional decoupling device and an additional beam power measurement device.

[0123] Figure 19d It shows something similar to Figure 19a A schematic diagram of another embodiment of a beam analysis apparatus combined with processing optics, wherein the sample beam is decoupled from the collimated energy beam of the processing optics.

[0124] Figure 19e It shows something similar to Figure 19a Another schematic diagram of an embodiment of a beam analysis apparatus combined with processing optics, wherein the sample beam is formed by reflection decoupling of radiation components reflected back from the protective glass.

[0125] Figure 19f It shows something similar to Figure 19a Another schematic diagram of an embodiment of a beam analysis apparatus combined with processing optics, wherein the sample beam is formed by transmission coupling of radiation components reflected back from the protective glass.

[0126] Figure 20 This illustration shows a schematic diagram of another form of an embodiment with an additional beam analysis device for separating and imaging sample beam components onto a second detector.

[0127] Figure 21 This illustration shows a schematic diagram of another form of an embodiment of a beam analysis device having an additional second detector that separates and guides sample beam components to an adjustable beam path length.

[0128] Figure 22 It shows something similar to Figure 14 A schematic diagram of another form of an embodiment of a beam analysis device with two beam paths and additional far-field beam distribution separation and imaging of the sample beam onto a second detector.

[0129] Figure 23 It shows something similar to Figure 18 A schematic diagram of another form of an embodiment of a beam analysis device with two beam paths and additional far-field beam distribution separation and imaging of the sample beam onto a second detector.

[0130] Figure 24 It shows something similar to Figure 19a A schematic diagram of another form of an embodiment of a beam analysis device with two beam paths and additional far-field beam distribution separation and imaging of the sample beam onto a second detector.

[0131] Figure 25The diagram shows a schematic representation of an embodiment of a beam analysis apparatus having a beam shaping device with four sub-apertures for separating (releasing) four sub-beams.

[0132] Figure 26a : Shown according to Figure 25 A schematic diagram of a modulation device and a beam splitter device used in a beam analysis apparatus.

[0133] Figure 26b : Shown according to Figure 25 The detector of the beam analysis device and according to Figure 26a A schematic example illustration of a beam spot on the detector of a modulation device.

[0134] Figure 27a It shows something similar to Figure 25 A schematic diagram of another modulation device and beam splitter device used in a beam analysis apparatus.

[0135] Figure 27b : This shows when using according to Figure 27a A schematic diagram of the modulation device on the detector.

[0136] Figure 28a : A schematic diagram of another modulation device with four sub-holes is shown.

[0137] Figure 28b : This shows when using according to Figure 28a A schematic diagram of the modulation device on the detector.

[0138] Figure 29a It shows something similar to Figure 25 A schematic diagram of another modulation device and beam splitter device for a beam analysis apparatus, but with three sub-apertures.

[0139] Figure 29b : This shows when using according to Figure 29a A schematic diagram of the modulation device on the detector.

[0140] Figure 30a : A schematic diagram of another modulation device with four sub-apers and a beam splitter device for deflecting the four sub-beams is shown.

[0141] Figure 30b : This shows when using according to Figure 30a A schematic diagram of the modulation device on the detector.

[0142] Detailed description of the attached figures

[0143] Figure 1aA beam analysis apparatus 10 according to the invention is shown, comprising a beam shaping device 12, a detector 40, and an evaluation device 45. Preferably, the beam shaping device 12, the detector 40, and the evaluation device 45 are arranged together in a housing. The beam analysis apparatus 10 receives a sample beam 70 propagating along an optical axis 11, having a beam focal point 71. The beam shaping device 12 includes a modulation device 20, a beam splitter device 52, and an imaging device 50, which, in this example, are designed as separate devices. The modulation device 20 is used to separate two sub-beams 72, 73 from the sample beam 70 in a sub-beam release plane 19. For this purpose, the modulation device 20 has at least two mutually separated transmission regions 21, 22, and at least one blocking region 25, which in each case completely surrounds the transmission regions 21, 22 and separates them from each other. In the regions of the transmission regions 21, 22, radiation propagates forward to the detector 40; in the region of the blocking region 25, radiation is prevented from propagating to the detector. In this way, the edges of the transmission zones 21 and 22 define two sub-apertures 32 and 33, which define the cross-sections of the thus formed sub-beams 72 and 73 in the sub-beam release plane 19. The center points of the sub-apertures 32 and 33 have a distance k between them. This distance k, that is, the imaginary shortest connection between the center points of the sub-apertures 32 and 33, defines a first lateral direction 31. The first lateral direction 31 is perpendicular to the local optical axis 11. Figure 1a In the selected representation, as an example, the first horizontal direction 31 is aligned parallel to the y-axis. Therefore, Figure 1a The upper part shows a diagram of the beam analysis device 10 in the yz plane, as indicated by the coordinate arrows y and z. The modulation device 20 modulates the intensity distribution of the sample beam 70 within the sub-beam release plane 19, thereby forming a shaped sample beam 79 with two sub-beams 72 and 73. For example, the modulation device 20 may be a dual-aperture screen with two openings, wherein the two openings represent transmission regions 21 and 22.

[0144] The shaped sample bundle 79 is imaged onto the detector 40 via the imaging device 50. The detector 40 has a light-sensitive, two-dimensionally resolved sensor in the sensor plane 39, which converts the intensity distribution on the detector 40 into an electrical signal, which is received and processed by the evaluation device 45. In this embodiment, the evaluation device 45 is electrically connected to the detector 40 for this purpose. The imaging device 50 includes at least one optical lens 51. By imaging the shaped sample bundle 79 onto the detector 40, at least one beam point 92, 93 is formed on the detector for each of the sub-beams 72, 73. The two beam points 92, 93 have a distance a between them on the detector 40 in a first lateral direction 31. Among other things, the distance a depends on the distance k between the sub-apertures 32, 33, the distance s between the sub-beam release plane 19 and the sensor plane 39, and the distance z between the axial position of the beam focus 71 and the sub-beam release plane 19. s Therefore, the axial position of the beam focus 71 can be determined from the distance a. If the imaging position of the beam focus 71 falls on the detector 40 or the sensor plane 39, then the distance a is zero. In order for the evaluation device 45 to be able to clearly allocate beam points 92, 93, and thus distinguish the positive and negative displacements of the beam focus 71, that is, forward or backward, according to the invention, at least one of the sub-beams 72, 73 is deflected or offset along a second lateral direction 37, which is oriented laterally to the first lateral direction 31. The second lateral direction 37 may, for example, be perpendicular to the first lateral direction 31. Similar to the first lateral direction 31, the second lateral direction 37 is perpendicular to the local optical axis 11. Figure 1a In the embodiment, both sub-beams 72 and 73 are deflected along the second transverse direction 37. For this purpose, the beam shaping device 12 has a beam splitter device 52, which in this embodiment includes two wedges as sub-beam deflection elements 53 and 54. In each case, one of the wedges 53 and 54 is arranged aligned in the beam direction behind one of the transmission zones 21 and 22. In the example shown, the two sub-beams are thus deflected by approximately the same amount along the second transverse direction 37, but in opposite directions. The deflection direction is defined by the direction of the wedge angle of the wedges. For example, sub-beam 72 can be deflected by wedge 53 by an angle ranging from 0.02° to 6°, and sub-beam 73 can be deflected by wedge 54 by the same angle in the opposite direction. Due to the deflection and propagation toward detector 40, beam points 92 and 93 have a distance w between them in the direction of the second transverse direction 37. To illustrate this deflection, it is shown that... Figure 1a The upper part occurs outside the plane of the diagram, in Figure 1a The lower part shows a partial illustration of the beam analysis device 10 in the xz plane, as indicated by the coordinate arrows x and z at the bottom of the figure.

[0145] Figure 1b It shows something similar to Figure 1a The beam analysis device 10 shown is in the form of the embodiment illustrated. Figure 1b Variations of the embodiment of the beam analysis device 10 shown Figure 1a The difference in the illustrated embodiment lies in the additional decoupling device 14. Decoupling device 14 includes a beam decoupler 15. Through beam decoupler 15, the sample beam 70 is decoupled from the energy beam 77 of electromagnetic radiation (e.g., a laser beam). In this example, beam decoupler 15 is a flat plate arranged as a beam splitter, and at one of its interfaces, a portion of the intensity of the energy beam 77 is reflected as the sample beam 70. To adjust the degree of reflection, the plate can be coated, for example, with a reflection reduction layer. A typical antireflective coating with low residual reflection in the range of about 0.05% to about 1% may be sufficient to provide the sample beam 70. Therefore, decoupling device 14 simultaneously reduces and / or limits the radiation intensity of the sample beam 70. Figure 1b All other features of the middle embodiment correspond to Figure 1a The features shown, the same reference numerals correspond to those shown in the figures. Figure 1a The same characteristics; in this respect, refer to Figure 1a Description of other features.

[0146] Figure 2 It shows that it can be based on Figure 1a An example of the modulation device 20 used in the beam analysis device 10 of 1b. Figure 2 The modulation device 20 shown is a dual-aperture screen. The modulation device 20 has two separate transmission zones 21, 22 and a blocking zone 25 surrounding the transmission zones 21, 22. In this embodiment, the transmission zones 21, 22 are circular openings. No radiation is transmitted in the region of the blocking zone 25; the blocking zone 25 may be composed of an absorptive and / or reflective material. The edges of the transmission zones 21, 22 define two sub-apertures 32, 33. The center points of the sub-apertures 32, 33 define a first lateral direction 31 and are spaced apart by a distance k. In this embodiment, the sub-apertures 32, 33 each have a width b along the first lateral direction 31. A sample beam 70 irradiates the modulation device 20 and has an intensity distribution 81 in front of the modulation device 20, which may be, for example, Gaussian. The radiation propagating through the transmission zones 21, 22 forms a shaped sample beam 79 having two sub-beams 72, 73. Immediately following the modulation device 20, the shaped sample beam 79 has an intensity distribution 82. For the Gaussian sample bundle 70, the intensity distribution 81 of the sample bundle 70 in front of the modulation device 20 and the intensity distribution 82 of the shaped sample bundle 79 immediately following the modulation device 20 are... Figure 2 The right side portion is schematically shown as the beam distribution along the first lateral direction 31.

[0147] Figure 3 It is based on Figure 1a A schematic example illustration of the intensity distribution on detector 40 in beam analysis device 10 of or 1b. The intensity distribution on detector 40 consists of beam points 92, 93, which are focused or approximately focused by imaging device 50. Beam points 92, 93 are spaced apart by a distance a in the first lateral direction 31. In the exemplary distribution of beam points shown, distance a is zero, but can have any value. Distance a changes when the axial position of beam focus 71 changes. By deflecting sub-beams 72, 73 by means of beam splitter device 52, beam points 92, 93 are spaced apart by a distance w in the second lateral direction 37. Distance w does not change with the axial position of beam focus 71. Figure 3 In the right-hand portion, the intensity distribution 83 of the shaped sample beam 79 on the detector 40 is schematically represented as a beam profile along the second transverse direction 37. The two peaks in the beam profile of the represented intensity distribution 83 represent beam points 92 and 93.

[0148] Figure 4 It shows the relationship with Figure 1a The same beam analysis device 10 is used in this context. Reference is made to... Figure 1a To explain Figure 4 . Figure 4 Additionally, the change in distance 'a' between beam points 92 and 93 on detector 40 when the axial position of beam focus 71 changes is shown. To avoid compromising the clarity of the representation, in Figure 4 Sub-beams 72 and 73 are not represented by their edge beams formed at the edges of sub-apertures 32 and 33, but only by their beams passing through the corresponding center points of sub-apertures 32 and 33. The illumination point of the beam passing through the center point of sub-apertures 32 and 33 on the detector 40 represents the position of beam points 92 and 93. Figure 4 The apostrophe reference symbol indicates details changed by the displacement of the beam focus 71. The change in the beam focus position is Δz = z. s -z s The change in the distance between beam points 92 and 93 is Δa = a' - a.

[0149] With Figure 3 In a similar way, Figure 5 It schematically shows the following based on Figure 1a , Figure 1b or Figure 4 The intensity distribution of beam points 92 and 93 on the detector 40 of the beam analysis device 10, the beam analysis device 10 is equipped with such Figure 2 The modulation device 20 shown. Figure 5The change in distance 'a' between beam points 92 and 93 on detector 40 when the axial position of beam focus 71 changes is also illustrated. The apostrophe reference numerals in the figure indicate details altered by the axial displacement of the beam focus. Beam points 92 and 93 are spaced apart by distance 'a' in the first lateral direction 31. For example, when the axial position of beam focus 71 changes, distance 'a' changes to distance 'a''. In the second lateral direction 37, sub-beams 72 and 73 are deflected by beam splitter device 52, and beam points 92 and 93 are spaced apart by distance 'w', which does not change when the axial position of beam focus 71 changes. Distance 'w' is independent of the axial position of beam focus 71. Therefore, when the axial beam focus position changes, the positions of beam points 92 and 93 on detector 40 extend along two paths separated by distance 'w'. Thus, the allocation of beam points is always well-defined, and the magnitude and direction of the change can be clearly determined.

