Micro LED Connection Pad Height for Chip Interference-Free Repair
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Solution Overview
Problem
The manufacturing process of micro LED display devices has limited flexibility due to the need for precise adjustment of the stepped shape or thickness of connection pads on the array substrate, which restricts the ability to address defects such as bright or dark spots after the substrate is formed, as existing techniques do not allow for sufficient degree of freedom in post-manufacturing adjustments.
Innovation Solution
The use of connecting members with varying thicknesses on the array substrate, where the second connecting member is thicker than the first, allowing for a greater distance from the substrate surface to the top of the connecting member, enabling the mounting of LED chips with different colors without interference and allowing for repair by forming a thicker repair connecting member for replacing defective LED chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the stepped shape or thickness of connection pad is adjusted by pixels during design or manufacturing stage, then interference between LED chips is avoided, but the degree of freedom in manufacturing process after forming array substrate becomes small
Solution Approach 1:
The connection pad structure is segmented into multiple layers: a first connection pad layer with uniform thickness for all pixels, and a second connection pad layer with varying thicknesses for different pixels. This segmentation allows the first layer to provide a standardized base structure while the second layer introduces pixel-specific thickness variations to prevent LED chip interference, thereby resolving the contradiction between avoiding interference and maintaining manufacturing flexibility.
2Manufacturing precision
If LED chips are mounted in adjacent pixels with very short distance, then display resolution is improved, but mounting members for subsequent LED chips may interfere with already mounted LED chips
Solution Approach 1:
The solution moves from two-dimensional planar adjustment to three-dimensional vertical adjustment by introducing varying thicknesses in the second connection pad layer. This dimensional change allows LED chips in adjacent pixels to be positioned at different heights, preventing interference during mounting while maintaining the short horizontal distances required for high display resolution.
3Reliability
If defects are repaired by replacing LED chip after manufacture, then reliability is improved, but it becomes difficult to avoid interference with surrounding LED chips
Solution Approach 1:
The connection pad structure is designed to be dynamically adaptable for repair operations. The varying thickness second connection pad layer can be selectively modified during repair to create sufficient vertical clearance for removing and replacing LED chips, while maintaining the original interference-prevention configuration for non-defective pixels. This dynamic adjustment capability enables reliable defect repair without compromising the overall structure.
Data Source
AI summary
An electronic device comprising: an array substrate having a first electrode and a second electrode; a first connecting member arranged on the first electrode; a first LED chip mounted on the first connecting member; a second connecting member arranged on the second electrode and being thicker than the first connecting member; and a second LED chip mounted on the second connecting member. A distance from a reference surface of the array substrate to a top surface of the second connecting member is larger than a distance from the reference surface to a top surface of the first connecting member.