Laser Device Diffractive Optical Element Beam Pattern Matching
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Solution Overview
Problem
Adjusting and aligning the beam spot of a high-power laser for precise workpiece processing is challenging due to the invisible nature of the laser light, making setup and ongoing process monitoring difficult, especially when different wavelengths of the effective and pilot laser beams require distinct refraction and focusing behaviors.
Innovation Solution
A laser device with a diffractive optical element (DOE) that adjusts the beam patterns of both the effective and pilot laser beams to match in size and shape, using wavelength-dependent mirrors and beam expansion systems to ensure the pilot laser beam's cross-section is adapted to the effective laser beam's, allowing for precise control and monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pilot laser beam is introduced to enable visualization and monitoring of the beam spot, then the ease of operation and process monitoring are improved, but the device complexity increases due to the need to accommodate and synchronize multiple laser beams of different wavelengths
Solution Approach 1:
The patent introduces a pilot laser beam as an intermediary visible element that accompanies the invisible effective laser beam. The pilot beam serves as a mediator that enables visualization and monitoring without directly performing the processing task, thus solving the monitoring difficulty while maintaining system functionality
Solution Approach 2:
The pilot laser beam creates a visible copy or representation of the effective laser beam's path and focal spot. By generating a beam pattern that corresponds to the effective beam's intended trajectory, the system enables monitoring through this optical copy without interfering with the primary processing function
2Ease of operation
If the pilot laser beam is used to indicate the beam spot position, then the ease of operation is improved, but the manufacturing precision deteriorates because the beam spots of different wavelengths cannot be perfectly aligned
Solution Approach 1:
The patent employs beam expansion optics to change the spatial parameters of the pilot laser beam, specifically expanding it to match the size and shape of the effective laser beam's focal spot. This parameter adjustment compensates for the inherent wavelength-related focusing differences, enabling accurate visual alignment
Solution Approach 2:
The system uses dynamically adjustable beam expansion optics that can be tuned during operation to achieve optimal alignment between the pilot and effective beam spots. This dynamic adjustment capability allows the system to adapt to different wavelengths and focusing conditions, maintaining precision while enabling monitoring
3Manufacturing precision
If beam expansion optics are used to match the pilot laser beam size to the effective laser beam size, then the manufacturing precision is improved, but the device complexity increases due to additional optical components
Solution Approach 1:
The beam expansion optics serve multiple functions simultaneously: they expand the pilot beam to match the effective beam size, maintain the beam pattern correspondence, and enable adjustable alignment. This multi-functionality reduces the need for separate adjustment mechanisms, thereby limiting the increase in device complexity while achieving precise beam pattern matching
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise control and alignment of beam patterns on workpieces, facilitating optimal processing and monitoring by ensuring the pilot laser beam's pattern matches the effective laser beam's, thus improving the accuracy and efficiency of laser processing tasks.
Implementation Method 1
laser optics (4), which has at least one diffractive optical element (DOE) (7) to determine a shape of the beam pattern
Implementation Method 2
the laser beams of the effective power laser and the pilot target laser by means of laser optics
Implementation Method 3
using wavelength-dependent mirrors and beam expansion systems
Implementation Method 4
the beam cross section of the pilot laser beam is enlarged and in particular adapted to that of the effective laser beam on the workpieces
Data Source
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AI summary
The invention relates to a device (1) and a method for processing and/or joining workpieces (5, 5') using laser radiation, comprising a power laser and a pilot laser which emit laser beams (2, 3) of different wavelengths, wherein the laser beams (2, 3) are directed onto the workpieces (5, 5') via a laser optic (4). The laser optic (4), which includes at least one diffractive optical element (DOE, 7) as a masking system, adapts the beam pattern (6') of the pilot laser to the beam pattern (6) of the power laser in the laser beams (2, 3). This is preferably done by coupling the pilot laser beam (3) out of the active laser beam (2) for a partial path length using dichroic mirrors (8,9) and by widening the diverging pilot laser beam (3) on the coupled partial path length using deflecting mirrors (10,11) whose distance to the dichroic mirrors (8,9) can be changed.