OLED Encapsulation with Protruding Pixel-Defining Layer
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Solution Overview
Problem
Conventional organic light-emitting display apparatuses face challenges in encapsulating protruding portions on a pixel-defining layer, leading to increased thickness, processing time, and cost due to the low viscosity of organic films used, which can expose the protruding portions and require thicker encapsulating layers.
Innovation Solution
An organic light-emitting display apparatus with a thin film encapsulating layer comprising both organic and inorganic films, where the functional organic film has adjustable viscosity using light or temperature, allowing for a thinner encapsulation that effectively seals protruding portions without increasing the overall thickness, and includes a protective layer between the organic light-emitting device and the encapsulating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the thin film encapsulating layer is increased to cover protruding portions, then the protruding portions are sealed, but the thickness of the display apparatus increases
Solution Approach 1:
The patent applies local quality by creating a pixel-defining layer with protruding portions that have different heights at different locations. The encapsulating layer is designed to conform to these varying heights, providing localized sealing where needed while maintaining overall thinness. This resolves the contradiction by making the encapsulation thickness non-uniform - thicker only where protruding portions require sealing, rather than uniformly thick across the entire display.
Solution Approach 2:
The patent introduces a vertical dimension variation through the pixel-defining layer's protruding portions, which extend upward from the substrate surface. This creates a stepped or multi-level structure where the encapsulating layer can seal around these vertical features without requiring a uniform increase in overall thickness across the entire display area.
2Ease of manufacture
If the viscosity of the organic film is low to enable spreading, then the film can be applied easily, but the protruding portions are exposed when the film spreads
Solution Approach 1:
The patent employs parameter changes by utilizing the temperature-dependent viscosity characteristics of the organic film material. During the deposition process, the substrate or film is heated to increase viscosity, preventing the film from spreading and exposing protruding portions. After deposition, the temperature is reduced to decrease viscosity, allowing the film to self-heal and conform to the protruding portions. This dynamic parameter adjustment resolves the contradiction between ease of application and effective coverage.
3Reliability
If the thickness of the encapsulating layer is increased to ensure coverage, then protruding portions are sealed, but processing time and cost increase
Solution Approach 1:
The patent applies preliminary action by forming the pixel-defining layer with protruding portions before depositing the encapsulating layer. This pre-structured geometry guides the encapsulation process, allowing the film to be deposited as a thin uniform layer that automatically conforms to the protruding portions during subsequent thermal processing. This eliminates the need for thick initial deposition or multiple coating steps, thereby reducing processing time and cost while maintaining effective sealing.
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 solution enables efficient sealing of protruding portions with a reduced thickness of the organic light-emitting display apparatus, minimizing processing time and cost while maintaining effective encapsulation against air and moisture.
Implementation Method 1
a material having a viscosity that is adjustable using light or temperature
Implementation Method 2
a material having a viscosity that is adjustable using light or temperature
Data Source
AI summary
An organic light-emitting display apparatus is provided. The display apparatus includes a pixel-defining layer disposed on a substrate, wherein the pixel-defining layer defines an emission region and a non-emission region, an organic light-emitting device disposed in the emission region, and a protruding portion disposed on a portion of the pixel-defining layer in the non-emission region. The display apparatus also includes a thin film encapsulating layer disposed on the substrate for sealing the organic light-emitting device and the protruding portion, the thin film encapsulating layer comprising at least one organic film and at least one inorganic film, wherein at least one organic film corresponds to a functional organic film, and a height of a first upper surface of the functional organic film disposed away from the protruding portion is lower than a height of a second upper surface of the functional organic film disposed near a top of the protruding portion.