Pixel Electrode Functional Layer Thickness Gradient
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In display devices, the patterning of light-emitting layers over pixel electrodes can lead to deviations, causing current concentration at the electrode ends and potential deterioration, as seen in Patent Literature 1.
Innovation Solution
A display device with a functional layer between the pixel electrode and counter electrode, where the layer has a thicker first portion overlapping the electrode end and a thinner second portion overlapping the middle, formed through a photosensitive composition process to prevent current concentration and electrode deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the second light-emitting layer is patterned over the patterned first light-emitting layer, then the display device can be manufactured with multiple light-emitting layers, but the portion of the second light-emitting layer that is to overlap the end of the first pixel electrode deviates, causing current concentration and potential deterioration
Solution Approach 1:
The patent applies preliminary action by forming a thick first light-emitting layer portion at the end region of the pixel electrode before forming the second light-emitting layer. This pre-formed thick portion serves as a buffer that compensates for any subsequent alignment deviations, ensuring that the electrode end is always adequately covered even if the second layer shifts during the manufacturing process.
Solution Approach 2:
The patent utilizes parameter changes by varying the thickness of the first light-emitting layer across different regions of the pixel electrode. The thickness is increased at the end region compared to the center region, creating a thickness gradient that provides enhanced coverage and current distribution control at the electrode ends where deviation issues are most critical.
2Ease of manufacture
If the light-emitting layer is uniformly thin across the pixel electrode, then the manufacturing process is simpler, but the end of the pixel electrode cannot be properly covered, causing current concentration
Solution Approach 1:
The patent applies local quality by creating different thickness characteristics of the light-emitting layer at different locations on the pixel electrode. The end regions have a thicker first light-emitting layer portion while the center region has a thinner configuration, optimizing both coverage at critical edges and overall device performance.
Solution Approach 2:
The thick first light-emitting layer portion is formed in advance at the electrode end regions before the second light-emitting layer is applied. This preliminary thick layer ensures adequate coverage and current distribution at the electrode ends, preventing current concentration issues that would otherwise occur with uniform thin layers.
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
The solution effectively prevents current concentration and electrode deterioration, maintaining emission area and luminance by ensuring proper coverage and structure of the pixel electrodes.
Implementation Method 1
subjecting the photosensitive composition layer to exposure and development, to form the functional layer
Data Source
AI summary
A display device includes: a pixel electrode; a counter electrode provided over the pixel electrode; and a functional layer provided between the pixel electrode and the counter electrode. The functional layer has a first portion overlapping an end of the pixel electrode, and a second portion overlapping a middle of the pixel electrode. The first portion is thicker than the second portion.