DE102021122662A1 - Optical unit for a laser processing device - Google Patents

Abstract

The invention relates to an optics unit (1) for a laser processing device (35) with at least one at least partially transmissive optics element (2) which has an optical axis (4) around which the optics element (2) can be rotated in order to change at least one property of the optics element ( 2) penetrating laser beam (3), in particular continuously, can be rotated, with a galvanometer drive (5) for rotating the optical element (2) about the optical axis (4), which has a shaft (7), with a holder (8), which connects the optics element (2) to the shaft (7) in a torque-proof manner, and with a mirror unit which comprises a mirror holder and a deflection mirror for deflecting the laser beam, the deflection mirror being on the optical axis (4) between the optics element (2) and the Shaft (7) of the galvanometer drive (5) is arranged. According to the invention, the holder extends past the mirror unit and the holder is designed in such a way that it can be moved past the mirror unit within a limited rotation angle range when the optical element (2) is rotated. The invention also relates to the laser processing device (35).

Description

The present invention relates to an optics unit for a laser processing device with at least one at least partially transmissive optics element, which has an optical axis about which the optics element can be rotated, in particular continuously, to change at least one property of a laser beam penetrating the optics element, with a galvanometer drive for rotating the Optical element around the optical axis, which has a shaft, with a holder that non-rotatably connects the optical element to the shaft, and with a mirror unit that includes a mirror holder and a deflection mirror for deflecting the laser beam, the deflection mirror on the optical axis between the Optical element and the shaft of the galvanometer drive is arranged.

Galvanometer drives have long been used as a means of rotating optical elements. It is usual here to rotate scanning mirrors, ie reflective optical elements, to deflect the beam by rotating it about an axis of rotation essentially perpendicular to the optical axis. There are, for example, from U.S. 2008/0192322 A1 or the DE 10 2004 053 298 A1 arrangements are also known in which transmissive optical elements are rotated by galvanometer scanners.

The object of the present invention is to provide an optics unit for laser processing applications with which an optics element can be adjusted with high dynamics.

The object is achieved by an optics unit and a laser processing device having the features of the independent patent claims.

An optics unit for a laser processing device is proposed. The laser processing apparatus uses a laser beam to process, for example, a workpiece such as welding, cutting, or engraving.

The optics unit comprises at least one at least partially transmissive optics element, which has an optical axis about which the optics element can be rotated in order to change at least one property of a laser beam penetrating the optics element. The laser beam is guided through the optical element. The at least one property of the laser beam is changed in that the optics element has a different orientation to the laser beam as a result of the rotation. As a result, rotating the optical element also changes the at least one property of the laser beam. The optical element can thus be rotated accordingly, depending on which characteristic of the changed property of the laser beam is required for the processing. The optical element can be rotated continuously in order to be able to continuously change the property of the laser beam. A rotational position of the optical element thus corresponds to a property of the laser beam.

In addition, the optics unit includes a galvanometer output for rotating the optics element about the optical axis, which has a shaft. With the help of the galvanometer drive, the optical element can be rotated with high dynamics.

Furthermore, the optics unit comprises a holder which connects the optics element to the shaft in a rotationally fixed manner. The holder is thus a connecting element between the galvanometer drive and the optical element.

Furthermore, the optics unit has a mirror unit, which includes a mirror holder and a deflection mirror for deflecting the laser beam, the deflection mirror being arranged on the optical axis between the optics element and the shaft of the galvanometer drive. With the help of the deflection mirror, the laser beam can be guided to the optics element if the laser beam first hits the deflection mirror and is guided from there to the optics element. Alternatively, however, the laser beam can also be guided away from the optics element, in which case the laser beam first runs through the optics element and then impinges on the deflection mirror. With the help of the deflection mirror, the laser beam can be guided to the optical axis and/or guided away from it. The deflection mirror is arranged on the optical axis between the optical element and the shaft of the galvanometer drive, so that the laser beam can be guided into the area of the optical axis or away from this area.

According to the invention, the mount extends past the mirror unit. The holder is also designed in such a way that it can be moved past the mirror unit within a limited range of angles of rotation when the optical element is rotated. As a result, the optical element and thus also the holder can be rotated without affecting the mirror unit and in particular the deflection mirror. This prevents collisions between the bracket and the mirror unit as a result of rotation of the bracket. The mount is also designed in such a way that the laser beam is not blocked or excessively vignetted when the optical element is rotated over the rotation angle range. Using the bracket Furthermore, the laser beam can be guided to the deflection mirror without being interrupted or without interruption.

It is advantageous if the mirror unit and the galvanometer drive or a drive mount of the galvanometer drive are connected directly to one another or indirectly via other structural means. Here, the galvanometer drive and the mirror unit can be firmly, in particular rigidly, connected to one another. For example, the optics unit can have a base plate on which the galvanometer drive and the mirror unit are arranged. It is also advantageous if adjustment means are provided in order to enable precise adjustment of the position of the deflection mirror during an adjustment process during assembly or when the optics unit is put into operation.

It is advantageous if the angle of rotation range is less than 360°. Furthermore, the angle of rotation range can also be less than 180°. In addition, the angle of rotation range can also be less than 45°. Furthermore, the angle of rotation range can also be less than 36°. The rotation angle range can also be 30°, 36°, 45°, 90° or 180°. In particular, the rotation angle range can be an integer fraction of 360°, which can depend on a rotational symmetry of the laser beam shape.

It is advantageous if the shaft can be rotated about an axis of rotation. Furthermore, the optical axis and the axis of rotation enclose an angle that is less than 10°. In addition, the optical axis and the axis of rotation can enclose an angle that is smaller than 1°. As a result, the optical axis and the axis of rotation of the shaft are essentially parallel to one another, so that when the optical element is rotated, this and/or the optical axis changes orientation as little as possible. The optical axis and the axis of rotation are preferably coaxial with one another, so that the orientation of the optical axis or of the optical element always remains the same during the rotation.

