Segmented Optical Film for Flexible OLED Stress and Color Gamut

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Solution Overview

Problem

Flexible organic light emitting display devices face issues with stress-induced damage at bending areas, leading to peeling of light emitting diode layers and thin film transistor breakage, which deteriorates color gamut and video quality.

Innovation Solution

A complex film structure comprising an adhesive layer with distinct areas for optical and optical conversion films, along with a protective film, is applied to the substrate, where the optical conversion film with quantum-dot particles on the bending area enhances color gamut while facilitating bending without excessive stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If an optical film is formed on the bending area to enhance color gamut, then color purity is improved, but stress on the bending area increases causing peeling and breakage

Engineering Contradiction:
Improvecolor gamutVSAvoidstructural integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The optical film is divided into two distinct areas: a first area with an optical film for high color gamut requirements, and a second area with an optical conversion film for stress reduction. This segmentation allows each area to have optimized properties for its specific function, resolving the contradiction between color quality and structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different optical films are applied to different areas based on local requirements. The first area receives an optical film with high color gamut properties, while the second area receives an optical conversion film with better flexibility and stress resistance, matching the local quality needs of each region.

Inventive Principle:
Principle #3Local quality

2Reliability

If the optical film is removed from the bending area to reduce stress, then structural integrity is improved, but color gamut deteriorates

Engineering Contradiction:
Improvestructural integrityVSAvoidcolor gamut
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

Instead of removing the optical film entirely, the solution segments the film structure into two areas, preserving the optical film in the first area for color gamut maintenance while using an optical conversion film in the second area for stress reduction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The optical film is selectively applied only where high color gamut is critical (first area), while the optical conversion film is applied where stress resistance is more important (second area), optimizing the balance between color quality and structural integrity locally.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If a thick optical film is used to enhance color gamut, then color purity is improved, but bending flexibility decreases

Engineering Contradiction:
Improvecolor purityVSAvoidbending capability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The optical film structure is segmented into two areas with different thickness and material properties. The first area has a thicker optical film for color purity, while the second area has a thinner optical conversion film for bending flexibility, resolving the contradiction between color quality and adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different film thicknesses and materials are used in different areas: the first area uses a thicker optical film where color purity is prioritized, while the second area uses a thinner optical conversion film where bending capability is prioritized, matching local quality requirements.

Inventive Principle:
Principle #3Local quality

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 improves color purity and reduces stress on the bending area, enabling uniform luminance and better bending capabilities, thus enhancing the display's stereoscopic effect and immersion level.

Implementation Method 1

an optical conversion film provided on the second area of the adhesive layer

Methodology Applied
Scientific EffectQuantum-dot light conversion: Photoluminescence

Data Source

PatentEP3477724B1Organic light emitting display device comprising an optical film
Publication Date: 2024.02.14 LG DISPLAY CO LTD
  • EP3477724B1 patent drawingFigure 1~3
  • EP3477724B1 patent drawingFigure 4~5
  • EP3477724B1 patent drawingFigure 6

AI summary

An organic light emitting display device and a complex film included in the organic light emitting display device are disclosed, which facilitates bending on a bending area and has optical characteristics of wide color gamut, whereby a stereoscopic effect may be improved. The organic light emitting display device comprising a substrate (200); and a complex film provided on the substrate, wherein the complex film includes an adhesive layer (110) having a first area (A1) and a second area (A2); an optical film (120) provided on the first area of the adhesive layer; an optical conversion film (130) provided on the second area of the adhesive layer; and a protective film (140) covering the optical film and the optical conversion film.