Improving LED CCT uniformity using micropatterned films optimized by combining ray tracing and FDTD methods.

Area of Science:

• Optics and Photonics
• Solid-state Lighting
• Materials Science

Background:

• Non-uniform correlated color temperature (CCT) is a persistent challenge in light-emitting diode (LED) technology.
• Remote phosphor LED lamps offer advantages but still face issues with light distribution and color consistency.

Purpose of the Study:

• To enhance the light distribution performance of remote phosphor LED lamps.
• To address the non-uniformity of correlated color temperature (CCT) in LED lighting.
• To develop a low-cost method for improving LED light quality.

Main Methods:

• Fabrication of a micropatterned array (MPA) optical film using a low-cost molding process.
• Optimization of MPA parameters (configuration, positioning, diameter) via finite-difference time-domain and ray-tracing simulations.
• Experimental verification of simulation findings.

Main Results:

• An optimized upward-facing convex-cone MPA film, with a diameter half that of the remote phosphor glass and affixed to its inward surface, demonstrated superior performance.
• The deviation in CCT distribution was reduced from 1033 K to 223 K.
• The optimized MPA film achieved an acceptable output power of 85.6%.

Conclusions:

• The developed MPA optical film effectively improves light distribution and CCT uniformity in remote phosphor LED lamps.
• The simulation and experimental results show close agreement, validating the approach.
• This method provides a viable strategy for optimizing optical films in diverse lighting applications.