Device and method for laser material processing and / or laser modification

Abstract

The present invention relates to a laser material processing device comprising a laser resonator, a scanning head, and a lens replacement device. The present invention also relates to a method for modifying the working distance during laser material processing.

Description

Technology Field

[0001] The present invention relates to a laser material processing device comprising a laser resonator, a scanning head, and a lens replacement device. The present invention also relates to a method for modifying the working distance during laser material processing. Background Technology

[0002] Laser material processing generally has the special advantage of being able to be performed dryly without the use of chemicals. Furthermore, it generally refers to a non-contact and / or force-free processing method that does not cause any material damage. Laser material processing is highly cost-effective due to its low operating costs.

[0003] In a laser material processing device that performs processing such as cutting or welding on a workpiece, processing is preferably carried out under optimal laser processing conditions, and results of high processing accuracy and processing quality can be achieved at high speed.

[0004] Several factors determine the desirability of a laser processing device. These include accuracy, quality, availability, flexibility, and throughput. Throughput is a very important consideration because it has a direct impact on the cost of machining on a per-piece basis. System throughput is a function of various factors, including material removal rate, workpiece, and laser beam positioning speed.

[0005] To change the working distance, particularly when processing components with complex geometries, lenses arranged between the component and the scanning head (F-theta lenses, also known as telecentric lenses, flat-top lenses, or top-hat lenses) are currently used.

[0006] An F-Theta lens—also known as a scan lens or flat-field lens—is a lens system used in numerous scanning applications. It is inserted into the beam path after the scanning head to perform various tasks. First, the lens focuses the laser beam to a focal point, and second, it ensures that this focal point always remains on the lens's working plane during scanning. Furthermore, the position on the working plane follows the F-Theta condition approximately, meaning that the scan length (image height) is roughly proportional to the set scan angle. The F-Theta lens also serves to keep the focal plane of the focused laser beam constant during movement, for example, within a marking field. If a standard lens were used, the focal point would shift out of the focal plane as soon as the laser beam leaves the center of the marking field, because the distance from the lens to the marking field increases.

[0007] The key quality characteristics of a good F-theta lens include low image field curvature, a large image field, and good and homogeneous focus quality across the entire image field. An important criterion here is whether the focus is diffraction-limited. Since such F-theta lenses contain multiple lenses, this can lead to various problems. Examples include so-called internal ghosting and external ghosting.

[0008] Internal ghost

[0009] Ghosting or back reflection is caused by the reflection of light from the lens or the protective glass surface behind it. Internal ghosting is characterized by focusing on the lens elements within the lens.

[0010] The anti-reflective coating optimizes the transition from optically less dense intermediate air to optically more dense intermediate glass, so that the loss at the surfaces is only about 0.2% instead of the original 4%. Despite the low absorption loss, the use of the laser often exceeds the destruction threshold, causing damage to the affected lens element.

[0011] Most lenses consist of two to six lenses. The solution is to design the lenses in such a way that there is no back reflection near the lenses. These "ghost-free" lenses are highly recommended for high-power lasers, medium-power lasers (kilowatt range), and short-pulse lasers. For short-pulse compatibility, ghost-free lenses are constructed of glass with a low temperature coefficient (most importantly, quartz glass), which is not cemented.

[0012] External ghost

[0013] Ghost is back reflection from the lens surface or protective glass. High-power lasers can damage optical elements at the focal point of the back reflection. In the case of internal back reflection, the focal point lies on the lens surface inside the lens. These lenses are generally not suitable for high-power lasers.

[0014] Conversely, external ghosting is located outside the lens on the object side. In this case, a high-power laser can be safely used. However, the distance between the lens and the rest of the setup must be carefully selected. If the focus of the ghosting is on an upstream optical element (typically the mirror of the scanning head), damage may occur there.

[0015] Therefore, F-theta lenses are complex, expensive to manufacture, and relatively heavy, and the purchase price is high, especially in the UV or UVC range. means of solving the problem

[0016] Accordingly, one objective of the present invention is to provide a method for modifying the working distance in laser material processing that can be performed reliably and cost-effectively using simple means.

[0017] In addition, one objective of the present invention is to provide a laser material processing device in which the working distance can be reliably and cost-effectively adjusted and changed.

[0018] The working distance of a laser system is typically defined as the physical distance from the last optical element (usually a focusing lens) to the object or surface on which the laser is focused. In certain applications, e.g., medical lasers, the working distance must be as small as possible, e.g., for cutting applications (e.g., cutting glass), whereas in other applications, the working distance range must be as large as possible, e.g., for annealing marks on metal or color changes on plastics or paints. The working distance (A) is defined as the distance between the central axis of the entrance opening and the working plane. (A) is also determined by the focal length and mounting position of the F-theta lens (if present). In a prefocus system, the distance (A) is determined by the dynamic focusing unit at the zero position.

[0019] The problem is solved by a laser material processing device according to the present invention for processing components having complex component geometry. Advantageous embodiments of the present invention are likewise described in the dependent claims.

[0020] A laser material processing device according to the present invention for processing a component having a complex component geometry comprises a laser resonator, a scanning head for deflecting laser radiation, and a lens replacement device.

