TIR Lens Color Mixing via Refractive Beads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current LED-based lighting systems face challenges in maintaining uniform color distribution and high color rendering index (CRI) across a wide range of angles, leading to non-uniform color variation and reduced light intensity when light sources are positioned off the optical axis, which affects applications such as medical procedures and display technologies.
Innovation Solution
A total-internal-reflection (TIR) lens and LED packaging method using a matrix material with dispersed beads of higher refractive index, which scatters and mixes light to provide centered and uniform illumination, enhancing light transmission efficiency and maintaining high CRI over a wide range of angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a secondary lens with light mixing design is used to reduce color variation, then color uniformity is improved, but light intensity output is reduced by 40-50%
Solution Approach 1:
The patent introduces a light mixing layer composed of transparent resin and dispersed transparent beads as an intermediary between the LED array and the external environment. This layer mixes light from multiple LEDs to reduce color variation while maintaining high light transmission, avoiding the 40-50% intensity loss associated with conventional secondary lenses.
Solution Approach 2:
The light mixing layer uses a composite material system consisting of transparent resin matrix with dispersed transparent beads having different refractive indices. This composite structure enables effective light mixing through refraction and scattering at the bead-resin interfaces while maintaining overall optical transparency, achieving both color uniformity and high light intensity.
2Illumination intensity
If light sources are positioned off the optical axis to increase luminosity, then light output is improved, but color distribution uniformity deteriorates
Solution Approach 1:
The light mixing layer acts as a mediator that receives light from off-axis positioned LED sources and redistributes it uniformly across the optical axis. The transparent beads in the mixing layer scatter and redirect light rays, ensuring that even though sources are positioned off-axis for maximum luminosity, the resulting color distribution remains uniform.
3Stability of the object's composition
If multiple monochromatic LED elements are used to produce white light, then color rendering is improved, but color variation with viewing angle increases
Solution Approach 1:
The light mixing layer serves as an intermediary that receives light from multiple monochromatic LED elements (red, green, blue, yellow) and thoroughly mixes them through refraction and scattering at the bead interfaces. This mixing process ensures that the combined white light maintains consistent color characteristics across a wide range of viewing angles, eliminating the angle-dependent color variation inherent in multi-LED arrays.
Solution Approach 2:
The patent utilizes changes in refractive index parameters by selecting transparent beads with refractive indices different from the surrounding resin matrix. This parameter difference creates refraction and scattering effects that effectively mix light from multiple monochromatic sources, producing angle-independent white light with consistent color rendering.
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 systems with secondary mixing lenses, providing uniform color and intensity illumination, and a CRI greater than 80-90, enabling improved LED-based light sources with higher optical performance and efficiency.
Implementation Method 1
the outer surface is shaped to provide total internal reflection
Implementation Method 2
The second end surface region includes a plurality of refractive surface regions positioned around the second end region of the open channel
Implementation Method 3
A total-internal-reflection (TIR) lens and LED packaging method using a matrix material with dispersed beads of higher refractive index, which scatters and mixes light
Data Source
AI summary
A total-internal-reflection (TIR) lens for color mixing includes a body member having an outer surface and an interior open channel extending longitudinally through the body member. The body member and the interior open channel are substantially symmetric with respect to an optical axis, and the outer surface is shaped to provide total internal reflection. The body member has a first end surface region at a first end of the open channel for accommodating a light source and a second end surface region opposite the first end region. The second end surface region includes a plurality of refractive surface regions positioned around the second end region of the open channel. The lens is configured to provide projected light substantially centered with respect to the optical axis when the light source is positioned off the optical axis. In a specific embodiment, a lighting apparatus for providing centered white light includes such a lens and a plurality of light sources.