OLED Cathode Segmentation for Uniform Brightness
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Solution Overview
Problem
In OLED display technology, achieving high light transmission and electrical conductivity for the cathode layer is challenging, as thin cathodes result in high resistance and uneven voltage distribution, leading to increased power consumption and uneven brightness.
Innovation Solution
The implementation of an auxiliary cathode layer connected to the cathode layer in non-opening regions of pixels, spaced apart from the anode layer, enhances electrical conductivity without increasing cathode thickness, ensuring high light transmission and uniform brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the thickness of the cathode layer is reduced to achieve high light transmission, then light transmission is improved, but electrical conductivity deteriorates due to increased resistance
Solution Approach 1:
The cathode system is segmented into two distinct parts: a thin cathode layer (50-150 nm) in the opening region for high light transmission, and a thick auxiliary cathode layer (200-500 nm) in the non-opening region for low resistance. This segmentation allows each part to optimize its function independently, resolving the contradiction between light transmission and electrical conductivity.
Solution Approach 2:
Different thicknesses and positions are assigned to different regions of the cathode structure. The cathode layer in the opening region is thin to maximize light transmission, while the auxiliary cathode layer in the non-opening region is thick to minimize resistance. This local differentiation of quality allows simultaneous optimization of both light transmission and electrical conductivity across different spatial locations.
2Illumination intensity
If the thickness of the cathode layer is reduced to achieve high light transmission, then light transmission is improved, but voltage distribution becomes uneven across the cathode
Solution Approach 1:
The cathode is segmented into functional regions: the thin cathode layer in opening regions maintains high light transmission, while the thick auxiliary cathode layer in non-opening regions acts as a voltage redistribution network. This segmentation enables the system to maintain both high light transmission and uniform voltage distribution simultaneously.
Solution Approach 2:
The auxiliary cathode layer serves as an intermediary structure that receives current from the thin cathode layer and redistributes it across the pixel electrode. This intermediary thick cathode layer in the non-opening region ensures uniform voltage distribution while allowing the thin cathode layer in opening regions to maintain high light transmission.
3Reliability
If the thickness of the cathode layer is increased to improve electrical conductivity, then electrical conductivity is improved, but light transmission deteriorates
Solution Approach 1:
The cathode structure is segmented spatially so that the thick auxiliary cathode layer (200-500 nm) is located only in non-opening regions where light transmission is not required, while the thin cathode layer (50-150 nm) is located in opening regions to maximize light transmission. This segmentation allows the system to achieve both high electrical conductivity and high light transmission without compromise.
Solution Approach 2:
The cathode structure exhibits local quality differentiation: in non-opening regions, the cathode has high thickness (200-500 nm) for optimal electrical conductivity, while in opening regions, the cathode has low thickness (50-150 nm) for optimal light transmission. This local optimization resolves the contradiction by allowing different regions to have different properties suited to their specific functional requirements.
Data Source
AI summary
A display panel and a method of manufacturing a display panel are provided. The display panel includes an array substrate. The array substrate has a plurality of pixels. Each pixel includes an opening region and a non-opening region. An anode layer, a light emitting layer and a cathode layer are laminated in sequence in the opening region of the pixel. An auxiliary cathode layer and the cathode layer are laminated in sequence in the non-opening region of the pixel. The cathode layer in the opening region and the cathode layer in the non-opening region of the pixel are connected, and the auxiliary cathode layer is spaced apart from the anode layer. In this way, the cathode layer has high light transmission and good electrical conductivity, ensuring a better display effect.