OLED EL Layer Patterning With Sacrificial Films for High Resolution

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Solution Overview

Problem

Existing display technologies face challenges in achieving high resolution, high display quality, high contrast, and high reliability, with conventional methods struggling to form EL layers accurately without deviations and reducing non-light-emitting areas.

Innovation Solution

A method involving the formation of EL layers using a metal maskless process, where sacrificial films are etched to expose pixel electrodes, allowing for separate deposition of EL layers, and a common electrode is formed, enabling precise alignment and reduced non-light-emitting regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional methods are used to form EL layers, then the manufacturing process is simpler, but the alignment accuracy deteriorates and deviations occur

Engineering Contradiction:

Improvealignment accuracy of EL layersVSAvoidcomplexity of manufacturing process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by forming sacrificial films (first sacrificial film and second sacrificial film) before depositing the EL layers. These sacrificial films serve as temporary structures that guide the precise formation of EL layers over different pixel electrodes. The sacrificial films are removed after EL layer formation, having fulfilled their guiding purpose. This preliminary structuring enables high alignment accuracy without requiring complex real-time alignment mechanisms.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If metal mask process is used, then the alignment is easier, but the non-light-emitting areas increase and resolution decreases

Engineering Contradiction:

ImproveresolutionVSAvoidnon-light-emitting areas

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The patent extracts and removes the sacrificial films after they have served their purpose in guiding EL layer formation. By removing these temporary sacrificial structures, the method eliminates the need for permanent metal masks and their associated non-light-emitting areas. This extraction principle allows the light-emitting areas to extend closer together, reducing dead spaces and improving resolution.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The sacrificial films function as disposable temporary structures that are formed, used for alignment guidance, and then removed. This approach replaces the need for expensive and permanent metal masks, allowing for more flexible and precise EL layer formation that maximizes light-emitting areas while minimizing non-light-emitting regions.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Manufacturing precision

If higher resolution is achieved, then the display quality improves, but the manufacturing difficulty increases

Engineering Contradiction:

ImproveresolutionVSAvoidmanufacturing difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent segments the EL layer formation process into distinct stages using separate sacrificial films for different pixel types (e.g., first sacrificial film for red pixels, second sacrificial film for green pixels). This segmentation allows each EL layer to be formed independently with precise control, enabling high resolution displays while maintaining manageable manufacturing complexity through systematic process breakdown.

Inventive Principle:

Principle #1Segmentation

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 approach enables display devices with high resolution, high aperture ratio, and high contrast, achieving resolutions up to 5000 ppi without the need for pseudo pixel arrangements, while ensuring high yield and reliability.

Implementation Method 1

a fourth step of exposing the second pixel electrode by etching the first sacrificial film and the first EL film

Methodology Applied

Scientific EffectEtching:

Implementation Method 2

a second step of depositing a first EL film over the first pixel electrode and the second pixel electrode

Methodology Applied

Scientific EffectVapor deposition: Physical Vapour Deposition

Data Source

PatentUS12588358B2Display device and method for manufacturing display device

Publication Date: 2026.03.24 SEMICON ENERGY LAB CO LTD

AI summary

A method for manufacturing a display device that can easily achieve higher resolution is provided. A display device having both high display quality and high resolution is provided. A first EL film is deposited over a first pixel electrode, a first sacrificial film is formed to cover the first EL film and a first electrode, and the first sacrificial film and the first EL film are etched, so that a first EL layer is formed over the first pixel electrode. Then, the first sacrificial film is removed to expose the first electrode. Furthermore, a common electrode is formed over the first EL layer and the first electrode. The first EL film is etched by dry etching, and the first sacrificial film is removed by wet etching.