Hybrid Encapsulation for OLED Devices Using Segmented Barrier Layers
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Solution Overview
Problem
Conventional encapsulation methods for sensitive devices like OLEDs require multiple inert deposition chambers, increasing the size and cost of deposition machines due to the need for multiple dyads in the barrier stack, which is inefficient and costly.
Innovation Solution
A hybrid encapsulation approach using a first barrier layer with a suitable water vapor transmission rate for application in a non-inert environment, allowing for the use of a single deposition chamber and reducing the need for multiple inert chambers by using a temporary barrier layer that prevents damage during adhesive application and lamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple inert deposition chambers are used to deposit each barrier layer, then device protection from water vapor and oxygen is improved, but equipment size and manufacturing cost increase
Solution Approach 1:
The encapsulation structure is segmented into two functional parts: a thin inorganic barrier layer deposited directly on the device (requiring inert conditions) and a separate polymeric laminate applied afterwards (can be applied in non-inert conditions). This segmentation allows the inert chamber to be used only for the critical barrier layer deposition, while the laminate application can occur in a non-inert environment, reducing the need for multiple large inert chambers.
Solution Approach 2:
An adhesive layer is introduced as an intermediary between the inorganic barrier layer and the polymeric laminate. This adhesive mediator enables the laminate to be bonded to the barrier layer in a non-inert environment, allowing the separation of deposition and lamination processes into different environmental zones, thereby reducing equipment complexity.
2Reliability
If multiple inert deposition chambers are used for multilayer barrier stack deposition, then barrier performance is improved, but manufacturing cost increases
Solution Approach 1:
The manufacturing process is segmented into two stages: (1) deposition of the thin inorganic barrier layer in an inert environment, and (2) lamination of the polymeric laminate in a non-inert environment. This segmentation reduces the number of inert chambers required from multiple (one for each barrier layer) to just one (for the initial barrier layer), significantly lowering equipment costs while maintaining barrier performance.
Solution Approach 2:
The water vapor transmission rate parameter of the first barrier layer is specifically controlled to be suitable for application in non-inert environments. This parameter change enables the transition from requiring complete inert conditions for all barrier layers to allowing controlled non-inert conditions for the laminate application, reducing manufacturing costs.
3Ease of operation
If a thin inorganic barrier layer is used with higher water vapor transmission rate, then lamination can be performed in non-inert environment, but barrier protection capability may be compromised
Solution Approach 1:
A composite encapsulation structure is created combining two different materials with complementary properties: a thin inorganic barrier layer (alumina, silica, or silicon nitride) that provides initial protection and enables non-inert lamination, and a polymeric laminate that provides enhanced long-term barrier protection. The composite structure achieves both processability and reliability.
Solution Approach 2:
The thin inorganic barrier layer is deposited first as a preliminary protective layer before lamination. This preliminary action provides immediate protection to the device during subsequent handling and lamination processes in non-inert environments, preventing damage while enabling easier operation.
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
This approach simplifies the encapsulation process, reduces equipment size and costs, and effectively protects devices from harmful gases and liquids during the encapsulation process while allowing for the use of smaller, less expensive deposition apparatus.
Implementation Method 1
The first barrier layer has a water vapor transmission rate suitable to allow application of the adhesive and lamination of the first laminate on the first barrier layer in a non-inert environment
Implementation Method 2
a first barrier layer comprising a first barrier material deposited directly on the device
Implementation Method 3
a second barrier layer on the polymeric substrate
Data Source
AI summary
An encapsulated device achieves good water vapor transmission rates while reducing the amount of time needed in an inert environment, and thereby reducing the size of the deposition tool used to encapsulate the device. The encapsulated device includes a first barrier layer deposited directly on the device, and a first adhesive and first laminate on the first barrier layer. The laminate comprises a polymeric substrate and a second barrier layer on the substrate. The first barrier layer has a water vapor transmission rate suitable to allow lamination of the laminate on the first barrier layer in a non-inert environment. A method of making an encapsulated device comprises depositing a first barrier layer on the device in an inert environment, applying an adhesive on the first barrier layer in a non-inert environment, and applying a first laminate on the first adhesive in the non-inert environment.