Display Device Filling Pattern Reduces Voltage Drop
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Solution Overview
Problem
Existing display devices face challenges in maintaining uniform voltage distribution and reducing power consumption, particularly due to high resistance in the cathode, which affects light emitting efficiency and display quality, especially in large-area cathodes.
Innovation Solution
A display device structure incorporating a conductive layer and a filling pattern with a conductive material of lower resistance than the cathode, where the filling pattern is connected to the conductive layer and overlaps both light emitting and non-light emitting areas, maintaining a cell gap between substrates without a separate spacer, thereby reducing voltage drops and enhancing uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional cathode structure is used in large-area display devices, then the device can be manufactured with standard processes, but high resistance in the cathode causes voltage drops and reduces light emitting efficiency
Solution Approach 1:
The cathode is divided into multiple segments: a first cathode layer (222) and a second cathode layer (224) with different materials and functions. The first layer provides basic conductivity while the second layer with lower resistance reduces voltage drops, particularly in large-area devices. This segmentation allows optimization of different regions for different functions.
Solution Approach 2:
The second cathode layer is selectively formed only in the non-light emitting area where low resistance is critical for reducing voltage drops. The light emitting area maintains its original cathode structure to preserve light emission properties. This local differentiation optimizes electrical performance without compromising optical performance.
2Manufacturing precision
If a separate spacer is used to maintain cell gap between substrates, then the cell gap can be precisely controlled, but the fabrication process becomes more complex with additional components
Solution Approach 1:
The filling pattern (206) is formed by combining the insulating layer (204) and conductive layer (205) into a single integrated structure that serves dual functions: maintaining cell gap and providing electrical connection. This eliminates the need for separate spacer components and simplifies the fabrication process while maintaining precise cell gap control.
Solution Approach 2:
The filling pattern performs multiple functions simultaneously: it maintains the cell gap between substrates, provides electrical connection between the common electrode and encapsulation layer, and prevents short circuits. This multi-functionality reduces the number of separate components needed in the device.
3Loss of energy
If the conductive layer is made thicker to reduce resistance, then voltage drops are reduced, but the cell gap increases and fabrication precision is compromised
Solution Approach 1:
The low-resistance conductive material is applied only in the non-light emitting area where resistance reduction is most critical for minimizing voltage drops. The light emitting area uses the standard cathode structure with appropriate thickness to maintain cell gap precision and optical performance.
Solution Approach 2:
The cathode uses a composite structure with two different conductive materials: the first cathode layer (222) with standard properties and the second cathode layer (224) with lower resistance. This composite approach allows optimization of electrical conductivity without compromising the precision of cell gap control.
Data Source
AI summary
A display device includes an organic electroluminescent area on the first base substrate, a second base substrate on the organic electroluminescent area and including a light emitting area and a non-light emitting area, a base layer between the organic electroluminescent area and the second base substrate, a conductive layer between the base layer and the organic electroluminescent area, and a filling pattern between the base layer and the conductive layer and overlapping a portion of the conductive layer. The conductive layer overlaps the light emitting area and the non-light emitting area, covers the filling pattern, and contacts the base layer. A portion of the conductive layer may contact the organic electroluminescent area. The filling pattern includes a first filling pattern having an insulating material and a second filling pattern on the first filling pattern. The second filling pattern has a conductive material with a lower resistance than the conductive layer.