JP7377273B2 - laser system - Google Patents

Description

The present invention relates to a laser system or apparatus for producing a useful light distribution (L) provided by a plurality of laser beams.

An advantageous, but not exclusive, field of application is a useful light distribution with a linear beam profile, in particular an output beam spread along the direction of propagation, extending along the line direction with an intensity that does not disappear in the working plane. The generation of an output beam with a linear beam cross section.

Such a linear beam profile can be used, for example, in the processing of semiconductor or glass surfaces, e.g. in the production of TFT displays, in the doping of semiconductors, in the production of solar cells, or in the production of aesthetically designed glass surfaces for architectural purposes. used for. Here, a linear beam profile is scanned across the surface to be machined perpendicular to the direction of extension of the line. For example, radiation can trigger surface modification processes (recrystallization, melting, diffusion processes) to achieve desired processing results.

The laser system includes multiple laser light sources to provide a desired useful light distribution to produce a high energy density and/or a spatially strongly extended linear intensity distribution. For example, DE 10 2008 027 229 B4 shows a device for beam shaping and combining several laser beams emitted by a plurality of laser light sources and executed in groups over the course of some of their optical channels; In this device, the laser beams can finally be combined and converted into the desired linear beam profile. In order to convert this into a useful light distribution, the laser radiation passes through a plurality of optical elements designed to be illuminated by laser beams from different laser light sources. Therefore, all laser light sources should be activated at all times to achieve uniform illumination of the optical elements. If the laser light source fails or if one attempts to reduce the intensity of the useful light distribution by weakening or deactivating the laser light source, the optical elements are no longer evenly illuminated. This can compromise the quality and homogeneity of the useful light distribution.

DE 10 2008 027 229 B4

The invention is based on the objective of improving the functionality of the laser system and the quality of the useful light distribution when power fluctuations occur or when individual laser sources are deactivated.

This object is achieved by a laser system according to claim 1. A laser system as a whole is a device that includes multiple devices and/or components. In particular, the laser system comprises at least two laser light sources for directing the laser beam and supply optics for the laser beam. The supply optics have at least a first optical input channel and a second optical input channel for the laser beam. Furthermore, the delivery optics comprises at least one first optical output channel and a second optical output channel through which the laser beam exits the delivery optics. The laser beam of the supply optics then continues in the beam path through beam shaping optics designed to form the desired useful light distribution with a rectilinear cross-section from the laser beam of the optical output channel. Run.

The first and second optical input channels are each designed such that they can be provided with input beam groups, and the input beam groups can each include at least two laser beams. The first and second optical output channels are each designed to guide one output beam group, and each output beam group may in turn include at least two laser beams.

The delivery optics are configured such that the delivered laser beam is resorted on the transition from the input channel to the output channel. In particular, the supply optics are configured such that each output beam group includes at least one laser beam from the input beam group of the first optical input channel and one laser beam from the input beam group of the second optical input channel. It acts on

As a result, each output beam group includes contributions from both optical input channels. In particular, a laser beam from one of the input channels is present in each of the output beams. As a result, for example, if the illumination through the optical input channels is reduced (eg, when one of the laser light sources is deactivated), each optical output channel is also illuminated. As a result, the quality and homogeneity of the useful light distribution can be improved, especially if the radiation powers of the various laser sources vary with respect to each other, or if the individual laser sources do not emit at all.

In this context, an optical channel (input channel, output channel) is defined in particular by the fact that groups of laser beams are guided spatially and/or optically separated from other channels within the channel. characterized. An optical channel can include multiple optically effective elements (lenses, mirrors, apertures, etc.). In this respect, the input channel is in particular a section of the supply optics equipped with an optical element that can be irradiated with a laser beam or groups of laser beams and can then run separately from other beams or groups of beams. It is. The different laser beams of the input beam groups are arranged in a supply optics such that each output beam group includes laser beams from at least the input beam group of the first optical input channel and the input beam group of the second optical input channel. redistributed to the output beams.

The feed optics essentially allows each laser beam of the input beam group to pass through the feed optics and be directed into one of the output channels without being mixed with other laser beams of the input beam group. It can be designed to be In this regard, the laser beams are then directed from their respective input beam channels to the output beam channels without being combined with other laser beams. Mixing of different laser beams (e.g. by homogenizing optics, cylindrical lens arrays, etc.) takes place only in such configurations, e.g. in beam shaping optics. In principle, it is conceivable for the various laser beams emitted via the respective optical input channels to travel within the supply optics in mutually separated optical subchannels. Mixing in the optical sense can be avoided, for example, by guiding the laser beams spatially separated from each other in the supply optics. However, the above configuration is not essential.