[0021] Laser resonators or beam sources within the meaning of this patent specification include any type of (beam) source, such as X-ray devices, EUV beam sources, etc., that generate radiation within a wavelength range of 0.01 nm to 400 nm. Additionally, the term laser resonator as used herein also includes an optical guide and / or coupling window for coupling radiation within a wavelength range of 0.01 nm to 400 nm into a laser material processing device, and the beam source is arranged outside the laser material processing device and is therefore not part of the laser material processing device.

[0022] For the purposes of this specification, a scanning head is any device for deflecting a suitable laser beam designed to guide the laser beam to different locations of a component to be processed for the purpose of processing. These include, for example, (laser) beam deflection units, such as acousto-optic deflectors, polygon mirrors, or scanning heads (galvanic scanners).

[0023] For the purposes of this specification, the term laser material processing includes any processing of a material in which the structure of the material is altered by the action of a laser. This also includes structural changes in the processed material that result in a flying object being unable to fly. Accordingly, a laser material processing device within the meaning of this specification is any device in which laser material processing can be performed using laser radiation.

[0024] Within the meaning of the present invention, a component having a complex component geometry is a component having a plurality of surfaces. The surfaces of the component may be composed of planar or curved sections and / or may have planar and / or circular or spherical interfaces having any angle with respect to each other. Additionally, the component may have undercuts and / or cavities. In particular, such a component requires different working distances for the laser radiation of a laser resonator. The working distance of a laser material processing device is typically defined as the physical distance from the last optical element (here, a scanning head) to the object or surface where the laser radiation is focused.

[0025] For the purposes of this specification, a scanning head is any deflection unit suitable for deflecting a laser beam in one or more directions and / or directing it to another part of the component to be processed. These include, for example, a scanning head, a polygonal scanner, acousto-optic deflectors, and / or one or more galvanometer scanners. A galvanometer scanner is a highly dynamic electro-optical component that uses a rotatable, low-inertia mirror to position the laser beam with high accuracy and repeatability, and typically uses two galvanometer scanners to deflect the laser beam in two directions.

[0026] According to the present invention, the lens replacement device is preferably arranged between the laser resonator and the scanning head. Alternatively, the lens replacement device may also be positioned behind the scanning head.

[0027] In an alternative embodiment of the present invention, the use of an F-theta lens arranged between the scanning head and the component and typically having multiple lenses is eliminated. Accordingly, the laser material processing device is inexpensive, small, light, and convenient, while the processing of the component is precise and rapid.

[0028] Laser material processing can be performed on numerous different workpieces using different lasers that affect various processes. Examples of laser material processing include laser sintering, stereolithography, laser beam bending and laser-assisted bending, laser cutting and drilling, laser ablation, laser trimming, laser beam welding, laser cladding welding and soldering, laser marking, laser spraying and laser beam evaporation, laser polishing, laser (micro)structuring, and annealing marking.

[0029] In an optional embodiment of the present invention, the laser resonator has a nonlinear optical medium (FV) for frequency doubling or multiplication.

[0030] In a further developmental example of the present invention, the laser material processing device is suitable for processing a component by structurally altering the material of the component. This includes material processing methods such as marking, laser welding, laser recording, laser engraving, and laser cutting. In an optional embodiment, the laser material processing device is suitable for polishing the component.

[0031] In a further embodiment of the present invention, the laser resonator generates laser resonator radiation having a wavelength of 0.01 nm to 400 nm, preferably 10 nm to 315 nm, particularly preferably 100 nm to 280 nm, and particularly preferably 200 nm to 280 nm. The laser medium of the laser resonator includes all known laser types, such as solid-state lasers, gas lasers (also excimer lasers, metal vapor lasers), dye lasers, or free-electron lasers. The laser resonator can be operated in pulsed or continuous wave mode. This enables a wide range of laser material processing methods.

[0032] In an advantageous embodiment of the present invention, the lens replacement device is suitable for changing the maximum focal length of the laser material processing device in the range of 1,000 mm to 100,000 mm.

[0033] In an advantageous embodiment of the present invention, the lens replacement device is suitable for changing the minimum focal length of the laser material processing device in the range of 5 mm to 50 mm.

[0034] In an advantageous embodiment of the present invention, the lens replacement device is suitable for changing the focal length of the laser material processing device to a range of 5 mm to 100,000 mm, preferably 20 mm to 10,000 mm, and particularly preferably 50 mm to 1,000 mm.

[0035] In another embodiment of the present invention, the lens replacement device has one or more lenses. In particular, the lenses optionally have different focal lengths. This allows for different working distances.

[0036] In a further development example of the present invention, the working distance may be modified to a range of 1 mm to 15 mm, 5 mm to 500 mm, 10 mm to 1000 mm, 15 mm to 750 mm, 25 mm to 600 mm, 35 mm to 450 mm, 50 mm to 800 mm, 75 mm to 700 mm, or 100 mm to 1200 mm and / or exceeding 5 km.

