WO2020156821A1

WO2020156821A1 - Laser system

Info

Publication number: WO2020156821A1
Application number: PCT/EP2020/050985
Authority: WO
Inventors: Silke Thierfelder; Christoph Tillkorn; Torsten Beck; Julian Hellstern; Andreas Heimes; Christian LINGEL; Felix MARSCHALL
Original assignee: Trumpf Laser- Und Systemtechnik Gmbh
Priority date: 2019-01-31
Filing date: 2020-01-16
Publication date: 2020-08-06
Also published as: TW202036094A; CN113366375A; JP2022520002A; KR20210120045A; DE102019102511A1; JP7377273B2; CN113366375B; TWI722760B; DE102019102511B4

Abstract

The invention relates to a laser system (10) having two laser light sources (12a, 12b), an input optical unit (20) having two optical input channels (18a, 18b) and two output channels (24a, 24b), and a beam forming optical unit (28) for forming the useful light distribution (L). The optical input channels are each designed to feed one input beam group (16a, 16b) each, each comprising at least two laser beams (14), and the optical output channels are designed to guide one output beam group (26a, 26b) each. The input optical unit (20) is designed to resort the fed laser beams (14) such that each output beam group (26a, 26b) comprises at least one laser beam (14) from the input beam group (16a) of the first optical input channel (18a) and at least one laser beam (14) from the input beam group (16b) of the second optical input channel (18b).

Description

Title: Laser system

description

The invention relates to a laser system and a

Laser device for generating a useful light distribution (L) which is fed by several laser beams.

An advantageous, but not exclusive

The field of application is the generation of a

Useful light distribution with a line-like beam profile, in particular an output beam, which spreads out along a direction of propagation and which in a working plane has a line-like line, along a

Extended beam cross-section with line direction

non-vanishing intensity. Such line-like beam profiles are used, for example, in the processing of surfaces of semiconductors or glasses, for example in the production of TFT displays, in the doping of semiconductors, in the

Manufacture of solar cells or for the production of aesthetically designed glass surfaces for building purposes. Here, the line-like beam profile is perpendicular to

Direction of expansion of the line scanned over the surface to be machined. Through the radiation can

for example superficial conversion processes

(Recrystallization, melting, diffusion processes) are triggered and the desired processing results are achieved.

The laser systems comprise a plurality of laser light sources for supplying the desired useful light distribution in order to generate a high energy density and / or a spatially extensive linear intensity distribution.

For example, DE 10 2008 027 229 B4 shows one

Device for beam shaping and combination of a plurality of laser beams which are emitted by a plurality of laser light sources and which each run a part of their way in groups in separate optical channels, the

Laser beams then ultimately merged and into a light distribution with the desired, line-like

Beam profile can be converted. In order to convert it into the distribution of useful light, the laser radiation passes through a number of optical elements, which are added to it

are designed by the laser beams of different Laser light sources are illuminated. To ensure uniform illumination of the optical elements

all laser light sources should therefore always be in operation. If a laser light source fails, or if the intensity of the useful light distribution is to be reduced by weakening or deactivating a laser light source, the optical elements are no longer illuminated uniformly. This can affect the quality and homogeneity of the useful light distribution.

The invention is based, which

Functionality of the laser systems and the quality of the

To improve useful light distribution in the event of power fluctuations or when individual laser light sources are deactivated.

This object is achieved by a laser system according to claim 1. The laser system as a whole is a device which comprises several devices and / or components. In particular, the laser system comprises at least two laser light sources for specifying

Laser beams and a feed optic for the

Laser beams. The feed optics have at least a first optical input channel and a second optical input channel for the laser beams. In addition, the feed optics include at least a first optical output channel and a second optical output channel through which the laser beams emerge from the feed optics. The laser beams of the feed optics

then run in the beam path through a

Beam shape optics, which are used to shape the desired Useful light distribution with a linear cross section is formed from the laser beams of the optical output channels.

