LED Encapsulant Bead Dispersion for Uniform Color Mixing
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Solution Overview
Problem
Light-emitting diodes (LEDs) with multiple color elements suffer from non-uniform color distribution and reduced light intensity when viewed from different angles, affecting applications like spotlights and medical illumination, where high color rendering index (CRI) is crucial.
Innovation Solution
A light-emitting device with a transparent matrix material encapsulating the LEDs, containing beads with a higher refractive index than the matrix, which scatters and mixes light to provide uniform color and intensity over a wide range of angles, improving CRI and light efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a secondary lens with light mixing design is used to compensate for non-uniform color distribution, then color uniformity is improved, but light intensity output is reduced by 40% to 50%
Solution Approach 1:
The patent changes the optical parameters of the encapsulant material by incorporating beads with different refractive indices (e.g., TiO2 beads with refractive index of 2.5-3.0 in a silicone matrix with refractive index of 1.4-1.6). This parameter change enables effective light scattering and mixing without the need for secondary lenses, thereby maintaining high light intensity output while achieving uniform color distribution across wide viewing angles.
2Adaptability or versatility
If multiple monochromatic LED elements are used to produce white light, then color balance can be adjusted, but non-uniform color distribution occurs when viewed from different angles
Solution Approach 1:
The patent introduces beads as an intermediary scattering medium within the encapsulant. These beads (e.g., TiO2, SiO2, or ZrO2) with refractive indices higher than the matrix material act as mediators to scatter and mix light from multiple LED elements. This intermediary scattering mechanism randomizes the light paths and ensures uniform color distribution across all viewing angles, while preserving the ability to adjust color balance through independent LED element control.
3Use of energy by moving object
If phosphor concentration is carefully controlled to produce white light, then light conversion efficiency is improved, but color non-uniformity persists depending on viewing angle
Solution Approach 1:
The patent creates a composite encapsulant material consisting of a base matrix (e.g., silicone, epoxy, or polymer with refractive index 1.4-1.6) combined with dispersed beads (e.g., TiO2, SiO2, or ZrO2 with refractive indices 2.5-3.0). This composite structure provides both the light conversion functionality of phosphors and the light scattering/mixing capability of the beads, achieving uniform color distribution while maintaining efficient light conversion from the LED elements.
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 achieves 30% or greater luminosity per LED die compared to devices with secondary lenses, providing uniform color and high CRI over a wide range of angles, enabling more efficient and effective LED-based light sources and displays.
Implementation Method 1
The transparent matrix material includes a dispersion of beads configured to scatter the light emitted by the LED elements as the light traverses the matrix material
Implementation Method 2
The beads have a second refractive index different than the first refractive index
Data Source
AI summary
A light-emitting device has a light source disposed on a support. A matrix material including a dispersion of beads is disposed over the light source. The refractive index of the beads is different from the refractive index of the matrix material. The light source may include an LED. The matrix material may include a lens.