Stretchable Display Pixel Structure With Prismatic Protection Layers

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Solution Overview

Problem

Existing stretchable display devices face challenges in maintaining image quality and preventing damage to light emitting diodes (LEDs) when repeatedly stretched, while also struggling with light extraction efficiency and misalignment of LEDs.

Innovation Solution

The display device incorporates a stretchable lower substrate with first and second substrates, where pixels are disposed on the first substrates and connected by connection lines on the second substrates. A protection layer with triangular cross-section patterns is applied over the pixels to enhance durability and light extraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protection layer with triangular cross-section patterns is applied over the pixels, then light extraction efficiency is improved and LEDs are protected from damage during stretching, but device complexity increases due to the additional structured layer

Engineering Contradiction:
Improvestretching reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The protection layer employs a triangular cross-section pattern (prismatic structure) instead of a flat surface. This curved/geometric structure serves multiple functions: it protects LEDs from mechanical damage during stretching while simultaneously enhancing light extraction efficiency through the prismatic optical effect, thus resolving the contradiction between reliability improvement and device complexity

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The triangular protection layer structure performs multiple functions simultaneously: mechanical protection of LEDs during stretching, light extraction enhancement, and potential alignment guidance. By combining these functions into a single structural element, the invention improves reliability without adding separate components that would increase device complexity

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

2Illumination intensity

If the protection layer includes triangular cross-section patterns, then light extraction efficiency is enhanced to increase luminance, but manufacturing precision requirements increase due to the complex pattern formation

Engineering Contradiction:
ImproveluminanceVSAvoidmanufacturing precision
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The triangular cross-section pattern creates prismatic structures that efficiently extract light through geometric optics. The specific triangular geometry is optimized to balance light extraction performance with manufacturability, achieving high luminance while maintaining feasible manufacturing precision requirements

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Strength

If connection lines are disposed on second substrates connecting first substrates, then stress on substrates during stretching is reduced, but device complexity increases due to the multi-substrate configuration

Engineering Contradiction:
Improvesubstrate strengthVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The display device is divided into multiple substrates (first substrates for pixels, second substrates for connection lines) rather than using a single continuous substrate. This segmentation allows the connection lines to be isolated on separate substrates, reducing stress concentration on the pixel substrates during stretching while maintaining overall structural integrity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second substrates act as intermediary elements that carry connection lines between first substrates. This intermediary structure protects the connection lines from direct stress during stretching while maintaining electrical connectivity, thus improving substrate strength without creating a monolithic complex structure

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration improves stretching reliability by protecting LEDs from damage, enhances light extraction efficiency to increase luminance, and aids in precise alignment of LEDs during the transfer process, thereby improving yield.

Implementation Method 1

a protection layer disposed on each of the plurality of pixels, wherein the protection layer includes a plurality of patterns each having a triangular cross-section

Methodology Applied
Scientific EffectLight extraction: Refraction

Data Source

PatentEP4002457B1Display device
Publication Date: 2025.02.26 LG DISPLAY CO LTD
  • EP4002457B1 patent drawingFigure 1
  • EP4002457B1 patent drawingFigure 2
  • EP4002457B1 patent drawingFigure 3

AI summary

According to an aspect of the present disclosure, the display device includes: a stretchable lower substrate and a plurality of first substrates disposed on the lower substrate. The display device also includes a plurality of second substrates connecting first substrates adjacent to each other among the plurality of first substrates. The display device further includes a plurality of pixels disposed on the plurality of first substrates. The display device also includes a plurality of connection lines disposed on the plurality of second substrates and connecting the plurality of pixels. The display device further includes a protection layer disposed on each of the plurality of pixels.