[0037] As defined herein, lenses are all optical elements in which the focal length of the optical system can be changed. Accordingly, the term lens as used herein also includes an asphere, which creates a focusing option with very small size and low weight by enabling diffraction-limited focusing without requiring a complete lens system. It also includes multifocal lenses or small lens systems, such as achromats, which usually consist of only two lenses, or achromats preferably having an air gap, as well as so-called microlenses. It also includes a mirror for adjusting the output of a laser. Furthermore, so-called holographic optical elements (HOEs) are also included, and these optical elements may be of various properties (such as mirrors, directional diffusers, as well as lenses). When using HOEs, for example, "continuous" focus transitions can be generated (different focal lengths can be changed, and the change occurs in the sense of a smooth transition rather than in a "jerky" or "jumpy" manner). Additionally, when using HOEs, individual "beam geometries" can be reproduced on the workpiece. Generally, a round or nearly round laser beam can be followed by, for example, a square beam, or the laser beam can take on a more complex geometry, which can also be composed of various individual structures, ranging from photorealistic representations.

[0038] In a further embodiment of the present invention, one or more lenses of the lens replacement device may be movably positioned with respect to the beam path. In a further embodiment of the present invention, one or more lenses of the lens replacement device may be positioned within the beam path. Different working distances are possible by arranging different lenses in the beam path at different times.

[0039] In a further embodiment of the present invention, one or more lenses may be moved by rotation and / or translation. The lenses are arranged on or in a lens replacement device in such a manner that the lenses and / or a combination of multiple lenses (lens system) can be arranged in a beam path by rotation and / or translation.

[0040] In a further embodiment of the present invention, the lens replacement device and the laser resonator and / or scanning head are arranged to be movable relative to each other. In another aspect of the present invention, the lens replacement device and the laser resonator and / or scanning head are movable relative to each other by translational movement. In a further embodiment of the present invention, translational movement occurs parallel to the beam path. The laser resonator may be movable or the lens replacement device may be movable. The only relevant aspect of the present invention is that the laser resonator and the lens replacement device may perform relative movement relative to each other parallel to the beam path. By the relative movement of the laser resonator and / or laser beam and the lens replacement device parallel to the beam path, the focus on the component is adjusted to achieve a small change in working distance (An) (<50 mm).

[0041] The objective is also achieved by the method of the present invention for modifying the working distance during laser material processing. Advantageous embodiments of the present invention are likewise described in the dependent claims.

[0042] A method according to the present invention for modifying the working distance during laser material processing has five steps. In the first step, laser radiation is generated in a laser resonator. The laser medium of the laser resonator includes all known laser types, such as solid-state lasers, gas lasers (also excimer lasers, metal vapor lasers), dye lasers, or free electron lasers. The laser resonator can be operated in pulsed or continuous wave mode. This enables a wide range of laser material processing methods.

[0043] In the second step, the laser resonator radiation is coupled out from the laser resonator. In the third step, the laser beam generated from the laser resonator beam is deflected onto the component to be processed, and the first laser radiation has a first working distance.

[0044] In the fourth step, the first working distance is changed to the second working distance, and the change in working distance is performed by exchanging the first lens and the second lens placed in the beam path using a lens replacement device arranged between the laser resonator and the scanning head. The lens replacement device has two or more lenses that can be arranged alternately or in combination in the beam path by the lens replacement device so that a combination of lenses and / or multiple lenses (lens systems) is arranged in the beam path at any given time.

[0045] In step 5, laser radiation is deflected onto the component to be processed at a second working distance, wherein the first and second working distances differ by at least 50 mm. In a preferred embodiment, the first and second working distances differ by at least 100 mm, more preferably at least 200 mm, and even more preferably at least 1000 mm.

[0046] The laser radiation is selectively deflected by a scanning head, which acts as a galvanometer scanner. A lens replacement device is positioned between the laser resonator and the scanning head. This eliminates the need for F-theta lenses, which are typically located between the scanning head and the component and generally have multiple lenses. Consequently, the laser material processing device is inexpensive, compact, lightweight, and convenient, while the processing of the component is precise and rapid.

[0047] In a further embodiment of the present invention, the laser resonator generates laser resonator radiation having a wavelength of 0.01 nm to 400 nm, preferably 10 nm to 315 nm, particularly preferably 100 nm to 280 nm, and particularly preferably 200 nm to 280 nm. The laser medium of the laser resonator includes all known laser types, such as solid-state lasers, gas lasers (also excimer lasers, metal vapor lasers), dye lasers, or free-electron lasers. The laser resonator can be operated in pulsed or continuous wave mode. This enables a wide range of laser material processing methods.

[0048] In a further embodiment of the present invention, the focal length of the laser resonator radiation is changed by a lens changing device to generate a first laser radiation. Using the lens changing device, a first lens having a first focal length can be positioned within the beam path. In a further embodiment of the present invention, the lens changing device for changing the laser resonator radiation having a laser resonator focal length into a first laser radiation having a first focal length positions a first lens in the beam path. The lens changing device has two or more lenses that can be arranged in the beam path by the lens changing device such that a combination of lenses and / or a plurality of lenses (lens systems) is arranged in the beam path at any given time.

[0049] In a further embodiment of the present invention, a lens replacement device for changing a laser resonator radiation having a laser resonator focal length and / or a first laser radiation having a first focal length into a second laser radiation having a second focal length positions a second lens in the beam path. The second focal length is different from the first focal length, and thus the working distances of the first and second lenses are also different from each other.

