Transparent Cover Display Assembly With Uniform Optical Bonding

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Solution Overview

Problem

Existing display arrangements with pixel matrix displays under transparent covers face issues of reflection due to air layers, leading to mechanical decoupling and potential damage from forces, as well as non-uniform adhesive layers.

Innovation Solution

A method involving a support frame and a thermoplastic elastomer to secure the cover, followed by a transparent adhesive layer that ensures a cohesive and uniform attachment of the pixel matrix display, preventing mechanical damage and reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If an adhesive layer is used to couple the display surface to the cover, then reflections are reduced due to matched refractive indices, but mechanical decoupling is lost and the pixel matrix display becomes vulnerable to mechanical damage

Engineering Contradiction:
ImprovereflectionsVSAvoidmechanical protection
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The coupling system is divided into two functional layers: a first adhesive layer in contact with the pixel matrix display providing mechanical cushioning, and a second adhesive layer between the cover and display surface providing optical matching. This segmentation allows each layer to specialize in one function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first adhesive layer acts as an intermediary between the rigid cover assembly and the fragile pixel matrix display, absorbing mechanical shocks and preventing direct force transmission while the second adhesive layer provides the optical interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If liquid adhesive is used for coupling, then optical matching is achieved, but uneven adhesive layer formation occurs due to adhesive loss

Engineering Contradiction:
ImprovereflectionsVSAvoidadhesive layer uniformity
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The support frame is pre-assembled with the cover to create an enclosed cavity before applying the liquid adhesive. This preliminary structuring prevents adhesive loss during application and ensures the adhesive remains contained within the defined space, guaranteeing uniform layer formation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The support frame acts as an intermediary container that holds the liquid adhesive in a controlled manner, preventing it from spreading uncontrollably and ensuring even distribution between the cover and display surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If the display surface is coupled directly to the cover, then mechanical strength is improved, but irreversible damage occurs when force is applied to the cover

Engineering Contradiction:
Improvemechanical couplingVSAvoidmechanical damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The first adhesive layer is applied beforehand between the pixel matrix display and the support frame structure, creating a cushioning layer that absorbs and dissipates mechanical forces before they can reach the display, preventing damage while maintaining coupling.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The adhesive layers change the mechanical parameter of the coupling system from rigid direct contact to compliant bonded connection, allowing the system to deform elastically under load and return to original position, preventing permanent damage.

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

This solution provides a reflection-free optical coupling with a robust and uniform adhesive layer, minimizing mechanical stress on the pixel matrix display and ensuring reliable attachment.

Implementation Method 1

Subsequent solidification of the thermoplastic elastomer secures the support frame to the cover through a material-to-material bond

Methodology Applied
Scientific EffectSolidification: Freezing

Implementation Method 2

a transparent, curing liquid adhesive, forming an adhesive layer

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Data Source

PatentEP4126597B1A display assembly with transparent cover and pixel matrix display fixed thereto in an improved manner, and associated mounting method
Publication Date: 2024.05.29 PREH GMBH
  • EP4126597B1 patent drawingFigure 1
  • EP4126597B1 patent drawingFigure 2
  • EP4126597B1 patent drawingFigure 3

AI summary

The invention relates to a display assembly (1), having: a cover (2) which is transparent at least in some regions; a support frame (5) which is designed to fix the display assembly (1) to a supporting structure, in particular to a motor vehicle body; a pixel matrix display (3) which has a display surface (4); an optional housing (8); wherein the support frame (5) is adjacent to the cover (2), and an interstice (6) is formed which is delimited by the support frame (5) and the cover (2) and is filled with a thermoplastic elastomer in order to fix the support frame (5) on the cover (2); wherein the cover (2) and the support frame (5) form a well (15) in which the pixel matrix display (3) is accommodated; wherein a transparent adhesive layer (7) is formed in the well (15) between the display surface (4) and the cover (2) in order to fix the pixel matrix display (3) on the cover (2), wherein the display surface (4) is visible through the cover (2) and the adhesive layer (7); wherein the optional housing (8) fits over the pixel matrix display (3) and is fixed to the support frame (5).