OLED Current Distribution via Corner Separator
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Solution Overview
Problem
Organic light emitting diode (OLED) devices are prone to hot spots at the corners of the light emitting area due to high current density, leading to reduced lifespan and potential damage, as existing solutions like modifying corner geometry disturb visual perception and limit design options.
Innovation Solution
A separator with higher sheet resistance than the electrode contact is introduced between the anode contact area and the light emitting area, specifically in the corner regions, to reduce local current density and prevent hot spots, allowing for efficient current distribution and heat management without altering the device's geometric design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If corner geometry is modified (cutting corners or increasing corner radius) to reduce hot spots, then current distribution is improved, but visual perception is disturbed and design options are limited
Solution Approach 1:
The patent applies local quality by introducing a separator with different electrical properties (higher sheet resistance) specifically in the corner regions, rather than modifying the overall corner geometry. This allows the majority of the light emitting area to maintain its intended shape and visual appearance, while only the corner regions have modified electrical characteristics to reduce current density and prevent hot spots.
2Reliability
If separator with higher sheet resistance is introduced in corner regions, then hot spots are reduced and current distribution is improved, but device complexity increases
Solution Approach 1:
The patent segments the electrode contact structure by introducing a separator that divides the corner regions from the main light emitting area. This segmentation allows different electrical properties in different regions, with the separator having higher sheet resistance to block excess current in corners while the main area maintains its original conductivity for optimal light emission.
Solution Approach 2:
The separator acts as an intermediary element between the electrode contact and the light emitting area in corner regions. It mediates the current flow by providing a controlled resistance path that prevents excessive current density in corners without completely blocking current, thus reducing hot spots while maintaining overall device functionality.
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 approach effectively reduces the occurrence of hot spots by distributing current homogeneously, extending the device's lifespan and improving its sensitivity to external stresses without compromising visual aesthetics.
Implementation Method 1
a separator between the electrode sheet and the electrode contact, wherein the separator is formed of an isolating material and/or a material having a sheet resistance higher than a sheet resistance of the electrode contact
Data Source
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AI summary
The invention relates to an organic light emitting diode device having an electrode sheet (1) of a light emitting area and an electrode contact (12) in contact with the electrode sheet (1), to a method for forming such OLED device and to method of operating such OLED device. In order to provide such OLED device having a reduced tendency for the occurrence of hot spots, the present invention provides for reducing a local and/or average regional current density of a current flowing in operation of the lighting device through an interface between the electrode sheet and the electrode contact in a comer area of the interface.