The first and the second optical input channel are each designed in such a way that an input beam group can be fed in, wherein an input beam group can comprise at least two laser beams. The first and the second optical output channel are each designed to guide one output beam group each, wherein each output beam group can in turn comprise at least two laser beams.

The feed optics are set up in such a way that the laser beams fed in during the transition from the

Input channels are sorted into the output channels. In particular, the feed optics act in such a way that each output beam group has at least one laser beam from the input beam group of the first

optical input channel and a laser beam from the input beam group of the second optical input channel.

As a result, each output beam group contains contributions from both optical input channels. In particular, a laser beam from one of the input channels is present in each of the output beam groups. This means that each optical output channel is also illuminated when, for example, the radiation from an optical one

Input channel is reduced (for example, if one of the laser light sources is deactivated). This allows the The quality and homogeneity of the useful light distribution can be improved, in particular if the radiation power of the different laser light sources is relative to one another

is changed or individual laser light sources do not emit at all.

In the present context, an optical channel (input channel, output channel) is distinguished in particular by the fact that a group of laser beams is guided in the channel in a spatially separated and / or optically separate manner from the other channels. An optical channel can

Include a plurality of optically active elements (lenses, mirrors, diaphragms, etc.). In this respect, the input channel is in particular a section of the feed optics

Optical elements through which a laser beam or a group of laser beams can be irradiated and then run separately from other beams or groups of beams. The different laser beams of the

In this respect, input beam groups are in the

Infeed optics newly distributed to the output beam groups in such a way that each output beam group comprises 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.

The feed optics can basically be like this

trained that each laser beam one

Input beam group without mixing with the other laser beams of this input beam group

Feed optics passes through and into one of the Output channels is guided. In that respect they would

Laser beams are not yet combined with other laser beams from the respective input beam channel to

Output beam channel directed. A mix

different laser beams (for example by means of

Homogenization optics, cylindrical lens arrays or

Similar) takes place in such configurations

for example, only in the beam shape optics. In principle, it is conceivable that the different laser beams that are irradiated through a respective optical input channel run in the feed optics in separate optical subchannels. A

Mixing in the optical sense can be avoided, for example, in that the laser beams are guided in the feed optics at a spacing from one another. However, the above-mentioned configurations are not mandatory.

The feed optics preferably have for everyone

optical input channel at least one optical element, which for beam deflection and / or beam guidance

is trained. The optical element is also to this

set up and so in the feed optics

arranged that there is only one laser beam

Input beam group of the respective optical

Input channel or only a subset of laser beams of the input beam group of the respective optical

Input channel detected. By means of one

Optical elements, which only selectively on a laser beam of an input beam group or on a respective one Subgroup acts, the laser beams in the

can be resorted between the input beam groups and the output beam groups.

In particular, it is advantageous if the optical element is designed and arranged in such a way that the laser beam selectively detected by the optical element or the subgroup of selectively detected by the optical element

Laser beams is guided into a different optical output channel than the laser beams of the same optical input channel that are not detected by the optical element. It is conceivable, for example, that the optical element selectively directs one of the laser beams of an input beam group to a different output channel than the others

detected laser beams.

The feed optics preferably comprise one or more beam steering elements and / or one or more

Beam guiding elements, by means of which a beam path from the optical input channels to the optical

Output channels is defined. The beam path preferably has a change in direction and in particular a plurality of changes in direction. In particular is

advantageous if the beam path is folded several times, for example in the manner of a Z-fold

(similar to the shape of the letter Z). This allows a long optical path to be accommodated in a compact installation space. This makes it possible, for example, in the

Beam path telescopes or other beam shaping optics with comparatively low refractive power and / or use comparatively large focal lengths. There

Usually aberrations for optics with less

If the refractive power and / or large focal lengths tend to be low, the optical precision can be increased by folding the beam path.

For a further embodiment, the in particular folded beam path runs in a plane that is perpendicular to the plane of the beam path in the following one

Beam shape optics is. In this respect also includes

Beam shape optics a plurality of optical elements, by means of which a beam path is specified, which in particular likewise has one or more changes in direction

is preferably folded one or more times. In this respect, a level in which the beam path runs can in turn be assigned to the folded beam path.

