WO2005063433A1

WO2005063433A1 - Laser apparatus, particularly for welding or machining a workpiece

Info

Publication number: WO2005063433A1
Application number: PCT/EP2004/013740
Authority: WO
Inventors: Vitalij Lissotschenko; Aleksei Mikhailov
Original assignee: Hentze-Lissotschenko Patentverwaltungs Gmbh & Co. Kg
Priority date: 2003-12-20
Filing date: 2004-12-03
Publication date: 2005-07-14

Abstract

Disclosed is a laser apparatus, particularly for welding or machining a workpiece, comprising a plurality of laser units (1), each of which is provided with at least one semiconductor laser element (2), the laser light (4a to 4h, 8a to 8h) of the at least one semiconductor laser element (2) emerging from the laser unit (1), and beam-combining means (5, 14) that combine the laser light (4a to 4h, 8a to 8h) radiating from the individual laser units (1) into laser light (7, 7') jointly emerging from the beam-combining means (5, 14). At least one, preferably each, laser unit (1) is provided with optical means (3) which ensure that the laser light (4a to 4h, 8a to 8h) emerging from the laser unit (1) is at least partly collimated while at least one, preferably each, laser unit (1) represents a unit that can be replaced as a whole.

Description

"Laser device, especially for welding or machining a workpiece"

The present invention relates to a laser device, in particular 5 for welding or machining a workpiece, comprising a plurality of laser units, each comprising at least one semiconductor laser element, the laser light of the at least one semiconductor laser element being able to emerge from the laser unit, and beam combining means which be able to combine the .0 individual laser units outgoing laser light into laser light emerging from the beam combining means.

Laser devices of the type mentioned at the outset are known and, according to the prior art, have so-called stacks of laser diode bars as semiconductor laser elements. In laser devices of the aforementioned type, the light emanating from the individual stacks is combined in beam combining means, which can be designed, for example, as polarization couplers or wavelength couplers: 0 and focused with appropriate optics either directly on a workpiece to be machined or first introduced into an optical fiber ,

It proves to be disadvantageous in the case of laser devices of the type mentioned at the outset: 5 that if a stack serving as a semiconductor laser element fails, a new stack which replaces the failed stack can only be reintroduced into the laser device with a particularly high adjustment effort. The reason for this is that the laser light emanating from the stacks or the laser units essentially formed by them must be shaped or collimated by optics arranged in the vicinity of the stacks, depending on Positioning the newly introduced stack in the laser device, the entire optical adjustment of the laser light emanating from the laser units can under certain circumstances be very time-consuming.

The problem on which the present invention is based is the creation of a laser device of the type mentioned at the outset, in which a failed semiconductor laser element can be replaced with less effort.

This is achieved according to the invention in that at least one, preferably each, of the laser units comprises optical means which ensure that the laser light emerging from the laser unit is at least partially collimated, at least one, preferably each, of the laser units representing a unit which can be exchanged as a whole. The at least partially collimating laser light emanating from the semiconductor laser element is thus integrated into the laser units, these laser units as a whole being interchangeable. This eliminates the adjustment effort when replacing a defective one

Semiconductor laser element minimized. The reason for this is that the entire laser unit, which in addition to the semiconductor laser element also includes appropriate optical means, can be replaced. The particularly complex adjustments of so-called FAC lenses for the collimation of the fast axis and so-called SAC

Lenses for the collimation of the slow axis can thus be preset in the laser unit at the factory, so that the adjustment effort when replacing a semiconductor laser element can be comparatively small.

According to claim 2, it can preferably be provided that the laser device comprises positioning means that are reproducible Allow positioning of at least one, preferably one of each of the laser units in the laser device. By means of such positioning means, the position of an exchanged laser unit with respect to the other laser units or with respect to the beam combining means will essentially correspond to the position which the defective and meanwhile removed laser unit has assumed. The reproducible positioning thus minimizes the adjustment effort when replacing a laser unit.

According to claim 3, it can in particular be provided that the positioning means enable the at least one laser unit to be positioned in two, in particular three, spatial directions perpendicular to one another. According to claim 4, it can further be provided that the positioning means enable the at least one laser unit to be positioned in two, in particular three mutually independent adjustment angles. The laser unit can thus be positioned as completely as possible in a three-dimensional environment by the positioning means.

