Elongated Light Mixer for Multicolor LED Homogeneity
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Solution Overview
Problem
Existing lighting devices with multicolored LEDs suffer from poor color and intensity homogeneity due to inefficient light coupling into light guides, particularly when using glass fiber bundles, leading to unfavorable coupling values as light moves away from the center.
Innovation Solution
A light mixer with a transparent, elongated design featuring three regions with different optical reflection properties, optimized for total internal reflection and beam path focusing, is used to improve light mixing and reduce losses during coupling into a smaller target cross-section, utilizing materials with a high refractive index like glass or plastic and applying optical coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the light source is located directly on the front face of the light guide for efficient coupling, then the coupling efficiency is improved, but the color and intensity homogeneity deteriorates
Solution Approach 1:
A light mixer is introduced as an intermediary component between the light source and the light guide. The light mixer receives light from the light source, performs internal reflections to homogenize the light distribution, and then couples the homogenized light into the light guide, thereby resolving the contradiction between coupling efficiency and homogeneity
Solution Approach 2:
The light mixing function is segmented from the direct coupling path. The light mixer divides the light path into multiple reflection paths within its structure, allowing different portions of light to undergo multiple reflections before entering the light guide, which homogenizes the output while maintaining coupling efficiency
2Use of energy by moving object
If multicolored LEDs are used as the light source, then the luminous efficacy is improved, but the color mixing quality deteriorates
Solution Approach 1:
The light mixer acts as a mediator that receives multicolored light from LEDs and performs internal reflections to thoroughly mix the different color components (red, green, blue) before coupling into the light guide, thereby achieving homogeneous color distribution while maintaining the high luminous efficacy of LED sources
Solution Approach 2:
The light mixer extends the light path in multiple dimensions through internal reflections off the side walls of the elongated mixing chamber. This multi-dimensional light path ensures that light from different LED positions and colors undergoes sufficient mixing before exiting, improving color homogeneity without sacrificing the energy efficiency of LED sources
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 enhances light mixing and reduces losses, achieving improved color and intensity homogeneity with minimal effort, ensuring efficient coupling and distribution of light from multicolored LEDs into a light guide.
Implementation Method 1
the light mixer 5 is designed to reflect the light rays passing through it by total internal reflection
Implementation Method 2
utilizing materials with a high refractive index like glass or plastic
Data Source
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AI summary
Lighting device with a multicolored light source (8) which couples light into a light guide (2) via an elongated light mixer (5), wherein the light guide (2) is fixed at one end (22) opposite the light mixer (5), and the light source (8) is positioned towards the end face (23) of the light mixer (5), wherein the light guide (2) is permanently connected to the light mixer (5) at one end (22) via an injection molding sprue, and the light mixer (5) is designed along its length such that at least 60% of the incident light undergoes at least two internal reflections before being coupled into the light guide (2).