The feed optics are preferably designed such that the first optical input channel and the second optical input channel are arranged such that

Laser beams with different beam directions, for example with opposite beam directions and in particular from opposite sides can be irradiated into the channels. In particular, the

Infeed optics have their own housing, with a

Beam access to the first optical input channel and a further beam access to the second optical

Input channel are arranged on opposite sides of the housing. These measures make it possible

Laser sources opposite each other with respect to the Arrange feed optics in the laser system. Further beam accesses can also be provided for further laser light sources, which are arranged in particular on further free sides of the housing. That’s why

Laser light sources spaced apart. This increases operational safety, since cooling and power supply are made possible, for example. Also be

Maintenance work simplified.

For a further embodiment, the feed optics for at least one optical output channel

Path adjustment optics, which are set up to change the optical path of at least one laser beam in comparison to other laser beams of this respective output channel. Is preferred for everyone optical

Such a path adjustment optics provided output channel. The path adjustment optics is designed in particular in such a way that it detects only one laser beam of the output channel or only a subset of laser beams of the output channel. A path adjustment lens can, for example, have a combination of deflecting mirrors, by means of which a length-adjustable additional optical path can be defined. The respectively detected laser beam or the respectively detected subgroup of laser beams then runs through this variable additional path.

The system is modular and advantageous

built scalable. In particular, more than two optical input channels can be provided. Alternatively or additionally, the feed optics can be designed in this way be that more than two input beam groups can be irradiated. The feed optics are advantageously designed such that the beams of a

Input beam group on several different ones

Output beam groups can be divided. The

Feed optics are further preferably such

formed that each of the output beam groups each have at least one laser beam from each of the plurality

Includes input beam groups. Such a system is still largely homogeneously illuminated when one or more laser light sources are deactivated.

For a further refinement, the beam shaping optics have shaping optics which detect the laser beams which emerge from the optical output channels. The shaping optics are designed to form a beam package with a beam cross section that is extended in a line-like manner from the detected laser beams. For this purpose, it is conceivable that the shaping optics have several separate conversion elements, one each

Conversion element is assigned to a respective output beam group. Since each output beam group contains contributions from several input channels, as explained, the shaping optics are illuminated homogeneously even when a laser source is not emitting.

However, designing with separate conversion elements is not mandatory. It is also conceivable that the

Output beam group in front of the forming optics into one

Combination beam can be combined. In this respect, the beam shape optics can additionally comprise combination optics, which is set up to block the laser beams

Output beam group of a respective output channel or laser beams from output beam groups of several

Output channels in front of the forming optics into one

Merge combination beam. The shaping optics is preferably arranged such that it then has the

Combination beam captured and converted into a beam package with a linear beam cross section.

To further refine the beam path

subordinate, i.e. following the forming optics, a homogenizing optic can also be provided, which the

Beam packets from the forming optics are recorded and further formed in order to give the useful light distribution the desired properties.

The laser beams of the output beam groups can optionally be optically shaped independently of one another in the beam shaping optics. It is conceivable that the

Beam shape optics has at least one telescope, in particular anamorphic telescope, which acts on one or more laser beams of an optical output channel. A telescope can in particular have two in the beam path

successive converging lenses include which

for example, are arranged at a distance from their added focal lengths, so that they face each other

Focal planes collapse (like a Keppler telescope). Preferably the telescope is as

anamorphic telescope designed so that

Laser beams are deformed anamorphically in the respective channel. In particular, the telescope is designed to a cylindrical distortion of the imaging scale along an axis perpendicular to the direction of propagation of the

To effect laser beams. It is conceivable, for example, that the beam shape optics for each output beam group or for certain output beam groups have two anamorphic telescopes arranged serially in the beam path, which telescopes are different

Distortion directions are effective (especially with regard to two vertical directions). This allows the

Beam properties can be set with respect to the two vertical axes. The telescopes mentioned are

especially in the beam path in front of the forming optics

arranged.

