Large-Area Display Device With Auxiliary Cathodes for Brightness Uniformity
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Solution Overview
Problem
As display devices increase in size, brightness uniformity decreases, affecting the quality of the display.
Innovation Solution
A display device design featuring a substrate, cathode and anode electrodes, light emitting layers, light conversion layers, an auxiliary electrode, and a conductive via, with specific ratios and configurations to enhance brightness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display device size is increased, then the display area is enlarged, but the brightness uniformity decreases
Solution Approach 1:
The cathode electrode is divided into a main cathode electrode and multiple auxiliary cathode electrodes. The auxiliary cathode electrodes are positioned at different locations (including corner regions) to segment the current distribution across the display area. This segmentation enables more uniform current density distribution, which directly improves brightness uniformity while maintaining the ability to drive large-area displays.
Solution Approach 2:
Different regions of the display device are provided with different electrode configurations. The auxiliary cathode electrodes are strategically placed in specific regions (such as corner regions) where current density tends to be non-uniform. This local quality approach addresses brightness uniformity issues in specific problem areas without requiring complete redesign of the entire electrode structure.
2Illumination intensity
If auxiliary cathode electrodes are added to improve brightness uniformity, then the electrical connection complexity increases
Solution Approach 1:
Multiple auxiliary cathode electrodes are electrically connected to the main cathode electrode through conductive vias, merging them into a unified electrical system. This merging approach allows the auxiliary electrodes to function collectively in improving brightness uniformity while maintaining a relatively simple electrical connection structure, avoiding the need for completely independent wiring for each auxiliary electrode.
Solution Approach 2:
Conductive vias serve as intermediary elements that electrically connect the auxiliary cathode electrodes to the main cathode electrode. These via structures provide a straightforward method for electrical connection, reducing the complexity that would otherwise arise from direct wiring between multiple electrodes and external circuitry.
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 design increases brightness uniformity by optimizing the electrical connections and light distribution within the display device.
Implementation Method 1
a light emitting layer, which emits light in response to application of voltage between the cathode and the anode
Implementation Method 2
a light conversion layer, which converts a wavelength of light emitted by the light emitting layer
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A display device (100) includes a cathode electrode (134a), a first anode electrode (130_1), a second anode electrode (130_2), a first light emitting layer (132_1) disposed between the cathode electrode (134a) and the first anode electrode (130_1), a first light conversion layer (170a) disposed above the first light emitting layer (132_1), a second light emitting layer (132_2) disposed between the cathode electrode (134a) and the second anode electrode (130_2), a second light conversion layer (170b) disposed above the second light emitting layer (132_2) and an auxiliary electrode (AE). The auxiliary electrode (AE) is electrically connected to the cathode electrode (134a), and a portion of the auxiliary electrode (AE) is between the first light conversion layer (170a) and the second light conversion layer (170b) in a top view direction (Z) of the display device (100).