Display Power Electrode Layout for Uniform OLED Image Quality
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Solution Overview
Problem
Display devices face issues with non-uniform image quality due to increased resistance in the non-display area, leading to voltage variations, and thin film encapsulation reliability is compromised when organic materials overflow, exposing them to air and moisture.
Innovation Solution
A display device design featuring a base layer with defined display and non-display areas, a circuit layer, planarization layers, a light emitting element layer, and a thin film encapsulation layer, where the second power electrode overlaps the driving circuits and extends to reduce resistance and prevent organic material overflow through groove parts and dams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the non-display area is reduced to increase the display area, then the display area increases, but the resistance of elements in the non-display area increases causing non-uniform image quality
Solution Approach 1:
The patent extends the power electrode in the vertical direction (thickness dimension) to form a via structure that penetrates through the non-display area. This dimensional transition allows the power electrode to maintain low resistance by providing multiple conduction paths through the stacked layers, compensating for the reduced horizontal area in the non-display region.
Solution Approach 2:
The via structure employs composite material construction with different conductive materials in different layers. The power electrode includes first and second conductive materials with different resistivity characteristics, optimized for their respective positions and functions, achieving overall low resistance performance despite the constrained non-display area.
2Area of stationary object
If the non-display area is reduced to increase the display area, then the display area increases, but voltage level varies according to position
Solution Approach 1:
The power electrode transitions from a planar structure to a vertical via structure that penetrates through the non-display area. This dimensional change creates multiple parallel conduction paths through the stacked layers, reducing voltage drop and maintaining uniform voltage distribution across the display area despite the reduced non-display region.
Solution Approach 2:
The power electrode is segmented into multiple sections corresponding to different layers (first power electrode, second power electrode, via structure). Each segment is optimized for its specific layer, with conductive materials and dimensions tailored to minimize resistance at each interface, ensuring overall voltage uniformity.
3Ease of manufacture
If organic material overflows during formation, then the organic layer is exposed to air and moisture, but the thin film encapsulation reliability deteriorates
Solution Approach 1:
The encapsulation layer is designed with extended side surfaces that proactively cover potential overflow regions of the organic material. By anticipating the overflow direction and extent, the encapsulation layer is formed to extend beyond the nominal organic layer boundaries, preventing exposure before it occurs.
Solution Approach 2:
The side surfaces of the encapsulation layer are formed in advance to extend over the organic layer and underlying layers. This preliminary structural preparation ensures that even if organic material overflows during subsequent processing, the encapsulation barrier is already in place to prevent air and moisture penetration.
Data Source
AI summary
A display device includes a base layer on which a display area and a non-display area are defined, a circuit layer including a first power electrode and driving circuits, which are disposed in the non-display area, a first planarization layer in which a first opening through which the first power electrode is exposed is defined and which covers the driving circuits, a second power electrode disposed on the first planarization layer to contact the first power electrode that is exposed through the first opening and overlapping at least a portion of the driving circuits, and a second planarization layer disposed on the first planarization layer to cover a portion of the second power electrode and having a groove part in an area overlapping the first planarization layer and the second power electrode in a plan view.