Nested RGB LED Package for Precise Micro-LED DEP Assembly
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Solution Overview
Problem
Current micro-LED display technologies face challenges in quickly and accurately transferring millions of semiconductor light emitting devices to large display panels, particularly in achieving high assembly rates and low transfer errors, due to non-uniform dielectrophoresis (DEP) forces and material heterogeneity between red (R), green (G), and blue (B) LED chips, which limits their use in UHD TVs, VR, and AR applications.
Innovation Solution
The semiconductor light emitting device package includes a first color LED chip with a GaN substrate, where a red LED is assembled on a GaN substrate, and then a green LED is patterned to create a green-red LED package, allowing simultaneous assembly with blue LEDs using magnetic and electrical power, ensuring homologous materials for precise DEP force control and reducing pixel size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If different shaped LED chips (circular for R, elliptical for G and B) are used to achieve shape exclusiveness, then assembly selectivity is improved, but the minimum chip size increases to at least 42 μm, which prevents reduction to micro-LED sizes (20 μm or less) required for UHD TVs, VR, AR, and XR applications
Solution Approach 1:
The patent uses the same circular shape for all R, G, and B LED chips instead of different shapes. This homogenizes the chip geometry, allowing size reduction to 20 μm or less while maintaining assembly selectivity through material-based differentiation (GaN substrate for R LEDs, AlGaInP substrate for G and B LEDs) rather than shape-based differentiation.
Solution Approach 2:
The patent changes the differentiation parameter from geometric shape to material composition. By using different substrate materials (GaN vs. AlGaInP) with distinct dielectric properties, the patent achieves assembly selectivity through material parameter differences rather than geometric parameter differences, enabling smaller chip sizes.
2Manufacturing precision
If heterogeneous materials (GaN for G and B LEDs, AlGaInP for R LED) are used to create material exclusiveness, then DEP force differentiation is improved, but assembly uniformity deteriorates due to non-uniform DEP forces acting on different materials simultaneously
Solution Approach 1:
The patent applies local quality by assigning different substrate materials to specific LED types: GaN substrate is used locally for R LEDs, while AlGaInP substrate is used locally for G and B LEDs. This localized material differentiation enables selective DEP force application to specific chip types during assembly, achieving both DEP force differentiation and assembly uniformity through spatially differentiated material properties.
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 approach increases the assembly probability and selectivity of R, G, and B LED chips, enabling their simultaneous assembly with reduced pixel size and improved assembly speed, suitable for UHD TV, VR, and AR applications.
Implementation Method 1
a self-assembly type transfer process using dielectrophoresis (DEP) has been attempted
Implementation Method 2
simultaneous assembly with blue LEDs using magnetic and electrical power
Data Source
AI summary
Discussed is a semiconductor light emitting device package for a display pixel The semiconductor light emitting device package can include a first semiconductor light emitting device of a first color having a first material and a second semiconductor light emitting device of a second color having a second material disposed on the first semiconductor light emitting device. The first semiconductor light emitting device can include a first semiconductor light emitting structure having an inner recess, and a first-first electrode and first-second electrode layer electrically connected to a first side and a second side of the first semiconductor light emitting structure, respectively. The second semiconductor light emitting device can be disposed in the inner recess of the first semiconductor light emitting device.