Wedge-Shaped Laminated Glass Forming for Convex Thickness Control

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Solution Overview

Problem

Existing methods fail to provide a practical process for producing sheet glass with a convex shape in the width direction, particularly lacking details on roll arrangement and peripheral speed, making it difficult to achieve the desired thickness profile.

Innovation Solution

A process involving floating a glass ribbon on a molten metal bath, heating edge portions more intensely than the central portion, and controlling roll speeds to form a glass ribbon with thinner edges and thicker central section, using specific heating and cooling rates to manage viscosity and shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If both edge portions of the glass ribbon are heated more intensely than the central portion, then the viscosity of edge portions is maintained at lower levels allowing spreading, but the glass ribbon thickness distribution becomes non-uniform with thinner edges and thicker center

Engineering Contradiction:
Improvethickness distributionVSAvoidthickness uniformity
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The patent applies local quality by heating different regions of the glass ribbon differently - edge portions are heated more intensely than the central portion. This creates localized temperature differences that maintain lower viscosity at the edges, allowing the glass to spread laterally and form a convex thickness profile with thinner edges and thicker center, achieving the desired non-uniform thickness distribution for HUD applications.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the temperature parameter locally across the glass ribbon width. By controlling the heating intensity to be higher at edge portions and lower at the central portion, the viscosity parameter varies spatially - lower at edges (allowing spreading) and higher at center (maintaining thickness). This parameter change approach enables precise control over the final thickness profile.

Inventive Principle:
Principle #35Parameter changes

2Shape

If upstream rolls are rotated at lower peripheral speed than downstream rolls, then the glass ribbon spreads toward both sides of the rotary shafts, but the production process complexity increases

Engineering Contradiction:
Improveconvex profileVSAvoidroll speed control
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The patent applies dynamics by implementing variable rotational speeds across different rolls in the sequence. Upstream rolls operate at lower peripheral speeds than downstream rolls, creating a dynamic speed profile along the glass ribbon path. This speed gradient enables the glass to spread laterally toward both sides of the rotary shafts, forming the convex thickness profile while the system remains controllable through coordinated roll speed adjustments.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the glass ribbon is formed with thinner edge portions and thicker central portion, then double image generation is eliminated for HUD, but the production process lacks sufficient disclosed information on roll arrangement and peripheral speed

Engineering Contradiction:
ImproveHUD performanceVSAvoidprocess details
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent provides feedback by specifying precise operational parameters - upstream rolls have lower peripheral speed than downstream rolls, and edge portions are heated more intensely than the center. These feedback-controlled parameters ensure the glass ribbon achieves the correct convex thickness profile, eliminating double image generation in HUD applications while making the process reproducible through documented specifications.

Inventive Principle:
Principle #23Feedback

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 process effectively produces sheet glass with a convex shape, minimizing double images and ensuring clear visibility by maintaining a significant thickness difference between edges and center, suitable for laminated glass applications.

Implementation Method 1

floating and advancing a glass ribbon on a molten metal surface in a molten metal bath

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

heating both edge portions of the glass ribbon more intensely than a central portion of the glass ribbon in the width direction in an upstream zone of the molten metal bath

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 3

bringing a plurality of rolls into contact with both edge portions of the glass ribbon in a width direction of the glass ribbon

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3708546B1Lamninated glass with a wedge-shaped glass sheet
Publication Date: 2026.01.14 AGC INC
  • EP3708546B1 patent drawingFigure 1(A)~1(B)
  • EP3708546B1 patent drawingFigure 2
  • EP3708546B1 patent drawingFigure 3(A)~3(C)

AI summary

Provided is a float sheet glass production process for properly producing sheet glass having a convex shape in a width direction orthogonal to the advancing direction of a glass ribbon. A sheet with a wedge shape may be produced and laminated to a second glass sheet via an interlayer.