OLED Lighting Assembly Electrode Layout for Uniform Brightness
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Solution Overview
Problem
Lighting panels with electroluminescent devices like OLEDs face issues with brightness non-uniformity due to poor electrical conductivity of electrodes, leading to voltage drops and limiting their application in 'bezel-less' designs.
Innovation Solution
A lighting assembly with a substrate featuring rotationally symmetric electrode regions, each comprising a first and second external electrode, connected via a wire layer to ensure even current distribution and individual controllability, integrated with an electroluminescent layer for improved brightness uniformity and reduced peripheral area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If transparent electrode made of ITO material is used in OLED lighting panel, then the electrode can be transparent and allow light transmission, but the electrical conductivity is poor leading to large voltage drop and brightness non-uniformity
Solution Approach 1:
The patent divides the electrode structure into multiple segments: transparent conductive oxide layers (ITO) are segmented into separate anode and cathode transparent electrodes, and metal reflective electrodes are introduced as additional segments to create multiple current transmission paths. This segmentation allows each electrode type to perform its optimal function while collectively improving current distribution uniformity across the lighting panel.
2Reliability
If wider stripe-shaped external electrodes are used to improve current distribution, then the electrical conductivity improves, but a peripheral region is required that reduces the light emitting area and limits bezel-less design
Solution Approach 1:
The patent transitions from a two-dimensional planar electrode arrangement to a three-dimensional stacked structure by introducing metal reflective electrodes beneath the transparent electrodes. This dimensional change allows current to be supplied from multiple directions (top and bottom), enabling uniform current distribution without requiring wide peripheral electrodes that would reduce the light emitting area.
3Reliability
If peripheral region is dedicated to external electrodes, then the electrical connection is improved, but the application in bezel-less design is limited
Solution Approach 1:
The patent merges the functions of transparent electrodes and metal reflective electrodes into a unified dual-electrode structure. The transparent electrodes provide both electrical connection and light transmission functions, while the metal reflective electrodes provide electrical connection and current distribution functions, eliminating the need for separate peripheral electrode regions and enabling bezel-less designs.
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
The solution provides enhanced brightness uniformity and design flexibility by ensuring equal current transmission paths and eliminating the need for a peripheral electrode region, allowing for seamless integration and improved thermal distribution.
Implementation Method 1
The plurality of the electrode regions are arranged such that a pattern of the plurality of electrode regions is rotationally symmetric with respect to a center of the first surface. The lighting assembly comprises a wire layer below the first electrode layer, the first electrode layer is electrically connected to the first external electrode via a wire of the wire layer
Implementation Method 2
the light emitting region comprising a first electrode layer, an electroluminescent layer, and a second electrode layer arranged sequentially in a direction away from the substrate
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D~3A
AI summary
Disclosed is a lighting assembly including a substrate, at least one electrode region, and a light emitting region. The light emitting region surrounds at least one surrounded electrode region of the at least one electrode region. Also disclosed is a lighting device including the lighting assembly.