Micro LED Pixel Stacking for Smaller Footprint and Bottom Routing
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Solution Overview
Problem
Traditional micro LED pixel structures face challenges in reducing dimensions while maintaining a large light emitting area, often requiring external panels for electrode connection which increases the pixel's dimensions.
Innovation Solution
The micro LED pixel design incorporates an integrated circuit (IC) backplane with three light emitting mesas staggered vertically, each connected to a bottom pad on the backplane, eliminating the need for an external panel and allowing for reduced cross-sectional dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If micro LED mesas are arranged side by side to form a micro LED panel, then the light emitting area is maintained, but the cross-sectional dimensions increase
Solution Approach 1:
The patent transitions from a two-dimensional side-by-side arrangement of micro LED mesas to a three-dimensional stacked configuration along the vertical direction. Multiple light emitting mesas are arranged at different heights above the IC backplane, utilizing the vertical dimension to accommodate multiple light emitting elements within a smaller horizontal footprint, thereby reducing cross-sectional dimensions while maintaining total light emitting area.
Solution Approach 2:
The patent implements a nested structure where multiple light emitting mesas are vertically stacked and interconnected through electrical connecting structures that pass through intermediate layers. Each mesa is positioned at a different height, with lower mesas supporting the structure for upper mesas, creating a nested hierarchical arrangement that maximizes space utilization and reduces the overall cross-sectional footprint.
2Area of stationary object
If external panels are used to connect electrodes for vertically stacked micro LED mesas, then the light emitting area is increased, but the overall dimensions of the micro LED pixel increase
Solution Approach 1:
The patent merges the electrode connection function directly into the vertical stacking structure by integrating electrical connecting structures within the pixel itself. The bottom electrical connecting structures connect lower mesas to the IC backplane, while top electrical connecting structures connect upper mesas, eliminating the need for separate external panels. This integration allows vertical stacking to achieve both increased light emitting area and reduced overall dimensions.
Solution Approach 2:
The patent introduces intermediate electrical connecting structures that serve as mediators between different height levels of light emitting mesas. These connecting structures transmit electrical signals and power between mesas at different vertical positions and to the IC backplane, enabling the vertically stacked configuration to function without external connection panels.
3Length of stationary object
If multiple light emitting mesas are stacked vertically, then the cross-sectional dimensions are reduced, but electrical connection complexity increases
Solution Approach 1:
The patent segments the electrical connection system into distinct bottom electrical connecting structures and top electrical connecting structures, each handling connections at specific height levels. This segmentation allows for modular design and simplifies the overall connection architecture by dividing the complex vertical interconnection task into manageable segments that can be independently designed and fabricated.
Solution Approach 2:
The electrical connecting structures in the patent serve multiple functions: they provide electrical connection between mesas at different heights, support the mechanical structure, and facilitate heat dissipation. This multi-functionality reduces the need for separate dedicated components, thereby simplifying the overall device complexity despite the vertical stacking configuration.
Data Source
AI summary
A micro LED pixel includes an integrated circuit (IC) backplane; a first light emitting mesa provided on the IC backplane; a second light emitting mesa provided above the first light emitting mesa, a part of the second light emitting mesa not covering the first light emitting mesa; a third light emitting mesa provided above the second light emitting mesa, a part of the third light emitting mesa not covering the first light emitting mesa or the second light emitting mesa; a first bottom electrical connecting structure configured to connect a bottom surface of the part of the second light emitting mesa and the IC backplane; and a second bottom electrical connecting structure configured to connect a bottom surface of the part of the third light emitting mesa and the IC backplane.