Thin Chemically Strengthened Glass for Solar Control Laminates

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Solution Overview

Problem

Existing automotive and architectural glass applications face challenges in achieving desired solar performance and durability in thin glass articles due to limitations in chemical strengthening and the need for higher dopant amounts in thinner glass, which affects weight and fuel efficiency.

Innovation Solution

A glass composition with specific transition metals like iron, cobalt, vanadium, and nickel, controlled redox states, and balanced alkali metal oxides to achieve chemical strengthening and desired solar performance in thin glass articles, eliminating the need for polymer interlayers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thermal tempering is used to strengthen glass articles, then glass strength is improved, but the surface compressive stress magnitude is limited to less than 100 MPa and the method becomes increasingly ineffective for thin glass articles (thickness less than 2 mm)

Engineering Contradiction:
Improveglass strengthVSAvoideffectiveness for thin glass articles
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent transitions from thermal tempering to chemical strengthening via ion exchange, fundamentally changing the strengthening mechanism. This allows achieving high surface compressive stress (up to 1,000 MPa) in thin glass articles (0.3-2.0 mm thickness) that cannot be effectively thermally tempered, thus resolving the limitation of thermal tempering for thin glass applications

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If thicker glass articles are used to achieve desired solar performance, then solar transmission characteristics are improved, but component weight increases and fuel efficiency decreases

Engineering Contradiction:
Improvefuel efficiencyVSAvoidsolar performance characteristics
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent uses chemical strengthening to achieve high strength in thin glass articles (0.3-2.0 mm), allowing replacement of thicker glass while maintaining required performance. This reduces weight and improves fuel efficiency while the specific glass composition with transition metals (Fe, Co, Ni, V) ensures desired solar transmission characteristics are achieved in the thinner configuration

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite glass composition containing multiple transition metals (Fe, Co, Ni, V) in specific amounts to achieve both mechanical strength and optical performance in thin glass articles, eliminating the need for thicker single-material glass solutions

Inventive Principle:
Principle #40Composite materials

3Weight of moving object

If thinner glass articles are used to reduce weight, then weight and fuel efficiency are improved, but durability is reduced due to strengthening limitations of currently available thin glass articles

Engineering Contradiction:
Improvecomponent weightVSAvoiddurability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent applies chemical strengthening via ion exchange to thin glass articles (0.3-2.0 mm), achieving surface compressive stress up to 1,000 MPa and depth of compression up to 75 micrometers. This chemical strengthening mechanism overcomes the inherent weakness of thin glass, providing the necessary durability while maintaining weight reduction benefits

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a localized compressive stress layer through ion exchange that concentrates strength enhancement at the glass surface where it is most needed for impact resistance, while the bulk glass remains thin and lightweight. The compressive layer depth is controlled to optimize both strength and weight

Inventive Principle:
Principle #3Local quality

4Object-affected harmful factors

If higher amounts of dopants are added to thinner glass articles to achieve same transmission characteristics, then solar performance is maintained, but the glass composition becomes more complex and manufacturing difficulty increases

Engineering Contradiction:
Improvetransmission characteristicsVSAvoidmanufacturing difficulty
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent optimizes the glass composition with specific ranges of transition metals (Fe: 0.01-1.0 wt%, Co: 0.01-0.5 wt%, Ni: 0.01-0.5 wt%, V: 0.01-0.5 wt%) to achieve desired solar transmission in thin glass articles without requiring excessive dopant amounts, balancing optical performance with manufacturing feasibility

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

The glass composition achieves comparable solar performance to thicker glass articles while reducing weight and maintaining durability, providing significant weight reduction and improved fuel efficiency.

Implementation Method 1

the chemical strengthening using an ion exchange process can create high levels of compressive stress (e.g., as great as 1,000 MPa), and is suitable for very thin glass

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Implementation Method 2

Selective absorption in the different regions of the light spectrum can be achieved by the addition of transition metals. Iron for example is a common addition to glass since it has selective absorption in all the regions of the light spectrum

Methodology Applied
Scientific EffectSelective absorption: Absorption (EM radiation)

Data Source

PatentEP3544935B1Automotive and architectural glass articles and laminates
Publication Date: 2025.11.12 CORNING INC
  • EP3544935B1 patent drawingFigure 1
  • EP3544935B1 patent drawingFigure 2
  • EP3544935B1 patent drawingFigure 3

AI summary

Embodiments of glass articles exhibiting a grey or a green tint are described. In one or more embodiments, the glass article comprises a glass composition including SiO2, A12O3B2O3 or MgO, a non-zero amount of alkali metal oxides (R2O), R2O - A12O3 in the range from about -0.5 to about 1.5; and up to 1 mol% Fe2O3. In one or more embodiments, the glass composition includes a ratio of R2O to A12O3 equal to or greater than about 1, Na2O, from 0-13 mol% MgO, at least one of K2O, SnO2 and TiO2. Laminates including such glass articles and methods of making the glass articles are also described.