Laser-Structured Glass Surface Marking Without Strength Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laser structuring of glass surfaces for marking, such as QR codes, introduces stress and microcracks, reducing the strength of glass substrates and requiring additional thermal or chemical treatment, which can lead to surface defects and breakage.
Innovation Solution
A glass surface structuring method using laser ablation that creates a stress profile with compressive stress on the surface that decreases with depth, transitioning to tensile stress, maintaining higher compressive stress than adjacent unstructured areas, thereby enhancing breaking strength while minimizing strength reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If laser ablation is used for surface structuring and marking of glass, then surface marking capability is achieved, but strength of the glass is reduced due to introduced stresses and microcracks
Solution Approach 1:
The patent converts the harmful effect of laser-induced stress into a beneficial compressive stress profile on the glass surface. By carefully controlling the laser ablation parameters, a compressive stress layer is created that actually strengthens the glass in the marked area, counteracting the typical strength-reducing effect of surface damage and microcracks.
Solution Approach 2:
The patent applies parameter changes by optimizing laser ablation conditions (pulse duration, energy density, scanning speed, pulse overlap) to control the depth and distribution of material removal. This creates a specific stress profile where compressive stress dominates at the surface and transitions to tensile stress at greater depths, with the maximum compressive stress exceeding the maximum tensile stress to ensure net strength improvement.
2Reliability
If thermal or chemical post-treatment is applied to treat microcracks from laser structuring, then surface defects are reduced, but additional process steps and risk of deformation are introduced
Solution Approach 1:
The patent extracts and eliminates the need for separate thermal or chemical post-treatment steps by integrating the stress management function directly into the laser ablation process itself. The laser parameters are optimized to create a beneficial compressive stress profile that inherently addresses microcrack formation, removing the requirement for additional treatment processes.
Solution Approach 2:
The patent merges the marking function and the stress management function into a single laser ablation process. Instead of performing marking followed by separate post-treatment, the laser parameters are controlled to simultaneously achieve both surface marking and creation of a strengthening compressive stress profile, combining multiple functions into one operation.
3Strength
If compressive stress is increased on the glass surface in structured areas, then breaking strength is improved, but stress profile control complexity increases
Solution Approach 1:
The patent uses periodic pulsed laser action to create the desired stress profile. By delivering laser energy in controlled pulses with specific timing and overlap, the material removal occurs in discrete stages that build up the compressive stress layer progressively, allowing precise control over stress distribution through the glass thickness.
Solution Approach 2:
The patent applies dynamics by making the laser processing parameters adjustable and adaptive. The pulse duration, energy, scanning speed, and overlap can be dynamically optimized for different glass types, marking patterns, and desired stress profiles, allowing flexible control without requiring complex additional equipment.
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 method significantly improves the breaking strength of glass elements in structured areas compared to conventional laser ablation, maintaining readability of markings like QR codes without the need for additional treatment processes.
Implementation Method 1
Laser ablation is a well-known technique for surface structuring of glass. This technique involves sublimating material on the surface of the glass point by point using a pulsed, intense laser beam.
Implementation Method 2
the structured region has a mechanical stress profile which can be measured in particular by means of stress birefringence and which has the following properties: the structured area has a compressive stress on the glass surface which is higher in magnitude than the stress in the adjacent unstructured area; the compressive stress decreases in magnitude with increasing depth and changes into a tensile stress
Data Source
Figure 1~4
Figure 2~3
Figure 5
AI summary
The invention is based on the objective of minimizing the reduction in strength caused by markings applied to glass using a material-removing process. For this purpose, a glass element (1) with a surface structuring (9) is provided, which comprises at least one structured area (90) of the glass surface (2) that has a higher roughness due to glass removal than an adjacent, unstructured area (91) of the glass surface (2), and wherein the structured area (90) exhibits a mechanical stress profile, measurable in particular by means of stress birefringence, wherein: - the structured area (90) exhibits a compressive stress on the glass surface (2) that is higher in magnitude than the stress in the adjacent unstructured area (91).and wherein the structured region (90) furthermore exhibits at least one of the following properties: - the compressive stress decreases in magnitude with increasing depth and transitions into a tensile stress, the maximum tensile stress being smaller in magnitude than the compressive stress at the glass surface (2) - the compressive stress at the surface has a value of less than 5 MPa in magnitude and decreases in magnitude with increasing depth.