Organic EL Pixel Electrode Insulating Layer Aperture Ratio
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Solution Overview
Problem
Existing light emitting devices face challenges in enhancing the aperture ratio while preventing deterioration of specific color light emitting elements due to the limitations of passivation and flattening insulating layers, which can lead to reduced display quality and color drift.
Innovation Solution
A light emitting device configuration where the insulating layer covers more than 50% of the circumferential end portion of one pixel electrode and less than 50% of another, optimizing the exposure of pixel electrodes to prevent intense electric current flow in thinner film regions and enhance the aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating layer covers the end portions of the positive electrode, then electrical insulation between adjacent positive electrodes is improved, but the aperture ratio is limited
Solution Approach 1:
The insulating layer is selectively positioned to cover only specific regions: the inter-electrode spacing regions between adjacent positive electrodes are covered for insulation, while the end portions of the positive electrodes remain uncovered to maintain large aperture ratio. This local differentiation resolves the contradiction between insulation requirements and aperture maximization.
2Area of stationary object
If the insulating layer does not cover the end portions of the positive electrode, then aperture ratio is enhanced, but the functional layer becomes thinner near the end portions causing intensive current flow and element deterioration
Solution Approach 1:
The insulating layer serves as an intermediary element that is strategically placed to cover only the inter-electrode spacing regions, providing electrical insulation without interfering with the functional layer thickness at the positive electrode end portions. This allows both high aperture ratio and element durability to be achieved simultaneously.
3Ease of manufacture
If the functional layer becomes thinner near the end portions of the positive electrode, then manufacturing is simplified, but electric current flows intensively in the thinned-film portion causing element deterioration and color drift
Solution Approach 1:
The insulating layer is extracted or removed from covering the end portions of the positive electrodes, allowing the functional layer to maintain uniform thickness in these critical regions. This prevents intensive current flow and element deterioration while still allowing simplified manufacturing in other areas.
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 configuration effectively suppresses the deterioration of specific color light emitting elements, enhances the aperture ratio, and improves display quality with reduced color drift, achieving higher luminance and resolution.
Implementation Method 1
an insulating layer that is disposed between the first surface and the functional layer via the first and second pixel electrodes
Data Source
AI summary
An organic EL device as a light emitting device includes: a first light emitting element that is disposed on a first surface of a substrate and that has a first pixel electrode; a second light emitting element that has a second pixel electrode; and an insulating layer that is provided with a first opening which exposes the first pixel electrode and a second opening which exposes the second pixel electrode. Further, in the organic EL device, the first opening is configured so that the insulating layer covers equal to or more than 50% of the circumferential edge portion of the first pixel electrode, and the second opening is configured so that the insulating layer covers less than 50% of the circumferential edge portion of the second pixel electrode.