The supply optics preferably has at least one optical element for each optical input channel, which optical element is designed for beam deflection and/or beam guidance. The optical elements are also configured to detect only one laser beam of the input beams of the respective optical input channel, or only a subgroup of laser beams of the input beams of the respective optical input channel. Set up and placed within the optical system. By means of such optical elements acting selectively only on the laser beams of the input beam group or on the respective subgroups, the laser beams are repositioned in the mentioned manner between the input beam group and the output beam group. be able to.

In particular, the optical element is arranged such that each laser beam that is selectively detected by the optical element, or a subgroup of the laser beams that are selectively detected by the optical element, is not detected by the optical element in the same optical input channel. It is advantageous if it is designed and arranged such that it is guided into a different optical output channel than the For example, it is conceivable that the optical element selectively directs one of the laser beams of the input beam group to a different optical output channel than other laser beams that are not detected.

The supply optics preferably comprises one or more beam steering elements and/or one or more beam guiding elements, by means of which a beam path is defined from the optical input channel to the optical output channel. The beam path preferably has a change in direction, in particular a plurality of changes in direction. It is particularly advantageous if the beam path is folded several times, for example in a Z-fold (similar to the shape of the letter Z). As a result, a long optical path can be accommodated in a compact installation space. This allows, for example, to use telescopes or other beam shaping optics in the beam path with relatively low refractive power and/or relatively large focal lengths. Since optical systems with low refractive strength and/or large focal lengths usually tend to have small aberrations, optical precision can be increased by folding the beam path.

In other embodiments, the particularly folded beam path runs in a plane perpendicular to the plane of the beam path in the subsequent beam shaping optics. In this respect, the beam-shaping optical system also comprises a plurality of optical elements, by means of which the beam path is specified and thereby also preferably has one or more changes in direction, preferably , folded one or more times. In this respect, the folded beam path can now be assigned a plane along which the beam path runs.

The supply optics are preferably such that the first optical input channel and the second optical input channel have, for example, opposite beam directions, in particular laser beams with different beam directions from opposite sides can be emitted into the channels. It is designed to be placed like this. In particular, the supply optics has its own housing, and the beam inlet to the first optical input channel and the further beam inlet to the second optical input channel are arranged on opposite sides of the housing. Ru. These measures make it possible to arrange mutually opposite laser light sources with respect to the supply optics in the laser system. A further beam inlet for a further laser light source can also be provided, which is preferably arranged on a further free side of the housing. As a result, the laser light sources are spatially separated from each other. This increases operational reliability, for example because cooling and power supply are enabled. Maintenance work also becomes easier.

In another embodiment, the supply optics for the at least one optical output channel is configured to change the optical path of the at least one laser beam compared to other laser beams of the respective optical output channel. Includes adjustment optics. Such path conditioning optics are preferably provided for each optical output channel. The optical path conditioning optics is especially designed to receive only one laser beam from the optical output channel or only a subgroup of laser beams from the optical output channel. The optical path adjustment optical system can, for example, have a combination of deflection mirrors, thereby defining an additional variable length optical path. Each detected laser beam or a subgroup of each detected laser beam then traverses this additional variable length optical path.

Advantageously, the system is modular and scalable. In particular, more than one optical input channel can be provided. Alternatively or additionally, the supply optics can be designed to illuminate more than two input beams. Advantageously, the supply optics are designed in such a way that the beam of the input beam group is split into several different output beam groups. Preferably, the supply optics is further designed such that each of the output beam groups includes at least one laser beam from each of the plurality of input beam groups. Such systems are substantially uniformly illuminated even when one or more laser sources are deactivated.

In other embodiments, the beam shaping optics include reshaping optics that receive the laser beam emerging from the optical output channel. The reshaping optics are designed to form a beam package with a beam cross section extending linearly from the detected laser beam. For this purpose, it is conceivable that the reshaping optical system has several separate conversion elements, one conversion element each being assigned to a respective output beam group. Each output beam group, as explained, includes contributions from several input channels, so that the shaping optics are uniformly illuminated even when the laser source is not irradiating a laser beam.

