Laser Material Processing with Overlapping Interaction Zones
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Solution Overview
Problem
Existing laser surgical methods for producing curved cut surfaces in materials, such as in ophthalmic operations, require precise localization of laser beams to avoid collateral damage and often rely on defined sequences of optical breakthroughs to prevent plasma bubble joining, which complicates the cutting process and increases the risk of incomplete cuts.
Innovation Solution
The solution involves controlling the distance between centers of interaction to be ≤10 μm and reducing pulse fluence to below 5 J/cm², allowing for overlapping zones of interaction to achieve material separation without forming large plasma bubbles, and dividing the cut surface into finer and coarser portions for improved visibility and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If defined sequences of optical breakthroughs are used to prevent plasma bubble joining, then cut quality is improved, but process complexity and risk of incomplete cuts increase
Solution Approach 1:
The patent changes the parameter of center-to-center distance to ≤10 μm and pulse fluence to below 5 J/cm², which fundamentally alters the interaction mechanism from sequential optical breakthroughs to overlapping nonlinear optical absorption zones, eliminating the need for complex defined sequences while maintaining cut quality
Solution Approach 2:
The patent merges adjacent zones of interaction by reducing the distance between centers to ≤10 μm, causing the zones to overlap and combine into a continuous modified region. This merging eliminates the need for defined sequences between discrete optical breakthroughs, simplifying the process while ensuring complete material separation
2Object-affected harmful factors
If precise localization of laser beams is used to avoid collateral damage, then tissue safety is improved, but equipment complexity and operational difficulty increase
Solution Approach 1:
The patent changes the fluence parameter to below 5 J/cm² and center distance to ≤10 μm, creating overlapping zones that confine the nonlinear optical absorption effect precisely to the intended path. This precise parameter control achieves localization without requiring complex beam positioning systems
Solution Approach 2:
The patent transitions from precise lateral beam positioning to precise control of the focus depth and zone overlap in the longitudinal dimension. By controlling the axial position and overlap of focal zones, the patent achieves three-dimensional confinement of the interaction volume, simplifying lateral positioning requirements
3Manufacturing precision
If higher pulse fluence is used to ensure optical breakthrough, then material separation is improved, but plasma bubble formation and hazards increase
Solution Approach 1:
The patent inverts the conventional approach by reducing fluence below 5 J/cm² and using overlapping zones instead of high-fluence optical breakthroughs. This parameter change eliminates plasma bubble formation while achieving material separation through cumulative nonlinear optical absorption in the overlapping regions
Solution Approach 2:
The patent applies partial action by using sub-threshold fluence levels that individually do not cause optical breakthrough or plasma formation, but collectively achieve complete material separation when multiple overlapping zones are applied. This partial action approach eliminates harmful plasma bubbles while maintaining effective cutting
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
This approach reduces the complexity of equipment, decreases personnel hazards, and enables the use of lower hazard class lasers, achieving high-quality cuts with reduced plasma bubble formation and increased precision, while allowing for smoother and more recognizable cut surfaces during surgical procedures.
Implementation Method 1
The laser pulse energy is usually selected such that an optical breakthrough in the tissue forms in the zone of interaction
Implementation Method 2
First, the optical breakthrough generates a plasma bubble in the material
Implementation Method 3
If a plasma is generated at a material interface which may even be located within a material structure, material removal is effected from said interface. This is then referred to as photoablation
Data Source
AI summary
A device for material processing by laser radiation, including a source of laser radiation emitting pulsed laser radiation for interaction with the material, optics focusing the pulsed processing laser radiation to a center of interaction in the material, and a scanning unit shifting the positions of the center of interaction within the material. Each processing laser pulse interacting with the material in a zone surrounding the center of interaction assigned to the laser pulse so that material is separated in the zones of interaction. A control unit controls the scanning unit and the source of laser radiation such that a cut surface is produced in the material by sequential arrangement of zones of interaction. The control unit controls the source of laser radiation and the scanning unit such that adjacent centers of interaction are located at a spatial distance a ≤10 μm from each other.