Laser-drilled microstructures for enhanced luminous efficiency and wide-angle emission in WLEDs

Area of Science:

• Materials Science
• Optoelectronics
• Photonics

Background:

• Phosphor-in-glass (PiG) structures are crucial for white light-emitting diodes (WLEDs).
• Optimizing light extraction and angular distribution in WLEDs remains a key challenge for enhanced performance.

Purpose of the Study:

• To enhance the optical performance of PiG structures for WLEDs.
• To investigate the integration of laser-fabricated microlens arrays (MLAs) onto phosphor surfaces.
• To analyze the impact of MLA structural parameters on light extraction and angular emission.

Main Methods:

• Hybrid approach combining PiG structures with laser-fabricated MLAs.
• Direct patterning of MLA structures using laser direct writing and drilling.
• Systematic investigation of varying microlens spacing (100–135 μm).
• Ray-tracing simulations based on geometric optics.

Main Results:

• Optimal performance achieved with 120 μm microlens spacing.
• Increased emission angle from 80° to 120°.
• Enhanced luminous efficacy by 12.5%.
• Improved scattering ratio from 51.4% to 80.3%.
• Increased color conversion efficiency from 64.7% to 74.6%.

Conclusions:

• Laser-fabricated MLAs effectively enhance optical performance of PiG structures.
• The proposed method offers a scalable, maskless, and practical approach for WLED improvement.
• Findings are significant for next-generation WLEDs in automotive and solid-state lighting.