Pressure-Sensitive Adhesive for Light Diffusion and Gap Elimination

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current light source structures, such as back light units, face issues with light loss due to air gaps between light sources and diffuser plates, and materials like PMMA or PC curl easily under high temperature and humidity, leading to optical property degradation and manufacturing challenges.

Innovation Solution

A pressure-sensitive adhesive composition is developed, comprising specific weight ratios of (meth)acrylic acid ester monomers, (meth)acrylic acid, and other compounds, along with scattering particles and dyes, to form a photocurable or thermosetting adhesive that minimizes light loss by eliminating air gaps and maintaining optical properties under varying conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a diffuser plate is simply placed above a light source with an air gap, then the structure is simple and easy to manufacture, but light loss occurs due to the air gap

Engineering Contradiction:
Improvelight lossVSAvoidstructure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines the diffuser plate and adhesive layer into a single integrated component. The diffuser plate is directly bonded to the light source or light guide plate without an air gap, eliminating light loss while maintaining manufacturing simplicity. This merging of functions (diffusion + bonding) resolves the contradiction between reducing light loss and avoiding increased device complexity.

Inventive Principle:
Principle #5Merging (Combining)

2Illumination intensity

If surface treatment is given to the light guide plate to provide diffusion function, then light diffusion is improved, but process efficiency is greatly decreased

Engineering Contradiction:
Improvelight diffusionVSAvoidprocess efficiency
Core Design Contradiction:
Illumination intensityVSProductivity

Solution Approach 1:

The patent extracts the diffusion function from the light guide plate and relocates it to a separate diffuser plate. This allows the light guide plate to maintain its original simple structure for efficient manufacturing, while the diffuser plate provides the required light diffusion performance. The diffusion function is separated and implemented in a dedicated component, resolving the contradiction between light diffusion and process efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

3Loss of energy

If matching oil is used to remove the air gap, then light loss is reduced, but liquid leakage occurs due to heat of the light source

Engineering Contradiction:
Improvelight lossVSAvoidliquid leakage
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent replaces the matching oil (which leaks and requires maintenance) with a solid adhesive layer that is heat-resistant and reliable. The adhesive is cured to form a stable, permanent bond that eliminates the air gap without the leakage problems of liquid matching oil. This substitution of a reliable solid material for a problematic liquid material resolves the contradiction between reducing light loss and preventing liquid leakage.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Illumination intensity

If hard-type materials like PMMA or PC are used for the diffuser plate, then optical properties are good, but the material curls easily under high temperature and humidity conditions

Engineering Contradiction:
Improveoptical propertiesVSAvoiddimensional stability
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent uses a composite material structure for the diffuser plate, combining polymer base resin with inorganic fillers or additives that provide heat and humidity resistance. This composite formulation maintains the optical properties needed for light diffusion while adding dimensional stability to prevent curling under severe environmental conditions. The composite material integrates the benefits of both organic (optical) and inorganic (stability) properties.

Inventive Principle:
Principle #40Composite materials

5Ease of manufacture

If plastic materials are used for the diffuser plate, then manufacturing is easy, but moisture and solvents are released as gas causing bubbles and optical degradation

Engineering Contradiction:
Improvemanufacturing easeVSAvoidoptical property degradation
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the material composition parameters of the diffuser plate by selecting polymers with low out-gassing characteristics and appropriate molecular weight distributions. The material formulation is optimized to minimize moisture and solvent release during operation, preventing bubble formation and optical degradation while maintaining ease of manufacturing through conventional processing methods. Parameter optimization of material composition resolves the contradiction between manufacturing ease and reliability.

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 adhesive composition effectively reduces light loss, prevents curling and optical property degradation, and ensures durability and stability in high temperature and humidity environments, making it suitable for flexible device applications and maintaining excellent optical performance.

Implementation Method 1

the adhesive composition for an optical device, which can prevent out-gassing

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

a pressure-sensitive adhesive composition... to form a photocurable or thermosetting adhesive that minimizes light loss by eliminating air gaps

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

along with scattering particles and dyes, to form a photocurable or thermosetting adhesive

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP2639275B1Pressure-sensitive adhesive composition
Publication Date: 2023.10.18 LG CHEM LTD
  • EP2639275B1 patent drawingFigure 1~3
  • EP2639275B1 patent drawingFigure 4~5
  • EP2639275B1 patent drawing

AI summary

Provided is a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition may be applied as a light diffusing or scattering material to various display devices or lighting apparatuses.