Xavier HUGON | Aledia: How do conventional micro-LEDs fundamentally limit augmented reality waveguide efficiency?
00:34 - 03:16
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Summary of the clip:
How do conventional micro-LEDs fundamentally limit augmented reality waveguide efficiency?
Adia's core technology involves growing Gallium Nitride (GaN) pillars directly on 200mm Silicon wafers without buffer layers, significantly reducing growth time from 5-7 hours to a maximum of 3 hours. This deep-tech approach enables low-cost, scalable manufacturing, with demonstrated first-meter working wafers in 2020, ensuring volume production readiness and compatibility with existing Silicon driver integration.
Augmented Reality (AR) micro-displays demand stringent specifications, including extremely high brightness, power efficiency, compactness, and high contrast. Traditional micro-LEDs face significant challenges when integrated with waveguides, primarily due to their quasi-Lambertian emission profile. This results in poor light injection efficiency, often less than 10%, necessitating larger micro-displays that compromise form factor or smaller micro-displays that suffer from a substantial drop in internal quantum efficiency (IQE).
In this short video, you can learn:
* GaN pillars grown directly on 200mm Silicon wafers.
* Reduced growth time and low-cost, scalable manufacturing.
* AR micro-display requirements: high brightness, power efficiency, compactness.
* Challenge: Low light injection efficiency (under 10%) of Lambertian micro-LEDs into waveguides.
* Consequence: Compromised micro-display size or reduced IQE.
#QuasiLambertianEmission, #LightInjectionEfficiency, #ARWaveguideEfficiency, #MicroLEDInternalQuantumEfficiency, #AugmentedReality, #GaNSemiconductors
This is a highlight of the presentation:
A new kind of microLEDs with built-in directive emission and RGB capability for power efficient AR microdisplays
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03:16 - 06:52
Can engineered photonic crystals precisely dictate the color and directionality of micro-LED emission?
Can engineered photonic crystals precisely dictate the color and directionality of micro-LED emission?
Adia has developed "photo-LEDs" by organizing nano-wires into photonic crystals, which fundamentally govern light emission through mode selection. Unlike random emission, these structured nanowires exhibit a distinct, bright emission peak. The emission wavelength is primarily controlled by the nanowire diameter, allowing for the creation of tricolor pixels by varying this parameter, with blue typically achieved using larger nanowires for improved manufacturability.
The design process involves first generating a resonance map, which correlates emission wavelength with parameters like pitch and wire density. Subsequently, an optical band diagram is computed to visualize band intensity relative to emission angle and wavelength. By superimposing the quantum well emission spectrum onto this diagram, precise control over emission angles and wavelengths is achieved, with strong correlation observed between modeling and experimental data, validating the design methodology for full micro-structures.
In this short video, you can learn:
* "Photo-LEDs" utilize organized nanowires forming photonic crystals.
* Photonic crystals control light emission through mode selection.
* Emission wavelength is tunable by nanowire diameter for tricolor pixels.
* Design involves resonance maps and optical band diagrams.
* Precise control over emission angle and wavelength demonstrated.
* Strong correlation between theoretical models and experimental results.
#PhotonicCrystals, #NanowireLEDs, #ModeSelection, #OpticalBandDiagrams, #MicroLED, #ARVRDisplays
08:32 - 13:06
What manufacturing and performance advantages do lithography-defined photonic crystals offer for next-generation micro-displays?
What manufacturing and performance advantages do lithography-defined photonic crystals offer for next-generation micro-displays?
Photonic crystal-based micro-LEDs offer significant advantages in manufacturability and stability. The emission wavelength is determined by lithography-defined photonic crystal structures rather than growth chamber conditions, leading to more robust and repeatable production. This approach also yields highly stable emission, with minimal wavelength shift due to temperature variations (thermal expansion and optical index changes) or current density fluctuations, exhibiting shifts as low as 2 nanometers over a 3x current density increase for blue pixels.
The localized nature of the emission field propagation, extending only to the first neighbor, enables very high Modulation Transfer Function (MTF) and allows for substantial pixel size reduction, with functional sub-pixels demonstrated with as few as five nanowires. This directional emission significantly boosts light injection into waveguides, with current prototypes achieving 80% of light within +/- 40 degrees and projections for up to 5x more light injection compared to Lambertian sources. Adia's 200mm Silicon fab, equipped with 1nm lithography and in-house hybrid bonding, is scaling production to 1 million micro-displays per week by 2030.
In this short video, you can learn:
* Improved manufacturability through lithography-defined wavelength.
* Enhanced emission stability against temperature and current density changes.
* High MTF and reduced pixel size due to localized emission.
* Significant increase in light injection efficiency into waveguides (up to 5x).
* 200mm Silicon fab with 1nm lithography and hybrid bonding.
* Projected production capacity of 1 million micro-displays per week by 2030.
#PhotonicCrystals, #LithographyDefined, #EmissionStability, #WaveguideCoupling, #MicroLEDs, #ARVR