According to claim 5 it can in particular be provided that the

Positioning means enable the positioning of the at least one laser unit with an accuracy of 1 μm or better. Such an accuracy is completely sufficient for a laser device used, for example, for laser welding. The positioning means can thus enable the exchange of a laser unit with the semiconductor laser element provided therein without additional optical adjustment of the installed laser unit.

According to claim 6 it can be provided that the positioning means comprise pins and / or projections as well as recesses cooperating with them. Such positioning means are, on the one hand, simple in terms of production technology produce and can also enable positioning with the aforementioned high accuracy.

According to claim 7, it can in particular be provided that the laser device comprises a plate on which the laser units and the beam combining means are arranged.

Alternatively or additionally, it can be provided according to claim 8 that the laser device comprises a cuboid or the like, on the surfaces of which the laser units and the

Beam combining means are arranged.

Pins and / or projections and / or recesses which cooperate with them can be provided on the plate or cuboid or the like and on the laser units and / or the beam combining means.

According to claim 1 0 can be provided in particular that the plate or the cuboid are cooled, in particular water-cooled. The plate or cuboid can not only be used as the basis for the

Serve positioning of the laser units, but also effect the cooling of the laser units.

According to claim 1 1 can be provided in particular that the semiconductor laser element is a laser diode bar. Such one

Laser diode bars is a significantly smaller and less complicated unit than the interchangeable stacks of laser diode bars known from the prior art. By combining a laser diode bar with appropriate optical means for collimating the light emanating from the laser diode bar, a compact laser unit is created which is simple to replace and, in particular, is also considerably less expensive than a stack of Laser diode bars. If one of the laser diode bars in the stack fails in a stack of laser diode bars, the entire extremely expensive stack must be replaced. In the laser device according to the invention, it is only necessary to replace a comparatively inexpensive, compact laser unit, which contains a laser diode bar as the semiconductor laser element.

According to claim 12, it can in particular be provided that the laser device is designed in such a way that at least one, in particular each, of the laser units can be replaced during operation of the laser device. In this way, the smooth operation of the laser device according to the invention is ensured. In the case of the laser devices known from the prior art, this was due in particular to the difficult ones

Readjustment of the laser light coming from the stacks is not possible.

According to claim 13, it can be provided in particular that the beam combining means comprise a plurality of mirrors for combining the laser light emanating from a plurality of laser units, in particular the laser light emanating from one of the laser units can be reflected on one of the mirrors, whereas the laser light emanating from another laser unit can walk past this mirror. In this way, the laser light emanating from two or more laser units can be combined with simple means.

According to claim 14, it can be provided in particular that the beam combining means comprise at least one polarization coupler which can combine laser light of different polarization. Alternatively or additionally, it can be provided according to claim 15 that the beam combining means comprise at least one wavelength coupler that can combine laser light of different wavelengths. By means of these wavelength couplers known from the prior art, that from the

Laser device emerging laser light consist of portions of different wavelengths. This may be an advantage. In particular, customer-specific requirements with regard to different wavelengths can also be met here.

According to claim 16 it can be provided that at least one, preferably each, of the laser units is designed as a module, in particular as an encapsulated module, preferably as a module filled with nitrogen or the like. The design of a laser unit as an encapsulated module makes the laser unit comparatively insensitive to environmental influences, so that in particular the factory pre-adjustment of the optical means is not impaired. In this way, the laser device can be operated comparatively trouble-free. This insensitivity of the laser unit is further increased by filling this encapsulated module with nitrogen or other comparatively neutral gases.

According to claim 1 7 can in particular be provided that the

Laser device control means which can control the output power of the laser device.

It can be provided according to claim 18 that the control means can change the supply current and / or the supply voltage of the other laser units in the event of failure of a laser unit in such a way that the total output of the Laser device emerging laser light remains substantially the same. In this way, the smooth operation of the laser device is ensured.

As an alternative or in addition, it can be provided that the laser device comprises at least one laser unit serving as a reserve, the control means being able to operate the at least one laser unit serving as a reserve in the event of a laser unit failure, so that the total output of the laser device exiting the laser device Laser light in

Remains essentially the same. This measure can also ensure the smooth operation of the laser device according to the invention.