[0150] Figure 6 The geometric quantities and relationships that influence the distance 'a' between beam points 92 and 93 as a function of the axial position of the beam focus 71 are shown; that is, the elements crucial for determining the focus position are represented. Reference numerals 10 and 52 are placed in parentheses because they do not represent all elements of the beam analysis device 10. Otherwise, the beam analysis device 10 shown here corresponds to... Figure 1a The apparatus shown has a modulation device 20 positioned in front of the lens 51 of the imaging device 50 in the beam direction. In the figure, the following geometric quantities are shown using the following defined formula symbols:

[0151] a is the distance between beam points 92 and 93 on detector 40 along the first lateral direction 31;

[0152] a' is the distance along the first lateral direction between beam points 92' and 93' on detector 40 when the beam focal position changes;

[0153] k is the distance between the center points of sub-apertures 32 and 33 within the sub-beam release plane 19, wherein the imaginary line connecting the center points of sub-apertures 32 and 33 defines the first lateral direction 31.

[0154] z s It is the distance between the axial position of the beam focus 71 and the sub-beam release plane 19;

[0155] z s 'is the distance between the axial position of the shift beam focus 71' and the sub-beam release plane 19;

[0156] Δz represents the change in the position of the axial beam focal point, Δz = z s -z s ';

[0157] z0 is the distance from the beam focal point to the sub-beam release plane 19 when the image plane of the beam focal point coincides with the sensor plane 39 of the detector 40 during imaging using the imaging device 50.

[0158] s is the distance between the sub-beam release plane 19 and the sensor plane 39 of the detector 40;

[0159] e is the distance from the sub-beam release plane 19 to the position of the imaging device 50, or more precisely...

[0160] The distance to the main plane of the imaging device 50.

[0161] Figure 7 As shown Figure 6 The geometric quantities and relationships shown determine the functional relationship between the distance 'a' between beam points 92 and 93 and the axial position of beam focus 71. Figure 6 In contrast, the modulation device 20 is positioned behind the lens 51 of the imaging device 50 in the beam direction. A different formula notation is defined for this case:

[0162] d is the distance from the position of the imaging device 50, or more precisely, from the main plane of the imaging device 50 to the sub-beam release plane 19.

[0163] Figure 8 It shows something similar to Figure 1a A variation of the beam analysis device 10 has the following differences: the modulation device 20 is arranged behind the lens 51 of the imaging device 50 in the beam direction; specifically, the distance d from the main plane of the imaging device 50 to the sub-beam release plane 19 is equal to the focal length f, where f is the focal length of the imaging device 50. In other words, the sub-beam release plane 19 is located at the image-side focal point (second focal point) of the imaging device 50. In this arrangement, the change in distance Δa = a' - a, that is, the change in the positional difference between beam points 92 and 93 in the first lateral direction 31 is exactly proportional to the change in the axial beam focal point position Δz. The calculation formula for this situation is:

[0164] Δz=Δaf 2 / (sk)

[0165] This simple linear relationship simplifies the calibration of the device and enables exceptionally high accuracy in determining the focal position.

[0166] Furthermore, Figure 8 It shows the relationship with Figure 1aThis is another variation of the embodiment of the beam analyzer device 10, opposite to the beam splitter device 52. An exemplary variation of the beam splitter device 52 shown here includes two plates as sub-beam deflection elements 53, 54. The plates 53, 54 are aligned in the beam direction in front of, or in this case behind, the corresponding sub-apertures 32, 33, and are tilted at an angle relative to each other, such that the two sub-beams 72, 73 are offset from each other in the second lateral direction 37. Plates are generally less expensive than wedges; furthermore, the distance w between beam points 92, 93 in the second lateral direction 37 can be adjusted by the tilt angle of the plates. All other elements shown correspond to… Figure 1a The description.

[0167] Figure 9 It shows something similar to Figure 1a The beam analysis apparatus 10 includes an imaging device 50 and a beam splitter device 52 arranged in a common configuration. For this purpose, a lens 51 included in the imaging device 50 is divided into two halves, and the two lens halves are displaced relative to each other in a direction perpendicular to a first lateral direction 31 defined by a distance k. All other elements shown correspond to... Figure 1a The description.

[0168] Figure 10 Another embodiment of the beam analysis apparatus 10 according to the present invention is shown. The beam analysis apparatus 10 is additionally equipped with a beam folding device 60, which would otherwise correspond to... Figure 1a The beam folding device 60 includes a beam splitter 61 and a reflector 64. In this embodiment, the beam folding device 60 is positioned behind the beam shaping device 12. The beam splitter 61 (which may be, for example, a beam splitter cube) deflects the radiation component of the shaped sample beam 79. The deflected beam component illuminates the reflector 64 and is reflected back into the beam splitter 61. The reflection back by the reflector 64 folds the beam, thereby forming a first folded beam path. After passing through the beam splitter 61 again, the shaped sample beam 79 illuminates the detector 40. The area surrounding the detector 40 in the figure is shown in magnified detail in the lower part of the figure, where the lower detail is represented in the xz plane, that is, it shows a plane perpendicular to the plane in the upper part of the figure.

[0169] The direction of the local optical axis 11 is changed by deflecting the shaped sample beam 79 through the beam folding device 60. Therefore, in this case, the first lateral direction 31 in the region of the detector 40 does not point to the same direction as the first lateral direction 31 defined by the distance k in the sub-beam release plane 19. The first lateral direction 31 is always understood relative to the local coordinates of the sample beams 70, 79. The local coordinates of the sample beams 70, 79 are always oriented relative to the local optical axis 11. The local optical axis 11 always forms the z-axis of the local coordinates. Therefore, the first lateral direction 31 is always oriented perpendicular to the local optical axis 11 (that is, with the local z-axis) (that is, laterally). The same applies to the second lateral direction 37; the second lateral direction 37 is also always understood in conjunction with the local coordinates of the sample beams 70, 79. Therefore, the first lateral direction 31 and the second lateral direction 37 are always perpendicular to the local optical axis, and the second lateral direction 37 is always laterally aligned with the first lateral direction 31. The local optical axis and the local z-axis can even be precisely reversed by reflection, for example at the reflecting mirror 64. Here, the first lateral direction 31 and the second lateral direction 37 are changed accordingly.

[0170] The first lateral direction 31 is defined by the imaginary connection of the center points of the sub-apertures 32 and 33 (that is, by distance k) and is generated by beam redirection corresponding to the change of the local optical axis 11.

[0171] The beam folding device 60 makes the design of the beam analysis device 10 compact and space-saving. Figure 10 All other elements shown correspond to Figure 1a The description.

[0172] Figure 11a It shows something similar to Figure 1a and Figure 10The beam analysis device 10 includes an additional beam folding device 60. Here, the beam folding device 60 includes a beam splitter 61 and two mirrors 56 and 57. In this embodiment, the beam folding device 60 is positioned behind the modulation device 20. The radiation components of the released sub-beams 72 and 73 are deflected by the beam splitter 61. Of the deflected radiation components, one of the sub-beams 72 and 73 illuminates one of the mirrors 56 and 57. The two mirrors 56 and 57 reflect the sub-beams 72 and 73 back into the beam splitter 61. The reflections by the mirrors 56 and 57 form a first folded beam path. The two mirrors 56 and 57 are tilted at a small angle to each other, and in this way simultaneously form a beam splitter device 52. For this purpose, the difference between the normal directions on the mirror surfaces of the mirrors 56 and 57 is aligned along a second lateral direction 37. The angular difference between the normal directions on the mirror surfaces of the mirrors 56 and 57 can be, for example, in the range of 0.01° to 3°. After passing through beam splitter 61 again, the two deflected sub-beams 72 and 73 are guided onto detector 40 as shaped sample beams 79. Mirrors are generally less expensive than wedges; furthermore, the distance w between beam points 92 and 93 in the second lateral direction 37 can be adjusted by the tilt angle of mirrors 56 and 57. All other components shown are as follows... Figure 1a and Figure 10 As described in [the text].

[0173] Figure 11b It shows the relationship with Figure 11a The same beam analysis device 10. Figure 11b The beam splitter 61 of the beam folding device 60 is shown by way of example; it can be designed not only as a beam splitter cube, but also as a beam splitter mirror, or a beam splitter plate. All other elements shown correspond to... Figure 1a , Figure 10 and Figure 11a The description.

[0174] Figure 12 It shows something similar to Figure 11a The beam analysis device 10. With Figure 11a In contrast to the example embodiment, the modulation device 20 is not arranged in front of the beam folding device 60, but rather within the beam folding device 60 in the beam folding path, in a plane substantially the same as that of the reflectors 56 and 57. All other elements shown correspond to Figure 1a , Figure 10 and Figure 11a The description.

[0175] Figure 13 It shows something similar to Figure 12 The beam analysis device 10. With Figure 12Compared to the previous embodiment, the modulation device 20 arranged in the folded beam path is also designed as a beam splitter device 52. Here, the modulation device 20 is composed of mirrors 56 and 57. Mirrors 56 and 57 simultaneously form the beam splitter device 52 and are also part of the beam folding device 60. Sub-apertures 32 and 33 are formed at the edges of mirrors 56 and 57. Therefore, in this variant of the embodiment, the release of sub-beams 72 and 73 occurs through the reflection of radiation within sub-apertures 32 and 33 or mirrors 56 and 57, while radiation outside sub-apertures 32 and 33 is not reflected and therefore does not contribute to the intensity distribution on detector 40. Figure 11a In a variation of the embodiment, the difference between the normal directions on the mirror surfaces of the mirrors 56 and 57 along the second lateral direction 37 is aligned to form a distance w on the second lateral direction 37 between the beam points 92 and 93 on the detector 40. All other elements shown correspond to Figure 1a , Figure 10 and Figure 11a The description.

[0176] Figure 14 It shows something similar to Figure 11aThe beam analysis apparatus 10 includes a beam folding device 60 comprising a beam splitter 61 and two mirrors 56, 57, wherein the mirrors 56, 57 also form a beam splitter device 52. In the embodiment shown here, the beam folding device 60 is also used to form a second folded beam path to the detector 40. For this purpose, the second beam components of the sub-beams 72, 73 emanating from the beam splitter 61 are reflected back by another pair of mirrors 58, 59 forming the second beam splitter device 55, and the beam components of the sub-beams 72, 73 from the two folded beam paths are superimposed again on the common propagation path to the detector 40 by the same beam splitter 61. Thus, the sub-beams 72, 73 can each form two beam points, that is, a first pair of beam points 92, 93 are formed through the first folded beam path, and a second pair of beam points 92, 93 are formed through the second folded beam path, such that a maximum of four beam points can be formed on the detector 40. The beam points 92 and 93 imaged via the first folded beam path have a spacing a1 in the first lateral direction, and the beam points 92 and 93 imaged via the second folded beam path have a spacing a2 in the first lateral direction. A beam splitter device 52 in the first folded beam path forms a distance w1 between the beam points 92 and 93 imaged via the first folded beam path in the second lateral direction 37. Correspondingly, a beam splitter device 55 in the second folded beam path forms a distance w2 between the beam points 92 and 93 imaged via the second folded beam path in the second lateral direction 37. The lengths of the two folded beam paths can be selected to be different. The selection of different beam path lengths can advantageously increase the detection range of changes in the position of the beam analysis device 10 relative to the beam focus 71, and / or enable the beam analysis device 10 to be used at different beam focus positions or at distances z from the plane 19 of the sub-beam origin. s Sample beams 70 with different beam divergences. Figure 14 All other elements shown correspond to Figure 1a , Figure 10 and Figure 11a The description.

[0177] Figure 15a It is based on Figure 14This is a schematic example illustration of the intensity distribution on detector 40 in a beam analyzer 10 with two folded beam paths. The intensity distribution on detector 40 consists of two pairs of beam points 92, 93. The first pair of beam points 92, 93 are separated by a distance A1 in the first transverse direction 31. Distance a1 is zero during the propagation of the beam points shown and changes as the axial position of the beam focus 71 changes. Due to the deflection of sub-beams 72, 73 by beam splitter device 52, the first pair of beam points 92, 93 are separated by a distance w1 in the second transverse direction 37. Distance w1 does not change when the axial position of the beam focus 71 changes. The second pair of beam points 92, 93 are separated by a distance a2 in the first transverse direction 31 and by a distance w2 in the second transverse direction 37 due to the deflection of sub-beams 72, 73 by second beam splitter device 55. Distance w2 does not change when the axial position of the beam focus 71 changes.

