Electroluminescent Display Electrode Contact Layout for Uniform Emission
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Solution Overview
Problem
The vacuum thermal evaporation process for forming light-emitting layers in electroluminescent display devices is costly and poses challenges for large-sized and high-definition displays due to manufacturing variations and mask sagging, leading to non-uniform brightness and increased production costs.
Innovation Solution
The electroluminescent display device incorporates a substrate with a first electrode, connection pattern, banks, and auxiliary banks with reversely inclined side surfaces, along with a light-emitting layer comprising a hole auxiliary layer and electron auxiliary layer, allowing the second electrode to contact the connection pattern directly through holes, thereby improving electrical contact and reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vacuum thermal evaporation process with fine metal mask is used to form light-emitting layers, then manufacturing precision of light-emitting layers is improved, but device complexity and manufacturing cost increase due to mask preparation and handling
Solution Approach 1:
The patent removes the fine metal mask from the manufacturing process entirely, extracting the problematic component that causes complexity and cost issues while maintaining manufacturing precision through alternative deposition methods
Solution Approach 2:
The patent replaces the mechanical mask-based deposition system with a chemical or solution-based deposition process, eliminating the need for physical masks and their associated handling complexities
2Area of stationary object
If vacuum thermal evaporation process is used for large-sized displays, then light-emitting layers can be formed, but manufacturing variations and mask sagging occur leading to reduced manufacturing precision
Solution Approach 1:
The patent extracts the mask component from the process, eliminating mask sagging issues that plague large-sized display manufacturing while enabling uniform light-emitting layer formation across larger areas
Solution Approach 2:
The patent changes the deposition method from vacuum thermal evaporation to a solution-based process, altering the physical and chemical parameters of the manufacturing process to achieve better uniformity across large display areas
3Reliability
If conventional bank structure is used, then electrode coverage is achieved, but contact resistance increases due to indirect contact between second electrode and connection pattern
Solution Approach 1:
The patent performs preliminary action by forming the auxiliary bank with a reversely inclined side surface before depositing the light-emitting layer, creating a pre-formed pathway that enables direct contact between the second electrode and connection pattern, thereby reducing contact resistance and energy loss
Data Source
AI summary
An electroluminescent display device includes a substrate; a first electrode on the substrate; a connection pattern on the substrate, the connection pattern comprising a same material as the first electrode; a bank covering edges of the first electrode and the connection pattern; an auxiliary bank on the bank corresponding to the connection pattern; a light-emitting layer on the first electrode; and a second electrode on the light-emitting layer, the bank, and the auxiliary bank, wherein the auxiliary bank has a reversely inclined side surface, and wherein the light-emitting layer includes a hole auxiliary layer, a light-emitting material layer, and an electron auxiliary layer, the electron auxiliary layer has an opening exposing the connection pattern, and the second electrode contacts the connection pattern through the hole.