Tandem OLED Pixel Structure With Recessed Charge Layer Isolation
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Solution Overview
Problem
Tandem OLED display panels face pixel crosstalk issues due to lateral conduction of the charge generation layer, which affects the performance and accuracy of the display.
Innovation Solution
Incorporating a recess in the pixel defining layer between adjacent pixel units, where the charge generation layer is disconnected, and ensuring the cathode layer is continuous at the recess, preventing lateral charge conduction and maintaining normal pixel illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the charge generation layer is continuous across pixel units, then the manufacturing process is simple, but pixel crosstalk occurs due to lateral charge conduction
Solution Approach 1:
The charge generation layer is segmented into discrete portions, with each portion corresponding to a specific pixel unit. The layer is disconnected at recesses between adjacent pixel units, preventing lateral charge conduction while maintaining ease of manufacture through a simplified process that forms the charge generation layer in a single step across the entire display region.
Solution Approach 2:
The charge generation layer exhibits different properties in different locations: it is continuous within each pixel unit to enable proper charge generation, but disconnected at the recesses between pixel units to prevent crosstalk. This local variation in continuity is achieved through the recess structure in the pixel defining layer.
2Productivity
If the spacing between adjacent pixel units is reduced, then the aperture ratio increases, but charge leakage between pixels may occur
Solution Approach 1:
The solution moves from a two-dimensional planar structure to a three-dimensional structure by introducing recesses that extend vertically. The recesses create depth-based isolation between adjacent pixel units, allowing the charge generation layer to be disconnected in the vertical dimension while maintaining horizontal continuity within each pixel, thus preventing charge leakage even when pixel spacing is reduced.
3Object-generated harmful factors
If the charge generation layer is disconnected to prevent crosstalk, then pixel isolation is improved, but manufacturing complexity increases
Solution Approach 1:
The recess structure acts as an intermediary element that mediates between the charge generation layer and the pixel defining layer. By introducing this intermediate structural feature, the charge generation layer can be automatically disconnected at the recesses during a single formation process, achieving pixel isolation without increasing manufacturing complexity.
Data Source
AI summary
An organic electroluminescent display panel, a method of manufacturing the same, and a display device that can alleviate or avoid the occurrence of pixel crosstalk problems due to lateral conduction of the charge generation layer are disclosed. An organic electroluminescent display panel is provided which comprises: a substrate; an anode layer and a pixel defining layer over the substrate, the pixel defining layer defining pixel units, wherein a recess is provided in the pixel defining layer between adjacent pixel units; a stack of organic electroluminescent units over the anode layer and the pixel defining layer, the stack comprising at least two organic electroluminescent units and a charge generation layer disposed between organic electroluminescent units which are adjacent to each other; a cathode layer over the stack. The corresponding charge generation layers of the adjacent pixel units are disconnected at the recesses. The cathode layer is continuous at the recess.