It is advantageous if the mount extends in a circumferential direction of the optical axis. Additionally or alternatively, the mount can at least partially surround the mirror unit in the circumferential direction. A stable connection can hereby be created when the optical element is rotated. Vibrations of the optical element that can occur when rotating are thus prevented.

It is advantageous if the holder is spaced apart from the mirror unit in a radial direction of the optical axis, in particular in the axial direction of the optical axis at least in the region of the mirror unit. As a result, the bracket can be rotated past the mirror assembly without contact between the bracket and the mirror assembly.

It is advantageous if the holder has a cavity in which the mirror unit is at least partially arranged. The mount can have at least one feed-through opening through which the mirror unit extends into the cavity. The laser beam can be fed into or out of the cavity through the same or a further feed-through opening. With the help of the cavity, the mirror unit and in particular the deflection mirror can be brought up to the optical axis and positioned close to—in particular on—the optical axis. As a result, the holder extends at least partially around the mirror unit or around the deflection mirror.

It is advantageous if the feed-through opening has an opening width of between 1 mm and 70 mm, in particular between 2 mm and 30 mm. In this way, the optics unit is designed to be compact, which in turn allows high movement dynamics due to the low masses.

It is advantageous if the laser beam is fed in or out via a feed-through opening other than a feed-through opening through which the mirror unit extends into the cavity, since the holder can thus be designed to be more compact overall and/or to have low inertia.

It is advantageous if the mount has at least two feed-through openings, with the mirror holder being introduced into the cavity through one feed-through opening and the laser beam being able to be introduced into the cavity through another feed-through opening. As a result, the through-openings can be made smaller.

It is also advantageous if the mirror unit extends through a plurality of feed-through openings at the same time, since a more rigid fastening of the deflection mirror can be achieved in this way. For example, the mirror unit can have a number of mirror holders which extend through different feed-through openings into the cavity.

Furthermore, the mirror holder can be designed as a guide tube in which the laser beam can be guided. Furthermore, the deflection mirror can be arranged on the guide tube, so that the laser beam can be guided by means of the guide tube and the deflection mirror can be introduced into the cavity.

Furthermore, the holder can be made up of at least two parts, so that the deflection mirror does not have to be passed through the feed-through opening during assembly. This can make it possible for the through-openings to be made smaller and for the holder to be made more compact and with little inertia. In addition, it can be made possible that different designs for different optical elements can be produced with a basic construction of the optical unit by providing a part of the holder in different variants for receiving different types or designs of optical elements.

It is advantageous if the holder has an inner side facing the cavity, from which the mirror unit is spaced. The inside can also be concave. As a result, the inside extends around the mirror unit.

It is advantageous if the holder has two ends that are spaced apart from one another in the circumferential direction of the optical axis. The mirror unit can extend to the optical axis between the two ends. With the aid of the ends, the holder can be spaced apart from the mirror unit, so that a collision-free movement of the holder and thus of the optical element relative to the mirror unit is made possible.

It is advantageous if the two ends are spaced apart from the mirror unit in the circumferential direction of the optical axis when the optical element is in different operating positions. As a result, the mirror unit remains at a distance from the mount without touching it, so that vibrations of the mirror unit and of the optical element, which would occur as a result of collisions between the mirror unit and the mount, are prevented.

It is advantageous if the holder extends at least in the region of the mirror unit in the circumferential direction around the axis of rotation or the optical axis over only a limited angular range. This allows a compromise to be found between stability and freedom of movement.

It is advantageous if the holder extends at least in the area around the mirror unit in the circumferential direction around the axis of rotation or the optical axis over a plurality of non-contiguous, i.e. spaced, angular areas. As a result, the weight of the mount can be reduced with high stability, which allows high movement dynamics.

It is advantageous if the holder comprises a plurality of holding arms which are spaced apart from one another in the circumferential direction of the optical axis, in particular by means of recesses. As a result, the weight of the mount can be reduced while maintaining high stability, so that movement dynamics are improved. Additionally or alternatively, the holder arms can extend in the axial direction of the optical axis from the shaft to the optical element. As a result, the holding arms connect the shaft to the optical element. For example, the holder can include three holding arms. In this case, two holding arms can be arranged opposite one another. A third holder arm can additionally or alternatively be arranged opposite the through-opening.

It is advantageous if the shaft, the mount and/or the optical element are balanced. This prevents vibrations during rotation, which lead to the laser beam being deflected and/or changed in property in an unpredictable manner. For this purpose, the shaft, the mount and/or the optics element can have at least one balancing element.

In addition or as an alternative, it is advantageous if a main axis of inertia of the mount is essentially coaxial with the shaft. This also makes it possible to prevent or at least reduce vibrations during rotation. This can be achieved by a symmetrical design of the holder. For example, the holding arms and/or the feed-through openings can be arranged with an n-fold rotational symmetry. Corresponding to a cutout that can serve as a feed-through opening, further cutouts without any other function can be provided in order to reduce the imbalance.

It is advantageous if the holder has a smaller diameter in the area of the shaft than in the area of the optical element.

A particularly low-inertia and rigid construction is made possible if the optics element rests with the edge on a substantially annular surface of the holder and is fastened by gluing or clamping.

It is advantageous if the optics unit has a sensor arrangement in order to be able to determine a rotational position of the optics element. The rotational position determined in this way can then be made available to a control unit, which can readjust the optics unit accordingly. For example, the sensor arrangement can be arranged outside of the galvanometer drive. The sensor arrangement can also determine a rotational position of the shaft of the galvanometer drive and/or the rotational position of the optical element. This sensor arrangement can be used as an alternative or in addition to an angle sensor located in the galvanometer drive the. The angle sensor can be integrated in the galvanometer drive.

