Non-ablative Laser Patterning of Transparent Conductive Films
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Solution Overview
Problem
Current laser patterning techniques for transparent conductive films are inefficient due to high cycle times, costly consumables, toxic waste, and visible marks on the surface, particularly when processing flexible substrates, where a protective film must be removed and reattached, leading to increased processing delays and expenses.
Innovation Solution
A method using pulsed laser beams with selected parameters to change the conductivity of a conductive layer on transparent substrates without ablating the material, allowing for non-ablative processing that maintains the structural integrity and visibility of the surface, and omits the need to remove the protective layer during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser processing techniques are used to pattern transparent conductive films, then material is removed to create conductive patterns, but visible marks are left on the surface and cycle time increases
Solution Approach 1:
The patent changes the laser processing parameters from high-energy ablation mode to low-energy non-ablative mode. By operating below the ablation threshold and using pulsed laser parameters (wavelength, pulse duration, fluence) that induce conductive-to-nonconductive transitions without material removal, the process achieves both high surface quality and efficient processing speeds
Solution Approach 2:
The patent replaces the mechanical ablation process with a field-based optical process. Instead of using high-energy laser ablation to physically remove material, the invention uses non-ablative laser irradiation that induces electrical property changes through optical field interactions, eliminating visible surface marks while maintaining processing efficiency
2Manufacturing precision
If photolithography or screen printing techniques are used for touch sensor patterning, then conductive patterns can be created, but expensive consumables and toxic waste are generated
Solution Approach 1:
The patent extracts and eliminates the need for photolithographic consumables (photoresists, masks, etchants) and screen printing materials by using direct laser-induced conductive-to-nonconductive transitions. The process patterns the conductive film in-situ without requiring external patterning materials or chemical processing steps
Solution Approach 2:
The conductive film itself serves as the patterned structure through selective property modification. The laser processing directly transforms regions of the conductive film from conductive to nonconductive states, allowing the material to define the pattern without requiring separate masking or resist layers
3Ease of manufacture
If a protective film is removed and reattached during processing of flexible substrates, then the substrate can be processed, but substantial processing delays and increased expenses occur
Solution Approach 1:
The patent performs preliminary laser patterning of the conductive film while the protective film remains in place. By conducting the conductive-to-nonconductive transitions through the protective layer without removing it, the process eliminates the need for protective film removal and reattachment steps
Solution Approach 2:
The protective film serves multiple functions simultaneously: it protects the substrate during handling and processing, and allows laser energy to penetrate through to induce conductive-to-nonconductive transitions in the underlying conductive film. This multi-functionality eliminates the need to remove the protective layer
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 cycle times, eliminates visible marks, and lowers processing costs by enabling true roll-to-roll processing with ultra-low visibility of processed areas, maintaining the substrate's structural integrity and reducing the need for additional protective measures, thus enhancing the efficiency and cost-effectiveness of touch sensor and display device manufacturing.
Implementation Method 1
laser parameters selected for non-ablatively changing a conductive layer disposed on the transparent substrate into a non-conductive feature
Implementation Method 2
exposure to a laser pulse having selected laser pulse parameters causes the conductive material to become non-conductive material without ablating the material layer
Data Source
AI summary
A method for processing a transparent substrate includes generating at least one laser pulse having laser parameters selected for non-ablatively changing a conductive layer disposed on the transparent substrate into a non-conductive feature, and directing the pulse to said conductive layer. A protective film may be affixed to a surface of the transparent substrate and need not be removed during the processing of the substrate. After processing, processed areas can be visually indistinguishable from unprocessed areas.