OLED Color Patterning via Sacrificial Layer Removal

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Solution Overview

Problem

The commercialization of high-resolution OLED displays is limited by low manufacturing yield, high fabrication costs, and low display quality due to constraints in current color-patterning technologies, particularly the photolithography method, which causes OLED degradation and high costs associated with UV light exposure and expensive photomask production.

Innovation Solution

The method involves forming protecting layers over organic light-emitting layers to minimize damage during photolithography, followed by a single-step removal of sacrificial layers and protecting layers, simplifying the fabrication process and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photolithography method is used for color patterning, then manufacturing precision can be achieved, but OLED degradation occurs and fabrication cost increases

Engineering Contradiction:

Improvecolor patterning precisionVSAvoidOLED degradation from UV light exposure

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A sacrificial layer is introduced as an intermediary component between the substrate and the light-emitting layers. This sacrificial layer serves as a temporary structure that enables precise color patterning during fabrication, then is completely removed after serving its purpose, leaving no harmful residues on the OLED structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The fabrication process is segmented into distinct phases: first forming light-emitting layers over entire pixel regions, then using a separate sacrificial layer removal step to define final color patterns. This segmentation allows photolithography to be used for precise patterning without permanently exposing the OLED to harmful UV effects in the final structure.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If photolithography method is used for color patterning, then manufacturing precision can be achieved, but fabrication cost increases

Engineering Contradiction:

Improvecolor patterning precisionVSAvoidfabrication cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The sacrificial layer acts as a temporary copy or placeholder structure that replicates the desired final pattern during fabrication. This allows the use of standard photolithography techniques for precise patterning, while the actual light-emitting materials are deposited in simpler, more cost-effective processes without requiring expensive color-specific photomasks for each layer.

Inventive Principle:

Principle #26Copying

3Manufacturing precision

If multiple separate removal steps are used for sacrificial layers and protecting layers, then manufacturing precision is maintained, but process complexity increases

Engineering Contradiction:

Improvepattern definition accuracyVSAvoidfabrication process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The sacrificial layer and protecting layer are designed to be removed together in a single etching step. The etchant is selected to simultaneously etch both layers without damaging the underlying light-emitting materials, thereby reducing the number of fabrication steps while maintaining precise pattern definition.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The protecting layer serves multiple functions: it protects the light-emitting layer during fabrication and is simultaneously designed to be removed with the sacrificial layer. This multi-functionality reduces process complexity by eliminating the need for separate removal steps for each layer type.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 reduces damage to organic light-emitting layers, lowers manufacturing costs, and enables the production of high-resolution electroluminescent devices in a cost-effective manner by simplifying the fabrication procedures and minimizing process complexity.

Implementation Method 1

removing the first sacrificial layer together with the second sacrificial layer

Methodology Applied

Scientific EffectChemical dissolution:

Implementation Method 2

removing the first protecting layer from the first light-emitting layer, and the second protecting layer from the second light-emitting layer

Methodology Applied

Scientific EffectChemical etching:

Data Source

PatentUS11171318B2Method for manufacturing electroluminescent device with sacrificial layer

Publication Date: 2021.11.09 INT TECH CO LTD

AI summary

A method of manufacturing an electroluminescent device includes providing a substrate including a first pixel and a second pixel configured to emit different colors; forming a first light-emitting layer and a first protecting layer over the substrate through a first opening of a first sacrificial layer; forming a second light-emitting layer and a second protecting layer over the substrate through a second opening of a second sacrificial layer; removing the first sacrificial layer together with the second sacrificial layer; and removing the first protecting layer from the first light-emitting layer, and the second protecting layer from the second light-emitting layer.