DE102021131456A1 - line optics system - Google Patents

Abstract

The present invention relates to a line optics system (10) for generating a defined laser line (28) on a working plane (29), having: at least one laser light source (12) for generating at least one laser beam (20); a first optical arrangement (14), which is set up to generate at least two input beam groups (22, 22', 22'', 22''') from the at least one laser beam (20), each input beam group (22, 22' , 22'', 22''') has at least two partial beams (30', 30'', 30''); a beam mixing unit (16) which is set up to mix the at least two input beam groups (22, 22', 22'', 22''') with one another in order to produce at least two mixed output beam groups (24, 24', 24'', 24 ''') to create; and a second optical arrangement (18) which is set up to generate a combined illumination beam (26) from the at least two mixed output beam groups (24, 24', 24'', 24''') along a beam path, the combined The illumination beam (26) defines a beam direction which intersects the working plane (29), the combined illumination beam (28) forming the defined laser line (28) in the area of the working plane.

Description

The present invention relates to a line optics system for generating a defined laser line on a working plane.

Such a line optics system is basically over U.S. 2006/182 155 A1 known.

The line-shaped laser illumination of such a line optics system can advantageously be used to thermally process a workpiece. The workpiece can be, for example, a plastic material on a glass plate, which serves as a carrier material. The plastic material can in particular be a film on which organic light-emitting diodes, so-called OLEDs, and/or thin-film transistors are produced. OLED films are increasingly being used for displays in smartphones, tablets, televisions and other screen display devices. After the electronic structures have been produced, the film must be detached from the glass carrier. This can be done with laser illumination in the form of a thin laser line, which is moved at a defined speed relative to the glass plate and in doing so detaches the adhesive bond of the film through the glass plate. In practice, such an application is often referred to as LLO or Laser Lift Off.

Another frequently used application for the sequential illumination of a workpiece with a defined laser line can be the line-by-line melting of amorphous silicon on a carrier plate. Here, too, the laser line is moved at a defined speed relative to the workpiece surface. The comparatively inexpensive amorphous silicon can be converted into higher-quality polycrystalline silicon by melting it and then cooling it down. In practice, such an application is often referred to as Solid State Laser Annealing SLA, Sequential Lateral Solidification (SLS) or Excimer Laser Annealing (ELA).

Such applications require a laser line on the working plane that is as long as possible in one direction in order to cover the widest possible working area and that is very short in comparison in the other direction in order to provide the energy density required for the respective process . Accordingly, a long, thin laser line with a very large aspect ratio of line length to line width is desirable. For typical applications, a line length of 100mm and more with a linewidth of the order of 20µm may be desirable. The direction in which the laser line runs is usually referred to as the long axis (LA) and the line width as the short axis (SA) of the so-called beam profile. As a rule, the laser line should have a defined intensity curve in both axes. It is often desirable for the laser line to have an intensity profile that is as rectangular or trapezoidal as possible in the long axis, with the latter being advantageous if several laser lines are to be joined together to form a longer overall line. Depending on the application, a rectangular intensity profile (so-called top hat profile) or a Gaussian profile is often desired in the short axis.

WO 2018/019374 A1 discloses a device for generating such a laser line with numerous details concerning the elements of the optical arrangement. The optical arrangement here includes a collimator that collimates a raw laser beam, as well as a beam transformer, a homogenizer and a focusing stage. The beam transformer takes the collimated raw beam and expands it in the long axis. In principle, the beam transformer can also accept several raw laser beams from several laser sources and combine them into an expanded laser beam with higher power. The homogenizer produces the desired beam profile in the long axis. The focusing stage focuses the reshaped laser beam on a defined position in the area of the working plane. The known device is suitable for LLO and SLA applications and can be implemented with laser radiation with wavelengths from the infrared (IR) to the ultraviolet (UV) range.

The intensity distribution of line optics systems consists of a homogeneous intensity distribution in the long axis of the beam profile and a narrow profile along the short axis. The homogeneity of the long axis is usually disturbed by local inhomogeneities, which originate from the beam shaping principle or are caused by the surface properties of the optics. Sensitivity to such interference decreases because the beam source used loses spatial coherence.

