Thin Film Encapsulation Layer UV Reflection Structure

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Solution Overview

Problem

Organic light emitting display devices are vulnerable to damage from ultraviolet and near ultraviolet rays, which can lead to moisture permeation and oxygen exposure, affecting their longevity and performance.

Innovation Solution

A thin film encapsulation layer with a specific stacking structure of three films, including a low refractive index layer with a refractive index of 1.7 or greater and a high refractive index layer with a refractive index of 2.3 or greater, is used to reflect ultraviolet and near ultraviolet rays, protecting the organic light emitting layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thin film encapsulation layer is provided to protect organic light emitting elements from moisture and oxygen, then the reliability of the device is improved, but the device becomes vulnerable to ultraviolet and near ultraviolet ray damage

Engineering Contradiction:

Improveprotection from moisture and oxygenVSAvoidultraviolet and near ultraviolet ray damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The encapsulation layer uses a composite structure with multiple thin films having different refractive indices. The first thin film has a refractive index of 1.7 or greater, the second thin film has a refractive index of 2.3 or greater, creating a composite material system that provides both moisture barrier protection and ultraviolet ray reflection capabilities

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different regions of the encapsulation layer are assigned different refractive index properties. The first thin film region provides one level of protection while the second thin film region provides enhanced ultraviolet reflection. This local differentiation of optical properties allows the structure to address multiple harmful factors simultaneously

Inventive Principle:

Principle #3Local quality

2Duration of action of stationary object

If a thin film encapsulation layer is used to protect from moisture and oxygen, then device longevity is improved, but ultraviolet ray permeation affects the organic light emitting layer

Engineering Contradiction:

Improvedevice longevityVSAvoidultraviolet ray permeation

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The dual-layer thin film structure with distinct refractive indices creates a composite barrier that simultaneously provides long-term moisture protection and ultraviolet ray reflection, extending device longevity without compromising against ultraviolet damage

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

By changing the refractive index parameter of the thin films (first film: 1.7 or greater, second film: 2.3 or greater), the encapsulation layer achieves optimized performance for both moisture barrier durability and ultraviolet ray reflection, ensuring long-term device operation

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If a thin film encapsulation layer with specific refractive index layers is used to reflect ultraviolet rays, then protection from ultraviolet damage is improved, but the structural complexity increases

Engineering Contradiction:

Improveultraviolet ray reflectionVSAvoidthin film stacking structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The ultraviolet reflection function is extracted and implemented by a specific second thin film layer with refractive index of 2.3 or greater, while the first thin film layer with refractive index of 1.7 or greater provides the moisture barrier function. This separation of functions reduces overall structural complexity compared to a single multi-functional layer

Inventive Principle:

Principle #2Taking out (Extraction)

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 effectively blocks ultraviolet and near ultraviolet rays, enhancing the stability and longevity of the organic light emitting display device by preventing moisture and oxygen exposure, while maintaining minimal impact on visible light transmission.

Implementation Method 1

a thin film encapsulation layer which includes an ultraviolet ray reflective layer for protecting an organic light emitting layer from ultraviolet rays and near ultraviolet rays

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

a refractive index of the second thin film is about 1.7 or greater, and a refractive index of the first thin film and a refractive index of the third thin film are greater than the refractive index of the second thin film by at least about 0.35 or greater

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS10312473B2Organic light emitting display device

Publication Date: 2019.06.04 SAMSUNG DISPLAY CO LTD

AI summary

An organic light emitting display device includes: a substrate; an organic light emitting element on the substrate; and a thin film encapsulation layer on the organic light emitting element. The thin film encapsulation layer includes a first thin film, a second thin film and a third thin film which are sequentially stacked therein, a refractive index of the second thin film is about 1.7 or greater, and a refractive index of the first thin film and a refractive index of the third thin film are greater than the refractive index of the second thin film by about 0.35 or greater.