OLED Pixel Defining Layer Trap for Foreign Substance

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Solution Overview

Problem

Conventional organic light emitting display devices often experience short-circuiting between the anode and cathode due to foreign substances lodged at the boundary of the pixel defining layer, leading to dark pixels, as existing cleaning methods fail to effectively remove these substances.

Innovation Solution

A pixel defining layer with a trap disposed on the periphery of the pixel electrode is used to trap foreign substances, preventing them from causing short-circuits between the anode and cathode, thereby reducing the likelihood of dark pixel formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cleaning methods are used to remove foreign substances, then the cleaning process is simple and fast, but foreign substances remain lodged at the boundary of the pixel defining layer causing short-circuits

Engineering Contradiction:

Improveprevention of short-circuit between anode and cathodeVSAvoidstructure of pixel defining layer

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The pixel defining layer is segmented into multiple functional regions: a main body portion defining the pixel opening, and protruding portions extending toward the pixel electrode. This segmentation creates distinct zones for different functions - the main body for pixel definition and the protruding portions for trapping foreign substances, thereby resolving the contradiction between maintaining simple structure and improving reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The protruding portions of the pixel defining layer act as intermediary structures between the pixel opening and the pixel electrode. These intermediaries capture foreign substances before they can reach critical interfaces, preventing short-circuits while maintaining the overall simplicity of the device structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the pixel defining layer boundary is simplified, then manufacturing is easier, but foreign substances lodge at the boundary causing dark pixels

Engineering Contradiction:

Improveprevention of dark pixel formationVSAvoidfabrication of pixel defining layer

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The pixel defining layer is divided into a main body portion and protruding portions. This segmentation allows the protruding portions to specifically address foreign substance trapping without complicating the overall manufacturing process, as they can be formed using standard photolithography and etching techniques.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The protruding portions are formed in advance during the pixel defining layer fabrication process, creating pre-positioned traps for foreign substances. This preliminary action prevents foreign substances from causing defects during subsequent assembly and operation, without requiring additional manufacturing steps.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8018141B2Organic light emitting display device with trap for foreign substance and method of fabricating the same

Publication Date: 2011.09.13 SAMSUNG DISPLAY CO LTD

AI summary

An organic light emitting display device having a structure for trapping a foreign substance and a method of fabricating the same. The organic light emitting display device includes a substrate and a pixel electrode disposed on the substrate. A pixel defining layer has an opening for exposing a portion of the pixel electrode, and a trap disposed on at least one side of a periphery of the pixel electrode. An organic functional layer is disposed on the exposed portion of the pixel electrode and includes at least an emission layer. A counter electrode is disposed on the organic functional layer.