Vertical Multi-Color Micro-LED Pixel Structure for High-Brightness Displays
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Solution Overview
Problem
Conventional LED display technologies face challenges in achieving high brightness and resolution while maintaining low power consumption, with issues such as inefficient light utilization, light crosstalk, and complex fabrication processes, particularly in micro-LED displays with large divergence angles and multi-color requirements.
Innovation Solution
The integration of vertically stacked micro-LED structures with separate electrodes and a reflective cup structure to enhance light illumination efficiency and reduce divergence, combined with a micro-lens array to improve viewing angle and reduce light interference, allowing for compact, high-resolution, and power-efficient display panels.
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 included within a pixel, but the effective illumination area within each pixel is reduced
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 horizontal footprint while maintaining color separation. This dimensional transition enables full-color display within a single pixel area without reducing the effective illumination area, as all LEDs emit light through the same optical path.
Solution Approach 2:
The patent implements a nested structure where multiple LED structures are vertically stacked and integrated within a single pixel unit. Each LED structure is nested along the vertical axis, with lower LED structures serving as foundations for upper ones. This nesting approach allows multiple color-emitting components to coexist within a compact vertical space, achieving full-color capability while maintaining a small pixel footprint and maximizing illumination area.
2Manufacturing precision
If pixel size is reduced to achieve high resolution, then more pixels can be fitted in the display, but brightness per pixel decreases
Solution Approach 1:
The patent changes the structural parameter of LED arrangement from horizontal separation to vertical stacking. This parameter change allows multiple color-emitting LEDs to occupy the same horizontal space, effectively increasing the light output area without increasing the pixel footprint. The vertical stacking enables each pixel to maintain adequate brightness by incorporating multiple LED structures that all contribute to the total light emission from the pixel.
Solution Approach 2:
The patent creates a composite multi-LED structure within each pixel, combining multiple LED structures with different color emissions in a vertical stack. This composite structure integrates red, green, and blue LED structures along with optical elements like reflective cups and microlenses to form a unified pixel unit that delivers high brightness across all colors while maintaining small pixel dimensions for high resolution.
3Ease of manufacture
If conventional fabrication methods with separate substrates are used, then LEDs can be transferred to control circuitry substrate, but the process is inefficient, costly and not reliable
Solution Approach 1:
The patent merges the LED fabrication process with the control circuitry substrate integration by forming multiple LED structures directly on the same substrate that contains the control circuitry. This eliminates the need for separate substrate fabrication, transfer, and assembly processes. The unified substrate approach combines LED structures, control circuitry, and optical elements into a single integrated device, dramatically improving fabrication efficiency and reliability while reducing manufacturing complexity and cost.
4Volume of moving object
If micro-LED structures are used with large divergence angles, then compact pixel size is achieved, but light crosstalk between adjacent pixels increases
Solution Approach 1:
The patent introduces optical intermediary elements including reflective cups and microlenses positioned between the LED structures and the external environment. The reflective cups collect and redirect light from the LEDs, while microlenses focus and direct the light output. These intermediary optical elements control the light emission pattern, reducing divergence angles and confining light to specific angular ranges that minimize crosstalk between adjacent pixels while maintaining compact pixel dimensions.
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 significantly enhances light emission directionality, reduces power consumption, and improves image quality by increasing brightness and contrast, while simplifying the fabrication process and eliminating substrate-related reliability issues.
Implementation Method 1
a first reflective structure is formed on a bottom of the first light emitting layer... a second reflective structure is formed on a bottom of the second light emitting layer
Implementation Method 2
a micro-lens array to improve viewing angle and reduce light interference
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. Light from the micro multi-color LED device is emitted substantially vertically upward through each of the LED structures. In some embodiments, each LED structure is connected to a pixel driver and/or a common electrode. The LED structures are bonded together through bonding layers. In some embodiments, planarization layers enclose each of the LED structures or the micro multi-color LED device. In some embodiments, one or more of reflective layers, refractive layers, micro-lenses, spacers, and reflective cup structures 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.