An advantageous aspect of the invention is that the different laser light sources in each case

feed in different optical input channels. Since a respective output channel carries laser beams from several or all input channels, the output channel is still homogeneous even if a laser light source fails

illuminated. The laser light sources can therefore

operated independently of each other.

An advantageous aspect of the invention also consists in that each laser light source for emitting at least two separate (i.e. spatially separated from one another

extending) laser beams is formed. In particular, it is then provided that the two laser light sources radiate into different optical input channels, the at least two being emitted by a laser light source Laser beams form an input beam group. Such laser light sources can, for example, as

frequency-doubled or frequency-multiplied lasers can be realized, in which the conversion residual beam is also fed to a new conversion and thus two or more output beams can be provided.

The invention is explained in more detail below with reference to the figures.

Show it:

Figure 1 sketched representation to explain the

Beam path and the functional components of a laser system according to the invention;

Figure 2 perspective view of an inventive

Laser system with a compact design.

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

In Figures 1 and 2 is a laser system and a

Laser device shown, the total with the

Reference numeral 10 is designated. In the example shown, the laser system 10 comprises two laser light sources 12a, 12b for emitting laser beams. In the example shown, each of the laser light sources 12a, 12b is designed such that that two separate laser beams 14 are emitted in parallel.

The laser beams from each laser light source 12a, 12b each form an input beam group 16a or 16b. It goes without saying that the input beam groups can also be fed by several laser light sources,

for example, from several laser light sources, each of which emits only one laser beam 14. The

Input beam groups 16a, 16b are each passed through an optical input channel 18a and 18b, respectively

Infeed optics 20 irradiated. In this respect, the

Infeed optics 20 have an associated beam access 22a or 22b for each optical input channel 18a or 18b (see FIG. 2). An optical input channel 18a or 18b can, for example, have suitable optical elements or optical devices for coupling the laser beams into the feed optics 20.

The feed optics 20 also have a first and a second optical output channel 24a or 24b. In the feed optics 20, the laser beams 14 irradiated through the first and second optical input channels 18a, 18b become even closer in the following

described way to the optical

Output channels 24a and 24b passed. In this respect, an output beam group 26a or 26b of laser beams 14 is provided on each of the first and second optical output channels 24a, 24b. The output beam groups 26a, 26b emerging from the optical output channels 24a, 24b are then replaced by one

Beam shape optics 28 captured and in the desired

Formed useful light distribution L, which in the example shown has a linear beam cross section.

In order to form the line-shaped useful light distribution L from the laser beams 14 of the output beam groups 26a, 26b, the beam shaping optics 28 usually comprise various optically functional devices. Is conceivable

for example, that the laser beams of the

Output beam groups 26a or 26b or subgroups thereof first pass through one or more telescopes 30. Such telescopes 30 can in particular be anamorphic, so that the beam cross section in FIG

is suitably preformed. De

Following in the beam path, the laser beams 14 are then e.g. passed through a shaping optics 32, which from the laser beams 14 of the output beam groups 26a, 26b one or more beam packets with an elongated

Shape the beam cross section. The beam bundles preformed in this way are e.g. mixed with homogenization optics 34 and smoothed in the intensity curve so that the desired useful light distribution L can be provided.

The forming optics 32 can in principle have a plurality of separate conversion elements 33 (cf. FIG. 1). It is conceivable, for example, that one conversion element 33 each onto the laser beams 14 from only one of the Output beam groups 26a, 26b act. However, this configuration is not mandatory. The shaping optics 32 can also comprise a common conversion element for all laser beams of the output beam groups 26a, 26b. In this case, the beam shaping optics 28 can be one of the shaping optics

have upstream combination optics which combine the laser beams of the different output beam groups 26a, 26b to form a combination beam. The

According to one embodiment (cf. FIG. 1), beam shaping optics 28 can also have combination optics 35 which combine the laser beams of an output beam group 26a, 26b of a respective output channel 24a, 24b.

