Discontinuous Insulating Layer for OLED Height Uniformity
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Solution Overview
Problem
Existing organic light-emitting display apparatuses face challenges in reducing extreme height changes in insulating layers, which can lead to failures in the formation of the pixel-defining layer during manufacturing, especially when transitioning from the display area to the outermost area through the peripheral area.
Innovation Solution
The implementation of a substrate structure with a first insulating layer that is discontinuous in the peripheral area, a second insulating layer positioned on the first insulating layer in the display area and under it in the discontinuous portions, and a buffer layer, which helps in reducing extreme height changes by maintaining consistent heights across the display, peripheral, and outermost areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous insulating layer structure is used across the display area and peripheral area, then the insulating layer provides continuous protection and support, but extreme height changes occur when transitioning from the display area to the outermost area
Solution Approach 1:
The first insulating layer is divided into continuous and discontinuous portions across different areas. In the display area, it forms a continuous layer providing protection, while in the peripheral area, it becomes discontinuous to accommodate height variations and prevent extreme height changes at transitions to the outermost area.
Solution Approach 2:
The insulating layer structure is optimized locally for different areas: the first insulating layer is continuous in the display area for protection but discontinuous in the peripheral area for height control, while the second insulating layer is positioned differently in each area to maintain overall height uniformity across the substrate.
2Manufacturing precision
If the first insulating layer is made discontinuous in the peripheral area to reduce height changes, then height uniformity is improved, but the continuous protection and support function is compromised
Solution Approach 1:
The second insulating layer acts as an intermediary that compensates for the discontinuity of the first insulating layer. It is positioned on the first insulating layer in the display area and on the buffer layer in the discontinuous portions in the peripheral area, maintaining continuous protection and support while allowing height uniformity.
3Device complexity
If extreme height changes are not controlled, then the insulating layer structure is simpler, but the pixel-defining layer formation fails during manufacturing
Solution Approach 1:
The insulating layer structure is segmented into multiple layers (first and second insulating layers) with different continuity patterns in different areas, creating a more complex structure that prevents height extremes and enables successful pixel-defining layer formation.
Data Source
AI summary
An organic light-emitting display apparatus includes a substrate including a display area, a peripheral area surrounding the display area, and an outermost area surrounding the peripheral area, a first insulating layer on the substrate across the display area, the peripheral area, and the outermost area, the first insulating layer being discontinuous in the peripheral area, a second insulating layer on the substrate across the display area and the peripheral area, is the second insulating layer being positioned on the first insulating layer in the display area and on a layer under the first insulating layer in a discontinuous portion of the first insulating layer in the peripheral area, and a pixel electrode on the second insulating layer in the display area.