Apparatus and method for forming a laser beam

Patent metadata

Field	Value
Publication number	US-12059746-B2
Application number	US-202117387168-A
Country	US
Kind code	B2
Filing date	Jul 28, 2021
Priority date	Jan 31, 2019
Publication date	Aug 13, 2024
Grant date	Aug 13, 2024

Abstract

An apparatus for forming a laser beam can include a controllable spatial light modulator, a control device for controlling the light modulator, and a beam guiding optical unit, wherein the control device is configured to split a display plane of the light modulator into a plurality of display regions and to represent a first beam influencing structure in at least one first display region of the plurality of display regions and a second beam influencing structure in a second display region of the plurality of display regions, wherein the beam guiding optical unit is configured to cause the laser beam to interact along the direction of propagation thereof firstly with the first display region and then with the second display region.

First claim

What is claimed is:

1. An laser beam forming apparatus, comprising:
a controllable spatial light modulator;
a control device for controlling the light modulator; and
a beam guiding optical unit; wherein,
the control device is configured to split a display plane of the light modulator into a plurality of display regions and to represent a first beam influencing structure in at least one first display region of the plurality of display regions and a second beam influencing structure in a second display region of the plurality of display regions;
the beam guiding optical unit is configured to cause the laser beam to interact with the first display region and then with the second display region; and
a beam forming optical unit configured to change a polarization of the laser beam between the first display region and the second display region.

2. The apparatus of claim 1 , wherein the beam guiding optical unit has at least one mirror arranged downstream from the first display region to direct the laser beam to the second display region.

3. The apparatus of claim 1 , further comprising a diagnosis device configured to determine at least one property of a test beam from at least one display region of the plurality of display regions.

4. The apparatus of claim 3 , wherein the diagnosis device is operatively connected to the control device to control the light modulator depending on the at least one determined property of the test beam.

5. The apparatus of claim 3 , further comprising an output coupling optical unit configured to direct the test beam from the at least one display region of the plurality of display regions onto the diagnosis device.

6. The apparatus of claim 1 , wherein the beam forming optical unit comprises a polarization separating device configured to separate differently polarized beam portions of the laser beam coming from the second display region at least partly from one another.

7. The apparatus of claim 1 , wherein the beam forming optical unit is configured to be switchable between a first, switched-off functional state and a second, switched-on functional state by virtue of at least one optical element of the beam forming optical unit being:
displaceable spatially into a beam path of the laser beam and out of the beam path; or
switchable between two switching states in the beam path of the laser beam.

8. The apparatus of claim 1 , further comprising a processing optical unit configured to guide the laser beam coming from the light modulator onto a workpiece.

9. The apparatus of claim 3 , wherein the diagnosis device is configured to calibrate the light modulator by the control of the light modulator being tuned over a control interval further comprising
detecting, using a recording device, for at least two control regions of the light modulator an intensity of the test beam assigned to the respective control region;
comparing the respective intensities with one another; and,
correcting the control for the at least two control regions on the basis of the compared intensities.

10. The apparatus of claim 9 , further comprising:
changing, depending on the control of the light modulator, a polarization state of the test beam;
determining a phase shift between intensity profiles of the at least two control regions that are detected depending on the control; and,
applying the correction dependent on the phase shift.

11. The apparatus of claim 9 , wherein the diagnosis device is configured to determine the correction of the control for a plurality of control regions depending on a beam parameter or a beam effect of the test beam on the light modulator.

12. A method of forming a laser beam, the method comprising:
interacting, by the laser beam, with a first display region of a controllable spatial light modulator;
interacting, by the laser beam, with a second display region of the controllable spatial light modulator;
generating a first beam influencing structure in the first display region; and
generating a second beam influencing structure in the second display region by control of the light modulator; the method comprising
generating, in a first functional state, a phase influencing structure, as beam influencing structure both in the first display region and in the second display region; wherein,
influencing, by phase influencing structure, in the first display region a first amplitude distribution of the laser beam after a first propagation distance and the phase influencing structure in the second display region; and,
increasing uniformity of a phase distribution in a cross-sectional plane of the laser beam; or
influencing a second amplitude distribution after a second propagation distance.

13. The method of claim 12 , further comprising:
generating, in a second functional state, a phase influencing structure as first beam influencing structure in the first display region; and
influencing an amplitude distribution of the laser beam, wherein a polarization of the laser beam is changed between the first display region and the second display region; and
generating, in the second display region, a second beam influencing structure, the second beam influencing structure comprising a polarization influencing structure; and
influencing, by the second beam influencing structure, the polarization of the laser beam, wherein beam portions of the laser beam with specific polarization are filtered downstream of the second display region.

14. The method of claim 13 , further comprising switching between the first functional state and the second functional state.

15. The method of claim 12 , further comprising:
interacting, by the laser beam downstream of the second display region, with a third display region of the controllable spatial light modulator;
generating a third beam influencing structure, in the third display region by control of the light modulator;
generating a phase influencing structure as beam influencing structure both in a first display region and in a second display region; wherein,
influencing, by the phase influencing structure in the first display region, a first amplitude distribution of the laser beam after a first propagation distance and the phase influencing structure in the second display region;
increasing uniformity of a phase distribution in a cross-sectional plane of the laser beam; or
influencing a second amplitude distribution after a second propagation distance;
changing, a polarization of the laser beam between the second display region and the third display region;
generating a polarization influencing structure as a third beam influencing structure in the third display region;
influencing locally, by the third beam influencing structure, the polarization of the laser beam; and,
filtering beam portions of the laser beam with specific polarization downstream of the third display region.

16. The method of claim 12 further comprising:
determining a property of a test beam coming from at least one observed display region of a plurality of display regions; wherein,
the beam influencing structure of the at least one observed display region is changed depending on the at least one determined property.

17. The method of claim 12 , wherein a workpiece is irradiated with the laser beam downstream of the light modulator.

18. An laser beam forming apparatus, comprising:
a controllable spatial light modulator;
a control device for controlling the light modulator; and
a beam guiding optical unit; wherein,
the control device is configured to split a display plane of the lig

Assignees

• Trumpf Laser Gmbh

Inventors

• Kumkar Malte
• Grossmann Daniel
• Flamm Daniel
• Pang Hao

Classifications

• G02B27/0905

  Dividing and/or superposing multiple light beams · CPC title

• B23K26/0643 Primary

  comprising mirrors · CPC title

• B23K26/702

  Auxiliary equipment · CPC title

• B23K26/03

  Observing, e.g. monitoring, the workpiece · CPC title

• B23K26/062

  by direct control of the laser beam · CPC title