Display Encapsulation Structure for Touch Stability and Wrinkle Prevention
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Solution Overview
Problem
Conventional display apparatuses face issues such as separation of organic encapsulation layers and wrinkling due to low relative permittivity, which degrade touch sensor performance and increase the likelihood of defects during manufacturing.
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 enhances durability and prevents separation or wrinkling, while maintaining touch sensor functionality.
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 separation from inorganic encapsulation layer or 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 competing requirements: maintaining touch sensor performance by preventing capacitance interference while avoiding separation or wrinkling defects. This parameter optimization resolves the contradiction by finding the optimal value range that satisfies both conditions.
Solution Approach 2:
The patent employs a multilayer encapsulation structure combining organic and inorganic encapsulation layers. The inorganic layers (such as silicon oxide, silicon nitride, or silicon oxynitride) provide structural stability and prevent separation, while the organic layer with controlled permittivity maintains touch sensor performance. This composite structure resolves the contradiction by distributing functions across different material layers.
2Reliability
If the organic encapsulation layer has low relative permittivity to prevent capacitance interference, then touch sensor performance is maintained, 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 and reduces manufacturing defects. This parameter control approach resolves the contradiction by identifying the optimal parameter window that prevents both capacitance interference and manufacturing issues.
Solution Approach 2:
The patent applies different material properties to different layers of the encapsulation structure. The organic layer has specifically engineered permittivity characteristics for touch sensor compatibility, while inorganic layers provide structural integrity. This local differentiation of material qualities resolves the contradiction by assigning specific functions to specific layers.
3Object-affected harmful factors
If the second inorganic encapsulation layer has high density to provide barrier protection, then moisture and oxygen barrier performance is improved, but oxidation rate increases when exposed to humid environment
Solution Approach 1:
The patent optimizes the density of the second inorganic encapsulation layer to a specific range (greater than 1.8 g/cm³ and less than 2.03 g/cm³) to balance barrier performance and oxidation resistance. This parameter optimization resolves the contradiction by finding the density window that provides adequate moisture and oxygen blocking while maintaining stability in humid environments.
Solution Approach 2:
The patent uses a multilayer inorganic encapsulation structure where different inorganic layers (such as silicon oxide, silicon nitride, or silicon oxynitride) work together. The second inorganic layer with controlled density provides the barrier function, while the overall composite structure maintains oxidation resistance through synergistic effects of multiple materials.
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 and maintains touch sensor performance by providing enhanced protection against moisture and oxygen, ensuring the display apparatus' reliability and longevity.
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 compressive stress of greater than 60 megapascals (MPa) and less than 180 MPa
Implementation Method 3
the second inorganic encapsulation layer has a density of greater than 1.8 gram per cubic centimeters (g/cm3) and less than 2.03 g/cm3
Implementation Method 4
When the second inorganic encapsulation layer is exposed as an outermost layer of the display apparatus at a temperature of 85 degrees in Celsius (° C.) and a humidity of 85% for 504 hours, the second inorganic encapsulation layer may have an oxidation rate of greater than 0.7 angstroms per hours (Å/h) and less than 2.3 Å/h
Data Source
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.