Light Diffusing Polymer Composition for LED Glare Reduction

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Solution Overview

Problem

Current LED diffusers lead to light transmission loss and fail to adequately control light color and temperature, resulting in harsh glare and inefficient lighting solutions.

Innovation Solution

A light diffusing polymer composition comprising a matrix polymer blended with diffuser polymer particles characterized by specific size distribution, crosslinking level, and refractive index, along with performance additives, to achieve high light transmission and controlled diffusivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional LED diffusers (inorganic particles or organic beads) are used to scatter light, then light diffusion is achieved, but light transmission loss increases significantly

Engineering Contradiction:
Improvelight diffusionVSAvoidlight transmission loss
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The invention changes the refractive index parameter of the diffuser particles to match the matrix polymer (both set to 1.55), eliminating refractive index mismatch that causes light transmission loss. This allows adequate light diffusion while maintaining high light transmission efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite system consisting of matrix polymer (polycarbonate or polymethylmethacrylate) blended with diffuser polymer particles. The composite achieves both light diffusion functionality and high light transmission by carefully selecting materials with matched optical properties.

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If conventional diffusers are used to provide even illumination, then glare is reduced, but control over light color and temperature is lost

Engineering Contradiction:
Improveeven illuminationVSAvoidlight color and temperature control
Core Design Contradiction:
Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The invention applies local quality by incorporating performance additives specifically within the diffuser particles rather than uniformly throughout the matrix. This localized approach allows customization of light properties (color, temperature) in specific regions while maintaining overall diffusion functionality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention enables parameter changes by allowing adjustment of refractive index, particle size, and additive composition to control light color temperature and color rendering while maintaining diffusion performance.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If light diffusing beads are added to LED packaging, then light scattering is improved, but light transmission efficiency decreases

Engineering Contradiction:
Improvelight scatteringVSAvoidlight transmission efficiency
Core Design Contradiction:
Illumination intensityVSProductivity

Solution Approach 1:

The invention optimizes the refractive index parameter to match between diffuser particles and matrix polymer, minimizing light transmission loss while maintaining adequate scattering. The particle size parameter is also optimized to balance diffusion and transmission.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention achieves homogeneity in refractive index between the matrix polymer and diffuser particles, reducing optical interfaces that cause transmission loss. This homogeneous optical property allows efficient light transmission while maintaining diffusion functionality.

Inventive Principle:
Principle #33Homogeneity

4Illumination intensity

If inorganic particles like TiO2 are used as scattering media, then light diffusion is achieved, but fire resistance and optical control are compromised

Engineering Contradiction:
Improvelight diffusionVSAvoidfire resistance and optical control
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The invention uses organic polymer-based diffuser particles instead of inorganic particles, combining fire-resistant matrix materials with polymer diffusers that offer better optical control and color stability while maintaining adequate light diffusion.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes from inorganic to organic diffuser materials, enabling better control over optical parameters such as refractive index, color rendering, and fire resistance through polymer chemistry selection.

Inventive Principle:
Principle #35Parameter changes

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

The solution provides improved light distribution, reduced glare, and enhanced efficiency while allowing for customizable refractive index and color control, addressing the limitations of existing LED diffusers.

Implementation Method 1

light scattering particles or embossing are currently used to diffuse the LED light

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

refractive index depending on the application and device

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentUS11156746B2Light diffusing polymer composition, method of producing the same, and articles made therefrom
Publication Date: 2021.10.26 ROHM & HAAS CO

AI summary

A composition comprising: a blended product of: a matrix polymer; and from 0.05 to 2.5 wt % diffuser polymer particles, wherein the diffuser polymer particles are characterized by an average diameter from 2 to 20 micrometers, a particle size distribution such that at least 90 wt % of the polymer particles fall within ±30% of the volume average particle size, a crosslinking level greater than 4%; and wherein the diffuser polymer particles comprise units derived from at least one alkyl(meth)acrylate monomer, from 5 wt % to 25 wt % units derived from a crosslinking monomer selected from the group consisting of aliphatic crosslinking monomers, aromatic crosslinking monomers and combinations thereof, optionally, units derived from one or more comonomers selected from the group consisting of aryl(meth)acrylate monomers and monovinyl arenes; and wherein from 0.1 to 20 wt % one or more performance additives dispersed within the diffuser polymer particles is provided.