OLED Spacer Layer for High Color Rendering and Efficiency

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Solution Overview

Problem

Conventional organic light-emitting diodes (OLEDs) face challenges in simultaneously achieving high color rendering index (CRI) and power or current efficiency, often resulting in complex and costly production processes.

Innovation Solution

Incorporating a spacer between light-emitting layers in an OLED structure, with the spacer's material selected to control electron and hole combination, allowing for excellent CRI and high power or current efficiency while simplifying the production process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple organic layers and emission layers are used to improve color rendering index, then color rendering index is improved, but device complexity and production cost increase

Engineering Contradiction:

Improvecolor rendering indexVSAvoidstructure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple emission layers into a single integrated structure with a core emission layer and auxiliary emission layers, reducing structural complexity while maintaining high color rendering index through the synergistic effect of multiple emitters in one unified design

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The auxiliary emission layers serve multiple functions: they emit light to improve color rendering index, assist in electron-hole recombination, and control energy transfer to the core emission layer, thereby achieving multiple objectives with added layers rather than increasing complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple organic layers and emission layers are used to improve color rendering index, then color rendering index is improved, but power efficiency deteriorates

Engineering Contradiction:

Improvecolor rendering indexVSAvoidpower efficiency

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent optimizes the energy levels of the auxiliary emission layers to be higher than the core emission layer, controlling the direction of energy transfer and ensuring that energy flows efficiently from auxiliary to core layers, thereby maintaining high power efficiency while improving color rendering

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The auxiliary emission layers continuously assist in electron-hole recombination and transfer energy to the core emission layer, ensuring continuous useful action that maintains high power efficiency while contributing to improved color rendering index

Inventive Principle:

Principle #20Continuity of useful action

3Measurement precision

If multiple organic layers and emission layers are used to improve color rendering index, then color rendering index is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvecolor rendering indexVSAvoidproduction process simplicity

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The emission region is segmented into a core emission layer and auxiliary emission layers with distinct functions, allowing for modular design and simplified manufacturing processes compared to integrating multiple separate emission regions, thereby improving color rendering while maintaining ease of manufacture

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

The OLED achieves ideal power or current efficiency and excellent color rendering index with an uncomplicated structure, capable of replacing traditional fluorescent lamps for illumination purposes.

Implementation Method 1

the light-emitting layer 15 is mainly used to control the combination of the electrons and the holes as well as the light-emission

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

the HOMO and LUMO energy levels of the spacer material locate between those of the adjacent light-emitting layers, and therefore the combination of the holes and the electrons of the organic light-emitting layers can be well controlled to emit light

Methodology Applied

Scientific EffectEnergy level control:

Data Source

PatentUS8564015B2Organic light-emitting diode with high color rendering

Publication Date: 2013.10.22 NATIONAL TSING HUA UNIVERSITY

AI summary

An organic light-emitting diode with high color rendering is provided, which includes: a substrate; a first electrode disposed over the substrate; a light-emitting region disposed over the first electrode, in which the light-emitting region includes a plurality of light-emitting layers and at least one spacer, the spacer being disposed between any two of the light-emitting layers and each of the light-emitting layers individually including a dye; and a second electrode disposed over the light-emitting region. Accordingly, the organic light-emitting diode according to the present invention can exhibit high color rendering and high illumination efficiency.