However, designs with separate transformation elements are not required. It is also conceivable that the output beams are combined to form a combined beam in front of the reshaping optics. In this respect, the beam shaping optics may be a combination optics set to combine the laser beams of the output beam groups of the respective optical output channels, or the output beams of several optical output channels before the reshaping optics. It may further include a combination optic configured to combine the laser beams from the groups to form a combination beam. The reshaping optics are preferably arranged such that they then receive the combined beams and reshape them into a beam package having a linearly extending beam cross section.

For further refinement, a homogenization optic can be provided downstream of the beam path, i.e. following the reshaping optics, which is used to provide the desired properties to the useful light distribution. The system's beam packets are detected and further reshaped.

The laser beams of the output beam group can optionally be optically shaped independently of each other in beam shaping optics. For this purpose, it is conceivable that the beam shaping optics comprises at least one telescope, in particular an anamorphic telescope, which acts on one or more laser beams of the optical output channel. The telescope may in particular be equipped with two converging lenses following each other in the beam path, such that, for example, from their additive focal lengths, their opposing focal planes coincide (e.g. the Kepler telescope). (in the manner of) placed at a distance. The telescope is preferably designed as an anamorphic telescope, so that the laser beam is anamorphically transformed in each channel. In particular, the telescope is designed to produce an image-scale cylindrical distortion along an axis perpendicular to the direction of propagation of the laser beam. For example, beam shaping optics are arranged in series in the beam path for each output beam group or for a group of output beams acting with respect to two different distortion directions (in particular with respect to two perpendicular directions). It is conceivable to have two anamorphic telescopes. In this way, the properties of the beam can be adjusted about two vertical axes. The telescope described here is specifically placed in the beam path before the reshaping optics.

An advantageous aspect of the invention is that different laser light sources are fed into different optical input channels. Since each optical output channel directs the laser beam from some or all input channels, even if the laser light source fails, the optical output channels will still be uniformly illuminated. Therefore, the laser light sources can be operated independently of each other.

An advantageous aspect of the invention also consists in the fact that each laser light source is designed to emit at least two separate (ie spatially separated from each other) laser beams. In particular, it is then provided that the two laser light sources are emitted into different light input channels, and that the at least two laser lights emitted by one laser light source form an input beam group. Such a laser light source can be implemented, for example, as a frequency-doubled laser or a frequency-doubled laser, in which the remaining converted beam is also reconverted, thus providing two or more output beams. I can do it.

The invention will be explained in more detail below with reference to the drawings.

FIG. 1 is a schematic diagram for explaining the beam path and functional components of a laser system according to the invention. FIG. 2 is a perspective view of a compactly constructed laser system according to the invention.

In the following description and figures, the same reference symbols are used for identical or mutually corresponding features.

1 and 2, a laser system or apparatus is shown, generally designated by the reference numeral 10. In FIGS. In the illustrated example, laser system 10 includes two laser light sources 12a, 12b for emitting laser beams. In the illustrated example, each of the laser light sources 12a, 12b is designed such that two separate laser beams 14 are emitted in parallel.

Laser light from each laser light source 12a, 12b forms input beam groups 16a, 16b, respectively. It goes without saying that the input beams can also be provided by a plurality of laser sources, each emitting only one laser beam 14, for example. Input beams 16a, 16b are emitted into feed optics 20 through optical input channels 18a and 18b, respectively. In this regard, the supply optics 20 has an associated beam inlet 22a or 22b for each optical input channel 18a or 18b (see FIG. 2). The optical input channel 18a or 18b may, for example, have suitable optical elements or devices for coupling the laser beam to the supply optics 20.

The supply optical system 20 also has first and second optical output channels 24a and 24b, respectively. In the supply optics 20, the laser beam 14 irradiated through the first and second optical input channels 18a, 18b is directed to optical output channels 24a and 24b in a manner described in more detail below. In this regard, output beam groups 26a and 26b of laser beam 14 are provided in first and second optical output channels 24a, 24b, respectively.

The output beams 26a, 26b emitted from the optical output channels 24a, 24b are then received by beam shaping optics 28 and converted into the desired useful light distribution L. The illustrated example has a linear beam cross section.

In order to shape the linear useful light distribution L from the laser beam 14 of the output beam groups 26a, 26b, the beam shaping optics 28 typically comprises various optically functional devices. For example, it is conceivable that the laser beams of the output beam groups 26a or 26b, or subgroups thereof, first pass through one or more telescopes 30. Such a telescope 30 can be designed in particular anamorphically, so that the beam cross section is preshaped in a suitable manner.

