Hexagonal Packing Laser Ablation for Electro-Optic Substrates
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Solution Overview
Problem
Conventional laser ablation processes produce artifacts on the workpiece surface that result in undesirable diffraction patterns due to periodic arrangements of laser spots, which can be objectionable and affect the performance of electro-optic devices.
Innovation Solution
A hexagonal packing laser ablation process is employed, where laser spots are arranged in a hexagonal pattern with specific pulse spacing and pitch, and rows are laterally offset by half the pulse spacing, reducing overlap and minimizing diffraction effects by creating a surface profile with reduced peak-to-valley height and improved conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional laser ablation processes are used to remove coating layers, then coating removal efficiency is achieved, but undesirable diffraction patterns are produced due to periodic arrangements of laser spots
Solution Approach 1:
The patent applies asymmetry by using a hexagonal packing arrangement instead of a conventional periodic grid pattern. The laser spots are positioned at vertices of hexagons with specific radial distances and angular spacing, creating an asymmetric distribution that eliminates the periodicity causing diffraction patterns while maintaining efficient coating removal coverage
Solution Approach 2:
The patent transitions from a two-dimensional periodic grid arrangement to a three-dimensional hexagonal packing pattern that utilizes radial and angular dimensions. This dimensional change in the spatial distribution of laser spots disrupts the periodic arrangement that causes diffraction while maintaining systematic coverage for efficient ablation
2Productivity
If laser spots are arranged in periodic patterns for efficient coating removal, then processing speed is improved, but surface artifacts are created that affect device performance
Solution Approach 1:
The hexagonal packing arrangement with specific radial distances (first radial distance for primary vertices, second radial distance for secondary vertices) and angular spacing creates an asymmetric surface profile pattern. This asymmetric distribution eliminates periodic artifacts while maintaining the systematic coverage needed for fast processing speeds
Solution Approach 2:
The patent creates different local surface conditions by positioning laser spots at specific radial distances from the center. Primary vertices at one radial distance and secondary vertices at another create varied local ablation depths and surface profiles, preventing uniform periodic patterns that cause artifacts while maintaining overall processing efficiency
3Productivity
If laser spots are closely spaced to remove coating efficiently, then coating removal rate increases, but overlap between laser spots increases causing surface damage
Solution Approach 1:
The patent segments the laser spot distribution into primary vertices and secondary vertices of hexagons, with different radial distances from the center. This segmentation allows optimization of spacing to achieve sufficient overlap for complete coating removal while preventing excessive overlap that would cause surface damage
Solution Approach 2:
The hexagonal packing arrangement provides partial overlap between adjacent laser spots, which is sufficient to ensure complete coating removal without the excessive overlap that causes surface damage. The specific geometric distribution optimizes the overlap level to be just enough for effective ablation
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
The hexagonal packing laser ablation process reduces light diffraction, minimizes damage to the ablated surface, enhances conductivity, and facilitates efficient removal of the coating layer, resulting in improved performance and reduced processing times for electro-optic devices.
Implementation Method 1
A hexagonal packing laser ablation process is employed, where laser spots are arranged in a hexagonal pattern
Data Source
AI summary
A substrate has a first side and an opposing second side. The opposing second side has a first portion and a second portion. The substrate is at least partially transparent to visible light. A coating layer is disposed over the first portion but not the second portion of the opposing second side of the substrate. The second portion has an ablated surface including a hexagonal packed surface profile.