U.S. 2006/182155 A1 discloses that in a photomask projection system, a photomask mask is illuminated by light from two lasers. A beam from one of the lasers is mixed with a beam from the other laser to provide two mixed beams, each containing a portion of the beams from both lasers. The mixed beams are directed at an angle to one another and intersect on the photomask.

Against this background, it is an object of the present invention to provide a line optical system that has as homogeneous a Intensity profile of the laser line allows. In particular, it is an object of the present invention to reduce spatial coherence and spurious irregularities.

According to one aspect, this object is achieved by a line optics system for generating a defined laser line on a working plane. The line optics system has at least one laser light source for generating at least one laser beam, a first optical arrangement, a beam mixing unit, and a second optical arrangement. The first optical arrangement is set up to generate at least two input beam groups from the at least one laser beam, each input beam group having at least two partial beams. The beam mixing unit is set up to mix the at least two input beam groups with one another in order to generate at least two mixed output beam groups. The second optical arrangement is set up to generate a combined illumination beam from the at least two mixed output beam groups along a beam path, with the combined illumination beam defining a beam direction that intersects the working plane, with the combined illumination beam forming the defined laser line in the area of the working plane.

The at least one laser light source can be a UV laser light source for generating a UV laser beam or an IR laser light source for generating an IR laser beam. The at least one laser light source can be set up to generate more than one laser beam. In particular, a plurality of laser light sources can be provided, each laser light source being set up to generate a respective laser beam.

The first optical arrangement generates the input beam groups by bundling the partial beams to form the corresponding input beam groups. The number of partial beams in each input beam group is preferably the same. Preferably, the input beam groups are mutually incoherent.

The partial beams can be generated by beam splitting of the at least one laser beam, the at least one laser light source. In particular, a laser light source can be provided for each input beam group, each of which generates a laser beam. Each laser beam can then be divided into sub-beams, which are then bundled to form the respective input beam group. Alternatively, the number of partial beams can correspond to the number of laser light sources, with each laser beam of a laser light source forming a partial beam.

In each input beam group, the partial beams preferably run parallel to one another. Alternatively, each input beam group can also have converging or diverging partial beams. The sub-beams of each input beam group do not overlap. This means that in an input beam group, adjacent sub-beams are spaced apart. The adjacent partial beams are at a defined distance from one another. The defined distance is preferably the same in all input beam groups. In particular, adjacent sub-beams in each input beam group have an offset in a lateral direction. The offset can be the same in all input beam groups. Each beam group has a beam direction. The beam direction defines the propagation direction of the beam group. In this context, the term "lateral" is to be understood as perpendicular to the beam direction of the respective beam group.

The beam mixing unit is set up to mix the at least two input beam groups with one another in order to generate at least two mixed output beam groups. Like the input beam groups, each output beam group has partial beams. In each output beam group, the partial beams preferably run parallel to one another. Alternatively, each output beam group can also have converging or diverging partial beams. Preferably, the number of input beam groups corresponds to the number of output beam groups. The number of sub-beams in each output beam group is at least four. In particular, the number of partial beams of each output beam group is equal to or greater than the number of all partial beams of the input beam groups. For example, an output beam group has at least four sub-beams if the number of input beam groups is two and the number of sub-beams per input beam group is also two. Preferably, the number of sub-beams in each input beam group is three. With two input beam groups, each output beam group then has at least six partial beams.

Each output beamgroup is created by merging the input beamgroups. For mixing, the sub-beams of each input beam group are divided into sub-groups. The sub-beams can be split once or multiple times so that two or more sub-groups are formed. The subgroups from the input beam groups are combined to form the output beam groups. In particular, subgroups from each input beam group are combined to form an output beam group in each case. For example, each sub-beam of each input beam group can correspond to the number of output beam groups be split accordingly, so that each output beam group is formed from the split sub-beams of each input beam group.

In other words, the partial beams of each input beam group in the beam mixing unit follow a beam path along which one or more optical elements are provided for mixing the partial beams. In particular, the optical elements can split the partial beams of each input beam group and focus them to form the output beam groups. In the beam path, each beam, in particular each sub-beam of a beam group or sub-group, has a beam direction along the beam path. The beam direction defines the propagation direction of the beam.

