Display Encapsulation Stack for Touch Stability and Layer Adhesion
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Solution Overview
Problem
Conventional display apparatuses face issues such as separation of organic encapsulation layers from inorganic layers and wrinkling due to low relative permittivity, which degrade touch sensor performance and increase manufacturing defects.
Innovation Solution
A display apparatus with a specific multilayer encapsulation structure comprising a first and second inorganic encapsulation layer with defined densities and compressive stress, and an organic encapsulation layer with a relative permittivity of 2.3 to 2.7, which includes silicon nitride or silicon oxynitride, to enhance durability and prevent layer separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the organic encapsulation layer has low relative permittivity to prevent touch sensor performance degradation, then touch sensor performance is maintained, but layer separation and wrinkles occur
Solution Approach 1:
The patent optimizes the relative permittivity of the organic encapsulation layer to a specific range (2.3 to 2.7) to balance two conflicting requirements: maintaining touch sensor performance by preventing capacitance interference while avoiding layer separation and wrinkles. This parameter optimization resolves the contradiction by finding the optimal value that satisfies both conditions.
Solution Approach 2:
The patent employs a composite encapsulation structure combining organic and inorganic encapsulation layers. The organic encapsulation layer with controlled relative permittivity is integrated with inorganic layers to achieve both touch sensor performance and structural stability, preventing layer separation while maintaining electrical properties.
2Reliability
If the organic encapsulation layer has low relative permittivity to reduce capacitance, then touch sensor performance is preserved, but manufacturing defects increase
Solution Approach 1:
By precisely controlling the relative permittivity parameter of the organic encapsulation layer within the range of 2.3 to 2.7, the patent simultaneously achieves touch sensor performance requirements and minimizes manufacturing defects such as layer separation and wrinkles during the manufacturing process.
3Object-affected harmful factors
If the second inorganic encapsulation layer has high density to improve barrier properties, then oxidation resistance improves, but compressive stress increases causing layer separation
Solution Approach 1:
The patent optimizes the density of the second inorganic encapsulation layer to a specific range (>1.8 g/cm³) and controls its compressive stress (>60 MPa and <180 MPa) to balance oxidation resistance and layer adhesion. This parameter control prevents both oxidation damage and layer separation.
Solution Approach 2:
The patent applies different properties to different layers: the second inorganic encapsulation layer has high density for oxidation resistance, while the organic encapsulation layer has low relative permittivity for touch sensor performance. Each layer is optimized locally to fulfill its specific function without compromising overall 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
The multilayer encapsulation structure significantly reduces manufacturing defects by minimizing layer separation and oxidation, ensuring robust performance of the touch sensor and display element protection.
Implementation Method 1
the organic encapsulation layer has a relative permittivity of 2.3 to 2.7, so as to prevent the performance of a touch sensor from being degraded by a capacitance between the touch sensor and an opposite electrode
Implementation Method 2
the second inorganic encapsulation layer has a density of greater than 1.8 g/cm³, and a compressive stress of greater than 60 MPa and less than 180 MPa, thereby preventing the organic encapsulation layer from being separated from the inorganic encapsulation layer, and reducing an oxidation rate
Data Source
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AI summary
A display apparatus includes a display element on a substrate, and an encapsulation layer covering the display element. The encapsulation layer includes a first inorganic encapsulation layer, a second inorganic encapsulation layer, and an organic encapsulation layer between the first inorganic encapsulation layer and the second inorganic encapsulation layer. The organic encapsulation layer has a relative permittivity of 2.3 to 2.7, and the second inorganic encapsulation layer has a density of greater than 1.8 g/cm3 and less than 2.03 g/cm3.