Counter Electrode Leak Current Absorption in OLED Displays

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Solution Overview

Problem

Existing organic electroluminescence (EL) display devices face issues with current leakage between pixel electrodes, causing unintended light emission in adjacent pixels, which complicates the manufacturing process due to the need for additional electrodes and insulating layers.

Innovation Solution

A display device design featuring a substrate with pixel electrodes, carrier injection and transport layers, a light-emitting layer, and a counter electrode, where the carrier transport layers have a connection area between adjacent pixel electrodes, allowing the counter electrode to connect and absorb any leak current, thereby preventing unintended light emission without the need for additional electrodes or insulating layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electrode for absorbing leak current is arranged on a bank, then the phenomenon of adjacent pixels emitting light unexpectedly is restrained, but the manufacturing process becomes complicated due to the need for additional electrodes and insulating layers

Engineering Contradiction:

Improveprevention of unintended light emissionVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the function of the leak current absorbing electrode with the counter electrode itself. The counter electrode is designed to extend into the bank region and directly absorb leak current without requiring a separate dedicated electrode structure. This integration eliminates the need for additional insulating layers between separate electrodes while maintaining the reliability of preventing unintended light emission in adjacent pixels.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The counter electrode performs multiple functions: it serves as the standard counter electrode for the organic EL layer while simultaneously functioning as the leak current absorbing electrode by extending into the bank region. This multi-functionality reduces device complexity by eliminating redundant structures while maintaining the reliability function of preventing color mixing between adjacent pixels.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If both an electrode of a different layer and an insulating layer are provided to absorb leak current, then unintended light emission is prevented, but the manufacturing process is complicated

Engineering Contradiction:

Improvecolor display accuracyVSAvoidmanufacturing process simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the leak current absorbing function with the existing counter electrode structure, eliminating the need for separate insulating layers. The counter electrode material itself provides the necessary electrical isolation and leak current absorption functionality, simplifying the manufacturing process while ensuring accurate color display by preventing electrical interference between adjacent pixels.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The counter electrode serves itself by extending into the bank region to perform the leak current absorption function that would otherwise require separate dedicated structures. This self-service approach allows the same component to fulfill multiple roles, reducing manufacturing complexity while maintaining the reliability needed for accurate color display.

Inventive Principle:

Principle #25Self-service

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 design simplifies the manufacturing process while effectively preventing unintended light emission from adjacent pixels, ensuring accurate color display by controlling carrier movement and eliminating the need for complex electrode arrangements.

Implementation Method 1

a first carrier injection layer and a first carrier transport layer provided in order on the plurality of pixel electrodes; a light-emitting layer provided above the plurality of pixel electrodes and on the first carrier transport layer; a second carrier transport layer and a second carrier injection layer provided in order on the light-emitting layer

Methodology Applied

Scientific EffectCarrier transport: Conduction (electrical)

Implementation Method 2

The organic EL layer includes a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS10784459B2Display device

Publication Date: 2020.09.22 MAGNOLIA WHITE CORP

AI summary

A display device includes: a plurality of pixel electrodes; a first carrier injection layer, a first carrier transport layer, a light-emitting layer, a second carrier transport layer, and a second carrier injection layer provided in order on the plurality of pixel electrodes; and a counter electrode provided on the second carrier injection layer. The second carrier has a polarity opposite to that of the first carrier. The counter electrode is connected to one layer of the first carrier transport layer and the first carrier injection layer, penetrating a layer situated between the one layer and the counter electrode, between the pixel electrodes adjacent to each other in a plan view. Alternatively, an upper surface of an intermediate electrode situated between the pixel electrodes adjacent to each other in a plan view is connected to the first carrier injection layer.