Micro-LED Assembly Hole Geometry for Precise Self-Alignment
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Solution Overview
Problem
The challenge of accurately aligning ultra-small semiconductor light emitting devices on a substrate during self-assembly is exacerbated by reduced dielectrophoresis force, leading to assembly defects such as tilting and separation, which can cause lighting defects in high-resolution display devices.
Innovation Solution
The design incorporates a substrate with assembly holes having an inner side with a first obtuse angle and the semiconductor light emitting devices with corresponding obtuse angles, along with a magnetic layer on the device's side portion to enhance magnetization and alignment, ensuring a larger separation margin and secure electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of light emitting devices is reduced to increase resolution, then productivity and cost are improved, but assembly precision deteriorates due to reduced dielectrophoresis force
Solution Approach 1:
The patent applies local quality by creating an asymmetric hole structure where the lower portion has a larger diameter than the upper portion. This local geometric variation provides enhanced support and alignment for ultra-small light emitting devices during self-assembly, compensating for the reduced dielectrophoresis force while maintaining overall device miniaturization for high resolution displays
Solution Approach 2:
The patent employs asymmetry by designing the hole with different diameters at its upper and lower portions. This asymmetric configuration creates a tapered structure that guides and stabilizes the light emitting device during insertion, ensuring accurate alignment and preventing tilting or separation despite the smaller device size and reduced assembly forces
2Quantity of substance
If the size of light emitting devices is reduced, then device density is improved, but assembly reliability deteriorates due to inaccurate alignment
Solution Approach 1:
The asymmetric hole structure with enlarged lower portion provides localized geometric features that enhance assembly reliability for ultra-small devices. The tapered configuration creates mechanical guidance and support at critical locations, ensuring stable alignment and connection even as device density increases through miniaturization
3Manufacturing precision
If the assembly hole diameter is reduced to match smaller devices, then manufacturing precision is improved, but assembly reliability deteriorates due to insufficient separation margin
Solution Approach 1:
The patent resolves this contradiction by applying local quality through asymmetric hole geometry. The upper portion maintains a smaller diameter for precise alignment, while the lower portion expands to provide adequate separation margin and mechanical support, thereby ensuring both alignment precision and assembly reliability simultaneously
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 configuration prevents assembly defects and lighting failures by ensuring accurate alignment and stable electrical connections, enabling high-resolution displays despite reduced device sizes.
Implementation Method 1
During self-assembly, a light emitting device 5 is assembled in the assembly hole 3 by a dielectrophoresis force
Implementation Method 2
During self-assembly, the light-emitting device 5 is moved to the assembly hole 3 by a magnetic field from a magnet, and the light-emitting device 5 is assembled in the assembly hole 3 by a dielectrophoresis force
Data Source
AI summary
The display device includes a substrate, a first and second assembly wirings on the substrate, a partition having a hole on the first and second assembly wirings, and a semiconductor light emitting device in the hole, wherein the hole configured to have an inner side with a first obtuse angle to a lower side, and wherein the semiconductor light emitting device configured to have at least one side having a second obtuse angle with respect to the lower side.