It is advantageous if the optics unit has at least one bearing unit with which the optics element is mounted, in particular in an edge region. This can also be used to prevent vibrations in the optical element during rotation and to reduce the load on the bearings of the galvanometer drive.

It is advantageous if the holder is produced using a 3D printing process. As a result, the mount can be designed to have a particularly low inertia, and rapid adaptation to the optical element can also take place.

Favorable production by means of milling and/or turning is possible, for example by producing the holder starting from a rotary hollow body with a shape essentially similar to a truncated cone or cylinder by introducing recesses into the lateral surface.

It is advantageous if the holder is made from a material that has a low density and high rigidity, such as titanium, silicon or beryllium. As a result, high dynamics can be achieved when setting the optics element, ie when setting the rotational position of the optics element. The inertia can also be reduced by using a lightweight construction at least in sections, for example based on lattice structures or structures made of thin-walled elements with stiffening ribs.

It is advantageous if the optical element is a beam splitter, a beam shaper, a hologram, a grating, a delay plate, a mask diaphragm, a cylindrical lens, a polarizer, a wedge plate and/or a prism. Depending on the requirements for processing the workpiece, the appropriate optical element can be used.

It is advantageous if the optical element is a diffractive optical element for generating a beam shape, in particular a multi-beam distribution and/or a multi-focus. As a result, the processing can take place with very good quality and/or speed, in that the beam shape is quickly oriented during the laser processing process by rotating the optical element. A particularly dynamic rotation of the beam shape can be made possible with a diffractive optical element, since the mass and/or inertia of the element can be very low.

A laser processing device is also proposed. The laser processing device can be used for material processing, for example.

The laser processing device comprises at least one optics unit, which is arranged in a beam path of a laser beam, so that the laser beam can be guided through the optics unit. A property of the laser beam can be changed with the aid of the optics unit in order to adapt the laser beam to the requirements during processing.

In addition, the laser processing device comprises at least one control unit for controlling the laser processing device.

According to the invention, the optics unit is designed according to at least one feature of the preceding and/or the following description.

It is advantageous if the diameter of the laser beam in the area of the optics unit is smaller by a factor than in an area upstream of the optics unit in the beam path and/or in an area following the optics unit in the beam path, with the value of the factor being greater than or equal to 1 .5, in particular greater than or equal to 2.5. As a result, the dimensions of the optics unit can be kept small and, due to the lower mass inertia, greater dynamics of the setting can be achieved. The diameter of the laser beam is reduced for passage through the optics unit and/or then expanded.

It is advantageous if a beam reducer is arranged in the beam path in front of the optics unit, the laser beam being able to be reduced by a factor greater than 1.5, in particular greater than 2.5, by the beam reducer. This allows the diameter of the laser beam to be reduced. Additionally or alternatively, it is advantageous if a beam expander is arranged in the beam path after the optics unit, the laser beam being expandable by the beam expander by a factor greater than 1.5, in particular greater than 2.5. This allows the diameter of the laser beam to be expanded. In addition or as an alternative to the beam reducer and/or the beam expander, an intermediate focus in the area before or in or after the optical unit and/or a divergent, laser beam entering the optics unit can be used.

It is advantageous if the laser processing device includes a laser beam source for generating the laser beam. Additional or older natively, it is advantageous if the laser processing device comprises at least one deflection unit for guiding the laser beam.

It is advantageous if the laser processing device comprises a laser beam rotator, in particular a variable one, and/or means for positioning and/or for rotating the workpiece holder. In this case, particularly discrete or continuous setting values of the laser beam rotator and/or the means for rotating the workpiece holder can have a larger angular range than the particularly continuous angular range of rotation of the optics unit. In addition or as an alternative, it is advantageous if the setting dynamics of the laser beam rotator and/or the means for rotating the workpiece holder are lower than the setting dynamics of the optics unit. As a result, the required high movement dynamics and/or adjustment dynamics are concentrated on one component, namely the optics unit.

It is advantageous if the laser processing device includes a scan head for guiding the laser beam onto a workpiece to be processed. With the help of the scan head, the laser beam can be directed onto the workpiece.

It is advantageous if the laser machining device comprises a workpiece holder for a workpiece to be machined, which is designed to move the workpiece, in particular in a translatory and/or rotary manner.

It is advantageous if the control unit is designed in such a way that it controls the optics unit together with other elements for manipulating the laser beam, for positioning and/or aligning the laser beam relative to the workpiece and/or the means for positioning and/or aligning the workpiece synchronized control. The additional elements for manipulating the laser beam can be, for example, the laser beam source, zoom optics, the deflection unit, a focusing unit and/or another laser beam rotator. The means for positioning and/or aligning the workpiece can be, for example, the workpiece holder and/or the means for positioning and/or rotating the workpiece holder. The processing quality by means of the laser beam can be improved with the help of the synchronization of the elements of the laser processing device. The control unit can thus control the laser processing device in a synchronized manner.

When setting up the optics unit, at least two adjustable deflection mirrors (or also called deflection mirrors) can preferably be used in the beam path before and/or after the optics unit in order to be able to precisely adjust the laser beam to the optical axis in all four degrees of freedom of the beam position. Optionally attachable screens or crosshairs at the entrance and exit of the optics unit or a sensor for measuring the beam position can be provided as an adjustment aid.

Some possible particularly advantageous applications of the optics unit in a laser processing device are described below by way of example but not exhaustively.

