Microdisplay Encapsulation Thickness Preventing Color Mixing
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Solution Overview
Problem
Existing microdisplay devices face issues with color mixing due to inadequate encapsulation, which allows moisture and oxygen to degrade the light-emitting diodes, especially when exposed to organic materials, leading to reduced display quality.
Innovation Solution
A microdisplay device with a substrate, pixels, and an encapsulation layer where the distance between the pixels and the encapsulation layer's thickness satisfy the relation t≤ (d/tan 10°), preventing color mixing by effectively sealing the light-emitting elements and protecting them from environmental factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the encapsulation layer thickness is increased to protect light-emitting diodes from moisture and oxygen, then the protection effectiveness is improved, but color mixing between adjacent pixels occurs
Solution Approach 1:
The patent optimizes the encapsulation layer thickness to a specific range (50-200 nm) to simultaneously achieve adequate protection against moisture and oxygen while preventing color mixing between adjacent pixels. This parameter optimization resolves the contradiction by finding the precise thickness value that balances both requirements.
Solution Approach 2:
The patent employs a composite encapsulation structure consisting of multiple layers with different materials and functions. The first encapsulation layer (inorganic material like SiO2 or Si3N4) provides barrier protection, while the second encapsulation layer (organic material like PMMA or PI) provides additional protection and flexibility. This composite structure achieves both protection effectiveness and color mixing prevention.
2Object-generated harmful factors
If the encapsulation layer thickness is decreased to prevent color mixing, then color mixing is prevented, but the protection against moisture and oxygen is insufficient
Solution Approach 1:
The patent uses a multi-layer composite encapsulation structure where the first inorganic layer provides a dense barrier against moisture and oxygen penetration, while the second organic layer adds supplementary protection. This composite approach enables adequate protection even when individual layer thicknesses are reduced, thereby preventing color mixing while maintaining reliability.
Solution Approach 2:
The patent specifies precise thickness parameters for each encapsulation layer (first layer: 50-200 nm, second layer: 50-200 nm) to optimize the balance between protection and color mixing prevention. By controlling these parameters within specific ranges, the patent achieves both objectives simultaneously.
3Reliability
If a multi-layer encapsulation structure is used to improve protection, then the protection effectiveness is enhanced, but the device complexity increases
Solution Approach 1:
The patent employs a two-layer composite encapsulation structure with distinct material compositions and functions. The first inorganic layer provides barrier protection, while the second organic layer provides additional protection and planarization. This composite structure enhances protection effectiveness while maintaining manageable complexity through clear functional differentiation.
Solution Approach 2:
The patent applies different material qualities to different layers based on their specific functions. The inorganic layer is designed with high barrier properties for moisture and oxygen resistance, while the organic layer is designed with good coverage and planarization properties. This local quality optimization enhances overall protection without unnecessarily increasing complexity.
Data Source
AI summary
A display device includes a substrate, a plurality of pixels, and an encapsulation layer. The encapsulation layer is disposed on the pixels. The encapsulation layer has a multi-layer structure or a single-layer structure. When a distance (d) between the pixels and a thickness (t) of the encapsulation layer satisfies Mathematical Formula 1: t≤ (d/tan 10°), color mixing is prevented in the display device.