Laser-Etched Glass Shaping for Tight Tolerances After Reforming

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Solution Overview

Problem

Traditional methods for fabricating glass articles face challenges in achieving low dimensional tolerances and uniformity, particularly with shaped glass, due to dimensional deformation during reforming, annealing, and chemical strengthening, and CNC machining methods can cause surface waviness and undesired deformation.

Innovation Solution

A method involving the creation of laser damage regions on a glass substrate sheet using a pulsed laser beam, followed by ion-exchange strengthening and chemical etching with a hydrofluoric acid and hydrochloric acid solution, allows for precise shaping and separation of glass articles while minimizing surface waviness and deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional CNC machining methods are used to create through-features in glass, then holes and features can be formed, but non-uniform heating during glass reforming occurs that leads to surface waviness and undesired deformation

Engineering Contradiction:
Improveability to create through-featuresVSAvoidsurface flatness and dimensional accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies laser damage and etching to create through-features in the glass substrate before the reforming process. By pre-forming the features when the glass is flat and stable, the subsequent reforming process does not cause non-uniform heating or deformation of the features, thereby maintaining surface flatness and dimensional accuracy while still enabling through-features to be created

Inventive Principle:
Principle #10Preliminary action

2Strength

If glass articles undergo reforming, annealing, and chemical strengthening processes, then the glass can be shaped and strengthened, but dimensional deformation occurs making it challenging to meet low dimensional tolerances

Engineering Contradiction:
Improveglass strength through ion-exchange strengtheningVSAvoiddimensional tolerance
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent performs laser damage and etching to create precise features in the glass substrate before undergoing reforming, annealing, and chemical strengthening processes. By establishing the precise dimensional features early when the glass is in its initial state, the subsequent thermal and chemical processes do not compromise the dimensional tolerances, while the glass still receives the strength benefits from ion-exchange strengthening

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If laser damage regions are created and etched before strengthening, then precise shaping and separation can be achieved, but the glass may be more vulnerable to damage during subsequent processing

Engineering Contradiction:
Improveshaping accuracy and separation precisionVSAvoidglass integrity during processing
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent creates laser damage regions and performs etching to achieve precise shaping and separation before the glass undergoes ion-exchange strengthening. The strengthening process then reinforces the glass structure, including the etched regions, thereby maintaining shaping accuracy while improving the glass's resistance to damage during subsequent handling and processing

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 enables the production of glass articles with improved strength and reduced surface loss, achieving higher edge strength and accuracy in three-dimensional shapes compared to traditional CNC machining methods.

Implementation Method 1

translating a pulsed laser beam on the glass substrate sheet to form a laser damage region

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

The pulsed laser beam is operated such that an energy applied to the glass substrate sheet is at or above a damage threshold of the glass substrate sheet

Methodology Applied
Scientific EffectLaser heating: Heating

Implementation Method 3

applying the glass substrate sheet with an etchant solution comprising about 1M to about 3M of hydrofluoric acid and hydrochloric acid

Methodology Applied
Scientific EffectChemical etching:

Implementation Method 4

strengthening the glass substrate sheet by an ion-exchange strengthening process

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Implementation Method 5

preheating the glass substrate sheet to a preheated temperature, and then heating the local area of the glass substrate sheet to a localized temperature that is greater than the preheated temperature, thereby bending the glass substrate sheet at the local area

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2925690B1Methods of fabricating glass articles by laser damage and etching
Publication Date: 2021.08.11 CORNING INC
  • EP2925690B1 patent drawingFigure 1
  • EP2925690B1 patent drawingFigure 2
  • EP2925690B1 patent drawingFigure 3

AI summary

Methods of forming a glass article are disclosed. In one embodiment, a method of forming a glass article includes translating a pulsed laser beam on a glass substrate sheet to form a laser damage region between a first surface and a second surface of the glass substrate sheet. The method further includes applying an etchant solution to the glass substrate sheet to remove a portion of the glass substrate sheet about the laser damage region. The method may further include strengthening the glass substrate sheet by an ion-exchange strengthening process, and coating the glass substrate sheet with an acid-resistant coating. Also disclosed are methods where the laser damage region has an initial geometry that changes to a desired geometry following the reforming of the glass substrate sheet such that the initial geometry of the laser damage region compensates for the bending of the glass substrate sheet.