Laser-Structured Glass Plate for Stronger Scratch-Resistant Cut Edges

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Solution Overview

Problem

The existing glass plate production methods face challenges in handling glass substrates during chemical strengthening, leading to difficulties in ensuring the quality of strength and external appearance of the final glass articles, with issues such as scratches and insufficient strength at the end faces.

Innovation Solution

A method involving laser irradiation to create in-plane void regions and internal void rows in a glass material, followed by chemical strengthening, which allows for the formation of a compressive stress layer even at the cut surfaces, enhancing the strength and reducing the risk of scratches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If glass substrates are handled from cutting to chemical strengthening in the related-art method, then the glass substrates can be chemically strengthened, but the glass substrates are prone to scratches on the end face and require careful handling

Engineering Contradiction:
Improvequality of strengthVSAvoid scratches on end face
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies chemical strengthening treatment to the glass material before cutting it into substrates. This preliminary action ensures that the glass is already strengthened before handling and processing, eliminating the risk of scratches on end faces that would occur if strengthening were done after cutting. The glass material is chemically strengthened in its bulk form, then cut into final substrate shapes.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If chemical strengthening is applied to a large-sized glass material in advance, then the glass material can be cut into glass articles, but the end face of the glass articles will not be chemically strengthened and insufficient strength is acquired

Engineering Contradiction:
Improvecutting of glass articlesVSAvoidstrength at end face
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent creates virtual end faces with specific void structures (in-plane void regions with voids of 0.2-10 μm diameter arranged at intervals of 1-20 μm) at the locations where end faces will eventually form. These localized void structures enable selective chemical strengthening at the end face regions while maintaining the ability to cut the glass into final article shapes. The void structures are precisely positioned to ensure that when the glass is cut, the end faces will have the necessary void patterns for chemical strengthening.

Inventive Principle:
Principle #3Local quality

3Strength

If the surface of glass material is chemically strengthened, then the glass material has improved strength, but cutting the glass articles becomes difficult

Engineering Contradiction:
Improvesurface strengthVSAvoidcutting difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent performs chemical strengthening after cutting the glass material into final article shapes, not before. This sequencing allows easy cutting of the glass material while still achieving chemical strengthening of the final substrates. The process order is: (1) cut glass material into substrates, (2) apply chemical strengthening to the cut substrates. This resolves the contradiction by performing strengthening at the appropriate stage when cutting is no longer needed.

Inventive Principle:
Principle #10Preliminary action

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 produces glass articles with improved strength and reduced risk of scratches, while maintaining the external appearance quality, by forming a compressive stress layer throughout the glass plate, including the cut surfaces, thus addressing the challenges of handling and strength consistency.

Implementation Method 1

irradiating the first main surface of the glass material with a laser to form an in-plane void region having a plurality of voids arranged on the first main surface

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

The chemical strengthening treatment is a process of immersing a glass substrate in a molten salt containing an alkali metal to replace alkali metal ions having a smaller atomic diameter present on the surface of the glass substrate with alkali metal ions having a larger atomic diameter present in the molten salt

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Data Source

PatentEP3345877B1Method for manufacturing glass plate, glass plate, method for manufacturing glass article, glass article
Publication Date: 2022.03.23 AGC INC
  • EP3345877B1 patent drawingFigure 1~2
  • EP3345877B1 patent drawingFigure 3~4
  • EP3345877B1 patent drawingFigure 5~6

AI summary

A glass plate production method includes (1) preparing a glass material having a first main surface and a second main surface opposite to each other; (2) irradiating the first main surface of the glass material with a laser to form an in-plane void region having a plurality of voids arranged on the first main surface, and forming a plurality of internal void rows each having one void or two or more voids arranged from the in-plane void region toward the second main surface of the glass material; and (3) chemically strengthening the glass material having the internal void rows formed therein.