[0050] In a further development example of the present invention, the working distance is changed in the range of 5 mm to 500 mm, 10 mm to 1000 mm, 15 mm to 750 mm, 25 mm to 600 mm, 35 mm to 450 mm, 50 mm to 800 mm, 75 mm to 700 mm, or 100 mm to 1200 mm. Thus, the focus can be changed almost continuously from just a few mm to 100 mm, several meters, and even further distances.

[0051] In a further developmental example of the present invention, when the second lens is positioned in the beam path, the first lens is removed from the beam path. Therefore, only one lens is positioned in the beam path at any given time.

[0052] In a further embodiment of the present invention, positioning is achieved by rotation and / or translation. Lenses are arranged on or in a lens replacement device in such a manner that the lenses can be arranged in the beam path by rotation and / or translation.

[0053] In a further embodiment of the present invention, the lens replacement device comprises one or more lenses movably arranged with respect to a beam path. Optionally, all lenses and / or combinations of lenses arranged on the lens replacement device have different focal lengths. This enables a wide variety of different working distances. In addition to different focal lengths, the lenses may also differ in other characteristics, such as lenses having special nanostructures.

[0054] In another aspect of the present invention, the lens replacement device performs translational movement in relation to the position of the laser resonator and / or the scanning head. In a further development of the present invention, the translational movement occurs parallel to the beam path. The laser resonator may be movable, or the lens replacement device may be movable. The only relevant aspect of the present invention is that the laser resonator and the lens replacement device may perform relative movement relative to each other parallel to the beam path. By the relative movement of the laser resonator and the lens replacement device parallel to the beam path, the focus on the component is adjusted to achieve a small change in the working distance (An).

[0055] In a further embodiment of the present invention, the first and / or second laser radiation is deflected by a scanning head. Optionally, the scanning head may be a galvanometer scanner. A galvanometer scanner is a highly dynamic electro-optical component that uses a rotatable, low-inertia mirror to position the laser beam with high accuracy and repeatability. Brief explanation of the drawing

[0056] An exemplary embodiment of the laser material processing device and method according to the present invention for modifying the working distance is schematically illustrated in a simplified form in the drawings and is described in more detail in the following description. especially, Figure 1 illustrates a laser material processing device. FIG. 2 illustrates a laser material processing device equipped with a lens replacement device having four lenses. FIG. 3 illustrates a laser material processing device with laser drilling of a component. FIG. 4a illustrates a laser material processing device in which laser resonators are arranged movably translationally. FIG. 4b illustrates a laser material processing device in which lens replacement devices are arranged to be translationally movable. FIG. 4c illustrates a laser material processing device in which a lens replacement device is arranged to be translationally movable and an additional optical device is located in front of the lens replacement device. FIG. 4d illustrates a laser material processing device in which a lens replacement device is arranged to be translationally movable and an additional optical device is located at the rear of the lens replacement device. FIG. 5 illustrates a laser material processing device having two lens replacement devices arranged to be movable parallel to each other. FIG. 6 illustrates a laser material processing device in which two lens replacement devices are arranged to be movable relative to each other. FIG. 7a illustrates a lens replacement device of an exemplary embodiment. FIG. 7b illustrates a lens replacement device of an exemplary embodiment. FIG. 7c illustrates a lens replacement device of an exemplary embodiment. Specific details for implementing the invention

[0057] FIG. 1 illustrates an exemplary embodiment of a laser material processing device (LMB). The laser material processing device (LMB) has a laser resonator (LR). The laser resonator (LR) has a laser crystal (LK), which is an Nd-doped crystal in this embodiment. In principle, other laser media such as gas lasers, dye lasers, diode lasers, excimer lasers, etc. are also possible. The laser resonator (LR) additionally has two end mirrors, one of which is partially transparent to couple out laser resonator radiation (LSR), as well as a nonlinear optical medium (FV) for frequency doubling. The laser resonator (LR) itself is diode-pumped. Due to frequency doubling by the nonlinear optical medium (FV), the laser resonator (LR) emits laser resonator radiation (LSR) having a wavelength of 532 nm and a laser resonator focal length. The laser resonator (LR) generates laser resonator radiation (LSR) having a wavelength of 0.01 nm to 400 nm, preferably 10 nm to 315 nm, particularly preferably 100 nm to 280 nm, and particularly preferably 200 nm to 280 nm.

[0058] In all exemplary embodiments described herein, the type of material processing of the component is abrasive and / or results in a structural change of the material. This includes material processing methods such as marking (e.g., annealing marking or creating a color change), laser welding, recording, engraving, and cutting.

[0059] Laser resonator radiation (LSR) travels along a beam path toward a component (BT) having a complex geometry, and the laser resonator radiation (LSR) is deflected by a movable scanning head (SK) to process the component (BT). The SK scanning head is a galvanometer scanner. The galvanometer scanner is a highly dynamic electro-optical component that uses a rotatable, low-inertia mirror to position the laser beam with high accuracy and repeatability.

[0060] The lens replacement device (LWV) is arranged between the laser resonator (LR) and the scanning head (SK), and in this embodiment, has only one lens (L1) with a fixed focal length. As a result, the laser material processing device (LMB) has only one working distance (A1), but at least two different working distances (A1, A2) will be required to efficiently process the component (BT).

