METHOD AND DEVICE FOR LOCALLY DEFINED MACHINING ON THE SURFACES OF WORKPIECES USING LASER LIGHT

Abstract

The invention relates to a method and a device for locally defined machining on surfaces of workpieces. A laser beam (1) emitted by a laser radiation source (2) is aimed onto the reflecting surfaces of a plurality of adjacently arranged micromirrors that may be controlled individually with an electronic control and that are pivotable about at least one axis. Sub-beams (4) reflected by the reflecting surfaces of the micromirrors pivoted in a defined manner are incident and focused on the surface of a workpiece, which surface is arranged in the focal plane (6) of the focusing optics unit (5), at different adjustable positions, so that simultaneously a locally defined change in the workpiece material and/or a locally defined material removal with prespecifiable geometry is attained in a region of the workpiece near its surface. If a plurality of sub-beams (4) are incident together on the same position in the focal plane (6) of the focusing optics unit (5), these sub-beams (4) overlay one another in an incoherent manner.

Claims

1. A method for locally defined machining on the surfaces of workpieces using laser light, in which method a laser beam (1) emitted by a laser radiation source (2) is directed onto the reflecting surfaces of a plurality of adjacently arranged micromirrors that may be pivoted about at least one axis and that may be controlled with an electronic control, and from the reflecting surfaces of each micromirror pivoted in a defined manner, reflected sub-beams (4) are focused on a workpiece surface arranged in the focal plane (6) of a focusing optics unit (5) and are incident on different, adjustable positions, such that a locally defined change in the workpiece material and/or a locally defined removal of material, with predeterminable geometry, is simultaneously attained in a region of the workpiece close to its surface; wherein, if a plurality of sub-beams (4) together are incident on the same position in the focal plane (6) of the focusing optics unit (5), these sub-beams (4) overlay one another in an incoherent manner.

2. The method according to claim 1, characterized in that a spatial light modulator (SLM) (3) is used in which the micromirrors are arranged in a rows and columns arrangement.

3. The method according to claim 1, characterized in that the micromirrors and the workpiece are moved relative to one another.

4. The method according to claim 1, characterized in that the laser beam (1) is incident on the reflecting surfaces of all of the micromirrors and the sub-beams (4) that are reflected by all of the micromirrors are incident on the surface of the workpiece simultaneously with the locally defined laser machining.

5. The method according to claim 1, characterized in that the micromirrors are pivoted such that the sub-beams (4) that are strike one another in the focal plane (6) of the focusing optics unit (5) do not interfere with one another, but instead overlay one another in an incoherent manner.

6. The method according to claim 1, characterized in that the focusing optics unit (5) is arranged between the spatial light modulator (3) and the surface of the workpiece.

7. The method according to claim 1, characterized in that the focusing optics unit (5) is arranged between the laser radiation source (2) and the spatial light modulator (3).

8. The method according to claim 1, characterized in that individual lenses embodied as biconvex lenses, plan convex lenses, lenses of best shape or aspheres or microscope lenses, plan field lenses, or F-theta lenses, in a simple or telecentric design, are used as the focusing optics unit (5).

9. The method according to claim 1, characterized in that an ultra-short pulse laser, pulsed Nd:YAG laser, pulsed fiber laser, pulsed CO2 laser, CO2-TEA laser, or excimer laser is used for the laser radiation source (2).

10. The method according to claim 1, characterized in that at least one marking is created as a pattern with the locally defined laser machining.

11. The method according to claim 1, characterized in that, by using spatial light modulators (3), the wavefront of focused laser radiation is changed adaptively such that secondarily occurring wavefront changes are corrected, as a consequence of the influence on the optics unit, by the laser beam itself, which changes lead in particular to focal length changes.

12. A device for executing the method according claim 1, characterized in that a laser beam (1) emitted by a laser radiation source (1) is directed onto a plurality of adjacently arranged micromirrors that are pivotable about at least one axis, and sub-beams (4) reflected by micromirrors are incident focused on different positions of the surface; wherein a focusing optics unit (5) is arranged and embodied in the beam path such that the focused sub-beams (4) are incident on the workpiece surface arranged in the focal plane (6) and if a plurality of sub-beams (4) are incident on the same position together, these sub-beams (4) overlay one another in an incoherent manner.

Description

[0042] The invention shall be described in the following using an example.

[0043] FIG. 1 is a schematic illustration of an example of an arrangement that may be used when executing the inventive method. In the variant illustrated here, the focusing optics unit 5 is arranged between the SLM 3 and the image plane (focal plane of the focusing optics unit) 6.

[0044] A collimated laser beam 1 is directed onto a spatial light modulator (SIM) 3 by a laser radiation source 2. The SLM 3 represents a 2-dimensional arrangement of many micromirrors. In this example, the micromirrors are each pivotable, individually and independently, about two axes that are arranged perpendicular to one another.

[0045] The sub-beams 4 (of which only a few are depicted for the sake of simplicity) reflected by the individual reflecting surfaces of all of the micromirrors are incident on the focusing optics unit 5, which in this example is indicated by a simple focusing lens. The sub-beams 4 are directed onto the surface of a workpiece, indicated here with the focal plane of the focusing optics unit 6. The surface of the workpiece and the focal plane of the focusing optics unit 6 are arranged in the same plane.

[0046] Each individual micromirror is pivoted such that its sub-beam 4 is incident on a prespecified position. Sub-beams 4 that are reflected by the SLM 3 at the same angle and are incident on a common point in the image plane should overlay one another in an incoherent manner. All sub-beams 4 are incident, simultaneously locally defined, on the specific surface, so that a prespecified image of a specific geometry that is prespecifiable using an electronic control (not shown) is attained.

[0047] The laser radiation source 2 may be operated pulsed and, depending on the desired machining and taking into account the material of a workpiece or a coating embodied thereon, at a suitable power and wavelength.

[0048] FIG. 2 is a schematic illustration of an example of an arrangement that may be used when executing the inventive method. In the variant illustrated here, the focusing optics unit 5 is arranged between the laser radiation source 2 and the SLM 3.