Micro LED Displays with Mie and Rayleigh Scattering Particles
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Solution Overview
Problem
Micro LED displays face challenges with high power consumption due to total internal reflection, leading to reduced light extraction efficiency and shorter battery life in portable electronics.
Innovation Solution
Incorporating light scattering particles of different sizes and refractive indices on micro LED surfaces, such as Mie and Rayleigh scattering particles, to reduce total internal reflection and enhance light extraction efficiency, along with the use of nanoparticles on nanowire or nanopyramid LEDs to create subwavelength textures for improved light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If micro LED displays use conventional smooth surfaces, then manufacturing is simple, but light extraction efficiency is low due to total internal reflection
Solution Approach 1:
The patent changes the surface parameters of the micro LED by introducing particles with different refractive indices and sizes. This modifies the optical parameters (refractive index distribution) to reduce total internal reflection and improve light extraction efficiency without fundamentally changing the manufacturing process
Solution Approach 2:
The patent introduces intermediary particles (with refractive indices between the LED material and air) as mediators at the LED surface. These particles act as optical intermediaries that facilitate light extraction by reducing the abrupt refractive index mismatch, thereby decreasing total internal reflection
2Loss of energy
If light scattering particles are added to improve light extraction, then light extraction efficiency increases, but device complexity increases
Solution Approach 1:
The patent optimizes particle parameters (size, refractive index, concentration) to achieve effective light scattering with minimal added complexity. By carefully selecting particle characteristics that match the LED emission wavelength, the patent maximizes light extraction improvement while minimizing structural complexity
Solution Approach 2:
The patent uses inexpensive, easily applicable particle coatings that can be deposited using simple processes. These particle layers are thin and can be applied as disposable coatings rather than requiring complex integrated structures, thus limiting the increase in device complexity
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 results in approximately 2× higher light extraction efficiency compared to state-of-the-art OLED displays and GaN-based nanowire LEDs, significantly reducing power consumption and extending battery life in mobile devices.
Implementation Method 1
Each of the micro light emitting diode devices have Mie scattering particles thereon
Implementation Method 2
The binder material layer has a plurality of Rayleigh scattering particles therein
Data Source
AI summary
Micro light-emitting diode displays and methods of fabricating micro LED displays are described. In an example, a micro light emitting diode pixel structure includes a plurality of micro light emitting diode devices in a dielectric layer. Each of the micro light emitting diode devices have Mie scattering particles thereon. A transparent conducting oxide layer is above the dielectric layer and on the Mie scattering particles. A binder material layer is above the transparent conducting oxide layer. The binder material layer has a plurality of Rayleigh scattering particles therein.