Organic Layer Island Alignment Detection in Display Devices
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Solution Overview
Problem
There is a need to accurately detect the alignment precision between organic layers and thin film transistor (TFT) layers in display devices with light-emitting elements, particularly for flexible displays where precise alignment is crucial for optimal performance.
Innovation Solution
The display device incorporates light-emitting elements with organic layers having island shapes, where a lower electrode overlaps with the edge of the organic layer without an insulating film, allowing for precise alignment inspection by measuring the positional relationship between the light-emitting regions and alignment marks on the TFT layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating film is provided between the lower electrode and the organic layer in light-emitting elements, then electrical insulation and device reliability are improved, but alignment precision detection becomes difficult
Solution Approach 1:
The patent divides light-emitting elements into two functional segments: display elements with insulating films for reliability, and inspection elements without insulating films for alignment detection. This segmentation allows both requirements to coexist in the same device.
Solution Approach 2:
The patent extracts the inspection function from the display function by creating dedicated inspection light-emitting elements that omit the insulating film layer, allowing alignment precision detection without compromising display element reliability.
2Productivity
If the frame region size is reduced to increase display area, then productivity and display area are improved, but alignment precision detection capability is lost
Solution Approach 1:
The patent applies local quality by placing inspection light-emitting elements with specific structural characteristics (no insulating film) in the frame region, while display elements maintain their complete structure. This allows alignment detection without expanding the overall device size.
Solution Approach 2:
The frame region is given dual functionality: it serves as both the structural border and as the location for alignment inspection elements. This multi-functionality allows alignment detection without sacrificing display area.
3Measurement precision
If inspection elements are added to enable alignment detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the inspection function into the existing light-emitting element structure by using the same basic components (electrodes, organic layer) but omitting only the insulating film, rather than adding entirely separate inspection mechanisms.
Solution Approach 2:
The inspection light-emitting elements are essentially copies of the display elements with one layer removed. This copying approach allows reuse of the proven light-emitting structure while creating the necessary inspection capability.
Data Source
AI summary
Included are first light-emitting element including a first organic layer having an island shape, and a first lower electrode, an electrode cover film having an insulating property and covering an edge of the first lower electrode, and a second light-emitting element including a second organic layer that has an island shape and that is an identical layer to the first organic layer, and a second lower electrode. As an opening of the electrode cover film wholly overlaps with the first lower electrode and the first organic layer, so that the opening defines a light-emitting region of the first light-emitting elements. When the edge of the second organic layer overlaps with the second lower electrode without being interposed with an insulating film, the edge of the second organic layer defines a light-emitting region of the second light-emitting element.