Pair-Bent Glass Laminate Composition for Shape-Matched Forming

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional methods for forming curved glass laminates face issues with shape mismatch and optical distortions due to differences in composition, thickness, and viscosity between glass plies, leading to increased contact pressure and bending dot defects.

Innovation Solution

Modify the composition of the thicker soda lime glass ply to align its viscosity curve with that of the thinner, strengthened glass ply, ensuring similar sagging temperatures and reducing thickness differences to minimize shape mismatch and optical distortions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If glass plies with different compositions and thicknesses are used in the laminate, then the laminate can achieve enhanced strength and optical properties, but shape mismatch and optical distortions occur during co-forming due to differences in viscosity and sagging temperatures

Engineering Contradiction:
Improvestrengthening properties of glass plyVSAvoidshape consistency between glass plies
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent modifies the chemical composition of the thicker glass ply (specifically adjusting oxide content ratios) to change its viscosity characteristics and sagging temperature, aligning them with the thinner strengthened glass ply. This parameter adjustment allows both plies to be co-formed at the same temperature without shape mismatch while maintaining the strengthening properties of the thinner ply

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different glass compositions to different plies based on their specific functional requirements: the thinner ply receives composition optimized for strength (strengthened glass), while the thicker ply receives composition adjusted for viscosity matching. Each ply is locally optimized for its specific role in the laminate

Inventive Principle:
Principle #3Local quality

2Productivity

If glass plies with different thicknesses are co-formed at the same temperature, then the laminate can be manufactured efficiently, but contact pressure increases and bending dot defects occur due to unequal sagging rates

Engineering Contradiction:
Improveco-forming efficiencyVSAvoidcontact pressure and bending dot defects
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent adjusts the chemical composition of the thicker glass ply to modify its viscosity curve and sagging temperature characteristics. By changing the oxide content ratios in the thicker ply, its sagging rate is matched to the thinner ply, allowing both to deform uniformly during co-forming without excessive contact pressure or bending dot defects

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the viscosity curves of glass plies are mismatched, then different glass compositions can be used to optimize individual ply properties, but shape deviation exceeds acceptable tolerances after co-forming

Engineering Contradiction:
Improveglass composition flexibilityVSAvoidshape deviation within tolerance
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent carefully adjusts the chemical composition parameters of the thicker glass ply (oxide content ratios) to shift its viscosity curve, creating a match with the thinner strengthened glass ply. This parameter optimization allows both plies to maintain their individual property optimizations while achieving compatible deformation behavior during co-forming, keeping shape deviation within ±5mm tolerance

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

Achieves consistent shape and reduced optical distortions between glass plies, with deviations within ±5 mm and optical distortions below 400 millidiopters, while maintaining the strengthening properties of the thinner ply.

Implementation Method 1

heating the stack to a sagging temperature above the annealing temperature of both glass articles

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

heating the stack to a sagging temperature such that a shaped stack is formed, wherein the sagging temperature is above both of the first annealing temperature and the second annealing temperature

Methodology Applied
Scientific EffectGlass softening: Melting

Data Source

PatentEP3844113B1Method for pair bending glass articles and glass laminate
Publication Date: 2026.02.25 CORNING INC
  • EP3844113B1 patent drawingFigure 1~2
  • EP3844113B1 patent drawingFigure 3~4
  • EP3844113B1 patent drawingFigure 5~7

AI summary

Embodiments of a method for pair bending glass articles is provided herein. In the method, a first glass article and a second glass article are stacked to form a stack. The first glass article includes a first surface, a second surface that opposes the first surface, and a first composition having first annealing and softening temperatures. The second glass article includes a third surface, a fourth surface that opposes the third surface, and a second composition having second annealing and softening temperatures. The annealing temperatures are within 35 °C of each other and are at least 550 °C. The softening temperatures are within 35 °C of each other and are at least 750 °C. In the method, the stack is placed on a mold, and the stack is heated to a sagging temperature such that a shaped stack is formed.