Compact étendue-preserving light-mixing optics

Area of Science:

• Optics and Photonics
• Illumination Engineering

Background:

• Achieving uniform color mixing in multicolor light sources, such as multi-chip LEDs, is crucial for many lighting applications.
• Existing solutions can be bulky or inefficient, limiting their integration into compact luminaires.

Purpose of the Study:

• To introduce a novel, compact freeform optic designed for homogeneous color mixing of multicolor light sources.
• To evaluate the optical performance, efficiency, and compatibility of the proposed optic with existing luminaire designs.

Main Methods:

• Design and simulation of a freeform optic, termed the "Freeform Shell-Mixer", utilizing étendue-conserving Köhler integration.
• Ray tracing analysis to model light mixing, virtual source characteristics, and emission patterns.
• Assessment of manufacturability through compatibility with injection molding.

Main Results:

• The Freeform Shell-Mixer achieves over 95% optical efficiency.
• It transforms a multicolor source into a virtual source with uniform color mixing.
• The optic's minimal size (2x source size) and preserved emission pattern ensure luminaire performance.

Conclusions:

• The Freeform Shell-Mixer offers an efficient and compact solution for homogeneous color mixing in LED lighting.
• Its design is compatible with mass production via injection molding.
• The optic effectively preserves luminaire performance while enhancing color uniformity.