Multi-Layer Encapsulation Stack for Environmental Permeation
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Solution Overview
Problem
Existing encapsulation stacks in devices like electrochromic (EC) devices and OLEDs are prone to degradation due to environmental element permeation through gap spaces formed by particles larger than the barrier layer thickness, leading to localized detachment and failure, which compromises the device's functionality.
Innovation Solution
A multi-layer encapsulation stack is applied with consecutive barrier layers, where each layer is preceded by surface cleaning to fill in gap spaces and prevent continuous permeation pathways, using a combination of inorganic and organic layers to enhance adhesion and reduce compressive stress, thereby increasing the stack's durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single barrier layer is applied to protect the device, then the device structure is simple, but environmental elements can permeate through gap spaces formed by particles, leading to device degradation
Solution Approach 1:
The encapsulation stack is divided into multiple individual barrier layers (e.g., first barrier layer, second barrier layer, third barrier layer) with different materials and functions. Each layer segments the protection task, with some layers providing permeation resistance and others providing adhesion or stress management, collectively preventing environmental element permeation through gap spaces
Solution Approach 2:
The barrier layers are constructed from composite materials with different properties - inorganic materials (such as aluminum oxide, silicon oxide) for permeation resistance, and organic materials for adhesion and flexibility. This composite structure addresses the limitation of single-material layers by combining the advantages of different material types to prevent both permeation and detachment
2Ease of manufacture
If particles are present on the surface during barrier layer application, then the application process is simpler, but gap spaces form around particles, creating permeation pathways
Solution Approach 1:
Surface cleaning is performed as a preliminary action before applying each barrier layer to remove particles that would create gap spaces. This preventive measure ensures continuous barrier layers by eliminating the root cause of permeation pathways before the layers are deposited
Solution Approach 2:
The multi-layer structure provides beforehand cushioning against the harmful effect of particles. Even if particles are present, the multiple layers with different materials and properties prevent complete permeation pathways, cushioning the device against degradation from manufacturing imperfections
3Reliability
If barrier layer thickness is increased to prevent permeation, then permeation resistance improves, but compressive stress increases, leading to localized detachment and failure
Solution Approach 1:
The total barrier thickness is segmented into multiple thinner layers rather than one thick layer. Each individual layer has reduced compressive stress while maintaining permeation resistance through the use of low-permeability materials, preventing localized detachment and failure
Solution Approach 2:
Composite materials with different mechanical properties are used in different layers. Some layers are designed with higher flexibility and adhesion properties to manage stress, while other layers provide permeation resistance, creating a balanced structure that maintains both strength and permeation protection
4Manufacturing precision
If a conformal barrier layer is applied over particles, then complete coverage is achieved, but gap spaces form around particles, creating permeation pathways
Solution Approach 1:
Surface cleaning is performed beforehand to remove particles that would create gap spaces, cushioning against the formation of permeation pathways. This preliminary action maintains both conformality and reliability by eliminating the source of the problem
Solution Approach 2:
The use of composite barrier layers with different material properties allows the stack to maintain conformal coverage while compensating for gap spaces. The multi-material structure provides redundant protection pathways, ensuring permeation resistance even when conformality is compromised by surface particles
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 multi-layer encapsulation stack effectively prevents environmental element permeation, maintaining device functionality by sealing gap spaces and reducing the probability of continuous permeation pathways, even under flexing conditions, thus enhancing the durability and reliability of sensitive devices.
Implementation Method 1
a barrier layer applied to a substrate-distal surface of the device, which restricts permeation of environmental elements from an external environment to the apparatus
Implementation Method 2
a process via which the encapsulation stack is applied to the apparatus includes: cleaning a presently-exposed apparatus surface prior to application of each of the multiple barrier layers
Data Source
AI summary
A process for encapsulating an apparatus to restrict environmental element permeation between the apparatus and an external environment includes applying multiple barrier layers to the apparatus and preceding each layer application with a separate cleaning of the presently-exposed apparatus surface, resulting in an apparatus which includes an encapsulation stack, where the encapsulation stack includes a multi-layer stack of barrier layers. Each separate cleaning removes particles from the presently-exposed apparatus surface, exposing gaps in the barrier layer formed by the particles, and the subsequently-applied barrier layer at least partially fills the gaps, so that a permeation pathway through the encapsulation stack via gap spaces is restricted. The quantity of barrier layers applied to form the stack can be based on a determined probability that a stack of the particular quantity of barrier layers is independent of at least a certain quantity of continuous permeation pathways through the stack.