OLED Display Layer Structure for White Angle Dependency Reduction
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Solution Overview
Problem
Display devices experience surface non-uniformity due to overlapping lines, leading to white angle dependency (WAD) issues, which affect viewing angles and display quality.
Innovation Solution
The implementation of a concave structure in the third interlayer insulating layer to increase the distance between the second conductive layer and the first electrode, combined with a planarized surface of the protective layer, which helps in reducing step differences and surface irregularities, thereby improving the uniformity of light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lines overlap with the display element, then the display device can be manufactured with standard layering, but surface non-uniformity occurs causing white angle dependency
Solution Approach 1:
The patent applies local quality by creating a recessed region specifically in the third interlayer insulating layer where the conductive layer and first electrode overlap. This localized modification allows the insulating layer to have different heights in different regions, compensating for the step difference caused by overlapping structures and achieving surface uniformity without changing the overall manufacturing process
Solution Approach 2:
The patent introduces a vertical dimension solution by forming a recessed region in the third interlayer insulating layer. This vertical adjustment compensates for the horizontal overlap of layers, creating a stepped structure that equalizes the surface height and eliminates the step difference that causes white angle dependency
2Manufacturing precision
If the distance between the second conductive layer and the first electrode is increased, then white angle dependency is reduced, but the device structure becomes more complex
Solution Approach 1:
The patent uses local quality by modifying only the third interlayer insulating layer to create a recessed region, while keeping other layers unchanged. This localized approach increases the distance between the second conductive layer and first electrode precisely where needed, without adding complexity to the overall device structure
Solution Approach 2:
The patent applies preliminary action by forming the recessed region in the third interlayer insulating layer before forming the second conductive layer. This preliminary modification ensures that when the second conductive layer is deposited, it automatically achieves the desired increased distance from the first electrode, simplifying subsequent manufacturing steps
Data Source
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AI summary
A display device includes: a substrate (SUB); pixels, the pixels each including at least one transistor (DE7, GE7, ACT7, SE7) and a light emitting device (OLED) connected to the transistor; data lines (Di) and scan lines (Si, Si-1) connected to the pixels; and a power line (PL) supplying power to the light emitting device. The transistor includes an active pattern (ACT7) on the substrate (SUB), source (SE7) and drain (DE7) electrodes each connected to the active pattern (ACT7), a gate electrode (GE7) on the active pattern (ACT7), an interlayer insulating layer (IL1) covering the gate electrode, the interlayer insulating layer including a first interlayer insulating layer (IL2), a second interlayer insulating layer (IL31), and a third interlayer insulating layer (IL32), which are sequentially stacked, and a protective layer (PSV) provided on the interlayer insulating layer. The third interlayer insulating layer (IL32) includes a concave part (CCP) in a region in which the light emitting device (OLED) and the second conductive layer (PL2) overlap with each other, and the second conductive layer (PL2) is in the concave part.