Following the beam path, the laser beam 14 is then guided through a reshaping optics 32 that forms one or more beam packets with elongated beam cross-sections from the laser beam 14 of the output beam groups 26a, 26b, for example. Ru. The beam packets preformed in this way can be mixed, for example with homogenizing optics 34, and smoothed in their intensity profile, so as to provide the desired useful light distribution L.

The reshaping optics 32 can in principle have several separate conversion elements 33 (see FIG. 1). For example, it is conceivable that one conversion element 33 each acts on the laser beam 14 from only one of the output beam groups 26a, 26b. However, this configuration is not required. The reshaping optical system 32 may also include a common conversion element for all laser beams of the output beam groups 26a, 26b. In this case, the beam shaping optics 28 may have a combination optic connected upstream of the reshaping optics that combines the laser beams of the various output beam groups 26a, 26b into a combined beam. According to one embodiment (see FIG. 1), the beam shaping optics 28 may also include a combination optics 35 that combines the laser beams of the output beam groups 26a, 26b of the respective optical output channels 24a, 24b.

The supply optics 20 has a plurality of beam steering and/or beam guiding elements 36 by means of which a beam path 38 is predefined within the supply optics 20 . In the illustrated example, the beam path 38 is folded several times, so that a relatively long optical path can be covered with a compact installation space, and therefore optical elements (not shown in detail) for shaping the beam properties are used. Sufficient space is provided for.

The supply optics 20 is designed such that the laser beams 14 of the input beam groups 16a, 16b initially run separate from each other and separately from the laser beams of the respective other input beam groups. . In the illustrated example, the supply optics 20 also include an optical element 40 (here a deflection mirror) for beam deflection and/or beam guidance, which is used for one laser beam of each input beam group 16a or 16b. Affects only the beam.

The optical element 40 is designed to direct the detected laser beams to the respective other optical output channels 24a or 24b rather than the laser beams 14 of the respective input beam groups 16a or 16b not being detected by the optical element 40. . This means that each output beam group 26a, 26b receives at least one laser beam 14 from the input beam group 16a of the first optical input channel 18a and from the input beam group 16b of the second optical input channel 18b, respectively. at least one laser beam 14. In this regard, the supply optics 20 has the laser beams 14 grouped into two input beam groups 16a and 16b such that they run in different pairs in the respective output beam groups 26a, 26b of the optical output channels 24a, 24b. Designed to relocate.

The supply optical system 20 can also include a path adjustment optical system 42 that can change the optical path of at least one laser beam with respect to other laser beams 14. This makes it possible to provide desired operation to the laser system 10 over time, for example, during operation by the pulsed laser light sources 12a, 12b.

As can be seen in FIG. 2, the laser system 10 has a particularly modular construction. In particular, the supply optics 20 and/or the beam shaping optics 28 may each have their own module housing 44 . Due to the modular structure, a compact system can be constructed with a relatively small installation space. For this purpose, it is particularly advantageous if the beam paths in the supply optics 20 and in the beam shaping optics 28 are not linearly adjacent to each other but are instead in an angled or folded configuration. It is. In the illustrated example, the beam path 38 in the supply optics 20 is folded several times and extends in one plane (see FIG. 1). The module housing 44 of the supply optics 20 is therefore a flat cubic or box-shaped housing (i.e. with an extension perpendicular to said plane that is smaller than an extension parallel to said plane). It can be molded as The laser beams provided in the optical output channels 24a, 24b (output beam groups 26a, 26b) can then be passed in another direction. For example, beam shaping optics 28 may have a beam path extending in a plane essentially perpendicular to beam path 38 of supply optics 20 (see FIG. 1).

In the illustrated example, the beam inlets 22 a , 22 b for the first optical input channel 18 a and the second optical input channel 18 b are located on different sides of the module housing 44 of the supply optics 20 . For example, the laser light sources 12a, 12b can be placed opposite each other with respect to the supply optics 20 and emit in opposite beam directions. The various laser light sources can of course also be arranged such that their respective beam directions enclose acute or obtuse angles with respect to each other. The laser light sources may also have parallel beam directions and may be arranged vertically offset from each other, for example. According to a general aspect, the various laser light sources 12a, 12b are arranged such that their housings are spaced apart from each other. In this way, work on one of the two laser light sources can be performed without affecting the other laser light source. It also made possible a compact structure.

