Segmented Common Electrode for Display Panel Luminance Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Top-emission display panels face issues with display unevenness and luminance unevenness due to the high resistance of the common electrode, which affects the potential distribution and light emission of the light-emitting elements.
Innovation Solution
The display panel incorporates a first and second common layer positioned over the pixel electrodes, with the common electrode overlapping with the pixel electrodes and the common layers. This configuration allows for a higher aperture ratio and reduces the voltage drop across the common electrode, thereby minimizing display and luminance unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a visible-light-transmitting conductive material is used for the common electrode to allow light extraction, then light transmission is improved, but the resistance of the common electrode increases causing voltage drop and luminance unevenness
Solution Approach 1:
The patent divides the common electrode into multiple segments (first common electrode and second common electrode) separated by insulating films. This segmentation allows each segment to be independently optimized for conductivity while maintaining light transmission properties, thereby reducing overall resistance and voltage drop while preserving luminance uniformity
Solution Approach 2:
The patent introduces auxiliary electrodes as intermediary elements between the pixel electrodes and the common electrode segments. These auxiliary electrodes help distribute electrical potential more evenly across the display surface, compensating for the high resistance of the transparent conductive material and reducing luminance unevenness
2Reliability
If the common electrode resistance is reduced to improve potential distribution, then luminance uniformity is improved, but the aperture ratio of pixels decreases
Solution Approach 1:
By segmenting the common electrode and using auxiliary electrodes, the patent achieves effective potential distribution with smaller conductive structures that occupy less pixel area, thereby maintaining high aperture ratio while ensuring luminance uniformity
Solution Approach 2:
The patent introduces a vertical dimension by stacking auxiliary electrodes and common electrode segments at different heights separated by insulating films. This three-dimensional arrangement allows for effective electrical connection and potential distribution without increasing the horizontal footprint within the pixel plane, thus preserving aperture ratio
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 proposed solution enhances the display quality by reducing display and luminance unevenness, increasing the aperture ratio of the pixels, and extending the lifetime of the light-emitting elements while maintaining high luminance.
Implementation Method 1
Light-emitting elements utilizing electroluminescence (also referred to as EL elements) have features such as ease of thinning and lightening, high-speed response to an input signal, and driving with a direct-current low voltage source
Data Source
AI summary
Display unevenness in a display panel is suppressed. A display panel with a high aperture ratio of a pixel is provided. The display panel includes a first pixel electrode, a second pixel electrode, a third pixel electrode, a first light-emitting layer, a second light-emitting layer, a third light-emitting layer, a first common layer, a second common layer, a common electrode, and an auxiliary wiring. The first common layer is positioned over the first pixel electrode and the second pixel electrode. The first common layer has a portion overlapping with the first light-emitting layer and a portion overlapping with the second light-emitting layer. The second common layer is positioned over the third pixel electrode. The second common layer has a portion overlapping with the third light-emitting layer. The common electrode has a portion overlapping with the first pixel electrode with the first common layer and the first light-emitting layer provided therebetween, a portion overlapping with the second pixel electrode with the first common layer and the second light-emitting layer provided therebetween, a portion overlapping with the third pixel electrode with the second common layer and the third light-emitting layer provided therebetween, and a portion in contact with a top surface of the auxiliary wiring.