Micro LED Panel Side-Bonding for Reusable Bonding Pads
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Solution Overview
Problem
Existing micro LED display panels face challenges with horizontal shifts during electrode bonding, leading to open or short circuits, and the existing front-bonding method makes it difficult to perform non-destructive removal and reuse of bonding pads.
Innovation Solution
The micro LED display panel employs a laterally connected micro LED structure to the bonding pad using the side contact surface of the electrode, allowing for partial melting and reuse of the bonding pad during laser trimming, without the need for additional space or re-manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If front bonding method is used to connect micro LED electrodes to bumps on substrate, then electrical connection is achieved, but horizontal shift occurs leading to open circuit or short circuit
Solution Approach 1:
The patent transitions from traditional front bonding (electrode bonding to bump top surface) to side bonding (electrode bonding to bump side surface). This dimensional change in bonding approach eliminates horizontal shift issues during bonding while maintaining electrical connection reliability.
Solution Approach 2:
Instead of bonding electrodes to the top surface of bumps (conventional approach), the patent inverts the bonding approach by connecting electrodes to the side surfaces of bumps, thereby avoiding alignment precision requirements and horizontal shift problems.
2Ease of repair
If laser trimming is applied to remove faulty micro LED using front bonding method, then micro LED can be removed, but bumps are melted and cannot be reused
Solution Approach 1:
The patent applies laser trimming locally to the side contact surface between electrode and bonding pad, rather than affecting the entire bonding pad. This localized approach allows selective removal of faulty micro LEDs while preserving the bonding pads for reuse.
Solution Approach 2:
The patent enables recovery and reuse of bonding pads after laser trimming by bonding faulty micro LEDs laterally to the side surface of bonding pads. The bonding pad material is not consumed or melted, allowing the same bonding pad to be reused for replacement micro LEDs.
3Ease of repair
If additional bumps are reserved on substrate for repair purposes, then faulty micro LED can be replaced, but pixel spaces are occupied reducing pixel density
Solution Approach 1:
The patent makes existing bonding pads multi-functional by enabling them to serve both initial micro LED connection and subsequent repair functions. The same bonding pad structure supports both normal operation and fault replacement without requiring dedicated repair bumps.
Solution Approach 2:
The bonding pad structure inherently provides repair capability through its side surface bonding design. The same bonding pad that connects the original micro LED can also connect replacement micro LEDs, making the system self-sufficient for repairs without external additional structures.
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 solution enables the reuse of bonding pads, optimizes pixel density by reusing the removed micro LED space, and reduces the risk of short circuits due to horizontal shifts during bonding.
Implementation Method 1
when the contact surface between the electrode and the bonding pad is irradiated (for example from the back of the driving substrate) by the laser to debond the faulty micro LED structure
Implementation Method 2
the bonding pad is only partially melted at the contact surface
Data Source
AI summary
A micro LED display panel is provided. The micro LED display panel includes a driving substrate and a plurality of bonding pads disposed on the driving substrate and spaced apart from each other. The micro LED display panel also includes a plurality of micro LED structures electrically connected to the bonding pads. Each micro LED structure includes at least one electrode disposed on the side of the micro LED structure facing the driving substrate. The electrode has a normal contact surface and a side contact surface. The normal contact surface faces the driving substrate, and the side contact surface is laterally connected to the corresponding bonding pad.