[0178] Figure 15b It shows the relationship with Figure 15a Same basis Figure 14 An exemplary illustration of the intensity distribution on detector 40 in a beam analysis device 10 with two folded beam paths. Figure 15b The diagram also illustrates the changes in distances a1 and a2 between beam points 92 and 93 on detector 40 when the axial position of beam focus 71 is changed for two beam point pairs. The apostrophe reference symbols in the figure indicate details of how the axial displacement of the beam focus changes. The first pair of beam points 92 and 93 are separated by a distance a1 in the first transverse direction 31. This changes to a1' when the axial position of beam focus 71 changes. In the second transverse direction 37, the first pair of beam points 92 and 93 are separated by a distance w1, which remains unchanged when the axial position of beam focus 71 changes. In the first transverse direction 31, the second pair of beam points 92 and 93 are separated by a distance a2, which changes to a2', for example, when the axial position of beam focus 71 changes. In the second transverse direction 37, the second pair of beam points 92 and 93 are separated by a distance w2, which remains unchanged when the axial position of beam focus 71 changes. Therefore, as the axial beam focal point position changes, the positions of the two pairs of beam points 92 and 93 on the detector 40 extend along four different paths. Thus, the beam point allocation is always well-defined, and the magnitude and direction of the change can be clearly determined.

[0179] Figure 16a The beam analysis device 10 is shown, which is basically in conjunction with... Figure 14 It is constructed in the same way as the beam analysis device in the middle. Figure 16aA variation of the illustrated embodiment further includes a shutter device 69. With shutter device 69, one of the two folded beam paths can optionally be optically blocked. In the embodiment shown here, a deflector 68 is arranged in the second folded beam path such that the two folded beam paths are partially parallel. The shutter device 69 can then be implemented, particularly simply, as a linearly movable shutter, or a shutter that can pivot about an axis. In this way, it is possible to control which beam path the sub-beams 72, 73 are imaged onto the detector 40. This can be advantageous for reliably identifying the corresponding beam paths 92, 93 on the detector 40. All other elements shown correspond to… Figure 1a , Figure 10 , Figure 11a and Figure 14 The description.

[0180] Figures 16b to 16d It shows Figure 16a Other variations of the embodiment of the beam analysis device 10 have different embodiment options for separating or decoupling the sample beam 70 from the energy beam 77.

[0181] Figure 16b A beam analysis apparatus 10 is shown, wherein a sample beam 70 is decoupled from an energy beam 77 by a decoupling device 14. For this purpose, the beam analysis apparatus 10 includes a decoupling device 14 having a beam decoupler 15, which in this embodiment is implemented by a beam splitter plate at the interface of the beam splitter plate, where a portion of the intensity of the energy beam 77 is reflected as the sample beam 70. To adjust the degree of reflection, the plate can be coated, for example, with a reflection reduction layer. Typically, a low residual reflectivity of the antireflective coating in the range of about 0.05% to about 1% is sufficient to provide the sample beam 70. Therefore, the decoupling device 14 also serves to attenuate the radiation intensity of the sample beam 70. The energy beam 77 has an energy beam focus 76. Since the sample beam 70 is decoupled from the energy beam 77 without changing its geometry and beam parameters, the energy beam focus 76 is simultaneously the beam focus 71 of the sample beam 70. All other elements shown correspond to… Figure 14 and Figure 16a The description.

[0182] Figure 16c The beam analysis device 10 shown is Figure 16b The illustrated device differs in that it includes an additional beam absorber device 44, which is also configured to measure beam power. For this purpose, the energy beam 77 is guided to the absorber and power measuring device 44 after passing through the decoupling device 14 with a beam decoupler 15. In the illustrated embodiment, an evaluation device 45 is connected to the absorber and power measuring device 44. The measurements generated by the absorber and power measuring device 44 can be recorded and / or processed by the evaluation device 45. All other elements shown correspond to the preceding figures, particularly... Figure 16a The description.

[0183] Figure 16d A variation of an embodiment of the beam analysis device 10 is shown, which largely corresponds to Figure 16c The embodiment shown here is in the form of a beam decoupler 14. In the embodiment shown here, the decoupling device 14 includes a beam decoupler 15 and a second beam decoupler 16, the second beam decoupler 16 being arranged downstream of the beam decoupler 15. In this way, the decoupling device 14 achieves particularly high beam attenuation of the sample beam 70. For example, as a result of the two-stage decoupling, the intensity of the sample beam 70 can be in the range of 0.002% to 0.2% of the intensity of the energy beam 77. Therefore, the focal position of the energy beam 77 with particularly high power can also be determined by the two beam decouplers 15, 16 connected in series. For example, such an energy beam can be generated by a high-power laser and has a power of several kilowatts. Additionally, the second output coupling can occur in the case of reflection in a plane rotated 90° relative to the first reflection, thereby compensating for differences in the degree of polarization-related reflection. Residual radiation through the second beam decoupler 16 can be collected by another absorber device 43. All other elements shown correspond to the preceding figures, particularly... Figure 16a The description.

[0184] Figure 17An embodiment of the beam analysis apparatus 10 includes a beam shaping device 12, a beam folding device 60, a detector 40, and an evaluation device 45. Preferably, the beam shaping device 12, the beam folding device 60, the detector 40, and the evaluation device 45 are arranged together in a housing. The beam shaping device 12 includes an imaging device 50 having at least one optical lens 51, a modulation device 20, and a beam splitter device 52 having mirrors 56 and 57. The beam folding device 60 includes a beam splitter 61, a mirror 64, and mirrors 56 and 57, the latter of which is also part of the beam splitter device 52. The beam folding device 60 is arranged behind the lens 51 of the imaging device 50 in the beam direction. The beam splitter 61 splits the sample beam 70 into two radiation components. The first of the two radiation components passes through the modulation device 20 and the beam splitter device 52, which are arranged in closely spaced planes. Through the modulation device 20, at least two sub-beams 72 and 73 are released in a sub-beam release plane 19 having two sub-apertures 32 and 33. The center points of sub-apers 32 and 33 are spaced k apart from each other in the first transverse direction 31. The two sub-beams 72 and 73 are then reflected back into the beam splitter 61 by mirrors 56 and 57 of the beam folding device 60 and beam splitter device 52, respectively, thus forming a first folded beam path. The two mirrors 56 and 57 are tilted at a small angle to each other, and in this way simultaneously form the beam splitter device 52. For this purpose, the difference between the normal directions on the mirror surfaces of mirrors 56 and 57 is aligned along a second transverse direction 37, which is perpendicularly aligned to the first transverse direction 31. The second of the two radiation components, after passing through the beam splitter 61, illuminates mirror 64 and is reflected back into the beam splitter 61, thus forming a second folded beam path. In the second folded beam path, the intensity distribution of the sample beam 70 is not modulated, thus forming an unmodulated beam 78 in the second beam path. In beam splitter 61, two radiation components from two folded beam paths are superimposed and imaged onto detector 40 along a common propagation path having a local optical axis 11. Therefore, the intensity distribution on detector 40 comprises three beam points 92, 93, and 98. Two beam points 92 and 93 are formed, as explained above, by imaging two sub-beams 72 and 73 formed in the first folded beam path by modulation device 20 and beam splitter device 52. Beam points 92 and 93 are spaced apart by a distance a in the first transverse direction 31 on detector 40. Distance a changes with the axial position of beam focus 71. Based on distance a or the change in distance a, evaluation device 45 determines the axial focal position or the change in axial focal position of beam focus 71. By deflecting sub-beams 72 and 73 through beam splitter device 52, beam points 92 and 93 are spaced apart by a distance w in the second transverse direction 37. Distance w does not change with the axial position of beam focus 71.A third beam spot 98 is formed on the detector 40 by imaging the unmodulated beam 78 propagating along the second folded beam path. Therefore, the beam spot 98 of the unmodulated beam represents the original intensity distribution of the sample beam 70 or the energy beam 77 from which the sample beam 70 can be decoupled. In particular, the beam spot 98 can also be an image of the beam focus 71. Based on the image scale imaged by the imaging device 50, the intensity distribution and / or diameter of the beam focus 71 can therefore also be determined by the evaluation device 45.

[0185] Figure 18 A variation of an embodiment of the beam analysis device 10 is shown, which largely corresponds to Figure 17 The embodiment shown here is in the form of an example. In the embodiment shown here, the unmodulated beam 78 forming beam point 98 on detector 40 is imaged onto detector 40 in a magnified manner. For this purpose, another imaging device 63 having at least one optical lens is arranged in a second folded beam path between beam splitter 61 and mirror 64. In particular, imaging device 63 may include a concave lens. To compensate for changes in image position caused by imaging device 63, the second folded beam path may have a different beam path length than the first folded beam path. As a result of the magnified image of the unmodulated beam 78, the intensity distribution and / or beam diameter can be determined from beam point 98 with higher resolution and accuracy. All other elements shown correspond to the description in the foregoing figures, in particular Figure 17 The description.

[0186] Figure 19a The variations of the embodiments shown also substantially correspond to Figure 17 The form of the embodiment. In this regard, reference is also made to... Figure 17The description is as follows. In a variation of the embodiment shown herein, the beam path length in the second folded beam path is variablely adjustable. For this purpose, the reflector 64 is arranged such that it can be moved axially, for example by a linear guide, and coupled to the positioning device 66. The positioning device 66 allows the reflector 64 to be moved to different axial positions (64, 64'). The positioning device 66 may include, for example, a plunger coil driver, thereby enabling very rapid adjustment, for example, within milliseconds. An evaluation device 45 may be configured to control the positioning device 66. The evaluation device 45 may also be configured to exchange data with the positioning device 66, for example, exchanging information about changes in the reflector position or adjustment path. In this way, multiple (preferably at least 3, particularly preferably at least 10) reflector positions can be set continuously, and the respective intensity distributions of the beam points 98 on the detector 40 can be recorded. Based on these data, various beam parameters of the sample beam 70, such as focal diameter, beam divergence, and / or beam parameter products, can be determined. Therefore, the beam analysis apparatus 10 shown here can determine the axial beam focal point position in near real-time, and measure the beam caustics (beam envelope) of the sample beam 70 or energy beam 77 in almost real-time, at least for a very short time. This also makes it possible to measure the beam according to the ISO 11146 standard in a very short time, for example, less than 1 second.

[0187] Figure 19b and 19c It shows Figure 19a Other variations of the embodiment of the beam analysis device 10 have various embodiment possibilities for separating or decoupling the sample beam 70 from the energy beam 77.

[0188] therefore, Figure 19b A beam analysis apparatus 10 is shown, wherein the sample beam 70 is decoupled from the energy beam 77 by a decoupling device 14. The beam analysis apparatus 10 corresponds to... Figure 19a The apparatus shown further includes a decoupling device 14 having a beam splitter plate as a beam decoupler 15. A portion of the intensity of the energy beam 77 is reflected at the boundary surface of the beam decoupler 15 as a sample beam 70. Therefore, the decoupling device 14 also serves to attenuate the radiation intensity of the sample beam 70. The energy beam 77 has an energy beam focus 76. Since the sample beam 70 is decoupled from the energy beam 77 without changing its geometric properties and beam parameters, the energy beam focus 76 is simultaneously the beam focus 71 of the sample beam 70. All other elements shown correspond to... Figure 17 and 19a The description.

[0189] Figure 19c The beam analysis device 10 shown is Figure 19bThe device shown differs in that it has an additional beam absorber device 44, which is also configured to measure beam power. For this purpose, after the energy beam 77 passes through the decoupling device 14 with the beam decoupler 15, the energy beam 77 is guided to the absorber and power measuring device 44. The measurements generated by the absorber and power measuring device 44 can be recorded and / or processed by the evaluation device 45. All other elements shown correspond to the description in the foregoing figures.

[0190] Figures 19d to 19f It shows the relationship with Figure 19a The same beam analysis device 10. The attached figure shows... Figure 19a The beam analysis device 10 is used in the laser processing optics 100. Figures 19d to 19f The diagram illustrates various possibilities for decoupling the sample beam 70 from the laser beam 77 guided in the laser processing optics 100.

