Perforated Contacting Layer for Flexible Heated Mirror Element

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Solution Overview

Problem

Conventional adhesive heating elements for automotive exterior mirrors are rigid, leading to poor flexibility and adhesion issues on curved surfaces, resulting in reduced heat transfer and mechanical strength, and are difficult to position and reposition without damaging the conductive structures.

Innovation Solution

A planar element with a perforated contacting layer and an intrinsically heatable self-adhesive layer, where the contacting layer is spread out in a surface form with continuous cutouts free of adhesive on the second side surface, allowing for flexible alignment and bonding on both sides without damaging the protective film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a rigid composite tape with conductor surfaces and intrinsically heatable ink is used, then heating function is achieved, but flexibility and adhesion on curved surfaces deteriorate

Engineering Contradiction:
Improveheating functionVSAvoidflexibility on curved surfaces
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The contacting layer is divided into discrete contact regions separated by recesses, allowing the layer to flex and conform to curved surfaces while maintaining electrical contact. The segmented structure enables the heating element to adapt to mirror curvature without compromising the continuous heating function across the surface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heating element uses thin film structures with inherent flexibility that can conform to curved mirror surfaces. The contacting layer with recesses creates a flexible configuration that maintains adhesion on curved substrates while enabling the heating function to operate effectively across the contoured surface.

Inventive Principle:
Principle #30Flexible shells and thin films

2Stability of the object's composition

If a rigid composite tape structure is used, then structural stability is achieved, but adhesion strength on curved substrates deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidadhesion strength on curved surfaces
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The contacting layer is segmented into contact regions and recesses, creating a structure that can flex with curved substrates while maintaining overall structural integrity. This segmentation allows the adhesive to distribute stress more effectively across the curved surface, preventing detachment while preserving structural stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heating element structure transitions from rigid to dynamically adaptable, allowing it to conform to curved surfaces. The recesses in the contacting layer enable dynamic adjustment to substrate curvature, maintaining adhesion strength while preserving structural stability through flexible deformation.

Inventive Principle:
Principle #15Dynamics

3Reliability

If conventional adhesive systems are used, then bonding is achieved, but positioning and repositioning capability deteriorates

Engineering Contradiction:
ImprovebondingVSAvoidpositioning and repositioning capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The heating element is designed with pre-formed contact regions and recesses that facilitate initial positioning on the mirror surface. The recesses allow for alignment adjustment during installation, enabling precise positioning before final bonding occurs, while still achieving reliable adhesion once positioned.

Inventive Principle:
Principle #10Preliminary action

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 provides improved flexibility and adhesion on curved surfaces, enhances heat transfer, and allows for precise positioning and easy detachment without damaging the conductive structures, while maintaining mechanical and electrical contact.

Implementation Method 1

the heating layer consisting of an intrinsically heatable self-adhesive (10), which is designed as a conductor that heats up when an electric current is passed through it

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The heat generated is transferred to the glass surface of the mirror via a double-sided adhesive tape and thus heats it up

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2199063B1Heated area element and method for fixing same
Publication Date: 2017.05.24 TESA SE
  • EP2199063B1 patent drawingFigure 1a~1b
  • EP2199063B1 patent drawingFigure 2a~2b
  • EP2199063B1 patent drawingFigure 3a~3b

AI summary

The flat element comprises a front side and a rear side, which has a heating layer and a contacting layer, where the heating layer consists of an intrinsically heatable self-adhesive mass (10), which is formed as a conductor heating itself during passing an electric current. The contacting layer is formed as a contacting element (20) expanded in a flat-shaped manner and broken by notches and has a first side surface and a second side surface. The contacting layer contacts with the heating layer over the first side surface and is electrically conductively connected with the heating layer. The flat element comprises a front side and a rear side, which has a heating layer and a contacting layer, where the heating layer consists of an intrinsically heatable self-adhesive mass (10), which is formed as a conductor heating itself during passing an electric current. The contacting layer is formed as a contacting element (20) expanded in a flat-shaped manner and broken by notches and has a first side surface and a second side surface. The contacting layer contacts with the heating layer over the first side surface and is electrically conductively connected with the heating layer. The second side surface of the contacting layer forms the front side of the flat element. The notches are continuously formed in the contacting element over the thickness of the contacting element and are present in the area of the second side surface in an adhesive-free manner. The intrinsically heatable self-adhesive mass is a positive temperature coefficient (PTC) thermistor. The first side surface of the contacting layer is partially embedded into the intrinsically heatable self-adhesive mass, and lies on a side surface of the intrinsically heatable self-adhesive mass in a flat manner. The thickness of the contacting element is less than 20 mu m. The notches form more than 50% of the surface of the first side surface of the contacting layer or more than 75% of the first side surface of the contacting layer. The broken contacting element has web-shaped areas, which have a width of highly 5 mm or less than 1 mm and are present in a branched comb structure or finger structure. The intrinsically heatable self-adhesive mass comprises an electrically conducting filler material, which comprises graphite, carbon nanoparticles and conductive soot. An independent claim is included for a method for joining a flat element with an adhesion substrate.