The second optical arrangement is set up to generate a combined illumination beam from the at least two mixed output beam groups along a beam path. The combined illumination beam has a linear beam profile in the area of the working plane. The combined illumination beam thus generates the defined laser line in the working plane. In other words, the combined illumination beam in the region of the working plane has a beam profile which has a long axis with a long-axis beam width and a short axis with a short-axis beam width perpendicular to the beam direction. The second optical arrangement has a number of optical elements along the beam path, such as lens and/or mirror elements, which are set up to generate the beam profile in the area of the working plane. The second optical arrangement can be movable relative to the working plane along a direction of movement in order to process a workpiece with the aid of the combined illumination beam.

The principle of beam mixing of two individual laser beams has already been U.S. 2006/182155 A1 described. The present invention extends this principle to the mixing of beam groups in order to further minimize the degree of coherence of the illumination.

The line optics system according to the invention comprises the principle of splitting beam groups that are incoherent with one another into a number of parts. These parts are in turn incoherent with one another and are mixed so that the illumination of the line-forming optics is always homogeneous, even if a beam or a group of beams fails. The measure reduces in particular the spatial coherence and the disturbing irregularities are reduced.

The task set at the outset is thus achieved in full.

In a first configuration, the beam mixing unit has at least one beam splitter that is set up to superimpose the at least two input beam groups in order to generate the at least two output beam groups.

As a result, mixing of the input beam groups is achieved in a simple manner. A beam splitter is an optical element that splits a beam into two new beams. A beam splitter can therefore also split a beam group, which consists of several partial beams, into two sub-groups. In this case, each partial beam of the beam group is divided, with a first beam portion of each partial beam running in a first direction and a second beam portion of each partial beam running in a second direction. The beam components of the partial beams in each direction each form a subgroup. When two beam groups meet a beam splitter, the beam groups are superimposed by means of the beam splitter. The two beam groups preferably strike the beam splitter from different directions. In particular, the beam directions of the beam groups are orthogonal to one another. The beam groups are divided in such a way that the beam direction of the generated subgroups is the same. In other words, a subgroup of one beam group always runs in the same beam direction as a subgroup of the other beam group, these subgroups running parallel in turn forming a beam group. In other words, each beam splitter is set up to superimpose two beam groups in such a way that two superimposed beam groups are formed from the two beam groups.

If the number of input beam groups is two, for example, a beam splitter can be provided for mixing. As a rule, the beam is split evenly, which means that the beam splitter divides into equal parts. In other words, the transmission coefficient and the reflection coefficient are equal in this case.

If the number of input beam groups is three, for example, three beam splitters can be provided for mixing. In this case, the beam splitters can have different transmission coefficients and reflection coefficients in order to enable the beam components to be divided evenly.

In a further embodiment, the path length differences through which the partial beams or the beam groups pass in the beam mixing unit are dimensioned in such a way that they are longer than the longitudinal coherence length of the laser light source.

As already explained above, the sub-beams of an input beam group are divided into sub-groups in the beam mixing unit. The beam components of a sub-beam or the sub-groups can then run through different path lengths in the beam mixing unit. The path length difference is longer than the longitudinal coherence length of the laser light source, in particular of the at least one laser beam from which the partial beam was generated in the first optical arrangement. In this way, the spatial coherence is further reduced.

In a further refinement, the beam mixing unit has an adjustment element which is set up to laterally offset one of the input beam groups to be mixed.

As previously explained, each beam group has a beam direction. In this context, the term "lateral" is to be understood as perpendicular to the beam direction of the input beam group. The adjustment element is set up to displace one of the input beam groups laterally, that is to say perpendicularly to its beam direction, before the input groups are mixed. The superimposition of the partial beams in each output beam group can thus be adjusted by means of the adjustment element. As previously explained, the output beam group is formed by several subgroups of the input beam groups. The lateral position of one of the subgroups with respect to the other subgroups in the output beam group is thus adjusted by means of the adjustment element. In other words, by laterally offsetting the partial beams of an input beam group, the corresponding partial beams in each output beam group are also laterally shifted. The adjustment element can thus be used to set how the partial beams are superimposed in each output beam group.