[0061] FIG. 2 illustrates a laser material processing device (LMB) of an exemplary embodiment according to the present invention. The laser material processing device (LMB) corresponds to the one already described in the preceding exemplary embodiment (see FIG. 1), except that a lens replacement device (LWV) is arranged between a laser resonator (LR) and a scanning head (SK), and in this exemplary embodiment, the lens replacement device (LWV) has four lenses (L1, L2, L3, L4) having different focal lengths (BWn). Lens (L1) has a focal length, lens (L2) has a focal length (L2), lens (L3) has a focal length (L3), and lens (L4) has a focal length (L4). In addition to different focal lengths, the lenses may also differ in other characteristics, such as lenses having special nanostructures.

[0062] To modify the working distances (A1, A2), laser resonator radiation (LSR) is generated from the laser resonator (LR) and coupled out. At a first time point, a first lens (L1) is aligned in the beam path and generates a first laser radiation (LS1) having a first focal length, which is directed onto the component (BT) at the first working distance (A1) by the scanning head (SK). At a second time point, the lens replacement device (LWV) is moved in such a way that the lenses (Ln) fixed thereto move perpendicular to the beam path of the laser resonator radiation (LSR). This removes the first lens (L1) from the beam path and positions the second lens (L2) in the beam path. Through this second lens (L2), the laser material processing device (LMB) generates a second laser radiation (LS2) having a second focal length, which is directed onto the component (BT) at the second working distance (A2) by the scanning head (SK).

[0063] At the third point in time, the lens replacement device (LWV) is moved in such a way that the lenses (Ln) fixed thereto move perpendicularly to the beam path of the laser resonator radiation (LSR). This removes the second lens (L2) from the beam path and positions the third lens (L3) in the beam path. Through this third lens (L3), the laser material processing device (LMB) generates a third laser radiation (LS3) having a third focal length (BW3), which is directed onto the component (BT) by the scanning head (SK) at a third working distance (A3).

[0064] At the fourth time point, the lens replacement device (LWV) is moved in such a way that the lenses (Ln) fixed thereto move perpendicularly to the beam path of the laser resonator radiation (LSR). This removes the third lens (L3) from the beam path and positions the fourth lens (L4) in the beam path. Through this fourth lens (L4), the laser material processing device (LMB) generates a fourth laser radiation (LS4) having a fourth focal length (BW4), which is directed onto the component (BT) by the scanning head (SK) at a fourth working distance (A4).

[0065] FIG. 3 illustrates a laser material processing device (LMB) of a further exemplary embodiment according to the present invention. The laser material processing device (LMB) corresponds to that of the preceding exemplary embodiment (see FIG. 2), in which a component (BT) is processed using a laser drilling process. The bore to be created is arranged parallel to the beam path of the laser material processing device (LMB) and requires a plurality of working distances (A1, A2) realized by a lens replacement device (LWV). The working distances (A1, A2) are changed using the method described in FIG. 2.

[0066] FIG. 4 illustrates a laser material processing device (LMB) of an exemplary embodiment according to the present invention. The laser material processing device (LMB) corresponds to that described in the preceding exemplary embodiment (see FIG. 2). In this embodiment, the laser resonator (LR) and the lens replacement device (LWV) are arranged to be movable relative to each other parallel to the beam path (Figs. 4a and 4b). The laser resonator (LR) may be movable (Fig. 4a) or the lens replacement device (LWV) may be movable (Fig. 4b). The only relevant aspect of the present invention is that the laser resonator (LR) and the lens replacement device (LWV) may perform relative movement relative to each other parallel to the beam path. The working distance (A1, A2) is changed using the method described in FIG. 2, and additionally, during the processing of the component (BT), the relative translational movement of the laser resonator (LR) and / or the lens replacement device (LWV) is performed with the laser resonator (LR) activated. By relative movement of the laser resonator (LR) and the lens replacement device (LWV) parallel to the beam path, the focus on the component (BT) is adjusted to achieve further changes in working distances (A1, A2). Additionally, this movement can be used to refocus or fine-tune the focus.

[0067] Alternatively, an additional optical device (Lx) may be arranged adjacent to the lens replacement device (LWV) and may be movable relative to it, which is suitable for performing relative movement relative to each other parallel to the beam path (see FIG. 4c and FIG. 4d). This additional optical device may be, for example, another lens, another lens system and / or another optical device suitable for changing the focus of the laser beam. The additional optical device (Lx) may be positioned between the laser resonator (LR) and the lens replacement device (LWV), or between the lens replacement device (LWV) and the scanning head (SK). The working distance (A1, A2) is changed using the method described in FIG. 2, and additionally, during the processing of the component (BT), relative translational movement of the additional optical device (Lx) is performed while the laser resonator (LR) is active. By moving the additional optical device (Lx) parallel to the beam path, the focus on the component (BT) is adjusted in such a way that additional changes in the working distance (A1, A2) are achieved. Additionally, this movement can be used to refocus or fine-tune the focus.

