Liquid Crystal Glazing with Laminated PVB and EVA Sealing

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Solution Overview

Problem

Existing electro-controllable liquid crystal glazing is fragile and lacks robustness, requiring improvements in mechanical strength and reliability while maintaining variable diffusion capabilities at a lower cost.

Innovation Solution

The glazing incorporates a laminated structure with transparent polymeric interlayers and enhanced electrical insulation and sealing materials, including a polyvinyl butyral (PVB) interlayer for mechanical reinforcement and a polyethylene-vinyl acetate (EVA) sealing material for watertightness, along with strategically placed electrical wiring and insulation to prevent damage and ensure secure connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a multiple liquid crystal glazing is assembled with offset glass sheets and protruding electrode edges to facilitate adhesive application, then the variable diffusion function is achieved, but the mechanical robustness and reliability are reduced

Engineering Contradiction:
Improvemechanical robustnessVSAvoidassembly structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The glazing is divided into multiple functional layers: glass sheets, liquid crystal layer, adhesive layers, and sealing elements. Each layer performs a specific function, allowing the system to achieve variable diffusion while maintaining structural integrity through proper segmentation of components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Electrode edges are intentionally designed to protrude from the glass sheets before assembly. This preliminary positioning facilitates the subsequent application of adhesive copper strips and ensures proper electrical connections, simplifying the assembly process while maintaining reliability.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If the glass sheets are offset with protruding electrode edges, then electrical connection is facilitated, but the glazing becomes fragile and less mechanically resistant

Engineering Contradiction:
Improveelectrical connection easeVSAvoidmechanical resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

Adhesive copper strips are applied to the protruding electrode edges to provide both electrical connection and mechanical reinforcement. These thin conductive films bridge the electrode edges, enabling easy electrical wiring while compensating for the reduced mechanical strength at the protruding edges.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The glazing combines multiple materials with complementary properties: glass sheets for structural support, liquid crystals for optical control, adhesive materials for bonding, and copper strips for electrical connection. This composite structure allows the system to achieve electrical connectivity without compromising overall mechanical resistance.

Inventive Principle:
Principle #40Composite materials

3Use of energy by moving object

If adhesive copper strips are applied to distribute current to electrodes, then electrical distribution is improved, but the assembly complexity and fragility increase

Engineering Contradiction:
Improveelectrical current distributionVSAvoidassembly complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The adhesive copper strips serve multiple functions simultaneously: they distribute electrical current to the electrodes, provide mechanical reinforcement to the protruding electrode edges, and act as bonding elements between layers. This multi-functionality reduces overall assembly complexity despite the additional component.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution significantly enhances the mechanical resistance and electrical security of the glazing, allowing for easier installation and compliance with building standards, while maintaining the ability to switch between transparent and translucent states, and providing protection against ultraviolet rays and moisture.

Implementation Method 1

a layer of liquid crystals reversibly alternating between a transparent state and a translucent state by application of an alternating electric field

Methodology Applied
Scientific EffectLiquid crystal electro-optic effect: Electro-Optic Effects

Data Source

PatentEP2625563B1Multiple glazing having variable diffusion by liquid crystals, and method for manufacturing same
Publication Date: 2016.12.28 SAINT GOBAIN VITRAGE SA
  • EP2625563B1 patent drawingFigure 1a~1b
  • EP2625563B1 patent drawingFigure 1c~1d
  • EP2625563B1 patent drawingFigure 2a~2b

AI summary

The invention relates to liquid-crystal multiple glazing (100), comprising: a first glass sheet (1) and a second glass sheet attached together by a seal (6); first and second electrodes (3, 3') having first and second electrical input areas (90, 31, 90', 31'); a liquid-crystal layer (4) of between 15 and 60 μm and having spacers; the first glass sheet (1) projecting by means of a first projecting edge and comprising the first electrical input area; an electric cable harness (9, 9') having a first cable inlet (90) including a first polymeric electrically insulating material (61); a third glass sheet (8) laminated with the second glass sheet (1), the third glass sheet projecting beyond the second glass sheet (1) by means of an edge covering the first electrically insulating material (61), referred to as the first covering edge (83). The invention also relates to the production of such liquid-crystal glazing.