Top-Emitting OLED Cathode Auxiliary Electrode Voltage Drop
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Solution Overview
Problem
In large-size top-emitting OLED devices, the voltage drop between the center and edge of the screen due to the high resistance of thin transparent metals affects the display effect, making it difficult to achieve uniform brightness.
Innovation Solution
A conductive auxiliary electrode layer is introduced on the non-light emitting region of the cathode layer, increasing the conductivity of the cathode layer without blocking the light emitting region, thereby reducing the voltage difference between the center and edge of the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a thin transparent metal is used as a cathode to ensure light transmittance, then the light transmittance is improved, but the resistance increases causing voltage drop and affecting display uniformity
Solution Approach 1:
The cathode structure is segmented into multiple layers: a thin transparent metal layer (first cathode layer) for light transmittance and a conductive auxiliary electrode layer (second cathode layer) for electrical conductivity. This segmentation allows each layer to specialize in one function, resolving the contradiction between transmittance and conductivity
Solution Approach 2:
The cathode uses a composite structure combining transparent metal (e.g., ITO, IZO) with conductive materials (e.g., Al, Mo, W) in sequential layers. This composite approach integrates the optical properties of transparent metal with the electrical properties of conductive materials, simultaneously achieving both light transmittance and low resistance
2Area of stationary object
If the screen size is increased for large-size OLED devices, then the display area is improved, but the voltage difference between center and edge increases due to resistance
Solution Approach 1:
The solution adds a new dimensional layer (the auxiliary electrode layer) to the existing cathode structure. This additional layer provides alternative current pathways in the vertical dimension, reducing the reliance on horizontal current flow through the resistive transparent metal, thereby reducing voltage drop across large areas
Solution Approach 2:
The auxiliary electrode layer acts as an intermediary between the transparent metal cathode and the driving circuit. It mediates the electrical connection by providing a low-resistance path that compensates for the high resistance of the transparent metal, enabling uniform voltage distribution across large screen areas
Data Source
AI summary
The present invention discloses a top-emitting OLED device, a method of manufacturing the same, and a display panel. The OLED device includes a substrate, an anode layer, an organic functional layer, a cathode layer, and an auxiliary electrode layer sequentially arranged, wherein the auxiliary electrode layer is arranged on the non-light emitting region of the cathode layer, and the material of the auxiliary electrode layer is electrically conductive. The present invention can increase the conductivity of the cathode layer, reduce the voltage difference between the center and the edge of the screen, and improve the display effect without blocking the light emitting region and not affecting the display brightness of the light emitting region.