OLED Pixel Dummy Pattern Layout for Etchant Residue Removal

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Solution Overview

Problem

Existing display device manufacturing processes face challenges in ensuring complete removal of etchant residues during the formation of organic light emitting elements, leading to potential defects and failures such as icicle or fence shape formations that can affect light emission and electrode connectivity.

Innovation Solution

Incorporating a dummy pattern in the non-emission region between pixels, which extends along the direction of one pixel, to guide and remove etchant residues effectively, thereby preventing defects like icicle or fence shape formations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If etchant is used to remove sacrificial layer in non-emission region, then sacrificial layer removal is achieved, but etchant residues remain causing defects

Engineering Contradiction:

Improvesacrificial layer removal completenessVSAvoidetchant residues

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A dummy pattern is introduced as an intermediary structure in the non-emission region. This dummy pattern serves as a mediator that facilitates complete etchant removal by providing a pathway or collection area for etchant residues, preventing them from contaminating the emission region and causing defects like icicle or fence shape formations.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The dummy pattern converts the potentially harmful accumulation of etchant residues into a beneficial outcome. By deliberately providing a designated area (the dummy pattern) where etchant residues can accumulate, the harmful effect of residue accumulation is redirected away from the critical emission region, thereby preventing defects while maintaining manufacturing efficiency.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If dummy pattern is added in non-emission region, then etchant residue removal is improved, but device structure becomes more complex

Engineering Contradiction:

Improvedefect reductionVSAvoidpattern structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The dummy pattern is localized exclusively to the non-emission region, leaving the emission region and its critical structures unchanged. This local modification approach improves reliability by addressing etchant residue issues only where they occur, without adding complexity to the functional light-emitting portions of the device.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The dummy pattern acts as a disposable or sacrificial structure that serves its purpose during manufacturing (collecting/removing etchant residues) and then becomes part of the final encapsulated structure. It performs its function temporarily during the manufacturing process and is subsequently covered by encapsulation layers, effectively making it a temporary solution that resolves itself.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If dummy pattern extends along pixel direction, then etchant flow guidance is improved, but manufacturing process becomes more complex

Engineering Contradiction:

Improveetchant flow controlVSAvoidpattern geometry

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The dummy pattern is segmented to extend along the pixel direction in the non-emission region, creating a directional structure that guides etchant flow. This segmentation approach divides the non-emission region into zones that control etchant movement, improving flow guidance without requiring complex three-dimensional structures or multiple patterning steps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of trying to prevent etchant accumulation through complex barrier structures, the invention inverts the approach by deliberately creating a dummy pattern that channels and collects etchant residues in a controlled manner. This inverted thinking simplifies the manufacturing process by working with the etchant flow rather than against it.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS12075685B2Display device and manufacturing method thereof

Publication Date: 2024.08.27 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a substrate with a display region and a non-display region. The display region includes first pixels, second pixels, and third pixels. Each of the first to third pixels have emission regions from which light is to be emitted, a light emitting element in the emission region, and a pixel circuit area to drive the light emitting element. A dummy pattern extends through a non-emission region of the substrate located in the display region between adjacent pixels. A thin film encapsulation layer covers the dummy pattern and each of the emission regions.