OLED Conductive Black Layer Suppresses Reflection

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Solution Overview

Problem

The polarizing plate in organic light emitting diode (OLED) displays absorbs light, leading to reduced luminance and deteriorated display quality due to reflection issues.

Innovation Solution

The use of a conductive black layer with silver sulfide (Ag2S) and a light reflective first conductive layer with a magnesium silver alloy (MgAg) or aluminum (Al) in the OLED structure, which absorbs light and reduces reflection, improving luminance and display quality without the need for a polarizing plate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a polarizing plate is used to suppress light reflection, then reflection is reduced, but luminance deteriorates due to light absorption

Engineering Contradiction:

Improvelight reflectionVSAvoidluminance

Core Design Contradiction:

Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The invention removes the polarizing plate from the OLED display structure entirely. Instead of using a polarizing plate to suppress reflection, the patent employs a reflective electrode design where the electrode itself reflects light back through the organic emission layer, eliminating the need for additional light-absorbing components like polarizing plates.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than absorbing reflected light as the polarizing plate does, the invention inverts the approach by reflecting light back through the emission layer. The electrode is designed to reflect light, and the organic emission layer is configured to emit light in response to this reflected light, converting the harmful reflection into a useful light source.

Inventive Principle:

Principle #13The other way round (Inversion)

2Object-affected harmful factors

If a conductive black layer with silver sulfide is used to absorb light, then reflection is suppressed, but manufacturing complexity increases

Engineering Contradiction:

Improvelight reflectionVSAvoidmanufacturing process

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The invention combines the reflective function and the electrode function into a single integrated structure. The electrode is designed with specific reflective properties and is positioned to face the organic emission layer, eliminating the need for separate conductive black layers or additional light-absorbing components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The electrode serves multiple functions: it provides electrical conduction, reflects light back through the emission layer, and acts as one of the boundaries for the organic emission layer. This multi-functional design simplifies the overall structure and reduces manufacturing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Illumination intensity

If a light reflective first conductive layer is used to maintain luminance, then luminous efficiency improves, but device complexity increases

Engineering Contradiction:

ImproveluminanceVSAvoidelectrode structure

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The reflective function is merged into the electrode structure itself. The first conductive layer is designed with reflective properties and is positioned to face the organic emission layer, combining the electrical conduction function and the light reflection function in a single integrated component.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The electrode is segmented into multiple layers with specific functions: the first conductive layer provides reflection and faces the organic emission layer, while the second conductive layer provides electrical conduction. This segmentation allows each layer to be optimized for its specific function while maintaining overall simplicity.

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 configuration enhances luminous efficiency and suppresses reflection, resulting in improved display quality by ensuring most light is absorbed or transmitted effectively, reducing visible reflections and maintaining high luminance.

Implementation Method 1

the conductive black layer is formed by heat treating the second conductive layer under a sulfur (S) atmosphere

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

the conductive black layer is formed by heat treating the second conductive layer under a sulfur (S) atmosphere

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

the first conductive layer is light reflective

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 4

an organic light emitting diode for displaying an image by emitting light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS8698169B2Organic light emitting diode display

Publication Date: 2014.04.15 SAMSUNG DISPLAY CO LTD

AI summary

An organic light emitting diode (OLED) display includes a first electrode including a conductive black layer, a second electrode facing the first electrode, and an organic emission layer provided between the first electrode and the second electrode.