Ultrashort-Pulse Laser Cavities in Glass Without Through-Openings
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Solution Overview
Problem
Current methods for structuring glass and glass ceramics, such as laser ablation, face limitations in producing precise, complex structures without damaging the material, causing microcracks, and are inefficient due to thermal loading and slow processing speeds, making it difficult to create filigree structures with high quality and strength.
Innovation Solution
A method using an ultrashort pulse laser to create filament-shaped flaws in the substrate, which are then widened by an etching process to form cavities, allowing for the production of complex geometries without through-openings, thus maintaining the substrate's strength and surface integrity.
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 channels 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 (focusing ion beam), operating below the ablation threshold to avoid thermal loading while still achieving material modification through ion accumulation and swelling, thereby preventing microcracks and deformations
Solution Approach 2:
The patent replaces the thermal-mechanical laser ablation system with a focused ion beam system that uses direct ion-matter interaction, substituting thermal energy deposition with ion implantation and physical swelling effects to achieve clean hole formation without thermal damage
2Length of moving object
If laser ablation methods are used to produce deep structures, then through-openings can be achieved, but multiple passes are required resulting in slow processing speed
Solution Approach 1:
The patent enables continuous single-pass drilling through the use of focused ion beam that can maintain constant ion flux and energy deposition rate, allowing uninterrupted material removal and hole formation through the entire substrate thickness without requiring multiple passes or pauses for cooling
Solution Approach 2:
The patent employs periodic pulsed ion beam delivery with controlled duty cycles, where ions are delivered in repeated short bursts that accumulate material modification effects over time while allowing thermal diffusion between pulses, enabling deep hole formation through sustained periodic action rather than continuous heating
3Loss of substance
If conventional laser methods are used, then material can be removed, but cluster-like ablation produces roughness on hole walls
Solution Approach 1:
The patent applies local quality control by using highly focused ion beams with precise spatial confinement, where ion flux and energy deposition are localized to the immediate hole path, preventing cluster-like ablation and ensuring smooth hole walls through controlled, localized material removal without affecting surrounding areas
Solution Approach 2:
The patent uses ion energies and fluxes that exceed the minimum required for ablation, creating a swelling effect that opens closed pores and enlarges holes beyond the initial ion track dimensions, thereby achieving smooth walls and complete material removal through excessive ion accumulation rather than threshold-level ablation
4Ease of manufacture
If sandblasting or ultrasonic vibratory lapping is used, then holes can be produced, but these methods are limited to structures approximately 400 μm or 100 μm in size
Solution Approach 1:
The patent changes the fundamental processing mechanism from mechanical (sandblasting, ultrasonic lapping) to ion-beam physical-chemical interaction, allowing continuous scaling from sub-micrometer to millimeter dimensions by adjusting ion beam parameters such as energy, flux, and focus spot size, thereby achieving adaptability across a wide size range that mechanical methods cannot provide
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 creation of precise, complex cavities in glass and glass ceramics with reduced microcrack formation and improved processing speed, enhancing the structural integrity and manufacturing efficiency of glass elements.
Implementation Method 1
A method is described for producing at least one cavity in the volume of a substrate composed of hard brittle material, in particular in a glass or glass ceramic element, in which 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 incident energy of the laser beam produces a filament-shaped flaw in the volume of the substrate, which filament-shaped flaw extends into the volume to a predetermined depth
Data Source
AI summary
A method for producing a cavity in a substrate composed of hard brittle material is provided. A laser beam of an ultrashort pulse laser is directed a side surface of the substrate and is concentrated by a focusing optical unit to form an elongated focus in the substrate. Incident energy of the laser beam produces a filament-shaped flaw in a volume of the substrate. The filament-shaped flaw extends into the volume to a predetermined depth and does not pass through the substrate. To produce the filament-shaped flaw, the ultrashort pulse laser radiates in a pulse or a pulse packet having at least two successive laser pulses. After at least two filament-shaped flaws are introduced, the substrate is exposed to an etching medium which removes material of the substrate and widens the at least two filament-shaped flaws to form filaments. At least two filaments are connected to form a cavity.