OLED Second Electrode Segmentation for Voltage Drop Reduction
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Solution Overview
Problem
Conventional OLED displays experience voltage drop due to electrical resistance in the thin film second electrode, which affects the driving power supplied to the organic emission layer.
Innovation Solution
The OLED display incorporates a first auxiliary electrode welded to the second electrode, with a spacer between the auxiliary electrode and the second substrate, and a second auxiliary electrode separated from the first electrode, both electrically connected to a power supply, to minimize voltage drop by reducing sheet resistance and contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a thin film second electrode is used in the OLED display, then the device thickness and weight are reduced, but voltage drop occurs due to electrical resistance in the thin film electrode
Solution Approach 1:
The second electrode is divided into a main body portion and an auxiliary electrode portion that are spatially separated. The auxiliary electrode is positioned to face the first electrode through the organic emission layer, creating a segmented configuration that reduces electrical resistance in the thin film electrode while maintaining overall device thinness.
Solution Approach 2:
The organic emission layer serves as an intermediary medium between the first electrode and the auxiliary electrode portion of the second electrode. This intermediary structure allows electrical connection while maintaining the thin film configuration, resolving the contradiction between thin electrode design and voltage stability.
2Illumination intensity
If the second electrode is formed as a thin film to minimize light absorption, then optical performance is improved, but contact resistance increases affecting power supply efficiency
Solution Approach 1:
The second electrode is segmented into a thin film main body for optimal light transmission and a separate auxiliary electrode portion for improved electrical contact. This segmentation allows the main body to maintain low light absorption while the auxiliary portion provides low-resistance electrical pathways.
Solution Approach 2:
Different portions of the second electrode have different functional qualities: the main body is optimized for optical performance with thin film structure, while the auxiliary electrode portion is optimized for electrical performance with configurations that minimize contact resistance. This local differentiation resolves the contradiction between optical and electrical requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration minimizes the voltage drop of common power across the second electrode, enhancing the efficiency of power supply to the organic emission layer and reducing sheet resistance, thereby improving the overall performance of the OLED display.
Implementation Method 1
The first auxiliary electrode is welded to the portion of the second electrode by irradiating an interface therebetween
Data Source
AI summary
An organic light emitting-diode (OLED) display is disclosed. In one aspect, the OLED includes a first substrate, a first electrode provided on the first substrate, a pixel defining layer provided on the first electrode and including a first opening exposing at least a portion of the first electrode, and an organic emission layer provided on the first electrode corresponding to the first opening. The OLED display also includes a second electrode provided on the pixel defining layer and the organic emission layer, a second substrate provided on the second electrode, and a first auxiliary electrode provided below the second substrate facing the second electrode and welded to a portion of the second electrode corresponding to the pixel defining layer.