Laser processing head
A variable focal length collimator in scanner laser processing heads addresses the challenge of signal fluctuations by dynamically adjusting focus and collimation, improving signal quality and reducing mechanical complexity.
Patent Information
- Application Number
- DE102023116103
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-06-20
- Publication Date
- 2025-07-31
- Estimated Expiration
- 2043-06-20
AI Technical Summary
Scanner laser processing heads with prefocus systems face challenges in adapting the collimation and focus position of process light due to varying image plane spacing across different scanning field positions, leading to signal fluctuations and requiring mechanical adjustments that are slow, costly, and space-consuming.
Employ a variable focal length process light collimator, such as a deformable lens, to dynamically adjust the focal length based on scan field positions, ensuring consistent signal quality across the scanning field.
The solution provides quick, automatic, and compact adaptation of process light focus and collimation, enhancing signal quality and reducing fluctuations in scanner laser processing heads, particularly prefocus systems.
Smart Images
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Abstract
Claims
[1] Laser processing head (1) for processing a workpiece (3) by means of a laser processing beam (4), comprising: a scanning device (20) for directing the laser processing beam (4) to a plurality of positions on the workpiece (3); a processing beam optics (10) for adjusting a focus position of the laser processing beam (4) and for focusing the laser processing beam (4), wherein the processing beam optics (10) is arranged between an entrance port (11) for the laser processing beam (4) and the scanning device (20); a sensor arrangement (50) for detecting process light (5) with at least one sensor (55); a coupling-out optics (30) for coupling out process light (5) to the sensor arrangement (50), wherein the coupling-out optics (30) is arranged between the processing beam optics (10) and the scanning device (20); and a process light optics (40) for adjusting a focus position of the process light (5) with respect to the sensor (55), wherein the process light optics (40) is arranged between the coupling-out optics (30) and the sensor arrangement (50) and comprises a variable lens (45) with an adjustable focal length, wherein the laser processing head (1) further comprises a controller (80) which is configured: • to control the processing beam optics (10) for adjusting the focus position of the laser processing beam (4) according to a control default value for the focus position of the laser processing beam (4) and to adjust the focal length of the variable lens (45) based on the control default value for the focus position of the laser processing beam (4) and / or • to adjust the focal length of the variable lens (45) and to control the variable lens (45) to adjust its focal length in proportion to controlling the processing beam optics (10) to adjust the focus position of the laser processing beam (4). [2] Laser processing head (1) according to claim 1, wherein the variable lens (45) is a deformable lens whose focal length is adjustable depending on the deformation; and / or wherein the variable lens (45) is a liquid lens; and / or wherein the focal length of the variable lens (45) is adjustable within a focal length range of 1000 ± 500 mm or 800 ± 100 mm. [3] Laser processing head according to one of the preceding claims, wherein the coupling-out optics (30) are configured to coaxially couple a beam path of the sensor arrangement (50) with a beam path of the laser processing beam (4). [4] Laser processing head according to one of the preceding claims, wherein a common beam path of the laser processing beam (4) and the sensor arrangement (50) is arranged in a region of the focused laser processing beam (4). [5] Laser processing head according to one of the preceding claims, wherein the processing beam optics (10) are pre-focusing optics of the laser processing beam (4); and / or wherein all optical elements for focusing the laser processing beam (4) are arranged outside the beam path of the sensor arrangement (50) or between the output optics (30) and the entrance port (11). [6] Laser processing head according to one of the preceding claims, wherein no focusing optics and / or no lens are arranged in a common beam path of the laser processing beam (4) and the sensor arrangement (50); and / or wherein all lenses of the laser processing head (1) are arranged outside a common beam path of the laser processing beam (4) and the sensor arrangement (50). [7] Laser processing head according to one of the preceding claims, wherein the processing beam optics (10) comprises a first optics (15) for adjusting the focus position of the laser processing beam (4), wherein the first optics (15) comprises a lens with an adjustable focal length or a lens which is arranged axially displaceably in the beam path of the laser processing beam. [8] Laser processing head according to claim 7, wherein the processing beam optics (10) comprises a second optics (18), and wherein one of the first and second optics (15, 18) serves to collimate the laser processing beam (4) and the other of the first and second optics (15, 18) serves to focus the laser processing beam (4). [9] Laser processing head according to one of the preceding claims, wherein the process light optics (40) comprises the variable lens (45) for collimating the process light (5) and a focusing optics (48) for focusing the process light (5). [10] Laser processing head according to one of the preceding claims, wherein the sensor arrangement (50) comprises at least one of the following sensors (55): a photodiode, a photodiode array, a camera, a spectrometer, a multi-spectral sensor, a sensor for detecting an intensity of the process light, an optical sensor for infrared radiation, an optical sensor for UV radiation, and a sensor for visible light. [11] Laser processing head (1) according to one of the preceding claims, further comprising a controller (80) which is arranged: to adjust the focal length of the variable lens (45); and / or to control the scanning device (20) according to a control default value for a scan field position; and / or to control the processing beam optics (10) for adjusting the focus position of the laser processing beam (4) according to a control default value for the focus position of the laser processing beam (4). [12] Laser processing head (1) according to claim 11, wherein the controller (80) is arranged to adjust the focal length of the variable lens (45) based on the control default value for a scan field position. [13] Laser processing head (1) according to claim 11 or 12, wherein the controller (80) is arranged to carry out a control of the variable lens (45) for adjusting its focal length synchronously with and / or proportionally to a control of the scanning device (4). [14] Laser processing head (1) according to one of claims 11 to 13, wherein the controller (80) is configured to adjust the focal length of the variable lens (45) based on a measured value of an optical path length to a current position of the laser processing beam (4) on the workpiece (3), wherein the laser processing head comprises an optical measuring device for measuring the optical path length. [15] Laser processing head (1) according to one of claims 11 to 14, wherein the sensor arrangement (50) comprises a photodiode as a sensor (55) and the controller (80) is configured to adjust the focal length of the variable lens (45) as a function of a scan field position such that a targeted defocusing of the process light (5) on the sensor (55) occurs in order to avoid saturation of the photodiode.
Citation Information
Patent Citations
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DE102021101658A1
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EP3532238B1