An optical beam shaper or beam splitter can be used as the optical element in order to generate a beam shape, in particular one that is not rotationally symmetrical, or a multi-beam. A laser machining process can be optimized in this way, for example by a targeted distribution of the energy to the process zone. By means of the optics unit, the orientation of the beam shape can be adapted to the current feed direction of the movement of the laser beam relative to the workpiece during the process control. For this purpose, the control unit calculates the current feed direction, for example from the actual or target path of a scanning system and/or the actual or target path of a workpiece movement, and controls the optics unit with the corresponding target alignment. The orientation of the jet shape can thus be set, for example, tangentially to the path of the feed or at another angle defined by a calculation rule stored in the controller.

The information about the actual and/or desired trajectory courses can be determined in the controller, for example, by existing control values of other synchronously controlled actuators or by measured sensor data.

If a shaped beam is deflected by a galvanometer scanning system, large deflection angles usually result in an undesirable distortion of the beam shape, which can be described to a good approximation by rotating the beam shape. Based on a numerical model of the distortion or a table with correction values depending on the deflection angle of the two axes of the galvanometer scanning system, the control unit can control the optics unit with a target value that has been changed by a correction value and that causes at least a partial correction of the distortion.

Optical arrangements consisting of two diffractive optical elements following one another in the beam path are known, in which a relative rotation of the two elements to one another causes a change in the beam shape, as a result of which the beam shape varies continuously, for example the can. If at least one of the two elements is integrated as an optical element in an optical unit according to the invention, a particularly dynamic variation of the beam shape is made possible. Even greater dynamics and a larger adjustment range can be achieved if the second element in a second arrangement according to the invention is rotated simultaneously and synchronously in the opposite direction.

A known principle for the variable attenuation of a polarized laser beam is the rotation of the polarization by means of a lambda/2 retardation plate and the decoupling of part of the laser beam with a polarizing beam splitter following in the beam path. If the retardation plate is adjusted with an optical unit according to the invention, particularly high dynamics can be achieved when adjusting the attenuation.

The rotation of polarization optics such as delay plates or polarizers can also be advantageous in order to optimize the laser process during laser processing of a workpiece through a targeted variation of the polarization.

A cylindrical lens or a group of cylindrical lenses can be used in a laser processing device in order to compensate for or generate astigmatism and/or to achieve a rotationally symmetrical or specifically non-rotationally symmetrical intensity distribution in a processing point on the workpiece. If a cylindrical lens is used in an optical unit according to the invention, the alignment of the astigmatic effect can be adjusted very quickly. In connection with a synchronously controlled galvanometer scanning system, such an arrangement can be used, for example, as compensation in order to ensure the homogeneity of the intensity distribution on the workpiece over a larger area of the scan field. The surface shape of a non-planar workpiece and/or the angle of incidence of the laser beam on the workpiece surface can also be included in the calculation of the compensation.

The shape of an intensity distribution in a processing focus on the workpiece can be changed by vignetting a laser beam with an aperture or mask. If a non-rotationally symmetrical diaphragm or mask is used and rotated with an optical unit according to the invention, the adjustment can be made particularly dynamically. In connection with a scanning system, for example, a targeted compensation of an inhomogeneity of the focus geometry over the scanning field can be achieved.

A Dove prism is a transmissive optical element in which the laser beam undergoes a spatial rotation around the optical axis as a result of several internal reflections. The generated optical rotation angle corresponds to twice the mechanical angle of the angular position of the Dove prism. By means of three mirrors in a corresponding spatial arrangement ("K-mirror"), an overall transmissive optical element can also be produced from these actually reflective sub-components, which corresponds in effect to the Dove prism. Such beam rotators can be used as an optical element in an optical unit according to the invention in order to rotate the beam shape of an already formed beam in a targeted and adjustable manner. The effect of such beam rotators adds up in a cascaded arrangement.

Alternatively, a jet rotator can also be rotated by means of another, in particular slower, actuator with a larger adjustment range, such as a hollow shaft motor. In connection with an optical unit according to the invention, an even larger angular range can thus be made accessible for use. For this purpose, the beam rotator is arranged in the beam path after the optics unit. The controller divides a target movement into these redundant rotational degrees of freedom in such a way that the high-frequency components are transmitted to the optics unit according to the invention and the low-frequency components are transmitted to the variable beam rotator following in the beam path.

Another strategy for dealing with the limited range of rotation angles of the optics unit in applications is to provide optical means for switchable, discrete rotation of the beam profile in the beam path. For example, a galvanometer scanner can be used as a beam switch in order to switch between different optical channels in which, for example, a fixed beam rotation is effected by a suitable mirror arrangement.

A further advantageous strategy is to rotate a beam shaper as an optical element with the optics unit, which produces a beam shape with an n-fold rotational symmetry. Because of the symmetry, the limited range of rotation angles of the optics unit can be sufficient to set a large proportion of the possible orientations.

When choosing the processing strategy in connection with a galvanometer scanning system, the limited angle range can be suitably taken into account. For example, the hatching direction can be adjusted to the accessible angular range when filling an area. through the orientable beam shape, the area rate can be increased when generating the hatching. In the same way, the process throughput can be increased when processing a curved, linear structure, such as, for example, the production of a groove or a trench by means of a laser ablation process.

A diffractive optical element can also be used to generate a multifocus distribution in which the foci are spaced apart both laterally to the optical axis and in the direction of the optical axis, ie are arranged, for example, in a plane that is tilted obliquely to the laser beam. This can be used for laser processing of a workpiece when the laser is not perpendicular or when laser processing curved surfaces to ensure that several foci are imaged sharply on the workpiece at the same time. An optical unit according to the invention can be used in connection with the actuators, which bring about a relative movement of the laser to the workpiece, in order to rotate the multifocus in a suitable manner in order to follow the contour of the machining. For example, when externally machining a rounded edge of a workpiece, a curve of the edge can be followed. This can, for example, speed up the machining process when processing the edges of glass or laser processing the cut edges of processing tools such as milling cutters, indexable inserts or drills.