According to claim 20 it can in particular be provided that the

Optical means of the at least one, preferably each of the laser units comprise a FAC lens and / or a SAC lens, preferably additionally additional lenses for homogenization and / or beam transformation. By means of such optical means, the laser light emerging from the laser unit can meet high demands and can be easily combined with the laser light emerging from other laser units by means of the beam combining means, or the combined laser light can be focused comparatively easily on an area of application on the workpiece. Further features and advantages of the present invention will become clear from the following description of preferred exemplary embodiments with reference to the accompanying figures. Show in it

Figure 1 is a schematic plan view of a section of a laser device according to the invention.

2 shows a schematic top view of a further embodiment of a laser device according to the invention;

3 shows a schematic plan view of a section of a further embodiment of a laser device according to the invention;

4 is a view according to arrows IV-IV in FIG. 3rd

The from Fig. 1 visible laser device according to the invention comprises a plurality of laser units 1, each of which comprises a semiconductor laser element 2 and optical means 3 in the illustrated embodiment. The semiconductor laser element 2 can in particular be designed as a laser diode bar. The optical means 3 are only shown schematically by a lens. The optical means 3 can in particular one FAC lens, several SAC

Lenses and other beam shaping means include. The FAC lens is used for at least partial collimation of the laser light emanating from the laser diode bar 2 in the so-called fast-axis direction, whereas the SAC lenses are used for at least partial collimation of the light emitting from the laser diode bar

Serve laser light in the perpendicular, so-called slow axis. The other beam shaping means of the laser units 1 can for example, homogenizers or lens combinations for combining the individual partial beams of the light emanating from the semiconductor laser element.

Each of the laser units 1 can thus be designed such that a comparatively well-collimated, in particular homogeneous and well-focussable laser beam 4a to 4h emerges from them. In particular, the laser units 1 can have a modular design and can be encapsulated, for example, so that the interior of the laser units 1 is not exposed to any or only very few environmental influences.

In particular, these encapsulated laser units 1 could also be filled with nitrogen or similar neutral gases.

The laser device shown in FIG. 1 further comprises beam combining means 5, by means of which the individual

Laser units 1 emerging laser beams 4a to 4h can be combined. For this purpose, the beam combining means 5 comprise a plurality of mirrors 6, each of which can combine a plurality of laser beams 4a to 4h in such a way that the combined laser light 7 of the individual laser units 1 can emerge from the beam combining means 5.

3 shows a further embodiment of a device according to the invention, which illustrates the combination of individual laser beams 8a to 8h by mirrors 9a to 9h. It can be seen in particular that the laser beam 8a emanating from a first laser unit 1 on the mirror 9a downwards in FIG. 3 is reflected. The laser beam 8b emanating from a second laser unit 1 is reflected downward in FIG. 3 by a second mirror 9b, the laser beam 8a emanating from the mirror 9a passing over this second mirror 9b (see FIG. 4 in this regard). The laser beam 8c emanating from a third laser unit 1 becomes 3 reflected downward from a third mirror 9c, the laser beams 8a and 8b reflected by the two mirrors 9a and 9b passing over this mirror 9c. From Fig. 4 it can be seen that the remaining mirrors 9d to 9h are designed accordingly and have an ever smaller height in the direction from left to right in Fig. 4 or from bottom to top in Fig. 3, so that more and more Laser beams 8a to 8g can run across the mirrors 9d to 9h.

In this way it is achieved that a bundle of laser beams 8a arranged one above the other can emerge downward from FIG. 3 and can be focused on a common focus area, for example, by further optical means such as the lens 10 shown as an example.

1 also shows an optical unit 11 with a schematically illustrated optical element 12 and, by way of example, a fiber coupling 13. Within the optics unit 1 1 there is also a beam combining means 14, which can be designed, for example, as a so-called polarization coupler. Here, the laser light 7 emerging from the beam combining means 5 is used, for example, from similar ones

Beam combining means emerging laser light 7 'united. For this purpose, the laser light 7 must have a different polarization than the laser light 7 ', in particular the polarization vectors of the

Laser light 7, 7 'are perpendicular to each other. Such polarization couplers are well known from the prior art and are not described in detail here.