[0068] The relative movement of the laser resonator (LR), lens replacement device (LWV), and / or additional optical device (Lx) described in FIGS. 4a through 4d is preferably performed by a piezoelectric drive in a design advantageous (because it is fast and precise down to the nanometer range). The piezoelectric drive can move rapidly and has nanometer-range repeatability / positional accuracy. This is important for precise and repeatable positioning of individual optical elements, and therefore is also important for correspondingly precise and fast (micro-)material processing. When performing a laser drilling operation, for example, on glass several centimeters thick, the focus can be adjusted by moving the laser resonator (LR), the lens replacement device (LWV), and / or additional optical device (Lx) through relative movement so that laser processing can be performed with the focus maintained over a longer path length without replacing the lens currently used in the lens replacement device (LWV), or by moving the individual optical elements of the lens replacement device (LWV), for example, L1 = 4c or 4d) together.

[0069] FIG. 5 illustrates a laser material processing device (LMB) of a further exemplary embodiment according to the present invention. The laser material processing device (LMB) corresponds to that described in the prior embodiment (see FIG. 4d). In addition to a first lens replacement device (LWV1) having four lenses (L1.1, L2.1, L3.1, L4.1), a second lens replacement device (LWV2) having four lenses (L1.2, L2.2, L3.2, L4.2) is arranged here between the first lens replacement device (LWV) and the scanning head (SK). Both lens replacement devices (LWV1, LWV2) are movable. Both lens replacement devices (LWV1, LWV2) are arranged to be movable relative to each other with respect to the laser resonator (LR) and parallel to the beam path. With the help of two individually movable lens replacement devices (LWV1, LWV2), the lenses (L1.1, L2.1, L3.1, L4.1, L1.2, L2.2, L3.2, L4.2) of the individual lens replacement devices (LWV1, LWV2) can each be positioned in the beam path. This allows multiple lenses (L1.1, L2.1, L3.1, L4.1, L1.2, L2.2, L3.2, L4.2) to be combined to set different working distances (A1, A2).

[0070] During the processing of the component (BT), the relative translational movement of the lens replacement devices (LWV1, LWV2) is performed with the laser resonator (LR) activated. By the relative movement of the lens replacement devices (LWV1, LWV2) parallel to the beam path, the focus on the component (BT) is adjusted to achieve a further change in the working distance (A1, A2). Additionally, this movement can be used to refocus or fine-tune the focus.

[0071] Additionally, in this embodiment, an additional optical device (Lx) is arranged adjacent to the lens replacement device (LWV2) and movably parallel to the beam path. This additional optical device may be, for example, another optical element such as another lens, another lens system and / or a mirror suitable for changing the focus of the laser beam. The additional optical device (Lx) may be arranged between the laser resonator (LR) and the first lens replacement device (LWV1), between two lens replacement devices (LW1, LW2), or between the second lens replacement device (LWV2) and the scanning head (SK). Alternatively, multiple additional optical devices may be used.

[0072] FIG. 6 illustrates an embodiment having a setup similar to FIG. 5. The essential difference herein is that the lenses (L1.2, L2.2, L3.2, L4.2) of the second lens replacement device (LWV2) are designed as mirrors, which causes the laser beam (LS) to be additionally deflected. Coated mirrors have a higher damage threshold for high-energy radiation than conventional or coated lenses. This results in a longer service life in operation.

[0073] In an alternative embodiment of the present invention, the lens or mirror has a continuously changing refractive index similar to a progressive lens. This enables the focus to be continuously shifted by moving the lens changing device (LWV).

[0074] The relative movement of the laser resonator (LR), lens replacement device (LWV), and / or additional optical device (Lx) described in FIGS. 4a through 4d, FIGS. 5, and FIGS. 6 is preferably performed by a design advantageous to a piezoelectric drive (since it is fast and accurate down to the nanometer range). The piezoelectric drive can move rapidly and has nanometer-range repeatability / positional accuracy. This is important for precise and repeatable positioning of individual optical elements, and therefore is also important for correspondingly precise and fast (micro-)material processing. When performing a laser drilling operation, for example, on glass several centimeters thick, the focus can be adjusted by moving the laser resonator (LR), the lens replacement device (LWV), and / or additional optical device (Lx) via relative movement, or by moving the individual optical elements of the lens replacement device (LWV), e.g., L1 = 4c or 4d), together, so that laser processing can be performed with the focus maintained over a longer path length without replacing the lens currently used in the lens replacement device (LWV). It is advantageous to drill from bottom to top.

[0075] FIG. 7 illustrates embodiments of a lens replacement device (LWV). Examples illustrate lens replacement devices (LWVs) arranged parallel to a beam path. Each lens replacement device (LWV) has six lenses (L1, L2, L3, L4, L5, L6), each having a different focal length. According to the present invention, the number of lenses (L1, L2, L3, L4, L5, L6) arranged in the lens replacement device (LWV) is not limited, and thus any number of different working lengths can be made possible. Individual lenses (L1, L2, L3, L4, L5, L6) are arranged on a carrier element (TE) of the lens replacement device (LWV). Thus, the laser material processing device (LMB) according to the present invention can be used in a component (BT) having different complex geometries. The carrier element serves to hold various lenses and / or couple with a motor or actuator to perform lens movement.

[0076] FIG. 7a illustrates an advantageous variation of a lens replacement device (LWV) having six lenses (L1, L2, L3, L4, L5, L6) arranged coaxially on a carrier element (TE) of the lens replacement device (LWV). To change the working distance (A1, A2), the lens replacement device (LWV) performs rotational motion around the central axis of the lens replacement device (LWV) such that one of the six lenses (L1, L2, L3, L4, L5, L6) is positioned within the beam path at any given time.

