Auxiliary Electrodes for OLED Voltage Drop Reduction

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Solution Overview

Problem

Large-sized top-emission type organic light emitting display apparatuses face non-uniformity in image quality due to significant voltage drop in the second electrode caused by its high resistivity, leading to inconsistent display characteristics.

Innovation Solution

The introduction of lower and upper auxiliary electrodes, disposed in a line shape and perpendicular to each other, which contact the second electrode to reduce voltage drop and ensure uniform voltage distribution across the substrate, thereby enhancing image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the second electrode is formed with high resistivity transparent material and thin thickness to increase light transmittance, then light transmittance is improved, but voltage drop increases

Engineering Contradiction:

Improvelight transmittanceVSAvoidvoltage drop

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The second electrode system is segmented into the original second electrode and multiple auxiliary electrodes (lower and upper) distributed across the substrate. This segmentation allows the main second electrode to remain thin and transparent for light transmission, while auxiliary electrodes compensate for voltage drop by creating additional electrical pathways.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Auxiliary electrodes serve as intermediary elements between the first electrode and the second electrode. These intermediaries provide additional electrical connection points that reduce the overall resistance and voltage drop in the transparent second electrode material.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Illumination intensity

If the second electrode uses high resistivity material to maintain transparency, then light transmittance is improved, but image quality uniformity deteriorates

Engineering Contradiction:

Improvelight transmittanceVSAvoidimage quality uniformity

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The electrode system is divided into multiple components (second electrode and auxiliary electrodes) that work together. The segmented auxiliary electrodes are strategically positioned to ensure uniform voltage distribution across different regions of the display, compensating for the high resistivity of the transparent second electrode material.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the electrode system have different properties: the second electrode maintains high transparency with thin thickness, while auxiliary electrodes provide localized electrical reinforcement in specific areas to ensure uniform voltage distribution and image quality across the entire display surface.

Inventive Principle:

Principle #3Local quality

3Illumination intensity

If the second electrode is made thin to increase light transmittance, then light transmittance is improved, but voltage drop intensifies

Engineering Contradiction:

Improvelight transmittanceVSAvoidvoltage drop

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The electrode system is segmented into the thin second electrode for light transmission and multiple auxiliary electrodes for electrical compensation. This segmentation allows the second electrode to be optimized for transparency while auxiliary electrodes compensate for the resulting voltage drop.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The solution extends from a single-plane electrode structure to a multi-dimensional electrode system by adding lower auxiliary electrodes (below the organic layer) and upper auxiliary electrodes (above the second electrode). This dimensional expansion provides multiple electrical pathways that reduce voltage drop while maintaining the thinness of the light-transmitting second electrode.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 auxiliary electrodes effectively minimize voltage drop and ensure consistent voltage distribution, improving the uniformity and quality of the display by electrically connecting the second electrode to the auxiliary electrodes, thus addressing the issue of resistivity-induced non-uniformity.

Implementation Method 1

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9379360B2Organic light emitting display apparatus including lower and upper auxiliary electrodes

Publication Date: 2016.06.28 SAMSUNG DISPLAY CO LTD

AI summary

An organic light emitting display apparatus includes a plurality of first electrodes disposed in each of a plurality of pixels on a substrate, a plurality of lower auxiliary electrodes insulated from the first electrodes and in which the lower auxiliary electrodes are disposed in a first direction, an organic layer disposed on the first electrodes, and a second electrode facing the first electrodes and covering the organic layer. The second electrode is disposed on substantially an entire surface of the substrate. The organic light emitting display apparatus further includes a plurality of upper auxiliary electrodes disposed on the second electrode in a second direction.