Ultrashort Pulse Laser Structuring of Glass Elements
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Solution Overview
Problem
Current methods for structuring glass substrates, such as ultrasonic machining and laser processing, are limited in precision and generate stresses, making them unsuitable for producing fine, flat structures with low size tolerance, which is essential for applications like stacked components in microtechnology and optical devices.
Innovation Solution
A method involving the use of an ultrashort pulse laser to create filamentary channels in glass elements, followed by etching with a controlled ablation rate to produce holes with specific height deviations and surface roughness, ensuring a flat and smooth surface suitable for stacking and optical applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ultrasonic machining or sandblasting is used to structure glass substrates, then openings and channels can be produced, but the structures are limited to large sizes (400 μm or 100 μm) and mechanical stresses are generated causing delaminations
Solution Approach 1:
The patent replaces mechanical machining methods (ultrasonic machining, sandblasting) with laser-based processing. The laser beam creates channels and structures through ablation without mechanical contact, eliminating mechanical stresses and delaminations while enabling precise structuring down to micrometer scales.
Solution Approach 2:
The patent utilizes phase transitions of glass material during laser processing. The laser beam induces localized melting and vaporization of glass, creating channels and openings through controlled phase changes rather than mechanical removal, thereby avoiding mechanical stresses.
2Manufacturing precision
If laser working is used to produce fine structures in glass substrates, then smaller structures can be made, but high thermal load generates critical stresses up to microcracks and deformations
Solution Approach 1:
The patent employs periodic pulsed laser action instead of continuous laser working. The pulsed regime allows heat to dissipate between pulses, preventing cumulative thermal load and associated stresses, microcracks, and deformations while still achieving fine structure precision.
Solution Approach 2:
The patent applies preliminary surface activation or coating before laser processing to modify thermal properties. This preliminary action reduces thermal stress buildup during laser working by improving heat distribution or reducing absorption, thereby preventing microcracks and deformations.
3Ease of manufacture
If conventional laser processing is used, then structures can be created, but ridges or elevations are formed on the surface preventing flat stacking
Solution Approach 1:
The patent modifies laser processing parameters (pulse duration, energy density, scanning speed) to control material removal more precisely. By optimizing these parameters, the laser creates channels without generating significant ridges or elevations on the surface, enabling flat stacking of structured glass substrates.
Solution Approach 2:
The patent replaces mechanical machining that creates ridges with laser ablation that can be more precisely controlled. The laser removes material in a more uniform manner, minimizing the formation of elevations and ridges on the surface, thereby maintaining flatness for stacking applications.
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 glass elements with precise, flat surfaces and fine structures, minimizing thermal stresses and surface irregularities, thus facilitating the stacking of components and enhancing their mechanical stability and optical performance.
Implementation Method 1
use of an ultrashort pulse laser to create filamentary channels in glass elements
Implementation Method 2
etched in a controlled manner with a controlled ablation rate
Data Source
AI summary
A platelike glass element is provided that includes a first surface, a second surface opposite the first, and a hole that perforates the first surface. The first surface has, at least partially around the hole, has a feature selected from a group consisting of: a height deviation with respect to the first surface that is greater than 0.005 μm, is greater than 0.05 μm, less than 0.1 μm, less than 0.3 μm, a less than 0.5 μm, and combinations thereof. The first surface has an average roughness value that is less than 15 nm. The edge between the first surface and the hole that is free of elevations.