Coaxial Multi-Color Micro-LED Stacking for Bright High-Resolution Pixels
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Solution Overview
Problem
Conventional LED display technologies face challenges in achieving high brightness and resolution simultaneously due to the opposite relationship between pixel size and brightness, and they require complex and inefficient fabrication processes for multi-color displays, leading to high power consumption and reliability issues.
Innovation Solution
A multi-color LED device with vertically stacked micro-LED structures using a common electrode for control currents, allowing for improved light illumination efficiency and reduced pixel footprint, along with direct bonding of LED structures to the substrate without intermediate substrates, enhancing fabrication efficiency and reliability.
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 improvement is limited
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 structures emitting different colors are stacked along the vertical axis, allowing them to occupy the same lateral footprint while maintaining distinct optical paths. This dimensional transition enables full-color display capability without sacrificing effective illumination area, as each LED layer contributes to the overall light output through vertical superposition rather than lateral separation.
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 vertically stacked within a single pixel footprint. Each LED layer is contained within the vertical space of the pixel, with smaller LED structures nested along the vertical axis. This nesting allows the pixel to maintain a small lateral dimension for high resolution while containing multiple light-emitting elements that collectively provide sufficient brightness through vertical light superposition.
3Ease of manufacture
If intermediate substrates are used for LED fabrication and transfer, then manufacturing flexibility is improved, but fabrication complexity and process time increase
Solution Approach 1:
The patent merges the LED fabrication process directly with the final substrate, eliminating the need for separate intermediate substrates. Multiple LED structures are fabricated in a integrated manner on the same substrate using a unified fabrication process, combining what would traditionally require separate fabrication and transfer steps. This merging approach reduces fabrication complexity and process time while maintaining manufacturing flexibility through direct integration.
4Adaptability or versatility
If multiple separate fabrication processes are used for different colored LEDs, then color quality can be optimized, but power consumption increases and reliability decreases
Solution Approach 1:
The patent implements a universal fabrication platform where a single integrated process can fabricate multiple LED structures of different colors on the same substrate. The fabrication methodology is designed to be color-agnostic, capable of producing red, green, blue, or other wavelength LEDs using the same process flow. This multi-functional approach maintains color quality optimization while reducing the number of separate processes, thereby improving reliability and reducing power consumption associated with multiple fabrication cycles.
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 solution improves brightness and resolution while reducing power consumption and simplifying the fabrication process, 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 method for fabricating a single pixel micro LED device for a display panel includes providing a substrate having a pixel driver and fabricating an LED structure layer stacked on top of the substrate. The method further includes bonding the substrate and the LED structure layer together by a bonding layer. The LED structure layer is electrically connected to the pixel driver via the bonding layer. In some embodiments, before bonding the substrate and the LED structure layer, the method includes coating a reflection layer on the LED structure layer. In some embodiments, the method includes patterning the LED structure layer to form a red light LED.