Improved CCT uniformity of white LED using remote phosphor with patterned sapphire substrate

Area of Science:

• Optoelectronics
• Materials Science
• Solid-State Lighting

Background:

• Light-emitting diodes (LEDs) are crucial for energy-efficient lighting.
• Remote phosphor technology offers advantages in color quality and thermal management.
• Substrate design significantly impacts LED light distribution and performance.

Purpose of the Study:

• To evaluate the impact of patterned sapphire substrates on the light distribution of remote phosphor LEDs.
• To compare the performance of planar sapphire (PS), partially patterned sapphire (PPS), and fully patterned sapphire (FPS) substrates.
• To understand how substrate patterning affects correlated color temperature (CCT) uniformity.

Main Methods:

• Fabrication of remote phosphor LEDs using PS, PPS, and FPS substrates.
• Characterization of light distribution and far-field patterns.
• Analysis of correlated color temperature (CCT) uniformity across different substrate types.

Main Results:

• The LED with a fully patterned sapphire (FPS) substrate exhibited superior CCT uniformity in the far-field pattern compared to PS and PPS substrates.
• The enhanced scattering of blue light in the FPS substrate was identified as the primary factor for improved performance.
• Increased excitation of phosphor particles was observed with the FPS substrate.

Conclusions:

• Fully patterned sapphire (FPS) substrates significantly enhance the light distribution and CCT uniformity of remote phosphor LEDs.
• Substrate engineering, specifically patterning, is a viable strategy for optimizing LED performance.
• The findings provide insights for designing advanced LED packaging for improved lighting quality.