Metasurface Side Mirrors for Micro-LED Side Light Redirection
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Solution Overview
Problem
Micro-LEDs in display panels suffer from significant side loss of light, leading to inefficiency, increased power consumption, and undesirable color mixing due to side-emitted light, which is not directed towards the observer.
Innovation Solution
Surround each micro-LED with a metasurface side mirror composed of nanoparticle metal that reflects side-emitted light orthogonally out of the dielectric layer towards the observer, preventing color mixing and improving light directionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If micro-LEDs are used to directly produce light for display pixels, then viewing angles and color saturation are improved, but significant side loss of light occurs leading to reduced efficiency and increased power consumption
Solution Approach 1:
The patent converts the harmful side-emitted light into a beneficial component by using a metasurface mirror to redirect it. The metasurface mirror reflects the side-emitted light at an angle that directs it toward the observer, transforming what was previously wasted energy into useful illumination that contributes to the display output.
Solution Approach 2:
The patent introduces a new spatial dimension for light management by placing a metasurface mirror at a specific angle (e.g., 45 degrees) relative to the micro-LED. This angular configuration enables the mirror to redirect side-emitted light from horizontal propagation to a direction that intersects with the observer's viewing path, effectively adding a dimensional transformation to light directionality.
2Loss of energy
If side-emitted light is allowed to propagate freely, then light efficiency is maintained, but color mixing occurs due to side-emitted light from adjacent pixels
Solution Approach 1:
The patent converts the harmful side-emitted light that causes color mixing into a beneficial element that enhances the desired pixel color. By using the metasurface mirror to redirect this light at a specific angle, the previously harmful side-emission is transformed into a useful contribution to the forward-directed light output, simultaneously reducing color mixing and improving efficiency.
Solution Approach 2:
The patent applies local quality by positioning the metasurface mirror specifically at the side of each micro-LED where color mixing occurs, rather than applying a universal solution across the entire display. The mirror is configured with a specific orientation (e.g., 45 degrees) that is optimized for redirecting side-emitted light from that particular location, providing localized correction for color mixing while maintaining overall light efficiency.
3Illumination intensity
If conventional mirrors are used to redirect light, then light directionality is improved, but manufacturing complexity and material loss increase
Solution Approach 1:
The patent employs composite materials by constructing the metasurface mirror from multiple dielectric layers with different refractive indices. This layered composite structure enables precise control over the phase and amplitude of reflected light, achieving superior light directionality and reduced scattering compared to simple metallic mirrors, while maintaining manufacturability through standard semiconductor fabrication processes.
Solution Approach 2:
The patent substitutes the conventional mechanical mirror structure with a metasurface-based optical system. Instead of using a bulky mechanical mirror that requires precise alignment and has high scattering losses, the invention uses a planar metasurface with sub-wavelength structures that can be fabricated using standard semiconductor processes, thereby reducing manufacturing complexity and improving light directionality through electromagnetic field control rather than mechanical reflection.
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
Enhances light efficiency by redirecting side-emitted light, reducing power consumption, and maintaining color fidelity and saturation while lowering operating temperatures.
Implementation Method 1
a metasurface side mirror composed of nanoparticle metal that reflects side-emitted light orthogonally out of the dielectric layer towards the observer
Data Source
AI summary
Methods and systems for improving the efficiency of an LED or micro-LED arrangement are described. In the disclosed embodiments, the LED or micro-LED is surrounded by an angled metasurface mirror, comprised of nanoparticles. This metasurface mirror reflect side emissions from the LED or micro-LED towards an observer, reducing light loss and thereby improving the energy efficiency of, as well as quality of light from, the LED or micro-LED. Other embodiments are described.