Micro-LED Racetrack Sub-Pixels for Higher Color Purity
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Solution Overview
Problem
Micro-LED panels face challenges in color purity due to broad band spectrum emission and reduced brightness from integrated polarizers, compromising display quality.
Innovation Solution
A sub-pixel structure with angled sub-pixel isolation structures and a color conversion material, including quantum dots, is used, along with a filter layer and micro-lenses to enhance light emission efficiency and utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If quantum dot color conversion materials are used with broad band spectrum LED emission, then color conversion is achieved, but color purity is compromised
Solution Approach 1:
The patent applies local quality by creating distinct wells with specific aspect ratios for different color sub-pixels. Each well is locally optimized with tailored dimensions to control light propagation paths and maximize quantum dot interaction for specific color conversions, thereby achieving high color purity for each individual color channel while managing the broad band spectrum input.
Solution Approach 2:
The patent introduces a vertical dimension through the well structure with optimized aspect ratios. By controlling the depth-to-width ratio of the wells, the patent extends the light interaction path from a two-dimensional surface to a three-dimensional volume, enabling enhanced color conversion efficiency and purity without increasing the lateral footprint.
2Illumination intensity
If polarizers are integrated with quantum dots to improve color conversion, then color accuracy is enhanced, but brightness of RGB transmission is reduced
Solution Approach 1:
The patent extracts the polarizer from the traditional integrated position and replaces it with a reflective well structure. By removing the polarizing element and using total internal reflection at the well boundaries instead, the system maintains color accuracy through controlled light paths while eliminating the brightness loss associated with polarizer absorption.
Solution Approach 2:
The patent converts what would normally be wasted light (broad band spectrum emission that doesn't match quantum dot absorption) into a beneficial effect by using the well structure to trap and redirect this light multiple times through the quantum dot layer, enhancing color conversion efficiency while maintaining overall brightness.
3Productivity
If sub-pixel isolation structures are designed with optimized aspect ratios, then color conversion efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the display into discrete sub-pixels, each containing a well with optimized aspect ratio. This segmentation allows independent optimization of each well's dimensions for maximum color conversion efficiency while maintaining a modular structure that can be manufactured using standard pixel array fabrication processes.
Solution Approach 2:
The patent optimizes the geometric parameters of the wells, specifically the aspect ratio (depth-to-width), to maximize light trapping and quantum dot interaction. By carefully selecting and controlling these dimensional parameters during fabrication, the patent achieves high color conversion efficiency without requiring complex additional structures or materials.
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 color conversion efficiency and reduces light loss, resulting in enhanced display quality and brightness by optimizing the aspect ratio of the sub-pixel wells and utilizing reflection materials to increase quantum dot interaction.
Implementation Method 1
a color conversion material disposed over the micro-LED within the well
Implementation Method 2
utilizing reflection materials to increase quantum dot interaction
Implementation Method 3
disposing a plurality of micro-lenses over the filter layer and over each of the plurality of wells
Data Source
AI summary
Embodiments of the present disclosure generally relate to LED pixels and methods of fabricating LED pixels. The pixel includes a plurality of sub-pixels. Each sub-pixel includes a backplane comprising a top surface, a plurality of sub-pixel isolation structures disposed over the backplane, a micro-LED disposed in the well, a color conversion material disposed over the micro-LED within a well, and a filter layer disposed over the sub-pixel isolation structures and the color conversion material. The sub-pixel isolation structures defining the well. The sub-pixel isolation structures include sidewalls and a top surface. The sidewalls are angled at an angle from the top surface of the backplane to the top surface of the sub-pixel isolation structures.