Coaxial Multi-Color LED Stacking for High-Resolution Bright Pixels
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Solution Overview
Problem
Conventional LED display technologies face challenges in balancing pixel size, resolution, and brightness, particularly in achieving high brightness while maintaining high resolution and efficient power consumption, and existing fabrication methods for multi-color displays are inefficient and unreliable.
Innovation Solution
A multi-color LED device structure with vertically stacked LED layers, utilizing a common electrode for control currents, and a substrate directly bonded to the LED structures without intermediate substrates, enhancing light illumination efficiency and resolution within a single pixel area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate monochromatic LEDs are fabricated at different non-overlapping zones within the pixel area, then multiple colors can be achieved, but the effective illumination area within each pixel is reduced and resolution is compromised
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of separate monochromatic LEDs to a three-dimensional vertically stacked configuration. Multiple LED layers (red, green, blue) are stacked along the vertical axis, allowing each LED type to occupy its own layer while maintaining overlapping lateral boundaries. This vertical stacking enables full-color reproduction without sacrificing pixel area, as each LED layer can extend across the entire pixel footprint rather than being confined to non-overlapping zones.
2Manufacturing precision
If pixel size is reduced to achieve high resolution, then more pixels can be displayed, but brightness per pixel decreases
Solution Approach 1:
The patent implements a nested structure where multiple LED layers are stacked within a single pixel volume. Each LED layer (red, green, blue) is nested vertically within the same lateral footprint, creating a compact three-dimensional arrangement. This nesting allows the pixel to maintain a small lateral dimension for high resolution while incorporating multiple light-emitting elements vertically, thereby preserving or enhancing total light output despite reduced pixel size.
3Ease of manufacture
If conventional fabrication methods with intermediate substrates are used, then LED transfer is possible, but the process is inefficient, costly and not reliable
Solution Approach 1:
The patent extracts and eliminates the intermediate substrate step from the conventional LED fabrication process. Instead of transferring LEDs through multiple substrates (original substrate → intermediate substrate → final substrate), the invention directly bonds the vertically stacked LED structure to the final substrate. This extraction of the intermediate step simplifies the fabrication workflow, reduces process complexity, lowers costs, and improves reliability by removing an unnecessary transfer operation.
4Illumination intensity
If vertically stacked LED layers are implemented, then brightness and resolution are improved simultaneously, but device structure complexity increases
Solution Approach 1:
The patent merges multiple LED structures into a single integrated vertically stacked unit. Instead of treating red, green, and blue LEDs as separate components requiring individual control and mounting, the invention combines them into one cohesive three-dimensional structure where all LED layers share common bonding interfaces and lateral boundaries. This merging reduces the number of discrete components and simplifies the overall device architecture, making the complex multi-color LED system more manageable and manufacturable.
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
The multi-color LED device improves brightness and resolution simultaneously, reduces pixel footprint, and enhances fabrication efficiency and reliability, making it suitable for high-definition AR and VR applications.
Implementation Method 1
two or more LED structure layers that include: a first LED structure layer stacked on top of the substrate; and a second LED structure layer stacked on top of the first LED structure layer
Data Source
AI summary
A micro multi-color LED device includes two or more LED structures for emitting a range of colors. The two or more LED structures are vertically stacked to combine light from the two more LED structures. In some embodiments, each LED structure is connected to a pixel driver and a shared P-electrode. The LED structures are bonded together through bonding layers. In some embodiments, reflection layers are implemented in the device to improve the LED emission efficiency. A display panel comprising an array of the micro tri-color LED devices has a high resolution and a high illumination brightness.