Hybrid Display Cathode Layout to Prevent Micro-LED Short Circuits
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Solution Overview
Problem
Forming a common cathode through a full-surface deposition method results in short circuits with Micro-LED anodes, causing failure in hybrid display devices.
Innovation Solution
Incorporate an undercut groove in the driving backplane to disconnect the common cathode from the Micro-LED anodes, preventing electrical contact and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a full-surface deposition method is used to form the common cathode, then the production cost and production accuracy are improved, but the common cathode becomes short-circuited with the anodes of the Micro-LED chips, causing device failure
Solution Approach 1:
The patent divides the continuous common cathode into segmented regions by introducing undercut grooves that extend from the substrate surface through the common cathode layer. This segmentation prevents electrical short circuits between the common cathode and anodes while maintaining the overall common cathode structure for driving the display device.
Solution Approach 2:
The undercut groove acts as an intermediary barrier between the common cathode and the anodes of Micro-LED chips. By creating this intermediate structure, the patent prevents direct electrical contact that would cause short circuits, while still allowing the common cathode to function as intended.
2Ease of manufacture
If a full-surface deposition method is used to form the common cathode, then the manufacturing process is simplified, but short circuits occur between the common cathode and anodes, causing device failure
Solution Approach 1:
The continuous common cathode is segmented by undercut grooves that penetrate through it, creating isolated regions that prevent short circuits. This segmentation can be achieved through standard photolithography and etching processes, maintaining ease of manufacture while preventing device failure.
Solution Approach 2:
The undercut grooves are formed in advance before the common cathode is deposited, or the common cathode is patterned after deposition to create discontinuities. This preliminary structuring prevents short circuits from occurring during subsequent assembly and operation.
3Stability of the object's composition
If the common cathode is formed to cover the entire surface, then uniform electrical contact is achieved, but short circuits with anodes occur, reducing device yield
Solution Approach 1:
The common cathode is segmented into multiple isolated regions by undercut grooves, maintaining uniform electrical contact within each region while preventing short circuits with anodes. This segmentation approach preserves the beneficial uniform contact properties while eliminating the harmful short circuit effects.
Solution Approach 2:
The patent applies different structural properties to different regions: the common cathode maintains continuous coverage and uniform contact in most areas, while localized discontinuities are introduced at specific positions where undercut grooves are formed to prevent short circuits with anodes.
Data Source
AI summary
The present disclosure provides a hybrid display device. The hybrid display device includes: a driving backplane defined with an undercut groove; and a light-emitting structure layer including a first electrode layer, a common cathode, light-emitting elements, and first light-emitting units; the first electrode layer is electrically connected to a driving circuit layer; the first electrode layer includes first anodes, auxiliary cathodes, and second anodes, the undercut groove is adjacent to the first anodes, the common cathode is disconnected at the undercut groove, and a gap is defined between the common cathode and the first anodes.