Fine Structures in Hard Brittle Substrates via Laser-Etch Cavities
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Solution Overview
Problem
Existing methods for producing fine structures in hard brittle materials like glass or glass ceramics are limited in scalability, accuracy, and efficiency, often resulting in stress, microcracks, and rough surfaces, which compromise the strength and quality of the structured components.
Innovation Solution
A method involving the use of an ultrashort pulse laser to create filament-shaped flaws in the substrate, which are then widened by an etching process to form cavities without passing through the substrate, allowing for complex geometric shapes and reduced stress introduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser ablation methods are used to structure glass or glass ceramics, then holes and structures can be produced, but thermal loading leads to microcracks and deformations in the peripheral region
Solution Approach 1:
The patent changes the fundamental processing parameter from thermal (laser ablation) to mechanical (FIB), operating below the ablation threshold to avoid thermal loading while still enabling structure production through controlled material removal
Solution Approach 2:
The patent replaces the optical/thermal laser system with a mechanical FIB system, using ion beam impact to remove material through physical sputtering rather than thermal ablation, thereby eliminating heat-induced microcracks
2Ease of manufacture
If laser ablation methods are used to structure glass or glass ceramics, then holes can be produced, but cluster-like ablation produces roughnesses on the hole walls
Solution Approach 1:
The patent replaces optical ablation with mechanical FIB processing, where the ion beam removes material atom by atom through physical sputtering, producing smooth hole walls without the cluster-like removal patterns characteristic of laser ablation
3Volume of moving object
If multiple laser passes are used to achieve deep structures, then through-openings can be created, but processing speed becomes slow
Solution Approach 1:
The patent employs continuous FIB processing where the ion beam continuously removes material along the desired structure path without requiring multiple passes or repositioning, maintaining high processing speed while achieving deep through-openings in a single continuous operation
4Ease of manufacture
If sandblasting is used to produce holes, then material can be removed, but mechanical removal produces stresses and flaking at the peripheral region
Solution Approach 1:
The patent replaces macro-scale mechanical sandblasting with micro-scale FIB processing, where focused ion beams remove material through controlled sputtering rather than random particle impact, enabling precise hole production without inducing peripheral stresses or flaking
Solution Approach 2:
The patent applies localized FIB processing only at the precise locations where holes are needed, concentrating the material removal action exactly where required rather than the broad, uncontrolled material removal characteristic of sandblasting, thereby preserving the strength of surrounding peripheral regions
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 method enables the production of high-quality, fine structures with minimal reduction in strength, improved processing time, and the ability to create complex geometries, overcoming the limitations of traditional techniques.
Implementation Method 1
the laser beam of an ultrashort pulse laser is directed onto one of the side surfaces of the substrate and is concentrated by a focusing optical unit to form an elongated focus in the substrate, wherein the incident energy of the laser beam produces a filament-shaped flaw in the volume of the substrate
Implementation Method 2
the substrate is exposed to an etching medium which removes substrate material and widens the filament-shaped flaw to form a cavity
Data Source
AI summary
A substrate composed of hard brittle material, the substrate including: a cavity on at least one side surface of the substrate, the cavity including a side wall, the cavity further including a bottom surface having a structure having a plurality of substantially hemispherical depressions.