Nanophosphor LED Structured Layers for Blue Light Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional phosphor converters in LEDs have low absorption cross-sections, require large volumes of phosphor particles, and suffer from back-scattering of blue pump light, leading to reduced efficiency and non-directional light emission.
Innovation Solution
Integration of meta-molecules with nanoparticles or photonic nanostructures within the LED's emitted light path, which increase light path length and absorption of blue pump light, enhancing scattering and local photonic density to improve color conversion efficiency and directivity of light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If phosphor particles are embedded in polymer films or solid media, then the phosphor converters can be deposited on the blue pump LED die, but the absorption cross-sections of the phosphor particles are low requiring a large number of phosphor particles and volume scattering agents
Solution Approach 1:
The patent changes the physical state of phosphor from traditional particles to nanophosphors with controlled size parameters (nanometer scale). This parameter change increases the absorption cross-section per unit volume, allowing sufficient light conversion with fewer particles and reduced need for scattering agents.
Solution Approach 2:
The patent uses composite structures by embedding nanophosphors within polymer matrices or solid media, creating a composite material system that combines the optical properties of nanophosphors with the mechanical properties of the host material, achieving both high absorption and structural integrity.
2Illumination intensity
If phosphor particles are used in large numbers, then the required converted light intensity and color point can be achieved, but significant amount of blue pump light is back-scattered back into the LED die leading to reduction in efficiency
Solution Approach 1:
The patent changes the size parameter of phosphor to nanoscale, which modifies the scattering characteristics. The small size reduces back-scattering of blue pump light into the LED die while maintaining sufficient absorption cross-section for effective wavelength conversion, thus reducing energy loss.
Solution Approach 2:
The patent converts the typically harmful back-scattering effect into a beneficial forward-scattering effect by using nanophosphors. The scattering that would normally send light back into the die is redirected forward, maintaining pump light efficiency while achieving sufficient conversion intensity.
3Illumination intensity
If phosphor particles require large number of volume scattering agents, then light scattering is improved, but the light angular spectrum becomes Lambertian which is not useful for directed or collimated light emission
Solution Approach 1:
The patent changes the size parameter to nanoscale, which fundamentally alters the scattering angular distribution. Nanophosphors produce less isotropic scattering compared to larger particles, enabling more directional light emission while maintaining sufficient scattering for uniform intensity distribution.
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 increases the absorption of blue pump light, reduces the amount of converter material needed, enhances light output, and allows for directional and collimated light emission, improving the overall efficiency and color point of LEDs.
Implementation Method 1
the plurality of nanoparticles configured to increase a light path length in the wavelength converting layer
Implementation Method 2
a photonic nanostructure configured to increase a light path length in the wavelength converting layer
Implementation Method 3
A typical phosphor converted, white LED uses phosphor converters to down-convert part of the blue pump light into other colors
Data Source
AI summary
A device comprising a light emitting diode (LED) substrate, and a meta-molecule wavelength converting layer positioned within an emitted light path from the LED substrate, the a meta-molecule wavelength converting layer including a plurality of nanoparticles, the plurality of nanoparticles configured to increase a light path length in the wavelength converting layer.