[0191] For example, Figure 19d A portion of the laser beam 77 is shown extracted via a beam decoupler 15 integrated into a decoupling device 14 within a laser processing optics 100. The laser processing optics 100 typically also includes a collimator 113, a focusing device 116, and a protective glass 120. The beam decoupler 15 can, for example, be a tilted plate coated with a dielectric AR (anti-reflective) layer, utilizing the residual reflection of the AR layer. Typically, the dielectric anti-reflective layer reflects a portion of the radiation intensity, which can range from about 0.05% to 1%. Figure 19d In the example, a portion of the laser beam 77 collimated in front of collimator 113 is thus decoupled. The source point of the decoupled sample beam 70 forming the beam focus 71 is, for example, the end 110 of the optical fiber. For example, this arrangement is suitable for determining, by the beam analysis device 10, the actual position or a change in the actual or virtual position of the beam exit point (e.g., the end 110 of the optical fiber) in the case of an adjustable collimator 113. This position can then be used to calculate the position of the energy beam focus 76, onto which the laser processing optics 100 focuses the energy beam or laser beam 77. In the case of thermal lensing in collimator 113, for example due to contamination of collimator 113, the change in the focus position can also be determined online in this way, that is, preferably in real time during laser processing. All other elements shown correspond to Figure 19a The description.

[0192] exist Figure 19eIn the example, beam decoupler 15 is arranged to decouple a portion of the beam component reflected from the protective glass 120 of the laser processing optics 100. The beam focus 71 in the reflected component of the radiation is a mirror image of the laser beam focus 76, therefore any change in the position of the laser beam focus 76 will also affect the position of the beam focus 71 determined by the beam analysis device 10. To distinguish reflections from the two boundary surfaces (front and back) of the protective glass 120, the protective glass 120 can be arranged, for example, at a small angle. Alternatively, a wedge-shaped plate can be used as the protective glass 120 to achieve this purpose. All other elements shown correspond to… Figure 19a and 19d The description in the text.

[0193] Figure 19f It also shows with Figure 19a The same beam analysis device 10 as in the middle. Here, the beam analysis device 10 is similar to... Figure 19e The beam decoupler 15 of the decoupling device 14 is coupled to the laser processing optics 100 and receives a sample beam 70 coupled from the decoupling device 14, which is reflected back at the protective glass 120 as part of the intensity of the laser beam 77. In this embodiment, the beam decoupler 15 of the decoupling device 14 integrated in the laser processing optics 100 is a high-reflectivity mirror, such as a plate with a high-reflectivity dielectric coating, which is actually primarily configured to deflect the laser beam 77 in the laser processing optics 77. This takes advantage of the fact that a high-reflectivity (HR) coated mirror has a residual transmittance in the range of 0.05% to 1%. This transmitted radiation component forms the decoupled sample beam 70. All other elements shown correspond to Figure 19a and 19d The description in the text.

[0194] Figure 20 It shows the basis Figure 14This is a variation of the embodiment of the beam analysis apparatus 10. The beam analysis apparatus 10 includes a beam folding device 60 for forming two folded beam paths and a modulation device 20 disposed in front of the beam folding device 60. Furthermore, the beam analysis apparatus 10 includes a second beam splitter 62, another imaging device 63, and a second detector 42. The second beam splitter is disposed between the lens 51 of the imaging device 50 and the modulation device 20. Through the second beam splitter 62, the radiation component is decoupled from the sample beam 70 to form an unmodulated beam 78, which is guided and imaged onto the second detector 42. The other imaging device 63 is arranged in front of the second detector 42 in the beam direction and, in conjunction with the imaging device 50, is used to magnify and image the unmodulated beam 78 onto the second detector 42. Therefore, the beam point 98 formed by imaging the unmodulated beam 78 onto the second detector 42 can be a magnified image of the beam focus 71, or a magnified beam cross-sectional plane of the sample beam 70 from the beam caustic region near the beam focus 71. The intensity distribution recorded by the second detector 42 can be evaluated by the evaluation device 45. In this way, the signal from detector 40 is used to determine the focal position, and the signal from the second detector 42 is used to determine the intensity distribution, beam profile, and / or beam diameter of the cross-section from or near the beam focal point 71. Figure 17 or Figure 18 Compared to the variant of the embodiment, the advantage of this variant is that the entire sensor surface of the detector 42 can be used for the intensity distribution of the unmodulated beam 78, while Figure 17 or Figure 18 In one embodiment, beam points 92 and 93 require a portion of the sensor surface.

[0195] Figure 21 It shows the basis Figure 14This is another variation of the embodiment of the beam analysis apparatus 10. The beam analysis apparatus 10 includes a beam folding device 60 for forming two folded beam paths and a modulation device 20 disposed in front of the beam folding device 60. Furthermore, the beam analysis apparatus 10 here includes a second beam splitter 62, a mirror 64, a positioning device 66, and a second detector 42. The second beam splitter is disposed between the lens 51 of the imaging device 50 and the modulation device 20. Through the second beam splitter 62, the radiation component is decoupled from the sample beam 70 to form an unmodulated beam 78. The radiation component decoupled by the second beam splitter 62, that is, the unmodulated beam 78, is guided onto the mirror 64, reflected back by the mirror 64, and subsequently guided onto the second detector 42 and imaged to form a beam point 98 on the second detector 42. The length of the propagation path of the unmodulated beam 78 is variably adjustable. For this purpose, the mirror 64 is arranged such that it can be axially moved, for example, by a linear guide, and is coupled to the positioning device 66. The reflector 64 can be moved to different axial positions (64, 64') via the positioning device 66. The positioning device 66 may include, for example, a plunger coil driver, thereby enabling very rapid adjustment, e.g., within milliseconds. Furthermore, an evaluation device 45 can be configured to control the positioning device 66. The evaluation device 45 can also be configured to exchange data with the positioning device 66, e.g., exchange information about changes in the reflector position or adjustment path. In this way, multiple (preferably at least 3, particularly preferably at least 10) different reflector positions can be continuously set, and the respective intensity distributions of the beam points 98 can be recorded on the second detector 42. Based on these data, various beam parameters of the sample beam 70, such as focal diameter, beam divergence, and / or beam parameter products, can be determined. Therefore, the beam analysis device 10 shown here is capable, on the one hand, of determining the axial beam focal position in near real-time, and on the other hand, of measuring the beam caustics of the sample beam 70 or energy beam 77 in almost real-time, at least within a very short time. Thus, beam measurements conforming to ISO 11146 can also be performed within a very short time, e.g., less than 1 second. Figure 19a Compared to the illustrated device, the variation of this embodiment has the advantage that the entire sensor surface of the second detector 42 can be used for the intensity distribution of the unmodulated beam 78, while... Figure 19a In one embodiment, beam points 92 and 93 require a portion of the sensor surface.

[0196] Figures 22 to 24An embodiment of a beam analysis device 10 is shown, which further includes a far-field analysis device. This far-field analysis device can be combined with any of the aforementioned beam analysis devices 10. The far-field analysis device includes a second beam splitter 62, another imaging device 67, and a second detector 42. The second beam splitter 62 is arranged in the beam direction behind at least one lens 51 of the imaging device 50 and in front of the modulation device 20. Through the second beam splitter 62, radiation components are decoupled from the sample beam 70 to form an unmodulated beam 78, which is guided onto the second detector 42 to form a beam intensity distribution 99 on the second detector 42. Between the second beam splitter 62 and the second detector 42, another imaging device 67 is arranged, which includes at least one optical lens, or may be a multi-lens objective. The other imaging device 67, together with the imaging device 50 and the lens 51 contained therein, forms a combined lens system. This combined lens system has a combined focal length and an image-side focal plane of the combined lens system. The second detector 42 is precisely arranged in the image-side focal plane of the combined lens system. Therefore, the combined lens system forms a so-called Fourier objective for the second detector 42, because the intensity distribution 99 of the unmodulated beam 78 formed on the second detector 42 represents the Fourier transform of the intensity distribution of the sample beam 70. Thus, the intensity distribution 99 on the second detector 42 is a so-called far-field intensity distribution, and it is independent of the axial position of the beam focus 71. Therefore, in particular, the divergence angle of the sample beam 70 can be determined from this intensity distribution 99.

[0197] Figure 22 This represents one embodiment of a beam analyzer 10, wherein the far-field analyzer just described is integrated into the beam analyzer 10, which in other respects corresponds to Figure 14 The apparatus shown. To explain... Figure 22 Other components, therefore refer to Figure 14 The description.

[0198] Figure 23 This illustrates an embodiment of the beam analysis device 10, wherein the far-field analyzer just described is integrated into the beam analysis device 10, which in other respects corresponds to... Figure 17 The apparatus shown. To explain... Figure 23 Other components, therefore refer to Figure 17 The description. Figure 23 Variations of the embodiment make it possible to determine a great deal of information about the sample beam 70 or about the energy beam 77: the axial focal position and the intensity distribution in or near the beam focal point can be determined based on the signal from the detector 40, and far-field characteristics can be determined together with the signal from the second detector 42. This provides extensive geometric beam information that can be determined virtually in real time and can be used, for example, to control laser processing operations.

[0199] Figure 24 An embodiment of the beam analysis device 10 is shown, wherein the far-field analyzer just described is integrated into the beam analysis device 10, which in other respects corresponds to Figure 19a The apparatus shown is for explanation. Figure 24 Other components, therefore refer to Figure 19a The description. Figure 24 Variations of the embodiments enable the determination of the axial focal position, near-field intensity distribution, and far-field intensity distribution in a very short time, almost in real time, as well as complete beam measurements that also conform to ISO 11146.

[0200] Figure 25 The embodiment of the beam analysis device 10 includes a beam shaping device 12 for releasing a total of four sub-beams 72, 73, 74, and 75. For this purpose, the modulation device 20 has four mutually spaced transmission zones 21, 22, 23, and 24, which define four sub-apertures 32, 33, 34, and 35. In this embodiment, the sub-apertures 32, 33, 34, and 35 are arranged along a transverse axis. Here, a first transverse direction 31 is defined by a line connecting the center points of two sub-apertures (e.g., sub-apertures 32 and 33), wherein the distance k between the center points of the sub-apertures is... 12 According to the invention, by means of a beam splitter device 52, at least one of the sub-beams 72, 73 released by sub-apertures 32, 33 is deflected or deflected in the second lateral direction 37. In this embodiment, the two sub-beams 72, 73 are deflected in opposite directions in the second lateral direction 37. For this purpose, each sub-aperture 32, 33 is assigned a corresponding sub-beam deflection element 53, 54. Other sub-apertures 34, 35 defined by transmission regions 23 and 24 are also arranged in this example of the embodiment at a distance k apart from each other along the first lateral direction 31. 34 Here, transmission regions 23 and 24 are arranged further outward than transmission regions 21 and 22, so that when sub-beams 74 and 75 are released through sub-apertures 34 and 35, and the beam focal position 71 changes, a larger angular change occurs compared to the case of sub-beams 72 and 73 from sub-apertures 32 and 33, which are closer to the optical axis 11. As a result, the positional change of beam points 94 and 95 generated by sub-beams 74 and 75 on detector 40 is greater than the positional change of beam points 92 and 93 of sub-beams 72 and 73. Using different distances k... 12 k 34The advantage of the two pairs of apertures is that, on the one hand, higher sensitivity and accuracy are achieved in determining the axial position of the beam focus 71 by using the pair of apertures located further away; on the other hand, even in the case of a sample beam 70 or energy beam 77 with a smaller beam aperture, the more outwardly positioned transmission regions 23, 24 will not be illuminated or will not be fully illuminated, while the more inwardly positioned transmission region pair 21... ； 22 is still illuminated by the sample beam, enabling reliable measurement. This means that when using a modulation device 20 with two or more sub-apertures at different distances from each other, the available aperture range of the energy beam 77 and the accuracy of the measurement are both increased. In the example of the embodiment shown here, the sub-beams 74, 75 emitted from the additional sub-apertures 34, 35 are also deflected in opposite directions in the second transverse direction 37. For this purpose, a sub-beam deflection element 54b is assigned to sub-aperture 34, and a sub-beam deflection element 54c is assigned to sub-aperture 35. On the detector 40, the beam points 92, 93 generated by the sub-beams 72, 73 are spaced apart by a distance a in the first transverse direction 31. 12 The distance a 12 It depends on the axial position of the beam focus 71, and can also be zero, for example, as Figure 25 As shown. The beam points 94 and 95 generated by sub-beams 74 and 75 are spaced apart by a distance α in the first lateral direction 31 on the detector 40. 34 Distance a 34 It also depends on the axial position of the beam focus 71, and can, for example, be zero. Figure 25 The lower part shows the projection of the device in the second lateral direction 37, which is laterally aligned with the first lateral direction 31 and, for example, the x-axis, showing the operating mode of the beam splitter device 52. Through the sub-beam deflecting elements 53, 54, 54b, and 54c, in each case, the sub-beams 72, 73, 74, and 75 are deflected by different amounts in the direction of the second lateral direction 37. Therefore, the beam points 92, 93, 94, and 95 are spatially separated from each other on the detector 40, thus allowing their positions on the detector 40 to be clearly determined. The beam points 92 and 93 generated by the sub-apertures 32 and 33 are spaced apart from each other on the detector 40 along the second lateral direction 37 by a distance w. 12 Furthermore, the beam points 94 and 95 generated by the sub-apertures 34 and 35 are spaced apart from each other along the second transverse direction 37 on the detector 40 by a distance w. 34 The distance in the second lateral direction depends on the individual deflections of the sub-beam deflection elements 53, 54, 54b, and 54c, and on the axial position of the detector 40, such as the distance s between the modulation device 20 and the detector 40. This means that the distance w 12 and w 34Essentially independent of the axial position of the beam focus 71, the beam points 92, 93, 94, and 95 on the detector 40 always remain separate regardless of the axial position of the beam focus 71. However, the distance α between beam points 92, 93 and 94, 95 in the first lateral direction 31 remains constant. 12 and a 34 It is a function of the axial position of the beam focus 71, thus it can be seen from a 12 and a 34 Two distances determine the axial position of the beam focal point 71. According to the invention, there are two sub-beams, namely first and second sub-beams, at least one of which is offset in the second lateral direction 37. Figure 25 In the example of the embodiment, sub-beams 72 and 73 form the first and second sub-beams. However, sub-beams 74 and 75 can also be regarded as the first and second sub-beams according to the invention, because in the example of this embodiment, at least one of the sub-beams 74 and 75 is also offset in the second lateral direction 37. Figure 25 The other components of the beam analysis device 10 shown correspond to Figure 1a The form of the illustrated embodiment. For explanation Figure 25 Other components, therefore refer to Figure 1a The description.

