Luminescent Light Guide Structure for Better Light Outcoupling
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Solution Overview
Problem
Existing lighting devices face inefficiencies in light outcoupling and spectral control, particularly in high brightness applications such as stage lighting and digital projection, due to high refractive index materials and rectangular cross-sections leading to significant light loss and difficulty in spectral tuning.
Innovation Solution
The use of hollow elongated light transmissive bodies with a cavity and a luminescent material, optionally filled with a lower refractive index material, and optical elements like CPCs to enhance light outcoupling and spectral control, allowing for efficient conversion and extraction of light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high refractive index materials are used in lighting devices, then light conversion efficiency is improved, but light outcoupling is significantly reduced
Solution Approach 1:
The lighting device is divided into multiple light transmissive bodies with different refractive indices. A first light transmissive body with high refractive index performs efficient wavelength conversion, while a second light transmissive body with lower refractive index facilitates light outcoupling. This segmentation allows each component to optimize its function without compromising the other.
Solution Approach 2:
The second light transmissive body with lower refractive index acts as an intermediary between the high refractive index first body and the external environment. It mediates the transition of light from the high refractive index medium to air, reducing total internal reflection and improving light extraction efficiency.
2Ease of manufacture
If rectangular cross-sections are used in light transmissive bodies, then manufacturing is simplified, but light loss increases
Solution Approach 1:
The patent employs light transmissive bodies with curved or rounded cross-sections instead of sharp rectangular edges. This curvature reduces light trapping effects and improves light extraction while maintaining manufacturing feasibility through processes like molding or extrusion.
3Use of energy by moving object
If luminescent material is distributed throughout the volume, then conversion is enhanced, but spectral tuning becomes difficult
Solution Approach 1:
The luminescent material is concentrated in specific regions (such as the first light transmissive body) rather than uniformly distributed. This localized placement allows for spectral tuning by selecting specific phosphor materials and concentrations in different zones, enabling versatile spectral control while maintaining high conversion efficiency.
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 configuration achieves higher light efficiency and spectral control, enabling brighter and more versatile lighting solutions with reduced manufacturing costs and improved reliability.
Implementation Method 1
the luminescent material is configured to convert at least part of light source light received at the radiation input face into luminescent material radiation
Implementation Method 2
the elongated light transmissive body is hollow over at least part of the length (L) thereby defining a cavity
Data Source
Figure 1A~1B
Figure 1C
Figure 1D~1E
AI summary
The invention provides a lighting device (1) comprising a luminescent element (5) comprising an elongated light transmissive body (100), the elongated light transmissive body (100) comprising a side face (140), wherein the elongated light transmissive body (100) comprises a luminescent material (120) configured to convert at least part of a light source light (11) selected from one or more of the UV, visible light, and IR received by the elongated light transmissive body (100) into luminescent material radiation (8). The invention further provides such luminescent element per se.