Micro-LED Assembly Substrate Structure for Uniform DEP Transfer
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Solution Overview
Problem
The self-assembly method for micro-LEDs in large-area displays faces issues with non-uniform DEP force leading to low assembly rates, weak assembly forces, and detachment of LED chips due to magnetic forces, particularly in the lower areas of assembly holes.
Innovation Solution
The assembly substrate structure includes first and second assembly electrodes with side assembly electrodes and bridge wirings, generating uniform DEP forces from the lower to upper areas of assembly holes, and side wirings that enhance electrical contact and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional self-assembly method using DEP force is used to transfer micro-LEDs, then transfer speed can be improved, but transfer error rate increases and assembly rate becomes low
Solution Approach 1:
The assembly electrode is segmented into multiple regions (first assembly electrode region, second assembly electrode region, third assembly electrode region) with different potentials, creating localized DEP force zones that guide micro-LEDs precisely into assembly holes while maintaining high transfer speed and accuracy
Solution Approach 2:
Different regions of the assembly electrode are assigned different electrical potentials to create non-uniform electric fields, generating localized DEP forces that concentrate at critical areas (assembly holes) to improve both transfer speed and positioning accuracy simultaneously
2Extent of automation
If DEP force is applied to assemble LED chips into assembly holes, then assembly process can be automated, but DEP force becomes non-uniform and assembly rate decreases
Solution Approach 1:
The system dynamically adjusts electric potentials across different assembly electrode regions during the self-assembly process, creating time-varying electric fields that maintain optimal DEP force distribution throughout the assembly holes, thereby preserving both automation and high assembly rate
Solution Approach 2:
The invention extends the DEP force application from a single-plane electrode to a three-dimensional electrode structure with multiple regions at different potentials, creating vertical and horizontal electric field gradients that ensure uniform DEP force distribution throughout the assembly holes
3Ease of operation
If magnet is used to move LED chips to assembly hole area, then transfer process can be achieved, but LED chips detach due to weak DEP force and magnetic force interference
Solution Approach 1:
The invention converts the harmful magnetic force that causes chip detachment into a beneficial positioning tool by using magnets to guide chips to the assembly area, while the enhanced DEP force from the multi-region electrode structure then secures the chips firmly in place, eliminating the detachment problem
Solution Approach 2:
The system applies preliminary magnetic force to guide chips to the assembly area, then immediately applies counteracting DEP force through the enhanced electrode structure to prevent detachment, creating a two-stage process that ensures both ease of operation and attachment stability
4Productivity
If DEP force is concentrated in lower area of assembly hole, then assembly can be achieved, but assembly force is reduced and assembly rate becomes low
Solution Approach 1:
The invention creates equipotential regions within the assembly holes by carefully designing the potential distribution across multiple electrode regions, ensuring that DEP force is uniformly distributed throughout the entire assembly hole volume rather than being concentrated only at the lower area, thereby maintaining strong assembly force and high assembly rate
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 structure significantly improves assembly rates and speeds by ensuring strong and uniform DEP forces, preventing LED chip detachment, and enhancing electrical contact for stable pixel operation.
Implementation Method 1
a self-assembly transfer process using dielectrophoresis (DEP) is being attempted in related technologies
Implementation Method 2
first moving the LED chip to the assembly hole area with the magnetic force of the magnet
Data Source
AI summary
The embodiment relates to an assembly substrate structure of a semiconductor light emitting device for a display pixel and a display device including the same. The assembly substrate structure of a semiconductor light emitting device for a display pixel according to the embodiment may include a first assembly electrode and a second assembly electrode disposed to be spaced apart from each other on a substrate, an assembly partition wall disposed on the first and second assembly electrodes with a predetermined assembly hole, and a first side assembly electrode or a second side assembly electrode electrically connected to the first assembly electrode or the second assembly electrode, respectively.