OLED Cathode Layer IR Drop Reduction via Parallel Conductive Pattern
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Solution Overview
Problem
Conventional OLED display panels experience non-uniform brightness due to IR drops in the cathode layer, resulting from resistance issues, which are not effectively addressed by existing technologies.
Innovation Solution
An OLED display substrate is designed with a conductive pattern connected in parallel to the cathode layer through via holes, reducing the equivalent resistance of the cathode layer and minimizing IR drops, while an insulation layer and specific hollowed-out regions in the conductive pattern enhance insulation and fingerprint identification functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional integral cathode layer is used, then the structure is simple, but non-uniform brightness occurs due to IR drops
Solution Approach 1:
The cathode layer is divided into multiple segments (first cathode layer and second cathode layer) with different work functions. The first cathode layer has a higher work function and the second cathode layer has a lower work function, allowing different regions to operate at different potentials to compensate for IR drops and achieve uniform brightness across the display panel.
2Device complexity
If the cathode layer is connected at one side only, then the connection is simple, but resistance issues cause non-uniform brightness
Solution Approach 1:
The cathode connection is extended from a single-point connection to a multi-dimensional network. The first and second cathode layers are connected to different potential electrodes through via holes distributed across the display region, creating a two-dimensional potential distribution that compensates for IR drops in various directions.
3Area of stationary object
If a narrower bezel is desired, then the display area can be increased, but the cathode connection structure becomes more constrained
Solution Approach 1:
The cathode connection is segmented into multiple independent pathways (first cathode layer connected to first potential electrode, second cathode layer connected to second potential electrode) that can be distributed across the bezel region, allowing flexible layout optimization to achieve narrower bezels while maintaining electrical connectivity.
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 prevents non-uniform brightness by reducing the IR drop to approximately 0V in the cathode layer, allowing for a narrower bezel and integrating fingerprint identification capabilities.
Implementation Method 1
The conductive pattern is arranged between the base substrate and the driving circuit layer and electrically connected to the cathode layer through a plurality of via holes
Implementation Method 2
subsequent to forming the conductive pattern including the first part and the second part, the method further includes oxidizing a portion of the conductive pattern at a boundary between the first part and the second part, so as to enable the first part to be insulated from the second part
Data Source
AI summary
An OLED display substrate, a manufacturing method thereof, and a display device are provided. The OLED display substrate includes a base substrate, a conductive pattern, a driving circuit layer, an anode layer, a light-emitting layer and a cathode layer. The driving circuit layer, the anode layer, the cathode layer and the light-emitting layer are arranged at a same side of the base substrate. The conductive pattern is arranged between the base substrate and the driving circuit layer and electrically connected to the cathode layer through a plurality of via holes.