[0077] FIG. 7b illustrates a lens replacement device (LWV) in which six lenses (L1, L2, L3, L4, L5, L6) are arranged side by side on the carrier element (TE) of the lens replacement device (LWV). To change the working distance (A1, A2), the lens replacement device (LWV) is translated perpendicularly to the beam path so that one of the six lenses (L1, L2, L3, L4, L5, L6) is aligned in the beam path at any given time.

[0078] FIG. 7c illustrates a lens replacement device (LWV) in which six lenses (L1, L2, L3, L4, L5, L6) are arranged side by side on a carrier element (TE) of the lens replacement device (LWV). In this exemplary embodiment, the lenses (L1, L2, L3, L4, L5, L6) are not circular as in all prior embodiments (see FIG. 1 through 7b), but have straight side edges with circular segments at the top and bottom. This advantageous design of the lenses (L1, L2, L3, L4, L5, L6) allows for the arrangement of a greater number of lenses (L1, L2, L3, L4, L5, L6) per unit length on the lens replacement device (LWV) than when the lenses (L1, L2, L3, L4, L5, L6) are designed to be circular. In addition, faster lens replacement is possible, and due to lower weight, less powerful actuators can also be used for lens replacement. To modify the working distance (A1, A2), the lens replacement device (LWV) is translated perpendicularly to the beam path so that one of the six lenses (L1, L2, L3, L4, L5, L6) is aligned in the beam path at any given time.

[0079] In another exemplary embodiment, the working distance of the laser material processing device is dynamically changed. The change in working distance occurs in a time of less than 500 ms, preferably less than 200 ms, particularly preferably less than 100 ms, and particularly preferably less than 10 ms. This is achieved by the fact that the lens replacement device does not need to refocus the laser beam when replacing lenses arranged in the beam path. This enables, for example, laser marking, microstructuring, etc., to be applied to a three-dimensional body having different working distances for the laser material processing device due to its geometric shape.

[0080] In other embodiments, different optical devices are selected and / or exchanged and / or combined or substituted with one another, thereby creating different arrangements (e.g., expansion factors combined with different focusing lenses). It should be emphasized that, in addition to dynamic focusing (Lx = for different (height) planes in the drawing), multiple lens replacement devices (LWV1, LWV2) are also used simultaneously to enable the use of multiple combinations of optical elements (particularly lenses). This can achieve a wide variety of optical effects (e.g., effects similar to a camera zoom lens by rapidly changing the combination of different optical elements, different working areas (working area size / marking field size, possibly, by using (laser) beam deflection units in the form of acousto-optic deflectors, polygonal mirrors, or scanning heads, variable spot size).

[0081] Consequently, when using the lens replacement device according to the present invention, the use of F-theta lenses, telecentric lenses, etc., can generally be omitted. In addition, the (complex) necessary exchange between these lenses is eliminated (e.g., when switching from micro-material processing or marking to macro-material processing or marking).

[0082] In another embodiment of the present invention, holes are first drilled and / or cut in the glass at a distance of, for example, 50 mm to 150 mm. Some focus tracking (usually from bottom to top) is already required ((Lx) in the drawing). The change in working distance by focus tracking is in the range of 1 mm to about 50 mm. In the next step, laser material processing is interrupted for less than 5 seconds and the focus is switched to a different plane, where it is switched to a working distance range of 200 mm to 500 mm or even 1 m for using the laser material processing device to embed a photograph in plastic material, for example, or switched to marking doors, house walls, etc. from several meters and much further distances.

[0083] In addition, for small marking or microstructured areas, the use of a scanner can be omitted. By rapidly moving the lens(s) in the x and y directions, the focused laser beam is deflected after the lens. This eliminates the need for a scanner. Explanation of the symbols

[0084] List of reference symbols LMB Laser material processing device L1, L2, L3, L4, L5, L6, L1.1, L1.2, L2.1, L2.2, L3.1, L3.2, L4.1, L4.2 lens LWV, LWV1, LWV2 Lens replacement device LR laser resonator LK Laser crystal FV Non-linear optical media LS laser radiation SK Scanning head A1, A2 working distance BT component LSR Laser resonator radiation TE Carrier Element Lx Additional optical device