The adjustment element can be a deflection mirror, for example, with the input beam group impinging on the deflection mirror in a first direction and being reflected by the mirror in a second direction. For lateral displacement, the deflection mirror can be moved translationally in the first and/or second direction.

The beam mixing unit can also have a plurality of adjustment elements, each adjustment element being set up to laterally offset one of the input beam groups to be mixed. In particular, an adjustment element can be provided for each input beam group.

In a further refinement, the adjustment element is set up to laterally offset one of the input beam groups to be mixed in such a way that the partial beams in the output beam groups overlap one another.

As explained at the outset, the partial beams in each input beam group run parallel to one another and are spaced apart from one another. The adjustment element can now laterally displace the partial beams of an input beam group in such a way that the corresponding partial beams of the output beam group are in the output beam group in the lateral direction between the other partial beams, so that the partial beams of the output beam group overlap with one another. When the sub-beams in an output beam group overlap, the output beam group has a coherent beam profile. This has the advantage that the following optics, such as a beam transformer, are illuminated more homogeneously. Among other things, the peak intensities are reduced, which is advantageous with regard to the damage threshold and the degradation behavior of the optics. The defined distance between adjacent partial beams is preferably the same in all input beam groups, with the defined distance between adjacent partial beams being smaller than the lateral extent of each partial beam. The sub-groups of the input beam groups can now be offset relative to one another in the lateral direction by means of the adjustment element in such a way that the adjacent sub-beams overlap with one another. In particular, the offset of the sub-groups relative to one another in the lateral direction can correspond to half the offset of the sub-beams in each sub-group.

In a further configuration, the first optical arrangement has at least one beam splitter, the at least one beam splitter being set up to generate a plurality of partial beams from the at least one laser beam.

One or more laser beams are generated by means of the at least one laser light source. Each beam splitter is configured to split a laser beam. In order to generate three or more partial beams from a laser beam, several beam splitters can be arranged one behind the other in the beam path, for example. A plurality of partial beams, which is greater than the number of laser beams, can thereby be generated from the one or more laser beams by beam splitting. In particular, a laser light source can be provided for each input beam group, each of which generates a laser beam. Each laser beam can then be divided into partial beams by means of one or more beam splitters, which form the respective input beam group. Various optical components, for example semi-transparent mirrors or prisms, can be used as beam splitters.

In a further refinement, the first optical arrangement has at least two beam bundle units, each beam bundle unit being set up to bundle at least two of the generated partial beams into one of the input beam groups.

The beam bundle units have, for example, optical components that align the corresponding partial beams of an input beam group parallel to one another, so that they run parallel to one another after they have passed the beam bundle unit. Various optical components, for example mirrors or prisms, can be used as the beam bundle unit.

In a further refinement, the second optical arrangement has at least one beam transformer which is set up to expand the partial beams of the output beam groups in a direction transverse to the beam direction.

With the configuration using a beam transformer, the aspect ratio of the combined illumination beam can be optimized even further and/or even more efficiently with regard to the desired laser line. In this way, the output beam groups can advantageously be expanded in the direction of the long axis. For example, either one beam transformer can be provided for all output beam groups or one beam transformer for each output beam group. The beam transformer can also be called forming optics.

In a further refinement, the second optical arrangement has a—preferably imaging—homogenizer which is set up to distribute the partial beams of the output beam groups homogeneously in the long axis.

The design using a homogenizer facilitates a very homogeneous intensity distribution along the long axis, which is desirable for many applications. In particular, the homogenizer is arranged in the beam path after the beam transformer. The homogenizer can also be called homogenization optics.

In a further refinement, the second optical arrangement has a transformation lens means which is set up to superimpose the output beam groups to form the combined illumination beam.

The transformation lens means are used to shape the beam profile in the working plane. The transformation lens means can have, for example, one or more optical elements (e.g. Fourier lens) along the beam path, which generate the line-shaped beam profile in the area of the working plane. In this case, the optical elements preferably also bring about beam shaping in the short axis. The transformation lens means is arranged in particular in the beam path after the homogenizer. The transformation lens means can also be called a set of large optics.

