Oval Organic Molecule Encapsulation for Display Touch Sensitivity
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Solution Overview
Problem
Touch sensitivity in display devices, such as smartphones and tablets, can be inconsistent due to variations in capacitance between sensing electrodes, which is influenced by the dielectric constant of materials between them, leading to suboptimal user input recognition.
Innovation Solution
A display device structure incorporating a substrate, electrodes, a bank layer, an emissive layer, an encapsulation layer with a combination of inorganic and organic films, and a touch layer, where the organic film contains oval-shaped organic molecules with specific chemical formulas, optimizing the dielectric properties to enhance touch sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a dielectric material with higher dielectric constant is used between sensing electrode and conductive electrode, then capacitance increases, but touch sensitivity decreases
Solution Approach 1:
The patent changes the dielectric constant parameter of the material between sensing electrode and conductive electrode from high to low (specifically using materials with dielectric constant of 3.0 or less), which directly reduces parasitic capacitance and improves touch sensitivity
Solution Approach 2:
The patent employs a composite encapsulation layer structure combining inorganic films (such as SiO2, Si3N4, SiON) and organic films (such as BCB, polyimide) with controlled dielectric constants, creating a multi-layer composite structure that optimizes both protection and electrical properties to minimize parasitic capacitance
2Reliability
If encapsulation layer thickness is increased to protect electrodes, then electrode protection improves, but parasitic capacitance increases
Solution Approach 1:
The patent optimizes the thickness parameter of the encapsulation layer, using thin-film structures (inorganic films and organic films with controlled thickness) that provide sufficient protection while minimizing the dielectric volume that would contribute to parasitic capacitance
Solution Approach 2:
The patent uses a multi-layer composite encapsulation structure where inorganic films provide mechanical strength and barrier properties with minimal thickness, while organic films fill gaps and provide additional protection, achieving optimal protection-to-capacitance ratio
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 proposed structure reduces parasitic capacitance and enhances touch sensitivity by adjusting the dielectric constant of the organic film, improving the accuracy and reliability of touch input recognition.
Implementation Method 1
The capacitance between two sensing electrodes or between a sensing electrode and an adjacent conductive electrode (e.g., an electrode of a light emitting element) may be affected by the dielectric constant(s) of the dielectric material(s) interposed therebetween
Implementation Method 2
an encapsulation layer disposed on the second electrode
Data Source
AI summary
A display device includes a substrate; a first electrode disposed on the substrate; a bank layer disposed on the substrate and including an opening exposing the first electrode; an emissive layer disposed on the first electrode exposed by the bank layer; a second electrode disposed on the bank layer and the emissive layer; an encapsulation layer disposed on the second electrode; and a touch layer disposed on the encapsulation layer, in which the encapsulation layer includes at least one inorganic film and at least one organic film, and in which the organic film contains organic molecules having an oval shape.