Organic Light Emitting Display Device Layer Thickness Optimization

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Solution Overview

Problem

Existing organic light emitting display devices face challenges in achieving desired color reproduction rates and color stability due to limitations in the structure and material characteristics of the emission layers, leading to inefficiencies in red, green, and blue emission efficiencies and unwanted color changes when viewed from different angles.

Innovation Solution

The organic light emitting display device incorporates a structure with optimized thicknesses of organic layers in its emission parts, including a first, second, and third emission part with specific layer configurations and distances, to reduce color change rates based on viewing angles, thereby improving color reproduction and emission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single emission layer is used to manufacture white organic light emitting device, then manufacturing simplicity is improved, but color reproduction rate and white balance adjustment are worsened

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcolor reproduction rate
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The emission layer is divided into multiple sub-layers (first emission layer, second emission layer, third emission layer) with different emission characteristics. Each sub-layer emits light at different wavelengths or color temperatures, allowing independent optimization of color reproduction while maintaining a relatively simple single-layer structure compared to multi-stack approaches.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If multiple emission layers are stacked to improve color reproduction, then color reproduction rate is improved, but device complexity and manufacturing difficulty are worsened

Engineering Contradiction:
Improvecolor reproduction rateVSAvoidemission layer structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Multiple emission layers are merged into a single integrated emission layer structure with optimized thicknesses. The first, second, and third emission layers are positioned at specific distances from the substrate and from each other, combining their emission characteristics to achieve improved color reproduction without the full complexity of separate multi-stack devices.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If conventional emission layer thicknesses are used, then manufacturing ease is improved, but color change rate based on viewing angle is worsened

Engineering Contradiction:
Improvemanufacturing easeVSAvoidcolor stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The thicknesses of the first, second, and third emission layers are specifically optimized to reduce color change rate based on viewing angle. By adjusting these dimensional parameters, the patent achieves improved color stability across different viewing angles while maintaining manufacturing feasibility through conventional thin-film deposition techniques.

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

This approach results in reduced color change rates and enhanced emission efficiency, minimizing color defects caused by viewing angle changes and providing sharper, more realistic image quality.

Implementation Method 1

An electron and a hole are injected from the two electrodes into the organic emission layer, and an exciton is generated by combining the electron with the hole. The organic light emitting device is a device using the principle that light is emitted when the generated exciton is dropped from an excited state to a ground state.

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3309853B1Organic light emitting display device
Publication Date: 2019.03.13 LG DISPLAY CO LTD
  • EP3309853B1 patent drawingFigure 1
  • EP3309853B1 patent drawingFigure 2~3
  • EP3309853B1 patent drawingFigure 4A~4B

AI summary

Discussed is an organic light emitting display device. The organic light emitting display device according to an embodiment includes a first electrode and a second electrode on a substrate to be opposite to each other and at least three emission parts between the first electrode and the second electrode. A first distance between the substrate and the first emission layer, a second distance between the first emission layer and the second emission layer, a third distance between the second emission layer and the third emission layer, and a fourth distance between the third emission layer and the second electrode are different from each other .