[0201] Figure 26a The views along the transverse axes 31 and 37 show the methods for releasing, such as Figure 25 The modulation device 20 of the four sub-beams 72, 73, 74, and 75 of the beam analysis device 10 shown is illustrated. The transverse axes 31 and 37 can be, for example, local x-axis and y-axis. To clarify the operating mode, a beam splitter device 52 with sub-beam deflection elements 53, 54, 54b, and 54c is also shown in the figure, by which the deflection of sub-beams 72, 73, 74, and 75 is achieved, superimposed on the modulation device 20. In this example, the modulation device 20 has four sub-apertures 32, 33, 34, and 35, defined by four mutually separated transmission zones 21, 22, 23, and 24, and arranged along the first transverse axis 31. The center points of the inner sub-apertures 32 and 33 are spaced k apart from each other. 12 Furthermore, the center points of the external sub-holes 34 and 35 are spaced k apart from each other. 34Transmission zones 21, 22, 23, 24 and therefore sub-apertures 32, 33, 34, 35 have defined dimensions b1, b2, b3, b4, whereby the dimensions are widths, or, in the case of circular transmission zones, the diameters of the respective transmission zones. The dimensions b1, b2, b3, b4 of the transmission zones can be the same or different. Since the intensity in the beam distribution of the laser beam typically decreases radially outward, it is advantageous to choose that the dimensions of the outer transmission zones (here, 23 and 24) are larger than the dimensions of the inner transmission zones (here, 21 and 22). It is advantageous to choose transmission zones with the same radial distance from the optical axis in pairs with identical dimensions.

[0202] Figure 26b It schematically shows the following based on Figure 25 The intensity distribution of beam points 92, 93, 94, and 95 on the detector 40 of the beam analysis device 10, which is equipped with a modulation device 20, such as... Figure 26a As shown in the figure. The figure also shows the distance 'a' between beam points 92 and 93 when the axial position of beam focus 71 changes. 12 The change and the distance a between beam points 94 and 95 34 The change is indicated by the apostrophe reference symbol in the figure, which shows the details altered by the axial shift of the beam focus. The distance 'a' between beam points 92 and 93 in the first lateral direction 31 is... 12 For example, when the axial position of the beam focus 71 changes, the distance a 12 Change to distance a 12 In the second transverse direction 37, due to the deflection of sub-beams 72 and 73 by the beam splitter device 52, beam points 92 and 93 are separated by a distance w. 12 When the axial position of the beam focus 71 changes, this distance remains unchanged. Correspondingly, the beam points 94 and 95 have a distance a between them in the first transverse direction 31. 34 When the axial position of the beam focus 71 changes, the distance a 34 Change to distance a 34 In the second transverse direction 37, due to the deflection of sub-beams 74 and 75 by the beam splitter device 52, beam points 94 and 95 are separated by a distance w. 34 When the axial position of the beam focus 71 changes, this distance does not change. Therefore, the distance w 12 and w 34 This is independent of the axial position of the beam focus 71. When the axial beam focus position changes, the positions of beam points 92, 93, 94, and 95 on detector 40 extend along four independent paths. Therefore, the allocation of beam points is always well-defined, and the magnitude and direction of the change can be clearly determined.

[0203] Figures 27a to 30a Other examples of embodiments of the modulation device 20 and beam splitter device 52 for the beam analysis apparatus 10 according to the present invention are illustrated schematically. Figures 27b to 30b The intensity distribution of the combination of the modulation device 20 and the beam splitter device 52 shown in the foregoing figures on the detector 40 is illustrated. A common feature of all embodiments is that two sub-beams, namely a first sub-beam 72 and a second sub-beam 73, are released through two transmission zones 21, 22, and at least one of these sub-beams 72, 73 is deflected in a second lateral direction 37 transverse to a first lateral direction 31, wherein the first lateral direction 31 is defined by a connecting line, that is, by the distance k between the center points of the two sub-apertures 32, 33. 12 Limited. Here, sub-apertures 32 and 33 are formed by transmission regions 21 and 22. Unaffected by this, the modulation device 20 can have additional transmission regions 23 and 24, thereby releasing additional sub-beams 74 and 75. The additional sub-apertures 34 and 35 formed by the additional transmission regions 23 and 24 can be arranged in the same direction as the sub-apertures 32 and 33 for the two sub-beams 72 and 73, that is, in the first transverse direction 31. However, the additional sub-apertures 34 and 35 can also be arranged in different directions. All sub-beams 72, 73, 74, and 75 can be separated from each other by the beam splitter device 52. Alternatively, only the first sub-beam 72 and the second sub-beam 73 can be separated from each other.

[0204] For example, Figure 27a It shows the relationship with Figure 26a The same modulation device 20, but Figure 27a The beam splitter device 52 in the middle only deflects the first sub-beam 72 emitted by sub-aperture 32 and the second sub-beam 73 emitted by sub-aperture 33 in the second transverse direction 37, while the other sub-beams 74 and 75 emitted by other sub-apertures 34 and 35 are not deflected. Its advantage is that the beam splitter device 52 has a simpler structure.

[0205] Figure 27b The intensity distribution of beam spots 92, 93, 94, and 95 on the detector 40 of the beam analysis device 10 is shown. The beam analysis device 10 is equipped with, as shown in the diagram. Figure 27a The beam splitter device 52 in the middle. The beam points 92 and 93 of the first and second sub-beams 72 and 73 are separated by a distance w in the second transverse direction 37. 12 And therefore, when the axial focal position of the beam focal point 71 changes, at a distance w between them 12 The other beam points 94, 95 in the other sub-beams 74, 75 are not separated from each other in the second transverse direction 37, and therefore extend on the same path when the axial focal position of the beam focus 71 changes.

[0206] Figure 28a The modulation device 20 shown is similar to Figure 27a The modulation device, but here the additional sub-apertures 34, 35 formed by the other transmission regions 23, 24 are arranged in a transverse direction different from the first transverse direction 31 defined by the sub-apertures 32, 33. Therefore, as Figure 28b As shown, the paths or tracks that beam points 94 and 95 travel on detector 40 are also oriented in a different direction than the paths of beam points 92 and 93.

[0207] Figure 29a and 29b A possible example of a modulation device 20 for releasing three sub-beams through three sub-apers 32, 33, and 34 is shown, each sub-aperture having a different distance from each other. Figure 25 This description is similar to that used in other contexts, which also improves the accuracy of determining the beam focus position and expands the functional range of beams with different beam divergences.

[0208] at last, Figure 30a and 30b A modulation device 20 for releasing four sub-beams through four sub-apertures 32, 33, 34, and 35 is shown, which is similar to Figure 28a The modulation device shown. (And) Figure 28a compared to, Figure 30a The beam splitter device 52 is configured to deflect all four sub-beams, with two sub-beam pairs deflected by sub-apertures 32 and 33 on one side and by sub-apertures 34 and 35 on the other, each deflected in a different lateral direction. Thus, two beam point pairs 92, 93 and 94, 95 travel on separate paths on detector 40, but another beam point pair 94, 95 travels in a different lateral direction than the beam point pair 92, 93 from the first and second sub-beams 72, 73. This is shown in... Figure 30b middle.

[0209] The modulation device 20 and beam splitter device 52 shown should be understood as merely examples. The beam analysis device 10 according to the invention is not limited to the form of the illustrated embodiment, nor is it limited to the illustrated modulation device and beam splitter device.

[0210] Detailed description of the invention

[0211] The present invention envisions a beam analysis apparatus 10 for determining the axial position of a beam focal point 71. Here, the beam focal point 71 is either the focal point 76 of an energy beam 77 of electromagnetic radiation, or the focal point of a sample beam 70 decoupled from the energy beam 77. The beam analysis apparatus 10 includes a beam shaping device 12, a detector 40, and an evaluation device 45.

[0212] The beam shaping device 12 is configured to release at least two sub-beams 72, 73 from the energy beam 77, or from a sample beam 70 decoupled from the energy beam 77, in the sub-beam release plane 19. Here, the cross-section of each sub-beam 72, 73 within the sub-beam extraction plane 19 is defined by a corresponding sub-aperture 32, 33. In other words, the beam shaping device 12 is configured to form at least two sub-apertures 32, 33 in the sub-beam release plane 19 for releasing the corresponding sub-beams 72, 73. The sub-apertures 32, 33 are spaced apart from each other, that is, the edges of the sub-apertures 72, 73 do not contact each other. The lateral position of the sub-apertures 32, 33 is defined by their respective center points, where the term "lateral" refers to a direction in a plane perpendicular to the corresponding local optical axis (11). The center points of the sub-apertures 32, 33 have a distance k between them. Furthermore, a first lateral direction 31 is defined by the distance k between the sub-apertures 32, 33. In other words, the imaginary connecting line between the center points of the two sub-apers 32 and 33 defines the first lateral direction 31. The first lateral direction 31 lies in a plane perpendicular to the local optical axis 11. Since the local optical axis 11 in the beam path is always identified by the z-axis of the local coordinate system, the first lateral direction 31 lies in the xy plane.

[0213] The sub-beam release of the beam shaping device is implemented, for example, as a modulation device 20, which is configured to form at least two transmission regions 21, 22 and at least one blocking region 25. Here, one of the transmission regions 21, 22 forms one of two sub-apertures 32, 33. The transmission regions 21, 22 are characterized in that the radiation transmission within the transmission regions 21, 22 is significantly higher than that within the blocking region 25. The term "transmission" should be understood with respect to the intended propagation direction of the thus released sub-beams 72, 73. In particular, the radiation transmittance (or reflectance) in the transmission regions 21, 22 is at least twice that in the blocking region 25. The radiation transmittance (or reflectance) in the blocking region is preferably at least 10 times smaller than that in the transmission regions 21, 22. Particularly preferably, the radiation transmittance (or reflectance) in the blocking region is at least 100 times smaller than that in the transmission regions 21, 22.

[0214] Sub-apertures 32 and 33 have a width b along a first lateral direction 31 within the sub-beam release plane 19. The width b of sub-apertures 32 and 33 is at most equal to half the distance k between the center points of sub-apertures 32 and 33. Therefore, there exists a region (e.g., blocking region 25) between sub-apertures 32 and 33 that is at least as wide as the width b of sub-apertures 32 and 33. In other words, the distance k between the center points of sub-apertures 32 and 33 is at least twice the width b of sub-apertures 32 and 33.

