Auxiliary Wiring Laminate for Display Electrode Oxidation
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Solution Overview
Problem
Organic EL display devices of the top emission type face issues with uneven voltage distribution across electrodes due to high resistivity, leading to increased power consumption and decreased display quality, particularly when auxiliary wiring made from the same material as the electrodes oxidizes, causing higher connecting resistance.
Innovation Solution
The implementation of a display device with auxiliary wiring made from a material with lower resistance than the electrodes, connected through a laminate structure of conductive layers where the lowermost layer is in direct contact with the electrodes, ensuring stable electrical connection even if the upper layers oxidize.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auxiliary wiring is formed from the same material as the electrode (aluminum or aluminum alloy), then the connecting resistance is initially low, but surface oxidation occurs resulting in increased connecting resistance and higher power consumption
Solution Approach 1:
The patent applies composite materials by forming auxiliary wiring using a laminate structure of multiple conductive layers (e.g., aluminum alloy layer combined with protective layer). This composite structure prevents surface oxidation of the aluminum while maintaining low electrical resistance, thus resolving the contradiction between initial low connecting resistance and long-term oxidation resistance.
Solution Approach 2:
The patent introduces an intermediary protective layer (such as titanium nitride or other oxidation-resistant conductive material) that mediates between the aluminum electrode and the oxidizing environment. This intermediary layer prevents direct oxidation of the aluminum while maintaining good electrical conductivity, thereby preventing increasing connecting resistance over time.
2Illumination intensity
If ITO is used as the electrode material for light emission, then light transmission is achieved, but the high resistivity causes voltage fluctuation and deteriorates display quality
Solution Approach 1:
The patent uses composite electrode structures combining ITO with additional conductive layers (such as aluminum oxide or other transparent conductive oxides). This composite structure maintains the light transmission properties of ITO while adding layers that reduce overall resistivity and stabilize voltage distribution across the electrode.
Solution Approach 2:
The patent merges multiple electrode layers with complementary properties - combining the high light transmission of ITO with the low resistivity of metallic layers or other transparent conductive materials. This merged structure achieves both good light transmission and stable voltage distribution, resolving the contradiction between illumination quality and electrical stability.
Data Source
AI summary
A display device having a plurality of driving elements and wiring parts electrically connected to the driving parts, the display device includes: a plurality of first electrodes which are formed in correspondence to each driving element on the driving elements and the wiring parts; a plurality of light-emitting parts which are each formed on the first electrodes; a common second electrode which is formed from a material that transmits light from the light-emitting part and is formed on the light-emitting parts; auxiliary wiring parts with a lower resistance than the second electrodes; and contact parts which are formed in laminate structure from a plurality of conductive layers and which electrically connect the second electrodes and the auxiliary wirings with each other, with at least the lowermost conductive layer of the conductive layers of the contact parts being in direct contact with the second electrode.