A segmented element can be used as the optics element, in which each sector of the optics element brings about a different expression of a beam property, for example a beam shape. With the optics unit according to the invention, the laser beam can be guided much closer to the axis of rotation, as a result of which greater dynamics are achieved when changing the irradiated segment by rotating the optics element. In addition, the segmented optics element can be manufactured much more cost-effectively with a smaller diameter.

• 1 eine perspektivische Ansicht der Optikeinheit mit Laserstrahl,
• 2 eine seitliche Schnittansicht der Optikeinheit mit Laserstrahl,
• 3 eine weitere perspektivische Ansicht der Optikeinheit mit Laserstrahl,
• 4 eine weitere Ausführung der Optikeinheit mit einem Halteelement, in dem das Optikelement eingesetzt ist,
• 5a eine schematische Draufsicht auf die Halterung und die Spiegeleinheit,
• 5b eine weitere schematische Draufsicht auf die Halterung und die Spiegeleinheit und
• 6 einen schematischen Aufbau der Laserbearbeitungsvorrichtung.

Further advantages of the invention are described in the following exemplary embodiments. Show it:

• 1 a perspective view of the optics unit with laser beam,
• 2 a side sectional view of the optics unit with laser beam,
• 3 another perspective view of the optics unit with laser beam,
• 4 a further embodiment of the optics unit with a holding element in which the optics element is inserted,
• 5a a schematic plan view of the bracket and the mirror unit,
• 5b a further schematic plan view of the holder and the mirror unit and
• 6 a schematic structure of the laser processing device.

1 shows a perspective view of an optical unit 1 for a laser processing device 35. With the help of the laser processing device 35, for example, workpieces can be processed, such as welded, engraved or cut. 2 also shows the optics unit 1 in a side sectional view. The two 1 and 2 are considered and explained together. For the sake of simplicity and clarity, features can only be in one of the two 1 and 2 be provided with a reference number.

The optics unit 1 comprises at least one at least partially transmissive optics element 2, which has an optical axis 4 about which the optics element 2 can be rotated in order to change at least one property of a laser beam 3 penetrating the optics element 2, in particular continuously.

Depending on the orientation of the optical element 2 to the laser beam 3, this is changed. If the optics element 2 is rotated relative to the laser beam 3, at least one property of the laser beam 3 also changes. In this way, the property of the laser beam 3 that is currently required for processing the workpiece can be set. This is done in a simple manner by rotating the optical element 2 about its optical axis 4 . For example, the laser beam 3 can be split by means of the optics element 2, wherein a rotational position of the optics element 2 can specify how the partial beams of the split beam are oriented.

In principle, the laser beam 3 can be guided through the optical element 2 in both directions. The optics unit 1 must then be arranged accordingly. According to the present exemplary embodiment, the laser beam 3 leads from the galvanometer drive 5 described below through the optical element 2. According to FIGS 1 and 2 the laser beam 3 thus passes through the optics element 2 from bottom to top. As already described, the laser beam 3 can also be passed through the optics element 2 from top to bottom.

The laser beam 3 is formed by an entering laser beam 9 and an exiting laser beam 10 . The emerging laser beam 10 is here with represented by a thick line. This also means that at least one property of the laser beam 3 has changed.

The laser beam 3 also has a kink here, which is caused by a deflection mirror 15, not shown here. The deflection mirror 15 or the mirror unit 13 is in 2 shown.

Furthermore, the optics unit 1 includes a galvanometer drive 5 for rotating the optics element 2 around the optical axis 4 . The galvanometer drive 5 has a shaft 7 which can be rotated around an axis of rotation 6 .

The optics unit 1 also has an axial direction 11 which is oriented parallel to the optical axis 4 here. Likewise, the optics unit 1 has a circumferential direction 12 . The optical element 2 can be rotated in the direction of the circumferential direction 12 .

Furthermore, the optics unit 1 has a mount 8 which connects the optics element 2 to the shaft 7 in a rotationally fixed manner. The mount 8 is thus a connecting element for connecting the optical element 2 to the galvanometer drive 5 or the shaft 7. The mount 8 thus transmits the rotation of the galvanometer drive 5 to the optical element 2.

The optics unit 1 also includes a mirror unit 13 which includes a mirror holder 14 and a deflection mirror 15 for deflecting the laser beam 3 . The mirror unit 13 is in 2 and shown in at least one other figure.

In this case, the holder 8 extends past the mirror unit 13 and the holder 8 is designed in such a way that it can be moved past the mirror unit 13 within a limited rotation angle range when the optical element 2 is rotated. In particular, the mount 8 can extend past the mirror unit 13 without touching it when the optical element 2 and thus also the mount 8 are rotated. When rotating the optical element 2, the holder 8 can also move past the mirror unit 13 and in particular the deflection mirror 15, in particular without contact. This can prevent a collision between the mirror unit 13 or the deflection mirror 15 and the holder 8, which would lead to a movement or vibration of the deflection mirror 15. However, such a movement of the deflection mirror 15 due to such collisions is disadvantageous for the guidance of the laser beam 3.

Furthermore, it is advantageous if the holder 8 is spaced apart from the mirror unit 13 or from the deflection mirror 15 . In addition or as an alternative, it is advantageous if the holder 8 is spaced apart from the optical axis 4 laterally and/or in a radial direction. The radial direction refers to the optical axis 4.

