OLED Charge Generation Layer Segmentation for Leakage Control
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Solution Overview
Problem
In organic light emitting display devices, the charge generation layer (CGL) must be sufficiently thick to supply charges to neighboring organic emission layers, but excessive thickness can lead to electric current leakage into non-active areas, causing light leakage and color mixing between pixels, which degrades display quality.
Innovation Solution
The CGL is separated into active and non-active areas using partition layers with different opening widths, allowing for the formation of a dummy part with the same stack structure in non-active areas, minimizing current and light leakage without a separate patterning process, and adjusting the height of the partition layer to prevent disconnection between electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charge generation layer (CGL) is made thick to supply sufficient charges to organic emission layers, then charge supply capability is improved, but electric current leakage into non-active areas increases causing light leakage and color mixing
Solution Approach 1:
The patent divides the charge generation layer into multiple segments: a first charge generation layer in the active area and a second charge generation layer in the non-active area, separated by a partition layer. This segmentation prevents charge carriers generated in the non-active area from leaking into adjacent pixels, thereby eliminating light leakage and color mixing while maintaining sufficient charge supply capability in the active area through the first charge generation layer.
2Reliability
If the CGL is made thick to ensure sufficient charge supply, then emission reliability is improved, but device complexity increases due to additional partition structures
Solution Approach 1:
The partition layer serves multiple functions simultaneously: it physically separates the first and second charge generation layers to prevent charge leakage, provides structural support for the organic emission layers, and defines the boundary between active and non-active areas. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while ensuring emission reliability.
3Object-generated harmful factors
If partition layers are introduced to separate CGL into active and non-active areas, then light leakage is reduced, but manufacturing complexity increases due to additional patterning steps
Solution Approach 1:
The partition layer is formed in advance before depositing the organic emission layers and charge generation layers. By establishing the partition structure early in the manufacturing process, subsequent layers can be deposited conformally over the partition, simplifying the overall fabrication sequence and reducing the need for additional patterning steps that would otherwise be required to create separate charge generation layers in active and non-active areas.
Data Source
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AI summary
Disclosed is an organic light emitting display device (100) including an anode (140), a cathode (170), a plurality of organic layers and a partition member (131, 132). The plurality of organic layers is disposed between the anode (140) and the cathode (170), where at least one layer is separated to minimize current leakage into neighboring pixels. The partition member (131, 132)is disposed between the neighboring pixels and configured to separate the plurality of organic layers. The least one separated layer includes a charge generation layer (CGL). Because at least one layer is separated, current leakage into neighboring pixels can be minimized. Accordingly, defects resulting from light leakage and the mixing of colors of light from neighboring pixels may be reduced and display quality is enhanced.