Dual-Substrate OLED Conductive Layers for IR Drop Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In organic electroluminescent devices, the instability of electric current flowing through organic light emitting diodes due to IR drops along the power line leads to uneven brightness, which is difficult to control, and increasing the thickness of metal lines to stabilize current results in process complexities and structural issues like corrosion and peeling.
Innovation Solution
The use of two substrates with a first conductive layer on one and a second conductive layer on the other, electrically connected, allows for a lower resistance pathway for electric current to reach organic light emitting diodes, reducing IR drops and avoiding the structural issues associated with increasing metal line thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the metal layer is increased to reduce IR drop and stabilize electric current, then the uniformity of display voltage is improved, but the device complexity and manufacturing difficulty increase due to process time, cost, step coverage requirements, and structural stability issues
Solution Approach 1:
The power supply system is segmented into two separate conductive layers located on different substrates. The first conductive layer is on the first substrate and the second conductive layer is on the second substrate, which is positioned closer to the organic light emitting diodes. This segmentation allows each layer to have optimized thickness without compromising the other, reducing the need for excessively thick metal layers while maintaining current stability.
Solution Approach 2:
The solution moves from a single-plane thick metal layer approach to a three-dimensional dual-substrate configuration. By distributing conductive layers across two separate substrates in different spatial planes, the system achieves lower overall resistance without requiring any single metal layer to be excessively thick, thereby avoiding manufacturing complexities and structural issues.
2Reliability
If the thickness of the metal layer is increased to reduce electric resistance and IR drop, then the uniformity of display voltage is improved, but the manufacturing cost and process time increase
Solution Approach 1:
The conductive path is segmented into two separate layers on different substrates. Each layer can be manufactured with moderate thickness using standard process times, avoiding the need for single excessively thick layers that would require prolonged PVD or etching processes. The combined effect of both layers achieves the desired low resistance without extending manufacturing time.
3Reliability
If the thickness of the metal layer is increased to stabilize electric current, then the IR drop is reduced, but the structural stability deteriorates due to stress-induced peeling and incomplete sidewall coverage
Solution Approach 1:
The system is segmented into two separate conductive layers on different substrates, each with moderate thickness. This eliminates the need for single thick metal layers that generate excessive internal stress and are prone to peeling. The distributed structure improves structural stability while maintaining electrical performance.
Solution Approach 2:
The two substrates act as intermediaries that separate the conductive layers spatially. This separation allows each metal layer to be of manageable thickness with proper adhesion to its substrate, avoiding the stress concentration and peeling issues that occur in single thick-layer configurations.
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
This approach enhances the uniformity of display voltage, simplifies the manufacturing process, and maintains brightness consistency across pixel units without the drawbacks of increased metal line thickness.
Implementation Method 1
The second conductive layer is electrically connected to the first conductive layer, and then electrically connected to a voltage source by way of the first conductive layer. The electric current input from the voltage source can go to any one pixel unit by way of a lower resistant pathway selected from the first conductive layer and the second conductive layer.
Data Source
AI summary
An organic electroluminescent device comprises two substrates facing to each other. The first substrate has a first conductive layer and a pixel array. A second substrate is located on the pixel array, and has a second conductive layer on its lower surface. The pixel array includes a plurality of organic light emitting diodes connected to the first conductive layer. The second conductive layer is electrically connected to the conductive layer, and then electrically connected to a voltage source by way of the first conductive layer.