[0215] The beam forming apparatus 12 is further configured to form an intensity distribution 83 having at least two beam points 92, 93 on the detector 40, and to form at least one beam point 92, 93 from each of the two sub-beams 72, 73, image the at least two sub-beams 72, 73 onto the detector 40, and deflect and / or shift at least one of the at least two sub-beams 72, 73 in a second lateral direction 37. Each of the two sub-beams 72, 73 forms at least one associated beam point 92, 93 on the detector 40. By deflecting and / or shifting at least one of the sub-beams 72, 73 in the second lateral direction 37, a distance w is formed between the positions of the two beam points 92, 93 on the detector 40 along the second lateral direction 37. The positions of the two beam points 92, 93 are preferably defined by the center point and / or centroid of the intensity distribution of the beam points 92, 93 on the detector 40. Here, the second lateral direction 37 is oriented laterally to the first lateral direction 31. The second lateral direction 37 lies in a plane perpendicular to the local optical axis 11. Therefore, like the first lateral direction 31, the second lateral direction 37 lies in a plane perpendicular to the local optical axis 11, that is, in the xy plane. The second lateral direction 37 is oriented relative to the first lateral direction 31 at an angle ranging from 30° to 150°. In particular, the second lateral direction may be oriented (at least substantially) perpendicular to the first lateral direction.

[0216] The beam shaping device 12 deflects and / or shifts the first of at least two sub-beams 72, 73 in the second transverse direction 37 and / or deflects and / or shifts the two sub-beams 72, 73 in different directions having a directional difference in alignment along the second transverse direction 37. The beam point 92 of the first sub-beam and the beam point 93 of the second sub-beam (at the detector 40 and therefore) are offset from each other by a distance w in the intensity distribution along the second transverse direction 37, which is transverse to the distance a between these beam points 92, 93 (at the detector 40 and therefore) in the intensity distribution along the first transverse direction 31, and wherein the distance a is caused only by the distance k in the first transverse direction 31.

[0217] In other words, the beam point 92 caused by the first of at least two sub-beams at the detector 40 and in the intensity distribution, and the beam point 93 caused by the second of at least two sub-beams at the detector and in the intensity distribution, are offset by a displacement w in the intensity distribution along the second lateral direction 37, in addition to being offset by a distance a along the first lateral direction 31.

[0218] Detector 40 includes a light-radiation-sensitive, two-dimensionally resolved sensor configured to convert the intensity distribution 83 illuminating the detector 40 into an electrical signal. Detector 40 can be a CCD camera, a CMOS camera, or a comparable device. The light-radiation-sensitive, two-dimensionally resolved sensor is typically a pixel-based semiconductor sensor. Detector 40 is positioned at a distance s behind the sub-beam release plane 19 along the propagation paths of sub-beams 72, 73.

[0219] The evaluation device 45 is configured to process the electrical signal of the detector 40, which represents the intensity distribution 83 on the detector 40. The evaluation device 45 is configured to determine a distance 'a' between the positions of two beam points 92, 93 on the detector 40 along a first lateral direction 31, more precisely determining the positional difference between the two beam points 92, 93 in the first lateral direction 31, wherein the positional difference between the two beam points 92, 93 in the first lateral direction 31 is the distance 'a'. The positions of the corresponding beam points 92, 93 are preferably defined by the center point and / or centroid of the intensity distribution of the corresponding beam points 92, 93 on the detector 40.

[0220] The evaluation device 45 is further configured to determine the axial position of the beam focus 71 based on distance a, and / or to determine the change in the axial position of the beam focus 71 based on the change in distance a.

[0221] The evaluation device 45 can be implemented, for example, in the form of a software program running on a computer.

[0222] To achieve the highest possible accuracy in determining the positions of beam points 92 and 93 on detector 40, it is advantageous that the widths b of sub-apertures 32 and 33 are small compared to their spacing k. Then, the beam points 92 and 93 on detector 40 are relatively small over a wide range of axial positions of the beam focus 71, and the intensity distribution within beam points 92 and 93 has little or negligible influence on determining their positions. On the other hand, the sub-apertures should not be too small, otherwise beam points 92 and 93 could be broadened by diffraction, and diffraction structures could appear outside of beam points 92 and 93. Therefore, the distance k is preferably at least 2.5 times and at most 25 times the widths b of the sub-apertures 32 and 33. Particularly preferably, the distance k is at least 3 times and at most 12 times the widths b of the sub-apertures 32 and 33. Extremely preferably, the distance k is at least 4 times and at most 7 times the widths b of the sub-apertures 32 and 33. The sub-holes 32 and 33 preferably have simple geometric shapes, such as circular or elliptical. However, the sub-holes 32 and 33 may also have square, rectangular, rhomboid, hexagonal, octagonal, trapezoidal, or similar shapes. In the case of circular sub-holes 32 and 33, the width b corresponds to the diameter of the sub-hole 32 or 33.

[0223] In another improvement of the invention, the beam shaping device 12 may also be configured to release two or more sub-beams. For this purpose, two or more (e.g., three or four) mutually spaced sub-apertures may be arranged in the sub-beam release plane 19. The multiple sub-apertures may be distributed along the first transverse direction 31. Alternatively, sub-apertures other than the two sub-apertures 32 and 33 may be arranged in a different transverse direction in the sub-beam release plane 19 than the two sub-apertures 32 and 33.

[0224] The beam shaping device 12 preferably includes a beam splitter device 52 for deflecting and / or shifting the first of at least two sub-beams 72, 73 in the second lateral direction 37.

[0225] In another improvement, the beam splitter device 52 is also configured to deflect and / or offset the two sub-beams 72, 73 in different directions, wherein the difference between the deflection directions is aligned along the second lateral direction 37.

[0226] The beam shaping device 12 of the beam analysis apparatus 10 includes a modulation device 20, an imaging device 50 having at least one optical lens 51, and a beam splitter device 52. These three devices 20, 50, and 52 can be implemented as separate devices. However, two or all three devices 20, 50, and 52 can also be implemented as a single device. For example, the modulation device 20 can be designed as a dual-aperture screen. For example, the imaging device 50 can be designed as a single converging lens 51. However, it is also possible, for example, that the modulation device 20 is provided as a mask device, for example, by directly blackening the optical lens 51 or partially blackening it within the optical lens 51. In the latter example, the modulation device 20 and the imaging device 50 are implemented as a single device. Continuing this example, the optical lens 51 can also be implemented as an aspherical freeform lens, wherein the lens surface within the sub-apertures 32, 33 has an additional tilt for deflecting the sub-beams 72, 73 in the second lateral direction 37. In this example of the embodiment used for the beam shaping device 12, all devices 20, 50, 52 are then implemented as a single device.

[0227] When the axial position of the beam focus 71 changes, the distance 'a' between the beam points 92 and 93 on the detector 40 changes in the first lateral direction 31. That is, the distance 'a' has a functional relationship with the z-position of the beam focus 71. This functional relationship is influenced by and / or defined by the following geometric quantities:

[0228] a is the distance between beam points 92 and 93 on detector 40 along the first lateral direction 31;

[0229] a' is the distance along the first lateral direction between beam points 92' and 93' on detector 40 when the beam focal position changes;

[0230] Δa is the change in the position difference between beam points 32 and 33 in the first transverse direction 31, Δa = a' - a;

[0231] k is the distance between the center points of sub-apertures 32 and 33 within the sub-beam release plane 19, wherein an imaginary connecting line between the center points of sub-apertures 32 and 33 defines the first lateral direction 31.

[0232] z s It is the distance between the axial position of the beam focus 71 and the sub-beam release plane 19;

[0233] z s The distance between the axial position of the shifted beam focus 71 and the sub-beam release plane 19;

[0234] s is the distance between the sub-beam release plane 19 and the sensor plane 39 of the detector 40;

[0235] Δz represents the change in the position of the axial beam focal point, Δz = z s -z s ';

[0236] e is the distance from the sub-beam release plane 19 to the imaging device 50 when the modulation device 20 is positioned in front of the sub-beam release plane 19 in front of the imaging device 50, or more precisely, the distance to the main plane of the imaging device 50.

[0237] d is the distance from the position of the imaging device 50, or more precisely, from the main plane of the imaging device 50 to the sub-beam release plane 19, when the modulation device 20 is positioned behind the sub-beam release plane 19 of the imaging device 50.

[0238] In practice, the sub-beam release plane 19, as a reference point for the distance to the beam focal position 71, is generally not of great significance. It would be more practical if the reference point could be arbitrarily chosen or calibrated. Therefore, it is advantageous to specify a functional relationship that directly describes the change in focal position. By applying the beam theorem and known imaging equations, the following functional relationship is obtained for the beam analysis device 10:

[0239] Δz = Δa c1 / (c2 + Δa c3)

[0240] The formula symbols c1, c2, and c3 are coefficients, which are introduced for the simplified representation of the formula.

[0241] For the case where the modulation device 20 is positioned in front of the imaging device 50 (see...) Figure 6The coefficients c1, c2, and c3 are given by the following formula:

[0242] c1 = z s 2

[0243] c2=k{s[1-(e / f)]+(e 2 / f)}

[0244] c3 = z s

[0245] For the case where the modulation device 20 is located behind the imaging device 50 (see...) Figure 7 The coefficients c1, c2, and c3 are given by the following formula:

[0246] c1 = [z s (fd)+d 2 ] 2

[0247] c2 = f 2 ks

[0248] c3=(fd)[z s (fd)+d] 2

[0249] The coefficients c1, c2, and c3 can be determined by setting at least three different known axial positions of the beam focus 71 and determining the corresponding changes in distance a Δa. The coefficients determined in this way can be stored as calibration data in the evaluation device 45, thereby allowing the evaluation device 45 to calculate the focus position change Δz for any distance change Δa.

[0250] Alternatively or additionally, the coefficients can be calculated directly from the geometric distance of the arrangement using the formula given above and stored in the evaluation device 45.

[0251] It should be noted that all axial distances, i.e., z s d, e, and s are distances along the optical axis 11. In the case of beam redirection (beam folding), therefore, the distance z... s , d, e, and s are therefore composed of their respective distances along the local optical axis 11, and are segmented if necessary. It should also be noted that if the beam is partially guided within the optical material, for example when guided by a beam splitter cube, the corresponding partial distances must be corrected by a factor that depends on the refractive index of the optical material.

[0252] In a variation of the embodiment of the beam analyzer 10, where the modulation device 20 is located behind the imaging device 50 (that is, behind at least one optical lens 51 in the beam direction), there exists a significant special case where the distance d from the principal plane of the imaging device 50 to the sub-beam release plane 19 is equal to the focal length f of the imaging device 50. In other words, the sub-beam release plane 19 is located at the image-side focal point of the imaging device 50. For such an embodiment of the beam analyzer 10, the coefficients of the functional relationship result in:

[0253] c1 = f 4

[0254] c2 = f 2 ks

[0255] c3 = 0

[0256] This leads to a particularly simple functional relationship, characterized by the fact that the change in distance Δa between beam points 92 and 93 is exactly proportional to the change in the position of the axial beam focal point Δz:

[0257] Δz=Δa f 2 / (ks)

[0258] This linear relationship simplifies the calibration of the device and enables high precision in determining the focal position.

[0259] A particularly advantageous aspect of this arrangement is that the calculation of the focal position change Δz does not require the absolute z-position of the beam focal point (z0). s ).

[0260] This feature or arrangement can be advantageously implemented in the form of an embodiment, wherein the distance between the imaging device 50 and the modulation device 20 is provided in any case, for example when the modulation device 20 is arranged in a folded beam path (see, for example...). Figure 12 and Figure 13 Therefore, this aspect of the invention can be further advantageously combined into an embodiment in which two folded beam paths are implemented, and no modulation device is present in one of the folded beam paths, thereby allowing simultaneous recording and determination of the original beam profile of the sample beam 70 (see...). Figure 17 and 18 In further combination with the axially adjustable mirror 64 in the beam path of the unmodulated beam 78, the entire beam defocus is recorded, and thus it is also possible to determine all geometric beam parameters (see [link]). Figures 19a to 19f ).

[0261] A first lateral direction 31 can be locally defined. In each case, it is (at least substantially) perpendicular to the local optical axis 11. In particular, it can be defined as a direction in a plane perpendicular to the local optical axis 11, in which at least two sub-beams 72, 73 have a distance relative to each other only through the distance k between the sub-apertures 32, 33.

[0262] The second lateral direction 37 can be locally defined. In each case, it is (at least substantially) perpendicular to the optical axis 11 and laterally to the (local) first lateral direction 31. The second lateral direction 37 can be changed once or more during global observation, for example by beam folding and / or beam redirection.

[0263] The sample bundle 70 can be the same as the energy bundle 77, especially if the sample bundle 70 is not formed by decoupling from the energy bundle.

[0264] In another improvement of the invention, at least one of the two sub-holes 32, 33 can be switched.

[0265] Particularly preferably, at least two sub-apertures 32, 33 can be switched. For example, the beam shaping device 12 can be configured to form an LCD screen device to form one or more switchable sub-apertures 32, 33. In this case, the plane of the LCD screen device can define the sub-beam release plane 19.