The mount 8 also has a first end 36 and a second end 37 which are spaced from the mirror unit 13 and remain spaced from the mirror unit 13 even when the optical element 2 and the mount 8 are rotated.

The mirror unit 13 or the deflection mirror 15 is arranged in such a way that the laser beam 3 can be guided to the optical axis 4 . As shown in the present embodiment, the optical axis 4 extends through the deflection mirror 15.

Furthermore, the holder 8 comprises at least one holding arm 16 which connects the optics element 2 to the shaft 7 . In the present exemplary embodiment, the holder 8 comprises three holding arms 16a - 16c, which 1 are good to see.

The holder 8 also has a cavity 17 in which the mirror unit 13 or the deflection mirror 15 is at least partially arranged. According to the present exemplary embodiment, the hollow space 17 is arranged between the optical element 2 and the galvanometer drive 5 and/or the shaft 7 .

Furthermore, the holder 8 has at least one feed-through opening 18 through which the mirror unit 13, in particular the deflection mirror 15 and/or the mirror holder 14, and/or the laser beam 3 can be guided into the cavity 17. According to the 1 and 2 the mirror unit 13, in particular the deflection mirror 15 and/or the mirror holder 14, and the laser beam 3 are passed through the same feed-through opening 18. In addition, as will be described below, the holder 8 can have a plurality of through-openings 18a-18c. Thus, the first through-opening 18a is arranged between the first holding arm 16a and the third holding arm 16c. The second through opening 18b is arranged between the first holding arm 16a and the second holding arm 16b. The third through opening 18c is arranged between the second holding arm 16b and the third holding arm 16c.

With the aid of the plurality of feed-through openings 18a-18c, the mirror unit 13 and the laser beam 3 can be guided through feed-through openings 18a-18c that are different from one another. The optics unit 1 of the present exemplary embodiment has, for example, three feed-through openings 18a-18c. As in 1 and 2 1, the mirror unit 13 and the laser beam 3 are passed through the first through hole 18a. Exemplary the mirror unit 13 can also be guided through the first through-opening 18a and the laser beam 3 through the third through-opening 18c.

The first through opening 18a is arranged between the first and the second end 36, 37 here.

According to the present exemplary embodiment, the first holding arm 16a and the third holding arm 16c are arranged opposite one another, in particular with respect to the optical axis 4 and/or the shaft 7 . Furthermore, the second holding arm 16b and the first through-opening 18a are arranged opposite one another.

Furthermore, the holder 8 has an inner side 38 which, according to the present exemplary embodiment, is in particular of concave design. It is advantageous if the mirror unit 13, in particular the deflection mirror 15 and/or the mirror holder 14, is at a distance from the inside 38.

Features that have already been described in at least one of the previous figures cannot be explained again for the sake of simplicity. Furthermore, features can also only be described in this figure or in at least one of the following figures. Furthermore, for the sake of simplicity, the same reference numbers are used for the same features. In addition, for the sake of clarity, not all features can be shown in the following figures and/or provided with a reference number. However, features shown in one or more of the preceding figures may also be present in this one or in one or more of the following figures. Furthermore, for the sake of clarity, features can also only be shown in this figure or in one or more of the following figures and/or provided with a reference number. Nevertheless, features that are only shown in one or more of the following figures can also already be present in this or a previous figure.

3 shows a further exemplary embodiment of the optics unit 1. According to the present exemplary embodiment, the galvanometer drive 5 is arranged or fastened by means of a drive holder 19 on a base plate 20, in particular in a rotationally fixed manner. The mirror unit 13 , in particular the mirror holder 14 , is also arranged on the base plate 20 . The mirror unit 13 is advantageously also arranged or fastened in a rotationally fixed manner on the base plate 20 . As a result, the galvanometer drive 5 and the mirror unit 13 are fixed or non-rotatable to one another. Furthermore, the shaft 7 of the galvanometer drive 5 can rotate relative to the base plate 20 or relative to the mirror unit 13 . As a result, the holder 8 and the optical element 2 can also move freely relative to the deflection mirror 15 or relative to the mirror unit 13 . Furthermore, the optics element 2 and the holder 8 can also rotate in relation to the base plate 20 . The base plate 20 is also a connecting unit between the mirror unit 13 and the galvanometer drive 5 and the mount 8 arranged thereon with the optical element 2.

According to the present embodiment, the holder 8 also has three through-openings 18a-18c. Furthermore, according to the present exemplary embodiment, the laser beam 3 is guided into and out of the cavity 17 through the first feed-through opening 18a. The laser beam 3 passes through the first feed-through opening 18a. The mirror unit 13, on the other hand, is guided into the cavity 17 through the third feed-through opening 18c. The laser beam 3 and the mirror unit 13 are thus guided into the cavity 17 through different feed-through openings 18a-18c.

Furthermore, the optics unit 1 of the present exemplary embodiment has an angle sensor 21, by means of which a rotational position of the galvanometer drive 5 and thus of the optics element 2 can be determined.

4 shows an embodiment of the optics unit 1 in which the optics element 2 is inserted into a holding element 22 . The mount 8 also includes the holding element 22 into which the optical element 2 is inserted. According to the present exemplary embodiment, the optical element 2 can be connected to the holding element 22 by means of a connecting element 23 . The connecting element 23 can also be a fixing element. The holding element 22 has a passage opening 24 into which the optics element 2 is inserted.

According to 3 and 4 the holding arms 16a - 16c and/or the feed-through openings 18a - 18c have a rotational symmetry. According to the present exemplary embodiments, the holding arms 16a-16c and/or the feed-through openings 18a-18c have a symmetry when rotated by 120°.

