Electroluminescent Display Contact Hole Layout for Uniform Emission
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Solution Overview
Problem
Existing electroluminescent display devices face challenges in forming a uniform emission layer due to step differences caused by contact holes, leading to non-uniform light emission in the emission areas.
Innovation Solution
The electroluminescent display device is designed with a configuration where the emission areas are defined by banks that cover the contact holes, allowing for the formation of sub-emission layers with predetermined intervals, minimizing step differences and ensuring uniform profiles of the emission layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact holes are provided in the insulating layer to connect the first electrode with the driving thin film transistor, then electrical connection is achieved, but step differences are generated on the upper surface of the first electrode causing non-uniform emission layer formation
Solution Approach 1:
The emission area is divided into first and second sub-emission areas separated by the contact hole region. This segmentation allows the contact hole to be positioned between functional emission regions rather than within them, enabling electrical connection while preserving emission layer uniformity in each sub-area.
Solution Approach 2:
The contact hole is extracted from the emission area and repositioned in the non-emission area between sub-emission regions. This extraction removes the source of step differences from the emission zones, allowing uniform emission layer formation while maintaining necessary electrical connections through the contact hole.
2Manufacturing precision
If the emission area is positioned to avoid overlapping with contact holes, then uniform emission layer formation is achieved, but the device layout becomes more complex requiring multiple circuit device columns
Solution Approach 1:
The layout is reorganized from a single-column arrangement to a multi-column configuration where circuit devices are distributed across multiple columns between power lines. This dimensional change in layout strategy provides flexibility to position contact holes in non-emission areas while maintaining emission area integrity, resolving the conflict between uniformity and complexity.
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 enables uniform light emission across the emission areas by preventing the formation of step differences, resulting in consistent and efficient light output.
Implementation Method 1
The emission layer emits light when an exciton is produced by a bond of an electron and a hole, and the exciton falls to a ground state from an excited state
Data Source
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AI summary
Disclosed is an electroluminescent display device comprising a substrate, a circuit device layer provided on the substrate and including a first contact hole, a first electrode provided on the circuit device layer, a bank provided on the first electrode and configured to define a first emission area comprising a first sub emission area for exposing a first portion of the first electrode, and a second sub emission area for exposing a second portion of the first electrode, a first sub emission layer provided in the first sub emission area, and a second sub emission layer provided in the second sub emission area, wherein an area between the first sub emission area and the second sub emission area is overlapped with the first contact hole of the circuit device layer. According to one embodiment of the present invention, a step difference caused by the contact hole is not generated in the emission area so that it is possible to realize a desired profile in the emission layer of the emission area, thereby realizing a uniform light emission in the emission area.