Low Dielectric Encapsulation Layer for Touch Sensitivity
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Solution Overview
Problem
Conventional display apparatuses with integrated touch screens have high relative permittivity in their encapsulation layers, leading to reduced touch sensitivity due to the inverse proportional relationship between capacitance and touch sensitivity.
Innovation Solution
A display apparatus with an encapsulation layer comprising a first elastic layer, a low dielectric layer with a relative permittivity of 2.5 to 2.8, and a second elastic layer, which reduces the relative permittivity and enhances touch sensitivity by incorporating a low dielectric material like a siloxane copolymer with a molecular sieve structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional encapsulation layer with high relative permittivity (3.4 to 3.6) is used, then the encapsulation layer provides adequate protection and structural integrity, but the touch sensitivity is reduced due to increased capacitance
Solution Approach 1:
The encapsulation layer is divided into multiple sub-layers with different relative permittivity values. The first encapsulation layer has a relative permittivity of 2.5 to 2.8, while the second encapsulation layer has a relative permittivity of 3.0 to 3.3. This segmentation allows the touch-sensitive region to have lower permittivity for improved sensitivity while maintaining overall encapsulation functionality.
Solution Approach 2:
Different regions of the encapsulation layer are assigned different relative permittivity values based on their functional requirements. The first encapsulation layer directly beneath the touch electrode has lower relative permittivity (2.5 to 2.8) to enhance touch sensitivity, while the second encapsulation layer has higher relative permittivity (3.0 to 3.3) to provide adequate protection and structural integrity.
2Reliability
If the encapsulation layer thickness is increased to improve protection, then the structural integrity and protection are enhanced, but the weight increases and flexibility is reduced
Solution Approach 1:
The encapsulation layer is constructed as a composite structure with two different materials having distinct relative permittivity values. The first encapsulation layer uses a material with relative permittivity of 2.5 to 2.8, and the second encapsulation layer uses a material with relative permittivity of 3.0 to 3.3. This composite structure achieves optimal balance between protection, weight, and touch sensitivity.
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 reduced relative permittivity of the encapsulation layer increases touch sensitivity by up to 10% and improves the signal-to-noise ratio, while also allowing for a thinner layer that reduces weight and enhances flexibility, thereby improving the product yield and handling of external impacts.
Implementation Method 1
The relative permittivity of the low dielectric layer is 2.5 to 2.8. The relative permittivity of the encapsulation layer is proportional to a capacitance provided between the light emitting layer and the touch electrode, and a touch sensitivity of the touch electrode is inversely proportional to the square of a capacitance.
Data Source
AI summary
Disclosed is a display apparatus with integrated touch screen, in which a relative permittivity of an encapsulation layer is reduced, thereby increasing touch sensitivity. The display apparatus with integrated touch screen includes a light emitting layer disposed on a lower substrate, an encapsulation layer disposed on the light emitting layer, and a touch electrode disposed on the encapsulation layer. The encapsulation layer includes a first elastic layer disposed on the light emitting layer, a low dielectric layer disposed on the first elastic layer, and a second elastic layer disposed on the low dielectric layer. A relative permittivity of the low dielectric layer is 2.5 to 2.8.