Alternatively, there is the possibility that the beam combining means

1 4 is designed as a so-called wavelength coupler. For this purpose, the laser light 7 and the laser light 7 'would have to be different Have a wavelength so that, for example, dielectric mirrors or the like can combine the laser light 7 with the laser light 7 '. Such wavelength couplers are also well known from the prior art and are not described in detail here.

Within the optical unit 11, the laser light 7, 7 ′ combined in this way can be shaped further, for example, by means of the schematically illustrated optical element 12. In particular, partial beams arranged one above the other can be combined using means known from the prior art. In this way, the laser light can be coupled into an optical fiber by the fiber coupling 13 shown below. Alternatively, the laser light emerging from the optical unit 11 can also be used directly for material processing or

Welding can be used. For this purpose, for example, the optical unit can comprise corresponding focusing means, which can generate a focus area suitable for welding.

2 shows a laser device in which the same parts are provided with the same reference numerals as in FIG. 1. In particular, a plurality of laser units 1 are also provided here. Furthermore, four beam combining means 5 are shown, which are designed, for example, like the beam combining means 5 in FIG. 1. The laser beams emanating from these beam combining means 5 can be successively combined in further beam combining means 14. For example, the beam combination means 14 on the left in FIG. 2 and the right in FIG. 2 can be designed as a polarization coupler and the beam combination means 14 in the middle in FIG. 2 as

Wavelength coupler can be executed. Also in Fig. 2, an optical unit 11 and a fiber coupling 13 are shown, the combined laser light being coupled into an optical fiber 15 by the fiber coupling 13.

The laser units 1 shown in FIGS. 1 to 3 can in particular all be arranged on a plate. Alternatively, the laser units could also be arranged on the surfaces of a cuboid in three spatial directions with respect to one another. In particular include the laser devices shown

Positioning means that enable reproducible positioning of each of the laser units 1 on the plate or on the cuboid. For example, these positioning means can comprise pins and associated recesses or projections and associated recesses. For example, the pins can be arranged on the plate or the square r and the recesses in the laser units 1 or vice versa. In particular, positioning accuracies of 1 μm or better can be achieved using these positioning means. There is also the possibility that the positioning means enable the laser units to be positioned in three mutually independent spatial directions and three mutually independent angular positions, such as, for example, a pitch angle, a swivel angle and an angle of rotation.

There is still the possibility that the plate and / or the

Cuboids are water-cooled, in particular are traversed by a whole system of water pipes.

There is also the possibility that the laser light originating from individual laser units 1 has a different wavelength than the laser light originating from other laser units 1. Overall, in the invention Laser device by four or more different laser wavelengths are combined together.

The laser device according to the invention can further comprise control means designed as control electronics, which can increase, for example, the supply voltage and / or the supply current of the other laser units if one of the laser units fails, so that the output power of the entire laser device remains essentially the same. As an alternative or in addition to this, laser units serving as a reserve could also be present in the laser device and are put into operation in the event of failure of one or more of the laser units 1.

Furthermore, in the laser device according to the invention, the replacement of a single laser unit 1 during the operation of the

Laser device may be possible. For this purpose, safety means could be provided, for example, which prevent light from escaping at a different location than the one provided for when the laser device is in operation. For example, when replacing a laser unit 1, windows could be closed to prevent taillights or the like. In particular, the individual laser units can be operated with a comparatively small supply voltage of, for example, 2V, so that due to this low supply voltage, manual replacement of an individual laser unit is not associated with any dangers for the user. LIST OF REFERENCE NUMERALS Laser unit semiconductor laser element opticsa - 4h of 1 outgoing laser light beam combination means mirror, 7 'out of 5 outgoing laser lightta - 8h outgoing laser lightta - 9h laser light outgoing - 9h mirror0 lens1 optics unit2 optical element in 1 13 fiber coupling4 beam combining means5 optical fiber

Claims

claims:

1 . Laser device, in particular for welding or machining a workpiece, comprising - a plurality of laser units (1), each comprising at least one semiconductor laser element (2), the laser light (4a to 4h, 8a to 8h) of the at least one semiconductor laser element (2 ) can emerge from the laser unit (1); - Beam combining means (5, 14) which can combine the laser light (4a to 4h, 8a to 8h) emanating from the individual laser units (1) into laser light (7, 7 ') emerging from the beam combining means (5, 14); characterized in that at least one, preferably each, of the laser units (1) comprises optical means (3) which ensure that the laser light (4a to 4h, 8a to 8h) emerging from the laser unit (1) is at least partially collimated, at least one, preferably each, of the laser units (1) represents a unit which can be exchanged as a whole.

