OLED Lighting Apparatus High-Resistance Anode Short-Circuit Prevention
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Solution Overview
Problem
Organic light emitting diodes (OLEDs) in lighting apparatuses suffer from short-circuits due to contact between the anode and cathode, leading to reduced luminance and operational failures, which cannot be completely avoided despite manufacturing in clean rooms, as structural issues and foreign material permeation still occur.
Innovation Solution
The use of a first electrode formed from a transparent conductive material with high resistance, eliminating the need for separate resistive layers or patterns, and incorporating conductive patterns with low resistance in each pixel to manage current distribution and prevent overcurrent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent conductive material with high resistance is used for the first electrode, then short-circuit failures are suppressed, but electrical conductivity is reduced
Solution Approach 1:
The patent applies local quality by creating conductive patterns within the first electrode that have different electrical properties from the surrounding areas. These conductive patterns are strategically positioned to provide low-resistance current paths while the rest of the electrode maintains high resistance to prevent short-circuits between adjacent pixels.
Solution Approach 2:
The first electrode is segmented into multiple conductive patterns rather than being a continuous layer. This segmentation allows different regions to serve different functions: some regions provide conductivity while others maintain resistance to prevent short-circuits, resolving the contradiction between these two requirements.
2Length of stationary object
If the distance between anode and cathode is reduced, then device thickness is minimized, but short-circuit risk increases due to pinholes and cracks
Solution Approach 1:
The high-resistance transparent conductive material acts as an intermediary between the anode and cathode. Even when the distance between electrodes is reduced, this intermediate layer with controlled resistance properties prevents direct short-circuiting through pinholes and cracks, allowing thin device design while maintaining reliability.
3Manufacturing precision
If the organic light emitting layer thickness is reduced, then manufacturing precision requirements are lowered, but short-circuit probability increases
Solution Approach 1:
The patent converts the potential harm of a thin organic light emitting layer (which increases short-circuit risk) into a benefit by incorporating high-resistance transparent conductive material. This material compensates for the reduced insulation provided by the thin layer, allowing manufacturing with lower precision requirements while maintaining electrical insulation and preventing short-circuits.
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 solution effectively suppresses short-circuit failures and maintains luminance by ensuring that even if the anode and cathode contact, the high resistance of the first electrode prevents overcurrent, while the conductive patterns improve conductivity, maintaining the aperture ratio and preventing luminance degradation.
Implementation Method 1
a first electrode of an organic light emitting diode is formed by a transparent conductive material having a high resistance
Implementation Method 2
a light emitting device including an organic light emitting diode
Data Source
Figure 1
Figure 2~3B
Figure 4A~4B
AI summary
A lighting apparatus of the present disclosure includes an organic light emitting diode formed by a first electrode, an organic light emitting layer, and a second electrode on a first substrate and configures the first electrode by a transparent conductive material having a resistance of 2800 to 5500 Ω in each pixel. Therefore, even though the first electrode and the second electrode are in contact with each other to remove the resistance by the organic light emitting layer in the pixel, the overcurrent is suppressed from being applied to the pixel by the resistance of the first electrode. Further, at least one conductive pattern formed of a low resistance transparent conductive material which is connected to the first electrode in the pixel is disposed to suppress the degradation of the luminance by the first electrode having a high resistance.