Organic EL Display Panel With High Resistance Interlayer
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Solution Overview
Problem
In organic electroluminescence (EL) display panels, leak currents between pixels cause slight light emission of unintended primary colors, leading to color mixture and image quality deterioration.
Innovation Solution
An organic EL display panel design featuring a substrate with pixel electrodes, first organic functional layers spaced apart, and a second organic functional layer with higher electric resistance that covers the first layers and extends into the space between them, blocking currents and preventing unwanted light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a laminate-type white light-emitting layer is used that is common to multiple pixels, then device complexity is reduced and manufacturing is simplified, but leak current occurs between adjacent pixels causing color mixture and image quality deterioration
Solution Approach 1:
The organic functional layers are segmented into first organic functional layers corresponding to each pixel electrode and a second organic functional layer that continuously covers the first layers. This segmentation allows the first layers to be electrically isolated per pixel while the second layer provides continuous coverage, preventing leak current between pixels while maintaining structural efficiency
Solution Approach 2:
The second organic functional layer acts as an intermediary that bridges the gap between adjacent first organic functional layers. By having the second layer extend into the absence region between first layers, it provides electrical isolation and prevents current leakage while maintaining the common light-emitting structure
2Adaptability or versatility
If pixel regions for different primary colors are placed adjacent to each other at the display surface, then color coverage is improved, but leak current causes unintended light emission and color bleeding
Solution Approach 1:
The first organic functional layers are configured with local quality differences - each layer corresponds to a specific pixel electrode and emits a specific primary color. The second organic functional layer provides uniform coverage across all first layers, creating localized emission regions separated by the absence region, thus preventing color bleeding while maintaining full color coverage
Solution Approach 2:
The structure transitions from a two-dimensional arrangement of adjacent pixel regions to a three-dimensional layered structure. The first organic functional layers are positioned at different vertical levels corresponding to each pixel electrode, with the second layer providing overhead coverage. This vertical dimensionality separation prevents lateral current leakage between adjacent color regions
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 design effectively reduces leak currents and prevents image quality deterioration by ensuring only intended colors are emitted, resulting in high-quality display images.
Implementation Method 1
the second organic functional layer has greater electric resistance than each of the first organic functional layers and has a portion extending into an absence region, the absence region being a space between adjacent ones of the first organic functional layers
Data Source
AI summary
An organic EL display panel including: a substrate; pixel electrodes that are arrayed in a matrix above the substrate; first organic functional layers that are on or above the pixel electrodes in one-to-one correspondence with the pixel electrodes, the first organic functional layers spaced apart from one another; a second organic functional layer that continuously covers the first organic functional layers; and a counter electrode that opposes the pixel electrodes and covers the second organic functional layer. In the organic EL display panel, the first organic functional layers each include a hole injection layer, and the second organic functional layer has greater electric resistance than each of the first organic functional layers and has a portion extending into an absence region, the absence region being a space between adjacent ones of the first organic functional layers.