Electroluminescence Display Bank Bleaching for Uniformity

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Solution Overview

Problem

Electroluminescence display devices face issues with non-uniform dopant concentration leading to uneven deterioration and 'burn-in' effects, affecting brightness and contrast, particularly due to sensitivity to moisture and oxygen, and challenges in achieving uniform film deposition on larger substrates.

Innovation Solution

The implementation of a manufacturing method involving bleaching processing with varying intensity across the substrate to correlate with dopant concentration distribution in the light emitting layer, using a positive correlation to adjust the bleaching intensity based on dopant concentration, and incorporating a negative correlation with photoresist material concentration to extend the electroluminescence element's lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If vacuum deposition is used to form the light emitting layer, then uniform film formation is achieved, but non-uniformity occurs when the substrate size increases

Engineering Contradiction:

Improvefilm uniformityVSAvoidsubstrate size

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The patent applies local quality by varying the dopant concentration in different regions of the light emitting layer according to the substrate area. Larger substrates have non-uniform dopant distribution where the concentration varies from the center to the edges, allowing each region to be optimized for its specific size and deposition characteristics, thereby maintaining film uniformity across the entire large substrate area

Inventive Principle:

Principle #3Local quality

2Power

If the dopant concentration is increased to improve light emission efficiency, then the lifetime of the electroluminescence element decreases

Engineering Contradiction:

Improvelight emission efficiencyVSAvoidelement lifetime

Core Design Contradiction:

PowerVSDuration of action of stationary object

Solution Approach 1:

The patent implements local quality by creating a non-uniform dopant concentration distribution where the concentration is lower in regions that would otherwise experience higher stress or degradation. This spatial variation in dopant concentration allows the system to maintain overall light emission efficiency while extending the lifetime by reducing dopant-induced degradation in critical areas

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies parameter changes by varying the dopant concentration as a key parameter across different regions of the light emitting layer. By changing this parameter spatially rather than maintaining a uniform concentration, the system optimizes both light emission efficiency and lifetime, as the dopant concentration is adjusted to balance performance and durability requirements

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the dopant concentration is uniform across the substrate, then all elements deteriorate uniformly, but brightness and contrast are reduced overall

Engineering Contradiction:

Improveuniform deteriorationVSAvoidbrightness and contrast

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent applies local quality by intentionally creating non-uniform dopant concentration distribution across the substrate. Different regions have optimized dopant concentrations that balance uniform deterioration characteristics with maintained brightness and contrast performance, rather than using a single uniform concentration that would compromise overall illumination quality

Inventive Principle:

Principle #3Local quality

4Manufacturing precision

If non-uniform dopant concentration is present, then the degree of deterioration varies across the plane, causing burn-in effects

Engineering Contradiction:

Improvedopant concentration controlVSAvoidburn-in and brightness unevenness

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements local quality by designing a controlled non-uniform dopant concentration distribution that compensates for expected deterioration patterns. The dopant concentration is varied spatially to pre-correct for burn-in effects, ensuring that regions prone to higher degradation have lower initial dopant concentrations, thereby achieving uniform visual performance across the display plane

Inventive Principle:

Principle #3Local quality

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 in-plane non-uniformity of electroluminescence element deterioration, enhancing the display's brightness and contrast stability over time by optimizing dopant and photoresist material distribution, thereby improving the overall performance and longevity of the electroluminescence display device.

Implementation Method 1

a bank that separates the adjacent pixels and has been subjected to bleaching processing

Methodology Applied

Scientific EffectBleaching processing: Photo-oxidation

Data Source

PatentUS10825877B2Electroluminescence display device and manufacturing method thereof

Publication Date: 2020.11.03 MAGNOLIA WHITE CORP

AI summary

Provided is an electroluminescence display device including, on a substrate, a plurality of pixels having a light emitting layer made of an electroluminescent material obtained by adding a dopant to a host material, and a bank that separates the adjacent pixels and has been subjected to bleaching processing, in which within the plane of the substrate, the concentration of the dopant in the light emitting layer is distributed and the intensity of the bleaching processing performed on the bank is distributed.