Laminated Composite Pane Structure for Low-Visibility Switchable Elements

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Solution Overview

Problem

Existing composite panes with electrically switchable functional elements, such as sensors and touch sensors, often appear conspicuous due to visible encapsulations or air pockets, and require complex structures like frame films to integrate these elements inconspicuously and protect them from environmental influences.

Innovation Solution

A composite pane design featuring a thermoplastic intermediate layer with a first laminating film of at least 0.3 mm thickness and thinner second laminating films (up to 70 μm) for embedding electrically switchable functional elements, ensuring adhesion and minimizing visible edges, with the second laminating films only present in the functional element area to maintain a sleek appearance and reduce mechanical stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If functional elements are embedded in the thermoplastic intermediate layer, then the visual appearance is improved and edges are minimized, but the manufacturing complexity increases

Engineering Contradiction:
Improvevisual appearanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The thermoplastic intermediate layer is segmented into two distinct parts: a first thermoplastic intermediate layer covering the entire pane surface, and a second thermoplastic intermediate layer that is applied only in the area of the functional element. This segmentation allows the functional element to be embedded with minimized edges while maintaining overall structural integrity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second thermoplastic intermediate layer is applied locally only in the functional element area rather than uniformly across the entire pane. This local application minimizes the thickness differences and visible edges around the functional element while maintaining adhesion where needed

Inventive Principle:
Principle #3Local quality

2Reliability

If thermoplastic composite films are used to integrate functional elements, then adhesion is improved, but the thickness of the composite pane increases unfavorably

Engineering Contradiction:
ImproveadhesionVSAvoidthickness of composite pane
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The second thermoplastic intermediate layer is applied locally only in the functional element area rather than across the entire pane surface. This localized approach maintains adhesion where the functional element requires it, while avoiding unnecessary thickness increase in other areas of the composite pane

Inventive Principle:
Principle #3Local quality

3Shape

If the thermoplastic intermediate layer is made thinner in the functional element area, then the visible edges are reduced, but the adhesion may be compromised

Engineering Contradiction:
Improveedge visibilityVSAvoidadhesion
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

A second thermoplastic intermediate layer is applied specifically in the functional element area to compensate for the reduced thickness of the first layer, ensuring that adhesion is maintained locally where the functional element is embedded, while the overall thickness in other areas remains minimized

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The thermoplastic intermediate layer is constructed as a composite of two different thermoplastic layers with different thicknesses and application areas. This composite structure allows optimization of both adhesion (through the second layer in functional element area) and edge visibility (through the thinner first layer in non-functional areas)

Inventive Principle:
Principle #40Composite materials

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 allows for the inconspicuous integration of functional elements, avoids air pockets, and reduces mechanical stresses, resulting in a visually appealing and durable composite pane with improved adhesion and weight optimization.

Implementation Method 1

a thermoplastic intermediate layer (5) which connects the inside surface (III) of the first pane (3) to the inside surface (II) of the second pane (4)

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3784490B1Composite pane having an electrically switchable functional element in a thermoplastic intermediate layer
Publication Date: 2024.09.11 SAINT GOBAIN SEKURIT FRANCE
  • EP3784490B1 patent drawingFigure 1a~1b
  • EP3784490B1 patent drawingFigure 1c~2
  • EP3784490B1 patent drawingFigure 3

AI summary

The invention relates to a composite pane (1) having an electrically switchable functional element (2), at least comprising a first pane (3), a second pane (4) and a thermoplastic intermediate layer (5) which connects the first pane (3) to the second pane (4), including a first laminating film (5.1) with a thickness of at least 0.3 mm and one or more second laminating films (5.2) with a thickness of max. 70 µm respectively, wherein: the first laminating film (5.1) is introduced substantially flat between the first pane (3) and the second pane (4); the second laminating films (5.2) are introduced exclusively in the region of the at least one functional element (2) with a protrusion x of at least 1 mm and they protrude over the outer edges of the functional element (2) by max. 10 mm; and the direct layer sequence in the region of an electrically switchable functional element (2) consists of the first pane (3), the second laminating film (5.2), the electrically switchable functional element (2), optionally a further second laminating film (5.2), the first laminating film (5.1) and the second pane (4).