Laser Etching Sequence for Precise Transparent Workpiece Contours
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Solution Overview
Problem
Existing laser etching methods struggle to produce precise contours of different sizes in transparent materials due to the inability to selectively remove modified and unmodified material, leading to inflexible and material-thickness-dependent hole diameters and potential material loss.
Innovation Solution
A method involving multiple laser-induced modifications followed by etching operations with varying selectivities to selectively remove modified material and then unmodified material between, allowing for precise control over hole shapes and sizes without significant material loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single etching operation with high selectivity is used to remove predominantly modified material, then precise contours can be produced, but webs of unmodified material remain between the holes preventing complete separation
Solution Approach 1:
The etching process is segmented into multiple sequential operations with different selectivities. The first etching operation removes predominantly modified material with high precision, while subsequent etching operations remove the remaining webs of unmodified material. This segmentation allows each operation to be optimized for its specific function, achieving both precise contours and complete material separation.
2Ease of manufacture
If a single etching operation with low selectivity is used to remove both modified and unmodified material, then complete material removal is achieved, but material thickness is reduced and hole diameters become dependent on etching time
Solution Approach 1:
The etching process is divided into sequential operations with different selectivities. The first operation with high selectivity removes predominantly modified material while preserving unmodified material, maintaining material thickness and hole diameter control. Subsequent operations with lower selectivity remove the remaining webs without significantly affecting the already-formed holes, thus maintaining manufacturing precision while achieving complete material removal.
Solution Approach 2:
The high-selectivity etching operation is performed first to preliminarily form the holes with precise dimensions before the lower-selectivity operations remove the webs. This preliminary action ensures that the critical hole dimensions are established when the material is most resistant to etching, preventing unwanted diameter changes during subsequent web removal.
3Adaptability or versatility
If different laser modifications are introduced by changing laser parameters, then different selectivities can be achieved in subsequent etching, but the process complexity increases
Solution Approach 1:
Laser parameters such as pulse energy, pulse duration, and scanning speed are varied to create different types of material modifications with distinct etching selectivities. By carefully controlling these parameters, the process achieves versatile etching capabilities without requiring complex additional equipment, as the selectivity control is accomplished through parameter optimization within the existing laser system.
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 the production of complex structures with controlled dimensions and minimal material reduction by using laser-induced modifications and selective etching, ensuring precise control over hole shapes and sizes without excessive material loss.
Implementation Method 1
a material that is transparent to the laser radiation used is modified by means of one or more ultrashort laser pulses, at the focal point of which non-linearly induced absorption processes take place, for example multiphoton absorptions
Implementation Method 2
at the focal point of which non-linearly induced absorption processes take place, for example multiphoton absorptions or tunnel ionization
Implementation Method 3
The chemical and/or physical properties of the material are thereby modified in such a way that the material can be etched better. In a subsequent step, the modified material is then selectively removed by an etching process.
Data Source
AI summary
The present invention relates to a method for machining a workpiece, comprising the steps of introducing a plurality of adjacent modifications into the material of the workpiece by means of laser radiation, etching the material of the workpiece in a first etching operation with a first selectivity, in order to remove predominantly the material modified by the laser radiation, and, after completion of the first etching operation, etching the material of the workpiece in a second etching operation with a second selectivity, different from the first selectivity, in order to remove the webs left between the removed modified material.