Interleaved Laser Ablation for Low-Diffraction Transparent Surfaces
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Solution Overview
Problem
Laser ablation processes often produce artifacts on the workpiece surface that result in undesirable diffraction patterns due to periodic arrangements of laser spots, leading to diffraction severity issues that can affect the quality of the ablated surface, particularly in applications like electrochromic devices where optical clarity and conductivity are crucial.
Innovation Solution
The interleaving laser ablation process, which involves creating a surface profile with both non-overlapped and overlapped laser spots, reduces diffraction severity by minimizing peak-to-valley height and increasing heat dissipation, thereby improving the optical and electrical properties of the ablated surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional laser ablation process is used to remove material from the substrate, then material removal efficiency is improved, but diffraction artifacts are generated on the surface due to periodic arrangement of laser spots
Solution Approach 1:
The patent applies asymmetry by using different laser spot patterns in alternating scan passes. Odd passes create spots at one spatial arrangement while even passes create spots at a different arrangement, breaking the periodic symmetry that causes diffraction artifacts. This asymmetric approach maintains material removal efficiency while eliminating the harmful diffraction effects.
Solution Approach 2:
The patent uses periodic action by alternating between different laser scanning patterns in successive passes. The laser applies periodic pulses with varying spatial arrangements, where each pass follows a predetermined pattern and alternating passes use different patterns. This periodic variation in spot arrangement prevents the formation of consistent diffraction artifacts while maintaining efficient material removal.
2Speed
If laser spots are arranged in a periodic pattern for efficient scanning, then scanning speed is improved, but surface quality deteriorates due to diffraction severity
Solution Approach 1:
The patent segments the laser scanning process into multiple passes with different spot patterns. Instead of using a single periodic pattern throughout, the process divides scanning into odd and even passes, each with distinct spatial arrangements. This segmentation allows maintaining high scanning speeds while improving surface quality by eliminating diffraction artifacts through pattern variation.
Solution Approach 2:
The patent introduces dynamics by changing the laser spot arrangement dynamically between passes. The system transitions from a static periodic pattern to a dynamic approach where the spatial arrangement of spots changes based on the pass number. This dynamic adjustment of patterns between odd and even passes maintains scanning efficiency while achieving superior surface quality.
3Productivity
If high laser energy is applied to increase ablation rate, then productivity is improved, but surface damage increases due to excessive heat accumulation
Solution Approach 1:
The patent applies local quality by creating different thermal histories at different spatial locations through alternating scan patterns. Areas scanned in odd passes experience different heating cycles compared to areas scanned in even passes. This variation in local thermal exposure prevents uniform heat accumulation, allowing high ablation rates while reducing overall surface damage through distributed thermal management.
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 interleaving laser ablation process effectively reduces light diffraction, minimizes damage to the surface, and enhances the conductivity and optical clarity of the ablated surface, facilitating more efficient material removal and improved performance in electrochromic devices.
Implementation Method 1
Laser ablation processes often produce artifacts on the workpiece surface
Implementation Method 2
The substrate is at least partially transparent to visible light
Implementation Method 3
The at least one of the conductive layer or the coating layer are disposed over at least a portion of the substrate
Data Source
AI summary
A product includes a substrate, at least one of a conductive layer or a coating layer, and an ablated surface on the substrate. The substrate is at least partially transparent to visible light. The at least one of the conductive layer or the coating layer are disposed over at least a portion of the substrate. The ablated surface includes an interleaved surface profile having a plurality of non-overlapped laser spots and a plurality of overlapped laser spots formed by subjecting the substrate to an interleaving laser ablation process.