Transparent Display Encapsulation Dam for Moisture Crack Resistance

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Solution Overview

Problem

Display devices are susceptible to moisture and oxygen penetration through cracks in the encapsulation layer, leading to reduced lifespan and malfunction of light emitting devices.

Innovation Solution

A transparent display device with a dam structure between the substrates, where the end portion of the inorganic layer of the encapsulation layer overlaps the dam, incorporating organic material and particles to absorb moisture and maintain substrate bonding, while reducing the risk of cracks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an encapsulation layer is used to protect light emitting devices, then reliability is improved, but cracks in the encapsulation layer can still occur allowing moisture penetration

Engineering Contradiction:
Improveprotection of light emitting devicesVSAvoidmoisture penetration through cracks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A dam structure is introduced as an intermediary element between the encapsulation layer and the external environment. The dam is positioned at the boundary between the display area and non-display area, creating an additional protective barrier that intercepts moisture before it can reach the light emitting devices through cracks in the encapsulation layer.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The dam structure is formed in advance during the manufacturing process, before the encapsulation layer is applied. By pre-positioning the dam at the boundary area, the design proactively prevents moisture penetration paths before they can compromise the light emitting devices, rather than relying solely on the encapsulation layer to prevent all moisture ingress.

Inventive Principle:
Principle #10Preliminary action

2Area of stationary object

If the encapsulation layer extends to the edge of the substrate, then coverage is improved, but the risk of cracks and moisture penetration increases

Engineering Contradiction:
Improvecoverage area of encapsulation layerVSAvoidcrack resistance
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The protective structure is segmented into two distinct components: the encapsulation layer covering the light emitting devices in the display area, and the dam structure positioned at the boundary in the non-display area. This segmentation allows the encapsulation layer to provide comprehensive coverage without needing to extend to the extreme edges of the substrate, thereby reducing stress concentration and crack formation while maintaining effective protection through the distributed dam barrier.

Inventive Principle:
Principle #1Segmentation

3Reliability

If a dam structure is added to prevent moisture penetration, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvemoisture barrier effectivenessVSAvoidnumber of structural components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The dam structure serves multiple functions simultaneously: it acts as a moisture barrier, provides mechanical support at the boundary between display and non-display areas, and defines the structural boundary of the device. By consolidating these multiple functions into a single structural element, the design achieves improved moisture protection without proportionally increasing overall device complexity.

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

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

Enhances the lifespan of light emitting devices by minimizing moisture penetration and crack formation, reducing manufacturing costs and greenhouse gas emissions, and improving display area efficiency.

Implementation Method 1

an end portion of the inorganic layer of the encapsulation layer is overlapped with the dam

Methodology Applied
Scientific EffectPhysical barrier (overlapping structure):

Implementation Method 2

incorporating organic material and particles to absorb moisture

Methodology Applied
Scientific EffectMoisture absorption: Absorption (physical)

Data Source

PatentEP4580376A1Transparent display device
Publication Date: 2025.07.02 LG DISPLAY CO LTD
  • EP4580376A1 patent drawingFigure 1~2
  • EP4580376A1 patent drawingFigure 3~4
  • EP4580376A1 patent drawingFigure 5

AI summary

A transparent display device (100) includes a first substrate (111) and a second substrate (112) facing each other; a plurality of light emitting devices (ED) is disposed on one surface of the first substrate (111), a display area (DA) having an emission area in which the plurality of light emitting devices (ED) are disposed and a transmissive area (TA) for transmitting external light, a non-display area (NDA) disposed outside the display area (DA), an encapsulation layer (130) disposed on the plurality of light emitting devices (ED) to cover the plurality of light emitting devices (ED) and including an inorganic layer (131), and a dam (200) disposed between the first substrate (111) and the second substrate (112) in the non-display area, wherein an end portion of the inorganic layer (131) of the encapsulation layer (130) is overlapped with the dam (200).