It goes without saying that the features mentioned above and those still to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

• 1 eine schematische Darstellung eines Ausführungsbeispiels eines neuen Linienoptiksystems;
• 2 eine vereinfachte Darstellung der Bildung einer Eingangsstrahlgruppe;
• 3 eine schematische Darstellung eines Strahlengangs gemäß einem Ausführungsbeispiel des neuen Linienoptiksystems;
• 4 eine schematische Darstellung einer ersten Ausführungsform einer Strahlmischeinheit, die in Ausführungsbeispielen des neuen Linienoptiksystems zum Einsatz kommen kann;
• 5 eine schematische Darstellung einer zweiten Ausführungsform einer Strahlmischeinheit, die in Ausführungsbeispielen des neuen Linienoptiksystems zum Einsatz kommen kann;
• 6 eine schematische Darstellung einer dritten Ausführungsform einer Strahlmischeinheit, die in Ausführungsbeispielen des neuen Linienoptiksystems zum Einsatz kommen kann; und
• 7 eine schematische Darstellung der Strahlmischeinheit aus 6 mit verschobenem Justageelement.

Embodiments of the invention are shown in the drawing and are explained in more detail in the following description. Show it:

• 1 a schematic representation of an embodiment of a new line optical system;
• 2 a simplified representation of the formation of an input beam group;
• 3 a schematic representation of a beam path according to an embodiment of the new line optics system;
• 4 a schematic representation of a first embodiment of a beam mixing unit that can be used in exemplary embodiments of the new line optics system;
• 5 a schematic representation of a second embodiment of a beam mixing unit that can be used in exemplary embodiments of the new line optics system;
• 6 a schematic representation of a third embodiment of a beam mixing unit, which can be used in exemplary embodiments of the new line optics system; and
• 7 a schematic representation of the jet mixing unit 6 with shifted adjustment element.

In 1 an exemplary embodiment of the new line optics system is denoted in its entirety by the reference number 10 . The line optics system 10 generates a laser line 28 in the area of a working plane 29 in order to machine a workpiece (not shown here) that is placed in the area of the working plane 29 . The laser line 28 runs in a direction that is referred to below as the x-axis. The laser line has a line width that is viewed here in the direction of a y-axis running orthogonally to the x-axis. The x-axis corresponds accordingly in the following the one with the long axis and the y-axis corresponds with the short axis of the beam profile formed on the working plane 29. In other words, the beam profile has a long axis with a long-axis beamwidth in the x-direction and a short axis with a short-axis beamwidth in the y-direction. The respective beam width can, for example, be defined as the width of the intensity profile I(x, y) at 50% of the maximum intensity (FWHM, Full Width at Half Maximum) or, for example, as the width between the 90% intensity values (Full Width at 90% Maximum, FW@90% ) or defined in some other way.

In some embodiments, the workpiece may include a surface layer of amorphous silicon that is converted to polycrystalline silicon using laser line 28 . For processing, the laser line 28 can be moved in a direction of movement relative to the working plane 29 . In other exemplary embodiments, the workpiece can be a transparent carrier plate from which an adhering film, for example an OLED film, is to be detached.

The line optics system 10 has at least one laser light source 12 . In preferred exemplary embodiments, the laser light source 12 can be a solid-state laser. Laser light source 12 generates at least one laser beam 20. In preferred embodiments, laser light source 12 can generate a plurality of laser beams. In alternative exemplary embodiments, the line optics system 10 has a plurality of laser light sources 12, with each laser light source 12 generating at least one laser beam 20.

The line optics system 10 also has a first optical arrangement 14 . The first optical arrangement 14 is set up to generate at least two input beam groups 22 from the at least one laser beam 20 . Each input beam group 22 has at least two sub-beams. In each input beam group 22, the partial beams preferably run parallel to one another. Each input beam group 22 preferably has the same number of sub-beams.

