Oxidized Second Electrode Edge for Transparent OLED
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Solution Overview
Problem
The optical transparency of light-emitting devices using organic electroluminescence (EL) is compromised due to the spreading of the second electrode during patterning, leading to a narrower region without the electrode and reduced transparency.
Innovation Solution
A light-emitting device configuration where the second electrode extends outside the light-emitting unit and is oxidized at its ends, preventing the electrode from spreading and maintaining optical transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the second electrode is patterned using vapor deposition with a mask, then the electrode can be formed in a specific pattern, but the vapor deposition material leaks out from the gap between the mask and substrate, causing the electrode end to spread outward
Solution Approach 1:
The patent applies preliminary action by forming a protective film on the substrate before vapor deposition of the second electrode. This protective film prevents vapor deposition material from leaking at the mask-substrate gap, thereby preventing electrode spreading while maintaining patterning precision. The protective film is removed after electrode formation, leaving a clean electrode edge without spread.
2Reliability
If the second electrode is extended outside the light-emitting unit to improve electrical connection, then the electrical reliability is improved, but the optical transparency of the device decreases
Solution Approach 1:
The patent applies local quality by differentiating the properties of different portions of the second electrode. The portion within the light-emitting unit maintains high conductivity for electrical connection, while the portion extending outside is made transparent or transparent-conductive to maintain optical transparency. This allows the electrode to simultaneously fulfill electrical and optical requirements in different regions.
3Illumination intensity
If the region without the second electrode is made larger to improve optical transparency, then the transparency increases, but the electrical connection reliability decreases
Solution Approach 1:
The patent resolves this contradiction by transitioning to another dimension - using vertical layering instead of horizontal expansion. Multiple transparent-conductive oxide layers are stacked to provide both electrical conductivity and optical transparency in the electrode extending outside the light-emitting unit, thereby maintaining both transparency and electrical reliability simultaneously.
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 effectively prevents the reduction in optical transparency by ensuring the light-transmitting region remains intact, even if the second electrode spreads, thereby maintaining the device's optical transparency.
Implementation Method 1
light-emitting devices using organic EL
Implementation Method 2
at least an end of a portion of the second electrode located outside the light-emitting unit being oxidized
Data Source
AI summary
A substrate (100) has optical transparency, and a light-emitting unit (140) is formed on the substrate (100). The light-emitting unit (140) includes a first electrode (110), an organic layer (120), and a second electrode (130). The organic layer (120) is located between the first electrode (110) and the second electrode (130). The second electrode (130) extends outside the light-emitting unit (140). At least an end of a portion of the second electrode (130) which is located outside the light-emitting unit (140) is oxidized.