Display Layer Misalignment Inspection Using Leakage Current Sensors
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Solution Overview
Problem
Display devices face defects due to misalignment of wirings and electrodes across different layers, leading to changes in element characteristics and potential defects, which existing technologies struggle to detect effectively.
Innovation Solution
A display device with a substrate, light-emitting elements, pixel circuits, sensors, and a leakage current detecting circuit, where sensors with conductive patterns spaced apart from the transistor channels detect leakage currents caused by misalignment, allowing for the determination of proper wiring placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple photo processes are performed using different photomasks for each layer to form wirings and electrodes on different layers, then the display device can achieve complex multi-layer wiring structures, but misalignment between layers may occur leading to wiring shifts from designed positions
Solution Approach 1:
The patent applies preliminary action by forming alignment marks and reference patterns on each layer before the actual wiring formation process. These pre-formed structures serve as guides to ensure proper alignment when multiple photomasks are used for different layers, preventing wiring shifts from their designed positions while enabling complex multi-layer structures
Solution Approach 2:
The patent uses alignment marks and reference patterns as intermediary elements between the photomasks and the actual wiring structures. These intermediaries facilitate precise alignment by providing visual or detectable references that guide the positioning of each layer relative to others, thereby maintaining manufacturing precision in complex multi-layer devices
2Manufacturing precision
If alignment marks are added to detect misalignment between layers, then layer positioning accuracy can be improved, but the device structure becomes more complex and additional manufacturing steps are required
Solution Approach 1:
The patent merges the alignment mark structures with the actual device structures by forming alignment marks using the same photomask patterns and material deposition processes as the functional wiring layers. This integration reduces overall device complexity by eliminating separate alignment mark fabrication steps while still providing necessary positioning accuracy
Solution Approach 2:
The patent creates multi-functional structures that serve both as functional wiring components and as alignment references. The same conductive patterns and electrode structures perform dual roles: enabling device operation and providing alignment detection capabilities, thereby avoiding additional structural complexity while improving positioning accuracy
Data Source
AI summary
The present disclosure relates to a display device, and the display device according to an embodiment includes: a substrate including a display area and a peripheral area; a plurality of light-emitting elements positioned in a display area; a plurality of pixel circuits connected to a plurality of light-emitting elements, respectively; a sensor positioned on the peripheral area of the substrate; a leakage current detecting circuit connected to the sensor; and a light emitting wiring connected to the leakage current detecting circuit and connected to at least one of the plurality of light-emitting elements, wherein the sensor includes a first sensor and the first sensor includes a first sensing transistor, and a first conductive pattern spaced apart from the channel of the first sensing transistor, and the first conductive pattern is positioned in the same layer as at least one of a plurality of layers configuring the transistor.