In preferred exemplary embodiments, the first optical arrangement 14 has one or more beam splitters, by means of which the at least one laser beam 20 is divided into a plurality of partial beams. Alternatively, if the line optics system 10 has a plurality of laser light sources 12, the number of partial beams can correspond to the number of laser light sources 12, with each laser beam 20 of a laser light source 12 forming a partial beam. Furthermore, the first optical arrangement 14 can have a beam bundle unit for each input beam group 22 , which bundles the partial beams to form the input beam groups 22 .

The line optics system 10 also has a beam mixing unit 16 . The beam mixing unit 16 is set up to mix the at least two input beam groups 22 with one another in order to generate at least two mixed output beam groups 24 . Each output beam group 24 has at least four sub-beams. In each output beam group 24, the partial beams preferably run parallel to one another.

The line optics system 10 also has a second optical arrangement 18 . The second optical arrangement 18 is set up to generate a combined illumination beam 26 from the at least two mixed output beam groups 24 along a beam path. The combined illumination beam 26 defines a beam direction that intersects the working plane 29 . In the region of the working plane 29, the combined illumination beam 26 has a beam profile which, perpendicular to the beam direction, has a long axis with a long-axis beam width and a short axis with a short-axis beam width. In other words, the combined illumination beam 26 has a linear beam profile in the area of the working plane 29 . The combined illumination beam 26 thus generates the laser line 28 in the working plane 29.

In 2 shows how an input beam group 22 is formed according to an embodiment of the new line optics system 10 . The beam group 22 consists, as in 2 shown, from a plurality of partial beams 30 ', 30''and30'', which are brought together via an optical element and run parallel at least over a portion of their path. The optical element can be a beam bundle unit, for example. The partial beams 30', 30'' and 30''' are spaced apart from one another and do not overlap with one another. In 2 three partial beams are shown. In other exemplary embodiments, the input beam group 22 can have a different number of parallel partial beams, in particular two, four or five.

3 shows an exemplary beam path according to an embodiment of the new line optics system 10. Two input beam groups 22', 22'' are connected with the (in 3 not shown) first optical arrangement 14 is generated. The input beam groups 22', 22'' impinge on the beam mixing unit 16. This produces two output beam groups 24', 24'' therefrom. The second optical arrangement 18 is arranged below. The second optical arrangement 18 comprises one or more beam transformers 32, a homogenizer 34 for long-axis beam shaping and a Transformation lens means 36. The components of the second optical arrangement 18 generate in the working plane 29 the linear beam profile mentioned at the outset.

In 4 A first embodiment of the jet mixing unit 16 is shown. The beam mixing unit 16 is designed to generate two output beam groups 24', 24'' from two input beam groups 22', 22''. Such a jet mixing unit 16 can, for example, in the embodiment of 3 be used. The beam mixing unit 16 has a beam splitter 38 which is superimposed on the input beam groups 22', 22''. As a result, the input beam groups 22', 22'' are mixed and correspondingly two output beam groups 24', 24'' are produced.

The beam splitter 38 is rotated by 45° relative to the beam direction of the two input beam groups 22', 22''. The beam directions of the two input beam groups 22', 22'' are orthogonal to one another. In particular, the two input beam groups 22', 22'' meet the beam splitter 38 on different sides. The beam splitter 38 divides each input beam group 22', 22'' into two subgroups, which are superimposed on the two output beam groups 24', 24''. Starting from the beam splitter 38, the beam directions of the two output beam groups 24', 24'' are orthogonal to one another.

The beam mixing unit 16 also has a deflection mirror 40, which deflects the output beam group 24' by 90°. After the deflection, the output beam groups 24', 24'' run parallel to one another. Due to the arrangement of the deflection mirror 40, the output beam group 24' in the beam mixing unit 16 runs through a longer path than the output beam group 24''. The path length difference is preferably dimensioned in such a way that it is longer than the longitudinal coherence length of the laser source. In other words, the two input beam groups 22', 22'' are incoherent with one another at the input. Initially, the output beam groups 24', 24'' comprise a total of four mutually incoherent subgroups.

As a rule, the beam is divided evenly, ie the beam splitter 38 divides into equal parts. Deviations from this are also possible. This is shown using the example of 5 explained below.

