Electroluminescent Display Mesh Electrodes for Low-Parasitic Touch Sensing
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Solution Overview
Problem
Existing electroluminescent displays face issues with parasitic capacitance between the touch sensor and the cathode electrode, which affects touch performance and flexibility, and the encapsulation unit is prone to damage from external forces, leading to operational failures.
Innovation Solution
A flexible electroluminescent display design with a thin encapsulation unit and mesh electrode layers that minimize parasitic capacitance and enhance flexibility, featuring a first and second mesh electrode layer with specific disconnection patterns to optimize touch performance and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the encapsulation unit thickness is reduced to improve flexibility and thin profile, then flexibility and thinness are improved, but parasitic capacitance between the touch sensor and cathode electrode increases
Solution Approach 1:
The encapsulation unit is divided into multiple thin encapsulation layers (first encapsulation layer, second encapsulation layer, third encapsulation layer) rather than using a single thick encapsulation unit. This segmentation reduces the overall thickness while maintaining protective function, thereby improving flexibility and reducing parasitic capacitance between the touch sensor and cathode electrode.
Solution Approach 2:
The patent introduces a new dimensional approach by stacking multiple encapsulation layers in the thickness direction (z-axis) rather than using a single thick layer. This multi-layer structure in the vertical dimension achieves both thinness and flexibility while controlling parasitic capacitance through reduced distance between conductive elements.
2Object-affected harmful factors
If the encapsulation unit thickness is reduced to enhance flexibility characteristics, then flexibility is improved, but the encapsulation unit becomes more susceptible to damage from external forces
Solution Approach 1:
The encapsulation unit employs composite material structure with multiple encapsulation layers made of different materials (organic and inorganic materials) stacked together. This composite structure provides both flexibility and enhanced durability by distributing mechanical stress across multiple layers, preventing crack propagation that would occur in a single thin layer.
Solution Approach 2:
The multi-layer encapsulation structure provides beforehand cushioning against external forces by distributing impact energy across multiple interfaces between layers. The different material properties of each layer absorb and dissipate mechanical stress, protecting the underlying electroluminescent element from damage.
3Measurement precision
If the distance between the touch sensor and cathode electrode is reduced to improve touch sensitivity, then touch sensitivity is improved, but parasitic capacitance increases and may render touch operation impossible
Solution Approach 1:
The encapsulation structure is segmented into multiple thin layers, which reduces the overall distance between the touch sensor and cathode electrode while controlling parasitic capacitance. The segmented structure allows optimized spacing at each interface, achieving high touch sensitivity without excessive parasitic capacitance accumulation.
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 design reduces parasitic capacitance, enhances flexibility and touch sensitivity, and improves manufacturing efficiency while maintaining a thin profile, enabling a foldable electroluminescent display.
Implementation Method 1
an electroluminescent layer positioned on the anode electrode
Implementation Method 2
a first mesh electrode layer positioned on the flexible encapsulation unit and configured to generate a first capacitance together with the cathode electrode
Implementation Method 3
an encapsulation unit disposed on the electroluminescent element
Data Source
AI summary
An electroluminescent display is disclosed. The electroluminescent display includes an electroluminescent element disposed in a display area of a substrate, an encapsulation unit disposed on the electroluminescent element, a first mesh electrode layer disposed on the encapsulation unit, an insulating layer covering the first mesh electrode layer, and a second mesh electrode layer disposed on the insulating layer. The first mesh electrode layer includes a first mesh electrode and a second mesh electrode separated from the first mesh electrode. The second mesh electrode layer includes a third mesh electrode extended in a first direction and a fourth mesh electrode extended in a second direction intersecting the first direction through the first mesh electrode intersecting the third mesh electrode.