Viscoelastic Layer Backlight for Uniform Illumination

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Solution Overview

Problem

Conventional backlight assemblies for electronic display devices are complex, requiring separate components and materials for optical coupling, which increases manufacturing costs and reduces durability.

Innovation Solution

A backlight composite assembly integrating a light source optically coupled to a lightguide with a viscoelastic layer and a nanovoided polymeric layer, featuring interconnected nanovoids and structured surfaces for efficient light management and distribution, eliminating the need for additional adhesive layers and simplifying fabrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional backlight assemblies use separate components and materials for optical coupling, then optical functionality is achieved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvebacklight assembly structureVSAvoidassembly durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent combines the adhesive layer and optical coupling functions into a single integrated layer. The viscoelastic material serves dual purposes as both adhesive and optical coupling medium, eliminating the need for separate adhesive and optical coupling components. This merging reduces the number of interfaces and potential failure points while simplifying the overall assembly structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The viscoelastic layer performs multiple functions simultaneously: it provides adhesive bonding between components, enables optical coupling for light transmission, and offers stress relief through its viscoelastic properties. This multi-functionality reduces the need for specialized separate components and simplifies the backlight assembly design.

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

2Ease of manufacture

If multiple separate layers (adhesive, optical films) are used in backlight assembly, then optical functionality is achieved, but manufacturing cost increases

Engineering Contradiction:
Improvefabrication simplicityVSAvoidnumber of components
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the adhesive layer and optical coupling layer into a single viscoelastic layer, reducing the total number of components from multiple separate layers to one integrated layer. This simplification directly reduces manufacturing complexity and material costs while maintaining all necessary functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The viscoelastic layer is designed to perform multiple functions simultaneously - adhesive bonding, optical coupling, and stress management - eliminating the need for separate specialized components and reducing overall device complexity.

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

3Reliability

If conventional adhesive layers are used without viscoelastic properties, then assembly is simplified, but stress relief and durability are reduced

Engineering Contradiction:
Improveassembly durabilityVSAvoidmaterial properties requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the material parameter from conventional rigid or semi-rigid adhesive to viscoelastic material. This parameter change enables the adhesive to exhibit time-dependent mechanical behavior, providing stress relief and strain accommodation while maintaining bond strength, thereby improving durability without adding complexity.

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

The solution provides a cost-effective, durable, and adaptable illumination device that can be used in various applications, offering bright, diffuse, and uniform light with improved light extraction efficiency and flexibility, suitable for both interior and exterior use.

Implementation Method 1

a light source optically coupled to a lightguide such that light emitted by the light source enters the lightguide and is transported within the lightguide by total internal reflection

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a nanovoided polymeric layer comprising a plurality of interconnected nanovoids at least some of the interconnected nanovoids being connected to one another by hollow passages

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 3

the nanovoided polymeric layer comprising a plurality of interconnected nanovoids

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 4

a viscoelastic layer and a nanovoided polymeric layer

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP2534509B1Illumination device having viscoelastic layer
Publication Date: 2019.07.24 3M INNOVATIVE PROPERTIES CO
  • EP2534509B1 patent drawingFigure 1~2b
  • EP2534509B1 patent drawingFigure 3a~4b
  • EP2534509B1 patent drawingFigure 4c~5b

AI summary

An illumination device, such as a backlight for electronic display devices, is disclosed. The illumination device includes a lightguide optically coupled to a light source, and a viscoelastic layer and a nanovoided polymeric layer are used in conjunction with the lightguide to manage light emitted by the light source. The viscoelastic layer may be a pressure sensitive adhesive.