LED Diffusion Covering with Refractive Index Mismatch
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Solution Overview
Problem
Existing LED lighting diffusers face challenges in achieving high light transmission and hiding power while minimizing particle loading, as they often compromise on either light transmission or hiding power due to the addition of scattering particles.
Innovation Solution
The development of a translucent, light-diffusing thermoplastic covering with carefully selected organic and inorganic particles, where the particle size, covering thickness, and refractive index mismatch between the organic particles and the polymer matrix are optimized to achieve high efficiency in light diffusion and hiding power with lower particle loadings, using a blend composition of thermoplastic polymer matrix, organic diffusing particles, and optional inorganic particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scattering particles are added to the cover to increase hiding power, then the light source shape is better masked, but light transmission is dramatically decreased
Solution Approach 1:
The patent changes the refractive index parameter of the scattering particles by selecting organic particles with refractive indices between 1.40-1.60 that are closer to the polymer matrix (1.49), thereby reducing light absorption and improving light transmission while maintaining hiding power. This parameter optimization allows the cover to achieve both high hiding power and acceptable light transmission without dramatic energy loss.
2Reliability
If particle loading is increased to improve diffusion and hiding properties, then light scattering is enhanced, but light transmission is reduced
Solution Approach 1:
The patent optimizes the particle size parameter to 0.5-10 microns and controls particle loading at 1-10% by weight, finding the optimal balance where sufficient diffusion is achieved without excessive particle loading that would block light transmission. This parameter optimization ensures high diffusion property while minimizing energy loss.
Solution Approach 2:
The patent uses moderate particle loading (1-10% by weight) rather than high loading, applying partial action to achieve the necessary diffusion effect without the excessive particle concentration that would dramatically reduce light transmission. This balanced approach maintains both diffusion property and light transmission.
3Use of energy by moving object
If conventional light sources are replaced with high luminous flux LEDs, then energy efficiency is improved, but directional illumination and harsh glare are created
Solution Approach 1:
The patent introduces a light-diffusing cover as an intermediary element between the LED light source and the environment. This cover contains scattering particles that redistribute the directional light from the LED, converting harsh direct illumination into soft, diffuse lighting while maintaining the energy efficiency benefits of LED technology and eliminating glare.
Solution Approach 2:
The patent converts the harmful directional illumination and glare produced by high-luminous-flux LEDs into beneficial soft, diffuse lighting by using the light-diffusing cover. The scattering particles in the cover transform the excessive directionality into desirable omnidirectional diffusion, turning the glare problem into a solution for comfortable lighting.
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 solution achieves a luminous transmission of greater than 40% and optical haze of greater than 95% with diffuse light scattering of greater than 85%, effectively reducing glare and providing a balanced light distribution without excessive particle loading, suitable for various LED lighting applications.
Implementation Method 1
The organic diffusing particles are refractive index mis-matched to the matrix polymer. The refractive index delta, and particle size are selected to provide a high efficiency (minimized particle loading).
Implementation Method 2
The organic diffusing particles are refractive index mis-matched to the matrix polymer. The refractive index delta, and particle size are selected to provide a high efficiency (minimized particle loading).
Implementation Method 3
Nano-sized ZnO inorganic particles may function as diffusion particles and optical brighteners as well as UV stabilizers.
Data Source
AI summary
The invention relates to high efficiency diffusion lighting coverings useful in LED lighting applications. The diffusing lighting coverings are made of organic diffusing particles homogeneously dispersed in a transparent polymer matrix. The primary organic diffusing particles are refractive index mis-matched to the matrix polymer. The refractive index contrast between the polymer matrix and diffusion particles, and particle size are selected to provide a high efficiency (minimized particle loading). The high efficiency diffusion coverings provides excellent light diffusion, high hiding properties and high light transmission. The secondary diffusion particles may optionally be added to further improve selected target properties of the covering. Nano-sized ZnO inorganic particles may also function as diffusion particles and optical brighteners as well UV stabilizers. Articles made of this translucent composition are useful in commercial and residential lighting, motor vehicle illumination (lights, panels), street lighting, displays and signs, desktop monitors, and LCD/LED TVs.