Vertically Stacked RGB LED Display Using 2D Material Transfer
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Solution Overview
Problem
Conventional multicolor light-emitting diode (LED) displays face limitations in spatial resolution and color accuracy due to the parallel configuration of subpixels, which increases pixel size and compromises color mixing in the far field.
Innovation Solution
The method involves vertically stacking RGB thin film solid-state LEDs using a 2D material-based layer transfer process, allowing for the synthesis and stacking of individual LED layers emitting distinct colors, thereby increasing pixel density and color accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple LED subpixels are aligned in parallel configuration, then each subpixel can emit distinct wavelengths, but the pixel size increases and spatial resolution is limited
Solution Approach 1:
The patent transitions from a planar parallel arrangement of LED subpixels to a vertical stacked configuration. Multiple LED layers emitting different wavelengths (red, green, blue) are stacked along the vertical dimension, allowing color differentiation without increasing the lateral pixel footprint. This dimensional change enables higher pixel density while maintaining distinct color emission from each subpixel.
2Measurement precision
If multiple LED subpixels are aligned in parallel configuration, then each subpixel can emit distinct wavelengths, but color accuracy is compromised due to separate light paths
Solution Approach 1:
The patent merges the light paths of multiple LED subpixels by stacking them vertically within the same pixel location. The light from different wavelength LEDs passes through common optical paths and mixing layers, enabling precise color mixing and accurate color reproduction. This consolidation of light paths eliminates the color accuracy issues associated with separate parallel light paths.
3Manufacturing precision
If vertically stacked LED layers are implemented, then pixel density and color accuracy are enhanced, but fabrication complexity increases
Solution Approach 1:
The patent segments the fabrication process into distinct stages: individual LED layers are grown separately on different substrates, then transferred and stacked sequentially. Each LED layer can be independently optimized and fabricated using established techniques, reducing the complexity of simultaneous multi-layer fabrication. The segmentation approach allows for modular assembly and quality control at each stage.
Solution Approach 2:
The patent introduces release layers as intermediary elements between the LED layers and final substrate. These release layers facilitate the transfer and stacking process by providing temporary support and enabling controlled detachment. The intermediary release layers simplify the complex task of assembling vertically stacked LEDs by providing a manageable interface for layer transfer and positioning.
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 enhances pixel density, color accuracy, and mechanical strength, enabling applications in large-area outdoor displays, wearable displays, and solid-state lighting with reduced manufacturing costs.
Implementation Method 1
The first LED layer includes a first crystalline inorganic semiconductor and configured to emit light at a first wavelength
Implementation Method 2
The second LED layer includes a second crystalline inorganic semiconductor and configured to emit light at a second wavelength different than the first wavelength
Implementation Method 3
The third LED layer includes a third crystalline inorganic semiconductor and configured to emit light at a third wavelength different than the first wavelength and the second wavelength
Data Source
AI summary
A method of fabricating a multicolor light-emitting diode (LED) display includes forming a first LED layer on a first release layer comprising a first two-dimensional (2D) material disposed on a first substrate. The first LED layer is configured to emit light at a first wavelength. The method also includes transferring the first LED layer from the first release layer to a host substrate and forming a second LED layer on a second release layer comprising a second 2D material disposed on a second substrate. The second LED layer is configured to emit light at a second wavelength. The method also includes removing the second LED layer from the second release layer and disposing the second LED layer on the first LED layer.