High Refractive Index TIR Lens for Solid State Lighting
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Solution Overview
Problem
Conventional LED-based lighting systems face challenges in achieving uniform color mixing across various viewing angles, heat management, and optical efficiency, particularly in high-power applications, where color separation and inefficient optics lead to suboptimal performance.
Innovation Solution
The use of a high refractive index polymeric material for total internal reflection (TIR) lenses, combined with a diffuser, to redirect and mix light efficiently, while maintaining a compact size and effective heat dissipation through remote phosphor layers and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional TIR lenses are used to achieve compact size, then device size is reduced, but optical efficiency deteriorates with losses of 30% or more
Solution Approach 1:
The patent changes the refractive index parameter of the lens material from conventional values (typically <1.5) to high refractive index values (≥1.6). This parameter change enables the TIR lens to maintain compact size while significantly improving optical efficiency by reducing light loss at interfaces and enhancing total internal reflection effectiveness.
2Stability of the object's composition
If intermediate diffusion mechanisms are used to mix colors of light, then color uniformity is improved, but optical efficiency deteriorates due to losses
Solution Approach 1:
The patent extracts the color mixing function from separate intermediate diffusion mechanisms and integrates it directly into the TIR lens structure. By incorporating phosphor materials directly into the lens, the system achieves color mixing through the lens's internal reflection surfaces without requiring additional lossy diffusion elements.
Solution Approach 2:
The patent merges multiple functions (light reflection, color mixing, and beam shaping) into a single integrated TIR lens structure. The phosphor-containing lens combines the optical function of a TIR lens with the color conversion function of phosphor materials, eliminating the need for separate diffusion mechanisms.
3Stability of the object's composition
If multiple bounces are used to improve color mixing, then color uniformity is improved, but energy loss increases with each bounce
Solution Approach 1:
The patent changes the refractive index parameter to high values (≥1.6), which increases the effectiveness of total internal reflection and reduces light loss at each bounce. This enables the system to achieve good color mixing through multiple internal reflections without suffering significant energy losses.
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 color uniformity and optical efficiency by minimizing light loss, reducing the need for multiple bounces, and maintaining the phosphor at a lower temperature for improved reliability and efficiency.
Implementation Method 1
A lens includes at least one total internal reflection (TIR) surface positioned to internally reflect incident light. The lens comprises a polymeric material having a refractive index of 1.6 or greater.
Implementation Method 2
Some of the blue light passes through the phosphor without being changed while a substantial portion of the light is downconverted to yellow.
Implementation Method 3
Many systems utilize heat sinks which must be in good thermal contact with the heat-generating light sources.
Data Source
AI summary
Optical elements having components made from high refractive index materials (RI≦1.6) and lamp assemblies incorporating such elements. Various optical elements, such as total internal reflection lenses, can be fabricated from materials having a higher index of refraction than materials typically used in such elements. The compact optical elements have at least one internal reflection surface that directs radiant energy (e.g., light) from a receiving end to a transmitting end. By using a high refractive index material, a lens can be fabricated that directs a greater portion of the light emitted from a source into the lens toward the transmitting end of the lens. Thus, less of the light spills out of the lens at a surface where emission is not intended, reducing the number of lossy bounces needed to direct the light in a particular direction.