[0266] One or more of at least two sub-apertures 32, 33 of the beam shaping device 12 are preferably fixed. These sub-apertures 32, 33 can be formed, for example, by fixed screen openings and / or the (space-constrained) reflective surfaces of a mirror, and in this way, the transmission regions 21, 22 of the modulation device 20 can be formed. This achieves a simple, robust, reliable, and cost-effective implementation.

[0267] In a preferred embodiment, one or more of at least two sub-apertures 32, 33 of the beam shaping device 12 are variable. The variable sub-apertures 32, 33 can be implemented, for example, through multiple pixels of an LCD screen device and / or through screen openings with mechanically adjustable dimensions. The variable sub-apertures 32, 33 allow adaptation to current measurement conditions (e.g., light intensity, light distribution in the beam to be measured, wavelength, etc.).

[0268] The beam direction can be defined locally. The beam direction can be changed globally, for example, through beam folding and / or beam redirection. For example, the local beam direction can be defined by the direction of the local Poynting vector of sample beam 70.

[0269] In the direction of radiation propagation downstream of the sub-beam release plane 19, the local beam direction of sub-beams 72 and 73 can be defined by the direction of the local Poynting vector of the corresponding sub-beams 72 and 73.

[0270] In the direction of radiation propagation, downstream of the sub-beam release plane 19, the local (total) beam direction can be defined by averaging the local Poynting vectors of at least two sub-beams 72, 73. The magnitudes of the Poynting vectors of these sub-beams can be normalized before averaging. Alternatively, the local (total) beam direction can be defined by the Poynting vector of a virtual process of the sample beam without releasing the sub-beams.

[0271] For example, in operation, the local optical axis 11 can be defined by the desired local total beam direction.

[0272] One advantage of this invention is that the measurement principle of the beam analysis device is based on the determination of the positions of mutually separated beam points on the detector. For example, the positions of the beam points can be determined by calculating the centroid of the relevant intensity distribution (i.e., the intensity distribution at a first moment). The determination of the positions and their distances relative to each other is largely independent of, for example, the level of a constant signal background, which can be caused by scattered light and / or sensor noise. Therefore, this measurement principle is less prone to error than other methods, for example, based on determining the beam diameter (i.e., the intensity distribution at a second moment and its changes), because the determination of the second moment is relatively sensitive to changes in the background level.

[0273] Another significant advantage of this invention is that the determination of the axial position of the beam focal point is not affected by laser radiation or changes in the beam quality of the sample beam.

[0274] The axial position change of the beam focal point can be determined in near real-time, meaning that this determination requires only a fraction of the typical time constant of the focal position change caused by thermal focal shift. Therefore, the present invention can also provide signals for controlling the processing of laser materials during laser processing operations.

[0275] Possible embodiments are shown in the accompanying drawings and explained in the description of the drawings, wherein the invention is not limited to the forms of the embodiments shown. Various features or forms of the embodiments shown in the drawings can also be combined with each other to obtain other forms of embodiments of the invention.

[0276] For the purposes of this disclosure, the energy beam is preferably an electromagnetic radiation beam with a wavelength in the range of 0.1 micrometers to 10 micrometers, more preferably in the range of 0.3 micrometers to 3 micrometers, and even more particularly in the range of 0.3 micrometers to 1.5 micrometers.

[0277] For the purposes of this disclosure, the laser radiation is preferably electromagnetic radiation in the range of 0.3 micrometers to 1.5 micrometers and has a power of at least 1mW, particularly preferably at least 100W.

[0278] Reference Symbol List

[0279] 10 Beam Analysis Device

[0280] 11 Optical axis, local optical axis

[0281] 12 Beam Shaping Device

[0282] 14 Decoupling device

[0283] 15 Beam Decoupler

[0284] 16 Second beam decoupler

[0285] 19 Sub-beam release plane

[0286] 20 Modulation device

[0287] Transmission zones 21 and 22

[0288] 23, 24 Other transmission areas

[0289] 25 Blocking Zone

[0290] 31 First lateral direction

[0291] 32, 33 Zi Kong

[0292] 34, 35 and other sub-holes

[0293] 37 Second lateral direction

[0294] 39 Sensor plane

[0295] 40 detectors

[0296] 42 Second Detector

[0297] 43 Absorber device

[0298] 44 Absorber and / or power measuring device

[0299] 45 Evaluation Device

[0300] 49. The location of the imaging device and the principal plane of the imaging device.

[0301] 50 Imaging Device

[0302] 51 Optical Lenses

[0303] 52 Beam splitter device

[0304] 53, 54 Sub-beam deflection elements, such as wedges, prisms, or planar plates.

[0305] Other sub-beam deflection elements in 54b and 54c, such as wedges, prisms, or planar plates.

[0306] 55 Second beam splitter device

[0307] 56, 57 Sub-beam deflection elements, such as mirrors

[0308] 58, 59 Sub-beam deflection elements, such as mirrors

[0309] 60 beam folding device

[0310] 61 beam splitter

[0311] 62 Second beam splitter

[0312] 63 Another imaging device

[0313] 64 Reflectors

[0314] 66 Positioning device

[0315] 67 Another imaging device

[0316] 68 Deflecting Mirror

[0317] 69 Shutter mechanism

[0318] 70 sample bundles

[0319] 71 Beam Focus

[0320] 72, 73 sub-beams

[0321] 74, 75 Other sub-beams

[0322] 76 Energy Beam Focus

[0323] 77 Energy Beams

[0324] 78 Unmodulated beam

[0325] 79 Shaping Sample Bundles

[0326] 80 Intensity Distribution

[0327] 81 Intensity distribution in front of the modulation device

[0328] 82 Intensity distribution behind the modulation device

[0329] Intensity distribution on detector 83

[0330] 92, 93 beam points

[0331] 94, 95 Other beam points

[0332] 98. Beam spot of an unmodulated beam

[0333] 99 Far-field intensity distribution

[0334] 100 Processing Optical Devices

[0335] 110 Fiber end

[0336] 113 Collimator

[0337] 116 Focusing Optics

[0338] 120 Protective Glass

Claims

1. A beam analysis device (10) for determining the axial position of a beam focal point (71), characterized in that, The beam focus (71) is the focus (76) of the energy beam (77) of electromagnetic radiation, or the focus of the sample beam (70) decoupled from the energy beam (77), and includes a beam shaping device (12), a detector (40), and an evaluation device (45); wherein The beam shaping device (12) - It is configured to release two sub-beams (72, 73) from the energy beam (77) or from a sample beam (70) decoupled from the energy beam (77) in the sub-beam release plane (19), wherein The two sub-beams (72, 73) are the first sub-beam (72) and the second sub-beam (73), wherein The cross-sections of the two sub-beams (72, 73) within the sub-beam release plane (19) are defined by corresponding sub-apertures (32, 33), wherein The sub-holes (32, 33) are separated from each other, and the center points of the sub-holes (32, 33) are located at a distance k between them. The distance k between the sub-holes (32, 33) defines the first lateral direction (31). - is configured to form an intensity distribution (83) with beam points (92, 93) on the detector (40), and in order to form at least one beam point (92) from the first sub-beam (72) and at least one beam point (93) from the second sub-beam (73), the two sub-beams (72, 93) are... 73) Imaged onto the detector (40), and at least one of the two sub-beams (72, 73) is deflected and / or offset in the second lateral direction (37) so as to form a distance w between the two beam points (92, 93) on the detector (40) along the second lateral direction (37), wherein The second lateral direction (37) is perpendicularly aligned with the first lateral direction (31), and the first lateral direction (31) and the second lateral direction (37) are directions in a plane perpendicular to the corresponding local optical axis (11), and wherein The two beam points (92, 93) are at least one beam point (92) of the first sub-beam (72) and at least one beam point (93) of the second sub-beam (73), respectively; wherein The detector (40) -Including a light-radiation-sensitive, two-dimensional spatially resolved sensor, which is configured to convert the intensity distribution (83) illuminating the detector (40) into an electrical signal, and -The two sub-beams (72, 73) are arranged at a distance s behind the sub-beam release plane (19) along their propagation paths; and in The evaluation device (45) - The electrical signal is configured to process the detector (40), which represents the intensity distribution (83) on the detector (40). - is set to determine the distance 'a' between the positions of the two beam points (92, 93) on the detector (40) along the first lateral direction (31), and - It is set to determine the axial position of the beam focus (71) based on the distance a, and / or to determine the change in the axial position of the beam focus (71) based on the change in the distance a.

2. The beam analysis device (10) according to claim 1, characterized in that, The local optical axis (11) between the first lateral direction (31) and the sub-beam release plane (19) and the detector (40) is changed by beam folding and / or beam redirection.

3. The beam analysis device (10) according to claim 1, characterized in that, The beam shaping device (12) is configured to deflect and / or offset the two sub-beams (72, 73) relative to each other, wherein The difference between the deflection and / or shift of the two sub-beams (72, 73) is aligned along the second lateral direction (37) so as to form a distance w along the second lateral direction (37) between the two beam points (92, 93) on the detector (40).

4. The beam analysis apparatus (10) according to any one of claims 1-3, characterized in that, Includes a decoupling device (14), wherein The decoupling device (14) includes a beam decoupler (15) for decoupling the sample beam (70) from the energy beam (77).

5. The beam analysis device (10) according to claim 4, characterized in that, The beam decoupler (15) is a beam splitter device configured to decouple the radiation components of the energy beam (77) in the range of 0.01% to 5% as a sample beam (70) by reflection and / or transmission.

6. The beam analysis apparatus (10) according to any one of claims 1-3, characterized in that, The beam shaping device (12) includes an imaging device (50) having at least one optical lens (51) for imaging the two sub-beams (72, 73) onto the detector (40).

7. The beam analysis device (10) according to claim 6, characterized in that, The sub-beam release plane (19) is arranged at the image-side focal point of the imaging device (50).

8. The beam analysis device (10) according to claim 7, characterized in that, The evaluation device (45) is configured to determine the axial position of the beam focus (71) based on the distance a between the two beam points (92, 93) using a linear calculation rule, and / or determine the change in the axial position of the beam focus (71) based on the change in the distance a between the two beam points (92, 93).

9. The beam analysis apparatus (10) according to any one of claims 1-3, characterized in that, The evaluation device (45) is configured to determine the axial position of the beam focus (71) based on the distance a between the two beam points (92, 93) using at least a partially linear calculation rule, and / or to determine the change in the axial position of the beam focus (71) based on the change in the distance a between the two beam points (92, 93).

10. The beam analysis apparatus (10) according to any one of claims 1-3, characterized in that, The device includes a beam folding device (60), which comprises a beam splitter (61) and at least one reflector (64, 56, 57, 58, 59) and is arranged in the beam path in front of the detector (40), wherein... The at least one reflector (64, 56, 57, 58, 59) is arranged to reflect the radiation component leaving the beam splitter (61) back into the beam splitter (61), thereby forming a first folded beam path, and wherein The sub-beam release plane (19) of the beam shaping device (12) is located in the beam path in front of the beam folding device (60), or in the first folded beam path.

11. The beam analysis apparatus (10) according to claim 10, characterized in that, The beam folding device (60) further includes at least one second reflector (64, 56, 57, ...). 58, 59), among which The second reflector (64, 56, 57, 58, 59) is arranged to reflect another radiation component leaving the beam splitter (61) back into the beam splitter (61), thereby forming a second folded beam path.

12. The beam analysis apparatus (10) according to claim 11, characterized in that, The sub-beam release plane (19) of the beam shaping device (12) is located in the first folded beam path, wherein No sub-beam release is provided in the second folded beam path to guide the radiation component of the sample beam (70) or the energy beam (77) as an unmodulated beam (78) onto the detector (40), and wherein The evaluation device (45) is configured to determine the beam diameter and / or beam profile based on the intensity distribution of the beam spot (98) of the unmodulated beam (78) on the detector (40).

13. The beam analysis apparatus (10) according to claim 12, characterized in that, The reflector (64) is arranged such that it can be moved axially in the second folded beam path, and the position of the reflector (64) can be adjusted by the positioning device (66).

14. The beam analysis device (10) according to claim 1, characterized in that, The beam shaping device (12) includes a beam splitter device (52) having at least one sub-beam deflection element (53, 54, 56, 57, 58, 59) for deflecting and / or shifting one of the two sub-beams (72, 73) in a second lateral direction (37) to form a distance w along the second lateral direction (37) between two beam points (92, 93) on the detector (40).