2. Laser device according to claim 1, characterized in that the laser device comprises positioning means which enable reproducible positioning of at least one, preferably one of each of the laser units (1) in the laser device.

3. Laser device according to claim 2, characterized in that the positioning means positioning the at least enable a laser unit (1) in two, in particular three mutually perpendicular spatial directions.

4. Laser device according to one of claims 2 or 3, characterized in that the positioning means allow the positioning of the at least one laser unit (1) in two, in particular three mutually independent adjustment angles.

5. Laser device according to one of claims 2 to 4, characterized in that the positioning means enable the positioning of the at least one laser unit (1) with an accuracy of 1 μm or better.

6. Laser device according to one of claims 2 to 5, characterized in that the positioning means comprise pins and / or projections and recesses which interact with them.

7. Laser device according to one of claims 1 to 6, characterized in that the laser device comprises a plate on which the laser units (1) and the beam combining means (5, 14) are arranged.

8. Laser device according to one of claims 1 to 7, characterized in that the laser device comprises a cuboid or the like, on the surfaces of which the laser units (1) and the beam combining means (5, 14) are arranged.

9. Laser device according to one of claims 7 or 8, characterized in that in each case pins and / or projections and / or recesses cooperating with them on the plate or cuboid and on the laser units (1) and / or the beam combining means (5, 14 ) are arranged.

1 0. Laser device according to one of claims 7 to 9, characterized in that the plate or the cuboid is cooled, in particular water-cooled.

1 1. Laser device according to one of claims 1 to 10, characterized in that the semiconductor laser element (2) is a laser diode bar.

12. Laser device according to one of claims 1 to 1 1, characterized in that the laser device is designed such that at least one, in particular each of the laser units (1) is interchangeable during operation of the laser device.

1 3. Laser device according to one of claims 1 to 12, characterized in that the beam combining means (5) a plurality of mirrors (6, 9a to 9h) for combining the laser light emanating from a plurality of laser units (1) (4a to 4h, 8a to 8h), in particular the laser light (4a to 4h, 8a to 8h) emanating from one of the laser units (1) can be reflected on one of the mirrors (6, 9a to 9h), whereas that emanating from another laser unit (1) Laser light (4a to 4h, 8a to 8h) can pass this mirror (6, 9a to 9h).

14. Laser device according to one of claims 1 to 13, characterized in that the beam combining means (14) comprise at least one polarization coupler which can combine laser light of different polarization.

1 5. Laser device according to one of claims 1 to 14, characterized in that the beam combining means (14) comprise at least one wavelength coupler, which can combine laser light of different wavelengths.

16. Laser device according to one of claims 1 to 15, characterized in that at least one, preferably each, of the laser units (1) is designed as a module, in particular as an encapsulated module, preferably as a module filled with nitrogen or the like.

1 7. Laser device according to one of claims 1 to 16, characterized in that the laser device comprise control means which can control the output power of the laser device.

18. Laser device according to claim 17, characterized in that the control means in the event of failure of a laser unit (1) can change the supply current and / or the supply voltage of the other laser units (1) such that the total power of the laser light emerging from the laser device (1) in Remains essentially the same.

19. Laser device according to one of claims 1 7 or 18, characterized in that the laser device comprises at least one laser unit (1) serving as a reserve, the control means in the event of failure of a laser unit (1) in the at least one laser unit (1) serving as a reserve Can operate, so that the total power of the laser light emerging from the laser device remains essentially the same.

20. Laser device according to one of claims 1 to 19, characterized in that the optical means (3) of the at least one, preferably each of the laser units (1) a FAC lens and / or a SAC lens, and preferably further lenses for homogenization and / or beam transformation.