In 5 a second embodiment of the jet mixing unit 16 is shown. The beam mixing unit 16 is designed to generate three output beam groups 24', 24'', 24''' from three input beam groups 22', 22'', 22'''. The beam mixing unit 16 has three beam splitters 38', 38'', 38''' which overlay the input beam groups 22', 22'', 22'''. As a result, the input beam groups 22', 22'', 22''' are mixed and correspondingly three output beam groups 24', 24'', 24''' are generated.

The first beam splitter 38' combines the input beam groups 22" and 22"' into first and second mixed beam groups. The second beam splitter 38'' superimposes the input beam group 22' and the first mixed beam group to form the output beam group 24' and a third mixed beam group. The third beamsplitter 38' heterodynes the second mixed beamgroup and the third mixed beamgroup to the output beamgroups 24" and 24"'. On the input side, the three input beam groups 22', 22'', 22''' run parallel to one another. On the output side, the three output beam groups 24', 24'', 24''' also run parallel to one another.

The beam mixing unit 16 also has three deflection mirrors 40', 40'', 40'''. The deflection mirror 40` directs the input beam group 22''' onto the beam splitter 38'. The deflection mirror 40'' directs the second mixed beam group onto the beam splitter 38'''. The deflection mirror 40''' deflects the output beam group 24''' in such a way that it runs parallel to the other output beam groups.

5 thus shows the mixing of three input beam groups 22', 22'', 22'''. In order to achieve a uniform distribution of the beam portions to the output beam groups 24', 24'', 24''', the beam splitters 38' and 38''' have a different transmission than the beam splitter 38''. In general, different transmissions are possible.

Also in the jet mixing unit 5 the subgroups of the input beam groups traverse different paths. The path length differences which the partial beams/groups pass through in the beam mixing unit 16 are dimensioned in such a way that they are greater than the longitudinal coherence length of the laser source, so that the partial beams/groups are incoherent with one another.

In the 6 and 7 a third embodiment of the jet mixing unit 16 is shown. The jet mixing unit 16 of the third embodiment is essentially the same as the jet mixing unit 16 of the first embodiment 4 . The jet mixing unit 16 of the third specific embodiment also has an adjustment element 42 .

The adjustment element 42 is set up to displace the input beam group 22 ″ laterally, ie perpendicular to the beam direction, before the input beam group 22 ″ impinges on the beam splitter 38 . The adjustment element 42 is preferably a deflection mirror that is designed to be movable. The input beam group 22 '' initially runs in a first direction parallel to the input beam group 22'. The input beam group 22'' strikes the folding mirror in the first direction and is then reflected from the mirror towards the beam splitter 38 in a second direction. For lateral displacement, the deflection mirror can be moved translationally in the first and/or second direction. In the embodiment of 6 and 7 the deflection mirror is offset in the first direction. This movement in the first direction is illustrated by arrow 48 .

The adjustment element 42 can thus be used to set the position at which the input beam group 22 ′ impinges on the beam splitter 38 . As a result, the lateral position of the subgroups of the input beam group 22' in the output beam groups 24', 24'' can also be adjusted. In particular, the adjustment element 42 can be used to set how the subgroups of the two input beam groups 22', 22'' are superimposed.

The input beam group 22' has a beam profile 44' and the input beam group 22'' has a beam profile 44''. The beam profile 44', 44'' of each input beam group 22" is formed by the individual partial beams. The partial beams are equidistant from one another in the lateral direction. Adjacent partial beams in each input beam group 22', 22'' have a defined distance from one another. The partial beams do not overlap with each other.The defined distance between adjacent partial beams is smaller than the lateral extent of each partial beam.In the embodiment of FIG 6 and 7 each beam profile 44', 44'' is formed by three partial beams.

The output beam group 24' has a beam profile 46' and the output beam group 24'' has a beam profile 46''. The beam profiles 46', 46'' are formed by superimposing the beam profiles 44', 44''.

In the 6 and 7 the beam profiles 44` and 44'' are essentially identical. This means that both the defined distance between adjacent partial beams and the lateral extent of each partial beam are the same in both beam profiles 44', 44''.

