Display Apparatus Organic Layer Overflow Control
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Solution Overview
Problem
Conventional organic light-emitting display apparatuses face issues with the organic layer overflowing beyond its intended region during the inkjet method of formation, leading to reliability concerns.
Innovation Solution
A display apparatus design featuring a substrate with a display area and peripheral area, including an optical functional layer with a first layer and a second layer of higher refractive index, where the first layer defines a valley portion with holes to control the spreading of the organic layer, and a thin-film encapsulation layer with organic and inorganic layers to prevent overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the organic layer is formed using the inkjet method, then the manufacturing process is simplified and productivity is improved, but the organic layer overflows to outside of the intended region leading to reliability issues
Solution Approach 1:
The patent applies preliminary action by forming a protrusion structure on the substrate before depositing the organic layer. This protrusion acts as a pre-established physical barrier that confines the organic material during the inkjet deposition process, preventing overflow before it can occur. The protrusion is created in advance through spin coating and photolithography processes, setting up the containment structure beforehand.
Solution Approach 2:
The protrusion structure serves as an intermediary element between the substrate and the organic layer. It mediates the interaction by providing a physical boundary that guides and confines the organic material deposition, preventing direct contact between the overflowing organic layer and the peripheral areas of the substrate. This intermediary structure effectively transfers the containment function from the substrate edge to the protrusion boundary.
2Area of stationary object
If the organic layer is allowed to spread freely during formation, then complete coverage is achieved, but the layer extends beyond the display area causing defects
Solution Approach 1:
The patent applies local quality by creating a protrusion structure with specific geometric properties (height, width, and position) that differs from the surrounding substrate plane. This localized structural modification provides targeted confinement exactly where needed at the boundaries of the display area, while allowing the organic layer to spread freely within the intended region. The protrusion's dimensions are optimized to provide sufficient barrier function without interfering with the display area coverage.
3Device complexity
If conventional flat substrate structure is used, then device complexity is minimized, but organic layer overflow cannot be controlled
Solution Approach 1:
The patent applies segmentation by dividing the substrate surface into distinct regions: a flat display area and a raised protrusion boundary region. This segmentation creates functional zones where the protrusion structure serves as a separate containment element distinct from the main substrate plane. The protrusion is formed as a discrete structural feature with defined boundaries, separating the organic layer confinement function from the general substrate support function.
Data Source
AI summary
Provided is a display apparatus having improved reliability by effectively controlling spreading of an organic layer. The display apparatus includes a substrate including a display area, and a peripheral area outside the display area, a display element at the display area, an input-sensing layer over the display element, and an optical functional layer on the input-sensing layer, and including a first layer, which corresponds to the display area and the peripheral area, and a second layer on the first layer, and having a greater refractive index than the first layer, wherein the first layer defines a first valley portion defining first holes that is on the peripheral area, and that surrounds the second layer.