OLED Color Patterning via Sacrificial Lift-Off

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Solution Overview

Problem

The commercialization of high-resolution OLED displays is hindered by low manufacturing yield, high fabrication costs, and reduced display quality due to limitations in current color-patterning technologies, particularly the photolithography method, which causes OLED degradation from UV light exposure and expensive production procedures.

Innovation Solution

A method involving the formation of a protecting layer over the organic light-emitting layer to minimize damage during photolithography, followed by simultaneous removal of the sacrificial and protecting layers to create patterned light-emitting 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 due to UV light exposure and manufacturing cost increases

Engineering Contradiction:

Improvecolor patterning precisionVSAvoidOLED degradation from UV light

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A light-emitting layer is formed as an intermediary between the substrate and the pixel electrodes. This light-emitting layer serves as a mediator that enables color patterning through selective removal (lift-off process) rather than direct UV exposure, thereby protecting the OLED structure from photolithography-induced degradation while maintaining manufacturing precision

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a sacrificial layer that is intentionally designed to be temporary and removable. This sacrificial layer is deposited, patterned, and then completely removed through lift-off process, serving its purpose during fabrication but being discarded in the final product. This approach replaces expensive and damaging photolithography with a simpler, less costly deposition and removal process

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

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

Engineering Contradiction:

Improvepattern definitionVSAvoidfabrication cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the complex photolithography system (requiring UV exposure equipment, photomasks, and chemical development processes) with a simpler physical vapor deposition system followed by a chemical lift-off process. This substitution uses material deposition and selective dissolution instead of optical patterning, significantly reducing equipment costs and fabrication complexity while maintaining pattern definition capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the fundamental parameter of pattern formation from optical absorption (photolithography) to material solubility differences (lift-off process). By selecting materials with different solubility characteristics in specific solvents, the patent achieves pattern definition through chemical dissolution rather than UV exposure, thereby reducing manufacturing costs while preserving precision

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If multiple processing steps are used for color patterning, then pattern quality can be improved, but manufacturing yield decreases

Engineering Contradiction:

Improvepattern qualityVSAvoidmanufacturing yield

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent combines multiple patterning operations into a single unified process. Instead of performing separate photolithography steps for each color layer, the invention deposits all light-emitting layer materials sequentially on a common sacrificial layer, then removes the sacrificial layer in one lift-off operation to pattern all layers simultaneously. This merging of steps reduces process complexity and improves manufacturing yield by minimizing the number of alignment and processing operations required

Inventive Principle:

Principle #5Merging (Combining)

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 the 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.

Implementation Method 1

the first patterned protecting layer is soluble in an etchant and the first patterned light-emitting layer is insoluble or less soluble in the etchant

Methodology Applied

Scientific EffectSelective dissolution:

Data Source

PatentUS11398600B2Method for manufacturing electroluminescent device

Publication Date: 2022.07.26 INT TECH CO LTD

AI summary

A method of manufacturing an electroluminescent device includes forming a first patterned structure in a first pixel through a first opening of a first sacrificial layer; removing the first sacrificial layer; forming a second patterned structure in a second pixel through a second opening of a second sacrificial layer; removing the second sacrificial layer; and removing a first patterned protecting layer from the first patterned structure and a second patterned protecting layer from the second patterned structure to respectively form a first patterned light-emitting layer and a second patterned light-emitting layer.