Vertical Multi-Color Micro-LED Pixel Layout for Brightness and Resolution
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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 light crosstalk, inefficient light utilization, and complex fabrication processes, particularly in micro-LED displays for applications like AR and VR.
Innovation Solution
The integration of vertically stacked micro-LED structures with separate electrodes and a reflective cup structure to enhance light illumination efficiency, reduce pitch, and improve resolution, along with a micro-lens array to reduce divergence and viewing angle, enabling more efficient light use and better image quality.
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 and resolution improvement is limited
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of LEDs to a three-dimensional vertical stacking configuration. Multiple LED structures emitting different colors are stacked vertically along the z-axis, allowing colors to be combined in the vertical dimension rather than competing for horizontal space. This enables full color coverage while maintaining large effective illumination area at the pixel level.
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 positioned at different vertical levels, with lower LEDs supporting upper LEDs. This nesting approach allows multiple color-emitting structures to coexist within a compact vertical space, achieving full color capability without reducing the horizontal illumination footprint.
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 compensates for reduced pixel area by extending the light emission into the vertical dimension. Multiple LED structures stacked vertically generate cumulative light output, allowing smaller horizontal pixel footprints to achieve sufficient brightness through vertical light generation and extraction enhancement.
Solution Approach 2:
The patent merges multiple light-emitting structures vertically within a single pixel, combining their light output to achieve the required brightness level. The stacked LED structures work together as an integrated light source, with their combined luminous flux compensating for the reduced horizontal area of each pixel.
3Adaptability or versatility
If conventional fabrication methods are used with separate substrates for control circuitry and LEDs, then manufacturing flexibility is maintained, but the fabrication process becomes inefficient, costly, and unreliable
Solution Approach 1:
The patent integrates control circuitry and LED structures onto a single substrate, eliminating the need for separate substrate fabrication, transfer, and assembly processes. This monolithic integration approach streamlines manufacturing, improves reliability by reducing inter-substrate interfaces, and increases production efficiency while maintaining design flexibility.
Solution Approach 2:
The single substrate serves multiple functions: it acts as both the foundation for control circuitry and the support structure for vertically stacked LED structures. This multi-functional substrate design eliminates the need for multiple specialized substrates, simplifying the fabrication process and reducing manufacturing complexity.
4Ease of operation
If LCD or OLED displays are used, then convenient pixel control is achieved, but power consumption is high and battery operation time is limited
Solution Approach 1:
The LED-based display structures are self-emissive, generating their own light through electroluminescence without requiring external backlighting or complex driving circuits needed by LCDs. This self-service characteristic reduces power consumption significantly while maintaining efficient pixel control through direct current modulation of the LED structures.
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 improves brightness, resolution, and power efficiency, reducing light interference and waste, and simplifies the fabrication process, making it suitable for high-definition displays in AR, VR, and other applications.
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 reduce divergence and viewing angle
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 or 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.