Light Mixing Optics for Uniform LED Illumination
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Solution Overview
Problem
Current light-mixing systems for high-power light sources, such as LEDs, face challenges in producing uniformly mixed light and reducing source imaging, with limited efficiency and sub-par illumination characteristics, especially when dealing with multiple light sources of different colors.
Innovation Solution
A light-mixing lens design featuring a lens body with an input surface forming a cavity to receive light from one or more light sources, where the input surface is shaped to refract a significant portion of the light away from the optical axis and towards a peripheral surface, which is configured for total internal reflection, ensuring efficient mixing and uniform output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If textured surfaces are used to spread light from light sources, then light distribution is improved, but light mixing efficiency and illumination characteristics deteriorate
Solution Approach 1:
The input surface is divided into multiple zones (central region and peripheral regions) with different optical functions. The central region refracts light at specific angles while peripheral regions handle other angular ranges, enabling systematic light redistribution and improving both mixing efficiency and illumination uniformity
Solution Approach 2:
Different regions of the input surface are assigned different curvature profiles and refraction characteristics. The central portion has one optical configuration while peripheral portions have different configurations, allowing each zone to optimize light redirection for its specific function, thereby achieving high efficiency light mixing
2Device complexity
If conventional optics are used with multiple light sources, then system simplicity is maintained, but uniform light mixing and source imaging control deteriorate
Solution Approach 1:
The single optical component performs multiple functions: it acts as both a light guide and a mixing element, redirects light from multiple sources simultaneously, and controls source imaging all through its integrated multi-zone surface design, eliminating the need for separate optical elements
Solution Approach 2:
The input surface employs specific curvature profiles (concave, convex, or planar) in different zones to control light refraction angles. These curved surfaces systematically redirect light rays from multiple sources to achieve uniform angular distribution and prevent source imaging, improving mixing uniformity
3Illumination intensity
If light is refracted away from the optical axis to improve mixing, then light distribution uniformity is improved, but light loss increases
Solution Approach 1:
The optical design ensures continuous light propagation from the light sources through the lens to the target surface. By optimizing refraction angles and using total internal reflection at the peripheral surface, the system maintains continuous useful light action while achieving uniform distribution, minimizing energy loss
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 efficient light mixing with an efficiency of 70% or greater, effectively reducing source imaging and improving illumination characteristics by redirecting a high percentage of light from the input surface to the output surface, resulting in uniform and high-quality mixed light.
Implementation Method 1
The input surface can be shaped to refract substantially all of the light received at the input surface from the at least one light source away from the optical axis and to or towards the peripheral surface
Implementation Method 2
The peripheral surface can be configured such that substantially all light propagating thereto from the cavity is totally internally reflected to the output surface
Data Source
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AI summary
In one aspect, a light-mixing optic is disclosed for use with one or more light sources such as light emitting diodes. In one embodiment, an exemplary optic can include an optical body disposed about an optical axis and having an input and an output surface and a peripheral surface extending between the two. The input surface can form a central cavity for receiving light from the light sources, if not the light sources themselves. Further, the input surface can be shaped to refract substantially all of the light received from the one or more light sources away from the optical axis to the peripheral surface of the optic, where that light (e.g., substantially all of it) can be redirected (e.g., via total internal reflection or specular reflection) to the output surface. An array of micro-lenses or other surface features can be formed on the output surface. Further embodiments, as well as exemplary design methods, are also disclosed.