In 6 the lateral position of the input beam group 22'' is set by means of the adjustment element 42 such that the beam profiles 44', 44'' are superimposed such that the partial beams of the subgroups in the output beam groups 24', 24'' coincide. In this way, the beam profiles 46', 46'' essentially correspond to the beam profiles 44', 44''.

In 7 the lateral position of the input beam group 22'' is adjusted by means of the adjustment element 42 in such a way that the beam profiles 44', 44'' are superimposed such that the partial beams in the output beam groups 24', 24'' overlap one another. In particular, the sub-beams of the sub-groups are shifted relative to one another. In particular, the offset of the sub-groups relative to one another corresponds to half the offset of the sub-beams in each sub-group. In other words, the sub-groups are laterally offset from one another in such a way that in each output beam group 24', 24'' a sub-beam of one sub-group is arranged between two sub-beams of the other sub-group and overlaps with them. Each output beam group 24', 24'' thus has in 7 a coherent beam profile.

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

• US2006182155 A1 [0002, 0008, 0019]
• WO 2018/019374 A1 [0006]

Claims (10)

Line optics system (10) for generating a defined laser line (28) on a working plane (29), with: - At least one laser light source (12) for generating at least one laser beam (20); - a first optical arrangement (14), which is set up to generate at least two input beam groups (22, 22', 22'', 22''') from the at least one laser beam (20), each input beam group (22, 22 ', 22'', 22''') has at least two partial beams (30', 30'', 30''); - a beam mixing unit (16) which is set up to mix the at least two input beam groups (22, 22', 22'', 22''') with one another in order to produce at least two mixed output beam groups (24, 24', 24'', 24'''); and - A second optical arrangement (18) which is set up to generate a combined illumination beam (26) from the at least two mixed output beam groups (24, 24', 24'', 24''') along a beam path, the combined The illumination beam (26) defines a beam direction which intersects the working plane (29), the combined illumination beam (28) forming the defined laser line (28) in the area of the working plane. Line optics system (10) according to claim 1 , wherein the beam mixing unit (16) has at least one beam splitter (38, 38', 38'', 38''') which is set up to separate the at least two input beam groups (22, 22', 22'', 22''' ) to be superimposed, in particular in order to generate the at least two output beam groups (24, 24', 24'', 24'''). Line optics system (10) according to claim 1 or 2 , wherein the path length differences that pass through the partial beams or the beam groups in the beam mixing unit (16) are dimensioned such that they are longer than the longitudinal coherence length of the laser light source (12). Line optical system (10) according to one of Claims 1 until 3 , wherein the beam mixing unit (16) has an adjustment element (42) which is set up to laterally offset one of the input beam groups (22, 22', 22'', 22''') to be mixed. Line optics system (10) according to claim 4 , wherein the adjustment element (42) is set up to laterally offset one of the input beam groups (22, 22', 22'', 22''') to be mixed in such a way that the partial beams in the output beam groups (24, 24', 24'',24''') overlap each other. Line optical system (10) according to one of Claims 1 until 5 , wherein the first optical arrangement (14) has at least one beam splitter, wherein the at least one beam splitter is set up to generate a plurality of partial beams from the at least one laser beam (20). Line optical system (10) according to one of Claims 1 until 6 , wherein the first optical arrangement (14) has at least two beam bundle units, each beam bundle unit being set up to bundle at least two of the generated partial beams into one of the input beam groups (22, 22', 22'', 22'''). Line optical system (10) according to one of Claims 1 until 7 , wherein the second optical arrangement (18) has at least one beam transformer (32) which is set up to expand the partial beams of the output beam groups (24, 24', 24'', 24''') in a direction transverse to the beam direction. Line optical system (10) according to one of Claims 1 until 8th , wherein the second optical arrangement (18) has a homogenizer (34) which is set up to distribute the partial beams of the output beam groups (24, 24', 24'', 24''') homogeneously in the long axis. Line optical system (10) according to one of Claims 1 until 9 , wherein the second optical arrangement (18) comprises a transformation lens means (36) arranged to superimpose the output beam groups (24, 24', 24'', 24''') into the combined illumination beam (26).

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