OLED Lighting Anode Segmentation for Voltage Drop Compensation
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Solution Overview
Problem
Existing organic light-emitting diode (OLED) lighting apparatuses suffer from luminance uniformity issues due to voltage drops as distance increases from pad electrodes, leading to reduced overall luminance and shortened lifespan.
Innovation Solution
Incorporating a short-circuit reduction pattern with gradually reducing resistance between pixels and pad electrodes, formed by removing parts of the anode and covered with a passivation layer, to compensate for voltage drops and maintain luminance uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anode is formed as a continuous film in existing OLED lighting apparatuses, then the electrical connection between pixels and pad electrodes is established, but voltage drops occur as distance increases leading to luminance non-uniformity
Solution Approach 1:
The anode is divided into pixel electrode portions and pad electrode portions with different functions. The pixel electrode portions are selectively removed in non-emission zones to create isolation patterns, while pad electrode portions remain continuous for electrical connection. This local differentiation resolves the contradiction by allowing voltage compensation in emission zones while maintaining connectivity in pad zones.
Solution Approach 2:
The continuous anode film is segmented into discrete pixel electrode portions separated by removed regions. This segmentation prevents voltage drops from propagating across the entire panel while maintaining adequate electrical connection through the pad electrode portions. The segmented structure allows independent voltage compensation for each pixel region.
2Reliability
If the anode is removed in short-circuit reduction patterns to prevent short-circuits, then short-circuit reliability is improved, but electrical connection between pixels and pad electrodes may be compromised
Solution Approach 1:
The anode removal is applied locally only in non-emission zones surrounding pixel emission zones, while the pad electrode portions in emission zones are preserved. This selective removal prevents short-circuits between adjacent pixels while maintaining electrical connection to pad electrodes, resolving the contradiction between short-circuit prevention and electrical connectivity.
3Illumination intensity
If electrical current is concentrated in regions close to pad electrodes, then luminance is increased in those regions, but luminance uniformity deteriorates across the panel
Solution Approach 1:
The anode structure is modified to have different configurations in different regions: pixel electrode portions in emission zones maintain adequate thickness for current conduction, while the anode is removed in non-emission zones. This creates local quality differences that distribute current more uniformly across the panel, improving luminance uniformity while maintaining adequate luminance in each pixel region.
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
Improves luminance uniformity, extends the lifespan of the OLED lighting apparatus by ensuring consistent light emission across the panel, enhancing both performance and exterior quality.
Implementation Method 1
an organic layer and a cathode disposed on the passivation layer in the emission area of the substrate
Data Source
AI summary
A lighting apparatus including organic light-emitting diodes comprises an anode disposed in an emission area of a substrate; first and second pad electrodes disposed on an outer side of the emission area of the substrate; a short-circuit reduction pattern surrounding an emission zone of each of pixels and formed by removing a part of the anode; a passivation layer comprising the short-circuit reduction pattern and disposed on the anode; an organic layer and a cathode disposed on the passivation layer in the emission area of the substrate; and a metal film disposed in the emission area of the substrate, wherein the short-circuit reduction pattern has a gradually-reducing resistance with an increased distance between the pixels and the first and second pad electrodes.