OLED Repair via Third Electrode Extension

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Solution Overview

Problem

Organic electroluminescent devices face defects such as bright and dark spots due to faulty TFTs, which are difficult to repair, leading to increased production costs and reduced display quality, especially in high-resolution displays where minimal defects are required.

Innovation Solution

The device incorporates a unique electrode structure with a third portion of the first electrode extending to neighboring pixels, allowing for electrical connection and repair of defective pixels by overlapping with the drain electrode of the neighboring driving TFT, enabling normal operation of defective pixels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a pixel with a bright spot defect is repaired by disconnecting the driving TFT, then the bright spot defect is eliminated, but the pixel becomes a dark spot and remains difficult to repair

Engineering Contradiction:
Improvebright spot defectVSAvoidrepairability of dark spot
Core Design Contradiction:
Object-affected harmful factorsVSEase of repair

Solution Approach 1:

The patent applies preliminary action by pre-configuring the first electrode with a third portion that extends into the neighboring pixel region before any defect occurs. This advance preparation enables subsequent repair of dark spot defects by allowing the electrode to be connected to neighboring pixels, thereby resolving the repairability issue without requiring complex post-defect modifications

Inventive Principle:
Principle #10Preliminary action

2Ease of repair

If the first electrode is extended to neighboring pixels, then defective pixels can be repaired by electrical connection, but the device structure becomes more complex

Engineering Contradiction:
Improverepairability of defective pixelsVSAvoidelectrode structure complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The patent implements universality by designing the first electrode's third portion to serve multiple functions: it acts as a standard electrode component during normal operation and simultaneously serves as a repair conduit when defects occur. This multi-functionality enables the same structure to support both normal display operations and defect repair, reducing the need for separate repair mechanisms and thereby limiting complexity increase

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If high-resolution displays with minimal defect tolerance are manufactured, then display quality is improved, but production costs increase due to higher failure rates

Engineering Contradiction:
Improvedisplay qualityVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-configuring the first electrode with a third portion that extends into the neighboring pixel region before any defect occurs. This advance preparation enables subsequent repair of dark spot defects by allowing the electrode to be connected to neighboring pixels, thereby resolving the repairability issue without requiring complex post-defect modifications

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements discarding and recovering by enabling the recovery of previously defective pixels through electrical connection to neighboring pixels. Instead of discarding defective pixels as waste, the system recovers their functionality by rerouting electrical connections, thereby reducing the number of pixels that need to be replaced and lowering production costs

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP2876684B1Organic electroluminescent device and repairing method thereof
Publication Date: 2021.01.13 LG DISPLAY CO LTD
  • EP2876684B1 patent drawingFigure 1
  • EP2876684B1 patent drawingFigure 2
  • EP2876684B1 patent drawingFigure 3~4

AI summary

An organic electroluminescent device (101) includes a substrate (110) including a plurality of pixel regions (P1, P2) each having a light emission region (EA) and an element region (DA); a plurality of thin film transistors (TFTs) including at least one switching TFT (Tr1) and at least one driving TFT (Tr2) in each element region (DA); a planarization layer (150) on the plurality of TFTs; a first electrode (160) on the planarization layer (150) and including first to third portions (160a - c)connected to one another, wherein the first (160a) and second portions (160b) are at each pixel region, and the third portion (160c) is at a neighboring pixel region; an organic light emitting layer (165) on the first electrode (160); and a second electrode (168) on the organic light emitting layer (165), wherein an end of the third portion (160c) overlaps the driving TFT (Tr2) of the neighboring pixel region.