5a shows a schematic plan view of the holder 8 and the mirror unit 13. The holder 8 comprises three holder arms 16a-16c, which are arranged symmetrically. Here the holder arms 16a - 16c are arranged in 120° symmetry. A feed-through opening 18a-18c is arranged between each two adjacent holder arms 16a-16c. These also have 120° symmetry. This means in particular that the holder arms 16a - 16c and the through-opening gen 18a - 18c each have the same dimensions. In particular, the at least one through-opening has an opening width 39a-39c, with the opening widths 39a-39c of the through-openings 18a-18c being the same as one another in this exemplary embodiment. Furthermore, the opening widths 39a - 39c are in the range of 60°. According to the opening width 39, the optical element 2 and thus the holder 8 can be rotated without the holder 8 hitting the mirror unit 13, which leads to shaking and consequently to vibrations of the deflection mirror 15. This is to be avoided since the machining process by the laser 3 is unpredictably disrupted as a result.

Furthermore, the mount 8 and thus the optical element 2 can be rotated to such an extent that the laser beam 3 is not interrupted or blocked by the mount 8 or the holding arms 16a-16c. The arrangement and design of the mount 8 and/or the holding arms 16a-16c thus specifies the angle of rotation range through which the optical element 2 can be rotated.

Furthermore, the mirror unit 13 has two mirror holders 14a, 14b. According to the present exemplary embodiment, the first mirror holder 14a extends through the third through-opening 18c and the second mirror holder 14b extends through the second through-opening 18b. As a result, the deflection mirror 15 can be held more stably. According to the present exemplary embodiment, the laser beam 3 extends through the first feed-through opening 18a.

5b shows a further schematic top view of the holder 8 and the mirror unit 13. Here, a large number of holding arms 16a-161 (twelve in all) are shown. Furthermore, two feed-through openings 18a, 18b are shown, through which the mirror unit 13 and/or the laser beam 3 can be fed. According to the present exemplary embodiment, both the mirror unit 13 and the laser beam 3 extend through the first feed-through opening 18a.

The two opening widths 39a, 39b shown here are compared to 5a greater. The opening widths 39a, 39b here are in the range around or greater than 90°. Accordingly, the optical element 2 can be rotated through a rotation angle range of 90° without the holder 8 hitting the mirror unit 13 or without the laser beam 3 being blocked by the holder 8 .

A gap 25 is arranged between the holding arms 16a-16f shown here and between the holding arms 16g-161. For the sake of clarity, only one gap 25 is provided with a reference number here. The gap 25 can only be used to a very limited extent to guide the laser beam 3 into the cavity 17 . Although it is possible, according to the present embodiment of the holding arms 16a-161, the range of the angle of rotation is very severely limited. Rather, the gap 25 can serve to avoid additional weight of the mount 8 or to keep the weight of the mount 8 low, so that higher movement dynamics of the optical element 2 can be achieved.

A further embodiment of the holder 8 is similar to the embodiment according to FIG 5b . For example, the holding arms 16a-16f and/or the holding arms 16g-16l can be connected to one another so that there is a single holding arm 16 on which stiffening ribs are arranged, which then have a cross-section similar to the plurality of holding arms 16a-16l.

6 shows a schematic structure of the laser processing device 35. According to the present exemplary embodiment, the laser processing device 35 comprises a laser source 26 for generating the laser beam 3. The laser beam 3 with its guidance is represented here by the thick arrows.

Furthermore, the laser processing device 35 can have a first deflection mirror 27 in order to guide the laser beam 3 to the optics unit 1 . The optics unit 1 comprises the deflection mirror 15 already described and the optics element 2 in order to change at least one property of the laser beam 3 . The changed laser beam 3 thus leads away from the optics unit 1 .

Downstream of the optics unit 1 , the laser processing device 35 of the present exemplary embodiment has a second deflection mirror 28 which deflects the laser beam 3 .

The laser processing device 35 then includes a zoom lens 29.

The laser beam 3 is then guided to a scan head 30 . According to the present exemplary embodiment, the laser processing device 35 and/or the scan head 30 comprise a focusing unit 31, by means of which the laser beam 3 can be focused in order to focus the laser beam 3 on the workpiece 32 or towards the workpiece holder in which the workpiece 32 is held to lead.

Furthermore, the laser processing device 35 comprises a control unit 33 for controlling the laser processing device 35. In the one shown here 6 control commands 34 are shown by dashed arrows. This is to indicate that the control unit 33, the laser source 26, the optics unit 1, the zoom optics 29, the scan head 30 and/or the workpiece 32 or a workpiece holder for the workpiece 32 can control. In particular, the control unit 33 is designed to control the laser processing device 35 or at least the 6 synchronously control the elements shown so that the laser beam 3 is guided onto the workpiece 32 as planned.

The present invention is not limited to the illustrated and described embodiments. Modifications within the scope of the patent claims are just as possible as a combination of the features, even if they are shown and described in different exemplary embodiments.

Reference List

1

optical unit

2

optical element

3

laser beam

4

optical axis

5

galvanometer drive

6

axis of rotation

7

Wave

8th

bracket

9

incoming laser beam

10

exiting laser beam

11

axial direction

12

circumferential direction

13

mirror unit

14

mirror holder

15

deflection mirror

16

holding arm

17

cavity

18

through hole

19

drive bracket

20

base plate

21

angle sensor

22

holding element

23

fastener

24

passage opening

25

gap

26

laser source

27

first deflection mirror

28

second deflection mirror

29

zoom optics

30

scan head

31

focusing unit

32

workpiece

33

control unit

34

control commands

35

laser processing device

36

first end

37

second end

38

inside

39

opening width

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US20080192322A1 [0002]
• DE 102004053298 A1 [0002]

Claims (19)

