Contact Electrode Cathode Layout for Large-Panel IR Drop Reduction
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Solution Overview
Problem
The brightness uniformity of large-size display panels deteriorates due to nonuniform electrical properties of pixel circuits, increased wiring resistances and parasitic capacitances, and the IR Drop effect caused by voltage drops across the cathode layer.
Innovation Solution
A display panel design that includes an array substrate with an auxiliary electrode and a contact electrode patterned to directly pierce the light-emitting layer and connect with the cathode layer, reducing the resistance of the cathode layer and mitigating the IR Drop effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display panel size is increased to meet large screen demands, then the screen area is improved, but the brightness uniformity deteriorates due to increased wiring resistances and IR Drop effect
Solution Approach 1:
The cathode layer is divided into multiple segments by introducing contact electrodes that penetrate the light-emitting layer. Each contact electrode creates a localized low-resistance contact point, segmenting the cathode layer into multiple electrically connected regions. This segmentation reduces the overall resistance and improves current distribution uniformity across the large panel area.
Solution Approach 2:
The contact electrode extends in the vertical dimension by penetrating through the light-emitting layer from the cathode side to the anode side. This three-dimensional structure creates direct vertical electrical pathways, reducing the horizontal current path length and resistance in the cathode layer, thereby mitigating IR Drop effect in large panels.
2Illumination intensity
If the cathode layer resistance is reduced to minimize IR Drop effect, then the brightness uniformity is improved, but the device complexity increases due to additional contact electrode structure
Solution Approach 1:
The contact electrode serves multiple functions simultaneously: it acts as an electrical connection pathway for the cathode layer, serves as a structural support element, and functions as a current distribution uniformity optimizer. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.
Solution Approach 2:
The contact electrode structure merges the electrical connection function with the existing light-emitting layer and cathode layer structures. By integrating the contact electrode into the existing layered architecture rather than adding completely separate components, the overall device complexity is minimized while still achieving the resistance reduction goal.
3Ease of manufacture
If the organic light-emitting material covers the contact hole to enable inkjet printing manufacturing, then the manufacturing ease is improved, but the contact resistance between auxiliary electrode and cathode layer increases
Solution Approach 1:
The contact electrode acts as an intermediary element between the auxiliary electrode and the cathode layer. It provides a dedicated electrical pathway that is not blocked by the organic light-emitting material, thereby maintaining low contact resistance even when the organic material covers the contact hole area for inkjet printing manufacturing.
Solution Approach 2:
The contact electrode creates a localized region with different electrical properties (low resistance) within the contact hole area, while allowing the surrounding areas to be covered by organic light-emitting material for manufacturing purposes. This local quality differentiation ensures both manufacturability and electrical performance.
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 effectively reduces the IR Drop effect across the display panel, leading to improved brightness uniformity and overall display performance, especially in large-size panels.
Implementation Method 1
the contact electrode contacts the cathode layer through the light-emitting layer... effectively reduces the IR Drop effect... by decreasing the resistance of the cathode layer
Implementation Method 2
an auxiliary electrode may be provided, so that a resistance value is reduced by connecting a cathode layer with the auxiliary electrode in parallel
Data Source
AI summary
A display panel and a display device are disclosed. The display panel includes an array substrate, an electrode layer disposed on the array substrate, a light-emitting layer disposed on the electrode layer, and a cathode layer disposed on the light-emitting layer. The electrode layer includes an anode and a contact electrode disposed apart from each other on the array substrate. The contact electrode has a pattern, the contact electrode contacts the cathode layer through the light-emitting layer.