15. The beam analysis apparatus (10) according to claim 14, characterized in that, The beam splitter device (52) includes at least two sub-beam deflection elements (53, 54, 56, ...). 57, 58, 59), used to deflect and / or shift the two sub-beams (72, 73) relative to each other, wherein The difference between the deflection and / or shift of the two sub-beams (72, 73) is aligned along the second lateral direction (37) so as to form a distance w along the second lateral direction (37) between the two beam points (92, 93) on the detector (40).

16. The beam analysis apparatus (10) according to claim 14 or 15, characterized in that, The beam splitter device (52) includes at least one wedge plate (53, 54) as a sub-beam deflection element, which is arranged in the direction of the two sub-beams (72, 73) in front of or behind one of the sub-apertures (32, 33) and is configured to deflect one of the two sub-beams (72, 73) released from the sub-apertures (32, 33) by an angle ranging from 0.02° to 6°.

17. The beam analysis apparatus (10) according to claim 14 or 15, characterized in that, The beam splitter device (52) includes at least one inclined plate (53, 54) or prism as a sub-beam deflection element, which is arranged in the direction of the two sub-beams (72, 73) in front of or behind one of the sub-apertures (32, 33) and is configured to deflect one of the two sub-beams (72, 73) released from the sub-apertures (32, 33) by an amount in the range of 0.05 mm to 3 mm.

18. The beam analysis apparatus (10) according to claim 14 or 15, characterized in that, The device includes a beam folding device (60), which comprises a beam splitter (61) and at least one reflector (64, 56, 57, 58, 59) and is arranged in the beam path in front of the detector (40), wherein... The at least one reflector (64, 56, 57, 58, 59) is arranged to reflect the radiation component leaving the beam splitter (61) back into the beam splitter (61), thereby forming a first folded beam path, and wherein The sub-beam release plane (19) of the beam shaping device (12) is located in the beam path in front of the beam folding device (60), or in the first folded beam path. The beam splitter device (52) is arranged within the first folded beam path and includes at least two mirrors (56, 57, 58, 59) as sub-beam deflection elements. -Arranged in the direction of the beam in front of or behind the corresponding one of the sub-apertures (32, 33), or the periphery of which itself forms the sub-aperture (32, 33), and - Set for back reflection of a corresponding one of the two sub-beams (72, 73), wherein the angular difference between the normal directions on the mirror surfaces of the mirrors (56, 57, 58, 59) is in the range of 0.01° to 3°, and wherein The difference between the normal directions on the mirror surfaces of the reflectors (56, 57, 58, 59) is aligned along the second transverse direction (37).

19. The beam analysis apparatus (10) according to any one of claims 1-3, characterized in that, The evaluation device (45) is further configured to determine the lateral position of the entire intensity distribution (83) with two beam points (92, 93) on the detector (40), and is configured to calculate the lateral position of the beam focus (71) of the sample beam (70) from the lateral position of the entire intensity distribution (83), and / or calculate the change in the lateral position of the beam focus (71) of the sample beam (70) based on the change in the lateral position of the entire intensity distribution (83), wherein the lateral position is the position relative to the first lateral direction (31) and the second lateral direction (37).

20. The beam analysis apparatus (10) according to claim 6, characterized in that, Further comprising a beam splitter (62) for separating the sample beam (70), another imaging device (63) including at least one optical lens, and a second detector (42), -The beam splitter (62) is arranged in the beam path in front of the sub-beam release plane (19) of the beam shaping device (12). - wherein the beam splitter (62) is arranged between the optical lens (51) of the imaging device (50) and the sub-beam release plane (19), and - wherein the other imaging device (63) is arranged between the beam splitter (62) and the second detector (42) for imaging a magnified image of the magnified beam spot (98) or the beam focus (71) onto the second detector (42).

21. The beam analysis apparatus (10) according to claim 20, characterized in that, The evaluation device (45) is configured to process the electrical signal generated by the second detector (42), and wherein The evaluation device (45) is configured to determine the beam diameter and / or focal diameter based on the intensity distribution on the second detector (42).

22. The beam analysis apparatus (10) according to claim 6, further comprising a beam splitter (62) for separating the sample beam (70), another imaging device (67) having at least one optical lens, and a second detector (42), -The beam splitter (62) is arranged in the beam path in front of the sub-beam release plane (19) of the beam shaping device (12). - wherein the beam splitter (62) is arranged between the optical lens (51) of the imaging device (50) and the sub-beam release plane (19). - wherein the other imaging device (67) is arranged between the beam splitter (62) and the second detector (42), - wherein the imaging device (50) and the other imaging device (67) together form a combined lens system, the combined lens system having an image-side focal plane, and - wherein the second detector (42) is arranged in the image-side focal plane of the combined lens system.

23. The beam analysis apparatus (10) according to claim 22, characterized in that, The evaluation device (45) is configured to process the electrical signal generated by the second detector (42), and wherein The evaluation device (45) is configured to determine the divergence angle based on the intensity distribution on the second detector (42).

24. The beam analysis apparatus (10) according to any one of claims 1-3, characterized in that, The beam shaping device (12) is configured such that when the axial position of the beam focus (71) changes, the positions of the two beam points (92, 93) on the detector (40) extend along two paths that are separated by a distance w from each other.

25. A system comprising a beam analysis device (10) according to any one of the preceding claims, and processing optics (100) for guiding and focusing the energy beam (77), wherein The processing optics (100) includes a decoupling device (14) for decoupling the sample beam (70) from the energy beam (77), and wherein The beam analysis device (10) can be connected to the processing optics (100) for receiving the decoupled sample beam (70).

26. A method for determining the axial position of a beam focal point (71), characterized in that, The beam focus (71) is either the focus (76) of the energy beam (77) of electromagnetic radiation, or the focus of the sample beam (70) decoupled from the energy beam (77), comprising the following steps: - In the sub-beam release plane (19), two sub-beams (72, 73) are released from the energy beam (77) or from the sample beam (70) decoupled from the energy beam (77), wherein The two sub-beams (72, 73) are the first sub-beam (72) and the second sub-beam (73), wherein The cross-sections of the two sub-beams (72, 73) within the sub-beam release plane (19) are defined by corresponding sub-apertures (32, 33), wherein The sub-holes (32, 33) are separated from each other, and the center points of the sub-holes (32, 33) are located at a distance k between them. The distance k between the sub-holes (32, 33) defines the first lateral direction (31), wherein -Guiding the two sub-beams (72, 73) onto a detector (40), which is positioned at a distance s behind the sub-beam release plane 19 along the propagation path of the two sub-beams (72, 73), includes: - The two sub-beams (72, 73) are imaged onto the detector (40) to form at least one beam point (92) from the first sub-beam (72) and at least one beam point (93) from the second sub-beam (73), thereby forming an intensity distribution (83) on the detector (40) comprising the two beam points (92, 93), wherein The two beam points (92, 93) are at least one beam point (92) of the first sub-beam (72) and at least one beam point (93) of the second sub-beam (73), respectively. - At least one of the two sub-beams (72, 73) is deflected and / or shifted in the second lateral direction (37), thereby forming a distance w along the second lateral direction (37) between the two beam points (92, 93) on the detector (40), wherein The second lateral direction (37) is oriented laterally to the first lateral direction (31). -The intensity distribution (83) illuminating the detector (40) is converted into an electrical signal by a light radiation-sensitive, two-dimensional spatially resolved sensor. -Process the electrical signal of the detector (40), which represents the intensity distribution (83) on the detector (40), - Determine the distance 'a' between the positions of the two beam points (92, 93) along the first lateral direction (31). - The axial position of the beam focus (71) is determined based on the distance a, or the change in the axial position of the beam focus (71) is determined based on the change in the distance a.

27. The method according to claim 26, characterized in that, include: - The two sub-beams (72, 73) are deflected and / or shifted relative to each other, wherein The difference between the deflection and / or shift of the two sub-beams (72, 73) is aligned along the second lateral direction (37), thereby forming a distance w along the second lateral direction (37) between the two beam points (92, 93) on the detector (40).

28. The method according to claim 26, characterized in that, This includes decoupling the sample beam (70) from the energy beam (77).

29. The method according to claim 28, characterized in that, The radiation components of the energy beam (77) in the range of 0.01% to 5% are decoupled into the sample beam (70) by reflection and / or transmission.

30. The method according to any one of claims 26-29, characterized in that, The two sub-beams (72, 73) are imaged onto the detector (40) by an imaging device (50) having at least one optical lens (51).

31. The method according to claim 30, characterized in that, The release of the two sub-beams (72, 73) occurs at the image-side focal point of the imaging device (50).

32. The method according to claim 31, characterized in that, The axial position of the beam focus (71) is determined based on the distance a between the two beam points (92, 93), or the change in the axial position of the beam focus (71) is determined based on the change in the distance a between the two beam points (92, 93), which is performed by a linear calculation rule.

33. The method according to any one of claims 26-29, characterized in that, The determination of the axial position of the beam focus (71) based on the distance a between the two beam points (92, 93), or the determination of the change in the axial position of the beam focus (71) based on the change in the distance a between the two beam points (92, 93), is performed by at least a partially linear calculation rule.

34. The method according to any one of claims 26-29, characterized in that, A first folded beam path is formed by a beam folding device (60), which includes a beam splitter (61) and at least one reflector (64, 56, 57, 58, 59), and the beam folding device (60) is arranged in front of the detector (40) by reflecting the radiation component leaving the beam splitter (61) back into the beam splitter (61) at the at least one reflector (64, 56, 57, 58, 59), and wherein The release of the two sub-beams (72, 73) occurs in the beam path in front of the beam folding device (60), or in the first folded beam path.

35. The method according to claim 34, characterized in that, A second folded beam path is formed by a beam folding device (60), which further includes at least one second mirror (64, 56, 57, 58, 59) to reflect another radiation component leaving the beam splitter (61) back into the beam splitter (61) at the at least one mirror (64, 56, 57, 58, 59).

36. The method according to claim 35, characterized in that, The release of the two sub-beams (72, 73) occurs in the first folded beam path, while in the second folded beam path, no sub-beam release occurs, and the radiation component is guided onto the detector (40) as an unmodulated beam (78), and wherein... The beam diameter and / or beam profile are determined based on the intensity distribution of the beam spot (98) of the unmodulated beam (78) on the detector (40).

37. The method according to claim 36, characterized in that, The axial position of the reflector (64) in the second folded beam path is changed by the positioning device (66), and the intensity distribution of the beam point (98) of the unmodulated beam (78) is recorded on the detector (40) at at least three different positions of the reflector (64), and at least one beam parameter of the sample beam (70) is determined according to the recorded intensity distribution.

38. The method according to any one of claims 26-29, characterized in that, This includes determining the lateral position of the entire intensity distribution (83) with two beam points (92, 93) on the detector (40), and calculating the lateral position of the beam focus (71) of the sample beam (70) from the lateral position of the entire intensity distribution (83), or calculating the change in the lateral position of the beam focus (71) of the sample beam (70) from the change in the lateral position of the entire intensity distribution (83), wherein the lateral position is the position relative to the direction in the corresponding plane perpendicular to the local optical axis (11).

39. The method according to claim 30, characterized in that, The following steps are involved: - The sample beam is separated by a beam splitter (62) located in the beam path behind the optical lens (51) of the imaging device (50) and in front of the plane of the sub-beam releaser (19). - The separated sample beam is imaged onto a second detector (42) by another imaging device (63) having at least one optical lens, the other imaging device (63) being arranged between the beam splitter (62) and the second detector (42) to form a magnified image of the beam spot (98) or beam focus (71) on the second detector (42), and - Determine the beam diameter or focal diameter based on the intensity distribution on the second detector (42).

40. The method according to claim 30, characterized in that, The following steps are involved: -The sample beam is separated by a beam splitter (62) located in the beam path behind the optical lens (51) of the imaging device (50) and in front of the sub-beam release plane (19). - The separated sample beam is guided to the second detector (42) by another imaging device (67) having at least one optical lens, the other imaging device (67) being arranged between the beam splitter (62) and the second detector (42) for forming a far-field beam distribution (99) on the second detector (42), wherein The imaging device (50) and the other imaging device (67) together form a combined lens system, the combined lens system having an image-side focal plane, and wherein... The second detector (42) is arranged in the image-side focal plane of the combined lens system, and - Determine the far-field beam diameter or divergence angle based on the intensity distribution on the second detector (42).

41. The method according to any one of claims 26-29, characterized in that, The energy beam (77) is focused by processing optical devices (100).

42. The method according to claim 41, characterized in that, The axial position of the determined beam focus (71), or the change of the axial position of the determined beam focus (71), is used to control the laser processing process.

43. The method according to any one of claims 26-29, characterized in that, When the axial position of the beam focus (71) changes, the positions of the two beam points (92, 93) on the detector (40) extend along two paths separated by a distance w.

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