Claims

Claim 1 A laser material processing device (LMB) for processing a component (BT) having a complex component geometry, comprising: a laser resonator (LR); a scanning head (SK) for deflecting laser radiation; and a lens changing device (LWV), wherein the lens changing device (LWV) is arranged between the laser resonator (LR) and the scanning head (SK), and wherein the lens changing device is designed to change the working distance (A1, A2) by at least 50 mm and is suitable for such change. Claim 2 A laser material processing device (LMB) for processing a component (BT) having a complex component geometry, wherein, in claim 1, the laser material processing device (LMB) is suitable for processing the component (BT) by structurally changing the material of the component (BT). Claim 3 A laser material processing device (LMB) for processing a component (BT) having a complex component geometry, wherein, in claim 1 or 2, the laser resonator (LR) generates laser resonator radiation (LSR) having a wavelength of 0.01 nm to 400 nm, preferably 10 nm to 315 nm, particularly preferably 100 nm to 280 nm, and particularly preferably 200 nm to 280 nm. Claim 4 A laser material processing device (LMB) for processing a component (BT) having a complex component geometry, wherein, in any one of claims 1 to 3, the lens replacement device (LWV) is suitable for changing the focal length of the laser material processing device (LMB) to a range of 5 mm to 100,000 mm, preferably 20 mm to 10,000 mm, and particularly preferably 50 mm to 1,000 mm. Claim 5 A laser material processing device (LMB) for processing a component (BT) having a complex component geometry, wherein, in any one of claims 1 to 4, the lens replacement device (LWV) has one or more lenses (L1, L2, Ln). Claim 6 A laser material processing device (LMB) for processing a component (BT) having a complex component geometry, characterized in that, in claim 5, one or more lenses (L1, L2, Ln) of the lens replacement device (LWV) can be movably positioned with respect to the beam path. Claim 7 A laser material processing device (LMB) for processing a component (BT) having a complex component geometry, characterized in that, in claim 5 or 6, one or more lenses (L1, L2, Ln) of the lens replacement device (LWV) can be positioned within the beam path. Claim 8 A laser material processing device (LMB) for processing a component (BT) having a complex component geometry, characterized in that, in any one of claims 5 to 7, one or more lenses (L1, L2, Ln) are movable by rotation and / or translation. Claim 9 A laser material processing device (LMB) for processing a component (BT) having a complex component geometry, characterized in that, in any one of claims 1 to 8, the lens replacement device (LWV) and the laser resonator (LR) and / or the scanning head (SK) are arranged to be movable relative to each other. Claim 10 A laser material processing device (LMB) for processing a component (BT) having a complex component geometry, wherein, in claim 9, the lens replacement device (LWV) and the laser resonator (LR) and / or the scanning head (SK) are movable relative to each other by translational movement. Claim 11 A laser material processing device (LMB) for processing a component (BT) having a complex component geometry, wherein, in claim 10, the translational movement occurs parallel to the beam path. Claim 12 A method for modifying a working distance (A1, A2) during laser material processing comprises the following steps: • generating laser resonator radiation (LSR) from a laser resonator (LR); • coupling the laser resonator radiation (LSR) from the laser resonator (LR); • deflecting a laser radiation (LS) generated from the laser resonator radiation (LSR) onto a component (BT) to be processed using a scanning head (SK) - the first laser radiation (LS1) has a first working distance (A1) -; • modifying the first working distance (A1) of the laser radiation (LS) to a second working distance (A2) of the laser radiation (LS) - the change of the working distances (A1, A2) is achieved by replacing a first lens arranged in the beam path with a second lens using a lens replacement device (LWV) arranged between the laser resonator (LR) and the scanning head (SK), and the working distance (A1, A method for modifying a working distance (A1, A2) during laser material processing, comprising the step of deflecting the laser radiation (LS) having the second working distance (A2) onto the component to be processed, wherein the change in A2) is at least 50 mm. Claim 13 A method for modifying a working distance (A1, A2) during laser material processing, wherein, in claim 12, the laser resonator (LR) generates laser resonator radiation (LSR) having a wavelength of 100 nm to 400 nm, preferably 100 nm to 315 nm, and particularly preferably 100 nm to 280 nm. Claim 14 A method for modifying a working distance (A1, A2) during laser material processing, wherein, in order to generate the first laser radiation according to claim 12 or 13, the focal length of the laser resonator radiation (LSR) is changed by the lens replacement device (LWV). Claim 15 A method for modifying working distances (A1, A2) during laser material processing, wherein, in any one of claims 12 to 14, the lens replacement device (LWV) for changing the laser resonator radiation (LSR) having the laser resonator focal length to the first laser radiation (LS1) having the first focal length is characterized by positioning the first lens (L1) in the beam path. Claim 16 A method for modifying working distances (A1, A2) during laser material processing, wherein, in any one of claims 12 to 15, the lens replacement device (LWV) for changing the laser resonator radiation (LSR) having the laser resonator focal length and / or the first laser radiation (LS1) having the first focal length to the second laser radiation (LS2) having the second focal length is characterized by positioning a second lens (L2) in the beam path. Claim 17 A method for modifying working distances (A1, A2) during laser material processing, characterized in that, in claim 16, when positioning the second lens (L2) in the beam path, the first lens (L1) is removed from the path. Claim 18 A method for modifying working distances (A1, A2) during laser material processing, characterized in that, in claim 17, the positioning is achieved through rotational movement and / or translational movement. Claim 19 A method for modifying a working distance (A1, A2) during laser material processing, wherein, in any one of claims 12 to 18, the lens replacement device (LWV) comprises one or more lenses (L1, L2, Ln) movably arranged with respect to the beam path. Claim 20 A method for modifying a working distance (A1, A2) during laser material processing, wherein, in any one of claims 12 to 19, the lens replacement device (LWV) performs translational movement in relation to the position of the laser resonator (LR) and / or the scanning head (SK). Claim 21 A method for modifying working distances (A1, A2) during laser material processing, wherein, in paragraph 20, the translational movement occurs parallel to the beam path. Claim 22 A method for modifying a working distance (A1, A2) during laser material processing, characterized in that, in any one of claims 12 to 21, the deflection of the first laser radiation (LS1) and / or the second laser radiation (LS2) is performed by a scanning head (SK).

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