Cup-shaped copper heat spreader in multi-chip high-power LEDs application

Area of Science:

• Materials Science
• Optoelectronics Engineering
• Thermal Management

Background:

• High-power light-emitting diodes (LEDs) require efficient thermal management to maintain performance and longevity.
• Existing heat dissipation methods for LED arrays can be insufficient, leading to performance degradation and reduced lifespan.
• Optimizing heat dissipation is crucial for advancing high-power LED applications.

Purpose of the Study:

• To develop and evaluate novel cup-shaped copper heat spreaders for high-power LED array modules.
• To enhance both heat dissipation and light extraction efficiency in LED arrays.
• To investigate the impact of cup-shaped copper heat spreaders on LED surface temperature and thermal resistance.

Main Methods:

• Fabrication of cup-shaped copper sheets using an electroplating technique.
• Direct contact of cup-shaped copper sheets with sapphire substrates for enhanced heat transfer.
• Testing of 3x3, 4x4, and 5x5 LED array modules with the developed heat spreaders.
• Measurement of surface temperature, thermal resistance, and light output power.

Main Results:

• Cup-shaped copper heat spreaders effectively reduced surface temperature and improved uniformity across LED chips.
• Significant reductions in thermal resistance were achieved: 0.7 K/W for 3x3, 0.6 K/W for 4x4, and 0.7 K/W for 5x5 modules.
• Light output power increased by 14%, 13%, and 12% for 3x3, 4x4, and 5x5 modules, respectively, at high current injection.
• Enhanced lateral light extraction and heat dissipation were observed.

Conclusions:

• The cup-shaped copper heat spreader is an effective solution for improving thermal management in high-power LED arrays.
• This design enhances both heat dissipation and light extraction, leading to improved LED performance and efficiency.
• The combination of cup-shaped copper with copper bulk and silver mirror further optimizes performance.