Laminated Glass with Variable Thickness for Wrinkle Reduction

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Solution Overview

Problem

The challenge is to produce a lightweight laminated glass for vehicle windows with reduced wrinkle formation, particularly when using chemically strengthened glass plates of smaller thickness, which are difficult to curve in multiple directions without delamination or thickness mismatch issues in the adhesive layer.

Innovation Solution

A laminated glass configuration where a first glass plate with a larger thickness is paired with a second glass plate of lesser thickness, both having curved shapes, with the second glass plate's convex surface laminated onto the first glass plate's concave surface via an intermediate film, ensuring the second glass plate's outer peripheral edge is inside the first glass plate's edge, and featuring a central region with a greater curvature radius than the outer peripheral region, reducing wrinkle occurrence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a chemically strengthened glass plate with smaller plate thickness is used, then weight is reduced, but wrinkle formation occurs during curved shaping

Engineering Contradiction:
Improveweight of glass plateVSAvoidwrinkle formation
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The first glass plate is pre-curved to the target curvature before lamination, and the second glass plate is then forced to follow this pre-established curve. This preliminary action of curving the first plate provides a stable template that guides the second plate into the desired shape, preventing wrinkle formation during the forcing process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The glass structure is divided into two separate glass plates with different thicknesses and curvature characteristics. The first glass plate serves as the primary curved structure, while the second glass plate is a thinner overlay that conforms to the first plate's curve. This segmentation allows each plate to have optimized properties for its specific function

Inventive Principle:
Principle #1Segmentation

2Shape

If an uncurved glass plate is forcibly deformed to follow a glass plate curved in two orthogonal directions, then curvature is achieved, but wrinkle occurs in the edge portion

Engineering Contradiction:
Improvecurved shapeVSAvoidwrinkle in edge portion
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The first glass plate is pre-curved to the target curvature before lamination, and the second glass plate is then forced to follow this pre-established curve. This preliminary action of curving the first plate provides a stable template that guides the second plate into the desired shape, preventing wrinkle formation during the forcing process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The second glass plate is designed with non-uniform thickness, being thinner at the edge portions and thicker in the central region. This local variation in thickness allows the edge portions to more easily conform to the curved surface of the first plate without generating wrinkles, while the thicker central region maintains structural integrity

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If the adhesive layer thickness is increased to absorb curvature mismatch, then wrinkle is reduced, but delamination or significant thickness variation occurs

Engineering Contradiction:
Improvecurvature matchingVSAvoidadhesive layer uniformity
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The second glass plate is designed with non-uniform thickness, being thinner at the edge portions and thicker in the central region. This local variation in thickness allows the edge portions to more easily conform to the curved surface of the first plate without generating wrinkles, while the thicker central region maintains structural integrity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The thickness of the second glass plate is varied as a parameter to control its ability to conform to the curved first plate. By making the second plate thinner at edges and thicker in the center, the patent optimizes the balance between conformability and structural stability without relying on excessive adhesive layer thickness

Inventive Principle:
Principle #35Parameter changes

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 configuration effectively reduces wrinkle formation and enhances the bonding strength between glass plates, allowing for a lightweight, aerodynamically efficient vehicle window with improved curvature matching and reduced weight while maintaining structural integrity.

Implementation Method 1

an intermediate film, and a second glass plate (12), wherein the first glass plate (11) and the second glass plate (12) are laminated via the intermediate film (14)

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3266610B1Laminated glass and vehicle window
Publication Date: 2021.09.08 AGC INC
  • EP3266610B1 patent drawingFigure 1A~1C
  • EP3266610B1 patent drawingFigure 2
  • EP3266610B1 patent drawingFigure 3A~3C

AI summary

A laminated glass includes a first glass plate; a second glass plate with a plate thickness which is less than a plate thickness of the first glass plate; and an intermediate film. The first glass plate and the second glass plate are laminated via the intermediate film. An external dimension of the second glass plate is less than an external dimension of the first glass plate. At least a part of an outer peripheral edge of the second glass plate is located on an inner periphery side with respect to an outer peripheral edge of the first glass plate.