Multi-Screen OLED Electrode Layout for Uniform Luminance
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Solution Overview
Problem
Existing top emission mode organic light emitting displays suffer from non-uniform luminance between the edge and central portions due to increased resistance in the common electrode, and multi-screen displays have visible seams due to bezel areas, reducing image immersion.
Innovation Solution
A display apparatus with a substrate, common electrode, auxiliary electrode, height control layer, and auxiliary electrode contact portion is designed to ensure uniform luminance by applying common voltage directly to the central portion, and a multi-screen display apparatus with similar components minimizes bezel width to eliminate seams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the common electrode is formed to be thin to allow light transmission, then transparency is improved, but electrical resistance increases causing non-uniform luminance
Solution Approach 1:
The common electrode is divided into two functional parts: a transparent common electrode for light transmission and a separate auxiliary electrode for voltage supply. This segmentation allows the common electrode to remain thin and transparent while the auxiliary electrode compensates for resistance issues by providing additional voltage pathways.
Solution Approach 2:
The auxiliary electrode acts as an intermediary element between the power source and the common electrode. It provides an additional voltage supply path that compensates for the high resistance of the thin common electrode, ensuring uniform voltage distribution and thus uniform luminance across the display.
2Area of stationary object
If the bezel area is reduced to minimize width, then device compactness is improved, but the mechanism for covering edge portions becomes difficult to implement
Solution Approach 1:
The solution moves the coverage function from the horizontal plane (bezel width) to the vertical dimension (edge portion coverage). The auxiliary electrode and associated structures cover the edge portions in the thickness direction, allowing the bezel width in the horizontal plane to be minimized while still providing necessary coverage and protection.
3Area of stationary object
If multiple display apparatuses are arranged in a grid shape to create multi-screen display, then screen size is increased, but visible seams reduce image immersion
Solution Approach 1:
The auxiliary electrode is selectively positioned at the edge portions of the display panel, providing localized voltage compensation where needed. This local quality approach allows the central display area to maintain high image quality and continuity, while the edge portions receive additional voltage support to prevent luminance non-uniformity, thereby maintaining image immersion across multiple screens.
Data Source
AI summary
A display apparatus having a thin bezel width while preventing non-uniform luminance of an image from occurring and a multi-screen display apparatus including the same are provided. The display apparatus includes a substrate having a display portion, a plurality of pixels disposed in the display portion, a common electrode disposed in the display portion and electrically connected to each of the plurality of pixels, an auxiliary electrode electrically connected to an auxiliary voltage line extended from an edge portion of the substrate to the display portion, a height control layer provided between the substrate and the auxiliary electrode, and an auxiliary electrode contact portion disposed between the plurality of pixels, wherein the common electrode may be in contact with the auxiliary electrode covering a side of the height control layer in the auxiliary electrode contact portion.