OLED Encapsulation with Refractive Index Gradient

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Solution Overview

Problem

Existing OLED display devices face challenges in reducing the thickness of encapsulation layers, which affects the viewing angle and display effect, while also being susceptible to environmental factors that can degrade the color filter over time.

Innovation Solution

A light-emitting device is designed with a silicon-based base substrate, an organic light-emitting diode (OLED) device, a first encapsulation layer with a higher refractive index, a color filter layer, and a second encapsulation layer with a lower refractive index, where the second encapsulation layer includes high-molecular polymer molecules for precise thickness control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the thickness of encapsulation layers is reduced to improve viewing angle and display effect, then the viewing angle and display effect are improved, but the color filter becomes susceptible to environmental degradation

Engineering Contradiction:
Improveviewing angleVSAvoidcolor filter protection
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The encapsulation structure is divided into multiple functional layers: a first encapsulation layer (inorganic material) directly protecting the OLED device, a color filter layer, and a second encapsulation layer (organic material) protecting the color filter. This segmentation allows each layer to perform its specific function optimally while maintaining overall device protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a composite encapsulation structure combining inorganic and organic materials. The inorganic first encapsulation layer provides barrier protection against moisture and oxygen, while the organic second encapsulation layer provides additional protection and flexibility. This composite approach achieves both thin profile and reliable color filter protection.

Inventive Principle:
Principle #40Composite materials

2Device complexity

If a single-layer encapsulation structure is used to simplify device structure, then device complexity is reduced, but the ability to simultaneously protect OLED and color filter while controlling thickness is compromised

Engineering Contradiction:
Improveencapsulation structureVSAvoidthickness control
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The encapsulation system is segmented into distinct layers with specific functions: the first encapsulation layer (inorganic) provides barrier protection for the OLED, while the second encapsulation layer (organic) protects the color filter. This segmentation enables independent optimization of each layer's thickness and material properties.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes refractive index differences between layers to optimize optical performance. By carefully selecting materials with appropriate refractive indices for each layer, the structure achieves enhanced light extraction and viewing angle improvement while maintaining precise thickness control for each functional layer.

Inventive Principle:
Principle #35Parameter changes

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 reduces the overall thickness of the light-emitting device, increases the viewing angle, and protects the color filter from environmental degradation, thereby prolonging the service life of the OLED display.

Implementation Method 1

a refractive index of at least one sublayer in the first encapsulation layer is greater than a refractive index of at least one sublayer in the second encapsulation layer

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP4024492B1Light-emitting device
Publication Date: 2025.04.09 BOE TECHNOLOGY GROUP CO LTD
  • EP4024492B1 patent drawingFigure 1~2
  • EP4024492B1 patent drawingFigure 3~4
  • EP4024492B1 patent drawingFigure 5~6

AI summary

A light-emitting device, a method of manufacturing the same and an electronic apparatus. The light-emitting device includes a silicon-based base substrate; at least one organic light-emitting diode device at the silicon-based base substrate; a first encapsulation layer, at a side of the at least one organic light-emitting diode device away from the silicon-based base substrate and including one or more sublayers; a color filter layer, at a side of the first encapsulation layer away from the at least one organic light-emitting diode device; and a second encapsulation layer, at a side of the color filter layer away from the first encapsulation layer and including one or more sublayers. A refractive index of at least one sublayer in the first encapsulation layer is greater than a refractive index of at least one sublayer in the second encapsulation layer. The light-emitting device can prevent the color film from aging and losing efficacy due to exposure to the external environment, thereby prolonging the service life of the light-emitting device.