Display Device Charge Generation Layer Segmentation
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Solution Overview
Problem
Lateral leakage current in display devices, particularly in organic electroluminescent displays, is a challenge due to the ease of current flow through continuous layers, which affects the performance and efficiency of light emission.
Innovation Solution
A display device structure is implemented with multiple layers including a first layer separated from pixel electrodes, a second layer continuous over the electrodes, and a third layer interposed between them, where the third layer blocks carriers injected or transported by the second layer to reduce lateral leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a continuous charge generation layer is formed over the pixel electrodes, then the ease of manufacture is improved, but the lateral leakage current increases
Solution Approach 1:
The charge generation layer is divided into multiple independent sections, each corresponding to a pixel electrode. These sections are separated by insulating layers, preventing lateral current flow between adjacent pixels while maintaining continuous coverage over each pixel area. This segmentation resolves the contradiction by enabling easier manufacturing through continuous deposition processes while eliminating harmful lateral leakage through physical separation.
Solution Approach 2:
An insulating layer is introduced as an intermediary between the charge generation layer and the underlying structure. This insulating layer acts as a barrier that blocks lateral carrier transport between adjacent pixel regions while allowing vertical carrier injection from the pixel electrodes. The intermediary layer thus enables continuous charge generation layer formation while preventing harmful lateral current flow.
2Object-generated harmful factors
If the charge generation layer is formed in pieces to reduce lateral leakage current, then the lateral leakage current is reduced, but the device complexity increases
Solution Approach 1:
The charge generation layer is segmented into multiple sections corresponding to individual pixel electrodes. Each section is electrically isolated from adjacent sections by insulating layers, effectively reducing lateral leakage current. The segmentation is implemented in a systematic manner that maintains manufacturing simplicity while achieving the desired electrical isolation.
Solution Approach 2:
The insulating layers are selectively positioned only in the regions between adjacent pixel electrodes where lateral current flow occurs. The charge generation layer maintains continuous coverage and high quality over each pixel electrode area. This local application of insulation resolves the contradiction by addressing lateral leakage only where necessary without compromising the overall device structure or manufacturing simplicity.
3Ease of manufacture
If continuous layers are formed over and under the charge generation layer, then the ease of manufacture is improved, but the lateral leakage current increases
Solution Approach 1:
Insulating layers are introduced as intermediaries between the continuous charge generation layer and the underlying structures. These insulating layers selectively block lateral carrier transport pathways while allowing vertical carrier injection. The intermediary layers enable the formation of continuous charge generation layers for manufacturing simplicity while preventing harmful lateral leakage through strategic positioning at carrier transport interfaces.
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 structure effectively reduces lateral leakage current by blocking carriers, enhancing the display's efficiency and performance by preventing direct carrier flow between adjacent pixels.
Implementation Method 1
The third layer is adapted to block the carriers injected or transported by the second layer
Data Source
AI summary
A display device comprising: pixel electrodes; an electroluminescent layer composed of layers laminated with each other, the multiple layers including a light-emitting layer and a charge generation layer; and a counter electrode. The multiple layers include a first layer composed of sections separated from each other and overlapping with the pixel electrodes, a second layer in contact with the first layer and continuous over the pixel electrodes, and a third layer interposed between the first layer and the second layer, the third layer being in contact with the first layer and the second layer over an adjacent pair of the sections. At least the charge generation layer is the first layer. The second layer is adapted to inject or transport carriers, either electrons or holes. The third layer is adapted to block the carriers injected or transported by the second layer.