OLED Display Panel Boss Structure and Auxiliary Cathode Offset
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Solution Overview
Problem
Top emission OLED displays face challenges in achieving high brightness due to light emission passing through thick filler and insulating cover layers, which affects the gap between substrates and results in light leakage between sub-pixels.
Innovation Solution
The organic light emitting display panel design includes a cover plate with overlapping color films and a back plate featuring a planarization layer with a boss to position the OLED device closer to the cover plate glass, ensuring the OLED device and auxiliary cathode are offset, reducing the distance and preventing light leakage, and utilizing an insulating cover layer and spacer pillars to enhance adhesion and aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the gap between upper and lower substrates is increased to accommodate thick filler and insulating cover layers, then the structural integrity is improved, but the brightness is reduced due to light absorption and scattering
Solution Approach 1:
The patent introduces a boss structure (protrusion) in the planarization layer to create a vertical dimension change, allowing the OLED device to be positioned closer to the cover plate glass while maintaining the overall substrate gap. This dimensional adjustment reduces the light transmission path through filler and insulating layers, improving brightness without compromising structural integrity.
2Illumination intensity
If the distance between OLED device and cover plate glass is reduced to improve brightness, then the aperture ratio is increased, but light leakage between sub-pixels occurs
Solution Approach 1:
The patent introduces an auxiliary cathode as an intermediary component positioned between the OLED device and the cover plate glass. This auxiliary cathode, together with the offset positioning of the OLED device, creates a light-blocking barrier that prevents light leakage between sub-pixels while allowing the OLED to be positioned closer to the glass for improved brightness.
Solution Approach 2:
The patent employs asymmetric positioning by offsetting the OLED device relative to the auxiliary cathode and creating a non-uniform gap structure through the boss. This asymmetric arrangement allows the OLED to be closer to the cover plate in the pixel area (improving brightness) while maintaining adequate spacing in non-pixel areas (preventing light leakage).
3Object-affected harmful factors
If the overlapping width of color films is increased to prevent light leakage, then the aperture ratio is reduced, but the brightness is improved
Solution Approach 1:
The patent segments the light-blocking function by introducing an auxiliary cathode structure that works together with the color film overlap. This segmentation allows the color films to maintain minimal overlap (preserving aperture ratio) while the auxiliary cathode provides additional light-blocking capability to prevent light leakage between sub-pixels.
Data Source
AI summary
An organic light emitting display panel includes a cover plate and a back plate. The cover plate includes a cover plate glass on which three color films of R, G and B are formed. The cover plate includes an insulating cover layer covering the cover plate glass. The cover plate includes a BM area formed over the insulating cover layer and defining a pixel area. The cover plate includes a spacer pillar formed in the BM area. The cover plate includes an auxiliary cathode formed over the spacer pillar and the insulating cover layer. The back plate includes: an active layer array; a planarization layer formed on the active layer array, having a boss corresponding to the pixel area; and an OLED device formed on the boss.