Organic Dielectric Layer Reduces Capacitance in Display Sensing
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Solution Overview
Problem
The sensitivity of input-sensing parts in display devices, particularly those with organic light-emitting elements, is affected by the electrical capacitance between the electrodes, which can be high due to the encapsulation layers, leading to reduced performance and potential color mixing from light emission.
Innovation Solution
Incorporating an organic dielectric layer with a lower dielectric constant than the encapsulation layer, along with a light-blocking layer, to reduce the electrical capacitance and prevent color mixing, while maintaining effective encapsulation and light blocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an encapsulation layer with organic thin film is used to cover the light-emitting element, then protection and encapsulation are improved, but electrical capacitance between electrodes increases leading to reduced input-sensing part sensitivity
Solution Approach 1:
An organic dielectric layer with low dielectric constant (≤2.7 F/m) is introduced as an intermediary between the encapsulation layer and the input-sensing part. This intermediate layer reduces the electrical capacitance between the electrode of the light-emitting element and the conductive pattern of the input-sensing part, thereby improving sensitivity while maintaining the protective function of the encapsulation layer
Solution Approach 2:
The dielectric constant of the layer between the encapsulation layer and input-sensing part is changed to a lower value (≤2.7 F/m). By changing this physical parameter, the electrical capacitance is reduced, which directly improves the sensitivity of the input-sensing part while maintaining effective encapsulation
2Measurement precision
If the organic dielectric layer has lower dielectric constant to reduce capacitance, then input-sensing sensitivity is improved, but the layer thickness and material selection become more constrained
Solution Approach 1:
The dielectric constant parameter is changed to ≤2.7 F/m to reduce capacitance and improve sensitivity. This parameter change provides a clear design guideline for material selection, narrowing down to materials with specific dielectric properties while maintaining the functional requirements
3Reliability
If encapsulation layer thickness is increased to improve protection, then reliability is improved, but color mixing from light emission increases
Solution Approach 1:
The organic dielectric layer serves as an intermediary that blocks light transmission from the light-emitting element to the input-sensing part. This intermediate layer prevents color mixing while allowing the encapsulation layer to maintain its protective function with appropriate thickness
Solution Approach 2:
The organic dielectric layer is positioned specifically between the encapsulation layer and the input-sensing part, providing localized light blocking functionality. This local placement addresses the color mixing issue without requiring increased thickness of the entire encapsulation structure
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 enhances the sensitivity of the input-sensing part by decreasing electrical capacitance and reduces color mixing, improving the overall performance and durability of the display device, especially in foldable or rollable formats.
Implementation Method 1
The organic dielectric layer may have a dielectric constant smaller than a dielectric constant of the organic thin film, and the dielectric constant of the organic dielectric layer may be equal to or less than about 2.7 farads per meter (F/m)
Data Source
AI summary
A display device includes a light-emitting element, an encapsulation layer covering the light-emitting element and including an organic thin film, an organic dielectric layer on the encapsulation layer and an input-sensing part on the organic dielectric layer. The organic dielectric layer includes an organic material and has a thickness smaller than a thickness of the organic layer of the encapsulation layer.