Packaging of InGaN stripe-shaped light-emitting diodes

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Lighting

Background:

• Conventional light-emitting diodes (LEDs) face challenges in achieving optimal light output, efficiency, and uniformity for general lighting applications.
• Existing packaging methods for LEDs can limit performance, particularly under high current operation and in terms of light extraction.
• There is a need for novel LED designs and packaging strategies to improve luminaire performance and energy efficiency.

Purpose of the Study:

• To fabricate and characterize Indium Gallium Nitride/Gallium Nitride (InGaN/GaN) stripe-shaped LEDs using flip-chip (FC-LED) and vertically mounted (VM-LED) packaging.
• To evaluate the performance benefits of these novel packaging schemes compared to conventional LED packaging for general lighting.
• To assess the suitability of stripe-shaped LEDs for luminaire assembly, focusing on emission uniformity and illumination area.

Main Methods:

• Fabrication of InGaN/GaN stripe-shaped LEDs in flip-chip and vertically mounted configurations.
• Performance testing of FC-LEDs and VM-LEDs, including efficiency at high current and light extraction.
• Assembly and optical performance comparison of an LED light tube using stripe-shaped LEDs versus conventional square-shaped LEDs using confocal microscopy.

Main Results:

• Flip-chip packaged LEDs (FC-LEDs) demonstrated sustained efficiency at high current due to effective heat sinking.
• Vertically mounted packaged LEDs (VM-LEDs) exhibited enhanced light extraction efficiency from two large emission surfaces.
• An LED light tube with stripe-shaped LEDs showed a threefold increase in illumination area and significantly improved emission uniformity compared to conventional LEDs, without efficiency loss.

Conclusions:

• Stripe-shaped InGaN/GaN LEDs with FC-LED and VM-LED packaging offer superior light output, efficiency, and uniformity for general lighting.
• These novel LEDs are well-suited for luminaire assembly due to their low luminous exitance and uniform emission properties.
• The developed LED light tube demonstrates the practical application of stripe-shaped LEDs, providing enhanced illumination performance for lighting solutions.