Scattering Waveguide Fiber for Uniform White Illumination
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Solution Overview
Problem
Existing fiber-based illumination systems struggle to efficiently produce broadband visible light (white light) with uniform intensity and controlled color temperature along the length of the fiber, while minimizing thermal dissipation at the light conversion location.
Innovation Solution
A waveguide apparatus with scattering structures and a photo-luminescent medium is used to redirect primary light, converting it to secondary light, which combines with unabsorbed primary light to produce broadband illumination. The scattering structures are laser-induced and positioned to control the radiation pattern, and the photo-luminescent medium is optimized to enhance light conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light is injected into an optical fiber and transported to a remote location, then light can be delivered to a desired location, but the system cannot efficiently produce broadband visible light with uniform intensity and controlled color temperature
Solution Approach 1:
The patent applies local quality by introducing scattering structures at specific locations along the fiber and positioning photoluminescent layers at predetermined radial positions. These localized modifications create controlled radiation patterns that enable uniform broadband light output along the fiber length, resolving the contradiction between uniform illumination and energy efficiency.
Solution Approach 2:
The patent uses photoluminescent layers as intermediary materials that absorb primary light at one wavelength and convert it to secondary light at different wavelengths. This intermediary conversion process enables efficient broadband light production while maintaining uniform intensity distribution, addressing the energy efficiency problem.
2Productivity
If scattering structures are introduced to redirect light out of the fiber, then illumination can be produced along the fiber length, but thermal dissipation increases at the light conversion location
Solution Approach 1:
The patent segments the light conversion process by distributing multiple scattering structures and photoluminescent layers along the fiber length rather than concentrating conversion at a single location. This segmentation reduces thermal dissipation at any one point while maintaining overall illumination productivity.
Solution Approach 2:
The patent positions photoluminescent layers at predetermined radial positions within the fiber structure, utilizing the radial dimension to distribute light conversion pathways. This spatial distribution in multiple dimensions reduces thermal concentration while maintaining illumination output.
3Shape
If a blazed diffraction grating and convex lens are used to diffract and focus light, then a linear illumination field can be established, but the system cannot achieve uniform intensity and controlled color temperature
Solution Approach 1:
The patent changes the parameters of light interaction by using scattering structures with specific scattering angles and photoluminescent materials with particular emission characteristics. These parameter adjustments enable precise control over radiation patterns, intensity uniformity, and color temperature without requiring complex diffractive optics.
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 apparatus achieves homogeneous illumination with improved energy efficiency and reduced thermal dissipation by controlling the color temperature and intensity uniformity of the illumination along the waveguide length.
Implementation Method 1
The waveguide contains a number of scattering structures, which serve to re-distribute or redirect the propagating primary light out of a side surface of the waveguide
Implementation Method 2
A medium or layer of photo-luminescent material is provided, preferably outside of and running longitudinally along the waveguide, to absorb the re-directed primary light, and as a result emit a secondary, wavelength-converted light having a different wavelength than the primary light
Data Source
Figure 1a
Figure 1b
Figure 1c
AI summary
A waveguide such as optical fiber is to receive a primary light in a longitudinal (propagation) direction. The fiber has formed therein scattering structures that re-direct the propagating primary light out of the waveguide, for instance in a transverse direction. A photo-luminescent layer absorbs the re-directed primary light to thereby emit secondary wavelength converted light having a different wavelength than and broader bandwidth than the primary light, resulting in white illumination light, being the secondary light combined with any unabsorbed primary light. Other embodiments are also described and claimed.