Patterned Polarization Layer for Moisture-Resistant Rollable Displays

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Solution Overview

Problem

Existing rollable display devices face issues with warpage and cracks in the display panel due to moisture absorption by the polarization plate, which affects the device's reliability and display quality.

Innovation Solution

The implementation of a display device design that includes a polarization plate with a patterned polarization layer, where the active area has a first pattern and the non-active area has a second pattern spaced apart by protection layers, and the use of a barrier film to surround the side portions of the display panel and polarization plate to minimize moisture permeation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional polarization plate is used without patterning, then the display device has simple structure and easy manufacture, but the polarization plate absorbs moisture causing warpage and cracks in the display panel

Engineering Contradiction:
Improvedisplay panel integrityVSAvoidpolarization layer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The polarization layer is divided into multiple segments corresponding to different display regions (active area and non-active area). Each segment is independently patterned to control moisture absorption characteristics, preventing uniform warpage across the entire polarization plate while maintaining structural integrity of the display panel.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the polarization layer are given different patterns and properties tailored to their specific functions. The active area region has one pattern configuration while the non-active area has another, allowing each region to optimally handle moisture stress locally without compromising the overall display panel structure.

Inventive Principle:
Principle #3Local quality

2Reliability

If the polarization layer is patterned to reduce moisture absorption, then moisture permeation is minimized and warpage is suppressed, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvemoisture resistanceVSAvoidpolarization layer fabrication
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The polarization layer patterning is segmented according to display regions, allowing standardized manufacturing processes to be applied to each segment type. This modular approach to patterning reduces overall manufacturing complexity compared to creating entirely unique patterns, while still achieving effective moisture resistance through regional optimization.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the polarization layer is patterned with spaced regions, then moisture absorption is delayed and warpage is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvewarpage controlVSAvoidpattern alignment
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The polarization layer is segmented into distinct regions with clear boundaries between active and non-active areas. This segmentation creates well-defined alignment references that simplify the patterning process and reduce the precision requirements compared to creating complex continuous patterns, while effectively controlling warpage through the spaced regional structure.

Inventive Principle:
Principle #1Segmentation

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 effectively delays moisture absorption, suppresses warpage of the display panel, and prevents cracks in the substrate, thereby enhancing the reliability and display quality of the rollable display device.

Implementation Method 1

a barrier film to surround the side portions of the display panel and polarization plate to minimize moisture permeation

Methodology Applied
Scientific EffectPermeation barrier: Diffusion Barrier

Implementation Method 2

The polarization layer includes a first pattern corresponding to the active area and a second pattern spaced apart from the first pattern and corresponding to the non-active area

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3945362B1Display device
Publication Date: 2025.05.21 LG DISPLAY CO LTD
  • EP3945362B1 patent drawingFigure 1A
  • EP3945362B1 patent drawingFigure 1B
  • EP3945362B1 patent drawingFigure 2

AI summary

The display device includes a display panel including an active area and a non-active area; and a polarization plate on the display panel and including a polarization layer. The polarization layer includes a first pattern corresponding to the active area and a second pattern spaced apart from the first pattern and corresponding to the non-active area. Thus, it is possible to delay moisture absorption of a polarization layer.