Optical unit (1) for a laser processing device (35) with at least one at least partially transmissive optical element (2), which has an optical axis (4) around which the optical element (2) is used to change at least one property of a laser beam penetrating the optical element (2). (3), in particular continuously, with a galvanometer drive (5) for rotating the optical element (2) about the optical axis (4), which has a shaft (7), with a holder (8) which supports the optical element ( 2) non-rotatably connected to the shaft (7), and with a mirror unit, which comprises a mirror holder and a deflection mirror for deflecting the laser beam, the deflection mirror on the optical axis (4) between the optical element (2) and the shaft (7) of the galvanometer drive (5), characterized in that the holder extends past the mirror unit and in that the holder is designed in such a way that when the optical element (2) is rotated, it attaches to de r mirror unit can be moved past within a limited range of rotation angles. Optical unit according to the preceding claim, characterized in that the galvanometer drive (5) and the mirror unit (13) are connected to one another directly or indirectly, the optics unit (1) preferably having a base plate (20) on which the galvanometer drive (5) and the mirror unit (13) are arranged. Optical unit according to one or more of the preceding claims, characterized in that the angle of rotation range is less than 360°, in particular less than 180°, preferably less than 45°. Optical unit according to one or more of the preceding claims, characterized in that the shaft (7) can be rotated about an axis of rotation (6) and that the optical axis (4) and the axis of rotation (6) enclose an angle which is less than 10° , in particular is less than 1 °, wherein the optical axis (4) and the axis of rotation (6) are preferably coaxial to each other. Optical unit according to one or more of the preceding claims, characterized in that the holder (8) extends in a circumferential direction (12) of the optical axis (4) and/or the holder (8) the mirror unit (13) in the circumferential direction (12 ) at least partially surrounds. Optical unit according to one or more of the preceding claims, characterized in that the holder (8) is spaced apart from the mirror unit (13) in a radial direction of the optical axis (4), in particular in the axial direction (11) of the optical axis (4) at least in Area of the mirror assembly (13). Optical unit according to one or more of the preceding claims, characterized in that the holder (8) has a cavity (17) in which the mirror unit (13) is at least partially arranged, and wherein the holder (8) preferably has at least one, in particular at least two lead-through openings (18) through which the mirror unit (13) extends into the cavity (17) and/or through which the laser beam (3) can be introduced or removed from the cavity (17). Optical unit according to one or more of the preceding claims, characterized in that the feed-through opening (18) has an opening width (39) of between 1 mm and 70 mm, in particular between 2 mm and 30 mm. Optical unit according to one or more of the preceding claims, characterized in that the mount (8) has two ends (36, 37) spaced apart from one another in the circumferential direction (12) of the optical axis (4). Optical unit according to one or more of the preceding claims, characterized in that the two ends (36, 37) are spaced apart from the mirror unit (13) in different operating positions of the optical element (2) in the circumferential direction (12) of the optical axis (4). Optical unit according to one or more of the preceding claims, characterized in that the holder (8) comprises a plurality of holding arms (16) which are spaced apart from one another in the circumferential direction (12) of the optical axis (4), in particular by means of recesses, and/or are in Extend axial direction of the optical axis (4) from the shaft (7) to the optical element (2). Optical unit according to one or more of the preceding claims, characterized in that the shaft (7), the mount (8) and/or the optical element (2) are balanced and/or have at least one balancing element and/or that a main axis of inertia of the mount ( 8) is substantially coaxial with the shaft (7). Optical unit according to one or more of the preceding claims, characterized in that the optical element (2) is a beam splitter, a beam shaper, a hologram, a grating, a delay plate, a mask diaphragm, a cylinder lens, a polarizer, a wedge plate and/or a prism. Optical unit according to one or more of the preceding claims, characterized in that the optical element (2) is a diffractive optical element for generating a beam shape, in particular a multi-beam distribution and/or a multi-focus. Laser processing device (35), in particular for material processing, with at least one optics unit (1), which is arranged in a beam path of a laser beam (3), so that the laser beam (3) can be guided through the optics unit (1), and with at least one Control unit (33) for controlling the laser processing device (35), characterized in that the optics unit (1) is designed according to one or more of the preceding claims. Laser processing device according to one or more of the preceding claims, characterized in that the diameter of the laser beam (3) in the area of the optics unit (1) is smaller by a factor than in an area upstream of the optics unit (1) in the beam path and/or in a the area following the optics unit (1) in the beam path, the value of the factor being greater than or equal to 1.5, in particular greater than or equal to 2.5. Laser processing device according to one or more of the preceding claims, characterized in that a beam reducer is arranged in the beam path in front of the optics unit (1), the laser beam (3) being able to be reduced by a factor greater than 1.5, in particular greater than 2.5, by the beam reducer and/or that a beam expander is arranged in the beam path after the optics unit (1), the laser beam (3) being expandable by the beam expander by a factor greater than 1.5, in particular greater than 2.5. Laser processing device according to one or more of the preceding claims, characterized in that the laser processing device (35) comprises a, in particular variable, laser beam rotator and/or means for positioning and/or rotating the workpiece holder, with, in particular discrete or continuous, setting values of the laser beam rotator and/or or the means for rotating the workpiece holder have a larger angular range than the, in particular continuous, angle of rotation range of the optics unit (1) and/or wherein the adjustment dynamics of the laser beam rotator and/or the means for rotating the workpiece holder are lower than the adjustment dynamics of the optics unit. Laser processing device according to one or more of the preceding claims, characterized in that the control unit (33) is designed in such a way that it controls the optics unit (1) together with other elements for manipulating the laser beam (3), for positioning and/or for aligning the laser beam (3) relative to the workpiece (32) and/or the means for positioning and/or aligning the workpiece (32) in a synchronized manner.

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