The feed optics 20 have a plurality of

Beam guiding elements and / or beam guiding elements 36, by means of which a beam path 38 in the

Feed optics 20 is predetermined. In the illustrated

For example, the beam path 38 is folded several times, so that a comparatively long optical path can be covered in a compact installation space, and so sufficient space is provided for optical elements (not shown) for shaping the beam properties.

The feed optics 20 are designed such that the laser beams 14 of an input beam group 16a, 16b initially run separately from one another and also separately from the laser beams of the respective other input beam group. In the example shown, the feed optics 20 also include an optics element 40 for beam deflection and / or beam guidance (here: deflection mirror), which is only on one laser beam each

Input beam group 16a or 16b acts.

The optical element 40 is designed such that it directs the detected laser beam into the respective other optical output channel 24a or 24b than that of the

Optical element 40 not detected laser beams 14 of the respective input beam group 16a or 16b. This ensures that each output beam group 26a, 26b each has at least one laser beam 14 from the

Input beam group 16a of the first optical

Includes input channel 18a and at least one laser beam 14 from the input beam group 16b of the second optical input channel 18b. In this respect it is

Feed optics 20 designed to rearrange the laser beams 14 grouped into the two input beam groups 16a and 16b so that they run in a different pairing in the respective output beam groups 26a, 26b of the optical output channels 24a, 24b.

The feed optics 20 can also be a

Path adjustment optics 42 comprise, by means of which a

optical path of at least one laser beam can be changed in comparison to the other laser beams 14. This

makes it possible, for example, to give the laser system 10 a desired temporal behavior in operation with pulsed laser light sources 12a, 12b.

As can be seen in FIG. 2, the laser system 10

especially modular. In particular, the Feed optics 20 and / or beam shaping optics 28 each have their own module housing 44. Due to the modular structure, a compact system can be used

comparatively small space can be built. For this purpose, it is particularly advantageous if the beam paths in the feed optics 20 and in the beam shaping optics 28 do not connect linearly to one another, but one

angled or folded configuration takes place. in the

The example shown is the beam path 38 in FIG

Feed optics 20 folded several times and extending in one plane (see FIG. 1). Accordingly, the module housing 44 of the feed optics 20 can be shaped as a flat, cuboid or box-like housing (i.e. with an extent perpendicular to the plane mentioned, which is less than the dimension parallel to the plane). The laser beams (output beam group 26a, 26b) provided in the optical output channels 24a, 24b can then in turn be passed on in another direction. For example, the beam shape optics 28 can have a beam path that is in one plane

extends substantially perpendicular to the

Beam path 38 of the feed optics 20 (see FIG. 1)

In the example shown, the beam accesses 22a, 22b for the first optical input channel 18a and the second optical input channel 18b are arranged on different sides of the module housing 44 of the feed optics 20.

For example, the laser light sources 12a, 12b can be mutually related with respect to the feed optics 20 be arranged opposite each other and emit in opposite beam directions. The different

Laser light sources can of course also be arranged such that their respective beam directions form an acute or obtuse angle with one another. The laser light sources can also use parallel ones

Beam directions and e.g. be vertically staggered. In a general aspect, the various laser light sources 12a, 12b are arranged such that their housings are spaced apart. Work on one of the two laser light sources can thus take place without the other laser light source being affected.

In addition, a compact structure is made possible.

Claims

1. Laser system (10) for generating one of several

Laser beams (14) fed useful light distribution (L) with a linear beam cross section, comprising:

- at least two laser light sources (12a, 12b) for emitting the laser beams (14);

- A feed optics (20) with at least a first optical input channel (18a) and a second optical input channel (18b) for the laser beams (14) and with at least a first optical

Output channel (24a) and a second optical

Output channel (24b) for the laser beams (14),

- A beam shape optics (28) for shaping the

Useful light distribution (L) from the laser beams (14) of the optical output channels (24a, 24b),

characterized in that the first (18a) and the second (18b) optical input channel each for

Feeding in each of an input beam group (16a, 16b) each comprising at least two laser beams (14), and that the first (24a) and second (24b) optical output channels each for guiding one output beam group (26a, 26b) each comprising at least two laser beams (14) are formed,

and that the feed optics (20) are set up to rearrange the fed laser beams (14) in such a way that each output beam group (26a,

26b) at least one laser beam (14) the input beam group (16a) of the first optical input channel (18a) and at least one laser beam (14) from the input beam group (16b) of the second optical input channel (18b).