Claims (13)

A laser system (10) for producing a useful light distribution (L) with a straight beam cross section provided by a plurality of laser beams (14), comprising:
at least two laser light sources (12a, 12b) for emitting a laser beam (14);
comprising at least a first optical input channel (18a) and a second optical input channel (18b), a first optical output channel (24a) and a second optical output channel (24b) for the laser beam (14). ), a supply optical system (20) having
beam shaping optics (28) for shaping a useful light distribution (L) from the laser beam (14) of the light output channels (24a, 24b);
Equipped with
The first optical input channel (18a) and the second optical input channel (18b) are arranged to provide one input beam group (16a, 16b) each comprising at least two laser beams (14). The first optical output channel (24a) and the second optical output channel (24b) are designed to provide one output beam group (26a, 26b) each including at least two laser beams (14). Designed to guide you;
and a supply optical system (20) for one output beam group (26a) guided from said first optical output channel (24a) and the other output beam group guided from said second optical output channel (24b). Each of the groups (26b) includes at least one laser beam (14) from the input beam group (16a) of the first optical input channel (18a) and the input beam group (16b) of the second optical input channel (18b). ) designed to reposition the supplied laser beam (14) to include at least one laser beam (14) from
The distance between the one output beam group (26a) and the other output beam group (26b) is the distance between the plurality of laser beams in the one output beam group (26a) and the distance between the other output beam group (26a). A laser system (10) characterized in that the distance is longer than the distance between the plurality of laser beams in the group (26b) . The supply optics (20) for each optical input channel (18a, 18b) comprises at least one optical element (40) for beam deflection and/or beam guidance, said optical element (40) comprising: Only one laser beam (14) of the input beam groups (16a, 16b) of each optical input channel (18a, 18b) or only one laser beam (14) of the input beam group (16a, 16b) of each optical input channel (18a, 18b) Laser system (10) according to claim 1, designed and arranged in such a way that only subgroups of laser beams (14) are guided. Said optical element (40) is configured such that a guided laser beam (14) or a subgroup of guided laser beams (14) of each optical input channel (18a, 18b) is not guided by said optical element (40). Laser system (10) according to claim 2, designed to enter the laser beam (14) of the same optical input channel (18a, 18b) into a separate optical output channel (26a, 26b). The supply optics (20) includes a beam steering element (36) and/or a beam for defining a beam path (38) from the optical input channel (18a, 18b) to the optical output channel (24a, 24b). Claim characterized in that it has a guiding element (36) and that said beam path (38) has at least one change of direction or multiple changes of direction and is further folded several times. The laser system (10) according to any one of items 1 to 3. 4 . The supply optics ( 20 ) are designed such that the beam path ( 38 ) runs in a plane perpendicular to the plane in which the beam path in the beam shaping optics ( 28 ) runs. The laser system (10) described in (10). The supply optical system (20) supplies a first optical input channel (18a) and a second optical input channel (18b) with laser beams (14) having different and opposite beam directions. Laser system (10) according to any one of claims 1 to 5, characterized in that it is designed to. The supply optics (20) for at least one light output channel (24a, 24b) comprises a path conditioning optical system (42), said path conditioning optics (42) providing for at least one light output channel (24a, 24b). Laser system (10) according to any of the preceding claims, configured to provide an optical path of at least one laser beam (14) compared to other laser beams (14). Two or more optical input channels (18a, 18b) are provided and/or two or more input beam groups (16a, 16b) are provided, and the supply optics (20) is configured to provide an output beam group (26a, 16b). , 26b) is designed to contain each of at least one laser beam (14) from the respective input beam group (16a, 16b). laser system. The beam shaping optics (28) receive the laser beams (14) of the optical output channels (24a, 24b) and convert them into beam packages having a linear expanded beam cross section. ). Laser system (10) according to any one of claims 1 to 8. The beam-shaping optics (28) is arranged to form a laser beam (14) of output beams (26a, 26b) from an optical output channel (24a, 24b) or output beams from a plurality of optical output channels (24a, 24b). further comprising a combining optical system (35) configured to combine the laser beams (14) of (26a, 26b) into a combined beam in front of the reshaping optical system (32), the reshaping optical system 10. The laser system of claim 9, wherein (32) is designed and arranged to receive the combined beam. 11. The beam shaping optics (28) comprises at least one anamorphic telescope (30) acting on one or more laser beams (14) of the optical output channels (24a, 24b). Laser system (10) according to any one of the items. Laser system (10) according to any of the preceding claims, characterized in that different laser light sources (12a, 12b) are fed into different optical input channels (18a, 18b). 13. Each laser light source (12a, 12b) is designed to provide at least two separate laser beams (14) and emit into different optical input channels (18a, 18b). The laser system (10) according to item 1.