Laminated Windshield Structure for Outer-Impact Resistance

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing windshields lack sufficient impact resistance, leading to a risk of the inner glass plate breaking and peeling off from the interlayer film when subjected to external impacts.

Innovation Solution

A windshield configuration with an inner and outer glass plate bonded by an interlayer film that includes a functional layer and multiple adhesive layers, where the interlayer film has specific thicknesses and moduli to enhance impact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional interlayer film with a single adhesive layer is used, then the structure is simple and easy to manufacture, but the impact resistance is insufficient and the inner glass plate may break and peel off from the interlayer film

Engineering Contradiction:
Improveimpact resistanceVSAvoidinterlayer film structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The interlayer film is segmented into multiple functional layers: a first adhesive layer (0.9mm or more thick) disposed closer to the outer glass plate, a functional layer (thermal reflection or antireflection film), and a second adhesive layer disposed closer to the inner glass plate. This segmentation allows each layer to perform its specific function, with the thick first adhesive layer providing impact absorption and peeling prevention while the functional layer provides optical or thermal functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The interlayer film uses composite material structure combining resin adhesive layers with functional films. The first adhesive layer has specific thickness (0.9mm or more) and the functional layer is integrated within the interlayer film structure, creating a composite material system that simultaneously achieves impact resistance, peeling prevention, and optical/thermal functions.

Inventive Principle:
Principle #40Composite materials

2Strength

If the first adhesive layer thickness is increased to 0.9mm or more, then the impact resistance and peeling prevention are improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvepeeling resistanceVSAvoidadhesive layer thickness control
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The thickness of the first adhesive layer is specifically controlled to be 0.9mm or more, which is a critical parameter change. This thickness parameter provides sufficient material volume to absorb impact energy and prevent peeling between the inner glass plate and interlayer film, while the patent establishes this as a clear design specification that can be controlled during manufacturing.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the outer glass plate thickness is increased to 2.3mm or more, then the impact resistance from the vehicle exterior side is improved, but the overall weight increases

Engineering Contradiction:
Improveimpact resistanceVSAvoidwindshield weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The glass plate thickness is optimized locally: the outer glass plate is set to 2.3mm or more to provide sufficient impact resistance against external objects, while the inner glass plate is kept at 2.0mm or less to reduce weight. This local quality differentiation allows each glass plate to have the minimum necessary thickness for its specific functional requirement.

Inventive Principle:
Principle #3Local quality

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 windshield design improves impact resistance by effectively absorbing and distributing external impacts, preventing the inner glass plate from peeling and scattering.

Implementation Method 1

the interlayer film includes a functional layer and has impact resistance against impact from the vehicle exterior side

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

an interlayer film that bonds the outer glass plate and the inner glass plate together

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4678610A1windshield
Publication Date: 2026.01.14 NIPPON SHEET GLASS CO LTD
  • EP4678610A1 patent drawingFigure 1~2
  • EP4678610A1 patent drawingFigure 3~4
  • EP4678610A1 patent drawing

AI summary

The present invention provides a windshield that comprises: an inner glass plate that is disposed on the vehicle interior side; an outer glass plate that is disposed on the vehicle exterior side so as to face the inner glass plate; and an interlayer film that bonds the outer glass plate and the inner glass plate together, wherein the interlayer film is provided with a functional layer and has impact resistance against impacts from the vehicle exterior side.