2. Laser system (10) according to one of the preceding claims, wherein the feed optics (20) for each optical input channel (18a, 18b) has at least one optical element (40) for beam deflection and / or beam guidance, which is designed and arranged such that the optical element (40) only one laser beam (14) of the input beam group (16a, 16b) of the respective optical input channel (18a, 18b) or only a subset of laser beams (14) of the

Input beam group (16a, 16b) of the respective

optical input channel (18a, 18b) detected.

3. Laser system (10) according to claim 2, wherein the

Optical element (40) is designed such that the detected laser beam (14) of the respective optical input channel (18a, 18b) or the detected one

Subgroup of laser beams (14) reaches a different optical output channel (26a, 26b) than those not detected by the optical element (40)

Laser beams (14) of the same optical input channel (18a, 18b).

4. Laser system (10) according to any one of the preceding claims, wherein the feed optics (20)

Beam steering elements (36) and / or

Beam guiding elements (36) for defining a Beam path (38) from the optical input channels (18a, 18b) to the optical output channels (24a, 24b), the beam path (38) at least one change in direction, preferably several

Has changes in direction, and further preferably runs several times folded.

5. Laser system (10) according to claim 4, wherein the

Feed optics (20) is designed such that the beam path (38) runs in a plane that is perpendicular to a plane in which a

Beam path in the beam shape optics (28) runs.

6. Laser system (10) according to any one of the preceding claims, wherein the feed optics (20) is designed such that the first optical input channel (18a) and the second optical input channel (18b) for

Feeding of laser beams (14) with

different beam direction, in particular

opposite beam direction are formed.

7. Laser system (10) according to one of the preceding claims, wherein the feed optics (20) for at least one optical output channel (24a, 24b)

Path adjustment optics (42), wherein the

Path adjustment optics (42) is set up to set an optical path of at least one laser beam (14) in comparison to other laser beams (14)

Output channel (24a, 24b) to change.

8. Laser system according to one of the preceding claims, wherein more than two optical input channels (18a, 18b) are provided and / or wherein more than two

Input beam groups (16a, 16b) are provided, and the feed optics (20) are designed such that each of the output beam groups (26a, 26b) comprises at least one laser beam (14) from each of the input beam groups (16a, 16b).

9. Laser system (10) according to one of the preceding claims, wherein the beam shaping optics (28) comprises a shaping optics (32) which detects the laser beams (14) of the optical output channels (24a, 24b) and into one

Beam package with extended lines

Beam cross-section reshaped.

10. Laser system according to claim 9, wherein the beam shaping optics (28) additionally comprises a combination optics (35) which is set up to combine the laser beams (14) of an output beam group (26a, 26b)

Output channel (24a, 24b) or from

Output beam groups (26a, 26b) of several

Bring output channels (24a, 24b) in front of the shaping optics (32) into a combination beam, the shaping optics (32) being designed and arranged in such a way that it detects the combination beam.

11. Laser system (10) according to one of the preceding claims, wherein beam shaping optics (28) at least one

anamorphic telescope (30), which on one or more laser beams (14) of an optical output channel (24a, 24b) act.

12. Laser system (10) according to one of the preceding claims, wherein the different laser light sources (12a, 12b) feed into different optical input channels (18a, 18b).

13. Laser system (10) according to one of the preceding claims, wherein each laser light source (12a, 12b) for emitting at least two separate laser beams (14)

and at least two laser light sources (12a, 12b) in different optical input channels

(18a, 18b).